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Sample records for cardiomyocyte contractile dysfunction

  1. Natural Antioxidant-Isoliquiritigenin Ameliorates Contractile Dysfunction of Hypoxic Cardiomyocytes via AMPK Signaling Pathway

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    Xiaoyu Zhang

    2013-01-01

    Full Text Available Isoliquiritigenin (ISL, a simple chalcone-type flavonoid, is derived from licorice compounds and is mainly present in foods, beverages, and tobacco. Reactive oxygen species (ROS is a critical factor involved in modulating cardiac stress response signaling during ischemia and reperfusion. We hypothesize that ISL as a natural antioxidant may protect heart against ischemic injury via modulating cellular redox status and regulating cardioprotective signaling pathways. The fluorescent probe H2DCFDA was used to measure the level of intracellular ROS. The glucose uptake was determined by 2-deoxy-D-glucose-3H accumulation. The IonOptix System measured the contractile function of isolated cardiomyocytes. The results demonstrated that ISL treatment markedly ameliorated cardiomyocytes contractile dysfunction caused by hypoxia. ISL significantly stimulated cardioprotective signaling, AMP-activated protein kinase (AMPK, and extracellular signal-regulated kinase (ERK signaling pathways. The ROS fluorescent probe H2DCFDA determination indicated that ISL significantly reduced cardiac ROS level during hypoxia/reoxygenation. Moreover, ISL reduced the mitochondrial potential (Δψ of isolated mouse cardiomyocytes. Taken together, ISL as a natural antioxidant demonstrated the cardioprotection against ischemic injury that may attribute to the activation of AMPK and ERK signaling pathways and balance of cellular redox status.

  2. Facilitated ethanol metabolism promotes cardiomyocyte contractile dysfunction through autophagy in murine hearts

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    Guo, Rui; Hu, Nan; Kandadi, Machender R.; Ren, Jun

    2012-01-01

    Chronic drinking leads to myocardial contractile dysfunction where ethanol metabolism plays an essential role. Acetaldehyde, the main ethanol metabolite, mediates alcohol-induced cell injury although the underlying mechanism is still elusive. This study was designed to examine the mechanism involved in accelerated ethanol metabolism-induced cardiac defect with a focus on autophagy. Wild-type FVB and cardiac-specific overexpression of alcohol dehydrogenase mice were placed on a 4% nutrition-balanced alcohol diet for 8 weeks. Myocardial histology, immunohistochemistry, autophagy markers and signal molecules were examined. Expression of micro RNA miR-30a, a potential target of Beclin 1, was evaluated by real-time PCR. Chronic alcohol intake led to cardiac acetaldehyde accumulation, hypertrophy and overt autophagosome accumulation (LC3-II and Atg7), the effect of which was accentuated by ADH. Signaling molecules governing autophagy initiation including class III PtdIns3K, phosphorylation of mTOR and p70S6K were enhanced and dampened, respectively, following alcohol intake. These alcohol-induced signaling responses were augmented by ADH. ADH accentuated or unmasked alcohol-induced downregulation of Bcl-2, Bcl-xL and MiR-30a. Interestingly, ADH aggravated alcohol-induced p62 accumulation. Autophagy inhibition using 3-MA abolished alcohol-induced cardiomyocyte contractile anomalies. Moreover, acetaldehyde led to cardiomyocyte contractile dysfunction and autophagy induction, which was ablated by 3-MA. Ethanol or acetaldehyde increased GFP-LC3 puncta in H9c2 cells, the effect of which was ablated by 3-MA but unaffected by lysosomal inhibition using bafilomycin A1, E64D and pepstatin A. In summary, these data suggested that facilitated acetaldehyde production via ADH following alcohol intake triggered cardiac autophagosome formation along with impaired lysosomal degradation, en route to myocardial defect. PMID:22441020

  3. Fractalkine depresses cardiomyocyte contractility.

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    David Taube

    Full Text Available BACKGROUND: Our laboratory reported that male mice with cardiomyocyte-selective knockout of the prostaglandin E2 EP4 receptor sub-type (EP4 KO exhibit reduced cardiac function. Gene array on left ventricles (LV showed increased fractalkine, a chemokine implicated in heart failure. We therefore hypothesized that fractalkine is regulated by PGE2 and contributes to depressed contractility via alterations in intracellular calcium. METHODS: Fractalkine was measured in LV of 28-32 week old male EP4 KO and wild type controls (WT by ELISA and the effect of PGE2 on fractalkine secretion was measured in cultured neonatal cardiomyocytes and fibroblasts. The effect of fractalkine on contractility and intracellular calcium was determined in Fura-2 AM-loaded, electrical field-paced cardiomyocytes. Cardiomyocytes (AVM from male C57Bl/6 mice were treated with fractalkine and responses measured under basal conditions and after isoproterenol (Iso stimulation. RESULTS: LV fractalkine was increased in EP4 KO mice but surprisingly, PGE2 regulated fractalkine secretion only in fibroblasts. Fractalkine treatment of AVM decreased both the speed of contraction and relaxation under basal conditions and after Iso stimulation. Despite reducing contractility after Iso stimulation, fractalkine increased the Ca(2+ transient amplitude but decreased phosphorylation of cardiac troponin I, suggesting direct effects on the contractile machinery. CONCLUSIONS: Fractalkine depresses myocyte contractility by mechanisms downstream of intracellular calcium.

  4. Toll-like receptor 4 knockout alleviates paraquat-induced cardiomyocyte contractile dysfunction through an autophagy-dependent mechanism.

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    Wang, Shuyi; Zhu, Xiaoling; Xiong, Lize; Zhang, Yingmei; Ren, Jun

    2016-08-22

    Paraquat, a quarternary nitrogen herbicide, is a toxic prooxidant leading to multi-organ failure including the heart although the underlying mechanism remains poorly understood. This study was designed to examine the role of the innate proinflammatory mediator toll-like receptor 4 (TLR4) in paraquat-induced cardiac contractile anomalies and the underlying mechanisms involved with a focus on autophagy, a conservative machinery governing protein and organelle degradation and recycling for cardiac homeostasis. Wild-type (WT) and TLR4 knockout (TLR4(-/-)) mice were challenged with paraquat (45mg/kg, i.p.) for 48h. Paraquat challenge did not affect mRNA levels of TLR2, TLR4 and TLR9 in WT mice nor did paraquat treatment alter TREM-1 levels. Paraquat challenge elicited cardiac mechanical defects including compromised cardiomyocyte contractile function, intracellular Ca(2+) handling, and overt autophagy as manifested by increased LC3BII-to-LC3BI ratio, Atg5, Atg7 and p62 levels. Interestingly, TLR4 knockout significantly attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) derangement as well as alterations of autophagy markers. Paraquat-elicited changes in cardiac autophagy markers (LC3BII, LC3BII-to-LC3BI ratio and p62) were augmented by lysosomal inhibition using bafilomycin A1 in WT mice. TLR4 knockout significantly attenuated or negated paraquat-elicited increase in LC3BII, LC3BII-to-LC3BI ratio and p62 levels in the presence of lysosomal inhibition. In addition, paraquat challenge promoted phosphorylation of AMPK while suppressing the phosphorylation of mTOR and ULK1 (the autophagy inhibitory Ser(757)), the effects of which were significantly attenuated by TLR4 ablation. In vitro study revealed that AMPK activation using AICAR or mTOR inhibition using rapamycin effectively negated the beneficial cardiomyocyte mechanical effects of TLR4 inhibition (CLI-095) against paraquat toxicity, supporting a permissive role for AMPK-mTOR in TLR4 inhibition

  5. Contractile Dysfunction in Sarcomeric Hypertrophic Cardiomyopathy.

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    MacIver, David H; Clark, Andrew L

    2016-09-01

    The pathophysiological mechanisms underlying the clinical phenotype of sarcomeric hypertrophic cardiomyopathy are controversial. The development of cardiac hypertrophy in hypertension and aortic stenosis is usually described as a compensatory mechanism that normalizes wall stress. We suggest that an important abnormality in hypertrophic cardiomyopathy is reduced contractile stress (the force per unit area) generated by myocardial tissue secondary to abnormalities such as cardiomyocyte disarray. In turn, a progressive deterioration in contractile stress provokes worsening hypertrophy and disarray. A maintained or even exaggerated ejection fraction is explained by the increased end-diastolic wall thickness producing augmented thickening. We propose that the nature of the hemodynamic load in an individual with hypertrophic cardiomyopathy could determine its phenotype. Hypertensive patients with hypertrophic cardiomyopathy are more likely to develop exaggerated concentric hypertrophy; athletic individuals an asymmetric pattern; and inactive individuals a more apical hypertrophy. The development of a left ventricular outflow tract gradient and mitral regurgitation may be explained by differential regional strain resulting in mitral annular rotation.

  6. Short-Chain Fatty Acid Propionate Alleviates Akt2 Knockout-Induced Myocardial Contractile Dysfunction

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    Linlin Li

    2012-01-01

    Full Text Available Background and Aims. Dysregulation of Akt has been implicated in diseases such as cancer and diabetes, although little is known about the role of Akt deficiency on cardiomyocyte contractile function. This study was designed to examine the effect of Akt2 knockout-induced cardiomyocyte contractile response and the effect of dietary supplementation of short-chain fatty acid propionate on Akt2 knockout-induced cardiac dysfunction, if any. Methods and Results. Adult male wild-type (WT and Akt2 knockout mice were treated with propionate (0.3 g/kg, p.o. or vehicle for 7 days. Oral glucose tolerance test (OGTT was performed. Cardiomyocyte contractile function and mitochondrial membrane potential were assessed. Expression of insulin-signaling molecules Akt, PTEN, GSK3β, and eNOS receptors for short-chain fatty acids GPR41, and GPR43 as well as protein phosphatase PP2AA, PP2AB, PP2C were evaluated using Western blot analysis. Our results revealed that Akt2 knockout led to overt glucose intolerance, compromised cardiomyocyte contractile function (reduced peak shortening and maximal velocity of shortening/relengthening as well as prolonged relengthening, loss of mitochondrial membrane potential, decreased GPR41 and elevated GPR43 expression, all of which, with the exception of glucose intolerance and elevated GPR43 level, were significantly attenuated by propionate. Neither Akt2 knockout nor propionate affected the expression of protein phosphatases, eNOS, pan, and phosphorylated PTEN and GSK3β. Conclusions. Taken together, these data depicted that Akt2 knockout may elicit cardiomyocyte contractile and mitochondrial defects and a beneficial role of propionate or short-chain fatty acids against Akt2 deficiency-induced cardiac anomalies.

  7. Cardiac-specific catalase overexpression rescues anthrax lethal toxin-induced cardiac contractile dysfunction: role of oxidative stress and autophagy

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    Kandadi Machender R

    2012-11-01

    Full Text Available Abstract Background Lethal and edema toxins secreted by Bacillus anthracis during anthrax infection were found to incite serious cardiovascular complications. However, the underlying mechanisms in anthrax lethal toxin-induced cardiac anomalies remain unknown. This study was designed to evaluate the impact of antioxidant enzyme catalase in anthrax lethal toxin-induced cardiomyocyte contractile dysfunction. Methods Wild type (WT and cardiac-specific catalase overexpression mice were challenged with lethal toxin (2 μg/g, intraperotineally (i.p.. Cardiomyocyte contractile and intracellular Ca2+ properties were assessed 18 h later using an IonOptix edge-detection system. Proteasome function was assessed using chymotrypsin-like and caspase-like activities. GFP-LC3 puncta and Western blot analysis were used to evaluate autophagy and protein ubiquitination. Results Lethal toxin exposure suppressed cardiomyocyte contractile function (suppressed peak shortening, maximal velocity of shortening/re-lengthening, prolonged duration of shortening/re-lengthening, and impaired intracellular Ca2+ handling, the effects of which were alleviated by catalase. In addition, lethal toxin triggered autophagy, mitochondrial and ubiquitin-proteasome defects, the effects of which were mitigated by catalase. Pretreatment of cardiomyocytes from catalase mice with the autophagy inducer rapamycin significantly attenuated or ablated catalase-offered protection against lethal toxin-induced cardiomyocyte dysfunction. On the other hand, the autophagy inhibitor 3-MA ablated or significantly attenuated lethal toxin-induced cardiomyocyte contractile anomalies. Conclusions Our results suggest that catalase is protective against anthrax lethal toxin-induced cardiomyocyte contractile and intracellular Ca2+ anomalies, possibly through regulation of autophagy and mitochondrial function.

  8. Formation of mitochondrial apparatus of contractile cardiomyocytes during normal and hypoxic injury of cardi-ogenesis

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    Ivanchenko M.V.; Tverdokhlib I.V.

    2013-01-01

    Changes of cardiomyocytes mitochondrial apparatus can be marked as the main factors which are the basis of various forms of cardiovascular disease, but the dynamics of morphogenetic rearrangements heart mitochondria are poorly researched under normal conditions and under the influence of harmful factors. Mitochondria of contractile cardiomyocytes are different in their morphology and localization in the cell, the biochemical properties and are able to form differently association with other i...

  9. Contractile apparatus dysfunction early in thepathophysiology of diabetic cardiomyopathy

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Diabetes mellitus significantly increases the risk ofcardiovascular disease and heart failure in patients.Independent of hypertension and coronary arterydisease, diabetes is associated with a specific cardiomyopathy,known as diabetic cardiomyopathy (DCM).Four decades of research in experimental animalmodels and advances in clinical imaging techniquessuggest that DCM is a progressive disease, beginningearly after the onset of type 1 and type 2 diabetes,ahead of left ventricular remodeling and overt diastolicdysfunction. Although the molecular pathogenesis ofearly DCM still remains largely unclear, activation ofprotein kinase C appears to be central in driving theoxidative stress dependent and independent pathwaysin the development of contractile dysfunction. Multiplesubcellular alterations to the cardiomyocyte are nowbeing highlighted as critical events in the early changesto the rate of force development, relaxation and stabilityunder pathophysiological stresses. These changes includeperturbed calcium handling, suppressed activity ofaerobic energy producing enzymes, altered transcriptionaland posttranslational modification of membrane andsarcomeric cytoskeletal proteins, reduced actin-myosincross-bridge cycling and dynamics, and changed myofilamentcalcium sensitivity. In this review, we will presentand discuss novel aspects of the molecular pathogenesisof early DCM, with a special focus on the sarcomericcontractile apparatus.

  10. Effects of Substrate Mechanics on Contractility of Cardiomyocytes Generated from Human Pluripotent Stem Cells

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    Laurie B. Hazeltine

    2012-01-01

    Full Text Available Human pluripotent stem cell (hPSC- derived cardiomyocytes have potential applications in drug discovery, toxicity testing, developmental studies, and regenerative medicine. Before these cells can be reliably utilized, characterization of their functionality is required to establish their similarity to native cardiomyocytes. We tracked fluorescent beads embedded in 4.4–99.7 kPa polyacrylamide hydrogels beneath contracting neonatal rat cardiomyocytes and cardiomyocytes generated from hPSCs via growth-factor-induced directed differentiation to measure contractile output in response to changes in substrate mechanics. Contraction stress was determined using traction force microscopy, and morphology was characterized by immunocytochemistry for α-actinin and subsequent image analysis. We found that contraction stress of all types of cardiomyocytes increased with substrate stiffness. This effect was not linked to beating rate or morphology. We demonstrated that hPSC-derived cardiomyocyte contractility responded appropriately to isoprenaline and remained stable in culture over a period of 2 months. This study demonstrates that hPSC-derived cardiomyocytes have appropriate functional responses to substrate stiffness and to a pharmaceutical agent, which motivates their use in further applications such as drug evaluation and cardiac therapies.

  11. Changes of mitochondria in the contractile cardiomyocytes during postnatal rat ontogenesis

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    Kozlov S.V.

    2014-12-01

    Full Text Available Background. CVDs are the number 1 cause of death globally: more people die annually from CVDs than from any other cause. An estimated 17.5 million people died from CVDs in 2012, representing 31% of all global deaths. Of these deaths, an estimated 7.4 million were due to coronary heart disease and 6.7 million were due to stroke. Over three quarters of CVD deaths take place in low- and middle-income countries. Objective. Ultrastructural analysis of mitochondria in the rat contractile cardiomyocytes during postnatal ontogenesis. Methods. As the object of the study were used neonatal rat hearts, on the 5th, 10th, 15th, 30th days of life and mature animals. Hearts were investigated by the transmission electron microscopy. Volume density and numerical density of mitochondria were estimated. The Paired Student’s t-test was applied. Results. Was conducted a comprehensive ultrastructural analysis of mitochondria contractile cardiomyocytes, which allowed us to determine changes in the qualitative and quantitative parameters of mitochondria during postnatal ontogenesis, and helps to explain the dynamics and the development of mitochondria heart muscles cells after birth. Conclusion. It was shown that from the 1st to the 5th day there was a significant increase in volume density of mitochondria, which was accompanied by the increasing complexity of the ultrastructural organization of organelles. Following 20th day of postnatal ontogenesis mitochondrial structure was approaching the definitive condition and on the 30th day was the same as the mature myocardium. Citation: Kozlov SV, Mayevsky AE, Mіshalov VD, Sulayeva ON. [Changes of mitochondria in the contractile cardiomyocytes during postnatal rat ontogenesis]. Morphologia. 2014;8(4:37-42. Russian.

  12. Human embryonic stem cell derived mesenchymal progenitors express cardiac markers but do not form contractile cardiomyocytes.

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    Christophe M Raynaud

    Full Text Available Mesenchymal progenitors or stromal cells have shown promise as a therapeutic strategy for a range of diseases including heart failure. In this context, we explored the growth and differentiation potential of mesenchymal progenitors (MPs derived in vitro from human embryonic stem cells (hESCs. Similar to MPs isolated from bone marrow, hESC derived MPs (hESC-MPs efficiently differentiated into archetypical mesenchymal derivatives such as chondrocytes and adipocytes. Upon treatment with 5-Azacytidine or TGF-β1, hESC-MPs modified their morphology and up-regulated expression of key cardiac transcription factors such as NKX2-5, MEF2C, HAND2 and MYOCD. Nevertheless, NKX2-5+ hESC-MP derivatives did not form contractile cardiomyocytes, raising questions concerning the suitability of these cells as a platform for cardiomyocyte replacement therapy. Gene profiling experiments revealed that, although hESC-MP derived cells expressed a suite of cardiac related genes, they lacked the complete repertoire of genes associated with bona fide cardiomyocytes. Our results suggest that whilst agents such as TGF-β1 and 5-Azacytidine can induce expression of cardiac related genes, but treated cells retain a mesenchymal like phenotype.

  13. Paradoxical effects of ginkgolide B on cardiomyocyte contractile function in normal and high-glucose environments

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    Jihye KIM; Qun LI; Cindy X FANG; Jun REN

    2006-01-01

    Aim: Ginkgo biloba extract is a natural product used widely for cerebral and cardiovascular diseases. It is mainly composed of terpene lactones (ginkgolide A and B) and flavone glycosides (eg quercetin and kaempferol).To better understand the cardiac electromechanical action of Ginkgo biloba extract in normal and diabetic states, this study was designed to examine the effect of ginkgolide B on cardiomyocyte contractile function under normal and high-glucose environments. Methods: Isolated adult rat ventricular myocytes were cultured for 6 h in a serum-free medium containing either normal (NG;5.5 mmol/L) or high (HG;25.5 mmol/L) glucose with or without ginkgolide B (0.5-2.0μg/mL). Mechanical properties were evaluated using the IonOptix MyoCam system. Contractile properties analyzed included peak shortening (PS),maximal velocity of shortening/relengthening (+dl/dt),time-to-PS (TPS) and time-to-90% relengthening (TR90). Levels of essential Ca2+ regulatory proteins sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA2a),phospholamban (PLB) and Na+-Ca2+ exchanger (NCX) were assessed by Western blotting. Results: Ginkgolide B nullified HG-induced prolongation in TR90. However, ginkgolide B depressed PS.±dl/dt and shortened TPS in NG and HG cells. Ginkgolide B also prolonged TR90 in NG cells. Western blot analysis revealed that HG upregulated SERCA2a and downregulated PLB expression without affecting that of NCX. Ginkgolide B disrupted the NG-HG response pattern in SERCA2a and NCX without affecting that of PLB. Conclusion: Ginkgolide B affects cardiomyocyte contractile function under NG or HG environments in a paradoxical manner, which may be attributed to uneven action on Ca2+ regulatory proteins under NG and HG conditions.

  14. Exenatide Reduces Tumor Necrosis Factor-α-induced Apoptosis in Cardiomyocytes by Alleviating Mitochondrial Dysfunction

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    Yuan-Yuan Cao; Zhang-Wei Chen; Yan-Hua Gao; Xing-Xu Wang; Jian-Ying Ma; Shu-Fu Chang; Ju-Ying Qian

    2015-01-01

    Background: Tumor necrosis factor-α (TNF-α) plays an important role in progressive contractile dysfunction in several cardiac diseases.The cytotoxic effects of TNF-α are suggested to be partly mediated by reactive oxygen species (ROS)-and mitochondria-dependent apoptosis.Glucagon-like peptide-1 (GLP-1) or its analogue exhibits protective effects on the cardiovascular system.The objective of the study was to assess the effects of exenatide, a GLP-1 analogue, on oxidative stress, and apoptosis in TNF-c-treated cardiomyocytes in vitro.Methods: Isolated neonatal rat cardiomyocytes were divided into three groups: Control group, with cells cultured in normal conditions without intervention;TNF-α group, with cells incubated with TNF-c (40 ng/ml) for 6, 12, or 24 h without pretreatment with exenatide;and exenatide group, with cells pretreated with exenatide (100 nmol/L) 30 mins before TNF-α (40 ng/ml) stimulation.We evaluated apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry, measured ROS production and mitochondrial membrane potential (MMP) by specific the fluorescent probes, and assessed the levels of proteins by Western blotting for all the groups.Results: Exenatide pretreatment significantly reduced cardiomyocyte apoptosis as measured by flow cytometry and TUNEL assay at 12 h and 24 h.Also, exenatide inhibited excessive ROS production and maintained MMP.Furthermore, declined cytochrome-c release and cleaved caspase-3 expression and increased bcl-2 expression with concomitantly decreased Bax activation were observed in exenatide-pretreated cultures.Conclusion: These results suggested that exenatide exerts a protective effect on cardiomyocytes, preventing TNF-α-induced apoptosis;the anti-apoptotic effects may be associated with protection of mitochondrial function.

  15. Formation of mitochondrial apparatus of contractile cardiomyocytes during normal and hypoxic injury of cardi-ogenesis

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    Ivanchenko M.V.

    2013-01-01

    Full Text Available Changes of cardiomyocytes mitochondrial apparatus can be marked as the main factors which are the basis of various forms of cardiovascular disease, but the dynamics of morphogenetic rearrangements heart mitochondria are poorly researched under normal conditions and under the influence of harmful factors. Mitochondria of contractile cardiomyocytes are different in their morphology and localization in the cell, the biochemical properties and are able to form differently association with other intracellular structures. Question of the relationship between function and heterogeneity of regional specialization of mitochondria and the realization of the heterogeneity in the cell and the degree of their dependence on the disease during ontogeny is important and relevant. There are relatively few ultrastructural studies that investigate adaptive techniques and alternative processes in the mitochondria of atrial and ventricular myocardium under prenatal hypoxia during the development of the myocardium. It is interesting to find mechanisms for the implementation of the ultrastructural changes in the mitochondrial apparatus and extracellular tissue levels in hypoxic conditions on the stages of ontogeny.

  16. Anthrax lethal toxin suppresses murine cardiomyocyte contractile function and intracellular Ca2+ handling via a NADPH oxidase-dependent mechanism.

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    Machender R Kandadi

    Full Text Available OBJECTIVES: Anthrax infection is associated with devastating cardiovascular sequelae, suggesting unfavorable cardiovascular effects of toxins originated from Bacillus anthracis namely lethal and edema toxins. This study was designed to examine the direct effect of lethal toxins on cardiomyocyte contractile and intracellular Ca(2+ properties. METHODS: Murine cardiomyocyte contractile function and intracellular Ca(2+ handling were evaluated including peak shortening (PS, maximal velocity of shortening/ relengthening (± dL/dt, time-to-PS (TPS, time-to-90% relengthening (TR(90, intracellular Ca(2+ rise measured as fura-2 fluorescent intensity (ΔFFI, and intracellular Ca(2+ decay rate. Stress signaling and Ca(2+ regulatory proteins were assessed using Western blot analysis. RESULTS: In vitro exposure to a lethal toxin (0.05-50 nM elicited a concentration-dependent depression on cardiomyocyte contractile and intracellular Ca(2+ properties (PS, ± dL/dt, ΔFFI, along with prolonged duration of contraction and intracellular Ca(2+ decay, the effects of which were nullified by the NADPH oxidase inhibitor apocynin. The lethal toxin significantly enhanced superoxide production and cell death, which were reversed by apocynin. In vivo lethal toxin exposure exerted similar time-dependent cardiomyocyte mechanical and intracellular Ca(2+ responses. Stress signaling cascades including MEK1/2, p38, ERK and JNK were unaffected by in vitro lethal toxins whereas they were significantly altered by in vivo lethal toxins. Ca(2+ regulatory proteins SERCA2a and phospholamban were also differentially regulated by in vitro and in vivo lethal toxins. Autophagy was drastically triggered although ER stress was minimally affected following lethal toxin exposure. CONCLUSIONS: Our findings indicate that lethal toxins directly compromised murine cardiomyocyte contractile function and intracellular Ca(2+ through a NADPH oxidase-dependent mechanism.

  17. Insulin improves cardiomyocyte contractile function through enhancement of SERCA2a activity in simulated ischemia/reperfusion

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    Jie YU; Hai-feng ZHANG; Feng WU; Qiu-xia LI; Heng MA; Wen-yi GUO; Hai-chang WANG; Feng GAO

    2006-01-01

    Aim: Insulin exerts anti-apoptotic effects in both cardiomyocytes and coronary endothelial cells following ischemia/reperfusion (I/R) via the Akt-endothelial nitric oxide synthase survival signal pathway. This important insulin signaling might further contribute to the improvement of cardiac function after reperfusion. In this study, we tested the hypothesis that sarcoplasmic reticulum calcium-AT-Pase (SERCA2a) is involved in the insulin-induced improvement of cardiac contractile function following I/R. Methods: Ventricular myocytes were enzymatically isolated from adult SD rats. Simulated I/R was induced by perfusing cells with chemical anoxic solution for 15 min followed by reperfusion with Tyrode's solution with or without insulin for 30 min. Myocyte shortening and intracellular calcium transients were assessed and underlying mechanisms were investigated. Results: Reperfusion with insulin (10-7 mol/L) significantly improved the recovery of contractile function (n=15-20 myocytes from 6-8 hearts, P<0.05), and increased calcium transients, as evidenced by the increased calcium (Ca2+) fluorescence ratio, shortened time to peak Ca2+ and time to 50% diastolic Ca2+, compared with those in cells reperfused with vehicle (P<0.05). In addition, Akt phosphorylation and SERCA2a activity were both increased in insulin-treated I/R cardiomyocytes, which were markedly inhibited by pretreatment of cells with a specific Akt inhibitor. Moreover, inhibition of Akt activity abolished insulin-induced positive contractile and calcium transients responses in I/R cardiomyocytes. Conclusion: These data demonstrated for the first time that insulin improves the recovery of contractile function in simulated I/R cardiomyocytes in an Akt-dependent and SERCA2a-mediated fashion.

  18. Light Chain Amyloid Fibrils Cause Metabolic Dysfunction in Human Cardiomyocytes.

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    Helen P McWilliams-Koeppen

    Full Text Available Light chain (AL amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(PH-dependent oxidoreductase, without causing significant cell death. The presence of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. These data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils.

  19. Low Molecular Weight Fucoidan Alleviates Cardiac Dysfunction in Diabetic Goto-Kakizaki Rats by Reducing Oxidative Stress and Cardiomyocyte Apoptosis

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    Xinfeng Yu

    2014-01-01

    Full Text Available Diabetic cardiomyopathy (DCM is characterized by cardiac dysfunction and cardiomyocyte apoptosis. Oxidative stress is suggested to be the major contributor to the development of DCM. This study was intended to evaluate the protective effect of low molecular weight fucoidan (LMWF against cardiac dysfunction in diabetic rats. Type 2 diabetic goto-kakizaki rats were untreated or treated with LMWF (50 and 100 mg/kg/day for three months. The establishment of DCM model and the effects of LMWF on cardiac function were evaluated by echocardiography and isolated heart perfusion. Ventricle staining with H-E or Sirius Red was performed to investigate the structural changes in myocardium. Functional evaluation demonstrated that LMWF has a beneficial effect on DCM by enhancing myocardial contractility and mitigating cardiac fibrosis. Additionally, LMWF exerted significant inhibitory effects on the reactive oxygen species production and myocyte apoptosis in diabetic hearts. The depressed activity of superoxide dismutase in diabetic heart was also improved by intervention with LMWF. Moreover, LMWF robustly inhibited the enhanced expression of protein kinase C β, an important contributor to oxidative stress, in diabetic heart and high glucose-treated cardiomyocytes. In conclusion, LMWF possesses a protective effect against DCM through ameliorations of PKCβ-mediated oxidative stress and subsequent cardiomyocyte apoptosis in diabetes.

  20. Postnatal telomere dysfunction induces cardiomyocyte cell-cycle arrest through p21 activation.

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    Aix, Esther; Gutiérrez-Gutiérrez, Óscar; Sánchez-Ferrer, Carlota; Aguado, Tania; Flores, Ignacio

    2016-06-01

    The molecular mechanisms that drive mammalian cardiomyocytes out of the cell cycle soon after birth remain largely unknown. Here, we identify telomere dysfunction as a critical physiological signal for cardiomyocyte cell-cycle arrest. We show that telomerase activity and cardiomyocyte telomere length decrease sharply in wild-type mouse hearts after birth, resulting in cardiomyocytes with dysfunctional telomeres and anaphase bridges and positive for the cell-cycle arrest protein p21. We further show that premature telomere dysfunction pushes cardiomyocytes out of the cell cycle. Cardiomyocytes from telomerase-deficient mice with dysfunctional telomeres (G3 Terc(-/-)) show precocious development of anaphase-bridge formation, p21 up-regulation, and binucleation. In line with these findings, the cardiomyocyte proliferative response after cardiac injury was lost in G3 Terc(-/-) newborns but rescued in G3 Terc(-/-)/p21(-/-) mice. These results reveal telomere dysfunction as a crucial signal for cardiomyocyte cell-cycle arrest after birth and suggest interventions to augment the regeneration capacity of mammalian hearts. PMID:27241915

  1. Pentamidine rescues contractility and rhythmicity in a Drosophila model of myotonic dystrophy heart dysfunction

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    Mouli Chakraborty

    2015-12-01

    Full Text Available Up to 80% of individuals with myotonic dystrophy type 1 (DM1 will develop cardiac abnormalities at some point during the progression of their disease, the most common of which is heart blockage of varying degrees. Such blockage is characterized by conduction defects and supraventricular and ventricular tachycardia, and carries a high risk of sudden cardiac death. Despite its importance, very few animal model studies have focused on the heart dysfunction in DM1. Here, we describe the characterization of the heart phenotype in a Drosophila model expressing pure expanded CUG repeats under the control of the cardiomyocyte-specific driver GMH5-Gal4. Morphologically, expression of 250 CUG repeats caused abnormalities in the parallel alignment of the spiral myofibrils in dissected fly hearts, as revealed by phalloidin staining. Moreover, combined immunofluorescence and in situ hybridization of Muscleblind and CUG repeats, respectively, confirmed detectable ribonuclear foci and Muscleblind sequestration, characteristic features of DM1, exclusively in flies expressing the expanded CTG repeats. Similarly to what has been reported in humans with DM1, heart-specific expression of toxic RNA resulted in reduced survival, increased arrhythmia, altered diastolic and systolic function, reduced heart tube diameters and reduced contractility in the model flies. As a proof of concept that the fly heart model can be used for in vivo testing of promising therapeutic compounds, we fed flies with pentamidine, a compound previously described to improve DM1 phenotypes. Pentamidine not only released Muscleblind from the CUG RNA repeats and reduced ribonuclear formation in the Drosophila heart, but also rescued heart arrhythmicity and contractility, and improved fly survival in animals expressing 250 CUG repeats.

  2. Pentamidine rescues contractility and rhythmicity in a Drosophila model of myotonic dystrophy heart dysfunction

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    Chakraborty, Mouli; Selma-Soriano, Estela; Magny, Emile; Couso, Juan Pablo; Pérez-Alonso, Manuel; Charlet-Berguerand, Nicolas; Artero, Ruben; Llamusi, Beatriz

    2015-01-01

    ABSTRACT Up to 80% of individuals with myotonic dystrophy type 1 (DM1) will develop cardiac abnormalities at some point during the progression of their disease, the most common of which is heart blockage of varying degrees. Such blockage is characterized by conduction defects and supraventricular and ventricular tachycardia, and carries a high risk of sudden cardiac death. Despite its importance, very few animal model studies have focused on the heart dysfunction in DM1. Here, we describe the characterization of the heart phenotype in a Drosophila model expressing pure expanded CUG repeats under the control of the cardiomyocyte-specific driver GMH5-Gal4. Morphologically, expression of 250 CUG repeats caused abnormalities in the parallel alignment of the spiral myofibrils in dissected fly hearts, as revealed by phalloidin staining. Moreover, combined immunofluorescence and in situ hybridization of Muscleblind and CUG repeats, respectively, confirmed detectable ribonuclear foci and Muscleblind sequestration, characteristic features of DM1, exclusively in flies expressing the expanded CTG repeats. Similarly to what has been reported in humans with DM1, heart-specific expression of toxic RNA resulted in reduced survival, increased arrhythmia, altered diastolic and systolic function, reduced heart tube diameters and reduced contractility in the model flies. As a proof of concept that the fly heart model can be used for in vivo testing of promising therapeutic compounds, we fed flies with pentamidine, a compound previously described to improve DM1 phenotypes. Pentamidine not only released Muscleblind from the CUG RNA repeats and reduced ribonuclear formation in the Drosophila heart, but also rescued heart arrhythmicity and contractility, and improved fly survival in animals expressing 250 CUG repeats. PMID:26515653

  3. Pentamidine rescues contractility and rhythmicity in a Drosophila model of myotonic dystrophy heart dysfunction.

    Science.gov (United States)

    Chakraborty, Mouli; Selma-Soriano, Estela; Magny, Emile; Couso, Juan Pablo; Pérez-Alonso, Manuel; Charlet-Berguerand, Nicolas; Artero, Ruben; Llamusi, Beatriz

    2015-12-01

    Up to 80% of individuals with myotonic dystrophy type 1 (DM1) will develop cardiac abnormalities at some point during the progression of their disease, the most common of which is heart blockage of varying degrees. Such blockage is characterized by conduction defects and supraventricular and ventricular tachycardia, and carries a high risk of sudden cardiac death. Despite its importance, very few animal model studies have focused on the heart dysfunction in DM1. Here, we describe the characterization of the heart phenotype in a Drosophila model expressing pure expanded CUG repeats under the control of the cardiomyocyte-specific driver GMH5-Gal4. Morphologically, expression of 250 CUG repeats caused abnormalities in the parallel alignment of the spiral myofibrils in dissected fly hearts, as revealed by phalloidin staining. Moreover, combined immunofluorescence and in situ hybridization of Muscleblind and CUG repeats, respectively, confirmed detectable ribonuclear foci and Muscleblind sequestration, characteristic features of DM1, exclusively in flies expressing the expanded CTG repeats. Similarly to what has been reported in humans with DM1, heart-specific expression of toxic RNA resulted in reduced survival, increased arrhythmia, altered diastolic and systolic function, reduced heart tube diameters and reduced contractility in the model flies. As a proof of concept that the fly heart model can be used for in vivo testing of promising therapeutic compounds, we fed flies with pentamidine, a compound previously described to improve DM1 phenotypes. Pentamidine not only released Muscleblind from the CUG RNA repeats and reduced ribonuclear formation in the Drosophila heart, but also rescued heart arrhythmicity and contractility, and improved fly survival in animals expressing 250 CUG repeats.

  4. Role of Oxidative Stress in Thyroid Hormone-Induced Cardiomyocyte Hypertrophy and Associated Cardiac Dysfunction: An Undisclosed Story

    Directory of Open Access Journals (Sweden)

    Mohammad T. Elnakish

    2015-01-01

    Full Text Available Cardiac hypertrophy is the most documented cardiomyopathy following hyperthyroidism in experimental animals. Thyroid hormone-induced cardiac hypertrophy is described as a relative ventricular hypertrophy that encompasses the whole heart and is linked with contractile abnormalities in both right and left ventricles. The increase in oxidative stress that takes place in experimental hyperthyroidism proposes that reactive oxygen species are key players in the cardiomyopathy frequently reported in this endocrine disorder. The goal of this review is to shed light on the effects of thyroid hormones on the development of oxidative stress in the heart along with the subsequent cellular and molecular changes. In particular, we will review the role of thyroid hormone-induced oxidative stress in the development of cardiomyocyte hypertrophy and associated cardiac dysfunction, as well as the potential effectiveness of antioxidant treatments in attenuating these hyperthyroidism-induced abnormalities in experimental animal models.

  5. Mouse embryonic stem cells irradiated with γ-rays differentiate into cardiomyocytes but with altered contractile properties.

    Science.gov (United States)

    Rebuzzini, Paola; Fassina, Lorenzo; Mulas, Francesca; Bellazzi, Riccardo; Redi, Carlo Alberto; Di Liberto, Riccardo; Magenes, Giovanni; Adjaye, James; Zuccotti, Maurizio; Garagna, Silvia

    2013-08-30

    Embryonic stem cells (ESCs) for their derivation from the inner cell mass of a blastocyst represent a valuable in vitro model to investigate the effects of ionizing radiation on early embryonic cellular response. Following irradiation, both human and mouse ESCs (mESCs) maintain their pluripotent status and the capacity to differentiate into embryoid bodies and to form teratomas. Although informative of the maintenance of a pluripotent status, these studies never investigated the capability of irradiated ESCs to form specific differentiated phenotypes. Here, for the first time, 5Gy-irradiated mESCs were differentiated into cardiomyocytes, thus allowing the analysis of the long-term effects of ionizing radiations on the differentiation potential of a pluripotent stem cell population. On treated mESCs, 96h after irradiation, a genome-wide expression analysis was first performed in order to determine whether the treatment influenced gene expression of the surviving mESCs. Microarrays analysis showed that only 186 genes were differentially expressed in treated mESCs compared to control cells; a quarter of these genes were involved in cellular differentiation, with three main gene networks emerging, including cardiogenesis. Based on these results, we differentiated irradiated mESCs into cardiomyocytes. On day 5, 8 and 12 of differentiation, treated cells showed a significant alteration (qRT-PCR) of the expression of marker genes (Gata-4, Nkx-2.5, Tnnc1 and Alpk3) when compared to control cells. At day 15 of differentiation, although the organization of sarcomeric α-actinin and troponin T proteins appeared similar in cardiomyocytes differentiated from either mock or treated cells, the video evaluation of the kinematics and dynamics of the beating cardiac syncytium evidenced altered contractile properties of cardiomyocytes derived from irradiated mESCs. This alteration correlated with significant reduction of Connexin 43 foci. Our results indicate that mESCs populations

  6. Troglitazone stimulates {beta}-arrestin-dependent cardiomyocyte contractility via the angiotensin II type 1{sub A} receptor

    Energy Technology Data Exchange (ETDEWEB)

    Tilley, Douglas G., E-mail: douglas.tilley@jefferson.edu [Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University (United States); Center for Translational Medicine, Thomas Jefferson University (United States); Nguyen, Anny D. [Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University (United States); Rockman, Howard A. [Department of Medicine, Duke University Medical Center (United States); Department of Cell Biology, Duke University Medical Center (United States); Department of Molecular Genetics and Microbiology, Duke University Medical Center (United States)

    2010-06-11

    Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) agonists are commonly used to treat cardiovascular diseases, and are reported to have several effects on cardiovascular function that may be due to PPAR{gamma}-independent signaling events. Select angiotensin receptor blockers (ARBs) interact with and modulate PPAR{gamma} activity, thus we hypothesized that a PPAR{gamma} agonist may exert physiologic effects via the angiotensin II type 1{sub A} receptor (AT1{sub A}R). In AT1{sub A}R-overexpressing HEK 293 cells, both angiotensin II (Ang II) and the PPAR{gamma} agonist troglitazone (Trog) enhanced AT1{sub A}R internalization and recruitment of endogenous {beta}-arrestin1/2 ({beta}arr1/2) to the AT1{sub A}R. A fluorescence assay to measure diacylglycerol (DAG) accumulation showed that although Ang II induced AT1{sub A}R-G{sub q} protein-mediated DAG accumulation, Trog had no impact on DAG generation. Trog-mediated recruitment of {beta}arr1/2 was selective to AT1{sub A}R as the response was prevented by an ARB- and Trog-mediated {beta}arr1/2 recruitment to {beta}1-adrenergic receptor ({beta}1AR) was not observed. In isolated mouse cardiomyocytes, Trog increased both % and rate of cell shortening to a similar extent as Ang II, effects which were blocked with an ARB. Additionally, these effects were found to be {beta}arr2-dependent, as cardiomyocytes isolated from {beta}arr2-KO mice showed blunted contractile responses to Trog. These findings show for the first time that the PPAR{gamma} agonist Trog acts at the AT1{sub A}R to simultaneously block G{sub q} protein activation and induce the recruitment of {beta}arr1/2, which leads to an increase in cardiomyocyte contractility.

  7. Contractile Defect Caused by Mutation in MYBPC3 Revealed under Conditions Optimized for Human PSC-Cardiomyocyte Function.

    Science.gov (United States)

    Birket, Matthew J; Ribeiro, Marcelo C; Kosmidis, Georgios; Ward, Dorien; Leitoguinho, Ana Rita; van de Pol, Vera; Dambrot, Cheryl; Devalla, Harsha D; Davis, Richard P; Mastroberardino, Pier G; Atsma, Douwe E; Passier, Robert; Mummery, Christine L

    2015-10-27

    Maximizing baseline function of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is essential for their effective application in models of cardiac toxicity and disease. Here, we aimed to identify factors that would promote an adequate level of function to permit robust single-cell contractility measurements in a human induced pluripotent stem cell (hiPSC) model of hypertrophic cardiomyopathy (HCM). A simple screen revealed the collaborative effects of thyroid hormone, IGF-1 and the glucocorticoid analog dexamethasone on the electrophysiology, bioenergetics, and contractile force generation of hPSC-CMs. In this optimized condition, hiPSC-CMs with mutations in MYBPC3, a gene encoding myosin-binding protein C, which, when mutated, causes HCM, showed significantly lower contractile force generation than controls. This was recapitulated by direct knockdown of MYBPC3 in control hPSC-CMs, supporting a mechanism of haploinsufficiency. Modeling this disease in vitro using human cells is an important step toward identifying therapeutic interventions for HCM.

  8. Contractile Defect Caused by Mutation in MYBPC3 Revealed under Conditions Optimized for Human PSC-Cardiomyocyte Function

    Directory of Open Access Journals (Sweden)

    Matthew J. Birket

    2015-10-01

    Full Text Available Maximizing baseline function of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs is essential for their effective application in models of cardiac toxicity and disease. Here, we aimed to identify factors that would promote an adequate level of function to permit robust single-cell contractility measurements in a human induced pluripotent stem cell (hiPSC model of hypertrophic cardiomyopathy (HCM. A simple screen revealed the collaborative effects of thyroid hormone, IGF-1 and the glucocorticoid analog dexamethasone on the electrophysiology, bioenergetics, and contractile force generation of hPSC-CMs. In this optimized condition, hiPSC-CMs with mutations in MYBPC3, a gene encoding myosin-binding protein C, which, when mutated, causes HCM, showed significantly lower contractile force generation than controls. This was recapitulated by direct knockdown of MYBPC3 in control hPSC-CMs, supporting a mechanism of haploinsufficiency. Modeling this disease in vitro using human cells is an important step toward identifying therapeutic interventions for HCM.

