Sample records for platelet thrombus formation
-
PKCalpha regulates platelet granule secretion and thrombus formation in mice.
Konopatskaya, Olga; Gilio, Karen; Harper, Matthew T; Zhao, Yan; Cosemans, Judith M E M; Karim, Zubair A; Whiteheart, Sidney W; Molkentin, Jeffery D; Verkade, Paul; Watson, Steve P; Heemskerk, Johan W M; Poole, Alastair W
2009-02-01
Platelets are central players in atherothrombosis development in coronary artery disease. The PKC family provides important intracellular mechanisms for regulating platelet activity, and platelets express several members of this family, including the classical isoforms PKCalpha and PKCbeta and novel isoforms PKCdelta and PKCtheta. Here, we used a genetic approach to definitively demonstrate the role played by PKCalpha in regulating thrombus formation and platelet function. Thrombus formation in vivo was attenuated in Prkca-/- mice, and PKCalpha was required for thrombus formation in vitro, although this PKC isoform did not regulate platelet adhesion to collagen. The ablation of in vitro thrombus formation in Prkca-/- platelets was rescued by the addition of ADP, consistent with the key mechanistic finding that dense-granule biogenesis and secretion depend upon PKCalpha expression. Furthermore, defective platelet aggregation in response to either collagen-related peptide or thrombin could be overcome by an increase in agonist concentration. Evidence of overt bleeding, including gastrointestinal and tail bleeding, was not seen in Prkca-/- mice. In summary, the effects of PKCalpha ablation on thrombus formation and granule secretion may implicate PKCalpha as a drug target for antithrombotic therapy.
-
Platelet size and density affect shear-induced thrombus formation in tortuous arterioles
Chesnutt, Jennifer K. W.; Han, Hai-Chao
2013-10-01
Thrombosis accounts for 80% of deaths in patients with diabetes mellitus. Diabetic patients demonstrate tortuous microvessels and larger than normal platelets. Large platelets are associated with increased platelet activation and thrombosis, but the physical effects of large platelets in the microscale processes of thrombus formation are not clear. Therefore, the objective of this study was to determine the physical effects of mean platelet volume (MPV), mean platelet density (MPD) and vessel tortuosity on platelet activation and thrombus formation in tortuous arterioles. A computational model of the transport, shear-induced activation, collision, adhesion and aggregation of individual platelets was used to simulate platelet interactions and thrombus formation in tortuous arterioles. Our results showed that an increase in MPV resulted in a larger number of activated platelets, though MPD and level of tortuosity made little difference on platelet activation. Platelets with normal MPD yielded the lowest amount of mural thrombus. With platelets of normal MPD, the amount of mural thrombus decreased with increasing level of tortuosity but did not have a simple monotonic relationship with MPV. The physical mechanisms associated with MPV, MPD and arteriole tortuosity play important roles in platelet activation and thrombus formation.
-
Effect of red blood cells on platelet activation and thrombus formation in tortuous arterioles
Directory of Open Access Journals (Sweden)
Jennifer K. W. Chesnutt
2013-12-01
Full Text Available Thrombosis is a major contributor to cardiovascular disease, which can lead to myocardial infarction and stroke. Thrombosis may form in tortuous microvessels, which are often seen throughout the human body, but the microscale mechanisms and processes are not well understood. In straight vessels, the presence of red blood cells (RBCs is known to push platelets toward walls, which may affect platelet aggregation and thrombus formation. However in tortuous vessels, the effects of RBC interactions with platelets in thrombosis are largely unknown. Accordingly, the objective of this work was to determine the physical effects of RBCs, platelet size, and vessel tortuosity on platelet activation and thrombus formation in tortuous arterioles. A discrete element computational model was used to simulate the transport, collision, adhesion, aggregation, and shear-induced platelet activation of hundreds of individual platelets and RBCs in thrombus formation in tortuous arterioles. Results showed that high shear stress near the inner sides of curved arteriole walls activated platelets to initiate thrombosis. RBCs initially promoted platelet activation, but then collisions of RBCs with mural thrombi reduced the amount of mural thrombus and the size of emboli. In the absence of RBCs, mural thrombus mass was smaller in a highly tortuous arteriole compared to a less tortuous arteriole. In the presence of RBCs however, mural thrombus mass was larger in the highly tortuous arteriole compared to the less tortuous arteriole. As well, smaller platelet size yielded less mural thrombus mass and smaller emboli, either with or without RBCs. This study shed light on microscopic interactions of RBCs and platelets in tortuous microvessels, which have implications in various pathologies associated with thrombosis and bleeding.
-
Functional divergence of platelet protein kinase C (PKC) isoforms in thrombus formation on collagen.
Gilio, Karen; Harper, Matthew T; Cosemans, Judith M E M; Konopatskaya, Olga; Munnix, Imke C A; Prinzen, Lenneke; Leitges, Michael; Liu, Qinghang; Molkentin, Jeffery D; Heemskerk, Johan W M; Poole, Alastair W
2010-07-23
Arterial thrombosis, a major cause of myocardial infarction and stroke, is initiated by activation of blood platelets by subendothelial collagen. The protein kinase C (PKC) family centrally regulates platelet activation, and it is becoming clear that the individual PKC isoforms play distinct roles, some of which oppose each other. Here, for the first time, we address all four of the major platelet-expressed PKC isoforms, determining their comparative roles in regulating platelet adhesion to collagen and their subsequent activation under physiological flow conditions. Using mouse gene knock-out and pharmacological approaches in human platelets, we show that collagen-dependent alpha-granule secretion and thrombus formation are mediated by the conventional PKC isoforms, PKCalpha and PKCbeta, whereas the novel isoform, PKC, negatively regulates these events. PKCdelta also negatively regulates thrombus formation but not alpha-granule secretion. In addition, we demonstrate for the first time that individual PKC isoforms differentially regulate platelet calcium signaling and exposure of phosphatidylserine under flow. Although platelet deficient in PKCalpha or PKCbeta showed reduced calcium signaling and phosphatidylserine exposure, these responses were enhanced in the absence of PKC. In summary therefore, this direct comparison between individual subtypes of PKC, by standardized methodology under flow conditions, reveals that the four major PKCs expressed in platelets play distinct non-redundant roles, where conventional PKCs promote and novel PKCs inhibit thrombus formation on collagen.
-
Functional Divergence of Platelet Protein Kinase C (PKC) Isoforms in Thrombus Formation on Collagen*
Gilio, Karen; Harper, Matthew T.; Cosemans, Judith M. E. M.; Konopatskaya, Olga; Munnix, Imke C. A.; Prinzen, Lenneke; Leitges, Michael; Liu, Qinghang; Molkentin, Jeffery D.; Heemskerk, Johan W. M.; Poole, Alastair W.
2010-01-01
Arterial thrombosis, a major cause of myocardial infarction and stroke, is initiated by activation of blood platelets by subendothelial collagen. The protein kinase C (PKC) family centrally regulates platelet activation, and it is becoming clear that the individual PKC isoforms play distinct roles, some of which oppose each other. Here, for the first time, we address all four of the major platelet-expressed PKC isoforms, determining their comparative roles in regulating platelet adhesion to collagen and their subsequent activation under physiological flow conditions. Using mouse gene knock-out and pharmacological approaches in human platelets, we show that collagen-dependent α-granule secretion and thrombus formation are mediated by the conventional PKC isoforms, PKCα and PKCβ, whereas the novel isoform, PKCθ, negatively regulates these events. PKCδ also negatively regulates thrombus formation but not α-granule secretion. In addition, we demonstrate for the first time that individual PKC isoforms differentially regulate platelet calcium signaling and exposure of phosphatidylserine under flow. Although platelet deficient in PKCα or PKCβ showed reduced calcium signaling and phosphatidylserine exposure, these responses were enhanced in the absence of PKCθ. In summary therefore, this direct comparison between individual subtypes of PKC, by standardized methodology under flow conditions, reveals that the four major PKCs expressed in platelets play distinct non-redundant roles, where conventional PKCs promote and novel PKCs inhibit thrombus formation on collagen. PMID:20479008
-
Genetic analysis of the role of protein kinase Ctheta in platelet function and thrombus formation.
Directory of Open Access Journals (Sweden)
Kellie J Hall
2008-09-01
Full Text Available PKCtheta is a novel protein kinase C isozyme, predominately expressed in T cells and platelets. PKCtheta(-/- T cells exhibit reduced activation and PKCtheta(-/- mice are resistant to autoimmune disease, making PKCtheta an attractive therapeutic target for immune modulation. Collagen is a major agonist for platelets, operating through an immunoreceptor-like signalling pathway from its receptor GPVI. Although it has recently been shown that PKCtheta positively regulates outside-in signalling through integrin alpha(IIbbeta(3 in platelets, the role of PKCtheta in GPVI-dependent signalling and functional activation of platelets has not been assessed.In the present study we assessed static adhesion, cell spreading, granule secretion, integrin alpha(IIbbeta(3 activation and platelet aggregation in washed mouse platelets lacking PKCtheta. Thrombus formation on a collagen-coated surface was assessed in vitro under flow. PKCtheta(-/- platelets exhibited reduced static adhesion and filopodia generation on fibrinogen, suggesting that PKCtheta positively regulates outside-in signalling, in agreement with a previous report. In contrast, PKCtheta(-/- platelets also exhibited markedly enhanced GPVI-dependent alpha-granule secretion, although dense granule secretion was unaffected, suggesting that PKCtheta differentially regulates these two granules. Inside-out regulation of alpha(IIbbeta(3 activation was also enhanced downstream of GPVI stimulation. Although this did not result in increased aggregation, importantly thrombus formation on collagen under high shear (1000 s(-1 was enhanced.These data suggest that PKCtheta is an important negative regulator of thrombus formation on collagen, potentially mediated by alpha-granule secretion and alpha(IIbbeta(3 activation. PKCtheta therefore may act to restrict thrombus growth, a finding that has important implications for the development and safe clinical use of PKCtheta inhibitors.
-
Cathepsin G-dependent modulation of platelet thrombus formation in vivo by blood neutrophils.
Directory of Open Access Journals (Sweden)
Nauder Faraday
Full Text Available Neutrophils are consistently associated with arterial thrombotic morbidity in human clinical studies but the causal basis for this association is unclear. We tested the hypothesis that neutrophils modulate platelet activation and thrombus formation in vivo in a cathepsin G-dependent manner. Neutrophils enhanced aggregation of human platelets in vitro in dose-dependent fashion and this effect was diminished by pharmacologic inhibition of cathepsin G activity and knockdown of cathepsin G expression. Tail bleeding time in the mouse was prolonged by a cathepsin G inhibitor and in cathepsin G knockout mice, and formation of neutrophil-platelet conjugates in blood that was shed from transected tails was reduced in the absence of cathepsin G. Bleeding time was highly correlated with blood neutrophil count in wildtype but not cathepsin G deficient mice. In the presence of elevated blood neutrophil counts, the anti-thrombotic effect of cathepsin G inhibition was greater than that of aspirin and additive to it when administered in combination. Both pharmacologic inhibition of cathepsin G and its congenital absence prolonged the time for platelet thrombus to form in ferric chloride-injured mouse mesenteric arterioles. In a vaso-occlusive model of ischemic stroke, inhibition of cathepsin G and its congenital absence improved cerebral blood flow, reduced histologic brain injury, and improved neurobehavioral outcome. These experiments demonstrate that neutrophil cathepsin G is a physiologic modulator of platelet thrombus formation in vivo and has potential as a target for novel anti-thrombotic therapies.
-
Genetic Analysis of the Role of Protein Kinase Cθ in Platelet Function and Thrombus Formation
Hall, Kellie J.; Harper, Matthew T.; Gilio, Karen; Cosemans, Judith M.; Heemskerk, Johan W. M.; Poole, Alastair W.
2008-01-01
Background PKCθ is a novel protein kinase C isozyme, predominately expressed in T cells and platelets. PKCθ−/− T cells exhibit reduced activation and PKCθ−/− mice are resistant to autoimmune disease, making PKCθ an attractive therapeutic target for immune modulation. Collagen is a major agonist for platelets, operating through an immunoreceptor-like signalling pathway from its receptor GPVI. Although it has recently been shown that PKCθ positively regulates outside-in signalling through integrin αIIbβ3 in platelets, the role of PKCθ in GPVI-dependent signalling and functional activation of platelets has not been assessed. Methodology/Principal Findings In the present study we assessed static adhesion, cell spreading, granule secretion, integrin αIIbβ3 activation and platelet aggregation in washed mouse platelets lacking PKCθ. Thrombus formation on a collagen-coated surface was assessed in vitro under flow. PKCθ−/− platelets exhibited reduced static adhesion and filopodia generation on fibrinogen, suggesting that PKCθ positively regulates outside-in signalling, in agreement with a previous report. In contrast, PKCθ−/− platelets also exhibited markedly enhanced GPVI-dependent α-granule secretion, although dense granule secretion was unaffected, suggesting that PKCθ differentially regulates these two granules. Inside-out regulation of αIIbβ3 activation was also enhanced downstream of GPVI stimulation. Although this did not result in increased aggregation, importantly thrombus formation on collagen under high shear (1000 s−1) was enhanced. Conclusions/Significance These data suggest that PKCθ is an important negative regulator of thrombus formation on collagen, potentially mediated by α-granule secretion and αIIbβ3 activation. PKCθ therefore may act to restrict thrombus growth, a finding that has important implications for the development and safe clinical use of PKCθ inhibitors. PMID:18815612
-
Importance of Endogenous Fibrinolysis in Platelet Thrombus Formation.
Gue, Ying X; Gorog, Diana A
2017-08-25
The processes of thrombosis and coagulation are finely regulated by endogenous fibrinolysis maintaining healthy equilibrium. When the balance is altered in favour of platelet activation and/or coagulation, or if endogenous fibrinolysis becomes less efficient, pathological thrombosis can occur. Arterial thrombosis remains a major cause of morbidity and mortality in the world despite advances in medical therapies. The role endogenous fibrinolysis in the pathogenesis of arterial thrombosis has gained increasing attention in recent years as it presents novel ways to prevent and treat existing diseases. In this review article, we discuss the role of endogenous fibrinolysis in platelet thrombus formation, methods of measurement of fibrinolytic activity, its role in predicting cardiovascular diseases and clinical outcomes and future directions.
-
Protein kinase C mediates platelet secretion and thrombus formation through protein kinase D2.
Konopatskaya, Olga; Matthews, Sharon A; Harper, Matthew T; Gilio, Karen; Cosemans, Judith M E M; Williams, Christopher M; Navarro, Maria N; Carter, Deborah A; Heemskerk, Johan W M; Leitges, Michael; Cantrell, Doreen; Poole, Alastair W
2011-07-14
Platelets are highly specialized blood cells critically involved in hemostasis and thrombosis. Members of the protein kinase C (PKC) family have established roles in regulating platelet function and thrombosis, but the molecular mechanisms are not clearly understood. In particular, the conventional PKC isoform, PKCα, is a major regulator of platelet granule secretion, but the molecular pathway from PKCα to secretion is not defined. Protein kinase D (PKD) is a family of 3 kinases activated by PKC, which may represent a step in the PKC signaling pathway to secretion. In the present study, we show that PKD2 is the sole PKD member regulated downstream of PKC in platelets, and that the conventional, but not novel, PKC isoforms provide the upstream signal. Platelets from a gene knock-in mouse in which 2 key phosphorylation sites in PKD2 have been mutated (Ser707Ala/Ser711Ala) show a significant reduction in agonist-induced dense granule secretion, but not in α-granule secretion. This deficiency in dense granule release was responsible for a reduced platelet aggregation and a marked reduction in thrombus formation. Our results show that in the molecular pathway to secretion, PKD2 is a key component of the PKC-mediated pathway to platelet activation and thrombus formation through its selective regulation of dense granule secretion.
-
Thrombus Formation at High Shear Rates.
Casa, Lauren D C; Ku, David N
2017-06-21
The final common pathway in myocardial infarction and ischemic stroke is occlusion of blood flow from a thrombus forming under high shear rates in arteries. A high-shear thrombus forms rapidly and is distinct from the slow formation of coagulation that occurs in stagnant blood. Thrombosis at high shear rates depends primarily on the long protein von Willebrand factor (vWF) and platelets, with hemodynamics playing an important role in each stage of thrombus formation, including vWF binding, platelet adhesion, platelet activation, and rapid thrombus growth. The prediction of high-shear thrombosis is a major area of biofluid mechanics in which point-of-care testing and computational modeling are promising future directions for clinically relevant research. Further research in this area will enable identification of patients at high risk for arterial thrombosis, improve prevention and treatment based on shear-dependent biological mechanisms, and improve blood-contacting device design to reduce thrombosis risk.
-
Directory of Open Access Journals (Sweden)
Wei Li
Full Text Available Platelets play a pivotal role in atherothrombosis and the antiplatelet agents have been proved to be useful in preventing onset of acute clinical events including myocardial infarction and stroke. Increasing number of natural compounds has been identified to be potential antiplatelet agents. Here we report the antiplatelet effect of glaucocalyxin A (GLA, an ent-diterpenoid that we isolated and purified from the aerial parts of Rabdosia japonica (Burm. f. var. glaucocalyx (Maxim. Hara, and investigate the molecular mechanisms by which GLA inhibits platelet activation and thrombus formation. The effect of GLA on platelet activation was measured using platelets freshly isolated from peripheral blood of healthy donors. Results showed that pretreatment of human platelets with lower concentrations of GLA (0.01 μg/ml, 0.1 μg/ml significantly inhibited platelet aggregation induced by collagen (P<0.001 and CRP (P<0.01, a synthetic GPVI ligand, but not by ADP and U46619. Accordingly, GLA inhibited collagen-stimulated tyrosine phosphorylation of Syk, LAT, and phospholipase Cγ2, the signaling events in collagen receptor GPⅥ pathway. GLA also inhibited platelet p-selectin secretion and integrin activation by convulxin, a GPVI selective ligand. Additionally, GLA was found to inhibit low-dose thrombin-induced platelet activation. Using a flow chamber device, GLA was found to attenuate platelet adhesion on collagen surfaces in high shear condition. In vivo studies showed that GLA administration increased the time for complete occlusion upon vascular injury in mice, but did not extend tail-bleeding time when mice were administered with relatively lower doses of GLA. Therefore, the present results provide the molecular basis for the inhibition effect of GLA on platelet activation and its in vivo effect on thrombus formation, suggesting that GLA could potentially be developed as an antiplatelet and antithrombotic agent.
-
Gilio, Karen; Munnix, Imke C A; Mangin, Pierre; Cosemans, Judith M E M; Feijge, Marion A H; van der Meijden, Paola E J; Olieslagers, Servé; Chrzanowska-Wodnicka, Magdalena B; Lillian, Rivka; Schoenwaelder, Simone; Koyasu, Shigeo; Sage, Stewart O; Jackson, Shaun P; Heemskerk, Johan W M
2009-12-04
Platelets are activated by adhesion to vascular collagen via the immunoglobulin receptor, glycoprotein VI (GPVI). This causes potent signaling toward activation of phospholipase Cgamma2, which bears similarity to the signaling pathway evoked by T- and B-cell receptors. Phosphoinositide 3-kinase (PI3K) plays an important role in collagen-induced platelet activation, because this activity modulates the autocrine effects of secreted ADP. Here, we identified the PI3K isoforms directly downstream of GPVI in human and mouse platelets and determined their role in GPVI-dependent thrombus formation. The targeting of platelet PI3Kalpha or -beta strongly and selectively suppressed GPVI-induced Ca(2+) mobilization and inositol 1,4,5-triphosphate production, thus demonstrating enhancement of phospholipase Cgamma2 by PI3Kalpha/beta. That PI3Kalpha and -beta have a non-redundant function in GPVI-induced platelet activation and thrombus formation was concluded from measurements of: (i) serine phosphorylation of Akt, (ii) dense granule secretion, (iii) intracellular Ca(2+) increases and surface expression of phosphatidylserine under flow, and (iv) thrombus formation, under conditions where PI3Kalpha/beta was blocked or p85alpha was deficient. In contrast, GPVI-induced platelet activation was insensitive to inhibition or deficiency of PI3Kdelta or -gamma. Furthermore, PI3Kalpha/beta, but not PI3Kgamma, contributed to GPVI-induced Rap1b activation and, surprisingly, also to Rap1b-independent platelet activation via GPVI. Together, these findings demonstrate that both PI3Kalpha and -beta isoforms are required for full GPVI-dependent platelet Ca(2+) signaling and thrombus formation, partly independently of Rap1b. This provides a new mechanistic explanation for the anti-thrombotic effect of PI3K inhibition and makes PI3Kalpha an interesting new target for anti-platelet therapy.
-
RhoG protein regulates platelet granule secretion and thrombus formation in mice.
Goggs, Robert; Harper, Matthew T; Pope, Robert J; Savage, Joshua S; Williams, Christopher M; Mundell, Stuart J; Heesom, Kate J; Bass, Mark; Mellor, Harry; Poole, Alastair W
2013-11-22
Rho GTPases such as Rac, RhoA, and Cdc42 are vital for normal platelet function, but the role of RhoG in platelets has not been studied. In other cells, RhoG orchestrates processes integral to platelet function, including actin cytoskeletal rearrangement and membrane trafficking. We therefore hypothesized that RhoG would play a critical role in platelets. Here, we show that RhoG is expressed in human and mouse platelets and is activated by both collagen-related peptide (CRP) and thrombin stimulation. We used RhoG(-/-) mice to study the function of RhoG in platelets. Integrin activation and aggregation were reduced in RhoG(-/-) platelets stimulated by CRP, but responses to thrombin were normal. The central defect in RhoG(-/-) platelets was reduced secretion from α-granules, dense granules, and lysosomes following CRP stimulation. The integrin activation and aggregation defects could be rescued by ADP co-stimulation, indicating that they are a consequence of diminished dense granule secretion. Defective dense granule secretion in RhoG(-/-) platelets limited recruitment of additional platelets to growing thrombi in flowing blood in vitro and translated into reduced thrombus formation in vivo. Interestingly, tail bleeding times were normal in RhoG(-/-) mice, suggesting that the functions of RhoG in platelets are particularly relevant to thrombotic disorders.
-
Kuijpers, M J E; Gilio, K; Reitsma, S; Nergiz-Unal, R; Prinzen, L; Heeneman, S; Lutgens, E; van Zandvoort, M A M J; Nieswandt, B; Egbrink, M G A Oude; Heemskerk, J W M
2009-01-01
Atherothrombosis is a major cause of cardiovascular events. However, animal models to study this process are scarce. We describe the first murine model of acute thrombus formation upon plaque rupture to study atherothrombosis by intravital fluorescence microscopy. Localized rupture of an atherosclerotic plaque in a carotid artery from Apoe(-/-) mice was induced in vivo using ultrasound. Rupture of the plaque and formation of localized thrombi were verified by two-photon laser scanning microscopy (TPLSM) in isolated arteries, and by immunohistochemistry. The thrombotic reaction was quantified by intravital fluorescence microscopy. Inspection of the ultrasound-treated plaques by histochemistry and TPLSM demonstrated local damage, collagen exposure, luminal thrombus formation as well as intra-plaque intrusion of erythrocytes and fibrin. Ultrasound treatment of healthy carotid arteries resulted in endothelial damage and limited platelet adhesion. Real-time intravital fluorescence microscopy demonstrated rapid platelet deposition on plaques and formation of a single thrombus that remained subocclusive. The thrombotic process was antagonized by thrombin inhibition, or by blocking of collagen or adenosine diphosphate receptor pathways. Multiple thrombi were formed in 70% of mice lacking CD40L. Targeted rupture of murine plaques results in collagen exposure and non-occlusive thrombus formation. The thrombotic process relies on platelet activation as well as on thrombin generation and coagulation, and is sensitive to established and novel antithrombotic medication. This model provides new possibilities to study atherothrombosis in vivo.
-
International Nuclear Information System (INIS)
Perlman, S.B.; Hammes, R.J.; Besozzi, M.C.; Folts, J.D.; Mosher, D.F.
1987-01-01
There are many methods available for the detection of thrombosis, none of which are noninvasive, rapid and accurate. Thrombosponding is a platelet protein that is present in the developing thrombus and may be an effective substance to use for imaging thrombosis. Vascular stenosis and thrombosis were produced in coronary, carotid and femoral arteries in eleven adult mongrel dogs. 131 I labeled thrombosponding was administered to each animal to determine whether the radiotracer accumulated at the site of thrombus formation. The radioactivity per gram of vessels with thrombi was significantly different from the control vessels or whole blood (p=0.0037 and p=0.015, respectively, paired t-test). This preliminary work suggests that iodinated thrombosponding accumulates at the site of thrombus formation. Labeled thrombosponding may be a rapid, safe and accurate method of detecting arterial thrombosis. (orig.)
-
Gilio, Karen; van Kruchten, Roger; Braun, Attila; Berna-Erro, Alejandro; Feijge, Marion A H; Stegner, David; van der Meijden, Paola E J; Kuijpers, Marijke J E; Varga-Szabo, David; Heemskerk, Johan W M; Nieswandt, Bernhard
2010-07-30
In platelets, STIM1 has been recognized as the key regulatory protein in store-operated Ca(2+) entry (SOCE) with Orai1 as principal Ca(2+) entry channel. Both proteins contribute to collagen-dependent arterial thrombosis in mice in vivo. It is unclear whether STIM2 is involved. A key platelet response relying on Ca(2+) entry is the surface exposure of phosphatidylserine (PS), which accomplishes platelet procoagulant activity. We studied this response in mouse platelets deficient in STIM1, STIM2, or Orai1. Upon high shear flow of blood over collagen, Stim1(-/-) and Orai1(-/-) platelets had greatly impaired glycoprotein (GP) VI-dependent Ca(2+) signals, and they were deficient in PS exposure and thrombus formation. In contrast, Stim2(-/-) platelets reacted normally. Upon blood flow in the presence of thrombin generation and coagulation, Ca(2+) signals of Stim1(-/-) and Orai1(-/-) platelets were partly reduced, whereas the PS exposure and formation of fibrin-rich thrombi were normalized. Washed Stim1(-/-) and Orai1(-/-) platelets were deficient in GPVI-induced PS exposure and prothrombinase activity, but not when thrombin was present as co-agonist. Markedly, SKF96365, a blocker of (receptor-operated) Ca(2+) entry, inhibited Ca(2+) and procoagulant responses even in Stim1(-/-) and Orai1(-/-) platelets. These data show for the first time that: (i) STIM1 and Orai1 jointly contribute to GPVI-induced SOCE, procoagulant activity, and thrombus formation; (ii) a compensating Ca(2+) entry pathway is effective in the additional presence of thrombin; (iii) platelets contain two mechanisms of Ca(2+) entry and PS exposure, only one relying on STIM1-Orai1 interaction.
-
Role of newly formed platelets in thrombus formation in rat after clopidogrel treatment
DEFF Research Database (Denmark)
Kuijpers, Marijke J E; Megens, Remco T A; Nikookhesal, Elham
2011-01-01
Platelet P2Y₁₂ receptors play an important role in arterial thrombosis by stimulating thrombus growth. Both irreversibly (clopidogrel) and reversibly binding (ticagrelor, AZD6140) P2Y₁₂ antagonists are clinically used for restricted periods, but possible differences in platelet function recovery ...
-
Imaging thrombus with radiolabelled monoclonal antibody to platelets
International Nuclear Information System (INIS)
Loutfi, I.; Peters, A.M.; Lavender, J.P.; Epenetos, A.A.
1988-01-01
Indium-111-hydroxyquinoline labelled platelets, though useful in the detection of thrombus, have not gained widespread use owing to the time and technical skill required for their preparation. A study was therefore conducted evaluating a new method of imaging thrombus with platelets radiolabelled with a 111 In labelled monoclonal antibody, P 256 , directed to the platelet surface glycoprotein complex IIb/IIIa. When the number of receptors occupied by P 256 was less than 3% of the total available on the platelet surface platelet function, as assessed by platelet aggregometry, was undisturbed. P 256 was radiolabelled with 111 In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo - that is, by direct intravenous injection of P 256 - in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The 111 In kinetics recorded after intravenous P 256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P 256 , three had documented thrombus, tow of whom gave positive results on P 256 platelet scintigraphy. The third subject had chromic deep venous thrombosis and was scintigraphically negative. Imaging thrombus using a radiolabelled monoclonal antibody directed to platelets appears to offer great potential as a simple, non-invasive approach to the diagnosis of thrombosis. 3 refs. (Author)
-
Gilio, Karen; van Kruchten, Roger; Braun, Attila; Berna-Erro, Alejandro; Feijge, Marion A. H.; Stegner, David; van der Meijden, Paola E. J.; Kuijpers, Marijke J. E.; Varga-Szabo, David; Heemskerk, Johan W. M.; Nieswandt, Bernhard
2010-01-01
In platelets, STIM1 has been recognized as the key regulatory protein in store-operated Ca2+ entry (SOCE) with Orai1 as principal Ca2+ entry channel. Both proteins contribute to collagen-dependent arterial thrombosis in mice in vivo. It is unclear whether STIM2 is involved. A key platelet response relying on Ca2+ entry is the surface exposure of phosphatidylserine (PS), which accomplishes platelet procoagulant activity. We studied this response in mouse platelets deficient in STIM1, STIM2, or Orai1. Upon high shear flow of blood over collagen, Stim1−/− and Orai1−/− platelets had greatly impaired glycoprotein (GP) VI-dependent Ca2+ signals, and they were deficient in PS exposure and thrombus formation. In contrast, Stim2−/− platelets reacted normally. Upon blood flow in the presence of thrombin generation and coagulation, Ca2+ signals of Stim1−/− and Orai1−/− platelets were partly reduced, whereas the PS exposure and formation of fibrin-rich thrombi were normalized. Washed Stim1−/− and Orai1−/− platelets were deficient in GPVI-induced PS exposure and prothrombinase activity, but not when thrombin was present as co-agonist. Markedly, SKF96365, a blocker of (receptor-operated) Ca2+ entry, inhibited Ca2+ and procoagulant responses even in Stim1−/− and Orai1−/− platelets. These data show for the first time that: (i) STIM1 and Orai1 jointly contribute to GPVI-induced SOCE, procoagulant activity, and thrombus formation; (ii) a compensating Ca2+ entry pathway is effective in the additional presence of thrombin; (iii) platelets contain two mechanisms of Ca2+ entry and PS exposure, only one relying on STIM1-Orai1 interaction. PMID:20519511
-
Larson, Mark K; Tormoen, Garth W; Weaver, Lucinda J; Luepke, Kristen J; Patel, Ishan A; Hjelmen, Carl E; Ensz, Nicole M; McComas, Leah S; McCarty, Owen J T
2013-02-01
Several studies have implicated the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in inhibition of normal platelet function, suggesting a role for platelets in EPA- and DHA-mediated cardioprotection. However, it is unclear whether the cardioprotective mechanisms arise from alterations to platelet-platelet, platelet-matrix, or platelet-coagulation factor interactions. Our previous results led us to hypothesize that EPA and DHA alter the ability of platelets to catalyze the generation of thrombin. We tested this hypothesis by exogenously modifying platelet membranes with EPA and DHA, which resulted in compositional changes analogous to increased dietary EPA and DHA intake. Platelets treated with EPA and DHA showed reductions in the rate of thrombin generation and exposure of platelet phosphatidylserine. In addition, treatment of platelets with EPA and DHA decreased thrombus formation and altered the processing of thrombin precursor proteins. Furthermore, treatment of whole blood with EPA and DHA resulted in increased occlusion time and a sharply reduced accumulation of fibrin under flow conditions. These results demonstrate that EPA and DHA inhibit, but do not eliminate, the ability of platelets to catalyze thrombin generation in vitro. The ability of EPA and DHA to reduce the procoagulant function of platelets provides a possible mechanism behind the cardioprotective phenotype in individuals consuming high levels of EPA and DHA.
-
Reheman, Adili; Tasneem, Subia; Ni, Heyu; Hayward, Catherine P M
2010-05-01
Multimerin 1 is a stored platelet and endothelial cell adhesive protein that shows significant conservation. In vitro, multimerin 1 supports platelet adhesion and it also binds to collagen and enhances von Willebrand factor-dependent platelet adhesion to collagen. As selective, multimerin 1 deficient mice have not been generated, we investigated multimerin 1 effects on platelet adhesion using a subpopulation of C57BL/6J mice with tandem deletion of the genes for multimerin 1 and alpha-synuclein, a protein that inhibits alpha-granule release in vitro. We postulated that multimerin 1/alpha-synuclein deficient mice might show impaired platelet adhesive function from multimerin 1 deficiency and increased alpha-granule release from alpha-synuclein deficiency. Platelet function was assessed by intravital microscopy, after ferric chloride injury, using untreated and human multimerin 1-transfused multimerin 1/alpha-synuclein deficient mice, and by in vitro assays of adhesion, aggregation and thrombin-induced P-selectin release. Multimerin 1/alpha-synuclein deficient mice showed impaired platelet adhesion and their defective thrombus formation at sites of vessel injury improved with multimerin 1 transfusion. Although multimerin 1/alpha-synuclein deficient platelets showed increased P-selectin release at low thrombin concentrations, they also showed impaired adhesion to collagen, and attenuated aggregation with thrombin, that improved with added multimerin 1. Our data suggest that multimerin 1 supports platelet adhesive functions and thrombus formation, which will be important to verify by generating and testing selective multimerin 1 deficient mice. Copyright (c) 2010. Published by Elsevier Ltd.
-
Imaging thrombus with radiolabelled monoclonal antibody to platelets
Energy Technology Data Exchange (ETDEWEB)
Peters, A.M.; Lavender, J.P.; Needham, S.G.; Loutfi, I.; Snook, D.; Epenetos, A.A.; Lumley, P.; Keery, R.J.; Hogg, N.
1986-12-13
A study was conducted evaluating a method of imaging thrombus with platelets radiolabelled with a /sup 111/In labelled monoclonal antibody, P256, directed to the platelet surface glycoprotein complex IIb/IIIa. when the number of receptors occupied by P256 was less than 3% of the total available on the platelet surface, platelet function was undisturbed. P256 was radiolabelled with /sup 111/In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The /sup 111/In kinetics recorded after intravenous P256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P256, three had documented thrombus, two of whom gave positive results on P256 platelet scintigraphy. The third had chronic deep venous thrombosis and was scintigraphically negative.
-
International Nuclear Information System (INIS)
Hanson, S.R.; Paxton, L.D.; Harker, L.A.
1986-01-01
To measure the rate, extent, and time course of arterial mural thrombus formation in vivo and to assess the effects of antiplatelet therapy in that setting, we have studied autologous 111 In-platelet deposition induced by experimental iliac artery aneurysms in baboons. Scintillation camera imaging analyses were performed at 1, 24, 48, and 72 hours after implantation of the device. Correction for tissue attenuation was determined by using a small, comparably located 111 In source implanted at the time of surgery. In five animals, 111 In-platelet activity accumulated progressively after device implantation, reaching a maximum after the third day. Repeat image analysis carried out 2 weeks after the surgical procedure also showed progressive accumulation of 111 In-platelets over 3 days but at markedly reduced amounts as compared with the initial study. In five additional animals, treatment with a combination of aspirin and dipyridamole begun 1 hour after surgical implantation reduced 111 In-platelet deposition to negligible levels by the third day. Although platelet survival time was shortened and platelet turnover was reciprocally increased in all operated animals, platelet survival and turnover were not affected by antiplatelet therapy. We conclude that, in contrast to platelet survival and turnover measurements, 111 In-platelet imaging is a reliable and sensitive method for localizing and quantifying focal arterial thrombi and for assessing the effects of antiplatelet therapy
-
Platelet endothelial cell adhesion molecule 1 deficiency misguides venous thrombus resolution.
Kellermair, Joerg; Redwan, Bassam; Alias, Sherin; Jabkowski, Joerg; Panzenboeck, Adelheid; Kellermair, Lukas; Winter, Max P; Weltermann, Ansgar; Lang, Irene M
2013-11-07
Platelet endothelial cell adhesion molecule 1 (PECAM-1) is involved in leukocyte migration and angiogenesis, which are key components of venous thrombus resolution. This study investigated the effect of PECAM-1 deficiency on thrombus resolution in FVB/n mice and the extent to which levels of soluble PECAM-1 (sPECAM-1) correlate with delayed thrombus resolution in humans after acute symptomatic deep vein thrombosis (DVT). In a mouse stagnant flow venous thrombosis model Pecam-1(-/-) thrombi were larger, persisted for longer periods of time, and displayed attenuated macrophage invasion and decreased vessel formation in the presence of increased fibrosis. In humans, higher levels of truncated plasma sPECAM-1 possibly cleaved from cell surfaces, were found in patients with delayed thrombus resolution (assessed via duplex-based thrombus scoring) relative to those whose thrombi resolved (median, 25th/75th percentile): 92.5 (87.7/103.4) ng/mL vs 71.5 (51.1/81.0) ng/mL; P deep vein thrombus specimens stained positively with antibodies specific for the extracellular, but not the cytoplasmic domain of PECAM-1, consistent with accumulation of cleaved PECAM-1. Our data suggest a regulatory role of PECAM-1 in venous thrombus resolution and suggest a predictive value of sPECAM-1 for postthrombotic syndrome (PTS) after acute DVT.
-
Annarapu, Gowtham K; Singhal, Rashi; Peng, Yuandong; Guchhait, Prasenjit
2016-01-01
Reports including our own describe that intravascular hemolysis increases the risk of thrombosis in hemolytic disorders. Our recent study shows that plasma Hb concentrations correlate directly with platelet activation in patients with paroxysmal nocturnal hemoglobinuria (PNH). The binding of Hb to glycoprotein1bα (GP1bα) increases platelet activation. A peptide AA1-50, designed from N-terminal amino acid sequence of GP1bα significantly inhibits the Hb binding to GP1bα as well as Hb-induced platelet activation. This study further examined if the Hb-mediated platelet activation plays any significant role in thrombus formation on subendothelium matrix under physiological flow shear stresses and the inhibition of Hb-platelet interaction can abrogate the above effects of Hb. Study performed thrombus formation assay in vitro by perfusing whole blood over immobilized VWF or collagen type I in presence of Hb under shear stresses simulating arterial or venous flow. The Hb concentrations ranging from 5 to 10 μM, commonly observed level in plasma of the hemolytic patients including PNH, dose-dependently increased thrombus formation on immobilized VWF under higher shear stress of 25 dyne/cm2, but not at 5 dyne/cm2. The above Hb concentrations also increased thrombus formation on immobilized collagen under both shear stresses of 5 and 25 dyne/cm2. The peptide AA1-50 abrogated invariably the above effects of Hb on thrombus formation. This study therefore indicates that the Hb-induced platelet activation plays a crucial role in thrombus formation on immobilized VWF or collagen under physiological flow shear stresses. Thus suggesting a probable role of this mechanism in facilitating thrombosis under hemolytic conditions.
-
Sugita, Chihiro; Yamashita, Atsushi; Matsuura, Yunosuke; Iwakiri, Takashi; Okuyama, Nozomi; Matsuda, Shuntaro; Matsumoto, Tomoko; Inoue, Osamu; Harada, Aya; Kitazawa, Takehisa; Hattori, Kunihiro; Shima, Midori; Asada, Yujiro
2013-07-01
Elevated plasma levels of factor VIII (FVIII) are associated with increased risk of deep venous thrombosis. The aim of this study is to elucidate how elevated FVIII levels affect venous thrombus formation and propagation in vivo. We examined rabbit plasma FVIII activity, plasma thrombin generation, whole blood coagulation, platelet aggregation and venous wall thrombogenicity before and one hour after an intravenous infusion of recombinant human FVIII (rFVIII). Venous thrombus induced by the endothelial denudation of rabbit jugular veins was histologically assessed. Thrombus propagation was evaluated as indocyanine green fluorescence intensity. Argatroban, a thrombin inhibitor, and neutralised antibodies for tissue factor (TF), factor XI (FXI), and von Willebrand factor (VWF) were infused before or after thrombus induction to investigate their effects on venous thrombus formation or propagation. Recombinant FVIII (100 IU/kg) increased rabbit plasma FVIII activity two-fold and significantly enhanced whole blood coagulation and total plasma thrombin generation, but did not affect initial thrombin generation time, platelet aggregation and venous wall thrombogenicity. The rFVIII infusion also increased the size of venous thrombus 1 hour after thrombus induction. Argatroban and the antibodies for TF, FXI or VWF inhibited such enhanced thrombus formation and all except TF suppressed thrombus propagation. In conclusion, elevated plasma FVIII levels enhance venous thrombus formation and propagation. Excess thrombin generation by FXI and VWF-mediated FVIII recruitment appear to contribute to the growth of FVIII-driven venous thrombus.
-
International Nuclear Information System (INIS)
Cadroy, Y.; Horbett, T.A.; Hanson, S.R.
1989-01-01
To study mechanisms of complex thrombus formation in vivo, and to compare the relative antithrombotic effects of anticoagulants and antiplatelet agents, a model was developed in baboons. Segments of collagen-coated tubing followed by two sequentially placed expansion chambers exhibiting disturbed flow patterns were exposed to native blood under laminar flow conditions. The device was incorporated for 1 hour into an exteriorized arteriovenous shunt in baboons under controlled blood flow (20 ml/min). Morphologic evaluation by scanning electron microscopy showed that thrombi associated with collagen were relatively rich in platelets but thrombi in the chambers were rich in fibrin and red cells. Deposition of indium 111-labeled platelets was continuously measured with a scintillation camera. Platelet deposition increased in a linear (collagen-coated segment) or exponential (chambers 1 and 2) fashion over time, with values after 40 minutes averaging 24.1 +/- 3.3 x 10(8) platelets (collagen segment), 16.7 +/- 3.4 x 10(8) platelets (chamber 1), and 8.4 +/- 2.4 x 10(8) platelets (chamber 2). Total fibrinogen deposition after 40 minutes was determined by using iodine 125-labeled baboon fibrinogen and averaged 0.58 +/- 0.14 mg in the collagen segment, 1.51 +/- 0.27 mg in chamber 1, and 0.95 +/- 0.25 mg in chamber 2. Plasma levels of beta-thromboglobulin (beta TG), platelet-factor 4 (PF4), and fibrinopeptide A (FPA) increased fourfold to fivefold after 60 minutes of blood exposure to the thrombotic device. Platelet deposition onto the collagen segment, chamber 1, and chamber 2 was linearly dependent on the circulating platelet count. Platelet accumulation in chamber 1 and chamber 2 was also dependent on the presence of the proximal collagen segment
-
Multi-parameter assessment of thrombus formation on microspotted arrays of thrombogenic surfaces
sprotocols
2014-01-01
Authors: Susanne de Witt, Frauke Swieringa, Judith Cosemans & Johan Heemskerk ### Abstract Thrombus formation by adhering and aggregating blood platelets is fundamental to hemostasis and is a prerequisite for vascular occlusion in pathological thrombosis. The parallel-plate flow chamber technique has been extensively used to measure platelet adhesion and activation in vitro at arterial or venous flow conditions. Here, we describe the use of brightfield and confocal fluorescence micros...
-
Nattokinase improves blood flow by inhibiting platelet aggregation and thrombus formation
Jang, Ja-Young; Kim, Tae-Su; Cai, Jingmei; Kim, Jihyun; Kim, Youngeun; Shin, Kyungha; Kim, Kwang Sei; Park, Sung Kyeong; Lee, Sung-Pyo; Choi, Ehn-Kyoung; Rhee, Man Hee; Kim, Yun-Bae
2013-01-01
The effects of nattokinase on the in vitro platelet aggregation and in vivo thrombosis were investigated in comparison with aspirin. Rabbit platelet-rich plasma was incubated with nattokinase and aggregation inducers collagen and thrombin, and the platelet aggregation rate was analyzed. Nattokinase significantly inhibited both the collagen- and thrombin-induced platelet aggregations. Nattokinase also reduced thromboxane B2 formation from collagen-activated platelets in a concentration-depende...
-
Directory of Open Access Journals (Sweden)
Suying Dang
Full Text Available Most antithrombotic approaches target prevention rather than the more clinically relevant issue of resolution of an existing thrombus. In this study, we describe a novel and effective therapeutic strategy for ex vivo clearance of pre-existing platelet thrombus by the combination of two bifunctional platelet GPIIIa49-66 ligands that target different parts of the arterial thrombus. We produced an additional GPIIIa49-66 agent (named APAC, which homes to activated platelets. Like our previously described SLK (which targets newly deposited fibrin strands surrounding the platelet thrombus, APAC destroys platelet aggregates ex vivo in an identical fashion with 85% destruction of platelet aggregates at 2 hours. The combined application of APAC and SLK demonstrated a ~2 fold greater platelet thrombus dissolution than either agent alone at a low concentration (0.025 µM. Platelet-rich clot lysis experiments demonstrated the time required for 50% platelet-rich fibrin clot lysis (T(50% by APAC (95 ± 6.1 min or SLK (145 ± 7.1 min was much longer than that by combined APAC + SLK (65 ± 7.6 min at the final concentration of 0.025 µM (APAC + SLK vs APAC, p<0.05; APAC + SLK vs SLK, p<0.01. Thus these low concentrations of a combination of both agents are likely to be more effective and less toxic when used therapeutically in vivo.
-
Brandt, Moritz; Schönfelder, Tanja; Schwenk, Melanie; Becker, Christian; Jäckel, Sven; Reinhardt, Christoph; Stark, Konstantin; Massberg, Steffen; Münzel, Thomas; von Brühl, Marie-Luise; Wenzel, Philip
2014-01-01
Interaction between vascular wall abnormalities, inflammatory leukocytes, platelets, coagulation factors and hemorheology in the pathogenesis of deep vein thrombosis (DVT) is incompletely understood, requiring well defined animal models of human disease. We subjected male C57BL/6 mice to ligation of the inferior vena cava (IVC) as a flow reduction model to induce DVT. Thrombus size and weight were analyzed macroscopically and sonographically by B-mode, pulse wave (pw) Doppler and power Doppler imaging (PDI) using high frequency ultrasound. Thrombus size varied substantially between individual procedures and mice, irrespective of the flow reduction achieved by the ligature. Interestingly, PDI accurately predicted thrombus size in a very robust fashion (r2 = 0.9734, p thrombus weight (r2 = 0.5597, p thrombus formation. Occlusion of side branches prior to ligation of IVC did not increase thrombus size, probably due to patent side branches inaccessible to surgery. Venous side branches influence thrombus size in experimental DVT and might therefore prevent thrombus formation. This renders vessel anatomy and hemorheology important determinants in mouse models of DVT, which should be controlled for.
-
Platelet thrombosis in cardiac-valve prostheses
International Nuclear Information System (INIS)
Dewanjee, M.K.
1989-01-01
The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day study in the dog model was similar (< 1% if injected In-111 platelets = 5 billion platelets). As the fibrous ingrowth covered the sewing ring, the thrombus formation decreased significantly. Only a small amount of thrombus was found on the leaflets at one month in both the dog and calf models. 38 refs., 9 figs., 5 tabs
-
Platelet thrombosis in cardiac-valve prostheses
Energy Technology Data Exchange (ETDEWEB)
Dewanjee, M.K.
1989-01-01
The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day study in the dog model was similar (< 1% if injected In-111 platelets = 5 billion platelets). As the fibrous ingrowth covered the sewing ring, the thrombus formation decreased significantly. Only a small amount of thrombus was found on the leaflets at one month in both the dog and calf models. 38 refs., 9 figs., 5 tabs.
-
Use of an anti-platelet monoclonal antibody F (ab')2 fragment for imaging thrombus
International Nuclear Information System (INIS)
Loutfi, I.; Stuttle, A.W.J.; Peters, A.M.; George, P.; Lavender, J.P.; Lumley, P.
1990-01-01
Ten patients with suspected thrombus have been studied using 111 In-labelled F (ab')2 fragments of P256, a monoclonal antibody which recognizes an epitope on the platelet membrane glycoprotein IIb/IIIa complex. The F (ab')2 fragment was radiolabelled with 111 In via diethylenetri-aminepentamacetic acid to give a specific activity of up to 190 MBq (5mCi) mg - 1 without impairment of immunoreactivity. In vitro platelet aggregation studies showed that the F (ab')2 fragment caused less platelet aggregation than the whole antibody on a molar ratio and was without significant effect upon the sensitivity of platelets to a range of aggregating agents. Platalets were labelled in ten patients by intravenous injection of approximately 100 μg P256 F (ab')2. Of the ten patients studies, six showed localization of activity consistent with platelet accumulation. Localization was clearly seen when associated with thrombus of the lower limbs (three patients: deep vein thrombosis; one patient: aortofemoral graft), and was apparent although less marked in two other cases, one of aortic aneurysm and one of carotid stenosis. Use of radiolabelled P256 F (ab')2 offers a means of non-invasive detection of thrombus which, from in vitro studies, would appear to have less direct effect of platelet behaviour than the whole antibody. (author). 9 refs. 8 figs. 1 tab
-
Nattokinase improves blood flow by inhibiting platelet aggregation and thrombus formation.
Jang, Ja-Young; Kim, Tae-Su; Cai, Jingmei; Kim, Jihyun; Kim, Youngeun; Shin, Kyungha; Kim, Kwang Sei; Park, Sung Kyeong; Lee, Sung-Pyo; Choi, Ehn-Kyoung; Rhee, Man Hee; Kim, Yun-Bae
2013-12-01
The effects of nattokinase on the in vitro platelet aggregation and in vivo thrombosis were investigated in comparison with aspirin. Rabbit platelet-rich plasma was incubated with nattokinase and aggregation inducers collagen and thrombin, and the platelet aggregation rate was analyzed. Nattokinase significantly inhibited both the collagen- and thrombin-induced platelet aggregations. Nattokinase also reduced thromboxane B2 formation from collagen-activated platelets in a concentration-dependent manner. Rats were orally administered with nattokinase for 1 week, and their carotid arteries were exposed. Arterial thrombosis was induced by applying 35% FeCl3-soaked filter paper for 10 min, and the blood flow was monitored with a laser Doppler probe. Nattokinase delayed the FeCl3-induced arterial occlusion in a dose-dependent manner, doubling the occlusion time at 160 mg/kg. In addition, a high dose (500 mg/kg) of nattokinase fully prevented the occlusion, as achieved with aspirin (30 mg/kg). The results indicate that nattokinase extracted from fermented soybean inhibit platelet aggregation by blocking thromboxane formation, and thereby delay thrombosis following oxidative arterial wall injury. Therefore, it is suggested that nattokinase could be a good candidate without adverse effects for the improvement of blood flow.
-
International Nuclear Information System (INIS)
Palabrica, T.M.; Furie, B.C.; Konstam, M.A.; Aronovitz, M.J.; Connolly, R.; Brockway, B.A.; Ramberg, K.L.; Furie, B.
1989-01-01
The activated platelet is a potential target for the localization of thrombi in vivo since, after stimulation and secretion of granule contents, activated platelets are concentrated at sites of blood clot formation. In this study, we used antibodies specific for a membrane protein of activated platelets to detect experimental thrombi in an animal model. PADGEM (platelet activation-dependent granule-external membrane protein), a platelet alpha-granule membrane protein, is translocated to the plasma membrane during platelet activation and granule secretion. Since PADGEM is internal in unstimulated platelets, polyclonal anti-PADGEM and monoclonal KC4 antibodies do not bind to circulating resting platelets but do interact with activated platelets. Dacron graft material incubated with radiolabeled KC4 or anti-PADGEM antibodies in the presence of thrombin-activated platelet-rich plasma bound most of the antibody. Imaging experiments with 123I-labeled anti-PADGEM in baboons with an external arterial-venous Dacron shunt revealed rapid uptake in the thrombus induced by the Dacron graft; control experiments with 123I-labeled nonimmune IgG exhibited minimal uptake. Deep venous thrombi, formed by using percutaneous balloon catheters to stop blood flow in the femoral vein of baboons, were visualized with 123I-labeled anti-PADGEM. Thrombi were discernible against blood pool background activity without subtraction techniques within 1 hr. No target enhancement was seen with 123I-labeled nonimmune IgG. 123I-labeled anti-PADGEM cleared the blood pool with an initial half-disappearance time of 6 min and did not interfere with hemostasis. These results indicate that radioimmunoscintigraphy with anti-PADGEM antibodies can visualize thrombi in baboon models and is a promising technique for clinical thrombus detection in humans
-
Lehmann, Marcus; Schoeman, Rogier M; Krohl, Patrick J; Wallbank, Alison M; Samaniuk, Joseph R; Jandrot-Perrus, Martine; Neeves, Keith B
2018-05-01
The objective of this study was to measure the role of platelets and red blood cells on thrombus propagation in an in vitro model of venous valvular stasis. A microfluidic model with dimensional similarity to human venous valves consists of a sinus distal to a sudden expansion, where for sufficiently high Reynolds numbers, 2 countercurrent vortices arise because of flow separation. The primary vortex is defined by the points of flow separation and reattachment. A secondary vortex forms in the deepest recess of the valve pocket characterized by low shear rates. An initial fibrin gel formed within the secondary vortex of a tissue factor-coated valve sinus. Platelets accumulated at the interface of the fibrin gel and the primary vortex. Red blood cells at physiological hematocrits were necessary to provide an adequate flux of platelets to support thrombus growth out of the valve sinus. A subpopulation of platelets that adhered to fibrin expose phosphatidylserine. Platelet-dependent thrombus growth was attenuated by inhibition of glycoprotein VI with a blocking Fab fragment or D-dimer. A 3-step process regulated by hemodynamics was necessary for robust thrombus propagation: First, immobilized tissue factor initiates coagulation and fibrin deposition within a low flow niche defined by a secondary vortex in the pocket of a model venous valve. Second, a primary vortex delivers platelets to the fibrin interface in a red blood cell-dependent manner. Third, platelets adhere to fibrin, activate through glycoprotein VI, express phosphatidylserine, and subsequently promote thrombus growth beyond the valve sinus and into the bulk flow. © 2018 American Heart Association, Inc.
-
Dynamics of blood flow and thrombus formation in a multi-bypass microfluidic ladder network.
Zilberman-Rudenko, Jevgenia; Sylman, Joanna L; Lakshmanan, Hari H S; McCarty, Owen J T; Maddala, Jeevan
2017-02-01
The reaction dynamics of a complex mixture of cells and proteins, such as blood, in branched circulatory networks within the human microvasculature or extravascular therapeutic devices such as extracorporeal oxygenation machine (ECMO) remains ill-defined. In this report we utilize a multi-bypass microfluidics ladder network design with dimensions mimicking venules to study patterns of blood platelet aggregation and fibrin formation under complex shear. Complex blood fluid dynamics within multi-bypass networks under flow were modeled using COMSOL. Red blood cells and platelets were assumed to be non-interacting spherical particles transported by the bulk fluid flow, and convection of the activated coagulation factor II, thrombin, was assumed to be governed by mass transfer. This model served as the basis for predicting formation of local shear rate gradients, stagnation points and recirculation zones as dictated by the bypass geometry. Based on the insights from these models, we were able to predict the patterns of blood clot formation at specific locations in the device. Our experimental data was then used to adjust the model to account for the dynamical presence of thrombus formation in the biorheology of blood flow. The model predictions were then compared to results from experiments using recalcified whole human blood. Microfluidic devices were coated with the extracellular matrix protein, fibrillar collagen, and the initiator of the extrinsic pathway of coagulation, tissue factor. Blood was perfused through the devices at a flow rate of 2 µL/min, translating to physiologically relevant initial shear rates of 300 and 700 s -1 for main channels and bypasses, respectively. Using fluorescent and light microscopy, we observed distinct flow and thrombus formation patterns near channel intersections at bypass points, within recirculation zones and at stagnation points. Findings from this proof-of-principle ladder network model suggest a specific correlation between
-
Vascular Nitric Oxide-Superoxide Balance and Thrombus Formation after Acute Exercise.
Przyborowski, Kamil; Proniewski, Bartosz; Czarny, Joanna; Smeda, Marta; Sitek, Barbara; Zakrzewska, Agnieszka; Zoladz, Jerzy A; Chlopicki, Stefan
2018-02-21
An acute bout of strenuous exercise in humans results in transient impairment of NO-dependent function, but it remains unknown whether this phenomenon is associated with increased risk of post-exercise thrombotic events. This study aimed to evaluate effects of a single bout of exhaustive running in mice on the balance of vascular nitric oxide (NO)/reactive oxygen species (ROS) production, and on thrombogenicity. At different time-points (0h, 2h and 4h) after exercise and in sedentary C57BL/6 mice the production of NO and superoxide (O2) in aorta was measured by electron paramagnetic resonance (EPR) spin trapping and by dihydroethidium (DHE)/HPLC-based method, respectively, while collagen-induced thrombus formation was analyzed in a microchip-based flow-chamber system (T-TAS). We also measured pre- and post-exercise plasma concentration of nitrite/nitrate and 6-keto-PGF1α. An acute bout of exhaustive running in mice resulted in decreased production of NO and increased production of O2 in aorta, with maximum changes 2h after completion of exercise when compared to sedentary mice. However, platelet thrombus formation was not changed by exercise as evidenced by unaltered time to start of thrombus formation (T10) and capillary occlusion (OT), and total thrombogenicity (AUC) as measured in a flow-chamber system. Strenuous exercise increased the plasma concentration of nitrite but did not affect nitrate and 6-keto-PGF1α concentrations. An acute bout of strenuous exercise in mice reduced NO and in parallel increased O2 production in aorta. This response was most pronounced 2h after exercise. Surprisingly, the reduced NO and increased O2 production did not result in increased post-exercise platelet-dependent thrombogenicity. These results show that transient reduction in NO bioavailability, caused by exercise-induced oxidative stress, does not modify post-exercise thromboresistance in healthy mice.
-
Bye, Alexander P; Unsworth, Amanda J; Vaiyapuri, Sakthivel; Stainer, Alexander R; Fry, Michael J; Gibbins, Jonathan M
2015-11-01
Ibrutinib is an irreversible Bruton tyrosine kinase inhibitor approved for treatment of Waldenstrom macroglobulinemia, chronic lymphocytic leukemia, and mantle cell lymphoma that increases the risk of bleeding among patients. Platelets from ibrutinib-treated patients exhibit deficiencies in collagen-evoked signaling in suspension; however, the significance of this observation and how it relates to bleeding risk is unclear, as platelets encounter immobile collagen in vivo. We sought to clarify the effects of ibrutinib on platelet function to better understand the mechanism underlying bleeding risk. By comparing signaling in suspension and during adhesion to immobilized ligands, we found that the collagen signaling deficiency caused by ibrutinib is milder during adhesion to immobilized collagen. We also found that platelets in whole blood treated with ibrutinib adhered to collagen under arterial shear but formed unstable thrombi, suggesting that the collagen signaling deficiency caused by ibrutinib may not be the predominant cause of bleeding in vivo. However, clot retraction and signaling evoked by platelet adhesion to immobilized fibrinogen were also inhibited by ibrutinib, indicating that integrin αIIbβ3 outside-in signaling is also effected in addition to GPVI signaling. When ibrutinib was combined with the P2Y12 inhibitor, cangrelor, thrombus formation under arterial shear was inhibited additively. These findings suggest that (1) ibrutinib causes GPVI and integrin αIIbβ3 platelet signaling deficiencies that result in formation of unstable thrombi and may contribute toward bleeding observed in vivo and (2) combining ibrutinib with P2Y12 antagonists, which also inhibit thrombus stability, may have a detrimental effect on hemostasis. © 2015 American Heart Association, Inc.
-
Analysis of early thrombus dynamics in a humanized mouse laser injury model.
Wang, Weiwei; Lindsey, John P; Chen, Jianchun; Diacovo, Thomas G; King, Michael R
2014-01-01
Platelet aggregation and thrombus formation at the site of injury is a dynamic process that involves the continuous addition of new platelets as well as thrombus rupture. In the early stages of hemostasis (within minutes after vessel injury) this process can be visualized by transfusing fluorescently labeled human platelets and observing their deposition and detachment. These two counterbalancing events help the developing thrombus reach a steady-state morphology, where it is large enough to cover the injured vessel surface but not too large to form a severe thrombotic occlusion. In this study, the spatial and temporal aspects of early stage thrombus dynamics which result from laser-induced injury on arterioles of cremaster muscle in the humanized mouse were visualized using fluorescent microscopy. It was found that rolling platelets show preference for the upstream region while tethering/detaching platelets were primarily found downstream. It was also determined that the platelet deposition rate is relatively steady, whereas the effective thrombus coverage area does not increase at a constant rate. By introducing a new method to graphically represent the real time in vivo physiological shear stress environment, we conclude that the thrombus continuously changes shape by regional growth and decay, and neither dominates in the high shear stress region.
-
Energy Technology Data Exchange (ETDEWEB)
Takeda, T; Ishikawa, N; Satoh, A; Masuda, Y; Hiramatsu, Y; Akisada, M; Sakakibara, Y
1985-07-01
A 54-year-old man was admitted to hospital with a 3-month history of progressive dyspnea with coughing. A giant right atrial mass, originating from a hepatocellular carcinoma, was visualized by computed tomography, and digital subtraction angiography. The volume if the right atrial mass was increasing rapidly. It was therefore essential to determine whether this giant mass was a tumor thrombus or a multiplication of the hepatocellular carcinoma. /sup 111/In-oxine labeled platelet scintigraphy revealed active accumulation in the right atrium caused by the presence of active platelet deposition, and slight accumulation in the lung fields probably due to embolic showers originating from the tumor thrombus in the right atrium. This is the first case report showing that /sup 111/In-oxine labeled platelet scintigraphy can aid in confirming the nature of a giant tumor thrombus in the right atrium and can clarify the pathogenesis of the respiratory symptoms.
-
Budnik, Ivan; Shenkman, Boris; Savion, Naphtali
2015-01-01
Thrombus formation in the injured vessel wall is a highly complex process involving various blood-born components that go through specific temporal and spatial changes as observed by intravital videomicroscopy. Platelets bind transiently to the developing thrombus and may either become stably incorporated into or disengage from the thrombus. The aim of the present study was to reveal the processes involved in the formation of a stable thrombus. Platelet-rich plasma and washed platelets were studied by the aggregometer. The aggregate stability was challenged by eptifibatide. Platelet Triton-insoluble fraction was prepared and the actin and αIIb content in the cytoskeleton was analyzed by western blot. Maximal actin polymerization is achieved 1min after platelet activation while maximal αIIbβ3-actin cytoskeleton association requires 5 to 10min of activation and fibrinogen-mediated platelet-to-platelet bridging. Thus, actin polymerization is dependent on platelet activation and requires neither αIIbβ3 integrin occupation nor platelet aggregation. Formation of a stable aggregate requires platelet activation for more than 1min, complete increase in actin cytoskeleton fraction and partial association of αIIbβ3 with the actin cytoskeleton. However, direct αIIbβ3 activation is not sufficient for cytoskeleton complex formation. Thus, stable αIIbβ3-fibrinogen interaction, representing stable aggregate, is achieved after more than 1min agonist activation, involving inside-out and outside-in signaling but not after direct integrin activation, involving only outside-in signaling. Formation of a stable fibrinogen-αIIbβ3-actin cytoskeleton complex is the result of the combined effect of platelet stimulation by soluble agonists, activation of αIIbβ3, fibrinogen binding and platelet-to-platelet bridging. Copyright © 2014 Elsevier Ltd. All rights reserved.
-
An investigation on platelet transport during thrombus formation at micro-scale stenosis.
Directory of Open Access Journals (Sweden)
Francisco Javier Tovar-Lopez
Full Text Available This paper reports on an investigation of mass transport of blood cells at micro-scale stenosis where local strain-rate micro-gradients trigger platelet aggregation. Using a microfluidic flow focusing platform we investigate the blood flow streams that principally contribute to platelet aggregation under shear micro-gradient conditions. We demonstrate that relatively thin surface streams located at the channel wall are the primary contributor of platelets to the developing aggregate under shear gradient conditions. Furthermore we delineate a role for red blood cell hydrodynamic lift forces in driving enhanced advection of platelets to the stenosis wall and surface of developing aggregates. We show that this novel microfluidic platform can be effectively used to study the role of mass transport phenomena driving platelet recruitment and aggregate formation and believe that this approach will lead to a greater understanding of the mechanisms underlying shear-gradient dependent discoid platelet aggregation in the context of cardiovascular diseases such as acute coronary syndromes and ischemic stroke.
-
International Nuclear Information System (INIS)
Seabold, J.E.; Schroeder, E.C.; Conrad, G.R.
1987-01-01
Two-dimensional echocardiography and indium-111 platelet scintigraphy were performed on 50 dogs to determine the influence of clot age and size on the detection of experimentally induced left ventricular mural thrombus. Thrombus was induced by apical infarction and injection of a sclerosing agent and thrombin. The animals were classified into four groups according to the time of indium-111 platelet injection after thrombus induction: Group I (17 dogs, 1/2 hour after induction; 3 dogs, before induction), Group II (12 dogs, 24 hours after induction) and Group III (12 dogs, 1 week after induction). In Group IV (six control dogs) apical infarction was produced, but thrombin was not injected; indium-111 platelets were injected 1/2 to 1 hour after infarction. The dogs were studied by indium-111 platelet scintigraphy and by two-dimensional echocardiography 1/2 to 5 hours (Group I) and 1 to 5 and up to 72 hours (Groups II to IV) after platelet administration and before death was induced. Two-dimensional echocardiography showed the best overall sensitivity for detection of acute thrombus (97%; 29 of 30). The sensitivity of indium-111 platelet scintigraphy was 86% (18 of 21) for clots greater than or equal to 0.08 ml in size, and 67% (20 of 30) for detection of all clots. Thrombus did not form in 14 dogs of Groups I to III and in 6 of 6 control dogs. The specificity of scintigraphy was 100% (20 of 20) compared with 80% (16 of 20) for echocardiography. Echocardiography was more sensitive than scintigraphy for detecting very small clots in this experimental model
-
Thioredoxin Inhibitors Attenuate Platelet Function and Thrombus Formation.
Metcalfe, Clive; Ramasubramoni, Anjana; Pula, Giordano; Harper, Matthew T; Mundell, Stuart J; Coxon, Carmen H
2016-01-01
Thioredoxin (Trx) is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for haemostasis and the current interest in developing inhibitors for clinical use, we thought it pertinent to assess whether inhibition of the NADPH/thioredoxin reductase/thioredoxin system affects platelet function and thrombosis. We used small molecule inhibitors of Trx (PMX 464 and PX-12) to determine whether Trx activity influences platelet function, as well as an unbiased proteomics approach to identify potential Trx substrates on the surface of platelets that might contribute to platelet reactivity and function. Using LC-MS/MS we found that PMX 464 and PX-12 affected the oxidation state of thiols in a number of cell surface proteins. Key surface receptors for platelet adhesion and activation were affected, including the collagen receptor GPVI and the von Willebrand factor receptor, GPIb. To experimentally validate these findings we assessed platelet function in the presence of PMX 464, PX-12, and rutin (a selective inhibitor of the related protein disulphide isomerase). In agreement with the proteomics data, small molecule inhibitors of thioredoxin selectively inhibited GPVI-mediated platelet activation, and attenuated ristocetin-induced GPIb-vWF-mediated platelet agglutination, thus validating the findings of the proteomics study. These data reveal a novel role for thioredoxin in regulating platelet reactivity via proteins required for early platelet responses at sites of vessel injury (GPVI and GPIb). This work also highlights a potential opportunity for repurposing of PMX 464 and PX-12 as antiplatelet agents.
-
Thioredoxin Inhibitors Attenuate Platelet Function and Thrombus Formation.
Directory of Open Access Journals (Sweden)
Clive Metcalfe
Full Text Available Thioredoxin (Trx is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for haemostasis and the current interest in developing inhibitors for clinical use, we thought it pertinent to assess whether inhibition of the NADPH/thioredoxin reductase/thioredoxin system affects platelet function and thrombosis. We used small molecule inhibitors of Trx (PMX 464 and PX-12 to determine whether Trx activity influences platelet function, as well as an unbiased proteomics approach to identify potential Trx substrates on the surface of platelets that might contribute to platelet reactivity and function. Using LC-MS/MS we found that PMX 464 and PX-12 affected the oxidation state of thiols in a number of cell surface proteins. Key surface receptors for platelet adhesion and activation were affected, including the collagen receptor GPVI and the von Willebrand factor receptor, GPIb. To experimentally validate these findings we assessed platelet function in the presence of PMX 464, PX-12, and rutin (a selective inhibitor of the related protein disulphide isomerase. In agreement with the proteomics data, small molecule inhibitors of thioredoxin selectively inhibited GPVI-mediated platelet activation, and attenuated ristocetin-induced GPIb-vWF-mediated platelet agglutination, thus validating the findings of the proteomics study. These data reveal a novel role for thioredoxin in regulating platelet reactivity via proteins required for early platelet responses at sites of vessel injury (GPVI and GPIb. This work also highlights a potential opportunity for repurposing of PMX 464 and PX-12 as antiplatelet agents.
-
Vessel wall and indium-111-labelled platelet response to carotid endarterectomy
International Nuclear Information System (INIS)
Lusby, R.J.; Ferrell, L.D.; Englestad, B.L.; Price, D.C.; Lipton, M.J.; Stoney, R.J.
1983-01-01
Postendarterectomy platelet deposition and thrombus formation may play an important role not only in vessel wall healing but also in the small incidence of postoperative cerebral ischemia and postoperative stenosis. A study has been performed using a canine model to investigate the healing response to carotid endarterectomy and the validity of an in vivo indium-111 (In-111) radiotracer technique in the assessment of postendarterectomy deposition of autologous labelled platelets. Sixteen endarterectomized carotid arteries showed uptake of autologous In-111 platelets immediately after infusion, reaching a maximum by 1 hour with little increase at 24 or 48 hours. No uptake was seen in ten control vessels following platelet infusion (P less than 0.05). At autopsy, seven vessels were demonstrated to have In-111 platelet deposition immediately prior to sacrifice of the animals. Postmortem scanning confirmed the localization to the vessel lumens, and microscopy revealed thrombus formation with or without partial endothelialization. Complete reendothelialization had occurred in the vessels that failed to show platelet deposition. Delayed healing was associated with continuing platelet deposition, excessive thrombus formation, and luminal stenosis. Arteriotomy closure with a vein patch altered the healing characteristics of the vessel with segmental thrombus formation over the vein patch. A preliminary study of the postendarterectomy in vivo In-111 platelet response in humans demonstrated platelet deposition that was not influenced by the administration of antiplatelet drugs at currently prescribed levels
-
The role of platelet and endothelial GARP in thrombosis and hemostasis.
Vermeersch, Elien; Denorme, Frederik; Maes, Wim; De Meyer, Simon F; Vanhoorelbeke, Karen; Edwards, Justin; Shevach, Ethan M; Unutmaz, Derya; Fujii, Hodaka; Deckmyn, Hans; Tersteeg, Claudia
2017-01-01
Glycoprotein-A Repetitions Predominant protein (GARP or LRRC32) is present on among others human platelets and endothelial cells. Evidence for its involvement in thrombus formation was suggested by full knockout of GARP in zebrafish. To evaluate the role of GARP in platelet physiology and in thrombus formation using platelet and endothelial conditional GARP knock out mice. Platelet and endothelial specific GARP knockout mice were generated using the Cre-loxP recombination system. The function of platelets without GARP was measured by flow cytometry, spreading analysis and aggregometry using PAR4-activating peptide and collagen related peptide. Additionally, clot retraction and collagen-induced platelet adhesion and aggregation under flow were analyzed. Finally, in vivo tail bleeding time, occlusion time of the mesenteric and carotid artery after FeCl3-induced thrombosis were determined in platelet and endothelial specific GARP knock out mice. Platelet specific GARP knockout mice had normal surface GPIb, GPVI and integrin αIIb glycoprotein expression. Although GARP expression was increased upon platelet activation, platelets without GARP displayed normal agonist induced activation, spreading on fibrinogen and aggregation responses. Furthermore, absence of GARP on platelets did not influence clot retraction and had no impact on thrombus formation on collagen-coated surfaces under flow. In line with this, neither the tail bleeding time nor the occlusion time in the carotid- and mesenteric artery after FeCl3-induced thrombus formation in platelet or endothelial specific GARP knock out mice were affected. Evidence is provided that platelet and endothelial GARP are not important in hemostasis and thrombosis in mice.
-
The role of platelet and endothelial GARP in thrombosis and hemostasis.
Directory of Open Access Journals (Sweden)
Elien Vermeersch
Full Text Available Glycoprotein-A Repetitions Predominant protein (GARP or LRRC32 is present on among others human platelets and endothelial cells. Evidence for its involvement in thrombus formation was suggested by full knockout of GARP in zebrafish.To evaluate the role of GARP in platelet physiology and in thrombus formation using platelet and endothelial conditional GARP knock out mice.Platelet and endothelial specific GARP knockout mice were generated using the Cre-loxP recombination system. The function of platelets without GARP was measured by flow cytometry, spreading analysis and aggregometry using PAR4-activating peptide and collagen related peptide. Additionally, clot retraction and collagen-induced platelet adhesion and aggregation under flow were analyzed. Finally, in vivo tail bleeding time, occlusion time of the mesenteric and carotid artery after FeCl3-induced thrombosis were determined in platelet and endothelial specific GARP knock out mice.Platelet specific GARP knockout mice had normal surface GPIb, GPVI and integrin αIIb glycoprotein expression. Although GARP expression was increased upon platelet activation, platelets without GARP displayed normal agonist induced activation, spreading on fibrinogen and aggregation responses. Furthermore, absence of GARP on platelets did not influence clot retraction and had no impact on thrombus formation on collagen-coated surfaces under flow. In line with this, neither the tail bleeding time nor the occlusion time in the carotid- and mesenteric artery after FeCl3-induced thrombus formation in platelet or endothelial specific GARP knock out mice were affected.Evidence is provided that platelet and endothelial GARP are not important in hemostasis and thrombosis in mice.
-
Directory of Open Access Journals (Sweden)
Abimbola A Onasoga-Jarvis
Full Text Available Clinical evidence suggests that individuals with factor VIII (FVIII deficiency (hemophilia A are protected against venous thrombosis, but treatment with recombinant proteins can increase their risk for thrombosis. In this study we examined the dynamics of thrombus formation in individuals with hemophilia A and their response to replacement and bypass therapies under venous flow conditions. Fibrin and platelet accumulation were measured in microfluidic flow assays on a TF-rich surface at a shear rate of 100 s⁻¹. Thrombin generation was calculated with a computational spatial-temporal model of thrombus formation. Mild FVIII deficiencies (5-30% normal levels could support fibrin fiber formation, while severe (1 nM, but too low to support fibrin formation (<10 nM. In the absence of platelets, fibrin formation was not supported even at normal FVIII levels, suggesting platelet adhesion is necessary for fibrin formation. Individuals treated by replacement therapy, recombinant FVIII, showed normalized fibrin formation. Individuals treated with bypass therapy, recombinant FVIIa, had a reduced lag time in fibrin formation, as well as elevated fibrin accumulation compared to healthy controls. Treatment of rFVIIa, but not rFVIII, resulted in significant changes in fibrin dynamics that could lead to a prothrombotic state.
-
White thrombus formation in blood tubing lines in a chronic hemodialysis unit.
Watnick, Suzanne; Stooksbury, Michael; Winter, Rolf; Riscoe, Michael; Cohen, David M
2008-03-01
Previous reports have described white particulate matter in banked blood components, but no prior public reports describe such matter in blood tubing during the course of routine in-center hemodialysis. This report describes the events, investigations, and preliminary conclusions associated with the spontaneous formation of adherent white thrombus in the venous and arterial blood lines during routine in-center hemodialysis treatments. Design setting, participants, & measurements: This investigation occurred at the Portland Veterans Administration Medical Center (PVAMC) Hemodialysis Unit from October 2006 through April 2007. Sixty-eight variables regarding demographics, medical history and dialysis treatments were collected on our 34 chronic hemodialysis outpatients. Over a 5-wk interval, 62% (21 of 34) of the chronic hemodialysis patients unexpectedly developed a white precipitate adhering to the lumenal surface of their dialysis blood tubing, with 73 of 580 chronic dialysis treatments exhibiting the phenomenon. Microscopic and biochemical analyses were consistent with white thrombus, formed by an aggregation of platelets and fibrin. An alert was issued and other in-center hemodialysis units noted similar findings. This was remedied by the removal of specific tubing. Both patient-specific and tubing-specific factors may have been operative. Although patient safety was not adversely affected, assessment of clinical and manufacturing variables potentially affecting platelet activation is warranted.
-
Functional genomics in zebrafish permits rapid characterization of novel platelet membrane proteins.
O'Connor, Marie N; Salles, Isabelle I; Cvejic, Ana; Watkins, Nicholas A; Walker, Adam; Garner, Stephen F; Jones, Chris I; Macaulay, Iain C; Steward, Michael; Zwaginga, Jaap-Jan; Bray, Sarah L; Dudbridge, Frank; de Bono, Bernard; Goodall, Alison H; Deckmyn, Hans; Stemple, Derek L; Ouwehand, Willem H
2009-05-07
In this study, we demonstrate the suitability of the vertebrate Danio rerio (zebrafish) for functional screening of novel platelet genes in vivo by reverse genetics. Comparative transcript analysis of platelets and their precursor cell, the megakaryocyte, together with nucleated blood cell elements, endothelial cells, and erythroblasts, identified novel platelet membrane proteins with hitherto unknown roles in thrombus formation. We determined the phenotype induced by antisense morpholino oligonucleotide (MO)-based knockdown of 5 of these genes in a laser-induced arterial thrombosis model. To validate the model, the genes for platelet glycoprotein (GP) IIb and the coagulation protein factor VIII were targeted. MO-injected fish showed normal thrombus initiation but severely impaired thrombus growth, consistent with the mouse knockout phenotypes, and concomitant knockdown of both resulted in spontaneous bleeding. Knockdown of 4 of the 5 novel platelet proteins altered arterial thrombosis, as demonstrated by modified kinetics of thrombus initiation and/or development. We identified a putative role for BAMBI and LRRC32 in promotion and DCBLD2 and ESAM in inhibition of thrombus formation. We conclude that phenotypic analysis of MO-injected zebrafish is a fast and powerful method for initial screening of novel platelet proteins for function in thrombosis.
-
Platelet Glycoprotein Ib-IX and Malignancy
2010-09-01
provide a unique microenvironment supporting the accumulation of more platelets and the elaboration of a fibrin - rich network produced by coagulation...process and can initiate the formation of a platelet - rich thrombus by tethering the platelet to a thrombogenic surface. Several ligands binding to GP Ib... Platelet Glycoprotein Ib-IX and Malignancy PRINCIPAL INVESTIGATOR: Jerry Ware, Ph.D
-
Of von Willebrand factor and platelets.
Bryckaert, Marijke; Rosa, Jean-Philippe; Denis, Cécile V; Lenting, Peter J
2015-01-01
Hemostasis and pathological thrombus formation are dynamic processes that require multiple adhesive receptor-ligand interactions, with blood platelets at the heart of such events. Many studies have contributed to shed light on the importance of von Willebrand factor (VWF) interaction with its platelet receptors, glycoprotein (GP) Ib-IX-V and αIIbβ3 integrin, in promoting primary platelet adhesion and aggregation following vessel injury. This review will recapitulate our current knowledge on the subject from the rheological aspect to the spatio-temporal development of thrombus formation. We will also discuss the signaling events generated by VWF/GPIb-IX-V interaction, leading to platelet activation. Additionally, we will review the growing body of evidence gathered from the recent development of pathological mouse models suggesting that VWF binding to GPIb-IX-V is a promising target in arterial and venous pathological thrombosis. Finally, the pathological aspects of VWF and its impact on platelets will be addressed.
-
Kalia, Neena; Auger, Jocelyn M; Atkinson, Ben; Watson, Steve P
2008-05-01
The role of collagen receptor complex GPVI-FcR gamma-chain, PLCgamma2 and LAT in laser-induced thrombosis is unclear. Controversy surrounds whether collagen is exposed in this model or whether thrombosis is dependent on thrombin. This study hypothesized that collagen exposure plays a critical role in thrombus formation in this model, which was tested by investigating contributions of FcR gamma-chain, LAT, PLCgamma2 and thrombin. Thrombi were monitored using intravital microscopy in anesthetized wild-type and FcR gamma-chain, LAT and PLCgamma2 knockout mice. Hirudin (thrombin inhibitor) was administered to wild-type and FcR gamma-chain knockout mice. Significantly reduced thrombus formation was observed in FcR gamma-chain and PLCgamma2 knockouts with a greater decrease observed in LAT knockouts. Dramatic reduction was observed in wild-types treated with hirudin, with abolished thrombus formation only observed in FcR gamma-chain knockouts treated with hirudin. GPVI-FcR gamma-chain, LAT and PLCgamma2 are essential for thrombus generation and stability in this laser-induced model of injury. More importantly, a greater role for LAT was identified, which may reflect a role for it downstream of a second matrix protein receptor. However, inhibition of platelet activation by matrix proteins and thrombin generation are both required to maximally prevent thrombus formation.
-
Polyphosphate nanoparticles on the platelet surface trigger contact system activation
Verhoef, Johan J F; Barendrecht, Arjan D; Nickel, Katrin F; Dijkxhoorn, Kim; Kenne, Ellinor; Labberton, Linda; McCarty, Owen J T; Schiffelers, Raymond; Heijnen, Harry F G; Hendrickx, Antoni P A; Schellekens, Huub; Fens, Marcel H; de Maat, Steven; Renné, Thomas; Maas, Coen
2017-01-01
Polyphosphate is an inorganic polymer that can potentiate several interactions in the blood coagulation system. Blood platelets contain polyphosphate, and the secretion of platelet-derived polyphosphate has been associated with increased thrombus formation and activation of coagulation factor XII.
-
PLATELET ADHESION TO POLYURETHANE UREA UNDER PULSATILE FLOW CONDITIONS
Navitsky, Michael A.; Taylor, Joshua O.; Smith, Alexander B.; Slattery, Margaret J.; Deutsch, Steven; Siedlecki, Christopher A.; Manning, Keefe B.
2014-01-01
Platelet adhesion to a polyurethane urea surface is a precursor to thrombus formation within blood-contacting cardiovascular devices, and platelets have been found to adhere strongly to polyurethane surfaces below a shear rate of approximately 500 s−1. The aim of the current work is to determine platelet adhesion properties to the polyurethane urea surface as a function of time varying shear exposure. A rotating disk system is used to study the influence of steady and pulsatile flow conditions (e.g. cardiac inflow and sawtooth waveforms) for platelet adhesion to the biomaterial surface. All experiments retain the same root mean square angular rotation velocity (29.63 rad/s) and waveform period. The disk is rotated in platelet rich bovine plasma for two hours with adhesion quantified by confocal microscopy measurements of immunofluorescently labeled bovine platelets. Platelet adhesion under pulsating flow is found to exponentially decay with increasing shear rate. Adhesion levels are found to depend upon peak platelet flux and shear rate regardless of rotational waveform. In combination with flow measurements, these results may be useful for predicting regions susceptible to thrombus formation within ventricular assist devices. PMID:24721222
-
Computational Study of Thrombus Formation and Clotting Factor Effects under Venous Flow Conditions
2016-04-26
domain used in our thrombus formation simulations. Fig. 2 B shows the 3D geometry of the flow-chamber section consisting of two channels measuring 250 60...ArticleComputational Study of Thrombus Formation and Clotting Factor Effects under Venous Flow ConditionsVijay Govindarajan,1 Vineet Rakesh,1 Jaques...understanding of thrombus formation as a physicochemical process that has evolved to protect the integrity of the human vasculature is critical to our ability to
-
Platelet Glycoprotein lb-1X and Malignancy
2011-09-01
initiate coagulation, resulting in the formation of a fibrin - rich tumor cell- platelet emboli (Figure 1). Many of these coagulation factor-tumor cell...the tumor cell in a fibrin - rich web. (13;23;24) During this process, the platelet integrin receptor, aIIb 3, serves as a receptor linking fibrin ... platelets , and tumor cells into a fibrin rich clot normally associated with a thrombus. (25;25) Indeed, it can be speculated the fibrin - rich clot
-
DEFF Research Database (Denmark)
Johansson, Per Ingemar; Svendsen, M.S.; Salado, J.