  9. Cardiac-Specific Knockout of ETA Receptor Mitigates Paraquat-Induced Cardiac Contractile Dysfunction.

    Science.gov (United States)

    Wang, Jiaxing; Lu, Songhe; Zheng, Qijun; Hu, Nan; Yu, Wenjun; Li, Na; Liu, Min; Gao, Beilei; Zhang, Guoyong; Zhang, Yingmei; Wang, Haichang

    2016-07-01

    Paraquat (1,1'-dim ethyl-4-4'-bipyridinium dichloride), a highly toxic quaternary ammonium herbicide widely used in agriculture, exerts potent toxic prooxidant effects resulting in multi-organ failure including the lung and heart although the underlying mechanism remains elusive. Recent evidence suggests possible involvement of endothelin system in paraquat-induced acute lung injury. This study was designed to examine the role of endothelin receptor A (ETA) in paraquat-induced cardiac contractile and mitochondrial injury. Wild-type (WT) and cardiac-specific ETA receptor knockout mice were challenged to paraquat (45 mg/kg, i.p.) for 48 h prior to the assessment of echocardiographic, cardiomyocyte contractile and intracellular Ca(2+) properties, as well as apoptosis and mitochondrial damage. Levels of the mitochondrial proteins for biogenesis and oxidative phosphorylation including UCP2, HSP90 and PGC1α were evaluated. Our results revealed that paraquat elicited cardiac enlargement, mechanical anomalies including compromised echocardiographic parameters (elevated left ventricular end-systolic and end-diastolic diameters as well as reduced factional shortening), suppressed cardiomyocyte contractile function, intracellular Ca(2+) handling, overt apoptosis and mitochondrial damage. ETA receptor knockout itself failed to affect myocardial function, apoptosis, mitochondrial integrity and mitochondrial protein expression. However, ETA receptor knockout ablated or significantly attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) defect, apoptosis and mitochondrial damage. Taken together, these findings revealed that endothelin system in particular the ETA receptor may be involved in paraquat-induced toxic myocardial contractile anomalies possibly related to apoptosis and mitochondrial damage. PMID:26089164

  10. Chronic Contractile Dysfunction without Hypertrophy Does Not Provoke a Compensatory Transcriptional Response in Mouse Hearts.

    Directory of Open Access Journals (Sweden)

    Scot J Matkovich

    Full Text Available Diseased myocardium from humans and experimental animal models shows heightened expression and activity of a specific subtype of phospholipase C (PLC, the splice variant PLCβ1b. Previous studies from our group showed that increasing PLCβ1b expression in adult mouse hearts by viral transduction was sufficient to cause sustained contractile dysfunction of rapid onset, which was maintained indefinitely in the absence of other pathological changes in the myocardium. We hypothesized that impaired contractility alone would be sufficient to induce a compensatory transcriptional response. Unbiased, comprehensive mRNA-sequencing was performed on 6 biological replicates of rAAV6-treated blank, PLCβ1b and PLCβ1a (closely related but inactive splice variant hearts 8 weeks after injection, when reduced contractility was manifest in PLCβ1b hearts without evidence of induced hypertrophy. Expression of PLCβ1b resulted in expression changes in only 9 genes at FDR<0.1 when compared with control and these genes appeared unrelated to contractility. Importantly, PLCβ1a caused similar mild expression changes to PLCβ1b, despite a complete lack of effect of this isoform on cardiac contractility. We conclude that contractile depression caused by PLCβ1b activation is largely independent of changes in the transcriptome, and thus that lowered contractility is not sufficient in itself to provoke measurable transcriptomic alterations. In addition, our data stress the importance of a stringent control group to filter out transcriptional changes unrelated to cardiac function.

  11. Metabolites of MDMA induce oxidative stress and contractile dysfunction in adult rat left ventricular myocytes

    OpenAIRE

    Shenouda, Sylvia K.; Varner, Kurt J.; Carvalho, Felix; Lucchesi, Pamela A.

    2009-01-01

    Repeated administration of MDMA (ecstasy) produces eccentric left ventricular (LV) dilation and diastolic dysfunction. While the mechanism(s) underlying this toxicity are unknown; oxidative stress plays an important role. MDMA is metabolized into redox cycling metabolites that produce superoxide. In this study, we demonstrated that metabolites of MDMA induce oxidative stress and contractile dysfunction in adult rat left ventricular myocytes. Metabolites of MDMA used in this study included: al...

  12. Contractile dysfunction in muscle may underlie androgen-dependent motor dysfunction in spinal bulbar muscular atrophy.

    Science.gov (United States)

    Oki, Kentaro; Halievski, Katherine; Vicente, Laura; Xu, Youfen; Zeolla, Donald; Poort, Jessica; Katsuno, Masahisa; Adachi, Hiroaki; Sobue, Gen; Wiseman, Robert W; Breedlove, S Marc; Jordan, Cynthia L

    2015-04-01

    Spinal and bulbar muscular atrophy (SBMA) is characterized by progressive muscle weakness linked to a polyglutamine expansion in the androgen receptor (AR). Current evidence indicates that mutant AR causes SBMA by acting in muscle to perturb its function. However, information about how muscle function is impaired is scant. One fundamental question is whether the intrinsic strength of muscles, an attribute of muscle independent of its mass, is affected. In the current study, we assess the contractile properties of hindlimb muscles in vitro from chronically diseased males of three different SBMA mouse models: a transgenic (Tg) model that broadly expresses a full-length human AR with 97 CAGs (97Q), a knock-in (KI) model that expresses a humanized AR containing a CAG expansion in the first exon, and a Tg myogenic model that overexpresses wild-type AR only in skeletal muscle fibers. We found that hindlimb muscles in the two Tg models (97Q and myogenic) showed marked losses in their intrinsic strength and resistance to fatigue, but were minimally affected in KI males. However, diseased muscles of all three models showed symptoms consistent with myotonic dystrophy type 1, namely, reduced resting membrane potential and deficits in chloride channel mRNA. These data indicate that muscle dysfunction is a core feature of SBMA caused by at least some of the same pathogenic mechanisms as myotonic dystrophy. Thus mechanisms controlling muscle function per se independent of mass are prime targets for SBMA therapeutics.

  13. Chronic Contractile Dysfunction without Hypertrophy Does Not Provoke a Compensatory Transcriptional Response in Mouse Hearts.

    Science.gov (United States)

    Matkovich, Scot J; Grubb, David R; McMullen, Julie R; Woodcock, Elizabeth A

    2016-01-01

    Diseased myocardium from humans and experimental animal models shows heightened expression and activity of a specific subtype of phospholipase C (PLC), the splice variant PLCβ1b. Previous studies from our group showed that increasing PLCβ1b expression in adult mouse hearts by viral transduction was sufficient to cause sustained contractile dysfunction of rapid onset, which was maintained indefinitely in the absence of other pathological changes in the myocardium. We hypothesized that impaired contractility alone would be sufficient to induce a compensatory transcriptional response. Unbiased, comprehensive mRNA-sequencing was performed on 6 biological replicates of rAAV6-treated blank, PLCβ1b and PLCβ1a (closely related but inactive splice variant) hearts 8 weeks after injection, when reduced contractility was manifest in PLCβ1b hearts without evidence of induced hypertrophy. Expression of PLCβ1b resulted in expression changes in only 9 genes at FDRcaused similar mild expression changes to PLCβ1b, despite a complete lack of effect of this isoform on cardiac contractility. We conclude that contractile depression caused by PLCβ1b activation is largely independent of changes in the transcriptome, and thus that lowered contractility is not sufficient in itself to provoke measurable transcriptomic alterations. In addition, our data stress the importance of a stringent control group to filter out transcriptional changes unrelated to cardiac function. PMID:27359099

  14. Contractility and protein phosphorylation in cardiomyocytes: effects of isoproterenol and AR-L57.

    Science.gov (United States)

    Hayes, J S; Bowling, N; Boder, G B

    1984-08-01

    The cardiotonic drugs AR-L57 [2-(2,4-dimethoxyphenyl)-1H-imidazo(4,5b)-pyridine] and isoproterenol stimulated contractility in cultured heart cells in concentration-dependent manners; only the effects of isoproterenol were blocked by propranolol. Isoproterenol, but not AR-L57, enhanced the phosphorylation state of seven protein bands [relative molecular weights (MrS) 155,000, 96,000, 27,000, 24,000, 20,000, 16,000, 12,000] and resulted in the dephosphorylation of one protein band (Mr 21,000). Also, only isoproterenol increased the activation states of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase and glycogen phosphorylase. The eight protein bands resolved by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and detected by autoradiography were altered by isoproterenol in time- and concentration-dependent manners. The 24,000-Mr protein substrate phosphorylated in response to isoproterenol was converted to a 12,000-Mr species by heating in the presence of SDS prior to electrophoresis, suggesting that the two substrates were in fact identical proteins. A comparison of the 2-min responses to varying concentrations of isoproterenol resulted in excellent correlations between the phosphorylation states of individual protein bands and contractility. This was true even for the 21,000-Mr species that was dephosphorylated. However, only the 27,000-, 24-12,000-, and 16,000-Mr substrates were phosphorylated rapidly enough to be associated with the onset of the inotropic response. Cultured myocytes are an important feature of these studies as they are 84% pure ventricular cells that remain 100% viable throughout an experiment. Because this system is suitable for biochemical measurements and the effects of agents on heart cell contractility can be determined, it is possible to correlate changes in biochemical parameters with alterations in physiological state.

  15. Changes of mitochondria in the contractile cardiomyocytes during postnatal rat ontogenesis

    OpenAIRE

    Kozlov S.V.; Mayevsky A.E.; Mіshalov V.D.; Sulayeva O.N.

    2014-01-01

    Background. CVDs are the number 1 cause of death globally: more people die annually from CVDs than from any other cause. An estimated 17.5 million people died from CVDs in 2012, representing 31% of all global deaths. Of these deaths, an estimated 7.4 million were due to coronary heart disease and 6.7 million were due to stroke. Over three quarters of CVD deaths take place in low- and middle-income countries. Objective. Ultrastructural analysis of mitochondria in the rat contractile cardiomyoc...

  16. Lymphatic filariasis: Perspectives on lymphatic remodeling and contractile dysfunction in filarial disease pathogenesis

    OpenAIRE

    Chakraborty, Sanjukta; Gurusamy, Manokaran; Zawieja, David C.; Muthuchamy, Mariappan

    2013-01-01

    Lymphatic filariasis, one of the most debilitating diseases associated with the lymphatic system, affects over a hundred million people worldwide and manifests itself in a variety of severe clinical pathologies. The filarial parasites specifically target the lymphatics and impair lymph flow, which is critical for the normal functions of the lymphatic system in maintenance of body fluid balance and physiological interstitial fluid transport. The resultant contractile dysfunction of the lymphat...

  17. Effects of neutral sulfate berberine on LPS-induced cardiomyocyte TNF-αsecretion, abnormal calcium cycling, and cardiac dysfunction in rats

    Institute of Scientific and Technical Information of China (English)

    Jing YANG; Hua-dong WANG; Da-xiang LU; Yan-ping WANG; Ren-bin QI; Jing LI; Fei LI; Chu-jie LI

    2006-01-01

    Aim: To evaluate the effect of neutral sulfate berberine on cardiac function, tumornecrosis factor α (TNF-α) release, and intracellular calcium concentration ([Ca2+]i)in cardiomyocytes exposed to lipopolysaccharide (LPS). Methods: Primary cultured rat cardiomyocytes were prepared from ventricles of 3-4-day old SpragueDawley rats. TNF-α concentrations in cell-conditioned media were measured by using a Quantikine enzyme-linked immunosorbent assay kit, and cardiomyocyte [Ca2+]i was measured by using Fura-2/AM. The isolated rat hearts were perfused in the Langendorff mode. Results: LPS at doses of 1, 5, 10, and 20 μg/mL markedly stimulated TNF-α secretion from cardiomyocytes, and neutral sulfate berberine inhibited LPS-induced TNF-α production. Intracellular calcium concentration was significantly decreased after LPS stimulation for 1 h, and increased 2 h after LPS treatment. Pretreatment with neutral sulfate berberine reversed the LPS-induced [Ca2+]i alterations, although neutral sulfate berberine did not inhibit a rapid increase in cardiomyocyte [Ca2+]i induced by LPS. Perfusion of isolated hearts with LPS (100 μg/mL) for 20 min resulted in significantly impaired cardiac performance at 120 min after LPS challenge: the maximal rate of left ventricular pressure rise and fall (±dp/dtmax) decreased compared with the control. In contrast, ±dp/dtmax at 120min in hearts perfused with neutral sulfate berberine (1 μmol/L) for 10 min followed by 20 min LPS (100 μg/mL) was greater than the corresponding value in the LPS group. Conclusion: Neutral sulfate berberine inhibits LPS-stimulated myocardial TNF-α production, impairs calcium cycling, and improves LPS-induced contractile dysfunction in intact heart.

  18. Protein Changes Contributing to Right Ventricular Cardiomyocyte Diastolic Dysfunction in Pulmonary Arterial Hypertension

    Science.gov (United States)

    Rain, Silvia; Bos, Denielli da Silva Goncalves; Handoko, M. Louis; Westerhof, Nico; Stienen, Ger; Ottenheijm, Coen; Goebel, Max; Dorfmüller, Peter; Guignabert, Christophe; Humbert, Marc; Bogaard, Harm‐Jan; dos Remedios, Cris; Saripalli, Chandra; Hidalgo, Carlos G.; Granzier, Henk L.; Vonk‐Noordegraaf, Anton; van der Velden, Jolanda; de Man, Frances S.

    2014-01-01

    Background Right ventricular (RV) diastolic function is impaired in patients with pulmonary arterial hypertension (PAH). Our previous study showed that elevated cardiomyocyte stiffness and myofilament Ca2+ sensitivity underlie diastolic dysfunction in PAH. This study investigates protein modifications contributing to cellular diastolic dysfunction in PAH. Methods and Results RV samples from PAH patients undergoing heart‐lung transplantation were compared to non‐failing donors (Don). Titin stiffness contribution to RV diastolic dysfunction was determined by Western‐blot analyses using antibodies to protein‐kinase‐A (PKA), Cα (PKCα) and Ca2+/calmoduling‐dependent‐kinase (CamKIIδ) titin and phospholamban (PLN) phosphorylation sites: N2B (Ser469), PEVK (Ser170 and Ser26), and PLN (Thr17), respectively. PKA and PKCα sites were significantly less phosphorylated in PAH compared with donors (P<0.0001). To test the functional relevance of PKA‐, PKCα‐, and CamKIIδ‐mediated titin phosphorylation, we measured the stiffness of single RV cardiomyocytes before and after kinase incubation. PKA significantly decreased PAH RV cardiomyocyte diastolic stiffness, PKCα further increased stiffness while CamKIIδ had no major effect. CamKIIδ activation was determined indirectly by measuring PLN Thr17phosphorylation level. No significant changes were found between the groups. Myofilament Ca2+ sensitivity is mediated by sarcomeric troponin I (cTnI) phosphorylation. We observed increased unphosphorylated cTnI in PAH compared with donors (P<0.05) and reduced PKA‐mediated cTnI phosphorylation (Ser22/23) (P<0.001). Finally, alterations in Ca2+‐handling proteins contribute to RV diastolic dysfunction due to insufficient diastolic Ca2+ clearance. PAH SERCA2a levels and PLN phosphorylation were significantly reduced compared with donors (P<0.05). Conclusions Increased titin stiffness, reduced cTnI phosphorylation, and altered levels of phosphorylation of Ca2

  19. Cardiomyocyte overexpression of miR-27b induces cardiac hypertrophy and dysfunction in mice

    Institute of Scientific and Technical Information of China (English)

    Jian Wang; Dawei Zhan; Lagabaiyila Zha; Yang Cao; Zhenhua Li; Xuan Cheng; Youyi Zhang; XiaoYang; Yao Song; Yan Zhang; Han Xiao; Qiang Sun; Ning Hou; Shuilong Guo; Youliang Wang; Kaiji Fan

    2012-01-01

    Recent studies have begun to reveal critical roles of microRNAs(miRNAs)in the pathogenesis of cardiac hypertrophy and dysfunction.In this study,we tested whether a transforming growth factor-β(TGF-β)-regulated miRNA played a pivotal role in the development of cardiac hypertrophy and heart failure(HF).We observed that miR-27b was upregulated in hearts of cardiomyocyte-specific Smad4 knockout mice,which developed cardiac hypertrophy.In vitro experiments showed that the miR-27b expression could be inhibited by TGF-β1 and that its overexpression promoted hypertrophic cell growth,while the miR-27b suppression led to inhibition of the hypertrophic cell growth caused by phenylephrine(PE)treatment.Furthermore,the analysis of transgenic mice with cardiomyocyte-specific overexpression of miR-27b revealed that miR-27b overexpression was sufficient to induce cardiac hypertrophy and dysfunction.We validated the peroxisome proliferator-activated receptor-γ(PPAR-γ)as a direct target of miR-27b in cardiomyocyte.Consistently,the miR-27b transgenic mice displayed significantly lower levels of PPAR-γ than the control mice.Furthermore,in vivo silencing of miR-27b using a specific antagomir in a pressure-overload-induced mouse model of HF increased cardiac PPAR-γ expression,attenuated cardiac hypertrophy and dysfunction.The results of our study demonstrate that TGF-β1-regulated miR-27b is involved in the regulation of cardiac hypertrophy,and validate miR-27b as an efficient therapeutic target for cardiac diseases.

  20. Integrated Analysis of Contractile Kinetics, Force Generation, and Electrical Activity in Single Human Stem Cell-Derived Cardiomyocytes

    NARCIS (Netherlands)

    Kijlstra, Jan David; Hu, Dongjian; Mittal, Nikhil; Kausel, Eduardo; van der Meer, Peter; Garakani, Arman; Domian, Ibrahim J.

    2015-01-01

    The quantitative analysis of cardiomyocyte function is essential for stem cell-based approaches for the in vitro study of human cardiac physiology and pathophysiology. We present a method to comprehensively assess the function of single human pluripotent stem cell-derived cardiomyocyte (hPSC-CMs) th

  1. Prostaglandins attenuate cardiac contractile dysfunction produced by free radical generation but not by hydrogen peroxide.

    Science.gov (United States)

    Zimmer, K M; Karmazyn, M

    1997-11-01

    The aim of this study was to examine and compare the potential influence of cyclooxygenase or lipoxygenase derived metabolites of arachidonic acid on myocardial injury produced either by a free radical generating system consisting of purine plus xanthine oxidase or that produced by hydrogen peroxide. A free radical generating system consisting of purine (2.3 mM) and xanthine oxidase (10 U/L) as well as hydrogen peroxide (75 microM) produced significant functional changes in the absence of either significant deficits in high energy phosphates or ultrastructural damage. Prostaglandin F2 alpha (30 nM) significantly attenuated both the negative inotropic effect of purine plus xanthine oxidase as well as the ability of the free radical generator to elevate diastolic pressure. An identical concentration of prostaglandin 12 (prostacyclin) significantly reduced diastolic pressure elevation only and had no effect on contractile depression. The salutary effects of the two PGs occurred in the absence of any inhibitory influence on superoxide anion generation produced by the purine and xanthine oxidase reaction. None of prostaglandins modulated the response to hydrogen peroxide. In addition, neither prostaglandin E2 nor leukotrienes exerted any effect on changes produced by either type of oxidative stress. A 5 fold elevation in the concentrations of free radical generators or hydrogen peroxide produced extensive injury as characterized by a virtual total loss in contractility, 400% elevation in diastolic pressure, ultrastructural damage and significant depletions in high energy phosphate content. None of these effects were modulated by eicosanoid treatment. Our results therefore demonstrate a selective ability of both prostaglandin F2 alpha and to a lesser extent prostacyclin, to attenuate dysfunction produced by purine plus xanthine oxidase but not hydrogen peroxide. It is possible that these eicosanoids may represent endogenous protective factors under conditions of enhanced

  2. Cardiac-specific knockout of ETA receptor mitigates low ambient temperature-induced cardiac hypertrophy and contractile dysfunction

    Institute of Scientific and Technical Information of China (English)

    Yingmei Zhang; Linlin Li; Yinan Hua; Jennifer M. Nunn; Feng Dong; Masashi Yanagisawa; Jun Ren

    2012-01-01

    Cold exposure is associated with oxidative stress and cardiac dysfunction.The endothelin (ET) system,which plays a key role in myocardial homeostasis,may participate in cold exposure-induced cardiovascular dysfunction.This study was designed to examine the role of ET-1 in cold stress-induced cardiac geometric and contractile responses.Wild-type (WT) and ETA receptor knockout (ETAKO) mice were assigned to normal or cold exposure (4℃) environment for 2 and 5 weeks prior to evaluation of cardiac geometry,contractile,and intracellular Ca2+ properties.Levels of the temperature sensor transient receptor potential vanlllold (TRPV1),mitochondrlal proteins for biogenesis and oxidative phosphorylatlon,Including UCP2,HSP90,and PGC1α were evaluated.Cold stress triggered cardiac hypertrophy,depressed myocardial contractile capacity,including fractional shortening,peak shortening,and maximal velocity of shortening/relengthening,reduced intracellular Ca2+ release,prolonged intracellular Ca2+ decay and relengthening duration,generation of ROS and superoxide,as well as apoptosls,the effects of which were blunted by ETAKO.Western blotting revealed downregulated TRPV1 and PGC1α as well as upregulated UCP2 and activation of GSK3β,GATA4,and CREB in cold-stressed WT mouse hearts,which were obliterated by ETAKO.Levels of HSP90,an essential regulator for thermotolerance,were unchanged.The TRPV1 agonist SA13353 attenuated whereas TRPV1 antagonist capsazepino mimicked cold stress- or ET-1-induced cardiac anomalies.The GSK3β Inhibitor SB216763 ablated cold stress-induced cardiac contractile (but not remodeling) changes and ET-1-induced TRPV1 downregulation.These data suggest that ETAKO protects against cold exposure-induced cardiac remodeling and dysfunction mediated through TRPV1 and mitochondrlal function.

  3. An anthelmintic drug, pyrvinium pamoate, thwarts fibrosis and ameliorates myocardial contractile dysfunction in a mouse model of myocardial infarction.

    Directory of Open Access Journals (Sweden)

    Motoaki Murakoshi

    Full Text Available Metabolic adaptation to limited supplies of oxygen and nutrients plays a pivotal role in health and disease. Heart attack results from insufficient delivery of oxygen and nutrients to the heart, where cardiomyocytes die and cardiac fibroblasts proliferate--the latter causing scar formation, which impedes regeneration and impairs contractility of the heart. We postulated that cardiac fibroblasts survive metabolic stress by adapting their intracellular metabolism to low oxygen and nutrients, and impeding this metabolic adaptation would thwart their survival and facilitate the repair of scarred heart. Herein, we show that an anthelmintic drug, Pyrvinium pamoate, which has been previously shown to compromise cancer cell survival under glucose starvation condition, also disables cardiac fibroblast survival specifically under glucose deficient condition. Furthermore, Pyrvinium pamoate reduces scar formation and improves cardiac contractility in a mouse model of myocardial infarction. As Pyrvinium pamoate is an FDA-approved drug, our results suggest a therapeutic use of this or other related drugs to repair scarred heart and possibly other organs.

  4. NOX2 amplifies acetaldehyde-mediated cardiomyocyte mitochondrial dysfunction in alcoholic cardiomyopathy

    Science.gov (United States)

    Brandt, Moritz; Garlapati, Venkata; Oelze, Matthias; Sotiriou, Efthymios; Knorr, Maike; Kröller-Schön, Swenja; Kossmann, Sabine; Schönfelder, Tanja; Morawietz, Henning; Schulz, Eberhard; Schultheiss, Heinz-Peter; Daiber, Andreas; Münzel, Thomas; Wenzel, Philip

    2016-01-01

    Alcoholic cardiomyopathy (ACM) resulting from excess alcohol consumption is an important cause of heart failure (HF). Although it is assumed that the cardiotoxicity of the ethanol (EtOH)-metabolite acetaldehyde (ACA) is central for its development and progression, the exact mechanisms remain obscure. Murine cardiomyocytes (CMs) exposed to ACA or EtOH showed increased superoxide (O2•−) levels and decreased mitochondrial polarization, both being normalized by NADPH oxidase (NOX) inhibition. C57BL/6 mice and mice deficient for the ACA-degrading enzyme mitochondrial aldehyde dehydrogenase (ALDH-2−/−) were fed a 2% EtOH diet for 5 weeks creating an ACA-overload. 2% EtOH-fed ALDH-2−/− mice exhibited a decreased cardiac function, increased heart-to-body and lung-to-body weight ratios, increased cardiac levels of the lipid peroxidation product malondialdehyde (MDA) as well as increased NOX activity and NOX2/glycoprotein 91phox (NOX2/gp91phox) subunit expression compared to 2% EtOH-fed C57BL/6 mice. Echocardiography revealed that ALDH-2−/−/gp91phox−/− mice were protected from ACA-overload-induced HF after 5 weeks of 2% EtOH-diet, demonstrating that NOX2-derived O2•− contributes to the development of ACM. Translated to human pathophysiology, we found increased gp91phox expression in endomyocardial biopsies of ACM patients. In conclusion, ACM is promoted by ACA-driven mitochondrial dysfunction and can be improved by ablation of NOX2/gp91phox. NOX2/gp91phox therefore might be a potential pharmacological target to treat ACM. PMID:27624556

  5. Oleanolic acid: a novel cardioprotective agent that blunts hyperglycemia-induced contractile dysfunction.

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    Rudo F Mapanga

    Full Text Available Diabetes constitutes a major health challenge. Since cardiovascular complications are common in diabetic patients this will further increase the overall burden of disease. Furthermore, stress-induced hyperglycemia in non-diabetic patients with acute myocardial infarction is associated with higher in-hospital mortality. Previous studies implicate oxidative stress, excessive flux through the hexosamine biosynthetic pathway (HBP and a dysfunctional ubiquitin-proteasome system (UPS as potential mediators of this process. Since oleanolic acid (OA; a clove extract possesses antioxidant properties, we hypothesized that it attenuates acute and chronic hyperglycemia-mediated pathophysiologic molecular events (oxidative stress, apoptosis, HBP, UPS and thereby improves contractile function in response to ischemia-reperfusion. We employed several experimental systems: 1 H9c2 cardiac myoblasts were exposed to 33 mM glucose for 48 hr vs. controls (5 mM glucose; and subsequently treated with two OA doses (20 and 50 µM for 6 and 24 hr, respectively; 2 Isolated rat hearts were perfused ex vivo with Krebs-Henseleit buffer containing 33 mM glucose vs. controls (11 mM glucose for 60 min, followed by 20 min global ischemia and 60 min reperfusion ± OA treatment; 3 In vivo coronary ligations were performed on streptozotocin treated rats ± OA administration during reperfusion; and 4 Effects of long-term OA treatment (2 weeks on heart function was assessed in streptozotocin-treated rats. Our data demonstrate that OA treatment blunted high glucose-induced oxidative stress and apoptosis in heart cells. OA therapy also resulted in cardioprotection, i.e. for ex vivo and in vivo rat hearts exposed to ischemia-reperfusion under hyperglycemic conditions. In parallel, we found decreased oxidative stress, apoptosis, HBP flux and proteasomal activity following ischemia-reperfusion. Long-term OA treatment also improved heart function in streptozotocin-diabetic rats. These

  6. Loss of cortactin causes endothelial barrier dysfunction via disturbed adrenomedullin secretion and actomyosin contractility.

    Science.gov (United States)

    García Ponce, Alexander; Citalán Madrid, Alí F; Vargas Robles, Hilda; Chánez Paredes, Sandra; Nava, Porfirio; Betanzos, Abigail; Zarbock, Alexander; Rottner, Klemens; Vestweber, Dietmar; Schnoor, Michael

    2016-01-01

    Changes in vascular permeability occur during inflammation and the actin cytoskeleton plays a crucial role in regulating endothelial cell contacts and permeability. We demonstrated recently that the actin-binding protein cortactin regulates vascular permeability via Rap1. However, it is unknown if the actin cytoskeleton contributes to increased vascular permeability without cortactin. As we consistently observed more actin fibres in cortactin-depleted endothelial cells, we hypothesised that cortactin depletion results in increased stress fibre contractility and endothelial barrier destabilisation. Analysing the contractile machinery, we found increased ROCK1 protein levels in cortactin-depleted endothelium. Concomitantly, myosin light chain phosphorylation was increased while cofilin, mDia and ERM were unaffected. Secretion of the barrier-stabilising hormone adrenomedullin, which activates Rap1 and counteracts actomyosin contractility, was reduced in plasma from cortactin-deficient mice and in supernatants of cortactin-depleted endothelium. Importantly, adrenomedullin administration and ROCK1 inhibition reduced actomyosin contractility and rescued the effect on permeability provoked by cortactin deficiency in vitro and in vivo. Our data suggest a new role for cortactin in controlling actomyosin contractility with consequences for endothelial barrier integrity. PMID:27357373

  7. DOBUTAMINE MAGNETIC RESONANCE IMAGING PREDICTS CONTRACTILE RESERVE OF CHRONICALLY DYSFUNCTIONAL MYOCARDIUM: COMPARISON WITH FLUORINE-18 FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective. This study sought to investigate whether low-dose dobutamine-MRI can detect residual myocardial viability in patients with chronic myocardial infarction and left ventricular dysfunction.Methods. Eleven patients with chronic myocardial infarction and left ventricular dysfunction were employed for identification of viable myocardium by cine-MRI during dobutamine infusion. All patients underwent coronary angiography and left ventriculography,18FDG-PET, MRI at rest and stress.The systolic wall thickening measured at rest and during stress was compared with the results of 18FDG- PET, respectively.Results. A significant difference of either dobutamine-induced systolic wall thickening (SWthstress) or dobutamine-induced contractile reserve (ΔSWth= SWthstress- SWthrest) was present between viable and scar regions (1.0±0.3 versus -0.3 ±0.1, P<0.01; 1.0±0.3 versus -0.2±0.2, P<0.01).

  8. Mechanism underlying the reversal of contractility dysfunction in experimental colitis by cyclooxygenase-2 inhibition.

    Science.gov (United States)

    Khan, I; Oriowo, M A

    2006-03-01

    Inflammatory bowel diseases are associated with reduced colonic contractility and induction of cyclooxygenase-2. In this study a possible role of cyclooxygenase-2 in and the underlying mechanism of the reduced contractility were investigated in experimental colitis. The effects of meloxicam, a cyclooxygenase-2 selective inhibitor were examined on colonic contractility and MAP kinase p38 and ERK(1/2) expression. Colitis was induced in Sprague-Dawley male rats by intra-colonic instillation of trinitrobenzenesulphonic acid (TNBS; 40 mg/rat in 50 ethanol). The animals were divided into three groups. Group 1 (n=9) received meloxicam (3 mg/kg-day) gavage 1 h before and 1 day (Group 2) after induction of colitis. Group 3 (n=9) received phosphate buffered saline (PBS) in a similar manner and served as colitic control. The non colitic control animals received meloxicam in a similar manner. The animals were sacrificed after 5 days of treatment, colon was cleaned with PBS and colonic smooth muscle was obtained which was used in this study. Meloxicam treatment given 1 h before or 1 day after administration of colitis restored the reduced colonic contractility without affecting the sensitivity to carbachol. The levels of colonic smooth muscle IL-1beta mRNA, PGE(2), ERK(1/2), p38, malondialdehyde, myeloperoxidase activity and colonic mass were increased, whereas the body weight was decreased due to TNBS. The changes except colonic muscle mass and p38 expression were reversed by meloxicam treatment. These findings indicate that restoration of reduced colonic contractility by meloxicam is mediated by ERK(1/2), and that ERK(1/2) may serve as an important anti inflammatory target for treatment of colitis. PMID:16835710

  9. Adiponectin alleviates contractile dysfunction of genioglossus in rats exposed to chronic intermittent hypoxia

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-jing; LU Gan; DING Ning; HUANG Han-peng; DING Wen-xiao; ZHANG Xi-long

    2013-01-01

    Background Genioglossal dysfuntion takes an important role in pathogenesis of obstructive sleep apnea hypopnea syndrome (OSAHS) in which chronic intermittent hypoxia (CIH) is the major pathological origin.Recent studies have suggested genioglossal injury induced by CIH might be improved by adiponectin.The aim of this study was to investigate the effects of adiponectin on genioglossus contractile properties in rats exposed to CIH.Methods Thirty-nine healthy male Wistar rats were randomly divided into three groups:normal control (NC),CIH and adiponectin supplement (CIH+Ad) with 13 rats in each.Rats in NC were kept breathing normal air,while rats in CIH and CIH+Ad experienced the same CIH environment eight hours per day for 35 successive days.Rats in CIH+Ad were given intravenous adiponectin of 10 μg twice a week for 30 successive days.Rats in the NC and CIH were injected with normal saline as a control.After 35 days' CIH exposure,the levels of serum adiponectin and genioglossus contractile properties were compared.Results Serum adiponectin level was significantly lower in CIH than in NC (1210 ng/ml vs.2236 ng/ml).Serum adiponectin level in CIH+Ad (1844 ng/ml) was significantly higher than CIH but lower than NC.Twitch tension,time to peak tension,half relaxation time and tetanic tension were significantly lower in CIH than NC and improved in CIH+Ad.All mean tetanic fatigue indices decreased more rapidly in the first 20 seconds than during the subsequent 100 seconds.Tetanic fatigue indices in NC and CIH+Ad were significantly higher compared to CIH.Conclusions CIH could lead to hypoadiponectinaemia,impaired genioglossus contractile properties and decreased fatigue resistance in rats.Such changes could be partially offset by supplementation of adiponectin.

  10. Group B streptococcal beta-hemolysin/cytolysin directly impairs cardiomyocyte viability and function.

    Directory of Open Access Journals (Sweden)

    Mary E Hensler

    Full Text Available BACKGROUND: Group B Streptococcus (GBS is a leading cause of neonatal sepsis where myocardial dysfunction is an important contributor to poor outcome. Here we study the effects of the GBS pore-forming beta-hemolysin/cytolysin (Bh/c exotoxin on cardiomyocyte viability, contractility, and calcium transients. METHODOLOGY/PRINCIPAL FINDINGS: HL-1 cardiomyocytes exposed to intact wild-type (WT or isogenic Deltabeta h/c mutant GBS, or to cell-free extracts from either strain, were assessed for viability by trypan blue exclusion and for apoptosis by TUNEL staining. Functionality of exposed cardiomyocytes was analyzed by visual quantitation of the rate and extent of contractility. Mitochondrial membrane polarization was measured in TMRE-loaded cells exposed to GBS beta h/c. Effects of GBS beta h/c on calcium transients were studied in fura-2AM-loaded primary rat ventricular cardiomyocytes. Exposure of HL-1 cardiomyocytes to either WT GBS or beta h/c extracts significantly reduced both rate and extent of contractility and later induced necrotic and apoptotic cell death. No effects on cardiomyocyte viability or function were observed after treatment with Deltabeta h/c mutant bacteria or extracts. The beta h/c toxin was associated with complete and rapid loss of detectable calcium transients in primary neonatal rat ventricular cardiomyocytes and induced a loss of mitochondrial membrane polarization. These effects on viability and function were abrogated by the beta h/c inhibitor, dipalmitoyl phosphatidylcholine (DPPC. CONCLUSIONS/SIGNIFICANCE: Our data show a rapid loss of cardiomyocyte viability and function induced by GBS beta h/c, and these deleterious effects are inhibited by DPPC, a normal constituent of human pulmonary surfactant.. These findings have clinical implications for the cardiac dysfunction observed in neonatal GBS infections.

  11. Autophagy protects cardiomyocytes from the myocardial ischaemia-reperfusion injury through the clearance of CLP36

    Science.gov (United States)

    Li, Shiguo; Liu, Chao; Gu, Lei; Wang, Lina; Shang, Yongliang; Liu, Qiong; Wan, Junyi; Shi, Jian; Wang, Fang; Xu, Zhiliang; Ji, Guangju

    2016-01-01

    Cardiovascular disease (CVD) is the leading cause of the death worldwide. An increasing number of studies have found that autophagy is involved in the progression or prevention of CVD. However, the precise mechanism of autophagy in CVD, especially the myocardial ischaemia-reperfusion injury (MI/R injury), is unclear and controversial. Here, we show that the cardiomyocyte-specific disruption of autophagy by conditional knockout of Atg7 leads to severe contractile dysfunction, myofibrillar disarray and vacuolar cardiomyocytes. A negative cytoskeleton organization regulator, CLP36, was found to be accumulated in Atg7-deficient cardiomyocytes. The cardiomyocyte-specific knockout of Atg7 aggravates the MI/R injury with cardiac hypertrophy, contractile dysfunction, myofibrillar disarray and severe cardiac fibrosis, most probably due to CLP36 accumulation in cardiomyocytes. Altogether, this work reveals autophagy may protect cardiomyocytes from the MI/R injury through the clearance of CLP36, and these findings define a novel relationship between autophagy and the regulation of stress fibre in heart. PMID:27512143

  12. PTRF/Cavin-1 Deficiency Causes Cardiac Dysfunction Accompanied by Cardiomyocyte Hypertrophy and Cardiac Fibrosis

    Science.gov (United States)

    Ogata, Takehiro; Kasahara, Takeru; Nakanishi, Naohiko; Miyagawa, Kotaro; Naito, Daisuke; Hamaoka, Tetsuro; Nishi, Masahiro; Matoba, Satoaki; Ueyama, Tomomi

    2016-01-01

    Mutations in the PTRF/Cavin-1 gene cause congenital generalized lipodystrophy type 4 (CGL4) associated with myopathy. Additionally, long-QT syndrome and fatal cardiac arrhythmia are observed in patients with CGL4 who have homozygous PTRF/Cavin-1 mutations. PTRF/Cavin-1 deficiency shows reductions of caveolae and caveolin-3 (Cav3) protein expression in skeletal muscle, and Cav3 deficiency in the heart causes cardiac hypertrophy with loss of caveolae. However, it remains unknown how loss of PTRF/Cavin-1 affects cardiac morphology and function. Here, we present a characterization of the hearts of PTRF/Cavin-1-null (PTRF−/−) mice. Electron microscopy revealed the reduction of caveolae in cardiomyocytes of PTRF−/− mice. PTRF−/− mice at 16 weeks of age developed a progressive cardiomyopathic phenotype with wall thickening of left ventricles and reduced fractional shortening evaluated by echocardiography. Electrocardiography revealed that PTRF−/− mice at 24 weeks of age had low voltages and wide QRS complexes in limb leads. Histological analysis showed cardiomyocyte hypertrophy accompanied by progressive interstitial/perivascular fibrosis. Hypertrophy-related fetal gene expression was also induced in PTRF−/− hearts. Western blotting analysis and quantitative RT-PCR revealed that Cav3 expression was suppressed in PTRF−/− hearts compared with that in wild-type (WT) ones. ERK1/2 was activated in PTRF−/− hearts compared with that in WT ones. These results suggest that loss of PTRF/Cavin-1 protein expression is sufficient to induce a molecular program leading to cardiomyocyte hypertrophy and cardiomyopathy, which is partly attributable to Cav3 reduction in the heart. PMID:27612189

  13. Roles of calcium and IP3 in impaired colon contractility of rats following multiple organ dysfunction syndrome

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    C. Zheyu

    2007-10-01

    Full Text Available The purpose of the present study was to explore changes in rat colon motility, and determine the roles of calcium and inositol (1,4,5-triphosphate (IP3 in colon dysmotility induced by multiple organ dysfunction syndrome (MODS caused by bacteria peritonitis. The number of stools, the contractility of the muscle strips and the length of smooth muscle cells (SMC in the colon, the concentration of calcium and IP3 in SMC, and serum nitric oxide were measured. Number of stools, fecal weight, IP3 concentration in SMC and serum nitric oxide concentration were 0.77 ± 0.52 pellets, 2.51 ± 0.39 g, 4.14 ± 2.07 pmol/tube, and 113.95 ± 37.89 µmol/L, respectively, for the MODS group (N = 11 vs 1.54 ± 0.64 pellets, 4.32 ± 0.57 g, 8.19 ± 3.11 pmol/tube, and 37.42 ± 19.56 µmol/L for the control group (N = 20; P < 0.05. After treatment with 0.1 mM acetylcholine and 0.1 M potassium chloride, the maximum contraction stress of smooth muscle strips, the length of SMC and the changes of calcium concentration were 593 ± 81 and 458 ± 69 g/cm³, 48.1 ± 11.8 and 69.2 ± 15.7 µM, 250 ± 70 and 167 ± 48%, respectively, for the control group vs 321 ± 53 and 284 ± 56 g/cm³, 65.1 ± 18.5 and 87.2 ± 23.7 µM, 127 ± 35 and 112 ± 35% for the MODS group (P < 0.05. Thus, colon contractility was decreased in MODS, a result possibly related to reduced calcium concentration and IP3 in SMC.

  14. Aerobic interval training partly reverse contractile dysfunction and impaired Ca2+ handling in atrial myocytes from rats with post infarction heart failure

    OpenAIRE

    Johnsen, Anne Berit; Høydal, Morten Andre; Røsbjørgen, Ragnhild; Stølen, Tomas; Wisløff, Ulrik

    2013-01-01

    Background: There is limited knowledge about atrial myocyte Ca2+ handling in the failing hearts. The aim of this study was to examine atrial myocyte contractile function and Ca2+ handling in rats with post-infarction heart failure (HF) and to examine whether aerobic interval training could reverse a potential dysfunction. Methods and results: Post-infarction HF was induced in Sprague Dawley rats by ligation of the left descending coronary artery. Atrial myocyte shortening was depressed (p

  15. Aerobic Interval Training Partly Reverse Contractile Dysfunction and Impaired Ca2+ Handling in Atrial Myocytes from Rats with Post Infarction Heart Failure

    OpenAIRE

    Johnsen, Anne Berit; Høydal, Morten; Røsbjørgen, Ragnhild; Stølen, Tomas; Wisløff, Ulrik

    2013-01-01

    Background There is limited knowledge about atrial myocyte Ca2+ handling in the failing hearts. The aim of this study was to examine atrial myocyte contractile function and Ca2+ handling in rats with post-infarction heart failure (HF) and to examine whether aerobic interval training could reverse a potential dysfunction. Methods and results Post-infarction HF was induced in Sprague Dawley rats by ligation of the left descending coronary artery. Atrial myocyte shortening was depressed (p

  16. Obesity Resistance Promotes Mild Contractile Dysfunction Associated with Intracellular Ca2+ Handling

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    Felipe Gonçalves dos Santos de Sá

    2015-01-01

    Full Text Available AbstractBackground:Diet-induced obesity is frequently used to demonstrate cardiac dysfunction. However, some rats, like humans, are susceptible to developing an obesity phenotype, whereas others are resistant to that.Objective:To evaluate the association between obesity resistance and cardiac function, and the impact of obesity resistance on calcium handling.Methods:Thirty-day-old male Wistar rats were distributed into two groups, each with 54 animals: control (C; standard diet and obese (four palatable high-fat diets for 15 weeks. After the experimental protocol, rats consuming the high-fat diets were classified according to the adiposity index and subdivided into obesity-prone (OP and obesity-resistant (OR. Nutritional profile, comorbidities, and cardiac remodeling were evaluated. Cardiac function was assessed by papillary muscle evaluation at baseline and after inotropic maneuvers.Results:The high-fat diets promoted increase in body fat and adiposity index in OP rats compared with C and OR rats. Glucose, lipid, and blood pressure profiles remained unchanged in OR rats. In addition, the total heart weight and the weight of the left and right ventricles in OR rats were lower than those in OP rats, but similar to those in C rats. Baseline cardiac muscle data were similar in all rats, but myocardial responsiveness to a post-rest contraction stimulus was compromised in OP and OR rats compared with C rats.Conclusion:Obesity resistance promoted specific changes in the contraction phase without changes in the relaxation phase. This mild abnormality may be related to intracellular Ca2+ handling.

  17. The morphological changes of cardiomyocytes and mitochondrial dysfunction in spontaneous hypertensive rats with experimental diabetes mellitus

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    Kolesnyk M.Yu.

    2013-01-01

    Full Text Available The conception of energetic deficiency in the pathogenesis of arterial hypertension and diabetes mellitus presents new perspectives in the understanding of molecular and biochemical mechanisms of these diseases. It was performed the comparison between morphological changes and mitochondrial dysfunction in spontaneous hypertensive rats with experimental diabetes mellitus. The mitochondrial state was assessed by investigation of the permeability of the giant mitochondrial pore. It was found that the permeability of mitochondrial pore is increased in spontaneous hypertensive rats. It was registrated the significant increasing of mitochondrial membrane permeability in case of diabetes. It was observed the increased area of cardiomyocytes’ nuclei and decreased nuclear cytoplasmic ratio in diabetic animals. It was demonstrated that nucleic and cytoplasmic RNA concentration is decreased in comparison with the intact spontaneous hypertensive rats. The RNA biosynthesis abnormalities are associated with the degree of mitochondrial dysfunction in the myocardium of spontaneous hypertensive rats with experimental diabetes mellitus.

  18. Aerobic interval training partly reverse contractile dysfunction and impaired Ca2+ handling in atrial myocytes from rats with post infarction heart failure.

    Directory of Open Access Journals (Sweden)

    Anne Berit Johnsen

    Full Text Available BACKGROUND: There is limited knowledge about atrial myocyte Ca(2+ handling in the failing hearts. The aim of this study was to examine atrial myocyte contractile function and Ca(2+ handling in rats with post-infarction heart failure (HF and to examine whether aerobic interval training could reverse a potential dysfunction. METHODS AND RESULTS: Post-infarction HF was induced in Sprague Dawley rats by ligation of the left descending coronary artery. Atrial myocyte shortening was depressed (p<0.01 and time to relaxation was prolonged (p<0.01 in sedentary HF-rats compared to healthy controls. This was associated with decreased Ca(2+ amplitude, decreased SR Ca(2+ content, and slower Ca(2+ transient decay. Atrial myocytes from HF-rats had reduced sarcoplasmic reticulum Ca(2+ ATPase activity, increased Na(+/Ca(2+-exchanger activity and increased diastolic Ca(2+ leak through ryanodine receptors. High intensity aerobic interval training in HF-rats restored atrial myocyte contractile function and reversed changes in atrial Ca(2+ handling in HF. CONCLUSION: Post infarction HF in rats causes profound impairment in atrial myocyte contractile function and Ca(2+ handling. The observed dysfunction in atrial myocytes was partly reversed after aerobic interval training.

  19. Morfologia e contratilidade em cardiomiócitos de ratos com baixo desempenho para o exercício físico Morphology and contractility in cardiomyocytes of rats with low exercise performance

    Directory of Open Access Journals (Sweden)

    Judson Fonseca Quintão Júnior

    2012-05-01

    Full Text Available FUNDAMENTO: A capacidade aeróbica é fundamental para o desempenho físico, e a baixa capacidade aeróbica está relacionada ao desencadeamento de diversas doenças cardiovasculares. OBJETIVO: Comparar a contratilidade e a morfologia de cardiomiócitos isolados de ratos com baixo desempenho e desempenho padrão para o exercício físico. MÉTODOS: Ratos Wistar, com 10 semanas de idade, foram submetidos a um protocolo de corrida em esteira até a fadiga, e foram divididos em dois grupos: Baixo Desempenho (BD e Desempenho Padrão (DP. Em seguida, após eutanásia, o coração foi removido rapidamente e, por meio de dissociação enzimática, os cardiomiócitos do ventrículo esquerdo foram isolados. O comprimento celular e dos sarcômeros e a largura dos cardiomiócitos foram medidos usando-se um sistema de detecção de bordas. Os cardiomiócitos isolados foram estimulados eletricamente a 1 e 3 Hz e a contração celular foi medida registrando-se a alteração do seu comprimento. RESULTADOS: O comprimento celular foi menor no grupo BD (157,2 ± 1,3µm; p BACKGROUND: Aerobic capacity is essential to physical performance, and low aerobic capacity is related to the triggering of various cardiovascular diseases. OBJECTIVE: To compare the morphology and contractility of isolated rat cardiomyocytes with low performance and standard performance for exercise. METHODS: Wistar rats with 10 weeks of age underwent a protocol of treadmill running to fatigue, and were divided into two groups: Low Performance (LP and Standard Performance (SP. Then, the animals were sacrificed, the heart was quickly removed and, by means of enzymatic dissociation, left ventricular cardiomyocytes were isolated. The cell and sarcomeres length and width of cardiomyocytes were measured using an edge detection system. The isolated cardiomyocytes were electrically stimulated at 1 and 3 Hz and cell contraction was measured by registering the change of their length. RESULTS: The cell

  20. Abnormal Calcium "Sparks" in Cardiomyocytes of Post-myocardial Infarction Heart

    Institute of Scientific and Technical Information of China (English)

    Kai HUANG; Dan HUANG; Shengquan FU; Chongzhe YANG; Yuhua LIAO

    2008-01-01

    In ischemic hypertrophic myocardium, contractile dysfunction can be attributed to the decreased calcium induced calcium release (CICR) in cytoplasm. This study aimed to investigate the electrophysiological properties and the expression of L calcium channel subunits in post-MI myocardium. The ischemic heart remodeling model was established in SD rats. The expressions of calcium channel subunits were determined by realtime RT-PCR. Whole cell patch clamp was used to record the electrophysiological properties of L calcium channel. The results showed that the L calcium channel agonist Bayk 8644 induced the significantly decreased CICR in the rat cardiomyocyte 6weeks after myocardial infarction (MI). In the post-MI cardiomyocytes, the amplitude of ICaL decreased dramatically and the inactivation curve of the current shifted to more negative potential. At mRNA level, the expression of the calcium channel alphalc, beta2c subunits decreased dramatically in the ventricle of post-MI rats. The expression of alpha2/delta subunit, however, remained constant.It is concluded that the abnormal expression of the L calcium channel subunits in post-MI cardiomyocytes contributes to the ICaL decrease at early stage of the ischemic remodeling in cardiomyocytes,which leads to the decreased CICR in the cell and contractile dysfunction of myocardium.

  1. Quantitative circumferential strain analysis using adenosine triphosphate-stress/rest 3-T tagged magnetic resonance to evaluate regional contractile dysfunction in ischemic heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Masashi, E-mail: m.nakamura1230@gmail.com [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan); Kido, Tomoyuki [Department of Radiology, Saiseikai Matsuyama Hospital, Ehime 791-0295 (Japan); Kido, Teruhito; Tanabe, Yuki; Matsuda, Takuya; Nishiyama, Yoshiko; Miyagawa, Masao; Mochizuki, Teruhito [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan)

    2015-08-15

    Highlights: • Infarcted segments could be differentiated from non-ischemic and ischemic segments with high sensitivity and specificity under at rest conditions. • The time-to-peak circumferential strain values in infarcted segments were more significantly delayed than those in non-ischemic and ischemic segments. • Both circumferential strain and circumferential systolic strain rate values under ATP-stress conditions were significantly lower in ischemic segments than in non-ischemic segments. • Subtracting stress and rest circumferential strain had a higher diagnostic capability for ischemia relative to only utilizing rest or ATP-stress circumferential strain values. • A circumferential strain analysis using tagged MR can quantitatively assess contractile dysfunction in ischemic and infarcted myocardium. - Abstract: Purpose: We evaluated whether a quantitative circumferential strain (CS) analysis using adenosine triphosphate (ATP)-stress/rest 3-T tagged magnetic resonance (MR) imaging can depict myocardial ischemia as contractile dysfunction during stress in patients with suspected coronary artery disease (CAD). We evaluated whether it can differentiate between non-ischemia, myocardial ischemia, and infarction. We assessed its diagnostic performance in comparison with ATP-stress myocardial perfusion MR and late gadolinium enhancement (LGE)-MR imaging. Methods: In 38 patients suspected of having CAD, myocardial segments were categorized as non-ischemic (n = 485), ischemic (n = 74), or infarcted (n = 49) from the results of perfusion MR and LGE-MR. The peak negative CS value, peak circumferential systolic strain rate (CSR), and time-to-peak CS were measured in 16 segments. Results: A cutoff value of −12.0% for CS at rest allowed differentiation between infarcted and other segments with a sensitivity of 79%, specificity of 76%, accuracy of 76%, and an area under the curve (AUC) of 0.81. Additionally, a cutoff value of 477.3 ms for time-to-peak CS at rest

  2. Reduced function and disassembled microtubules of cultured cardiomyocytes in spaceflight

    Institute of Scientific and Technical Information of China (English)

    YANG Fen; DAI ZhongQuan; TAN YingJun; WAN YuMin; LI YingHui; DING Bai; NIE JieLin; WANG HongHui; ZHANG XiaoYou; WANG ChunYan; LING ShuKuan; NI ChengZhi

    2008-01-01

    Lack of gravity during spaceflight has profound effects on cardiovascular system, but little is known about how the cardiomyocytes respond to microgravity. In the present study, the effects of spaceflight on the structure and function of cultured cardiomyocytes were reported. The primary cultures of neo-natal rat cardiomyocytes were carried on Shenzhou-6 spacecraft and activated at 4 h in orbit. 8 samples were fixed respectively at 4, 48 and 96 h after launching for immunofluorescence of cytoskeleton, and 2 samples remained unfixed to analyze contractile and secretory functions of the cultures. Ground sam-ples were treated in our laboratory in parallel. After 115 h spaceflight, video recordings displayed that the number of spontaneous beating sites in flown samples decreased significantly, and the cells in the beating aggregate contracted in fast frequency without synchrony. Radioimmunoassay of the medium showed that the atrial natriuretic peptide secreted from flown cells reduced by 59.6%. Confocal images demonstrated the time-dependant disassembly of mirotubules versus unchanged distribution and or-ganization of microfilaments. In conclusion, above results indicate reduced function and disorganized cytoskeleton of cardiomyocytes in spaceflight, which might provide some cellular basis for further investigations to probe into the mechanisms underlying space cardiovascular dysfunction.

  3. Mechanisms involved in the in vitro contractile dysfunction induced by different concentrations of ferrous iron in the rat myocardium.

    Science.gov (United States)

    Ávila, Renata Andrade; Silva, Marito Afonso Sousa Costa; Peixoto, João Victor; Kassouf-Silva, Ilana; Fogaça, Rosalvo T H; Dos Santos, Leonardo

    2016-10-01

    Iron intoxication is related to reactive oxygen species (ROS) production and organic damage including the cardiovascular system, and is a leading cause of poisoning deaths in children. In this study we examined whether a range of ferrous iron (Fe(2+)) concentrations can interfere differently on the myocardial mechanics, investigating the ROS-mediated effects. Developed force of isolated rat papillary muscles was depressed with a concentration- and time-dependency by Fe(2+) 100-1000μM. The contractile response to Ca(2+) was reduced, but it was partially reversed by co-incubation with catalase and DMSO, but not TEMPOL. In agreement, in situ detection of OH was increased by Fe(2+) whereas O2(-) was unchanged. The myosin-ATPase activity was significantly decreased. Contractions dependent on the sarcolemal Ca(2+) influx were impaired only by Fe(2+) 1000μM, and antioxidants had no effect. In skinned fibers, Fe(2+) reduced the pCa-force relationship, and pCa50 was right-shifted by 0.55. In conclusion, iron overload can acutely impair myocardial contractility by reducing myosin-ATPase activity and myofibrillar Ca(2+) sensitivity. These effects are mediated by local production of OH and H2O2. Nevertheless, in a such high concentration as 1000μM, Fe(2+) appears to depress force also by reducing Ca(2+) influx, probably due to a competition at Ca(2+) channels. PMID:27396687

  4. Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling.

    Directory of Open Access Journals (Sweden)

    Jiaojiao Pang

    Full Text Available The endoplasmic reticulum (ER plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH.ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs. Myocardial mechanical and intracellular Ca(2+ properties, ER stress, autophagy and associated cell signaling molecules were evaluated.ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca(2+ homeostasis, oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62, along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene.Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy.

  5. Muscle contractile and metabolic dysfunction is a common feature of sarcopenia of aging and chronic diseases: from sarcopenic obesity to cachexia.

    Science.gov (United States)

    Biolo, Gianni; Cederholm, Tommy; Muscaritoli, Maurizio

    2014-10-01

    Skeletal muscle is the most abundant body tissue accounting for many physiological functions. However, muscle mass and functions are not routinely assessed. Sarcopenia is defined as skeletal muscle loss and dysfunction in aging and chronic diseases. Inactivity, inflammation, age-related factors, anorexia and unbalanced nutrition affect changes in skeletal muscle. Mechanisms are difficult to distinguish in individual subjects due to the multifactorial character of the condition. Sarcopenia includes both muscle loss and dysfunction which induce contractile impairment and metabolic and endocrine abnormalities, affecting whole-body metabolism and immune/inflammatory response. There are different metabolic trajectories for muscle loss versus fat changes in aging and chronic diseases. Appetite regulation and physical activity affect energy balance and changes in body fat mass. Appetite regulation by inflammatory mediators is poorly understood. In some patients, inflammation induces anorexia and fat loss in combination with sarcopenia. In others, appetite is maintained, despite activation of systemic inflammation, leading to sarcopenia with normal or increased BMI. Inactivity contributes to sarcopenia and increased fat tissue in aging and diseases. At the end of the metabolic trajectories, cachexia and sarcopenic obesity are paradigms of the two patient categories. Pre-cachexia and cachexia are observed in patients with cancer, chronic heart failure or liver cirrhosis. Sarcopenic obesity and sarcopenia with normal/increased BMI are observed in rheumatoid arthritis, breast cancer patients with adjuvant chemotherapy and in most of patients with COPD or chronic kidney disease. In these conditions, sarcopenia is a powerful prognostic factor for morbidity and mortality, independent of BMI.

  6. Cardiomyocyte Regeneration

    Directory of Open Access Journals (Sweden)

    Toshio Nakanishi

    2013-01-01

    Full Text Available The heart was initially believed to be a terminally differentiated organ; once the cardiomyocytes died, no recovery could be made to replace the dead cells. However, around a decade ago, the concept of cardiac stem cells (CSCs in adult hearts was proposed. CSCs differentiate into cardiomyocytes, keeping the heart functioning. Studies have proved the existence of stem cells in the heart. These somatic stem cells have been studied for use in cardiac regeneration. Moreover, recently, induced pluripotent stem cells (iPSCs were invented, and methodologies have now been developed to induce stable cardiomyocyte differentiation and purification of mature cardiomyocytes. A reprogramming method has also been applied to direct reprogramming using cardiac fibroblasts into cardiomyocytes. Here, we address cardiomyocyte differentiation of CSCs and iPSCs. Furthermore, we describe the potential of CSCs in regenerative biology and regenerative medicine.

  7. Endothelial-Cardiomyocyte Interactions in Cardiac Development and Repair

    Science.gov (United States)

    Hsieh, Patrick C.H.; Davis, Michael E.; Lisowski, Laura K.; Lee, Richard T.

    2009-01-01

    Communication between endothelial cells and cardiomyocytes regulates not only early cardiac development but also adult cardiomyocyte function, including the contractile state. In the normal mammalian myocardium, each cardiomyocyte is surrounded by an intricate network of capillaries and is next to endothelial cells. Cardiomyocytes depend on endothelial cells not only for oxygenated blood supply but also for local protective signals that promote cardiomyocyte organization and survival. While endothelial cells direct cardiomyocytes, cardiomyocytes reciprocally secrete factors that impact endothelial cell function. Understanding how endothelial cells communicate with cardiomyocytes will be critical for cardiac regeneration, in which the ultimate goal is not simply to improve systolic function transiently but to establish new myocardium that is both structurally and functionally normal in the long term. PMID:16460266

  8. Liensinine- and Neferine-Induced Cardiotoxicity in Primary Neonatal Rat Cardiomyocytes and Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Yangyang Yu

    2016-01-01

    Full Text Available Due to drug-induced potential congestive heart failure and irreversible dilated cardiomyopathies, preclinical evaluation of cardiac dysfunction is important to assess the safety of traditional or novel treatments. The embryos of Nelumbo nucifera Gaertner seeds are a homology of traditional Chinese medicine and food. In this study, we applied the real time cellular analysis (RTCA Cardio system, which can real-time monitor the contractility of cardiomyocytes (CMs, to evaluate drug safety in rat neonatal CMs and human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs. This study showed detailed biomechanical CM contractility in vitro, and provided insights into the cardiac dysfunctions associated with liensinine and neferine treatment. These effects exhibited dose and time-dependent recovery. Neferine showed stronger blocking effect in rat neonatal CMs than liensinine. In addition, the effects of liensinine and neferine were further evaluated on hiPS-CMs. Our study also indicated that both liensinine and neferine can cause disruption of calcium homeostasis. For the first time, we demonstrated the potential cardiac side effects of liensinine or neferine. While the same inhibition was observed on hiPS-CMs, more importantly, this study introduced an efficient and effective approach to evaluate the cardiotoxicity of the existing and novel drug candidates.

  9. Cardiomyocytic apoptosis and heart failure

    Institute of Scientific and Technical Information of China (English)

    Quanzhou Feng

    2008-01-01

    Heart failure is a major disease seriously threatening human health.Once left ventricular dysfunction develops,cardiac function usually deteriorates and progresses to congestive heart failure in several months or years even if no factors which accelerate the deterioration repeatedly exist.Mechanism through which cardiac function continually deteriorates is still unclear.Cardiomyocytic apoptosis can occur in acute stage of ischemic heart diseases and the compensated stage of cardiac dysfunction.In this review,we summarize recent advances in understanding the role of cardiomyocytic apoptosis in heart failure.

  10. Myocardial contractility

    Energy Technology Data Exchange (ETDEWEB)

    Comet, M.; Machecourt, J.

    1988-01-01

    The myocardial contractility characterizes the intensity of the activation representing the globality of the processes which lead to the formation of the sites where the strength is generated. Some parameters allowing a quantification of the contractility are measured during the isovolumic phase of the ventricular contraction: they are essentially dP/dt/sub max/, and eventually V/sub max/. For the measurement of these parameters, a pressure detector needs to be introduced into the left ventricle. Other parameters are measured during the systolic ejection phase: they are the ejection fraction, which is easy to measure and is very load dependant, and the maximal elastance. This last parameter is not easy to measure, but seems load independant. With the radioisotopes, it is possible to measure the ejection fraction and the maximal elastance. Contractility measurements are of interest in the study of ischemic cardiopathies and of valvular desease.

  11. Coronary microembolization induced myocardial contractile dysfunction and tumor necrosis factor-α mRNA expression partly inhibited by SB203580 through a p38 mitogen-activated protein kinase pathway

    Institute of Scientific and Technical Information of China (English)

    LI Lang; QU Nan; LI Dong-hua; WEN Wei-ming; HUANG Wei-qiang

    2011-01-01

    Background The microemboli produced during spontaneous plaque rupture and ulceration and during coronary intervention will reduce coronary reserve and cause cardiac dysfunction. It is though that inflammation caused by the microinfarction induced by the microembolization may play an essential role. It is known that the activation of p38mitogen-activated protein kinases (MAPK) in both infected and non-infected inflammation in myocardium may cause a contractile dysfunction. But the relation between the activation of p38 MAPK and microembolization is still unknown.Methods Sprague-Dawley rats were randomly divided into three groups: Sham group, coronary microembolization (CME) group and SB203580 group (n=10 per group). CME rats were produced by injection of 42 μm microspheres into the left ventricle with occlusion of the ascending aorta. SB203580, a p38 MAPK inhibitor, was injected into the femoral vein after the injection of microspheres to make the SB203580 group. Left ventricular ejection fraction (LVEF) was determined by echocardiography. The protein concentration of P38 MAPK in the myocardium was assessed by Western blotting. The relative expression of mRNA for tumor necrosis factor (TNF)-a was assessed by the technique of semi-quantitative polymerase chain reaction amplification.Results LVEF was depressed at three hours up to 12 hours in the CME group. Increased p38 MAPK activity and TNF-α mRNA expression were observed in the CME group. The administration of SB203580 partly inhibited p38 MAPK activity,but did not fully depress the TNF-α expression, and partly preserved cardiac contractile function.Conclusions p38 MAPK is significantly activated by CME and the inhibition of p38 MAPK can partly depress the TNF-α expression and preserve cardiac contractile function.

  12. Acidosis-induced p38 MAPK activation and its implication in regulation of cardiac contractility

    Institute of Scientific and Technical Information of China (English)

    Ming ZHENG; Rong HOU; Rui-ping XIAO

    2004-01-01

    AIM: To determine the possible role of pH in mediating activation of p38 mitogen-activated protein kinase (MAPK) and the consequent function of activated p38 MAPK in regulating cardiac contractility. METHODS: Adult rat cardiomyocytes were isolated and cultured. Low pH media was used to induce intracellular acidosis and contraction of single cardiomyocyte was measured. RESULTS: Phosphorylation of p38 MAPK was increased during ischemia, and pHi was decreased. Intracellular acidosis activated p38 MAPK to a similar level as ischemia. Inhibition of p38 MAPK activation by SB203580, a specific inhibitor of p38 MAPK, reversed acidosis-mediated reduction of myocyte contractility. CONCLUSION: In adult rat cardiomyocytes, intracellular acidification activated p38 MAPK and decreased cardiac contractility. Pretreatment of cardiomyocytes with SB203580 completely blocked p38 MAPK activation and partially reversed acidosis-mediated decline of cardiac contractility.

  13. Protein kinase B (PKB/AKT1) formed signaling complexes with mitochondrial proteins and prevented glycolytic energy dysfunction in cultured cardiomyocytes during ischemia-reperfusion injury.

    Science.gov (United States)

    Deng, Wu; Leu, Hsin-Bang; Chen, Yumay; Chen, Yu-Han; Epperson, Christine M; Juang, Charity; Wang, Ping H

    2014-05-01

    Our previous studies showed that insulin stimulated AKT1 translocation into mitochondria and modulated oxidative phosphorylation complex V in cardiac muscle. This raised the possibility that mitochondrial AKT1 may regulate glycolytic oxidative phosphorylation and mitochondrial function in cardiac muscle cells. The aims of this project were to study the effects of mitochondrial AKT1 signaling on cell survival in stressed cardiomyocytes, to define the effect of mitochondrial AKT1 signaling on glycolytic bioenergetics, and to identify mitochondrial targets of AKT1 signaling in cardiomyocytes. Mitochondrial AKT1 signaling played a protective role against apoptosis and necrosis during ischemia-reperfusion stress, suppressed mitochondrial calcium overload, and alleviated mitochondrial membrane depolarization. Activation of AKT1 signaling in mitochondria increased glucose uptake, enhanced respiration efficiency, reduced superoxide generation, and increased ATP production in the cardiomyocytes. Inhibition of mitochondrial AKT attenuated insulin response, indicating that insulin regulation of ATP production required mitochondrial AKT1 signaling. A proteomic approach was used to reveal 15 novel targets of AKT1 signaling in mitochondria, including pyruvate dehydrogenase complex (PDC). We have confirmed and characterized the association of AKT1 and PDC subunits and verified a stimulatory effect of mitochondrial AKT1 on the enzymatic activity of PDC. These findings suggested that AKT1 formed protein complexes with multiple mitochondrial proteins and improved mitochondrial function in stressed cardiomyocytes. The novel AKT1 signaling targets in mitochondria may become a resource for future metabolism research.

  14. From fetus towards adult : maturation and functional analysis of pluripotent stem cell-derived cardiomyocytes

    NARCIS (Netherlands)

    Catarino, Ribeiro M.

    2016-01-01

    This thesis describes research about the differentiation of human stem cells into cardiomyocytes (heart cells). During the differentiation process the stem cells become contractile myocytes that resemble the native heart cells. Nevertheless, the phenotype of these cardiomyocytes is comparable to a s

  15. Peptide-based inhibition of NF-κB rescues diaphragm muscle contractile dysfunction in a murine model of Duchenne muscular dystrophy.

    Science.gov (United States)

    Peterson, Jennifer M; Kline, William; Canan, Benjamin D; Ricca, Daniel J; Kaspar, Brian; Delfín, Dawn A; DiRienzo, Kelly; Clemens, Paula R; Robbins, Paul D; Baldwin, Albert S; Flood, Pat; Kaumaya, Pravin; Freitas, Michael; Kornegay, Joe N; Mendell, Jerry R; Rafael-Fortney, Jill A; Guttridge, Denis C; Janssen, Paul M L

    2011-01-01

    Deterioration of diaphragm function is one of the prominent factors that contributes to the susceptibility of serious respiratory infections and development of respiratory failure in patients with Duchenne Muscular Dystrophy (DMD). The NF-κB signaling pathway has been implicated as a contributing factor of dystrophic pathology, making it a potential therapeutic target. Previously, we demonstrated that pharmacological inhibition of NF-κB via a small NEMO Binding Domain (NBD) peptide was beneficial for reducing pathological features of mdx mice. Now, we stringently test the effectiveness and clinical potential of NBD by treating mdx mice with various formulations of NBD and use diaphragm function as our primary outcome criteria. We found that administering DMSO-soluble NBD rescued 78% of the contractile deficit between mdx and wild-type (WT) diaphragm. Interestingly, synthesis of a GLP NBD peptide as an acetate salt permitted its solubility in water, but as a negative consequence, also greatly attenuated functional efficacy. However, replacing the acetic acid counterion of the NBD peptide with trifluoroacetic acid retained the peptide's water solubility and significantly restored mdx diaphragm contractile function and improved histopathological indices of disease in both diaphragm and limb muscle. Together, these results support the feasibility of using a mass-produced, water-soluble NBD peptide for clinical use. PMID:21267511

  16. Transgenic mice with cardiac-specific expression of activating transcription factor 3, a stress-inducible gene, have conduction abnormalities and contractile dysfunction.

    Science.gov (United States)

    Okamoto, Y; Chaves, A; Chen, J; Kelley, R; Jones, K; Weed, H G; Gardner, K L; Gangi, L; Yamaguchi, M; Klomkleaw, W; Nakayama, T; Hamlin, R L; Carnes, C; Altschuld, R; Bauer, J; Hai, T

    2001-08-01

    Activating transcription factor 3 (ATF3) is a member of the CREB/ATF family of transcription factors. Previously, we demonstrated that the expression of the ATF3 gene is induced by many stress signals. In this report, we demonstrate that expression of ATF3 is induced by cardiac ischemia coupled with reperfusion (ischemia-reperfusion) in both cultured cells and an animal model. Transgenic mice expressing ATF3 under the control of the alpha-myosin heavy chain promoter have atrial enlargement, and atrial and ventricular hypertrophy. Microscopic examination showed myocyte degeneration and fibrosis. Functionally, the transgenic heart has reduced contractility and aberrant conduction. Interestingly, expression of sorcin, a gene whose product inhibits the release of calcium from sarcoplasmic reticulum, is increased in these transgenic hearts. Taken together, our results indicate that expression of ATF3, a stress-inducible gene, in the heart leads to altered gene expression and impaired cardiac function. PMID:11485922

  17. Molecular and biochemical evidence on the protection of cardiomyocytes from phosphine-induced oxidative stress, mitochondrial dysfunction and apoptosis by acetyl-L-carnitine.

    Science.gov (United States)

    Baghaei, Amir; Solgi, Reza; Jafari, Abbas; Abdolghaffari, Amir Hossein; Golaghaei, Alireza; Asghari, Mohammad Hossein; Baeeri, Maryam; Ostad, Seyed Nasser; Sharifzadeh, Mohammad; Abdollahi, Mohammad

    2016-03-01

    The aim of the present study was to investigate the efficacy of acetyl-L-carnitine (ALCAR) on pathologic changes of mitochondrial respiratory chain activity, ATP production, oxidative stress, and cellular apoptosis/necrosis induced by aluminum phosphide (AlP) poisoning. The study groups included: the Sham that received almond oil only; the AlP that received oral LD50 dose of aluminum; the AC-100, AC-200, and AC-300 which received concurrent oral LD50 dose of AlP and single 100, 200, and 300 mg/kg of ALCAR by intraperitoneal injection. After 24 h, the rats were sacrificed; the heart and blood sample were taken for measurement of biochemical and mitochondrial factors. The results specified that ALCAR significantly attenuated the oxidative stress (elevated ROS and plasma iron levels) caused by AlP poisoning. ALCAR also increased the activity of cytochrome oxidase, which in turn amplified ATP production. Furthermore, flow cytometric assays and caspase activity indicated that ALCAR prohibited AlP-induced apoptosis in cardiomyocytes. PMID:26773361

  18. Human Engineered Heart Tissue: Analysis of Contractile Force

    OpenAIRE

    Ingra Mannhardt; Kaja Breckwoldt; David Letuffe-Brenière; Sebastian Schaaf; Herbert Schulz; Christiane Neuber; Anika Benzin; Tessa Werner; Alexandra Eder; Thomas Schulze; Birgit Klampe; Torsten Christ; Marc N. Hirt; Norbert Huebner; Alessandra Moretti1

    2016-01-01

    Analyzing contractile force, the most important and best understood function of cardiomyocytes in vivo is not established in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). This study describes the generation of 3D, strip-format, force-generating engineered heart tissues (EHT) from hiPSC-CM and their physiological and pharmacological properties. CM were differentiated from hiPSC by a growth factor-based three-stage protocol. EHTs were generated and analyzed histological...

  19. Recombinant proteins secreted from tissue-engineered bioartificial muscle improve cardiac dysfunction and suppress cardiomyocyte apoptosis in rats with heart failure

    Institute of Scientific and Technical Information of China (English)

    RONG Shu-ling; WANG Yong-jin; WANG Xiao-lin; LU Yong-xin; WU Yin; LIU Qi-yun; MI Shao-hua; XU Yu-lan

    2010-01-01

    secrete rhlGF-1 and tissue-engineered into implantable BAMs containing parallel arrays of postmitotic myofibers. In vitro, they secreted consistent levels of hIGF (0.4-1.2 μg·BAM-1·d-1). When implanted into syngeneic rat, IGF-BAMs secreted and delivered rhIGF. Four weeks after therapy,the hemodynamics was improved significantly in MI rats treated with IGF-BAMs compared with those treated with GFP-BAMs. The levels of serum IGF-1 were increased significantly in both MI and sham rats treated with IGF-BAM. The mRNA expression of bax was lower and Bcl-2 expression was higher in MI-IGF group than MI-GFP group (P <0.05).Western blotting assay showed TNF-α and caspase 3 expression was lower in MI-IGF group than MI-GFP group after therapy.Conclusions rhIGF-1 significantly improves left ventricular function and suppresses cardiomyocyte apoptosis in rats with chronic heart failure. Genetically modified tissue- engineered BAMs provide a method delivering recombinant protein for the treatment of heart failure.

  20. Cardiomyocyte behavior on biodegradable polyurethane/gold nanocomposite scaffolds under electrical stimulation

    OpenAIRE

    Ganji, Yasaman; Li, Qian; Quabius, Elgar Susanne; Böttner, Martina; Selhuber-Unkel, Christine; Kasra, Mehran

    2016-01-01

    Following a myocardial infarction (MI), cardiomyocytes are replaced by scar tissue, which decreases ventricular contractile function. Tissue engineering is a promising approach to regenerate such damaged cardiomyocyte tissue. Engineered cardiac patches can be fabricated by seeding a high density of cardiac cells onto a synthetic or natural porous polymer. In this study, nanocomposite scaffolds made of gold nanotubes/nanowires incorporat- ed into biodegradable castor oil-based poly...

  1. Increased Intracellular [dATP] Enhances Cardiac Contraction in Embryonic Chick Cardiomyocytes

    OpenAIRE

    Schoffstall, Brenda; Chase, P. Bryant

    2008-01-01

    Although ATP is the physiological substrate for cardiac contraction, cardiac contractility is significantly enhanced in vitro when only 10% of ATP substrate is replaced with 2’-deoxy-ATP (dATP). To determine the functional effects of increased intracellular [dATP] ([dATP]i) within living cardiac cells, we used hypertonic loading with varying exogenous dATP/ATP ratios, but constant total nucleotide concentration, to elevate [dATP]i in contractile monolayers of embryonic chick cardiomyocytes. T...

  2. Dysfunction of the CNS-heart axis in mouse models of Huntington's disease.

    Directory of Open Access Journals (Sweden)

    Michal Mielcarek

    2014-08-01

    Full Text Available Cardiac remodelling and contractile dysfunction occur during both acute and chronic disease processes including the accumulation of insoluble aggregates of misfolded amyloid proteins that are typical features of Alzheimer's, Parkinson's and Huntington's disease (HD. While HD has been described mainly as a neurological disease, multiple epidemiological studies have shown that HD patients exhibit a high incidence of cardiovascular events leading to heart failure, and that this is the second highest cause of death. Given that huntingtin is ubiquitously expressed, cardiomyocytes may be at risk of an HD-related dysfunction. In mice, the forced expression of an expanded polyQ repeat under the control of a cardiac specific promoter led to severe heart failure followed by reduced lifespan. However the mechanism leading to cardiac dysfunction in the clinical and pre-clinical HD settings remains unknown. To unravel this mechanism, we employed the R6/2 transgenic and HdhQ150 knock-in mouse models of HD. We found that pre-symptomatic animals developed connexin-43 relocation and a significant deregulation of hypertrophic markers and Bdnf transcripts. In the symptomatic animals, pronounced functional changes were visualised by cardiac MRI revealing a contractile dysfunction, which might be a part of dilatated cardiomyopathy (DCM. This was accompanied by the re-expression of foetal genes, apoptotic cardiomyocyte loss and a moderate degree of interstitial fibrosis. To our surprise, we could identify neither mutant HTT aggregates in cardiac tissue nor a HD-specific transcriptional dysregulation, even at the end stage of disease. We postulate that the HD-related cardiomyopathy is caused by altered central autonomic pathways although the pathogenic effects of mutant HTT acting intrinsically in the heart may also be a contributing factor.

  3. CARD9 knockout ameliorates myocardial dysfunction associated with high fat diet-induced obesity.

    Science.gov (United States)

    Cao, Li; Qin, Xing; Peterson, Matthew R; Haller, Samantha E; Wilson, Kayla A; Hu, Nan; Lin, Xin; Nair, Sreejayan; Ren, Jun; He, Guanglong

    2016-03-01

    Obesity is associated with chronic inflammation which plays a critical role in the development of cardiovascular dysfunction. Because the adaptor protein caspase recruitment domain-containing protein 9 (CARD9) in macrophages regulates innate immune responses via activation of pro-inflammatory cytokines, we hypothesize that CARD9 mediates the pro-inflammatory signaling associated with obesity en route to myocardial dysfunction. C57BL/6 wild-type (WT) and CARD9(-/-) mice were fed normal diet (ND, 12% fat) or a high fat diet (HFD, 45% fat) for 5months. At the end of 5-month HFD feeding, cardiac function was evaluated using echocardiography. Cardiomyocytes were isolated and contractile properties were measured. Immunofluorescence was performed to detect macrophage infiltration in the heart. Heart tissue homogenates, plasma, and supernatants from isolated macrophages were collected to measure the concentrations of pro-inflammatory cytokines using ELISA kits. Western immunoblotting analyses were performed on heart tissue homogenates and isolated macrophages to explore the underlying signaling mechanism(s). CARD9 knockout alleviated HFD-induced insulin resistance and glucose intolerance, prevented myocardial dysfunction with preserved cardiac fractional shortening and cardiomyocyte contractile properties. CARD9 knockout also significantly decreased the number of infiltrated macrophages in the heart with reduced myocardium-, plasma-, and macrophage-derived cytokines including IL-6, IL-1β and TNFα. Finally, CARD9 knockout abrogated the increase of p38 MAPK phosphorylation, the decrease of LC3BII/LC3BI ratio and the up-regulation of p62 expression in the heart induced by HFD feeding and restored cardiac autophagy signaling. In conclusion, CARD9 knockout ameliorates myocardial dysfunction associated with HFD-induced obesity, potentially through reduction of macrophage infiltration, suppression of p38 MAPK phosphorylation, and preservation of autophagy in the heart. PMID

  4. Prevalencia de disfunción cardiaca contráctil y tiroidea en pacientes con taquicardia sinusual inapropiada Cardiac Contractile and Thyroid Dysfunction in Patients with Inappropriate Sinus Tachycardia

    Directory of Open Access Journals (Sweden)

    Oswaldo Gutiérrez-Sotelo

    2010-03-01

    the prevalence of cardiac contractile and thyroid dysfunction Materials and methods: We selected from all 24 hour Holter studies performed during 2006 at the Cardiology Service of the México Hospital (Costa Rica those of patients with inappropriate sinus tachycardia, defined as mean heart rate equal o greater than 80 beats per minute (bpm or multiple episodes of sinus tachycardia without physiologic explanation. We analyzed demographic data, echocardiographic presence or absence of systolic cardiac dysfunction and thyroid function by means of TSH and total T3-4. We excluded from the analysis those patients with known cardiac disease. Results: We selected 105 Holter registries from 380 studies, 27,6% or 81 were women, and 24 men. Mean age was 38,97 years old (range 9-81. The mean heart rate was 86,23 bpm (108-71, mean maximal heart rate 143,19 (189-111 and mean minimal heart rate 55,7 (89-22 bpm. In 49 patients an ejection fraction was available; a normal mean value of 0,6 (0,7-0,45 was reported. In 29 patients thyroid function tests were obtained and the mean value of free-T4 y TSH were between normal limits (1,48 ng/dL and 1,7 mUI/L respectively. Conclusion: The majority of patients consulting for palpitations and in whom a Holter analysis results in inappropriate sinus tachycardia, have no cardiac contractility nor thyroid dysfunction. Therefore, in this group of patients it is not justified to evaluate these parameters routinely.

  5. Inhibition of Receptor Interacting Protein Kinases Attenuates Cardiomyocyte Hypertrophy Induced by Palmitic Acid

    OpenAIRE

    Mingyue Zhao; Lihui Lu; Song Lei; Hua Chai; Siyuan Wu; Xiaoju Tang; Qinxue Bao; Li Chen; Wenchao Wu; Xiaojing Liu

    2016-01-01

    Palmitic acid (PA) is known to cause cardiomyocyte dysfunction. Cardiac hypertrophy is one of the important pathological features of PA-induced lipotoxicity, but the mechanism by which PA induces cardiomyocyte hypertrophy is still unclear. Therefore, our study was to test whether necroptosis, a receptor interacting protein kinase 1 and 3 (RIPK1 and RIPK3-) dependent programmed necrosis, was involved in the PA-induced cardiomyocyte hypertrophy. We used the PA-treated primary neonatal rat cardi...

  6. A device for rapid and quantitative measurement of cardiac myocyte contractility

    Science.gov (United States)

    Gaitas, Angelo; Malhotra, Ricky; Li, Tao; Herron, Todd; Jalife, José

    2015-03-01

    Cardiac contractility is the hallmark of cardiac function and is a predictor of healthy or diseased cardiac muscle. Despite advancements over the last two decades, the techniques and tools available to cardiovascular scientists are limited in their utility to accurately and reliably measure the amplitude and frequency of cardiomyocyte contractions. Isometric force measurements in the past have entailed cumbersome attachment of isolated and permeabilized cardiomyocytes to a force transducer followed by measurements of sarcomere lengths under conditions of submaximal and maximal Ca2+ activation. These techniques have the inherent disadvantages of being labor intensive and costly. We have engineered a micro-machined cantilever sensor with an embedded deflection-sensing element that, in preliminary experiments, has demonstrated to reliably measure cardiac cell contractions in real-time. Here, we describe this new bioengineering tool with applicability in the cardiovascular research field to effectively and reliably measure cardiac cell contractility in a quantitative manner. We measured contractility in both primary neonatal rat heart cardiomyocyte monolayers that demonstrated a beat frequency of 3 Hz as well as human embryonic stem cell-derived cardiomyocytes with a contractile frequency of about 1 Hz. We also employed the β-adrenergic agonist isoproterenol (100 nmol l-1) and observed that our cantilever demonstrated high sensitivity in detecting subtle changes in both chronotropic and inotropic responses of monolayers. This report describes the utility of our micro-device in both basic cardiovascular research as well as in small molecule drug discovery to monitor cardiac cell contractions.

  7. Excitation model of pacemaker cardiomyocytes of cardiac conduction system

    Science.gov (United States)

    Grigoriev, M.; Babich, L.

    2015-11-01

    Myocardium includes typical and atypical cardiomyocytes - pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation - heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.

  8. An essential role for complement C5a in the pathogenesis of septic cardiac dysfunction

    OpenAIRE

    Niederbichler, Andreas D; Hoesel, Laszlo M.; Westfall, Margaret V.; Gao, Hongwei; Ipaktchi, Kyros R; Sun, Lei; Zetoune, Firas S.; Su, Grace L; Arbabi, Saman; Sarma, J. Vidya; Wang, Stewart C.; Hemmila, Mark R.; Ward, Peter A.

    2006-01-01

    Defective cardiac function during sepsis has been referred to as “cardiomyopathy of sepsis.” It is known that sepsis leads to intensive activation of the complement system. In the current study, cardiac function and cardiomyocyte contractility have been evaluated in rats after cecal ligation and puncture (CLP). Significant reductions in left ventricular pressures occurred in vivo and in cardiomyocyte contractility in vitro. These defects were prevented in CLP rats given blocking antibody to C...

  9. Phosphoinositide-3-kinase/akt - dependent signaling is required for maintenance of [Ca2+]i,ICa, and Ca2+ transients in HL-1 cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Graves Bridget M

    2012-06-01

    Full Text Available Abstract The phosphoinositide 3-kinases (PI3K/Akt dependent signaling pathway plays an important role in cardiac function, specifically cardiac contractility. We have reported that sepsis decreases myocardial Akt activation, which correlates with cardiac dysfunction in sepsis. We also reported that preventing sepsis induced changes in myocardial Akt activation ameliorates cardiovascular dysfunction. In this study we investigated the role of PI3K/Akt on cardiomyocyte function by examining the role of PI3K/Akt-dependent signaling on [Ca2+]i, Ca2+ transients and membrane Ca2+ current, ICa, in cultured murine HL-1 cardiomyocytes. LY294002 (1–20 μM, a specific PI3K inhibitor, dramatically decreased HL-1 [Ca2+]i, Ca2+ transients and ICa. We also examined the effect of PI3K isoform specific inhibitors, i.e. α (PI3-kinase α inhibitor 2; 2–8 nM; β (TGX-221; 100 nM and γ (AS-252424; 100 nM, to determine the contribution of specific isoforms to HL-1 [Ca2+]i regulation. Pharmacologic inhibition of each of the individual PI3K isoforms significantly decreased [Ca2+]i, and inhibited Ca2+ transients. Triciribine (1–20 μM, which inhibits AKT downstream of the PI3K pathway, also inhibited [Ca2+]i, and Ca2+ transients and ICa. We conclude that the PI3K/Akt pathway is required for normal maintenance of [Ca2+]i in HL-1 cardiomyocytes. Thus, myocardial PI3K/Akt-PKB signaling sustains [Ca2+]i required for excitation-contraction coupling in cardiomyoctyes.

  10. Azelnidipine prevents cardiac dysfunction in streptozotocin-diabetic rats by reducing intracellular calcium accumulation, oxidative stress and apoptosis

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    Kain Vasundhara

    2011-11-01

    Full Text Available Abstract Background Numerous evidences suggest that diabetic heart is characterized by compromised ventricular contraction and prolonged relaxation attributable to multiple causative factors including calcium accumulation, oxidative stress and apoptosis. Therapeutic interventions to prevent calcium accumulation and oxidative stress could be therefore helpful in improving the cardiac function under diabetic condition. Methods This study was designed to examine the effect of long-acting calcium channel blocker (CCB, Azelnidipine (AZL on contractile dysfunction, intracellular calcium (Ca2+ cycling proteins, stress-activated signaling molecules and apoptosis on cardiomyocytes in diabetes. Adult male Wistar rats were made diabetic by a single intraperitoneal (IP injection of streptozotocin (STZ. Contractile functions were traced from live diabetic rats to isolated individual cardiomyocytes including peak shortening (PS, time-to-PS (TPS, time-to-relengthening (TR90, maximal velocity of shortening/relengthening (± dL/dt and intracellular Ca2+ fluorescence. Results Diabetic heart showed significantly depressed PS, ± dL/dt, prolonged TPS, TR90 and intracellular Ca2+ clearing and showed an elevated resting intracellular Ca2+. AZL itself exhibited little effect on myocyte mechanics but it significantly alleviated STZ-induced myocyte contractile dysfunction. Diabetes increased the levels of superoxide, enhanced expression of the cardiac damage markers like troponin I, p67phox NADPH oxidase subunit, restored the levels of the mitochondrial superoxide dismutase (Mn-SOD, calcium regulatory proteins RyR2 and SERCA2a, and suppressed the levels of the anti-apoptotic Bcl-2 protein. All of these STZ-induced alterations were reconciled by AZL treatment. Conclusion Collectively, the data suggest beneficial effect of AZL in diabetic cardiomyopathy via altering intracellular Ca2+ handling proteins and preventing apoptosis by its antioxidant property.

  11. Evidence Suggesting that the Cardiomyocyte Circadian Clock Modulates Responsiveness of the Heart to Hypertrophic Stimuli in Mice

    OpenAIRE

    Durgan, David J.; Tsai, Ju-Yun; Grenett, Maximiliano H.; Pat, Betty M.; Ratcliffe, William F.; Villegas-Montoya, Carolina; Garvey, Merissa E.; Nagendran, Jeevan; Dyck, Jason R. B.; Bray, Molly S.; Gamble, Karen L.; Gimble, Jeffrey M.; Young, Martin E.

    2011-01-01

    Circadian dyssynchrony of an organism (at the whole body level) with its environment, either through light/dark cycle or genetic manipulation of clock genes, augments various cardiometabolic diseases. The cardiomyocyte circadian clock has recently been shown to influence multiple myocardial processes, ranging from transcriptional regulation and energy metabolism, to contractile function. We therefore reasoned that chronic dyssychrony of the cardiomyocyte circadian clock with its environment w...

  12. Active contractility in actomyosin networks

    CERN Document Server

    Wang, Shenshen

    2012-01-01

    Contractile forces are essential for many developmental processes involving cell shape change and tissue deformation. Recent experiments on reconstituted actomyosin networks, the major component of the contractile machinery, have shown that active contractility occurs above a threshold motor concentration and within a window of crosslink concentration. We present a microscopic dynamic model that incorporates two essential aspects of actomyosin self-organization: the asymmetric load response of individual actin filaments and the correlated motor-driven events mimicking myosin-induced filament sliding. Using computer simulations we examine how the concentration and susceptibility of motors contribute to their collective behavior and interplay with the network connectivity to regulate macroscopic contractility. Our model is shown to capture the formation and dynamics of contractile structures and agree with the observed dependence of active contractility on microscopic parameters including the contractility onse...