2008-01-01
thrombin) and endogenous thrombin potential (ETP; nm thrombin*min) were registered. Clot formation was evaluated by TEG and the R time (min), maxial amplitude (MA; mm), time to maximum thrombus generation (TMG; min) and maximum thrombus generation (MTG; dynes cm(-2) s(-1)) and total thrombus generation...... (TTG; dyne cm(-2)) were registered. RESULTS: Platelets become more procoagulant, evaluated both by TEG and CAT during storage. The reduction in CAT lag time and the ttPeak correlated with a decrease in the TEG R time and TMG (P
-
Kuijpers, M. J. E.; Gilio, K.; Reitsma, S.; Nergiz-Unal, R.; Prinzen, L.; Heeneman, S.; Lutgens, E.; van Zandvoort, M. A. M. J.; Nieswandt, B.; Egbrink, M. G. A. Oude; Heemskerk, J. W. M.
2009-01-01
Atherothrombosis is a major cause of cardiovascular events. However, animal models to study this process are scarce. We describe the first murine model of acute thrombus formation upon plaque rupture to study atherothrombosis by intravital fluorescence microscopy. Localized rupture of an
-
Huang, Shiu-Wen; Kuo, Heng-Lan; Hsu, Ming-Tsung; Tseng, Yufeng Jane; Lin, Shu-Wha; Kuo, Sheng-Chu; Peng, Hui-Chin; Lien, Jin-Cherng; Huang, Tur-Fu
2016-08-01
A novel benzimidazole derivative, nstpbp5185, was discovered through in vitro and in vivo evaluations for antiplatelet activity. Thromaboxane receptor (TP) is important in vascular physiology, haemostasis and pathophysiological thrombosis. Nstpbp5185 concentration-dependently inhibited human platelet aggregation caused by collagen, arachidonic acid and U46619. Nstpbp5185 caused a right-shift of the concentration-response curve of U46619 and competitively inhibited the binding of 3H-SQ-29548 to TP receptor expressed on HEK-293 cells, with an IC50 of 0.1 µM, indicating that nstpbp5185 is a TP antagonist. In murine thrombosis models, nstpbp5185 significantly prolonged the latent period in triggering platelet plug formation in mesenteric and FeCl3-induced thrombi formation, and increased the survival rate in pulmonary embolism model with less bleeding than aspirin. This study suggests nstpbp5185, an orally selective anti-thrombotic agent, acting through blockade of TXA2 receptor, may be efficacious for prevention or treatment of pathologic thrombosis.
-
Collagen can selectively trigger a platelet secretory phenotype via glycoprotein VI.
Directory of Open Access Journals (Sweden)
Véronique Ollivier
Full Text Available Platelets are not only central actors of hemostasis and thrombosis but also of other processes including inflammation, angiogenesis, and tissue regeneration. Accumulating evidence indicates that these "non classical" functions of platelets do not necessarily rely on their well-known ability to form thrombi upon activation. This suggests the existence of non-thrombotic alternative states of platelets activation. We investigated this possibility through dose-response analysis of thrombin- and collagen-induced changes in platelet phenotype, with regards to morphological and functional markers of platelet activation including shape change, aggregation, P-selectin and phosphatidylserine surface expression, integrin activation, and release of soluble factors. We show that collagen at low dose (0.25 µg/mL selectively triggers a platelet secretory phenotype characterized by the release of dense- and alpha granule-derived soluble factors without causing any of the other major platelet changes that usually accompany thrombus formation. Using a blocking antibody to glycoprotein VI (GPVI, we further show that this response is mediated by GPVI. Taken together, our results show that platelet activation goes beyond the mechanisms leading to platelet aggregation and also includes alternative platelet phenotypes that might contribute to their thrombus-independent functions.
-
Dual mechanism of integrin αIIbβ3 closure in procoagulant platelets.
Mattheij, Nadine J A; Gilio, Karen; van Kruchten, Roger; Jobe, Shawn M; Wieschhaus, Adam J; Chishti, Athar H; Collins, Peter; Heemskerk, Johan W M; Cosemans, Judith M E M
2013-05-10
Inactivation of integrin αIIbβ3 reverses platelet aggregate formation upon coagulation. Platelets from patient (Scott) and mouse (Capn1(-/-) and Ppif(-/-)) blood reveal a dual mechanism of αIIbβ3 inactivation: by calpain-2 cleavage of integrin-associated proteins and by cyclophilin D/TMEM16F-dependent phospholipid scrambling. These data provide novel insight into the switch mechanisms from aggregating to procoagulant platelets. Aggregation of platelets via activated integrin αIIbβ3 is a prerequisite for thrombus formation. Phosphatidylserine-exposing platelets with a key role in the coagulation process disconnect from a thrombus by integrin inactivation via an unknown mechanism. Here we show that αIIbβ3 inactivation in procoagulant platelets relies on a sustained high intracellular Ca(2+), stimulating intracellular cleavage of the β3 chain, talin, and Src kinase. Inhibition of calpain activity abolished protein cleavage, but only partly suppressed αIIbβ3 inactivation. Integrin αIIbβ3 inactivation was unchanged in platelets from Capn1(-/-) mice, suggesting a role of the calpain-2 isoform. Scott syndrome platelets, lacking the transmembrane protein TMEM16F and having low phosphatidylserine exposure, displayed reduced αIIbβ3 inactivation with the remaining activity fully dependent on calpain. In platelets from Ppif(-/-) mice, lacking mitochondrial permeability transition pore (mPTP) formation, agonist-induced phosphatidylserine exposure and αIIbβ3 inactivation were reduced. Treatment of human platelets with cyclosporin A gave a similar phenotype. Together, these data point to a dual mechanism of αIIbβ3 inactivation via calpain(-2) cleavage of integrin-associated proteins and via TMEM16F-dependent phospholipid scrambling with an assistant role of mPTP formation.
-
Lee, Jung-Jin; Yang, Hyun; Yoo, Yeong-Min; Hong, Seong Su; Lee, Dongho; Lee, Hyun-Jung; Lee, Hak-Ju; Myung, Chang-Seon; Choi, Kyung-Chul; Jeung, Eui-Bae
2012-01-01
Morus alba (white mulberry) has been used in traditional Chinese medicine as an anti-headache, diuretic, expectorant, and anti-diabetic agent. In previous studies, extracts of Morus alba demonstrated favorable biological properties, such as antioxidant activity, suppression of lipoxygenase (LOX)-1, cytotoxicity against cancer cells, and inhibition of the invasion and migration of cancer cells. This study further evaluated the effects of morusinol, a flavonoid derived from Morus alba root bark, on platelet aggregation and thromboxane B(2) (TXB(2) formation in vitro and thrombus formation in vivo. The antiplatelet potential of morusinol was measured using in vitro rabbit platelet aggregation and TXB(2) formation assays. Arterial thrombus formation was investigated using an in vivo ferric chloride (FeCl(3)-induced thrombosis model. Morusinol significantly inhibited collagen- and arachidonic acid-induced platelet aggregation and TXB(2) formation in cultured platelets in a concentration-dependent manner. Thrombus formation was reduced by 32.1, 42.0, and 99.0% for collagen-induced TXB(2) formation, and 8.0, 24.1, and 29.2% for arachadonic acid-induced TXB(2) formation, with 5, 10, and 30 µg/mL morusinol, respectively. Moreover, oral morusinol (20 mg/kg) or aspirin (20 mg/kg) for three days significantly increased the time to occlusion in vivo by 20.3±5.0 or 6.8±2.9 min, respectively, compared with the control (1% CMC, carboxymethyl cellulose). Taken together, these results indicate that morusinol may significantly inhibit arterial thrombosis in vivo due to antiplatelet activity. Thus, morusinol may exert beneficial effects on transient ischemic attacks or stroke via the modulation of platelet activation.
-
The Role of Platelet and its Interaction with Aspirin
Directory of Open Access Journals (Sweden)
Luisa Fernanda Zúñiga Cerón
2016-04-01
Conclusion. It is recognized the role of platelet in different physiopathological processes and thus its interaction with aspirin, preventing its aggregation and thrombus formation in the spleen and other organs, this way contributing to the prevention of future cardiovascular events.
-
Thomas, Grace M.; Panicot-Dubois, Laurence; Lacroix, Romaric; Dignat-George, Françoise; Lombardo, Dominique
2009-01-01
Recent publications have demonstrated the presence of tissue factor (TF)–bearing microparticles (MPs) in the blood of patients suffering from cancer. However, whether these MPs are involved in thrombosis remains unknown. We show that pancreatic and lung cancer cells produce MPs that express active TF and P-selectin glycoprotein ligand 1 (PSGL-1). Cancer cell–derived MPs aggregate platelets via a TF-dependent pathway. In vivo, cancer cell–derived MPs, but not their parent cells, infused into a living mouse accumulate at the site of injury and reduce tail bleeding time and the time to occlusion of venules and arterioles. This thrombotic state is also observed in mice developing tumors. In such mice, the amount of circulating platelet-, endothelial cell–, and cancer cell–derived MPs is increased. Endogenous cancer cell–derived MPs shed from the growing tumor are able to accumulate at the site of injury. Infusion of a blocking P-selectin antibody abolishes the thrombotic state observed after injection of MPs or in mice developing a tumor. Collectively, our results indicate that cancer cell–derived MPs bearing PSGL-1 and TF play a key role in thrombus formation in vivo. Targeting these MPs could be of clinical interest in the prevention of thrombosis and to limit formation of metastasis in cancer patients. PMID:19667060
-
Sakota, Daisuke; Murashige, Tomotaka; Kosaka, Ryo; Nishida, Masahiro; Maruyama, Osamu
2014-09-01
Blood coagulation is one of the primary concerns when using mechanical circulatory support devices such as blood pumps. Noninvasive detection and imaging of thrombus formation is useful not only for the development of more hemocompatible devices but also for the management of blood coagulation to avoid risk of infarction. The objective of this study is to investigate the use of near-infrared light for imaging of thrombus formation in a rotary blood pump. The optical properties of a thrombus at wavelengths ranging from 600 to 750 nm were analyzed using a hyperspectral imaging (HSI) system. A specially designed hydrodynamically levitated centrifugal blood pump with a visible bottom area was used. In vitro antithrombogenic testing was conducted five times with the pump using bovine whole blood in which the activated blood clotting time was adjusted to 200 s prior to the experiment. Two halogen lights were used for the light sources. The forward scattering through the pump and backward scattering on the pump bottom area were imaged using the HSI system. HSI showed an increase in forward scattering at wavelengths ranging from 670 to 750 nm in the location of thrombus formation. The time at which the thrombus began to form in the impeller rotating at 2780 rpm could be detected. The spectral difference between the whole blood and the thrombus was utilized to image thrombus formation. The results indicate the feasibility of dynamically detecting and imaging thrombus formation in a rotary blood pump. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.
-
Antibody-targeted thrombus imaging and thrombolysis
International Nuclear Information System (INIS)
Wu Guoxin; Ruan Changgeng
1993-05-01
In respect of thrombus imaging, the femoral arterial or venous thrombus model was prepared in dogs and imaged with single photon emission computerized tomography (SPECT). After 4 hours of injection of 131 I-SZ-51 the radioactivity ratio between thrombus and blood (T/B) was 18 : 1 and 8 : 1 for arterial and venous thrombus respectively. The result conformed with the T/B ratio of the removed thrombus and blood after 24 hours of injection of radiotracer. It indicates that the McAb SZ-51 has a great potential to bind with thrombus. In respect of thrombolysis, the Fab(fragment, antigen-binding) fragment of McAb SZ-51 was chemically conjugated of urokinase (UK) by the disulfide-linking reagent SPDP and 2-iminothiolane. The resulting conjugate was 3 to 5 times as potent as UK in vitro in human platelet-rich plasma assay. The increase of fibrinolytic potency was accompanied by a decrease of consumption of plasminogen and fibrinogen. It shows that the increase of potency is the result of selectivity increase
-
Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei
2013-01-01
Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an α(IIb)β₃ antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment.
-
DREAM plays an important role in platelet activation and thrombogenesis
Kim, Kyungho; Tseng, Alan; Barazia, Andrew; Italiano, Joseph E.
2017-01-01
Downstream regulatory element antagonist modulator (DREAM), a transcriptional repressor, is known to modulate pain responses. However, it is unknown whether DREAM is expressed in anucleate platelets and plays a role in thrombogenesis. By using intravital microscopy with DREAM-null mice and their bone marrow chimeras, we demonstrated that both hematopoietic and nonhematopoietic cell DREAMs are required for platelet thrombus formation following laser-induced arteriolar injury. In a FeCl3-induced thrombosis model, we found that compared with wild-type (WT) control and nonhematopoietic DREAM knockout (KO) mice, DREAM KO control and hematopoietic DREAM KO mice showed a significant delay in time to occlusion. Tail bleeding time was prolonged in DREAM KO control mice, but not in WT or DREAM bone marrow chimeric mice. In vivo adoptive transfer experiments further indicated the importance of platelet DREAM in thrombogenesis. We found that DREAM deletion does not alter the ultrastructural features of platelets but significantly impairs platelet aggregation and adenosine triphosphate secretion induced by numerous agonists (collagen-related peptide, adenosine 5′-diphosphate, A23187, thrombin, or U46619). Biochemical studies revealed that platelet DREAM positively regulates phosphoinositide 3-kinase (PI3K) activity during platelet activation. Using DREAM-null platelets and PI3K isoform-specific inhibitors, we observed that platelet DREAM is important for α-granule secretion, Ca2+ mobilization, and aggregation through PI3K class Iβ (PI3K-Iβ). Genetic and pharmacological studies in human megakaryoblastic MEG-01 cells showed that DREAM is important for A23187-induced Ca2+ mobilization and its regulatory function requires Ca2+ binding and PI3K-Iβ activation. These results suggest that platelet DREAM regulates PI3K-Iβ activity and plays an important role during thrombus formation. PMID:27903531
-
International Nuclear Information System (INIS)
Delewi, Ronak; Nijveldt, Robin; Hirsch, Alexander; Marcu, Constantin B.; Robbers, Lourens; Hassell, Marriela E.C.J.; Bruin, Rianne H.A. de; Vleugels, Jim; Laan, Anja M. van der; Bouma, Berto J.; Tio, René A.; Tijssen, Jan G.P.; Rossum, Albert C. van; Zijlstra, Felix; Piek, Jan J.
2012-01-01
Introduction: Left ventricular (LV) thrombus formation is a feared complication of myocardial infarction (MI). We assessed the prevalence of LV thrombus in ST-segment elevated MI patients treated with percutaneous coronary intervention (PCI) and compared the diagnostic accuracy of transthoracic echocardiography (TTE) to cardiovascular magnetic resonance imaging (CMR). Also, we evaluated the course of LV thrombi in the modern era of primary PCI. Methods: 200 patients with primary PCI underwent TTE and CMR, at baseline and at 4 months follow-up. Studies were analyzed by two blinded examiners. Patients were seen at 1, 4, 12, and 24 months for assessment of clinical status and adverse events. Results: On CMR at baseline, a thrombus was found in 17 of 194 (8.8%) patients. LV thrombus resolution occurred in 15 patients. Two patients had persistence of LV thrombus on follow-up CMR. On CMR at four months, a thrombus was found in an additional 12 patients. In multivariate analysis, thrombus formation on baseline CMR was independently associated with, baseline infarct size (g) (B = 0.02, SE = 0.02, p < 0.001). Routine TTE had a sensitivity of 21–24% and a specificity of 95–98% compared to CMR for the detection of LV thrombi. Intra- and interobserver variation for detection of LV thrombus were lower for CMR (κ = 0.91 and κ = 0.96) compared to TTE (κ = 0.74 and κ = 0.53). Conclusion: LV thrombus still occurs in a substantial amount of patients after PCI-treated MI, especially in larger infarct sizes. Routine TTE had a low sensitivity for the detection of LV thrombi and the interobserver variation of TTE was large.
-
Energy Technology Data Exchange (ETDEWEB)
Delewi, Ronak [Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Interuniversity Cardiology Institute of the Netherlands (Netherlands); Nijveldt, Robin [Department of Cardiology, VU University Medical Center, Amsterdam (Netherlands); Hirsch, Alexander [Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Marcu, Constantin B.; Robbers, Lourens [Department of Cardiology, VU University Medical Center, Amsterdam (Netherlands); Hassell, Marriela E.C.J.; Bruin, Rianne H.A. de; Vleugels, Jim; Laan, Anja M. van der; Bouma, Berto J. [Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Tio, René A. [Thorax Center, University Medical Center Groningen, Groningen (Netherlands); Tijssen, Jan G.P. [Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Rossum, Albert C. van [Department of Cardiology, VU University Medical Center, Amsterdam (Netherlands); Zijlstra, Felix [Thorax Center, Department of Cardiology, Erasmus University Medical Center, Rotterdam (Netherlands); Piek, Jan J., E-mail: j.j.piek@amc.uva.nl [Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands)
2012-12-15
Introduction: Left ventricular (LV) thrombus formation is a feared complication of myocardial infarction (MI). We assessed the prevalence of LV thrombus in ST-segment elevated MI patients treated with percutaneous coronary intervention (PCI) and compared the diagnostic accuracy of transthoracic echocardiography (TTE) to cardiovascular magnetic resonance imaging (CMR). Also, we evaluated the course of LV thrombi in the modern era of primary PCI. Methods: 200 patients with primary PCI underwent TTE and CMR, at baseline and at 4 months follow-up. Studies were analyzed by two blinded examiners. Patients were seen at 1, 4, 12, and 24 months for assessment of clinical status and adverse events. Results: On CMR at baseline, a thrombus was found in 17 of 194 (8.8%) patients. LV thrombus resolution occurred in 15 patients. Two patients had persistence of LV thrombus on follow-up CMR. On CMR at four months, a thrombus was found in an additional 12 patients. In multivariate analysis, thrombus formation on baseline CMR was independently associated with, baseline infarct size (g) (B = 0.02, SE = 0.02, p < 0.001). Routine TTE had a sensitivity of 21–24% and a specificity of 95–98% compared to CMR for the detection of LV thrombi. Intra- and interobserver variation for detection of LV thrombus were lower for CMR (κ = 0.91 and κ = 0.96) compared to TTE (κ = 0.74 and κ = 0.53). Conclusion: LV thrombus still occurs in a substantial amount of patients after PCI-treated MI, especially in larger infarct sizes. Routine TTE had a low sensitivity for the detection of LV thrombi and the interobserver variation of TTE was large.
-
Tumor thrombus formation in two dogs with insulinomas.
Hambrook, Lydia E; Kudnig, Simon T
2012-10-15
A 9-year-old sexually intact male Staffordshire Bull Terrier and a 9-year-old neutered male Boxer were evaluated for intermittent neurologic signs including muscle tremors, ataxia, episodic collapse, disorientation, and seizures. Both dogs had low blood glucose and high serum insulin concentrations. Results of abdominal ultrasonography were unremarkable for both dogs. Exploratory laparotomy revealed a mass that extended from the body of the pancreas into the pancreaticoduodenal vein in each dog. Marginal resection of pancreatic masses was performed, and tumor thrombi were removed via venotomy in both dogs. Histologic evaluation indicated the masses were pancreatic islet cell tumors with tumor thrombi. Clinical signs resolved following surgical resection of tumors and tumor thrombi, and the dogs were euglycemic during the follow-up period (17 and 45 months after surgery). Although gross tumor thrombus formation has been identified in humans with insulinomas, tumor thrombi have not been previously reported for dogs with insulinomas. Surgical removal of tumor thrombi via venotomy seemed to be well tolerated by the dogs. Tumor thrombus formation did not seem to adversely affect prognosis for the 2 dogs of this report.
-
Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei
2013-01-01
Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an αIIbβ3 antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment. PMID:23383331
-
Directory of Open Access Journals (Sweden)
Tomasz Brzoska
Full Text Available Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyzed using Confocal Laser Scanning Microscopy. Almost all platelets exposed PS after treatment with tissue factor, thrombin or ionomycin. Argatroban abrogated fibrin network formation in all samples, however, platelet PS exposure was inhibited only in tissue factor- and thrombin-treated samples but not in ionomycin-treated samples. FK633, an α(IIbβ₃ antagonist, and cytochalasin B impaired platelet binding to the fibrin scaffold and significantly reduced PS exposure evoked by thrombin. Gly-Pro-Arg-Pro amide abrogated not only fibrin network formation, but also PS exposure on platelets without suppressing platelet binding to fibrin/fibrinogen. These results suggest that outside-in signals in platelets generated by their binding to the rigid fibrin network are essential for PS exposure after thrombin treatment.
-
Directory of Open Access Journals (Sweden)
H. Z. Batur Caglayan
2013-01-01
Full Text Available Reactive thrombocytosis secondary to iron-deficiency anemia (IDA is a rare but recognized cause of stroke. We report the case of a patient with iron-deficiency anemia presenting with multiple transient ischemic attacks (TIA due to intraluminal thrombus of an internal carotid artery. The putative mechanisms underlying anemia and stroke syndromes are not completely understood, and it is believed that iron deficiency may cause ischemic stroke by several potential mechanisms. Thrombocytosis is often associated with iron deficiency, and microcytosis produces a reduction in the red cell deformability and could produce a hypercoagulable state. The platelet count and function observed in iron-deficiency anemia could act synergistically to promote thrombus formation, especially in the setting of an underlying atherosclerotic disease. The presence of floating thrombus in a patient with clinical and MRI evidence of stroke represents a significant therapeutic dilemma and requires immediate decision about treatment.
-
Detection of intracardiac thrombi by scintiphotography with 111In-labeled autologous platelets
International Nuclear Information System (INIS)
Yui, Tokuo; Uchida, Tatsumi; Matsuda, Shin
1982-01-01
Detection of intracardiac thrombi by scintigraphy with In-111-oxine labeled autologous platelets was studied in 14 patients with various heart diseases. The results of platelet scintigraphy were compared with those of two dimensional echocardiography. In 4 of the 14 patients, the findings on platelet scintigraphy and echocardiography were both positive. Left atrial thrombi were detected in 3 patients with mitral valve disease (MVD), and left ventricular thrombus in a patient with myocardial infarction with left ventricular aneurysm (MI). The scintigraphy after antiplatelet therapy in the patient with MI did not show any radioactivity on the thrombus. In one of the 14 patients with MVD, the finding on platelet scintigraphy was positive, on the other hand echocardiography was negative. In one of the 14 patients with MVD, the finding on platelet scintigraphy was negative, on the other hand that on echocardiography was positive. The thrombus in this case may be hematologically nonactive thrombus. In-111 platelet scintigraphy is considered to be an excellent method for the diagnosis and in vivo assessment of antithrombotic therapy on intracardiac thrombosis. (J.P.N.)
-
The Use of Fluid Mechanics to Predict Regions of Microscopic Thrombus Formation in Pulsatile VADs.
Topper, Stephen R; Navitsky, Michael A; Medvitz, Richard B; Paterson, Eric G; Siedlecki, Christopher A; Slattery, Margaret J; Deutsch, Steven; Rosenberg, Gerson; Manning, Keefe B
2014-03-01
We compare the velocity and shear obtained from particle image velocimetry (PIV) and computational fluid dynamics (CFD) in a pulsatile ventricular assist device (VAD) to further test our thrombus predictive methodology using microscopy data from an explanted VAD. To mimic physiological conditions in vitro , a mock circulatory loop is used with a blood analog that matched blood's viscoelastic behavior at 40% hematocrit. Under normal physiologic pressures and for a heart rate of 75 bpm, PIV data is acquired and wall shear maps are produced. The resolution of the PIV shear rate calculations are tested using the CFD and found to be in the same range. A bovine study, using a model of the 50 cc Penn State V-2 VAD, for 30 days at a constant beat rate of 75 beats per minute (bpm) provides the microscopic data whereby after the 30 days, the device is explanted and the sac surface analyzed using scanning electron microscopy (SEM) and, after immunofluorescent labeling for platelets and fibrin, confocal microscopy. Areas are examined based on PIV measurements and CFD, with special attention to low shear regions where platelet and fibrin deposition are most likely to occur. Data collected within the outlet port in a direction normal to the front wall of the VAD shows that some regions experience wall shear rates less than 500 s -1 , which increases the likelihood of platelet and fibrin deposition. Despite only one animal study, correlations between PIV, CFD, and in vivo data show promise. Deposition probability is quantified by the thrombus susceptibility potential, a calculation to correlate low shear and time of shear with deposition.
-
Sevuk, Utkan; Altindag, Rojhat; Bahadir, Mehmet Veysi; Ay, Nurettin; Demirtas, Ertan; Ayaz, Fırat
2015-03-01
We aimed to evaluate whether mean platelet volume (MPV) and platelet distribution width (PDW) are helpful to identify complete thrombus resolution (CTR) after acute deep venous thrombosis (DVT). Patients who had first-time episode of acute proximal DVT were included in this retrospective study. 100 patients with DVT were divided into two groups according to absence (group 1; n = 68) or presence (group 2; n = 32) of CTR on doppler ultrasonography at month 6. There were no significant difference in admission MPV and PDW levels between group 1 and group 2. MPV (p = 0.03) and PDW (p venous thrombosis in DVT patients. Receiver operating characteristics analysis revealed that a 8.4 % decrease in admission MPV at month 6 provided 62 % sensitivity and 62 % specificity (AUC: 0.64) and a 15.4 % decrease in admission PDW at month 6 provided 87 % sensitivity and 94 % specificity (AUC: 0.89) for prediction of CTR in DVT patients. Percent change in admission MPV and PDW levels at month 6 may be used to identify the patients with CTR after a first episode of acute proximal DVT.
-
Johansson, P I; Svendsen, M S; Salado, J; Bochsen, L; Kristensen, A T
2008-02-01
Transfusion based on the Thrombelastograph (TEG) results reduces transfusion requirements in cardiac surgery and in liver transplantation. Taking the pivotal role of thrombin generation in the coagulation process into consideration, the clinical utility of the TEG may, in part, depend on its reflection of the dynamics of thrombin generation. The kinetics of thrombin generation of platelets stored for 2 and 7 days, respectively, was assessed by calibrated automated thrombogram (CAT) and the lag time (min), time to peak (ttPeak; min), peak (nm thrombin) and endogenous thrombin potential (ETP; nm thrombin*min) were registered. Clot formation was evaluated by TEG and the R time (min), maxial amplitude (MA; mm), time to maximum thrombus generation (TMG; min) and maximum thrombus generation (MTG; dynes cm(-2) s(-1)) and total thrombus generation (TTG; dyne cm(-2)) were registered. Platelets become more procoagulant, evaluated both by TEG and CAT during storage. The reduction in CAT lag time and the ttPeak correlated with a decrease in the TEG R time and TMG (P < 0.0001) as did the CAT peak thrombin generation and the TEG MTG (P = 0.0035). No correlation between ETP and TTG was found (P = 0.65). The kinetics of thrombin generation, as evaluated by CAT, correlates with the thrombus generation, as evaluated by thrombelastography and this may in part explain the clinical utility of the TEG in identifying clinically relevant coagulopathies, secondary to impaired thrombin generation.
-
Musumeci, Lucia; Kuijpers, Marijke J; Gilio, Karen; Hego, Alexandre; Théâtre, Emilie; Maurissen, Lisbeth; Vandereyken, Maud; Diogo, Catia V; Lecut, Christelle; Guilmain, William; Bobkova, Ekaterina V; Eble, Johannes A; Dahl, Russell; Drion, Pierre; Rascon, Justin; Mostofi, Yalda; Yuan, Hongbin; Sergienko, Eduard; Chung, Thomas D Y; Thiry, Marc; Senis, Yotis; Moutschen, Michel; Mustelin, Tomas; Lancellotti, Patrizio; Heemskerk, Johan W M; Tautz, Lutz; Oury, Cécile; Rahmouni, Souad
2015-02-17
A limitation of current antiplatelet therapies is their inability to separate thrombotic events from bleeding occurrences. A better understanding of the molecular mechanisms leading to platelet activation is important for the development of improved therapies. Recently, protein tyrosine phosphatases have emerged as critical regulators of platelet function. This is the first report implicating the dual-specificity phosphatase 3 (DUSP3) in platelet signaling and thrombosis. This phosphatase is highly expressed in human and mouse platelets. Platelets from DUSP3-deficient mice displayed a selective impairment of aggregation and granule secretion mediated by the collagen receptor glycoprotein VI and the C-type lectin-like receptor 2. DUSP3-deficient mice were more resistant to collagen- and epinephrine-induced thromboembolism compared with wild-type mice and showed severely impaired thrombus formation on ferric chloride-induced carotid artery injury. Intriguingly, bleeding times were not altered in DUSP3-deficient mice. At the molecular level, DUSP3 deficiency impaired Syk tyrosine phosphorylation, subsequently reducing phosphorylation of phospholipase Cγ2 and calcium fluxes. To investigate DUSP3 function in human platelets, a novel small-molecule inhibitor of DUSP3 was developed. This compound specifically inhibited collagen- and C-type lectin-like receptor 2-induced human platelet aggregation, thereby phenocopying the effect of DUSP3 deficiency in murine cells. DUSP3 plays a selective and essential role in collagen- and C-type lectin-like receptor 2-mediated platelet activation and thrombus formation in vivo. Inhibition of DUSP3 may prove therapeutic for arterial thrombosis. This is the first time a protein tyrosine phosphatase, implicated in platelet signaling, has been targeted with a small-molecule drug. © 2014 American Heart Association, Inc.
-
Directory of Open Access Journals (Sweden)
Stefan Asbach
2011-01-01
Full Text Available Objective. Despite the use of anticoagulation during left atrial (LA ablation procedures, ischemic cerebrovascular accidents (CVAs are recognized as a serious complication. Heparin is usually given after safe transseptal access has been obtained, resulting in a short unprotected dwell time of catheters within the LA, which may account for CVAs. We investigated the frequency of CVAs and LA thrombus formation as detected by intracardiac ultrasound (ICE depending on the timing of heparin administration. Methods and Results. Sixty LA ablation procedures with the use of ICE were performed in 55 patients. Patients were grouped by heparin administration after (Group I, =13 and before (Group II, =47 transseptal access. Group I patients were younger (56.6±13.7 versus 65.9±9.9 years, =.01; other clinical and echocardiographic characteristics did not differ between groups. Early thrombus formation was observed in 2 (15.4% of group I patients as compared to 0% of group II patients (=.04. One CVA (2.1% occurred in one group II patient without prior thrombus detection, and none occurred in group I patients (=ns. Conclusion. Early administration of heparin reduces the risk of early intracardiac thrombus formation during LA ablation procedures. This did not result in reduced rate of CVAs.
-
Equid herpesvirus type 1 activates platelets.
Directory of Open Access Journals (Sweden)
Tracy Stokol
Full Text Available Equid herpesvirus type 1 (EHV-1 causes outbreaks of abortion and neurological disease in horses. One of the main causes of these clinical syndromes is thrombosis in placental and spinal cord vessels, however the mechanism for thrombus formation is unknown. Platelets form part of the thrombus and amplify and propagate thrombin generation. Here, we tested the hypothesis that EHV-1 activates platelets. We found that two EHV-1 strains, RacL11 and Ab4 at 0.5 or higher plaque forming unit/cell, activate platelets within 10 minutes, causing α-granule secretion (surface P-selectin expression and platelet microvesiculation (increased small events double positive for CD41 and Annexin V. Microvesiculation was more pronounced with the RacL11 strain. Virus-induced P-selectin expression required plasma and 1.0 mM exogenous calcium. P-selectin expression was abolished and microvesiculation was significantly reduced in factor VII- or X-deficient human plasma. Both P-selectin expression and microvesiculation were re-established in factor VII-deficient human plasma with added purified human factor VIIa (1 nM. A glycoprotein C-deficient mutant of the Ab4 strain activated platelets as effectively as non-mutated Ab4. P-selectin expression was abolished and microvesiculation was significantly reduced by preincubation of virus with a goat polyclonal anti-rabbit tissue factor antibody. Infectious virus could be retrieved from washed EHV-1-exposed platelets, suggesting a direct platelet-virus interaction. Our results indicate that EHV-1 activates equine platelets and that α-granule secretion is a consequence of virus-associated tissue factor triggering factor X activation and thrombin generation. Microvesiculation was only partly tissue factor and thrombin-dependent, suggesting the virus causes microvesiculation through other mechanisms, potentially through direct binding. These findings suggest that EHV-1-induced platelet activation could contribute to the thrombosis
-
Potential fluid mechanic pathways of platelet activation.
Shadden, Shawn C; Hendabadi, Sahar
2013-06-01
Platelet activation is a precursor for blood clotting, which plays leading roles in many vascular complications and causes of death. Platelets can be activated by chemical or mechanical stimuli. Mechanically, platelet activation has been shown to be a function of elevated shear stress and exposure time. These contributions can be combined by considering the cumulative stress or strain on a platelet as it is transported. Here, we develop a framework for computing a hemodynamic-based activation potential that is derived from a Lagrangian integral of strain rate magnitude. We demonstrate that such a measure is generally maximized along, and near to, distinguished material surfaces in the flow. The connections between activation potential and these structures are illustrated through stenotic flow computations. We uncover two distinct structures that may explain observed thrombus formation at the apex and downstream of stenoses. More broadly, these findings suggest fundamental relationships may exist between potential fluid mechanic pathways for mechanical platelet activation and the mechanisms governing their transport.
-
Blood platelets in the progression of Alzheimer's disease.
Directory of Open Access Journals (Sweden)
Nina S Gowert
Full Text Available Alzheimer's disease (AD is characterized by neurotoxic amyloid-ß plaque formation in brain parenchyma and cerebral blood vessels known as cerebral amyloid angiopathy (CAA. Besides CAA, AD is strongly related to vascular diseases such as stroke and atherosclerosis. Cerebrovascular dysfunction occurs in AD patients leading to alterations in blood flow that might play an important role in AD pathology with neuronal loss and memory deficits. Platelets are the major players in hemostasis and thrombosis, but are also involved in neuroinflammatory diseases like AD. For many years, platelets were accepted as peripheral model to study the pathophysiology of AD because platelets display the enzymatic activities to generate amyloid-ß (Aß peptides. In addition, platelets are considered to be a biomarker for early diagnosis of AD. Effects of Aß peptides on platelets and the impact of platelets in the progression of AD remained, however, ill-defined. The present study explored the cellular mechanisms triggered by Aß in platelets. Treatment of platelets with Aß led to platelet activation and enhanced generation of reactive oxygen species (ROS and membrane scrambling, suggesting enhanced platelet apoptosis. More important, platelets modulate soluble Aß into fibrillar structures that were absorbed by apoptotic but not vital platelets. This together with enhanced platelet adhesion under flow ex vivo and in vivo and platelet accumulation at amyloid deposits of cerebral vessels of AD transgenic mice suggested that platelets are major contributors of CAA inducing platelet thrombus formation at vascular amyloid plaques leading to vessel occlusion critical for cerebrovascular events like stroke.
-
Proulle, Valerie; Furie, Richard A; Merrill-Skoloff, Glenn; Furie, Barbara C; Furie, Bruce
2014-07-24
Antiphospholipid syndrome (APS) is defined by thrombosis, fetal loss, and the presence of antiphospholipid antibodies, including anti-β2-glycoprotein-1 autoantibodies (anti-β2GP1) that have a direct role in the pathogenesis of thrombosis in vivo. The cellular targets of the anti-β2GP1 autoantibody/β2GP1 complex in vivo were studied using a laser-induced thrombosis model of APS in a live mouse and human anti-β2GP1 autoantibodies affinity-purified from APS patients. Cell binding of fluorescently labeled β2GP1 and anti-β2GP1 autoantibodies revealed their colocalization on the platelet thrombus but not the endothelium. Anti-β2GP1 autoantibodies enhanced platelet activation, monitored by calcium mobilization, and endothelial activation, monitored by intercellular adhesion molecule-1 expression. When eptifibatide was infused to block platelet thrombus formation, enhanced fibrin generation and endothelial cell activation were eliminated. Thus, the anti-β2GP1 autoantibody/β2GP1 complex binds to the thrombus, enhancing platelet activation, and platelet secretion leads to enhanced endothelium activation and fibrin generation. These results lead to a paradigm shift away from the concept that binding of the anti-β2GP1 autoantibody/β2GP1 complex activates both endothelial cells and platelets toward one in which activation of platelets in response to anti-β2GP1 autoantibody/β2GP1 complex binding leads to subsequent enhanced endothelium activation and fibrin generation. © 2014 by The American Society of Hematology.
-
Use of platelets labelled with 111In-Oxine for detection of aortic endocarditis
International Nuclear Information System (INIS)
Rodriguez, V.; Pulpon, L.A.; Rodriguez, E.; Marin, D.; Chamorro, J.L.; Ortiz-Berrocal, J.
1982-01-01
The vegetation is the most characteristic lesion of infective endocarditis. It is constituted mainly of platelets immersed in a fibrin magma, wherein microorganism nest. The damaged vascular endothelium constitutes the first stimulus for the formation of an aseptic platelet thrombus. For this reason, the use of labelled platelets permits first the external detection of formed vegetations and second, by means of serial studies, the study of the evolution of the pathological lesion under treatment with various pharmacological agent. 111 In forms a chelate with the 8-hydroxyquinolein molecule (oxine), and this chelate passes through the platelets membranes and forms a stable bond with cytoplasmic structures. The procedure used in rabbits was useful for the external detection and study of the formation of vegetation induced by infective endocarditis. The technique could be highly useful in the experimental evaluation of antiaggregant agents
-
Rethinking platelet function: thrombocytopenia induced immunodeficiency in critical illness
DEFF Research Database (Denmark)
Ostrowski, Sisse R; Johansson, Per Ingemar
2011-01-01
Thrombocytopenia in critical illness predicts a poor clinical outcome. Apart from its role in microvascular thrombus formation, it is widely anticipated that this association is indirect rather than causal. Emerging evidence however indicates that platelets are also immune competent cells. Like...... per se results in immunodeficiency through loss of platelet-mediated immune functions, and propose that thrombocytopenia induced immunodeficiency in critical illness in part explain the negative predictive value of low or declining platelet count. We propose that rethinking the risks...... of thrombocytopenia to include not only bleeding but also immunodeficiency and immune dysregulation along with the conduct of studies investigating mechanisms contributing to thrombocytopenia induced poor non-hemorrhagic outcome in critical illness, may be means to improve outcome in these patients through...
-
Abnormal megakaryocyte development and platelet function in Nbeal2(-/-) mice.
Kahr, Walter H A; Lo, Richard W; Li, Ling; Pluthero, Fred G; Christensen, Hilary; Ni, Ran; Vaezzadeh, Nima; Hawkins, Cynthia E; Weyrich, Andrew S; Di Paola, Jorge; Landolt-Marticorena, Carolina; Gross, Peter L
2013-11-07
Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and α-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2(-/-) mouse. As in GPS, Nbeal2(-/-) mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet α-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet α-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2(-/-) platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of α-granule biogenesis. Impaired Nbeal2(-/-) platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2(-/-) bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that α-granule secretion plays a significant role in platelet function, and they also indicate that abnormal α-granule formation in Nbeal2(-/-) mice has deleterious effects on megakaryocyte survival, development, and platelet production.
-
Kleinschnitz, Christoph; Braeuninger, Stefan; Pham, Mirko; Austinat, Madeleine; Nölte, Ingo; Renné, Thomas; Nieswandt, Bernhard; Bendszus, Martin; Stoll, Guido
2008-04-01
Models of photochemically-induced thrombosis are widely used in cerebrovascular research. Photothrombotic brain infarctions can be induced by systemic application of photosensitizing dyes followed by focal illumination of the cerebral cortex. Although the ensuing activation of platelets is well established, their contribution for thrombosis and tissue damage has not formally been proved. Infarction to the cerebral cortex was induced in mice by Rose Bengal and a cold light source. To assess the functional role of platelets, animals were platelet-depleted by anti-GPIbalpha antibodies or treated with GPIIb/IIIa-blocking F(ab)(2) fragments. The significance of the plasmatic coagulation cascade was determined by using blood coagulation factor XII (FXII)-deficient mice or heparin. Infarct development and infarct volumes were determined by serial MRI and conventional and electron microscopy. There was no difference in development and final size of photothrombotic infarctions in mice with impaired platelet function. Moreover, deficiency of FXII, which initiates the intrinsic pathway of coagulation and is essential for thrombus formation, or blockade of FXa, the key protease during the waterfall cascade of plasmatic coagulation, by heparin likewise did not affect lesion development. Our data demonstrate that platelet activation, factor XII-driven thrombus formation, and plasmatic coagulation pathways downstream of FX are not a prerequisite for ensuing tissue damage in models of photothrombotic vessel injury indicating that other pathomechanisms are involved. We suggest that this widely used model does not depend on platelet- or plasmatic coagulation-derived thrombosis.
-
Noninvasive detection of coronary thrombi with 111In platelets: concise communication
International Nuclear Information System (INIS)
Bergmann, S.R.; Lerch, R.A.; Mathias, C.J.; Sobel, B.E.; Welch, M.J.
1983-01-01
The need for rapid, definitive identification of coronary thrombosis has been intensified by the advent of thrombolytic therapy and by interest in the role of thrombosis in the etiology of coronary artery disease. To determine whether platelet thrombi can be detected noninvasively with 111 In platelets, a method was developed in which /sup 99m/Tc-tagged red blood cells were used to correct for activity within the blood attributable to platelets circulating but not associated with thrombus. In 18 dogs coronary thrombi were induced closed-chest with a copper coil introduced into the coronary artery. 111 In platelets and /sup 99m/Tc RBCs were administered either before or 1 hr after induction of thrombus, and serial scintigrams obtained. Coronary thrombus was identified readily in the processed scintigrams. In six dogs, thrombolysis was achieved with intracoronary streptokinase. In each case serial scintigraphy demonstrated resolution of the clot. The dual radiotracer technique should permit serial noninvasive delineation of the temporal relationship between platelet deposition and coronary heart disease in patients, and should facilitate the evaluation of interventions designed to prevent platelet aggregation or to lyse existing thrombi
-
Quantitation of thrombogenicity of hemodialyzer with technetium-99m and indium-111 labeled platelets
Energy Technology Data Exchange (ETDEWEB)
Dewanjee, M.K.; Kapadvanjwala, Mansoor; Ruzius, Kees; Serafini, A.N.; Zilleruelo, G.E.; Sfakianakis, G.N. (Miami Univ., FL (United States). School of Medicine Althin CD-Medical Inc., Miami Lakes, FL (United States))
1993-07-01
The platelet thromobogenicity of a hemodialyzer was quantified with [sup 99m]Tc- and [sup 111]In-labeled platelets. The platelets collected from blood of Beagle dogs, Yorkshire pigs and human volunteers were labeled with [sup 111]in-tropolone (detergent-free) and [sup 99m]Tc-HMPAO. Hemodialysis was performed with a hollow-fiber dialyzer (HFD) in a flow-loop, the temperature of which was maintained at 37[sup o]C, with flow-rates of 7, 150 and 270 mL/min; after dialysis, the HFD radioactivity was measured with an ionization chamber and imaged with a [gamma]-camera. The radioactivity of samples of hollow-fibers taken from the top, middle and bottom of the dialyzer was determined with a [gamma]-counter. The mean values of hemodialyzer-adherent platelet radioactivity were calculated for both radionuclides. The canine platelets were found to be more thrombogenic than porcine and human platelets. The adhesivity of porcine platelets to the biomaterial (cellulose-acetate) of the dialyzer approximated that of human platelets. The [sup 99m]Tc label underestimated the thrombus formation (P < 0.01 ). The dynamic processes of thrombosis and embolization from the hemodialyzer resulted in the large standard deviations around the mean values of the adherent thrombus. In spite of this limitation of the dynamic pathology, the quantitation of comparative throbogenicity with [sup 111]In- and [sup 99m]Tc-labeled platelets suggests that both radionuclides could be used for measurement of device-induced thrombogenicity and may provide an estimation of prosthesis-induced thrombogenicity of human platelets from animal studies. (Author).
-
Hurwitz, Seth Eric; Waxman, Daniel; Hecht, Susan
2009-09-01
Pannus formation and valve thrombus can cause prosthetic valve failure. The authors report the case of a 50-year-old woman who presented to the emergency room with decompensated heart failure secondary to mechanical valve dysfunction. On two-dimensional and transesophageal echocardiography, the patient had severe aortic stenosis and regurgitation. A thrombus seen on the valve was felt to be the etiology of her prosthetic valve failure. She underwent emergent cardiac surgery for aortic valve replacement. Pathology revealed that although a small thrombus was present, extensive pannus was the underlying mechanism of valve dysfunction. Differentiation between pannus and thrombus may have important clinical implications, but this case illustrates that distinguishing between these entities by echocardiographic and clinical criteria may not be possible.
-
In vitro model of platelet aggregation in stenotic arteries
International Nuclear Information System (INIS)
Morley, D.; Santamore, W.P.
1988-01-01
Clinical and experimental evidence suggest a strong relationship between arterial stenosis, platelet aggregation, and subsequent thrombus formation. To facilitate the study of platelet accumulation in stenotic arteries, we developed an in vitro preparation. Arterial segments were perfused with whole citrated blood. A stenosis was created by applying an external plastic constrictor to the artery. Platelet accumulation within the stenosis was assessed by scanning electron microscopy and by radioactive counts from Indium-111 labeled platelets. Utilizing this preparation, 30 carotid arterial segments from 10 mongrel dogs were perfused at 100 mmHg for 15 min. In 10 arteries without a stenosis, scanning electron microscopy and radioactive counts demonstrated little platelet accumulation. In contrast, extensive platelet aggregation was observed in 10 arteries with stenoses. Moreover, in 10 stenotic arteries exposed to the thromboxane mimetic, U46619 (Upjohn Diagnostic Group), scanning electron microscopy and radioactive counts demonstrated a significant increase in platelet deposition. Conversely, we demonstrated a dimunition of platelet accumulation in stenosed arterial segments exposed to the prostacyclin analogue platelet inhibitor, Iloprost. The in vitro preparation allows precise control of hemodynamic variables and makes it possible to perform multiple tests on segments of the same vessel from the same animal
-
The role of platelets in hemostasis and the effects of snake venom toxins on platelet function.
de Queiroz, Mayara Ribeiro; de Sousa, Bruna Barbosa; da Cunha Pereira, Déborah Fernanda; Mamede, Carla Cristine Neves; Matias, Mariana Santos; de Morais, Nadia Cristina Gomes; de Oliveira Costa, Júnia; de Oliveira, Fábio
2017-07-01
The human body has a set of physiological processes, known as hemostasis, which keeps the blood fluid and free of clots in normal vessels; in the case of vascular injury, this process induces the local formation of a hemostatic plug, preventing hemorrhage. The hemostatic system in humans presents complex physiological interactions that involve platelets, plasma proteins, endothelial and subendothelial structures. Disequilibrium in the regulatory mechanisms that control the growth and the size of the thrombus is one of the factors that favors the development of diseases related to vascular disorders such as myocardial infarction and stroke, which are among the leading causes of death in the western world. Interfering with platelet function is a strategy for the treatment of thrombotic diseases. Antiplatelet drugs are used mainly in cases related to arterial thrombosis and interfere in the formation of the platelet plug by different mechanisms. Aspirin (acetylsalicylic acid) is the oldest and most widely used antithrombotic drug. Although highly effective in most cases, aspirin has limitations compared to other drugs used in the treatment of homeostatic disorders. For this reason, research related to molecules that interfere with platelet aggregation are of great relevance. In this regard, snake venoms are known to contain a number of molecules that interfere with hemostasis, including platelet function. The mechanisms by which snake venom components inhibit or activate platelet aggregation are varied and can be used as tools for the diagnosis and the treatment of several hemostatic disorders. The aim of this review is to present the role of platelets in hemostasis and the mechanisms by which snake venom toxins interfere with platelet function. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
Rocha, Gladys; Sierralta, Walter; Valladares, Luis
2016-11-01
The decline of estrogen levels increases cardiovascular risk in women. Platelets express estrogen receptors and 17β-estradiol- (E2) can produce a protective effect on thrombus formation. The hydroxylation of cholesterol generates several sterols and 27-hydroxycholesterol (27HC) predominates in circulation. To evaluate the effect of 27HC as an endogenous antagonist of the anti-aggregating properties of E2 in platelets of postmenopausal women. Platelet function of postmenopausal women was evaluated ex-vivo. Platelets pre-incubated with 27HC in the presence or absence of E2, were stimulated with collagen. Aggregation was evaluated using turbidimetry using a Chrono-log aggregometer. Collagen-stimulated platelet aggregation was significantly inhibited by E2. The inhibitory effect of E2 on collagen-stimulated platelet aggregation was significantly reversed in the presence of 27HC. The suppressive effect of E2 on platelet aggregation is inhibited by 27HC, which could contribute to increase cardiovascular risk in postmenopausal women.
-
Brzoska, Tomasz; Suzuki, Yuko; Mogami, Hideo; Sano, Hideto; Urano, Tetsumei
2013-01-01
Recently, by employing intra-vital confocal microscopy, we demonstrated that platelets expose phosphatidylserine (PS) and fibrin accumulate only in the center of the thrombus but not in its periphery. To address the question how exposure of platelet anionic phospholipids is regulated within the thrombus, an in-vitro experiment using diluted platelet-rich plasma was employed, in which the fibrin network was formed in the presence of platelets, and PS exposure on the platelet surface was analyz...
-
Anti-Platelet Treatment of Middle-Sized Abdominal Aortic Aneurysms
DEFF Research Database (Denmark)
Lindholt, Jen S; Björck, Martin; Michel, Jean B
2012-01-01
between the luminal side of the thrombus and flowing blood is a site of constant thrombus renewal, which is linked to platelet aggregation-induced fibrin generation and accumulation. In addition, red blood cells are entrapped causing an oxidative response. Through centrifugal convection are factors...
-
Yamashita, Atsushi; Sumi, Takahiro; Goto, Shinya; Hoshiba, Yasunari; Nishihira, Kensaku; Kawamoto, Riichirou; Hatakeyama, Kinta; Date, Haruhiko; Imamura, Takuroh; Ogawa, Hisao; Asada, Yujiro
2006-01-01
The rapid closure of coronary arteries due to occlusive thrombi is the major cause of acute myocardial infarction. However, the mechanisms of coronary thrombus formation have not been elucidated. We immunohistochemically assessed the localizations and their changes over time of glycoprotein IIb/IIIa, fibrin, von Willebrand factor (vWF), and tissue factor (TF), after the onset of chest pain (platelets, fibrin, vWF, and TF from the early phase of onset, and glycoprotein IIb/IIIa and fibrin were closely associated with vWF and TF, respectively. vWF and/or TF may contribute to occlusive thrombus formation and be novel therapeutic candidates for treating patients with coronary thrombosis.
-
Rac1 is essential for phospholipase C-gamma2 activation in platelets
DEFF Research Database (Denmark)
Pleines, Irina; Elvers, Margitta; Strehl, Amrei
2008-01-01
isoenzymes are activated downstream of G protein-coupled receptors (GPCRs), whereas PLCgamma2 is activated downstream of immunoreceptor tyrosine-based activation motif (ITAM)-coupled receptors, such as the major platelet collagen receptor glycoprotein (GP) VI or CLEC-2. The mechanisms underlying PLC......Platelet activation at sites of vascular injury is triggered through different signaling pathways leading to activation of phospholipase (PL) Cbeta or PLCgamma2. Active PLCs trigger Ca(2+) mobilization and entry, which is a prerequisite for adhesion, secretion, and thrombus formation. PLCbeta...... regulation are not fully understood. An involvement of small GTPases of the Rho family (Rho, Rac, Cdc42) in PLC activation has been proposed but this has not been investigated in platelets. We here show that murine platelets lacking Rac1 display severely impaired GPVI- or CLEC-2-dependent activation...
-
Sakota, Daisuke; Fujiwara, Tatsuki; Ohuchi, Katsuhiro; Kuwana, Katsuyuki; Yamazaki, Hiroyuki; Kosaka, Ryo; Maruyama, Osamu
2018-02-01
We developed an optical detector of thrombus formed on the pivot bearing of an extracorporeal centrifugal blood pump (MERA HCF-MP23; Senko Medical Instrument Mfg. Co., Ltd., Tokyo, Japan) which is frequently used for long-term extracorporeal circulation support to bridge to an implantable artificial heart, which in turn is used for bridge to heart transplantation in Japan. In this study, we investigated the quantitative performance of the thrombus formation in acute animal experiments. A total of three experiments of extracorporeal left ventricular assist using Japanese specific pathogen-free pigs were conducted. The optical fibers were set in the pump driver unit. The incident light at nearinfrared wavelength aiming at the pivot bearing and the resulting scattered light were guided to respective fibers. The detected signal was analyzed to obtain thrombus formation level (TFL) calculated by a specially developed software. When the increase in TFL was confirmed, the pump was exchanged and the extracorporeal circulation was restarted. The number of pump exchanges were four times at each experiment so a total of twelve pumps were evaluated. 3-dimentional data surrounding the pivot bearing and the adhered thrombus was captured by a 3-dimantional surface measurement system to calculate the thrombus surface area (TSA) formed on the pivot bearing. As a result, the correlation coefficient between TFL and TSA was 0.878. The accuracy of TSA estimated by the optical detector was 3.6+/-2.3 mm2. This was small enough to not have the pump exchanged in clinical judgement. The developed detector would be useful for optimal anti-coagulation management.
-
Directory of Open Access Journals (Sweden)
Ken Aizawa
2015-03-01
Full Text Available Sirolimus (SRL is widely used to prevent restenosis after percutaneous coronary intervention. However, its beneficial effect is hampered by complications of thrombosis. Several studies imply that reactive oxygen species (ROS play a critical role in endothelial dysfunction and thrombus formation. The present study investigated the protective effect of nicorandil (NIC, an anti-angina agent, on SRL-associated thrombosis. In human coronary artery endothelial cells (HCAECs, SRL stimulated ROS production, which was prevented by co-treatment with NIC. The preventive effect of NIC on ROS was abolished by 5-hydroxydecanoate but not by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one. NIC also inhibited SRL-induced up-regulation of NADPH oxidase subunit p22phox mRNA. Co-treatment with NIC and SRL significantly up-regulated superoxide dismutase 2. NIC treatment significantly improved SRL-induced decrease in viability of HCAECs. The functional relevance of the preventive effects of NIC on SRL-induced ROS production and impairment of endothelial viability was investigated in a mouse model of thrombosis. Pretreatment with NIC inhibited the SRL-induced acceleration of FeCl3-initiated thrombus formation and ROS production in the testicular arteries of mice. In conclusion, NIC prevented SRL-induced thrombus formation, presumably due to the reduction of ROS and to endothelial protection. The therapeutic efficacy of NIC could represent an additional option in the prevention of SRL-related thrombosis.
-
Directory of Open Access Journals (Sweden)
Daniella M Mizurini
Full Text Available The saliva of blood-feeding arthropods contains a notable diversity of molecules that target the hemostatic and immune systems of the host. Dipetalodipin and triplatin are triatomine salivary proteins that exhibit high affinity binding to prostanoids, such as TXA2, thus resulting in potent inhibitory effect on platelet aggregation in vitro. It was recently demonstrated that platelet-derived TXA2 mediates the formation of neutrophil extracellular traps (NETs, a newly recognized link between inflammation and thrombosis that promote thrombus growth and stability.This study evaluated the ability of dipetalodipin and triplatin to block NETs formation in vitro. We also investigated the in vivo antithrombotic activity of TXA2 binding proteins by employing two murine models of experimental thrombosis. Remarkably, we observed that both inhibitors abolished the platelet-mediated formation of NETs in vitro. Dipetalodipin and triplatin significantly increased carotid artery occlusion time in a FeCl3-induced injury model. Treatment with TXA2-binding proteins also protected mice from lethal pulmonary thromboembolism evoked by the intravenous injection of collagen and epinephrine. Effective antithrombotic doses of dipetalodipin and triplatin did not increase blood loss, which was estimated using the tail transection method.Salivary TXA2-binding proteins, dipetalodipin and triplatin, are capable to prevent platelet-mediated NETs formation in vitro. This ability may contribute to the antithrombotic effects in vivo. Notably, both molecules inhibit arterial thrombosis without promoting excessive bleeding. Our results provide new insight into the antihemostatic effects of TXA2-binding proteins and may have important significance in elucidating the mechanisms of saliva to avoid host's hemostatic responses and innate immune system.
-
Multi-Constituent Simulation of Thrombus Deposition.
Wu, Wei-Tao; Jamiolkowski, Megan A; Wagner, William R; Aubry, Nadine; Massoudi, Mehrdad; Antaki, James F
2017-02-20
In this paper, we present a spatio-temporal mathematical model for simulating the formation and growth of a thrombus. Blood is treated as a multi-constituent mixture comprised of a linear fluid phase and a thrombus (solid) phase. The transport and reactions of 10 chemical and biological species are incorporated using a system of coupled convection-reaction-diffusion (CRD) equations to represent three processes in thrombus formation: initiation, propagation and stabilization. Computational fluid dynamic (CFD) simulations using the libraries of OpenFOAM were performed for two illustrative benchmark problems: in vivo thrombus growth in an injured blood vessel and in vitro thrombus deposition in micro-channels (1.5 mm × 1.6 mm × 0.1 mm) with small crevices (125 μm × 75 μm and 125 μm × 137 μm). For both problems, the simulated thrombus deposition agreed very well with experimental observations, both spatially and temporally. Based on the success with these two benchmark problems, which have very different flow conditions and biological environments, we believe that the current model will provide useful insight into the genesis of thrombosis in blood-wetted devices, and provide a tool for the design of less thrombogenic devices.
-
Multi-Constituent Simulation of Thrombus Deposition
Wu, Wei-Tao; Jamiolkowski, Megan A.; Wagner, William R.; Aubry, Nadine; Massoudi, Mehrdad; Antaki, James F.
2017-02-01
In this paper, we present a spatio-temporal mathematical model for simulating the formation and growth of a thrombus. Blood is treated as a multi-constituent mixture comprised of a linear fluid phase and a thrombus (solid) phase. The transport and reactions of 10 chemical and biological species are incorporated using a system of coupled convection-reaction-diffusion (CRD) equations to represent three processes in thrombus formation: initiation, propagation and stabilization. Computational fluid dynamic (CFD) simulations using the libraries of OpenFOAM were performed for two illustrative benchmark problems: in vivo thrombus growth in an injured blood vessel and in vitro thrombus deposition in micro-channels (1.5 mm × 1.6 mm × 0.1 mm) with small crevices (125 μm × 75 μm and 125 μm × 137 μm). For both problems, the simulated thrombus deposition agreed very well with experimental observations, both spatially and temporally. Based on the success with these two benchmark problems, which have very different flow conditions and biological environments, we believe that the current model will provide useful insight into the genesis of thrombosis in blood-wetted devices, and provide a tool for the design of less thrombogenic devices.
-
Deposition of fibrinogen on the surface of in vitro thrombi prevents platelet adhesion.
Owaynat, Hadil; Yermolenko, Ivan S; Turaga, Ramya; Lishko, Valeryi K; Sheller, Michael R; Ugarova, Tatiana P
2015-12-01
The initial accumulation of platelets after vessel injury is followed by thrombin-mediated generation of fibrin which is deposited around the plug. While numerous in vitro studies have shown that fibrin is highly adhesive for platelets, the surface of experimental thrombi in vivo contains very few platelets suggesting the existence of natural anti-adhesive mechanisms protecting stabilized thrombi from platelet accumulation and continuous thrombus propagation. We previously showed that adsorption of fibrinogen on pure fibrin clots results in the formation of a nonadhesive matrix, highlighting a possible role of this process in surface-mediated control of thrombus growth. However, the deposition of fibrinogen on the surface of blood clots has not been examined. In this study, we investigated the presence of intact fibrinogen on the surface of fibrin-rich thrombi generated from flowing blood and determined whether deposited fibrinogen is nonadhesive for platelets. Stabilized fibrin-rich thrombi were generated using a flow chamber and the time that platelets spend on the surface of thrombi was determined by video recording. The presence of fibrinogen and fibrin on the surface of thrombi was analyzed by confocal microscopy using specific antibodies. Examination of the spatial distribution of two proteins revealed the presence of intact fibrinogen on the surface of stabilized thrombi. By manipulating the surface of thrombi to display either fibrin or intact fibrinogen, we found that platelets adhere to fibrin- but not to fibrinogen-coated thrombi. These results indicate that the fibrinogen matrix assembled on the outer layer of stabilized in vitro thrombi protects them from platelet adhesion. Copyright © 2015 Elsevier Ltd. All rights reserved.
-
MEAN PLATELET VOLUME AND RISK OF THROMBOTIC STROKE
Directory of Open Access Journals (Sweden)
Prasantha Kumar Thankappan
2017-07-01
Full Text Available BACKGROUND Stroke is a major cause of long term morbidity and mortality. Several factors are known to increase the liability to stroke. Platelets play a crucial role in the pathogenesis of atherosclerotic complications, contributing to thrombus formation. Platelet size (mean platelet volume, MPV is a marker and possible determinant of platelet function, large platelets being potentially more reactive. Hence an attempt has-been made to study the association if any between mean platelet volume and thrombotic stroke. The aim of this study was to determine whether an association exists between Mean Platelet Volume (MPV and thrombotic stroke. MATERIALS AND METHODS The study is a case control study and data was collected at Government Medical College Hospital, Kottayam, Kerala a tertiary care referral centre. The study was carried out among fifty patients diagnosed with thrombotic stroke and presenting to the hospital within forty eight hours of onset of symptoms. Fifty age group and sex matched controls were also recruited. Mean platelet volume was obtained using a SYSMEX automated analyser. RESULTS This study has shown a statistically significant relation between mean platelet volume and risk of thrombotic stroke but no statistically significant correlation between clinical severity of stroke and mean platelet volume. CONCLUSION This study has shown an elevation of MPV in acute phase of thrombotic stroke. Platelet mass was found to be more or less a constant. This study did not find a statistically significant correlation between clinical severity of stroke and mean platelet volume.
-
Abnormal megakaryocyte development and platelet function in Nbeal2−/− mice
Lo, Richard W.; Li, Ling; Pluthero, Fred G.; Christensen, Hilary; Ni, Ran; Vaezzadeh, Nima; Hawkins, Cynthia E.; Weyrich, Andrew S.; Di Paola, Jorge; Landolt-Marticorena, Carolina; Gross, Peter L.
2013-01-01
Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and α-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2−/− mouse. As in GPS, Nbeal2−/− mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet α-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet α-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2−/− platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of α-granule biogenesis. Impaired Nbeal2−/− platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2−/− bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that α-granule secretion plays a significant role in platelet function, and they also indicate that abnormal α-granule formation in Nbeal2−/− mice has deleterious effects on megakaryocyte survival, development, and platelet production. PMID:23861251
-
Caiazzo, Elisabetta; Tedesco, Idolo; Spagnuolo, Carmela; Russo, Gian Luigi; Ialenti, Armando; Cicala, Carla
2016-06-01
Moderate consumption of red wine has been shown to exert a peculiar cardioprotective effect compared with other alcoholic beverages; inhibition of platelet aggregation seems to be one of the mechanisms underlying this beneficial effect. CD39/ATP-diphosphohydrolase is an integral membrane glycoprotein metabolizing ATP and ADP to AMP; in concert with CD73/ecto-5'-nucleotidase, it contributes to extracellular adenosine accumulation. CD39 is considered a key modulator of thrombus formation; it inhibits platelet aggregation by promoting ADP hydrolysis. There is evidence that red wine consumption increases CD39 activity in platelets from streptozotocin-induced diabetic rats. Here we show that two kinds of Aglianico red wines inhibit aggregation and increase ATP--and ADPase activity in rat platelets.
-
White Thrombus Formation in Blood Tubing Lines in a Chronic Hemodialysis Unit
Watnick, Suzanne; Stooksbury, Michael; Winter, Rolf; Riscoe, Michael; Cohen, David M.
2008-01-01
Background and objectives: Previous reports have described white particulate matter in banked blood components, but no prior public reports describe such matter in blood tubing during the course of routine in-center hemodialysis. This report describes the events, investigations, and preliminary conclusions associated with the spontaneous formation of adherent white thrombus in the venous and arterial blood lines during routine in-center hemodialysis treatments.
-
Platelet RNA as a circulating biomarker trove for cancer diagnostics.
Best, M G; Vancura, A; Wurdinger, T
2017-07-01
Platelets are multifunctional cell fragments, circulating in blood in high abundance. Platelets assist in thrombus formation, sensing of pathogens entering the blood stream, signaling to immune cells, releasing vascular remodeling factors, and, negatively, enhancing cancer metastasis. Platelets are 'educated' by their environment, including in patients with cancer. Cancer cells appear to initiate intraplatelet signaling, resulting in splicing of platelet pre-mRNAs, and enhance secretion of cytokines. Platelets can induce leukocyte and endothelial cell modeling factors, for example, through adenine nucleotides (ATP), thereby facilitating extravasation of cancer cells. Besides releasing factors, platelets can also sequester RNAs and proteins released by cancer cells. Thus, platelets actively respond to queues from local and systemic conditions, thereby altering their transcriptome and molecular content. Platelets contain a rich repertoire of RNA species, including mRNAs, small non-coding RNAs and circular RNAs; although studies regarding the functionality of the various platelet RNA species require more attention. Recent advances in high-throughput characterization of platelet mRNAs revealed 10 to > 1000 altered mRNAs in platelets in the presence of disease. Hence, platelet RNA appears to be dynamically affected by pathological conditions, thus possibly providing opportunities to use platelet RNA as diagnostic, prognostic, predictive, or monitoring biomarkers. In this review, we cover the literature regarding the platelet RNA families, processing of platelet RNAs, and the potential application of platelet RNA as disease biomarkers. © 2017 International Society on Thrombosis and Haemostasis.
-
International Nuclear Information System (INIS)
Ercius, M.S.; Chandler, W.F.; Ford, J.W.; Swanson, D.P.; Burke, J.C.
1984-01-01
Although it is widely accepted that aspirin inhibits platelet aggregation in arterial thrombosis, the appropriate dosage of aspirin remains quite controversial. The purpose of this study was to determine the effect of different doses of aspirin (0.5 mg/kg vs. 10 mg/kg) on mural thrombus formation after carotid endarterectomy. Eighteen hours after oral aspirin administration, 20 endarterectomies were performed on mongrel dogs with the use of the operating microscope. Blood flow was then restored for 3 hours and the vessels were prepared for investigation with the scanning electron microscope. Ten endarterectomies were also performed on unmedicated dogs as controls. Five minutes before vessel unclamping, autologous indium-111-labeled platelets were administered intravenously, and the endarterectomized portions of the vessels were studied with a gamma counter system after harvesting. Group 1, the control group, revealed extensive mural thrombus consisting of platelet aggregates, fibrin, red blood cells, and white blood cells. Six of the 10 vessels in Group 2, premedicated with 0.5 mg of aspirin per kg, demonstrated varying amounts of mural thrombus. Group 3 (10 vessels), premedicated with 10 mg of aspirin per kg, revealed a platelet monolayer completely covering the exposed vessel wall media, with scattered white blood cells and infrequent fine fibrin strands overlying the platelet surface. The mean (+/- SD) radioactivity per group expressed as counts/minute/mm2 was: Group 1--2055.3 +/- 1905.5, log . 7.253 +/- 0.926; Group 2--1235.6 +/- 1234.3, log . 6.785 +/- 0.817; Group 3--526 +/- 433.06, log . 5.989 +/- 0.774
-
Directory of Open Access Journals (Sweden)
V. D. Syvolap
2014-02-01
Full Text Available Introduction. Worldwide myocardial infarction (MI is one of the main causes of morbidity and mortality. Thanks to advances in modern cardiology we achieved a significant reduction in mortality and the incidence of fatal complications of acute Q-wave MI. However, keeping in mind the pathogenetic features of myocardial defeat of the left ventricle (LV cavity dilation and thinning at the focus of myocardial infarction, which increase the risk of left ventricular aneurysm development and parietal thrombus formation, it is impossible to reduce significantly the risk of these serious complications development. Post-infarction left ventricular aneurysm, extremely unfavorable prognostic factor complicates the course of Q-wave myocardial infarction in 30% of cases. The likelihood of parietal clot development in the anterior apical localization of aneurysms is 32%. The reasons of parietal clot formation are varied and are not fully disclosed, that is responsible for the relevance of this study. Aim: to investigate the serum level of protein C, von Willebrand factor, the expression of vascular adhesion molecules sVCAM-1, platelet aggregation properties and to evaluate their relationship with the structural and functional performance of the heart in patients with acute Q-wave myocardial infarction with aneurysm and parietal thrombus of LV. Methods. 110 patients (67 men and 43 women, mean age - 63,2 ± 5,7 years, with a diagnosis of acute Q-wave myocardial infarction were involved into the study. The first group included 72 patients with postinfarction left ventricular aneurysm, the second - 38 patients with postinfarction aneurysm and parietal thrombus of LV. Serum levels of protein C, von Willebrand factor, the expression of vascular adhesion molecules sVCAM-1, platelet aggregation properties were studied and their relationship with the structural and functional performance of the heart were evaluated. Results. There were revealed high activity of the key
-
Directory of Open Access Journals (Sweden)
Ting-Lin Yen
2014-01-01
Full Text Available Amarogentin, an active principle of Gentiana lutea, possess antitumorigenic, antidiabetic, and antioxidative properties. Activation of platelets is associated with intravascular thrombosis and cardiovascular diseases. The present study examined the effects of amarogentin on platelet activation. Amarogentin treatment (15~60 μM inhibited platelet aggregation induced by collagen, but not thrombin, arachidonic acid, and U46619. Amarogentin inhibited collagen-induced phosphorylation of phospholipase C (PLCγ2, protein kinase C (PKC, and mitogen-activated protein kinases (MAPKs. It also inhibits in vivo thrombus formation in mice. In addition, neither the guanylate cyclase inhibitor ODQ nor the adenylate cyclase inhibitor SQ22536 affected the amarogentin-mediated inhibition of platelet aggregation, which suggests that amarogentin does not regulate the levels of cyclic AMP and cyclic GMP. In conclusion, amarogentin prevents platelet activation through the inhibition of PLCγ2-PKC cascade and MAPK pathway. Our findings suggest that amarogentin may offer therapeutic potential for preventing or treating thromboembolic disorders.
-
Biasetti, Jacopo; Hussain, Fazle; Gasser, T Christian
2011-10-07
Abdominal aortic aneurysms (AAAs) are frequently characterized by the development of an intra-luminal thrombus (ILT), which is known to have multiple biochemical and biomechanical implications. Development of the ILT is not well understood, and shear-stress-triggered activation of platelets could be the first step in its evolution. Vortical structures (VSs) in the flow affect platelet dynamics, which motivated the present study of a possible correlation between VS and ILT formation in AAAs. VSs educed by the λ(2)-method using computational fluid dynamics simulations of the backward-facing step problem, normal aorta, fusiform AAA and saccular AAA were investigated. Patient-specific luminal geometries were reconstructed from computed tomography scans, and Newtonian and Carreau-Yasuda models were used to capture salient rheological features of blood flow. Particularly in complex flow domains, results depended on the constitutive model. VSs developed all along the normal aorta, showing that a clear correlation between VSs and high wall shear stress (WSS) existed, and that VSs started to break up during late systole. In contrast, in the fusiform AAA, large VSs developed at sites of tortuous geometry and high WSS, occupying the entire lumen, and lasting over the entire cardiac cycle. Downward motion of VSs in the AAA was in the range of a few centimetres per cardiac cycle, and with a VS burst at that location, the release (from VSs) of shear-stress-activated platelets and their deposition to the wall was within the lower part of the diseased artery, i.e. where the thickest ILT layer is typically observed. In the saccular AAA, only one VS was found near the healthy portion of the aorta, while in the aneurysmatic bulge, no VSs occurred. We present a fluid-dynamics-motivated mechanism for platelet activation, convection and deposition in AAAs that has the potential of improving our current understanding of the pathophysiology of fluid-driven ILT growth.
-
Kaempferol inhibits thrombosis and platelet activation.
Choi, Jun-Hui; Park, Se-Eun; Kim, Sung-Jun; Kim, Seung
2015-08-01
The objectives of the present study were to investigate whether kaempferol affects pro-coagulant proteinase activity, fibrin clot formation, blood clot and thrombin (or collagen/epinephrine)-stimulated platelet activation, thrombosis, and coagulation in ICR (Imprinting Control Region) mice and SD (Sprague-Dawley) rats. Kaempferol significantly inhibited the enzymatic activities of thrombin and FXa by 68 ± 1.6% and 52 ± 2.4%, respectively. Kaempferol also inhibited fibrin polymer formation in turbidity. Microscopic analysis was performed using a fluorescent conjugate. Kaempferol completely attenuated phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38, c-Jun N-terminal kinase (JNK) 1/2, and phosphoinositide 3-kinase (PI3K)/PKB (AKT) in thrombin-stimulated platelets and delayed aggregation time (clotting) by 34.6% in an assay of collagen/epinephrine-stimulated platelet activation. Moreover, kaempferol protected against thrombosis development in 3 animal models, including collagen/epinephrine- and thrombin-induced acute thromboembolism models and an FeCl3-induced carotid arterial thrombus model. The ex vivo anticoagulant effect of kaempferol was further confirmed in ICR mice. This study demonstrated that kaempferol may be clinically useful due to its ability to reduce or prevent thrombotic challenge. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.
-
International Nuclear Information System (INIS)
Stratton, J.R.; Ritchie, J.L.
1984-01-01
Patients with left ventricular thrombi not caused by recent myocardial infarction were prospectively studied by indium-111 platelet imaging and two-dimensional echocardiography to determine the reproducibility of these techniques and the short-term effects of sulfinpyrazone (200 mg four times daily), aspirin (325 mg three times daily) plus dipyridamole (75 mg three times daily), and full-dose warfarin. At baseline, all patients underwent indium-111 platelet imaging and echocardiography, and the results were positive for thrombus. In six patients on no antithrombotic drug therapy, repeat platelet scans and echocardiographic studies at 6.0 +/- 3.3 weeks remained positive and were unchanged. In seven patients studied on sulfinpyrazone, three platelet scans became negative, two became equivocal, and two were unchanged; the presence and size of thrombus was constant by echocardiography in all seven patients. Of the six patients studied on aspirin plus dipyridamole, one platelet scan became negative, those of three became equivocal, and two were unchanged; all echocardiographic findings remained positive, but one patient had decreased thrombus size. Among four warfarin-treated patients, three had resolution of platelet deposition and one was unchanged; by echocardiography, thrombus resolved in one patient, was decreased in size in one, and was unchanged in two. We conclude that, in the absence of antithrombotic drug therapy, platelet imaging and echocardiographic findings are stable in patients with left ventricular thrombi not caused by recent myocardial infarction. Sulfinpyrazone, aspirin plus dipyridamole, and warfarin all interrupt platelet deposition in some patients with chronic left ventricular thrombi
-
Energy Technology Data Exchange (ETDEWEB)
Borges, Marcela Dias; Aguillera, André Haraguti [Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Brilhante, José Joaquim; Caixeta, Adriano [Hospital Israelita Albert Einstein, São Paulo, SP (Brazil)
2013-07-01
An eighty-year-old male patient with a history of prior (19 years) coronary artery bypass graft surgery was admitted to the hospital with non ST-segment elevation myocardial infarction (NSTEMI). During the hospital stay he was taking acetylsalicylic acid 100mg per day, a loading dose of 600mg clopidogrel, and low molecular weight heparin 1mg/kg twice a day. Twenty-four hours later the patient underwent coronary angiography, which showed a 90% obstruction in the mid portion of the saphenous vein graft to obtuse marginal with signs of degeneration and local thrombus (Figure 1). Thrombus aspiration was performed with a 6-Fr Export{sup ™} catheter (Medtronic, Santa Rosa, CA, USA), which removed small reddish colored fragments. They were fixed in 2,5% glutaraldehyde in a 0.1M sodium cacodilate buffer. The material was processed following the GOTO protocol in which the fragments were washed with osmium tetroxide and titanic acid, after which they were dried in a critical-point device and a golden bath. Scanning electron microscopy and high definition photos (3,000 to 27,221x magnification) were obtained by the FEI Quanta{sup ™} FEG SEM device (FEI Company, Hillsboro, OR, USA). The images showed that the thrombus was rich in activated platelets, with few erythrocytes or inflammatory cells. Many cholesterol crystals were observed (Figures 2 to). The fibrin networks were sparse and thin, which is compatible with a short ischemic time and recent thrombus formation.
-
International Nuclear Information System (INIS)
Borges, Marcela Dias; Aguillera, André Haraguti; Brilhante, José Joaquim; Caixeta, Adriano
2013-01-01
An eighty-year-old male patient with a history of prior (19 years) coronary artery bypass graft surgery was admitted to the hospital with non ST-segment elevation myocardial infarction (NSTEMI). During the hospital stay he was taking acetylsalicylic acid 100mg per day, a loading dose of 600mg clopidogrel, and low molecular weight heparin 1mg/kg twice a day. Twenty-four hours later the patient underwent coronary angiography, which showed a 90% obstruction in the mid portion of the saphenous vein graft to obtuse marginal with signs of degeneration and local thrombus (Figure 1). Thrombus aspiration was performed with a 6-Fr Export"™ catheter (Medtronic, Santa Rosa, CA, USA), which removed small reddish colored fragments. They were fixed in 2,5% glutaraldehyde in a 0.1M sodium cacodilate buffer. The material was processed following the GOTO protocol in which the fragments were washed with osmium tetroxide and titanic acid, after which they were dried in a critical-point device and a golden bath. Scanning electron microscopy and high definition photos (3,000 to 27,221x magnification) were obtained by the FEI Quanta"™ FEG SEM device (FEI Company, Hillsboro, OR, USA). The images showed that the thrombus was rich in activated platelets, with few erythrocytes or inflammatory cells. Many cholesterol crystals were observed (Figures 2 to). The fibrin networks were sparse and thin, which is compatible with a short ischemic time and recent thrombus formation
-
Yen, Ting-Lin; Lu, Wan-Jung; Lien, Li-Ming; Thomas, Philip Aloysius; Lee, Tzu-Yin; Chiu, Hou-Chang; Sheu, Joen-Rong; Lin, Kuan-Hung
2014-01-01
Amarogentin, an active principle of Gentiana lutea, possess antitumorigenic, antidiabetic, and antioxidative properties. Activation of platelets is associated with intravascular thrombosis and cardiovascular diseases. The present study examined the effects of amarogentin on platelet activation. Amarogentin treatment (15~60 μM) inhibited platelet aggregation induced by collagen, but not thrombin, arachidonic acid, and U46619. Amarogentin inhibited collagen-induced phosphorylation of phospholipase C (PLC) γ2, protein kinase C (PKC), and mitogen-activated protein kinases (MAPKs). It also inhibits in vivo thrombus formation in mice. In addition, neither the guanylate cyclase inhibitor ODQ nor the adenylate cyclase inhibitor SQ22536 affected the amarogentin-mediated inhibition of platelet aggregation, which suggests that amarogentin does not regulate the levels of cyclic AMP and cyclic GMP. In conclusion, amarogentin prevents platelet activation through the inhibition of PLC γ2-PKC cascade and MAPK pathway. Our findings suggest that amarogentin may offer therapeutic potential for preventing or treating thromboembolic disorders.
-
Numerical Simulation of Thrombotic Occlusion in Tortuous Arterioles
Feng, Zhi-Gang; Cortina, Miguel; Chesnutt, Jennifer KW; Han, Hai-Chao
2017-01-01
Tortuous microvessels alter blood flow and stimulate thrombosis but the physical mechanisms are poorly understood. Both tortuous microvessels and abnormally large platelets are seen in diabetic patients. Thus, the objective of this study was to determine the physical effects of arteriole tortuosity and platelet size on the microscale processes of thrombotic occlusion in microvessels. A new lattice-Boltzmann method-based discrete element model was developed to simulate the fluid flow field with fluid-platelet coupling, platelet interactions, thrombus formation, and thrombotic occlusion in tortuous arterioles. Our results show that vessel tortuosity creates high shear stress zones that activate platelets and stimulate thrombus formation. The growth rate depends on the level of tortuosity and the pressure and flow boundary conditions. Once thrombi began to form, platelet collisions with thrombi and subsequent activations were more important than tortuosity level. Thrombus growth narrowed the channel and reduced the flow rate. Larger platelet size leads to quicker decrease of flow rate due to larger thrombi that occluded the arteriole. This study elucidated the important roles that tortuosity and platelet size play in thrombus formation and occlusion in arterioles. PMID:29327739
-
DEFF Research Database (Denmark)
Grüner, Sabine; Prostredna, Miroslava; Schulte, Valerie
2003-01-01
by intravital fluorescence microscopy that platelet adhesion and thrombus growth on the exposed ECM of the injured carotid artery is not significantly altered in alpha2-null mice and even in mice with a Cre/loxP-mediated loss of all beta1 integrins on their platelets. In contrast, inhibition of alphaIIbbeta3...... integrin on platelets in wild-type mice blocked aggregate formation and reduced platelet adhesion by 60.0%. Strikingly, alphaIIbbeta3 inhibition had a comparable effect in alpha2-null mice, demonstrating that other receptors mediate shear-resistant adhesion in the absence of functional alpha2beta1...... and alphaIIbbeta3. These were identified to be alpha5beta1 and/or alpha6beta1 as alphaIIbbeta3 inhibition abrogated platelet adhesion in beta1-null mice. We conclude that shear-resistant platelet adhesion on the injured vessel wall in vivo is a highly integrated process involving multiple integrin...
-
Directory of Open Access Journals (Sweden)
Hideki Hayashi
Full Text Available Inflammation is a common denominator in chronic diseases of aging. Yet, how inflammation fuels these diseases remains unknown. Neutrophils are the primary leukocytes involved in the early phase of innate immunity and inflammation. As part of their anti-microbial defense, neutrophils form extracellular traps (NETs by releasing decondensed chromatin lined with cytotoxic proteins. NETs have been shown to induce tissue injury and thrombosis. Here, we demonstrated that Sirt3, a nicotinamide adenine dinucleotide (NAD+-dependent protein deacetylase, an enzyme linked to human longevity, was expressed in mouse neutrophils and platelets. Using Sirt3-/- mice as a model of accelerated aging, we investigated the effects of Sirt3 deficiency on NETosis and platelet function, aiming to detect enhancement of thrombosis. More mitochondrial reactive oxygen species (ROS were generated in neutrophils and platelets of Sirt3-/- mice compared to WT, when stimulated with a low concentration of phorbol 12-myristate 13-acetate (PMA and a high concentration of thrombin, respectively. There were no differences in in vitro NETosis, with or without stimulation. Platelet aggregation was mildly augmented in Sirt3-/- mice compared to WT mice, when stimulated with a low concentration of collagen. The effect of Sirt3 deficiency on platelet and neutrophil activation in vivo was examined by the venous thrombosis model of inferior vena cava stenosis. Elevation of plasma DNA concentration was observed after stenosis in both genotypes, but no difference was shown between the two genotypes. The systemic response to thrombosis was enhanced in Sirt3-/- mice with significantly elevated neutrophil count and reduced platelet count. However, no differences were observed in incidence of thrombus formation, thrombus weight and thrombin-antithrombin complex generation between WT and Sirt3-/- mice. We conclude that Sirt3 does not considerably impact NET formation, platelet function, or venous
-
Enhanced venous thrombus resolution in plasminogen activator inhibitor type-2 deficient mice.