  13. Longstanding hyperthyroidism is associated with normal or enhanced intrinsic cardiomyocyte function despite decline in global cardiac function.

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    Nathan Y Weltman

    Full Text Available Thyroid hormones (THs play a pivotal role in cardiac homeostasis. TH imbalances alter cardiac performance and ultimately cause cardiac dysfunction. Although short-term hyperthyroidism typically leads to heightened left ventricular (LV contractility and improved hemodynamic parameters, chronic hyperthyroidism is associated with deleterious cardiac consequences including increased risk of arrhythmia, impaired cardiac reserve and exercise capacity, myocardial remodeling, and occasionally heart failure. To evaluate the long-term consequences of chronic hyperthyroidism on LV remodeling and function, we examined LV isolated myocyte function, chamber function, and whole tissue remodeling in a hamster model. Three-month-old F1b hamsters were randomized to control or 10 months TH treatment (0.1% grade I desiccated TH. LV chamber remodeling and function was assessed by echocardiography at 1, 2, 4, 6, 8, and 10 months of treatment. After 10 months, terminal cardiac function was assessed by echocardiography and LV hemodynamics. Hyperthyroid hamsters exhibited significant cardiac hypertrophy and deleterious cardiac remodeling characterized by myocyte lengthening, chamber dilatation, decreased relative wall thickness, increased wall stress, and increased LV interstitial fibrotic deposition. Importantly, hyperthyroid hamsters demonstrated significant LV systolic and diastolic dysfunction. Despite the aforementioned remodeling and global cardiac decline, individual isolated cardiac myocytes from chronically hyperthyroid hamsters had enhanced function when compared with myocytes from untreated age-matched controls. Thus, it appears that long-term hyperthyroidism may impair global LV function, at least in part by increasing interstitial ventricular fibrosis, in spite of normal or enhanced intrinsic cardiomyocyte function.

  14. Enhancement of cardiomyocyte differentiation from human embryonic stem cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Several approaches have been used to encourage the differentiation of cardiomyocytes from human embryonic stem cells.However,the differentiation efficiency is low,and appropriate culture protocols are needed to produce adequate numbers of cardiomyocytes for therapeutic cell transplantation.This study investigated the effects of serum on cardiomyocyte differentiation in suspension culture medium during embryoid body(EB) formation by human embryonic stem cells.The addition of ascorbic acid,dimethylsulfoxide and 5-aza-2’-deoxycytidine during days 5-7 at the EB-forming stage resulted in an increase in the numbers of rhythmically contracting clusters of derived cardiomyocytes.Treatment with 0.1 mmol L-1 ascorbic acid alone,or more notably in combination with 10 μmol L-1 5-aza-2’-deoxycytidine,induced the formation of beating cells within EBs.Most of the beating clusters had spontaneous contraction rates similar to those found in human adults,and their contractile ac-tivity lasted for up to 194 days.

  15. Cardiac fibroblasts contribute to myocardial dysfunction in mice with sepsis: the role of NLRP3 inflammasome activation.

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    Wenbo Zhang

    Full Text Available Myocardial contractile dysfunction in sepsis is associated with the increased morbidity and mortality. Although the underlying mechanisms of the cardiac depression have not been fully elucidated, an exaggerated inflammatory response is believed to be responsible. Nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3 inflammasome is an intracellular platform that is involved in the maturation and release of interleukin (IL-1β. The aim of the present study is to evaluate whether sepsis activates NLRP3 inflammasome/caspase-1/IL-1β pathway in cardiac fibroblasts (CFs and whether this cytokine can subsequently impact the function of cardiomyocytes (cardiac fibroblast-myocyte cross-talk. We show that treatment of CFs with lipopolysaccharide (LPS induces upregulation of NLRP3, activation of caspase-1, as well as the maturation (activation and release of IL-1β. In addition, the genetic (small interfering ribonucleic acid [siRNA] and pharmacological (glyburide inhibition of the NLRP3 inflammasome in CFs can block this signaling pathway. Furthermore, the inhibition of the NLRP3 inflammasome in cardiac fibroblasts ameliorated the ability of LPS-challenged CFs to impact cardiomyocyte function as assessed by intracellular cyclic adenosine monophosphate (cAMP responses in cardiomyocytes. Salient features of this the NLP3 inflammasome/ caspase-1 pathway were confirmed in in vivo models of endotoxemia/sepsis. We found that inhibition of the NLRP3 inflammasome attenuated myocardial dysfunction in mice with LPS and increased the survival rate in mice with feces-induced peritonitis. Our results indicate that the activation of the NLRP3 inflammasome in cardiac fibroblasts is pivotal in the induction of myocardial dysfunction in sepsis.

  16. Human Engineered Heart Tissue: Analysis of Contractile Force

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    Ingra Mannhardt

    2016-07-01

    Full Text Available Analyzing contractile force, the most important and best understood function of cardiomyocytes in vivo is not established in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM. This study describes the generation of 3D, strip-format, force-generating engineered heart tissues (EHT from hiPSC-CM and their physiological and pharmacological properties. CM were differentiated from hiPSC by a growth factor-based three-stage protocol. EHTs were generated and analyzed histologically and functionally. HiPSC-CM in EHTs showed well-developed sarcomeric organization and alignment, and frequent mitochondria. Systematic contractility analysis (26 concentration-response curves reveals that EHTs replicated canonical response to physiological and pharmacological regulators of inotropy, membrane- and calcium-clock mediators of pacemaking, modulators of ion-channel currents, and proarrhythmic compounds with unprecedented precision. The analysis demonstrates a high degree of similarity between hiPSC-CM in EHT format and native human heart tissue, indicating that human EHTs are useful for preclinical drug testing and disease modeling.

  17. Human Engineered Heart Tissue: Analysis of Contractile Force.

    Science.gov (United States)

    Mannhardt, Ingra; Breckwoldt, Kaja; Letuffe-Brenière, David; Schaaf, Sebastian; Schulz, Herbert; Neuber, Christiane; Benzin, Anika; Werner, Tessa; Eder, Alexandra; Schulze, Thomas; Klampe, Birgit; Christ, Torsten; Hirt, Marc N; Huebner, Norbert; Moretti, Alessandra; Eschenhagen, Thomas; Hansen, Arne

    2016-07-12

    Analyzing contractile force, the most important and best understood function of cardiomyocytes in vivo is not established in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). This study describes the generation of 3D, strip-format, force-generating engineered heart tissues (EHT) from hiPSC-CM and their physiological and pharmacological properties. CM were differentiated from hiPSC by a growth factor-based three-stage protocol. EHTs were generated and analyzed histologically and functionally. HiPSC-CM in EHTs showed well-developed sarcomeric organization and alignment, and frequent mitochondria. Systematic contractility analysis (26 concentration-response curves) reveals that EHTs replicated canonical response to physiological and pharmacological regulators of inotropy, membrane- and calcium-clock mediators of pacemaking, modulators of ion-channel currents, and proarrhythmic compounds with unprecedented precision. The analysis demonstrates a high degree of similarity between hiPSC-CM in EHT format and native human heart tissue, indicating that human EHTs are useful for preclinical drug testing and disease modeling. PMID:27211213

  18. c-kitpos GATA-4 high rat cardiac stem cells foster adult cardiomyocyte survival through IGF-1 paracrine signalling.

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    Nanako Kawaguchi

    Full Text Available BACKGROUND: Resident c-kit positive (c-kitpos cardiac stem cells (CSCs could be considered the most appropriate cell type for myocardial regeneration therapies. However, much is still unknown regarding their biological properties and potential. METHODOLOGY/PRINCIPAL FINDINGS: We produced clones of high and low expressing GATA-4 CSCs from long-term bulk-cultured c-kitpos CSCs isolated from adult rat hearts. When c-kitpos GATA-4 high expressing clonal CSCs (cCSCs were co-cultured with adult rat ventricular cardiomyocytes, we observed increased survival and contractility of the cardiomyocytes, compared to cardiomyocytes cultured alone, co-cultured with fibroblasts or c-kitpos GATA-4 low expressing cCSCs. When analysed by ELISA, the concentration of IGF-1 was significantly increased in the c-kitpos GATA-4 high cCSC/cardiomyocyte co-cultures and there was a significant correlation between IGF-1 concentration and cardiomyocyte survival. We showed the activation of the IGF-1 receptor and its downstream molecular targets in cardiomyocytes co-cultured with c-kitpos GATA-4 high cCSCs but not in cardiomyocytes that were cultured alone, co-cultured with fibroblasts or c-kitpos GATA-4 low cCSCs. Addition of a blocking antibody specific to the IGF-1 receptor inhibited the survival of cardiomyocytes and prevented the activation of its signalling in cardiomyocytes in the c-kitpos GATA-4 high cCSC/cardiomyocyte co-culture system. IGF-1 supplementation or IGF-1 high conditioned medium taken from the co-culture of c-kitpos GATA-4 high cCSCs plus cardiomyocytes did extend the survival and contractility of cardiomyocytes cultured alone and cardiomyocytes co-cultured with c-kitpos GATA-4 low cCSCs. CONCLUSION/SIGNIFICANCE: c-kitpos GATA-4 high cCSCs exert a paracrine survival effect on cardiomyocytes through induction of the IGF-1R and signalling pathway.

  19. Dietary Nitrate and Skeletal Muscle Contractile Function in Heart Failure.

    Science.gov (United States)

    Coggan, Andrew R; Peterson, Linda R

    2016-08-01

    Heart failure (HF) patients suffer from exercise intolerance that diminishes their ability to perform normal activities of daily living and hence compromises their quality of life. This is due largely to detrimental changes in skeletal muscle mass, structure, metabolism, and function. This includes an impairment of muscle contractile performance, i.e., a decline in the maximal force, speed, and power of muscle shortening. Although numerous mechanisms underlie this reduction in contractility, one contributing factor may be a decrease in nitric oxide (NO) bioavailability. Consistent with this, recent data demonstrate that acute ingestion of NO3 (-)-rich beetroot juice, a source of NO via the NO synthase-independent enterosalivary pathway, markedly increases maximal muscle speed and power in HF patients. This review discusses the role of muscle contractile dysfunction in the exercise intolerance characteristic of HF, and the evidence that dietary NO3 (-) supplementation may represent a novel and simple therapy for this currently underappreciated problem. PMID:27271563

  20. Pivotal effects of phosphodiesterase inhibitors on myocyte contractility and viability in normal and ischemic hearts

    Institute of Scientific and Technical Information of China (English)

    Yuan James RAO; Lei XI

    2009-01-01

    Phosphodiesterases (PDEs) are enzymes that degrade cellular cAMP and cGMP and are thus essential for regulating the cyclic nucleotides. At least 11 families of PDEs have been identified, each with a distinctive structure, activity, expression, and tissue distribution. The PDE type-3, -4, and -5 (PDE3, PDE4, PDE5) are localized to specific regions of the cardiomyo-cyte, such as the sarcoplasmic reticulum and Z-disc, where they are likely to influence cAMP/cGMP signaling to the end effectors of contractility. Several PDE inhibitors exhibit remarkable hemodynamic and inotropic properties that may be valuable to clinical practice. In particular, PDE3 inhibitors have potent cardiotonic effects that can be used for short-term inotropic support, especially in situations where adrenergic stimulation is insufficient. Most relevant to this review, PDE in-hibitors have also been found to have cytoprotective effects in the heart. For example, PDE3 inhibitors have been shown to be cardioprotective when given before ischemic attack, whereas PDE5 inhibitors, which include three widely used erectile dysfunction drugs (sildenafil, vardenafil and tadalafil), can induce remarkable cardioprotection when administered either prior to ischemia or upon reperfusion. This article provides an overview of the current laboratory and clinical evidence, as well as the cellular mechanisms by which the inhibitors of PDE3, PDE4 and PDE5 exert their beneficial effects on normal and ischemic hearts. It seems that PDE inhibitors hold great promise as clinically applicable agents that can improve car-diac performance and cell survival under critical situations, such as ischemic heart attack, cardiopulmonary bypass surgery, and heart failure.

  1. Decreased Polycystin 2 Levels Result in Non-Renal Cardiac Dysfunction with Aging.

    Directory of Open Access Journals (Sweden)

    Ivana Y Kuo

    Full Text Available Mutations in the gene for polycystin 2 (Pkd2 lead to polycystic kidney disease, however the main cause of mortality in humans is cardiac related. We previously showed that 5 month old Pkd2+/- mice have altered calcium-contractile activity in cardiomyocytes, but have preserved cardiac function. Here, we examined 1 and 9 month old Pkd2+/- mice to determine if decreased amounts of functional polycystin 2 leads to impaired cardiac function with aging. We observed changes in calcium handling proteins in 1 month old Pkd2+/- mice, and these changes were exacerbated in 9 month old Pkd2+/- mice. Anatomically, the 9 month old Pkd2+/- mice had thinner left ventricular walls, consistent with dilated cardiomyopathy, and the left ventricular ejection fraction was decreased. Intriguingly, in response to acute isoproterenol stimulation to examine β-adrenergic responses, the 9 month old Pkd2+/- mice exhibited a stronger contractile response, which also coincided with preserved localization of the β2 adrenergic receptor. Importantly, the Pkd2+/- mice did not have any renal impairment. We conclude that the cardiac-related impact of decreased polycystin 2 progresses over time towards cardiac dysfunction and altered adrenergic signaling. These results provide further evidence that polycystin 2 provides a critical function in the heart, independent of renal involvement.

  2. Decreased Polycystin 2 Levels Result in Non-Renal Cardiac Dysfunction with Aging.

    Science.gov (United States)

    Kuo, Ivana Y; Duong, Sophie L; Nguyen, Lily; Ehrlich, Barbara E

    2016-01-01

    Mutations in the gene for polycystin 2 (Pkd2) lead to polycystic kidney disease, however the main cause of mortality in humans is cardiac related. We previously showed that 5 month old Pkd2+/- mice have altered calcium-contractile activity in cardiomyocytes, but have preserved cardiac function. Here, we examined 1 and 9 month old Pkd2+/- mice to determine if decreased amounts of functional polycystin 2 leads to impaired cardiac function with aging. We observed changes in calcium handling proteins in 1 month old Pkd2+/- mice, and these changes were exacerbated in 9 month old Pkd2+/- mice. Anatomically, the 9 month old Pkd2+/- mice had thinner left ventricular walls, consistent with dilated cardiomyopathy, and the left ventricular ejection fraction was decreased. Intriguingly, in response to acute isoproterenol stimulation to examine β-adrenergic responses, the 9 month old Pkd2+/- mice exhibited a stronger contractile response, which also coincided with preserved localization of the β2 adrenergic receptor. Importantly, the Pkd2+/- mice did not have any renal impairment. We conclude that the cardiac-related impact of decreased polycystin 2 progresses over time towards cardiac dysfunction and altered adrenergic signaling. These results provide further evidence that polycystin 2 provides a critical function in the heart, independent of renal involvement. PMID:27081851

  3. Effect of biophysical cues on reprogramming to cardiomyocytes.

    Science.gov (United States)

    Sia, Junren; Yu, Pengzhi; Srivastava, Deepak; Li, Song

    2016-10-01

    Reprogramming of fibroblasts to cardiomyocytes offers exciting potential in cell therapy and regenerative medicine, but has low efficiency. We hypothesize that physical cues may positively affect the reprogramming process, and studied the effects of periodic mechanical stretch, substrate stiffness and microgrooved substrate on reprogramming yield. Subjecting reprogramming fibroblasts to periodic mechanical stretch and different substrate stiffness did not improve reprogramming yield. On the other hand, culturing the cells on microgrooved substrate enhanced the expression of cardiomyocyte genes by day 2 and improved the yield of partially reprogrammed cells at day 10. By combining microgrooved substrate with an existing optimized culture protocol, yield of reprogrammed cardiomyocytes with striated cardiac troponin T staining and spontaneous contractile activity was increased. We identified the regulation of Mkl1 activity as a new mechanism by which microgroove can affect reprogramming. Biochemical approach could only partially recapitulate the effect of microgroove. Microgroove demonstrated an additional effect of enhancing organization of sarcomeric structure, which could not be recapitulated by biochemical approach. This study provides insights into new mechanisms by which topographical cues can affect cellular reprogramming.

  4. THE CIRCADIAN CLOCK WITHIN THE CARDIOMYOCYTE IS ESSENTIAL FOR RESPONSIVENESS OF THE HEART TO FATTY ACIDS

    Science.gov (United States)

    Cells/organs must respond both rapidly and appropriately to increased fatty acid availability; failure to do so is associated with the development of skeletal muscle and hepatic insulin resistance, pancreatic beta-cell dysfunction, and myocardial contractile dysfunction. Here we tested the hypothesi...

  5. Generation of Functional Cardiomyocytes from the Synoviocytes of Patients with Rheumatoid Arthritis via Induced Pluripotent Stem Cells

    Science.gov (United States)

    Lee, Jaecheol; Jung, Seung Min; Ebert, Antje D.; Wu, Haodi; Diecke, Sebastian; Kim, Youngkyun; Yi, Hyoju; Park, Sung-Hwan; Ju, Ji Hyeon

    2016-09-01

    Cardiovascular disease is a leading cause of morbidity in rheumatoid arthritis (RA) patients. This study aimed to generate and characterise cardiomyocytes from induced pluripotent stem cells (iPSCs) of RA patients. Fibroblast-like synoviocytes (FLSs) from patients with RA and osteoarthritis (OA) were successfully reprogrammed into RA-iPSCs and OA-iPSCs, respectively. The pluripotency of iPSCs was confirmed by quantitative reverse transcription-polymerase chain reaction and immunofluorescence staining. Established iPSCs were differentiated into cardiomyocytes using a small molecule-based monolayer differentiation protocol. Within 12 days of cardiac differentiation from patient-specific and control-iPSCs, spontaneously beating cardiomyocytes (iPSC-CMs) were observed. All iPSC-CMs exhibited a reliable sarcomeric structure stained with antibodies against cardiac markers and similar expression profiles of cardiac-specific genes. Intracellular calcium signalling was recorded to compare calcium-handling properties among cardiomyocytes differentiated from the three groups of iPSCs. RA-iPSC-CMs had a lower amplitude and a shorter duration of calcium transients than the control groups. Peak tangential stress and the maximum contractile rate were also decreased in RA-iPSC-CMs, suggesting that contractility was reduced. This study demonstrates the successful generation of functional cardiomyocytes from pathogenic synovial cells in RA patients through iPSC reprogramming. Research using RA-iPSC-CMs might provide an opportunity to investigate the pathophysiology of cardiac involvement in RA.

  6. Generation of Functional Cardiomyocytes from the Synoviocytes of Patients with Rheumatoid Arthritis via Induced Pluripotent Stem Cells

    Science.gov (United States)

    Lee, Jaecheol; Jung, Seung Min; Ebert, Antje D.; Wu, Haodi; Diecke, Sebastian; Kim, Youngkyun; Yi, Hyoju; Park, Sung-Hwan; Ju, Ji Hyeon

    2016-01-01

    Cardiovascular disease is a leading cause of morbidity in rheumatoid arthritis (RA) patients. This study aimed to generate and characterise cardiomyocytes from induced pluripotent stem cells (iPSCs) of RA patients. Fibroblast-like synoviocytes (FLSs) from patients with RA and osteoarthritis (OA) were successfully reprogrammed into RA-iPSCs and OA-iPSCs, respectively. The pluripotency of iPSCs was confirmed by quantitative reverse transcription-polymerase chain reaction and immunofluorescence staining. Established iPSCs were differentiated into cardiomyocytes using a small molecule-based monolayer differentiation protocol. Within 12 days of cardiac differentiation from patient-specific and control-iPSCs, spontaneously beating cardiomyocytes (iPSC-CMs) were observed. All iPSC-CMs exhibited a reliable sarcomeric structure stained with antibodies against cardiac markers and similar expression profiles of cardiac-specific genes. Intracellular calcium signalling was recorded to compare calcium-handling properties among cardiomyocytes differentiated from the three groups of iPSCs. RA-iPSC-CMs had a lower amplitude and a shorter duration of calcium transients than the control groups. Peak tangential stress and the maximum contractile rate were also decreased in RA-iPSC-CMs, suggesting that contractility was reduced. This study demonstrates the successful generation of functional cardiomyocytes from pathogenic synovial cells in RA patients through iPSC reprogramming. Research using RA-iPSC-CMs might provide an opportunity to investigate the pathophysiology of cardiac involvement in RA. PMID:27609119

  7. Modeling Fatty Acid Transfer from Artery to Cardiomyocyte.

    Science.gov (United States)

    Arts, Theo; Reneman, Robert S; Bassingthwaighte, James B; van der Vusse, Ger J

    2015-12-01

    Despite the importance of oxidation of blood-borne long-chain fatty acids (Fa) in the cardiomyocytes for contractile energy of the heart, the mechanisms underlying the transfer of Fa from the coronary plasma to the cardiomyocyte is still incompletely understood. To obtain detailed insight into this transfer process, we designed a novel model of Fa transfer dynamics from coronary plasma through the endothelial cells and interstitium to the cardiomyocyte, applying standard physicochemical principles on diffusion and on the chemical equilibrium of Fa binding to carrier proteins Cp, like albumin in plasma and interstitium and Fatty Acid-Binding Proteins within endothelium and cardiomyocytes. Applying these principles, the present model strongly suggests that in the heart, binding and release of Fa to and from Cp in the aqueous border zones on both sides of the cell membranes form the major hindrance to Fa transfer. Although often considered, the membrane itself appears not to be a significant hindrance to diffusion of Fa. Proteins, residing in the cellular membrane, may facilitate transfer of Fa between Cp and membrane. The model is suited to simulate multiple tracer dilution experiments performed on isolated rabbit hearts administrating albumin and Fa as tracer substances into the coronary arterial perfusion line. Using parameter values on myocardial ultrastructure and physicochemical properties of Fa and Cp as reported in literature, simulated washout curves appear to be similar to the experimentally determined ones. We conclude therefore that the model is realistic and, hence, can be considered as a useful tool to better understand Fa transfer by evaluation of experimentally determined tracer washout curves.

  8. Modeling Fatty Acid Transfer from Artery to Cardiomyocyte.

    Directory of Open Access Journals (Sweden)

    Theo Arts

    2015-12-01

    Full Text Available Despite the importance of oxidation of blood-borne long-chain fatty acids (Fa in the cardiomyocytes for contractile energy of the heart, the mechanisms underlying the transfer of Fa from the coronary plasma to the cardiomyocyte is still incompletely understood. To obtain detailed insight into this transfer process, we designed a novel model of Fa transfer dynamics from coronary plasma through the endothelial cells and interstitium to the cardiomyocyte, applying standard physicochemical principles on diffusion and on the chemical equilibrium of Fa binding to carrier proteins Cp, like albumin in plasma and interstitium and Fatty Acid-Binding Proteins within endothelium and cardiomyocytes. Applying these principles, the present model strongly suggests that in the heart, binding and release of Fa to and from Cp in the aqueous border zones on both sides of the cell membranes form the major hindrance to Fa transfer. Although often considered, the membrane itself appears not to be a significant hindrance to diffusion of Fa. Proteins, residing in the cellular membrane, may facilitate transfer of Fa between Cp and membrane. The model is suited to simulate multiple tracer dilution experiments performed on isolated rabbit hearts administrating albumin and Fa as tracer substances into the coronary arterial perfusion line. Using parameter values on myocardial ultrastructure and physicochemical properties of Fa and Cp as reported in literature, simulated washout curves appear to be similar to the experimentally determined ones. We conclude therefore that the model is realistic and, hence, can be considered as a useful tool to better understand Fa transfer by evaluation of experimentally determined tracer washout curves.

  9. A micro-spherical heart pump powered by cultured cardiomyocytes.

    Science.gov (United States)

    Tanaka, Yo; Sato, Kae; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo; Kitamori, Takehiko

    2007-02-01

    Miniaturization of chemical or biochemical systems creates extremely efficient devices exploiting the advantages of microspaces. Although they are often targeted for implanted tissue engineered organs or drug-delivery devices because of their highly integrated systems, microfluidic devices are usually powered by external energy sources and therefore difficult to be used in vivo. A microfluidic device powered without the need for external energy sources or stimuli is needed. Previously, we demonstrated the concept of a cardiomyocyte pump using only chemical energy input to cells as a driver (Yo Tanaka, Keisuke Morishima, Tatsuya Shimizu, Akihiko Kikuchi, Masayuki Yamato, Teruo Okano and Takehiko Kitamori, Lab Chip, 6(3), pp. 362-368). However, the structure of this prototype pump described there included complicated mechanical components and fabricated compartments. Here, we have created a micro-spherical heart-like pump powered by spontaneously contracting cardiomyocyte sheets driven without a need for external energy sources or coupled stimuli. This device was fabricated by wrapping a beating cardiomyocyte sheet exhibiting large contractile forces around a fabricated hollow elastomeric sphere (5 mm diameter, 250 microm polymer thickness) fixed with inlet and outlet ports. Fluid oscillations in a capillary connected to the hollow sphere induced by the synchronously pulsating cardiomyocyte sheet were confirmed, and the device continually worked for at least 5 days in this system. This bio/artificial hybrid fluidic pump device is innovative not only because it is driven by cells using only chemical energy input, but also because the design is an optimum structure (sphere). We anticipate that this device might be applied for various purposes including a bio-actuator for medical implant devices that relies on biochemical energy, not electrical interfacing. PMID:17268623

  10. Impact of mitochondria on nitrite metabolism in HL-1 cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Peter eDungel

    2013-05-01

    Full Text Available Apart from ATP synthesis mitochondria have many other functions, one being nitrite reductase activity. NO released from nitrite has been shown to protect the heart from ischemia/reperfusion injury in a cGMP-dependent manner. However, the exact impact of mitochondria on the release of NO from nitrite in cardiomyocytes is not completely understood. Besides mitochondria, a number of non-mitochondrial metalloproteins have been suggested to facilitate this process. The aim of this study was to investigate the impact of mitochondria on the bioactivation of nitrite in HL-1 cardiomyocytes.The levels of nitrosyl complexes of hemoglobin (NO-Hb and cGMP levels were measured by electron spin resonance spectroscopy and enzyme immunoassay. In addition the formation of free NO was determined by confocal microscopy as well as intracellular nitrite and S-nitrosothiols by chemoluminescence analysis. NO was released from nitrite in cell culture in an oxygen dependent manner. Application of specific inhibitors of the respiratory chain, p450, NO synthases and xanthine oxidoreductase showed that all four enzymatic systems are involved in the release of NO, but more than 50% of NO is released via the mitochondrial pathway. Only NO released by mitochondria activated cGMP synthesis. Cardiomyocytes co-cultured with red blood cells (RBC competed with RBC for nitrite, but free NO was detected only in HL-1 cells suggesting that RBC are not a source of NO in this model. Apart from activation of cGMP synthesis, NO formed in HL-1 cells diffused out of the cells and formed NO-Hb complexes. In addition nitrite was converted by HL-1 cells to S-nitrosyl complexes. In HL-1 cardiomyocytes, several enzymatic systems are involved in nitrite reduction to NO but only the mitochondrial pathway of NO release activates cGMP synthesis. Our data suggest that this pathway may be a key regulator of myocardial contractility especially under hypoxic conditions.

  11. Structural comparison of contractile nanomachines

    Directory of Open Access Journals (Sweden)

    Sebastian Kube

    2015-05-01

    Full Text Available Contractile molecular machines are a common feature among bacteriophages and prokaryotes. Due to their stability and the large size, contractile-tailed bacteriophages are traditionally investigated by electron microscopic methods. Complemented by crystallographic studies, a molecular model of contraction for the T4 phage was developed. Lately, also related contractile structures like the Photorhabdus virulence cassette-like particles, the R-Type pyocins and the contractile tubule of the bacterial Type VI secretion system have been analyzed by cryo electron microscopy. Photorhabdus virulence cassette particles and R-Type pyocins are toxin complexes reminiscent of bacteriophage tails that are secreted by bacteria to kill their insect host or competing bacteria. In contrast, the Type VI secretion system is an intracellular apparatus for injection of effector proteins into bacterial and eukaryotic cells. Although it shares homology with other contractile systems, the Type VI secretion system is additionally equipped with a recycling function, which makes it suitable for multiple rounds of action. Starting from the 3D reconstructions, we compare these molecular machines structurally and functionally to their viral counterparts and summarize the current knowledge on their respective mode of action.

  12. Electrically contractile polymers augment right ventricular output in the heart.

    Science.gov (United States)

    Ruhparwar, Arjang; Piontek, Patricia; Ungerer, Matthias; Ghodsizad, Ali; Partovi, Sasan; Foroughi, Javad; Szabo, Gabor; Farag, Mina; Karck, Matthias; Spinks, Geoffrey M; Kim, Seon Jeong

    2014-12-01

    Research into the development of artificial heart muscle has been limited to assembly of stem cell-derived cardiomyocytes seeded around a matrix, while nonbiological approaches to tissue engineering have rarely been explored. The aim of the study was to apply electrically contractile polymer-based actuators as cardiomyoplasty for positive inotropic support of the right ventricle. Complex trilayer polypyrrole (PPy) bending polymers for high-speed applications were generated. Bending motion occurred directly as a result of electrochemically driven charging and discharging of the PPy layers. In a rat model (n = 5), strips of polymers (3 × 20 mm) were attached and wrapped around the right ventricle (RV). RV pressure was continuously monitored invasively by direct RV cannulation. Electrical activation occurred simultaneously with either diastole (in order to evaluate the polymer's stand-alone contraction capacity; group 1) or systole (group 2). In group 1, the pressure generation capacity of the polymers was measured by determining the area under the pressure curve (area under curve, AUC). In group 2, the RV pressure AUC was measured in complexes directly preceding those with polymer contraction and compared to RV pressure complexes with simultaneous polymer contraction. In group 1, the AUC generated by polymer contraction was 2768 ± 875 U. In group 2, concomitant polymer contraction significantly increased AUC compared with complexes without polymer support (5987 ± 1334 U vs. 4318 ± 691 U, P ≤ 0.01). Electrically contractile polymers are able to significantly augment right ventricular contraction. This approach may open new perspectives for myocardial tissue engineering, possibly in combination with fetal or embryonic stem cell-derived cardiomyocytes.

  13. Regulation of Akt/PKB activity by P21-activated kinase in cardiomyocytes.

    Science.gov (United States)

    Mao, Kai; Kobayashi, Satoru; Jaffer, Zahara M; Huang, Yuan; Volden, Paul; Chernoff, Jonathan; Liang, Qiangrong

    2008-02-01

    Akt/PKB is a critical regulator of cardiac function and morphology, and its activity is governed by dual phosphorylation at active loop (Thr308) by phosphoinositide-dependent protein kinase-1 (PDK1) and at carboxyl-terminal hydrophobic motif (Ser473) by a putative PDK2. P21-activated kinase-1 (Pak1) is a serine/threonine protein kinase implicated in the regulation of cardiac hypertrophy and contractility and was shown previously to activate Akt through an undefined mechanism. Here we report Pak1 as a potential PDK2 that is essential for Akt activity in cardiomyocytes. Both Pak1 and Akt can be activated by multiple hypertrophic stimuli or growth factors in a phosphatidylinositol-3-kinase (PI3K)-dependent manner. Pak1 overexpression induces Akt phosphorylation at both Ser473 and Thr308 in cardiomyocytes. Conversely, silencing or inactivating Pak1 gene diminishes Akt phosphorylation in vitro and in vivo. Purified Pak1 can directly phosphorylate Akt only at Ser473, suggesting that Pak1 may be a relevant PDK2 responsible for AKT Ser473 phosphorylation in cardiomyocytes. In addition, Pak1 protects cardiomyocytes from cell death, which is blocked by Akt inhibition. Our results connect two important regulators of cellular physiological functions and provide a potential mechanism for Pak1 signaling in cardiomyocytes. PMID:18054038

  14. Intrinsic-mediated caspase activation is essential for cardiomyocyte hypertrophy

    OpenAIRE

    Putinski, Charis; ABDUL-GHANI, MOHAMMAD; Stiles, Rebecca; Brunette, Steve; Dick, Sarah A.; Fernando, Pasan; Lynn A. Megeney

    2013-01-01

    Cardiac hypertrophy is a pathologic enlargement of the heart, an alteration that leads to contractile dysfunction and eventual organ failure. The hypertrophy phenotype originates from concentric growth of heart muscle cells and shares many biochemical features with programmed cell death, implying a common molecular origin. Here, we show cell-autonomous activation of a mitochondrial cell death pathway during initial stages of muscle cell hypertrophy, a signal that is essential and sufficient t...

  15. Maintenance of HL-1 cardiomyocyte functional activity in PEGylated fibrin gels.

    Science.gov (United States)

    Geuss, Laura R; Allen, Alicia C B; Ramamoorthy, Divya; Suggs, Laura J

    2015-07-01

    Successful cellular cardiomyoplasty is dependent on biocompatible materials that can retain the cells in the myocardium in order to promote host tissue repair following myocardial infarction. A variety of methods have been explored for incorporating a cell-seeded matrix into the heart, the most popular options being direct application of an injectable system or surgical implantation of a patch. Fibrin-based gels are suitable for either of these approaches, as they are biocompatible and have mechanical properties that can be tailored by adjusting the initial fibrinogen concentration. We have previously demonstrated that conjugating amine-reactive homo-bifunctional polyethylene glycol (PEG) to the fibrinogen prior to crosslinking with thrombin can increase stability both in vivo and in vitro. Similarly, when mesenchymal stem cells are combined with PEGylated fibrin and injected into the myocardium, cell retention can be significantly increased and scar tissue reduced following myocardial infarction. We hypothesized that this gel system could similarly promote cardiomyocyte viability and function in vitro, and that optimizing the mechanical properties of the hydrogel would enhance contractility. In this study, we cultured HL-1 cardiomyocytes either on top of plated PEGylated fibrin (2D) or embedded in 3D gels and evaluated cardiomyocyte function by assessing the expression of cardiomyocyte specific markers, sarcomeric α-actin, and connexin 43, as well as contractile activity. We observed that the culture method can drastically affect the functional phenotype of HL-1 cardiomyocytes, and we present data suggesting the potential use of PEGylated fibrin gel layers to prepare a sheet-like construct for myocardial regeneration. PMID:25657056

  16. Sarcomeric dysfunction contributes to muscle weakness in facioscapulohumeral muscular dystrophy

    NARCIS (Netherlands)

    Lassche, S.; Stienen, G.J.; Irving, T.C.; Maarel, S.M. van der; Voermans, N.C.; Padberg, G.W.A.M.; Granzier, H.; Engelen, B.G. van; Ottenheijm, C.A.C.

    2013-01-01

    OBJECTIVE: To investigate whether sarcomeric dysfunction contributes to muscle weakness in facioscapulohumeral muscular dystrophy (FSHD). METHODS: Sarcomeric function was evaluated by contractile studies on demembranated single muscle fibers obtained from quadriceps muscle biopsies of 4 patients wit

  17. Brief Report: Oxidative Stress Mediates Cardiomyocyte Apoptosis in a Human Model of Danon Disease and Heart Failure

    OpenAIRE

    Hashem, Sherin I.; Perry, Cynthia N.; Bauer, Matthieu; Han, Sangyoon; Clegg, Stacey D.; Ouyang, Kunfu; Deacon, Dekker C.; Spinharney, Mary; Panopoulos, Athanasia D.; Belmonte, Juan Carlos Izpisua; Frazer, Kelly A; Chen, Ju; Gong, Qiuming; Zhou, Zhengfeng; Chi, Neil C.

    2015-01-01

    Danon disease is a familial cardiomyopathy associated with impaired autophagy due to mutations in the gene encoding lysosomal-associated membrane protein type 2 (LAMP-2). Emerging evidence has highlighted the importance of autophagy in regulating cardiomyocyte bioenergetics, function, and survival. However, the mechanisms responsible for cellular dysfunction and death in cardiomyocytes with impaired autophagic flux remain unclear. To investigate the molecular mechanisms responsible for Danon ...

  18. Altered calcium handling and increased contraction force in human embryonic stem cell derived cardiomyocytes following short term dexamethasone exposure.

    Science.gov (United States)

    Kosmidis, Georgios; Bellin, Milena; Ribeiro, Marcelo C; van Meer, Berend; Ward-van Oostwaard, Dorien; Passier, Robert; Tertoolen, Leon G J; Mummery, Christine L; Casini, Simona

    2015-11-27

    One limitation in using human pluripotent stem cell derived cardiomyocytes (hPSC-CMs) for disease modeling and cardiac safety pharmacology is their immature functional phenotype compared with adult cardiomyocytes. Here, we report that treatment of human embryonic stem cell derived cardiomyocytes (hESC-CMs) with dexamethasone, a synthetic glucocorticoid, activated glucocorticoid signaling which in turn improved their calcium handling properties and contractility. L-type calcium current and action potential properties were not affected by dexamethasone but significantly faster calcium decay, increased forces of contraction and sarcomeric lengths, were observed in hESC-CMs after dexamethasone exposure. Activating the glucocorticoid pathway can thus contribute to mediating hPSC-CMs maturation.

  19. Prolonged ischemic heart disease and coronary artery bypass - relation to contractile reserve

    DEFF Research Database (Denmark)

    Kofoed, Klaus F; Bangsgaard, Regitze; Carstensen, Steen;

    2002-01-01

    OBJECTIVE: A major effect of coronary artery bypass grafting (CABG) in patients with ischemic heart disease and impaired left ventricular (LV) contractile function is believed to be an improvement in LV function due to recovery of dysfunctional, but viable myocardium. However, recent studies have...

  20. A photopolymerizable hydrogel for 3-D culture of human embryonic stem cell-derived cardiomyocytes and rat neonatal cardiac cells.

    Science.gov (United States)

    Shapira-Schweitzer, Keren; Habib, Manhal; Gepstein, Lior; Seliktar, Dror

    2009-02-01

    The purpose of this study was to assess the in vitro ability of two types of cardiomyocytes (cardiomyocytes derived from human embryonic stem cells (hESC-CM) and rat neonatal cardiomyocytes (rN-CM)) to survive and generate a functional cardiac syncytium in a three-dimensional in situ polymerizable hydrogel environment. Each cell type was cultured in a PEGylated fibrinogen (PF) hydrogel for up to two weeks while maturation and cardiac function were documented in terms of spontaneous contractile behavior and biomolecular organization. Quantitative contractile parameters including contraction amplitude and synchronization were measured by non-invasive image analysis. The rN-CM demonstrated the fastest maturation and the most significant spontaneous contraction. The hESC-CM maturation occurred between 10-14 days in culture, and exhibited less contraction amplitude and synchronization in comparison to the rN-CMs. The maturation of both cell types within the hydrogels was confirmed by cardiac-specific biomolecular markers, including alpha-sarcomeric actin, actinin, and connexin-43. Cellular responsiveness to isoproterenol, carbamylcholine and heptanol provided further evidence of the cardiac maturation in the 3-D PF hydrogel as well as identified a potential to use this system for in vitro drug screening. These findings indicate that the PF hydrogel biomaterial can be used as an in situ polymerizable biomaterial for stem cells and their cardiomyocyte derivatives. PMID:19027751

  1. Tuning the conductivity and inner structure of electrospun fibers to promote cardiomyocyte elongation and synchronous beating.

    Science.gov (United States)

    Liu, Yaowen; Lu, Jinfu; Xu, Guisen; Wei, Jiaojun; Zhang, Zhibin; Li, Xiaohong

    2016-12-01

    The key to addressing the challenges facing cardiac tissue engineering is the integration of physical, chemical, and electrical cues into scaffolds. Aligned and conductive scaffolds have been fabricated as synthetic microenvironments to improve the function of cardiomyocytes. However, up to now, the influence of conductive capability and inner structure of fibrous scaffolds have not been determined on the cardiomyocyte morphologies and beating patterns. In the current study, highly aligned fibers were fabricated with loaded up to 6% of carbon nanotubes (CNTs) to modulate the electrical conductivity, while blend and coaxial electrospinning were utilized to create a bulk distribution of CNTs in fiber matrices and a spatial embedment in fiber cores, respectively. Conductive networks were formed in the fibrous scaffolds after the inoculation of over 3% CNTs, and the increase in the conductivity could maintain the cell viabilities, induce the cell elongation, enhance the production of sarcomeric α-actinin and troponin I, and promote the synchronous beating of cardiomyocytes. Although the conductivity of blend fibers is slightly higher than that of coaxial fibers with the same CNT loadings, the lower exposures to CNTs resulted in higher cell viability, elongation, extracellular matrix secretion and beating rates for cardiomyocytes on coaxial fibers. Taken altogether, core-sheath fibers with loaded 5% of CNTs in the fiber cores facilitated the cardiomyocyte growth with a production of organized contractile proteins and a pulsation frequency close to that of the atrium. It is suggested that electrospun scaffolds that couple conductivity and fibrous structure considerations may provide optimal stimuli to foster cell morphology and functions for myocardial regeneration or establishment of in vitro cardiomyocyte culture platform for drug screening.

  2. Impact of stirred suspension bioreactor culture on the differentiation of murine embryonic stem cells into cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Shafa Mehdi

    2011-12-01

    Full Text Available Abstract Background Embryonic stem cells (ESCs can proliferate endlessly and are able to differentiate into all cell lineages that make up the adult organism. Under particular in vitro culture conditions, ESCs can be expanded and induced to differentiate into cardiomyocytes in stirred suspension bioreactors (SSBs. However, in using these systems we must be cognizant of the mechanical forces acting upon the cells. The effect of mechanical forces and shear stress on ESC pluripotency and differentiation has yet to be clarified. The purpose of this study was to investigate the impact of the suspension culture environment on ESC pluripotency during cardiomyocyte differentiation. Results Murine D3-MHC-neor ESCs formed embyroid bodies (EBs and differentiated into cardiomyocytes over 25 days in static culture and suspension bioreactors. G418 (Geneticin was used in both systems from day 10 to enrich for cardiomyocytes by eliminating non-resistant, undifferentiated cells. Treatment of EBs with 1 mM ascorbic acid and 0.5% dimethyl sulfoxide from day 3 markedly increased the number of beating EBs, which displayed spontaneous and cadenced contractile beating on day 11 in the bioreactor. Our results showed that the bioreactor differentiated cells displayed the characteristics of fully functional cardiomyocytes. Remarkably, however, our results demonstrated that the bioreactor differentiated ESCs retained their ability to express pluripotency markers, to form ESC-like colonies, and to generate teratomas upon transplantation, whereas the cells differentiated in adherent culture lost these characteristics. Conclusions This study demonstrates that although cardiomyocyte differentiation can be achieved in stirred suspension bioreactors, the addition of medium enhancers is not adequate to force complete differentiation as fluid shear forces appear to maintain a subpopulation of cells in a transient pluripotent state. The development of successful ESC

  3. Fructose modulates cardiomyocyte excitation-contraction coupling and Ca²⁺ handling in vitro.

    Directory of Open Access Journals (Sweden)

    Kimberley M Mellor

    Full Text Available BACKGROUND: High dietary fructose has structural and metabolic cardiac impact, but the potential for fructose to exert direct myocardial action is uncertain. Cardiomyocyte functional responsiveness to fructose, and capacity to transport fructose has not been previously demonstrated. OBJECTIVE: The aim of the present study was to seek evidence of fructose-induced modulation of cardiomyocyte excitation-contraction coupling in an acute, in vitro setting. METHODS AND RESULTS: The functional effects of fructose on isolated adult rat cardiomyocyte contractility and Ca²⁺ handling were evaluated under physiological conditions (37°C, 2 mM Ca²⁺, HEPES buffer, 4 Hz stimulation using video edge detection and microfluorimetry (Fura2 methods. Compared with control glucose (11 mM superfusate, 2-deoxyglucose (2 DG, 11 mM substitution prolonged both the contraction and relaxation phases of the twitch (by 16 and 36% respectively, p<0.05 and this effect was completely abrogated with fructose supplementation (11 mM. Similarly, fructose prevented the Ca²⁺ transient delay induced by exposure to 2 DG (time to peak Ca²⁺ transient: 2 DG: 29.0±2.1 ms vs. glucose: 23.6±1.1 ms vs. fructose +2 DG: 23.7±1.0 ms; p<0.05. The presence of the fructose transporter, GLUT5 (Slc2a5 was demonstrated in ventricular cardiomyocytes using real time RT-PCR and this was confirmed by conventional RT-PCR. CONCLUSION: This is the first demonstration of an acute influence of fructose on cardiomyocyte excitation-contraction coupling. The findings indicate cardiomyocyte capacity to transport and functionally utilize exogenously supplied fructose. This study provides the impetus for future research directed towards characterizing myocardial fructose metabolism and understanding how long term high fructose intake may contribute to modulating cardiac function.