Siefert, S A; Chabasse, C; Mukhopadhyay, S; Hoofnagle, M H; Strickland, D K; Sarkar, R; Antalis, T M
2014-10-01
The resolution of deep vein thrombosis requires an inflammatory response and mobilization of proteases, such as urokinase-type plasminogen activator (uPA) and matrix metalloproteinases (MMPs), to degrade the thrombus and remodel the injured vein wall. Plasminogen activator inhibitor type 2 (PAI-2) is a serine protease inhibitor (serpin) with unique immunosuppressive and cell survival properties that was originally identified as an inhibitor of uPA. To investigate the role of PAI-2 in venous thrombus formation and resolution. Venous thrombus resolution was compared in wild-type C57BL/6, PAI-2(-/-) , and PAI-1(-/-) mice using the stasis model of deep vein thrombosis. Formed thrombi were harvested, thrombus weights were recorded, and tissue was analyzed for uPA and MMP activities, PAI-1 expression, and the nature of inflammatory cell infiltration. We found that the absence of PAI-2 enhanced venous thrombus resolution, while thrombus formation was unaffected. Enhanced venous thrombus resolution in PAI-2(-/-) mice was associated with increased uPA activity and reduced levels of PAI-1, with no significant effect on MMP-2 and -9 activities. PAI-1 deficiency resulted in an increase in thrombus resolution similar to PAI-2 deficiency, but additionally reduced venous thrombus formation and altered MMP activity. PAI-2-deficient thrombi had increased levels of the neutrophil chemoattractant CXCL2, which was associated with early enhanced neutrophil recruitment. These data identify PAI-2 as a novel regulator of venous thrombus resolution, which modulates several pathways involving both inflammatory and uPA activity mechanisms, distinct from PAI-1. Further examination of these pathways may lead to potential therapeutic prospects in accelerating thrombus resolution. © 2014 International Society on Thrombosis and Haemostasis.
-
In vivo and in vitro methods to study platelet adhesion to the components of the vessel wall
International Nuclear Information System (INIS)
Cazenave, J.-P.
1979-01-01
The methods that are used to measure platelet adhesion can be divided in five groups: methods that use an aggregometer to measure platelet adhesion to collagen in the presence of EDTA; methods that use binding of radiolabeled collagen, affinity chromatography, or gel filtration; the morphometric method of Baumgartner that measures platelet interaction with the subendothelium of an aorta exposed to flow in an annular perfusion chamber; the quantitative isotopic measurement of platelet adhesion to collagen-coated surfaces and to subendothelium with the rotating probe device of Cazenave; and in vivo platelet adhesion to the subendothelium measured by the morphometric method or with platelets radiolabeled with 51 Cr or 111 In. With these methods it has been possible to study the factors (Ca 2+ ; VIII: von Willebrand factor; hemodynamic factors: red cells, shear rate; components of the vessel wall) governing platelet adhesion to subendothelium and to collagen. It has also been possible to screen and study drugs inhibiting platelet adhesion, which is the first step in the formation of a thrombus at the site of vascular injury [fr
-
Quantitation of thrombogenicity of hemodialyzer with technetium-99m and indium-111 labeled platelets
International Nuclear Information System (INIS)
Dewanjee, M.K.; Kapadvanjwala, Mansoor; Ruzius, Kees; Serafini, A.N.; Zilleruelo, G.E.; Sfakianakis, G.N.
1993-01-01
The platelet thromobogenicity of a hemodialyzer was quantified with 99m Tc- and 111 In-labeled platelets. The platelets collected from blood of Beagle dogs, Yorkshire pigs and human volunteers were labeled with 111 in-tropolone (detergent-free) and 99m Tc-HMPAO. Hemodialysis was performed with a hollow-fiber dialyzer (HFD) in a flow-loop, the temperature of which was maintained at 37 o C, with flow-rates of 7, 150 and 270 mL/min; after dialysis, the HFD radioactivity was measured with an ionization chamber and imaged with a γ-camera. The radioactivity of samples of hollow-fibers taken from the top, middle and bottom of the dialyzer was determined with a γ-counter. The mean values of hemodialyzer-adherent platelet radioactivity were calculated for both radionuclides. The canine platelets were found to be more thrombogenic than porcine and human platelets. The adhesivity of porcine platelets to the biomaterial (cellulose-acetate) of the dialyzer approximated that of human platelets. The 99m Tc label underestimated the thrombus formation (P 111 In- and 99m Tc-labeled platelets suggests that both radionuclides could be used for measurement of device-induced thrombogenicity and may provide an estimation of prosthesis-induced thrombogenicity of human platelets from animal studies. (Author)
-
Directory of Open Access Journals (Sweden)
Joris M Niesten
Full Text Available INTRODUCTION: We related composition of cerebral thrombi to stroke subtype and attenuation on non-contrast CT (NCCT to gain more insight in etiopathogenesis and to validate thrombus attenuation as a new imaging biomarker for acute stroke. METHODS: We histopathologically investigated 22 thrombi retrieved after mechanical thrombectomy in acute stroke patients. First, thrombi were classified as fresh, lytic or organized. Second, percentages of red blood cells (RBCs, platelets and fibrin and number of red, white (respectively RBCs or platelets outnumbering other components with ≥ 15% or mixed thrombi were compared between large artery atherosclerosis (LAA, cardioembolism, dissection and unknown subtype. Third, correlation between attenuation and RBCs, platelets and fibrin was calculated using Pearson's correlation coefficients (r. RESULTS: Thrombi were fresh in 73% (n = 16, lytic in 18% (n = 4 and organized in 9% (n = 2. The stroke cause was LAA in eight (36%, cardioembolism in six (27%, dissection in three (14%, and unknown in five (23% patients. LAA thrombi showed the highest percentage RBCs (median 50 (range 35-90, followed by dissection (35 (20-40, p = 0.05, cardioembolism (35 (5-45, p = 0.013 and unknown subtype (25 (2-40, p = 0.006. No differences in platelets (p = 0.16 and fibrin (p = 0.52 between subtypes were found. LAA thrombi were classified as red or mixed (both n = 4, cardioembolisms as mixed (n = 5 or white (n = 1 and dissection as mixed (n = 3. There was a moderate positive correlation between attenuation and RBCs (r = 0.401, p = 0.049, and weak negative correlations with platelets (r = -0.368, p = 0.09 and fibrin (r = -0.073, p = 0.75. CONCLUSIONS: The majority of cerebral thrombi is fresh. There are no differences in age of thrombi between subtypes. LAA thrombi have highest percentages RBCs, cardioembolism and unknown subtype lowest. No relationship exists between subtype and platelets or fibrin percentages. We found a
-
Deposition of Fibrinogen on the Surface of in vitro Thrombi Prevents Platelet Adhesion
Owaynat, Hadil; Yermolenko, Ivan S.; Turaga, Ramya; Lishko, Valeryi K.; Sheller, Michael R.; Ugarova, Tatiana P.
2015-01-01
The initial accumulation of platelets after vessel injury is followed by thrombin-mediated generation of fibrin which is deposited around the plug. While numerous in vitro studies have shown that fibrin is highly adhesive for platelets, the surface of experimental thrombi in vivo contains very few platelets suggesting the existence of natural anti-adhesive mechanisms protecting stabilized thrombi from platelet accumulation and continuous thrombus propagation. We previously showed that adsorpt...
-
Iodine-125 metaraminol: A new platelet specific labeling agent
International Nuclear Information System (INIS)
Ohmomo, Y.; Yokoyama, A.; Kawaii, K.; Horiuchi, K.; Saji, H.; Torizuka, K.
1984-01-01
In the search for a platelet specific labeling agent, Metaraminol (MA), which is a sympatomimetic amine used for the treatment of hypotension, cardiogenic shock and well recognized as a drug actively incorporated and accumulated in platelet, attracted the authors' attention. Using the classical chloramine-T iodination method, a high labeling efficiency near 98%, reaching a specific activity up to about 1000 Ci/mmole was obtained. Upon the harvest of platelet, only as platelet rich plasma (PRP), the labeling with this radiopharmaceutical was easily performed by incubation at 37 0 C for 10 min. Labeling efficiency as high as 63.0 +- 3.1% at 24 x 10/sup 8/ cells/ml was obtained. In in-vitro studies, the unaltered state of I-125 MA labeled platelet, with their cellular functions fully retained was demonstrated. Pharmacological study indicated a specific incorporation of I-125 MA by active transport system similar to that of 5-HT, along with passive diffusion. Then the in-vivo study carried out in rabbits with induced thrombi on the femoral artery, showed rather rapid disappearance of the I-125 MA labeled autologous platelet radioactivity, from circulating blood reaching as high thrombus-to-blood activity ratio as 19.8+-4.3 within 30 min post-administration. This new platelet labeling agent, I-125 MA, has many advantages over the use of IN-111 oxine and holds considerable promise for thrombus imaging with single photon emission CT upon the availability of I-123 MA
-
Directory of Open Access Journals (Sweden)
Chase W Kessinger
Full Text Available Despite anticoagulation therapy, up to one-half of patients with deep vein thrombosis (DVT will develop the post-thrombotic syndrome (PTS. Improving the long-term outcome of DVT patients at risk for PTS will therefore require new approaches. Here we investigate the effects of statins--lipid-lowering agents with anti-thrombotic and anti-inflammatory properties--in decreasing thrombus burden and decreasing vein wall injury, mediators of PTS, in established murine stasis and non-stasis chemical-induced venous thrombosis (N = 282 mice. Treatment of mice with daily atorvastatin or rosuvastatin significantly reduced stasis venous thrombus burden by 25% without affecting lipid levels, blood coagulation parameters, or blood cell counts. Statin-driven reductions in VT burden (thrombus mass for stasis thrombi, intravital microscopy thrombus area for non-stasis thrombi compared similarly to the therapeutic anticoagulant effects of low molecular weight heparin. Blood from statin-treated mice showed significant reductions in platelet aggregation and clot stability. Statins additionally reduced thrombus plasminogen activator inhibitor-1 (PAI-1, tissue factor, neutrophils, myeloperoxidase, neutrophil extracellular traps (NETs, and macrophages, and these effects were most notable in the earlier timepoints after DVT formation. In addition, statins reduced DVT-induced vein wall scarring by 50% durably up to day 21 in stasis VT, as shown by polarized light microscopy of picrosirius red-stained vein wall collagen. The overall results demonstrate that statins improve VT resolution via profibrinolytic, anticoagulant, antiplatelet, and anti-vein wall scarring effects. Statins may therefore offer a new pharmacotherapeutic approach to improve DVT resolution and to reduce the post-thrombotic syndrome, particularly in subjects who are ineligible for anticoagulation therapy.
-
Kessinger, Chase W; Kim, Jin Won; Henke, Peter K; Thompson, Brian; McCarthy, Jason R; Hara, Tetsuya; Sillesen, Martin; Margey, Ronan J P; Libby, Peter; Weissleder, Ralph; Lin, Charles P; Jaffer, Farouc A
2015-01-01
Despite anticoagulation therapy, up to one-half of patients with deep vein thrombosis (DVT) will develop the post-thrombotic syndrome (PTS). Improving the long-term outcome of DVT patients at risk for PTS will therefore require new approaches. Here we investigate the effects of statins--lipid-lowering agents with anti-thrombotic and anti-inflammatory properties--in decreasing thrombus burden and decreasing vein wall injury, mediators of PTS, in established murine stasis and non-stasis chemical-induced venous thrombosis (N = 282 mice). Treatment of mice with daily atorvastatin or rosuvastatin significantly reduced stasis venous thrombus burden by 25% without affecting lipid levels, blood coagulation parameters, or blood cell counts. Statin-driven reductions in VT burden (thrombus mass for stasis thrombi, intravital microscopy thrombus area for non-stasis thrombi) compared similarly to the therapeutic anticoagulant effects of low molecular weight heparin. Blood from statin-treated mice showed significant reductions in platelet aggregation and clot stability. Statins additionally reduced thrombus plasminogen activator inhibitor-1 (PAI-1), tissue factor, neutrophils, myeloperoxidase, neutrophil extracellular traps (NETs), and macrophages, and these effects were most notable in the earlier timepoints after DVT formation. In addition, statins reduced DVT-induced vein wall scarring by 50% durably up to day 21 in stasis VT, as shown by polarized light microscopy of picrosirius red-stained vein wall collagen. The overall results demonstrate that statins improve VT resolution via profibrinolytic, anticoagulant, antiplatelet, and anti-vein wall scarring effects. Statins may therefore offer a new pharmacotherapeutic approach to improve DVT resolution and to reduce the post-thrombotic syndrome, particularly in subjects who are ineligible for anticoagulation therapy.
-
Wilson-Nieuwenhuis, Joels S T; Dempsey-Hibbert, Nina; Liauw, Christopher M; Whitehead, Kathryn A
2017-12-01
Bacterial contamination of blood products poses a major risk in transfusion medicine, including transfusions involving platelet products. Although testing systems are in place for routine screening of platelet units, the formation of bacterial biofilms in such units may decrease the likelihood that bacteria will be detected. This work determined the surface properties of p-PVC platelet concentrate bags and investigated how these characteristics influenced biofilm formation. Serratia marcescens and Staphylococcus epidermidis, two species commonly implicated in platelet contamination, were used to study biofilm growth. The platelet concentrate bags were physically flattened to determine if reducing the surface roughness altered biofilm formation. The results demonstrated that the flattening process of the platelet bags affected the chemistry of the surface and reduced the surface hydrophobicity. Flattening of the surfaces resulted in a reduction in biofilm formation for both species after 5 days, with S. marcescens demonstrating a greater reduction. However, there was no significant difference between the smooth and flat surfaces following 7 days' incubation for S. marcescens and no significant differences between any of the surfaces following 7 days' incubation for S. epidermidis. The results suggest that flattening the p-PVC surfaces may limit potential biofilm formation for the current duration of platelet storage time of 5 days. It is hoped that this work will enhance the understanding of how surface properties influence the development of microbial biofilms in platelet concentrate bags in order to devise a solution to discourage biofilm formation. Copyright © 2017 Elsevier B.V. All rights reserved.
-
Radiopharmaceuticals for thrombus detection
International Nuclear Information System (INIS)
Knight, L.C.
1990-01-01
Most of the components of the thrombotic and fibrinolytic systems have at some time been evaluated as a means of carrying a radiolabel specifically to thrombi, although very few have been promising enough to emerge from investigational status to routine clinical use. New approaches are being explored, including improved methods of labeling platelets, chemically modified forms of previously tested plasma proteins, and new biomolecules, including monoclonal antibodies specific for fibrin and platelets. The current goal is to find one or more radiotracers that bind specifically and rapidly to thrombi, and that also have a rapid blood disappearance rate, permitting a clear diagnosis within a few hours after injection. Because this test may be needed to assess the course of therapy in an anticoagulated patient, the ideal radiopharmaceutical should be able to locate thrombi without interference by anticoagulants. Until a suitable thrombus-specific radiopharmaceutical becomes generally available, many hospitals will continue to attempt to make a diagnosis with nonspecific radiopharmaceuticals that can at best provide blood pool images to indicate filling defects. Several of the new approaches seem likely to provide the radiopharmaceutical sought, although clinical trials are at an early stage.137 references
-
Three-dimentional simulation of flow-induced platelet activation in artificial heart valves
Hedayat, Mohammadali; Asgharzadeh, Hafez; Borazjani, Iman
2015-11-01
Since the advent of heart valve, several valve types such as mechanical and bio-prosthetic valves have been designed. Mechanical Heart Valves (MHV) are durable but suffer from thromboembolic complications that caused by shear-induced platelet activation near the valve region. Bio-prosthetic Heart Valves (BHV) are known for better hemodynamics. However, they usually have a short average life time. Realistic simulations of heart valves in combination with platelet activation models can lead to a better understanding of the potential risk of thrombus formation in such devices. In this study, an Eulerian approach is developed to calculate the platelet activation in three-dimensional simulations of flow through MHV and BHV using a parallel overset-curvilinear immersed boundary technique. A curvilinear body-fitted grid is used for the flow simulation through the anatomic aorta, while the sharp-interface immersed boundary method is used for simulation of the Left Ventricle (LV) with prescribed motion. In addition, dynamics of valves were calculated numerically using under-relaxed strong-coupling algorithm. Finally, the platelet activation results for BMV and MHV are compared with each other.
-
International Nuclear Information System (INIS)
Vandenberg, B.F.; Seabold, J.E.; Conrad, G.R.; Kieso, R.; Johnson, J.; Fox-Eastham, K.; Ponto, J.; Bruch, P.; Kerber, R.E.
1988-01-01
111In-labeled platelet scintigraphy and two-dimensional echocardiography were performed in 40 dogs to determine the ability of the two techniques to detect left atrial appendage thrombi. Thrombi were induced in 33 dogs that were classified into two groups, acute or chronic, according to the time of labeled-platelet injection after thrombus induction. In the acute group (17 dogs), platelets were injected 24 hours after thrombus induction. In the chronic group (16 dogs), platelets were injected 4-8 days after thrombus induction. Sham thoracotomies were performed on seven additional control dogs who did not receive thrombin injections. Analog and blood pool-corrected 111In-labeled platelet scintigraphy images were obtained 4-72 hours later. Closed-chest two-dimensional echocardiography was performed before thoracotomy and repeated at the time of scintigraphy. The location and size of each thrombus were verified at autopsy. Two-dimensional echocardiography detected three of 17 acute (mean volume, 1.2 +/- 1.0 cc) and three of 10 chronic (mean volume, 0.4 +/- 0.3 cc; p less than 0.025) left atrial appendage thrombi. 111In-labeled platelet scintigraphy detected all 17 acute thrombi but only two of 10 chronic thrombi. The measured radioactivity levels of the excised thrombi were 1,949 +/- 1,665 cpm/clot/dose in group 1 and 228 +/- 213 cpm/clot/dose in group 2 (p less than 0.005). In this model, 111In-labeled platelet scintigraphy was able to detect acute left atrial appendage thrombi that could not be identified by two-dimensional echocardiography. Both techniques showed poor sensitivity for detection of chronic thrombi. The decline in sensitivity of 111In-labeled platelet scintigraphy for detection of older thrombi is probably due to diminished labeled-platelet incorporation
-
[125I] radioiodinated metaraminol: A new platelet-specific labeling agent
International Nuclear Information System (INIS)
Ohmomo, Y.; Yokoyama, A.; Kawai, K.; Arano, Y.; Horiuchi, K.; Saji, H.; Torizuka, K.
1985-01-01
In our search for a platelet-specific labeling agent, metaraminol (MA), a low-toxic pharmaceutical for the treatment of hypotension and cardiogenic shock, attracted our attention. Its active incorporation and accumulation by platelets have been recognized. At first, the preparation of 125 I radioiodinated metaraminol ( 125 I-MA) was carried out using the chloramine-T method. Then, upon the harvest of platelets as platelet-rich plasma (PRP), their labeling with this new radiopharmaceutical was easily performed by incubation for 10 min at 37 0 C. The cell-labeling efficiency was dependent on cell density, reaching 63.0%+-3.1% at 2.4x10 9 cells/ml. The specific incorporation of 125 I-MA by an active transport system similar to that of 5-hydroxytryptamine (5-HT) as well as by passive diffusion was demonstrated. In vitro studies, the unaltered state of 125 I-MA-labeled platelets with their cellular functions fully retained was estimated. In vivo studies carried out in rabbits with induced thrombi in the femoral artery showed a rather rapid disappearance of the radioactivity from circulating blood, reaching a high thrombus-to-blood activity ratio of 19.8+-4.3 within 30 min of the administration of 125 I-MA-labeled autologous platelets. Thus, with the potential availability of 123 I, 123 I-MA-labeled platelets appear to be a promising agent for thrombus imaging using single-emission computed tomography (CT) studies. (orig.)
-
Platelet microparticle-inspired clot-responsive nanomedicine for targeted fibrinolysis.
Pawlowski, Christa L; Li, Wei; Sun, Michael; Ravichandran, Kavya; Hickman, DaShawn; Kos, Clarissa; Kaur, Gurbani; Sen Gupta, Anirban
2017-06-01
Intravascular administration of plasminogen activators is a clinically important thrombolytic strategy to treat occlusive vascular conditions. A major issue with this strategy is the systemic off-target drug action, which affects hemostatic capabilities and causes substantial hemorrhagic risks. This issue can be potentially resolved by designing technologies that allow thrombus-targeted delivery and site-specific action of thrombolytic drugs. To this end, leveraging a liposomal platform, we have developed platelet microparticle (PMP)-inspired nanovesicles (PMINs), that can protect encapsulated thrombolytic drugs in circulation to prevent off-target uptake and action, anchor actively onto thrombus via PMP-relevant molecular mechanisms and allow drug release via thrombus-relevant enzymatic trigger. Specifically, the PMINs can anchor onto thrombus via heteromultivalent ligand-mediated binding to active platelet integrin GPIIb-IIIa and P-selectin, and release the thrombolytic payload due to vesicle destabilization triggered by clot-relevant enzyme phospholipase-A 2 . Here we report on the evaluation of clot-targeting efficacy, lipase-triggered drug release and resultant thrombolytic capability of the PMINs in vitro, and subsequently demonstrate that intravenous delivery of thrombolytic-loaded PMINs can render targeted fibrinolysis without affecting systemic hemostasis, in vivo, in a carotid artery thrombosis model in mice. Our studies establish significant promise of the PMIN technology for safe and site-targeted nanomedicine therapies in the vascular compartment. Copyright © 2017. Published by Elsevier Ltd.
-
Biasetti, Jacopo; Spazzini, Pier Giorgio; Swedenborg, Jesper; Gasser, T Christian
2012-01-01
Abdominal Aortic Aneurysms (AAAs) are frequently characterized by the presence of an Intra-Luminal Thrombus (ILT) known to influence their evolution biochemically and biomechanically. The ILT progression mechanism is still unclear and little is known regarding the impact of the chemical species transported by blood flow on this mechanism. Chemical agonists and antagonists of platelets activation, aggregation, and adhesion and the proteins involved in the coagulation cascade (CC) may play an important role in ILT development. Starting from this assumption, the evolution of chemical species involved in the CC, their relation to coherent vortical structures (VSs) and their possible effect on ILT evolution have been studied. To this end a fluid-chemical model that simulates the CC through a series of convection-diffusion-reaction (CDR) equations has been developed. The model involves plasma-phase and surface-bound enzymes and zymogens, and includes both plasma-phase and membrane-phase reactions. Blood is modeled as a non-Newtonian incompressible fluid. VSs convect thrombin in the domain and lead to the high concentration observed in the distal portion of the AAA. This finding is in line with the clinical observations showing that the thickest ILT is usually seen in the distal AAA region. The proposed model, due to its ability to couple the fluid and chemical domains, provides an integrated mechanochemical picture that potentially could help unveil mechanisms of ILT formation and development.
-
International Nuclear Information System (INIS)
Fedullo, P.F.; Moser, K.M.; Moser, K.S.; Konopka, R.; Hartman, M.T.
1982-01-01
The goal of heparin thepapy in deep vein thrombosis is to prevent thrombus extension. The relationship between thrombus extension and the results of coagulation tests used to monitor heparin thepapy is unclear. To expose this relationship, we studied the effect of several heparin regimens on the accretion of indium-111-labeled platelets on fresh venous thrombi, as detected by gamma imaging, and monitored the activated partial thromboplastin time (APTT). Six dogs were treated with a 300-U/kg bolus of heparin followed by a 90-U/kg/hour heparin infusion, a dose of heparin sufficient to increase the APTT to levels greater than eight times baseline (APTT ratio); platelet accretion (thrombus imaging) occurred only after the heparin effect was reversed with protamine sulfate. Nineteen dogs were treated with a 150-U/kg bolus of heparin followed by a 4-hour, 45-U/kg/hour heparin infusion; a thrombus was demonstrated only after protamine injection in 12 (mean APTT ratio 1.3 +/- 0.19) and before protamine injection in seven. In thirteen of these 19 dogs, 30 minutes separated the platelet injection from heparin therapy, while in six this duration was less than 30 minutes. In four of these six dogs, thrombi were demonstrated before protamine therapy and at APTT ratios greater than 3.0. Finally, 10 dogs were treated with a 100-U/kg bolus followed by a 3-hour, 50-U/kg/hour heparin infusion, after which the APTT was allowed to return to baseline values spontaneously. In all 10 dogs, a thrombus was demonstrated only after cessation of the heparin infusion, and at a mean APTT ratio of 1.4 +/- 0.15 times baseline. These results suggest that, except with very early platelet injection, platelet accretion by thrombi is consistently inhibited by heparin at APTT ratios greater than 2.5
-
Potential application of labeled antibodies for thrombus detection
Energy Technology Data Exchange (ETDEWEB)
Ezekowitz, M.D.; Coller, B.S.; Srivastava, S.C.
1986-01-01
Labeling platelets with monoclonal antibodies in whole blood for imaging thrombi is less cumbersome than the established /sup 111/In-oxine method. 7E3, a murine monoclonal antibody directed against glycoprotein IIb and/or IIIa on both human and dog platelets was used to label canine platelets. Thrombi were induced by transcatheter placement of a copper coil followed by electrocoagulation. 7E3 was iodinated with /sup 131/I and labelled with /sup 111/In using 7E3-DTPA conjugate. Whole blood was incubated with 0.5 - 1.0 ..mu..g labeled 7E3/mL blood. In 4/4 dogs, experimental deep vein thrombi were identified using both /sup 131/I-and /sup 111/In-labeled 7E3 within 5-30 min after injection. For both isotopes, 1 h blood clearance was 54 + - 9%. In 1/3 dogs, experimental coronary thrombus could be identified ex vivo at 4 h. Clot to blood ratios ranged between 7 to 13:1. Using the /sup 111/In-oxine method, 0/3 coronary thrombi were seen. Thus, /sup 131/I-and /sup 111/In-labeled 7E3 may be used to readily identify peripheral venous thrombi. For reliable and prompt identification of coronary thrombi, more rapid clearance of the labeled platelets is required.
-
International Nuclear Information System (INIS)
Yui, Tokuo
1981-01-01
Fundamental study: Factors influencing the labeling on human platelets were evaluated and optimal labeling conditions were chosen. Then, platelet survival times were measured and organ distribution of labeled platelets was observed in rat by four different methods. These results were compared with each other. Based on the findings of those studies, the protocol of human platelet labeling with 111 In-oxine for clinical use was established. Clinical study: In normal cases, a platelet survival time and a platelet turnover rate were quite similar to the results from 51 Cr method. In gamma camera imaging, a radioactivity on the heart decreased with the lapse of time, while that on the spleen and liver gradually increased. In patients with idiopathic thrombocytopenic purpura, platelet survival time was markedly shortened and both a platelet turnover rate and an effective production increased. In patient with congestive splenomegaly, a platelet survival time was normal, whereas a platelet pooling on the spleen markedly increased. In patients who were implanted dacron-graft for abdominal aortic aneurysm, a radioactivity accumulated to the graft and a platelet survival time shortened. In a patient with myocardial infarction, the camera imaging clearly showed the thrombus in the left ventricular aneurysm. In three patients with mitral stenosis, thrombi in left atrium were observed at the camera images. Imaging of a platelet distribution and measurement of platelet survival time using 111 In-oxine labeled platelets are considered to be an excellent method for the diagnosis and decision of treatment on various disorders with thrombocytopenia and thrombosis. (J.P.N.)
-
The impact of night-shift work on platelet function in healthy medical staff.
Nakao, Tomoko; Yasumoto, Atsushi; Tokuoka, Suzumi; Kita, Yoshihiro; Kawahara, Takuya; Daimon, Masao; Yatomi, Yutaka
2018-04-18
Rotating shift work has been reported to increase the risk of cardiovascular diseases. Vascular endothelial dysfunction and platelet activation are among the leading causes of thrombus formation in patients with myocardial infarction or stroke. Endothelial function has been shown to be impaired immediately after night-shift work; however, it is not known whether platelets are also activated. The aim of this study was to investigate the acute impact of night-shift work on platelet function. This observational study included 11 healthy medical staff members (seven women, median age 32 years). We examined each subject's platelet aggregation rates and the serum concentrations of eicosanoid mediators after night-shift work and on day-shift work without preceding night-shift work (baseline). Platelet aggregation did not differ from baseline levels after night-shift work. However, serum cyclooxygenase (COX)-metabolized eicosanoid mediators, particularly thromboxane (Tx) B 2 (a stable metabolite of TxA 2 and the most important marker of platelet activation), were significantly higher after the night-shift than at baseline (median 65.3 vs 180.4 ng/ml). Although platelet aggregation did not increase, there was an increase in serum COX-metabolized eicosanoid mediators such as TxB 2 in healthy medical staff after night-shift work. This platelet hypersensitivity may be one of the mechanisms underlying the significant association between night-shift work and adverse cardiovascular outcomes.
-
Regulator of G-protein signaling 18 controls both platelet generation and function.
Directory of Open Access Journals (Sweden)
Nathalie Delesque-Touchard
Full Text Available RGS18 is a myeloerythroid lineage-specific regulator of G-protein signaling, highly expressed in megakaryocytes (MKs and platelets. In the present study, we describe the first generation of a RGS18 knockout mouse model (RGS18-/-. Interesting phenotypic differences between RGS18-/- and wild-type (WT mice were identified, and show that RGS18 plays a significant role in both platelet generation and function. RGS18 deficiency produced a gain of function phenotype in platelets. In resting platelets, the level of CD62P expression was increased in RGS18-/- mice. This increase correlated with a higher level of plasmatic serotonin concentration. RGS18-/- platelets displayed a higher sensitivity to activation in vitro. RGS18 deficiency markedly increased thrombus formation in vivo. In addition, RGS18-/- mice presented a mild thrombocytopenia, accompanied with a marked deficit in MK number in the bone marrow. Analysis of MK maturation in vitro and in vivo revealed a defective megakaryopoiesis in RGS18-/- mice, with a lower bone marrow content of only the most committed MK precursors. Finally, RGS18 deficiency was correlated to a defect of platelet recovery in vivo under acute conditions of thrombocytopenia. Thus, we highlight a role for RGS18 in platelet generation and function, and provide additional insights into the physiology of RGS18.
-
International Nuclear Information System (INIS)
Fedullo, P.F.; Moser, K.M.; Moser, K.S.; Konopka, R.; Hartman, M.T.
1982-01-01
The goal of heparin therapy in deep vein thrombosis is to prevent thrombus extension. The relationship between thrombus extension and the results of coagulation tests used to monitor heparin therapy is unclear. To explore this relationship, we studied the effect of several heparin regimens on the accretion of 111 In-labeled platelets on fresh venous thrombi, as detected by gamma imaging, and monitored the activated partial thromboplastin time (APTT). Six dogs were treated with a 300-U/kg bolus of heparin followed by a 90-U/kg/hour heparin infusion, a dose of heparin sufficient to increase the APTT to levels greater than eight times baseline (APTT ratio); platelet accretion (thrombus imaging) occurred only after the heparin effect was reversed with protamine sulfate. Nineteen dogs were treated with a 150-U/kg bolus of heparin followed by a 4-hour, 45-U/kg/hour heparin infusion; a thrombus was demonstrated only after protamine injection in 12 (mean APTT ratio 1.3 +/- 0.19) and before protamine injection in seven. In thirteen of these 19 dogs, 30 minutes separated the platelet injection from heparin therapy, while in six this duration was less than 30 minutes. In four of these six dogs, thrombi were demonstrated before protamine therapy and at APTT ratios greater than 3.0. Finally, 10 dogs were treated with a 100-U/kg bolus followed by a 3-hour, 50-U/kg/hour heparin infusion, after which the APTT was allowed to return to baseline values spontaneously. In all 10 dogs, a thrombus was demonstrated only after cessation of the heparin infusion, and at a mean APTT ratio of 1.4 +/- 0.15 times baseline. These results suggest that, except with very early platelet injection, platelet accretion by thrombi is consistently inhibited by heparin at APTT ratios greater than 2.5. Platelet accretion by venous thrombi occurs within narrow limits of heparin effect as reflected by the APTT
-
Deep venous thrombus characterization: ultrasonography, elastography and scattering operator
Thibaud Berthomier; Ali Mansour; Luc Bressollette; Frédéric Le Roy; Dominique Mottier
2017-01-01
A thrombus or a blood clot is the result of blood coagulation which is a natural process to prevent bleeding. An inappropriate formation of a thrombus in a deep vein is known as Deep Venous Thrombosis (DVT). The main complication of a DVT is a Pulmonary Embolism (PE) which occurs when a thrombus breaks loose and travels to the lungs. DVT, PE, or both are also known as Venous thromboembolism (VTE). It affects an estimated 300,000–600,000 Individuals just in the United States per year and can c...
-
Platelet glycoprotein VI binds to polymerized fibrin and promotes thrombin generation.
Mammadova-Bach, Elmina; Ollivier, Véronique; Loyau, Stéphane; Schaff, Mathieu; Dumont, Bénédicte; Favier, Rémi; Freyburger, Geneviève; Latger-Cannard, Véronique; Nieswandt, Bernhard; Gachet, Christian; Mangin, Pierre H; Jandrot-Perrus, Martine
2015-07-30
Fibrin, the coagulation end product, consolidates the platelet plug at sites of vascular injury and supports the recruitment of circulating platelets. In addition to integrin αIIbβ3, another as-yet-unidentified receptor is thought to mediate platelet interaction with fibrin. Platelet glycoprotein VI (GPVI) interacts with collagen and several other adhesive macromolecules. We evaluated the hypothesis that GPVI could be a functional platelet receptor for fibrin. Calibrated thrombin assays using platelet-rich plasma (PRP) showed that tissue factor-triggered thrombin generation was impaired in GPVI-deficient patients and reduced by the anti-GPVI Fab 9O12. Assays on reconstituted PRP and PRP from fibrinogen-deficient patients revealed a fibrinogen-dependent enhancement of thrombin generation, which relied on functional GPVI. The effect of GPVI was found to depend on fibrin polymerization. A binding assay showed a specific interaction between GPVI-Fc and fibrin, inhibited by the Fab 9O12. This Fab also reduced platelet adhesion to fibrin at low (300 s(-1)) and high (1500 s(-1)) wall shear rates. Platelets adherent to fibrin displayed shape change, exposure of procoagulant phospholipids, and the formation of small clots. When hirudinated blood was perfused at 1500 s(-1) over preformed fibrin-rich clots, the Fab 9O12 decreased the recruitment of platelets by up to 85%. This study identifies GPVI as a platelet receptor for polymerized fibrin with 2 major functions: (1) amplification of thrombin generation and (2) recruitment of circulating platelets to clots. These so-far-unrecognized properties of GPVI confer on it a key role in thrombus growth and stabilization. © 2015 by The American Society of Hematology.
-
Schulz, C; von Brühl, M-L; Barocke, V; Cullen, P; Mayer, K; Okrojek, R; Steinhart, A; Ahmad, Z; Kremmer, E; Nieswandt, B; Frampton, J; Massberg, S; Schmidt, R
2011-05-01
Platelets play a central role in hemostasis, in inflammatory diseases such as atherosclerosis, and during thrombus formation following vascular injury. Thereby, platelets interact intensively with monocytes and enhance their recruitment to the vascular wall. To investigate the role of the extracellular matrix metalloproteinase inducer (EMMPRIN) in platelet-monocyte interactions. Isolated human monocytes were perfused in vitro over firmly adherent platelets to allow investigation of the role of EMMPRIN in platelet-monocyte interactions under flow conditions. Monocytes readily bound to surface-adherent platelets. Both antibody blockade and gene silencing of monocyte EMMPRIN substantially attenuated firm adhesion of monocytes to platelets at arterial and venous shear rates. In vivo, platelet interactions with the murine monocyte cell line ANA-1 were significantly decreased when ANA-1 cells were pretreated with EMMPRIN-silencing small interfering RNA prior to injection into wild-type mice. Using intravital microscopy, we showed that recruitment of EMMPRIN-silenced ANA-1 to the injured carotid artery was significantly reduced as compared with control cells. Further silencing of EMMPRIN resulted in significantly fewer ANA-1-platelet aggregates in the mouse circulation as determined by flow cytometry. Finally, we identified glycoprotein (GP)VI as a critical corresponding receptor on platelets that mediates interaction with monocyte EMMPRIN. Thus, blocking of GPVI inhibited the effect of EMMPRIN on firm monocyte adhesion to platelets under arterial flow conditions in vitro, and abrogated EMMPRIN-mediated platelet-monocyte aggregate formation in vivo. EMMPRIN supports platelet-monocyte interactions and promotes monocyte recruitment to the arterial wall. Therefore, EMMPRIN might represent a novel target to reduce vascular inflammation and atherosclerotic lesion development. © 2011 International Society on Thrombosis and Haemostasis.
-
Rhee, Man Hee; Sung, Yoon-Young; Yang, Won-Kyung; Kim, Seung Hyung; Kim, Ho-Kyoung
2014-01-01
Ethnopharmacological Relevance. Morus alba L. leaves (MAE) have been used in fork medicine for the treatment of beriberi, edema, diabetes, hypertension, and atherosclerosis. However, underlying mechanism of MAE on cardiovascular protection remains to be elucidated. Therefore, we investigated whether MAE affect platelet aggregation and thrombosis. Materials and Methods. The anti-platelet activity of MAE was studied using rat platelets. The extent of anti-platelet activity of MAE was assayed in collagen-induced platelet aggregation. ATP and serotonin release was carried out. The activation of integrin α IIb β 3 and phosphorylation of signaling molecules, including MAPK and Akt, were investigated with cytofluorometer and immunoblotting, respectively. The thrombus formation in vivo was also evaluated in arteriovenous shunt model of rats. Results. HPLC chromatographic analysis revealed that MAE contained rutin and isoquercetin. MAE dose-dependently inhibited collagen-induced platelet aggregation. MAE also attenuated serotonin secretion and thromboxane A2 formation. In addition, the extract in vivo activity showed that MAE at 100, 200, and 400 mg/kg significantly and dose-dependently attenuated thrombus formation in rat arterio-venous shunt model by 52.3% (P < 0.001), 28.3% (P < 0.01), and 19.1% (P < 0.05), respectively. Conclusions. MAE inhibit platelet activation, TXB2 formation, serotonin secretion, aggregation, and thrombus formation. The plant extract could be considered as a candidate to anti-platelet and antithrombotic agent. PMID:24701244
-
Jang, Ji Yong; Wang, Su Bin; Min, Ji Hyun; Chae, Yun Hee; Baek, Jin Young; Yu, Dae-Yeul; Chang, Tong-Shin
2015-05-01
Collagen-induced platelet signaling is mediated by binding to the primary receptor glycoprotein VI (GPVI). Reactive oxygen species produced in response to collagen have been found to be responsible for the propagation of GPVI signaling pathways in platelets. Therefore, it has been suggested that antioxidant enzymes could down-regulate GPVI-stimulated platelet activation. Although the antioxidant enzyme peroxiredoxin II (PrxII) has emerged as having a role in negatively regulating signaling through various receptors by eliminating H2O2 generated upon receptor stimulation, the function of PrxII in collagen-stimulated platelets is not known. We tested the hypothesis that PrxII negatively regulates collagen-stimulated platelet activation. We analyzed PrxII-deficient murine platelets. PrxII deficiency enhanced GPVI-mediated platelet activation through the defective elimination of H2O2 and the impaired protection of SH2 domain-containing tyrosine phosphatase 2 (SHP-2) against oxidative inactivation, which resulted in increased tyrosine phosphorylation of key components for the GPVI signaling cascade, including Syk, Btk, and phospholipase Cγ2. Interestingly, PrxII-mediated antioxidative protection of SHP-2 appeared to occur in the lipid rafts. PrxII-deficient platelets exhibited increased adhesion and aggregation upon collagen stimulation. Furthermore, in vivo experiments demonstrated that PrxII deficiency facilitated platelet-dependent thrombus formation in injured carotid arteries. This study reveals that PrxII functions as a protective antioxidant enzyme against collagen-stimulated platelet activation and platelet-dependent thrombosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
-
Brambilla, Marta; Rossetti, Laura; Zara, Chiara; Canzano, Paola; Giesen, Peter L A; Tremoli, Elena; Camera, Marina
2018-06-01
Tissue factor (TF), the key activator of the blood coagulation cascade and of thrombus formation, is also expressed by circulating human platelets. Despite the documented in-depth characterization of platelet TF carried out in the past 15 years, some authors still fail to identify TF in platelets, especially when assessment in platelet-rich plasma (PRP) or washed platelets is carried out. This study aims to extend the characterization of the subset of TF-positive platelets in PRP from healthy subjects and to verify how different centrifugation forces, used to prepare the PRP, could affect the analysis of TF-positive platelets. Data indicate that large-size platelets express significantly higher amount of TF compared to small-size cells, in terms of both TF protein and TF mRNA. Upon stimulation, large platelets readily expose on the cell membrane TF, which is functionally active, i.e., able to generate factor Xa (FXa) as well as thrombin. By contrast, TF activity in small platelets is almost completely quenched by tissue factor pathway inhibitor (TFPI), becoming indeed detectable only after treatment with an anti-TFPI antibody. Our data highlight that particular attention must be paid to the preparation and collection of the PRP since such preanalytical variables may influence the platelet recovery and in turn affect subsequent analysis, whether it is flow cytometry, functional activity tests, proteome, or transcriptome analysis. Indeed, the TF-positive subset of large platelets can easily be lost if centrifugation protocols are not optimized, thus erroneously leading to a false-negative result.
-
International Nuclear Information System (INIS)
Tsuda, Takatoshi; Kubota, Masahiro; Iwakubo, Akifumi
1989-01-01
Eighteen patients with postinfarction left ventricular aneurysm (LVA) were examined with indium-111-labeled autologous platelet scintigraphy to identify intracardiac thrombi and to investigate the effect of antithrombotic agents on thrombogenesitiy within the LVA. Indium-111-platelet scintigraphy had a sensitivity of 60% and a specificity of 100% in detecting LVA mural thrombi. Among 6 patients showing false-negative scintigraphic studies, 4 was managed on antiplatelet therapy. Of 9 patients showing active platelet deposition on initial study, including 8 not receiving antiplatelet therapy, 5 were treated with tichlopidine (300 mg/day) for 29.8±5.0 days. For the 5 patients, 2 had resolution and the 3 others had interruption of intraaneurysmal deposition in the second platelet study. For one patient receiving the third platelet study after warfarin therapy, it took two weeks to completely interrupt platelet deposition within the LVA. ECG gated radionuclide ventriculography and thallium-201 myocardial SPECT were also performed to assess left ventricular wall motion of left ventricular ejection fraction (LVEF) and myocardial blood perfusion. Thallium-201 SPECT showed apical or anteroapical perfusion defects. Radionuclide ventriculography pinpointed all 18 apical and anteroseptal aneurysms. A comparison between the thrombus positive group and the thrombus negative group revealed no statistical differences in LVEF and the period from the last myocardial infarction to the initial platelet scanning. These results suggest that indium-111 labeled platelet scintigraphy may be useful for identifying active left ventricular mural thrombi and for judging antiplatelet and anticoagulant therapy. (Namekawa, K)
-
Imaging experimental coronary artery thrombosis with indium-111 platelets
International Nuclear Information System (INIS)
Riba, A.L.; Thakur, M.L.; Gottschalk, A.; Zaret, B.L.
1979-01-01
The ability of cardiac scintigraphy with indium-111 ( 111 In)-labeled platelets to detect coronary artery thrombosis (CAT) was assessed in a canine model. Cardiac imaging and tissue distribution studies were performed shortly after administering 111 In-labeled platelets to 12 dogs (group 1) with acute CAT. Four dogs (group 2) with acute CAT were studied 2 and 22 hours after administering 111 In platelets. In addition, four dogs (group 3) with 24-hour-old CAT were similarly evaluated. In all group 1 animals, in vivo imaging 1 to 2 hours after 111 In platelet administration revealed intense uptake in the region of thrombus-containing left anterior descending arteries that was readily discernible from background blood pool activity. Sequential imaging of the four group 2 animals over a 22-hour period revealed no change in the scintigraphic pattern of the thrombosed arteries. In contrast, 111 In platelet imaging in the four group 3 animals with 24-hour-old CAT failed to reveal enhanced activity within the region of the thrombus-containing coronary artery. In the 12 group 1 animals, the CAT accumulated 69 +- 10 (mean +- SEM) times greater activity than present in blood and 651 +- 135 times greater activity than normal left ventricular myocardium. There was 24 +- 7 times greater 111 In activity in the damaged left anterior descending arteries compared with normal circumflex arteries. Similar uptake ratios were seen in group 2 animals. The 24-hour old thrombi from group 3 animals showed no enhanced 111 In uptake. This study demonstrates that experimental acute CAT can be detected readily with 111 In platelet cardiac scintigraphy
-
International Nuclear Information System (INIS)
Stratton, J.R.; Ritchie, J.L.; Hamilton, G.W.; Hammermeister, K.E.; Harker, L.A.
1981-01-01
Indium-111 platelet imaging, which can identify sites of active intravascular platelet deposition, and two dimensional echocardiography, which can identify intracardiac masses, can both be used to detect left ventricular thrombi noninvasively. We compared these techniques in 44 men at risk for thrombi from remote transmural myocardial infarction (31 patients) or cardiomyopathy (13 patients). All 44 patients underwent platelet imaging; 35 underwent echocardiography. On platelet imaging nine patients had thrombi and onehad a possible thrombus. Of these 10 studies, none were positive at 2 hours, 5 were positive at 24 hours and all were positive 48 or 72 hours after platelet labeling. Nine of these patients underwent echocardiography, and all had an intraventricular mass. The findings on platelet scanning were negative in six patients who had positive (four patients) or equivocally positive (two patients) findings on echocardiography. All patients with thrombi detected by either noninvasive method had transmural anterior myocardial infarction with ventricular aneurysm. Of the seven patients who underwent cardiac surgery or autopsy, three had thrombi. Platelet imaging failed to identify one thrombus in a patient in whom imaging was performed only at 24 hours after labeling. There were no false positive platelet images in this group. Five of these seven patients (two with throbi, three without) underwent echocardiography; in all cases the echocardiographic findings agreed with the pathologic findings. Both platelet imaging and echocardiography detect ventricular thrombi. Platelet imaging may detect only the most hematologically active thrombi. Both techniques may help define patients at risk of embolization and may be useful for in vivo assessment of antithrombotic drugs
-
Energy Technology Data Exchange (ETDEWEB)
Tsuda, Takatoshi; Kubota, Masahiro; Iwakubo, Akifumi and others
1989-03-01
Eighteen patients with postinfarction left ventricular aneurysm (LVA) were examined with indium-111-labeled autologous platelet scintigraphy to identify intracardiac thrombi and to investigate the effect of antithrombotic agents on thrombogenesitiy within the LVA. Indium-111-platelet scintigraphy had a sensitivity of 60% and a specificity of 100% in detecting LVA mural thrombi. Among 6 patients showing false-negative scintigraphic studies, 4 was managed on antiplatelet therapy. Of 9 patients showing active platelet deposition on initial study, including 8 not receiving antiplatelet therapy, 5 were treated with tichlopidine (300 mg/day) for 29.8+-5.0 days. For the 5 patients, 2 had resolution and the 3 others had interruption of intraaneurysmal deposition in the second platelet study. For one patient receiving the third platelet study after warfarin therapy, it took two weeks to completely interrupt platelet deposition within the LVA. ECG gated radionuclide ventriculography and thallium-201 myocardial SPECT were also performed to assess left ventricular wall motion of left ventricular ejection fraction (LVEF) and myocardial blood perfusion. Thallium-201 SPECT showed apical or anteroapical perfusion defects. Radionuclide ventriculography pinpointed all 18 apical and anteroseptal aneurysms. A comparison between the thrombus positive group and the thrombus negative group revealed no statistical differences in LVEF and the period from the last myocardial infarction to the initial platelet scanning. These results suggest that indium-111 labeled platelet scintigraphy may be useful for identifying active left ventricular mural thrombi and for judging antiplatelet and anticoagulant therapy. (Namekawa, K).
-
Comparison of platelet activation through hinge vs bulk flow in mechanical heart valves
Hedayat, Mohammadali; Borazjani, Iman
2017-11-01
Bileaflet mechanical heart valves increase the risk of thrombus formation in patients which is believed to be initiated by platelet activation. Platelets can be activated by the elevated shear stresses in the bulk flow during the systole phase or the flow through the hinge during the diastole. However, the importance of platelet activation by the bulk flow vs the hinge in MHVs has yet to be studied. Here, we investigate the contribution of each of the above mechanisms to the activation of platelets in MHs by performing simulation of the flow through a 25mm St. Jude Medical valve placed in a straight aorta. Two different gap sizes (250 and 150 micrometer) are used in this study. The simulations are done using a sharp interface curvilinear immersed boundary method along with a strong-coupling algorithm for FSI solver on overset grids. The platelet activation through the hinge for different gap sizes is compared to the activation in the bulk flow using two platelet activation models to ensure the consistency of the results. Our results for all gap sizes using different activation models show that the integration of platelet activation caused by the bulk flow is several times higher in comparison to the activation through the hinge. This work is supported by the American Heart Association Grant 13SDG17220022, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.
-
Deep venous thrombus characterization: ultrasonography, elastography and scattering operator
Directory of Open Access Journals (Sweden)
Thibaud Berthomier
2017-04-01
Full Text Available A thrombus or a blood clot is the result of blood coagulation which is a natural process to prevent bleeding. An inappropriate formation of a thrombus in a deep vein is known as Deep Venous Thrombosis (DVT. The main complication of a DVT is a Pulmonary Embolism (PE which occurs when a thrombus breaks loose and travels to the lungs. DVT, PE, or both are also known as Venous thromboembolism (VTE. It affects an estimated 300,000–600,000 Individuals just in the United States per year and can cause considerable morbidity and mortality. This multifactorial disease related to advanced age, immobility, surgery or obesity is an important public health issue. Our project is looking to link the VTE epidemiology (risk factors, patient history, PE to the thrombus structure. To reach our goals, we are collecting ultrasonography (echogenicity and elastography (stiffness of human thrombus. This manuscript describes our approach to create and preprocess a database using Toshiba Aplio 500. Our approaches to characterize the thrombus structure with ultrasound images are also described. The feature extraction is made with the scattering operator. Obtained features are then reduced using Principal Component Analysis and are analyzed to evaluate our approach.
-
Diagnosis of deep vein thrombosis using autologous indium-III-labelled platelets
International Nuclear Information System (INIS)
Fenech, A.; Hussey, J.K.; Smith, F.W.; Dendy, P.P.; Bennett, B.; Douglas, A.S.
1981-01-01
Forty-eight patients who had undergone surgical reduction of a fractured neck of femur or in whom deep vein thrombosis was suspected clinically were studied by ascending phlebography and imaging after injection of autologous indium-III-labelled platelets to assess the accuracy and value of the radioisotopic technique in diagnosing deep vein thrombosis. Imaging was performed with a wide-field gammacamera linked with data display facilities. Phlebography showed thrombi in 26 out of 54 limbs examined and a thrombus in the inferior vena cava of one patient; imaging the labelled platelets showed the thrombi in 24 of the 26 limbs and the thrombus in the inferior vena cava. The accumulation of indium-III at sites corresponding to those at which venous thrombi have been shown phlebographically indicates that this radioisotopic technique is a useful addition to methods already available for the detection of deep vein thrombosis. (author)
-
Diagnosis of deep vein thrombosis using autologous indium-III-labelled platelets
Energy Technology Data Exchange (ETDEWEB)
Fenech, A.; Hussey, J.K.; Smith, F.W.; Dendy, P.P.; Bennett, B.; Douglas, A.S. (Aberdeen Univ. (UK))
1981-03-28
Forty-eight patients who had undergone surgical reduction of a fractured neck of femur or in whom deep vein thrombosis was suspected clinically were studied by ascending phlebography and imaging after injection of autologous indium-III-labelled platelets to assess the accuracy and value of the radioisotopic technique in diagnosing deep vein thrombosis. Imaging was performed with a wide-field gamma camera linked with data display facilities. Phlebography showed thrombi in 26 out of 54 limbs examined and a thrombus in the inferior vena cava of one patient; imaging the labelled platelets showed the thrombi in 24 of the 26 limbs and the thrombus in the inferior vena cava. The accumulation of indium-III at sites corresponding to those at which venous thrombi have been shown phlebographically indicates that this radioisotopic technique is a useful addition to methods already available for the detection of deep vein thrombosis.
-
Factor H C-Terminal Domains Are Critical for Regulation of Platelet/Granulocyte Aggregate Formation
Directory of Open Access Journals (Sweden)
Adam Z. Blatt
2017-11-01
Full Text Available Platelet/granulocyte aggregates (PGAs increase thromboinflammation in the vasculature, and PGA formation is tightly controlled by the complement alternative pathway (AP negative regulator, Factor H (FH. Mutations in FH are associated with the prothrombotic disease atypical hemolytic uremic syndrome (aHUS, yet it is unknown whether increased PGA formation contributes to the thrombosis seen in patients with aHUS. Here, flow cytometry assays were used to evaluate the effects of aHUS-related mutations on FH regulation of PGA formation and characterize the mechanism. Utilizing recombinant fragments of FH spanning the entire length of the protein, we mapped the regions of FH most critical for limiting AP activity on the surface of isolated human platelets and neutrophils, as well as the regions most critical for regulating PGA formation in human whole blood stimulated with thrombin receptor-activating peptide (TRAP. FH domains 19–20 were the most critical for limiting AP activity on platelets, neutrophils, and at the platelet/granulocyte interface. The role of FH in PGA formation was attributed to its ability to regulate AP-mediated C5a generation. AHUS-related mutations in domains 19–20 caused differential effects on control of PGA formation and AP activity on platelets and neutrophils. Our data indicate FH C-terminal domains are key for regulating PGA formation, thus increased FH protection may have a beneficial impact on diseases characterized by increased PGA formation, such as cardiovascular disease. Additionally, aHUS-related mutations in domains 19–20 have varying effects on control of TRAP-mediated PGA formation, suggesting that some, but not all, aHUS-related mutations may cause increased PGA formation that contributes to excessive thrombosis in patients with aHUS.
-
Delayed-onset of procoagulant signalling revealed by kinetic analysis of COAT platelet formation.
Alberio, Lorenzo; Ravanat, Catherine; Hechler, Béatrice; Mangin, Pierre H; Lanza, François; Gachet, Christian
2017-06-02
The combined action of collagen and thrombin induces the formation of COAT platelets, which are characterised by a coat of procoagulant and adhesive molecules on their surface. Although recent work has started to highlight their clinical relevance, the exact mechanisms regulating the formation of procoagulant COAT platelets remain unclear. Therefore, we employed flow cytometry in order to visualise in real time surface and intracellular events following simultaneous platelet activation with convulxin and thrombin. After a rapid initial response pattern characterised by the homogenous activation of the fibrinogen receptor glycoprotein IIb/IIIa in all platelets, starting with a delay of about 2 minutes an increasing fraction transforms to procoagulant COAT platelets. Their surface is characterised by progressive loss of PAC-1 binding, expression of negative phospholipids and retention of α-granule von Willebrand factor. Intracellular events in procoagulant COAT platelets are a marked increase of free calcium into the low micromolar range, concomitantly with early depolarisation of the mitochondrial membrane and activation of caspase-3, while non-COAT platelets keep the intracellular free calcium in the nanomolar range and maintain an intact mitochondrial membrane. We show for the first time that the flow-cytometrically distinct fractions of COAT and non-COAT platelets differentially phosphorylate two signalling proteins, PKCα and p38MAPK, which may be involved in the regulation of the different calcium fluxes observed in COAT versus non-COAT platelets. This study demonstrates the utility of concomitant cellular and signalling evaluation using flow cytometry in order to further dissect the mechanisms underlying the dichotomous platelet response observed after collagen/thrombin stimulation.
-
Lee, Wonhwa; Kim, Mi-Ae; Park, InWha; Hwang, Jae Sam; Na, MinKyun; Bae, Jong-Sup
2017-11-01
Tenebrio molitor is an edible insect that has antimicrobial, anticancer, and antihypertensive effects. The aim of this study was to identify the unreported bioactive compounds from T. molitor larvae with inhibitory activities against factor Xa (FXa) and platelet aggregation. Isolated compounds were evaluated for their anti-FXa and anti-platelet aggregation properties by monitoring clotting time, platelet aggregation, FXa activity, and thrombus formation. A diketopiperazine (1, cyclo( L -Pro- L -Tyr)) and a phenylethanoid (2, N-acetyltyramine) were isolated and inhibited the catalytic activity of FXa in a mixed inhibition model and inhibited platelet aggregation induced by adenosine diphosphate (ADP) and U46619. They inhibited ADP- and U46619-induced phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS) and the expression of P-selectin and PAC-1 in platelets. They also improved the production of nitric oxide and inhibited the oversecretion of endothelin-1 compared to that of the ADP- or U46619-treated group. In an animal model of arterial and pulmonary thrombosis, the isolated compounds showed enhanced antithrombotic effects. They also elicited anticoagulant effects in mice. Compounds 1-2 inhibited ADP-, collagen-, or U46619-induced platelet aggregation and showed similar anti-thrombotic efficacy to rivaroxaban, a positive control. Therefore, 1-2 could serve as candidates and provide scaffolds for the development of new anti-FXa and anti-platelet drugs. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
International Nuclear Information System (INIS)
Amer, M.M.
2010-01-01
Several studies have demonstrated that enhanced platelets reactivity associated with hyperlipidaemia plays a role in the formation of atherosclerosis. Thus, platelet count, platelet aggregation in response to the agonists ADP, collagen and thromboxan B2 (TxB 2 ) were investigated in the normal and hyperlipidaemic rats to elucidate the role of some antioxidants, as modulating factors in the development of atherosclerosis. Serum concentrations of the major lipid classes, thyroid hormones, serum glutathione as well as platelet count and aggregation were determined in normal lipidemic rats (control) and compared with their corresponding levels in hyperlipidaemic ones. Hyperlipidaemia was induced by feeding rats with diet enriched with 20 g cow milk butter/100 g diet for 8 weeks. Garlic oil (200 mg/kg b.w.) and/or taurine (500 ml/kg b.w.) were peritoneal injected from the beginning of the 9th week for 15 consecutive days. Incorporation of extra fat in diet of rats for long term led to a significant (p 2 levels. On the other hand, HDL-cholesterol, serum glutathione (GSH), and T 3 and T 4 hormones level were significantly (p 2 level also showed a significant decrease. Conversely, serum HDL, T 3 , T 4 and GSH levels were significantly increased. These results denote that garlic oil and/or taurine may decrease the risk of atherosclerosis and thrombus formation associated with hyperlipidaemia through modulating the quantity and quality of platelets in male rats
-
Preoperative and postoperative evaluation of vascular diseases by 111In-oxine platelet scintigraphy
International Nuclear Information System (INIS)
Nishibe, Toshiya; Hiraoka, Tomoya; Sakuma, Makoto; Sakai, Keisuke; Yasuda, Keishu; Tanabe, Tatsuzo; Nagao, Kazuhiko; Ito, Kazuo
1991-01-01
111 In-oxine platelet scintigraphy was performed on 20 patients with various vascular diseases to assess its clinical usefulness as a diagnostic procedure. Especially we evaluated its usefulness for thrombus formation after Ivaron sponge occlusion method (ISO method) and endotheliazation of prosthetic grafts. Negative image in thoracic false lumen was obtained 2 or 3 weeks after operation in all patients whose dissection was completely repaired by ISO method. It suggested early thromboexclusion in thoracic false lumen in which Ivalon sponge was implanted. Negative image was observed in two cases of saphenous vein graft and one of Dacron graft. The case of Dacron graft was examined 415 days after implantation. Negative result in this case would be accounted for by stabilized fibrin layer or good endothelial coverrage. The results suggest that 111 In-oxine platelet scintigraphy is an appropriate technique for evaluating the encapsulation of prosthetic grafts and thromboexclusion after ISO method. (author)
-
Successful catheter directed thrombolysis of IVC and renal vein occlusive thrombus.
LENUS (Irish Health Repository)
McCarthy, E
2011-11-01
Thrombus formation is a recognised complication of IVC filter placement, however IVC and bilateral renal vein occlusion secondary to thrombus is much less common. We present a case of infrahepatic caval and bilateral renal vein occlusion secondary to thrombosis of a suprarenal IVC filter. With progressive clinical deterioration and failure of conservative medical management the patient underwent successful mechanical disruption and catheter directed thrombolysis.
-
Directory of Open Access Journals (Sweden)
Ono Koji
2012-12-01
Full Text Available Abstract Background The aim of this study was to define the independent determinants of left atrial appendage (LAA thrombus among various echocardiographic parameters measured by Velocity Vector Imaging (VVI in patients with nonvalvular atrial fibrillation (AF receiving warfarin, particularly in patients with a low CHADS2 score. Methods LAA emptying fraction (EF and LAA peak longitudinal strain were measured by VVI using transesophageal echocardiography in 260 consecutive patients with nonvalvular persistent AF receiving warfarin. The patients were divided into two groups according to the presence (n=43 or absence (n=217 of LAA thrombus. Moreover, the patients within each group were further divided into subgroups according to a CHADS2 score ≤1. Results Multivariate logistic regression analysis showed that LAAEF was an independent determinant of LAA thrombus in the subgroup of 140 with a low CHADS2 score. Receiver operating characteristics curve analysis showed that an LAAEF of 21% was the optimal cutoff value for predicting LAA thrombus. Conclusions LAA thrombus formation depended on LAA contractility. AF patients with reduced LAA contractile fraction (LAAEF ≤21% require strong anticoagulant therapy to avoid thromboembolic events regardless of a low CHADS2 score (≤1.
-
Directory of Open Access Journals (Sweden)
Taisuke Watanabe
2017-01-01
Full Text Available Platelet concentrates should be quality-assured of purity and identity prior to clinical use. Unlike for the liquid form of platelet-rich plasma, platelet counts cannot be directly determined in solid fibrin clots and are instead calculated by subtracting the counts in other liquid or semi-clotted fractions from those in whole blood samples. Having long suspected the validity of this method, we herein examined the possible loss of platelets in the preparation process. Blood samples collected from healthy male donors were immediately centrifuged for advanced platelet-rich fibrin (A-PRF and concentrated growth factors (CGF according to recommended centrifugal protocols. Blood cells in liquid and semi-clotted fractions were directly counted. Platelets aggregated on clot surfaces were observed by scanning electron microscopy. A higher centrifugal force increased the numbers of platelets and platelet aggregates in the liquid red blood cell fraction and the semi-clotted red thrombus in the presence and absence of the anticoagulant, respectively. Nevertheless, the calculated platelet counts in A-PRF/CGF preparations were much higher than expected, rendering the currently accepted subtraction method inaccurate for determining platelet counts in fibrin clots. To ensure the quality of solid types of platelet concentrates chairside in a timely manner, a simple and accurate platelet-counting method should be developed immediately.
-
International Nuclear Information System (INIS)
Iqbal, M.W.; Fayyaz, A.
2014-01-01
Left ventricular thrombus (LVT) formation is a well known complication seen in patients presenting with acute anterior wall ST-segment elevation myocardial infarction (STEMI). In previous studies the incidence of this complication, after acute myocardial infarction (AMI) has been reported to be 4% to 60% in large anterior wall STEMI, depending significantly upon the method as well as time of reperfusion therapy after STEMI. Objective: The objective of this descriptive case series study was to evaluate the frequency of left ventricular thrombus formation in patients after acute anterior wall ST-Segment elevation myocardial infarction. Methodology: In this study, 100 patients with anterior wall STEMI presenting to cardiac emergency or coronary care unit (CCU) of Cardiac complex, Gulab Devi Hospital, were selected on non-probability, purposive sampling meeting inclusion criteria, after taking written informed consent. All the patients were treated initially for management of acute STEMI, including use of thrombolytics where indicated. 2-D Transthoracic echocardiography (TTE) was performed during the same admission to assess presence of LV thrombus (LVT). Results: The mean age of the patients was 54.3 +- 11.4 years. There were 84(84%) male patients and 16 (16%) female patients. LVT was present in 28 (28%) patients on TTE. Among those, there were 23 (82.1%) male and 5 (17.9%) female patients. However, out of 84 male patients 27.4% develop LVT and among 16 female patients this ratio was 31.3%. The LV thrombus was independent of age and gender. LV thrombus was significantly less in thrombolytic group as compared to those who were not given this therapy, i.e. p value <0.05. Conclusion: Patients with anterior wall acute STEMI not infrequently develop the complication of development of LV thrombus. In this study the frequency of LV thrombus formation after anterior wall acute STEMI was 28%. (author)
-
In-111 platelets used in evaluation of emboli and thrombi in patients with cerebrovascular accident
International Nuclear Information System (INIS)
Kuecuek, N.O.; Aras, G.; Ibis, E.; Soylu, A.; Tascilar, N.; Yuecemen, N.; Mutluer, N.
2000-01-01
Studies with In-111 platelets were conducted to evaluate pulmonary embolus, deep vein thrombus and cardiac thrombus. This study aimed to evaluate active thrombi and possible new emboli in patients with cerebrovascular accident (CVA) in the first 24 hours by using autologous In-111 platelets. Twenty-five patients were included in the study. Carotid artery thrombi observed in 10 patients with this technique were confirmed by Doppler ultrasonography. Intracranial thrombi appearing in 3 cases were verified by X-ray computed tomography (CT). Scintigraphy of 8 patients who showed findings suggesting CVA in CT revealed no abnormal accumulation. This was attributed to the possibility that they were small in size, deep in location and/or were also quite aged. Abnormal accumulations observed in the lungs of 3 patients and in the mediastinum and pelvis in one patient were verified by other radiological methods. In-111 platelet study was found to be useful in patients with CVA to evaluate the active thrombi and possible emboli in the early period before clinical symptoms appeared. (author)
-
Scintigraphic detection of thrombi using indium-111-labeled autologous platelets
International Nuclear Information System (INIS)
Ikeoka, Kiyomitsu; Todo, Yasuhiro; Konishiike, Atsushi; Fujisue, Ryu; Ohyanagi, Mitsumasa; Yasutomi, Nagao; Tanimoto, Masaho; Kawai, Yoshitaka; Iwasaki, Tadaaki
1985-01-01
Intracardiac and arterial thrombi were examined by scintigraphy using In-111-oxine labeled autologous platelets. 1. In 22 cases of myocardial infarction including six with ventricular aneurysms, four had positive findings of thrombi on imaging and detected also by echocardiography. All four had ventricular aneurysms. The so-called ''moya-moya'' echoes (fuzzy echoes) were demonstrated in two of these four cases. 2. We encountered two cases with positive findings on imaging in 13 with mitral valve disease. These two had systemic embolic episodes after scintigraphic examination. ''Moya-moya'' echoes were detected in the left atrial cavity in four with negative findings on imaging. 3. Positive images were obtained in two of three with acute arterial occlusive disease, and in both cases platelet deposition was observed in the proximal site of obstruction. Though thrombectomy was performed for one of these two cases, no thrombus was detected at the site of platelet deposition. After one month, re-examination revealed only negative findings in all sites in both these patients. 4. In the six cases of aortic aneurysm, three had platelet deposition within their aneurysms, and surgery was performed for these positive cases, but one of them had no thrombus. 5. Positive images were obtained in only one of seven patients with chronic arterial occlusive disease. 6. Coagulation tests and platelet studies were investigated for patients with positive or negative platelet scans. Only the data of the thrombo-test showed a significant difference (97 +- 9 % vs 23 +- 7 %, p < 0.001). Three cases of positive imaging became negative after anticoagulant therapy. 7. We tried ECT for eight cases 24 hours after injection of In-111-oxine labeled platelets. Three cases showed clear images of thrombi, while the planar images could not detect them at an early stage. Therefore, we propose that ECT can be a useful technique for diagnosing intracardiac thrombi in early stage. (author)
-
Jackson, Joseph W; Singh, Meera V; Singh, Vir B; Jones, Letitia D; Davidson, Gregory A; Ture, Sara; Morrell, Craig N; Schifitto, Giovanni; Maggirwar, Sanjay B
2016-01-01
Platelets play an essential role in hemostasis and wound healing by facilitating thrombus formation at sites of injury. Platelets also mediate inflammation and contain several pro-inflammatory molecules including cytokines and chemokines that mediate leukocyte recruitment and activation. Not surprisingly, platelet dysfunction is known to contribute to several inflammatory disorders. Antiplatelet therapies, such as aspirin, adenosine diphosphate (ADP) antagonists, glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors, and anticoagulants such as warfarin, dampen platelet activity at the risk of unwarranted bleeding. Thus, the development of drugs that reduce platelet-mediated inflammation without interfering with thrombus formation is of importance to combat platelet-associated disorders. We have shown here for the first time that the tetracycline antibiotic, minocycline, administered to HIV-infected individuals reduces plasma levels of soluble CD40L and platelet factor 4 levels, host molecules predominately released by platelets. Minocycline reduced the activation of isolated platelets in the presence of the potent platelet activator, thrombin, as measured by ELISA and flow cytometry. Platelet degranulation was reduced upon exposure to minocycline as shown by mepacrine retention and flow cytometry. However, minocycline had no effect on spreading, aggregation, GPIIb/IIIa activation, or in vivo thrombus formation. Lastly, immunoblot analysis suggests that the antiplatelet activity of minocycline is likely mediated by inhibition of mixed lineage kinase 3 (MLK3)-p38 MAPK signaling axis and loss of p38 activity. Our findings provide a better understanding of platelet biology and a novel repurposing of an established antibiotic, minocycline, to specifically reduce platelet granule release without affecting thrombosis, which may yield insights in generating novel, specific antiplatelet therapies.
-
Evaluation of radiocolloids as thrombus imaging agents. Effect of particle size on thrombus uptake
Energy Technology Data Exchange (ETDEWEB)
Rosenthal, S.N.; Bardfeld, P.A.
1985-01-01
Thrombus uptake values of several /sup 99m/Tc labeled radiocolloids determined using an experimental rodent model of deep venous thrombosis were correlated with particle size distributions. The thrombus uptake values increased with increasing mean particle size. The /sup 99m/Tc-tin colloid had the highest thrombus uptake value of any of the colloids used in this study.
-
Lukito, P; Wong, A; Jing, J; Arthur, J F; Marasco, S F; Murphy, D A; Bergin, P J; Shaw, J A; Collecutt, M; Andrews, R K; Gardiner, E E; Davis, A K
2016-11-01
Essentials Relationship of acquired von Willebrand disease (VWD) and platelet dysfunction is explored. Patients with ventricular assist devices and on extracorporeal membrane oxygenation are investigated. Acquired VWD and platelet receptor shedding is demonstrated in the majority of patients. Loss of platelet adhesion receptors glycoprotein (GP) Ibα and GPVI may increase bleeding risk. Background Ventricular assist devices (VADs) and extracorporeal membrane oxygenation (ECMO) are associated with bleeding that is not fully explained by anticoagulant or antiplatelet use. Exposure of platelets to elevated shear in vitro leads to increased shedding. Objectives To investigate whether loss of platelet receptors occurs in vivo, and the relationship with acquired von Willebrand syndrome (AVWS). Methods Platelet counts, coagulation tests and von Willebrand factor (VWF) analyses were performed on samples from 21 continuous flow VAD (CF-VAD), 20 ECMO, 12 heart failure and seven aortic stenosis patients. Levels of platelet receptors were measured by flow cytometry or ELISA. Results The loss of high molecular weight VWF multimers was observed in 18 of 19 CF-VAD and 14 of 20 ECMO patients, consistent with AVWS. Platelet receptor shedding was demonstrated by elevated soluble glycoprotein (GP) VI levels in plasma and significantly reduced surface GPIbα and GPVI levels in CF-VAD and ECMO patients as compared with healthy donors. Platelet receptor levels were also significantly reduced in heart failure patients. Conclusions These data link AVWS and increased platelet receptor shedding in patients with CF-VADs or ECMO for the first time. Loss of the platelet surface receptors GPIbα and GPVI in heart failure, CF-VAD and ECMO patients may contribute to ablated platelet adhesion/activation, and limit thrombus formation under high/pathologic shear conditions. © 2016 International Society on Thrombosis and Haemostasis.
-
Modulation of platelet functions by crude rice (Oryza sativa) bran policosanol extract.
Wong, Wai-Teng; Ismail, Maznah; Imam, Mustapha Umar; Zhang, Yi-Da
2016-07-28
Rice bran is bioactive-rich and has proven health benefits for humans. Moreover, its source, the brown rice has antioxidant, hypolipidemic and other functional properties that are increasingly making it a nutritional staple especially in Asian countries. This study investigated the antiplatelet aggregation mechanisms of crude hexane/methanolic rice bran extract, in which policosanol was the targeted bioactive. Platelets play a vital role in pathogenesis of atherosclerosis and cardiovascular diseases, and their increased activities could potentially cause arterial thrombus formation or severe bleeding disorders. Thus, in this study, platelet aggregation and adhesion of platelets to major components of basal lamina were examined in vitro. In addition, cellular protein secretion was quantified as a measurement of platelet activation. Adenosine diphosphate (ADP), collagen, and arachidonic acid (AA)-induced aggregation were studied using the microtiter technique. Rat platelets were pre-treated with various concentrations of policosanol extract, and the adhesion of platelets onto collagen- and laminin-coated surface (extracellular matrix) was studied using the acid phosphatase assay. The effect of crude policosanol extract on released proteins from activated platelets was measured using modified Lowry determination method. Rice bran policosanol extract significantly inhibited in vitro platelet aggregation induced by different agonists in a dose dependent manner. The IC50 of ADP-, collagen-, and AA-induced platelet aggregation were 533.37 ± 112.16, 635.94 ± 78.45 and 693.86 ± 70.57 μg/mL, respectively. The present study showed that crude rice bran policosanol extract significantly inhibited platelet adhesion to collagen in a dose dependent manner. Conversely, at a low concentration of 15.625 μg/mL, the extract significantly inhibited platelet adhesion to laminin stimulated by different platelet agonists. In addition to the alteration of cell adhesive
-
International Nuclear Information System (INIS)
Nygaard, Gyrid; Herfindal, Lars; Kopperud, Reidun; Aragay, Anna M.; Holmsen, Holm; Døskeland, Stein Ove; Kleppe, Rune; Selheim, Frode
2014-01-01
Highlights: • We investigated the impact of cyclic nucleotide analogues on platelet activation. • Different time dependence were found for inhibition of platelet activation. • Additive effect was found using PKA- and PKG-activating analogues. • Our results may explain some of the discrepancies reported for cNMP signalling. - Abstract: In platelets, nitric oxide (NO) activates cGMP/PKG signalling, whereas prostaglandins and adenosine signal through cAMP/PKA. Cyclic nucleotide signalling has been considered to play an inhibitory role in platelets. However, an early stimulatory effect of NO and cGMP-PKG signalling in low dose agonist-induced platelet activation have recently been suggested. Here, we investigated whether different experimental conditions could explain some of the discrepancy reported for platelet cGMP-PKG-signalling. We treated gel-filtered human platelets with cGMP and cAMP analogues, and used flow cytometric assays to detect low dose thrombin-induced formation of small platelet aggregates, single platelet disappearance (SPD), platelet-derived microparticles (PMP) and thrombin receptor agonist peptide (TRAP)-induced P-selectin expression. All four agonist-induced platelet activation phases were blocked when platelets were costimulated with the PKG activators 8-Br-PET-cGMP or 8-pCPT-cGMP and low-doses of thrombin or TRAP. However, extended incubation with 8-Br-PET-cGMP decreased its inhibition of TRAP-induced P-selectin expression in a time-dependent manner. This effect did not involve desensitisation of PKG or PKA activity, measured as site-specific VASP phosphorylation. Moreover, PKG activators in combination with the PKA activator Sp-5,6-DCL-cBIMPS revealed additive inhibitory effect on TRAP-induced P-selectin expression. Taken together, we found no evidence for a stimulatory role of cGMP/PKG in platelets activation and conclude rather that cGMP/PKG signalling has an important inhibitory function in human platelet activation
-
International Nuclear Information System (INIS)
Asmis, Lars; Tanner, Felix C.; Sudano, Isabella; Luescher, Thomas F.; Camici, Giovanni G.
2010-01-01
Background: DMSO is routinely infused together with hematopoietic cells in patients undergoing myeloablative therapy and was recently found to inhibit smooth muscle cells proliferation and arterial thrombus formation in the mouse by preventing tissue factor (TF), a key activator of the coagulation cascade. This study was designed to investigate whether DMSO prevents platelet activation and thus, whether it may represent an interesting agent to be used on drug eluting stents. Methods and results: Human venous blood from healthy volunteers was collected in citrated tubes and platelet activation was studied by cone and platelet analyzer (CPA) and rapid-platelet-function-assay (RPFA). CPA analysis showed that DMSO-treated platelets exhibit a lower adherence in response to shear stress (-15.54 ± 0.9427%, n = 5, P < 0.0001 versus control). Additionally, aggregometry studies revealed that DMSO-treated, arachidonate-stimulated platelets had an increased lag phase (18.0% ± 4.031, n = 9, P = 0.0004 versus control) as well as a decreased maximal aggregation (-6.388 ± 2.212%, n = 6, P = 0.0162 versus control). Inhibitory action of DMSO could be rescued by exogenous thromboxane A2 and was mediated, at least in part, by COX-1 inhibition. Conclusions: Clinically relevant concentrations of DMSO impair platelet activation by a thromboxane A2-dependent, COX-1-mediated effect. This finding may be crucial for the previously reported anti-thrombotic property displayed by DMSO. Our findings support a role for DMSO as a novel drug to prevent not only proliferation, but also thrombotic complications of drug eluting stents.
-
Directory of Open Access Journals (Sweden)
Ahmed Fathy
2011-09-01
Conclusion: From our study, we can conclude that TDE can be used for estimation of systolic and diastolic functions of LV and hence identification of patients at high risk for LV thrombus formation after first time acute anterior myocardial infarction and we recommend more studies to support our results about the importance of the role of oral anticoagulant after AMI.
-
Mural Thrombus in the Normal-Appearing Descending Thoracic Aorta of a Chronic Smoker
Habib, Habib; Hsu, Judy; Winchell, Patricia Jo; Daoko, Joseph
2013-01-01
Thrombus formation in an atherosclerotic or aneurysmal descending thoracic aorta is a well-described, frequently encountered vascular condition. In comparison, thrombus formation in a normal-appearing descending thoracic aorta is reported far less often. We describe the case of a 46-year-old woman who had splenic and renal infarctions secondary to embolic showers from a large, mobile thrombus in a morphologically normal proximal descending thoracic aorta. After the patient underwent anticoagulation, stent-grafting, and surgical bypass to correct an arterial blockage caused by the stent-graft, she resumed a relatively normal life. In contrast with other cases of a thrombotic but normal-appearing descending thoracic aorta, this patient had no known malignancy or systemic coagulative disorders; her sole risk factor was chronic smoking. We discuss our patient's case and review the relevant medical literature, focusing on the effect of smoking on coagulation physiology. PMID:24391341
-
Thrombus aspiration catheter is a Dottering balloon
Directory of Open Access Journals (Sweden)
D. Sheshagiri Rao
2016-07-01
Full Text Available Coronary angiogram in a young man with history of STEMI with delayed presentation revealed subtotal occlusion of left anterior descending artery (LAD with large thrombotic filling defect distal to the critical lesion. PCI was preferred without delay because of ongoing chest pain. Several runs of thrombus aspiration failed to detect any visible thrombus. However, the immediate angiogram after thrombus aspiration showed complete distal embolization of the thrombus which could have been achieved by Dottering or balloon dilatation. In contrary to the general perception, does thrombus aspiration push more thrombus than it can aspirate?
-
Kuno, Toshiki; Imaeda, Syohei; Hashimoto, Kenji; Ryuzaki, Toshinobu; Saito, Tetsuya; Yamazaki, Hiroyuki; Tabei, Ryota; Kodaira, Masaki; Hase, Manabu; Numasawa, Yohei
2018-03-01
We report the case of a 71-year-old woman diagnosed with recent inferior myocardial infarction complicated with right ventricular infarction and a right ventricular thrombus. Three-dimensional transthoracic echocardiography, contrast-enhanced computed tomography, and cardiac magnetic resonance imaging clearly detected a thrombus. We consider cases with a recent right ventricular infarction to require assessment for thrombus formations in the right ventricle. Fortunately, vigorous anticoagulation therapy resolved the thrombi in both the right ventricle and right coronary artery.
-
Selheim, F; Fukami, M H; Holmsen, H; Vassbotn, F S
2000-09-01
Human platelets release platelet-derived growth factor (PDGF) from alpha-granules during platelet activation. We have previously shown that platelets have PDGF alpha-receptors, a transmembrane tyrosine kinase that takes part in negative feedback regulation during platelet activation. Here we have described a study of PDGF-induced tyrosine phosphorylation of platelet substrates and phosphoinositide 3-kinase (PI-3K) activity in collagen-stimulated platelets. By immunoblotting with phosphotyrosine antibodies of collagen-activated platelets we found that PDGF increased the phosphorylation of several platelet substrates, e.g. pp140, pp120 and pp85. PDGF inhibited collagen-induced platelet activation in the presence of inhibitors of autocrine stimulation, thus blocking the pure collagen-induced signal transduction. PDGF enhanced the collagen-induced formation of PtdIns(3,4)P(2) and PtdIns(3,4,5)P(3) as measured by HPLC. Wortmannin and LY294002, two unrelated inhibitors of PI-3K, were used to investigate the role of PI-3K in PDGF-induced platelet signalling. Incubation of platelets with wortmannin and LY294002 blocked the formation of three phosphorylated inositides as well as the inhibitory effect of PDGF on collagen-induced platelet activation. We conclude that the inhibitory effect of PDGF on platelet activation is PI-3K dependent. This is the first demonstration of a negative regulatory function of 3-phosphorylated inositides in platelets.
-
Okuyama, Hidenobu; Hirono, Osamu; Liu, Ling; Takeishi, Yasuchika; Kayama, Takamasa; Kubota, Isao
2006-08-01
It is sometimes difficult to make a diagnosis of cardioembolic stroke in the stroke care unit, because of the splashing and vanishing of the intracardiac source of the emboli on transesophageal echocardiography. Serum fibrin-monomer (FM) is a new marker for coagulation activity that is useful for identifying older individuals at increased risk of ischemic stroke. Two hundred and four patients with acute ischemic stroke were examined for serum coagulation and fibrinolytic activity on admission, and underwent transesophageal echocardiography within 7 days of onset. Serum levels of FM was significantly higher in patients with left atrial appendage (LAA) thrombus formation (n=24) than in those with no thrombus (88+/-52 vs 14+/-9 microg/ml, pvs 8+/-5 microg/ml, pstroke.
-
Thrombus aspiration catheter is a Dottering balloon.
Sheshagiri Rao, D; Barik, Ramachandra; Prasad, Akula Siva
2016-01-01
Coronary angiogram in a young man with history of STEMI with delayed presentation revealed subtotal occlusion of left anterior descending artery (LAD) with large thrombotic filling defect distal to the critical lesion. PCI was preferred without delay because of ongoing chest pain. Several runs of thrombus aspiration failed to detect any visible thrombus. However, the immediate angiogram after thrombus aspiration showed complete distal embolization of the thrombus which could have been achieved by Dottering or balloon dilatation. In contrary to the general perception, does thrombus aspiration push more thrombus than it can aspirate? Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.
-
Hernandez, Maria Rosa; Alvarez-Guerra, Miriam; Escolar, Ginés; Chiavaroli, Carlo; Hannaert, Patrick; Garay, Ricardo P
2004-08-01
The hemostatic agent ethamsylate enhances membrane expression of P-selectin in human platelets, but whether this promotes platelet-leukocyte aggregate formation is unknown. Here we investigated this point by flow cytometry determination of human platelet-leukocyte aggregates under basal conditions and after whole-blood perfusion through a damaged rabbit aorta segment. Actions of ethamsylate on adhesive molecules of platelets and leukocytes were investigated in parallel. Under basal conditions, ethamsylate was unable to modify whole-blood platelet-leukocyte aggregation, but following whole-blood perfusion through a damaged vessel, ethamsylate produced a modest, but significant increase in platelet-leukocyte aggregates (48+/-21 and 45+/-26% above control levels at ethamsylate 20 and 40 microm respectively). In isolated leukocyte plasma membranes, 14C-ethamsylate specifically bound up to an amount of 660 pmol/mg protein. Moreover, at concentrations > or =1 microm, ethamsylate induced an important (100-200%) and significant increase in the P-selectin glycoprotein ligand 1 (PSGL-1) fluorescence signal in isolated leukocytes and was unable to significantly modify the percentage of CD11b-positive cells. However, no significant changes in aggregate formation were found when ethamsylate was incubated with isolated leukocytes and blood was reconstituted and perfused. In isolated platelet cell membranes, anti-P-selectin antibody and the anti-integrin RGD-containing pentapeptide (GRDGS) were unable to displace 14C-ethamsylate binding. In conclusion, ethamsylate specifically binds to plasma membranes of leukocytes, enhances membrane PSGL-1 expression and promotes leukocyte-platelet aggregation in whole-blood perfused through a damaged vascular segment. These results together with the previously observed enhancement of platelet P-selectin membrane expression [Thromb. Res. (2002)107:329-335] confirms and extends the view that ethamsylate acts on the first step of hemostasis, by
-
Detection of intracardiac thrombi by 111In-oxine platelet imaging
International Nuclear Information System (INIS)
Nishimura, Tsunehiko; Hayashi, Makoto; Hayashida, Kohei; Uehara, Toshiisa; Naito, Hiroaki; Kozuka, Takahiro; Boku, Eidai; Sakakibara, Hiroshi
1985-01-01
111 In-oxine platelet imaging (RI) was undertaken in 55 patients with suspected intracardiac thrombi. The results were compared with those from echocardiography (US) and computed tomography (CT). Sensitivity and specificity of RI were 71 % and 92 %, respectively. Visualizing thrombi on RI was seen in 10 (56 %) of 18 patients receiving anticoagulant therapy such as Warfarin (Group A) and in 12 (92 %) of 13 patients without it (Group B). This implied that active platelet deposition is inhibited by giving Warfarin. Regarding the size of thrombi, three methods showed the same size in 11 (85 %) of Group B. RI showed smaller thrombi than US and CT in 7 (39 %) of Group A, and failed to reveal them in 8 (44 %). Unlike morphological diagnosis by US and CT, RI proved to be of value in the evaluation of the activity of platelets (platelet deposition on the surface of thrombus). This method can also be used in the evaluation of thrombogenity. (Namekawa, K.)
-
Selective inhibition by a synthetic hirudin peptide of fibrin-dependent thrombosis in baboons
International Nuclear Information System (INIS)
Cadroy, Y.; Hanson, S.R.; Harker, L.A.; Maraganore, J.M.
1991-01-01
To determine the importance of the thrombin substrate recognition exosite for fibrinogen binding in the formation of both arterial and venous thrombi the authors evaluated the antithrombotic effects of the tyrosine-sulfated dodecapeptide from residues 53-64 of hirudin (H peptide) in a nonhuman primate model. This peptide was studied because it inhibits thrombin cleavages of fibrinogen by simple competition without blocking enzyme catalytic-site function. When an exteriorized arteriovenous access shunt model was used in baboons (Papio anubis), thrombus formation was induced by placing a thrombogenic device made of (i) a segment of tubing coated covalently with type I collagen, which generated platelet-rich thrombi under arterial flow conditions, and (ii) two subsequent annular regions of flow expansion that produced fibrin-rich thrombi typically associated with venous valves and veins. Thrombus formation was quantified by measurements of 111 In-labeled platelet and 125 I-labeled fibrinogen deposition in both arterial-flow and venous-flow portions of the device. These finding suggest that, by competitive inhibition of fibrinogen binding to thrombin, fibrin-rich venous-type thrombus formation may be selectively prevented. This strategy may be therapeutically attractive for preserving normal platelet function when conventional anticoagulant therapy is contraindicated
-
Arad, Ariela; Proulle, Valerie; Furie, Richard A.; Furie, Barbara C.
2011-01-01
Antiphospholipid syndrome is characterized by thrombosis, recurrent fetal loss, and the presence of the lupus anticoagulant, anticardiolipin antibodies, or anti–β2-glycoprotein-1 (anti–β2-GP1) antibodies. Although anti–β2-GP1 antibodies have been documented as a biomarker for diagnosis of antiphospholipid syndrome, their direct role in the pathogenesis of thrombosis is unknown. We have demonstrated using intravital microscopy that anti–β2-GP1 autoantibodies purified from the sera of patients with antiphospholipid syndrome complicated by thrombosis greatly amplify thrombus size after laser-induced vessel wall injury in live mice. Anti–β2-GP1 autoantibodies from 3 patients with antiphospholipid syndrome were affinity-purified using human β2-GP1 bound to agarose. The effects of purified anti–β2-GP1 IgG autoantibodies, of anti–β2-GP1–depleted IgG, and of IgG from normal human sera on thrombus formation were measured in mice after arterial injury in the cremaster muscle. Before injury, purified anti–β2-GP1 IgG autoantibodies, anti–β2-GP1 antibody–depleted IgG, or IgG from normal human sera were infused. Increasing amounts of purified anti–β2-GP1 autoantibodies increased thrombus size in a dose-dependent manner, whereas neither anti–β2-GP1 antibody-depleted IgG nor IgG from normal serum affected thrombus size. These results indicate that anti–β2-GP1 IgG autoantibodies in antiphospholipid syndrome patient sera are not only a marker of antiphospholipid syndrome but are directly involved in the pathogenesis of thrombosis. PMID:21245481
-
Rodriguez-Sanchez, Dariana Graciela; Flores-García, Mirthala; Silva-Platas, Christian; Rizzo, Sheryl; Torre-Amione, Guillermo; De la Peña-Diaz, Aurora; Hernández-Brenes, Carmen; García-Rivas, Gerardo
2015-01-01
Platelets play a pivotal role in physiological hemostasis. However, in coronary arteries damaged by atherosclerosis, enhanced platelet aggregation, with subsequent thrombus formation, is a precipitating factor in acute ischemic events. Avocado pulp (Persea americana) is a good source of bioactive compounds, and its inclusion in the diet as a source of fatty acid has been related to reduced platelet aggregability. Nevertheless, constituents of avocado pulp with antiplatelet activity remain unknown. The present study aims to characterize the chemical nature of avocado constituents with inhibitory effects on platelet aggregation. Centrifugal partition chromatography (CPC) was used as a fractionation and purification tool, guided by an in vitro adenosine diphosphate (ADP), arachidonic acid or collagen-platelet aggregation assay. Antiplatelet activity was initially linked to seven acetogenins that were further purified, and their dose-dependent effects in the presence of various agonists were contrasted. This process led to the identification of Persenone-C (3) as the most potent antiplatelet acetogenin (IC₅₀=3.4 mM) among the evaluated compounds. In vivo evaluations with Persenone A (4) demonstrated potential protective effects against arterial thrombosis (25 mg kg⁻¹ of body weight), as coagulation times increased (2-fold with respect to the vehicle) and thrombus formation was attenuated (71% versus vehicle). From these results, avocado may be referred to as a functional food containing acetogenin compounds that inhibit platelet aggregation with a potential preventive effect on thrombus formation, such as those that occur in ischaemic diseases.
-
International Nuclear Information System (INIS)
Bao Shiyao; Li Wen; He Guangren; Shao Guofu; Zhang Zhilin; Wu Jinchang
1995-05-01
The capacity of McAbSZ-51, which is specific for an α-granule membrane protein (GMP-140) expressed on the surface of activated platelets, to bind to the grafted human thrombus in rabbits was studied. The feasibility of imaging thrombus with 99m Tc-labelled McAbSZ-51 in the internal carotid artery of dog was also explored. The results showed that McAbSZ-51 could bind to the grafted human thrombus in rabbits. The thrombus in internal carotid artery was clearly discerned at 2 to 6 h after injection of 99m Tc-SZ-51, with the optimal imaging time at 2 to 4 h after injection. The radioactivity ratio of thrombus to blood was 6.03 +- 1.09 at 6 to 8 h after injection. It is thus concluded that by using the 99m Tc-labelled McAbSZ-51, the early and specific detection of thrombi formed in vivo was fairly possible and feasible. (3 figs., 1 tab.)
-
Directory of Open Access Journals (Sweden)
Kazuya Hosokawa
Full Text Available Dabigatran and rivaroxaban are novel oral anticoagulants that specifically inhibit thrombin and factor Xa, respectively. The aim of this study is to elucidate antithrombotic properties of these anticoagulant agents under arterial and venous shear conditions. Whole blood samples treated with dabigatran or rivaroxaban at 250, 500, and 1000 nM, with/without aspirin and AR-C66096, a P2Y12 antagonist, were perfused over a microchip coated with collagen and tissue thromboplastin at shear rates of 240 and 600 s(-1. Fibrin-rich platelet thrombus formation was quantified by monitoring flow pressure changes. Dabigatran at higher concentrations (500 and 1000 nM potently inhibited thrombus formation at both shear rates, whereas 1000 nM of rivaroxaban delayed, but did not completely inhibit, thrombus formation. Dual antiplatelet agents weakly suppressed thrombus formation at both shear rates, but intensified the anticoagulant effects of dabigatran and rivaroxaban. The anticoagulant effects of dabigatran and rivaroxaban were also evaluated under static conditions using thrombin generation (TG assay. In platelet-poor plasma, dabigatran at 250 and 500 nM efficiently prolonged the lag time (LT and moderately reduce peak height (PH of TG, whereas rivaroxaban at 250 nM efficiently prolonged LT and reduced PH of TG. In platelet-rich plasma, however, both anticoagulants efficiently delayed LT and reduced PH of TG. Our results suggest that dabigatran and rivaroxaban may exert distinct antithrombotic effects under flow conditions, particularly in combination with dual antiplatelet therapy.
-
Directory of Open Access Journals (Sweden)
Huzoor Akbar
Full Text Available Cdc42 and Rac1, members of the Rho family of small GTPases, play critical roles in actin cytoskeleton regulation. We have shown previously that Rac1 is involved in regulation of platelet secretion and aggregation. However, the role of Cdc42 in platelet activation remains controversial. This study was undertaken to better understand the role of Cdc42 in platelet activation.We utilized the Mx-cre;Cdc42(lox/lox inducible mice with transient Cdc42 deletion to investigate the involvement of Cdc42 in platelet function. The Cdc42-deficient mice exhibited a significantly reduced platelet count than the matching Cdc42(+/+ mice. Platelets isolated from Cdc42(-/-, as compared to Cdc42(+/+, mice exhibited (a diminished phosphorylation of PAK1/2, an effector molecule of Cdc42, (b inhibition of filopodia formation on immobilized CRP or fibrinogen, (c inhibition of CRP- or thrombin-induced secretion of ATP and release of P-selectin, (d inhibition of CRP, collagen or thrombin induced platelet aggregation, and (e minimal phosphorylation of Akt upon stimulation with CRP or thrombin. The bleeding times were significantly prolonged in Cdc42(-/- mice compared with Cdc42(+/+ mice.Our data demonstrate that Cdc42 is required for platelet filopodia formation, secretion and aggregation and therefore plays a critical role in platelet mediated hemostasis and thrombosis.
-
Panzenboeck, Adelheid; Winter, Max P; Schubert, Uwe; Voswinckel, Robert; Frey, Maria K; Jakowitsch, Johannes; Alimohammadi, Arman; Hobohm, Lukas; Mangold, Andreas; Bergmeister, Helga; Sibilia, Maria; Wagner, Erwin F; Mayer, Eckhard; Klepetko, Walter; Hoelzenbein, Thomas J; Preissner, Klaus T; Lang, Irene M
2015-01-01
Objective Restoration of patency is a natural target of vascular remodeling following venous thrombosis that involves vascular endothelial cells and smooth muscle cells as well as leukocytes. Acute pulmonary emboli usually resolve within six months. However, in some instances, thrombi transform into fibrous vascular obstructions, resulting in occlusion of the deep veins, or in chronic thromboembolic pulmonary hypertension (CTEPH). We proposed that dysregulated thrombus angiogenesis may contribute to thrombus persistence. Approach and Results Mice with an endothelial-cell-specific conditional deletion of vascular endothelial growth factor receptor 2/kinase insert domain protein receptor (VEGF-R2/Kdr) were utilized in a model of stagnant flow venous thrombosis closely resembling human deep vein thrombosis. Biochemical and functional analyses were performed on pulmonary endarterectomy specimens from patients with CTEPH, a human model of non-resolving venous thromboembolism. Endothelial cell-specific deletion of Kdr and subsequent ablation of thrombus vascularization delayed thrombus resolution. In accordance with these findings, organized human CTEPH thrombi were largely devoid of vascular structures. Several vessel-specific genes such as KDR, vascular endothelial cadherin and podoplanin were expressed at lower levels in white CTEPH thrombi than in organizing deep vein thrombi and organizing thrombi from aortic aneurysms. In addition, red CTEPH thrombi attenuated the angiogenic response induced by VEGF. Conclusions In the present work, we propose a mechanism of thrombus non-resolution demonstrating that endothelial cell-specific deletion of Kdr abates thrombus vessel formation, misguiding thrombus resolution. Medical conditions associated with the development of CTEPH may be compromising early thrombus angiogenesis. PMID:24526692
-
Joo, Jung-Chul; Seol, Myung Do; Yoon, Jin Won; Lee, Young Soo; Kim, Dong-Keun; Choi, Yong Hoon; Ahn, Hyo Seong; Cho, Wook Hyun
2013-03-01
Myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a multisystem clinical syndrome manifested by mitochondrial myopathy, encephalopathy, lactic acidosis and recurrent stroke-like episodes. A 27-year-old female with MELAS syndrome presented with cerebral infarction. Echocardiography revealed a thrombus attached to the apex of the hypertrophied left ventricle, with decreased systolic function. The embolism of the intracardiac thrombus might have been the cause of stroke. There should be more consideration given to the increased possibility of intracardiac thrombus formation when a MELAS patient with cardiac involvement is encountered.
-
Measurement of Thrombus Flux Using Transesophageal Echocardiography
Yamaguchi, Tadashi; Hirai, Kazuki; Aoki, Masami; Miyagi, Jin; Suzuki, Masahiko; Moriya, Hideshige; Hachiya, Hiroyuki
2006-05-01
Deep venous thrombosis (DVT) and pulmonary thromboembolism (PTE) are serious problem of total knee replacement (TKR). These diseases may be caused by a thrombus formed during the TKR operation. Therefore, understanding the flow volume of thrombus is important for curing and preventing PTE. In this paper, we tried to understanding the situation of the flow of thrombus by using transesophageal echocardiography movies. We applied the signal processing technique the FSET to extract the anomalous information from ultrasonic echo image. As a result of processing, the time change of the flow volume of thrombus was confirmed.
-
Directory of Open Access Journals (Sweden)
Naadiya Carrim
Full Text Available We have previously shown the presence of a TRAF4/p47phox/Hic5/Pyk2 complex associated with the platelet collagen receptor, GPVI, consistent with a potential role of this complex in GPVI-dependent ROS formation. In other cell systems, NOX-dependent ROS formation is facilitated by Pyk2, which along with its closely related homologue FAK are known to be activated and phosphorylated downstream of ligand binding to GPVI.To evaluate the relative roles of Pyk2 and FAK in GPVI-dependent ROS formation and to determine their location within the GPVI signaling pathway.Human and mouse washed platelets (from WT or Pyk2 KO mice were pre-treated with pharmacological inhibitors targeting FAK or Pyk2 (PF-228 and Tyrphostin A9, respectively and stimulated with the GPVI-specific agonist, CRP. FAK, but not Pyk2, was found to be essential for GPVI-dependent ROS production and aggregation. Subsequent human platelet studies with PF-228 confirmed FAK is essential for GPVI-mediated phosphatidylserine exposure, α-granule secretion (P-selectin (CD62P surface expression and integrin αIIbβ3 activation. To determine the precise location of FAK within the GPVI pathway, we analyzed the effect of PF-228 inhibition in CRP-stimulated platelets in conjunction with immunoprecipitation and pulldown analysis to show that FAK is downstream of Lyn, Spleen tyrosine kinase (Syk, PI3-K and Bruton's tyrosine kinase (Btk and upstream of Rac1, PLCγ2, Ca2+ release, PKC, Hic-5, NOX1 and αIIbβ3 activation.Overall, these data suggest a novel role for FAK in GPVI-dependent ROS formation and platelet activation and elucidate a proximal signaling role for FAK within the GPVI pathway.
-
Clinical evaluation of the platelet scintigraphy using indium-111 oxine
International Nuclear Information System (INIS)
Ishikawa, Nobuyoshi; Takeda, Tohoru; Nakajima, Kohtaroh; Satoh, Motohiro; Akisada, Masayoshi; Ijima, Hiroshi
1988-01-01
The clinical usefulness of autologous platelets labeled with Indium-111 oxine was evaluated by scintigraphy as a diagnostic procedure for the detection of various thrombotic disorders as well as in different aneurysms. The positivity was found to be satisfactory (80.0 %) in cases of aortic aneurysm while thoracic aneurysm showed comparatively poor accumulation. High positivity was also demonstrated in deep vein thrombosis. The complimentary role of this method for intracardiac thrombi to echocardiography was noted. The labeling procedure of indium-111 oxine was fairly easy to perform and the activity of labeled platelets was sustained enough to yield good results. In one case scintigraphy was performed successfully after 19 hours of angiography when a hot area of labeled platelets was seen at the puncture site. This method was therefore varified to be a sensitive and reliable method in the assessment of thrombus activity, and as it demonstrates the activity, its helpfulness in the conservative treatment of these disorders is warranted. (author)
-
Quantitation of thrombogenicity of hemodialyzer with technetium-99m and indium-111 labeled platelets
International Nuclear Information System (INIS)
Dewanjee, M.K.; Kapadvanjwala, M.; Ruzius, K.; Serafini, A.N.; Zilleruelo, G.E.; Sfakianakis, G.N.
1993-01-01
The platelet thrombogenicity of a hemodialyzer was quantified with 99m Tc- and 111 In-labeled platelets. The platelets collected from blood of Beagle dogs, Yorkshire pigs and humans were labeled with 111 In-tropolone (detergent-free) and 99m Tc-HMPAO. Hemodialysis was performed with a hollow-fiber dialyzer (HFD) in a flow-loop, the temperature maintained at 37 o C, with flow-rates of 7, 150 and 270 mL/min; after dialysis, HFD radioactivity was measured with an ionization chamber and imaged with a γ-camera. The dynamic processes of thrombosis and embolization from the hemodialyzer resulted in large standard deviations around the mean values of the adherent thrombus. In spite of this, the quantitation of comparative thrombogenicity with 111 In-and 99m Tc-labeled platelets suggests that both radionuclides could be used for measurement of device-induced thrombogenicity and estimation of prosthesis-induced thrombogenicity. (author)
-
Active Von Willebrand Factor, thrombocytopenia and thrombosis
Hulstein, J.J.J.
2006-01-01
Platelets and von Willebrand factor (VWF) are unable to interact in circulation. To induce an interaction, a conversion of VWF to a platelet-binding conformation is required. At higher shear stresses, the first step in thrombus formation is binding of VWF to the subendothelium. This results in
-
Improved Human Erythropoiesis and Platelet Formation in Humanized NSGW41 Mice
Directory of Open Access Journals (Sweden)
Susann Rahmig
2016-10-01
Full Text Available Human erythro-megakaryopoiesis does not occur in humanized mouse models, preventing the in vivo analysis of human hematopoietic stem cell (HSC differentiation into these lineages in a surrogate host. Here we show that stably engrafted KIT-deficient NOD/SCID Il2rg−/− KitW41/W41 (NSGW41 mice support much improved human erythropoiesis and platelet formation compared with irradiated NSG recipients. Considerable numbers of human erythroblasts and mature thrombocytes are present in the bone marrow and blood, respectively. Morphology, composition, and enucleation capacity of de novo generated human erythroblasts in NSGW41 mice are comparable with those in human bone marrow. Overexpression of human erythropoietin showed no further improvement in human erythrocyte output, but depletion of macrophages led to the appearance of human erythrocytes in the blood. Human erythropoiesis up to normoblasts and platelet formation is fully supported in NSGW41 mice, allowing the analysis of human HSC differentiation into these lineages, the exploration of certain pathophysiologies, and the evaluation of gene therapeutic approaches.
-
Measurement of thrombus flux using transesophageal Echocardiography
International Nuclear Information System (INIS)
Yamaguchi, Tadashi; Hirai, Kazuki; Aoki, Masami; Miyagi, Jin; Suzuki, Masahiko; Moriya, Hideshige; Hachiya Hiroyuki
2006-01-01
Deep venous thrombosis (DVT) and pulmonary thromboembolism (PTE) are serious problem of total knee replacement (TKR). These diseases may be caused by a thrombus formed during the TKR operation. Therefore, understanding the flow volume of thrombus is important for curing and preventing PTE. In this paper, we tried to understanding the situation of the flow of thrombus by using transesophageal echocardiography movies. We applied the signal processing technique the fiber structure extraction technique (FSET) to extract the anomalous information from ultrasonic echo image. As a result of processing, the time change of the flow volume of thrombus was confirmed. (author)
-
The effect of platelet lysate supplementation of a dextran-based hydrogel on cartilage formation.
Moreira Teixeira, Liliana S; Leijten, Jeroen C H; Wennink, Jos W H; Chatterjea, Anindita G; Feijen, Jan; van Blitterswijk, Clemens A; Dijkstra, Pieter J; Karperien, Marcel
2012-05-01
In situ gelating dextran-tyramine (Dex-TA) injectable hydrogels have previously shown promising features for cartilage repair. Yet, despite suitable mechanical properties, this system lacks intrinsic biological signals. In contrast, platelet lysate-derived hydrogels are rich in growth factors and anti-inflammatory cytokines, but mechanically unstable. We hypothesized that the advantages of these systems may be combined in one hydrogel, which can be easily translated into clinical settings. Platelet lysate was successfully incorporated into Dex-TA polymer solution prior to gelation. After enzymatic crosslinking, rheological and morphological evaluations were performed. Subsequently, the effect of platelet lysate on cell migration, adhesion, proliferation and multi-lineage differentiation was determined. Finally, we evaluated the integration potential of this gel onto osteoarthritis-affected cartilage. The mechanical properties and covalent attachment of Dex-TA to cartilage tissue during in situ gel formation were successfully combined with the advantages of platelet lysate, revealing the potential of this enhanced hydrogel as a cell-free approach. The addition of platelet lysate did not affect the mechanical properties and porosity of Dex-TA hydrogels. Furthermore, platelet lysate derived anabolic growth factors promoted proliferation and triggered chondrogenic differentiation of mesenchymal stromal cells. Copyright © 2012 Elsevier Ltd. All rights reserved.
-
Yang, Y; Zhang, W; Cheng, B
2017-01-20
Objective: To explore the effects of calcium gluconate and thrombin on the formation of platelet-rich gel (PRG) and the release of bioactive substances in human platelet-rich plasma (PRP) and the clinical significance. Methods: Six healthy blood donors who met the inclusion criteria were recruited in our unit from May to August in 2016. Platelet samples of each donor were collected for preparation of PRP. (1) PRP in the volume of 10 mL was collected from each donor and divided into thrombin activation group (TA, added with 0.5 mL thrombin solution in dose of 100 U/mL) and calcium gluconate activation group (CGA, added with 0.5 mL calcium gluconate solution in dose of 100 g/L) according to the random number table, with 5 mL PRP in each group. Then the PRP of the two groups was activated in water bath at 37 ℃ for 1 h. The formation time of PRG was recorded, and the formation situation of PRG was observed within 1 hour of activation. After being activated for 1 h, one part of PRG was collected to observe the distribution of fibrous protein with HE staining, and another part of PRG was collected to observe platelet ultrastructure under transmission electron microscope (TEM). After being activated for 1 h, the supernatant was collected to determine the content of transforming growth factor β(1, )platelet-derived growth factor BB (PDGF-BB), vascular endothelial growth factor, basic fibroblast growth factor (bFGF), epidermal growth factor, and insulin-like growth factorⅠby enzyme-linked immunosorbent assay. (2) Another 10 mL PRP from each donor was collected and grouped as above, and the platelet suspension was obtained after two times of centrifugation and resuspension with phosphate buffered saline, respectively. And then they were treated with corresponding activator for 1 h as that in experiment (1). Nanoparticle tracking analyzer was used to detect the concentrations of microvesicles with different diameters and total microvesicles derived from platelet. Data
-
Directory of Open Access Journals (Sweden)
Jacopo eBiasetti
2012-07-01
Full Text Available Abdominal Aortic Aneurysms (AAAs are frequently characterized by the presenceof an Intra-Luminal Thrombus (ILT known to influence biochemically and biomechanicallytheir evolution. ILT progression mechanism is still unclear and little is known regardingthe impact on this mechanism of the chemical species transported by blood flow.Chemical agonists and antagonists of platelets activation, aggregation, and adhesion andthe proteins involved in the coagulation cascade (CC may play an important role in ILTdevelopment. Starting from this assumption, the evolution of chemical species involvedin the CC, their relation to coherent vortical structures (VSs and their possible effect onILT evolution have been studied. To this end a fluido-chemical model that simulates theCC through a series of convection-diffusion-reaction (CDR equations has been developed.The model involves plasma-phase and surface bound enzymes and zymogens, and includesboth plasma-phase and membrane-phase reactions. Blood is modeled as a non-Newtonianincompressible fluid. VSs convect thrombin in the domain and lead to the high concentration observed in the distal portion of the AAA. This finding is in line with the clinicalobservations showing that the thickest ILT is usually seen in the distal AAA region. Theproposed model, due to its ability to couple the fluid and chemical domains, provides anintegrated mechanochemical picture that potentially could help unveil mechanisms of ILTformation and development.
-
Directory of Open Access Journals (Sweden)
Ye-Ming Lee
2012-01-01
Full Text Available Xanthohumol is the principal prenylated flavonoid in the hop plant (Humulus lupulus L.. Xanthohumol was found to be a very potent cancer chemopreventive agent through regulation of diverse mechanisms. However, no data are available concerning the effects of xanthohumol on platelet activation. The aim of this paper was to examine the antiplatelet effect of xanthohumol in washed human platelets. In the present paper, xanthohumol exhibited more-potent activity in inhibiting platelet aggregation stimulated by collagen. Xanthohumol inhibited platelet activation accompanied by relative [Ca2+]i mobilization, thromboxane A2 formation, hydroxyl radical (OH● formation, and phospholipase C (PLCγ2, protein kinase C (PKC, mitogen-activated protein kinase (MAPK, and Akt phosphorylation. Neither SQ22536, an inhibitor of adenylate cyclase, nor ODQ, an inhibitor of guanylate cyclase, reversed the xanthohumol-mediated inhibitory effect on platelet aggregation. Furthermore, xanthohumol did not significantly increase nitrate formation in platelets. This study demonstrates for the first time that xanthohumol possesses potent antiplatelet activity which may initially inhibit the PI3-kinase/Akt, p38 MAPK, and PLCγ2-PKC cascades, followed by inhibition of the thromboxane A2 formation, thereby leading to inhibition of [Ca2+]i and finally inhibition of platelet aggregation. Therefore, this novel role of xanthohumol may represent a high therapeutic potential for treatment or prevention of cardiovascular diseases.
-
Gündüz, Sabahattin; Özkan, Mehmet; Kalçik, Macit; Gürsoy, Ozan Mustafa; Astarcioğlu, Mehmet Ali; Karakoyun, Süleyman; Aykan, Ahmet Çağri; Biteker, Murat; Gökdeniz, Tayyar; Kaya, Hasan; Yesin, Mahmut; Duran, Nilüfer Ekşi; Sevinç, Deniz; Güneysu, Tahsin
2015-12-01
Distinguishing pannus and thrombus in patients with prosthetic valve dysfunction is essential for the selection of proper treatment. We have investigated the utility of 64-slice multidetector computed tomography (MDCT) in distinguishing between pannus and thrombus, the latter amenable to thrombolysis. Sixty-two (23 men, mean age 44±14 years) patients with suspected mechanical prosthetic valve dysfunction assessed by transesophageal echocardiography were included in this prospective observational trial. Subsequently, MDCT was performed before any treatment was started. Periprosthetic masses were detected by MDCT in 46 patients, and their attenuation values were measured as Hounsfield Units (HU). Patients underwent thrombolysis unless contraindicated, and those with a contraindication or failed thrombolysis underwent surgery. A mass which was completely lysed or surgically detected as a clot was classified as thrombus, whereas a mass which was surgically detected as tissue overgrowth was classified as pannus. A definitive diagnosis could be achieved in 37 patients with 39 MDCT masses (22 thrombus and 17 pannus). The mean attenuation value of 22 thrombotic masses was significantly lower than that in 17 pannus (87±59 versus 322±122; Ppannus from thrombus. Complete lysis was more common for masses with HUpannus overgrowth, whereas a lower value is associated with thrombus formation. A higher attenuation (HU>90) is associated with reduced lysis rates. © 2015 American Heart Association, Inc.
-
Anti-platelet activity of water dispersible curcuminoids in rat platelets.
Maheswaraiah, Anikisetty; Rao, Lingamallu Jaganmohan; Naidu, Kamatham Akhilender
2015-03-01
Curcuminoids are active principle of turmeric with plethora of health beneficial properties. In this study, we have evaluated for the first time the effect of water dispersible curcuminoids on rat platelet aggregation. Curcuminoids (10-30 µg/mL) significantly inhibited platelet aggregation induced by agonists viz., collagen, ADP and arachidonic acid. Curcuminoids were found to be two-fold more potent than curcumin in inhibiting platelet aggregation. Intracellular curcuminoid concentration was relatively higher than curcumin in rat platelets. Curcuminoids significantly attenuated thromboxane A2 , serotonin levels in rat platelets which play an important role in platelet aggregation. Curcuminoid treatment increased nitric oxide (NO) levels in platelets treated with agonists. Curcuminoids inhibited free radicals such as superoxide anion released from activated platelets, which ultimately inhibits platelet aggregation. Further, curcuminoids inhibited 12-lipoxygenase activity and formation of 12-hydroperoxyeicosatetraenoic acid (12-HPETE) in activated rat platelets which regulates platelet aggregation. The results suggest that curcuminoids have remarkable anti-platelet activity by modulating multiple mechanisms involved in platelet aggregation. Thus curcuminoids may have a therapeutic potential to prevent platelet activation related disorders. Copyright © 2015 John Wiley & Sons, Ltd.
-
International Nuclear Information System (INIS)
Yamashita, Atsushi; Zhao, Yan; Zhao, Songji
2013-01-01
Imaging modalities to assess atherosclerotic plaque thrombogenicity have not been established, so in this study the relationship between [ 18 F]-fluorodeoxyglucose ( 18 F-FDG) uptake and thrombus formation was investigated in rabbit atherosclerotic arteries. Atherosclerotic plaque was induced in the iliacofemoral artery by balloon injury and a 0.5% cholesterol diet. At 3 weeks after the first balloon injury, the arteries were visualized by 18 F-FDG positron emission tomography (PET) imaging 2 h after an 18 F-FDG infusion, and then arterial thrombus was induced by a second balloon injury of both iliacofemoral arteries. Imaging with 18 F-FDG-PET revealed significantly more radioactivity along the injured (0.63±0.12 standardized uptake value (SUV)max), than the contralateral non-injured artery (0.34±0.08 SUVmax, n=17, P 18 F-FDG uptake reflects the thrombogenicity of atherosclerotic plaque following balloon injury. (author)
-
Platelet function in brown bear (Ursus arctos compared to man
Directory of Open Access Journals (Sweden)
Särndahl Eva
2010-06-01
Full Text Available Abstract Background Information on hemostasis and platelet function in brown bear (Ursus arctos is of importance for understanding the physiological, protective changes during hibernation. Objective The study objective was to document platelet activity values in brown bears shortly after leaving the den and compare them to platelet function in healthy humans. Methods Blood was drawn from immobilized wild brown bears 7-10 days after leaving the den in mid April. Blood samples from healthy human adults before and after clopidogrel and acetylsalicylic acid administration served as control. We analyzed blood samples by standard blood testing and platelet aggregation was quantified after stimulation with various agonists using multiple electrode aggregometry within 3 hours of sampling. Results Blood samples were collected from 6 bears (3 females between 1 and 16 years old and from 10 healthy humans. Results of adenosine diphosphate, aspirin, and thrombin receptor activating peptide tests in bears were all half or less of those in humans. Platelet and white blood cell counts did not differ between species but brown bears had more and smaller red blood cells compared with humans. Conclusion Using three different tests, we conclude that platelet function is lower in brown bears compared to humans. Our findings represent the first descriptive study on platelet function in brown bears and may contribute to explain how bears can endure denning without obvious thrombus building. However, the possibility that our findings reflect test-dependent and not true biological variations in platelet reactivity needs further studies.
-
Dai, Bingyang; Li, Lan; Li, Qiangqiang; Song, Xiaoxiao; Chen, Dongyang; Dai, Jin; Yao, Yao; Yan, Wenjin; Teng, Huajian; Yang, Fang; Xu, Zhihong; Jiang, Qing
2017-07-01
: L-Arginine (L-arg), widely known as a substrate for endogenous nitric oxide synthesis, can improve endothelial function associated with the vasculature, inhibit platelet aggregation, and alter the activity of vascular smooth muscle cells. P-selectin is a membrane component of the platelet alpha-granule and the endothelial cell-specific Wiebel-Palade body that plays a central role in mediating interactions between platelets and both leukocytes and the endothelium. The experiment was designed to evaluate the effect of novel microspheres with L-arg targeting P-selectin on the formation of deep vein thrombosis and repair of vascular wall in a rat model. Thrombosis of the inferior vena cava was induced by applying a piece of filter paper (5 mm × 10 mm) saturated with 10% FeCl3 solution for 5 min. Targeted microspheres with L-arg, targeted microspheres with water, and saline were injected into the tail veins of the rats after 30 min of applying the filter paper saturated with 10% FeCl3 solution. The dry weight and length of the thrombus isolated from the inferior vena cava were significantly decreased in the group with L-arg in microsphere after 24 h. No significant differences in prothrombin time, activated partial thromboplastin time, thrombin time, and fibrinogen among the groups were indicated. Images revealed that apoptosis in the vascular wall was less in the group injected with targeted microspheres with L-arg than in the other two groups at 1 and 8 d postsurgery. Meanwhile, cell proliferation was considerably excessive in the group injected with L-arg wrapped in targeted microspheres. Therefore, these novel microspheres could decrease the formation of thrombus in the early stages and in the subsequent periods of thrombosis. The microspheres can also enhance the vitality of impaired endothelial cells and reduce cell apoptosis.
-
Granulocyte-platelet interactions and platelet fibrinogen receptor exposure
International Nuclear Information System (INIS)
Kornecki, E.; Ehrlich, Y.H.; Egbring, R.; Gramse, M.; Seitz, R.; Eckardt, A.; Lukasiewicz, H.; Niewiarowski, S.
1988-01-01
The authors have examined the interaction of human granulocyte elastase with human platelets. Incubation of human platelets with human granulocyte elastase exposed active fibrinogen-binding sites as evidenced by 125 I-labeled fibrinogen binding and spontaneous fibrinogen-induced platelet aggregation. The aggregation of platelets by fibrinogen occurred at low concentrations of human granulocyte elastase. Platelets pretreated with human granulocyte elastase exposed an average of 10,500 fibrinogen-binding sites per platelet, i.e., about one-third the number of binding sites exposed by optimal concentrations of ADP. With the use of a polyclonal antiplatelet membrane antibody, the glycoproteins IIb (GPIIb), IIIa (GPIIIa), and a 60,000-Da (60 kDa) protein (66 kDa in a reduced system) derived from GPIIIa were immunoprecipitated from the surface of detergent extracts of human 125 I-radiolabeled platelets pretreated with increasing concentrations of human granulocyte elastase. They conclude that (1) the proteolytic action of human granulocyte elastase on platelet GPIIIa results in the formation of two major hydrolytic products, and (2) human granulocyte elastase exposes active fibrongen-binding sites associated with the GPIIb/GPIIIa complex, resulting in direct platelet aggregation by fibrinogen
-
Langan, Stacey A; Navarro-Núñez, Leyre; Watson, Steve P; Nash, Gerard B
2017-07-20
Lymphatic endothelial cells (LEC) express the transmembrane receptor podoplanin whose only known endogenous ligand CLEC-2 is found on platelets. Both podoplanin and CLEC-2 are required for normal lymphangiogenesis as mice lacking either protein develop a blood-lymphatic mixing phenotype. We investigated the roles of podoplanin and its interaction with platelets in migration and tube formation by LEC. Addition of platelets or antibody-mediated crosslinking of podoplanin inhibited LEC migration induced by vascular endothelial growth factors (VEGF-A or VEGF-C), but did not modify basal migration or the response to basic fibroblast growth factor or epidermal growth factor. In addition, platelets and podoplanin crosslinking disrupted networks of LEC formed in co-culture with fibroblasts. Depletion of podoplanin in LEC using siRNA negated the pro-migratory effect of VEGF-A and VEGF-C. Inhibition of RhoA or Rho-kinase reduced LEC migration induced by VEGF-C, but had no further effect after crosslinking of podoplanin, suggesting that podoplanin is required for signaling downstream of VEGF-receptors but upstream of RhoA. Together, these data reveal for the first time that podoplanin is an intrinsic specific regulator of VEGF-mediated migration and network formation in LEC and identify crosslinking of podoplanin by platelets or antibodies as mechanisms to modulate this pathway.
-
Superior Venacava Thrombus-A Case Report
Directory of Open Access Journals (Sweden)
Bijay Sah
2016-03-01
Full Text Available Superior venacava (SVC thrombus is a condition requiring immediate diagnosis and treatment. SVC thrombus causes obstruction of blood flow through the SVC resulting in severe decrease in venous return from the head, neck and upper extremity to the heart. The presenting symptoms of SVC obstruction include headache, hoarseness of voice, dyspnea, and laryngeal edema, dizziness, swelling of face, neck, and upper extremity. We hereby present a case of SVC thrombus who presented to the casualty department of COMS-TH with features of SVC syndrome which was diagnosed and managed promptly.JCMS Nepal. 2016;12(1:33-5.
-
Lykov, A P; Bondarenko, N A; Surovtseva, M A; Kim, I I; Poveshchenko, O V; Pokushalov, E A; Konenkov, V I
2017-10-01
We studied the effects of human platelet-rich plasma and platelet lysate on proliferation, migration, and colony-forming properties of rat mesenchymal stem cells. Platelet-rich plasma and platelet lysate stimulated the proliferation, migration, and colony formation of mesenchymal stem cells. A real-time study showed that platelet-rich plasma produces the most potent stimulatory effect, while both platelet-rich plasma and platelet lysate stimulated migration of cells.
-
Balazy, M
1991-12-15
Radiolabeled cis-(+-)-5,6-epoxyeicosatrienoic acid (5(6)-EpETrE) was incubated with a suspension of isolated human platelets in order to study its metabolic fate. The epoxide slowly disappeared from the suspension and was completely metabolized within 30 min. After extraction and analysis by reverse-phase high performance liquid chromatography, seven metabolites were found. Addition of either indomethacin (0.01 mM, cyclooxygenase inhibitor) or BW755C (0.1 mM, cyclooxygenase/lipoxygenase inhibitor) to the incubations blocked the formation of four and six metabolites, respectively, 1,2-Epoxy-3,3,3-trichloropropane (inhibitor of microsomal epoxide hydrolase) failed to inhibit the formation of 5,6-dihydroxyeicosatrienoic acid (5,6-DiHETrE), a hydrolysis product of the precursor 5(6)-EpETrE. The metabolites were characterized by UV spectroscopy, negative ion chemical ionization liquid chromatography/mass spectrometry, gas chromatography/mass spectrometry and, in one instance, coelution with synthetic standard. Three primary platelet metabolites were structurally determined to be 5,6-epoxy-12-hydroxyeicosatrienoic acid, 5,6-epoxy-12-hydroxyheptadecadienoic acid, and a unique bicyclic metabolite, 5-hydroxy-6,9-epoxy-thromboxane B1, which originated from intramolecular hydrolysis of 5,6-epoxythromboxane-B1. This thromboxane analog was partially separated into stereoisomers and coeluted with the racemic synthetic standard in gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. Three other metabolites were characterized as 5,6,12-trihydroxyeicosatrienoic acid, 5,6,12-trihydroxyheptadecadienoic acid, and 5,6-dihydroxythromboxane-B1, and resulted from the hydrolysis of the corresponding epoxides rather than from the metabolism of 5,6-DiHETrE. The latter was not metabolized by platelet cyclooxygenase or lipoxygenase. The biosynthesis of two cyclooxygenase metabolites indicated the formation of unstable 5,6-epoxythromboxane-A1 as an intermediate
-
Carnevale, Roberto; Bartimoccia, Simona; Nocella, Cristina; Di Santo, Serena; Loffredo, Lorenzo; Illuminati, Giulio; Lombardi, Elisabetta; Boz, Valentina; Del Ben, Maria; De Marco, Luigi; Pignatelli, Pasquale; Violi, Francesco
2014-11-01
Platelets generate oxidized LDL (ox-LDL) via NOX2-derived oxidative stress. We investigated if once generated by activated platelets ox-LDL can propagate platelet activation. Experiments were performed in platelets from healthy subjects (HS), hyper-cholesterolemic patients and patients with NOX2 hereditary deficiency. Agonist-stimulated platelets from HS added with LDL were associated with a dose-dependent increase of reactive oxidant species and ox-LDL. Agonist-stimulated platelets from HS added with a fixed dose of LDL (57.14 μmol/L) or added with homogenized human atherosclerotic plaque showed enhanced ox-LDL formation (approximately +50% and +30% respectively), which was lowered by a NOX2 inhibitor (approximately -35% and -25% respectively). Compared to HS, ox-LDL production was more pronounced in agonist-stimulated platelet rich plasma (PRP) from hyper-cholesterolemic patients but was almost absent in PRP from NOX2-deficient patients. Platelet aggregation and 8-iso-PGF2α-ΙΙΙ formation increased in LDL-treated washed platelets (+42% and +53% respectively) and PRP (+31% and +53% respectively). Also, LDL enhanced platelet-dependent thrombosis at arterial shear rate (+33%) but did not affect platelet activation in NOX2-deficient patients. Platelet activation by LDL was significantly inhibited by CD36 or LOX1 blocking peptides, two ox-LDL receptor antagonists, or by a NOX2 inhibitor. LDL-added platelets showed increased p38MAPK (+59%) and PKC (+51%) phosphorylation, p47(phox) translocation to platelet membrane (+34%) and NOX2 activation (+30%), which were inhibited by ox-LDL receptor antagonists. Platelets oxidize LDL, which in turn amplify platelet activation via specific ox-LDL receptors; both effects are mediated by NOX2 activation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
-
Directory of Open Access Journals (Sweden)
Yu. F. Salakhova
2011-01-01
Full Text Available The thrombus formation in the left ventricle (LV cavity is a frequent complication of myocardial infarction (MI as well as a risk factor for peripheral arterial embolism. Probability of intraventricular thrombus depends on MI location and its therapy. A case of coronary embolism in a patient with anterior MI and thrombus in the LV aneurysm is considered in details. Successful percutaneous coronary intervention (PCI in the first 90 minutes after admission was performed. Decision to appoint a three-component antithrombotic therapy (acetylsalicylic acid, clopidogrel, warfarin was made on the 4th day of disease onset taking into account the combination of MI, stent placement in the anterior interventricular artery and the presence of left ventricular aneurysm with parietal thrombus. Recurrence of MI developed on the 9th day of disease onset. Aspiration thromboembolectomy was performed taking into account thrombosis of two coronary arteries. Warfarin therapy was discontinued in connection with subsequent clot lysis and development of not intensive nosebleed. Subsequent MI course was uneventful. In conclusion, even in spite of the timely achievement of PCI and early reperfusion, MI course can be complicated by thrombosis of the left ventricle and subsequent development of thromboembolic complications.
-
Platelets Express Activated P2Y12 Receptor in Patients With Diabetes Mellitus.
Hu, Liang; Chang, Lin; Zhang, Yan; Zhai, Lili; Zhang, Shenghui; Qi, Zhiyong; Yan, Hongmei; Yan, Yan; Luo, Xinping; Zhang, Si; Wang, Yiping; Kunapuli, Satya P; Ye, Hongying; Ding, Zhongren
2017-08-29
Platelets from patients with diabetes mellitus are hyperactive. Hyperactivated platelets may contribute to cardiovascular complications and inadequate responses to antiplatelet agents in the setting of diabetes mellitus. However, the underlying mechanism of hyperactivated platelets is not completely understood. We measured P2Y 12 expression on platelets from patients with type 2 diabetes mellitus and on platelets from rats with diabetes mellitus. We also assayed platelet P2Y 12 activation by measuring cAMP and VASP phosphorylation. The antiplatelet and antithrombotic effects of AR-C78511 and cangrelor were compared in rats. Finally, we explored the role of the nuclear factor-κB pathway in regulating P2Y 12 receptor expression in megakaryocytes. Platelet P2Y 12 levels are 4-fold higher in patients with type 2 diabetes mellitus compared with healthy subjects. P2Y 12 expression correlates with ADP-induced platelet aggregation (r=0.89, P diabetes mellitus is constitutively activated. Although both AR-C78511, a potent P2Y 12 inverse agonist, and cangrelor have similar antiplatelet efficacy on platelets from healthy subjects, AR-C78511 exhibits more powerful antiplatelet effects on diabetic platelets than cangrelor (aggregation ratio 36±3% versus 49±5%, respectively, P diabetes mellitus than cangrelor (thrombus weight 4.9±0.3 mg versus 8.3±0.4 mg, respectively, P diabetes mellitus. Platelet P2Y 12 receptor expression is significantly increased and the receptor is constitutively activated in patients with type 2 diabetes mellitus, which contributes to platelet hyperactivity and limits antiplatelet drug efficacy in type 2 diabetes mellitus. © 2017 American Heart Association, Inc.
-
Nishiyama, U; Kuwaki, T; Akahori, H; Kato, T; Ikeda, Y; Miyazaki, H
2005-02-01
Previous in vitro studies demonstrated that thrombopoietin (TPO) acts on platelets to activate a variety of intracellular signaling pathways and to enhance platelet sensitivity to multiple agonists. Little is known, however, about whether TPO exerts prothrombotic effects in vivo. The aim of this study was to examine the effects of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), a pegylated N-terminal domain of human TPO, in a rat model of venous thrombosis. A microthrombus was photochemically induced on the vessel wall of a mesenteric venule, but the vessel was not occluded by it. A single intravenous injection of PEG-rHuMGDF (3 microg kg(-1)) after the thrombus generation into normal rats enhanced the thrombus size, resulting in transient thrombotic occlusion in the majority of rats. Stimulatory effects on thrombus growth were also observed following administration of glycosylated recombinant human full-length TPO (6 microg kg(-1)). In rats rendered thrombocytopenic by total body irradiation, however, PEG-rHuMGDF, even at 300 microg kg(-1), did not induce a significant increase in thrombus size or thrombotic occlusion. Platelets from thrombocytopenic rats had decreased surface levels of c-Mpl and decreased sensitivity to PEG-rHuMGDF in an in vitro aggregation response. Thus, decreased prothrombotic effects of PEG-rHuMGDF in thrombocytopenic rats might be the result not only of low platelet counts but also of decreased platelet reactivity to PEG-rHuMGDF. These results indicate that PEG-rHuMGDF has little effect on venous thrombus formation in thrombocytopenic states associated with high endogenous TPO levels.
-
Södergren, A L; Tynngård, N; Berlin, G; Ramström, S
2016-02-01
Storage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation. Activation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lysosome-associated membrane protein-1 (LAMP-1), P-selectin and phosphatidylserine (PS) exposure were assessed by flow cytometry on platelets in different subpopulations in resting state or following stimulation with platelet agonists (cross-linked collagen-related peptide (CRP-XL), PAR1- and PAR4-activating peptides). The ability to form subpopulations upon activation was significantly decreased already at day 5 for some agonist combinations. The agonist-induced exposure of PS and LAMP-1 also gradually decreased with time. Spontaneous exposure of P-selectin and PS increased with time, while spontaneous LAMP-1 exposure was unchanged. In addition, agonist-induced LAMP-1 expression clearly discriminated platelet concentrates with reduced swirling from those with retained swirling. This suggests that LAMP-1 could be a good marker to capture changes in activation capacity in stored platelets. The platelet activation potential seen as LAMP-1 exposure and fragmentation into platelet subpopulations is potential sensitive markers for the platelet storage lesion. © 2015 International Society of Blood Transfusion.
-
DEFF Research Database (Denmark)
Pleines, Irina; Eckly, Anita; Elvers, Margitta
2010-01-01
formation and exocytosis in various cell types, but its exact function in platelets is not established. Here, we show that the megakaryocyte/platelet-specific loss of Cdc42 leads to mild thrombocytopenia and a small increase in platelet size in mice. Unexpectedly, Cdc42-deficient platelets were able to form...
-
Karmohapatra, Soumendra K; Chakraborty, Kushal; Kahn, Nighat N; Sinha, Asru K
2007-11-01
Aspirin, a well-known inhibitor of platelet aggregation, is extensively used for the prevention/treatment of coronary artery disease. The beneficial and antithrombotic effects of the compound are related to the inhibition of platelet cyclooxygenase. It is currently believed that aspirin has no effect on the formed thrombus, which results in coronary artery disease. It was found that the exposure of platelets to 4.0 microM aspirin either in vitro or in vivo resulted in fibrinolysis of the formed "clot" produced by the recalcification of platelet-rich plasma due to the production of NO in these cells by the compound. The lysis of clot in the presence of aspirin was found to be related to the fibrinolysis with simultaneous appearance of fibrin degradation products due to the generation of serine proteinase activity by NO in the assay mixture. The aspirin activated nitric oxide synthase that catalyzed the synthesis of NO in platelets was solubilized by Triton X-100 treatment and purified to homogeneity by chromatography on DEAE cellulose and Sephadex G-50 columns. The enzyme was found to be a single chain polypeptide with M.W. 19 kDa. The treatment of human plasminogen with NO was found to directly activate the zymogen to plasmin with the production of preactivation peptide in the absence of cofactors, or cells without the formation of cyclic GMP in the assay mixture. (c) 2007 Wiley-Liss, Inc.
-
Hypersensitivity to thrombin of platelets from hypercholesterolemic rats
International Nuclear Information System (INIS)
Winocour, P.D.; Rand, M.L.; Kinlough-Rathbone, R.L.; Mustard, J.F.
1986-01-01
Hypersensitivity of platelets to thrombin has been associated with hypercholesterolemia. The authors have examined the mechanisms involved in this hypersensitivity. Rats were given diets rich in milk fat and containing added cholesterol and taurocholate to produce hypercholesterolemia (HC) (262 +/- 25 mg%) or added sitosterol as a normocholesterolemic control (NC) (89 +/- 6 mg%). Washed platelets were prelabelled with 14 C-serotonin. In the presence of acetylsalicyclic acid (ASA) (to inhibit thromboxane A 2 (TXA 2 ) formation) and creatine phosphate/creatine phosphokinase (CP/CPK) (to remove released ADP), HC platelets aggregated more (26 +/- 1%) and released more 14 C (9.1 +/- 2.0%) than NC platelets (aggregation: 0%, p 14 C release: 1.5 +/- 0.5%, p 2 formation is involved in the hypersensitivity of HC platelets to thrombin. Total binding of 125 I-thrombin to HC platelets was less than that to NC platelets but HC platelets were smaller and had less protein than NC platelets; the thrombin binding per mg platelet protein was the same for HC and NC platelets, indicating that hypersensitivity to thrombin of HC platelets does not result from increased thrombin binding. Thus, hypersensitivity of HC platelets to thrombin is not due to TXA 2 formation, the action of released ADP or increased thrombin binding
-
Shaya, S A; Saldanha, L J; Vaezzadeh, N; Zhou, J; Ni, R; Gross, P L
2016-01-01
ESSENTIALS: Does thrombus stability alter the presentation of venous thromboembolism and do anticoagulants alter this? In a murine model, we imaged a femoral vein thrombus and quantified emboli in the pulmonary arteries. Dabigatran decreases thrombus stability via factor XIII increasing embolization and pulmonary emboli. This cautions against the unapproved use of dabigatran for acute initial treatment of deep vein thrombosis. Venous thromboembolism (VTE) is a collective term for deep vein thrombosis (DVT) and pulmonary embolism (PE). Thrombus instability possibly contributes to progression of DVT to PE, and direct thrombin inhibitors (DTIs) may alter this. To develop a model to assess thrombus stability and its link to PE burden, and identify whether DTIs, in contrast to low-molecular-weight heparin (LMWH), alter this correlation. Twelve minutes after ferric chloride-induced thrombus formation in the femoral vein of female mice, saline, dalteparin (LMWH) or dabigatran (DTI) was administered. Thrombus size and embolic events breaking off from the thrombus were quantified before treatment and at 10-min intervals after treatment for 2 h using intravital videomicroscopy. Lungs were stained for the presence of PE. Thrombus size was similar over time and between treatment groups. Total and large embolic events and pulmonary emboli were highest after treatment with dabigatran. Variations in amounts of pulmonary embolic events were not attributed to variations in thrombus size. Large embolic events correlated with the number of emboli per lung slice independent of treatment. Embolization in factor XIII deficient (FXIII(-/-) ) saline-treated mice was greater than that in wild-type (WT) saline-treated mice, but was similar to WT dabigatran-treated mice. We have developed a mouse model of VTE that can quantify emboli and correlate this with PE burden. Consistent with clinical data, dabigatran, a DTI, acutely decreases thrombus stability and increases PE burden compared with
-
The interaction of thrombin with platelet protease nexin
International Nuclear Information System (INIS)
Knupp, C.L.
1989-01-01
Thrombin interacts with a platelet protein which is immunologically related to fibroblast protease nexin and has been termed platelet protease nexin I (PNI). Conflicting hypotheses about the relationship of the thrombin-PNI complex formation to platelet activation have been proposed. The studies presented here demonstrate that the platelet-associated and supernatant complexes with added 125I-thrombin are formed only under conditions which produce platelet activation in normal and chymotrypsin-modified platelets. The platelet-associated complex is formed prior to the appearance of complexes in supernatants. Appearance of the supernatant complex coincides with the appearance of thrombospondin in the reaction supernatants. Excess native thrombin, dansylarginine N-(3-ethyl-1,5-pentanediyl) amide or hirudin can prevent radiolabeled platelet-associated complex formation if added before 125I-thrombin. DAPA or hirudin can prevent or dissociate complex formation if added up to one minute after thrombin but not at later time points. The surface associated complex is accessible to trypsin although a portion remains with the cytoskeletal proteins when thrombin-activated platelets are solubilized with Triton X 100. The surface-associated complex formation parallels many aspects of the specific measurable thrombin binding, yet it does not appear to involve other identified surface glycoprotein thrombin receptors or substrates. Although the time course of appearance of the complexes in supernatants is consistent with other data which suggest that PNI may be released from platelet granules during platelet activation, other explanations for the appearance of PNI on the platelet surface and in supernatants during platelet activation are possible
-
APTT- A SCREENING TEST FOR HYPERCOAGULABILITY IN TYPE ...
African Journals Online (AJOL)
Esem
disorders, Cancer and hyperthyroidism were excluded from the ... the evacuated blood collection system. 3 ml of .... Fibrinogen may induce thrombus formation by affecting platelets and ... and megakaryocytes throughout the body (24). Levels ...
-
Directory of Open Access Journals (Sweden)
Magdalena Riedl
2017-01-01
Discussion: Therefore, our findings of (i neutrophils adhering to complement-activated endothelial cells, (ii the formation of neutrophil-platelet aggregates on endothelial cells, and (iii the ability of aHUS serum to induce similar effects identify a possible role for neutrophils in aHUS manifestation.
-
Detection of extracellular genomic DNA scaffold in human thrombus
DEFF Research Database (Denmark)
Oklu, Rahmi; Albadawi, Hassan; Watkins, Michael T
2012-01-01
into thrombus remodeling. MATERIALS AND METHODS: Ten human thrombus samples were collected during cases of thrombectomy and open surgical repair of abdominal aortic aneurysms (five samples 1 y old). Additionally, an acute murine hindlimb ischemia model was created to evaluate...... thrombus samples in mice. Human sections were immunostained for the H2A/H2B/DNA complex, myeloperoxidase, fibrinogen, and von Willebrand factor. Mouse sections were immunostained with the H2A antibody. All samples were further evaluated after hematoxylin and eosin and Masson trichrome staining. RESULTS......: An extensive network of extracellular histone/DNA complex was demonstrated in the matrix of human ex vivo thrombus. This network is present throughout the highly cellular acute thrombus. However, in chronic thrombi, detection of the histone/DNA network was predominantly in regions of low collagen content...
-
Energy Technology Data Exchange (ETDEWEB)
Yamada, Makoto; Onishi, Kenji; Fukunami, Masatake and others
1988-12-01
Twenty patients in whom intracardiac thrombi were detected by indium-111 platelet scintigraphy (the first platelet scintigraphy) were prospectively studied to examine the effect of warfarin therapy under full dose on the intracardiac thrombogenecity. Eleven patients (group I) who received 2-6 mg/day of warfarin and 9 patients (group II) who did not received warfarin had the second platelet scintigraphies 14-71 days after the first platelet scintigraphies. In group I, 10 platelet scintigraphies became negative and one remained positive for intracardiac thrombi after administration of warfarin, while in group II 8 platelet scintigraphies remained positive and only one changed to negative. The incidence of negative image at the second platelet scintigraphy was significantly lower in group II than that in group I. In group I, the degree of accumulation of platelets onto the surface of the thrombus (%IE), showed significant reduction (0.69+-0.48 to 0.11+-0.21) after warfarin therapy, while in group II %IE at the second scintigraphy (1.07+-1.03) were not significantly different from those at the first scintigraphy (1.13+-0.79). These results indicated that warfarin therapy under full dose inhibited the deposition of platelets on the intracardiac thrombi and thrombogenecity in the patients with intracardiac thrombi which were detected by indium-111 platelet scintigraphy.
-
International Nuclear Information System (INIS)
Yamada, Makoto; Onishi, Kenji; Fukunami, Masatake
1988-01-01
Twenty patients in whom intracardiac thrombi were detected by indium-111 platelet scintigraphy (the first platelet scintigraphy) were prospectively studied to examine the effect of warfarin therapy under full dose on the intracardiac thrombogenecity. Eleven patients (group I) who received 2-6 mg/day of warfarin and 9 patients (group II) who did not received warfarin had the second platelet scintigraphies 14-71 days after the first platelet scintigraphies. In group I, 10 platelet scintigraphies became negative and one remained positive for intracardiac thrombi after administration of warfarin, while in group II 8 platelet scintigraphies remained positive and only one changed to negative. The incidence of negative image at the second platelet scintigraphy was significantly lower in group II than that in group I. In group I, the degree of accumulation of platelets onto the surface of the thrombus (%IE), showed significant reduction (0.69±0.48 to 0.11±0.21) after warfarin therapy, while in group II %IE at the second scintigraphy (1.07±1.03) were not significantly different from those at the first scintigraphy (1.13±0.79). These results indicated that warfarin therapy under full dose inhibited the deposition of platelets on the intracardiac thrombi and thrombogenecity in the patients with intracardiac thrombi which were detected by indium-111 platelet scintigraphy. (author)
-
Indium-111 platelet scintigraphy in carotid disease
International Nuclear Information System (INIS)
Branchereau, A.; Bernard, P.J.; Ciosi, G.; Bazan, M.; de Laforte, C.; Elias, A.; Bouvier, J.L.
1988-01-01
Forty-five patients (35 men, 10 women) undergoing carotid surgery had Indium-111 platelet scintigraphy as part of their preoperative work-up. Imaging was performed within three hours after injection of the Indium-111. A second series of views was obtained 24 hours later and repeated at 24 hour intervals for two days. Of 54 scintigrams, 22 were positive and 32 negative. Positive results were defined as a twofold or more increase in local activity on a visualized carotid after 24 hours. The sensitivity of the method was 41%, intraoperatively, and the specificity, 100%. The low sensitivity places this method behind sonography and duplex-scanning for screening patients for surgery. We believe that indications for platelet scintigraphy are limited to: 1. Repeated transient ischemic attacks in the same territory with minimal lesions on arteriography and non-homogeneous plaque on duplex scan; 2. Symptomatic patients being treated medically as a possible argument for surgery; 3. Determining therapeutic policy for patients having experienced a transient ischemic attack with a coexisting intracardiac thrombus
-
International Nuclear Information System (INIS)
Machac, J.; Horowitz, S.F.; Goldsmith, S.J.; Fuster, V.
1984-01-01
Indium-111 labeled platelet imaging is a tool for detection of thrombus formation in vascular spaces. Dual isotope blood pool subtraction may help differentiate focal platelet accumulation from blood pool activity. This study used a computer model to calculate the minimum excess-to-blood pool platelet ratio (EX/BP) and the optimum dual isotope imaging times under varied conditions of lesion size. The model simulated usual human imaging doses of 500 μCi of In-111 platelets and 5mCi of Tc-99m labeled RBCs giving a reference cardiac blood pool region (100cc) of 10000 cpm for Tc-99m and 500 cpm for In-111. The total imaging time was fixed at 20 minutes, while the two isotope imaging times (TIn/TTc) were varied, as were the simulated lesion size (cc) and EX/BP. The relative error of the excess counts was calculated using propagation of error theory. At the critical level of detection, where the excess lesion counts equal 3 times the standard deviation, the optimum TIn/TTc and minimum Ex/BP were determined for each lesion size. For the smallest lesion size (0.1cc), the minimum detectable EX/BP ratio was 1.6, with the best TIn/TTC ratio of 18/2 minutes, and for large lesions, an EX/BP of 0.1, with a TIn/TTc of 16/4. This model provides an estimate of the sensitivity and optimizes imaging times in dual isotope subtraction platelet imaging. The model is adaptable to varying isotope doses, total imaging times and lesion size. This information will be helpful in future in- vivo imaging studies of intravascular thrombi in humans
-
Contemporary management of symptomatic primary aortic mural thrombus.
Verma, Himanshu; Meda, Narendranadh; Vora, Simit; George, Robbie K; Tripathi, Ramesh K
2014-12-01
Primary aortic mural thrombus (PAMT) is an uncommon condition but an important source of noncardiogenic emboli with a difficult diagnosis and a high rate of complications, including high mortality. We report our experience of thromboembolic disease from PAMT and review its contemporary management. Retrospective analysis of prospectively collected data of all patients who presented with acute occlusion of a limb or visceral vessels between January 2011 and September 2013 was performed. A total of 88 patients presented with acute occlusion of the extremities or visceral arteries. All underwent extensive evaluation for the possible source of the embolism. Of these 88 patients, 19 patients (mean age, 41.2 years; male:female ratio, 1:2.1) were found to have aortic mural thrombus as the source of distal embolism. Thrombus was located in the thoracic aorta in 10 patients, in the perivisceral aorta in three patients, and in the infrarenal aorta in six patients. Thrombus in the thoracic aorta was treated with stent grafts in four patients, bare metal stents in three patients, and anticoagulation alone in two patients. In the suprarenal abdominal aorta, all three patients underwent trapdoor aortic thrombectomy. Infrarenal aortic thrombus was managed by aortobifemoral embolectomy in two patients, aortic stenting in two patients, surgical thrombectomy in one patient, and anticoagulation alone in one patient. Successful treatment, defined as freedom from further embolic events or recurrence of thrombus, was achieved in 14 of 19 patients (76.4%) with a mean follow-up period of 16.2 months (range, 2-28 months). There were four (21%) thrombus-related deaths, all due to primary thromboembolic insults. One patient needed a below-knee amputation because of a recurrent thrombotic episode. Symptomatic PAMT is an uncommon but important source of noncardiogenic embolus. It appears to occur more frequently in young women. Endovascular coverage of the aortic thrombus, when feasible
-
Lin, S. S.; Tiong, I. Y.; Asher, C. R.; Murphy, M. T.; Thomas, J. D.; Griffin, B. P.
2000-01-01
Identification of thrombus-related mechanical prosthetic valve dysfunction (MPVD) has important therapeutic implications. We sought to develop an algorithm, combining clinical and echocardiographic parameters, for prediction of thrombus-related MPVD in a series of 53 patients (24 men, age 52 +/- 16 years) who had intraoperative diagnosis of thrombus or pannus from 1992 to 1997. Clinical and echocardiographic parameters were analyzed to identify predictors of thrombus and pannus. Prevalence of thrombus and diagnostic yields relative to the number of predictors were determined. There were 22 patients with thrombus, 19 patients with pannus, and 12 patients with both. Forty-two of 53 masses were visualized using transesophageal echocardiography (TEE), including 29 of 34 thrombi or both thrombi and panni and 13 of 19 isolated panni. Predictors of thrombus or mixed presentation include mobile mass (p = 0.009), attachment to occluder (p = 0.02), elevated gradients (p = 0.04), and an international normalized ratio of or = 1 predictor. The prevalence of thrombus in the presence of or = 3 predictors is 14%, 69%, and 91%, respectively. Thus, TEE is sensitive in the identification of abnormal mass in the setting of MPVD. An algorithm based on clinical and transesophageal echocardiographic predictors may be useful to estimate the likelihood of thrombus in the setting of MPVD. In the presence of > or = 3 predictors, the probability of thrombus is high.
-
Södergren, Anna; Tynngård, Nahreen; Berlin, Gösta; Ramström, Sofia
2016-01-01
Background and ObjectivesStorage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation. Materials and MethodsActivation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lyso...
-
International Nuclear Information System (INIS)
Dormehl, I.C.; Du Plessis, M.; Jacobs, D.J.; Pretorius, J.P.; Franz, R.C.
1985-01-01
The diagnostic efficiency of autologous sup(111I)n-labelled platelets (ILP) as a scanning agent in deep veinthrombosis (DVT) was investigated in 24 South African baboons (Papio ursinus). Thrombi were surgically induced by stasis, intimal injury and the injection of thrombin in the common femoral veins of adult baboons. The thrombi were allowed to age for 1, 2, 4, 8, 24, 48 and 72 h before injecting the ILP. Scanning was done with a large field gamma camera at 10 min post injection and again at 2, 4, 6, 8, 10, 14, 24, 48 and 72 h. Time-activity curves were thus obtained and it was possible to establish an optimal time after injection of the ILP to scan for each group of thrombi. The results indicate that only the younger thrombi (1-8 h after thrombus formation) were detected. Twenty-four hour and older thrombi were not visualised. A favourable time to scan in the case of the younger thrombi appeared to be approximately 20 h after the injection of ILP. However, the thrombus age limitation still impairs the diagnostic efficiency of the procedure. (orig.)
-
Directory of Open Access Journals (Sweden)
Brkovic Zoran
2005-11-01
Full Text Available Abstract The presence of thrombi in the atherosclerotic and/or aneurysmatic aorta with peripheral arterial embolism is a common scenario. Thrombus formation in a morphologically normal aorta, however, is a rare event. A 50 years old woman was admitted to the mergency department for pain, coldness, and anesthesia in the the left foot. She had a 25 years history of cigarette smoking, a history of postmenopausal hormone replacement therapy (HRT, hypercholesterolemia and hyperfibrinogenemia. An extensive serologic survey for hypercoagulability, including antiphospholipid antibodies, and vasculitis disorders was negative. Transesophageal echocardiography revealed a large, pedunculated and hypermobile thrombus attached to the aortic wall 5 cm distal of the left subclavian artery. The patient was admitted to the surgery department, where a 15 cm long fresh, parietal thrombus could be removed from the aorta showing no macroscopic wall lesions or any other morphologic abnormalities. This case report demonstrates the possibility of evolving a large, pedunculated thrombus in a morphologically intact aorta in a postmenopausal woman with thrombogenic conditions such as hyperfibrinogenemia, hypercholesterolemia, smoking and HRT. For these patients, profiling the individual risk and weighing the benefits against the potential risks is warranted before prescribing HRT.
-
Kraft, Peter; Schuhmann, Michael K; Fluri, Felix; Lorenz, Kristina; Zernecke, Alma; Stoll, Guido; Nieswandt, Bernhard; Kleinschnitz, Christoph
2015-12-01
Despite the medical and socioeconomic effect of ischemic stroke and extensive preclinical research, treatment options for ischemic stroke are limited. We recently identified and characterized essential steps of thrombus formation in stroke and demonstrated that inhibition of the platelet glycoprotein (GP) receptors Ib and VI, but not IIb/IIIa, protects young and healthy mice from ischemic neurodegeneration. Whether these findings translate to the clinic remains unclear. Considering that the typical stroke patient is elderly with comorbidity, we aimed to analyze the efficacy and safety of novel preclinical antithrombotics in adult and comorbid mice with acute experimental stroke. We subjected adult, healthy, atherosclerotic (Ldlr(-/-)), diabetic (streptozotocin treated), and hypertensive (RenTgMK) mice to a 60-minute transient middle cerebral artery occlusion. Animals were pretreated with anti-GPVI antibodies or treated 1 hour after stroke induction with anti-GPIb or anti-GPIIb/IIIa antigen-binding fragments, respectively. Isotype treatment served as control. Twenty-four hours after transient middle cerebral artery occlusion, we visually assessed the intracerebral hemorrhage rate and measured infarct volumes (using 2,3,5-triphenyltetrazolium chloride-stained brain slices) and functional outcome (using Bederson and grip-test scores). GPIb and GPVI inhibition protected the mice from ischemic stroke without increasing bleeding complications. In contrast, GPIIb/IIIa inhibition was not protective but increased the intracerebral hemorrhage rate. Inhibition of early steps of thrombus formation protects adult and comorbid mice from ischemic stroke. The use of clinically meaningful mouse strains might improve the translation of preclinical stroke research to the clinic. © 2015 American Heart Association, Inc.
-
111In platelet imaging of left ventricular thrombi. Predictive value for systemic emboli
International Nuclear Information System (INIS)
Stratton, J.R.; Ritchie, J.L.
1990-01-01
To determine whether a positive indium 111 platelet image for a left ventricular thrombus, which indicates ongoing thrombogenic activity, predicts an increased risk of systemic embolization, we compared the embolic rate in 34 patients with positive 111 In platelet images with that in 69 patients with negative images during a mean follow-up of 38 +/- 31 (+/- SD) months after platelet imaging. The positive and negative image groups were similar with respect to age (59 +/- 11 vs. 62 +/- 10 years), prevalence of previous infarction (94% vs. 78%, p less than 0.05), time from last infarction (28 +/- 51 vs. 33 +/- 47 months), ejection fraction (29 +/- 14 vs. 33 +/- 14), long-term or paroxysmal atrial fibrillation (15% vs. 26%), warfarin therapy during follow-up (26% vs. 20%), platelet-inhibitory therapy during follow-up (50% vs. 33%), injected 111 In dose (330 +/- 92 vs. 344 +/- 118 microCi), and latest imaging time (greater than or equal to 48 hours in all patients). During follow-up, embolic events occurred in 21% (seven of 34) of patients with positive platelet images for left ventricular thrombi as compared with 3% (two of 69) of patients with negative images (p = 0.002). By actuarial methods, at 42 months after platelet imaging, only 86% of patients with positive images were embolus free as compared with 98% of patients with negative images (p less than 0.01)
-
International Nuclear Information System (INIS)
Farlow, D.C.; Ezekowitz, M.D.; Rao, S.R.; Martinez, C.; Denny, D.F.; Morse, S.S.; Decho, J.S.; Wackers, F.; Strauss, E.
1989-01-01
Indium-111 platelet scintigraphy accurately detects acute deep venous thrombosis in asymptomatic high-risk patients and may be used as a surveillance test. However, its value in symptomatic patients and its accuracy early after platelet injection are not satisfactorily established. The latter is important for timely institution of therapy. Accordingly, 65 patients (67 limbs) with suspected deep venous thrombosis (symptom duration 8 +/- 10 days, mean +/- standard deviation) were prospectively studied with platelet scintigraphy and contrast venography. Platelets were labeled with 405 +/- 101 mCi indium-111 oxine. The labeling efficiency was 80 +/- 10%. All images were acquired within 120 minutes after intravenous administration of the platelet suspension. Both platelet scintigraphy and venography were interpreted independently by 2 blinded observers (for each technique). Five separate analyses were performed. Each scintigraphic reader was compared to each venographic reader. A fifth analysis--consisting of readings with blinded agreement of both readings of the platelet scans and both readings of the venograms--was performed. Interobserver agreement was 92% for venography and 79% for scintigraphy. Excluding anticoagulated patients, the sensitivity of platelet scintigraphy was between 38 and 46% and the specificity was between 92 and 100%. Thus, early imaging of labeled platelets for the diagnosis of symptomatic deep venous thrombosis carries a high specificity but a much lower sensitivity. It is speculated that the low sensitivity is related to the inactivity of the thrombus. This may suggest that early imaging will only be useful in patients whose symptoms are of recent onset
-
Directory of Open Access Journals (Sweden)
Ciara Mahon
2015-09-01
Conclusion: This is the only study to date that has looked at the incidence of ischemic stroke following a confirmed LAA thrombus, LA thrombus or pre-thrombus state. This single centre study found low stroke rates over a six month follow-up period in patients with a confirmed LAA thrombus, LA thrombus or pre-thrombus state and optimization of OAC. Larger studies would be required to confirm these findings.
-
Categorization of aortic aneurysm thrombus morphology by magnetic resonance imaging
Energy Technology Data Exchange (ETDEWEB)
Motte, Louise de la, E-mail: louise.de.la.motte@rh.regionh.dk [Department of Vascular Surgery, Rigshospitalet and University of Copenhagen (Denmark); Pedersen, Mads Møller, E-mail: phd@medit.dk [Department of Radiology, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark); Thomsen, Carsten, E-mail: carsten.thomsen@rh.regionh.dk [Department of Radiology, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark); Vogt, Katja, E-mail: Vogt@dadlnet.dk [Department of Vascular Surgery, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark); Schroeder, Torben V., E-mail: Torben.Veith.schroeder@rh.regionh.dk [Department of Vascular Surgery, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark); Lonn, Lars, E-mail: lonn.lars@gmail.com [Department of Vascular Surgery and Department of Radiology, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen (Denmark)
2013-10-01
Background: Magnetic resonance imaging (MRI) has been proposed for qualitative categorization of intraluminal thrombus morphology. We aimed to correlate the qualitative MRI categorization previously described to quantitative measurements of signal intensity and to compare morphological characteristics of intraluminal thrombus specimens to the appearance on magnetic resonance imaging. Methods: Thirty-four patients undergoing open surgery for abdominal aortic aneurysm had a preoperative MRI obtained with a 1.5 T magnet. Qualitative categorization was performed (blinded and in consensus) and correlated to intraluminal thrombus to muscle signal-intensity ratios. Morphology of intraluminal thrombus specimens collected during surgery were compared to the magnetic resonance imaging categories and specimen weight was correlated to thrombus volume measured on preoperative computer tomography angiography. Results: Blinded MRI categorization resulted in agreement in 22 out of 34 intraluminal thrombi (Kappa value 0.3, p = 0.006). Medians (p = 0.004) and distribution (p = 0.002) of signal-intensity ratios varied significantly across the three MRI categories obtained by consensus. Heterogeneous and homogenous specimen appearance corresponded to similar appearances on MRI in 78% and 55% respectively, resulting in an overall Kappa = 0.4 (p = 0.04). Intraluminal thrombus volume and weight correlated well (r{sub s} 0.831, p < 0.001) with a mean difference of 60 g (95% CI 38–80 g), without proportional bias. Conclusion: Qualitative evaluation of intraluminal thrombus morphology based on MRI can be quantified by measuring signal-intensity ratios. Concurrently a fair agreement to blinded qualitative evaluation of thrombus specimens can be obtained. However, the evaluation is impaired by loss of a large proportion of thrombus during sampling.
-
Categorization of aortic aneurysm thrombus morphology by magnetic resonance imaging
International Nuclear Information System (INIS)
Motte, Louise de la; Pedersen, Mads Møller; Thomsen, Carsten; Vogt, Katja; Schroeder, Torben V.; Lonn, Lars
2013-01-01
Background: Magnetic resonance imaging (MRI) has been proposed for qualitative categorization of intraluminal thrombus morphology. We aimed to correlate the qualitative MRI categorization previously described to quantitative measurements of signal intensity and to compare morphological characteristics of intraluminal thrombus specimens to the appearance on magnetic resonance imaging. Methods: Thirty-four patients undergoing open surgery for abdominal aortic aneurysm had a preoperative MRI obtained with a 1.5 T magnet. Qualitative categorization was performed (blinded and in consensus) and correlated to intraluminal thrombus to muscle signal-intensity ratios. Morphology of intraluminal thrombus specimens collected during surgery were compared to the magnetic resonance imaging categories and specimen weight was correlated to thrombus volume measured on preoperative computer tomography angiography. Results: Blinded MRI categorization resulted in agreement in 22 out of 34 intraluminal thrombi (Kappa value 0.3, p = 0.006). Medians (p = 0.004) and distribution (p = 0.002) of signal-intensity ratios varied significantly across the three MRI categories obtained by consensus. Heterogeneous and homogenous specimen appearance corresponded to similar appearances on MRI in 78% and 55% respectively, resulting in an overall Kappa = 0.4 (p = 0.04). Intraluminal thrombus volume and weight correlated well (r s 0.831, p < 0.001) with a mean difference of 60 g (95% CI 38–80 g), without proportional bias. Conclusion: Qualitative evaluation of intraluminal thrombus morphology based on MRI can be quantified by measuring signal-intensity ratios. Concurrently a fair agreement to blinded qualitative evaluation of thrombus specimens can be obtained. However, the evaluation is impaired by loss of a large proportion of thrombus during sampling
-
Fortunato, Tiago M; Beltrami, Cristina; Emanueli, Costanza; De Bank, Paul A; Pula, Giordano
2016-05-04
Revascularisation is a key step for tissue regeneration and complete organ engineering. We describe the generation of human platelet lysate gel (hPLG), an extracellular matrix preparation from human platelets able to support the proliferation of endothelial colony forming cells (ECFCs) in 2D cultures and the formation of a complete microvascular network in vitro in 3D cultures. Existing extracellular matrix preparations require addition of high concentrations of recombinant growth factors and allow only limited formation of capillary-like structures. Additional advantages of our approach over existing extracellular matrices are the absence of any animal product in the composition hPLG and the possibility of obtaining hPLG from patients to generate homologous scaffolds for re-implantation. This discovery has the potential to accelerate the development of regenerative medicine applications based on implantation of microvascular networks expanded ex vivo or the generation of fully vascularised organs.
-
Purinergic control of inflammation and thrombosis: Role of P2X1 receptors
Directory of Open Access Journals (Sweden)
Cécile Oury
2015-01-01
Full Text Available Inflammation shifts the hemostatic mechanisms in favor of thrombosis. Upon tissue damage or infection, a sudden increase of extracellular ATP occurs, that might contribute to the crosstalk between inflammation and thrombosis. On platelets, P2X1 receptors act to amplify platelet activation and aggregation induced by other platelet agonists. These receptors critically contribute to thrombus stability in small arteries. Besides platelets, studies by our group indicate that these receptors are expressed by neutrophils. They promote neutrophil chemotaxis, both in vitro and in vivo. In a laser-induced injury mouse model of thrombosis, it appears that neutrophils are required to initiate thrombus formation and coagulation activation on inflamed arteriolar endothelia. In this model, by using P2X1−/− mice, we recently showed that P2X1 receptors, expressed on platelets and neutrophils, play a key role in thrombus growth and fibrin generation. Intriguingly, in a model of endotoxemia, P2X1−/− mice exhibited aggravated oxidative tissue damage, along with exacerbated thrombocytopenia and increased activation of coagulation, which translated into higher susceptibility to septic shock. Thus, besides its ability to recruit neutrophils and platelets on inflamed endothelia, the P2X1 receptor also contributes to limit the activation of circulating neutrophils under systemic inflammatory conditions. Taken together, these data suggest that P2X1 receptors are involved in the interplay between platelets, neutrophils and thrombosis. We propose that activation of these receptors by ATP on neutrophils and platelets represents a new mechanism that regulates thrombo-inflammation.
-
Sakota, Daisuke; Fujiwara, Tatsuki; Ohuchi, Katsuhiro; Kuwana, Katsuyuki; Yamazaki, Hiroyuki; Kosaka, Ryo; Nishida, Masahiro; Mizuno, Tomohiro; Arai, Hirokuni; Maruyama, Osamu
2018-01-01
We developed an optical thrombus sensor for a monopivot extracorporeal centrifugal blood pump. In this study, we investigated its quantitative performance for thrombus detection in acute animal experiments of left ventricular assist using the pump on pathogen-free pigs. Optical fibers were set in the driver unit of the pump. The incident light at the near-infrared wavelength of 810 nm was aimed at the pivot bearing, and the resulting scattered light was guided to the optical fibers. The detected signal was analyzed to obtain the thrombus formation level. As a result, real-time and quantitative monitoring of the thrombus surface area on the pivot bearing was achieved with an accuracy of 3.6 ± 2.3 mm 2 . In addition, the sensing method using the near-infrared light was not influenced by changes in the oxygen saturation and the hematocrit. It is expected that the developed sensor will be useful for optimal anticoagulation management for long-term extracorporeal circulation therapies.
-
Phytochemical Assay and Antiplatelet Activity of Fractions of Velvet Bean Seeds (Mucuna pruriens L.