  4. Cardiomyocyte Overexpression of FABP4 Aggravates Pressure Overload-Induced Heart Hypertrophy.

    Science.gov (United States)

    Zhang, Ji; Qiao, Congzhen; Chang, Lin; Guo, Yanhong; Fan, Yanbo; Villacorta, Luis; Chen, Y Eugene; Zhang, Jifeng

    2016-01-01

    Fatty acid binding protein 4 (FABP4) is a member of the intracellular lipid-binding protein family, responsible for the transportation of fatty acids. It is considered to express mainly in adipose tissues, and be strongly associated with inflammation, obesity, diabetes and cardiovasculardiseases. Here we report that FABP4 is also expressed in cardiomyocytes and plays an important role in regulating heart function under pressure overload. We generated heart-specific transgenic FABP4 (FABP4-TG) mice using α myosin-heavy chain (α-MHC) promoter and human FABP4 sequence, resulting in over-expression of FABP4 in cardiomyocytes. The FABP4-TG mice displayed normal cardiac morphology and contractile function. When they were subjected to the transverse aorta constriction (TAC) procedure, the FABP4-TG mice developed more cardiac hypertrophy correlated with significantly increased ERK phosphorylation, compared with wild type controls. FABP4 over-expression in cardiomyocytes activated phosphor-ERK signal and up-regulate the expression of cardiac hypertrophic marker genes. Conversely, FABP4 induced phosphor-ERK signal and hypertrophic gene expressions can be markedly inhibited by an ERK inhibitor PD098059 as well as the FABP4 inhibitor BMS309403. These results suggest that FABP4 over-expression in cardiomyocytes can aggravate the development of cardiac hypertrophy through the activation of ERK signal pathway. PMID:27294862

  5. Cardiomyocyte Overexpression of FABP4 Aggravates Pressure Overload-Induced Heart Hypertrophy.

    Directory of Open Access Journals (Sweden)

    Ji Zhang

    Full Text Available Fatty acid binding protein 4 (FABP4 is a member of the intracellular lipid-binding protein family, responsible for the transportation of fatty acids. It is considered to express mainly in adipose tissues, and be strongly associated with inflammation, obesity, diabetes and cardiovasculardiseases. Here we report that FABP4 is also expressed in cardiomyocytes and plays an important role in regulating heart function under pressure overload. We generated heart-specific transgenic FABP4 (FABP4-TG mice using α myosin-heavy chain (α-MHC promoter and human FABP4 sequence, resulting in over-expression of FABP4 in cardiomyocytes. The FABP4-TG mice displayed normal cardiac morphology and contractile function. When they were subjected to the transverse aorta constriction (TAC procedure, the FABP4-TG mice developed more cardiac hypertrophy correlated with significantly increased ERK phosphorylation, compared with wild type controls. FABP4 over-expression in cardiomyocytes activated phosphor-ERK signal and up-regulate the expression of cardiac hypertrophic marker genes. Conversely, FABP4 induced phosphor-ERK signal and hypertrophic gene expressions can be markedly inhibited by an ERK inhibitor PD098059 as well as the FABP4 inhibitor BMS309403. These results suggest that FABP4 over-expression in cardiomyocytes can aggravate the development of cardiac hypertrophy through the activation of ERK signal pathway.

  6. GLP1 protects cardiomyocytes from palmitate-induced apoptosis via Akt/GSK3b/b-catenin pathway.

    Science.gov (United States)

    Ying, Ying; Zhu, Huazhang; Liang, Zhen; Ma, Xiaosong; Li, Shiwei

    2015-12-01

    Activation of apoptosis in cardiomyocytes by saturated palmitic acids contributes to cardiac dysfunction in diabetic cardiomyopathy. Beta-catenin (b-catenin) is a transcriptional regulator of several genes involved in survival/anti-apoptosis. However, its role in palmitate-induced cardiomyocyte apoptosis remains unclear. Glucagon-like peptide 1 (GLP1) has been shown to exhibit potential cardioprotective properties. This study was designed to evaluate the role of b-catenin signalling in palmitate-induced cardiomyocyte apoptosis and the molecular mechanism underlying the protective effects of GLP1 on palmitate-stressed cardiomyocytes. Exposure of neonatal rat cardiomyocytes to palmitate increased the fatty acid transporter CD36-mediated intracellular lipid accumulation and cardiomyocyte apoptosis, decreased accumulation and nuclear translocation of active b-catenin, and reduced expression of b-catenin target protein survivin and BCL2. These detrimental effects of palmitate were significantly attenuated by GLP1 co-treatment. However, the anti-apoptotic effects of GLP1 were markedly abolished when b-catenin was silenced with a specific short hairpin RNA. Furthermore, analysis of the upstream molecules and mechanisms responsible for GLP1-associated cardiac protection revealed that GLP1 restored the decreased phosphorylation of protein kinase B (Akt) and glycogen synthase kinase-3b (GSK3b) in palmitate-stimulated cardiomyocytes. In contrast, inhibition of Akt with an Akt-specific inhibitor MK2206 or blockade of GLP1 receptor (GLP1R) with a competitive antagonist exendin-(9-39) significantly abrogated the GLP1-mediated activation of GSK3b/b-catenin signalling, leading to increased apoptosis in palmitate-stressed cardiomyocytes. Collectively, our results demonstrated for the first time that the attenuated b-catenin signalling may contribute to palmitate-induced cardiomyocyte apoptosis, while GLP1 can protect cardiomyocytes from palmitate-induced apoptosis through

  7. Monitoring Changes in the Redox State of Myoglobin in Cardiomyocytes by Raman Spectroscopy Enables the Protective Effect of NO Donors to Be Evaluated.

    Science.gov (United States)

    Almohammedi, Abdullah; Kapetanaki, Sofia M; Hudson, Andrew J; Storey, Nina M

    2015-10-20

    Raman microspectroscopy has been used to monitor changes in the redox and ligand-coordination states of the heme complex in myoglobin during the preconditioning of ex vivo cardiomyocytes with pharmacological drugs that release nitric oxide (NO). These chemical agents are known to confer protection on heart tissue against ischemia-reperfusion injury. Subsequent changes in the redox and ligand-coordination states during experimental simulations of ischemia and reperfusion have also been monitored. We found that these measurements, in real time, could be used to evaluate the preconditioning treatment of cardiomyocytes and to predict the likelihood of cell survival following a potentially lethal period of ischemia. Evaluation of the preconditioning treatment was done at the single-cell level. The binding of NO to myoglobin, giving a 6-coordinate ferrous-heme complex, was inferred from the measured Raman bands of a cardiomyocyte by comparison to pure solution of the protein in the presence of NO. A key change in the Raman spectrum was observed after perfusion of the NO-donor was completed, where, if the preconditioning treatment was successful, the bands corresponding to the nitrosyl complex were replaced by bands corresponding to metmyoglobin, Mb(III). An observation of Mb(III) bands in the Raman spectrum was made for all of the cardiomyocytes that recovered contractile function, whereas the absence of Mb(III) bands always indicated that the cardiomyocyte would be unable to recover contractile function following the simulated conditions of ischemia and reperfusion in these experiments.

  8. Functional and morphological maturation of implanted neonatal cardiomyocytes as a comparator for cell therapy.

    Science.gov (United States)

    Sato, Motoki; Carr, Carolyn A; Stuckey, Daniel J; Ishii, Hikaru; Kanda, Gaelle Kikonda; Terracciano, Cesare M N; Siedlecka, Urszula; Tatton, Louise; Watt, Suzanne M; Martin-Rendon, Enca; Clarke, Kieran; Harding, Sian E

    2010-07-01

    Knowledge of the rate of development of immature cardiomyocytes after implantation into a host heart is important for studies using cell therapy. To assess this functionally, we have implanted rat neonatal cardiomyocytes (NCMs) in normal and infarcted rat heart and re-isolated them for functional assessment. Maturation of implanted bone marrow stromal cells (BMSCs) was compared under similar conditions. NCMs from green fluorescent protein (GFP) transgenic rats were implanted into adult normal or infarcted rat hearts and re-isolated after 1, 2, or 4 weeks by standard enzymatic digestion. BMSCs labeled with DiI and iron oxide were implanted into rats with myocardial infarction and cells re-isolated 1, 2, 5, 6, and 16 weeks later. GFP-labeled myocytes approaching the adult morphology were detected 2 weeks after implantation of NCMs, but were significantly shorter than adult host myocytes and had reduced contractility. By 4 weeks after implantation, re-isolated GFP-labeled myocytes were close to the adult phenotype in contractile characteristics, although still significantly shorter. Infarction of the host did not alter the rate of maturation of implanted cells. After implantation of BMSCs, small numbers of functional DiI-labeled myocytes were re-isolated from 4/11 animals but were more mature than expected from the NCM studies. This adds evidence that BMSC-derived cardiomyocytes were not a result of transdifferentiation. The maturation rate of implanted NCMs represents a benchmark against which to evaluate the likely rate of formation of fully functional cardiomyocytes from implanted cells. PMID:20053126

  9. A piezoelectric electrospun platform for in situ cardiomyocyte contraction analysis

    Science.gov (United States)

    Beringer, Laura Toth

    hyperpolarized state, proving their potential use as contractile analysis microdevices. The third and final aim of this dissertation was to be able to measure contraction events from both cultured cardiomyocytes and whole tissues in situ. Rat neonatal cardiomyocytes grew on the prepared collagen/PVDF-TrFe nanogenerators and yielded a distinct signal after 8 days of growth. These contractions were verified with live cell imaging and video recording. In addition, cardiomyocyte exposure to the drug isoproterenol increased contraction strength and frequency, which was reflected in the nanogenerator recordings. Frog whole heart and heart tissue slices also were interfaced with the fabricated nanogenerators and signals were recorded. The same held true for heart slices from male Sprague-Dawley rats. These signals were determined to be statistically different compared to the control baseline nanogenerator recordings in media in the absence of cell culture. Overall the fabricated nanogenerators have demonstrated their potential to be used as in situ analysis tools for contractile events and have potential in the field of personalized medicine and drug diagnostic assays. The facile fabrication and ease of setup to obtain the electrical voltage signal corresponding to the contractile events are what sets the nanogenerator apart from any polymer based sensor available today.

  10. Modulatory effects of taurine on jejunal contractility

    OpenAIRE

    Yao, Q Y; Chen, D. P.; D.M. Ye; Y.P. Diao; Lin, Y.

    2014-01-01

    Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Tau...

  11. Mitochondrial Dysfunction in Diabetic Cardiomyopathy

    OpenAIRE

    Jennifer G. Duncan

    2011-01-01

    Cardiovascular disease is common in patients with diabetes and is a significant contributor to the high mortality rates associated with diabetes. Heart failure is common in diabetic patients, even in the absence of coronary artery disease or hypertension, an entity known as diabetic cardiomyopathy. Evidence indicates that myocardial metabolism is altered in diabetes, which likely contributes to contractile dysfunction and ventricular failure. The mitochondria are the center of metabolism, and...

  12. Lessons from the heart: mirroring electrophysiological characteristics during cardiac development to in vitro differentiation of stem cell derived cardiomyocytes.

    Science.gov (United States)

    van den Heuvel, Nikki H L; van Veen, Toon A B; Lim, Bing; Jonsson, Malin K B

    2014-02-01

    The ability of human pluripotent stem cells (hPSCs) to differentiate into any cell type of the three germ layers makes them a very promising cell source for multiple purposes, including regenerative medicine, drug discovery, and as a model to study disease mechanisms and progression. One of the first specialized cell types to be generated from hPSC was cardiomyocytes (CM), and differentiation protocols have evolved over the years and now allow for robust and large-scale production of hPSC-CM. Still, scientists are struggling to achieve the same, mainly ventricular, phenotype of the hPSC-CM in vitro as their adult counterpart in vivo. In vitro generated cardiomyocytes are generally described as fetal-like rather than adult. In this review, we compare the in vivo development of cardiomyocytes to the in vitro differentiation of hPSC into CM with focus on electrophysiology, structure and contractility. Furthermore, known epigenetic changes underlying the differences between adult human CM and CM differentiated from pluripotent stem cells are described. This should provide the reader with an extensive overview of the current status of human stem cell-derived cardiomyocyte phenotype and function. Additionally, the reader will gain insight into the underlying signaling pathways and mechanisms responsible for cardiomyocyte development.

  13. Mechanisms underlying the impaired contractility of diabetic cardiomyopathy

    Institute of Scientific and Technical Information of China (English)

    Marie-Louise; Ward; David; J; Crossman

    2014-01-01

    Cardiac dysfunction is a well-known consequence of diabetes,with sustained hyperglycaemia leading to the development of a cardiomyopathy that is independent of cardiovascular disease or hypertension.Animal models of diabetes are commonly used to study the pathophysiology of diabetic cardiomyopathy,with the hope that increased knowledge will lead ultimately to better therapeutic strategies being developed.At physiological temperature,left ventricular trabeculae isolated from the streptozotocin rat model of type 1 diabetes showed decreased stress and prolonged relaxation,but with no evidence that decreased contractility was a result of altered myocardial Ca2+handling.Although sarcoplasmic reticulum(SR)Ca2+reuptake appeared slower in diabetic trabeculae,it was offset by an increase in actionpotential duration,thereby maintaining SR Ca2+content and favouring increased contraction force.Frequency analysis of t-tubule distribution by confocal imaging of ventricular tissue labeled with wheat germ agglutinin or ryanodine receptor antibodies showed a reduced T-power for diabetic tissue,but the differences were minor in comparison to other models of heart failure.The contractile dysfunction appeared to be the result of disrupted F-actin in conjunction with the increased typeⅠcollagen,with decreased myofilament Ca2+sensitivity contributing to the slowed relaxation.

  14. Modulatory effects of taurine on jejunal contractility

    Directory of Open Access Journals (Sweden)

    Q.Y. Yao

    2014-12-01

    Full Text Available Taurine (2-aminoethanesulfonic acid is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

  15. Modulatory effects of taurine on jejunal contractility

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Q.Y.; Chen, D.P.; Ye, D.M.; Diao, Y.P.; Lin, Y. [Dalian Medical University, Dalian, Liaoning (China)

    2014-10-14

    Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca{sup 2+} dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

  16. Studies of diaphragm fatigue and dysfunction

    OpenAIRE

    Radell, Peter J

    2001-01-01

    Diaphragm fatigue and dysfunction are important components of acute and chronic respiratory pump failure. We lack knowledge about the nature of diaphragm fatigue and the pathophysiological and morphological changes that occur in the diaphragm after prolonged mechanical ventilation. This thesis studied two aspects of diaphragm function. Diaphragm contractility and oxidative metabolism were studied during inspiratory resistive loaded breathing (IRB) and hypoxia, and diaphragm ...

  17. Insulin improves cardiac myocytes contractile function recovery in simulated ischemia-reperfusion: Key role of Akt

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; ZHANG Haifeng; FAN Qian; MA Xinliang; GAO Feng

    2003-01-01

    The present study examined cardiac myocyte contractile and Ca2+ transient responses to insulin during simulated ischemia/reperfusion (I/R) and furtherinvestigated the role of protein kinase B (Akt) in the insulin- induced inotropic effect. Ventricular myocytes were enzymatically isolated from adult Sprague-Dawley rats and perfused with Tyrode solution while electrically field-stimulated. Simulated I/R was induced by perfusing the cells with chemical anoxic solution including sodium cyanide-sodium lactate for 15 min followed by reperfusion with normal oxygenated Tyrode solution with or without insulin. It is found that insulin only at concentration as high as 10 IU/L could increase cell shortening (16±5%, P < 0.05) in normal myocytes, whereas it concentration-dependently (0.01-10 IU/L) increased the contraction,the velocity of shortening/releng- theningand Ca2+ transient in I/R myocytes. In addition, insulin treatment (1 IU/L) increased Akt phosphorylation of I/R cardiomyocytes by 2.4-fold compared with that of the control (P < 0.01). Most importantly, pretreatment with LY 294002, a specific inhibitor of phosphatidylinositol 3′-kinase (PI3-kinase), significantly inhibited both Akt phosphorylation and the positive inotropic response to insulin in the I/R cardiomyocytes. These results suggest that insulin exerts direct positive inotropic effect by increasing Ca2+ transient of cardiomyocytes, which is enhanced in the pathological condition of I/R. Akt activation plays an important role in the insulin-induced improvement of myocyte contractile function following I/R.

  18. Simvastatin inhibits leptin-induced hypertrophy in cultured neonatal rat cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    Tai-ping HU; Fang-ping XU; Yuan-jian LI; Jian-dong LUO

    2006-01-01

    Aim:To test the hypothesis that statins inhibit leptin-induced hypertrophy in cultured neonatal rat cardiomyocytes.Methods:Cultured neonatal rat cardiomyocytes were used to evaluate the effects of simvastatin on leptininduced hypertrophy.Intracellular reactive oxygen species (ROS) levels were determined by using 2',7'-dichlorofluorescein diacetate (DCF-DA) fluorescence.Total intracellular RNA and cell protein content,which serve as cell proliferative markers,were assayed by using propidium iodide (PI) fluorescence and the Bio-Rad DC protein assay.respectively.The cell surface area,an indicator of cell hypertrophy,was quantified by using Leica image analysis software.Results:After 72 h treatment,1eptin markedly increased RNA 1evels,cell surface area,and total cell protein levels in cardiomyocytes,which were significantly inhibited by simvastatin or catalase treatment.ROS levels were significantly elevated in cardiomyocytes treated with leptin for 4 h compared with those cells without leptin treatment.The increase in ROS levels in cardiomyocytes induced by leptin was reversed by treatment with simvastatin and catalase.Conclusion:Simvastatin inhibits leptin-induced ROS-mediated hyperophy in cultured neonatal rat cardiac myocytes.Statin therapy may provide an effective means of improving cardiac dysfunction in obese humans.

  19. CUEDC2 modulates cardiomyocyte oxidative capacity by regulating GPX1 stability.

    Science.gov (United States)

    Jian, Zhao; Liang, Bing; Pan, Xin; Xu, Guang; Guo, Sai-Sai; Li, Ting; Zhou, Tao; Xiao, Ying-Bin; Li, Ai-Ling

    2016-01-01

    The irreversible loss of cardiomyocytes due to oxidative stress is the main cause of heart dysfunction following ischemia/reperfusion (I/R) injury and ageing-induced cardiomyopathy. Here, we report that CUEDC2, a CUE domain-containing protein, plays a critical role in oxidative stress-induced cardiac injury. Cuedc2(-/-) cardiomyocytes exhibited a greater resistance to oxidative stress-induced cell death. Loss of CUEDC2 enhanced the antioxidant capacity of cardiomyocytes, promoted reactive oxygen species (ROS) scavenging, and subsequently inhibited the redox-dependent activation of signaling pathways. Notably, CUEDC2 promoted E3 ubiquitin ligases tripartite motif-containing 33 (TRIM33)-mediated the antioxidant enzyme, glutathione peroxidase 1 (GPX1) ubiquitination, and proteasome-dependent degradation. Ablation of CUEDC2 upregulated the protein level of GPX1 in the heart significantly. Strikingly, in vivo, the infarct size of Cuedc2(-/-) heart was significantly decreased after I/R injury, and aged Cuedc2(-/-) mice preserved better heart function as the overall ROS levels in their hearts were significantly lower. Our results demonstrated a novel role of CUEDC2 in cardiomyocyte death regulation. Manipulating CUEDC2 level might be an attractive therapeutic strategy for promoting cardiomyocyte survival following oxidative stress-induced cardiac injury. PMID:27286733

  20. Compensatory Hypertrophy of Skeletal Muscle: Contractile Characteristics

    Science.gov (United States)

    Ianuzzo, C. D.; Chen, V.

    1977-01-01

    Describes an experiment using rats that demonstrates contractile characteristics of normal and hypertrophied muscle. Compensatory hypertrophy of the plantaris muscle is induced by surgical removal of the synergistic gastrocnemium muscle. Includes methods for determination of contractile properties of normal and hypertrophied muscle and…

  1. Resveratrol treatment reduces cardiac progenitor cell dysfunction and prevents morpho-functional ventricular remodeling in type-1 diabetic rats.

    Directory of Open Access Journals (Sweden)

    Francesca Delucchi

    Full Text Available Emerging evidence suggests that both adult cardiac cell and the cardiac stem/progenitor cell (CSPC compartments are involved in the patho-physiology of diabetic cardiomyopathy (DCM. We evaluated whether early administration of Resveratrol, a natural antioxidant polyphenolic compound, in addition to improving cardiomyocyte function, exerts a protective role on (i the progenitor cell pool, and (ii the myocardial environment and its impact on CSPCs, positively interfering with the onset of DCM phenotype. Adult Wistar rats (n = 128 with streptozotocin-induced type-1 diabetes were either untreated (D group; n = 54 or subjected to administration of trans-Resveratrol (i.p. injection: 2.5 mg/Kg/day; DR group; n = 64. Twenty-five rats constituted the control group (C. After 1, 3 or 8 weeks of hyperglycemia, we evaluated cardiac hemodynamic performance, and cardiomyocyte contractile properties and intracellular calcium dynamics. Myocardial remodeling and tissue inflammation were also assessed by morphometry, immunohistochemistry and immunoblotting. Eventually, the impact of the diabetic "milieu" on CSPC turnover was analyzed in co-cultures of healthy CSPCs and cardiomyocytes isolated from D and DR diabetic hearts. In untreated animals, cardiac function was maintained during the first 3 weeks of hyperglycemia, although a definite ventricular remodeling was already present, mainly characterized by a marked loss of CSPCs and adult cardiac cells. Relevant signs of ventricular dysfunction appeared after 8 weeks of diabetes, and included: 1 a significant reduction in ±dP/dt in comparison with C group, 2 a prolongation of isovolumic contraction/relaxation times, 3 an impaired contraction of isolated cardiomyocytes associated with altered intracellular calcium dynamics. Resveratrol administration reduced atrial CSPC loss, succeeded in preserving the functional abilities of CSPCs and mature cardiac cells, improved cardiac environment by reducing

  2. Protection of Cardiomyocytes from Ischemic/Hypoxic Cell Death via Drbp1 and pMe2GlyDH in Cardio-specific ARC Transgenic Mice*

    Science.gov (United States)

    Pyo, Jong-Ok; Nah, Jihoon; Kim, Hyo-Jin; Chang, Jae-Woong; Song, Young-Wha; Yang, Dong-Kwon; Jo, Dong-Gyu; Kim, Hyung-Ryong; Chae, Han-Jung; Chae, Soo-Wan; Hwang, Seung-Yong; Kim, Seung-Jun; Kim, Hyo-Joon; Cho, Chunghee; Oh, Chang-Gyu; Park, Woo Jin; Jung, Yong-Keun

    2008-01-01

    The ischemic death of cardiomyocytes is associated in heart disease and heart failure. However, the molecular mechanism underlying ischemic cell death is not well defined. To examine the function of apoptosis repressor with a caspase recruitment domain (ARC) in the ischemic/hypoxic damage of cardiomyocytes, we generated cardio-specific ARC transgenic mice using a mouse α-myosin heavy chain promoter. Compared with the control, the hearts of ARC transgenic mice showed a 3-fold overexpression of ARC. Langendoff preparation showed that the hearts isolated from ARC transgenic mice exhibited improved recovery of contractile performance during reperfusion. The cardiomyocytes cultured from neonatal ARC transgenic mice were significantly resistant to hypoxic cell death. Furthermore, the ARC C-terminal calcium-binding domain was as potent to protect cardiomyocytes from hypoxic cell death as ARC. Genome-wide RNA expression profiling uncovered a list of genes whose expression was changed (>2-fold) in ARC transgenic mice. Among them, expressional regulation of developmentally regulated RNA-binding protein 1 (Drbp1) or the dimethylglycine dehydrogenase precursor (pMe2GlyDH) affected hypoxic death of cardiomyocytes. These results suggest that ARC may protect cardiomyocytes from hypoxic cell death by regulating its downstream, Drbp1 and pMe2GlyDH, shedding new insights into the protection of heart from hypoxic damages. PMID:18782777

  3. Extracellular mtDNA activates NF-κB via toll-like receptor 9 and induces cell death in cardiomyocytes.

    Science.gov (United States)

    Bliksøen, Marte; Mariero, Lars Henrik; Torp, May Kristin; Baysa, Anton; Ytrehus, Kirsti; Haugen, Fred; Seljeflot, Ingebjørg; Vaage, Jarle; Valen, Guro; Stensløkken, Kåre-Olav

    2016-07-01

    Acute myocardial infarction (AMI) causes sterile inflammation, which exacerbates tissue injury. Elevated levels of circulating mitochondrial DNA (mtDNA) have been associated with AMI. We hypothesized that mtDNA triggers an innate immune response via TLR9 and NF-κB activation, causing cardiomyocyte injury. Murine cardiomyocytes express TLR9 mRNA and protein and were able to internalize fluorescently labeled mouse mtDNA. Incubation of human embryonic kidney cells with serum from AMI patients containing naturally elevated levels of mtDNA induced TLR9-dependent NF-κB activity. This effect was mimicked by isolated mtDNA. mtDNA activated NF-κB in reporter mice both in vivo and in isolated cardiomyocytes. Moreover, incubation of isolated cardiomyocytes with mtDNA induced cell death after 4 and 24 h. Laser confocal microscopy showed that incubation of cardiomyocytes with mtDNA accelerated mitochondrial depolarization induced by reactive oxygen species. In contrast to mtDNA, isolated total DNA did not activate NF-κB nor induce cell death. In conclusion, mtDNA can induce TLR9-dependent NF-κB activation in reporter cells and activate NF-κB in cardiomyocytes. In cardiomyocytes, mtDNA causes mitochondrial dysfunction and death. Endogenous mtDNA in the extracellular space is a danger signal with direct detrimental effects on cardiomyocytes. PMID:27164906

  4. Evidence for Cardiomyocyte Renewal in Humans

    Energy Technology Data Exchange (ETDEWEB)

    Bergmann, O; Bhardwaj, R D; Bernard, S; Zdunek, S; Barnabe-Heider, F; Walsh, S; Zupicich, J; Alkass, K; Buchholz, B A; Druid, H; Jovinge, S; Frisen, J

    2008-10-14

    It has been difficult to establish whether we are limited to the heart muscle cells we are born with or if cardiomyocytes are generated also later in life. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, into DNA to establish the age of cardiomyocytes in humans. We report that cardiomyocytes renew, with a gradual decrease from 1% turning over annually at the age of 20 to 0.3% at the age of 75. Less than 50% of cardiomyocytes are exchanged during a normal lifespan. The capacity to generate cardiomyocytes in the adult human heart suggests that it may be rational to work towards the development of therapeutic strategies aiming to stimulate this process in cardiac pathologies.

  5. Cellular contractility requires ubiquitin mediated proteolysis.

    Directory of Open Access Journals (Sweden)

    Yuval Cinnamon

    Full Text Available BACKGROUND: Cellular contractility, essential for cell movement and proliferation, is regulated by microtubules, RhoA and actomyosin. The RhoA dependent kinase ROCK ensures the phosphorylation of the regulatory Myosin II Light Chain (MLC Ser19, thereby activating actomyosin contractions. Microtubules are upstream inhibitors of contractility and their depolymerization or depletion cause cells to contract by activating RhoA. How microtubule dynamics regulates RhoA remains, a major missing link in understanding contractility. PRINCIPAL FINDINGS: We observed that contractility is inhibited by microtubules not only, as previously reported, in adherent cells, but also in non-adhering interphase and mitotic cells. Strikingly we observed that contractility requires ubiquitin mediated proteolysis by a Cullin-RING ubiquitin ligase. Inhibition of proteolysis, ubiquitination and neddylation all led to complete cessation of contractility and considerably reduced MLC Ser19 phosphorylation. CONCLUSIONS: Our results imply that cells express a contractility inhibitor that is degraded by ubiquitin mediated proteolysis, either constitutively or in response to microtubule depolymerization. This degradation seems to depend on a Cullin-RING ubiquitin ligase and is required for cellular contractions.

  6. Cardiac dysfunction in cirrhosis - does adrenal function play a role? A hypothesis

    DEFF Research Database (Denmark)

    Theocharidou, Eleni; Krag, Aleksander; Bendtsen, Flemming;

    2013-01-01

    Cirrhotic cardiomyopathy (CCM), a condition of unknown pathogenesis, is characterized by suboptimal ventricular contractile response to stress, diastolic dysfunction and QT interval prolongation. It is most often found in patients with advanced cirrhosis. It is clinically relevant during stressfu...

  7. Cardiomyocyte behavior on biodegradable polyurethane/gold nanocomposite scaffolds under electrical stimulation.

    Science.gov (United States)

    Ganji, Yasaman; Li, Qian; Quabius, Elgar Susanne; Böttner, Martina; Selhuber-Unkel, Christine; Kasra, Mehran

    2016-02-01

    Following a myocardial infarction (MI), cardiomyocytes are replaced by scar tissue, which decreases ventricular contractile function. Tissue engineering is a promising approach to regenerate such damaged cardiomyocyte tissue. Engineered cardiac patches can be fabricated by seeding a high density of cardiac cells onto a synthetic or natural porous polymer. In this study, nanocomposite scaffolds made of gold nanotubes/nanowires incorporated into biodegradable castor oil-based polyurethane were employed to make micro-porous scaffolds. H9C2 cardiomyocyte cells were cultured on the scaffolds for one day, and electrical stimulation was applied to improve cell communication and interaction in neighboring pores. Cells on scaffolds were examined by fluorescence microscopy and scanning electron microscopy, revealing that the combination of scaffold design and electrical stimulation significantly increased cell confluency of H9C2 cells on the scaffolds. Furthermore, we showed that the gene expression levels of Nkx2.5, atrial natriuretic peptide (ANF) and natriuretic peptide precursor B (NPPB), which are functional genes of the myocardium, were up-regulated by the incorporation of gold nanotubes/nanowires into the polyurethane scaffolds, in particular after electrical stimulation. PMID:26652343

  8. Caveolin-3 promotes a vascular smooth muscle contractile phenotype

    Directory of Open Access Journals (Sweden)

    Jorge L. Gutierrez-Pajares

    2015-06-01

    Full Text Available Epidemiological studies have demonstrated the importance of cardiovascular diseases in Western countries. Among the cell types associated with a dysfunctional vasculature, smooth muscle cells are believed to play an essential role in the development of these illnesses. Vascular smooth muscle cells are key regulators of the vascular tone and also have an important function in the development of atherosclerosis and restenosis. While in the normal vasculature contractile smooth muscle cells are predominant, in atherosclerotic vascular lesions, synthetic cells migrate toward the neointima, proliferate, and synthetize extracellular matrix proteins. In the present study, we have examined the role of caveolin-3 in the regulation of smooth muscle cell phenotype. Caveolin-3 is expressed in vivo in normal arterial smooth muscle cells, but its expression appears to be lost in cultured smooth muscle cells. Our data show that caveolin-3 expression in the A7r5 smooth muscle cell line is associated with increased expression of contractility markers such as smooth muscle  actin, smooth muscle myosin heavy chain but decreased expression of the synthetic phenotype markers such as p-Elk and Klf4. Moreover, we also show that caveolin-3 expression can reduce proliferation upon treatment with LDL or PDGF. Finally, we show that caveolin-3-expressing smooth muscle cells are less sensitive to apoptosis than control cells upon treatment with oxidized LDL. Taken together, our data suggest that caveolin-3 can regulate the phenotypic switch between contractile and synthetic smooth muscle cells. A better understanding of the factors regulating caveolin-3 expression and function in this cell type will permit the development of a better comprehension of the factors regulating smooth muscle function in atherosclerosis and restenosis.

  9. Analysis of mitochondrial 3D-deformation in cardiomyocytes during active contraction reveals passive structural anisotropy of orthogonal short axes.

    Directory of Open Access Journals (Sweden)

    Yael Yaniv

    Full Text Available The cardiomyocyte cytoskeleton, composed of rigid and elastic elements, maintains the isolated cell in an elongated cylindrical shape with an elliptical cross-section, even during contraction-relaxation cycles. Cardiomyocyte mitochondria are micron-sized, fluid-filled passive spheres distributed throughout the cell in a crystal-like lattice, arranged in pairs sandwiched between the sarcomere contractile machinery, both longitudinally and radially. Their shape represents the extant 3-dimensional (3D force-balance. We developed a novel method to examine mitochondrial 3D-deformation in response to contraction and relaxation to understand how dynamic forces are balanced inside cardiomyocytes. The variation in transmitted light intensity induced by the periodic lattice of myofilaments alternating with mitochondrial rows can be analyzed by Fourier transformation along a given cardiomyocyte axis to measure mitochondrial deformation along that axis. This technique enables precise detection of changes in dimension of ∼1% in ∼1 µm (long-axis structures with 8 ms time-resolution. During active contraction (1 Hz stimulation, mitochondria deform along the length- and width-axes of the cell with similar deformation kinetics in both sarcomere and mitochondrial structures. However, significant deformation anisotropy (without hysteresis was observed between the orthogonal short-axes (i.e., width and depth of mitochondria during electrical stimulation. The same degree of deformation anisotropy was also found between the myocyte orthogonal short-axes during electrical stimulation. Therefore, the deformation of the mitochondria reflects the overall deformation of the cell, and the apparent stiffness and stress/strain characteristics of the cytoskeleton differ appreciably between the two cardiomyocyte orthogonal short-axes. This method may be applied to obtaining a better understanding of the dynamic force-balance inside cardiomyocytes and of changes in the

  10. Requirements for disordered actomyosin bundle contractility

    CERN Document Server

    Lenz, Martin

    2011-01-01

    Actomyosin contractility is essential for biological force generation, and is well understood in highly ordered structures such as striated muscle. In vitro experiments have shown that non-sarcomeric bundles comprised only of F-actin and myosin thick filaments can also display contractile behavior, which cannot be described by standard muscle models. Here we investigate the microscopic symmetries underlying this process in large non-sarcomeric bundles with long actin filaments. We prove that contractile behavior requires non-identical motors that generate large enough forces to probe the nonlinear elastic behavior of F-actin. A simple disordered bundle model demonstrates a contraction mechanism based on these assumptions and predicts realistic bundle deformations. Recent experimental observations of F-actin buckling in in vitro contractile bundles support our model.

  11. Endothelial dysfunction: EDCF revisited

    Institute of Scientific and Technical Information of China (English)

    PAUL M Vanhoutte

    2008-01-01

    Endothelial cells can initiate contraction (constriction) of the vascular smooth muscle cells that surround them. Such endothelium-dependent, acute increases in contractile tone can be due to the withdrawal of the production of nitric oxide, to the production of vasoconstrictor peptides (angiotensin Ⅱ, endothelin-1), to the formation of oxygen-derived free radicals(superoxide anions) and/or the release of vasoconstrictor metabolites of arachidonic acid. The latter have been termed endothelium-derived contracting factor (EDCF) as they can contribute to moment-to-moment changes in contractile activity of the underlying vascular smooth muscle cells. To judge from animal experiments, EDCF-mediated responses are exacerbated when the production of nitric oxide is impaired as well as by aging, spontaneous hypertension and diabetes. To judge from human studies, they contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive patients. Since EDCF causes vasoconstriction by activation of the TP-receptors on the vascular smooth muscle cells, selective antagonists at these receptors prevent endothelium-dependent contractions, and curtail the endothelial dysfunction in hypertension and diabetes.

  12. Transcriptional Landscape of Cardiomyocyte Maturation

    Directory of Open Access Journals (Sweden)

    Hideki Uosaki

    2015-11-01

    Full Text Available Decades of progress in developmental cardiology has advanced our understanding of the early aspects of heart development, including cardiomyocyte (CM differentiation. However, control of the CM maturation that is subsequently required to generate adult myocytes remains elusive. Here, we analyzed over 200 microarray datasets from early embryonic to adult hearts and identified a large number of genes whose expression shifts gradually and continuously during maturation. We generated an atlas of integrated gene expression, biological pathways, transcriptional regulators, and gene regulatory networks (GRNs, which show discrete sets of key transcriptional regulators and pathways activated or suppressed during CM maturation. We developed a GRN-based program named MatStatCM that indexes CM maturation status. MatStatCM reveals that pluripotent-stem-cell-derived CMs mature early in culture but are arrested at the late embryonic stage with aberrant regulation of key transcription factors. Our study provides a foundation for understanding CM maturation.

  13. Cardiomyocyte-specific expression of lamin a improves cardiac function in Lmna-/- mice.

    Directory of Open Access Journals (Sweden)

    Richard L Frock

    Full Text Available Lmna(-/- mice display multiple tissue defects and die by 6-8 weeks of age reportedly from dilated cardiomyopathy with associated conduction defects. We sought to determine whether restoration of lamin A in cardiomyocytes improves cardiac function and extends the survival of Lmna(-/- mice. We observed increased total desmin protein levels and disorganization of the cytoplasmic desmin network in ~20% of Lmna(-/- ventricular myocytes, rescued in a cell-autonomous manner in Lmna(-/- mice expressing a cardiac-specific lamin A transgene (Lmna(-/-; Tg. Lmna(-/-; Tg mice displayed significantly increased contractility and preservation of myocardial performance compared to Lmna(-/- mice. Lmna(-/-; Tg mice attenuated ERK1/2 phosphorylation relative to Lmna(-/- mice, potentially underlying the improved localization of connexin43 to the intercalated disc. Electrocardiographic recordings from Lmna(-/- mice revealed arrhythmic events and increased frequency of PR interval prolongation, which is partially rescued in Lmna(-/-; Tg mice. These findings support our observation that Lmna(-/-; Tg mice have a 12% median extension in lifespan compared to Lmna(-/- mice. While significant, Lmna(-/-; Tg mice only have modest improvement in cardiac function and survival likely stemming from the observation that only 40% of Lmna(-/-; Tg cardiomyocytes have detectable lamin A expression. Cardiomyocyte-specific restoration of lamin A in Lmna(-/- mice improves heart-specific pathology and extends lifespan, demonstrating that the cardiac pathology of Lmna(-/- mice limits survival. The expression of lamin A is sufficient to rescue certain cellular defects associated with loss of A-type lamins in cardiomyocytes in a cell-autonomous fashion.

  14. Identification, Selection, and Enrichment of Cardiomyocyte Precursors

    Directory of Open Access Journals (Sweden)

    Bianca Ferrarini Zanetti

    2013-01-01

    Full Text Available The large-scale production of cardiomyocytes is a key step in the development of cell therapy and tissue engineering to treat cardiovascular diseases, particularly those caused by ischemia. The main objective of this study was to establish a procedure for the efficient production of cardiomyocytes by reprogramming mesenchymal stem cells from adipose tissue. First, lentiviral vectors expressing neoR and GFP under the control of promoters expressed specifically during cardiomyogenesis were constructed to monitor cell reprogramming into precardiomyocytes and to select cells for amplification and characterization. Cellular reprogramming was performed using 5′-azacytidine followed by electroporation with plasmid pOKS2a, which expressed Oct4, Sox2, and Klf4. Under these conditions, GFP expression began only after transfection with pOKS2a, and less than 0.015% of cells were GFP+. These GFP+ cells were selected for G418 resistance to find molecular markers of cardiomyocytes by RT-PCR and immunocytochemistry. Both genetic and protein markers of cardiomyocytes were present in the selected cells, with some variations among them. Cell doubling time did not change after selection. Together, these results indicate that enrichment with vectors expressing GFP and neoR under cardiomyocyte-specific promoters can produce large numbers of cardiomyocyte precursors (CMPs, which can then be differentiated terminally for cell therapy and tissue engineering.

  15. Cardiomyocyte marker expression in a human lymphocyte cell line using mouse cardiomyocyte extract.

    Science.gov (United States)

    Vojdani, Zahra; Tavakolinejad, Sima; Talaei-Khozani, Tahereh; Esmaeilpour, Tahereh; Rasooli, Manuchehr

    2011-03-01

    Cell transplantation shows potential for the treatment of cardiac diseases. Embryonic stem cells, cord blood and mesenchymal stem cells have been suggested as sources for transplantation therapy. Because of some technical limitations with the use of stem cells, transdifferentiation of fully differentiated cells is a potentially useful alternative. We investigated whether human peripheral blood cells could transdifferentiate into cardiomyocyte. Transdifferentiation was induced in a human B lymphocyte cell line (Raji). Cardiomyocyte extract was prepared from adult mouse cardiomyocytes. The cells were treated with 5-aza-2-deoxycytidine and trichostatin A, permeabilized with streptolysin O, and exposed to the mouse cardiomyocyte extract. They were cultured for 10 days, 3 weeks and 4 weeks. Cardiomyocyte markers were detected with immunohistochemistry and flow cytometry. Immunocytochemistry revealed that some cells expressed myosin heavy chain, α-actinin and cardiac troponin T after 3 and 4 weeks. Flow cytometry confirmed these data. In cells exposed to trichostatin A and 5-aza-2-deoxycytidine and permeabilized in the presence of the cardiomyocyte extract, troponin T expression was seen in 3.53% of the cells and 3.11% of them expressed α-actinin. After exposure to the cardiomyocyte extract, some permeabilized cells adhered to the plate loosely; however, the morphology did not change significantly, and they continued to show a rounded shape after 4 weeks. Our treated lymphocytes expressed cardiomyocyte markers. Our results suggest that lymphocytes may be useful in future research as a source of cells for reprogramming procedures. PMID:21547694

  16. Zinc-induced cardiomyocyte relaxation in a rat model of hyperglycemia is independent of myosin isoform

    Directory of Open Access Journals (Sweden)

    Yi Ting

    2012-11-01

    Full Text Available Abstract It has been reported previously that diabetic cardiomyopathy can be inhibited or reverted with chronic zinc supplementation. In the current study, we hypothesized that total cardiac calcium and zinc content is altered in early onset diabetes mellitus characterized in part as hyperglycemia (HG and that exposure of zinc ion (Zn2+ to isolated cardiomyocytes would enhance contraction-relaxation function in HG more so than in nonHG controls. To better control for differential cardiac myosin isoform expression as occurs in rodents after β-islet cell necrosis, hypothyroidism was induced in 16 rats resulting in 100% β-myosin heavy chain expression in the heart. β-Islet cell necrosis was induced in half of the rats by streptozocin administration. After 6 wks of HG, both HG and nonHG controls rats demonstrated similar myofilament performance measured as thin filament calcium sensitivity, native thin filament velocity in the myosin motility assay and contractile velocity and power. Extracellular Zn2+ reduced cardiomyocyte contractile function in both groups, but enhanced relaxation function significantly in the HG group compared to controls. Most notably, a reduction in diastolic sarcomere length with increasing pacing frequencies, i.e., incomplete relaxation, was more pronounced in the HG compared to controls, but was normalized with extracellular Zn2+ application. This is a novel finding implicating that the detrimental effect of HG on cardiomyocyte Ca2+ regulation can be amelioration by Zn2+. Among the many post-translational modifications examined, only phosphorylation of ryanodine receptor (RyR at S-2808 was significantly higher in HG compared to nonHG. We did not find in our hypothyroid rats any differentiating effects of HG on myofibrillar protein phosphorylation, lysine acetylation, O-linked N-acetylglucosamine and advanced glycated end-products, which are often implicated as complicating factors in cardiac performance due to HG. Our

  17. Studies of membrane fluidity and heart contractile force in Trypanosoma cruzi infected mice

    Directory of Open Access Journals (Sweden)

    Julio E Enders

    2004-11-01

    Full Text Available In Chagas disease serious cardiac dysfunction can appear. We specifically studied the cardiac function by evaluating: ventricle contractile force and norepinephrine response, affinity and density of beta-adrenergic receptors, dynamic properties of myocardial membranes, and electrocardiography. Albino swiss mice (n = 250 were infected with 55 trypomastigotes, Tulahuen strain and studied at 35, 75, and 180 days post-infection, that correspond to the acute, indeterminate, and chronic phase respectively. Cardiac beta-adrenergic receptors' affinity, myocardial contractility, and norepinephrine response progressively decreased from the acute to the chronic phase of the disease (p < 0.01. The density (expressed as fmol/mg.prot of the receptors was similar to non-infected mice (71.96 ± 0.36 in both the acute (78.24 ± 1.67 and indeterminate phases (77.28 ± 0.91, but lower in the chronic disease (53.32 ± 0.71. Electrocardiographic abnormalities began in the acute phase and were found in 65% of the infected-mice during the indeterminate and chronic phases. Membrane contents of triglycerides, cholesterol, and anisotropy were similar in all groups. A quadratic correlation between the affinity to beta-adrenergic receptors and cardiac contractile force was obtained. In conclusion the changes in cardiac beta-adrenergic receptors suggests a correlation between the modified beta-adrenergic receptors affinity and the cardiac contractile force.

  18. Mitochondria-targeted antioxidant preserves contractile properties and mitochondrial function of skeletal muscle in aged rats.