Directory of Open Access Journals (Sweden)
VICTOR IMMANUEL
2010-06-01
Full Text Available Platelet aggregation is an important factor contributing to the formation of thrombus due to an uncontrolled blood clotting. An antiplatelet agent is a compound which decreases platelet aggregation and inhibits thrombus formation. The objectives of this study were to determine the class of compound employing phytochemical assay and to determine the in vitro antiplatelet activity of four fraction, namely hexane, ethyl acetate, butanol, and water fractions of velvet bean seeds (Mucuna pruriens L. using epinephrine (EPN as agonist of platelet aggregation. The antiplatelet activities were tested in human platelet rich plasma with hyperaggregation. To determine the activities, EPN was arranged at 4 level of concentrations (300, 150, 75, and 30 μM, and antiplatelet agents were at 500 µg/ml. The results indicated that ethyl acetate, butanol and water fraction contained high flavonoids and moderate phenols. The water, butanol and ethyl acetate fractions of velvet bean seeds exhibited potential inhibition of EPN-induced platelet aggregation at all concentrations. The strongest antiplatelet agent was water fraction and had the same antiplatelet activity as aspirin at level 150, 75, and 30 μM of EPN. Butanol fraction had the same antiplatelet activity as aspirin at the lowest EPN (30 μM.
-
Phytochemicalassay and Antiplatelet Activity of Fractions of Velvet Bean Seeds (Mucuna pruriens L.
Directory of Open Access Journals (Sweden)
WAHYU WIDOWATI
2010-06-01
Full Text Available Platelet aggregation is an important factor contributing to the formation of thrombus due to an uncontrolled blood clotting. An antiplatelet agent is a compound which decreases platelet aggregation and inhibits thrombus formation. The objectives of this study were to determine the class of compound employing phytochemical assay and to determine the in vitro antiplatelet activity of four fraction, namely hexane, ethyl acetate, butanol, and water fractions of velvet bean seeds (Mucuna pruriens L. using epinephrine (EPN as agonist of platelet aggregation. The antiplatelet activities were tested in human platelet rich plasma with hyperaggregation. To determine the activities, EPN was arranged at 4 level of concentrations (300, 150, 75, and 30 ì M, and antiplatelet agents were at 500 µg/ml. The results indicated that ethyl acetate, butanol and water fraction contained high flavonoids and moderate phenols. The water, butanol and ethyl acetate fractions of velvet bean seeds exhibited potential inhibition of EPN-induced platelet aggregation at all concentrations. The strongest antiplatelet agent was water fraction and had the same antiplatelet activity as aspirin at level 150, 75, and 30 ì M of EPN. Butanol fraction had the same antiplatelet activity as aspirin at the lowest EPN (30 ì M.
-
Energy Technology Data Exchange (ETDEWEB)
Staab, W.; Zwaka, P.A.; Sohns, J.M.; Schwarz, A.; Lotz, J. [University Medical Center Goettingen Univ. (Germany). Inst. for Diagnostic and Interventional Radiology; Sohns, C.; Vollmann, D.; Zabel, M.; Hasenfuss, G. [Goettingen Univ. (Germany). Dept. of Cardiology and Pneumology; Schneider, S. [Goettingen Univ. (Germany). Dept. of Medical Statistics
2014-11-15
Evaluation of a new cardiac MDCT protocol using a split-bolus contrast injection protocol and single MDCT scan for reliable diagnosis of LA/LAA thrombi in comparison to TEE, optimizing radiation exposure and use of contrast agent. A total of 182 consecutive patients with drug refractory AF scheduled for PVI (62.6% male, mean age: 64.1 ± 10.2 years) underwent routine diagnostic work including TEE and cardiac MDCT for the evaluation of LA/LAA anatomy and thrombus formation between November 2010 and March 2012. Contrast media injection was split into a pre-bolus of 30 ml and main bolus of 70 ml iodinated contrast agent separated by a short time delay. In this study, split-bolus cardiac MDCT identified 14 of 182 patients with filling defects of the LA/LAA. In all of these 14 patients, abnormalities were found in TEE. All 5 of the 14 patients with thrombus formation in cardiac MDCT were confirmed by TEE. MDCT was 100% accurate for thrombus, with strong but not perfect overall results for SEC equivalent on MDCT.
-
Inhibitory Effect of Flavonolignans on the P2Y12 Pathway in Blood Platelets.
Bijak, Michal; Szelenberger, Rafal; Dziedzic, Angela; Saluk-Bijak, Joanna
2018-02-10
Adenosine diphosphate (ADP) is the major platelet agonist, which is important in the shape changes, stability, and growth of the thrombus. Platelet activation by ADP is associated with the G protein-coupled receptors P2Y1 and P2Y12. The pharmacologic blockade of the P2Y12 receptor significantly reduces the risk of peripheral artery disease, myocardial infarction, ischemic stroke, and vascular death. Recent studies demonstrated the inhibition of ADP-induced blood platelet activation by three major compounds of the flavonolignans group: silybin, silychristin, and silydianin. For this reason, the aim of the current work was to verify the effects of silybin, silychristin, and silydianin on ADP-induced physiological platelets responses, as well as mechanisms of P2Y12-dependent intracellular signal transduction. We evaluated the effect of tested flavonolignans on ADP-induced blood platelets' aggregation in platelet-rich plasma (PRP) (using light transmission aggregometry), adhesion to fibrinogen (using the static method), and the secretion of PF-4 (using the ELISA method). Additionally, using the double labeled flow cytometry method, we estimated platelet vasodilator-stimulated phosphoprotein (VASP) phosphorylation. We demonstrated a dose-dependent reduction of blood platelets' ability to perform ADP-induced aggregation, adhere to fibrinogen, and secrete PF-4 in samples treated with flavonolignans. Additionally, we observed that all of the tested flavonolignans were able to increase VASP phosphorylation in blood platelets samples, which is correlated with P2Y12 receptor inhibition. All of these analyses show that silychristin and silybin have the strongest inhibitory effect on blood platelet activation by ADP, while silydianin also inhibits the ADP pathway, but to a lesser extent. The results obtained in this study clearly demonstrate that silybin, silychristin, and silydianin have inhibitory properties against the P2Y12 receptor and block ADP-induced blood platelet
-
Directory of Open Access Journals (Sweden)
Xu Zhiliang
2010-01-01
Full Text Available We study the problem of segmenting, reconstructing, and analyzing the structure growth of thrombi (clots in blood vessels in vivo based on 2-photon microscopic image data. First, we develop an algorithm for segmenting clots in 3D microscopic images based on density-based clustering and methods for dealing with imaging artifacts. Next, we apply the union-of-balls (or alpha-shape algorithm to reconstruct the boundary of clots in 3D. Finally, we perform experimental studies and analysis on the reconstructed clots and obtain quantitative data of thrombus growth and structures. We conduct experiments on laser-induced injuries in vessels of two types of mice (the wild type and the type with low levels of coagulation factor VII and analyze and compare the developing clot structures based on their reconstructed clots from image data. The results we obtain are of biomedical significance. Our quantitative analysis of the clot composition leads to better understanding of the thrombus development, and is valuable to the modeling and verification of computational simulation of thrombogenesis.
-
An unexpected complication of acute pancreatitis: Intra-cardiac thrombus.
Keskin, Muhammed; Gümüşdağ, Ayça; Börklü, Edibe Betül; Dayı, Şennur Ünal; Avcı, İlhan İlker; Güvenç, Tolga Sinan; Güngör, Barış; Karabay, Can Yücel; Kozan, Ömer
2017-05-01
Left atrial thrombus after acute pancreatitis (AP) is a rare clinical statement. Because of induction of systemic prothrombotic process by AP; some patients with underlying risk factors may develop an intra-cardiac thrombus. We present a 53years-old-woman with moderate mitral stenosis and atrial fibrillation. However the patient was under warfarin treatment, she developed a big left atrial big thrombus which was originated from left atrial appendage after she was suffered from AP. Copyright © 2016 Elsevier Inc. All rights reserved.
-
von Brühl, Marie-Luise; Stark, Konstantin; Steinhart, Alexander; Chandraratne, Sue; Konrad, Ildiko; Lorenz, Michael; Khandoga, Alexander; Tirniceriu, Anca; Coletti, Raffaele; Köllnberger, Maria; Byrne, Robert A.; Laitinen, Iina; Walch, Axel; Brill, Alexander; Pfeiler, Susanne; Manukyan, Davit; Braun, Siegmund; Lange, Philipp; Riegger, Julia; Ware, Jerry; Eckart, Annekathrin; Haidari, Selgai; Rudelius, Martina; Schulz, Christian; Echtler, Katrin; Brinkmann, Volker; Schwaiger, Markus; Preissner, Klaus T.; Wagner, Denisa D.; Mackman, Nigel; Engelmann, Bernd
2012-01-01
Deep vein thrombosis (DVT) is a major cause of cardiovascular death. The sequence of events that promote DVT remains obscure, largely as a result of the lack of an appropriate rodent model. We describe a novel mouse model of DVT which reproduces a frequent trigger and resembles the time course, histological features, and clinical presentation of DVT in humans. We demonstrate by intravital two-photon and epifluorescence microscopy that blood monocytes and neutrophils crawling along and adhering to the venous endothelium provide the initiating stimulus for DVT development. Using conditional mutants and bone marrow chimeras, we show that intravascular activation of the extrinsic pathway of coagulation via tissue factor (TF) derived from myeloid leukocytes causes the extensive intraluminal fibrin formation characteristic of DVT. We demonstrate that thrombus-resident neutrophils are indispensable for subsequent DVT propagation by binding factor XII (FXII) and by supporting its activation through the release of neutrophil extracellular traps (NETs). Correspondingly, neutropenia, genetic ablation of FXII, or disintegration of NETs each confers protection against DVT amplification. Platelets associate with innate immune cells via glycoprotein Ibα and contribute to DVT progression by promoting leukocyte recruitment and stimulating neutrophil-dependent coagulation. Hence, we identified a cross talk between monocytes, neutrophils, and platelets responsible for the initiation and amplification of DVT and for inducing its unique clinical features. PMID:22451716
-
Study of 99Tcm-annexin V distribution in inferior vena cava thrombus models of rabbits
International Nuclear Information System (INIS)
Wu Dayong; Zhang Wenyan; Bian Yanzhu; Hu Yujing
2013-01-01
To study 99 Tc m -Annexin V distribution in inferior vena cava thrombus models of rabbits and uptake of 99 Tc m -Annexin V in fresh and old venous thrombus. Rabbits (n=15) were randomly grouped into 3 groups (the fresh thrombus group, old thrombus group, and control group). The rabbits of two thrombus groups developed inferior vena cava thrombus models by operations. The control group received sham operation. The fresh thrombus group and control group rabbits were injected 99 Tc m -Annexin V after operating 1 d; the old thrombus group 14 d. After 1 h all rabbits were killed by injecting overdose pentobarbital sodium. The thrombus (or the inferior vena cava about 3 cm below inferior pole of right kidney level in the control group rabbits), blood, thrombus area inferior vena cava, head lateral inferior vena cava (except the control group), thigh muscle, stomach, myocardium, pulmonary, liver, kidney, spleen, bone and small intestine were obtained from all group rabbits. The ex tissue and blood were weighed and measured by a Well-type detector. The percentage of the injected dose per gram of ex tissue (or blood) was calculated by the above data. The thrombus to blood, thrombus area inferior vena cava, head lateral inferior vena cava and thigh muscle ratios were calculated by percentage of the injected dose per gram of ex tissue (or blood). The test was used to compare the fresh thrombus group and old thrombus group by SPSS 17.0. The percentage of' the injected dose per gram of thrombi (0.01894± 0.002 16% ID/g) in the fresh thrombus group was higher than the old thrombus group (0.00473±0.001 28% ID/g), P<0.05. The thrombus to blood, thrombus area inferior vena cava, head lateral inferior vena cava and muscle ratios (3.42±1.06, 26.32±13.60, 31.23 ±16.00, 111.62±52.23) in the fresh thrombus group were higher than the old thrombus group (0.98±0.09, 5.12±2.01, 6.25±2.38, 21.82±5.93), P<0.05 for all. All the thrombi of the fresh thrombus group were confirmed
-
Directory of Open Access Journals (Sweden)
Nathan J. Sniadecki
2011-12-01
Full Text Available Coagulation involves a complex set of events that are important in maintaining hemostasis. Biochemical interactions are classically known to regulate the hemostatic process, but recent evidence has revealed that mechanical interactions between platelets and their surroundings can also play a substantial role. Investigations into platelet mechanobiology have been challenging however, due to the small dimensions of platelets and their glycoprotein receptors. Platelet researchers have recently turned to microfabricated devices to control these physical, nanometer-scale interactions with a higher degree of precision. These approaches have enabled exciting, new insights into the molecular and biomechanical factors that affect platelets in clot formation. In this review, we highlight the new tools used to understand platelet mechanobiology and the roles of adhesion, shear flow, and retraction forces in clot formation.
-
Absence of micronucleus formation in CHO-K1 cells cultivated in platelet lysate enriched medium.
Bernardi, Martina; Adami, Valentina; Albiero, Elena; Madeo, Domenico; Rodeghiero, Francesco; Astori, Giuseppe
2014-03-01
Human platelet lysate (PL) represents an effective substitute of fetal bovine serum (FBS) for mesenchymal stromal cell (MSC) cultivation. Compared to FBS, PL favors MSC proliferation significantly shortening the population doubling time and avoiding the risks related to the use of animal derivatives. Growth factors contained in the platelets are released upon platelet disruption following freezing/thawing cycles or as we have recently described by using ultrasound. We have investigated whether the increased cell proliferation achieved by using PL could induce mitotic stress and whether the potential formation of free radicals during PL production by ultrasound could cause chromosomal instability in mammalian cells. We have applied an image analysis assisted high content screening (HCS) in vitro micronucleus assay in the Chinese Hamster Ovarian K1 (CHO-K1) rodent mammalian cell line. PL was produced by sonication; for the micronucleus assay, CHO-K1 cells were exposed to increasing concentrations of PL. Cytokinesis was blocked by cytochalasin B, nuclei were stained with bisbenzimide and images were acquired and analyzed automatically using an HCS system, both with a 20× and a 10× objective. Our results suggest that growth stimulus induced by the use of PL did not significantly increase micronucleus formation in CHO-K1 cells compared to negative control. Micronucleus testing in conjunction with HCS could represent a valid tool to evaluate the safety of ancillary materials used in the production of cell-based medicinal products. Copyright © 2013 Elsevier GmbH. All rights reserved.
-
Platelet thromboxane B2-formation in end-stage kidney disease and after kidney transplantation
International Nuclear Information System (INIS)
Stefanovic, V.; Lecic, N.
1986-01-01
The aim of this work was to analyse TxB 2 formation by platelets in endstage kidney disease patients and in kidney graft recipients. Four groups of patients were studied: 12 preterminal chronic renal failure patients, 42 patients on maintenance hemodialysis, 8 patients on CAPD and 11 grafted patients. TxB 2 production by platelets was determined in serum following spontaneous blood clotting for 1/2 h at 37 0 C. Hemodialysis patients generated 80.7 ± 9.6 ng/ml (mean ± S.E.M.) of TxB 2 which was significantly (p 2 formation in hemodialysis patients had no relationship with the residual kidney function. Patients on CAPD produced 65.0 ± 12.7 ng/ml of TxB 2 . Very low TxB 2 generation was obtained also in preterminal chronic renal failure patients (57.0 ± 11.8 ng/ml). Kidney graft recipients had a mean TxB 2 production of 81.6 ± 24.2 ng/ml with a range from 12.5-200 ng/ml. Very low TxB 2 was formed in grafted patients with renal failure. (orig.) [de
-
Flavanols and Platelet Reactivity
Directory of Open Access Journals (Sweden)
Debra A. Pearson
2005-01-01
Full Text Available Platelet activity and platelet-endothelial cell interactions are important in the acute development of thrombosis, as well as in the pathogenesis of cardiovascular disease. An increasing number of foods have been reported to have platelet-inhibitory actions, and research with a number of flavanol-rich foods, including, grape juice, cocoa and chocolate, suggests that these foods may provide some protection against thrombosis. In the present report, we review a series of in vivo studies on the effects of flavanol-rich cocoa and chocolate on platelet activation and platelet-dependent primary hemostasis. Consumption of flavanol-rich cocoa inhibited several measures of platelet activity including, epinephrine- and ADP-induced glycoprotein (GP IIb/IIIa and P-Selectin expression, platelet microparticle formation, and epinephrine-collagen and ADP-collagen induced primary hemostasis. The epinephrine-induced inhibitory effects on GP IIb/IIIa and primary hemostasis were similar to, though less robust than those associated with the use of low dose (81 mg aspirin. These data, coupled with information from other studies, support the concept that flavanols present in cocoa and chocolate can modulate platelet function through a multitude of pathways.
-
Characterization of an experimental venous thrombus model with MRI, phlebography and histology
International Nuclear Information System (INIS)
Schmitz, S.A.; Schiffler, S.; Gust, R.; Winterhalter, S.; Wolf, K.J.; Coupland, S.E.
2005-01-01
Introduction: Several magnetic resonance (MR) techniques designed to demonstrate the characteristic signal intensity of blood degeneration products of thrombi have been suggested, but the effect of thrombus organization on the MR display, in particular with regard to its temporal evolution, remains to be determined. It is the purpose of this study to develop a stagnation thrombus model in rabbits and to characterize thrombus at different ages with two (MR) imaging techniques, phlebography and histology. Materials and Methods: Venous stagnation thrombi were induced in the external jugular veins of rabbits using a minimally invasive radiological technique to produce artificial embolic vascular occlusion and hypercoagulability. Twenty-five animals were divided into 5 groups of 5 animals, and each group underwent 1.5 T MR imaging at 1, 3, 5, 7 and 9 days after thrombus induction using a T1-weighted magnetization-prepared rapid gradient-echo sequence (MP-RAGE: TR 10.4 msec, TE 4.0 msec, FA 15 ) and a T2-weighted fast low-angle shot sequence (FLASH: TR 54 msec, TE 18 msec, FA15 ). The thrombus length was measured on the T1-weighted images. Thrombus conspicuity, signal intensity, and heterogeneity on T2* weighted images were described using visual scales. Radiographic venography and histology served as reference methods. Results: Thrombi were successfully induced in all animals. The overall thrombus length decreased from 43±9 (day 1 after induction) to 23±4 mm (day 9). On 3D-reconstructions of the T1-weighted images, the visible portion of the true thrombus length relative to the overall thrombus length was 0.16±0.3 (day 1), 0.24±0.3 (day 3),0.38±0.5 (day 5), 0.06±0.1 (day 7) and 0.00 (day 9). Sixteen of 25 thrombi were detectable with the T2*-weighted technique. The overall thrombus signal intensity decreased with the age of the thrombus from day 1 to day 9. The histological evaluation showed that the rabbit thrombi closely resemble human thrombi morphologically
-
Łukasiewicz, Adam; Garkowski, Adam; Rutka, Katarzyna; Janica, Jacek; Łebkowska, Urszula
2016-09-01
It is hypothesized that the degree of vascularization of the thrombus may have a significant impact on the rupture of aortic aneurysms. The presence of neovascularization of the vessel wall and mural thrombus has been confirmed only in histopathological studies. However, no non-invasive imaging technique of qualitative assessment of thrombus and neovascularization has been implemented so far. Contrast-enhanced ultrasound (CEUS) has been proposed as a feasible and minimally invasive technique for in vivo visualization of neovascularization in the evaluation of tumors and atherosclerotic plaques. The aim of this study was the evaluation of mural thrombus and AAAs wall with CEUS. CEUS was performed in a group of seventeen patients with AAAs. The mural thrombus enhancement was recognized in 12 cases, yet no significant correlation between the degree of contrast enhancement and AAAs diameter, thrombus width, and thrombus echogenicity was found. We observed a rise in AAAs thrombus heterogeneity with the increase in the aneurysm diameter (r = 0.62, p = 0.017). In conclusion CEUS can visualize small channels within AAAs thrombus, which could be a result of an ongoing angiogenesis. There is a need for further research to find out whether the degree of vascularization of the thrombus may have a significant impact on the rupture of aneurysms.
-
Left atrial thrombus following bilobectomy: a case report
Directory of Open Access Journals (Sweden)
Kaya Ugur
2010-02-01
Full Text Available Abstract Introduction Left atrial free floating ball thrombus is a relatively rare event, especially without mitral valve disease. Case presentation A 61-year-old Turkish man was admitted to our hospital with a thrombus mass in his left atrium. Five months earlier, he had undergone right bilobectomy and superior bronchoplasty due to squamous cell carcinoma in the lung. The patient had no evidence of cardiac disease except atrial fibrillation and there were no defined embolizations. The thrombus mass was surgically removed. The patient was discharged from hospital on the sixth postoperative day. Conclusion Surgery with cardiopulmonary bypass is a safe method for treatment. The patient should be medicated with warfarin, especially in the presence of atrial fibrillation.
-
Kowalska, M Anna; Zhao, Guohua; Zhai, Li; David, George; Marcus, Stephen; Krishnaswamy, Sriram; Poncz, Mortimer
2014-01-01
Histones are detrimental in late sepsis. Both activated protein C (aPC) and heparin can reverse their effect. Here, we investigated whether histones can modulate aPC generation in a manner similar to another positively charged molecule, platelet factor 4, and how heparinoids (unfractionated heparin or oxygen-desulfated unfractionated heparin with marked decrease anticoagulant activity) may modulate this effect. We measured in vitro and in vivo effects of histones, platelet factor 4, and heparinoids on aPC formation, activated partial thromboplastin time, and murine survival. In vitro, histones and platelet factor 4 both affect thrombin/thrombomodulin aPC generation following a bell-shaped curve, with a peak of >5-fold enhancement. Heparinoids shift these curves rightward. Murine aPC generation studies after infusions of histones, platelet factor 4, and heparinoids supported the in vitro data. Importantly, although unfractionated heparin and 2-O, 3-O desulfated heparin both reversed the lethality of high-dose histone infusions, only mice treated with 2-O, 3-O desulfated heparin demonstrated corrected activated partial thromboplastin times and had significant levels of aPC. Our data provide a new contextual model of how histones affect aPC generation, and how heparinoid therapy may be beneficial in sepsis. These studies provide new insights into the complex interactions controlling aPC formation and suggest a novel therapeutic interventional strategy.
-
A Left Main Coronary Artery Thrombus Presenting as a Non St Elevation MI.
Ezema, U; Daberkow, D; Delord, T; Guidry, L; Sells, N R
2017-01-01
Left main coronary artery (LMCA); thrombus with an acute myocardial infarction identified with coronary angiography is a clinically rare condition with an extremely high mortality rate. We present a case of LMCA thrombus that presented as a non-ST elevation myocardial infarction (NSTEMI);. A 45-year-old woman with a history of tobacco use and hyperlipidemia presented with a complaint of 10/10 "hard pain" across her chest radiating to her left shoulder and breast which woke her from sleep. The pain was constant and severe, with no alleviation with rest. She had not experienced anything like this before. Workup revealed an upward trending troponin (1.98.989.79);, and an EKG with some tachycardia but no ST elevation or T wave changes. Her CBC, CMP and coagulation studies were unremarkable. A toxicology screen was positive for opiates and benzodiazepines, medications she was on for pain and anxiety respectively. ACS protocol was started with DAPT, LMWH, Statin, ACEi, and Beta-blocker. An angiogram revealed a large thrombus in the LM coronary artery extending into the aorta with concomitant 99 percent stenosis of distal LAD. 2D Echo w/ bubble contrast was significant for PFO, akinetic apical inferior and anterior wall. The mid antero-septum and apical lateral wall were hypokinetic. Interventional Cardiology and CTS recommended conservative management with medical optimization (Continue DAPT, heparin);, watchful waiting for the thrombus to resorb. Left main coronary artery thrombosis (LMCAT); identified during coronary angiography is a rare and challenging condition. It is a life threatening condition with an approximate incidence rate of 0.8 percent . It is thought to be secondary to plaque rupture with subsequent thrombus formation that is associated with persistent hypercoagulable state, cocaine induced plaque rupture or coronary vasospasm, post-partum state and embolization of intra-cardiac masses. The patient presentation can vary from sudden cardiac death to
-
Matrix Metalloproteinase 9 (MMP-9 Regulates Vein Wall Biomechanics in Murine Thrombus Resolution.
Directory of Open Access Journals (Sweden)
Khanh P Nguyen
Full Text Available Deep venous thrombosis is a common vascular problem with long-term complications including post-thrombotic syndrome. Post-thrombotic syndrome consists of leg pain, swelling and ulceration that is related to incomplete or maladaptive resolution of the venous thrombus as well as loss of compliance of the vein wall. We examine the role of metalloproteinase-9 (MMP-9, a gene important in extracellular remodeling in other vascular diseases, in mediating thrombus resolution and biomechanical changes of the vein wall.The effects of targeted deletion of MMP-9 were studied in an in vivo murine model of thrombus resolution using the FVB strain of mice. MMP-9 expression and activity significantly increased on day 3 after DVT. The lack of MMP-9 impaired thrombus resolution by 27% and this phenotype was rescued by the transplantation of wildtype bone marrow cells. Using novel biomechanical techniques, we demonstrated that the lack of MMP-9 significantly decreased thrombus-induced loss of vein wall compliance. Biomechanical analysis of the contribution of individual structural components showed that MMP-9 affected the elasticity of the extracellular matrix and collagen-elastin fibers. Biochemical and histological analyses correlated with these biomechanical effects as thrombi of mice lacking MMP-9 had significantly fewer macrophages and collagen as compared to those of wildtype mice.MMP-9 mediates thrombus-induced loss of vein wall compliance by increasing stiffness of the extracellular matrix and collagen-elastin fibers during thrombus resolution. MMP-9 also mediates macrophage and collagen content of the resolving thrombus and bone-marrow derived MMP-9 plays a role in resolution of thrombus mass. These disparate effects of MMP-9 on various aspects of thrombus illustrate the complexity of individual protease function on biomechanical and morphometric aspects of thrombus resolution.
-
Matrix Metalloproteinase 9 (MMP-9) Regulates Vein Wall Biomechanics in Murine Thrombus Resolution
Nguyen, Khanh P.; McGilvray, Kirk C.; Puttlitz, Christian M.; Mukhopadhyay, Subhradip; Chabasse, Christine; Sarkar, Rajabrata
2015-01-01
Objective Deep venous thrombosis is a common vascular problem with long-term complications including post-thrombotic syndrome. Post-thrombotic syndrome consists of leg pain, swelling and ulceration that is related to incomplete or maladaptive resolution of the venous thrombus as well as loss of compliance of the vein wall. We examine the role of metalloproteinase-9 (MMP-9), a gene important in extracellular remodeling in other vascular diseases, in mediating thrombus resolution and biomechanical changes of the vein wall. Methods and Results The effects of targeted deletion of MMP-9 were studied in an in vivo murine model of thrombus resolution using the FVB strain of mice. MMP-9 expression and activity significantly increased on day 3 after DVT. The lack of MMP-9 impaired thrombus resolution by 27% and this phenotype was rescued by the transplantation of wildtype bone marrow cells. Using novel biomechanical techniques, we demonstrated that the lack of MMP-9 significantly decreased thrombus-induced loss of vein wall compliance. Biomechanical analysis of the contribution of individual structural components showed that MMP-9 affected the elasticity of the extracellular matrix and collagen-elastin fibers. Biochemical and histological analyses correlated with these biomechanical effects as thrombi of mice lacking MMP-9 had significantly fewer macrophages and collagen as compared to those of wildtype mice. Conclusions MMP-9 mediates thrombus-induced loss of vein wall compliance by increasing stiffness of the extracellular matrix and collagen-elastin fibers during thrombus resolution. MMP-9 also mediates macrophage and collagen content of the resolving thrombus and bone-marrow derived MMP-9 plays a role in resolution of thrombus mass. These disparate effects of MMP-9 on various aspects of thrombus illustrate the complexity of individual protease function on biomechanical and morphometric aspects of thrombus resolution. PMID:26406902
-
Alternatives to allogeneic platelet transfusion.
Desborough, Michael J R; Smethurst, Peter A; Estcourt, Lise J; Stanworth, Simon J
2016-11-01
Allogeneic platelet transfusions are widely used for the prevention and treatment of bleeding in thrombocytopenia. Recent evidence suggests platelet transfusions have limited efficacy and are associated with uncertain immunomodulatory risks and concerns about viral or bacterial transmission. Alternatives to transfusion are a well-recognised tenet of Patient Blood Management, but there has been less focus on different strategies to reduce bleeding risk by comparison to platelet transfusion. Direct alternatives to platelet transfusion include agents to stimulate endogenous platelet production (thrombopoietin mimetics), optimising platelet adhesion to endothelium by treating anaemia or increasing von Willebrand factor levels (desmopressin), increasing formation of cross-linked fibrinogen (activated recombinant factor VII, fibrinogen concentrate or recombinant factor XIII), decreasing fibrinolysis (tranexamic acid or epsilon aminocaproic acid) or using artificial or modified platelets (cryopreserved platelets, lyophilised platelets, haemostatic particles, liposomes, engineered nanoparticles or infusible platelet membranes). The evidence base to support the use of these alternatives is variable, but an area of active research. Much of the current randomised controlled trial focus is on evaluation of the use of thrombopoietin mimetics and anti-fibrinolytics. It is also recognised that one alternative strategy to platelet transfusion is choosing not to transfuse at all. © 2016 John Wiley & Sons Ltd.
-
Metastatic Adenocarcinoma Presenting as Extensive Cavoatrial Tumor Thrombus
International Nuclear Information System (INIS)
Johari, Bushra; Abdul Aziz, Yang Faridah; Krishnasamy, Sivakumar; Looi, Lai Meng; Hashim, Shahrul Amry; Raja Mokhtar, Raja Amin
2015-01-01
The presence of tumor thrombus in the right atrium is frequently the result of direct intraluminal extension of infra-diaphragmatic malignancy into the inferior vena cava (IVC) or supradiaphragmatic carcinoma into the superior vena cava (SVC). Right atrial tumor thrombus with extension into both SVC and IVC has not been reported in the literature. We present a patient who presented with symptoms of right atrial and SVC obstruction. Imaging revealed presence of a thrombus in the right atrium, extending to the SVC and IVC, with the additional findings of a left adrenal mass and multiple liver lesions. The histopathological examination of the right atrial mass revealed metastatic adenocarcinoma cells. The patient was given a presumptive diagnosis of metastatic adenocarcinoma, most likely adrenal in origin, with multiple hepatic lesions suspicious for metastasis. The clinical outcome of the patient was not favorable; the patient succumbed before the adrenal mass could be confirmed to be the primary tumor. This case highlights that in patients manifesting with extensive cavoatrial thrombus as, the existence of primary carcinoma should be considered especially in the adrenal cortex or in the lung
-
Suntravat, Montamas; Jia, Ying; Lucena, Sara E.; Sánchez, Elda E.; Pérez, John C.
2013-01-01
A 5′ truncated snake venom metalloproteinase was identified from a cDNA library constructed from venom glands of an eastern diamondback rattlesnake (Crotalus adamanteus). The 5′-rapid amplification of cDNA ends (RACE) was used to obtain the 1865 bp full-length cDNA sequence of a snake venom metalloproteinase (CamVMPII). CamVMPII encodes an open reading frame of 488 amino acids, which includes a signal peptide, a pro-domain, a metalloproteinase domain, a spacer, and an RGD-disintegrin domain. The predicted amino acid sequence of CamVMPII showed a 91%, 90%, 83%, and 82% sequence homology to the P-II class enzymes of C. adamanteus metalloproteinase 2, C. atrox CaVMP-II, Gloydius halys agkistin, and Protobothrops jerdonii jerdonitin, respectively. Disintegrins are potent inhibitors of both platelet aggregation and integrin-dependent cell adhesion. Therefore, the disintegrin domain (Cam-dis) of CamVMPII was amplified by PCR, cloned into a pET-43.1a vector, and expressed in Escherichia coli BL21. Affinity purified recombinantly modified Cam-dis (r-Cam-dis) with a yield of 8.5 mg/L culture medium was cleaved from the fusion tags by enterokinase cleavage. r-Cam-dis was further purified by two-step chromatography consisting of HiTrap™ Benzamidine FF column, followed by Talon Metal affinity column with a final yield of 1 mg/L culture. r-Cam-dis was able to inhibit all three processes of platelet thrombus formation including platelet adhesion with an estimated IC50 of 1 nM, collagen- and ADP-induced platelet aggregation with the estimated IC50s of 18 and 6 nM, respectively, and platelet function on clot retraction. It is a potent anti-platelet inhibitor, which should be further investigated for drug discovery to treat stroke patients or patients with thrombotic disorders. PMID:23313448
-
Subpopulations in purified platelets adhering on glass.
Donati, Alessia; Gupta, Swati; Reviakine, Ilya
2016-06-22
Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process.
-
The life cycle of platelet granules.
Sharda, Anish; Flaumenhaft, Robert
2018-01-01
Platelet granules are unique among secretory vesicles in both their content and their life cycle. Platelets contain three major granule types-dense granules, α-granules, and lysosomes-although other granule types have been reported. Dense granules and α-granules are the most well-studied and the most physiologically important. Platelet granules are formed in large, multilobulated cells, termed megakaryocytes, prior to transport into platelets. The biogenesis of dense granules and α-granules involves common but also distinct pathways. Both are formed from the trans -Golgi network and early endosomes and mature in multivesicular bodies, but the formation of dense granules requires trafficking machinery different from that of α-granules. Following formation in the megakaryocyte body, both granule types are transported through and mature in long proplatelet extensions prior to the release of nascent platelets into the bloodstream. Granules remain stored in circulating platelets until platelet activation triggers the exocytosis of their contents. Soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, located on both the granules and target membranes, provide the mechanical energy that enables membrane fusion during both granulogenesis and exocytosis. The function of these core fusion engines is controlled by SNARE regulators, which direct the site, timing, and extent to which these SNAREs interact and consequently the resulting membrane fusion. In this review, we assess new developments in the study of platelet granules, from their generation to their exocytosis.
-
Alves, Heitor C; Treurniet, Kilian M; Dutra, Bruna G; Jansen, Ivo G H; Boers, Anna M M; Santos, Emilie M M; Berkhemer, Olvert A; Dippel, Diederik W J; van der Lugt, Aad; van Zwam, Wim H; van Oostenbrugge, Robert J; Lingsma, Hester F; Roos, Yvo B W E M; Yoo, Albert J; Marquering, Henk A; Majoie, Charles B L M
2018-02-01
Thrombus characteristics and collateral score are associated with functional outcome in patients with acute ischemic stroke. It has been suggested that they affect each other. The aim of this study is to evaluate the association between clot burden score, thrombus perviousness, and collateral score and to determine whether collateral score influences the association of thrombus characteristics with functional outcome. Patients with baseline thin-slice noncontrast computed tomography and computed tomographic angiography images from the MR CLEAN trial (Multicenter Randomized Clinical Trial of Endovascular Treatment of Acute Ischemic Stroke in the Netherlands) were included (n=195). Collateral score and clot burden scores were determined on baseline computed tomographic angiography. Thrombus attenuation increase was determined by comparing thrombus density on noncontrast computed tomography and computed tomographic angiography using a semiautomated method. The association of collateral score with clot burden score and thrombus attenuation increase was evaluated with linear regression. Mediation and effect modification analyses were used to assess the influence of collateral score on the association of clot burden score and thrombus attenuation increase with functional outcome. A higher clot burden score (B=0.063; 95% confidence interval, 0.008-0.118) and a higher thrombus attenuation increase (B=0.014; 95% confidence interval, 0.003-0.026) were associated with higher collateral score. Collateral score mediated the association of clot burden score with functional outcome. The association between thrombus attenuation increase and functional outcome was modified by the collateral score, and this association was stronger in patients with moderate and good collaterals. Patients with lower thrombus burden and higher thrombus perviousness scores had higher collateral score. The positive effect of thrombus perviousness on clinical outcome was only present in patients with
-
International Nuclear Information System (INIS)
Kalen, Anders; Wahlstroem, Ola; Linder, Cecilia Halling; Magnusson, Per
2008-01-01
Platelet derivates and platelet rich plasma have been used to stimulate bone formation and wound healing because of the rich content of potent growth factors. However, not all reports have been conclusive since some have not been able to demonstrate a positive effect. We investigated the interindividual variation of bone morphogenetic proteins (BMPs) in platelets from healthy donors, and the pH-dependent effect on the release of BMPs in preparations of lysed platelets in buffer (LPB). Platelet concentrates from 31 healthy donors were prepared in pH 4.3 and pH 7.4 buffers and investigated with respect to BMP-2, -4, -6, and -7. BMP-2 and BMP-4 were significantly more common in acidic LPBs in comparison with neutral preparations. We also observed a considerable variation among platelet donors with respect to the release of BMPs at pH 4.3 and 7.4. In conclusion, a considerable variation was found among platelet donors, which may be of importance considering the ambiguous results previously reported on osteoblast proliferation and differentiation
-
The role of platelets during reproduction.
Isermann, Berend; Nawroth, Peter P
2006-01-01
The availability of mice with defined defects within the hemostatic system enabled researchers to identify a role the coagulation system for embryonic and placental development. However, the role of platelets during development has only recently been experimentally addressed, giving some insight into potential functions of platelets during development. Thus, a quantitative embryonic platelet defect (severe thrombopenia secondary to NF-E2 deficiency) is associated with an embryonic growth retardation and reduced vascularisation of the placenta. Maternal platelet deficiency is associated with placental hemorrhage, which, however, does not impair embryonic or maternal survival. In vitro studies established that platelets or platelet conditioned medium regulate the invasive properties of human extravillous trophoblast cells and induce a phenotypical switch of trophoblast cells. These data imply that platelets are of relevance during placentation. Conversely, platelets and the formation of platelet-fibrin aggregates are dispensable for the development of the embryo proper, establishing that the lethal phenotypes observed in some embryo slacking coagulation regulators does not result from an inability to form platelet-fibrin aggregates, but likely reflects altered protease dependent signaling during vascular development.
-
Intracardiac thrombus in Behçet's disease: Two case reports
Directory of Open Access Journals (Sweden)
Brahem Radhia
2005-07-01
Full Text Available Abstract Intracardiac thrombus in Behçet's disease is an extremely rare manifestation. We report two such cases. A 20-year-old man presented with dyspnoea, cough and haemoptysis. Right heart thrombus associated with pulmonary artery aneurysm and thromboembolism was identified by helical CT and transoesophageal echocardiography. The second case was a 29-year-old male admitted for fever and chest pain. A diagnosis of right atrial thrombosis associated with pulmonary embolism and hyperhomocysteinemia was made. Due to the absence of haemodynamic compromise, medical management consisting of immunosupressive and anticoagulation therapy was adopted which resulted in complete dissolution of the thrombus with dramatic clinical improvement in both cases of clinical status. Conclusion intracardiac thrombus is a rare complication of Behçet's disease. As shown in our patients, medical treatment should be considered as the first line.
-
DEFF Research Database (Denmark)
Clemmensen, Tor Skibsted; Holm, Niels Ramsing; Eiskjær, Hans
2016-01-01
The case illustrates the possible link between coronary spasms, intraluminal thrombus formation, and widespread organized and layered thrombi in HTx patients. Furthermore, the case underlines the clinical value of OCT as a novel method for high-resolution vessel imaging in heart-transplanted (HTx...
-
Retrievable Vena Cava Filters in Major Trauma Patients: Prevalence of Thrombus Within the Filter
International Nuclear Information System (INIS)
Mahrer, Arie; Zippel, Douglas; Garniek, Alexander; Golan, Gil; Bensaid, Paul; Simon, Daniel; Rimon, Uri
2008-01-01
The purpose of this study was to report the prevalence of thrombus within a retrievable vena cava filter inserted prophylactically in major trauma patients referred for filter extraction. Between November 2002 and August 2005, 80 retrievable inferior vena cava filters (68 Optease and 12 Gunther-Tulip) were inserted into critically injured trauma patients (mean injury severity score 33.5). The filters were inserted within 1 to 6 (mean 2) days of injury. Thirty-seven patients were referred for filter removal (32 with Optease and 5 with Gunther-Tulip). The indwelling time was 7 to 22 (mean 13) days. All patients underwent inferior vena cavography prior to filter removal. There were no insertion-related complications and all filters were successfully deployed. Forty-three (54%) of the 80 patients were not referred for filter removal, as these patients continued to have contraindications to anticoagulation. Thirty-seven patients (46%) were referred for filter removal. In eight of them (22%) a large thrombus was seen within the filters and they were left in place, all with the Optease device. The other 29 filters (36%) were removed uneventfully.We conclude that the relatively high prevalence of intrafilter thrombi with the Optease filter may be explained by either spontaneous thrombus formation or captured emboli.
-
Novel aspects of the pathogenesis of aneurysms of the abdominal aorta in humans
DEFF Research Database (Denmark)
Michel, Jean-Baptiste; Martin-Ventura, José-Luis; Egido, Jesus
2011-01-01
and the adventitial response in the development of human AAA. The intraluminal thrombus exerts its pathogenic effect through platelet activation, fibrin formation, binding of plasminogen and its activators, and trapping of erythrocytes and neutrophils, leading to oxidative and proteolytic injury of the arterial wall...... arterial wall rupture. The roles of matrix metalloproteinases and plasmin generation in progression of AAA have been demonstrated both in animal models and in clinical studies. In the present review, we highlight recent studies addressing the role of the haemoglobin-rich, intraluminal thrombus...
-
Traversing boundaries: thrombus in transit with paradoxical embolism
Directory of Open Access Journals (Sweden)
Varun Miriyala
2016-09-01
Full Text Available A 72-year-old male is diagnosed with paradoxical embolus after he presented with concurrent deep vein thrombosis, stroke, and multiple arterial emboli in the presence of a patent foramen ovale (PFO. Paradoxical embolus requires the passage of a thrombus from the venous into the arterial circulation through a right-to-left shunt leading to systemic embolism. But, despite the high incidence of PFO (27.3% across all age groups by autopsy, paradoxical embolism (PDE is uncommon, representing <2% of all arterial emboli. We present a case report where a thrombus has been directly observed passing through the PFO during an echocardiogram study; thus, clearly delineating the true cause of multiple thromboemboli and stoke in our patient. Subsequent Transesophageal Echocardiography (TEE also interestingly showed the thrombus in transit in the aorta and pulmonary artery.
-
Method of cell transplantation promoting the organization of intraarterial thrombus.
Hirano, Koji; Shimono, Takatsugu; Imanaka-Yoshida, Kyoko; Miyamoto, Keiichi; Fujinaga, Kazuya; Kajimoto, Masaki; Miyake, Yoichiro; Nishikawa, Masakatsu; Yoshida, Toshimichi; Uchida, Atsumasa; Shimpo, Hideto; Yada, Isao; Hirata, Hitoshi
2005-08-30
Endovascular aortic repairs have been developed as less invasive treatments for aortic aneurysms. Some aneurismal cavities, however, remain without organization, causing a re-expansion of the aneurysms. We studied cell transplantation into the aneurismal sac to promote the organization of thrombus for the complete healing of aneurysms. Skin fibroblasts and skeletal myoblasts were isolated from rats for cell transplantation. An intraarterial thrombus model was made by ligation of the carotid artery. Culture medium (medium group, n=11), collagen gel (gel group, n=11), fibroblasts with collagen gel (F group, n=15), myoblasts with collagen gel (M group, n=12), or mixture of fibroblasts and myoblasts with collagen gel (F+M group, n=14) were injected into the thrombus. After 28 days, histologically, the arterial lumens of the F and M groups were partly filled with fibrous tissues, whereas in the F+M group organization was almost completed and luminal sizes diminished. Immunohistochemical staining demonstrated that alpha-smooth muscle actin-positive cells were more abundantly contained in the organized area of the F+M group than in the other groups. We also analyzed cellular function in vitro with immunofluorescence; coculture of fibroblasts and myoblasts showed that the fraction of alpha-smooth muscle actin-positive fibroblasts increased. This phenomenon accounts for the rapid organization of thrombus in the F+M group in vivo. Cell transplantation accelerated thrombus organization. Especially, myoblasts enhanced differentiation of fibroblasts into myofibroblasts, contributing to rapid thrombus organization. Cell transplantation into unorganized spaces seems applicable to endovascular treatment of aneurysms.
-
Directory of Open Access Journals (Sweden)
Takeshi Tsuda
2017-01-01
Full Text Available Danon disease is a rare X-linked dominant skeletal and cardiac muscle disorder presenting with hypertrophic cardiomyopathy, Wolf-Parkinson-White syndrome, skeletal myopathy, and mild intellectual disability. Early morbidity and mortality due to heart failure or sudden death are known in Danon disease, more in males than in females. Here, we present a 17-year-old female adolescent with Danon disease and severe concentric hypertrophy with normal left ventricular (LV systolic function, who has been complaining of intermittent headache and weakness for about 3 years, initially diagnosed with hemiplegic migraine. Subsequently, her neurological manifestation progressed to transient ischemic attack (TIA and eventually to ischemic stroke confirmed by CT scan with 1-day history of expressive aphasia followed by persistent left side weakness and numbness. Detailed echocardiogram for the first time revealed a small LV apical thrombus with unchanged severe biventricular hypertrophy and normal systolic function. This unexpected LV apical thrombus may be associated with a wide spectrum of neurological deficits ranging from TIA to ischemic stroke in Danon disease. Possibility of cerebral ischemic events should be suspected in Danon disease when presenting with neurological deficits even with normal systolic function. Careful assessment for LV apical thrombus is warranted in such cases.
-
Fibrin d-dimer concentration, deep vein thrombosis symptom duration, and venous thrombus volume.
Kurklinsky, Andrew K; Kalsi, Henna; Wysokinski, Waldemar E; Mauck, Karen F; Bhagra, Anjali; Havyer, Rachel D; Thompson, Carrie A; Hayes, Sharonne N; McBane, Robert D
2011-04-01
To determine the relationship between fibrin D-dimer levels, symptom duration, and thrombus volume, consecutive patients with incident deep venous thrombosis (DVT) were evaluated. In a cross-sectional study design, patient symptom onset was determined by careful patient questioning. Venous thrombosis was confirmed by compression duplex ultrasonography. Thrombus volume was estimated based on patient's femur length using a forensic anthropology method. Fibrin D-dimer was measured by latex immunoassay. 72 consecutive patients with confirmed leg DVT agreed to participate. The median symptom duration at the time of diagnosis was 10 days. The median D-dimer concentration was 1050 ng/dL. The median thrombus volume was 12.92 cm(3). D-Dimer levels correlated with estimated thrombus volume (P venous thrombosis and correlates with thrombus volume.
-
Glycoprotein Ibα clustering in platelet storage and function
Gitz, E.
2013-01-01
Platelets are anucleated, discoid-shaped cells that play an essential role in the formation of a hemostatic plug to prevent blood loss from injured vessels. Initial platelet arrest at the damaged arterial vessel wall is mediated through the interaction between the platelet receptor glycoprotein (GP)
-
Ma, Junhao; Li, Xinxi; Wang, Yang; Yang, Zhenwei; Luo, Jun
2017-12-01
Anticoagulant therapy is commonly used for the prevention and treatment of patients with deep venous thrombus. Evidence has shown that rivaroxaban is a potential oral anticoagulant drug for the acute treatment of venous thromboembolism. However, the rivaroxaban-mediated molecular mechanism involved in the progression of deep venous thrombosis has not been investigated. In the present study, we investigated the efficacy of rivaroxaban and the underlying signaling pathways in the prevention and treatment of rats with deep venous thrombosis. A rat model with deep vein thrombus formation was established and received treatment with rivaroxaban or PBS as control. The thrombin-activatable fibrinolysis inhibitor (TAFI) and plasminogen activator inhibitor-1 (PAI-1) were analyzed both in vitro and in vivo. The progression of thrombosis and stroke was evaluated after treatment with rivaroxaban or PBS. Nuclear factor-κB (NF-κB) signaling pathway in venous endothelial cells and in the rat model of deep venous thrombus was assessed. The therapeutic effects of rivaroxaban were evaluated as determined by changes in deep venous thrombosis in the rat model. Our results showed that rivaroxaban markedly inhibited TAFI and PAI-1 expression levels, neutrophils, tissue factor, neutrophil extracellular traps (NETs), myeloperoxidase and macrophages in venous endothelial cells and in the rat model of deep venous thrombus. Expression levels of ADP, PAIs, von Willebrand factor (vWF) and thromboxane were downregulated in vein endothelial cells and in serum from the experimental rats. Importantly, the incidences of inferior vena cava filter thrombus were protected by rivaroxaban during heparin-induced thrombolysis deep venous thrombosis in the rat model. We observed that activity of the NF-κB signaling pathway was inhibited by rivaroxaban in vein endothelial cells both in vitro and in vivo. Notably, immunohistology indicated that rivaroxaban attenuated deep venous thrombosis and the
-
Live-cell Imaging of Platelet Degranulation and Secretion Under Flow
Barendrecht, Arjan D; Verhoef, Johan J F; Pignatelli, Silvia; Pasterkamp, Gerard; Heijnen, Harry F G; Maas, Coen
2017-01-01
Blood platelets are essential players in hemostasis, the formation of thrombi to seal vascular breaches. They are also involved in thrombosis, the formation of thrombi that occlude the vasculature and injure organs, with life-threatening consequences. This motivates scientific research on platelet
-
Platelet kinetics with indium-111 platelets: comparison with chromium-51 platelets
International Nuclear Information System (INIS)
Peters, A.M.; Lavender, J.P.
1983-01-01
The application of 111In-oxine to platelet labeling has contributed to the understanding of platelet kinetics along three lines: 1. It allows the measurement of new parameters of splenic function, such as the intrasplenic platelet transit time, which has shed new light on the physiology of splenic blood cell handling. 2. It facilitates the measurement of platelet life span in conditions, such as ITP, in which 51Cr may undergo undesirable elution from the platelet as a result of platelet-antibody interaction. 3. It allows the determination of the fate of platelets, that is, the site of platelet destruction in conditions in which reduced platelet life span is associated with abnormal platelet consumption, as a result of either premature destruction of ''abnormal'' platelets by the RE system, or the consumption (or destruction) of normal platelets after their interaction with an abnormal vasculature. Future research using 111In platelets may yield further valuable information on the control as well as the significance of intrasplenic platelet pooling, on the role of platelets in the development of chronic vascular lesions, and on the sites of platelet destruction in ITP. With regard to the latter, methods will have to be developed for harvesting sufficient platelets representative of the total circulating platelet population from severely thrombocytopenic patients for autologous platelet labeling. This would avoid the use of homologous platelets, which is likely to be responsible for some of the contradictory data relating to the use of radiolabeled platelet studies for the prediction of the response of patients with ITP to splenectomy
-
Floating arterial thrombus related stroke treated by intravenous thrombolysis.
Vanacker, P; Cordier, M; Janbieh, J; Federau, C; Michel, P
2014-01-01
The effects of intravenous thrombolysis on floating thrombi in cervical and intracranial arteries of acute ischemic stroke patients are unknown. Similarly, the best prevention methods of early recurrences remain controversial. This study aimed to describe the clinical and radiological outcome of thrombolyzed strokes with floating thrombi. We retrospectively analyzed all thrombolyzed stroke patients in our institution between 2003 and 2010 with floating thrombi on acute CT-angiography before the intravenous thrombolysis. The floating thrombus was diagnosed if an elongated thrombus of at least 5 mm length, completely surrounded by contrast on supra-aortic neck or intracerebral arteries, was present on CT-angiography. Demographics, vascular risk factors, and comorbidities were recorded and stroke etiology was determined after a standardized workup. Repeat arterial imaging was performed by CTA at 24 h or before if clinical worsening was noted and then by Doppler and MRA during the first week and at four months. Of 409 thrombolyzed stroke patients undergoing acute CT Angiography, seven (1.7%) had a floating thrombus; of these seven, six had it in the anterior circulation. Demographics, risk factors and stroke severity of these patients were comparable to the other thrombolyzed patients. After intravenous thrombolysis, the floating thrombi resolved completely at 24 h in four of the patients, whereas one had an early recurrent stroke and one developed progressive worsening. One patient developed early occlusion of the carotid artery with floating thrombus and subsequently a TIA. The two patients with a stable floating thrombus had no clinical recurrences. In the literature, only one of four reported cases were found to have a thrombolysis-related early recurrence. Long-term outcome seemed similar in thrombolyzed patients with floating thrombus, despite a possible increase of very early recurrence. It remains to be established whether acute mechanical thrombectomy could be
-
Zhang, J; Yuan, T; Zheng, N; Zhou, Y; Hogan, M V; Wang, J H-C
2017-04-01
After an injury, the biological reattachment of tendon to bone is a challenge because healing takes place between a soft (tendon) and a hard (bone) tissue. Even after healing, the transition zone in the enthesis is not completely regenerated, making it susceptible to re-injury. In this study, we aimed to regenerate Achilles tendon entheses (ATEs) in wounded rats using a combination of kartogenin (KGN) and platelet-rich plasma (PRP). Wounds created in rat ATEs were given three different treatments: kartogenin platelet-rich plasma (KGN-PRP); PRP; or saline (control), followed by histological and immunochemical analyses, and mechanical testing of the rat ATEs after three months of healing. Histological analysis showed well organised arrangement of collagen fibres and proteoglycan formation in the wounded ATEs in the KGN-PRP group. Furthermore, immunohistochemical analysis revealed fibrocartilage formation in the KGN-PRP-treated ATEs, evidenced by the presence of both collagen I and II in the healed ATE. Larger positively stained collagen III areas were found in both PRP and saline groups than those in the KGN-PRP group. Chondrocyte-related genes, SOX9 and collagen II, and tenocyte-related genes, collagen I and scleraxis (SCX), were also upregulated by KGN-PRP. Moreover, mechanical testing results showed higher ultimate tensile strength in the KGN-PRP group than in the saline control group. In contrast, PRP treatment appeared to have healed the injured ATE but induced no apparent formation of fibrocartilage. The saline-treated group showed poor healing without fibrocartilage tissue formation in the ATEs. Our results show that injection of KGN-PRP induces fibrocartilage formation in the wounded rat ATEs. Hence, KGN-PRP may be a clinically relevant, biological approach to regenerate injured enthesis effectively. Cite this article: J. Zhang, T. Yuan, N. Zheng, Y. Zhou, M. V. Hogan, J. H-C. Wang. The combined use of kartogenin and platelet-rich plasma promotes
-
LENUS (Irish Health Repository)
McCabe, Dominick J H
2004-06-01
Flow cytometric studies suggest that platelets are activated in ischaemic stroke or transient ischaemic attack (TIA). However, few studies have measured circulating leucocyte-platelet complexes in this patient population. Whole blood flow cytometry was used to quantify the expression of CD62P-, CD63-, and PAC1-binding, and the percentages of leucocyte-platelet complexes in acute (1-27 d, n = 79) and convalescent (79-725 d, n = 70) ischaemic cerebrovascular disease (CVD) patients compared with controls without CVD (n = 27). We performed a full blood count, and measured plasma levels of soluble P-selectin, soluble E-selectin, and von Willebrand factor antigen (VWF:Ag) as additional markers of platelet and\\/or endothelial cell activation. The median percentage CD62P expression and the median percentage monocyte-platelet complexes were higher in both acute and convalescent CVD patients than controls (P <\\/= 0.02). The mean white cell count and mean VWF:Ag levels were significantly elevated in the acute and convalescent phases after ischaemic stroke or TIA (P <\\/= 0.02). Otherwise, there was no significant increase in any other marker of platelet or endothelial activation in CVD patients. There was a positive correlation between the percentage expression of CD62P and the percentages of both neutrophil-platelet and monocyte-platelet complexes in the acute phase, and the percentages of all leucocyte-platelet complexes in the convalescent phase after ischaemic CVD. This study provides evidence for ongoing excessive platelet and\\/or endothelial activation in ischaemic CVD patients despite treatment with antithrombotic therapy.
-
The Dynamics of Platelet Activation during the Progression of Streptococcal Sepsis.
Directory of Open Access Journals (Sweden)
Sinead M Hurley
Full Text Available Platelets contribute to inflammation however, the role of platelet activation during the pathophysiological response to invasive bacterial infection and sepsis is not clear. Herein, we have investigated platelet activation in a mouse model of invasive Streptococcus pyogenes infection at 5, 12, and 18 hours post infection and correlated this to parameters of infection. The platelet population in ex-vivo blood samples showed no increased integrin activation or surface presentation of CD62P, however platelet-neutrophil complex formation and plasma levels of CD62P were increased during bacterial dissemination and the progression of sepsis, indicating that platelet activation had occurred in vivo. Platelet-neutrophil complex formation was the most discriminatory marker of platelet activation. Platelet-neutrophil complexes were increased above baseline levels during early sepsis but decreased to significantly lower levels than baseline during late sepsis. The removal of these complexes from the circulation coincided with a significant increase in organ damage and the accumulation of platelets in the liver sinusoids, suggesting that platelet activation in the circulation precedes accumulation of platelets in damaged organs. The results demonstrate that monitoring platelet activation using complementary methods may provide prognostic information during the pathogenesis of invasive S. pyogenes infection.
-
International Nuclear Information System (INIS)
Farman, M. T.; Saghir, T.; Rizvi, N. H.; Khan, N.; Zaman, K. S.; Sial, J. A.; Malik, A.
2014-01-01
Objective: To determine the safety and efficacy of selective thrombus aspiration during Primary Percutaneous Coronary Intervention (PCI). Methods: This observational prospective study was conducted in the catheterization laboratory of a tertiary care cardiovascular centre. A total of 150 consecutive patients who underwent primary PCI were enrolled. Aspiration was done only when thrombus burden was considered significant. After completion of procedure angiographic and electrocardiographic signs were recorded and clinical follow up was documented up to 1 year. Results: No significant difference among the groups was found in age, height, weight and other risk factors like Hypertension, Diabetes Mellitus and Smoking. In general, left anterior descending artery was culprit in 65 % of patients and more than 90 % of culprit vessels had visible thrombus. Multivessel disease was present in 38 % of patients and 22.7% had past history of myocardial infarction. Out of 150 patients 117 (78%) underwent thrombus aspiration. No significant difference was found in ST resolution within 60 minutes (72.6 vs 81.8 %; P<0.285) and myocardial blush grade II and III (41.9 vs 27.3 %; P<0.128). No difference in event free survival was observed among the two groups (80.3 vs 84.8 %; P<0.708) at one year. Conclusion: Selective thrombus aspiration in definite thrombus laden arteries and no aspiration in low or negligible thrombus burden vessels may be a safe and effective strategy in patients undergoing primary PCI. Overall poor risk profile of our patients as compared to western population necessitates further evaluation of this matter in randomized studies. (author)
-
Thrombus length discrepancy on dual-phase CT can predict clinical outcome in acute ischemic stroke
International Nuclear Information System (INIS)
Park, Mina; Kim, Kyung-eun; Lee, Seung-Koo; Shin, Na-Young; Lim, Soo Mee; Song, Dongbeom; Heo, Ji Hoe; Kim, Jin Woo; Oh, Se Won
2016-01-01
The thrombus length may be overestimated on early arterial computed tomography angiography (CTA) depending on the collateral status. We evaluated the value of a grading system based on the thrombus length discrepancy on dual-phase CT in outcome prediction. Forty-eight acute ischemic stroke patients with M1 occlusion were included. Dual-phase CT protocol encompassed non-contrast enhanced CT, CTA with a bolus tracking technique, and delayed contrast enhanced CT (CECT) performed 40s after contrast injection. The thrombus length discrepancy between CTA and CECT was graded by using a three-point scale: G0 = no difference; G1 = no difference in thrombus length, but in attenuation distal to thrombus; G2 = difference in thrombus length. Univariate and multivariate analyses were performed to define independent predictors of poor clinical outcome at 3 months. The thrombus discrepancy grade showed significant linear relationships with both the collateral status (P = 0.008) and the presence of antegrade flow on DSA (P = 0.010) with good interobserver agreement (κ = 0.868). In a multivariate model, the presence of thrombus length discrepancy (G2) was an independent predictor of poor clinical outcome [odds ratio = 11.474 (1.350-97.547); P =0.025]. The presence of thrombus length discrepancy on dual-phase CT may be a useful predictor of unfavourable clinical outcome in acute M1 occlusion patients. (orig.)
-
Hatakeyama, Ichiro; Marukawa, Eriko; Takahashi, Yukinobu; Omura, Ken
2014-02-01
Alveolar bone resorption generally occurs during healing after tooth extraction. This study aimed to evaluate the effects of platelet-poor plasma (PPP), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) on healing in a ridge-augmentation model of the canine socket with dehiscence of the buccal wall. The third mandibular premolars of 12 beagle dogs were extracted and a 3 mm buccal dehiscence from the alveolar crest to the buccal wall of the extraction socket was created. These sockets were then divided into four groups on the basis of the material used to fill the sockets: PPP, PRP, PRF, and control (no graft material) groups. Results were evaluated at 4 and 8 weeks after surgery. The ultrastructural morphology and constructs of each blood product were studied by a scanning electron microscope (SEM) or calculating concentrations of platelets, fibrinogen, platelet-derived growth factor, and transforming growth factor-β. A total of five microcomputed tomography images of specimens were selected for measurement, and the area occupied by the newly formed bone as well as the horizontal bone width were measured. Moreover, decalcified tissue specimens from each defect were analyzed histologically. The median area of new bone at 4 and 8 weeks and median horizontal bone width at 8 weeks were the highest in the PPP group. However, bone maturation in the PRF and the PRP groups was more progressed than that in the PPP and control groups. By SEM findings, the PRF group showed a more highly condensed fibrin fiber network that was regularly arranged when compared with the PPP and PRP groups. The growth factors released from platelets in PRP indicated higher concentrations than that in PRF. Under more severe conditions for bone formation, as in this experiment, the growth factors released from platelets had a negative effect on bone formation. This study showed that PPP is an effective material for the preservation of sockets with buccal dehiscence.
-
Wang, Yongzhi; Zhang, Su; Luo, Lingtao; Norström, Eva; Braun, Oscar Ö; Mörgelin, Matthias; Thorlacius, Henrik
2018-02-01
Sepsis is associated with dysfunctional coagulation. Recent data suggest that platelets play a role in sepsis by promoting neutrophil accumulation. Herein, we show that cecal ligation and puncture (CLP) triggered systemic inflammation, which is characterized by formation of IL-6 and CXC chemokines as well as neutrophil accumulation in the lung. Platelet depletion decreased neutrophil accumulation, IL-6, and CXC chemokines formation in septic lungs. Depletion of platelets increased peak thrombin formation and total thrombin generation (TG) in plasma from septic animals. CLP elevated circulating levels of platelet-derived microparticles (PMPs). In vitro generated PMPs were a potent inducer of TG. Interestingly, in vitro wild-type recombinant annexin V abolished PMP-induced thrombin formation whereas a mutant annexin V protein, which does not bind to phosphatidylserine (PS), had no effect. Administration of wild-type, but not mutant annexin V, significantly inhibited thrombin formation in septic animals. Moreover, CLP-induced formation of thrombin-antithrombin complexes were reduced in platelet-depleted mice and in animals pretreated with annexin V. PMP-induced TG attenuated in FXII- and FVII-deficient plasma. These findings suggest that sepsis-induced TG is dependent on platelets. Moreover, PMPs formed in sepsis are a potent inducer of TG via PS exposure, and activation of both the intrinsic and extrinsic pathway of coagulation. In conclusion, these observations suggest that PMPs and PS play an important role in dysfunctional coagulation in abdominal sepsis. © 2017 Wiley Periodicals, Inc.
-
Journal of Special Operations Medicine, Volume 2, Edition 2
2002-01-01
course in North Miami for Nitrox, Technical Nitrox, Deep Air, Trimix and decompression diving. He is board certified in anesthesiology and critical...such as a patent foramen ovale (PFO) or arteriovenous malformations in which venous blood mixes with arterial blood (bypassing the lungs). The lungs...cascade. This activation leads to fibrin clot formation. In addition, thrombus formation occurs de novo as a result of platelets and fibrin
-
Energy Technology Data Exchange (ETDEWEB)
Mori, H; Futagawa, S; Hayashi, K; Amagasaki, Y; Ochi, M [Nagasaki Univ. (Japan). School of Medicine
1982-04-01
Nine cases of hepatocellular carcinoma which have invaded the intra- and extrahepatic portal vein were evaluated by computed tomography (CT) and ultrasonography (US). The outstanding CT and sonographic features of the portal vein tumor thrombus were described. In CT, contrast opacification of normal portal vein and its major tributaries were not observed, and they were replaced by a soft tissue density mass representing the tumor thrombus. The thrombus measured 35 - 45 Hounsfield units (HU) in precontrast scans and 60 - 80 HU in postcontrast scans. The portal vein tumor thrombus showed a branched pattern of low density in porta hepatis and intrahepatic region due to differences in attenuation coefficients of the thrombus and adjacent noncancerous hepatic parenchyma on postcontrast scans. In ultrasound study, tumor thrombus was recognized as an echogenic solid mass in the porta hepatis obliterating the normal portal venous structures, or as an intraluminal solid mass in the dilated portal vein and its branches. Numerous collateral venous channels surrounding the thrombosed portal vein were also demonstrated on both CT and US. Particular emphasis was placed on the clinical implications of these non-invasive detection of the portal vein tumor thrombosis in patients with hepatocellular carcinoma.
-
Niacin and biosynthesis of PGD₂ by platelet COX-1 in mice and humans
DEFF Research Database (Denmark)
Song, Wen-Liang; Stubbe, Jane; Ricciotti, Emanuela
2012-01-01
during platelet activation in humans and, although vascular expression of DP1 is conserved between humans and mice, platelet DP1 is not present in mice. Despite this, DP1 deletion in mice augmented aneurysm formation and the hypertensive response to Ang II and accelerated atherogenesis and thrombogenesis....... Furthermore, COX inhibitors in humans, as well as platelet depletion, COX-1 knockdown, and COX-2 deletion in mice, revealed that niacin evoked platelet COX-1-derived PGD₂ biosynthesis. Finally, ADP-induced spreading on fibrinogen was augmented by niacin in washed human platelets, coincident with increased...... thromboxane (Tx) formation. However, in platelet-rich plasma, where formation of both Tx and PGD₂ was increased, spreading was not as pronounced and was inhibited by DP1 activation. Thus, PGD₂, like PGI₂, may function as a homeostatic response to thrombogenic and hypertensive stimuli and may have particular...
-
Radioimmune assay of human platelet prostaglandin synthetase
International Nuclear Information System (INIS)
Roth, G.J.; Machuga, E.T.
1982-01-01
Normal platelet function depends, in part, on platelet PG synthesis. PG synthetase (cyclo-oxygenase) catalyzes the first step in PG synthesis, the formation of PGH 2 from arachidonic acid. Inhibition of the enzyme by ASA results in an abnormality in the platelet release reaction. Patients with pparent congenital abnormalities in the enzyme have been described, and the effects have been referred to as ''aspirin-like'' defects of the platelet function. These patients lack platelet PG synthetase activity, but the actual content of PG synthetase protein in these individuals' platelets is unknown. Therefore an RIA for human platelet PG synthetase would provide new information, useful in assessing the aspirin-like defects of platelet function. An RIA for human platelet PG synthetase is described. The assay utilizes a rabbit antibody directed against the enzyme and [ 125 I]-labelled sheep PG synthetase as antigen. The human platelet enzyme is assayed by its ability to inhibit precipitation of the [ 125 I]antigen. The assay is sensitive to 1 ng of enzyme. By the immune assay, human platelets contain approximately 1200 ng of PG synethetase protein per 1.5 mg of platelet protein (approximately 10 9 platelets). This content corresponds to 10,000 enzyme molecules per platelet. The assay provides a rapid and convenient assay for the human platelet enzyme, and it can be applied to the assessment of patients with apparent platelet PG synthetase (cyclo-oxygenase) deficiency
-
International Nuclear Information System (INIS)
Santos, Emilie M.M.; Yoo, Albert J.; Beenen, Ludo F.; Majoie, Charles B.; Berkhemer, Olvert A.; Blanken, Mark D. den; Wismans, Carrie; Niessen, Wiro J.; Marquering, Henk A.
2016-01-01
Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert observers. For 132 consecutive patients with acute ischemic stroke, three experts and two trained observers determined thrombus density by placing three standardized regions of interest (ROIs) in the thrombus and corresponding contralateral arterial segment. Subsequently, absolute and relative thrombus densities were determined using either one or three ROIs. Intraclass correlation coefficient (ICC) was determined, and Bland-Altman analysis was performed to evaluate interobserver and intermethod agreement. Accuracy of the trained observer was evaluated with a reference expert observer using the same statistical analysis. The highest interobserver agreement was obtained for absolute thrombus measurements using three ROIs (ICCs ranging from 0.54 to 0.91). In general, interobserver agreement was lower for relative measurements, and for using one instead of three ROIs. Interobserver agreement of trained non-experts and experts was similar. Accuracy of the trained observer measurements was comparable to the expert interobserver agreement and was better for absolute measurements and with three ROIs. The agreement between the one ROI and three ROI methods was good. Absolute thrombus density measurement has superior interobserver agreement compared to relative density measurement. Interobserver variation is smaller when multiple ROIs are used. Trained non-expert observers can accurately and reproducibly assess absolute thrombus densities using three ROIs. (orig.)
-
Energy Technology Data Exchange (ETDEWEB)
Santos, Emilie M.M. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, P.O. Box 2040, Rotterdam (Netherlands); Department of Radiology, AMC, Amsterdam (Netherlands); Yoo, Albert J. [Texas Stroke Institute, Plano, TX (United States); Beenen, Ludo F.; Majoie, Charles B. [Department of Radiology, AMC, Amsterdam (Netherlands); Berkhemer, Olvert A. [Department of Radiology, AMC, Amsterdam (Netherlands); Department of Neurology, Erasmus MC, Rotterdam (Netherlands); Blanken, Mark D. den; Wismans, Carrie [AMC, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Niessen, Wiro J. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, P.O. Box 2040, Rotterdam (Netherlands); Delft University of Technology, Faculty of Applied Sciences, Delft (Netherlands); Marquering, Henk A. [Department of Radiology, AMC, Amsterdam (Netherlands); AMC, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Collaboration: on behalf of the MR CLEAN investigators
2016-02-15
Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert observers. For 132 consecutive patients with acute ischemic stroke, three experts and two trained observers determined thrombus density by placing three standardized regions of interest (ROIs) in the thrombus and corresponding contralateral arterial segment. Subsequently, absolute and relative thrombus densities were determined using either one or three ROIs. Intraclass correlation coefficient (ICC) was determined, and Bland-Altman analysis was performed to evaluate interobserver and intermethod agreement. Accuracy of the trained observer was evaluated with a reference expert observer using the same statistical analysis. The highest interobserver agreement was obtained for absolute thrombus measurements using three ROIs (ICCs ranging from 0.54 to 0.91). In general, interobserver agreement was lower for relative measurements, and for using one instead of three ROIs. Interobserver agreement of trained non-experts and experts was similar. Accuracy of the trained observer measurements was comparable to the expert interobserver agreement and was better for absolute measurements and with three ROIs. The agreement between the one ROI and three ROI methods was good. Absolute thrombus density measurement has superior interobserver agreement compared to relative density measurement. Interobserver variation is smaller when multiple ROIs are used. Trained non-expert observers can accurately and reproducibly assess absolute thrombus densities using three ROIs. (orig.)
-
GAS6/TAM Pathway Signaling in Hemostasis and Thrombosis.
Law, Luke A; Graham, Douglas K; Di Paola, Jorge; Branchford, Brian R
2018-01-01
The GAS6/TYRO3-AXL-MERTK (TAM) signaling pathway is essential for full and sustained platelet activation, as well as thrombus stabilization. Inhibition of this pathway decreases platelet aggregation, shape change, clot retraction, aggregate formation under flow conditions, and surface expression of activation markers. Transgenic mice deficient in GAS6, or any of the TAM family of receptors that engage this ligand, exhibit in vivo protection against arterial and venous thrombosis but do not demonstrate either spontaneous or prolonged bleeding compared to their wild-type counterparts. Comparable results are observed in wild-type mice treated with pharmacological inhibitors of the GAS6-TAM pathway. Thus, GAS6/TAM inhibition offers an attractive novel therapeutic option that may allow for a moderate reduction in platelet activation and decreased thrombosis while still permitting the primary hemostatic function of platelet plug formation.
-
E.M.M. Santos (Emilie M.); A.J. Yoo (Albert J.); L.F.M. Beenen (Ludo); O.A. Berkhemer (Olvert); M.D. Den Blanken (Mark D.); C. Wismans (Carrie); W.J. Niessen (Wiro); C.B. Majoie (Charles); H. Marquering (Henk)
2016-01-01
textabstractIntroduction: Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by
-
Identification of intracardiac thrombi in stroke patients with indium-111 platelet scintigraphy
International Nuclear Information System (INIS)
Kessler, C.; Henningsen, H.; Reuther, R.; Kimmig, B.; Roesch, M.
1987-01-01
Platelet scintigraphy (PSC) with indium-111 labelled platelets has been confirmed as an adequate method for the detection of intracardiac thrombi in patients with heart disease. We performed PSC of the heart and the neck vessels in 27 stroke patients with suspected cardiac embolism and as control on 10 patients with atherosclerotic lesions of the carotid arteries without evidence of heart disease. The carotid PSC was positive in 6 of 10 patients with carotid disease, and twice in the 27 with suspected cardiac embolism. In these 27 the PSC of the heart indicated pathological conditions 13 times. Pathological platelet accumulations could be visualized in 3 cases in the atrial space, in 9 cases in the region of the left ventricle, and once at the aortic valve. Scintigraphy was negative in all 10 patients with atherosclerosis of the neck vessels. The two-dimensional echocardiography revealed pathological findings in 8 of the 13 patients with positive heart PSC (3 with intraventricular thrombi, 3 with valvular disease, 2 with decreased ventricular contractility) and was normal in the 10 control patients. Open-heart surgery was performed in 2 patients with pathological PSC and revealed an intracardiac thrombus. Three of 4 patients with positive atrial PSC showed mitral or aortic valve disease. These results suggest that PSC can provide a valuable method for detecting cardiac thrombi in stroke patients
-
Chabasse, Christine; Siefert, Suzanne A.; Chaudry, Mohammed; Hoofnagle, Mark H.; Lal, Brajesh K.; Sarkar, Rajabrata
2016-01-01
Objective We examined the role of thrombus recanalization and ongoing blood flow in the process of thrombus resolution by comparing two murine in vivo models of deep venous thrombosis. Design of study In CD1 mice, we performed surgical inferior vena cava (IVC) ligation (stasis thrombosis), stenosis (thrombosis with recanalization) or sham procedure. We analyzed thrombus weight over time as a measure of thrombus resolution, and quantified the mRNA and protein levels of Membrane-Type Matrix Metalloproteinases (MT-MMPs) as well as effectors of the plasmin complex at day 4, 8 and 12 post-surgery. Results Despite similar initial thrombus size, the presence of ongoing blood flow (stenosis model) was associated with a 45.91% subsequent improvement in thrombus resolution at day 8, and 12.57% at day 12, as compared with stasis thrombosis (ligation model). Immunoblot and real-time PCR demonstrated a difference in MMP-2 and MMP-9 activity at day 8 between the two models (P=.03 and P=.006 respectively), as well as a difference in MT2-MMP gene expression at day 8 (P=.044) and day 12 (P=0.03) and MT1-MMP protein expression at day 4 (P=.021). Histological analyses revealed distinct areas of recanalization in the thrombi of the stenosis model compared to the ligation model, as well as the recruitment of inflammatory cells, especially macrophages, and a focal pattern of localized expression of MT1-MMP and MT3-MMP proteins surrounding the areas of recanalization in the stenosis model. Conclusions Recanalization and ongoing blood flow accelerate deep venous thrombus resolution in vivo, and are associated with distinct patterns of MT1- and MT3-MMP expression and macrophages localization in areas of intra-thrombus recanalization. PMID:26993683
-
Platelet activation and platelet-leukocyte interaction in dogs naturally infected with Babesia rossi
DEFF Research Database (Denmark)
Goddard, Amelia; Leisewitz, Andrew L; Kristensen, Annemarie Thuri
2015-01-01
EDTA as anticoagulant. Activated platelets and PLA formation were detected by measuring surface expression of P-selectin (CD62P) on platelets, monocytes and neutrophils. Of the Babesia-infected dogs, 29 survived and seven died. The percentage of CD62P-positive monocytes was significantly higher (P = 0.......036) in the Babesia-infected dogs (54%) than in healthy control dogs (35.3%). However, there were no significant differences between the Babesia-infected and control groups for CD62P-positive platelets (4.9% and 1.2%, respectively) and CD62P-positive neutrophils (28.3% and 17.9%, respectively). The percentage of CD62...... groups for the percentage of CD62P-positive platelets (survivors 4.8%; non-survivors 5.3%; controls 1.2%) or CD62P-positive neutrophils (survivors 31.6%; non-survivors 5.6%; controls 17.9%). In conclusion, Babesia-infected dogs, specifically dogs that survived, had a significantly increased percentage...
-
Santos, Emilie M. M.; Yoo, Albert J.; Beenen, Ludo F.; Berkhemer, Olvert A.; den Blanken, Mark D.; Wismans, Carrie; Niessen, Wiro J.; Majoie, Charles B.; Marquering, Henk A.; Fransen, Puck S. S.; Beumer, Debbie; van den Berg, Lucie A.; Lingsma, Hester F.; Schonewille, Wouter J.; Vos, Jan Albert; Nederkoorn, Paul J.; Wermer, Marieke J. H.; van Walderveen, Marianne A. A.; Staals, Julie; Hofmeijer, Jeannette; van Oostayen, Jacques A.; Lycklama à Nijeholt, Geert J.; Boiten, Jelis; Brouwer, Patrick A.; Emmer, Bart J.; de Bruijn, Sebastiaan F.; van Dijk, Lukas C.; Kappelle, L. Jaap; Lo, Rob H.; van Dijk, Ewoud J.; de Vries, Joost; de Kort, Paul L. M.; van den Berg, Jan S. P.; A A M van Hasselt, Boudewijn; Aerden, Leo A. M.; Dallinga, René J.; Visser, Marieke C.; Bot, Joseph C. J.; Vroomen, Patrick C.; Eshghi, Omid; Schreuder, Tobien H. C. M. L.; Heijboer, Roel J. J.; Keizer, Koos; Tielbeek, Alexander V.; Hertog, Heleen M. Den; Gerrits, Dick G.; van den Berg-Vos, Renske M.; Karas, Giorgos B.; Steyerberg, Ewout W.; Flach, H. Zwenneke; Sprengers, Marieke E. S.; Jenniskens, Sjoerd F. M.; van den Berg, René; Koudstaal, Peter J.; van Zwam, Wim H.; Roos, Yvo B. W. E. M.; van der Lugt, Aad; van Oostenbrugge, Robert J.; Dippel, Diederik W. J.
2016-01-01
Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert
-
Santos, E.M.; Yoo, A.J.; Beenen, L.F.; Berkhemer, O.A.; Blanken, M.D. den; Wismans, C.; Niessen, W.J.; Majoie, C.B.; Marquering, H.A.; Dijk, E.J. van; et al.,
2016-01-01
INTRODUCTION: Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and
-
Chen, Chia-Yuan; Antón, Raúl; Hung, Ming-yang; Menon, Prahlad; Finol, Ender A.; Pekkan, Kerem
2014-01-01
The pathology of the human abdominal aortic aneurysm (AAA) and its relationship to the later complication of intraluminal thrombus (ILT) formation remains unclear. The hemodynamics in the diseased abdominal aorta are hypothesized to be a key contributor to the formation and growth of ILT. The objective of this investigation is to establish a reliable 3D flow visualization method with corresponding validation tests with high confidence in order to provide insight into the basic hemodynamic features for a better understanding of hemodynamics in AAA pathology and seek potential treatment for AAA diseases. A stereoscopic particle image velocity (PIV) experiment was conducted using transparent patient-specific experimental AAA models (with and without ILT) at three axial planes. Results show that before ILT formation, a 3D vortex was generated in the AAA phantom. This geometry-related vortex was not observed after the formation of ILT, indicating its possible role in the subsequent appearance of ILT in this patient. It may indicate that a longer residence time of recirculated blood flow in the aortic lumen due to this vortex caused sufficient shear-induced platelet activation to develop ILT and maintain uniform flow conditions. Additionally, two computational fluid dynamics (CFD) modeling codes (Fluent and an in-house cardiovascular CFD code) were compared with the two-dimensional, three-component velocity stereoscopic PIV data. Results showed that correlation coefficients of the out-of-plane velocity data between PIV and both CFD methods are greater than 0.85, demonstrating good quantitative agreement. The stereoscopic PIV study can be utilized as test case templates for ongoing efforts in cardiovascular CFD solver development. Likewise, it is envisaged that the patient-specific data may provide a benchmark for further studying hemodynamics of actual AAA, ILT, and their convolution effects under physiological conditions for clinical applications. PMID:24316984
-
International Nuclear Information System (INIS)
Porto, Italo; Mattesini, Alessio; Valente, Serafina; Prati, Francesco; Crea, Filippo; Bolognese, Leonardo
2015-01-01
Coronary angiography is the “golden standard” imaging technique in interventional cardiology and it is still widely used to guide interventions. A major drawback of this technique, however, is that it is inaccurate in the evaluation and quantification of intracoronary thrombus burden, a critical prognosticator and predictor of intraprocedural complications in acute coronary syndromes. The introduction of optical coherence tomography (OCT) holds the promise of overcoming this important limitation, as near-infrared light is uniquely sensitive to hemoglobin, the pigment of red blood cells trapped in the thrombus. This narrative review will focus on the use of OCT for the assessment, evaluation and quantification of intracoronary thrombosis. - Highlights: • Thrombotic burden in acute coronary syndromes Is not adequately evaluated by standard coronary angiography, whereas Optical Coherence Tomography is exquisitely sensitive to the hemoglobin contained in red blood cells and can be used to precisely quantify thrombus. • Both research and clinical applications have been developed using the OCT-based evaluation of thrombus. In particular, whereas precise quantification scores are useful for comparing antithrombotic therapies in randomized trials, both pharmacological and mechanical, the most important practical applications for OCT-based assessment of thrombus are the individuation of culprit lesions in the context of diffuse atheromata in acute coronary syndromes, and the so-called “delayed stenting” strategies. • Improvements in 3D rendering techniques are on the verge of revolutionizing OCT-based thrombus assessment, allowing extremely precise quantification of the thrombotic burden
-
Energy Technology Data Exchange (ETDEWEB)
Porto, Italo, E-mail: italo.porto@gmail.com [Interventional Cardiology Unit, San Donato Hospital, Arezzo (Italy); Mattesini, Alessio; Valente, Serafina [Interventional Cardiology Unit, Careggi Hospital, Florence (Italy); Prati, Francesco [Interventional Cardiology San Giovanni Hospital, Rome (Italy); CLI foundation (Italy); Crea, Filippo [Department of Cardiovascular Sciences, Catholic University of the Sacred Heart, Rome (Italy); Bolognese, Leonardo [Interventional Cardiology Unit, San Donato Hospital, Arezzo (Italy)
2015-04-15
Coronary angiography is the “golden standard” imaging technique in interventional cardiology and it is still widely used to guide interventions. A major drawback of this technique, however, is that it is inaccurate in the evaluation and quantification of intracoronary thrombus burden, a critical prognosticator and predictor of intraprocedural complications in acute coronary syndromes. The introduction of optical coherence tomography (OCT) holds the promise of overcoming this important limitation, as near-infrared light is uniquely sensitive to hemoglobin, the pigment of red blood cells trapped in the thrombus. This narrative review will focus on the use of OCT for the assessment, evaluation and quantification of intracoronary thrombosis. - Highlights: • Thrombotic burden in acute coronary syndromes Is not adequately evaluated by standard coronary angiography, whereas Optical Coherence Tomography is exquisitely sensitive to the hemoglobin contained in red blood cells and can be used to precisely quantify thrombus. • Both research and clinical applications have been developed using the OCT-based evaluation of thrombus. In particular, whereas precise quantification scores are useful for comparing antithrombotic therapies in randomized trials, both pharmacological and mechanical, the most important practical applications for OCT-based assessment of thrombus are the individuation of culprit lesions in the context of diffuse atheromata in acute coronary syndromes, and the so-called “delayed stenting” strategies. • Improvements in 3D rendering techniques are on the verge of revolutionizing OCT-based thrombus assessment, allowing extremely precise quantification of the thrombotic burden.
-
Platelet-collagen adhesion enhances platelet aggregation induced by binding of VWF to platelets
International Nuclear Information System (INIS)
Laduca, F.M.; Bell, W.R.; Bettigole, R.E.
1987-01-01
Ristocetin-induced platelet aggregation (RIPA) was evaluated in the presence of platelet-collagen adhesion. RIPA of normal donor platelet-rich plasma (PRP) demonstrated a primary wave of aggregation mediated by the binding of von Willebrand factor (VWF) to platelets and a secondary aggregation wave, due to a platelet-release reaction, initiated by VWF-platelet binding and inhibitable by acetylsalicylic acid (ASA). An enhanced RIPA was observed in PRP samples to which collagen had been previously added. These subthreshold concentrations of collagen, which by themselves were insufficient to induce aggregation, caused measurable platelet-collagen adhesion. Subthreshold collagen did not cause microplatelet aggregation, platelet release of [ 3 H]serotonin, or alter the dose-responsive binding of 125 I-labeled VWF to platelets, which occurred with increasing ristocetin concentrations. However, ASA inhibition of the platelet release reaction prevented collagen-enhanced RIPA. These results demonstrate that platelet-collagen adhesion altered the platelet-release reaction induced by the binding of VWF to platelets causing a platelet-release reaction at a level of VWF-platelet binding not normally initiating a secondary aggregation. These findings suggest that platelet-collagen adhesion enhances platelet function mediated by VWF
-
Yunoki, Kei; Naruko, Takahiko; Sugioka, Kenichi; Inaba, Mayumi; Iwasa, Yoko; Komatsu, Ryushi; Itoh, Akira; Haze, Kazuo; Inoue, Takeshi; Yoshiyama, Minoru; Becker, Anton E.; Ueda, Makiko
2012-01-01
Recent studies have demonstrated that erythrocytes are a potential component in atheromatous lesions and thrombus formation in patients with ST-elevation myocardial infarction (STEMI). The purpose of this study was to determine the associations of red blood cell (RBC) component of coronary thrombi
-
Intracardiac thrombus in Behçet’s disease
Directory of Open Access Journals (Sweden)
I. Ben Ghorbel
2016-12-01
Full Text Available Behçet’s disease (BD is a multisystem inflammatory disorder. Intracardiac thrombus (ICT formation is an uncommon but important complication of BD. Of the cases of Behçet’s disease, we selected those with ICT. All patients fulfilled the diagnostic criteria of the International Study Group of Behçet’s disease. The ICT in each case was confirmed by ultrasonography, computed tomography and MRI. Clinical features and laboratory parameters were determined. Among our 518 patients with BD, 8 were diagnosed as having intracardiac thrombus (ICT. All were male; the mean age at the time of the ICT diagnosis was 30.8 years. The main presenting symptoms were hemoptysis, chest pain, and dyspnea. It was associated with pulmonary artery aneurysm and vena cava thrombosis in 3 cases each, pulmonary embolism, and lower limbs deep venous thrombosis in 1 case each. The coexistence of other cardiac complications was as follows: pericarditis in 2 cases, myocarditis, endomyocardial fibrosis, and coronary arteritis with consequent myocardial infarction in one case each. In all cases, echocardiography was sufficient to reach the diagnosis. Chest computed tomography performed in all cases led to the diagnosis of associated pulmonary vasculo-Behçet lesions in 4 cases. All patients received colchicine, anticoagulation, and corticosteroids. Seven patients were on immunosuppressant agents (2 patients received azathioprine and 5 cyclophosphamide. Clinical remission with ICT resolution was observed in 5 cases. Combined immunosuppressive therapy with prednisone and cyclophosphamide might be needed to treat ICT due to BD.
-
Keskin, Muhammed; Kaya, Adnan; Tatlısu, Mustafa Adem; Uzman, Osman; Börklü, Edibe Betül; Çinier, Göksel; Tekkeşin, Ahmet İlker; Türkkan, Ceyhan; Hayıroğlu, Mert İlker; Kozan, Ömer
2017-11-15
Although the long-term clinical benefit of adjunctive thrombus aspiration (TA) during primary percutaneous coronary intervention (PPCI) remains controversial, the impact of TA in patients with large thrombus has not been evaluated. The aim of the present study was to investigate the effect of adjunctive TA during PPCI on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) and a large thrombus. We assessed the effect of adjunctive TA on in-hospital and 3-year clinical outcomes in 627 patients with STEMI and a large thrombus in the native coronary artery. The cumulative 3-year incidence of all-cause death was not significantly different between the 2 groups (91.5% vs 89.0%, log-rank test p = 0.347). After adjusting for confounders, the risk of all-cause death in the TA group was not significantly lower than that in the non-TA group (hazard ratio 1.11, 95% confidence interval 0.60 to 3.54, p = 0.674). The adjusted risks of target lesion revascularization, nonfatal acute myocardial infarction, and stent thrombosis were also not significantly different between the 2 groups. In conclusion, adjunctive TA during PPCI was not associated with better in-hospital and 3-year all-cause deaths in patients with STEMI and a large coronary artery thrombus. Copyright © 2017 Elsevier Inc. All rights reserved.
-
[Recurrent right atrial thrombus in a patient with atrial fibrillation and heart failure].
Elikowski, Waldemar; Wróblewski, Dariusz; Małek-Elikowska, Małgorzata; Mazurek, Andrzej; Foremska-Iciek, Joanna; Łazowski, Stanisław
2015-11-01
Atrial fibrillation and heart failure are factors predisposing to locally formed intracardiac thrombosis, which is usually localized in left-sided chambers. A case report. The authors present a case of a 50-year-old male with permanent atrial fibrillation and dilated cardiomyopathy in whom recurrent right atrial thrombus was observed. Initially, the lesion was detected in echocardiography while he was hospitalized due to extensive right-sided pneumonia. The thrombus was successfully treated with heparin, followed by warfarin. Even though the patient continued warfarin use properly, there was recurrence of the thrombus two years later during a new episode of heart failure exacerbation. Because the thrombus was resistant to intensified anticoagulation, cardiac surgery was needed. A large (30 x 25 mm) pedunculated thrombus, as well as two smaller ones (each of 10 x 10 mm) attached closely to the atrial wall and previously not detected either by echocardiography or by magnetic resonance imaging, were excited. A partially organized pattern of the thrombi in histological examination can explain lack of anticoagulation effectiveness. © 2015 MEDPRESS.
-
Dose- and time-related platelet response with apheresis platelet concentrates and pooled platelets
Directory of Open Access Journals (Sweden)
Mohammad Mizanur Rahman
2017-02-01
Full Text Available This study was carried out to compare the post-transfusion platelet increment between the apheresis platelet concentrate (n=74 and pooled platelets (n=54. Pre- and post-transfusion platelet count of the recipient were carried out by automated hematology analyzer. In apheresis platelet concentrate group, the mean 24 hours post-transfusion platelet increment was 47 x 109/L which was statistically significant (p<0.001. On the other hand, in pooled platelets group, the mean 24 hours post–transfusions platelet count increment was 11.0 x 109/L which was also statistically significant (p<0.001. This study concluded that the transfusion of apheresis platelet concentrate was more useful than the transfusion of pooled platelets in terms of platelet count increment and requirement of donor.
-
Ultrasound active nanoscaled lipid formulations for thrombus lysis.
Becker, Andreas; Marxer, Elena; Brüssler, Jana; Hoormann, Anne Sophia; Kuhnt, Daniela; Bakowsky, Udo; Nimsky, Christopher
2011-04-01
In the present study, we investigated the sonothrombolytic effect of new nanoscaled lipid formulations in human blood clots, using diagnostic ultrasound. Human blood clots of 1 ml were incubated with 1 μl of the different lipid dispersions DPPC/CH, DPPC/PEG40S, DSPC/PEG40S and the commercially available ultrasound contrast agent SonoVue®. Clots were stored for 3 days at 5 °C to obtain maximal clot retraction and lytic resistance. Each clot weight was determined before and after continuous insonation for 1h of insonation at 1.4 MHz. The pressure in the insonation chamber was 80 mm Hg to mimic middle arterial blood pressure. There were no significant differences in thrombus weight before insonation. All nanoscaled formulations and SonoVue® were able to reduce thrombus weight compared to the weight loss of clots that were not insonated but kept under pressure for one hour (p ultrasound enhanced thrombolysis even without thrombolytic drugs. Stable cavitation is a crucial parameter in fragmentation of thrombus architecture. Further studies of physicochemical properties of DSPC/PEG40S are necessary to corroborate our hypothesis. Copyright © 2010 Elsevier B.V. All rights reserved.
-
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, A.; Mayol, A. [Seccion de Neurorradiologia Intervencionista, Servicio de Radiologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Gil-Peralta, A.; Gonzalez-Marcos, J.R. [Servicio de Neurologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Boza, F. [Servicio de Neurofisiologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Ruano, J. [Unidad de Cuidados Intensivos, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain)
2004-04-01
Intraluminal thrombus in the internal carotid artery (ICA) is usually found in patients with severe atheromatous stenosis. Having reviewed 300 carotid angioplasties for symptomatic >70% ICA stenosis, we found three patients (1%) with intraluminal thrombus. Conservative treatment with anticoagulants and double antiplatelet coverage can result in lysis of the thrombus without severe risks. Percutaneous transluminal angioplasty and stenting, preferably with distal protection, can be an excellent alternative to carotid endarterectomy. (orig.)
-
Platelet-activating factor podoplanin: from discovery to drug development.
Takemoto, Ai; Miyata, Kenichi; Fujita, Naoya
2017-06-01
Tumor cell-induced platelet aggregation facilitates hematogenous metastasis by promoting tumor embolization, preventing immunological assaults and shear stress, and the platelet-releasing growth factors support tumor growth and invasion. Podoplanin, also known as Aggrus, is a type I transmembrane mucin-like glycoprotein and is expressed on wide range of tumor cells. Podoplanin has a role in platelet aggregation and metastasis formation through the binding to its platelet receptor, C-type lectin-like receptor 2 (CLEC-2). The podoplanin research was originally started from the cloning of highly metastatic NL-17 subclone from mouse colon 26 cancer cell line and from the establishment of 8F11 monoclonal antibody (mAb) that could neutralize NL-17-induced platelet aggregation and hematogenous metastasis. Later on, podoplanin was identified as the antigen of 8F11 mAb, and its ectopic expression brought to cells the platelet-aggregating abilities and hematogenous metastasis phenotypes. From the 8F11 mAb recognition epitopes, podoplanin is found to contain tandemly repeated, highly conserved motifs, designated platelet aggregation-stimulating (PLAG) domains. Series of analyses using the cells expressing the mutants and the established neutralizing anti-podoplanin mAbs uncovered that both PLAG3 and PLAG4 domains are associated with the CLEC-2 binding. The neutralizing mAbs targeting PLAG3 or PLAG4 could suppress podoplanin-induced platelet aggregation and hematogenous metastasis through inhibiting the podoplanin-CLEC-2 binding. Therefore, these domains are certainly functional in podoplanin-mediated metastasis through its platelet-aggregating activity. This review summarizes the platelet functions in metastasis formation, the role of platelet aggregation-inducing factor podoplanin in pathological and physiological situations, and the possibility to develop podoplanin-targeting drugs in the future.
-
Inoue, Yoshinori; Sugano, Norihide; Jibiki, Masatoshi; Kudo, Toshifumi; Iwai, Takehisa
2008-01-01
Problems associated with prosthetic graft replacement are stenosis at the anastomosis site and thrombus formation on the inner surface. Cilostazol is known to have antiplatelet activity and inhibit vascular smooth muscle cell proliferation and neointima thickening. A cilostazol derivative, (-)-6-[3-[3-cyclopropyl-3-[(1R,2R)-2-hydroxycyclohexyl]ureido]-propoxy]-2-(1H)-quinolinone (K-134), has more potent anti-platelet activity and anti-neointimal thickening activity than cilostazol in the in-vitro platelet aggregation and in-vivo anti-hyperplastic activity assay. The aim of this study was to investigate effects of cilostazol and K-134 on thrombus formation and neointimal thickening at the site of prosthetic graft replacement. Beagle dogs underwent infrarenal abdominal aortic resection with straight Dacron graft replacement, which were allocated to the control, cilostazol, and K-134 groups. Two dogs were dead without confirming the cause of death. After 6 months, all dogs were necropsied. All prosthetic grafts were patent in each group. Ratios of red thrombus to prosthetic graft area were 0.3+/-6.4%, and 3.3+/-4.5% in the cilostazol and K-134 groups, respectively, which were significant different from that in the control group (24.4+/-16.8%). However, no clear difference was seen among the 3 groups with respect to neointimal thickness (control group, 0.70+/-0.13 mm; cilostazol group, 0.59+/-0.14 mm; K-134 group, 0.67+/-0.14 mm). Cilostazol and K-134 significantly inhibited thrombus formation on the inner surface of the prosthetic graft at 6 months after graft replacement. Neointimal thickening on the inner surface was slight even in control-group animals, and the effects of cilostazol and K-134 on such thickening were unclear.
-
Novel Percutaneous Radiofrequency Ablation of Portal Vein Tumor Thrombus: Safety and Feasibility
Energy Technology Data Exchange (ETDEWEB)
Mizandari, Malkhaz [High Technology Medical Center, Tbilisi State Medical University (Georgia); Ao, Guokun [The 309 Hospital of People' s Liberation Army, Department on Oncology (China); Zhang Yaojun; Feng Xi [Imperial College London, Department of Surgery and Cancer (United Kingdom); Shen Qiang [The First Minimally Invasive Department of Eastern Hepatobiliary Surgery Hospital (China); Chen Minshan [Cancer Centre of Sun Yat-Sen University, Department of Hepatobiliary Surgery (China); Lau, Wan Yee [Chinese University of Hong Kong, Department of Surgery, Faculty of Medicine (Hong Kong); Nicholls, Joanna; Jiao Long; Habib, Nagy, E-mail: nagy.habib@imperial.ac.uk [Imperial College London, Department of Surgery and Cancer (United Kingdom)
2013-02-15
We report our experience of the safety of partial recanalization of the portal vein using a novel endovascular radiofrequency (RF) catheter for portal vein tumor thrombosis. Six patients with liver cancer and tumor thrombus in the portal vein underwent percutaneous intravascular radiofrequency ablation (RFA) using an endovascular bipolar RF device. A 0.035-inch guidewire was introduced into a tributary of the portal vein and through which a 5G guide catheter was introduced into the main portal vein. After manipulation of the guide catheter over the thrombus under digital subtraction angiography, the endovascular RF device was inserted and activated around the thrombus. There were no observed technique specific complications, such as hemorrhage, vessel perforation, or infection. Post-RFA portography showed partial recanalization of portal vein. RFA of portal vein tumor thrombus in patients with hepatocellular carcinoma is technically feasible and warrants further investigation to assess efficacy compared with current recanalization techniques.
-
A thrombus in transit through a patent foramen ovale.
Ibebuogu, Uzoma N; Khouzam, Rami N; Sharma, Gyanendra; Thornton, John W; Robati, Roshanak; Silverman, David
2014-10-01
Patent foramen ovale (PFO) is a congenital heart defect that may first be diagnosed in adulthood and has a prevalence of 25% to 30%. Although many patients with PFO are asymptomatic and do not require treatment, paradoxical embolism can cause stroke or myocardial infarction. The authors report an unusual case of PFO with a transversing thrombus in an 80-year-old man. The patient's initial presentation appeared clinically as acute coronary syndrome, but he was subsequently diagnosed with a massive thrombus in transit via a PFO and pulmonary embolus leading to right-sided heart failure.
-
Blood platelet kinetics and platelet transfusion.
Aster, Richard H
2013-11-01
The discovery of citrate anticoagulant in the 1920s and the development of plastic packs for blood collection in the 1960s laid the groundwork for platelet transfusion therapy on a scale not previously possible. A major limitation, however, was the finding that platelet concentrates prepared from blood anticoagulated with citrate were unsuitable for transfusion because of platelet clumping. We found that this could be prevented by simply reducing the pH of platelet-rich plasma to about 6.5 prior to centrifugation. We used this approach to characterize platelet kinetics and sites of platelet sequestration in normal and pathologic states and to define the influence of variables such as anticoagulant and ABO incompatibility on post-transfusion platelet recovery. The "acidification" approach enabled much wider use of platelet transfusion therapy until alternative means of producing concentrates suitable for transfusion became available.
-
New gene functions in megakaryopoiesis and platelet formation
Gieger, Christian; Radhakrishnan, Aparna; Cvejic, Ana; Tang, Weihong; Porcu, Eleonora; Pistis, Giorgio; Serbanovic-Canic, Jovana; Elling, Ulrich; Goodall, Alison H.; Labrune, Yann; Lopez, Lorna M.; Mägi, Reedik; Meacham, Stuart; Okada, Yukinori; Pirastu, Nicola; Sorice, Rossella; Teumer, Alexander; Voss, Katrin; Zhang, Weihua; Ramirez-Solis, Ramiro; Bis, Joshua C.; Ellinghaus, David; Gögele, Martin; Hottenga, Jouke-Jan; Langenberg, Claudia; Kovacs, Peter; O'Reilly, Paul F.; Shin, So-Youn; Esko, Tõnu; Hartiala, Jaana; Kanoni, Stavroula; Murgia, Federico; Parsa, Afshin; Stephens, Jonathan; van der Harst, Pim; van der Schoot, C. Ellen; Allayee, Hooman; Attwood, Antony; Balkau, Beverley; Bastardot, François; Basu, Saonli; Baumeister, Sebastian E.; Biino, Ginevra; Bomba, Lorenzo; Bonnefond, Amélie; Cambien, François; Chambers, John C.; Cucca, Francesco; D'Adamo, Pio; Davies, Gail; de Boer, Rudolf A.; de Geus, Eco J. C.; Döring, Angela; Elliott, Paul; Erdmann, Jeanette; Evans, David M.; Falchi, Mario; Feng, Wei; Folsom, Aaron R.; Frazer, Ian H.; Gibson, Quince D.; Glazer, Nicole L.; Hammond, Chris; Hartikainen, Anna-Liisa; Heckbert, Susan R.; Hengstenberg, Christian; Hersch, Micha; Illig, Thomas; Loos, Ruth J. F.; Jolley, Jennifer; Khaw, Kay Tee; Kühnel, Brigitte; Kyrtsonis, Marie-Christine; Lagou, Vasiliki; Lloyd-Jones, Heather; Lumley, Thomas; Mangino, Massimo; Maschio, Andrea; Mateo Leach, Irene; McKnight, Barbara; Memari, Yasin; Mitchell, Braxton D.; Montgomery, Grant W.; Nakamura, Yusuke; Nauck, Matthias; Navis, Gerjan; Nöthlings, Ute; Nolte, Ilja M.; Porteous, David J.; Pouta, Anneli; Pramstaller, Peter P.; Pullat, Janne; Ring, Susan M.; Rotter, Jerome I.; Ruggiero, Daniela; Ruokonen, Aimo; Sala, Cinzia; Samani, Nilesh J.; Sambrook, Jennifer; Schlessinger, David; Schreiber, Stefan; Schunkert, Heribert; Scott, James; Smith, Nicholas L.; Snieder, Harold; Starr, John M.; Stumvoll, Michael; Takahashi, Atsushi; Tang, W. H. Wilson; Taylor, Kent; Tenesa, Albert; Lay Thein, Swee; Tönjes, Anke; Uda, Manuela; Ulivi, Sheila; van Veldhuisen, Dirk J.; Visscher, Peter M.; Völker, Uwe; Wichmann, H.-Erich; Wiggins, Kerri L.; Willemsen, Gonneke; Yang, Tsun-Po; Hua Zhao, Jing; Zitting, Paavo; Bradley, John R.; Dedoussis, George V.; Gasparini, Paolo; Hazen, Stanley L.; Metspalu, Andres; Pirastu, Mario; Shuldiner, Alan R.; Joost van Pelt, L.; Zwaginga, Jaap-Jan; Boomsma, Dorret I.; Deary, Ian J.; Franke, Andre; Froguel, Philippe; Ganesh, Santhi K.; Jarvelin, Marjo-Riitta; Martin, Nicholas G.; Meisinger, Christa; Psaty, Bruce M.; Spector, Timothy D.; Wareham, Nicholas J.; Akkerman, Jan-Willem N.; Ciullo, Marina; Deloukas, Panos; Greinacher, Andreas; Jupe, Steve; Kamatani, Naoyuki; Khadake, Jyoti; Kooner, Jaspal S.; Penninger, Josef; Prokopenko, Inga; Stemple, Derek; Toniolo, Daniela; Wernisch, Lorenz; Sanna, Serena; Hicks, Andrew A.; Rendon, Augusto; Ferreira, Manuel A.; Ouwehand, Willem H.; Soranzo, Nicole
2011-01-01
Platelets are the second most abundant cell type in blood and are essential for maintaining haemostasis. Their count and volume are tightly controlled within narrow physiological ranges, but there is only limited understanding of the molecular processes controlling both traits. Here we carried out a
-
Chabasse, Christine; Siefert, Suzanne A; Chaudry, Mohammed; Hoofnagle, Mark H; Lal, Brajesh K; Sarkar, Rajabrata
2015-01-01
We examined the role of thrombus recanalization and ongoing blood flow in the process of thrombus resolution by comparing two murine in vivo models of deep venous thrombosis. In CD1 mice, we performed surgical inferior vena cava ligation (stasis thrombosis), stenosis (thrombosis with recanalization), or sham procedure. We analyzed thrombus weight over time as a measure of thrombus resolution and quantified the messenger RNA and protein levels of membrane-type matrix metalloproteinases (MT-MMPs) as well as effectors of the plasmin complex at days 4, 8, and 12 after surgery. Despite similar initial thrombus size, the presence of ongoing blood flow (stenosis model) was associated with a 45.91% subsequent improvement in thrombus resolution at day 8 and 12.57% at day 12 compared with stasis thrombosis (ligation model). Immunoblot and real-time polymerase chain reaction analysis demonstrated a difference in MMP-2 and MMP-9 activity at day 8 between the two models (P = .03 and P = .006, respectively) as well as a difference in MT2-MMP gene expression at day 8 (P = .044) and day 12 (P = .03) and MT1-MMP protein expression at day 4 (P = .021). Histologic analyses revealed distinct areas of recanalization in the thrombi of the stenosis model compared with the ligation model as well as the recruitment of inflammatory cells, especially macrophages, and a focal pattern of localized expression of MT1-MMP and MT3-MMP proteins surrounding the areas of recanalization in the stenosis model. Recanalization and ongoing blood flow accelerate deep venous thrombus resolution in vivo and are associated with distinct patterns of MT1-MMP and MT3-MMP expression and macrophage localization in areas of intrathrombus recanalization. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.
-
Trouillas, Marina; Prat, Marie; Doucet, Christelle; Ernou, Isabelle; Laplace-Builhé, Corinne; Blancard, Patrick Saint; Holy, Xavier; Lataillade, Jean-Jacques
2013-01-04
This study investigated the promising effect of a new Platelet Glue obtained from Cryoprecipitation of Apheresis Platelet products (PGCAP) used in combination with Mesenchymal Stromal Cells (MSC) loaded on ceramic biomaterials to provide novel strategies enhancing bone repair. PGCAP growth factor content was analyzed by ELISA and compared to other platelet and plasma-derived products. MSC loaded on biomaterials (65% hydroxyapatite/35% beta-TCP or 100% beta-TCP) were embedded in PGCAP and grown in presence or not of osteogenic induction medium for 21 days. Biomaterials were then implanted subcutaneously in immunodeficient mice for 28 days. Effect of PGCAP on MSC was evaluated in vitro by proliferation and osteoblastic gene expression analysis and in vivo by histology and immunohistochemistry. We showed that PGCAP, compared to other platelet-derived products, allowed concentrating large amount of growth factors and cytokines which promoted MSC and osteoprogenitor proliferation. Next, we found that PGCAP improves the proliferation of MSC and osteogenic-induced MSC. Furthermore, we demonstrated that PGCAP up-regulates the mRNA expression of osteogenic markers (Collagen type I, Osteonectin, Osteopontin and Runx2). In vivo, type I collagen expressed in ectopic bone-like tissue was highly enhanced in biomaterials embedded in PGCAP in the absence of osteogenic pre-induction. Better results were obtained with 65% hydroxyapatite/35% beta-TCP biomaterials as compared to 100% beta-TCP. We have demonstrated that PGCAP is able to enhance in vitro MSC proliferation, osteoblastic differentiation and in vivo bone formation in the absence of osteogenic pre-induction. This clinically adaptable platelet glue could be of interest for improving bone repair.
-
Incremental value of contrast echocardiography in the evaluation of a cardiac thrombus.
Po, Jose Ricardo F; Tong, Matthew S; Grove, Erica L; Biederman, Robert W W
2017-02-01
A 52-year-old man presented with altered mental status and report of prior complaint of chest pain. On electrocardiography, anterolateral ST-segment elevations with Q-waves in the septal leads were seen. Initial echocardiography images demonstrated a thickened anteroseptum. Further imaging showed the presence of a well-attached laminated apical thrombus. Contrast echocardiography images showed that the thrombus had minimal attachment to the endocardial surface. CT head subsequently showed the presence of acute stroke. The case demonstrates the additional value of contrast echocardiography in the evaluation of cardiac masses despite the certainty in the diagnosis of a thrombus. © 2017, Wiley Periodicals, Inc.
-
Renal angiomyolipoma with inferior vena caval thrombus in a 32-year-old male
Directory of Open Access Journals (Sweden)
Matthew W Christian
2009-01-01
Full Text Available Renal angiomyolipoma (AML rarely presents with evidence of extension into the renal vein, inferior vena cava (IVC or atrium. We report a case of a renal AML with a tumor thrombus to the IVC in a 32-year-old male. The patient subsequently underwent a right radical nephrectomy with IVC tumor thrombectomy. To our knowledge, there are four published cases of renal AML presenting with tumor thrombus in males. This case report describes the management of the youngest male ever to develop a renal AML with IVC tumor thrombus.
-
Platelet size and age determine platelet function independently
International Nuclear Information System (INIS)
Thompson, C.B.; Jakubowski, J.A.; Quinn, P.G.; Deykin, D.; Valeri, C.R.
1984-01-01
A study was undertaken to examine the interaction of platelet size and age in determining in vitro platelet function. Baboon megakaryocytes were labeled in vivo by the injection of 75Se-methionine. Blood was collected when the label was predominantly associated with younger platelets (day 2) and with older platelets (day 9). Size-dependent platelet subpopulations were prepared on both days by counterflow centrifugation. The reactivity of each platelet subpopulation was determined on both days by measuring thrombin-induced aggregation. Platelets were fixed after partial aggregation had occurred by the addition of EDTA/formalin. After removal of the aggregated platelets by differential centrifugation, the supernatant medium was assayed for remaining platelets and 75Se radioactivity. Comparing day 2 and day 9, no significant difference was seen in the rate of aggregation of a given subpopulation. However, aggregation was more rapid in the larger platelet fractions than in the smaller ones on both days. A greater percentage of the 75Se radioactivity appeared in the platelet aggregates on day 2 than on day 9. This effect was independent of platelet size, as it occurred to a similar extent in the unfractionated platelets and in each of the size-dependent platelet subpopulations. The data indicate that young platelets are more active than older platelets. This study demonstrates that size and age are both determinants of platelet function, but by independent mechanisms
-
Covered stent to exclude intravascular thrombus.
Liistro, Francesco; Stankovic, Goran; Di Mario, Carlo; Montorfano, Matteo; Briguori, Carlo; Colombo, Antonio
2002-04-01
To describe the utility of stent-graft implantation to avoid distal embolization from a large thrombus-containing lesion. A 67-year-old man was evaluated for recent onset of disabling left leg claudication. Angiography disclosed a mobile lobular mass occluding the left common iliac artery; irregular staining suggested an atherothrombotic lesion. Through a percutaneous ipsilateral access and an 8-F sheath, a balloon-expandable Jostent peripheral stent-graft was positioned with the distal edge immediately proximal to the internal iliac artery ostium. A prominent "waist" at the center of the balloon confirmed entrapment of the thrombotic mass. Completion angiography showed an optimal result with no residual stenosis or evidence of distal embolization. At 6-month follow-up, the patient was asymptomatic with angiographically documented luminal patency and no evidence of in-stent stenosis. Stent-graft implantation appears a viable treatment alternative for thrombus-containing lesions, particularly when the thrombotic material is localized or is in a large vessel.
-
Added value of multiphase CTA imaging for thrombus perviousness assessment
Energy Technology Data Exchange (ETDEWEB)
Santos, E.M.M. [Academic Medical Center, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Erasmus Medical Center, Department of Medical Informatics, Rotterdam (Netherlands); D' Esterre, C.D.; Najm, M.; Goyal, M.; Demchuk, A.M.; Menon, B.K. [University of Calgary, Departments of Neurosciences, Radiology and Community Health Sciences, Calgary (Canada); Treurniet, K.M.; Majoie, C.B. [Academic Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Niessen, W.J. [Erasmus Medical Center, Department of Medical Informatics, Rotterdam (Netherlands); Delft University of Technology, Faculty of Applied Sciences, Delft (Netherlands); Marquering, H.A. [Academic Medical Center, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Academic Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Mandzia, Jennifer; Fainardi, Enrico; Rubiera, Marta; Khaw, Alexander V.; Zini, Andrea; Shankar, JJ.; Collaboration: PRove-IT investigators
2018-01-15
Thrombus perviousness has been associated with favorable functional outcome in acute ischemic stroke (AIS) patients. Measuring thrombus perviousness on CTA may be suboptimal due to potential delay in contrast agent arrival in occluded arteries at the moment of imaging. Dynamic sequences acquired over time can potentially overcome this issue. We investigate if dynamic CTA has added value in assessing thrombus perviousness. Prospectively collected image data of AIS patients with proven occlusion of the anterior or posterior circulation with thin-slice multi-phase CTA (MCTA) and non-contrast CT were co-registered (n = 221). Thrombus attenuation increase (TAI; a perviousness measure) was measured for the arterial, venous, and delayed phase of the MCTA and time-invariant CTAs (TiCTA). Associations with favorable clinical outcome (90-day mRS ≤ 2) were assessed using univariate and multivariable regressions and calculating areas under receiver operating curves (AUC). TAI determined from the arterial phase CTA was superior in the association with favorable outcome with OR = 1.21 per 10 HU increase (95%CI 1.04-1.41, AUC 0.62, p = 0.014) compared to any other phase (venous 1.14(95%CI 1.01-1.30, AUC 0.58, p = 0.033), delayed 1.046(95%CI 0.919-1.19, AUC 0.53, p = 0.50)), and TiCTA 1.15(95%CI 1.02-1.30, AUC 0.60, p = 0.022). In the multivariable model, only TAI on arterial phase was significantly associated with favorable outcome (aOR 1.59, 95%CI 1.04-2.43, p = 0.032). Association between TAI with functional outcome was optimal on arterial-phase CTA such that dynamic CTA imaging has no additional benefits in current thrombus perviousness assessment, thereby suggesting that the delay of contrast arrival at the clot is a key variable for patient functional outcome. (orig.)
-
Successful Treatment of Free-Floating Right Ventricular Thrombus with Acute Pulmonary Embolism
Directory of Open Access Journals (Sweden)
Sanjay Singhal
2015-01-01
Full Text Available Acute pulmonary embolism with floating right intra-ventricular thrombus is a rare phenomena associated with poor prognosis. Here, we are presenting a case of 35-year-young male with no co-morbid illness diagnosed to have right ventricular thrombus with bilateral pulmonary embolism, which was managed successfully with thrombolytic therapy.
-
LENUS (Irish Health Repository)
Lobo, R
2015-11-01
Dabigatran etexilate is licensed for use in prevention of deep venous thromboembolism and in prevention of stroke and systemic embolism in nonvalvular atrial fibrillation (AF). It has also been used in patients for other indications as a substitute for warfarin therapy because it requires no monitoring; one group being patients undergoing radiofrequency (RF), ablation for AF, although there have been no consensus guidelines with regards to dosage and timing of dose. We report the case of a patient with documentary evidence of left atrial appendage (LAA) thrombus formation and neurological sequelae post-RF ablation despite being on dabigatran. This case highlights the concern that periprocedural dabigatran may not provide adequate protection from development of LAA thrombus and that a standardised protocol will need to be developed and undergo large multicentre trials before dabigatran can be safely used for patients undergoing RF-ablation.
-
White, Nathan J; Martin, Erika J; Brophy, Donald F; Ward, Kevin R
2011-07-01
A significant proportion of severely injured patients develop early coagulopathy, characterized by abnormal clot formation, which impairs resuscitation and increases mortality. We have previously demonstrated an isolated decrease in clot strength by thrombelastography in a swine model of nonresuscitated traumatic shock. In order to more closely examine platelet-fibrin interactions in this setting, we define the observed decrease in clot strength in terms of platelet-induced clot contraction and clot elastic modulus using the Hemostasis Analysis System (HAS) (Hemodyne Inc., Richmond, Virginia, USA). Whole blood was sampled for HAS measurements, metabolic measurements, cell counts, and fibrinogen concentration at baseline prior to injury and again at a predetermined level of traumatic shock defined by oxygen debt. Male swine (N=17) received femur fracture and controlled arterial hemorrhage to achieve an oxygen debt of 80 ml/kg. Platelet counts were unchanged, but fibrinogen concentration was reduced significantly during shock (167.6 vs. 66.7 mg/dl, P=0.0007). Platelet contractile force generated during clot formation did not change during shock (11.7 vs. 10.4 kdynes, P=0.41), but clot elastic modulus was dynamically altered, resulting in a lower final value (22.9 vs. 17.3 kdynes/cm, Pshock, platelet function was preserved, whereas terminal clot elastic modulus was reduced during shock in a manner most consistent with early changes in the mechanical properties of the developing fibrin fiber network.
-
Niacin and biosynthesis of PGD₂by platelet COX-1 in mice and humans.
Song, Wen-Liang; Stubbe, Jane; Ricciotti, Emanuela; Alamuddin, Naji; Ibrahim, Salam; Crichton, Irene; Prempeh, Maxwell; Lawson, John A; Wilensky, Robert L; Rasmussen, Lars Melholt; Puré, Ellen; FitzGerald, Garret A
2012-04-01
The clinical use of niacin to treat dyslipidemic conditions is limited by noxious side effects, most commonly facial flushing. In mice, niacin-induced flushing results from COX-1-dependent formation of PGD₂ and PGE₂ followed by COX-2-dependent production of PGE₂. Consistent with this, niacin-induced flushing in humans is attenuated when niacin is combined with an antagonist of the PGD₂ receptor DP1. NSAID-mediated suppression of COX-2-derived PGI₂ has negative cardiovascular consequences, yet little is known about the cardiovascular biology of PGD₂. Here, we show that PGD₂ biosynthesis is augmented during platelet activation in humans and, although vascular expression of DP1 is conserved between humans and mice, platelet DP1 is not present in mice. Despite this, DP1 deletion in mice augmented aneurysm formation and the hypertensive response to Ang II and accelerated atherogenesis and thrombogenesis. Furthermore, COX inhibitors in humans, as well as platelet depletion, COX-1 knockdown, and COX-2 deletion in mice, revealed that niacin evoked platelet COX-1-derived PGD₂ biosynthesis. Finally, ADP-induced spreading on fibrinogen was augmented by niacin in washed human platelets, coincident with increased thromboxane (Tx) formation. However, in platelet-rich plasma, where formation of both Tx and PGD₂ was increased, spreading was not as pronounced and was inhibited by DP1 activation. Thus, PGD₂, like PGI₂, may function as a homeostatic response to thrombogenic and hypertensive stimuli and may have particular relevance as a constraint on platelets during niacin therapy.
-
Evaluation of thrombelastographic platelet-mapping in healthy cats.
Blois, Shauna L; Banerjee, Amrita; Wood, R Darren
2012-06-01
Thrombelastography (TEG) permits analysis of clot formation but it is not specific for platelet activity. TEG PlateletMapping (TEG-PM) is a modification of TEG that uses adenosine diphosphate (ADP) and arachidonic acid (AA) as platelet agonists to define the contribution of platelets to clot formation. The objectives of this study were to determine values for TEG-PM in healthy cats and the interassay variation of TEG-PM. TEG-PM analysis was performed on blood specimens collected from 12 healthy cats and was repeated using a second blood specimen collected 2 hours later. Maximum amplitudes generated by thrombin (MA(thrombin)), fibrin (MA(fibrin)), ADP-stimulated platelet activity (MA(ADP)), and AA-stimulated platelet activity (MA(AA)) were recorded. Mean ± SD for MA(thrombin) was 51.1 ± 8.5 mm, for MA(fibrin) was 32.3 ± 17.7 mm, for MA(ADP) was 32.3 ± 15.0 mm, and for MA(AA) was 24.5 ± 12.2 mm. Mean MA(ADP) and MA(fibrin) were not significantly different, whereas mean MA(AA) was significantly lower than mean MA(fibrin). Results from the first and second specimens were not significantly different. Correlation between the first and second specimens was moderate for MA(thrombin), MA(fibrin), and MA(ADP), but was poor for MA(AA). A high degree of variability (coefficient of variation 47.7-60.0%) was observed for MA(fibrin), MA(ADP), and MA(AA). As MA(ADP) and MA(AA) (AA) were the same as or lower than MA(fibrin), a valid baseline to determine platelet-stimulated clot formation could not be established. Considerable interassay variation and wide intervals for MA(fibrin), MA(ADP), and MA(AA) values in this study indicate that TEG-PM should be used cautiously in feline patients. Several preanalytical factors should be examined in further detail. © 2012 American Society for Veterinary Clinical Pathology.
-
Splenectomy Is Modifying the Vascular Remodeling of Thrombosis
Frey, Maria K.; Alias, Sherin; Winter, Max P.; Redwan, Bassam; Stübiger, Gerald; Panzenboeck, Adelheid; Alimohammadi, Arman; Bonderman, Diana; Jakowitsch, Johannes; Bergmeister, Helga; Bochkov, Valery; Preissner, Klaus T.; Lang, Irene M.
2014-01-01
Background Splenectomy is a clinical risk factor for complicated thrombosis. We hypothesized that the loss of the mechanical filtering function of the spleen may enrich for thrombogenic phospholipids in the circulation, thereby affecting the vascular remodeling of thrombosis. Methods and Results We investigated the effects of splenectomy both in chronic thromboembolic pulmonary hypertension (CTEPH), a human model disease for thrombus nonresolution, and in a mouse model of stagnant flow venous thrombosis mimicking deep vein thrombosis. Surgically excised thrombi from rare cases of CTEPH patients who had undergone previous splenectomy were enriched for anionic phospholipids like phosphatidylserine. Similar to human thrombi, phosphatidylserine accumulated in thrombi after splenectomy in the mouse model. A postsplenectomy state was associated with larger and more persistent thrombi. Higher counts of procoagulant platelet microparticles and increased leukocyte–platelet aggregates were observed in mice after splenectomy. Histological inspection revealed a decreased number of thrombus vessels. Phosphatidylserine‐enriched phospholipids specifically inhibited endothelial proliferation and sprouting. Conclusions After splenectomy, an increase in circulating microparticles and negatively charged phospholipids is enhanced by experimental thrombus induction. The initial increase in thrombus volume after splenectomy is due to platelet activation, and the subsequent delay of thrombus resolution is due to inhibition of thrombus angiogenesis. The data illustrate a potential mechanism of disease in CTEPH. PMID:24584745
-
Platelet granule exocytosis: A comparison with chromaffin cells
Directory of Open Access Journals (Sweden)
Jennifer eFitch-Tewfik
2013-06-01
Full Text Available The rapid secretion of bioactive amines from chromaffin cells constitutes an important component of the fight or flight response of mammals to stress. Platelets respond to stresses within the vasculature by rapidly secreting cargo at sites of injury, inflammation, or infection. Although chromaffin cells derive from the neural crest and platelets from bone marrow megakaryocytes, both have evolved a heterogeneous assemblage of granule types and a mechanism for efficient release. This article will provide an overview of granule formation and exocytosis in platelets with an emphasis on areas in which the study of chromaffin cells has influenced that of platelets and on similarities between the two secretory systems. Commonalities include the use of transporters to concentrate bioactive amines and other cargos into granules, the role of cytoskeletal remodeling in granule exocytosis, and the use of granules to provide membrane for cytoplasmic projections. The SNAREs and SNARE accessory proteins used by each cell type will also be considered. Finally, we will discuss the newly appreciated role of dynamin family proteins in regulated fusion pore formation. This evaluation of the comparative cell biology of regulated exocytosis in platelets and chromaffin cells demonstrates a convergence of mechanisms between two disparate cell types both tasked with responding rapidly to physiological stimuli.
-
Storage of platelets: effects associated with high platelet content in platelet storage containers.
Gulliksson, Hans; Sandgren, Per; Sjödin, Agneta; Hultenby, Kjell
2012-04-01
A major problem associated with platelet storage containers is that some platelet units show a dramatic fall in pH, especially above certain platelet contents. The aim of this study was a detailed investigation of the different in vitro effects occurring when the maximum storage capacity of a platelet container is exceeded as compared to normal storage. Buffy coats were combined in large-volume containers to create primary pools to be split into two equal aliquots for the preparation of platelets (450-520×10(9) platelets/unit) in SSP+ for 7-day storage in two containers (test and reference) with different platelet storage capacity (n=8). Exceeding the maximum storage capacity of the test platelet storage container resulted in immediate negative effects on platelet metabolism and energy supply, but also delayed effects on platelet function, activation and disintegration. Our study gives a very clear indication of the effects in different phases associated with exceeding the maximum storage capacity of platelet containers but throw little additional light on the mechanism initiating those negative effects. The problem appears to be complex and further studies in different media using different storage containers will be needed to understand the mechanisms involved.
-
Dong, Dian-ning; Wu, Xue-jun; Zhang, Shi-yi; Zhong, Zhen-yue; Jin, Xing
2013-06-04
To explore the clinical profiles of patients with lower extremity deep venous thrombosis (DVT) complicated with inferior vena cava (IVC) thrombus and summarize their clinical diagnostic and therapeutic experiences. The clinical characteristics, diagnosis and treatment of 20 hospitalized patients with DVT complicated with inferior vena cava thrombus were analyzed retrospectively. All of them were of proximal DVT. There were phlegmasia cerulea dolens (n = 3), pulmonary embolism (n = 3) and completely occlusion of IVC (n = 5). Clinical manifestations were severe. Retrievable inferior vena cava filter (IVCF) was implanted for 17 cases. Catheter-directed thrombolysis (CDT) through ipsilateral popliteal vein was applied for 7 cases and systemic thrombolysis therapy for 8 cases. The effective rate of thrombolysis for fresh IVC thrombus was 100%. Among 5 cases with Cockett Syndrome, 3 cases underwent balloon dilatation angioplasty and endovascular stenting of iliac vein. And 17 IVCFs were retrieved successfully within 3 weeks. IVC thrombus disappeared completely in 15 cases. Systemic or local thrombolysis with protective IVCF is a safe and effective therapy for nonocclusive IVC thrombus in DVT. And CDT is recommended for symptomatic occlusive IVC thrombus.
-
Aziz, F; Comerota, A J
2012-08-01
Iliofemoral deep venous thrombosis (IFDVT) is an independent risk factor for recurrent DVT. It has been observed that recurrent DVT correlates with residual thrombus. This study evaluates whether risk of recurrence is related to the amount of residual thrombus following catheter-directed thrombolysis (CDT) for IFDVT. Patients who underwent CDT for IFDVT had their degree of lysis quantified by a reader blind to the patients' long-term clinical outcome. Patients were classified into two groups, ≥50% and thrombus. Recurrence was defined as a symptomatic presentation with image verification of new or additional thrombus. A total of 75 patients underwent CDT for IFDVT. Median follow-up was 35.9 months. Sixty-eight patients (91%) had no evidence of recurrence and seven (9%) developed recurrence. Of the patients who had ≥50% (mean 80%) residual thrombus, 50% (4/8) experienced recurrence, but in those with thrombus, only 5% (3/67) had recurrent DVT (P = 0.0014). The burden of residual thrombus at completion of CDT correlates with the risk of DVT recurrence. Patients having CDT for IFDVT had a lower risk of recurrence than expected. Successful clearing of acute clot in IFDVT patients significantly reduces the recurrence risk compared to patients with a large residual thrombus burden. Copyright © 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.
-
Hu, Guang-quan; Liu, Jian; Yang, Li; Yan, Yi; Wu, Jue-fei; Xie, Jia-jia; Cai, Jing-jing; Ji, Li-jing; Bin, Jian-ping
2010-03-01
To assess the binding ability of microbubbles targeted to alphavbeta3-integrin (MBp) for thrombus-targeted contrast-enhanced ultrasound. Targeted microbubbles were prepared by conjugating the monoclonal antibody against alphavbeta3-integrin to lipid shell of the microbubble via the avidin-biotin bridges. Equivalent isotype control microbubbles (MB) or targeted ultrasound microbubbles (MBp) were randomly added into the flow chamber. After a 30-min incubation with the thrombus fixed in an agarose flow chamber model, the thrombus was washed with a continuous flow of PBS solution (15 cm/s) for 2, 4, 6, 8 and 10 min, followed by thrombus imaging using contrast-enhanced ultrasound and measurement of the video intensity (VI) values of the images. The VI of the thrombus in MBp group was reduced by 28%-66%, while that in control MB group was decreased by 87%-94%, and the VI values of the thrombus group were significantly greater in former group at each of the time points (Pevaluation of the thrombus-binding capability of the targeted microbubble (MBp) by simulating the shear stress in vivo can be helpful for predicting the in vivo effects of ultrasonic molecular imaging using MBp.
-
Suzuki-Inoue, K; Osada, M; Ozaki, Y
2017-02-01
A platelet activation receptor, C-type lectin-like receptor 2 (CLEC-2), has been identified as a receptor for a platelet-activating snake venom, rhodocytin. CLEC-2 protein is highly expressed in platelets/megakaryocytes, and at lower levels in liver Kupffer cells. Recently, podoplanin has been revealed as an endogenous ligand for CLEC-2. Podoplanin is expressed in certain types of tumor cells, fibroblastic reticular cells (FRCs) in lymph nodes, kidney podocytes, and lymphatic endothelial cells, but not in vascular endothelial cells. CLEC-2 in platelets cannot have access to podoplanin under normal conditions, but they interact with each other under pathologic conditions or during developmental stages, and play various pathophysiologic roles. CLEC-2 facilitates hematogenous metastasis of podoplanin-expressing tumors. During development, the interaction between CLEC-2 and podoplanin in lymphatic endothelial cells or neuroepithelial cells facilitates blood-lymphatic vessel separation and cerebrovascular patterning and integrity, respectively. In adulthood, platelet CLEC-2 binding to FRCs is crucial for maintenance of the integrity of high endothelial venules in lymph nodes. Podoplanin-expressing FRC-like cells have recently been identified in the bone marrow, and facilitate megakaryocyte proliferation and proplatelet formation by binding to megakaryocyte CLEC-2. Podoplanin is inducibly expressed in liver monocytes and keratinocytes during Salmonella infection and wound healing, and regulates thrombus formation in the liver and controlled wound healing, respectively. By binding to unknown ligands, platelet CLEC-2 regulates the maintenance of vascular integrity during inflammation, thrombus stability under flow, and maintenance of quiescence of hematopoietic stem cells. Podoplanin is expressed in various cells, and additional roles of the CLEC-2-podoplanin interaction will be revealed in the future. © 2016 International Society on Thrombosis and Haemostasis.
-
Ischemic Stroke: What Does the Histological Composition Tell Us About the Origin of the Thrombus?
Sporns, Peter B; Hanning, Uta; Schwindt, Wolfram; Velasco, Aglaé; Minnerup, Jens; Zoubi, Tarek; Heindel, Walter; Jeibmann, Astrid; Niederstadt, Thomas Ulrich
2017-08-01
The introduction of stent retrievers allows for a complete extraction and histological analysis of human thrombi. Ischemic stroke is a major health issue, and differentiation of underlying causes is highly relevant to prevent recurrent stroke. Therefore, histopathologic analysis of the embolic clots after removal may provide valuable information about underlying pathologies. This study analyzes histological clot composition and aims to identify specific patterns that might help to distinguish causes of ischemic stroke. Patients with occlusion of the carotid-T or middle cerebral artery who underwent thrombectomy at our university medical center between December 2013 and February 2016 were included. Samples were histologically analyzed (hematoxylin and eosin, Elastica van Gieson, and Prussian blue), additionally immunohistochemistry for CD3, CD20, and CD68/KiM1P was performed. These data, along with additional clinical and interventional parameters, were compared for different stroke subtypes, as defined by the TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification. One hundred eighty-seven patients were included, of these, in 77 patients, cardioembolic; in 46 patients, noncardioembolic; and in 64 patients, cryptogenic pathogenesis was determined. Cardioembolic thrombi had higher proportions of fibrin/platelets ( P =0.027), less erythrocytes ( P =0.005), and more leucocytes ( P =0.026) than noncardioembolic thrombi. We observed a strong overlap of cryptogenic strokes and cardioembolic strokes concerning thrombus histology. The immunohistochemical parameters CD3, CD20, and CD68/KiM1P showed no statistically noticeable differences between stroke subtypes. Histological thrombus features vary significantly according to the underlying cause and may help to differentiate between cardioembolic and noncardioembolic stroke. In addition, our study supports the hypothesis that most cryptogenic strokes have a cardioembolic cause. © 2017 American Heart Association
-
Slow flow and mural thrombus in aortic diseases: Spin-echo MR findings and their differentiation
International Nuclear Information System (INIS)
Chung, Jin Wook; Park, Jae Hyung; Han, Man Chung
1993-01-01
In order to evaluate the ability of spin-echo MR imaging to differentiate slow flow from mural thrombus in aortic diseases, we reviewed the spin-echo MR images of 13 patients with intraaortic thrombus documented by CT (N=11) or aortography (N=2). Six patients had aortic aneurysms and seven had aortic dissections. Intraaortic mural thrombi were accompanied by flow-related intraluminal signal of various pattern and extents in all 13 patients. On 10 gated MR studies, slow flow regions showed ever-echo rephasing phenomenon (N=8), interslice variation of signal intensities of the intraluminal signal (N=7) and flow-related ghost artifact (N=2). However, these MR flow phenomena were obscured on two of three non-gated studies. Seven of 13 intraaortic thrombi remained hyperintense on T2-weighted second-echo images. In these circumstance, a hypointense boundary layer between slow flow and mural thrombus, which was caused by either ' boundary layer dephasing phenomenon' of slow flow or 'paramagnetic T2 shortening' of fresh clot at the edge of mural thrombus, was very useful in discriminating the area of slow flow from that of mural thrombus. Proper interpretation of spin-echo MR images may obviate the need for phase display imaging or gradient-echo imaging in differentiating slow flow and mural thrombus
-
Directory of Open Access Journals (Sweden)
N. B. Vikhrova
2015-01-01
Full Text Available Renal cell carcinoma (RCC is the most common primary tumor of the renal parenchyma. Venous involvement is one of the most important anatomic characteristics of tumor. It is known that venous spread influences the survival of patients with RCC. Tumor thrombosis of IVC in patients with renal cell carcinoma has been reported in 4–10 %. The reference standard for RCC with tumor thrombus remains surgical resection. The structure of thrombus determines some technical difficulties in the management of tumor. Spongeous thrombus correlate with higher risk of thrombus detachment during surgery resulting in PE. Therefore determination of IVC thrombus consistency is very important part of preoperative radiologic assessment of tumor in patients with RCC.
-
Directory of Open Access Journals (Sweden)
Amitesh Aggarwal
2009-11-01
Full Text Available Endomyocardial fibrosis is a progressive disease of unknown origin affecting children and young adults. It involves inflow portion of right and/or left ventricle and apex. It may be associated with thrombus. Literature regarding right ventricular endomyocardial fibrosis with thrombus is scarce. Here we report a rare case of right ventricular endomyocardial fibrosis presenting as ventricular tachycardia and echocardiographic evidence of apical thrombus. Interestingly there was no pulmonary involvement or evidence of deep venous thrombosis. This case also underscores the importance of urgent echocardiography in diagnosis of obscure cases of ventricular tachycardia.
-
The binding of fibrinogen to platelets in diabetes mellitus
International Nuclear Information System (INIS)
Minno, G. di; Cerbone, A.M.; Iride, C.; Mancini, M.
1986-01-01
Platelets from diabetics are known to be more sensitive in vitro to a variety of aggregating agents, to produce more prostaglandin endoperoxides and thromboxane and to bind more 125 I-fibrinogen than platelets from normal controls. Fibrinogen binding to platelets is a pre-requisite for platelet aggregation. Previous studies suggested a role for prostaglandins and/or thrombaxane A 2 in the exposure of fibrinogen receptors on platelets. The present study compares fibrinogen binding to hyperaggregable platelets from diabetic patients and to normal platelets when prostaglandin/thromboxane formation is suppressed by aspirin. It was found that pre-treatment with aspirin reduced collagen or thrombin-induced binding to platelets from none-retinopathic diabetics to the values seen in controls. By contrast, aspirin did not normalize binding to platelets obtained from retinopathic diabetics. The combination of aspirin with apyrase (an ADP scavenger) almost completely inhibited binding and aggregation of platelets from normal controls or non-retinophatic diabetics exposed to collagen or thrombin, whereas it only partially affected binding and aggregation of platelets from retinopathics. By using a monoclonal antibody (B59.2) to the platelet receptor for fibrinogen, we determined that this receptor was quantitatively and qualitatively the same on platelets from normal controls and diabetics. We conclude that increased fibrinogen binding and hyperaggregability of platelets from none-retinopathic diabetics is related to their capacity to form more prostaglandin endoperoxides/thromboxane than normal platelets. In contrast, hyperaggregability and increased binding of platelets from retinopathics appear at least partly related to a mechanism independent of ADP release and thromboxane synthesis. (Author)
-
Advances and controversies in neonatal ICU platelet transfusion practice.
Christensen, Robert D
2008-01-01
Some of the platelet transfusions currently given to NICU patients are unnecessary and convey no benefits. Although ordered with good intentions, unnecessary platelet transfusions carry known and unknown risks. Identifying and eliminating any unnecessary platelet transfusions in NICUs would be a step toward better care, lower costs, and more careful preservation of blood component resources. A renewed interest in platelet transfusion studies is needed, if essential data is to be gathered to improve NICU platelet transfusion practice. Retrospective studies can be of value: for instance, seeking associations between bleeding events and platelet counts can suggest the possibility of cause and effect relationships. Such studies might identify approximate platelet count levels that convey high hemorrhagic risk and might help focus future prospective trials. Prospective indirect studies also can be of value, for instance, measuring the template bleeding time and the PFA-100 closure time as a function of platelet count and perhaps as a function of circulating platelet mass, and would provide new information with relevance to platelet transfusion benefits. Such studies might give a better awareness of how low the platelet count can fall before platelet plug formation is impaired. It seems inescapable, however, that new, multicentered, randomized, prospective studies are needed, where NICU patients are assigned different platelet transfusion triggers and then carefully tracked for bleeding events and long-term neurodevelopmental outcomes. Only that type of study is likely to generate the evidence base needed for widespread implementation of improvements in NICU platelet transfusion practice.
-
DEFF Research Database (Denmark)
Windeløv, Nis Agerlin; Johansson, Pär Ingemar; Sørensen, Anne Marie
2014-01-01
BACKGROUND: Following activation, platelets release small vesicles called platelet-derived microparticles (PMPs). PMPs accelerate thrombin generation and thus clot formation at sites of injury by exposing the procoagulant membrane phospholipid phosphatidylserine (PS). The role of PMPs in coagulop......BACKGROUND: Following activation, platelets release small vesicles called platelet-derived microparticles (PMPs). PMPs accelerate thrombin generation and thus clot formation at sites of injury by exposing the procoagulant membrane phospholipid phosphatidylserine (PS). The role of PMPs...
-
Measurement of platelet aggregation, independently of patient platelet count
DEFF Research Database (Denmark)
Vinholt, P J; Frederiksen, H; Hvas, A-M
2017-01-01
with collagen-related peptide). Platelet aggregation had a negative predictive value of 100% for a bleeding tendency among patients. Conclusion The established platelet aggregation assay was applicable for thrombocytopenic patients, and improved the identification of bleeding risk.......Essentials •Platelet function may influence bleeding risk in thrombocytopenia, but useful tests are needed. •A flow cytometric platelet aggregation test independent of the patient platelet count was made. •Platelet aggregation was reduced in thrombocytopenic patients with hematological cancer....... •High platelet aggregation ruled out bleeding tendency in thrombocytopenic patients. Summary Background Methods for testing platelet aggregation in thrombocytopenia are lacking. Objective To establish a flow-cytometric test of in vitro platelet aggregation independently of the patient's platelet count...
-
Platelets and infections—complex interactions with bacteria
Directory of Open Access Journals (Sweden)
Hind eHAMZEH-COGNASSE
2015-02-01
Full Text Available Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-Like Receptors but also integrins conventionally described in the hemostatic response, such as GPIIb-IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of Neutrophil Extracellular Traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet-bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the
-
Brisbois, Elizabeth J; Major, Terry C; Goudie, Marcus J; Bartlett, Robert H; Meyerhoff, Mark E; Handa, Hitesh
2016-06-01
Blood-contacting devices, including extracorporeal circulation (ECC) circuits, can suffer from complications due to platelet activation and thrombus formation. Development of nitric oxide (NO) releasing polymers is one method to improve hemocompatibility, taking advantage of the ability of low levels of NO to prevent platelet activation/adhesion. In this study a novel solvent swelling method is used to load the walls of silicone rubber tubing with the NO donor S-nitroso-N-acetylpenicillamine (SNAP). This SNAP-silicone rubber tubing exhibits an NO flux of ca. 1×10(-10)molcm(-2)min(-1), which mimics the range of NO release from the normal endothelium, which is stable for at least 4h. Images of the tubing before and after swelling, obtained via scanning electron microscopy, demonstrate that this swelling method has little effect on the surface properties of the tubing. The SNAP-loaded silicone rubber and silicone rubber control tubing are used to fabricate ECC circuits that are evaluated in a rabbit model of thrombogenicity. After 4h of blood flow, the SNAP-loaded silicone rubber circuits were able to preserve the blood platelet count at 64% of baseline (vs. 12% for silicone rubber control). A 67% reduction in the degree of thrombus formation within the thrombogenicity chamber was also observed. This study demonstrates the ability to improve the hemocompatibility of existing/commercial silicone rubber tubing via a simple solvent swelling-impregnation technique, which may also be applicable to other silicone-based blood-contacting devices. Localized nitric oxide (NO) release can be achieved from biomedical grade polymers doped with S-nitroso-N-acetylpenicillamine (SNAP). Despite the promising in vitro and in vivo biocompatibility results reported for these NO releasing polymers, many of these materials may face challenges in being translated to clinical applications, especially in the areas of polymer processing and manufacturing. In this study, we report a solvent
-
International Nuclear Information System (INIS)
Datz, F.L.; Taylor, A.T.
1986-01-01
Initial interest in developing techniques to radiolabel platelets was spurred by the lack of an accurate method for measuring platelet life span in both normals and in thrombocytopenic patients. Early investigators could obtain only rough estimates of platelet life spans by monitoring the platelet counts of thrombocytopenic patients undergoing platelet transfusions. Labels were also sought that would allow imaging of platelets in vivo in order to better understand the pathophysiology of atherosclerosis, thrombophlebitis, and clotting disorders, and to improve the clinical diagnosis of these diseases. Two types of platelet labels were investigated: cohort (pulse) labels and random labels. Cohort labels are taken up by megakaryocytes in the bone marrow and incorporated in the DNA and other components of the forming platelet. In theory, only freshly released platelets of a uniform age are labeled. Random labels, on the other hand, tag platelets in the peripheral blood, labeling platelets of all ages
-
Directory of Open Access Journals (Sweden)
İbrahim Eker
2017-03-01
Full Text Available Objective: In the last decade, substantial evidence has accumulated about the use of cryopreserved platelet concentrates, especially in trauma. However, little reference has been made in these studies to the morphological and functional changes of platelets. Recently platelets have been shown to be activated by cryopreservation processes and to undergo procoagulant membrane changes resulting in the generation of platelet-derived microparticles (PMPs, platelet degranulation, and release of platelet-derived growth factors (PDGFs. We assessed the viabilities and the PMP and PDGF levels of cryopreserved platelets, and their relation with thrombin generation. Materials and Methods: Apheresis platelet concentrates (APCs from 20 donors were stored for 1 day and cryopreserved with 6% dimethyl sulfoxide. Cryopreserved APCs were kept at -80 °C for 1 day. Thawed APCs (100 mL were diluted with 20 mL of autologous plasma and specimens were analyzed for viabilities and PMPs by flow cytometry, for thrombin generation by calibrated automated thrombogram, and for PDGFs by enzyme-linked immunosorbent assay testing. Results: The mean PMP and PDGF levels in freeze-thawed APCs were significantly higher (2763±399.4/μL vs. 319.9±80.5/μL, p<0.001 and 550.9±73.6 pg/mL vs. 96.5±49 pg/mL, p<0.001, respectively, but the viability rates were significantly lower (68.2±13.7% vs. 94±7.5%, p<0.001 than those of fresh APCs. The mean endogenous thrombin potential (ETP of freeze-thawed APCs was significantly higher than that of the fresh APCs (3406.1±430.4 nM.min vs. 2757.6±485.7 nM.min, p<0.001. Moreover, there was a significant positive poor correlation between ETP levels and PMP levels (r=0.192, p=0.014. Conclusion: Our results showed that, after cryopreservation, while levels of PMPs were increasing, significantly higher and earlier thrombin formation was occurring in the samples analyzed despite the significant decrease in viability. Considering the damage caused
-
Platelets and hemophilia: A review of the literature.
Riedl, Julia; Ay, Cihan; Pabinger, Ingrid
2017-07-01
Hemophilia A and B are inherited bleeding disorders due to deficiencies of the clotting factors VIII and IX, respectively. The severity of the disease correlates with remaining factor levels, although individual differences in bleeding tendency are seen despite similar factor levels. While thrombin generation is severely impaired in persons with hemophilia, primary hemostasis, i.e. platelet function, has been generally considered to be normal. However, some studies reported prolonged bleeding times in hemophilia, suggesting that also primary hemostasis is affected. In several other studies different aspects of platelet function in hemophilia have been investigated in more detail and various alterations were discovered, such as increased platelet P-selectin expression, a lower number of procoagulant, so-called 'coated' platelets, lower aggregation upon co-incubation with tissue factor, or reduced platelet contractile forces during clot formation in comparison to healthy individuals. An influence of platelet function on clinical phenotype was suggested, which might contribute in part to variations in bleeding tendency in hemophilic patients with similar factor levels. However, the available evidence is currently limited and no clear correlations between platelet function parameters and clinical phenotypes have been demonstrated. The impact of alterations of platelet function in hemophilia remains to be better defined. Another interesting role of platelets in hemophilia has been reported recently by establishing a novel gene-therapeutic strategy using platelets as a delivery system for FVIII, showing promising results in animal models. This review gives an overview on the currently published literature on platelet function and the potential roles of platelets in hemophilia. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
A Therapeutic Challenge: Management of Atrial Thrombus
Directory of Open Access Journals (Sweden)
Serkan Burc Deser
2016-09-01
Full Text Available Introduction: Primary cause of atrial thrombi include atrial fibrillation, foreign bodies inside the atrium such as catheters and pacemaker leads, emboli of deep venous thrombus and primary or metastatic tumors of the heart. We review the clinical features, epidemiology, diagnosis and treatment of nine intriguing cases with atrial thrombus. Methods: This is a retrospective study of nine patients (seven female (78%, two male (33% who were diagnosed with atrial thrombi (average age of 50 ± 12 years and were treated at the Ondokuz Mayis University, Department of Cardiovascular Surgery from February 2014 to January 2015. Among them, six patients had atrial fibrillation (one male, five female, seven patients were suffering from dispne and orthopnoea, five patients were suffering from leg swelling, seven patients had a history of hypertension and three patients had a history of mitral valve replacement surgery. Results: All patients underwent surgery except one. Four patients recovered uneventfully and discharged with oral anticoagulation (warfarin therapy (adjusted to maintain an international normalized ratio of INR between two and three times. Five of nine patients (55% died after surgery. Conclusion: The response to the thrombolytic therapy is poor, mostly ineffective and unsafe so it is often recommended as a bridge to surgery. In patients diagnosed with mechanical mitral valve thrombosis, medical therapy has the possibility of end organ emboli and also fail to resolve the organised thrombus on the stuck valve. On the other hand surgery does not always give satisfactory results. J Clin Exp Invest 2016; 7(4: 278-282
-
Juhan, I; Bayle, J; Mattei, J F; Thevenieau, D; Perrimond, H; Muratore, R
1979-10-01
The authors report on two cases of congenital thrombopenia with radial aplasia. Both children display several formative abnormalities and a mild thrombopenia; hemorragic manifestations occurred in the first case only. Megacryoblastic to platelets series, as studied with electronic microscopy, show small-sized, "microcytic" and hypogranular megacaryocytes, displaying a maturative disorder (dysmegacaryocytopoiesis). In functional studies, platelets of the first patient show an imperfect nucleotidic release and do not agregate normally with ristocetin. The second case exhibits mostly a PF3 reduction. The variety of expression of the megacaryocytic-platelets disorders appears likewise in the squelettal and visceral malformations. The whole disorder could be ascribed to a pleiotropic abnormal gene with a variable expressivity.
-
Platelet size does not correlate with platelet age.
Thompson, C B; Love, D G; Quinn, P G; Valeri, C R
1983-08-01
The relationship between platelet size and in vivo aging was investigated in the baboon using size-dependent platelet subpopulations separated by counterflow centrifugation. The separation characteristics, size, lactate dehydrogenase (LDH) activity, and dense-body content of the baboon platelet subpopulations were similar to those previously observed in studies of human platelets. Three independent labeling techniques were used: (1) in vivo labeling with 75Se-methionine, (2) in vitro labeling with 51Cr, and (3) in vivo labeling with 14C-serotonin. Maximal incorporation of all three labels showed a close correlation between the mean platelet volume (MPV) of each fraction and the platelet radioactivity. The onset of incorporation and rate of accumulation of 75Se-methionine were comparable in all fractions when corrected for differences in volume, suggesting that platelet size heterogeneity was present from the time of release of the platelets from the bone marrow. Survival studies using 51Cr and 14C-serotonin showed no translocation of the label from one fraction to another in the circulation over time. In vivo survival values for the three radionuclides showed a slight but significant correlation between the lifespan and the MPV of the fractions. The data suggest that large platelets were not younger platelets, but rather platelets with a longer life-span. Platelet size heterogeneity is the result of production factors in the bone marrow and not maturation in the circulation.
-
Platelet size does not correlate with platelet age
International Nuclear Information System (INIS)
Thompson, C.B.; Love, D.G.; Quinn, P.G.; Valeri, C.R.
1983-01-01
The relationship between platelet size and in vivo aging was investigated in the baboon using size-dependent platelet subpopulations separated by counterflow centrifugation. The separation characteristics, size, lactate dehydrogenase (LDH) activity, and dense-body content of the baboon platelet subpopulations were similar to those previously observed in studies of human platelets. Three independent labeling techniques were used: (1) in vivo labeling with 75 Se-methionine, (2) in vitro labeling with 51 Cr, and (3) in vivo labeling with 14C-serotonin. Maximal incorporation of all three labels showed a close correlation between the mean platelet volume (MPV) of each fraction and the platelet radioactivity. The onset of incorporation and rate of accumulation of 75 Se-methionine were comparable in all fractions when corrected for differences in volume, suggesting that platelet size heterogeneity was present from the time of release of the platelets from the bone marrow. Survival studies using 51 Cr and 14 C-serotonin showed no translocation of the label from one fraction to another in the circulation over time. In vivo survival values for the three radionuclides showed a slight but significant correlation between the lifespan and the MPV of the fractions. The data suggest that large platelets were not younger platelets, but rather platelets with a longer life-span. Platelet size heterogeneity is the result of production factors in the bone marrow and not maturation in the circulation
-
The method of thrombolytic radioassay in vitro
International Nuclear Information System (INIS)
Yang Yi; Zhao Zhuanyou; Liu Houxiao; Niu Huisheng; Li Huaifen; Wang Yinlan
1998-01-01
The similar nature thrombus is made of 125 I-fibrinogen with platelet-rich or antithrombotic blood to culture together with platelet-rich plasma and thrombolytic agent. The thrombolytic rate is calculated depending on the radioactivity of plasma. At the same time, some relative factors with thrombus and thrombolytic effects of recombinant staphylokinase (STAR) is discussed. These results show that radioassay technology is sensitive, stable, specific and wonderful method
-
CT diagnosis of tumor thrombus of the renal vein and inferior vena cava
International Nuclear Information System (INIS)
Masuda, Fujio; Chen, Zuicho; Oishi, Yukihiko; Machida, Toyohei
1980-01-01
We used computed tomography (CT) for diagnosis in 4 cases of renal tumor associated with tumor thrombus of the renal vein and inferior vana cava. The results obtained are described below: A total of 4 cases consisting of 3 cases of renal cell carcinoma and one case of squamous cell carcinoma of the renal pelvis, treated at the Jikei University Hospital during the six months period from January to June of 1979, were studied. The affected side was right in 3 cases and left in one case. In all of the former cases the tumor thrombus was extending from the renal vein to the inferior vena cava, while in the latter case it was confined in the renal vein. All these 4 cases received CT together with renal arteriography and inferior venacavography, followed by nephrectomy, and were confirmed of the presence of tumor thrombus in the renal vein and inferior vena cava operatively. CT findings revealed a pronounced enlargement of the renal vein, and tumor thrombus of the renal vein was diagnosed in all of the 4 cases. In 2 of 3 cases in which tumor thrombus extended to the inferior vena cava, the dilated renal vein was found to be connected to the slightly dilated inferior vena cava, while in the remaining one case the outline of the inferior vena cava was obscure, showing no clear dilatation. After contrast enhancement, a filling defect was seen in the inferior vena cava. CT findings of tumor thrombus in the vein indicated a dilatation of the renal vein and inferior vena cava. In addition, a filling defect was found after contrast enhancement, suggesting that CT is helpful as a diagnostic aid. (author)
-
Directory of Open Access Journals (Sweden)
Monique Ramos de Oliveira Trugilho
2017-05-01
Full Text Available Dengue is the most prevalent human arbovirus disease worldwide. Dengue virus (DENV infection causes syndromes varying from self-limiting febrile illness to severe dengue. Although dengue pathophysiology is not completely understood, it is widely accepted that increased inflammation plays important roles in dengue pathogenesis. Platelets are blood cells classically known as effectors of hemostasis which have been increasingly recognized to have major immune and inflammatory activities. Nevertheless, the phenotype and effector functions of platelets in dengue pathogenesis are not completely understood. Here we used quantitative proteomics to investigate the protein content of platelets in clinical samples from patients with dengue compared to platelets from healthy donors. Our assays revealed a set of 252 differentially abundant proteins. In silico analyses associated these proteins with key molecular events including platelet activation and inflammatory responses, and with events not previously attributed to platelets during dengue infection including antigen processing and presentation, proteasome activity, and expression of histones. From these results, we conducted functional assays using samples from a larger cohort of patients and demonstrated evidence for platelet activation indicated by P-selectin (CD62P translocation and secretion of granule-stored chemokines by platelets. In addition, we found evidence that DENV infection triggers HLA class I synthesis and surface expression by a mechanism depending on functional proteasome activity. Furthermore, we demonstrate that cell-free histone H2A released during dengue infection binds to platelets, increasing platelet activation. These findings are consistent with functional importance of HLA class I, proteasome subunits, and histones that we found exclusively in proteome analysis of platelets in samples from dengue patients. Our study provides the first in-depth characterization of the platelet
-
The life cycle of platelet granules [version 1; referees: 2 approved
Directory of Open Access Journals (Sweden)
Anish Sharda
2018-02-01
Full Text Available Platelet granules are unique among secretory vesicles in both their content and their life cycle. Platelets contain three major granule types—dense granules, α-granules, and lysosomes—although other granule types have been reported. Dense granules and α-granules are the most well-studied and the most physiologically important. Platelet granules are formed in large, multilobulated cells, termed megakaryocytes, prior to transport into platelets. The biogenesis of dense granules and α-granules involves common but also distinct pathways. Both are formed from the trans-Golgi network and early endosomes and mature in multivesicular bodies, but the formation of dense granules requires trafficking machinery different from that of α-granules. Following formation in the megakaryocyte body, both granule types are transported through and mature in long proplatelet extensions prior to the release of nascent platelets into the bloodstream. Granules remain stored in circulating platelets until platelet activation triggers the exocytosis of their contents. Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE proteins, located on both the granules and target membranes, provide the mechanical energy that enables membrane fusion during both granulogenesis and exocytosis. The function of these core fusion engines is controlled by SNARE regulators, which direct the site, timing, and extent to which these SNAREs interact and consequently the resulting membrane fusion. In this review, we assess new developments in the study of platelet granules, from their generation to their exocytosis.
-
Directory of Open Access Journals (Sweden)
D. D. Zhernossekov
2017-04-01
Full Text Available Plasminogen/plasmin system is known for its ability to support hemostatic balance of blood. However, plasminogen may be considered as an adhesive ligand and in this way could affect the functioning of blood cells. We showed that exogenous Lys-plasminogen, but not its Glu-form, inhibited platelet aggregation and suppressed platelet α-granule secretion. The aim of this work was to investigate the influence of Glu- and Lys-form of plasminogen on the formation of platelet procoagulant surface using phosphatidylserine exposure as a marker. Human platelets were obtained from human platelet-rich plasma (donors were healthy volunteers, men aged 30-40 years by gel-filtration on Sepharose 2B. Phosphatidylserine exposure on the platelet surface was evaluated by flow cytometry with FITC-conjugated annexin A5. Glu- and Lys-plasminogen have different impact on the platelet functioning. Exogenous Lys-plasminogen has no significant effect on phosphatidylserine exposure, while Glu-plasminogen increases phosphatidylserine exposure on the surface of thrombin- and collagen-activated human platelets. Glu-plasminogen can be considered as a co-stimulator of agonist-induced platelet secretion and procoagulant surface formation. Meanwhile effects of Lys-plasminogen are probably directed at platelet-platelet interactions and not related to agonist-stimulated pro-apoptotic changes. The observed different effects of Glu- and Lys-plasminogen on phosphatidylserine exposure can be explained by their structural peculiarities.
-
Niacin and biosynthesis of PGD2 by platelet COX-1 in mice and humans
Song, Wen-Liang; Stubbe, Jane; Ricciotti, Emanuela; Alamuddin, Naji; Ibrahim, Salam; Crichton, Irene; Prempeh, Maxwell; Lawson, John A.; Wilensky, Robert L.; Rasmussen, Lars Melholt; Puré, Ellen; FitzGerald, Garret A.
2012-01-01
The clinical use of niacin to treat dyslipidemic conditions is limited by noxious side effects, most commonly facial flushing. In mice, niacin-induced flushing results from COX-1–dependent formation of PGD2 and PGE2 followed by COX-2–dependent production of PGE2. Consistent with this, niacin-induced flushing in humans is attenuated when niacin is combined with an antagonist of the PGD2 receptor DP1. NSAID-mediated suppression of COX-2–derived PGI2 has negative cardiovascular consequences, yet little is known about the cardiovascular biology of PGD2. Here, we show that PGD2 biosynthesis is augmented during platelet activation in humans and, although vascular expression of DP1 is conserved between humans and mice, platelet DP1 is not present in mice. Despite this, DP1 deletion in mice augmented aneurysm formation and the hypertensive response to Ang II and accelerated atherogenesis and thrombogenesis. Furthermore, COX inhibitors in humans, as well as platelet depletion, COX-1 knockdown, and COX-2 deletion in mice, revealed that niacin evoked platelet COX-1–derived PGD2 biosynthesis. Finally, ADP-induced spreading on fibrinogen was augmented by niacin in washed human platelets, coincident with increased thromboxane (Tx) formation. However, in platelet-rich plasma, where formation of both Tx and PGD2 was increased, spreading was not as pronounced and was inhibited by DP1 activation. Thus, PGD2, like PGI2, may function as a homeostatic response to thrombogenic and hypertensive stimuli and may have particular relevance as a constraint on platelets during niacin therapy. PMID:22406532
-
Blood platelet kinetics and platelet transfusion
Aster, Richard H.
2013-01-01
The discovery of citrate anticoagulant in the 1920s and the development of plastic packs for blood collection in the 1960s laid the groundwork for platelet transfusion therapy on a scale not previously possible. A major limitation, however, was the finding that platelet concentrates prepared from blood anticoagulated with citrate were unsuitable for transfusion because of platelet clumping. We found that this could be prevented by simply reducing the pH of platelet-rich plasma to about 6.5 pr...
-
Evaluation of the TEG® platelet mappingTM assay in blood donors
DEFF Research Database (Denmark)
Bochsen, Louise; Wiinberg, Bo; Kjelgaard-Hansen, Mads Jens
2007-01-01
for quantification of platelet function, including the contribution of the adenosine diphosphate (ADP) and thromboxane A2 (TxA2) receptors to clot formation. Methods In 43 healthy blood donors, the analytical (CVa) and inter-individual variability (CVg) of the TEG® Platelet MappingTM assay were determined together......Background Monitoring of antiplatelet therapy in patients at cardiovascular risk is difficult because existing platelet function tests are too sophisticated for clinical routine. The whole blood TEG® Platelet MappingTM assay measures clot strength as maximal amplitude (MA) and enables...
-
Comparison of platelet formation in hydrogen and helium-implanted silicon
International Nuclear Information System (INIS)
Hebras, X.; Nguyen, P.; Bourdelle, K.K.; Letertre, F.; Cherkashin, N.; Claverie, A.
2007-01-01
A comparative transmission electron microscopy study of the extended defects formed in (0 0 1) Si after hydrogen or helium implantation was performed. Quantitative data on the size and density of the defects with different crystallographic variants have been obtained. Common defects observed after implants with a dose of 1 x 10 16 cm -2 and isothermal anneals at 350 o C in the presence of a stiffener were platelet-like structures lying on {1 0 0} habit planes parallel and perpendicular to the wafer surface. The differences in the defect morphology and in the variant platelet population are correspondingly related to the different chemical reactivity of H and He and the different compressive biaxial stresses generated by the H and He implants
-
Dysfunctional nitric oxide signalling increases risk of myocardial infarction.
Erdmann, Jeanette; Stark, Klaus; Esslinger, Ulrike B; Rumpf, Philipp Moritz; Koesling, Doris; de Wit, Cor; Kaiser, Frank J; Braunholz, Diana; Medack, Anja; Fischer, Marcus; Zimmermann, Martina E; Tennstedt, Stephanie; Graf, Elisabeth; Eck, Sebastian; Aherrahrou, Zouhair; Nahrstaedt, Janja; Willenborg, Christina; Bruse, Petra; Brænne, Ingrid; Nöthen, Markus M; Hofmann, Per; Braund, Peter S; Mergia, Evanthia; Reinhard, Wibke; Burgdorf, Christof; Schreiber, Stefan; Balmforth, Anthony J; Hall, Alistair S; Bertram, Lars; Steinhagen-Thiessen, Elisabeth; Li, Shu-Chen; März, Winfried; Reilly, Muredach; Kathiresan, Sekar; McPherson, Ruth; Walter, Ulrich; Ott, Jurg; Samani, Nilesh J; Strom, Tim M; Meitinger, Thomas; Hengstenberg, Christian; Schunkert, Heribert
2013-12-19
Myocardial infarction, a leading cause of death in the Western world, usually occurs when the fibrous cap overlying an atherosclerotic plaque in a coronary artery ruptures. The resulting exposure of blood to the atherosclerotic material then triggers thrombus formation, which occludes the artery. The importance of genetic predisposition to coronary artery disease and myocardial infarction is best documented by the predictive value of a positive family history. Next-generation sequencing in families with several affected individuals has revolutionized mutation identification. Here we report the segregation of two private, heterozygous mutations in two functionally related genes, GUCY1A3 (p.Leu163Phefs*24) and CCT7 (p.Ser525Leu), in an extended myocardial infarction family. GUCY1A3 encodes the α1 subunit of soluble guanylyl cyclase (α1-sGC), and CCT7 encodes CCTη, a member of the tailless complex polypeptide 1 ring complex, which, among other functions, stabilizes soluble guanylyl cyclase. After stimulation with nitric oxide, soluble guanylyl cyclase generates cGMP, which induces vasodilation and inhibits platelet activation. We demonstrate in vitro that mutations in both GUCY1A3 and CCT7 severely reduce α1-sGC as well as β1-sGC protein content, and impair soluble guanylyl cyclase activity. Moreover, platelets from digenic mutation carriers contained less soluble guanylyl cyclase protein and consequently displayed reduced nitric-oxide-induced cGMP formation. Mice deficient in α1-sGC protein displayed accelerated thrombus formation in the microcirculation after local trauma. Starting with a severely affected family, we have identified a link between impaired soluble-guanylyl-cyclase-dependent nitric oxide signalling and myocardial infarction risk, possibly through accelerated thrombus formation. Reversing this defect may provide a new therapeutic target for reducing the risk of myocardial infarction.
-
Directory of Open Access Journals (Sweden)
Trevor P. Fidler
2017-07-01
Full Text Available Anucleate platelets circulate in the blood to facilitate thrombosis and diverse immune functions. Platelet activation leading to clot formation correlates with increased glycogenolysis, glucose uptake, glucose oxidation, and lactic acid production. Simultaneous deletion of glucose transporter (GLUT 1 and GLUT3 (double knockout [DKO] specifically in platelets completely abolished glucose uptake. In DKO platelets, mitochondrial oxidative metabolism of non-glycolytic substrates, such as glutamate, increased. Thrombosis and platelet activation were decreased through impairment at multiple activation nodes, including Ca2+ signaling, degranulation, and integrin activation. DKO mice developed thrombocytopenia, secondary to impaired pro-platelet formation from megakaryocytes, and increased platelet clearance resulting from cytosolic calcium overload and calpain activation. Systemic treatment with oligomycin, inhibiting mitochondrial metabolism, induced rapid clearance of platelets, with circulating counts dropping to zero in DKO mice, but not wild-type mice, demonstrating an essential role for energy metabolism in platelet viability. Thus, substrate metabolism is essential for platelet production, activation, and survival.
-
Procoagulant expression in platelets and defects leading to clinical disorders.