    Science.gov (United States)

    Javadov, Sabzali; Jang, Sehwan; Rodriguez-Reyes, Natividad; Rodriguez-Zayas, Ana E; Soto Hernandez, Jessica; Krainz, Tanja; Wipf, Peter; Frontera, Walter

    2015-11-24

    Mitochondrial dysfunction plays a central role in the pathogenesis of sarcopenia associated with a loss of mass and activity of skeletal muscle. In addition to energy deprivation, increased mitochondrial ROS damage proteins and lipids in aged skeletal muscle. Therefore, prevention of mitochondrial ROS is important for potential therapeutic strategies to delay sarcopenia. This study elucidates the pharmacological efficiency of the new developed mitochondria-targeted ROS and electron scavenger, XJB-5-131 (XJB) to restore muscle contractility and mitochondrial function in aged skeletal muscle. Male adult (5-month old) and aged (29-month old) Fischer Brown Norway (F344/BN) rats were treated with XJB for four weeks and contractile properties of single skeletal muscle fibres and activity of mitochondrial ETC complexes were determined at the end of the treatment period. XJB-treated old rats showed higher muscle contractility associated with prevention of protein oxidation in both muscle homogenate and mitochondria compared with untreated counterparts. XJB-treated animals demonstrated a high activity of the respiratory complexes I, III, and IV with no changes in citrate synthase activity. These data demonstrate that mitochondrial ROS play a causal role in muscle weakness, and that a ROS scavenger specifically targeted to mitochondria can reverse age-related alterations of mitochondrial function and improve contractile properties in skeletal muscle.

  19. The Mitochondrial Calcium Uniporter Selectively Matches Metabolic Output to Acute Contractile Stress in the Heart.

    Science.gov (United States)

    Kwong, Jennifer Q; Lu, Xiyuan; Correll, Robert N; Schwanekamp, Jennifer A; Vagnozzi, Ronald J; Sargent, Michelle A; York, Allen J; Zhang, Jianyi; Bers, Donald M; Molkentin, Jeffery D

    2015-07-01

    In the heart, augmented Ca(2+) fluxing drives contractility and ATP generation through mitochondrial Ca(2+) loading. Pathologic mitochondrial Ca(2+) overload with ischemic injury triggers mitochondrial permeability transition pore (MPTP) opening and cardiomyocyte death. Mitochondrial Ca(2+) uptake is primarily mediated by the mitochondrial Ca(2+) uniporter (MCU). Here, we generated mice with adult and cardiomyocyte-specific deletion of Mcu, which produced mitochondria refractory to acute Ca(2+) uptake, with impaired ATP production, and inhibited MPTP opening upon acute Ca(2+) challenge. Mice lacking Mcu in the adult heart were also protected from acute ischemia-reperfusion injury. However, resting/basal mitochondrial Ca(2+) levels were normal in hearts of Mcu-deleted mice, and mitochondria lacking MCU eventually loaded with Ca(2+) after stress stimulation. Indeed, Mcu-deleted mice were unable to immediately sprint on a treadmill unless warmed up for 30 min. Hence, MCU is a dedicated regulator of short-term mitochondrial Ca(2+) loading underlying a "fight-or-flight" response that acutely matches cardiac workload with ATP production.

  20. The Mitochondrial Calcium Uniporter Selectively Matches Metabolic Output to Acute Contractile Stress in the Heart

    Directory of Open Access Journals (Sweden)

    Jennifer Q. Kwong

    2015-07-01

    Full Text Available In the heart, augmented Ca2+ fluxing drives contractility and ATP generation through mitochondrial Ca2+ loading. Pathologic mitochondrial Ca2+ overload with ischemic injury triggers mitochondrial permeability transition pore (MPTP opening and cardiomyocyte death. Mitochondrial Ca2+ uptake is primarily mediated by the mitochondrial Ca2+ uniporter (MCU. Here, we generated mice with adult and cardiomyocyte-specific deletion of Mcu, which produced mitochondria refractory to acute Ca2+ uptake, with impaired ATP production, and inhibited MPTP opening upon acute Ca2+ challenge. Mice lacking Mcu in the adult heart were also protected from acute ischemia-reperfusion injury. However, resting/basal mitochondrial Ca2+ levels were normal in hearts of Mcu-deleted mice, and mitochondria lacking MCU eventually loaded with Ca2+ after stress stimulation. Indeed, Mcu-deleted mice were unable to immediately sprint on a treadmill unless warmed up for 30 min. Hence, MCU is a dedicated regulator of short-term mitochondrial Ca2+ loading underlying a “fight-or-flight” response that acutely matches cardiac workload with ATP production.

  1. Right Ventricular Dysfunction in Chronic Lung Disease

    OpenAIRE

    Kolb, Todd M.; Hassoun, Paul M.

    2012-01-01

    Right ventricular dysfunction arises in chronic lung disease when chronic hypoxemia and disruption of pulmonary vascular beds contribute to increase ventricular afterload, and is generally defined by hypertrophy with preserved myocardial contractility and cardiac output. Although the exact prevalence is unknown, right ventricular hypertrophy appears to be a common complication of chronic lung disease, and more frequently complicates advanced lung disease. Right ventricular failure is rare, ex...

  2. Cardiomyocyte-specific deletion of leptin receptors causes lethal heart failure in Cre-recombinase-mediated cardiotoxicity.

    Science.gov (United States)

    Hall, Michael E; Smith, Grant; Hall, John E; Stec, David E

    2012-12-15

    Although disruption of leptin signaling is associated with obesity as well as cardiac lipid accumulation and dysfunction, it has been difficult to separate the direct effects of leptin on the heart from those associated with the effects of leptin on body weight and fat mass. Using Cre-loxP recombinase technology, we developed tamoxifen-inducible, cardiomyocyte-specific leptin receptor-deficient mice to assess the role of leptin in regulating cardiac function. Cre recombinase activation in the heart resulted in transient reduction in left ventricular systolic function which recovered to normal levels by day 10. However, when cardiomyocyte leptin receptors were deleted in the setting of Cre recombinase-induced left ventricular dysfunction, irreversible lethal heart failure was observed in less than 10 days in all mice. Heart failure after leptin receptor deletion was associated with marked decreases of cardiac mitochondrial ATP, phosphorylated mammalian target of rapamycin (mTOR), and AMP-activated kinase (pAMPK). Our results demonstrate that specific deletion of cardiomyocyte leptin receptors, in the presence of increased Cre recombinase expression, causes lethal heart failure associated with decreased cardiac energy production. These observations indicate that leptin plays an important role in regulating cardiac function in the setting of cardiac stress caused by Cre-recombinase expression, likely through actions on cardiomyocyte energy metabolism.

  3. The Adipokine Chemerin Induces Apoptosis in Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Diego Rodríguez-Penas

    2015-08-01

    Full Text Available Background: The adipokine chemerin has been associated with cardiovascular disease. We investigated the effects of chemerin on viability and intracellular signalling in murine cardiomyocytes, and the effects of insulin and TNF-α on cardiomyocyte chemerin production. Methods: Hoechst dye vital staining and cell cycle analysis were used to analyse the viability of murine cardiac cells in culture. Western blot was used to explore the phosphorylation of AKT and caspase-9 activity in neonatal rat cardiomyocytes and HL-1 cells. Finally, RT-qPCR, ELISA and western blot were performed to examine chemerin and CMKLR1 expression after insulin and TNF-α treatment in cardiac cells. Results: Chemerin treatment increased apoptosis, reduced phosphorylation of AKT at Thr308 and increased caspase-9 activity in murine cardiomyocytes. Insulin treatment lowered chemerin and CMKLR1 mRNA and protein levels, and the amount of chemerin in the cell media, while TNF-α treatment increased chemerin mRNA and protein levels but decreased expression of the CMKLR1 gene. Conclusion: Chemerin induces apoptosis, reduces AKT phosphorylation and increases the cleavage of caspase-9 in murine cardiomyocytes. The expression of chemerin is regulated by important metabolic (insulin and inflammatory (TNF-α mediators at cardiac level. Our results suggest that chemerin could play a role in the physiopathology of cardiac diseases.

  4. Stress activated contractile wavefronts in the mechanically-excitable embryonic heart

    Science.gov (United States)

    Chiou, Kevin; Majkut, Stephanie; Discher, Dennis; Lubensky, Tom; Liu, Andrea

    2014-03-01

    The heart is a prime example of a robust, active system with behavior-the heart beat-that is extraordinarily well timed and coordinated. For more than half a century, electrical activity induced by ion release and diffusion has been argued to be the mechanism driving cardiac action. But recent work indicates that this phenomenon is also regulated by mechanical activity. In the embryonic avian heart tube, the speed of the contractile wavefront traversing the heart tube with each beat is measured to be a monotonic, linear function of tissue stiffness. Traditional electrical conduction models of excitation-contraction cannot explain this dependence; such a result indicates that the myocardium is mechanically excitable. Here, we extend this work by using experimental observations of stiffness-dependent behavior in isolated cardiomyocytes as an input to study contractile wavefronts in the tissue as a whole. We model the heart tube as an active, overdamped elastic network where the primary stress mediator is the extracellular matrix. Using this simple model, we explain experimental observations of the systolic wave and predict qualitatively new behavior.

  5. Substrate stiffness-modulated registry phase correlations in cardiomyocytes map structural order to coherent beating

    Science.gov (United States)

    Dasbiswas, K.; Majkut, S.; Discher, D. E.; Safran, Samuel A.

    2015-01-01

    Recent experiments show that both striation, an indication of the structural registry in muscle fibres, as well as the contractile strains produced by beating cardiac muscle cells can be optimized by substrate stiffness. Here we show theoretically how the substrate rigidity dependence of the registry data can be mapped onto that of the strain measurements. We express the elasticity-mediated structural registry as a phase-order parameter using a statistical physics approach that takes the noise and disorder inherent in biological systems into account. By assuming that structurally registered myofibrils also tend to beat in phase, we explain the observed dependence of both striation and strain measurements of cardiomyocytes on substrate stiffness in a unified manner. The agreement of our ideas with experiment suggests that the correlated beating of heart cells may be limited by the structural order of the myofibrils, which in turn is regulated by their elastic environment.

  6. Characterization of the mechanical properties of HL-1 cardiomyocytes with high throughput magnetic tweezers

    International Nuclear Information System (INIS)

    We characterized the mechanical properties of cardiomyocyte-like HL-1 cells using our recently developed multi-pole magnetic tweezers. With the optimized design, both high force and high throughput are achieved at the same time. Force up to 100 pN can be applied on a 1 μm diameter superparamagnetic bead in a workspace with 60 μm radius, which is encircled symmetrically by 3 sharp magnetic tips. By adjusting the coil currents, both the strength and direction of force can be controlled. The result shows that both viscosity and shear elastic modulus of HL-1 cells exhibit an approximately log-normal distribution. The cells became stiffer as they matured, consistent with a transition from proliferating cells to contractile muscle tissue. Moreover, the mechanical properties of HL-1 cells show high heterogeneity, which agrees well with their physiological structure

  7. Characterization of the mechanical properties of HL-1 cardiomyocytes with high throughput magnetic tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, La; Maybeck, Vanessa; Offenhäusser, Andreas; Krause, Hans-Joachim [Institute of Bioelectronics (ICS-8/PGI-8), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany)

    2015-08-03

    We characterized the mechanical properties of cardiomyocyte-like HL-1 cells using our recently developed multi-pole magnetic tweezers. With the optimized design, both high force and high throughput are achieved at the same time. Force up to 100 pN can be applied on a 1 μm diameter superparamagnetic bead in a workspace with 60 μm radius, which is encircled symmetrically by 3 sharp magnetic tips. By adjusting the coil currents, both the strength and direction of force can be controlled. The result shows that both viscosity and shear elastic modulus of HL-1 cells exhibit an approximately log-normal distribution. The cells became stiffer as they matured, consistent with a transition from proliferating cells to contractile muscle tissue. Moreover, the mechanical properties of HL-1 cells show high heterogeneity, which agrees well with their physiological structure.

  8. Cardiomyocyte-endothelial cell control of lipoprotein lipase.

    Science.gov (United States)

    Chiu, Amy Pei-Ling; Wan, Andrea; Rodrigues, Brian

    2016-10-01

    In people with diabetes, inadequate pharmaceutical management predisposes the patient to heart failure, which is the leading cause of diabetes related death. One instigator for this cardiac dysfunction is change in fuel utilization by the heart. Thus, following diabetes, when cardiac glucose utilization is impaired, the heart undergoes metabolic transformation wherein it switches to using fats as an exclusive source of energy. Although this switching is geared to help the heart initially, in the long term, this has detrimental effects on cardiac function. These include the generation of noxious byproducts, which damage the cardiomyocytes, and ultimately result in increased morbidity and mortality. A key perpetrator that may be responsible for organizing this metabolic disequilibrium is lipoprotein lipase (LPL), the enzyme responsible for providing fat to the hearts. Either exaggeration or reduction in its activity following diabetes could lead to heart dysfunction. Given the disturbing news that diabetes is rampant across the globe, gaining more insight into the mechanism(s) by which cardiac LPL is regulated may assist other researchers in devising new therapeutic strategies to restore metabolic equilibrium, to help prevent or delay heart disease seen during diabetes. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk. PMID:26995461

  9. Troponin Ⅰ,cardiac diastolic dysfunction and restrictive cardiomyopathy

    Institute of Scientific and Technical Information of China (English)

    Xu-pei HUANG; Jian-feng DU

    2004-01-01

    Cardiomyopathies are diseases of heart muscle that are associated with cardiac dysfunction. Molecular genetic studies performed to date have demonstrated that the damage or mutations in several sarcomeric contractile protein genes are associated with the development of the diseases. In this review, cardiac troponin Ⅰ, one of the sarcomeric thin filament protein, will be discussed regarding its role in cardiac function, its deficiency-related diastolic dysfunction, and the mutation of this protein-mediated restrictive cardiomyopathy.

  10. Protective effect of intermittent hypobaric hypoxia on cardiomyocytes injury induced by hydrogen peroxide%间歇性低压低氧对过氧化氢心肌细胞损伤的保护作用

    Institute of Scientific and Technical Information of China (English)

    郭会彩; 熊晨; 李军霞; 张荣; 赵丽娟; 王永利

    2012-01-01

    Objective: To observe the protective effect and mechnism of intermittent hypobaric hypoxia(IHH) on cardiomyocytes induced by hydrogen dioxide. Methods: Male guinea pigs were divided randomly into two groups (n = 10): intermittent hypoxia gtoup(IHH), and control group( non-IHH). The IHH guinea pigs were exposed to a simulated 5 000 m high altitude and hypoxia in hypobaric chamber for 28 d, 6 h/d. The control guinea pigs were kept in tbe same environment as IHH except hypoxia exposure. Cardiornyocytes were enzymabcally isolated from left ventricle of non-CIHH or CIHH guinea pigs. The contractile was assessed in guinea pigs by a video-based motion edge-detection system. The contents and activities of malondialdehydeC MDA), lactatdehydrogenase(IDH) and anboxidant enzymes were evaluated by using biochemical methods. Results: ①Hydrogen peroxide could induce contractile and diastol dysfunction, the latent period was longer in IHH car-diacmyocytes. ②After hydrogen peroxide(300 μmol/L, 10 min) perfusion, LDH and MDA contents in supernatant increased significantly in non-IHH and CIHH cardiomyocytes (P<0.01), Whereas the contents of MDA and LDH in IHH cardiornyocytes were lower than those in non-IHH cardiomyocytes ( P < 0.01). ③ The activities of superoxide dismutase (SOD) and catalase (CAT) were significantly increased in the myocardium of IHH guinea pigs, after hydrogen peroxide (300 μmol/L, 10 min) perfusion, SOD and CAT activities decreased significantly in non-MH and CIHH cardiomyocytes (p<0.01), whereas the activities of SOD and CAT in CIHH cardiomyocytes were still higher than those in non-IHH cardiomyocytes. Conclusion: Dffl had a protective effect on cardiomyocytes injury induced by hydrogen peroxide, which might relate with its antioxidation effects.%目的:观察慢性间歇性低压低氧对过氧化氢所致心肌细胞损伤的保护作用及其机制.方法:雄性豚鼠20只,随机分为两组(n=10):对照组(non-IHH)、低氧组(IHH).低氧

  11. Saffron extracts alleviate cardiomyocytes injury induced by doxorubicin and ischemia-reperfusion in vitro.

    Science.gov (United States)

    Chahine, Nathalie; Nader, Moni; Duca, Laurent; Martiny, Laurent; Chahine, Ramez

    2016-01-01

    Doxorubicin (DOX), a highly active chemotherapeutic drug, faces limitations in clinical application due to severe cardiotoxic effects (mainly through increased oxidative stress). Therefore, its effect is exacerbated in subjects with ischemic heart disease. We have recently reported that saffron extract (SAF), a natural compound mainly consisting of safranal and corcins, exerts a protective effect against DOX oxidative cytotoxicity in isolated rabbit hearts. Here, we aimed to investigate whether SAF exerts cardioprotection against combined ischemia-reperfusion (I/R) and DOX toxicity in H9c2 cardiomyocytes. H9c2 were subjected to simulated I/R, with or without DOX treatment at reperfusion, in the presence or absence of SAF prior to ischemia or at reperfusion. We evaluated the effects of these treatments by MTT, LDH and western blot analysis. Apoptosis was assessed by Hoechst 33258 staining, tetramethyl rhodamine methyl ester fluorescence and caspase activity. The results showed that I/R and DOX significantly decreased cardiomyocytes viability, inhibited reperfusion injury salvage kinase cardioprotective pathway, reduced contractile proteins (α-Actinine, Troponine C and MLC), increased caspase-3 expression and induced loss of mitochondrial membrane potential. These effects were remarkably inhibited by treatment with SAF (10 μg/mL) at reperfusion. SAF activated AKT/P70S6K and ERK1/2, restored contractile proteins expression, inhibited mitochondrial permeability transition pore and decreased caspase-3 activity. In conclusion, our findings indicate that SAF treatment exerted cardioprotection against I/R and DOX toxicity by reducing oxidative stress (LDH assay). Thereby, SAF offers a potential novel antioxidant therapeutic strategy to counteract I/R and DOX cardiotoxicity, paving the way for future clinical trials. PMID:25885550

  12. Picroside Ⅱ inhibits hypoxia/reoxygenation-induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in reactive oxygen species production.

    Science.gov (United States)

    Li, Jian-Zhe; Yu, Shu-Yi; Mo, Dan; Tang, Xiu-Neng; Shao, Qing-Rui

    2015-02-01

    Reactive oxygen species (ROS)‑induced mitochondrial dysfunction plays an important role in cardiomyocyte apoptosis during myocardial ischemia/reperfusion (I/R) injury. Picroside Ⅱ, isolated from Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been reported to protect cardiomyocytes from hypoxia/reoxygenation (H/R)‑induced apoptosis, but the exact mechanism is not fully clear. The aim of the present study was to explore the protective effects of picroside Ⅱ on H/R‑induced cardiomyocyte apoptosis and the underlying mechanism. In the H9c2 rat cardiomyocyte cell line, picroside Ⅱ (100 µg/ml) was added for 48 h prior to H/R. The results showed that picroside Ⅱ markedly inhibited H/R‑induced cardiomyocyte apoptosis. In addition, picroside Ⅱ was also able to decrease the opening degree of mitochondrial permeability transition pore (mPTP), increase the mitochondrial membrane potential, inhibit cytochrome c release from mitochondria to cytosol and downregulate caspase‑3 expression and activity concomitantly with the decreased ROS production. These results suggested that picroside Ⅱ inhibited H/R‑induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in ROS production.

  13. Cardiomyocytes from human pluripotent stem cells: From laboratory curiosity to industrial biomedical platform.

    Science.gov (United States)

    Denning, Chris; Borgdorff, Viola; Crutchley, James; Firth, Karl S A; George, Vinoj; Kalra, Spandan; Kondrashov, Alexander; Hoang, Minh Duc; Mosqueira, Diogo; Patel, Asha; Prodanov, Ljupcho; Rajamohan, Divya; Skarnes, William C; Smith, James G W; Young, Lorraine E

    2016-07-01

    Cardiomyocytes from human pluripotent stem cells (hPSCs-CMs) could revolutionise biomedicine. Global burden of heart failure will soon reach USD $90bn, while unexpected cardiotoxicity underlies 28% of drug withdrawals. Advances in hPSC isolation, Cas9/CRISPR genome engineering and hPSC-CM differentiation have improved patient care, progressed drugs to clinic and opened a new era in safety pharmacology. Nevertheless, predictive cardiotoxicity using hPSC-CMs contrasts from failure to almost total success. Since this likely relates to cell immaturity, efforts are underway to use biochemical and biophysical cues to improve many of the ~30 structural and functional properties of hPSC-CMs towards those seen in adult CMs. Other developments needed for widespread hPSC-CM utility include subtype specification, cost reduction of large scale differentiation and elimination of the phenotyping bottleneck. This review will consider these factors in the evolution of hPSC-CM technologies, as well as their integration into high content industrial platforms that assess structure, mitochondrial function, electrophysiology, calcium transients and contractility. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. PMID:26524115

  14. Cardiomyocytes from human pluripotent stem cells: From laboratory curiosity to industrial biomedical platform.

    Science.gov (United States)

    Denning, Chris; Borgdorff, Viola; Crutchley, James; Firth, Karl S A; George, Vinoj; Kalra, Spandan; Kondrashov, Alexander; Hoang, Minh Duc; Mosqueira, Diogo; Patel, Asha; Prodanov, Ljupcho; Rajamohan, Divya; Skarnes, William C; Smith, James G W; Young, Lorraine E

    2016-07-01

    Cardiomyocytes from human pluripotent stem cells (hPSCs-CMs) could revolutionise biomedicine. Global burden of heart failure will soon reach USD $90bn, while unexpected cardiotoxicity underlies 28% of drug withdrawals. Advances in hPSC isolation, Cas9/CRISPR genome engineering and hPSC-CM differentiation have improved patient care, progressed drugs to clinic and opened a new era in safety pharmacology. Nevertheless, predictive cardiotoxicity using hPSC-CMs contrasts from failure to almost total success. Since this likely relates to cell immaturity, efforts are underway to use biochemical and biophysical cues to improve many of the ~30 structural and functional properties of hPSC-CMs towards those seen in adult CMs. Other developments needed for widespread hPSC-CM utility include subtype specification, cost reduction of large scale differentiation and elimination of the phenotyping bottleneck. This review will consider these factors in the evolution of hPSC-CM technologies, as well as their integration into high content industrial platforms that assess structure, mitochondrial function, electrophysiology, calcium transients and contractility. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  15. Coupling primary and stem cell-derived cardiomyocytes in an in vitro model of cardiac cell therapy.

    Science.gov (United States)

    Aratyn-Schaus, Yvonne; Pasqualini, Francesco S; Yuan, Hongyan; McCain, Megan L; Ye, George J C; Sheehy, Sean P; Campbell, Patrick H; Parker, Kevin Kit

    2016-02-15

    The efficacy of cardiac cell therapy depends on the integration of existing and newly formed cardiomyocytes. Here, we developed a minimal in vitro model of this interface by engineering two cell microtissues (μtissues) containing mouse cardiomyocytes, representing spared myocardium after injury, and cardiomyocytes generated from embryonic and induced pluripotent stem cells, to model newly formed cells. We demonstrated that weaker stem cell-derived myocytes coupled with stronger myocytes to support synchronous contraction, but this arrangement required focal adhesion-like structures near the cell-cell junction that degrade force transmission between cells. Moreover, we developed a computational model of μtissue mechanics to demonstrate that a reduction in isometric tension is sufficient to impair force transmission across the cell-cell boundary. Together, our in vitro and in silico results suggest that mechanotransductive mechanisms may contribute to the modest functional benefits observed in cell-therapy studies by regulating the amount of contractile force effectively transmitted at the junction between newly formed and spared myocytes. PMID:26858266

  16. Astragaloside IV inhibits doxorubicin-induced cardiomyocyte apoptosis mediated by mitochondrial apoptotic pathway via activating the PI3K/Akt pathway.

    Science.gov (United States)

    Jia, Yuanyuan; Zuo, Daiying; Li, Zengqiang; Liu, Hanmo; Dai, Zhengning; Cai, Jiayi; Pang, Lili; Wu, Yingliang

    2014-01-01

    Doxorubicin (DOX) is a widely used antitumor drug whose application is seriously limited by its cardiotoxicity. Mitochondria-mediated cardiomyocyte apoptosis plays a critical role in DOX-induced cardiotoxicity (DIC). The aim of the present study was to investigate the protective effect of astragaloside IV (3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-cycloastragenol, AS-IV), a pure saponin isolated from Astragalus membranaceus, against DOX-induced cardiomyocyte apoptosis in primary cultured neonatal rat cardiomyocytes. Immunocytochemistry and Microculture Tetrazolium (MTT) assays showed that AS-IV significantly reduced DOX-induced cardiomyocyte loss. Additionally, AS-IV markedly ameliorated DOX-caused cardiomyocyte dysfunction via restoring the beating cell ratio and beating rate in cardiomyocytes. Furthermore, AS-IV substantially reduced the mitochondrial reactive oxygen species (ROS) production and lactate dehydrogenase (LDH), creatine kinase-MB isoenzyme (CK-MB) and cytochrome c (CytC) release, and restored the reduced ATP level, succinate dehydrogenase (SDH) and ATP synthase activities induced by DOX, suggesting that AS-IV significantly attenuated DOX-induced mitochondrial damage and dysfunction. It was further observed that DOX-induced cardiomyocyte apoptosis, as qualitatively evaluated by Hoechst 33258 staining and accurately quantified by flow cytometry, was markedly inhibited by AS-IV. Western blot analysis manifested that AS-IV significantly inhibited the activation of mitochondrial apoptotic pathway (MAP) via inducing the phosphorylation of Akt and Bad. Furthermore, phosphatidylinositol 3-kinase (PI3K) inhibitor 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) remarkably inhibited the anti-apoptotic effect of AS-IV. Moreover, AS-IV didn't compromise the antitumor activity of DOX. Taken together, our findings indicate that AS-IV ameliorates DIC, and this beneficial effect appears to be dependent on the activation of the PI3K

  17. Mesenchymal stem cells from rat olfactory bulbs can differentiate into cells with cardiomyocyte characteristics.

    Science.gov (United States)

    Huang, Yuahn-Sieh; Li, I-Hsun; Chueh, Sheau-Huei; Hueng, Dueng-Yuan; Tai, Ming-Cheng; Liang, Chang-Min; Lien, Shiu-Bii; Sytwu, Huey-Kang; Ma, Kuo-Hsing

    2015-12-01

    Mesenchymal stromal/stem cells (MSCs) are widely distributed in different tissues such as bone marrow, adipose tissues, peripheral blood, umbilical cord and amnionic fluid. Recently, MSC-like cells were also found to exist in rat olfactory bulb and are capable of inducing differentiation into mesenchymal lineages - osteocytes, chondrocytes and adipocytes. However, whether these cells can differentiate into myocardial cells is not known. In this study, we examined whether olfactory bulb-derived MSCs could differentiate into myocardial cells in vitro. Fibroblast-like cells isolated from the olfactory bulb of neonatal rats were grown under four conditions: no treatment; in the presence of growth factors (neuregulin-1, bFGF and forskolin); co-cultured with cardiomyocytes; and co-cultured with cardiomyocytes plus neuregulin-1, bFGF and forskolin. Cell differentiation into myocardial cells was monitored by RT-PCR, light microscopy immunofluorescence, western blot analysis and contractile response to pharmacological treatments. The isolated olfactory bulb-derived fibroblast-like cells expressed CD29, CD44, CD90, CD105, CD166 but not CD34 and CD45, consistent with the characteristics of MSCs. Long cylindical cells that spontaneously contracted were only observed following 7 days of co-culture of MSCs with rat cardiomyocytes plus neuregulin-1, bFGF and forskolin. RT-PCR and western blot analysis indicated that the cylindrical cells expressed myocardial markers, such as Nkx2.5, GATA4, sarcomeric α-actinin, cardiac troponin I, cardiac myosin heavy chain, atrial natriuretic peptide and connexin 43. They also contained sarcomeres and gap junction and were sensitive to pharmacological treatments (adrenal and cholinergic agonists and antagonists). These findings indicate that rat olfactory bulb-derived fibroblast-like cells with MSC characteristics can differentiate into myocardial-like cells.

  18. Cardiomyocyte Marker Expression in Mouse Embryonic Fibroblasts by Cell-Free Cardiomyocyte Extract and Epigenetic Manipulation

    OpenAIRE

    Tahereh Talaei-Khozani; Fatemeh Heidari; Tahereh Esmaeilpour; Zahra Vojdani; Zohrah Mostafavi-Pour; Leili Rohani

    2014-01-01

    Background: The regenerative capacity of the mammalian heart is quite limited. Recent reports have focused on reprogramming mesenchymal stem cells into cardiomyocytes. We investigated whether fibroblasts could transdifferentiate into myocardium. Methods: Mouse embryonic fibroblasts were treated with Trichostatin A (TSA) and 5-Aza-2-Deoxycytidine (5-aza-dC). The treated cells were permeabilized with streptolysin O and exposed to the mouse cardiomyocyte extract and cultured for 1, 10, and 21...

  19. Cardiomyocyte Marker Expression in Mouse Embryonic Fibroblasts by Cell-Free Cardiomyocyte Extract and Epigenetic Manipulation

    Directory of Open Access Journals (Sweden)

    Tahereh Talaei-Khozani

    2014-03-01

    Full Text Available Background: The regenerative capacity of the mammalian heart is quite limited. Recent reports have focused on reprogramming mesenchymal stem cells into cardiomyocytes. We investigated whether fibroblasts could transdifferentiate into myocardium. Methods: Mouse embryonic fibroblasts were treated with Trichostatin A (TSA and 5-Aza-2-Deoxycytidine (5-aza-dC. The treated cells were permeabilized with streptolysin O and exposed to the mouse cardiomyocyte extract and cultured for 1, 10, and 21 days. Cardiomyocyte markers were detected by immunohistochemistry. Alkaline phosphatase activity and OCT4 were also detected in cells treated by chromatin-modifying agents. Results: The cells exposed to a combination of 5-aza-dC and TSA and permeabilized in the presence of the cardiomyocyte extract showed morphological changes. The cells were unable to express cardiomyocyte markers after 24 h. Immunocytochemical assays showed a notable degree of myosin heavy chain and α-actinin expressions after 10 days. The expression of the natriuretic factor and troponin T occurred after 21 days in these cells. The cells exposed to chromatin-modifying agents also expressed cardiomyocyte markers; however, the proportion of reprogrammed cells was clearly smaller than that in the cultures exposed to 5-aza-dC , TSA, and extract. Conclusion: It seems that the fibroblasts were able to eliminate the previous epigenetic markers and form new ones according to the factors existing in the extract. Since no beating was observed, at least up to 21 days, the cells may need an appropriate extracellular matrix for their function.

  20. Modeling and analysis of bio-syncretic micro-swimmers for cardiomyocyte-based actuation.

    Science.gov (United States)

    Zhang, Chuang; Wang, Jingyi; Wang, Wenxue; Xi, Ning; Wang, Yuechao; Liu, Lianqing

    2016-08-22

    Along with sensation and intelligence, actuation is one of the most important factors in the development of conventional robots. Many novel achievements have been made regarding bio-based actuators to solve the challenges of conventional actuation. However, few studies have focused on methods for controlling the movement performance of bio-syncretic robots by designing robotic structures and programming actuation bio-entities. In this paper, a theoretical model was derived considering kinematics and hydromechanics to describe the dynamics of a dolphin-shaped microstructure and to control the bio-syncretic swimmer movement by establishing the relationships between the swimming velocity of the bio-swimmer, the cell seeding concentration and the cell contractility. The proposed theoretical model was then verified with the fabricated biomimetic swimmer prototype actuated by equivalent external magnetism replacing the bio-entity force based on the study of living, beating cardiomyocyte contractility. This work can improve the development of bio-syncretic robots with an approach to preplanning the seeding concentration of cells for controlling the movement velocity of microstructures, and is also meaningful for biomimetic robots, medical treatments and interventional therapy applications.

  1. Spontaneous actin dynamics in contractile rings

    Science.gov (United States)

    Kruse, Karsten; Wollrab, Viktoria; Thiagarajan, Raghavan; Wald, Anne; Riveline, Daniel

    Networks of polymerizing actin filaments are known to be capable to self-organize into a variety of structures. For example, spontaneous actin polymerization waves have been observed in living cells in a number of circumstances, notably, in crawling neutrophils and slime molds. During later stages of cell division, they can also spontaneously form a contractile ring that will eventually cleave the cell into two daughter cells. We present a framework for describing networks of polymerizing actin filaments, where assembly is regulated by various proteins. It can also include the effects of molecular motors. We show that the molecular processes driven by these proteins can generate various structures that have been observed in contractile rings of fission yeast and mammalian cells. We discuss a possible functional role of each of these patterns. The work was supported by Agence Nationale de la Recherche, France, (ANR-10-LABX-0030-INRT) and by Deutsche Forschungsgemeinschaft through SFB1027.

  2. Right atrial contractile dynamics are impaired in patients with postcapillary pulmonary hypertension

    Science.gov (United States)

    Bening, Constanze; Leyh, Rainer

    2016-01-01

    Left ventricular (LV) dysfunction in conjunction with postcapillary pulmonary hypertension (PH) is frequently associated with right ventricular (RV) dysfunction, determining the patient prognosis. Compensatory mechanisms for RV dysfunction have not been previously evaluated in detail. Since calcium dependent right atrial (RA) dynamics are a surrogate for RA contractile properties, the present study examined the calcium dependency of RA tissue obtained from patients with or without postcapillary PH. In total, 15 patients with PH (PH group; mean age, 70.7±7.2 years) and 10 patients without postcapillary PH (non-PH group; mean age, 55.7±11.8 years) who were scheduled to undergo elective left heart valve surgery were included in the current study. Calcium concentration (pCa; shown as the negative log10) against force curves were generated, while LV and RV function was evaluated by echocardiography. Echocardiography data revealed a significantly reduced LV function in the PH group, while the RV function was preserved in the two groups, precluding overt RV dysfunction. In the PH group, significantly reduced force values were detected at high pCa values when compared with the non-PH group force, indicating impaired RA function. Furthermore, reduced calcium sensitivity was observed (which was determined as the pCa at half maximal activation) in the PH group, and the presence of a compensatory mechanism for reduced force capacity was hypothesized. In conclusion, the preliminary results of the current study showed impaired RA contractile properties in postcapillary hypertension with preserved RV function. The diminished RA compensatory mechanisms may lead to accelerated RV dysfunction in the clinical course of postcapillary PH.

  3. Analysis of cardiomyocyte movement in the developing murine heart

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Hisayuki [Department of Cardiology, Keio University School of Medicine, Tokyo (Japan); Yuasa, Shinsuke, E-mail: yuasa@a8.keio.jp [Department of Cardiology, Keio University School of Medicine, Tokyo (Japan); Tabata, Hidenori [Department of Anatomy, Keio University School of Medicine, Tokyo (Japan); Tohyama, Shugo; Seki, Tomohisa; Egashira, Toru; Hayashiji, Nozomi; Hattori, Fumiyuki; Kusumoto, Dai; Kunitomi, Akira; Takei, Makoto; Kashimura, Shin; Yozu, Gakuto; Shimojima, Masaya; Motoda, Chikaaki; Muraoka, Naoto [Department of Cardiology, Keio University School of Medicine, Tokyo (Japan); Nakajima, Kazunori [Department of Anatomy, Keio University School of Medicine, Tokyo (Japan); Sakaue-Sawano, Asako; Miyawaki, Atsushi [Life Function and Dynamics, ERATO, JST, 2-1 Hirosawa, Wako-city, Saitama 351-0198 (Japan); Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198 (Japan); Fukuda, Keiichi [Department of Cardiology, Keio University School of Medicine, Tokyo (Japan)

    2015-09-04

    The precise assemblage of several types of cardiac precursors controls heart organogenesis. The cardiac precursors show dynamic movement during early development and then form the complicated heart structure. However, cardiomyocyte movements inside the newly organized mammalian heart remain unclear. We previously established the method of ex vivo time-lapse imaging of the murine heart to study cardiomyocyte behavior by using the Fucci (fluorescent ubiquitination-based cell cycle indicator) system, which can effectively label individual G1, S/G2/M, and G1/S-transition phase nuclei in living cardiomyocytes as red, green, and yellow, respectively. Global analysis of gene expression in Fucci green positive ventricular cardiomyocytes confirmed that cell cycle regulatory genes expressed in G1/S, S, G2/M, and M phase transitions were upregulated. Interestingly, pathway analysis revealed that many genes related to the cell cycle were significantly upregulated in the Fucci green positive ventricular cardiomyocytes, while only a small number of genes related to cell motility were upregulated. Time-lapse imaging showed that murine proliferating cardiomyocytes did not exhibit dynamic movement inside the heart, but stayed on site after entering the cell cycle. - Highlights: • We directly visualized cardiomyocyte movement inside the developing murine heart. • Cell cycle related genes were upregulated in the proliferating cardiomyocytes. • Time-lapse imaging revealed that proliferating murine cardiomyocytes stayed in place. • Murine ventricular cardiomyocytes proliferate on site during development.

  4. Analysis of cardiomyocyte movement in the developing murine heart

    International Nuclear Information System (INIS)

    The precise assemblage of several types of cardiac precursors controls heart organogenesis. The cardiac precursors show dynamic movement during early development and then form the complicated heart structure. However, cardiomyocyte movements inside the newly organized mammalian heart remain unclear. We previously established the method of ex vivo time-lapse imaging of the murine heart to study cardiomyocyte behavior by using the Fucci (fluorescent ubiquitination-based cell cycle indicator) system, which can effectively label individual G1, S/G2/M, and G1/S-transition phase nuclei in living cardiomyocytes as red, green, and yellow, respectively. Global analysis of gene expression in Fucci green positive ventricular cardiomyocytes confirmed that cell cycle regulatory genes expressed in G1/S, S, G2/M, and M phase transitions were upregulated. Interestingly, pathway analysis revealed that many genes related to the cell cycle were significantly upregulated in the Fucci green positive ventricular cardiomyocytes, while only a small number of genes related to cell motility were upregulated. Time-lapse imaging showed that murine proliferating cardiomyocytes did not exhibit dynamic movement inside the heart, but stayed on site after entering the cell cycle. - Highlights: • We directly visualized cardiomyocyte movement inside the developing murine heart. • Cell cycle related genes were upregulated in the proliferating cardiomyocytes. • Time-lapse imaging revealed that proliferating murine cardiomyocytes stayed in place. • Murine ventricular cardiomyocytes proliferate on site during development

  5. Acute pergolide exposure stiffens engineered valve interstitial cell tissues and reduces contractility in vitro.

    Science.gov (United States)

    Capulli, Andrew K; MacQueen, Luke A; O'Connor, Blakely B; Dauth, Stephanie; Parker, Kevin Kit

    2016-01-01

    Medications based on ergoline-derived dopamine and serotonin agonists are associated with off-target toxicities that include valvular heart disease (VHD). Reports of drug-induced VHD resulted in the withdrawal of appetite suppressants containing fenfluramine and phentermine from the US market in 1997 and pergolide, a Parkinson's disease medication, in 2007. Recent evidence suggests that serotonin receptor activity affected by these medications modulates cardiac valve interstitial cell activation and subsequent valvular remodeling, which can lead to cardiac valve fibrosis and dysfunction similar to that seen in carcinoid heart disease. Failure to identify these risks prior to market and continued use of similar drugs reaffirm the need to improve preclinical evaluation of drug-induced VHD. Here, we present two complimentary assays to measure stiffness and contractile stresses generated by engineered valvular tissues in vitro. As a case study, we measured the effects of acute (24 h) pergolide exposure to engineered porcine aortic valve interstitial cell (AVIC) tissues. Pergolide exposure led to increased tissue stiffness, but it decreased both basal and active contractile tone stresses generated by AVIC tissues. Pergolide exposure also disrupted AVIC tissue organization (i.e., tissue anisotropy), suggesting that the mechanical properties and contractile functionality of these tissues are governed by their ability to maintain their structure. We expect further use of these assays to identify off-target drug effects that alter the phenotypic balance of AVICs, disrupt their ability to maintain mechanical homeostasis, and lead to VHD. PMID:27174867

  6. Absence of thrombospondin-2 increases cardiomyocyte damage and matrix disruption in doxorubicin-induced cardiomyopathy.

    Science.gov (United States)

    van Almen, Geert C; Swinnen, Melissa; Carai, Paolo; Verhesen, Wouter; Cleutjens, Jack P M; D'hooge, Jan; Verheyen, Fons K; Pinto, Yigal M; Schroen, Blanche; Carmeliet, Peter; Heymans, Stephane

    2011-09-01

    Clinical use of the antineoplastic agent doxorubicin (DOX) is limited by its cardiomyocyte toxicity. Attempts to decrease cardiomyocyte injury showed promising results in vitro, but failed to reduce the adverse effects of DOX in vivo, suggesting that other mechanisms contribute to its cardiotoxicity as well. Evidence that DOX also induces cardiac injury by compromising extracellular matrix integrity is lacking. The matricellular protein thrombospondin-2 (TSP-2) is known for its matrix-preserving function, and for modulating cellular function. Here, we investigated whether TSP-2 modulates the process of doxorubicin-induced cardiomyopathy (DOX-CMP). TSP-2-knockout (TSP-2-KO) and wild-type (WT) mice were treated with DOX (2 mg/kg/week) for 12 weeks to induce DOX-CMP. Mortality was significantly increased in TSP-2-KO compared to WT mice. Surviving DOX-treated TSP-2-KO mice had depressed cardiac function compared to WT animals, accompanied by increased cardiomyocyte apoptosis and matrix damage. Enhanced myocyte damage in the absence of TSP-2 was associated with impaired activation of the Akt signaling pathway in TSP-2-KO compared to WT. The absence of TSP-2, in vivo and in vitro, reduced Akt activation both under non-treated conditions and after DOX. Importantly, inhibition of Akt phosphorylation in cardiomyocytes significantly reduced TSP-2 expression, unveiling a unique feedback loop between Akt and TSP-2. Finally, enhanced matrix disruption in DOX-treated TSP-2-KO hearts went along with increased matrix metalloproteinase-2 levels. Taken together, this study is the first to provide evidence for the implication of the matrix element TSP-2 in protecting against DOX-induced cardiac injury and dysfunction. PMID:21624372

  7. Cell stiffness, contractile stress and the role of extracellular matrix

    Science.gov (United States)

    An, Steven S.; Kim, Jina; Ahn, Kwangmi; Trepat, Xavier; Drake, Kenneth J.; Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne; Fredberg, Jeffrey J.; Biswal, Shyam

    2010-01-01

    Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses. PMID:19327344

  8. Cell stiffness, contractile stress and the role of extracellular matrix

    Energy Technology Data Exchange (ETDEWEB)

    An, Steven S., E-mail: san@jhsph.edu [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Kim, Jina [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Ahn, Kwangmi [Division of Biostatistics, Penn State College of Medicine, Hershey, PA 17033 (United States); Trepat, Xavier [CIBER, Enfermedades Respiratorias, 07110 Bunyola (Spain); Drake, Kenneth J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Fredberg, Jeffrey J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Biswal, Shyam [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205 (United States)

    2009-05-15

    Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses.

  9. Elastic interactions synchronize beating in cardiomyocytes.

    Science.gov (United States)

    Cohen, Ohad; Safran, Samuel A

    2016-07-13

    Motivated by recent experimental results, we study theoretically the synchronization of the beating phase and frequency of two nearby cardiomyocyte cells. Each cell is represented as an oscillating force dipole in an infinite, viscoelastic medium and the propagation of the elastic signal within the medium is predicted. We examine the steady-state beating of two nearby cells, and show that elastic interactions result in forces that synchronize the phase and frequency of beating in a manner that depends on their mutual orientation. The theory predicts both in-phase and anti-phase steady-state beating depending on the relative cell orientations, as well as how synchronized beating varies with substrate elasticity and the inter-cell distance. These results suggest how mechanics plays a role in cardiac efficiency, and may be relevant for the design of cardiomyocyte based micro devices and other biomedical applications. PMID:27352146

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  1. File list: InP.CDV.50.AllAg.Cardiomyocytes [Chip-atlas[Archive

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  5. Regulation of tissue morphodynamics: an important role for actomyosin contractility

    Science.gov (United States)

    Siedlik, Michael J.; Nelson, Celeste M.

    2015-01-01

    Forces arising from contractile actomyosin filaments help shape tissue form during morphogenesis. Developmental events that result from actomyosin contractility include tissue elongation, bending, budding, and collective migration. Here, we highlight recent insights into these morphogenetic processes from the perspective of actomyosin contractility as a key regulator. Emphasis is placed on a range of results obtained through live imaging, culture, and computational methods. Combining these approaches in the future has the potential to generate a robust, quantitative understanding of tissue morphodynamics. PMID:25748251

  6. Metabolic changes in cardiomyocytes during sepsis

    OpenAIRE

    Douglas, James J; Keith R Walley

    2013-01-01

    Different types of shock induce distinct metabolic changes. The myocardium at rest utilizes free fatty acids as its primary energy source, a mechanism that changes to aerobic glycolysis during sepsis and is in contrast to hemorrhagic shock. The immune system also uses this mechanism, changing its substrate utilization to activate innate and adaptive cells. Cardiomyocytes share a number of features similar to antigen-presenting cells and may use this mechanism to augment the immune response at...

  7. Data on the gene expression of cardiomyocyte exposed to hypothermia.

    Science.gov (United States)

    Zhang, Jian; Xue, Xiaodong; Xu, Yinli; Zhang, Yuji; Li, Zhi; Wang, Huishan

    2016-09-01

    Hypothermia is widely used in neurosurgery and cardiac surgeries. However, little is known about the underlying molecular mechanisms. We previously reported that the transcriptome responses of cardiomyocyte exposed to hypothermia, "The transcriptome responses of cardiomyocyte exposed to hypothermia" [4]. Herein, we provide the hypothermia inhibited proliferation of cardiomyocyte cells in vitro and the details of transcription factors in regulation of differentially expressed genes. PMID:27274530

  8. Impaired contractility and remodeling of the upper gastrointestinal tract in diabetes mellitus type-1

    Institute of Scientific and Technical Information of China (English)

    Jens Brφndum Frφkjaer; Sφren Due Andersen; Niels Ejskjaer; Peter Funch-Jensen; Asbjφrn Mohr Drewes; Hans Gregersen

    2007-01-01

    AIM: To investigate that both the neuronal function of the contractile system and structural apparatus of the gastrointestinal tract are affected in patients with longstanding diabetes and auto mic neuropathy.METHODS: The evoked esophageal and duodenal contractile activity to standardized bag distension was assessed using a specialized ultrasound-based probe. Twelve type-1 diabetic patients with autonomic neuropathy and severe gastrointestinal symptoms and 12 healthy controls were studied. The geometry and biomechanical parameters (strain, tension/stress, and stiffness) were assessed.RESULTS: The diabetic patients had increased frequency of distension-induced contractions (6.0 ±0.6 vs 3.3 ± 0.5, P < 0.001). This increased reactivity was correlated with the duration of the disease (P =0.009). Impaired coordination of the contractile activity in diabetic patients was demonstrated as imbalance between the time required to evoke the first contraction at the distension site and proximal to it (1.5 ± 0.6 vs 0.5± 0.1, P = 0.03). The esophageal wall and especially the mucosa-submucosa layer had increased thickness in the patients (P < 0.001), and the longitudinal and radial compressive stretch was less in diabetics (P <0.001). The esophageal and duodenal wall stiffness and circumferential deformation induced by the distensions were not affected in the patients (all P > 0.14).CONCLUSION: The impaired contractile activity with an imbalance in the distension-induced contractions likely reflects neuronal abnormalities due to autonomic neuropathy. However, structural changes and remodeling of the gastrointestinal tract are also evident and may add to the neuronal changes. This may contribute to the pathophysiology of diabetic gut dysfunction and impact on future management of diabetic patients with gastrointestinal symptoms.

  9. Altered myocardial metabolic adaptation to increased fatty acid availability in cardiomyocyte-specific CLOCK mutant mice.

    Science.gov (United States)

    Peliciari-Garcia, Rodrigo A; Goel, Mehak; Aristorenas, Jonathan A; Shah, Krishna; He, Lan; Yang, Qinglin; Shalev, Anath; Bailey, Shannon M; Prabhu, Sumanth D; Chatham, John C; Gamble, Karen L; Young, Martin E

    2016-10-01

    A mismatch between fatty acid availability and utilization leads to cellular/organ dysfunction during cardiometabolic disease states (e.g., obesity, diabetes mellitus). This can precipitate cardiac dysfunction. The heart adapts to increased fatty acid availability at transcriptional, translational, post-translational and metabolic levels, thereby attenuating cardiomyopathy development. We have previously reported that the cardiomyocyte circadian clock regulates transcriptional responsiveness of the heart to acute increases in fatty acid availability (e.g., short-term fasting). The purpose of the present study was to investigate whether the cardiomyocyte circadian clock plays a role in adaptation of the heart to chronic elevations in fatty acid availability. Fatty acid availability was increased in cardiomyocyte-specific CLOCK mutant (CCM) and wild-type (WT) littermate mice for 9weeks in time-of-day-independent (streptozotocin (STZ) induced diabetes) and dependent (high fat diet meal feeding) manners. Indices of myocardial metabolic adaptation (e.g., substrate reliance perturbations) to STZ-induced diabetes and high fat meal feeding were found to be dependent on genotype. Various transcriptional and post-translational mechanisms were investigated, revealing that Cte1 mRNA induction in the heart during STZ-induced diabetes is attenuated in CCM hearts. At the functional level, time-of-day-dependent high fat meal feeding tended to influence cardiac function to a greater extent in WT versus CCM mice. Collectively, these data suggest that CLOCK (a circadian clock component) is important for metabolic adaption of the heart to prolonged elevations in fatty acid availability. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk. PMID:26721420

  10. Molecular Model of the Contractile Ring

    CERN Document Server

    Biron, D; Tlusty, Tsvi; Moses, Elisha; 10.1103/PhysRevLett.95.098102

    2010-01-01

    We present a model for the actin contractile ring of adherent animal cells. The model suggests that the actin concentration within the ring and consequently the power that the ring exerts both increase during contraction. We demonstrate the crucial role of actin polymerization and depolymerization throughout cytokinesis, and the dominance of viscous dissipation in the dynamics. The physical origin of two phases in cytokinesis dynamics ("biphasic cytokinesis") follows from a limitation on the actin density. The model is consistent with a wide range of measurements of the midzone of dividing animal cells.

  11. Inhibition of NAPDH Oxidase 2 (NOX2 Prevents Oxidative Stress and Mitochondrial Abnormalities Caused by Saturated Fat in Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Leroy C Joseph

    Full Text Available Obesity and high saturated fat intake increase the risk of heart failure and arrhythmias. The molecular mechanisms are poorly understood. We hypothesized that physiologic levels of saturated fat could increase mitochondrial reactive oxygen species (ROS in cardiomyocytes, leading to abnormalities of calcium homeostasis and mitochondrial function. We investigated the effect of saturated fat on mitochondrial function and calcium homeostasis in isolated ventricular myocytes. The saturated fatty acid palmitate causes a decrease in mitochondrial respiration in cardiomyocytes. Palmitate, but not the monounsaturated fatty acid oleate, causes an increase in both total cellular ROS and mitochondrial ROS. Palmitate depolarizes the mitochondrial inner membrane and causes mitochondrial calcium overload by increasing sarcoplasmic reticulum calcium leak. Inhibitors of PKC or NOX2 prevent mitochondrial dysfunction and the increase in ROS, demonstrating that PKC-NOX2 activation is also required for amplification of palmitate induced-ROS. Cardiomyocytes from mice with genetic deletion of NOX2 do not have palmitate-induced ROS or mitochondrial dysfunction. We conclude that palmitate induces mitochondrial ROS that is amplified by NOX2, causing greater mitochondrial ROS generation and partial depolarization of the mitochondrial inner membrane. The abnormal sarcoplasmic reticulum calcium leak caused by palmitate could promote arrhythmia and heart failure. NOX2 inhibition is a potential therapy for heart disease caused by diabetes or obesity.

  12. Negative Modulation of NO for Diaphragmatic Contractile Reduction Induced by Sepsis and Restraint Position

    Institute of Scientific and Technical Information of China (English)

    XIANG Jian; GUAN Su-dong; SONG Xiang-he; WANG Hui-yun; GU Zhen-yong

    2014-01-01

    In practice of forensic medicine, potential disease can be associated with fatal asphyxia in re-straint position. Research has demonstrated that nitric oxide (NO) and nitric oxide synthase (NOS) are plentifully distributed in skeletal muscle, contributing to the regulation of contractile and relaxation. In the current study, respiratory functions, indices of diaphragmatic biomechanical functions ex vivo, as well as NO levels in serum, the expressions of diaphragmatic inducible NOS (iNOS) mRNA, and the effects of L-NNA on contractility of the diaphragm were observed in sepsis induced by cecal ligation and punc-ture (CLP) under the condition of restraint position. The results showed that in the CLP12-18 h rats, respiratory dysfunctions; indices of diaphragmatic biomechanical functions (Pt, +dT/dtmax, -dT/dtmax, CT, Po, force over the full range of the force-frequency relationship and fatigue resistance ) declined progressive-ly; the NO level in serum, and iNOS mRNA expression in the diaphragm increased progressively; force increased significantly at all stimulation frequencies after L-NNA pre-incubation. Restraint position 1 h in CLP12 h rats resulted in severe respiratory dysfunctions after relative stable respiratory functions, almost all the indices of diaphragmatic biomechanical functions declined further, whereas little change took place in NO level in serum and diaphragmatic iNOS mRNA expression; and the effects of L-NNA were lack of statistical significance compared with those of CLP12 h, but differed from CLP18 h group. These results suggest that restraint position and sepsis act together in a synergistic manner to aggravate the great reduction of diaphragmatic contractility via, at least in part, the negative modulation of NO, which may contribute to the pathogenesis of positional asphyxia.

  13. Oxidative Stress in Hypertensive Patients Induces an Increased Contractility in Vein Grafts Independent of Endothelial Function

    Directory of Open Access Journals (Sweden)

    Claudio Joo Turoni

    2011-01-01

    Full Text Available Objective. To evaluate the impact of oxidative stress on vascular reactivity to vasoconstrictors and on nitric oxide (NO bioavailability in saphenous vein (SV graft with endothelial dysfunction from hypertensive patients (HT. Methods. Endothelial function, vascular reactivity, oxidative state, nitrites and NO release were studied in isolated SV rings from HT and normotensive patients (NT. Only rings with endothelial dysfunction were used. Results. HT rings presented a hyperreactivity to vasoconstrictors that was reverted by diphenylene iodonium (DPI. In NT, no effect of DPI was obtained, but Nω-nitro-L-arginine methyl ester (L-NAME increased the contractile response. NO was present in SV rings without endothelial function. Nitrites were higher in NT than in HT (1066.1 ± 86.3 pmol/mg; n=11 versus 487.8 ± 51.6; n=23; P<0.01 and inhibited by nNOS inhibitor. L-arginine reversed this effect. Antioxidant agents increased nitrites and NO contents only in HT. The anti-nNOS-stained area by immunohistochemistry was higher in NT than HT. HT showed an elevation of oxidative state. Conclusions. Extraendothelial NO counter-regulates contractility in SV. However, this action could be altered in hypertensive situations by an increased oxidative stress or a decreased ability of nNOS to produce NO. Further studies should be performed to evaluate the implication of these results in graft patency rates.

  14. Contractility Dispersion in Long QT Syndrome

    Directory of Open Access Journals (Sweden)

    MH Nikoo

    2009-09-01

    Full Text Available Background: Previous studies, using M mode echocardiography, provided unexpected evidence of a mechanical alteration in patients with long QT syndrome. The aim of this study was to evaluate entire left ventricular (LV wall motion characteristics in patients with long QT syndrome using tissue Doppler imaging. Methods: We enrolled 17 patients with congenital long QT syndrome [11 female and 6 male], aged 21 to 45 years. 10 subjects without cardiac disease were also selected as a control group. Two-dimensional tissue Doppler imaging (TDI recording of the LV was obtained from the basal and mid-segments from apical four-chamber, two-chamber, and long-axis views. ‘Myocardial Contraction Duration’ [MCD] was defined as the time from start of R wave on ECG to end of S wave on TDI. MCD was measured in the six LV wall positions: septal, anteroseptal, lateral, inferior, posterior and anterior positions.Results: LV contractility dispersion was significantly greater in long QT syndrome patients compared to control group [0.051 ± 0.011 vs. 0.016 ± 0.06; P < 0.001]. Conclusion: Our study evaluated left ventricular dispersion of contractility duration in patients with long QT syndrome. This mechanical dispersion may be a reflection of the inhomogeneity of repolarisation in the long QT syndrome.

  15. Generation of Induced Pluripotent Stem Cells From Patients With Duchenne Muscular Dystrophy and Their Induction to Cardiomyocytes.

    Science.gov (United States)

    Hashimoto, Akihito; Naito, Atsuhiko T; Lee, Jong-Kook; Kitazume-Taneike, Rika; Ito, Masamichi; Yamaguchi, Toshihiro; Nakata, Ryo; Sumida, Tomokazu; Okada, Katsuki; Nakagawa, Akito; Higo, Tomoaki; Kuramoto, Yuki; Sakai, Taku; Tominaga, Koji; Okinaga, Takeshi; Kogaki, Shigetoyo; Ozono, Keiichi; Miyagawa, Shigeru; Sawa, Yoshiki; Sakata, Yasushi; Morita, Hiroyuki; Umezawa, Akihiro; Komuro, Issei

    2016-01-01

    Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene which encodes dystrophin protein. Dystrophin defect affects cardiac muscle as well as skeletal muscle. Cardiac dysfunction is observed in all patients with DMD over 18 years of age, but there is no curative treatment for DMD cardiomyopathy. To establish novel experimental platforms which reproduce the cardiac phenotype of DMD patients, here we established iPS cell lines from T lymphocytes donated from two DMD patients, with a protocol using Sendai virus vectors. We successfully conducted the differentiation of the DMD patient-specific iPS cells into beating cardiomyocytes. DMD patient-specific iPS cells and iPS cell-derived cardiomyocytes would be a useful in vitro experimental system with which to investigate DMD cardiomyopathy. PMID:26673445

  16. A quantitative analysis of contractility in active cytoskeletal protein networks.

    Science.gov (United States)

    Bendix, Poul M; Koenderink, Gijsje H; Cuvelier, Damien; Dogic, Zvonimir; Koeleman, Bernard N; Brieher, William M; Field, Christine M; Mahadevan, L; Weitz, David A

    2008-04-15

    Cells actively produce contractile forces for a variety of processes including cytokinesis and motility. Contractility is known to rely on myosin II motors which convert chemical energy from ATP hydrolysis into forces on actin filaments. However, the basic physical principles of cell contractility remain poorly understood. We reconstitute contractility in a simplified model system of purified F-actin, muscle myosin II motors, and alpha-actinin cross-linkers. We show that contractility occurs above a threshold motor concentration and within a window of cross-linker concentrations. We also quantify the pore size of the bundled networks and find contractility to occur at a critical distance between the bundles. We propose a simple mechanism of contraction based on myosin filaments pulling neighboring bundles together into an aggregated structure. Observations of this reconstituted system in both bulk and low-dimensional geometries show that the contracting gels pull on and deform their surface with a contractile force of approximately 1 microN, or approximately 100 pN per F-actin bundle. Cytoplasmic extracts contracting in identical environments show a similar behavior and dependence on myosin as the reconstituted system. Our results suggest that cellular contractility can be sensitively regulated by tuning the (local) activity of molecular motors and the cross-linker density and binding affinity. PMID:18192374

  17. Characteristics of deslanoside-induced modulation on jejunal contractility

    Institute of Scientific and Technical Information of China (English)

    Da-Peng Chen; Yong-Jian Xiong; Ze-Yao Tang; Qi-Ying Yao; Dong-Mei Ye; Sha-Sha Liu; Yuan Lin

    2012-01-01

    AIM:TO characterize the dual effects of deslanoside on the contractility of jejunal smooth muscle.METHODS:Eight pairs of different low and high contractile states of isolated jejunal smooth muscle fragment (JSMF) were established.Contractile amplitude of JSMF in different low and high contractile states was selected to determine the effects of deslanoside,and Western blotting analysis was performed to measure the effects of deslanoside on myosin phosphorylation of jejunal smooth muscle.RESULTS:Stimulatory effects on the contractility of JSMF were induced (45.3% ± 4.0% vs 87.0% ± 7.8%,P < 0.01) by deslanoside in 8 low contractile states,and inhibitory effects were induced (180.6% ± 17.8%vs 109.9% ± 10.8%,P < 0.01) on the contractility of JSMF in 8 high contractile states.The effect of deslanoside on the phosphorylation of myosin light chain ofJSMF in low (78.1% ± 4.1% vs 96.0% ± 8.1%,P <0.01) and high contractile state (139.2% ± 8.5% vs 105.5 ± 7.34,P < 0.01) was also bidirectional.Bidirectional regulation (BR) was abolished in the presence of tetrodotoxin.Deslanoside did not affect jejunal contractility pretreated with the Ca2+ channel blocker verapamil or in a Ca2+-free assay condition.The stimulatory effect of deslanoside on JSMF in a low contractile state (low Ca2+ induced) was abolished by atropine.The inhibitory effect of deslanoside on jejunal contractility in a high contractile state (high Ca2+ induced) was blocked by phentolamine,propranolol and L-NG-nitroarginine,respectively.CONCLUSION:Deslanoside-induced BR is Ca2+ dependent and is related to cholinergic and adrenergic systems when JSMF is in low or high contractile states.

  18. Localization of the transmembrane proteoglycan syndecan-4 and its regulatory kinases in costameres of rat cardiomyocytes: a deconvolution microscopic study

    DEFF Research Database (Denmark)

    VanWinkle, W Barry; Snuggs, Mark B; De Hostos, Eugenio L;

    2002-01-01

    Syndecan-4 (syn-4), a transmembrane heparan sulfate-containing proteoglycan, is unique among the four members of the syndecan family in its specific cellular localization to complex cytoskeletal adhesion sites, i.e., focal adhesions. During early phenotypic redifferentiation of neonatal...... cardiomyocytes in culture, immunolocalization reveals syn-4 to be heavily concentrated in the perinuclear endoplasmic reticulum-Golgi region, with little found at the peripheral regions. Subsequently, syn-4 becomes localized to a cytoskeletal adhesion complex unique to striated muscle, the costamere. Soon after....... These findings suggest that syn-4 may not only play a role in cellular adhesion and contractile force transmission, it may also, through ser, thr, and tyr phosphorylation, be part of an interactive signal transduction mechanism in myocardial functioning via these adhesive cytoskeletal complexes....

  19. Genome sequence of Haloplasma contractile, an unusual contractile bacterium from a deep-sea anoxic brine lake.

    KAUST Repository

    Antunes, Andre

    2011-09-01

    We present the draft genome of Haloplasma contractile, isolated from a deep-sea brine and representing a new order between Firmicutes and Mollicutes. Its complex morphology with contractile protrusions might be strongly influenced by the presence of seven MreB/Mbl homologs, which appears to be the highest copy number ever reported.

  20. Considerations for Contractile Electroactive Materials and Actuators

    Energy Technology Data Exchange (ETDEWEB)

    Lenore Rasmussen, David Schramm, Paul Rasmussen, Kevin Mullaly, Ras Labs, LLC, Intelligent Materials for Prosthetics & Automation, Lewis D. Meixler, Daniel Pearlman and Alice Kirk

    2011-05-23

    Ras Labs produces contractile electroactive polymer (EAP) based materials and actuators that bend, swell, ripple, and contract (new development) with low electric input. In addition, Ras Labs produces EAP materials that quickly contract and expand, repeatedly, by reversing the polarity of the electric input, which can be cycled. This phenomenon was explored using molecular modeling, followed by experimentation. Applied voltage step functions were also investigated. High voltage steps followed by low voltage steps produced a larger contraction followed by a smaller contraction. Actuator control by simply adjusting the electric input is extremely useful for biomimetic applications. Muscles are able to partially contract. If muscles could only completely contract, nobody could hold an egg, for example, without breaking it. A combination of high and low voltage step functions could produce gross motor function and fine manipulation within the same actuator unit. Plasma treated electrodes with various geometries were investigated as a means of providing for more durable actuation.

  1. Considerations For Contractile Electroactive Materials and Actuators

    Energy Technology Data Exchange (ETDEWEB)

    Lenore Rasmussen, Lewis D. Meixler and Charles A. Gentile

    2012-02-29

    Electroactive polymers (EAPs) that bend, swell, ripple (first generation materials), and now contract with low electric input (new development) have been produced. The mechanism of contraction is not well understood. Radionuclide-labeled experiments, molecular modeling, electrolyte experiments, pH experiments, and an ionic concentration experiment were used to determine the chain of events that occur during contraction and, reciprocally, expansion when the polarity is reversed, in these ionic EAPs. Plasma treatment of the electrodes, along with other strategies, allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface, analogous to nerves and tendons moving with muscles during movement. Challenges involved with prototyping actuation using contractile EAPs are also discussed.

  2. Isolation and culture of cardiomyocytes in adult rat of heart failure and study of pathophysiological characteristics%心力衰竭大鼠心肌细胞的分离培养和病理生理特性研究

    Institute of Scientific and Technical Information of China (English)

    王彤; 万智; 黄辉; 符岳; 黄子通

    2008-01-01

    Objective To isolate and culture of cardiomyocytes in adult rat of heart failure and observe pathophysiological characteristics of single cardiomyocytes with a IonOptix TM system. Methods Opened chest of 5 rats and ligated the left anterior descending coronary artery (LAD). Four weeks later, finished echocardiographically measured ejection fraction (EF) , the heart was cut and hanged on to the Langendorff apparatus for perfusion and collagenase digestion. The single cardiomyocytes were cultured in serum -free medium with laminin - covered dishes. The morphological features of cardiomyocytes of heart failure rats were observed with microscope. With perfusion and field - stimulation (0.5 Hz ,3 ms) ,the cardiomyocytes contraction were simultaneously recorded by IonOptix TM and compared with the cardiomyocytes of 5 normal rats. Results There were obvious symptoms in heart failure rats. EF was significantly decreased in rats 4 weeks after LAD ligated[ (55 + 3 ) % vs (78 ± 4) %, P = 0. 00002 ]. The total of freshly isolated cardiomyocytes in heart failure rats was significantly lower than normal rats [ (5.6±0.3 )×106vs ( 8. 1±1. 2 ) × 106, P = 0. 0014 ]. Rodshaped cells in heart failure rats became longer significantly than rod - shaped cells in normal rats [ ( 152±19 )μm vs (133±17 )μm, P = 0.03 ]. The amplitude of shortening/relengthening and contractile velocity of these cells in heart failure rats was significantly lessen than these cells in normal rats [ ( 7.5±3.2 )% vs ( 13±3)%, P = 0.0016;(36±18)μm/ms vs (60±19)μm/ms, P =0.009]. Conclusion Compared with cardiomyocytes obtained from normal rats, cardiomyocytes obtained from heart failure rats have obvious pathophysiological characteristics. These data can describe the cell level change of myocardial dysfunction induced by different diseases and drugs treatment.%目的 分离培养心力衰竭(心衰)大鼠心肌细胞,以及利用IonOptix TM系统观察心衰大鼠离体心肌细胞的收缩舒张

  3. Usage of echocardiography with physical loads for diagnosis of myocardial contractile reserve of the left ventricle in athletes

    Directory of Open Access Journals (Sweden)

    Nekhanevich O.B.

    2014-09-01

    Full Text Available The work purpose was studying of myocardial contractile reserve of the left ventricle and cardiohemodynamics infringements character under the influence of physical loads in athletes with functional insufficiency of mitral valve according to stress-echocardiography. We examined 72 athletes the aged 9 to 40 years with functional mitral valve insufficiency and normal systolic function of the heart at rest by echo ECG data. Possibility of stress echocardiography with physical loads usage to diagnose decrease of myocardial contractile reserve of the heart left ventricle was proved. It was found that increase in hemodynamic load during physical exercise leads to the disruption of adaptation and manifestation of systolic dysfunction in athletes with I and II degrees of mitral valve regurgitation. This should be considered when constructing training-competitive loads among athletes in terms of prevention of acute physical overloading.

  4. Hadp1, a newly identified pleckstrin homology domain protein, is required for cardiac contractility in zebrafish

    Directory of Open Access Journals (Sweden)

    Joshua D. Wythe

    2011-09-01

    The vertebrate heart is one of the first organs to form, and its early function and morphogenesis are crucial for continued embryonic development. Here we analyze the effects of loss of Heart adaptor protein 1 (Hadp1, which we show is required for normal function and morphogenesis of the embryonic zebrafish heart. Hadp1 is a pleckstrin homology (PH-domain-containing protein whose expression is enriched in embryonic cardiomyocytes. Knockdown of hadp1 in zebrafish embryos reduced cardiac contractility and altered late myocyte differentiation. By using optical mapping and submaximal levels of hadp1 knockdown, we observed profound effects on Ca2+ handling and on action potential duration in the absence of morphological defects, suggesting that Hadp1 plays a major role in the regulation of intracellular Ca2+ handling in the heart. Hadp1 interacts with phosphatidylinositol 4-phosphate [PI4P; also known as PtdIns(4P] derivatives via its PH domain, and its subcellular localization is dependent upon this motif. Pharmacological blockade of the synthesis of PI4P derivatives in vivo phenocopied the loss of hadp1 in zebrafish. Collectively, these results demonstrate that hadp1 is required for normal cardiac function and morphogenesis during embryogenesis, and suggest that hadp1 modulates Ca2+ handling in the heart through its interaction with phosphatidylinositols.

  5. Mitochondrial translocation of Nur77 induced by ROS contributed to cardiomyocyte apoptosis in metabolic syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Aibin; Liu, Jingyi [Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi’an (China); Institute of Cardiovascular Disease, General Hospital of Beijing Command, PLA, Beijing (China); Liu, Peilin; Jia, Min; Wang, Han [Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi’an (China); Tao, Ling, E-mail: lingtao2006@gmail.com [Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi’an (China)

    2014-04-18

    Highlights: • Metabolic syndrome exacerbated MI/R induced injury accompanied by decreased Nur77. • ROS led to Nur77 translocation in metabolic syndrome. • Inhibiting relocation of Nur77 to mitochondria reduced ROS-induced cardiomyocyte injury in metabolic syndrome. - Abstract: Metabolic syndrome is a major risk factor for cardiovascular diseases, and increased cardiomyocyte apoptosis which contributes to cardiac dysfunction after myocardial ischemia/reperfusion (MI/R) injury. Nur77, a nuclear orphan receptor, is involved in such various cellular events as apoptosis, proliferation, and glucose and lipid metabolism in several cell types. Apoptosis is positively correlated with mitochondrial translocation of Nur77 in the cancer cells. However, the roles of Nur77 on cardiac myocytes in patients with metabolic syndrome remain unclear. The objective of this study was to determine whether Nur77 may contribute to cardiac apoptosis in patients with metabolic syndrome after I/R injury, and, if so, to identify the underlying molecular mechanisms responsible. We used leptin-deficient (ob/ob) mice to make metabolic syndrome models. In this report, we observed that, accompanied by the substantial decline in apoptosis inducer Nur77, MI/R induced cardiac dysfunction was manifested as cardiomyopathy and increased ROS. Using the neonatal rat cardiac myocytes cultured in a high-glucose and high-fat medium, we found that excessive H{sub 2}O{sub 2} led to the significant alteration in mitochondrial membrane potential and translocation of Nur77 from the nucleus to the mitochondria. However, inhibition of the relocation of Nur77 to mitochondria via Cyclosporin A reversed the changes in membrane potential mediated by H{sub 2}O{sub 2} and reduced myocardial cell injury. Therefore, these data provide a potential underlying mechanism for cardiac dysfunction in metabolic syndrome and the suppression of Nur77 translocation may provide an effective approach to reduce cardiac injury in the

  6. Effects of Crocetin Esters and Crocetin from Crocus sativus L. on Aortic Contractility in Rat Genetic Hypertension

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    Silvia Llorens

    2015-09-01

    Full Text Available Background: Endothelial dysfunction, characterized by an enhancement in vasoconstriction, is clearly associated with hypertension. Saffron (Crocus sativus L. bioactive compounds have been recognized to have hypotensive properties. Recently, we have reported that crocetin exhibits potent vasodilator effects on isolated aortic rings from hypertensive rats. In this work, we have aimed to analyze the anticontractile ability of crocetin or crocetin esters pool (crocins isolated from saffron. Thus, we have studied the effects of saffron carotenoids on endothelium-dependent and -independent regulation of smooth muscle contractility in genetic hypertension. Methods: We have measured the isometric responses of aortic segments with or without endothelium obtained from spontaneously hypertensive rats. The effects of carotenoids were studied by assessing the endothelial modulation of phenylephrine-induced contractions (10−9–10−5 M in the presence or absence of crocetin or crocins. The role of nitric oxide and prostanoids was analyzed by performing the experiments with L-NAME (NG-nitro-l-arginine methyl ester or indomethacin (both 10−5 M, respectively. Results: Crocetin, and to a minor extent crocins, diminished the maximum contractility of phenylephrine in intact rings, while crocins, but not crocetin, increased this contractility in de-endothelizated vessels. In the intact vessels, the effect of crocetin on contractility was unaffected by indomethacin but was abolished by L-NAME. However, crocetin but not crocins, lowered the already increased contractility caused by L-NAME. Conclusions: Saffron compounds, but especially crocetin have endothelium-dependent prorelaxing actions. Crocins have procontractile actions that take place via smooth muscle cell mechanisms. These results suggest that crocetin and crocins activate different mechanisms involved in the vasoconstriction pathway in hypertension.

  7. Intracellular diffusion restrictions in isolated cardiomyocytes from rainbow trout

    Directory of Open Access Journals (Sweden)

    Birkedal Rikke

    2009-12-01

    Full Text Available Abstract Background Restriction of intracellular diffusion of adenine nucleotides has been studied intensively on adult rat cardiomyocytes. However, their cause and role in vivo is still uncertain. Intracellular membrane structures have been suggested to play a role. We therefore chose to study cardiomyocytes from rainbow trout (Oncorhynchus mykiss, which are thinner and have fewer intracellular membrane structures than adult rat cardiomyocytes. Previous studies suggest that trout permeabilized cardiac fibers also have diffusion restrictions. However, results from fibers may be affected by incomplete separation of the cells. This is avoided when studying permeabilized, isolated cardiomyocytes. The aim of this study was to verify the existence of diffusion restrictions in trout cardiomyocytes by comparing ADP-kinetics of mitochondrial respiration in permeabilized fibers, permeabilized cardiomyocytes and isolated mitochondria from rainbow trout heart. Experiments were performed at 10, 15 and 20°C in the absence and presence of creatine. Results Trout cardiomyocytes hypercontracted in the solutions used for mammalian cardiomyocytes. We developed a new solution in which they retained their shape and showed stable steady state respiration rates throughout an experiment. The apparent ADP-affinity of permeabilized cardiomyocytes was different from that of fibers. It was higher, independent of temperature and not increased by creatine. However, it was still about ten times lower than in isolated mitochondria. Conclusions The differences between fibers and cardiomyocytes suggest that results from trout heart fibers were affected by incomplete separation of the cells. However, the lower ADP-affinity of cardiomyocytes compared to isolated mitochondria indicate that intracellular diffusion restrictions are still present in trout cardiomyocytes despite their lower density of intracellular membrane structures. The lack of a creatine effect indicates that

  8. From pluripotency to distinct cardiomyocyte subtypes.

    Science.gov (United States)

    David, Robert; Franz, Wolfgang-Michael

    2012-06-01

    Differentiated adult cardiomyocytes (CMs) lack significant regenerative potential, which is one reason why degenerative heart diseases are the leading cause of death in the western world. For future cardiac repair, stem cell-based therapeutic strategies may become alternatives to donor heart transplantation. The principle of reprogramming adult terminally differentiated cells (iPSC) had a major impact on stem cell biology. One can now generate autologous pluripotent cells that highly resemble embryonic stem cells (ESC) and that are ethically inoffensive as opposed to human ESC. Yet, due to genetic and epigenetic aberrations arising during the full reprogramming process, it is questionable whether iPSC will enter the clinic in the near future. Therefore, the recent achievement of directly reprogramming fibroblasts into cardiomyocytes via a milder approach, thereby avoiding an initial pluripotent state, may become of great importance. In addition, various clinical scenarios will depend on the availability of specific cardiac cellular subtypes, for which a first step was achieved via our own programming approach to achieve cardiovascular cell subtypes. In this review, we discuss recent progress in the cardiovascular stem cell field addressing the above mentioned aspects. PMID:22689787

  9. Dysfunctional voiding.

    Science.gov (United States)

    Chiozza, M L

    2002-01-01

    Wetting may be considered the Cinderella of paediatric medicine. Before discussing dysfunctional voiding, the milestones of the normal development of continence in the child and the definitions used to describe this topic are presented. Bladder storage requires (1): accommodation of increasing volumes of urine at low intravesical pressure and with appropriate sensation; (2): a bladder outlet that is closed and not modified during increase in intra-abdominal pressure; (3): absence of involuntary bladder contractions. Development of continence in the child involves three independent factors maturing concomitantly: (1) development of normal bladder capacity; (2) maturation of urethral sphincter function; (3) development of neural control over bladder-sphincter function. All these processes are discussed. Abnormalities of any of these maturational sequences, which run parallel and overlapping, may result in clinically evident abnormalities of bladder sphincter control. Although dysfunctional voiding (DV) in children is very common its prevalence has not been well studied and, to date, and its origin is not well known. In a correct evaluation of functional voiding we must take into account different elements: the bladder capacity (that increases during the first 8 years of life roughly 30 ml per year), the micturition frequency, post-void residual volumes, bladder dynamics, urinary flow rates. Thus the correct assessment of children with lower urinary tract dysfunction should include a detailed history. Signs of DV range from urge syndrome to complex incontinence patterns during the day and the night. In addition to incontinence problems, children may have frequency, urgency, straining to void, weak or interrupted urinary stream, urinary tract infections (UTIs) and chronic constipation with or without encopresis. DV are also referred in enuretic children who wet the bed more than one time per night and have a functional bladder capacity lower than attended for age

  10. Mitochondrial dysfunction in heart failure.

    Science.gov (United States)

    Rosca, Mariana G; Hoppel, Charles L

    2013-09-01

    Heart failure (HF) is a complex chronic clinical syndrome. Energy deficit is considered to be a key contributor to the development of both cardiac and skeletal myopathy. In HF, several components of cardiac and skeletal muscle bioenergetics are altered, such as oxygen availability, substrate oxidation, mitochondrial ATP production, and ATP transfer to the contractile apparatus via the creatine kinase shuttle. This review focuses on alterations in mitochondrial biogenesis and respirasome organization, substrate oxidation coupled with ATP synthesis in the context of their contribution to the chronic energy deficit, and mechanical dysfunction of the cardiac and skeletal muscle in HF. We conclude that HF is associated with decreased mitochondrial biogenesis and function in both heart and skeletal muscle, supporting the concept of a systemic mitochondrial cytopathy. The sites of mitochondrial defects are located within the electron transport and phosphorylation apparatus and differ with the etiology and progression of HF in the two mitochondrial populations (subsarcolemmal and interfibrillar) of cardiac and skeletal muscle. The roles of adrenergic stimulation, the renin-angiotensin system, and cytokines are evaluated as factors responsible for the systemic energy deficit. We propose a cyclic AMP-mediated mechanism by which increased adrenergic stimulation contributes to the mitochondrial dysfunction.

  11. Contractile Changes in the Vasculature After Subchronic Smoking

    DEFF Research Database (Denmark)

    Haanes, Kristian Agmund; Kruse, Lars Schack; Johansson, Helle Wulf;

    2016-01-01

    : Wild type (WT) and SP-D KO mice were exposed to cigarette smoke (CS) or room air for 12 weeks. The pulmonary artery, left anterior descending coronary artery, and basilar artery (BA) were isolated and mounted in wire myographs. Contractile concentration response curves to endothelin-1 and UDP were...... displayed no smoke induced changes, but were surprisingly similar to the CSE WT. CONCLUSION: The contractility to UDP was altered in the brain and heart vasculature of CSE mice. SP-D KO (both control and CSE) and CSE WT had similar changes in contractility compared to control WT. IMPLICATIONS: These results...

  12. Protective Effects of Estradiol on Myocardial Contractile Function Following Hemorrhagic Shock and Resuscitation in Rats

    Institute of Scientific and Technical Information of China (English)

    Mona Soliman

    2015-01-01

    Background:Hemorrhagic shock (HS) results in myocardial contractile dysfunction.Studies showed that 17β-estradiol protects the myocardium against contractile dysfunction.The study investigated the cardioprotective effects of treatment with 17β-estradiol before resuscitation following 1 h of HS and resuscitation.Methods:Male Sprague-Dawley rats were assigned to 2 sets of experimental protocols:Ex vivo and in vivo treatment and resuscitation.Each set had three experimental groups (n =6 per group):Normotensive (N),HS and resuscitation (HS-R) and HS rats treated with 17β-estradiol (E) and resuscitated (HS-E-R).Rats were hemorrhaged over 60-min to reach a mean arterial blood pressure of 40 mmHg.In the ex vivo group,hearts were resuscitated by perfusion in the Langendorff system.In the 17β-estradiol treated group,17β-estradiol 280 μg/kg was added for the first 5 min.Cardiac function was measured.Left ventricular generated pressure (LVGP) and +dP/dt were calculated.In the in vivo group,rats were treated with 17β-estradiol 280 μg/kg s.c.after 60-min HS.Resuscitation was performed in vivo by the reinfusion of the shed blood for 30-min to restore normotension.Results:Treatment with 17β-estradiol before resuscitation in ex vivo treated and resuscitated isolated hearts and in the in vivo treated and resuscitated rats following HS improved myocardial contractile function.In the in vivo treated group,LVGP and +dP/dt max were significantly higher in 17β-estradiol treated rats compared to the untreated group (LVGP 136.40 ± 6.61 compared to 47.58 ± 17.55,and +dP/dt 661.85 ± 49.88 compared to 88.18 ± 0.85).Treatment with 17β-estradiol improved LVGP following HS.Conclusions:The results indicate that treatment with 17β-estradiol before resuscitation following HS protects the myocardium against dysfunction.

  13. Opportunities to Target Specific Contractile Abnormalities with Smooth Muscle Protein Kinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Annegret Ulke-Lemée

    2010-05-01

    Full Text Available Smooth muscle is a major component of most hollow organ systems (e.g., airways, vasculature, bladder and gut/gastrointestine; therefore, the coordinated regulation of contraction is a key property of smooth muscle. When smooth muscle functions normally, it contributes to general health and wellness, but its dysfunction is associated with morbidity and mortality. Rho-associated protein kinase (ROCK is central to calcium-independent, actomyosin-mediated contractile force generation in the vasculature, thereby playing a role in smooth muscle contraction, cell motility and adhesion. Recent evidence supports an important role for ROCK in the increased vasoconstriction and remodeling observed in various models of hypertension. This review will provide a commentary on the development of specific ROCK inhibitors and their clinical application. Fasudil will be discussed as an example of bench-to-bedside development of a clinical therapeutic that is used to treat conditions of vascular hypercontractility. Due to the wide spectrum of biological processes regulated by ROCK, many additional clinical indications might also benefit from ROCK inhibition. Apart from the importance of ROCK in smooth muscle contraction, a variety of other protein kinases are known to play similar roles in regulating contractile force. The zipper-interacting protein kinase (ZIPK and integrin-linked kinase (ILK are two well-described regulators of contraction. The relative contribution of each kinase to contraction depends on the muscle bed as well as hormonal and neuronal stimulation. Unfortunately, specific inhibitors for ZIPK and ILK are still in the development phase, but the success of fasudil suggests that inhibitors for these other kinases may also have valuable clinical applications. Notably, the directed inhibition of ZIPK with a pseudosubstrate molecule shows unexpected effects on the contractility of gastrointestinal smooth muscle.

  14. Myocardial mitochondrial and contractile function are preserved in mice lacking adiponectin.

    Directory of Open Access Journals (Sweden)

    Martin Braun

    Full Text Available Adiponectin deficiency leads to increased myocardial infarct size following ischemia reperfusion and to exaggerated cardiac hypertrophy following pressure overload, entities that are causally linked to mitochondrial dysfunction. In skeletal muscle, lack of adiponectin results in impaired mitochondrial function. Thus, it was our objective to investigate whether adiponectin deficiency impairs mitochondrial energetics in the heart. At 8 weeks of age, heart weight-to-body weight ratios were not different between adiponectin knockout (ADQ-/- mice and wildtypes (WT. In isolated working hearts, cardiac output, aortic developed pressure and cardiac power were preserved in ADQ-/- mice. Rates of fatty acid oxidation, glucose oxidation and glycolysis were unchanged between groups. While myocardial oxygen consumption was slightly reduced (-24% in ADQ-/- mice in isolated working hearts, rates of maximal ADP-stimulated mitochondrial oxygen consumption and ATP synthesis in saponin-permeabilized cardiac fibers were preserved in ADQ-/- mice with glutamate, pyruvate or palmitoyl-carnitine as a substrate. In addition, enzymatic activity of respiratory complexes I and II was unchanged between groups. Phosphorylation of AMP-activated protein kinase and SIRT1 activity were not decreased, expression and acetylation of PGC-1α were unchanged, and mitochondrial content of OXPHOS subunits was not decreased in ADQ-/- mice. Finally, increasing energy demands due to prolonged subcutaneous infusion of isoproterenol did not differentially affect cardiac contractility or mitochondrial function in ADQ-/- mice compared to WT. Thus, mitochondrial and contractile function are preserved in hearts of mice lacking adiponectin, suggesting that adiponectin may be expendable in the regulation of mitochondrial energetics and contractile function in the heart under non-pathological conditions.

  15. Ascorbic acid delivered by mesoporous silica nanoparticles induces the differentiation of human embryonic stem cells into cardiomyocytes.

    Science.gov (United States)

    Ren, Mingming; Han, Zhen; Li, Jinglai; Feng, Gang; Ouyang, Shuyuan

    2015-11-01

    Embryonic stem (ES) cells offer the potential to generate all cell types in the body, which provide a promising approach to repair tissue damage or dysfunction. In the past decade, great efforts have been made to induce the differentiation of ES cells into numerous types of cells, such as adipocytes, neurocytes and cardiomyocytes. However, the low differentiated efficiency and successful rate limit the development of induction of the differentiation of stem cells for tissue engineering. Here, we utilize ascorbic acid (AA)-loaded fluorescent TRITC-mesoporous silica nanoparticles (TMSN-AA) as a potential tool to induce the differentiation of human ES cells into cardiomyocytes. The treatment of human ES cells by TMSN-AA nanoplex arrests cell cycle at G1 phase and decreases the expression of stemness genes octamer-binding transcription factor 4 (OCT4) and sex determining region Y-box 2 (SOX2), which exhibits more significant induction efficiency of stem cell differentiation than the treatment by AA alone. Furthermore, we have tested the myocardial marker genes cardiac Troponin I (cTnI) and fetal liver kinase 1 (FLK-1), and found these genes are up-regulated by TMSN-AA nanoplex. Importantly, this work demonstrates the more efficient induction efficiency of human ES cells differentiation by the nanoparticle-drug formulation. Our studies reveal a novel approach based on MSNs as nanocarriers to induce the differentiation of human ES cells into cardiomyocytes efficiently and feasibly, and offer the potential perspectives for tissue engineering, eventually in clinical applications.

  16. Geometrical Origins of Contractility in Disordered Actomyosin Networks

    Science.gov (United States)

    Lenz, Martin

    2014-10-01

    Movement within eukaryotic cells largely originates from localized forces exerted by myosin motors on scaffolds of actin filaments. Although individual motors locally exert both contractile and extensile forces, large actomyosin structures at the cellular scale are overwhelmingly contractile, suggesting that the scaffold serves to favor contraction over extension. While this mechanism is well understood in highly organized striated muscle, its origin in disordered networks such as the cell cortex is unknown. Here, we develop a mathematical model of the actin scaffold's local two- or three-dimensional mechanics and identify four competing contraction mechanisms. We predict that one mechanism dominates, whereby local deformations of the actin break the balance between contraction and extension. In this mechanism, contractile forces result mostly from motors plucking the filaments transversely rather than buckling them longitudinally. These findings shed light on recent in vitro experiments and provide a new geometrical understanding of contractility in the myriad of disordered actomyosin systems found in vivo.

  17. Genetic fuzzy system predicting contractile reactivity patterns of small arteries

    DEFF Research Database (Denmark)

    Tang, J; Sheykhzade, Majid; Clausen, B F;

    2014-01-01

    strategies. Results show that optimized fuzzy systems (OFSs) predict contractile reactivity of arteries accurately. In addition, OFSs identified significant differences that were undetectable using conventional analysis in the responses of arteries between groups. We concluded that OFSs may be used...

  18. Assessment of developmental cardiotoxic effects of some commonly used phytochemicals in mouse embryonic D3 stem cell differentiation and chick embryonic cardiomyocyte micromass culture models.