Solum, N O
1999-12-01
Hemostasis is a result of interactions between fibrillar structures in the damaged vessel wall, soluble components in plasma, and cellular elements in blood represented mainly by platelets and platelet-derived material. During formation of a platelet plug at the damaged vessel wall, factors IXa and VIIIa form the "tenase" complex, leading to activation of factor X on the surface of activated platelets. Subsequently, factors Xa and Va form the "prothrombinase" complex, which catalyzes the formation of thrombin from prothrombin, leading to fibrin formation. An enhanced expression of negatively charged phosphatidylserine in the outer membrane leaflet resulting from a breakdown of the phospholipid asymmetry is essential for the formation of the procoagulant surface. An ATP-driven and inward-acting aminophospholipid "translocase" and a "floppase" counterbalancing this have been postulated to maintain the dynamic state of phospholipid asymmetry. A phospholipid-nonspecific "scramblase," believed to be responsible for the fast breakdown of the asymmetry during cell activation, has recently been isolated from erythrocytes, cloned, and characterized. An intracellular calcium-binding segment and one or more thioesterified fatty acids are probably of importance for calcium-induced activation of this transporter protein. Cytosolic calcium ions also activate the calcium-dependent protease calpain associated with shedding of microvesicles from the transformed platelet membrane. These are shed with a procoagulant surface and with surface-exposed P-selectin from the alpha-granules. Theoretically, therefore, microvesicles can be involved in both coagulation and inflammation. Scott syndrome is probably caused by a defect in the activation of an otherwise normal scramblase, resulting in a relatively severe bleeding tendency. In Stormorken syndrome, the patients demonstrate a spontaneous surface expression of aminophospholipids. Activated platelets and the presence of procoagulant
-
[Stroke due to infective endocarditis diagnosed by the retrieved thrombus: a case report].
Nakanishi, Kaoru; Kawano, Hiroyuki; Amano, Tatsuo; Omori, Yoshihiko; Kanma, Hiroshi; Hirano, Teruyuki
2018-01-26
A 80-years-old woman suddenly presented with aphasia, right hemiparesis, and dysesthesia. MRA showed the left middle cerebral artery occlusion. She was diagnosed as hyperacute ischemic stroke. She was treated with intravenous recombinant tissue plasminogen activator and underwent endovascular thrombectomy. On admission, she had a fever and high C reactive protein, and was treated with antibiotic therapy. The pathological diagnosis of the retrieved thrombus revealed the cluster of the gram positive cocci. The blood culture was negative and thransthoracic echocardiogram did not detect the vegetation. She was finally diagnosed as cardioembolic stroke due to infective endocarditis based on the pathological diagnosis of the retrieved thrombus. The pathological diagnosis of the retrieved thrombus was quite important to clarify the cause of ischemic stroke.
-
Platelet-derived growth factor inhibits platelet activation in heparinized whole blood.
Selheim, F; Holmsen, H; Vassbotn, F S
1999-08-15
We previously have demonstrated that human platelets have functionally active platelet-derived growth factor alpha-receptors. Studies with gel-filtered platelets showed that an autocrine inhibition pathway is transduced through this tyrosine kinase receptor during platelet activation. The physiological significance of this inhibitory effect of platelet-derived growth factor on gel-filtered platelets activation is, however, not known. In the present study, we investigated whether platelet-derived growth factor inhibits platelet activation under more physiological conditions in heparinized whole blood, which represents a more physiological condition than gel-filtered platelets. Using flow cytometric assays, we demonstrate here that platelet-derived growth factor inhibits thrombin-, thrombin receptor agonist peptide SFLLRN-, and collagen-induced platelet aggregation and shedding of platelet-derived microparticles from the platelet plasma membrane during platelet aggregation in stirred heparinized whole blood. The inhibitory effect of platelet-derived growth factor was dose dependent. However, under nonaggregating conditions (no stirring), we could not demonstrate any significant effect of platelet-derived growth factor on thrombin- and thrombin receptor agonist peptide-induced platelet surface expression of P-selectin. Our results demonstrate that platelet-derived growth factor appears to be a true antithrombotic agent only under aggregating conditions in heparinized whole blood.
-
Energy Technology Data Exchange (ETDEWEB)
Cheng, Tan; Rongjun, Zhang; Weixing, Wan; Gangming, Cai; Huixin, Yu; Mengjun, Jiang; Lianfen, Zhang; Guoping, Sheng; Yijun, Fan; Yonghui, Tao; Jian, Jin [Jiangsu Inst. of Nuclear Medicine, Wuxi (China)
2003-07-01
The purpose of this study is to evaluate the effect of recombinant hirudin HV2 (rHHV2) as a thrombus imaging agent. {sup 125}I-rHHV2 and {sup 125}I-Th were prepared with Chloramine method, the labeling rate were 86.64% and 62.20%, with the radioactive purity of 89.70% and 91.22%, with the specific activity of 22.4 TBq/mmol and 94.43 TBq/mmol respectively. The competitive radioassay showed that the Th-fibrin complex formation did not affect the ability of rHHV2 binding with Th. In the complex, the molecular binding ratio of rHHV2 to Th and fibrinogen was 14:14:1. {sup 99m}Tc-rHHV2 was prepared by 2-iminothiolane modified method, the labeled rate was 94%, with the radioactive purity of 93.90%, with the specific activity of 2.30 TBq/mmol. It was used to image fresh thrombi on arteries and veins of dog or rabbit (30 {mu}g/kg). In SPECT images, all thrombin were clearly visible, arterial thrombosis imaging can be seen clearly within 45 min after injection and fade away slowly, venous thrombosis imaging also can be seen within 30 min after injection and quantitative imaging ratios between the thrombus and opposite vessel increased following the time. Biodistribution studies in mouse demonstrated that rHHV2 was excreted from kidneys. These data indicate that Th in Th-fibrin complex could be a potent target for diagnosis of thrombus and {sup 99m}Tc-rHHV2 could be a new thrombotic imaging agent. (authors)
-
Systematic Review of Treatment for Trapped Thrombus in Patent Foramen Ovale.
Seo, Won-Woo; Kim, Sung Eun; Park, Myung-Soo; Lee, Jun-Hee; Park, Dae-Gyun; Han, Kyoo-Rok; Oh, Dong-Jin
2017-09-01
Trapped thrombus in patent foramen ovale (PFO) is a rare complication of pulmonary embolism that may lead to tragic clinical events. The aim of this study was to identify the optimal treatment for different clinical situations in patients with trapped thrombus in a PFO by conducting a literature review. A PubMed database search was conducted from 1991 through 2015, and 194 patients (185 articles) with trapped thrombus in a PFO were identified. Patient characteristics, paradoxical embolic events, and factors affecting 60-day mortality were analyzed retrospectively. Among all patients, 112 (57.7%) were treated with surgery, 28 with thrombolysis, and 54 with anticoagulation alone. Dyspnea (79.4%), chest pain (33.0%), and syncope (17.5%) were the most common presenting symptoms. Pretreatment embolism was found in 37.6% of cases, and stroke (24.7%) was the most common event. Surgery was associated with fewer post-treatment embolic events than were other treatment options (p=0.044). In the multivariate analysis, initial shock or arrest, and thrombolysis were independent predictors of 60-day mortality. Thrombolysis was related with higher 60-day mortality compared with surgery in patients who had no initial shock or arrest. This systematic review showed that surgery was associated with a lower overall incidence of post-treatment embolic events and a lower 60-day mortality in patients with trapped thrombus in a PFO. In patients without initial shock or arrest, thrombolysis was related with a higher 60-day mortality compared with surgery.
-
LENUS (Irish Health Repository)
McCabe, D J H
2005-09-01
The risk of stroke in patients with recently symptomatic carotid stenosis is considerably higher than in patients with asymptomatic stenosis. In the present study it was hypothesised that excessive platelet activation might partly contribute to this difference.
-
A critical role of platelet TGF-β release in podoplanin-mediated tumour invasion and metastasis.
Takemoto, Ai; Okitaka, Mina; Takagi, Satoshi; Takami, Miho; Sato, Shigeo; Nishio, Makoto; Okumura, Sakae; Fujita, Naoya
2017-02-08
The tumour microenvironment is critical for various characteristics of tumour malignancies. Platelets, as part of the tumour microenvironment, are associated with metastasis formation via increasing the rate of tumour embolus formation in microvasculature. However, the mechanisms underlying the ability of tumour cells to acquire invasiveness and extravasate into target organs at the site of embolization remain unclear. In this study, we reported that platelet aggregation-inducing factor podoplanin expressed on tumour cell surfaces were found to not only promote the formation of tumour-platelet aggregates via interaction with platelets, but also induced the epithelial-mesenchymal transition (EMT) of tumour cells by enhancing transforming growth factor-β (TGF-β) release from platelets. In vitro and in vivo analyses revealed that podoplanin-mediated EMT resulted in increased invasiveness and extravasation of tumour cells. Treatment of mice with a TGF-β-neutralizing antibody statistically suppressed podoplanin-mediated distant metastasis in vivo, suggesting that podoplanin promoted haematogenous metastasis in part by releasing TGF-β from platelets that was essential for EMT of tumour cells. Therefore, our findings suggested that blocking the TGF-β signalling pathway might be a promising strategy for suppressing podoplanin-mediated haematogenous metastasis in vivo.
-
Directory of Open Access Journals (Sweden)
Renáta Hudák
2017-01-01
Full Text Available The aim of this study was to investigate the effect of the serine/threonine protein phosphatase inhibitor, calyculin-A (CLA, on clot formation and on the procoagulant activity of human platelets. Platelet-rich plasma (PRP samples were preincubated with buffer or CLA and subsequently platelets were activated by the protease-activated receptor 1 (PAR-1 activator, thrombin receptor activating peptide (TRAP. Clot retraction was detected by observing clot morphology up to 1 hour, phosphatidylserine- (PS- expression was studied by flow cytometry, and thrombin generation was measured by a fluorimetric assay. For the intracellular Ca2+ assay, platelets were loaded with calcium-indicator dyes and the measurements were carried out using a ratiometric method with real-time confocal microscopy. CLA preincubation inhibited clot retraction, PS-expression, and thrombin formation. TRAP activation elicited Ca2+ response and PS-expression in a subset of platelets. The activated PRP displayed significantly faster and enhanced thrombin generation compared to nonactivated samples. CLA pretreatment abrogated PS-exposure and clot retraction also in TRAP-activated samples. As a consequence of the inhibitory effect on calcium elevation and PS-expression, CLA significantly downregulated thrombin generation in PRP. Our results show that CLA pretreatment may be a useful tool to investigate platelet activation mechanisms that contribute to clot formation and thrombin generation.
-
GIANT PROSTHETIC VALVE THROMBUS
Directory of Open Access Journals (Sweden)
Prashanth Kumar
2015-04-01
Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.
-
Defining Platelet Function During Polytrauma
2014-04-01
scaffold of the clot after its thrombin-induced polymerization to fibrin fibers. Formation of a stiff fibrin fiber network and its contraction by platelet...In another study (PROTEC T) Refused Participat ion (Yes=Y, No=N, W=Unqua lified , Refused further draws (agreed to keep previous data
-
Effect of Cold Storage on Shear-induced Platelet Aggregation and Clot Strength
2014-09-01
hemostasis and are lifesavingwhen transfused to treat thrombocytopenia. In response to vascular injury, platelets adhere, aggregate, and along with fibrin ...Handling Platelet - rich plasma (PRP) was obtained from phlebot- omized blood or AP collection. Blood was drawn in acid cit- rate dextroseYcontaining...aging and senes- cence during storage.35,38 Platelet activation and aggregation lead to clot formation, beginning with the linear polymerization of fibrin
-
Mehta, Ninfa; Schecter, Joshua; Stone, Michael
2012-05-01
Traditionally, the diagnosis of deep venous thrombosis (DVT) using duplex ultrasonography (DU) has relied on the absence of venous compressibility. Visualization of an intraluminal thrombus is considered an uncommon finding. The purpose of this study is to determine the frequency of intraluminal thrombus in emergency department (ED) patients diagnosed with acute DVT. Retrospective chart review of adult ED patients with DU examinations demonstrating acute DVT. Patients with chronic DVT or patients in whom DU did not demonstrate DVT were excluded from data analysis. Study reports and ultrasound images were reviewed and analyzed for the presence of intraluminal thrombus. There were 189 patients who met inclusion criteria, of which 160 (85%) were found to have intraluminal thrombus. Intraluminal thrombi are present in the majority of patients in our ED in whom acute DVT is identified by DU. Copyright © 2012 Elsevier Inc. All rights reserved.
-
Pavabvash, Seyedmehdi; Taleb, Shayandokht; Majidi, Shahram; Qureshi, Adnan I
2017-01-01
The location of the arterial occlusion can help with prognostication and treatment triage of acute stroke patients. We aimed to determine the effects of M1 distance-to-thrombus on angiographic recanalization success rate and clinical outcome following endovascular treatment of acute M1 occlusion. All acute ischemic stroke patients with M1 segment middle cerebral artery (MCA) occlusion on admission CT angiography (CTA) who underwent endovascular treatment were analyzed. The distance between thrombus origin and internal carotid artery (ICA) bifurcation was measured on admission CTA. The modified thrombolysis in cerebral infarction (mTICI) grades 2 b (>50% of distal branch filling) and 3 (complete) were considered as successful recanalization. Favorable outcome was defined by 3-month follow-up modified Rankin scale (mRs) score ≤2. Successful recanalization was achieved in 24 (71%) of 34 consecutive patients included in this study. The M1 distance-to-thrombus was shorter among patients with successful recanalization (5.4 ± 5.4 mm) versus those without (11.3 ± 7.6 mm, p = 0.015). The successful recanalization rate was higher among patients with M1 distance-to-thrombus ≤6 mm (odds ratio: 8, 95% confidence interval: 1.37-46.81, p = 0.023) compared with those with distance-to-thrombus >6 mm. There was no significant correlation between M1 distance-to-thrombus and 3-month mRs (rho: 0.131, p = 0.461); however, the distance-to-thrombus negatively correlated with admission National Institutes of Health Stroke Scale (NIHSS) scores (rho: -0.350, p=0.043). On the other hand, successful recanalization and admission NIHSS score were the only independent predictors of favorable outcome. Shorter distance of M1 thrombus from ICA bifurcation is associated with higher rate of successful recanalization following endovascular treatment.
-
Pavabvash, Seyedmehdi; Taleb, Shayandokht; Majidi, Shahram; Qureshi, Adnan I.
2017-01-01
Purpose The location of the arterial occlusion can help with prognostication and treatment triage of acute stroke patients. We aimed to determine the effects of M1 distance-to-thrombus on angiographic recanalization success rate and clinical outcome following endovascular treatment of acute M1 occlusion. Methods All acute ischemic stroke patients with M1 segment middle cerebral artery (MCA) occlusion on admission CT angiography (CTA) who underwent endovascular treatment were analyzed. The distance between thrombus origin and internal carotid artery (ICA) bifurcation was measured on admission CTA. The modified thrombolysis in cerebral infarction (mTICI) grades 2b (>50% of distal branch filling) and 3 (complete) were considered as successful recanalization. Favorable outcome was defined by 3-month follow-up modified Rankin scale (mRs) score ≤2. Results Successful recanalization was achieved in 24 (71%) of 34 consecutive patients included in this study. The M1 distance-to-thrombus was shorter among patients with successful recanalization (5.4 ± 5.4 mm) versus those without (11.3 ± 7.6 mm, p = 0.015). The successful recanalization rate was higher among patients with M1 distance-to-thrombus ≤6 mm (odds ratio: 8, 95% confidence interval: 1.37–46.81, p = 0.023) compared with those with distance-to-thrombus >6 mm. There was no significant correlation between M1 distance-to-thrombus and 3-month mRs (rho: 0.131, p = 0.461); however, the distance-to-thrombus negatively correlated with admission National Institutes of Health Stroke Scale (NIHSS) scores (rho: −0.350, p=0.043). On the other hand, successful recanalization and admission NIHSS score were the only independent predictors of favorable outcome. Conclusion Shorter distance of M1 thrombus from ICA bifurcation is associated with higher rate of successful recanalization following endovascular treatment. PMID:28243346
-
Directory of Open Access Journals (Sweden)
Kosuke Endo
2016-04-01
Full Text Available Hepatoblastoma with intraatrial tumor thrombus is relatively rare. We report a case of hepatoblastoma with tumor thrombus extending into the right atrium, which responded well to chemotherapy and was resected using extracorporeal circulation. A 4-year-old girl was referred to our hospital because of abdominal distention and tenderness. A computed tomography (CT scan showed a large tumor occupying the left 3 segments of the liver with tumor thrombus extending into the right atrium. There was also a small intrahepatic metastasis in the right lobe of the liver. She was diagnosed with hepatoblastoma on the basis of the results of open biopsy. Neoadjuvant chemotherapy with an intense CDDP-based regimen was performed. The tumor responded well to chemotherapy, and intrahepatic metastasis became undetectable on CT scan, although the tumor thrombus remained in the right atrium. After 7 courses of chemotherapy, we performed resection using extracorporeal circulation. The postoperative course was uneventful, and adjuvant chemotherapy was started 10 days after the operation. Her serum alpha-fetoprotein (AFP level decreased to the normal range, and she was free of disease for 1 year after the operation. Tumor resection using extracorporeal circulation can be performed safely and is justified in patients with intraatrial tumor thrombus.
-
Vakhitov, Damir; Tuomisto, Sari; Martiskainen, Mika; Korhonen, Janne; Pessi, Tanja; Salenius, Juha-Pekka; Suominen, Velipekka; Lehtimäki, Terho; Karhunen, Pekka J; Oksala, Niku
2018-06-01
Increasing data supports the role of bacterial inflammation in adverse events of cardiovascular and cerebrovascular diseases. In our previous research, DNA of bacterial species found in coronary artery thrombus aspirates and ruptured cerebral aneurysms were mostly of endodontic and periodontal origin, where Streptococcus mitis group DNA was the most common. We hypothesized that the genomes of S mitis group could be identified in thrombus aspirates of patients with lower limb arterial and deep venous thrombosis. Thrombus aspirates and control blood samples taken from 42 patients with acute or acute-on-chronic lower limb ischemia (Rutherford I-IIb) owing to arterial or graft thrombosis (n = 31) or lower limb deep venous thrombosis (n = 11) were examined using a quantitative real-time polymerase chain reaction to detect all possible bacterial DNA and DNA of S mitis group in particular. The samples were considered positive, if the amount of bacterial DNA in the thrombus aspirates was 2-fold or greater in comparison with control blood samples. In the positive samples the mean difference for the total bacterial DNA was 12.1-fold (median, 7.1), whereas the differences for S mitis group DNA were a mean of 29.1 and a median of 5.2-fold. Of the arterial thrombus aspirates, 57.9% were positive for bacterial DNA, whereas bacterial genomes were found in 75% of bypass graft thrombosis with 77.8% of the prosthetic grafts being positive. Of the deep vein thrombus aspirates, 45.5% contained bacterial genomes. Most (80%) of bacterial DNA-positive cases contained DNA from the S mitis group. Previous arterial interventions were significantly associated with the occurrence of S mitis group DNA (P = .049, Fisher's exact test). This is the first study to report the presence of bacterial DNA, predominantly of S mitis group origin, in the thrombus aspirates of surgical patients with lower limb arterial and deep venous thrombosis, suggesting their possible role in the pathogenesis of
-
Heterogeneity of rabbit platelets
International Nuclear Information System (INIS)
Karpatkin, S.
1978-01-01
Rabbits were injected intravenously with a cohort platelet label, 75 Se-selenomethionine. Platelet-rich plasma was separated into five different platelet density fractions on each of seven days by repetitively centrifuging the same sample of platelet-rich plasma at increasing gravitational force. The heaviest platelet sediment fraction was enriched with larger platelets. The lightest platelet sediment fraction was enriched with smaller platelets. Incorporation of isotope into the heaviest platelet fraction was considerably greater than incorporation into the lightest platelet fraction. The mean platelet survival of the lightest two fractions was significantly shorter than that of the heaviest three fractions. SDS-polyacrylamide gel electrophoresis of the platelet cell sap generally revealed 10 prominent protein bands for the heaviest platelet fractions. The lightest platelet fraction had six absent to markedly diminished platelet proteins. The data are compatible with two models, (1) heavy-large platelets are, on average, young platelets which become lighter-smaller platelets while losing platelet membranes and cell sap components with time. (2) Heavy-large platelets and light-small platelets are produced independently by specific megakarocytes. The heavy-large platelets incorporate more isotope that lighter-smaller platelets (possibly because of their megakarocyte precursor). However, they are released earlier into the circulation than lighter-smaller platelets and are therefore younger platelets. The light-smaller platelets which are released later into the circulation have a shorter survival. (author)
-
Emerging Evidence for Platelets as Immune and Inflammatory Effector Cells
Directory of Open Access Journals (Sweden)
Matthew Thomas Rondina
2014-12-01
Full Text Available While traditionally recognized for their roles in hemostatic pathways, emerging evidence demonstrates that platelets have previously unrecognized, dynamic roles that span the immune continuum. These newly-recognized platelet functions, including the secretion of immune mediators, interactions with endothelial cells, monocytes, and neutrophils, toll-like receptor (TLR mediated responses, and induction of neutrophil extracellular trap (NET formation, bridge thrombotic and inflammatory pathways and contribute to host defense mechanisms against invading pathogens. In this focused review, we highlight several of these emerging aspects of platelet biology and their implications in clinical infectious syndromes.
-
Directory of Open Access Journals (Sweden)
I. I. Patalakh
2018-04-01
Full Text Available Hemostatic balance in blood is affected by numerous factors, including coagulation and fibrinolytic proteins, the wide spectrum of their inhibitors, and blood cells. Since platelets can participate in contradictory processes, they significantly complicate the whole picture. Therefore, nowadays the development of global assays of hemostasis, which can reflect the physiological process of hemostasis and can be used for point-of-care diagnosis of thrombosis, is crucial. This paper outlines a new approach we used to analyze the capabilities of clot waveform analysis tools to distinguish the response of platelet-rich plasma from healthy donors and patients with arterial hypertension caused by stimulation of coagulation and lysis (with exogenous thrombin and recombinant tissue-type plasminogen activator, respectively. In donor plasma, when the clot degradation was accompanied by 40 IU/ml of recombinant tissue-type plasminogen activator, platelets potentiated fibrinolysis more than coagulation, which ultimately shifts the overall balance to a profibrinolytic state. At the same time, for patients with hypertension, platelets, embedded in clot obtained from platelet-rich plasma, showed a weaker ability to stimulate fibrinolysis. The obtained data gives the evidence that platelets can act not only as procoagulants but also as profibrinolytics. By simultaneously amplifying coagulation and fibrinolysis, making their rates comparable, platelets would control plasma procoagulant activity, thereby regulating local hemostatic balance, the size and lifetime of the clot. Moreover, clot waveform analysis may be used to distinguish the effects of platelet-rich plasma on clotting or lysis of fibrin clots in healthy donors and patients with essential hypertension.
-
Directory of Open Access Journals (Sweden)
V Milleret
2011-05-01
Full Text Available Titanium implants are most commonly used for bone augmentation and replacement due to their favorable osseointegration properties. Here, hyperhydrophilic sand-blasted and acid-etched (SBA titanium surfaces were produced by alkali treatment and their responses to partially heparinized whole human blood were analyzed. Blood clot formation, platelet activation and activation of the complement system was analyzed revealing that exposure time between blood and the material surface is crucial as increasing exposure time results in higher amount of activated platelets, more blood clots formed and stronger complement activation. In contrast, the number of macrophages/monocytes found on alkali-treated surfaces was significantly reduced as compared to untreated SBA Ti surfaces. Interestingly, when comparing untreated to modified SBA Ti surfaces very different blood clots formed on their surfaces. On untreated Ti surfaces blood clots remain thin (below 15 mm, patchy and non-structured lacking large fibrin fiber networks whereas blood clots on differentiated surfaces assemble in an organized and layered architecture of more than 30 mm thickness. Close to the material surface most nucleated cells adhere, above large amounts of non-nucleated platelets remain entrapped within a dense fibrin fiber network providing a continuous cover of the entire surface. These findings might indicate that, combined with findings of previous in vivo studies demonstrating that alkali-treated SBA Ti surfaces perform better in terms of osseointegration, a continuous and structured layer of blood components on the blood-facing surface supports later tissue integration of an endosseous implant.
-
Directory of Open Access Journals (Sweden)
Christopher Tennuci
2011-01-01
Full Text Available Introduction. This paper compares different approaches to recanalization in a model of the middle cerebral artery (MCA. Methods. An occlusive thrombus (lamb's blood was introduced into the MCA of a model of the cerebral circulation perfused with Hartmann's solution (80 pulsations/min, mean pressure 90 mm Hg. Three methods of clot retrieval were tested: thrombus aspiration via a 4F catheter (n=26, thrombus aspiration via the GP thrombus aspiration device (GPTAD (n=30, and mechanical thrombectomy via the Solitaire Device (n=30. Results. Recanalization rate was similar for all 3 approaches (62%, 77%, and 85%. Time to recanalization was faster with aspiration devices (41 SD 42 s for 4F and 61 SD 21 s for GPTAD than with the Solitaire (197 SD 64 s P<.05 Kruksal-Wallis. Clot fragmentation was the same in the Solitaire (23% and the GPTAD (23%, but higher with the 4F (53%, P<.05. Conclusion. In this model, thrombus aspiration was faster than mechanical thrombectomy, and similarly effective at recanalization. These results should be confirmed in vivo.
-
Ostrowski, Stanisław; Marcinkiewicz, Anna; Kośmider, Anna; Walczak, Andrzej; Zwoliński, Radosław; Jaszewski, Ryszard
2015-09-01
Approximately 60 000 prosthetic valves are implanted annually in the USA. The risk of prosthesis dysfunction ranges from 0.1% to 4% per year. Prosthesis valve dysfunction is usually caused by a thrombus obstructing the prosthetic discs. However, 10% of prosthetic valves are dysfunctional due to pannus formation, and 12% of prostheses are damaged by both fibrinous and thrombotic components. The authors present two patients with dysfunctional aortic prostheses who were referred for cardiac surgery. Different surgical solutions were used in the treatment of each case. The first patient was a 71-year-old woman whose medical history included arterial hypertension, stable coronary artery disease, diabetes mellitus, chronic obstructive pulmonary disease (COPD), and hypercholesterolemia; she had previously undergone left-sided mastectomy and radiotherapy. The patient was admitted to the Cardiac Surgery Department due to aortic prosthesis dysfunction. Transthoracic echocardiography revealed complete obstruction of one disc and a severe reduction in the mobility of the second. The mean transvalvular gradient was very high. During the operation, pannus covering the discs' surface was found. A biological aortic prosthesis was reimplanted without complications. The second patient was an 87-year-old woman with arterial hypertension, persistent atrial fibrillation, and COPD, whose past medical history included gastric ulcer disease and ischemic stroke. As in the case of the first patient, she was admitted due to valvular prosthesis dysfunction. Preoperative transthoracic echocardiography revealed an obstruction of the posterior prosthetic disc and significant aortic regurgitation. Transesophageal echocardiography and fluoroscopy confirmed the prosthetic dysfunction. During the operation, a thrombus growing around a minor pannus was found. The thrombus and pannus were removed, and normal functionality of the prosthetic valve was restored. Precise and modern diagnostic methods
-
Levi, M. [=Marcel M.; Biemond, B. J.; Sturk, A.; Hoek, J.; ten Cate, J. W.
1991-01-01
We studied the effect of an ionic high osmolar contrast medium (Ioxitalamate), an ionic low osmolar contrast medium (Ioxaglate) and various nonionic low osmolar contrast media (Iopamidol, Iopromide and Iohexol) on thrombus growth in a rabbit jugular vein thrombosis model. Thrombus growth was
-
Early diagnosis of rejection reactions by means of 111In-oxine-labelled thrombocytes
International Nuclear Information System (INIS)
Kolbe, H.; Sinzinger, H.; Angelberger, P.; Leithner, C.; Oesterreichische Studiengesellschaft fuer Atomenergie G.m.b.H., Seibersdorf. Inst. fuer Chemie)
1980-01-01
According to a modified labelling method thrombocytes were treated with 111 In-oxine. In 20 patients, aged 8 to 59 years, the labelled thrombocytes were used for scintiscanning of thrombus formation in the vascular system of transplanted kidneys. In patients with either acute or chronic rejection of the graft an enrichment of labelled thrombocytes was observed in the graft up to 12 hours before the increase of plasma creatinine, whereas patients with functioning grafts did not reveal any accumulation of labelled platelets. Thus scintigraphy with 111 In-oxine-labelled platelets proved to be a sensitive method, which first of all enables an early recognition of acute rejection reactions
-
Reproducibility of Manual Platelet Estimation Following Automated Low Platelet Counts
Directory of Open Access Journals (Sweden)
Zainab S Al-Hosni
2016-11-01
Full Text Available Objectives: Manual platelet estimation is one of the methods used when automated platelet estimates are very low. However, the reproducibility of manual platelet estimation has not been adequately studied. We sought to assess the reproducibility of manual platelet estimation following automated low platelet counts and to evaluate the impact of the level of experience of the person counting on the reproducibility of manual platelet estimates. Methods: In this cross-sectional study, peripheral blood films of patients with platelet counts less than 100 × 109/L were retrieved and given to four raters to perform manual platelet estimation independently using a predefined method (average of platelet counts in 10 fields using 100× objective multiplied by 20. Data were analyzed using intraclass correlation coefficient (ICC as a method of reproducibility assessment. Results: The ICC across the four raters was 0.840, indicating excellent agreement. The median difference of the two most experienced raters was 0 (range: -64 to 78. The level of platelet estimate by the least-experienced rater predicted the disagreement (p = 0.037. When assessing the difference between pairs of raters, there was no significant difference in the ICC (p = 0.420. Conclusions: The agreement between different raters using manual platelet estimation was excellent. Further confirmation is necessary, with a prospective study using a gold standard method of platelet counts.
-
Mean platelet volume and mean platelet volume/platelet count ratio
African Journals Online (AJOL)
Amira M. Elsayed
2016-03-30
Mar 30, 2016 ... The aim of this study was to compare the MPV and mean platelet volume/platelet count ... brain stroke, both in the acute phase and long after disease.17 ... males, while the healthy controls comprised 12 females and 8.
-
Directory of Open Access Journals (Sweden)
Auristela Isabel de Oliveira Ramos
2004-12-01
Full Text Available OBJETIVO: Avaliar a incidência de trombo intracardíaco e de tromboembolismo nos três primeiros meses após a troca valvar por bioprótese e identificar fatores de risco para a formação de trombo. MÉTODO:Incluídos 184 pacientes, entre 15 e 75 anos de idade, submetidos a implante de bioprótese e realizados ecocardiogramas transtorácico e transesofágico (ETE na fase hospitalar, média 8,4±3 dias, e três meses após, média 97,4±21,7 dias. RESULTADOS: Incidência de trombo foi significativamente mais elevada nos pacientes com prótese em posição mitral ou mitroaórtica (21,0% do que em posição aórtica (2,8%, pOBJECTIVE: To assess the incidence of intracardiac thrombus and thromboembolism in the first 3 months after bioprosthetic valve replacement and to identify the risk factors for thrombus formation. METHODS: The study comprised 184 patients, aged between 15 and 75 years, who underwent bioprosthetic valve implantation. Transthoracic and transesophageal (TEE echocardiographies were performed in the in-hospital phase (mean, 8.4±3 days and after 3 months (mean, 97.4±21.7 days. RESULTS: The incidence of thrombus was significantly greater in patients with a prosthesis in the mitral or mitroaortic position (21.0% than in those with a prosthesis in the aortic position (2.8%, P<0.001. The multiple logistic regression identified the prosthesis in the mitral or mitroaortic position as the only independent variable for thrombus formation. On the 3-month follow-up, TEE showed a thrombus in 35 (20.7% of the 169 patients on echocardiographic assessment, 31.7% in mitral patients and 3.1% in aortic patients, P<0.001. In the third month, the multiple logistic regression also identified the prosthesis in the mitral or mitroaortic position as the only independent variable for thrombus formation. During the 3-month follow-up, 3 (1.6% patients died and 8 (4.3% experienced embolic phenomena, all in the cerebral territory. CONCLUSION: The incidence
-
Directory of Open Access Journals (Sweden)
Jens Garbade
2012-01-01
Full Text Available The third generation of left ventricular assist devices (LVADs has been shown to improve outcome and quality of life in patients suffering from acute and chronic heart failure. However, VAD-associated complications are still a challenge in the clinical practice. Here we report the resolution of a mobile thrombus formation in the proximity of the inflow cannula of a third generation of LVADs (HVAD Pump, HeartWare, Inc. in a patient with chronic heart failure 4 months after implantation.
-
International Nuclear Information System (INIS)
Yoshimatsu, Rika; Yamagami, Takuji; Tanaka, Osamu; Miura, Hiroshi; Nishimura, Tsunehiko; Okuda, Kotaro; Hashiba, Mitsuoki
2012-01-01
To retrospectively evaluate the frequency and risk factors for developing thrombus in a systemic vein such as the infrarenal inferior vena cava or the iliac vein, in which a balloon-occluded retrograde transvenous obliteration (B-RTO) catheter was indwelled. Forty-nine patients who underwent B-RTO for gastric varices were included in this study. The B-RTO procedure was performed from the right femoral vein, and the B-RTO catheter was retained overnight in all patients. Pre- and post-procedural CT scans were retrospectively compared in order to evaluate the development of thrombus in the systemic vein in which the catheter was indwelled. Additionally, several variables were analyzed to assess risk factors for thrombus in a systemic vein. In all 49 patients (100%), B-RTO was technically successful, and in 46 patients (94%), complete thrombosis of the gastric varices was achieved. In 6 patients (12%), thrombus developed in the infrarenal inferior vena cava or the right common-external iliac vein. All thrombi lay longitudinally on the right side of the inferior vena cava or the right iliac vein. One of the aforementioned 6 patients required anticoagulation therapy. No symptoms suggestive of pulmonary embolism were observed. Prothrombin time-international normalized ratio and the addition of 5% ethanolamine oleate iopamidol, on the second day, were related to the development of thrombus. Development of a thrombus in a systemic vein such as the inferior vena cava or iliac vein, caused by indwelling of the B-RTO catheter, is relatively frequent. Physicians should be aware of the possibility of pulmonary embolism due to iliocaval thrombosis.
-
International Nuclear Information System (INIS)
Seong, Min Hyun; Kim, Young Hwan; Lee, Sang Kwon; Choi, Jin Soo; Kim, Mi Jeong; Koo, Ja Hyun; Kim, Hyoung Tae; Cho, Won Hyun; Seong, Nak Kwan
2005-01-01
We wanted to assess the technical feasibility and clinical efficacy of the placement and retrieval of a Guenther Tulip filter for the prevention of fatal pulmonary embolism during the management of patients with a free floating thrombus in their inferior vena ca va (IVC). Six patients having a free floating thrombus in their IVC (three patients with an isolated free floating thrombus in the IVC that resulted from immobilization due to traumatic liver injury or cerebral infarction, two patients with coexisting deep vein thrombosis in the left lower extremity that was caused by May-Thurner syndrome, and one patient with coexisting deep vein thrombosis in the right lower extremity that was due to nephrotic syndrome and immobilization after hip joint replacement) underwent placement and retrieval of a Guenther Tulip filter. The placement of the filter was performed through the right internal jugular vein to prevent the risk of detachment of the thrombus during the procedure. Retrieval of filter was performed after the free floating thrombus of the IVC had disappeared on follow-up CT because of anticoagulation therapy, aspiration thrombectomy or catheter directed Urokinase thrombolysis. The Guenther Tulip filter was successfully placed in the IVC in all six patients and it was retrieved after the management of the free floating thrombus. The mean duration of the placement of the filter was 11 days (range:7-25 days). Two patients underwent placement of an iliac vein stent for the management of May-Thurner syndrome. Detachment of the free floating thrombus in the IVC and the subsequent thrombus entrapment in the filter were documented during aspiration thrombectomy or Urokinase thrombolysis in four patients. Recurrent thrombus didn't occur during the follow-up period (range:3-20 months) in five of the six patients. In one patient, a recurrent thrombus due to the discontinuance of anticoagulation therapy was identified at the filter detachment site of the IVC on the follow
-
Directory of Open Access Journals (Sweden)
Singh Ravindra
2009-01-01
Full Text Available Background: Platelet rich plasma-platelet concentrate (PRP-PC, buffy coat poor-platelet concentrate (BC-PC, and apheresis-PC were prepared and their quality parameters were assessed. Study Design: In this study, the following platelet products were prepared: from random donor platelets (i platelet rich plasma - platelet concentrate (PRP-PC, and (ii buffy coat poor- platelet concentrate (BC-PC and (iii single donor platelets (apheresis-PC by different methods. Their quality was assessed using the following parameters: swirling, volume of the platelet concentrate, platelet count, WBC count and pH. Results: A total of 146 platelet concentrates (64 of PRP-PC, 62 of BC-PC and 20 of apheresis-PC were enrolled in this study. The mean volume of PRP-PC, BC-PC and apheresis-PC was 62.30±22.68 ml, 68.81±22.95 ml and 214.05±9.91 ml and ranged from 22-135 ml, 32-133 ml and 200-251 ml respectively. The mean platelet count of PRP-PC, BC-PC and apheresis-PC was 7.6±2.97 x 1010/unit, 7.3±2.98 x 1010/unit and 4.13±1.32 x 1011/unit and ranged from 3.2-16.2 x 1010/unit, 0.6-16.4 x 1010/unit and 1.22-8.9 x 1011/unit respectively. The mean WBC count in PRP-PC (n = 10, BC-PC (n = 10 and apheresis-PC (n = 6 units was 4.05±0.48 x 107/unit, 2.08±0.39 x 107/unit and 4.8±0.8 x 106/unit and ranged from 3.4 -4.77 x 107/unit, 1.6-2.7 x 107/unit and 3.2 - 5.2 x 106/unit respectively. A total of 26 units were analyzed for pH changes. Out of these units, 10 each were PRP-PC and BC-PC and 6 units were apheresis-PC. Their mean pH was 6.7±0.26 (mean±SD and ranged from 6.5 - 7.0 and no difference was observed among all three types of platelet concentrate. Conclusion: PRP-PC and BC-PC units were comparable in terms of swirling, platelet count per unit and pH. As expected, we found WBC contamination to be less in BC-PC than PRP-PC units. Variation in volume was more in BC-PC than PRP-PC units and this suggests that further standardization is required for preparation of BC
-
Exposure to acrolein by inhalation causes platelet activation
International Nuclear Information System (INIS)
Sithu, Srinivas D.; Srivastava, Sanjay; Siddiqui, Maqsood A.; Vladykovskaya, Elena; Riggs, Daniel W.; Conklin, Daniel J.; Haberzettl, Petra; O'Toole, Timothy E.; Bhatnagar, Aruni; D'Souza, Stanley E.
2010-01-01
Acrolein is a common air pollutant that is present in high concentrations in wood, cotton, and tobacco smoke, automobile exhaust and industrial waste and emissions. Exposure to acrolein containing environmental pollutants such as tobacco smoke and automobile exhaust has been linked to the activation of the coagulation and hemostasis pathways and thereby to the predisposition of thrombotic events in human. To examine the effects of acrolein on platelets, adult male C57Bl/6 mice were subjected acute (5 ppm for 6 h) or sub-chronic (1 ppm, 6 h/day for 4 days) acrolein inhalation exposures. The acute exposure to acrolein did not cause pulmonary inflammation and oxidative stress, dyslipidemia or induce liver damage or muscle injury. Platelet GSH levels in acrolein-exposed mice were comparable to controls, but acrolein-exposure increased the abundance of protein-acrolein adducts in platelets. Platelets isolated from mice, exposed to both acute and sub-chronic acrolein levels, showed increased ADP-induced platelet aggregation. Exposure to acrolein also led to an increase in the indices of platelet activation such as the formation of platelet-leukocyte aggregates in the blood, plasma PF4 levels, and increased platelet-fibrinogen binding. The bleeding time was decreased in acrolein exposed mice. Plasma levels of PF4 were also increased in mice exposed to environmental tobacco smoke. Similar to inhalation exposure, acrolein feeding to mice also increased platelet activation and established a pro-thrombotic state in mice. Together, our data suggest that acrolein is an important contributing factor to the pro-thrombotic risk in human exposure to pollutants such as tobacco smoke or automobile exhaust, or through dietary consumption.
-
Exposure to acrolein by inhalation causes platelet activation
Energy Technology Data Exchange (ETDEWEB)
Sithu, Srinivas D [Department of Physiology and Biophysics, University of Louisville, Louisville, KY 40202 (United States); Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); Srivastava, Sanjay; Siddiqui, Maqsood A; Vladykovskaya, Elena; Riggs, Daniel W; Conklin, Daniel J; Haberzettl, Petra; O' Toole, Timothy E; Bhatnagar, Aruni [Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); D' Souza, Stanley E., E-mail: sedsou01@louisville.ed [Department of Physiology and Biophysics, University of Louisville, Louisville, KY 40202 (United States)
2010-10-15
Acrolein is a common air pollutant that is present in high concentrations in wood, cotton, and tobacco smoke, automobile exhaust and industrial waste and emissions. Exposure to acrolein containing environmental pollutants such as tobacco smoke and automobile exhaust has been linked to the activation of the coagulation and hemostasis pathways and thereby to the predisposition of thrombotic events in human. To examine the effects of acrolein on platelets, adult male C57Bl/6 mice were subjected acute (5 ppm for 6 h) or sub-chronic (1 ppm, 6 h/day for 4 days) acrolein inhalation exposures. The acute exposure to acrolein did not cause pulmonary inflammation and oxidative stress, dyslipidemia or induce liver damage or muscle injury. Platelet GSH levels in acrolein-exposed mice were comparable to controls, but acrolein-exposure increased the abundance of protein-acrolein adducts in platelets. Platelets isolated from mice, exposed to both acute and sub-chronic acrolein levels, showed increased ADP-induced platelet aggregation. Exposure to acrolein also led to an increase in the indices of platelet activation such as the formation of platelet-leukocyte aggregates in the blood, plasma PF4 levels, and increased platelet-fibrinogen binding. The bleeding time was decreased in acrolein exposed mice. Plasma levels of PF4 were also increased in mice exposed to environmental tobacco smoke. Similar to inhalation exposure, acrolein feeding to mice also increased platelet activation and established a pro-thrombotic state in mice. Together, our data suggest that acrolein is an important contributing factor to the pro-thrombotic risk in human exposure to pollutants such as tobacco smoke or automobile exhaust, or through dietary consumption.
-
In vivo evaluation of titanium-prepared platelet-rich fibrin (T-PRF): a new platelet concentrate.
Tunalı, Mustafa; Özdemir, Hakan; Küçükodacı, Zafer; Akman, Serhan; Fıratlı, Erhan
2013-07-01
We have developed a new, titanium-prepared, platelet-rich fibrin (T-PRF) together with the protocol for forming it, which is based on the hypothesis that titanium tubes may be more effective at activating platelets than the glass tubes used by Chouckroun in his platelet-rich fibrin (PRF) method. The aim of this study was to find a suitable animal model in which to evaluate the method and to investigate the efficacy of T-PRF for wound healing. Blood samples from 6 rabbits were used to confirm the protocol for formation of T-PRF. We evaluated T-PRF or T-PRF-like clots morphologically using scanning electron microscopy (EM). Blood samples from 5 rabbits were used to develop an experiment in which to evaluate the effects of T-PRF on wound healing. The mucoperiosteal flaps were filled with autologous T-PRF membranes from the vestibule in the anterior mandibular regions. Samples collected from the surgical sites were stained with haematoxylin and eosin. We found a mature fibrin network in T-PRF clots that had been centrifuged for 15 min at 3500 rpm and, 15 days after placement of the membrane, we found newly-forming connective tissue and islets of bony tissue in the T-PRF membrane. These results show that T-PRF could induce the formation of new bone with new connective tissue in a rabbit model of wound healing within 30 days of treatment. Published by Elsevier Ltd.
-
Directory of Open Access Journals (Sweden)
Dominik von Elverfeldt
Full Text Available BACKGROUND: Early and non-invasive detection of platelets on micro atherothrombosis provides a means to identify unstable plaque and thereby allowing prophylactic treatment towards prevention of stroke or myocardial infarction. Molecular magnetic resonance imaging (mMRI of activated platelets as early markers of plaque rupture using targeted contrast agents is a promising strategy. In this study, we aim to specifically image activated platelets in murine atherothrombosis by in vivo mMRI, using a dedicated animal model of plaque rupture. METHODS: An antibody targeting ligand-induced binding sites (LIBS on the glycoprotein IIb/IIIa-receptor of activated platelets was conjugated to microparticles of iron oxide (MPIO to form the LIBS-MPIO contrast agent causing a signal-extinction in T2*-weighted MRI. ApoE(-/- mice (60 weeks-old were fed a high fat diet for 5 weeks. Using a small needle, the surface of their carotid plaques was scratched under blood flow to induce atherothrombosis. In vivo 9.4 Tesla MRI was performed before and repetitively after intravenous injection of either LIBS-MPIO versus non-targeted-MPIO. RESULTS: LIBS-MPIO injected animals showed a significant signal extinction (p<0.05 in MRI, corresponding to the site of plaque rupture and atherothrombosis in histology. The signal attenuation was effective for atherothrombosis occupying ≥ 2% of the vascular lumen. Histology further confirmed significant binding of LIBS-MPIO compared to control-MPIO on the thrombus developing on the surface of ruptured plaques (p<0.01. CONCLUSION: in vivo mMRI detected activated platelets on mechanically ruptured atherosclerotic plaques in ApoE(-/- mice with a high sensititvity. This imaging technology represents a unique opportunity for noninvasive detection of atherothrombosis and the identification of unstable atherosclerotic plaques with the ultimate promise to prevent strokes and myocardial infarctions.
-
Wang, Zhifa; Weng, Yanming; Lu, Shengjun; Zong, Chunlin; Qiu, Jianyong; Liu, Yanpu; Liu, Bin
2015-08-01
To analyze the effects of platelet-rich fibrin (PRF) on mesenchymal stem cells (MSCs) in vitro and investigate in vivo bone formation by MSC sheets with PRF. Cell proliferation and expression of osteogenesis-related genes within MSC sheets were assessed upon exposure to PRF from the same donors. We then injected MSC sheet fragments with or without PRF subcutaneously in nude mice and assessed bone formation by micro-computed tomography and histological analyses. PRF significantly stimulated MSC proliferation and osteogenesis in vitro. MSC sheets injected with or without PRF formed new bone, but those with PRF produced significantly more and denser bone. MSC sheets can be used to generate tissue engineered bone upon injection, and PRF increases the osteogenic capacity of MSC sheets in vitro and in vivo. © 2014 Wiley Periodicals, Inc.
-
Erythrocyte membrane modified janus polymeric motors for thrombus therapy
Shao, Jingxin; Abdelghani, Mona; Shen, Guizhi; Cao, Shoupeng; Williams, David S.; van Hest, Jan C.M.
2018-01-01
We report the construction of erythrocyte membrane-cloaked Janus polymeric motors (EM-JPMs) which are propelled by near-infrared (NIR) laser irradiation and are successfully applied in thrombus ablation. Chitosan (a natural polysaccharide with positive charge, CHI) and heparin (glycosaminoglycan
-
Luther, Natascha; Shahneh, Fatemeh; Brähler, Melanie; Krebs, Franziska; Jäckel, Sven; Subramaniam, Saravanan; Stanger, Christian; Schönfelder, Tanja; Kleis-Fischer, Bettina; Reinhardt, Christoph; Probst, Hans Christian; Wenzel, Philip; Schäfer, Katrin; Becker, Christian
2016-12-09
Immune cells play an important role during the generation and resolution of thrombosis. T cells are powerful regulators of immune and nonimmune cell function, however, their role in sterile inflammation in venous thrombosis has not been systematically examined. This study investigated the recruitment, activation, and inflammatory activity of T cells in deep vein thrombosis and its consequences for venous thrombus resolution. CD4 + and CD8 + T cells infiltrate the thrombus and vein wall rapidly on deep vein thrombosis induction and remain in the tissue throughout the thrombus resolution. In the vein wall, recruited T cells largely consist of effector-memory T (T EM ) cells. Using T-cell receptor transgenic reporter mice, we demonstrate that deep vein thrombosis-recruited T EM receive an immediate antigen-independent activation and produce IFN-γ (interferon) in situ. Mapping inflammatory conditions in the thrombotic vein, we identify a set of deep vein thrombosis upregulated cytokines and chemokines that synergize to induce antigen-independent IFN-γ production in CD4 + and CD8 + T EM cells. Reducing the number of T EM cells through a depletion recovery procedure, we show that intravenous T EM activation determines neutrophil and monocyte recruitment and delays thrombus neovascularization and resolution. Examining T-cell recruitment in human venous stasis, we show that superficial varicose veins preferentially contain activated memory T cells. T EM orchestrate the inflammatory response in venous thrombosis affecting thrombus resolution. © 2016 American Heart Association, Inc.
-
Further studies on the relationship between platelet buoyant density and platelet age
International Nuclear Information System (INIS)
Boneu, B.; Vigoni, F.; Boneu, A.; Caranobe, C.; Sie, P.
1982-01-01
The relationship between platelet buoyant density and platelet age was investigated in eight human subjects submitted to an autologous chromium labeled platelet survival study. Platelets were isolated after isopycnic centrifugation using eight discontinuous isoosmotic stractan gradients (five subjects), or various continuous and linear isoosmolar gradients (three subjects). A paradoxical radioactivity enrichment of the dense platelets and a premature loss of radioactivity in the light platelets were observed. These results are explained by a shift of the radioactivity distribution curve toward higher densities during the 3-4 days after platelet injection, while the standard deviation of the distribution was conserved throughout the platelet life span. These results suggest that young platelets are heterogeneous and slightly less dense than the total platelet population
-
The melding of nanomedicine in thrombosis imaging and treatment: a review
Karagkiozaki, Varvara; Pappa, Foteini; Arvaniti, Despoina; Moumkas, Anestis; Konstantinou, Dimitrios; Logothetidis, Stergios
2016-01-01
Thromboembolic diseases constitute a plague in our century, wherein an imbalance of hemostasis leads to thrombus formation and vessels constriction reducing blood flow. Hence, the recent rise of nanomedicine gives birth to advanced diagnostic modalities and therapeutic agents for the early diagnosis and treatment of such diseases. Multimodal nanoagents for the detection of intravascular thrombi and nanovehicles for thrombus-targeted fibrinolytic therapy are few paradigms of nanomedicine approaches to overcome current diagnostic treatment roadblocks and persistent clinical needs. This review highlights the nanomedicine strategies to improve the imaging and therapy of acute thrombi by nanoparticles and nanotheranostics, the detailed imaging of thrombogenic proteins and platelets via atomic force microscopy with the knowledge basis of thrombosis pathophysiology and nanotoxicity. PMID:28031960
-
Insomnia, platelet serotonin and platelet monoamine oxidase in chronic alcoholism.
Nenadic Sviglin, Korona; Nedic, Gordana; Nikolac, Matea; Mustapic, Maja; Muck-Seler, Dorotea; Borovecki, Fran; Pivac, Nela
2011-08-18
Insomnia is a common sleep disorder frequently occurring in chronic alcoholic patients. Neurobiological basis of insomnia, as well as of alcoholism, is associated with disrupted functions of the main neurotransmitter systems, including the serotonin (5-hydroxytryptamine, 5-HT) system. Blood platelets are considered a limited peripheral model for the central 5-HT neurons, since both platelets and central 5-HT synaptosomes have similar dynamics of 5-HT. Platelet 5-HT concentration and platelet monoamine oxidase type B (MAO-B) are assumed to represent biomarkers for particular symptoms and behaviors in psychiatric disorders. The hypothesis of this study was that platelet 5-HT concentration and platelet MAO-B activity will be altered in chronic alcoholic patients with insomnia compared to comparable values in patients without insomnia. The study included 498 subjects: 395 male and 103 female medication-free patients with alcohol dependence and 502 healthy control subjects: 325 men and 177 women. The effects of early, middle and late insomnia (evaluated using the Hamilton Depression Rating Scale), as well as sex, age and smoking on platelet 5-HT concentration and platelet MAO-B activity were evaluated using one-way ANOVA and multiple regression analysis by the stepwise method. Platelet 5-HT concentration, but not platelet MAO-B activity, was significantly reduced in alcoholic patients with insomnia compared to patients without insomnia. Multiple regression analysis revealed that platelet 5-HT concentration was affected by middle insomnia, smoking and sex, while platelet MAO activity was affected only by sex and age. The present and previous data suggest that platelet 5-HT concentration might be used, after controlling for sex and smoking, as a biomarker for insomnia in alcoholism, PTSD and in rotating shift workers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
-
Multisite Thrombus Imaging and Fibrin Content Estimation With a Single Whole-Body PET Scan in Rats.
Blasi, Francesco; Oliveira, Bruno L; Rietz, Tyson A; Rotile, Nicholas J; Naha, Pratap C; Cormode, David P; Izquierdo-Garcia, David; Catana, Ciprian; Caravan, Peter
2015-10-01
Thrombosis is a leading cause of morbidity and mortality worldwide. Current diagnostic strategies rely on imaging modalities that are specific for distinct vascular territories, but a thrombus-specific whole-body imaging approach is still missing. Moreover, imaging techniques to assess thrombus composition are underdeveloped, although therapeutic strategies may benefit from such technology. Therefore, our goal was to test whether positron emission tomography (PET) with the fibrin-binding probe (64)Cu-FBP8 allows multisite thrombus detection and fibrin content estimation. Thrombosis was induced in Sprague-Dawley rats (n=32) by ferric chloride application on both carotid artery and femoral vein. (64)Cu-FBP8-PET/CT imaging was performed 1, 3, or 7 days after thrombosis to detect thrombus location and to evaluate age-dependent changes in target uptake. Ex vivo biodistribution, autoradiography, and histopathology were performed to validate imaging results. Arterial and venous thrombi were localized on fused PET/CT images with high accuracy (97.6%; 95% confidence interval, 92-100). A single whole-body PET/MR imaging session was sufficient to reveal the location of both arterial and venous thrombi after (64)Cu-FBP8 administration. PET imaging showed that probe uptake was greater in younger clots than in older ones for both arterial and venous thrombosis (P<0.0001). Quantitative histopathology revealed an age-dependent reduction of thrombus fibrin content (P<0.001), consistent with PET results. Biodistribution and autoradiography further confirmed the imaging findings. We demonstrated that (64)Cu-FBP8-PET is a feasible approach for whole-body thrombus detection and that molecular imaging of fibrin can provide, noninvasively, insight into clot composition. © 2015 American Heart Association, Inc.
-
George, Mitchell J; Bynum, James; Nair, Prajeeda; Cap, Andrew P; Wade, Charles E; Cox, Charles S; Gill, Brijesh S
2018-07-01
The purpose of this review is to explore the relationship between platelet bioenergetics and biomechanics and how this relationship affects the clinical interpretation of platelet function devices. Recent experimental and technological advances highlight platelet bioenergetics and biomechanics as alternative avenues for collecting clinically relevant data. Platelet bioenergetics drive energy production for key biomechanical processes like adhesion, spreading, aggregation, and contraction. Platelet function devices like thromboelastography, thromboelastometry, and aggregometry measure these biomechanical processes. Platelet storage, stroke, sepsis, trauma, or the activity of antiplatelet drugs alters measures of platelet function. However, the specific mechanisms governing these alterations in platelet function and how they relate to platelet bioenergetics are still under investigation.
-
Posner, M.G; Upadhyay, A.; Abubaker, A.A.; Fortunato, T.M.; Vara, D.; Canobbio, I.; Bagby, S.; Pula, G.
2016-01-01
Extracellular fibrinogen-binding protein (Efb) from Staphylococcus aureus inhibits platelet activation, although its mechanism of action has not been established. In this study, we discovered that the N-terminal region of Efb (Efb-N) promotes platelet binding of fibrinogen and that Efb-N binding to
-
Platelets and their chemokines in atherosclerosis – clinical applications
Directory of Open Access Journals (Sweden)
Philipp evon Hundelshausen
2014-08-01
Full Text Available The concept of platelets as important players in the process of atherogenesis has become increasingly accepted due to accumulating experimental and clinical evidence. Despite the progress in understanding the molecular details of atherosclerosis, particularly by using animal models, the inflammatory and thrombotic roles of activated platelet s especially in the human system remain difficult to dissect, as often only the complications of atherosclerosis i.e. stroke and myocardial infarction are definable but not the plaque burden.Platelet indices including platelet count and mean platelet volume and soluble mediators released by activated platelets are associated with atherosclerosis. The chemokine CXCL4 has multiple atherogenic activities e.g. altering the differentiation of T cells and macrophages by inhibiting neutrophil and monocyte apoptosis and by increasing the uptake of oxLDL and synergizing with CCL5. CCL5 is released and deposited on endothelium by activated platelets thereby triggering atherogenic monocyte recruitment, which can be attenuated by blocking the corresponding chemokine receptor CCR5. Atheroprotective and plaque stabilizing properties are attributed to CXCL12, which plays an important role in regenerative processes by attracting progenitor cells. Its release from luminal attached platelets accelerates endothelial healing after injury. Platelet surface molecules GPIIb/IIIa, GP1bα, P-selectin, JAM-A and the CD40/CD40L dyade are crucially involved in the interaction with endothelial cells, leukocytes and matrix molecules affecting atherogenesis. Beyond the effects on the arterial inflammatory infiltrate, platelets affect cholesterol metabolism by binding, modifying and endocytosing LDL particles via their scavenger receptors and contribute to the formation of lipid laden macrophages. Current medical therapies for the prevention of atherosclerotic therapies enable the elucidation of mechanisms linking platelets to inflammation
-
... Patient Resources For Health Professionals Subscribe Search Platelet Function Tests Send Us Your Feedback Choose Topic At ... Also Known As Platelet Aggregation Studies PFT Platelet Function Assay PFA Formal Name Platelet Function Tests This ...
-
International Nuclear Information System (INIS)
Blank, M.L.; Lee, T.; Cress, E.A.; Malone, B.; Fitzgerald, V.; Snyder, F.
1984-01-01
The metabolic pathway for 1-alkyl-2-acetyl-sn-glycerols, a recently discovered biologically active neutral lipid class, was elucidated in experiments conducted with rabbit platelets. The total lipid extract obtained from platelets incubated with 1-[1-,2- 3 H]alkyl-2-acetyl-sn-glycerols or 1-alkyl-2-[ 3 H]acetyl-sn-glycerols contained at least six metabolic products. The six metabolites, identified on the basis of chemical and enzymatic reactions combined with thin-layer or high-performance liquid chromatographic analyses, corresponded to 1-alkyl-sn-glycerols, 1-alkyl-2-acetyl-sn-glycero-3-phosphates, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acetyl-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphocholines, and 1-alkyl-2-actyl-sn-glycero-3-phosphocholines (platelet activating factor). These results indicate that the metabolic pathway for alkylacetylglycerols involves reaction steps catalyzed by the following enzymatic activities: choline- and ethanolamine- phosphotransferases, acetyl-hydrolase, an acyltransferase, and a phosphotransferase. The step responsible for the biosynthesis of platelet activating factor would appear to be the most important reaction in this pathway and this product could explain the hypotensive activities previously described for alkylacetyl-(or propionyl)-glycerols. Of particular interest was the preference exhibited for the utilization of the 1-hexadecyl-2-acetyl-sn-glycerol species in the formation of platelet activating factor
-
Platelet-rich fibrin in the treatment of periodontal bone defects.
Ranganathan, Aravindhan T; Chandran, Chitraa R
2014-05-01
Periodontitis is characterized by the formation of true pockets, bone loss and attachment loss. Various techniques have been attempted in the past to truly regenerate the lost periodontal structures, albeit with variable outcome. In this evolution, the technique being tried out widely is the use of platelet rich concentrates, namely platelet-rich fibrin (PRF). In this report, we present a case of surgical treatment of osseous bone defects namely two walled crater and dehiscence treated in posterior teeth with autologously prepared platelet rich fibrin mixed with hydroxy apatite bone graft and PRF in the form of a membrane. Our results showed clinical improvements in all the clinical parameters postoperatively namely the pocket depth reduction and gain in attachment level and hence, PRF can be used alone or in combination with the bone graft to yield successful clinical results in treating periodontal osseous defects. Platelet-rich fibrin is an effective alternative to platelet-rich plasma (PRP) in reconstructing bone defects.
-
Marcinkiewicz, Anna; Kośmider, Anna; Walczak, Andrzej; Zwoliński, Radosław; Jaszewski, Ryszard
2015-01-01
Introduction Approximately 60 000 prosthetic valves are implanted annually in the USA. The risk of prosthesis dysfunction ranges from 0.1% to 4% per year. Prosthesis valve dysfunction is usually caused by a thrombus obstructing the prosthetic discs. However, 10% of prosthetic valves are dysfunctional due to pannus formation, and 12% of prostheses are damaged by both fibrinous and thrombotic components. The authors present two patients with dysfunctional aortic prostheses who were referred for cardiac surgery. Different surgical solutions were used in the treatment of each case. Case study 1 The first patient was a 71-year-old woman whose medical history included arterial hypertension, stable coronary artery disease, diabetes mellitus, chronic obstructive pulmonary disease (COPD), and hypercholesterolemia; she had previously undergone left-sided mastectomy and radiotherapy. The patient was admitted to the Cardiac Surgery Department due to aortic prosthesis dysfunction. Transthoracic echocardiography revealed complete obstruction of one disc and a severe reduction in the mobility of the second. The mean transvalvular gradient was very high. During the operation, pannus covering the discs’ surface was found. A biological aortic prosthesis was reimplanted without complications. Case study 2 The second patient was an 87-year-old woman with arterial hypertension, persistent atrial fibrillation, and COPD, whose past medical history included gastric ulcer disease and ischemic stroke. As in the case of the first patient, she was admitted due to valvular prosthesis dysfunction. Preoperative transthoracic echocardiography revealed an obstruction of the posterior prosthetic disc and significant aortic regurgitation. Transesophageal echocardiography and fluoroscopy confirmed the prosthetic dysfunction. During the operation, a thrombus growing around a minor pannus was found. The thrombus and pannus were removed, and normal functionality of the prosthetic valve was restored
-
International Nuclear Information System (INIS)
Peerschke, E.I.
1991-01-01
Previous studies indicated a correlation between the formation of EDTA-resistant (irreversible) platelet-fibrinogen interactions and platelet cytoskeleton formation. The present study explored the direct association of membrane-bound fibrinogen with the Triton X-100 insoluble cytoskeleton of aspirin-treated, gel-filtered platelets, activated but not aggregated with 20 mumol/L adenosine diphosphate (ADP) or 150 mU/mL human thrombin (THR) when bound fibrinogen had become resistant to dissociation by EDTA. Conversion of exogenous 125I-fibrinogen to fibrin was prevented by adding Gly-Pro-Arg and neutralizing THR with hirudin before initiating binding studies. After 60 minutes at 22 degrees C, the cytoskeleton of ADP-treated platelets contained 20% +/- 12% (mean +/- SD, n = 14) of membrane-bound 125I-fibrinogen, representing 10% to 50% of EDTA-resistant fibrinogen binding. The THR-activated cytoskeleton contained 45% +/- 15% of platelet bound fibrinogen, comprising 80% to 100% of EDTA-resistant fibrinogen binding. 125I-fibrinogen was not recovered with platelet cytoskeletons if binding was inhibited by the RGDS peptide, excess unlabeled fibrinogen, or disruption of the glycoprotein (GP) IIb-IIIa complex by EDTA-treatment. Both development of EDTA-resistant fibrinogen binding and fibrinogen association with the cytoskeleton were time dependent and reached maxima 45 to 60 minutes after fibrinogen binding to stimulated platelets. Although a larger cytoskeleton formed after platelet stimulation with thrombin as compared with ADP, no change in cytoskeleton composition was noted with development of EDTA-resistant fibrinogen binding
-
Directory of Open Access Journals (Sweden)
Ivo Volf
2013-05-01
Full Text Available Platelets and lipoproteins play a crucial role in atherogenesis, in part by their ability to modulate inflammation and oxidative stress. While oxidized low density lipoproteins (OxLDL play a central role in the development of this disease, high density lipoproteins (HDL represent an atheroprotective factor of utmost importance. As platelet function is remarkably sensitive to the influence of plasma lipoproteins, it was the aim of this study to clarify if HDL are able to counteract the stimulating effects of OxLDL with special emphasis on aspects of platelet function that are relevant to inflammation. Therefore, HDL were tested for their ability to interfere with pro-thrombotic and pro-inflammatory aspects of platelet function. We are able to show that HDL significantly impaired OxLDL-induced platelet aggregation and adhesion. In gel-filtered platelets, HDL decreased both the formation of reactive oxygen species and CD40L expression. Furthermore, HDL strongly interfered with OxLDL-induced formation of platelet-neutrophil aggregates in whole blood, suggesting that platelets represent a relevant and sensitive target for HDL. The finding that HDL effectively competed with the binding of OxLDL to the platelet surface might contribute to their atheroprotective and antithrombotic properties.
-
Marcinkiewicz, Cezary; Gerstenhaber, Jonathan A; Sternberg, Mark; Lelkes, Peter I; Feuerstein, Giora
2017-01-01
Thromboembolic events (TEE) underwrite key causes of death in developed countries. While advanced imaging technologies such as computed tomography scans serve to diagnose blood clots during acute cardiovascular events, no such technology is available in routine primary care for TEE risk assessment. Here, we describe an imaging platform technology based on bioengineered fluorescent nanodiamond particles (F-NDPs) functionalized with bitistatin (Bit), a disintegrin that specifically binds to the α IIb β 3 integrin, platelet fibrinogen receptor (PFR) on activated platelets. Covalent linkage of purified Bit to F-NDP was concentration-dependent and saturable, as validated by enzyme-linked immunosorbent assay using specific anti-Bit antibodies. F-NDP-Bit interacted with purified PFR, either in immobilized or soluble form. Lotrafiban, a nonpeptide, α IIb β 3 receptor antagonist, specifically blocked F-NDP-Bit-PFR complex formation. Moreover, F-NDP-Bit specifically binds to activated platelets incorporated into a clot generated by thrombin-activated rat platelet-rich plasma (PRP). Our results suggest that engineered F-NDP-Bit particles could serve as noninvasive, "real-time" optical diagnostics for clots present in blood vessels.
-
Energy Technology Data Exchange (ETDEWEB)
Dauvergne, Christian; Araya, Mario [Department of Cardiology, Clinica Alemana, Santiago (Chile); Uriarte, Polentzi [Department of Cardiology, Instituto Nacional del Torax, Santiago (Chile); Novoa, Oscar; Novoa, Lilian [Department of Cardiology, Clinica Alemana, Santiago (Chile); Maluenda, Gabriel, E-mail: gabrielmaluenda@gmail.com [Department of Cardiology, Clinica Alemana, Santiago (Chile)
2013-01-15
Background: The presence of large thrombus burden in patients presenting with acute myocardial infarction (AMI) is common and associated with poor prognosis. This study aimed to describe the feasibility and safety of the novel ‘mother-in-child’ thrombectomy (MCT) technique in patients presenting with AMI and large thrombus burden undergoing percutaneous coronary intervention (PCI). Methods: We studied 13 patients presenting with AMI who underwent PCI with persistent large intracoronary thrombus after standard thrombectomy. The procedure was performed using a 5 F ‘Heartrail II-ST01’ catheter (Terumo Medical) into a 6 F guiding system. Angiographic assessment of thrombus burden and coronary flow was obtained at baseline, immediately after thrombectomy and at the end of the procedure. Results: The mean age was 55.9 ± 13.0 years and involved mostly males (76.9%). All patients underwent PCI via radial approach. Following MCT Thrombolysis In Myocardial Infarction (TIMI) flow improved by 2 or more degrees in 11 patients (84.5%), while visible angiographic thrombus was reduced in 11 patients (84.5%). In the final angiogram, normal TIMI flow was restored in 11 patients (84.5%), with normal myocardial ‘blush’ in 7 patients (53.8%) and total clearance of a visible thrombus in 7 patients (53.8%). Overall, 6 patients received thrombectomy as ‘stand-alone’ procedure. All patients were discharged alive after a mean of 5.6 ± 2 days. Conclusion: This initial report suggests that significant reduction in thrombus burden and improvement of the coronary flow can be safely achieved in patients presenting with AMI and large thrombus burden by using the novel MCT technique.
-
Cell labelling. Granule and platelet kinetics. Recent concepts
International Nuclear Information System (INIS)
Najean, Y.; Dresch, C.; Dassin, E.
Some unsolved problems are reviewed concerning the lifetime of blood platelets, with special reference to excessive platelet consumption and its possible correction by anti-aggregation agents, in many vascular diseases. Regarding the production of platelets it is considered that the 75 Se-methionine labelling method alone offers a quantitative approach to the process and could be used for the physiological study of thrombopoietic factors. A short chapter is devoted to a survey of the points of agreement and disagreement regarding the lifetime of polynuclear cells and a tentative analysis of the reasons explaining the quite different results obtained with DFP and radiochromium labelling. Finally the methods used to study granule formation are criticized, though it is acknowledged that certain ideas useful in physiopathology have emerged from these different procedures [fr
-
[Platelet function in acute myeloid leukemia. II. Aggregation of isolated platelets].
Zawilska, K; Komarnicki, M; Mańka, B
1978-01-01
In 22 patients with acute myeloid leukaemia (17 cases of myeloblastic leukaemia, 4 cases of myelomonocytic leukaemia and 1 case of undifferentiated-cell leukaemia) platelets were isolated from the plasma by the method of Nicholls and Hampton as modified by Levy-Toledano by centrifugation in albumin gradient. The aim of platelet isolation was their "concentration" in cases of thrombocytopenia to values making possible aggregation tests, and platelet separation from the influence of plasma factors. Then aggregation of isolated platelets caused by ADP was studied. In 16 out of 22 patients a fall of aggregation was observed, with the mean values of aggregation rate and intensity were significantly lower. Parallelly done determinations of aggregating activity released from the platelets by thrombin showed lower values as compared with platelets from healthy subjects. In might be thought, in this connection, that the demonstrated reduction of isolated platelets is associated with a diminution of the nucleotide pool or disturbances of the platelet release reaction. The disturbances of the platelet release reaction. The disturbances of aggregation of isolated platelets and reduction of the aggregating activity were most pronounced in acute myelomonocytic leukaemia.
-
Categorization of aortic aneurysm thrombus morphology by magnetic resonance imaging
DEFF Research Database (Denmark)
de la Motte, Louise; Pedersen, Mads Møller; Thomsen, Carsten
2013-01-01
Magnetic resonance imaging (MRI) has been proposed for qualitative categorization of intraluminal thrombus morphology. We aimed to correlate the qualitative MRI categorization previously described to quantitative measurements of signal intensity and to compare morphological characteristics...
-
Wang, Chiun-Lang; Yang, Po-Sheng; Tsao, Jeng-Ting; Jayakumar, Thanasekaran; Wang, Meng-Jiy; Sheu, Joen-Rong; Chou, Duen-Suey
2018-01-01
Oxygen free radicals have been implicated in the pathogenesis of toxic liver injury and are thought to be involved in cardiac dysfunction in the cirrhotic heart. Therefore, direct evidence for the electron spin resonance (ESR) detection of how D‑galactosamine (GalN), an established experimental hepatotoxic substance, induced free radicals formation in platelets and primary hepatocytes is presented in the present study. ESR results demonstrated that GalN induced hydroxyl radicals (OH•) in a resting human platelet suspension; however, radicals were not produced in a cell free Fenton reaction system. The GalN‑induced OH• formation was significantly inhibited by the cyclooxygenase (COX) inhibitor indomethasin, though it was not affected by the lipoxygenase (LOX) or cytochrome P450 inhibitors, AA861 and 1‑aminobenzotriazole (ABT), in platelets. In addition, the present study demonstrated that baicalein induced semiquinone free radicals in platelets, which were significantly reduced by the COX inhibitor without affecting the formed OH•. In the mouse primary hepatocytes, the formation of arachidonic acid (AA) induced carbon‑centered radicals that were concentration dependently enhanced by GalN. These radicals were inhibited by AA861, though not affected by indomethasin or ABT. In addition, GalN did not induce platelet aggregation prior to or following collagen pretreatment in human platelets. The results of the present study indicated that GalN and baicalein may induce OH• by COX and LOX in human platelets. GalN also potentiated AA induced carbon‑centered radicals in hepatocytes via cytochrome P450. The present study presented the role of free radicals in the pathophysiological association between platelets and hepatocytes.
-
International Nuclear Information System (INIS)
Vahedian, Jalal; Sadeghapour, Ali
2006-01-01
Pseudoaneurysm of the infrarenal aorta due to Behcet s disease is very rare. We report a case of pseudoaneurysm associated with Behcet s disease in a 17-year-old boy with a recurrent right ventricular thrombus successfully treated with revascularization using arterial homograft patch. Echocardiography examination revealed a right ventricular mass, thought to be a thrombus in an unusual location. Postoperatively, the findings of the pathologic examination confirmed the mass as a thrombus. When the patient was subsequently re-admitted to the emergency unit with complaints of severe abdominal pain, fever, fatigue, sinus tachycardia, and a pulsating and tender abdominal mass, a right ventricular thrombus and a large pseudoaneurysm of the abdominal aorta were found on echocardiography and angiography. The patient underwent resection of the aortic aneurysm and aortoplasty, using arterial homograft patch, and received immunosuppressive and anticoagulation therapy. The thrombus of the right ventricle disappeared 4 months later. This case indicates that a right ventricular thrombosis in Behcet s disease may be managed by medical therapy. (author)
-
Fijnheer, R.; Pietersz, R. N.; de Korte, D.; Gouwerok, C. W.; Dekker, W. J.; Reesink, H. W.; Roos, D.
1990-01-01
The activation of platelets during the preparation of platelet concentrates (PCs) by two methods was compared. To eliminate interdonor differences, 2 units of whole blood were pooled and subsequently divided into two batches. From one batch, the platelets were harvested as pelleted platelets from
-
Overview of platelet physiology and laboratory evaluation of platelet function.
Rodgers, G M
1999-06-01
Appropriate laboratory testing for the platelet-type bleeding disorders hinges on an adequate assessment in the history and physical examination. Patients with histories and screening laboratory results consistent with coagulation disorders (hemophilia, disseminated intravascular coagulation) are not appropriate candidates for platelet function testing. In contrast, patients with a lifelong history of platelet-type bleeding symptoms and perhaps a positive family history of bleeding would be appropriate for testing. Figure 6 depicts one strategy to evaluate these patients. Platelet morphology can easily be evaluated to screen for two uncommon qualitative platelet disorders: Bernard-Soulier syndrome (associated with giant platelets) and gray platelet syndrome, a subtype of storage pool disorder in which platelet granulation is morphologically abnormal by light microscopy. If the bleeding disorder occurred later in life (no bleeding with surgery or trauma early in life), the focus should be on acquired disorders of platelet function. For those patients thought to have an inherited disorder, testing for vWD should be done initially because approximately 1% of the population has vWD. The complete vWD panel (factor VIII coagulant activity, vWf antigen, ristocetin cofactor activity) should be performed because many patients will have abnormalities of only one particular panel component. Patients diagnosed with vWD should be classified using multimeric analysis to identify the type 1 vWD patients likely to respond to DDAVP. If vWD studies are normal, platelet aggregation testing should be performed, ensuring that no antiplatelet medications have been ingested at least 1 week before testing. If platelet aggregation tests are normal and if suspicion for an inherited disorder remains high, vWD testing should be repeated. The evaluation of thrombocytopenia may require bone marrow examination to exclude primary hematologic disorders. If future studies with thrombopoietin assays
-
Noulsri, Egarit; Udomwinijsilp, Prapaporn; Lerdwana, Surada; Chongkolwatana, Viroje; Permpikul, Parichart
2017-04-01
There has been an increased interest in platelet-derived microparticles (PMPs) in transfusion medicine. Little is known about PMP status during the preparation of platelet concentrates for transfusion. The aim of this study is to compare the PMP levels in platelet components prepared using the buffy coat (BC), platelet-rich plasma platelet concentrate (PRP-PC), and apheresis (AP) processes. Platelet components were prepared using the PRP-PC and BC processes. Apheresis platelets were prepared using the Trima Accel and Amicus instruments. The samples were incubated with annexin A5-FITC, CD41-PE, and CD62P-APC. At day 1 after processing, the PMPs and activated platelets were determined using flow cytometry. Both the percentage and number of PMPs were higher in platelet components prepared using the Amicus instrument (2.6±1.8, 32802±19036 particles/μL) than in platelet components prepared using the Trima Accel instrument (0.5±0.4, 7568±5298 particles/μL), BC (1.2±0.6, 12,920±6426 particles/μL), and PRP-PC (0.9±0.6, 10731±5514 particles/μL). Both the percentage and number of activated platelets were higher in platelet components prepared using the Amicus instrument (33.2±13.9, 427553±196965 cells/μL) than in platelet components prepared using the Trima Accel instrument (16.2±6.1, 211209±87706 cells/μL), BC (12.9±3.2, 140624±41003 cells/μL), and PRP-PC (21.1±6.3, 265210±86257 cells/μL). The study suggests high variability of PMPs and activated platelets in platelet components prepared using different processes. This result may be important in validating the instruments involved in platelet blood collection and processing. Copyright © 2016 Elsevier Ltd. All rights reserved.
-
Crosstalk between Platelets and the Immune System: Old Systems with New Discoveries
Directory of Open Access Journals (Sweden)
Conglei Li
2012-01-01
Full Text Available Platelets are small anucleate cells circulating in the blood. It has been recognized for more than 100 years that platelet adhesion and aggregation at the site of vascular injury are critical events in hemostasis and thrombosis; however, recent studies demonstrated that, in addition to these classic roles, platelets also have important functions in inflammation and the immune response. Platelets contain many proinflammatory molecules and cytokines (e.g., P-selectin, CD40L, IL-1β, etc., which support leukocyte trafficking, modulate immunoglobulin class switch, and germinal center formation. Platelets express several functional Toll-like receptors (TLRs, such as TLR-2, TLR-4, and TLR-9, which may potentially link innate immunity with thrombosis. Interestingly, platelets also contain multiple anti-inflammatory molecules and cytokines (e.g., transforming growth factor-β and thrombospondin-1. Emerging evidence also suggests that platelets are involved in lymphatic vessel development by directly interacting with lymphatic endothelial cells through C-type lectin-like receptor 2. Besides the active contributions of platelets to the immune system, platelets are passively targeted in several immune-mediated diseases, such as autoimmune thrombocytopenia, infection-associated thrombocytopenia, and fetal and neonatal alloimmune thrombocytopenia. These data suggest that platelets are important immune cells and may contribute to innate and adaptive immunity under both physiological and pathological conditions.
-
Platelets in thrombosis and hemostasis: old topic with new mechanisms.
Wang, Yiming; Andrews, Marc; Yang, Yan; Lang, Sean; Jin, Joseph W; Cameron-Vendrig, Alison; Zhu, Guangheng; Reheman, Adili; Ni, Heyu
2012-12-01
Platelets are small anucleate cells generated from megakaryocytes in the bone marrow. After being released into the circulation, platelets play key roles in the surveillance of vascular injury, and can quickly adhere and aggregate at the site of injury, which are critical events for vascular repair and hemostasis. However, the same biological processes of platelet adhesion and aggregation may also cause thrombotic disorders. The formation of a platelet plug at sites of atherosclerotic lesion rupture is the most common mechanism leading to myocardial or cerebral infarction. Platelet-related deep vein thrombosis is also one of the leading causes of mortality worldwide. The contribution of several platelet receptors and their ligands has been highlighted in these processes. In platelet adhesion, particularly at high shear stress, GPIbα-von Willebrand factor (VWF) interaction may initiate this event, which is followed by GPVI signalling and firm platelet adhesion mediated by members of the integrin family, such as β3 (αIIbβ3) and β1 (α2β1, α5β1) integrins. In platelet aggregation, although GPIbα-VWF, P selectin-sulfatides, and other molecules, may be involved, the process is mainly mediated by β3 (αIIbβ3) integrin and its ligands, such as fibrinogen and VWF. It is intriguing that platelet adhesion and aggregation still occur in mice lacking both fibrinogen and VWF, suggesting that other unforeseen molecule(s) may also be important in these processes. Identification and characterization of these molecules will enrich our knowledge in the basic science of hemostasis and thrombosis, and may lead to the development of new therapies against bleeding disorders and thrombotic diseases.
-
Directory of Open Access Journals (Sweden)
Prerna Ashok Karde
2017-01-01
Full Text Available Background: Platelet concentrates are used in various medical procedures to promote soft- and hard-tissue regeneration. In recent times, their antimicrobial efficacy is also explored. However, various platelet concentrates have evolved which differ in the centrifugation protocols. One such recently introduced platelet concentrate is injectable platelet-rich fibrin (i-PRF concentrate. Hence, the aim was to evaluate the antimicrobial property, and platelet count of i-PRF in comparison to other platelet concentrates, i.e., PRF, platelet-rich plasma (PRP, and control (whole blood. Materials and Methods: Blood samples were obtained from 10 chronic generalized marginal gingivitis patients. Platelet concentrates were prepared using standardized centrifugation protocol. Platelet count was evaluated by manual counting method using smear preparation of each sample. Subsequently, antimicrobial activity against oral bacteria was examined on blood agar using disc diffusion method to quantify the inhibitory effects. Results: Statistical significance was analyzed by one-way analysis of variance (ANOVA. P 0.05. i-PRF showed statistically significant difference (P < 0.001 in platelet count when compared to control. It was also significant when compared to PRP (P < 0.01, PRF (P < 0.001. Conclusion: i-PRF has maximum antimicrobial efficacy and higher platelet count in comparison to other platelet concentrates, thereby indicating to have a better regenerative potential then others.
-
Membrane-associated 41-kDa GTP-binding protein in collagen-induced platelet activation
International Nuclear Information System (INIS)
Walker, G.; Bourguignon, L.Y.
1990-01-01
Initially we established that the binding of collagen to human blood platelets stimulates both the rapid loss of PIP2 and the generation of inositol-4,5-bisphosphate (IP2) and inositol-1,4,5-triphosphate (IP3). These results indicate that the binding of collagen stimulates inositol phospholipid-specific phospholipase C during platelet activation. The fact that GTP or GTP-gamma-S augments, and pertussis toxin inhibits, collagen-induced IP3 formation suggests that a GTP-binding protein or (or proteins) may be directly involved in the regulation of phospholipase C-mediated phosphoinositide turnover in human platelets. We have used several complementary techniques to isolate and characterize a platelet 41-kDa polypeptide (or polypeptides) that has a number of structural and functional similarities to the regulatory alpha i subunit of the GTP-binding proteins isolated from bovine brain. This 41-kDa polypeptide (or polypeptides) is found to be closely associated with at least four membrane glycoproteins (e.g., gp180, gp110, gp95, and gp75) in a 330-kDa complex that can be dissociated by treatment with high salt plus urea. Most important, we have demonstrated that antilymphoma 41-kDa (alpha i subunit of GTP-binding proteins) antibody cross-reacts with the platelet 41-kDa protein (or proteins) and the alpha i subunit of bovine brain Gi alpha proteins, and blocks GTP/collagen-induced IP3 formation. These data provide strong evidence that the 41-kDa platelet GTP-binding protein (or proteins) is directly involved in collagen-induced signal transduction during platelet activation
-
Membrane-associated 41-kDa GTP-binding protein in collagen-induced platelet activation
Energy Technology Data Exchange (ETDEWEB)
Walker, G.; Bourguignon, L.Y. (Univ. of Miami Medical School, FL (USA))
1990-08-01
Initially we established that the binding of collagen to human blood platelets stimulates both the rapid loss of PIP2 and the generation of inositol-4,5-bisphosphate (IP2) and inositol-1,4,5-triphosphate (IP3). These results indicate that the binding of collagen stimulates inositol phospholipid-specific phospholipase C during platelet activation. The fact that GTP or GTP-gamma-S augments, and pertussis toxin inhibits, collagen-induced IP3 formation suggests that a GTP-binding protein or (or proteins) may be directly involved in the regulation of phospholipase C-mediated phosphoinositide turnover in human platelets. We have used several complementary techniques to isolate and characterize a platelet 41-kDa polypeptide (or polypeptides) that has a number of structural and functional similarities to the regulatory alpha i subunit of the GTP-binding proteins isolated from bovine brain. This 41-kDa polypeptide (or polypeptides) is found to be closely associated with at least four membrane glycoproteins (e.g., gp180, gp110, gp95, and gp75) in a 330-kDa complex that can be dissociated by treatment with high salt plus urea. Most important, we have demonstrated that antilymphoma 41-kDa (alpha i subunit of GTP-binding proteins) antibody cross-reacts with the platelet 41-kDa protein (or proteins) and the alpha i subunit of bovine brain Gi alpha proteins, and blocks GTP/collagen-induced IP3 formation. These data provide strong evidence that the 41-kDa platelet GTP-binding protein (or proteins) is directly involved in collagen-induced signal transduction during platelet activation.
-
Platelet-rich fibrin: Evolution of a second-generation platelet concentrate
Directory of Open Access Journals (Sweden)
Sunitha Raja V
2008-01-01
Full Text Available Platelet-rich plasma (PRP is a platelet concentrate that has been used widely to accelerate soft-tissue and hard-tissue healing. The preparation of PRP has been described by several authors. Platelet-rich fibrin (PRF was first described by Choukroun et al. in France. It has been referred to as a second-generation platelet concentrate, which has been shown to have several advantages over traditionally prepared PRP. Its chief advantages include ease of preparation and lack of biochemical handling of blood, which makes this preparation strictly autologous. This article describes the evolution of this novel platelet concentrate, referred to as PRF.
-
International Nuclear Information System (INIS)
Rai, Divyajeet; Velu, Ramesh; Tosenovsky, Patrik; Quigley, Francis; Wisniowski, Brendan; Walker, Philip J.; Bradshaw, Barbara; Golledge, Jonathan
2014-01-01
Aortic calcification and thrombus have been postulated to worsen outcome following endovascular abdominal aortic aneurysm repair (EVAR). The purpose of this study was to assess the association of abdominal aortic aneurysm (AAA) calcification and thrombus volume with outcome following EVAR using a reproducible, quantifiable computed tomography (CT) assessment protocol. Patients with elective EVAR performed between January 2002 and 2012 at the Townsville Hospital, Mater Private Hospital (Townsville) and Royal Brisbane and Women's Hospital (RBWH) were included if preoperative CTAs were available for analysis. AAA calcification and thrombus volume were measured using a semiautomated workstation protocol. Outcomes were assessed in terms of clinical failure, endoleak (type I, type II) and reintervention. Univariate and multivariate analyses were performed. Median follow-up was 1.7 years and the interquartile range 1.0-3.8 years. One hundred thirty-four patients undergoing elective EVAR were included in the study. Rates of primary clinical success and freedom from reintervention were 82.8 % and 88.9 % at the 24-month follow-up. AAA calcification and thrombus volume were not associated with clinical failure, type I endoleak, type II endoleak or reintervention. AAA calcification and thrombus volume were not associated with poorer outcome after EVAR in this study. (orig.)
-
Energy Technology Data Exchange (ETDEWEB)
Rai, Divyajeet; Velu, Ramesh; Tosenovsky, Patrik; Quigley, Francis [James Cook University, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, Townsville, Queensland (Australia); The Townsville Hospital, Department of Vascular and Endovascular Surgery, Douglas (Australia); Wisniowski, Brendan; Walker, Philip J. [James Cook University, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, Townsville, Queensland (Australia); University of Queensland, School of Medicine and Centre for Clinical Research, Department of Vascular Surgery, Royal Brisbane and Women' s Hospital, Herston, QLD (Australia); Bradshaw, Barbara [James Cook University, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, Townsville, Queensland (Australia); Golledge, Jonathan [James Cook University, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine and Dentistry, Townsville, Queensland (Australia); The Townsville Hospital, Department of Vascular and Endovascular Surgery, Douglas (Australia); University of Queensland, School of Medicine and Centre for Clinical Research, Department of Vascular Surgery, Royal Brisbane and Women' s Hospital, Herston, QLD (Australia)
2014-08-15
Aortic calcification and thrombus have been postulated to worsen outcome following endovascular abdominal aortic aneurysm repair (EVAR). The purpose of this study was to assess the association of abdominal aortic aneurysm (AAA) calcification and thrombus volume with outcome following EVAR using a reproducible, quantifiable computed tomography (CT) assessment protocol. Patients with elective EVAR performed between January 2002 and 2012 at the Townsville Hospital, Mater Private Hospital (Townsville) and Royal Brisbane and Women's Hospital (RBWH) were included if preoperative CTAs were available for analysis. AAA calcification and thrombus volume were measured using a semiautomated workstation protocol. Outcomes were assessed in terms of clinical failure, endoleak (type I, type II) and reintervention. Univariate and multivariate analyses were performed. Median follow-up was 1.7 years and the interquartile range 1.0-3.8 years. One hundred thirty-four patients undergoing elective EVAR were included in the study. Rates of primary clinical success and freedom from reintervention were 82.8 % and 88.9 % at the 24-month follow-up. AAA calcification and thrombus volume were not associated with clinical failure, type I endoleak, type II endoleak or reintervention. AAA calcification and thrombus volume were not associated with poorer outcome after EVAR in this study. (orig.)
-
Thrombus Size is Associated with Etiology of Deep Venous Thrombosis – A Cross-Sectional Study
Vučić, Nikša; Magdić, Tihana; Krnić, Anton; Včev, Aleksandar; Božić, Dubravko
2005-01-01
The aim of this study was to evaluate the impact of risk factors for deep vein thrombosis (DVT) on thrombus sizes in lower extremities. The size and extent of thrombus was scored according to International Consensus Committee for venous disease classification. After the diagnosis of DVT was established and its size scored, predominant risk factors for DVT in each patient were identified (malignant disease, thrombophilia, postoperative state, hormonal therapy, heredity, limb trauma, immobiliza...
-
Platelet collection efficiencies of three different platelet-rich plasma preparation systems.
Aydin, Fatma; Pancar Yuksel, Esra; Albayrak, Davut
2015-06-01
Different systems have been used for the preparation of platelet-rich plasma (PRP), but platelet collection efficiencies of these systems are not clear. To evaluate the platelet collection efficiencies of three different PRP preparation systems. Blood samples were obtained from the same 16 volunteers for each system. The samples were centrifuged and PRP was prepared by three systems. The ratio of the total number of platelets in PRP to the total number of platelets of the venous blood sample of the patient expressed in percentage was named as platelet collection efficiency and calculated for each system. Mean platelet collection efficiencies were 66.6 (min: 56.9, max: 76.9), 58.3 (min: 27.3, max: 102.8), 50.8 (min: 27.2, max: 73) for top and bottom bag system, system using citrated tube, and the system using tube with Ficoll and cell extraction kit, respectively. Statistically significant difference was found only between the platelet collection efficiencies of systems using the tube with ficoll and cell extraction kit and the top and bottom bag system (p = 0.002). All three systems could be used for PRP preparation, but top and bottom bag system offers a slight advantage over the system using Ficoll and cell extraction kit regarding the platelet collection efficiency.
-
Towards personalised therapy for von Willebrand disease: a future role for recombinant products.
Favaloro, Emmanuel J
2016-05-01
von Willebrand disease (VWD) is reportedly the most common bleeding disorder and is caused by deficiencies and/or defects in the adhesive plasma protein von Willebrand factor (VWF). Functionally, normal VWF prevents bleeding by promoting both primary and secondary haemostasis. In respect to primary haemostasis, VWF binds to both platelets and sub-endothelial matrix components, especially collagen, to anchor platelets to damaged vascular tissue and promote thrombus formation. VWF also stabilises and protects factor VIII in the circulation, delivering FVIII to the site of injury, which then facilitates secondary haemostasis and fibrin formation/thrombus stabilisation. As a result of this, patients with VWD suffer a bleeding diathesis reflective of a primary defect caused by defective/deficient VWF, which in some patients is compounded by a reduction in FVIII. Management of VWD, therefore, chiefly entails replacement of VWF, and sometimes also FVIII, to protect against bleeding. The current report principally focuses on the future potential for "personalised" management of VWD, given the emerging options in recombinant therapies. Recombinant VWF has been developed and is undergoing clinical trials, and this promising therapy may soon change the way in which VWD is managed. In particular, we can envisage a personalised treatment approach using recombinant VWF, with or without recombinant FVIII, depending on the type of VWD, the extent of deficiencies, and the period and duration of treatment.
-
Evidence that platelet buoyant density, but not size, correlates with platelet age in man
International Nuclear Information System (INIS)
Mezzano, D.; Hwang, K.; Catalano, P.; Aster, R.H.
1981-01-01
Following infusion of 51Cr-labeled autologous platelets into normal subjects, high-density (HD) and low-density (LD) platelet cohorts were isolated by prolonged centrifugation in isosmotic arabino-galactan (Stractan). Specific radio-activity of LD platelets declined rapidly post-infusion (T1/2 . 1.5 days), but specific radioactivity of HD platelets remained constant or increased over a 3--4-day period and gradually declined for 6--7 days thereafter. These differences were exaggerated when platelet cohorts enriched in LD or HD cells by slow centrifugation in high-density albumin were labeled and transfused. Mean survival of a platelet cohort enriched with HD cells was significantly (P less than 0.02) shorter (7.73 days) than that of a cohort enriched with LD cells (9.33) days). In normal subjects treated with aspirin, capacity for thromboxane synthesis was regained more rapidly (P less than 0.05) in LD than in HD platelets. HD and LD platelets differed only slightly in mean volume (HD platelets . 7.57 mu3, LD platelets . 6.87 mu3, 0.05 less than P less than 0.01). We believe the most logical interpretation of these findings is that under normal conditions in man, newly formed platelets are less dense on the average than total platelets and become more dense as they age in the circulation. Thus, specific radioactivity of LD platelets declines rapidly as these platelets move into a more dense compartment and are replaced by newly formed, unlabelled cells; specific radioactivity of HD platelets remains constant or increases as labelled platelets enter this compartment in numbers equal to or greater than the number leaving it at the end of their life span. The similarity in mean volumes of LD and HD platelets suggests that platelet size is unrelated to platelet age under normal conditions
-
Hadjesfandiari, Narges; Weinhart, Marie; Kizhakkedathu, Jayachandran N; Haag, Rainer; Brooks, Donald E
2018-03-01
Platelets have a limited shelf life, due to the risk of bacterial contamination and platelet quality loss. Most platelet storage bags are made of a mixture of polyvinyl chloride with a plasticizer, denoted as pPVC. To improve biocompatibility of pPVC with platelets and to inhibit bacterial biofilm formation, an antifouling polymer coating is developed using mussel-inspired chemistry. A copolymer of N,N-dimethylacrylamide and N-(3-aminopropyl)methacrylamide hydrochloride is synthesized and coupled with catechol groups, named DA51-cat. Under mild aqueous conditions, pPVC is first equilibrated with an anchoring polydopamine layer, followed by a DA51-cat layer. Measurements show this coating decreases fibrinogen adsorption to 5% of the control surfaces. One-step coating with DA51-cat does not coat pPVC efficiently although it is sufficient for coating silicon wafers and gold substrates. The dual layer coating on platelet bags resists bacterial biofilm formation and considerably decreases platelet adhesion. A cationic antimicrobial peptide, E6, is conjugated to DA51-cat then coated on silicon wafers and introduces bactericidal activity to these surfaces. Time-of-flight second ion-mass spectroscopy is successfully applied to characterize these surfaces. pPVC is widely used in medical devices; this method provides an approach to controlling biofouling and bacterial growth on it without elaborate surface modification procedures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
-
Jiang, Jianguang; Tu, Jianfei; Jia, Zhongzhi; Chen, Jiezhong; Cao, Haitao; Meng, Qingli; Fuller, Tyler A; Tian, Feng
2017-01-01
The aim of the study was to retrospectively evaluate the incidence and outcomes of inferior vena cava (IVC) filter thrombus during catheter-directed thrombolysis (CDT) for acute proximal deep venous thrombosis (DVT). From October 2006 to June 2015, patients diagnosed with acute proximal DVT and received CDT after a retrievable IVC filter was placed were included. The incidence, treatment, and outcomes of IVC filter thrombus during CDT were recorded and analyzed. A total of 189 patients (91 women, 98 men; mean age, 57.6 ± 9.8 years; range, 24-85 years) were included in this study. Among the 189 cases, the DVTs involved popliteal iliofemoral veins in 54 patients, iliofemoral veins in 113 patients, and iliac veins in 22 patients, of which 18 patients had thrombus extended into the IVC. Of the 189 patients, a total of 8 (4.2%, 8 of 189) patients were identified with IVC filter thrombus during CDT. The IVC filter thrombus was detected on a median of 2 days (range, 2-4 days) of CDT therapy, including small-size (n = 6) and large-size (n = 2) filter thrombus. Of the 8 patients, CDTs were performed with a mean 7.6 ± 1.1 days (range, 6-11 days) after the presence of symptoms for the treatment of proximal DVT, and all the IVC filter thrombi were lysed during CDT for the proximal DVT. All the IVC filters were removed successfully with a mean of 12.8 ± 0.93 days from placement. There were no procedure- or thrombolysis-related major complications, and no symptomatic pulmonary embolism breakthrough was seen in any of the patients after the filter placement. IVC filter thrombus during CDT for the acute proximal DVT is uncommon, and all of them did not need any additional treatment. Copyright © 2016 Elsevier Inc. All rights reserved.
-
Chi, Gerald; Goldhaber, Samuel Z; Hull, Russell D; Hernandez, Adrian F; Kerneis, Mathieu; Al Khalfan, Fahad; Cohen, Alexander T; Harrington, Robert A; Gibson, C Michael
2017-12-01
Background The aim of this study was to evaluate the effect of betrixaban on the occurrence of deep vein thrombosis (DVT) and also the extent of thrombus and to assess the association of baseline D-dimer with subsequent thrombus burden. Methods In the APEX trial (ClinicalTrials.gov: NCT01583218), 7,513 acutely ill hospitalized medical patients were randomly assigned to extended-duration betrixaban (35–42 days) or enoxaparin (10 ± 4 days). D-dimer concentration was measured at baseline, and mandatory lower-extremity compression ultrasonography (CUS) was performed at 35 to 42 days. The thrombus burden of DVT was assessed by the number of non-compressible vascular segments in six target proximal veins and compared between treatment groups and D-dimer categories (≥2 × upper limit of normal [ULN] versus thrombus burden (p = 0.012 for any-dose and p = 0.001 for full-dose). Elevated D-dimer at baseline was independently associated with a 2.12-fold increased risk of developing DVT (p thrombus burden was also observed in those with D-dimer ≥ 2 × ULN compared with venous segments with thrombosis at 35 to 42 days compared with enoxaparin. A positive D-dimer was associated with a greater extent of thrombus burden among acutely ill medical patients who developed DVT despite receiving thromboprophylaxis.
-
Aluminum induces lipid peroxidation and aggregation of human blood platelets
Directory of Open Access Journals (Sweden)
T.J.C. Neiva
1997-05-01
Full Text Available Aluminum (Al3+ intoxication is thought to play a major role in the development of Alzheimer's disease and in certain pathologic manifestations arising from long-term hemodialysis. Although the metal does not present redox capacity, it can stimulate tissue lipid peroxidation in animal models. Furthermore, in vitro studies have revealed that the fluoroaluminate complex induces diacylglycerol formation, 43-kDa protein phosphorylation and aggregation. Based on these observations, we postulated that Al3+-induced blood platelet aggregation was mediated by lipid peroxidation. Using chemiluminescence (CL of luminol as an index of total lipid peroxidation capacity, we established a correlation between lipid peroxidation capacity and platelet aggregation. Al3+ (20-100 µM stimulated CL production by human blood platelets as well as their aggregation. Incubation of the platelets with the antioxidants nor-dihydroguaiaretic acid (NDGA (100 µM and n-propyl gallate (NPG (100 µM, inhibitors of the lipoxygenase pathway, completely prevented CL and platelet aggregation. Acetyl salicylic acid (ASA (100 µM, an inhibitor of the cyclooxygenase pathway, was a weaker inhibitor of both events. These findings suggest that Al3+ stimulates lipid peroxidation and the lipoxygenase pathway in human blood platelets thereby causing their aggregation
-
Three-dimensional structure and cytokine distribution of platelet-rich fibrin.
Bai, Meng-Yi; Wang, Ching-Wei; Wang, Jyun-Yi; Lin, Ming-Fang; Chan, Wing P
2017-02-01
Previous reports have revealed that several cytokines (including platelet-derived growth factor-BB, transforming growth factors-β1 and insulin-like growth factor-1) can enhance the rate of bone formation and synthesis of extracellular matrix in orthopaedics or periodontology. This study aimed to determine the concentration of cytokines within platelet-rich fibrin microstructures and investigate whether there are differences in the different portions of platelet-rich fibrin, which has implications for proper clinical use of platelet-rich fibrin gel. Whole blood was obtained from six New Zealand rabbits (male, 7 to 39 weeks old, weight 2.7-4 kg); it was then centrifuged for preparation of platelet-rich fibrin gels and harvest of plasma. The resultant platelet-rich fibrin gels were used for cytokine determination, histological analyses and scanning electron microscopy. All plasmas obtained were subject to the same cytokine determination assays for the purpose of comparison. Cytokines platelet-derived growth factor-BB and transforming growth factor-β1 formed concentration gradients from high at the red blood cell end of the platelet-rich fibrin gel (p=1.88×10-5) to low at the plasma end (p=0.19). Insulin-like growth factor-1 concentrations were similar at the red blood cell and plasma ends. The porosities of the platelet-rich fibrin samples taken in sequence from the red blood cell end to the plasma end were 6.5% ± 4.9%, 24.8% ± 7.5%, 30.3% ± 8.5%, 41.4% ± 12.3%, and 40.3% ± 11.7%, respectively, showing a gradual decrease in the compactness of the platelet-rich fibrin network. Cytokine concentrations are positively associated with platelet-rich fibrin microstructure and portion in a rabbit model. As platelet-rich fibrin is the main entity currently used in regenerative medicine, assessing cytokine concentration and the most valuable portion of PRF gels is essential and recommended to all physicians.
-
Three-dimensional structure and cytokine distribution of platelet-rich fibrin
Directory of Open Access Journals (Sweden)
Meng-Yi Bai
Full Text Available OBJECTIVES: Previous reports have revealed that several cytokines (including platelet-derived growth factor-BB, transforming growth factors-β1 and insulin-like growth factor-1 can enhance the rate of bone formation and synthesis of extracellular matrix in orthopaedics or periodontology. This study aimed to determine the concentration of cytokines within platelet-rich fibrin microstructures and investigate whether there are differences in the different portions of platelet-rich fibrin, which has implications for proper clinical use of platelet-rich fibrin gel. METHODS: Whole blood was obtained from six New Zealand rabbits (male, 7 to 39 weeks old, weight 2.7-4 kg; it was then centrifuged for preparation of platelet-rich fibrin gels and harvest of plasma. The resultant platelet-rich fibrin gels were used for cytokine determination, histological analyses and scanning electron microscopy. All plasmas obtained were subject to the same cytokine determination assays for the purpose of comparison. RESULTS: Cytokines platelet-derived growth factor-BB and transforming growth factor-β1 formed concentration gradients from high at the red blood cell end of the platelet-rich fibrin gel (p=1.88×10-5 to low at the plasma end (p=0.19. Insulin-like growth factor-1 concentrations were similar at the red blood cell and plasma ends. The porosities of the platelet-rich fibrin samples taken in sequence from the red blood cell end to the plasma end were 6.5% ± 4.9%, 24.8% ± 7.5%, 30.3% ± 8.5%, 41.4% ± 12.3%, and 40.3% ± 11.7%, respectively, showing a gradual decrease in the compactness of the platelet-rich fibrin network. CONCLUSION: Cytokine concentrations are positively associated with platelet-rich fibrin microstructure and portion in a rabbit model. As platelet-rich fibrin is the main entity currently used in regenerative medicine, assessing cytokine concentration and the most valuable portion of PRF gels is essential and recommended to all physicians.
-
Directory of Open Access Journals (Sweden)
Peng C
2018-04-01
Full Text Available Cheng Peng,1,* Liangyou Gu,1,* Lei Wang,2 Qingbo Huang,1 Baojun Wang,1 Gang Guo,1 Yang Fan,1 Yu Gao,1 Xin Ma,1 Xu Zhang1 1Department of Urology, State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital, Chinese PLA Medical Academy, Beijing, People’s Republic of China; 2Department of Urology, Chinese PLA 534 Hospital, Luoyang, People’s Republic of China *These authors contributed equally to this work Purpose: The clinical benefit of targeted molecular therapy (TMT in renal cell carcinoma (RCC with an inferior vena cava (IVC tumor thrombus remains controversial. The aim of this study was to investigate the effects of presurgical TMT on the heights and levels of IVC thrombi, and to assess its impact on surgical strategy. Patients and methods: We retrospectively reviewed data from 18 patients with RCC involving IVC tumor thrombi who were treated at our hospital with presurgical TMT followed by an IVC thrombectomy. The changes in heights and levels of the IVC thrombi were compared using computed tomography or magnetic resonance imaging. Clinicopathological factors were also evaluated to assess their association with TMT efficacy. Results: The tumor thrombus levels before TMT were stage I in 1 patient (5.6%, II in 12 patients (66.7%, III in 4 patients (22.2%, and IV in 1 patient (5.6%. After a median of two treatment cycles (range: 1–3, the thrombus height decreased measurably in 11 patients (61.1% with an average shrinkage of 17.7%. The thrombus height remained stable in five patients (27.8% and was enlarged in two (11.1%. Downstaging of the thrombus level occurred in four patients (22.2%; the surgical strategy was modified in three patients (16.7% to avoid cardiopulmonary bypass and complicated liver mobilization under robot-assisted laparoscopy. Furthermore, a higher neutrophil count tended to be associated with a worse clinical TMT-associated outcome (P=0.056. Conclusion: Our data suggest a limited influence of presurgical TMT
-
FlnA binding to PACSIN2 F-BAR domain regulates membrane tubulation in megakaryocytes and platelets.
Begonja, Antonija Jurak; Pluthero, Fred G; Suphamungmee, Worawit; Giannini, Silvia; Christensen, Hilary; Leung, Richard; Lo, Richard W; Nakamura, Fumihiko; Lehman, William; Plomann, Markus; Hoffmeister, Karin M; Kahr, Walter H A; Hartwig, John H; Falet, Hervé
2015-07-02
Bin-Amphiphysin-Rvs (BAR) and Fes-CIP4 homology BAR (F-BAR) proteins generate tubular membrane invaginations reminiscent of the megakaryocyte (MK) demarcation membrane system (DMS), which provides membranes necessary for future platelets. The F-BAR protein PACSIN2 is one of the most abundant BAR/F-BAR proteins in platelets and the only one reported to interact with the cytoskeletal and scaffold protein filamin A (FlnA), an essential regulator of platelet formation and function. The FlnA-PACSIN2 interaction was therefore investigated in MKs and platelets. PACSIN2 associated with FlnA in human platelets. The interaction required FlnA immunoglobulin-like repeat 20 and the tip of PACSIN2 F-BAR domain and enhanced PACSIN2 F-BAR domain membrane tubulation in vitro. Most human and wild-type mouse platelets had 1 to 2 distinct PACSIN2 foci associated with cell membrane GPIbα, whereas Flna-null platelets had 0 to 4 or more foci. Endogenous PACSIN2 and transfected enhanced green fluorescent protein-PACSIN2 were concentrated in midstage wild-type mouse MKs in a well-defined invagination of the plasma membrane reminiscent of the initiating DMS and dispersed in the absence of FlnA binding. The DMS appeared less well defined, and platelet territories were not readily visualized in Flna-null MKs. We conclude that the FlnA-PACSIN2 interaction regulates membrane tubulation in MKs and platelets and likely contributes to DMS formation. © 2015 by The American Society of Hematology.
-
International Nuclear Information System (INIS)
Kamal, T.H.; Bahgat, M. M.; Haggag, A. M.; Taha, M. E.
2002-01-01
ONE hundred and twenty male volunteers arranged into 6 equal groups participated in the present study to investigate the influence of age, smoking and season on clot formation, clot lysis and thyroxine hormone. Erythrocyte sedimentation rate, clotting time, platelet count, haemoglobin content, red blood cell count, haematocrit, total leukocytic count, fibrinogen, prothrombin time and concentration, partial thromboplastin time, factor V, VIII, plasminogen and thyroxine hormone were estimated in each group. The effect of age was studied by comparing young individuals (11-16 years) with adult non smokers (30-40 years) . Simultaneously adult non smokers were compared to adult smokers to evaluate the effect of smoking.Three groups: young , adult non smokers and adult smokers during winter were compared with their corresponding groups in summer to assess the season effect.The results revealed that most changes in the three groups were due to temperature variation and the young group had a better thermoregulation control than both adult groups .In non smoker adult group winter caused hypercoagulation with a concomitant increase in fibrinolytic activity as a protective mechanism against thrombus formation. Smoking caused disturbances in many coagulation factors and interaction between smoking and season is evident causing vascular disturbances. In summer smokers are more liable to bleeding, while in winter they are more liable to thrombus formation providing the other condition interfering with bleeding and thrombus formation are constant. There is relative hypothyroidism in smoker group only in summer season
-
Platelet antibodies blood test
This blood test shows if you have antibodies against platelets in your blood. Platelets are a part of the blood ... Chernecky CC, Berger BJ. Platelet antibody - blood. In: Chernecky ... caused by platelet destruction, hypersplenism, or hemodilution. ...
-
Chang, M C; Uang, B J; Tsai, C Y; Wu, H L; Lin, B R; Lee, C S; Chen, Y J; Chang, C H; Tsai, Y L; Kao, C J; Jeng, J H
2007-09-01
Platelet hyperactivity is important in the pathogenesis of cardiovascular diseases. Betel leaf (PBL) is consumed by 200-600 million betel quid chewers in the world. Hydroxychavicol (HC), a betel leaf component, was tested for its antiplatelet effect. We tested the effect of HC on platelet aggregation, thromboxane B(2) (TXB(2)) and reactive oxygen species (ROS) production, cyclooxygenase (COX) activity, ex vivo platelet aggregation and mouse bleeding time and platelet plug formation in vivo. The pharmacokinetics of HC in rats was also assessed. HC inhibited arachidonic acid (AA) and collagen-induced platelet aggregation and TXB(2) production. HC inhibited the thrombin-induced TXB(2) production, but not platelet aggregation. SQ29548, suppressed collagen- and thrombin-induced TXB(2) production, but not thrombin-induced platelet aggregation. HC also suppressed COX-1/COX-2 enzyme activity and the AA-induced ROS production and Ca(2+) mobilization. HC further inhibited the ex vivo platelet aggregation of platelet-rich plasma (>100 nmole/mouse) and prolonged platelet plug formation (>300 nmole/mouse) in mesenteric microvessels, but showed little effect on bleeding time in mouse tail. Moreover, pharmacokinetics analysis found that more than 99% of HC was metabolized within 3 min of administration in Sprague-Dawley rats in vivo. HC is a potent COX-1/COX-2 inhibitor, ROS scavenger and inhibits platelet calcium signaling, TXB(2) production and aggregation. HC could be a potential therapeutic agent for prevention and treatment of atherosclerosis and other cardiovascular diseases through its anti-inflammatory and antiplatelet effects, without effects on haemostatic functions.
-
Selection of donor platelets for alloimmunized patients using a platelet-associated IgG assay
International Nuclear Information System (INIS)
Myers, T.J.; Kim, B.K.; Steiner, M.; Baldini, M.G.
1981-01-01
A quantitative immunofluorescence platelet-associated immunoglobulin-G (PA-IgG) assay was used to detect alloimmunity to platelets in 8/12 multitransfused patients and to perform platelet crossmatching in the 8 alloimmunized patients. The correct separation of multitransfused patients into alloimmune and nonalloimmune groups was substantiated with chromium-51-labeled platelet survival studies. For 5 alloimmunized patients, compatible and incompatible donor platelets were demonstrated by PA-IgG crossmatching and were confirmed by platelet survival studies. With the other 3 alloimmunized patients, only Pa-IgG incompatible donor platelets were found. Survival studies with 5 of these incompatible donor platelets showed markedly reduced survival times on 4 occasions. Pa-IgG compatible donor platelets survived 3.5 to 8.7 days, while Pa-IgG incompatible platelets showed survival times of 0.1 to 2.4 days
-
LENUS (Irish Health Repository)
Kinsella, Ja
2013-04-26
-negative patients (2.8 vs. 2.3%; p=0.0085). DISCUSSION: Recently symptomatic carotid stenosis patients have higher platelet counts (potentially reflecting increased platelet production, mobilisation or reduced clearance) and platelet activation status than asymptomatic patients. MES were more frequently detected in early symptomatic than asymptomatic patients, but the differences between late symptomatic and asymptomatic groups were not significant. Increased lymphocyte-platelet complex formation in recently symptomatic vs. asymptomatic MES-negative patients indicates enhanced platelet activation in this early symptomatic subgroup. Platelet biomarkers, in combination with TCD, have the potential to aid risk-stratification in asymptomatic and symptomatic carotid stenosis patients. This article is protected by copyright. All rights reserved.
-
Comparison of point-of-care methods for preparation of platelet concentrate (platelet-rich plasma).
Weibrich, Gernot; Kleis, Wilfried K G; Streckbein, Philipp; Moergel, Maximilian; Hitzler, Walter E; Hafner, Gerd
2012-01-01
This study analyzed the concentrations of platelets and growth factors in platelet-rich plasma (PRP), which are likely to depend on the method used for its production. The cellular composition and growth factor content of platelet concentrates (platelet-rich plasma) produced by six different procedures were quantitatively analyzed and compared. Platelet and leukocyte counts were determined on an automatic cell counter, and analysis of growth factors was performed using enzyme-linked immunosorbent assay. The principal differences between the analyzed PRP production methods (blood bank method of intermittent flow centrifuge system/platelet apheresis and by the five point-of-care methods) and the resulting platelet concentrates were evaluated with regard to resulting platelet, leukocyte, and growth factor levels. The platelet counts in both whole blood and PRP were generally higher in women than in men; no differences were observed with regard to age. Statistical analysis of platelet-derived growth factor AB (PDGF-AB) and transforming growth factor β1 (TGF-β1) showed no differences with regard to age or gender. Platelet counts and TGF-β1 concentration correlated closely, as did platelet counts and PDGF-AB levels. There were only rare correlations between leukocyte counts and PDGF-AB levels, but comparison of leukocyte counts and PDGF-AB levels demonstrated certain parallel tendencies. TGF-β1 levels derive in substantial part from platelets and emphasize the role of leukocytes, in addition to that of platelets, as a source of growth factors in PRP. All methods of producing PRP showed high variability in platelet counts and growth factor levels. The highest growth factor levels were found in the PRP prepared using the Platelet Concentrate Collection System manufactured by Biomet 3i.
-
Zhang, Shao-Fei; Gao, Chunmei; Lü, Shaoyu; He, Jiujun; Liu, Mingzhu; Wu, Can; Liu, Yijing; Zhang, Xinyu; Liu, Zhen
2017-11-01
Nattokinase (NK) has been used as a new generation thrombolytic drug, due to its high safety, low cost and low side effects. However, it is sensitive to external environment and may lose the enzyme activity easily. Peptide dendrimer possesses functional groups on its surface, adjustable sizes, biodegradability, biocompatibility, and low toxicity, which could be used as ideal carrier for drug protection and delivery. Demonstrated for the first time in this paper, a PEGylated dendrimer (G n -PEG-G n ) composed of polyglutamic acid is designed and synthesized as delivery platform of NK for thrombus treatment. A panel of PEGylated dendrimers with three different generations of 2, 3, 4 was prepared to investigate the effect of dendrimer architecture on the properties and therapeutic efficacy of the resultant NK-loaded delivery systems in terms of the morphology, dimension and enzyme activity. The results demonstrated that the NK-loaded G 3 -PEG-G 3 (G 3 -PEG-G 3 /NK ratio of 6/1), of all the formulations, displayed the optimal enzyme activity for dissolving thrombus in vitro, thus offering great potential for the treatment of thrombus. Copyright © 2017 Elsevier B.V. All rights reserved.
-
Kourtzelis, Ioannis; Kotlabova, Klara; Lim, Jong-Hyung; Mitroulis, Ioannis; Ferreira, Anaisa; Chen, Lan-Sun; Gercken, Bettina; Steffen, Anja; Kemter, Elisabeth; Klotzsche-von Ameln, Anne; Waskow, Claudia; Hosur, Kavita; Chatzigeorgiou, Antonios; Ludwig, Barbara; Wolf, Eckhard; Hajishengallis, George; Chavakis, Triantafyllos
2016-04-01
Platelet-monocyte interactions are strongly implicated in thrombo-inflammatory injury by actively contributing to intravascular inflammation, leukocyte recruitment to inflamed sites, and the amplification of the procoagulant response. Instant blood-mediated inflammatory reaction (IBMIR) represents thrombo-inflammatory injury elicited upon pancreatic islet transplantation (islet-Tx), thereby dramatically affecting transplant survival and function. Developmental endothelial locus-1 (Del-1) is a functionally versatile endothelial cell-derived homeostatic factor with anti-inflammatory properties, but its potential role in IBMIR has not been previously addressed. Here, we establish Del-1 as a novel inhibitor of IBMIR using a whole blood-islet model and a syngeneic murine transplantation model. Indeed, Del-1 pre-treatment of blood before addition of islets diminished coagulation activation and islet damage as assessed by C-peptide release. Consistently, intraportal islet-Tx in transgenic mice with endothelial cell-specific overexpression of Del-1 resulted in a marked decrease of monocytes and platelet-monocyte aggregates in the transplanted tissues, relative to those in wild-type recipients. Mechanistically, Del-1 decreased platelet-monocyte aggregate formation, by specifically blocking the interaction between monocyte Mac-1-integrin and platelet GPIb. Our findings reveal a hitherto unknown role of Del-1 in the regulation of platelet-monocyte interplay and the subsequent heterotypic aggregate formation in the context of IBMIR. Therefore, Del-1 may represent a novel approach to prevent or mitigate the adverse reactions mediated through thrombo-inflammatory pathways in islet-Tx and perhaps other inflammatory disorders involving platelet-leukocyte aggregate formation.
-
Apheresis platelet concentrates contain platelet-derived and endothelial cell-derived microparticles
Rank, A.; Nieuwland, R.; Liebhardt, S.; Iberer, M.; Grützner, S.; Toth, B.; Pihusch, R.
2011-01-01
Background and Objectives Microparticles (MP) are membrane vesicles with thrombogenic and immunomodulatory properties. We determined MP subgroups from resting platelets, activated platelets and endothelial cells in donors and apheresis platelet concentrates (PC). Material and Methods MP were double
-
Platelet Counts in Insoluble Platelet-Rich Fibrin Clots: A Direct Method for Accurate Determination
Directory of Open Access Journals (Sweden)
Yutaka Kitamura
2018-02-01
Full Text Available Platelet-rich fibrin (PRF clots have been used in regenerative dentistry most often, with the assumption that growth factor levels are concentrated in proportion to the platelet concentration. Platelet counts in PRF are generally determined indirectly by platelet counting in other liquid fractions. This study shows a method for direct estimation of platelet counts in PRF. To validate this method by determination of the recovery rate, whole-blood samples were obtained with an anticoagulant from healthy donors, and platelet-rich plasma (PRP fractions were clotted with CaCl2 by centrifugation and digested with tissue-plasminogen activator. Platelet counts were estimated before clotting and after digestion using an automatic hemocytometer. The method was then tested on PRF clots. The quality of platelets was examined by scanning electron microscopy and flow cytometry. In PRP-derived fibrin matrices, the recovery rate of platelets and white blood cells was 91.6 and 74.6%, respectively, after 24 h of digestion. In PRF clots associated with small and large red thrombi, platelet counts were 92.6 and 67.2% of the respective total platelet counts. These findings suggest that our direct method is sufficient for estimating the number of platelets trapped in an insoluble fibrin matrix and for determining that platelets are distributed in PRF clots and red thrombi roughly in proportion to their individual volumes. Therefore, we propose this direct digestion method for more accurate estimation of platelet counts in most types of platelet-enriched fibrin matrix.
-
Directory of Open Access Journals (Sweden)
Amit Agarwal
2014-11-01
Full Text Available We aimed at comparing the sensitivity of magnetic resonance (MR susceptibility-weighted imaging (SWI with computed tomography angiography (CTA in the detection of middle cerebral artery (MCA thrombus in acute stroke. Seventy-nine patients with acute MCA stroke was selected using our search engine software; only the ones showing restricted diffusion in the MCA territory on diffusion-weighted images were included. We finally selected 35 patients who had done both MRI (including SWI and CTA. Twenty random subjects with completely normal MRI (including SWI exam were selected as control. Two neuroradiologists (blinded to the presence or absence of stroke reviewed the SW images and then compared the findings with CT angiogram (in patients with stroke. The number of MCA segments showing thrombus in each patient was tabulated to estimate the thrombus burden. Thrombus was detected on SWI in one or more MCA segments in 30 out of 35 patients, on the first review. Of the 30, SWI showed thrombus in more than one MCA segments in 7 patients. CTA depicted branch occlusion in 31 cases. Thrombus was seen on both SWI and CTA in 28 patients. Thrombus was noted in two patients on SWI only, with no corresponding abnormality seen on CTA. Two patients with acute MCA showed no vascular occlusion or thrombus on either CTA or SWI. Only two case of false-positive thrombus was reported in normal control subjects. Susceptibility-weighted images had sensitivity and specificity of 86% and 90% respectively, with positive predictive value 94%. Sensitivity was 86% for SWI, compared with 89% for CTA, and this difference was statistically insignificant (P>0.05. Of all the positive cases on CTA (31 corresponding thrombus was seen on SWI in 90% of subjects (28 of 31. Susceptibility-weighted imaging has high sensitivity for detection of thrombus in acute MCA stroke. Moreover, SWI is a powerful technique for estimation of thrombus burden, which can be challenging on CTA.
-
Reference intervals for platelet aggregation assessed by multiple electrode platelet aggregometry
DEFF Research Database (Denmark)
Rubak, Peter; Villadsen, Kirsten; Hvas, Anne-Mette
2012-01-01
Abstract Introduction Analyses of platelet aggregation in hirudin whole blood using Multiplate® was validated. Reference intervals for the most commonly used agonists were established, and the association between platelet aggregation, age, gender and haematological values was analysed. Material...... and methods We included 121 healthy individuals to establish reference intervals and six healthy individuals for evaluation of the day-to-day variation. Platelet aggregation was evaluated on hirudin whole blood employing Multiplate® induced by arachidonic acid, ADP, collagen and ristocetin (RISTOlow...... after adjusting for age and gender except for RISTOhigh. A positive significant association was found between platelet count and platelet aggregation (p
-
Evaluation of platelet aggregation in platelet concentrates: storage implications
Directory of Open Access Journals (Sweden)
Neiva Teresinha J.C.
2003-01-01
Full Text Available The use of hemo-derivatives is nowadays a fundamentally important therapeutic modality in the exercise of medicine. Among the various hemo-components employed, we have the platelet concentrate (PC, indicated in cases of hemorrhagic disturbances. We previously showed that platelet function in blood donors is reduced in their screening phase and after the separation process of PCs. Currently, we are providing evidence for the existence of biochemical and functional changes in PC preparations stored for three days at temperatures of 20 ± 2 ºC. Platelet concentrates from 40 healthy donors, collected in CPD anticoagulant and PL-146 polyvinylchloride containers, were examined in order to determine the pH value, pCO2 ,pO2 and lactate concentrations. In addition, the aggregation of platelets with thrombin and collagen were examined to evaluate platelet function. A pH increase from 7.07 ± 0.04 to 7.36 ± 0.07 (p < 0.01 was observed. The pCO2 concentration decreased progressively from 69.2 ± 7.7 mmHg to 28.8 ± 6.2 mmHg (p < 0.001 during the storage period. In contrast, pO2 value increase from 103.4 ± 30.6 to 152.3 ± 24.6 mmHg (p < 0.001 was evidenced during the 48 hours of storage. The lactate concentration increased from 17.97 ± 5.2 to 57.21 ± 5.7 mg/dl (p < 0.001. Platelet aggregation using 0.25 U/ml-thrombin and 2.0 µg/ml-collagen showed significant hypofunction from 61.8 ± 2.7% to 24.8 ± 9.8% and 62.7±5.0 to 33.4± 6.2 (p < 0.001, respectively. We concluded that the evaluated biochemical parameters and the platelet function changed significantly when the platelets were kept under routine storage conditions.
-
López-Linares, Karen; Aranjuelo, Nerea; Kabongo, Luis; Maclair, Gregory; Lete, Nerea; Ceresa, Mario; García-Familiar, Ainhoa; Macía, Iván; González Ballester, Miguel A
2018-05-01
Computerized Tomography Angiography (CTA) based follow-up of Abdominal Aortic Aneurysms (AAA) treated with Endovascular Aneurysm Repair (EVAR) is essential to evaluate the progress of the patient and detect complications. In this context, accurate quantification of post-operative thrombus volume is required. However, a proper evaluation is hindered by the lack of automatic, robust and reproducible thrombus segmentation algorithms. We propose a new fully automatic approach based on Deep Convolutional Neural Networks (DCNN) for robust and reproducible thrombus region of interest detection and subsequent fine thrombus segmentation. The DetecNet detection network is adapted to perform region of interest extraction from a complete CTA and a new segmentation network architecture, based on Fully Convolutional Networks and a Holistically-Nested Edge Detection Network, is presented. These networks are trained, validated and tested in 13 post-operative CTA volumes of different patients using a 4-fold cross-validation approach to provide more robustness to the results. Our pipeline achieves a Dice score of more than 82% for post-operative thrombus segmentation and provides a mean relative volume difference between ground truth and automatic segmentation that lays within the experienced human observer variance without the need of human intervention in most common cases. Copyright © 2018 Elsevier B.V. All rights reserved.
-
Binsker, Ulrike; Palankar, Raghavendra; Wesche, Jan; Kohler, Thomas P; Prucha, Josephine; Burchhardt, Gerhard; Rohde, Manfred; Schmidt, Frank; Bröker, Barbara M; Mamat, Uwe; Pané-Farré, Jan; Graf, Anica; Ebner, Patrick; Greinacher, Andreas; Hammerschmidt, Sven
2018-04-01
Staphylococcus aureus can cause bloodstream infections associated with infective endocarditis (IE) and disseminated intravascular coagulopathy (DIC). Both complications involve platelets. In view of an increasing number of antibiotic-resistant strains, new approaches to control systemic S. aureus infection are gaining importance. Using a repertoire of 52 recombinant S. aureus proteins in flow cytometry-based platelet activation and aggregation assays, we identified, in addition to the extracellular adherence protein Eap, three secreted staphylococcal proteins as novel platelet activating proteins. Eap and the chemotaxis inhibitory protein of S. aureus (CHIPS), the formyl peptide receptor-like 1 inhibitory protein (FLIPr) and the major autolysin Atl induced P-selectin expression in washed platelets and platelet-rich plasma. Similarly, AtlA, CHIPS and Eap induced platelet aggregation in whole blood. Fluorescence microscopy illustrated that P-selectin expression is associated with calcium mobilization and re-organization of the platelet actin cytoskeleton. Characterization of the functionally active domains of the major autolysin AtlA and Eap indicates that the amidase domain of Atl and the tandem repeats 3 and 4 of Eap are crucial for platelet activation. These results provide new insights in S. aureus protein interactions with platelets and identify secreted proteins as potential treatment targets in case of antibiotic-resistant S. aureus infection. Schattauer GmbH Stuttgart.
-
Crowther, M; Ford, I; Jeffrey, R R; Urbaniak, S J; Greaves, M
2000-10-01
Platelet dysfunction has a major contribution in bleeding after cardiopulmonary bypass (CPB) and transfusion of platelets is frequently used to secure haemostasis. Allogeneic platelets prepared for transfusion are functionally impaired. Autologous platelets harvested preoperatively require a shorter storage time before transfusion and their use also avoids the risks associated with transfusion of allogeneic blood products. For the first time, we have compared the functional quality of autologous platelets with allogeneic platelets prepared by two methods, immediately before infusion. Platelet activation was assessed by P-selectin expression and fibrinogen binding using flow cytometry. We also monitored the effects of CPB surgery and re-infusion of autologous platelets on platelet function. Autologous platelet-rich plasma (PRP) contained a significantly lower (P platelets compared with allogeneic platelet preparations, and also contained a significantly higher (P platelets. Allogeneic platelets prepared by donor apheresis were more activated and less responsive than those produced by centrifugation of whole blood. In patients' blood, the percentage of platelets expressing P-selectin or binding fibrinogen increased significantly after CPB (P platelets responsive to in vitro agonists was decreased (P platelet activation during the procedure. The percentage of activated platelets decreased (statistically not significant) after re-infusion of autologous PRP. P-selectin expression had returned to pre-CPB levels 24 h post-operatively. Autologous platelet preparations display minimal activation, but remain responsive. Conservation of platelet function may contribute to the potential clinical benefits of autologous transfusion in cardiopulmonary bypass.
-
Directory of Open Access Journals (Sweden)
Marcinkiewicz C
2017-05-01
Full Text Available Cezary Marcinkiewicz,1,2 Jonathan A Gerstenhaber,1 Mark Sternberg,2 Peter I Lelkes,1 Giora Feuerstein1,2 1Department of Bioengineering, College of Engineering, Temple University, Philadelphia, 2Debina Diagnostic, Inc., Newton Square, PA, USA Abstract: Thromboembolic events (TEE underwrite key causes of death in developed countries. While advanced imaging technologies such as computed tomography scans serve to diagnose blood clots during acute cardiovascular events, no such technology is available in routine primary care for TEE risk assessment. Here, we describe an imaging platform technology based on bioengineered fluorescent nanodiamond particles (F-NDPs functionalized with bitistatin (Bit, a disintegrin that specifically binds to the αIIbβ3 integrin, platelet fibrinogen receptor (PFR on activated platelets. Covalent linkage of purified Bit to F-NDP was concentration-dependent and saturable, as validated by enzyme-linked immunosorbent assay using specific anti-Bit antibodies. F-NDP–Bit interacted with purified PFR, either in immobilized or soluble form. Lotrafiban, a nonpeptide, αIIbβ3 receptor antagonist, specifically blocked F-NDP–Bit–PFR complex formation. Moreover, F-NDP–Bit specifically binds to activated platelets incorporated into a clot generated by thrombin-activated rat platelet-rich plasma (PRP. Our results suggest that engineered F-NDP–Bit particles could serve as noninvasive, “real-time” optical diagnostics for clots present in blood vessels. Keywords: carbon nanoparticles, blood clots, imaging, platelet fibrinogen receptor, fluorescence, disintegrin, thromboembolic complications, thrombosis
-
2014-06-12
through a series of centrifugation steps: 200 g for 10 min with minimal braking separated platelet rich plasma (PRP) which was collected and stored at...localization of fVa and phospholipid as a result of platelet deposition accelerates thrombin generation and fibrin formation/crosslinking at sites of...is ineffective at inhibiting both platelet adhesion and fibrin formation in blood flow models except at extreme Figure 7. aPC concentrations below 10
-
Anomalous columnar order of charged colloidal platelets
Morales-Anda, L.; Wensink, H. H.; Galindo, A.; Gil-Villegas, A.
2012-01-01
Monte Carlo computer simulations are carried out for a model system of like-charged colloidal platelets in the isothermal-isobaric ensemble (NpT). The aim is to elucidate the role of electrostatic interactions on the structure of synthetic clay systems at high particle densities. Short-range repulsions between particles are described by a suitable hard-core model representing a discotic particle. This potential is supplemented with an electrostatic potential based on a Yukawa model for the screened Coulombic potential between infinitely thin disklike macro-ions. The particle aspect-ratio and electrostatic parameters were chosen to mimic an aqueous dispersion of thin, like-charged, rigid colloidal platelets at finite salt concentration. An examination of the fluid phase diagram reveals a marked shift in the isotropic-nematic transition compared to the hard cut-sphere reference system. Several statistical functions, such as the pair correlation function for the center-of-mass coordinates and structure factor, are obtained to characterize the structural organization of the platelets phases. At low salinity and high osmotic pressure we observe anomalous hexagonal columnar structures characterized by interpenetrating columns with a typical intercolumnar distance corresponding to about half of that of a regular columnar phase. Increasing the ionic strength leads to the formation of glassy, disordered structures consisting of compact clusters of platelets stacked into finite-sized columns. These so-called "nematic columnar" structures have been recently observed in systems of charge-stabilized gibbsite platelets. Our findings are corroborated by an analysis of the static structure factor from a simple density functional theory.
-
Rank, A; Nieuwland, R; Liebhardt, S; Iberer, M; Grützner, S; Toth, B; Pihusch, R
2011-02-01
Microparticles (MP) are membrane vesicles with thrombogenic and immunomodulatory properties. We determined MP subgroups from resting platelets, activated platelets and endothelial cells in donors and apheresis platelet concentrates (PC). MP were double stained with annexin V and CD61 (platelet-derived MP; PMP), P-selectin or CD63 (MP from activated platelets) and CD144 plus E-selectin (endothelial cell-derived MP; EMP) and detected by flow cytometry in platelet donors (n=36) and apheresis PC (n=11; Trima™). PC contained MP, mainly from resting platelets [93% (90-95)], and minor fractions of PMP from activated platelets [P-selectin(+) or CD63(+); 4·8% (3·2-7·7) and 2·6% (2·0-4·0)]. Compared to donors, levels of annexin V+ MP, PMP, P-selectin(+) and CD63(+) MP were 1·7-, 2·3-, 8·6- and 3·1-fold higher in PC (all P<0·05). During storage (1-5 days), levels of annexin V+ MP and PMP did not increase, although small increases in the fraction of P-selectin(+) or CD63(+) MP occurred (both P<0·05). PC also contained EMP, which were 2·6- to 3·7-fold enriched in PC compared to donors (P<0·05). Transfusion of apheresis PC also results in transfusion of HLA-carrying PMP and EMP. This might counteract the aim of reducing transfused HLA load by leucodepletion. The increases in PMP exposing P-selectin or CD63 reflect mild platelet activation during storage. We conclude that in leucodepleted platelet apheresis using fluidized particle bed technology, MP are harvested mainly from the donor by apheresis. Improvement in apheresis technology might reduce MP load. © 2010 The Author(s). Vox Sanguinis © 2010 International Society of Blood Transfusion.
-
Morel, Agnieszka; Rywaniak, Joanna; Bijak, Michał; Miller, Elżbieta; Niwald, Marta; Saluk, Joanna
2017-06-01
The epidemiological studies confirm an increased risk of cardiovascular disease in multiple sclerosis, especially prothrombotic events directly associated with abnormal platelet activity. The aim of our study was to investigate the level of blood platelet activation in the circulation of patients with chronic phase of multiple sclerosis (SP MS) and their reactivity in response to typical platelets' physiological agonists. We examined 85 SP MS patients diagnosed according to the revised McDonald's criteria and 50 healthy volunteers as a control group. The platelet activation and reactivity were assessed using flow cytometry analysis of the following: P-selectin expression (CD62P), activation of GP IIb/IIIa complex (PAC-1 binding), and formation of platelet microparticles (PMPs) and platelet aggregates (PA) in agonist-stimulated (ADP, collagen) and unstimulated whole blood samples. Furthermore, we measured the level of soluble P-selectin (sP-selectin) in plasma using ELISA method, to evaluate the in vivo level of platelet activation, both in healthy and SP MS subjects. We found a statistically significant increase in P-selectin expression, GP IIb/IIIa activation, and formation of PMPs and PA, as well as in unstimulated and agonist-stimulated (ADP, collagen) platelets in whole blood samples from patients with SP MS in comparison to the control group. We also determined the higher sP-selectin level in plasma of SP MS subjects than in the control group. Based on the obtained results, we might conclude that during the course of SP MS platelets are chronically activated and display hyperreactivity to physiological agonists, such as ADP or collagen.
-
Directory of Open Access Journals (Sweden)
A Suchetha
2015-01-01
Full Text Available Context: Platelet-rich-plasma (PRP and Platelet-rich-fibrin (PRF are extensively used autologous platelet concentrates in periodontal regeneration, and PRF has a better efficacy as compared to PRP. The rationale for this difference has often been attributed to the difference in the structure of the fibrin matrix. However, the effect of concentration of platelets on the regenerative potential of these concentrates is obscure. Aims: The study was conducted to evaluate and compare, clinically and radiographically, the efficacy of PRF and PRP in the treatment of periodontal endosseous defects and to assess the effect of platelet concentration on periodontal regeneration. Materials and Methods: Twenty intrabony defects were selected and divided into two groups randomly by the coin toss method. Group I received PRP and Group II subjects were treated with PRF. The platelet counts in PRP and PRF were analyzed. Clinical and radiological parameters were assessed at baseline and 3, 6, and 9 months postoperatively. Statistical Analysis: Kruskal–Wallis Chi-square test, Wilcoxon signed rank test, t-test, and Spearman's rank correlation were used for statistical analysis of data. Results: There was statistically significant improvement in all the parameters in the two groups except in relation to gingival recession. There was a statistically significant difference between the platelet count in Group I and Group II (P = 0.002. Conclusion: PRP and PRF appear to have nearly comparable effects in terms of periodontal regeneration. The concentration of platelets appears to play a paradoxical role in regeneration. The regenerative potential of platelets appears to be optimal within a limited range.
-
Jo, Chris H; Roh, Young Hak; Kim, Ji Eun; Shin, Sue; Yoon, Kang Sup
2013-10-01
Despite the increasing clinical use of topical platelet-rich plasma (PRP) to enhance tissue healing and regeneration, there is no properly standardized method of autologous PRP gel preparation. This study examined the effect of the centrifugation time and gravitational force (g) on the platelet recovery ratio of PRP and determined the most effective centrifugation conditions for preparing PRP. Two-step centrifugations for preparing PRP were used in 39 subjects who had consented prior to the study's start. The separating centrifugation (Step 1, used to separate whole blood into its two main components: red blood cells and plasma) was tested from 500g to 1900g at 200g increments for 5 minutes (min), and from 100g to 1300g at 200g increments for 10 minutes. After separating centrifugation, upper plasma layer was transferred to another plain tube for the condensation centrifugation and remaining lower cell layer was discarded. The condensation centrifugation (Step 2, used to condense the platelets in the separated plasma) was tested at 1000g for 15 min, 1500g for 15 min, 2000g for 5 min and 3000g for 5 min, additionally at 1000g for 10 min and 1500g for 10 min. Platelet gelation was induced by adding 10% calcium gluconate to final PRP with volume ratio of 1:10. The optimal separating centrifugation conditions were followed by 900g for 5 minutes and the condensation conditions were followed by 1500g for 15 minutes, of which recovery ratios were 92.0 ± 3.1% and 84.3 ± 10.0%, respectively.
-
El Haouari, Mohammed
2017-10-05
Enhanced platelet activation and thrombosis are linked to various cardiovascular diseases. Among other mechanisms, oxidative stress seems to play a pivotal role in platelet hyperactivity. Indeed, upon stimulation by physiological agonists, human platelets generate and release several types of reactive oxygen species (ROS) such as O2-, H2O2 or OH- , further amplifying the platelet activation response via various signalling pathways, including, formation of isoprostanes, Ca2+ mobilization and NO inactivation. Furthermore, excessive platelet ROS generation, incorporation of free radicals from environment and/or depletion of antioxidants induce pro-oxidant, pro-inflammatory and platelet hyperaggregability effects, leading to the incidence of cardiovascular events. Here, we review the current knowledge regarding the effect of oxidative stress on platelet signaling pathways and its implication in CVD such as type 2 diabetes mellitus. We also summarize the role of natural antioxidants included in vegetables, fruits and medicinal herbs in reducing platelet function via an oxidative stress-mediated mechanism. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
-
Directory of Open Access Journals (Sweden)
Katie L Lannan
2015-02-01
Full Text Available Platelets are small anucleate blood cells derived from megakaryocytes. In addition to their pivotal roles in hemostasis, platelets are the smallest, yet most abundant, immune cell and regulate inflammation, immunity, and disease progression. Although platelets lack DNA, and thus no functional transcriptional activities, they are nonetheless rich sources of RNAs, possess an intact spliceosome, and are thus capable of synthesizing proteins. Previously, it was thought that platelet RNAs and translational machinery were remnants from the megakaryocyte. We now know that the initial description of platelets as cellular fragments is an antiquated notion, as mounting evidence suggests otherwise. Therefore, it is reasonable to hypothesize that platelet transcription factors are not vestigial remnants from megakaryoctes, but have important, if only partly understood functions. Proteins play multiple cellular roles to minimize energy expenditure for maximum cellular function; thus, the same can be expected for transcription factors. In fact, numerous transcription factors have non-genomic roles, both in platelets and in nucleated cells. Our lab and others have discovered the presence and nongenomic roles of transcription factors in platelets, such as the nuclear factor kappa β (NFκB family of proteins and peroxisome proliferator activated receptor gamma (PPARγ. In addition to numerous roles in regulating platelet activation, functional transcription factors can be transferred to vascular and immune cells through platelet microparticles. This method of transcellular delivery of key immune molecules may be a vital mechanism by which platelet transcription factors regulate inflammation and immunity. At the very least, platelets are an ideal model cell to dissect out the nongenomic roles of transcription factors in nucleated cells. There is abundant evidence to suggest that transcription factors in platelets play key roles in regulating inflammatory and
-
Platelet aggregation and quality control of platelet concentrates produced in the Amazon Blood Bank
Directory of Open Access Journals (Sweden)
Maria José Dantas Coêlho
2011-01-01
Full Text Available BACKGROUND: The study of platelet aggregation is essential to assess in vitro platelet function by different platelet activation pathways. OBJECTIVE: To assess aggregation and biochemical parameters of random platelet concentrates produced at the Fundação HEMOAM using the quality control tests defined by law. METHODS: Whole blood samples from 80 donors and the respective platelet concentrate units were tested. Platelet concentrates were tested (platelet count, aggregation and pH on days 1, 3 and 5 of storage. Additionally a leukocyte count was done only on day 1 and microbiological tests on day 5 of storage. Collagen and adenosine diphosphate were used as inducing agonists for platelet aggregation testing. RESULTS: Donor whole blood had normal aggregation (aggregation with adenosine diphosphate = 67% and with collagen = 78%. The median aggregation in platelet concentrates with adenosine diphosphate was low throughout storage (18% on day 1, 7% on day 3 and 6% on day 5 and the median aggregation with collagen was normal only on day 1 and low thereafter (54.4% on day 1, 20.5% on day 3 and 9% on day 5. CONCLUSION: Although the results were within the norms required by law, platelet concentrates had low aggregation rates. We suggest the inclusion of a functional assessment test for the quality control of platelet concentrates for a more effective response to platelet replacement therapy.
-
EXTENDED STORAGE OF BUFFY-COAT PLATELET CONCENTRATES IN PLASMA OR A PLATELET ADDITIVE SOLUTION
Slichter, Sherrill J.; Bolgiano, Doug; Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Bailey, S. Lawrence; Pellham, Esther
2014-01-01
Background Platelet concentrates prepared from whole blood in the U.S. are made using the platelet-rich-plasma (PRP) method. The platelet concentrates must be made within 8 hours of blood collection and stored for only 5 days. In Europe and Canada, platelet concentrates are made using the buffy-coat (BC) method from whole blood held overnight at 22°C and storage times may be up to 7 days. Our studies were designed to determine how long BC platelets can be stored in plasma or Plasmalyte while meeting the FDA’s post-storage viability criteria. Study Design, Materials, And Methods Normal subjects donated whole blood that was stored at 22°C for 22 ± 2 hours prior to preparation of BC platelets. Platelets were stored for 5 to 8 days in either plasma or Plasmalyte concentrations of 65% or 80%. Radiolabeled autologous stored versus fresh platelet recoveries and survivals were assessed as well as post-storage in vitro assays. Results BC platelets stored in either plasma or 65% Plasmalyte met FDA post-storage platelet recovery criteria for 7 days but survivals for only 6 days, while storage in 80% Plasmalyte gave very poor results. Both stored platelet recoveries and survivals correlated with the same donor’s fresh results, but the correlation was much stronger between recoveries than survivals. In vitro measures of extent of shape change, morphology score, and pH best predicted post-storage platelet recoveries, while annexin V binding best predicted platelet survivals. Conclusion BC platelets stored in either plasma or 65% Plasmalyte meet FDA’s post-storage viability criteria for 6 days. PMID:24673482
-
In situ formation of CA6 platelets in Al2O3 and Al2O3/ZrO2 matrices
Belmonte , M.; SÁnchez-Herencia , A.; Moreno , R.; Miranzo , P.; Moya , J.; Tomsia , A.
1993-01-01
Al2O3 and Al2O3/ZrO2 compacts containing CaO as a dopant have been sintered under different conditions and atmospheres: air, high vacuum (> 10-6torr). SEM observations have been made on the polished surfaces of sintered and also of annealed samples. Only after the annealing treatment in air at temperatures ranging from 1400° to 1 500°C, a massive formation of CA6 platelets was detected in samples sintered in low oxygen partial pressure atmospheres.ln order to clarify the mechanism of formatio...
-
International Nuclear Information System (INIS)
Stratton, J.R.; Ballem, P.J.; Gernsheimer, T.; Cerqueira, M.; Slichter, S.J.
1989-01-01
Using autologous 111 In-labeled platelets, platelet kinetics and the sites of platelet destruction were assessed in 16 normal subjects (13 with and three without spleens), in 17 studies of patients with primary autoimmune thrombocytopenic purpura (AITP), in six studies of patients with secondary AITP, in ten studies of patients with AITP following splenectomy, and in five thrombocytopenic patients with myelodysplastic syndromes. In normal subjects, the spleen accounted for 24 +/- 4% of platelet destruction and the liver for 15 +/- 2%. Untreated patients with primary AITP had increased splenic destruction (40 +/- 14%, p less than 0.001) but not hepatic destruction (13 +/- 5%). Compared with untreated patients, prednisone treated patients did not have significantly different spleen and liver platelet sequestration. Patients with secondary AITP had similar platelet counts, platelet survivals, and increases in splenic destruction of platelets as did patients with primary AITP. In contrast, patients with myelodysplastic syndromes had a normal pattern of platelet destruction. In AITP patients following splenectomy, the five nonresponders all had a marked increase (greater than 45%) in liver destruction compared to five responders (all less than 40%). Among all patients with primary or secondary AITP, there was an inverse relationship between the percent of platelets destroyed in the liver plus spleen and both the platelet count (r = 0.75, p less than 0.001) and the platelet survival (r = 0.86, p less than 0.001). In a stepwise multiple linear regression analysis, total liver plus spleen platelet destruction, the platelet survival and the platelet turnover were all significant independent predictors of the platelet count. Thus platelet destruction is shifted to the spleen in primary and secondary AITP. Failure of splenectomy is associated with a marked elevation in liver destruction
-
Directory of Open Access Journals (Sweden)
Tawatchai Taweemonkongsap
2008-04-01
CONCLUSION: These results support the aggressive surgical removal of RCC with IVC thrombus as the initial treatment. Most of the thrombi can be approached and safely controlled by a transabdominal approach without any form of bypass. Tumour thrombus removal provides a high survival chance and offers improvement in quality of life.
-
Boyer, Nathan; Gupta, Rajesh; Schevchuck, Alex; Hindnavis, Vindhya; Maliske, Seth; Sheldon, Mark; Drachman, Douglas; Yeghiazarians, Yerem
2014-06-01
Coronary artery aneurysm (CAA) is an uncommon clinical finding, with an incidence varying from 1.5%-4.9% in adults, and is usually considered a variant of coronary artery disease (CAD). CAA identified in the context of acute coronary syndrome (ACS) represents a unique management challenge, particularly if the morphology of the CAA is suspected to have provoked the acute clinical syndrome. CAA is associated with thrombus formation due to abnormal laminar flow, as well as abnormal platelet and endothelial-derived pathophysiologic factors within the CAA. Once formed, mural thrombus may potentiate the deposition of additional thrombus within aneurysmal segments. Percutaneous revascularization of CAA has been associated with complications including distal embolization of thrombus, no-reflow phenomenon, stent malapposition, dissection, and rupture. Presently, there are no formal guidelines to direct the management of CAA in patients presenting with ACS; controversies exist whether conservative, surgical, or catheter-based management should be pursued. In this manuscript, we present an extensive review of the existing literature and associated clinical guidelines, and propose a management algorithm for patients with this complex clinical scenario. Armed with this perspective, therapeutic decisions may be tailored to synthesize patient factors and preferences, individualized clinical assessment, and existing American Heart Association/American College of Cardiology guidelines for management of ACS.
-
In vitro function of random donor platelets stored for 7 days in composol platelet additive solution
Directory of Open Access Journals (Sweden)
Gupta Ashish
2011-01-01
Full Text Available Background and Aim: Platelets are routinely isolated from whole blood and stored in plasma for 5 days. The present study was done to assess the in vitro function of random donor platelets stored for 7 days in composol platelet additive solution at 22°C. Materials and Methods: The study sample included 30 blood donors of both sex in State Blood Bank, CSM Medical University, Lucknow. Random donor platelets were prepared by platelet rich plasma method. Whole blood (350 ml was collected in anticoagulant Citrate Phosphate Dextrose Adenine triple blood bags. Random donor platelets were stored for 7 days at 22°C in platelet incubators and agitators, with and without additive solution. Results: Platelet swirling was present in all the units at 22°C on day 7, with no evidence of bacterial contamination. Comparison of the mean values of platelet count, platelet factor 3, lactate dehydrogenase, pH, glucose and platelet aggregation showed no significant difference in additive solution, whereas platelet factor 3, glucose and platelet aggregation showed significant difference (P < 0.001 on day 7 without additive solution at 22°C. Conclusion: Our study infers that platelet viability and aggregation were best maintained within normal levels on day 7 of storage in platelet additive solution at 22°C. Thus, we may conclude that in vitro storage of random donor platelets with an extended shelf life of 7 days using platelet additive solution may be advocated to improve the inventory of platelets.
-
In vitro function of random donor platelets stored for 7 days in composol platelet additive solution
Directory of Open Access Journals (Sweden)
Gupta Ashish
2011-01-01
Full Text Available Background and Aim: Platelets are routinely isolated from whole blood and stored in plasma for 5 days. This study was done to assess the in vitro function of random donor platelets stored for 7 days in composol platelet additive solution at 22°C. Materials and Methods: The study sample included 30 blood donors of both sex in State Blood Bank, C S M Medical University, Lucknow. Random donor platelets were prepared by the platelet-rich plasma method. Whole blood (350 ml was collected in anticoagulant Citrate Phosphate Dextrose Adenine triple blood bags. Random donor platelets were stored for 7 days at 22°C in platelet incubators and agitators with and without additive solution. Results: Platelet swirling was present in all the units at 22°C on day 7 with no evidence of bacterial contamination. Comparison of the mean values of platelet count, platelet factor 3, lactate dehydrogenase, pH, glucose and platelet aggregation showed no significant difference in additive solution while platelet factor 3, glucose and platelet aggregation showed significant difference (P < 0.001 on day 7 without additive solution at 22°C. Conclusion: Our study infers that the platelet viability and aggregation were the best maintained within normal levels on day 7 of storage in platelet additive solution at 22°C. Thus, we may conclude that in vitro storage of random donor platelets with an extended shelf life of 7 days using platelet additive solution may be advocated to improve the inventory of platelets.
-
McBride, J. A.
1968-01-01
Platelet adhesiveness has been measured in citrated whole blood and in platelet-rich plasma obtained from normal subjects, splenectomized patients, and from patients in whom the diagnosis of recurrent venous thrombosis had been made. The duration of centrifugation used in the preparation of platelet-rich plasma was found to have a profound effect on the measurement of platelet adhesiveness because the figure for platelet adhesiveness measured in platelet-rich plasma obtained by centrifugation was considerably lower than that found in citrated whole blood. This effect was particularly marked when platelet-rich plasma was obtained from subjects in whom platelet adhesiveness measured in whole blood was increased. PMID:5699080
-
A Novel Platelet Concentrate: Titanium-Prepared Platelet-Rich Fibrin
Mustafa Tunalı; Hakan Özdemir; Zafer Küçükodacı; Serhan Akman; Emre Yaprak; Hülya Toker; Erhan Fıratlı
2014-01-01
We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF). The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun's leukocyte- and platelet-rich fibrin (L-PRF) method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn us...
-
An experimental study on MR imaging of jugular venous thrombosis in dogs
International Nuclear Information System (INIS)
Lee, Joo Hyuk; Choi, Sin Eun; Park, Jae Hyung; Kim, Jae Seung; Lee, Sun Gyu; Chang, Kee Hyun
1993-01-01
This study was designed to evaluate the potential application of MRI in differentiating static blood from thrombus, age-related changes of thrombus and the signal differences of the intravascular thrombus in various pulse sequences. External jugular vein was ligated at both upper and lower ends to from a static blood column, and thrombin was injected into the column to cause venous thrombosis in a total of 15 mongrel dogs. The MR images were obtained with T1- and T2-weighted spin echo and gradient echo techniques, lmmediately after the formation of static blood and after 2 hour, 1 day, 1 week, 2 weeks and 4 weeks of the formation of thrombus at a 2.0 T MR unit. The signal intensities of the thrombus and adjacent muscles were compared subjectively, and the signal intensity ratio was compared objectively by the measurement of the signal intensities using a cursor. The MRI findings were compared with histologic findings. The signal intensities of static blood were hyperintense in all pulse sequences, and those of 2 hour, 1 day and 1 week old thrombi were hyperintense in all pulse sequence. The number of experimental thrombi which showed isointensity on T1- and T2-weighted image, and hyperintensity on gradient echo image increased as thrombi aged. The signal intensities of 2 week old thrombus were isointense on T1-weighted image, hyperintense on T2-weighted image, and hyperintense on gradient echo image, while those of 4 week old thrombus were isointense on T1-weighted and T2-weighted image, and hypointense on gradient echo image in most experimental thrombi. There was a tendency to decrease in a signal intensity ratio as thrombi aged on T1-weighted, T2-weighted and gradient echo images(p<0.01). Histologically, thrombus was not formed and lumen was filled with many red blood cells(RBCs) in 2 hour old specimen, but fibrin mesh was visible and RBCs decreased in number in 1 day old specimen. In 1 week old specimen, vessel was contrasted and lumen was filled with thrombus
-
International Nuclear Information System (INIS)
Heyns A du, P.; Badenhorst, P.N.; Loetter, M.G.P.; Pieters, H.; Wessels, P.; Kotze, H.F.
1986-01-01
Mean platelet survival and turnover were simultaneously determined with autologous 111In-labeled platelets (111In-AP) and homologous 51Cr-labeled platelets (51Cr-HP) in ten patients with chronic immune thrombocytopenic purpura (ITP). In vivo redistribution of the 111In-AP was quantitated with a scintillation camera and computer-assisted image analysis. The patients were divided into two groups: those with splenic platelet sequestration (spleen-liver 111In activity ratio greater than 1.4), and those with diffuse sequestration in the reticuloendothelial system. The latter patients had more severe ITP reflected by pronounced thrombocytopenia, decreased platelet turnover, and prominent early hepatic platelet sequestration. Mean platelet life span estimated with 51Cr-HP was consistently shorter than that of 111In-AP. Platelet turnover determined with 51Cr-HP was thus over-estimated. The difference in results with the two isotope labels was apparently due to greater in vivo elution of 51Cr. Although the limitations of the techniques should be taken into account, these findings indicate that platelet turnover is not always normal or increased in ITP, but is low in severe disease. We suggest that this may be ascribed to damage to megakaryocytes by antiplatelet antibody. The physical characteristics in 111In clearly make this radionuclide superior to 51Cr for the study of platelet kinetics in ITP
-
Blood compatibility of AAc, HEMA, and PEGMA-grafted cellulose film
International Nuclear Information System (INIS)
Nho, Young Chang.; Kwon, Oh Hyun
2003-01-01
To improve surface blood compatibility on cellulose film for hemodialysis, acrylic acid, 2-hydroxyethyl methacrylate and three kinds of polyethylene glycol methacrylates were grafted onto the cellulose film surface by radiation grafting technique. Heparin was introduced onto the grafted cellulose film surfaces. The grafting and heparinization were confirmed by Fourier transform infrared spectroscopy in the attenuated total reflectance mode and electron spectroscopy for chemical analysis. The blood compatibility of the modified cellulose film was examined by the determination of platelet adhesion and thrombus formation
-
International Nuclear Information System (INIS)
Rand, M.L.; Packham, M.A.; Mustard, J.F.
1983-01-01
The origin of the density heterogeneity of platelets was studied by measuring the survival of density subpopulations of rabbit platelets separated by discontinuous Stractan density gradient centrifugation. When a total population of 51 Cr-labelled platelets was injected into recipient rabbits, the relative specific radioactivity of the most dense platelets decreased rapidly. In contrast, that of the least dense platelets had not changed 24 hr after injection, and then decreased slowly. To distinguish between the possibilities that most dense platelets are cleared from the circulation more quickly than least dense platelets or that platelets decrease in density as they age in the circulation, the concurrent survival of least dense and most dense platelets, labelled with either 51 Cr or 111 In-labelled total platelet populations, determined concurrently in the same rabbits, are identical, calculated from 1 hr values as 100%. However, the 1-hr recovery of 111 In-labelled platelets was slightly but significantly less than that of 51 Cr-labelled platelets. Therefore, researchers studied the survival of 51 Cr-labelled least dense and 111 In-labelled most dense platelets as well as that of 111 In-labelled least dense and 51 Cr-labelled most dense platelets. Mean 1-hr recovery of least dense platelets, labelled with either isotope (78% +/- 7%, SD) was similar to that of most dense platelets, labelled with either isotope (77% +/- 8%; SD). Mean survival of least dense platelets was 47.3 +/- 18.7 hr (SD), which was significantly less than that of most dense platelets (76.1 +/- 21.6 hr; SD) (p less than 0.0025). These results indicate that platelets decrease in buoyant density as they age in the circulation and that most dense platelets are enriched in young platelets, and least dense in old
-
Antimicrobial effect of platelet-rich plasma and platelet-rich fibrin.
Badade, Pallavi S; Mahale, Swapna A; Panjwani, Alisha A; Vaidya, Prutha D; Warang, Ayushya D
2016-01-01
Platelet concentrates have been extensively used in a variety of medical fields to promote soft- and hard-tissue regeneration. The significance behind their use lies in the abundance of growth factors (GFs) in platelets α-granules that promote wound healing. Other than releasing a pool of GFs upon activation, platelets also have many features that indicate their role in the anti-infective host defense. The aim of this study is to evaluate the antimicrobial activities of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) against periodontal disease-associated bacteria. Blood samples were obtained from ten adult male patients. PRP and PRF were procured using centrifugation. The antimicrobial activity of PRP and PRF was evaluated by microbial culturing using bacterial strains of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. P. gingivalis and A. actinomycetemcomitans were inhibited by PRP but not by PRF. PRP is a potentially useful substance in the fight against periodontal pathogens. This might represent a valuable property in adjunct to the enhancement of tissue regeneration.
-
The normal number of platelets in the blood is 150,000 to 400,000 platelets per microliter (mcL) or 150 to 400 × 10 9 /L. Normal value ranges may vary slightly. Some lab use different measurements or ...
-
DEFF Research Database (Denmark)
Moghimi, Seyed Moein; Hunter, Alan Christy; Peer, Dan
2016-01-01
Here we critically examine whether coating of nanoparticles with platelet membranes can truly disguise them against recognition by elements of the innate immune system. We further assess whether the "cloaking technology" can sufficiently equip nanoparticles with platelet-mimicking functionalities...
-
Daga, Shruti; Shepherd, James G.; Callaghan, J. Garreth S.; Hung, Rachel K.Y.; Dawson, Dana K.; Padfield, Gareth J.; Hey, Shi Y.; Cartwright, Robyn A.; Newby, David E.; Fitzgerald, J. Ross
2011-01-01
Cardiac vegetations result from bacterium–platelet adherence, activation and aggregation, and are associated with increased morbidity and mortality in infective endocarditis. The GPIIb/IIIa and FcγRIIa platelet receptors play a central role in platelet adhesion, activation and aggregation induced by endocarditis pathogens such as Staphylococcus aureus, but the influence of known polymorphisms of these receptors on the pathogenesis of infective endocarditis is unknown. We determined the GPIIIa platelet antigen PlA1/A2 and FcγRIIa H131R genotype of healthy volunteers (n = 160) and patients with infective endocarditis (n = 40), and investigated the influence of these polymorphisms on clinical outcome in infective endocarditis and S. aureus–platelet interactions in vitro. Platelet receptor genotype did not correlate with development of infective endocarditis, vegetation characteristics on echocardiogram or the composite clinical end-point of embolism, heart failure, need for surgery or mortality (P > 0.05 for all), even though patients with the GPIIIa PlA1/A1 genotype had increased in vivo platelet activation (P = 0.001). Furthermore, neither GPIIIa PlA1/A2 nor FcγRIIa H131R genotype influenced S. aureus-induced platelet adhesion, activation or aggregation in vitro (P > 0.05). Taken together, our data suggest that the GPIIIa and FcγRIIa platelet receptor polymorphisms do not influence S. aureus–platelet interactions in vitro or the clinical course of infective endocarditis. PMID:21044892
-
Sergeeva, N S; Shanskii, Ya D; Sviridova, I K; Karalkin, P A; Kirsanova, V A; Akhmedova, S A; Kaprin, A D
2016-11-01
Platelet lysate prepared from donor platelet concentrate and pooled according to a developed technique stimulates migration of multipotent mesenchymal stromal cells of the human adipose tissue and promotes healing of the monolayer defect in cultures of human fibroblasts and multipotent mesenchymal stromal cells in vitro in concentrations close those of fetal calf serum (5-10%). Lysate of platelets from platelet-rich rat blood plasma stimulated healing of the skin defect by promoting epithelialization and granulation tissue formation. The regenerative properties of platelet lysate in vivo increased with increasing its concentration.
-
Congenital platelet function defects
... pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital ... Congenital platelet function defects are bleeding disorders that cause reduced platelet function. Most of the time, people with these disorders have ...
-
International Nuclear Information System (INIS)
Fayyaz, A.; Iqbal, M.W.
2014-01-01
Introduction: Patients with mitral stenosis (MS) having atrial fibrillation (AF) are more prone to develop left atrial (LA) thrombus. Systemic embolism, related to LA thrombus is a well-known risk of Percutaneous Mitral Balloon Valvotomy (PMBV) of the mitral valve. Therefore presence of LA thrombus is a contraindication to PMBV. Objective: Objective of this study was to detect the frequency of LA thrombus by transesophageal echocardiography (TEE) in patients of tight MS in whom transthoracic echocardiography (TTE) could not detect any LA thrombus. Patients and Methods: In this cross sectional study, we took 100 indoor patients with tight MS on non-probability consecutive sampling. Data was collected after meeting inclusion criteria. Patients were taken in this study after acquiring written informed consent. Symptoms were inquired from all patients and functional status was assessed by New York Heart Association class. Unstable patients were medically managed before the procedure. TEE was done on the same day before undergoing PMBV to look for clot in LA. Results: The mean age of the patients was 32.20 years and SD was 11.3 years. There were 36(36%) male patients and 64(64%) female patients. LA thrombus was present in 40% of patients on TEE out of which 19 were male patients (52.77%) and 21 were female patients (32.81%). Conclusion: Patients with mitral stenosis having AF are more prone to develop LA thrombus. In this study, the frequency of LA thrombus was 40% recorded, which is high. Due to the potential risk of embolization, it is strongly recommended to perform TEE in patients with normal TTE study before undergoing PMBV. The presence of a LA thrombus should be considered a contraindication to the PMBV of the mitral valve. (author)
-
OP9 bone marrow stroma cells differentiate into megakaryocytes and platelets.
Directory of Open Access Journals (Sweden)
Yumiko Matsubara
Full Text Available Platelets are essential for hemostatic plug formation and thrombosis. The mechanisms of megakaryocyte (MK differentiation and subsequent platelet production from stem cells remain only partially understood. The manufacture of megakaryocytes (MKs and platelets from cell sources including hematopoietic stem cells and pluripotent stem cells have been highlighted for studying the platelet production mechanisms as well as for the development of new strategies for platelet transfusion. The mouse bone marrow stroma cell line OP9 has been widely used as feeder cells for the differentiation of stem cells into MK lineages. OP9 cells are reported to be pre-adipocytes. We previously reported that 3T3-L1 pre-adipocytes differentiated into MKs and platelets. In the present study, we examined whether OP9 cells differentiate into MKs and platelets using MK lineage induction (MKLI medium previously established to generate MKs and platelets from hematopoietic stem cells, embryonic stem cells, and pre-adipocytes. OP9 cells cultured in MKLI medium had megakaryocytic features, i.e., positivity for surface markers CD41 and CD42b, polyploidy, and distinct morphology. The OP9-derived platelets had functional characteristics, providing the first evidence for the differentiation of OP9 cells into MKs and platelets. We then analyzed gene expressions of critical factors that regulate megakaryopoiesis and thrombopoiesis. The gene expressions of p45NF-E2, FOG, Fli1, GATA2, RUNX1, thrombopoietin, and c-mpl were observed during the MK differentiation. Among the observed transcription factors of MK lineages, p45NF-E2 expression was increased during differentiation. We further studied MK and platelet generation using p45NF-E2-overexpressing OP9 cells. OP9 cells transfected with p45NF-E2 had enhanced production of MKs and platelets. Our findings revealed that OP9 cells differentiated into MKs and platelets in vitro. OP9 cells have critical factors for megakaryopoiesis and
-
Pappas, Anthony J; Knight, Stephen W; McLean, Katherine Zanyk; Bork, Susan; Kurz, Michael C; Sawyer, Kelly N
2016-09-01
Venous thromboembolism, including pulmonary embolism (PE), is a common disease identified in the emergency department that carries significant morbidity and mortality. In its most severe form, PE is fulminant and characterized by cardiac arrest and death. In the midst of risk-stratifying PE by using echocardiography to assess right ventricular function, thrombus-in-transit (free-floating clot in the right atrium or ventricle) may be seen. We present a case of a 49-year-old man diagnosed with an acute saddle PE who was incidentally found to have a thrombus-in-transit and patent foramen ovale and required open thrombectomy. Identification of these additional potentially life-threatening features was possible only due to our availability of risk-stratification resources, specifically bedside echocardiography. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Albeit rare, with a reported incidence estimated at 4%, the presence of thrombus-in-transit may change emergent clinical management. A multidisciplinary team of resources should be considered emergently as part of a hospital-based PE system of care. Copyright © 2016 Elsevier Inc. All rights reserved.