    Science.gov (United States)

    Mohammed, Omar J; McAlpine, Roseanna; Chiewhatpong, Phasawee; Latif, Muhammad Liaque; Pratten, Margaret K

    2016-09-01

    Pregnant women often use herbal medicines to alleviate symptoms of pregnancy. The active phytochemicals eugenol (from holy basil) and α-bisabolol (from chamomile) are recommended to promote calmness and reduce stress. There is evidence that both eugenol and α-bisabolol possess pro-apoptotic and anti-proliferative effects and induce reactive oxygen species. The potential effect was examined by monitoring cardiomyocyte contractile activity (differentiation), cell activity, protein content and ROS production for mouse D3 embryonic stem cell and ‎chick embryonic micromass culture. The results showed that eugenol (0.01-80μM) demonstrated effects on cell activity (both systems) and ROS production (stem cell system only), as well as decreasing the contractile activity and protein content at high concentrations in both systems. Additionally, α-bisabolol (0.01-80μM) at high concentrations decreased the contractile activity and cell activity and in the stem cell system induced ROS production and decreased protein content. The results suggest only low concentrations should be ingested in pregnancy.‎. PMID:27105832

  19. Considerations for Contractile Electroactive Materials and Actuators

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Lenore; Erickson, Carl J.; Meixler, Lewis D.; Ascione, George; Gentile, Charles A.; Tilson, Carl; Bernasek, Stephen L.; Abelev, Esta

    2010-02-19

    Ras Labs produces electroactive polymer (EAP) based materials and actuators that bend, swell, ripple and now contract (new development) with low electric input. This is an important attribute because of the ability of contraction to produce life-like motion. The mechanism of contraction is not well understood. Radionuclide-labeled experiments were conducted to follow the movement of electrolytes and water in these EAPs when activated. Extreme temperature experiments were performed on the contractile EAPs with very favorable results. One of the biggest challenges in developing these actuators, however, is the electrode-EAP interface because of the pronounced movement of the EAP. Plasma treatments of metallic electrodes were investigated in order to improve the attachment of the embedded electrodes to the EAP material. Surface analysis, adhesive testing, and mechanical testing were conducted to test metal surfaces and metal-polymer interfaces. The nitrogen plasma treatment of titanium produced a strong metal-polymer interface; however, oxygen plasma treatment of both stainless steel and titanium produced even stronger metal-polymer interfaces. Plasma treatment of the electrodes allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface.

  20. Epigenetic Reprogramming of Human Embryonic Stem Cells into Skeletal Muscle Cells and Generation of Contractile Myospheres

    Directory of Open Access Journals (Sweden)

    Sonia Albini

    2013-03-01

    Full Text Available Direct generation of a homogeneous population of skeletal myoblasts from human embryonic stem cells (hESCs and formation of three-dimensional contractile structures for disease modeling in vitro are current challenges in regenerative medicine. Previous studies reported on the generation of myoblasts from ESC-derived embryoid bodies (EB, but not from undifferentiated ESCs, indicating the requirement for mesodermal transition to promote skeletal myogenesis. Here, we show that selective absence of the SWI/SNF component BAF60C (encoded by SMARCD3 confers on hESCs resistance to MyoD-mediated activation of skeletal myogenesis. Forced expression of BAF60C enables MyoD to directly activate skeletal myogenesis in hESCs by instructing MyoD positioning and allowing chromatin remodeling at target genes. BAF60C/MyoD-expressing hESCs are epigenetically committed myogenic progenitors, which bypass the mesodermal requirement and, when cultured as floating clusters, give rise to contractile three-dimensional myospheres composed of skeletal myotubes. These results identify BAF60C as a key epigenetic determinant of hESC commitment to the myogenic lineage and establish the molecular basis for the generation of hESC-derived myospheres exploitable for “disease in a dish” models of muscular physiology and dysfunction.

  1. Epigenetic reprogramming of human embryonic stem cells into skeletal muscle cells and generation of contractile myospheres.

    Science.gov (United States)

    Albini, Sonia; Coutinho, Paula; Malecova, Barbora; Giordani, Lorenzo; Savchenko, Alex; Forcales, Sonia Vanina; Puri, Pier Lorenzo

    2013-03-28

    Direct generation of a homogeneous population of skeletal myoblasts from human embryonic stem cells (hESCs) and formation of three-dimensional contractile structures for disease modeling in vitro are current challenges in regenerative medicine. Previous studies reported on the generation of myoblasts from ESC-derived embryoid bodies (EB), but not from undifferentiated ESCs, indicating the requirement for mesodermal transition to promote skeletal myogenesis. Here, we show that selective absence of the SWI/SNF component BAF60C (encoded by SMARCD3) confers on hESCs resistance to MyoD-mediated activation of skeletal myogenesis. Forced expression of BAF60C enables MyoD to directly activate skeletal myogenesis in hESCs by instructing MyoD positioning and allowing chromatin remodeling at target genes. BAF60C/MyoD-expressing hESCs are epigenetically committed myogenic progenitors, which bypass the mesodermal requirement and, when cultured as floating clusters, give rise to contractile three-dimensional myospheres composed of skeletal myotubes. These results identify BAF60C as a key epigenetic determinant of hESC commitment to the myogenic lineage and establish the molecular basis for the generation of hESC-derived myospheres exploitable for "disease in a dish" models of muscular physiology and dysfunction.

  2. Influence of the cardiac myosin hinge region on contractile activity.

    OpenAIRE

    Margossian, S S; Krueger, J W; Sellers, J R; Cuda, G; Caulfield, J B; Norton, P.; Slayter, H. S.

    1991-01-01

    The participation of cardiac myosin hinge in contractility was investigated by in vitro motility and ATPase assays and by measurements of sarcomere shortening. The effect on contractile activity was analyzed using an antibody directed against a 20-amino acid peptide within the hinge region of myosin. This antibody bound specifically at the hinge at a distance of 55 nm from the S1/S2 junction, was specific to human, dog, and rat cardiac myosins, did not crossreact with gizzard or skeletal myos...

  3. Modelling maternal obesity: the effects of a chronic high-fat, high-cholesterol diet on uterine expression of contractile-associated proteins and ex vivo contractile activity during labour in the rat.

    Science.gov (United States)

    Muir, Ronan; Ballan, Jean; Clifford, Bethan; McMullen, Sarah; Khan, Raheela; Shmygol, Anatoly; Quenby, Siobhan; Elmes, Matthew

    2016-02-01

    Maternal obesity is associated with prolonged and dysfunctional labour and emergency caesarean section, but the mechanisms are unknown. The present study investigated the effects of an adiposity-inducing high-fat, high-cholesterol (HFHC) diet on uterine contractile-associated protein (CAP) expression and ex vivo uterine contractility in term non-labouring (TNL) and term labouring (TL) rats. Female rats were fed either control chow (CON n=20) or HFHC (n=20) diet 6 weeks before conception and during pregnancy. On gestational day 21 (TNL) or day 22 (TL) CON and HFHC (n=10) rats were killed to determine plasma cholesterol, triacylglycerol and progesterone concentrations and collection of myometrium for contractility studies and expression of CAPs caveolin-1 (Cav-1), connexin-43 (CX-43) and it's phosphorylated form (pCX-43), oxytocin receptor (OXTR) and cyclooxygenase-2 (COX-2). HFHC feeding increased visceral fat (P≤0.001), plasma cholesterol (P≤0.001) and triacylglycerol (P=0.039) concentrations. Stage of labour effected uterine expression of CAV-1 (Pobesity. Uterine dose response to oxytocin was blunted during labour in HFHC rats with a log EC50 of -8.84 compared with -10.25 M in CON for integral activity (Pobese women.

  4. Enhancing lysosome biogenesis attenuates BNIP3-induced cardiomyocyte death

    OpenAIRE

    Ma, Xiucui; Godar, Rebecca J.; Liu, Haiyan; Diwan, Abhinav

    2012-01-01

    Hypoxia-inducible pro-death protein BNIP3 (BCL-2/adenovirus E1B 19-kDa interacting protein 3), provokes mitochondrial permeabilization causing cardiomyocyte death in ischemia-reperfusion injury. Inhibition of autophagy accelerates BNIP3-induced cell death, by preventing removal of damaged mitochondria. We tested the hypothesis that stimulating autophagy will attenuate BNIP3-induced cardiomyocyte death. Neonatal rat cardiac myocytes (NRCMs) were adenovirally transduced with BNIP3 (or LacZ as c...

  5. Telomere-independent cellular senescence in human fetal cardiomyocytes

    OpenAIRE

    Ball, Andrew J.; Levine, F

    2005-01-01

    Fetal cardiomyocytes have been proposed as a potential source of cell-based therapy for heart failure. This study examined cellular senescence in cultured human fetal ventricular cardiomyocytes (HFCs). HFCs were isolated and identified by immunocytochemistry and RT-PCR. Cells were found to senesce after 20-25 population doublings, as determined by growth arrest, morphological changes and senescence-associated beta-galactosidase activity. Using the telomeric repeat amplification protocol assay...

  6. Extracellular Recordings of Field Potentials from Single Cardiomyocytes

    OpenAIRE

    Klauke, Norbert; Smith, Godfrey L.; Cooper, Jon

    2006-01-01

    Open microfluidic channels were used to separate the extracellular space around a cardiomyocyte into three compartments: the cell ends and a central partition (insulating gap). The microchannels were filled with buffer solution and overlaid with paraffin oil, thus forming the cavities for the cell ends. The central part of the cardiomyocyte rested on the partition between two adjacent microchannels and was entirely surrounded by the paraffin oil. This arrangement increased the extracellular e...

  7. Myocardial contractile function and intradialytic hypotension.

    Science.gov (United States)

    Owen, Paul J; Priestman, William S; Sigrist, Mhairi K; Lambie, Stewart H; John, Stephen G; Chesterton, Lindsay J; McIntyre, Christopher W

    2009-07-01

    Dialysis-induced hypotension remains a significant problem in hemodialysis (HD) patients. Numerous factors result in dysregulation of blood pressure control and impaired myocardial reserve in response to HD-induced cardiovascular stress. Episodic intradialytic hypotension may be involved in the pathogenesis of evolving myocardial injury. We performed an initial pilot investigation of cardiovascular functional response to pharmacological cardiovascular stress in hypotension-resistant (HR) and hypotension-prone (HP) HD patients. We studied 10 matched chronic HD patients (5 HP, 5 HR). Dobutamine-atropine stress (DAS) was performed on a nondialysis short interval day, with noninvasive pulse-wave analysis using the Finometer to continuously measure hemodynamic variables. Baroreflex sensitivity was assessed at rest and during DAS. Baseline hemodynamic variables were not significantly different. The groups had differing hemodynamic responses to DAS. The Mean arterial pressure was unchanged in the HR group but decreased in HP patients (-13.6 +/- 3.5 mmHg; P<0.001). This was associated with failure to significantly increase cardiac output in the HP group (cf. increase in cardiac output in the HR group of +33.4 +/- 6%; P<0.05), and a reduced response in total peripheral resistance (HP -10.3 +/- 6.8%, HR -22.7 +/- 2.9%, P=NS). Baroreflex sensitivity was not significantly different between groups at baseline or within groups with increasing levels of DAS; however, the mean baroreflex sensitivity was higher in HR cf. HP subjects throughout pharmacological stress (P<0.05). Hypotension-prone patients appear to have an impaired cardiovascular response to DAS. The most significant abnormality is an impaired myocardial contractile reserve. Early identification of these patients would allow utilization of therapeutic strategies to improve intradialytic tolerability, potentially abrogating aggravation of myocardial injury.

  8. Reconciling depressed Ca2+ sparks occurrence with enhanced RyR2 activity in failing mice cardiomyocytes.

    Science.gov (United States)

    Ruiz-Hurtado, Gema; Li, Linwei; Fernández-Velasco, María; Rueda, Angélica; Lefebvre, Florence; Wang, Yueyi; Mateo, Philippe; Cassan, Cécile; Gellen, Barnabas; Benitah, Jean Pierre; Gómez, Ana María

    2015-10-01

    Abnormalities in cardiomyocyte Ca2+ handling contribute to impaired contractile function in heart failure (HF). Experiments on single ryanodine receptors (RyRs) incorporated into lipid bilayers have indicated that RyRs from failing hearts are more active than those from healthy hearts. Here, we analyzed spontaneous Ca2+ sparks (brief, localized increased in [Ca2+]i) to evaluate RyR cluster activity in situ in a mouse post-myocardial infarction (PMI) model of HF. The cardiac ejection fraction of PMI mice was reduced to ∼30% of that of sham-operated (sham) mice, and their cardiomyocytes were hypertrophied. The [Ca2+]i transient amplitude and sarcoplasmic reticulum (SR) Ca2+ load were decreased in intact PMI cardiomyocytes compared with those from sham mice, and spontaneous Ca2+ sparks were less frequent, whereas the fractional release and the frequency of Ca2+ waves were both increased, suggesting higher RyR activity. In permeabilized cardiomyocytes, in which the internal solution can be controlled, Ca2+ sparks were more frequent in PMI cells (under conditions of similar SR Ca2+ load), confirming the enhanced RyR activity. However, in intact cells from PMI mice, the Ca2+ sparks frequency normalized by the SR Ca2+ load in that cell were reduced compared with those in sham mice, indicating that the cytosolic environment in intact cells contributes to the decrease in Ca2+ spark frequency. Indeed, using an internal "failing solution" with less ATP (as found in HF), we observed a dramatic decrease in Ca2+ spark frequency in permeabilized PMI and sham myocytes. In conclusion, our data show that, even if isolated RyR channels show more activity in HF, concomitant alterations in intracellular media composition and SR Ca2+ load may mask these effects at the Ca2+ spark level in intact cells. Nonetheless, in this scenario, the probability of arrhythmogenic Ca2+ waves is enhanced, and they play a potential role in the increase in arrhythmia events in HF patients. PMID:26371209

  9. Are interstitial cells of Cajal involved in mechanical stress-induced gene expression and impairment of smooth muscle contractility in bowel obstruction?

    Directory of Open Access Journals (Sweden)

    Chester C Wu

    Full Text Available BACKGROUND AND AIMS: The network of interstitial cells of Cajal (ICC is altered in obstructive bowel disorders (OBD. However, whether alteration in ICC network is a cause or consequence of OBD remains unknown. This study tested the hypothesis that mechanical dilation in obstruction disrupts the ICC network and that ICC do not mediate mechanotranscription of COX-2 and impairment of smooth muscle contractility in obstruction. METHODS: Medical-grade silicon bands were wrapped around the distal colon to induce partial obstruction in wild-type and ICC deficient (W/W(v mice. RESULTS: In wild-type mice, colon obstruction led to time-dependent alterations of the ICC network in the proximal colon segment. Although unaffected on days 1 and 3, the ICC density decreased markedly and the network was disrupted on day 7 of obstruction. COX-2 expression increased, and circular muscle contractility decreased significantly in the segment proximal to obstruction. In W/W(v control mice, COX-2 mRNA level was 4.0 (±1.1-fold higher (n=4 and circular muscle contractility was lower than in wild-type control mice. Obstruction further increased COX-2 mRNA level in W/W(v mice to 7.2 (±1.0-fold vs. W/W(v controls [28.8 (±4.1-fold vs. wild-type controls] on day 3. Obstruction further suppressed smooth muscle contractility in W/W(v mice. However, daily administration of COX-2 inhibitor NS-398 significantly improved muscle contractility in both W/W(v sham and obstruction mice. CONCLUSIONS: Lumen dilation disrupts the ICC network. ICC deficiency has limited effect on stretch-induced expression of COX-2 and suppression of smooth muscle contractility in obstruction. Rather, stretch-induced COX-2 plays a critical role in motility dysfunction in partial colon obstruction.

  10. Selective management of cardiovascular dysfunction in posttraumatic SIRS and sepsis.

    Science.gov (United States)

    Martin, R Shayn; Kincaid, Edward H; Russell, Hyde M; Meredith, J Wayne; Chang, Michael C

    2005-03-01

    Cardiovascular dysfunction associated with the systemic inflammatory response syndrome (SIRS) is caused by a combination of decreased myocardial contractility and low vascular resistance. The contribution of each of these components can be determined at the bedside, and directed therapy can be appropriately initiated. Over an 8-month period of time, 23 consecutive patients who experienced posttraumatic SIRS while still being monitored with a volumetric pulmonary artery catheter (PAC) were prospectively evaluated. Ventricular pressure-volume diagrams were constructed to quantify myocardial contractility and afterload. In a resuscitation protocol, dobutamine was administered to patients with an isolated decrease in contractility, and dopamine or epinephrine was instituted for the combination of reduced contractility and afterload. Variables describing cardiovascular function were measured at the time of resolution of initial shock resuscitation (BASE), at the onset of SIRS (ONSET), and after administration of inotropic or vasoactive agents (TREAT). ONSET was associated with a significant decrease in left ventricular power (LVP) (362 +/- 96 to 235 +/- 55 mmHg.L/min/m(2), P index (SWI) (4670 +/- 1213 to 3060 +/- 848 mmHg.mL/m, P SWI significantly increased (235 +/- 55 to 328 +/- 77 mmHg.L/min/m(2), P < 0.00001, and 3060 +/- 848 to 4554 +/- 1423 mmHg.mL/m(2), P < 0.00001, respectively) on the initiation of directed therapy. Specific cardiovascular abnormalities can be identified at the bedside, and this information can guide pharmacologic management. Directed therapy improves cardiovascular function. PMID:15718916

  11. Mechanisms of impaired gallbladder contractile response in chronic acalculous cholecystitis.

    Science.gov (United States)

    Merg, Anders R; Kalinowski, Scott E; Hinkhouse, Marilyn M; Mitros, Frank A; Ephgrave, Kimberly S; Cullen, Joseph J

    2002-01-01

    The mechanisms involved in the impaired gallbladder contractile response in chronic acalculous cholecystitis are unknown. To determine the mechanisms that may lead to impaired gallbladder emptying in chronic acalculous cholecystitis, gallbladder specimens removed during hepatic resection (controls) and after cholecystectomy for chronic acalculous cholecystitis were attached to force transducers and placed in tissue baths with oxygenated Krebs solution. Electrical field stimulation (EFS) (1 to 10 Hz, 0.1 msec, 70 V) or the contractile agonists, CCK-8 (10(-9) to 10(-5)) or K(+) (80 mmol/L), were placed separately in the tissue baths and changes in tension were determined. Patients with chronic acalculous cholecystitis had a mean gallbladder ejection fraction of 12% +/- 4%. Pathologic examination of all gallbladders removed for chronic acalculous cholecystitis revealed chronic cholecystitis. Spontaneous contractile activity was present in gallbladder strips in 83% of control specimens but only 29% of gallbladder strips from patients with chronic acalculous cholecystitis (P < 0.05 vs. controls). CCK-8 contractions were decreased by 54% and EFS-stimulated contractions were decreased by 50% in the presence of chronic acalculous cholecystitis (P < 0.05 vs. controls). K(+)-induced contractions were similar between control and chronic acalculous cholecystitis gallbladder strips. The impaired gallbladder emptying in chronic acalculous cholecystitis appears to be due to diminished spontaneous contractile activity and decreased contractile responsiveness to both CCK and EFS.

  12. Changes of smooth muscle contractile filaments in small bowel atresia

    Institute of Scientific and Technical Information of China (English)

    Stefan Gfroerer; Henning Fiegel; Priya Ramachandran; Udo Rolle; Roman Metzger

    2012-01-01

    AIM:To investigate morphological changes of intestinal smooth muscle contractile fibres in small bowel atresia patients.METHODS:Resected small bowel specimens from small bowel atresia patients (n =12) were divided into three sections (proximal,atretic and distal).Standard histology hematoxylin-eosin staining and enzyme immunohistochemistry was performed to visualize smooth muscle contractile markers α-smooth muscle actin (SMA) and desmin using conventional paraffin sections of the proximal and distal bowel.Small bowel from agematched patients (n =2) undergoing Meckel's diverticulum resection served as controls.RESULTS:The smooth muscle coat in the proximal bowel of small bowel atresia patients was thickened compared with control tissue,but the distal bowel was unchanged.Expression of smooth muscle contractile fibres SMA and desmin within the proximal bowel was slightly reduced compared with the distal bowel and control tissue.There were no major differences in the architecture of the smooth muscle within the proximal bowel and the distal bowel.The proximal and distal bowel in small bowel atresia patients revealed only minimal differences regarding smooth muscle morphology and the presence of smooth muscle contractile filament markers.CONCLUSION:Changes in smooth muscle contractile filaments do not appear to play a major role in postoperative motility disorders in small bowel atresia.

  13. Superoxide dismutase attenuated post-ischaemic contractile dysfunction in a myocardial xanthine oxidase deficient species.

    Science.gov (United States)

    Ooiwa, H; Miura, T; Iwamoto, T; Ogawa, T; Ishimoto, R; Adachi, T; Iimura, O

    1992-02-01

    1. We assessed the effect of polyethylene glycol conjugated superoxide dismutase (PEG-SOD) on myocardial stunning in the rabbit heart in which xanthine oxidase level is extremely low. 2. In open-chest anaesthetized rabbits, the left marginal branch of the coronary artery was occluded for 10 min and then reperfused for 30 min. A group of rabbits (PEG-SOD group) received 1000 units/kg of PED-SOD and another group (control group) was given saline 15 min before the coronary occlusion. 3. Regional systolic thickening fraction (TF) was similarly reduced to approximately -25% of baseline value during ischaemia in both groups. However recovery of TF after reperfusion was significantly better in the PEG-SOD group (n = 9) and TF at 30 min after reperfusion was 70.1 +/- 3.9% of baseline value compared with 44.9 +/- 3.4% in the control group (n = 9; P less than 0.05). Rate-pressure products, left ventricular pressure, and LV dP/dt max were not significantly different between the PEG-SOD treated and untreated control rabbits at any time during the experiment. PEG-SOD did not modify the regional myocardial blood flow (coloured microsphere method) during ischaemia/reperfusion, which was assessed by using separate groups of rabbits. 4. These findings indicate that oxygen free radicals are important in the pathogenesis of myocardial stunning in xanthine oxidase deficient hearts. PMID:1555325

  14. Contractile systolic and diastolic dysfunction in renin-induced hypertensive cardiomyopathy

    NARCIS (Netherlands)

    Flesch, M; Schiffer, F; Zolk, O; Pinto, Y; Rosenkranz, S; HirthDietrich, C; Arnold, G; Paul, M; Bohm, M

    1997-01-01

    The present study investigated whether functional, molecular, and biochemical alterations occurring in chronic heart failure can already be detected in compensated hypertensive cardiac hypertrophy. Force of contraction (isolated papillary muscle strip preparations), sarcoplasmic reticulum (SR) prote

  15. Susceptibility of Diabetic Heart to Catecholamine-induced Arrhythmias is Independent of Contractile Dysfunction

    Directory of Open Access Journals (Sweden)

    Adameova Adriana

    2014-06-01

    Full Text Available Uvod: Dijabetes je udružen sa električnom nestabilnošću miokarda i produženim trajanjem akcionog potencijala što rezultuje poremećajima srčanog ritma. Cilj: Ova studija je sprovedena sa ciljem da ispita ulogu cirkulišućih kateholamina kod poremećaja srčanog ritma i kontraktilnosti miokarda tokom različitih stadijuma dijabetesa. Metode: Kod muških pacova soja Sprague - Dawley dijabetes je izazvan streptozocinom (STZ; 65 mg/kg, i.v.. Aritmije izazvane adrenalinom (4 - 128 μg/kg, i.v. i koncentracija adrenalina i noradrenalina detektovane su u kontrolnoj grupi i nakon 4. i 8. nedelje kod životinja kojima je indukovan dijabetes. Remodelovanje srca kao i kontraktilna funkcija su procenjene ehokardiografi jom. Rezultati: Iako je dijabetes izazvao poremećaj srčane funkcije, nije bilo značajnijih razlika u udarnom volumenu, ejekcionoj frakciji, dimenzijama leve komore, frakcionom skraćenju leve komore između životinja koje imaju dijabetes 4 i 8 nedelja. Elektrokardiogram obe grupe životinja sa dijabetesom pokazao je duboki S talas i promene u T talasu i ST segmentu. Pored toga, došlo je do produženja RR intervala kod životinja koje imaju dijabetes 4 i 8 nedelja, dok se produženje QT i PR intervala javilo samo kod životinja koje imaju dijabetes 8 nedelja. Opasnost od ventikularnih aritmija izazvanih adrenalinom, koja se procenjuje pomoću aritmija skora, bila je značajno niža kod životinja koje imaju dijabetes 8 nedelja u poređenju sa životinjama koje imaju dijabetes 4 nedelje. Nivoi cirkulišućeg adrenalina su bili značajno niži kod životinja koje imaju dijabetes 8 nedelja, dok su nivoi noradrenalina bili povišeni kod životinja koje imaju dijabetes 4 nedelje. Zaključak: Osetljivost dijabetičnog srca na aritmije izazvane kateholaminima može zavisiti više od koncentracije cirkulišuceg adrenalina nego od koncentracije noradrenalina, zbog čega se može pretpostaviti da povećana incidenca iznenadnih srčanih smrti u dijabetesu ne mora biti povezana sa odgovorom na kateholamine.

  16. Sphingomyelinase promotes oxidant production and skeletal muscle contractile dysfunction through activation of NADPH oxidase

    Directory of Open Access Journals (Sweden)

    James A. Loehr

    2015-01-01

    Full Text Available Elevated concentrations of sphingomyelinase (SMase have been detected in a variety of diseases. SMase has been shown to increase muscle derived oxidants and decrease skeletal muscle force; however, the sub-cellular site of oxidant production has not been elucidated. Using redox sensitive biosensors targeted to the mitochondria and NADPH oxidase (Nox2, we demonstrate that SMase increased Nox2-dependent ROS and had no effect on mitochondrial ROS. Pharmacological inhibition and genetic knockdown of Nox2 activity prevented SMase induced ROS production and provided protection against decreased force production. In contrast, genetic overexpression of superoxide dismutase within the mitochondria did not prevent increased ROS production and offered no protection against decreased muscle function in response to SMase. Our study shows that SMase induced ROS production occurs in specific sub-cellular regions of skeletal muscle; however, the increased ROS does not completely account for the decrease in muscle function.

  17. Geometrical origins of contractility in disordered actomyosin networks

    CERN Document Server

    Lenz, Martin

    2014-01-01

    Movement within eukaryotic cells largely originates from localized forces exerted by myosin motors on scaffolds of actin filaments. Although individual motors locally exert both contractile and extensile forces, large actomyosin structures at the cellular scale are overwhelmingly contractile, suggesting that the scaffold serves to favor contraction over extension. While this mechanism is well understood in highly organized striated muscle, its origin in disordered networks such as the cell cortex is unknown. Here we develop a mathematical model of the actin scaffold's local two- or three-dimensional mechanics and identify four competing contraction mechanisms. We predict that one mechanism dominates, whereby local deformations of the actin break the balance between contraction and extension. In this mechanism, contractile forces result mostly from motors plucking the filaments transversely rather than buckling them longitudinally. These findings sheds light on recent $\\textit{in vitro}$ experiments, and provi...

  18. Crocin, a carotenoid component of Crocus cativus, exerts inhibitory effects on L-type Ca(2+) current, Ca(2+) transient, and contractility in rat ventricular myocytes.

    Science.gov (United States)

    Liu, Tao; Chu, Xi; Wang, Hua; Zhang, Xuan; Zhang, Yuanyuan; Guo, Hui; Liu, Zhenyi; Dong, Yongsheng; Liu, Hongying; Liu, Yang; Chu, Li; Zhang, Jianping

    2016-03-01

    Crocin, a carotenoid component of Crocus sativus L. belonging to the Iridaceae family, has demonstrated cardioprotective effects. To investigate the cellular mechanisms of these cardioprotective effects, here we studied the influence of crocin on L-type Ca(2+)current (I(Ca-L)), intracellular Ca(2+) ([Ca(2+)]i), and contraction of isolated rat cardiomyocytes by using the whole-cell patch-clamp technique and video-based edge detection and dual excitation fluorescence photomultiplier systems. Crocin inhibited I(Ca-L) in a concentration-dependent manner with the half-maximal inhibitory concentration (IC50) of 45 μmol/L and the maximal inhibitory effect of 72.195% ± 1.54%. Neither current-voltage relationship of I(Ca-L), reversal potential of I(Ca-L), nor the activation/inactivation of I(Ca-L) was significantly changed. Crocin at 1 μmol/L reduced cell shortening by 44.64% ± 2.12% and the peak value of the Ca(2+) transient by 23.66% ± 4.52%. Crocin significantly reduced amplitudes of myocyte shortening and [Ca(2+)]i with an increase in the time to reach 10% of the peak (Tp) and a decrease in the time to 10% of the baseline (Tr). Thus, the cardioprotective effects of crocin may be attributed to the attenuation of [Ca(2+)]i through the inhibition of I(Ca-L) in rat cardiomyocytes and negative inotropic effects on myocardial contractility.

  19. Glucocorticoid Induced Leucine Zipper inhibits apoptosis of cardiomyocytes by doxorubicin

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, David; Strom, Joshua; Chen, Qin M., E-mail: qchen@email.arizona.edu

    2014-04-01

    Doxorubicin (Dox) is an indispensable chemotherapeutic agent for the treatment of various forms of neoplasia such as lung, breast, ovarian, and bladder cancers. Cardiotoxicity is a major concern for patients receiving Dox therapy. Previous work from our laboratory indicated that glucocorticoids (GCs) alleviate Dox-induced apoptosis in cardiomyocytes. Here we have found Glucocorticoid-Induced Leucine Zipper (GILZ) to be a mediator of GC-induced cytoprotection. GILZ was found to be induced in cardiomyocytes by GC treatment. Knocking down of GILZ using siRNA resulted in cancelation of GC-induced cytoprotection against apoptosis by Dox treatment. Overexpressing GILZ by transfection was able to protect cells from apoptosis induced by Dox as measured by caspase activation, Annexin V binding and morphologic changes. Western blot analyses indicate that GILZ overexpression prevented cytochrome c release from mitochondria and cleavage of caspase-3. When bcl-2 family proteins were examined, we found that GILZ overexpression causes induction of the pro-survival protein Bcl-xL. Since siRNA against Bcl-xL reverses GC induced cytoprotection, Bcl-xL induction represents an important event in GILZ-induced cytoprotection. Our data suggest that GILZ functions as a cytoprotective gene in cardiomyocytes. - Highlights: • Corticosteroids act as a cytoprotective agent in cardiomyocytes • Corticosteroids induce GILZ expression in cardiomyocytes • Elevated GILZ results in resistance against apoptosis induced by doxorubicin • GILZ induces Bcl-xL protein without inducing Bcl-xL mRNA.

  20. Use of human stem cell derived cardiomyocytes to examine sunitinib mediated cardiotoxicity and electrophysiological alterations

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, J.D., E-mail: jennifer.cohen@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Babiarz, J.E., E-mail: joshua.babiarz@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Abrams, R.M., E-mail: rory.abrams@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Guo, L., E-mail: liang.guo@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Kameoka, S., E-mail: sei.kameoka@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Chiao, E., E-mail: eric.chiao@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Taunton, J., E-mail: taunton@cmp.ucsf.edu [Howard Hughes Medical Institute, Cellular and Molecular Pharmacology, University California San Francisco, San Francisco, CA 94158 (United States); Kolaja, K.L., E-mail: kyle.kolaja@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States)

    2011-11-15

    Sunitinib, an oral tyrosine kinase inhibitor approved to treat advanced renal cell carcinoma and gastrointestinal stroma tumor, is associated with clinical cardiac toxicity. Although the precise mechanism of sunitinib cardiotoxicity is not known, both the key metabolic energy regulator, AMP-activated protein kinase (AMPK), and ribosomal S 6 kinase (RSK) have been hypothesized as causative, albeit based on rodent models. To study the mechanism of sunitinib-mediated cardiotoxicity in a human model, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) having electrophysiological and contractile properties of native cardiac tissue were investigated. Sunitinib was cardiotoxic in a dose-dependent manner with an IC{sub 50} in the low micromolar range, observed by a loss of cellular ATP, an increase in oxidized glutathione, and induction of apoptosis in iPSC-CMs. Pretreatment of iPSC-CMs with AMPK activators AICAR or metformin, increased the phosphorylation of pAMPK-T172 and pACC-S79, but only marginally attenuated sunitinib mediated cell death. Furthermore, additional inhibitors of AMPK were not directly cytotoxic to iPSC-CMs up to 250 {mu}M concentrations. Inhibition of RSK with a highly specific, irreversible, small molecule inhibitor (RSK-FMK-MEA) did not induce cytotoxicity in iPSC-CMs below 250 {mu}M. Extensive electrophysiological analysis of sunitinib and RSK-FMK-MEA mediated conduction effects were performed. Taken together, these findings suggest that inhibition of AMPK and RSK are not a major component of sunitinib-induced cardiotoxicity. Although the exact mechanism of cardiotoxicity of sunitinib is not known, it is likely due to inhibition of multiple kinases simultaneously. These data highlight the utility of human iPSC-CMs in investigating the potential molecular mechanisms underlying drug-induced cardiotoxicity. -- Highlights: Black-Right-Pointing-Pointer Cytoxic effect of sunitinib on human stem cell derived cardiomyocytes Black

  1. File list: His.CDV.10.AllAg.Cardiomyocytes [Chip-atlas[Archive

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  8. Functional Differences in Engineered Myocardium from Embryonic Stem Cell-Derived versus Neonatal Cardiomyocytes

    NARCIS (Netherlands)

    Feinberg, Adam W.; Ripplinger, Crystal M.; van der Meer, Peter; Sheehy, Sean P.; Domian, Ibrahim; Chien, Kenneth R.; Parker, Kevin Kit

    2013-01-01

    Stem cell-derived cardiomyocytes represent unique tools for cell-and tissue-based regenerative therapies, drug discovery and safety, and studies of fundamental heart-failure mechanisms. However, the degree to which stem cell-derived cardiomyocytes compare to mature cardiomyocytes is often debated. W

  9. Age Related Bioenergetics Profiles in Isolated Rat Cardiomyocytes Using Extracellular Flux Analyses.

    Directory of Open Access Journals (Sweden)

    Kennedy S Mdaki

    Full Text Available Mitochondrial dysfunction is increasingly recognized and studied as a mediator of heart disease. Extracellular flux analysis (XF has emerged as a powerful tool to investigate cellular bioenergetics in the context of cardiac health and disease, however its use and interpretation requires improved understanding of the normal metabolic differences in cardiomyocytes (CM at various stages of maturation. This study standardized XF analyses methods (mitochondrial stress test, glycolytic stress test and palmitate oxidation test and established age related differences in bioenergetics profiles of healthy CMs at newborn (NB1, weaning (3WK, adult (10WK and aged (12-18MO time points. Findings show that immature CMs demonstrate a more robust and sustained glycolytic capacity and a relative inability to oxidize fatty acids when compared to older CMs. The study also highlights the need to recognize the contribution of CO2 from the Krebs cycle as well as lactate from anaerobic glycolysis to the proton production rate before interpreting glycolytic capacity in CMs. Overall, this study demonstrates that caution should be taken to assure that translatable developmental time points are used to investigate mitochondrial dysfunction as a cause of cardiac disease. Specifically, XF analysis of newborn CMs should be reserved to study fetal/neonatal disease and older CMs (≥10 weeks should be used to investigate adult disease pathogenesis. Knowledge gained will aid in improved investigation of developmentally programmed heart disease and stress the importance of discerning maturational differences in bioenergetics when developing mitochondrial targeted preventative and therapeutic strategies for cardiac disease.

  10. Age Related Bioenergetics Profiles in Isolated Rat Cardiomyocytes Using Extracellular Flux Analyses.

    Science.gov (United States)

    Mdaki, Kennedy S; Larsen, Tricia D; Weaver, Lucinda J; Baack, Michelle L

    2016-01-01

    Mitochondrial dysfunction is increasingly recognized and studied as a mediator of heart disease. Extracellular flux analysis (XF) has emerged as a powerful tool to investigate cellular bioenergetics in the context of cardiac health and disease, however its use and interpretation requires improved understanding of the normal metabolic differences in cardiomyocytes (CM) at various stages of maturation. This study standardized XF analyses methods (mitochondrial stress test, glycolytic stress test and palmitate oxidation test) and established age related differences in bioenergetics profiles of healthy CMs at newborn (NB1), weaning (3WK), adult (10WK) and aged (12-18MO) time points. Findings show that immature CMs demonstrate a more robust and sustained glycolytic capacity and a relative inability to oxidize fatty acids when compared to older CMs. The study also highlights the need to recognize the contribution of CO2 from the Krebs cycle as well as lactate from anaerobic glycolysis to the proton production rate before interpreting glycolytic capacity in CMs. Overall, this study demonstrates that caution should be taken to assure that translatable developmental time points are used to investigate mitochondrial dysfunction as a cause of cardiac disease. Specifically, XF analysis of newborn CMs should be reserved to study fetal/neonatal disease and older CMs (≥10 weeks) should be used to investigate adult disease pathogenesis. Knowledge gained will aid in improved investigation of developmentally programmed heart disease and stress the importance of discerning maturational differences in bioenergetics when developing mitochondrial targeted preventative and therapeutic strategies for cardiac disease. PMID:26872351

  11. Changes in the profile of NO synthases affect coronary blood flow autoregulation and myocardial contractile activity during restraint stress in rats.

    Science.gov (United States)

    Solodkov, A P; Lazuko, S S; Knyazev, E N; Nechaev, I N; Krainova, N A

    2014-12-01

    The efficiency of autoregulation of the coronary blood flow and contractile activity of the myocardium in the presence of inhibitors of constitutive and inducible NO synthases was studied in rats exposed to 6-h restraint stress. Intracoronary administration of S-methylisothiourea (10 μmol/liter), but not L-NAME (60 μmol/liter) fully prevented post-stress increase in the volume coronary blood flow rate, intensity of heart perfusion, and reduction of ventricular developed pressure at all levels of perfusion pressure. Real-time PCR showed 6-fold increased expression of inducible NO-synthase mRNA in the heart tissue against the background of unchanged expression of neuronal and endothelial NO synthases and 2-3-fold elevated content of transcripts of stress-inducible genes Hspa1a and Hspbp1. It was shown that the hypotension of coronary vessels and reduced contractile function of the myocardium are related to NO production by inducible NO synthase in endotheliocytes of coronary vessels and cardiomyocytes. PMID:25430647

  12. Dietary levels of acrylamide affect rat cardiomyocyte properties.

    Science.gov (United States)

    Walters, Brandan; Hariharan, Venkatesh; Huang, Hayden

    2014-09-01

    The toxic effects of acrylamide on cytoskeletal integrity and ion channel balance is well-established in many cell types, but there has been little examination regarding the effects of acrylamide on primary cardiomyocytes, despite the importance of such components in their function. Furthermore, acrylamide toxicity is generally examined using concentrations higher than those found in vivo under starch-rich diets. Accordingly, we sought to characterize the dose-dependent effects of acrylamide on various properties, including cell morphology, contraction patterns, and junctional connexin 43 staining, in primary cardiomyocytes. We show that several days exposure to 1-100 μM acrylamide resulted in altered morphology, irregular contraction patterns, and an increase in the amount of immunoreactive signal for connexin 43 at cell junctions. We conclude that dietary levels of acrylamide may alter cellular function with prolonged exposure, in primary cardiomyocytes.

  13. Metabolism: flow and contractility of the Langendorff heart

    NARCIS (Netherlands)

    H. Stam (Hans)

    1978-01-01

    textabstractThis thesis reviews current literature and describes experimental studies on the regulation and modification of coronary flow and contractility in isolated rat hearts. In chapter I and introduction is given to the problems of fatty acid toxicity and myocardial function. Coronary flow rat

  14. Myocardial contractile function in survived neonatal piglets after cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Popov Aron-Frederik

    2010-11-01

    Full Text Available Abstract Background Hemodynamic function may be depressed in the early postoperative stages after cardiac surgery. The aim of this study was the analysis of the myocardial contractility in neonates after cardiopulmonary bypass (CPB and mild hypothermia. Methods Three indices of left ventricular myocardial contractile function (dP/dt, (dP/dt/P, and wall thickening were studied up to 6 hours after CPB in neonatal piglets (CPB group; n = 4. The contractility data were analysed and then compared to the data of newborn piglets who also underwent median thoracotomy and instrumentation for the same time intervals but without CPB (non-CPB group; n = 3. Results Left ventricular dP/dtmax and (dP/dtmax/P remained stable in CPB group, while dP/dtmax decreased in non-CPB group 5 hours postoperatively (1761 ± 205 mmHg/s at baseline vs. 1170 ± 205 mmHg/s after 5 h; p max and (dP/dtmax/P there were no statistically significant differences between the two groups. Comparably, although myocardial thickening decreased in the non-CPB group the differences between the two groups were not statistically significant. Conclusions The myocardial contractile function in survived neonatal piglets remained stable 6 hours after cardiopulmonary bypass and mild hypothermia probably due to regional hypercontractility.

  15. Clinical Relationship between Steatocholecystitis and Gallbladder Contractility Measured by Cholescintigraphy

    Directory of Open Access Journals (Sweden)

    Chang Seok Bang

    2015-01-01

    Full Text Available Objective. Contractility of gallbladder is known to be decreased in fatty gallbladder diseases. However, clinical estimation data about this relationship is still lacking. The aim of this study was to investigate the association between steatocholecystitis and contractility of gallbladder. Methods. Patients with cholecystitis (steatocholecystitis versus nonsteatocholecystitis who underwent cholescintigraphy before cholecystectomy were retrospectively evaluated in a single teaching hospital of Korea. The association of steatocholecystitis with contractility of gallbladder, measured by preoperative cholescintigraphy, was assessed by univariable and multivariable analysis. Results. A total of 432 patients were finally enrolled (steatocholecystitis versus nonsteatocholecystitis; 75 versus 357, calculous versus acalculous cholecystitis; 316 versus 116. In the multivariable analysis, age (OR: 0.94, 95% CI: 0.90–0.99, P=0.01 and total serum cholesterol (OR: 1.02, 95% CI: 1.01–1.04, P=0.04 were related to steatocholecystitis in patients with acalculous cholecystitis. Only age (OR: 0.97, 95% CI: 0.94–0.99, P=0.004 was significantly related to steatocholecystitis in patients with calculous cholecystitis. However, ejection fraction of gallbladder reflecting contractility measured by cholescintigraphy was not related to steatocholecystitis irrespective of presence of gallbladder stone in patients with cholecystitis. Conclusion. Ejection fraction of gallbladder measured by cholescintigraphy cannot be used for the detection or confirmation of steatocholecystitis.

  16. Spatio-temporal changes of lymphatic contractility and drainage patterns following lymphadenectomy in mice.

    Directory of Open Access Journals (Sweden)

    Sunkuk Kwon

    Full Text Available OBJECTIVE: To investigate the redirection of lymphatic drainage post-lymphadenectomy using non-invasive near-infrared fluorescence (NIRF imaging, and to subsequently assess impact on metastasis. BACKGROUND: Cancer-acquired lymphedema arises from dysfunctional fluid transport after lymphadenectomy performed for staging and to disrupt drainage pathways for regional control of disease. However, little is known about the normal regenerative processes of the lymphatics in response to lymphadenectomy and how these responses can be accelerated, delayed, or can impact metastasis. METHODS: Changes in lymphatic "pumping" function and drainage patterns were non-invasively and longitudinally imaged using NIRF lymphatic imaging after popliteal lymphadenectomy in mice. In a cohort of mice, B16F10 melanoma was inoculated on the dorsal aspect of the paw 27 days after lymphadenectomy to assess how drainage patterns affect metastasis. RESULTS: NIRF imaging demonstrates that, although lymphatic function and drainage patterns change significantly in early response to popliteal lymph node (PLN removal in mice, these changes are transient and regress dramatically due to a high regenerative capacity of the lymphatics and co-opting of collateral lymphatic pathways around the site of obstruction. Metastases followed the pattern of collateral pathways and could be detected proximal to the site of lymphadenectomy. CONCLUSIONS: Both lymphatic vessel regeneration and co-opting of contralateral vessels occur following lymphadenectomy, with contractile function restored within 13 days, providing a basis for preclinical and clinical investigations to hasten lymphatic repair and restore contractile lymphatic function after surgery to prevent cancer-acquired lymphedema. Patterns of cancer metastasis after lymphadenectomy were altered, consistent with patterns of re-directed lymphatic drainage.

  17. Cardiomyocyte Triglyceride Accumulation and Reduced Ventricular Function in Mice with Obesity Reflect Increased Long Chain Fatty Acid Uptake and De Novo Fatty Acid Synthesis

    Directory of Open Access Journals (Sweden)

    Fengxia Ge

    2012-01-01

    Full Text Available A nonarteriosclerotic cardiomyopathy is increasingly seen in obese patients. Seeking a rodent model, we studied cardiac histology, function, cardiomyocyte fatty acid uptake, and transporter gene expression in male C57BL/6J control mice and three obesity groups: similar mice fed a high-fat diet (HFD and db/db and ob/ob mice. At sacrifice, all obesity groups had increased body and heart weights and fatty livers. By echocardiography, ejection fraction (EF and fractional shortening (FS of left ventricular diameter during systole were significantly reduced. The Vmax for saturable fatty acid uptake was increased and significantly correlated with cardiac triglycerides and insulin concentrations. Vmax also correlated with expression of genes for the cardiac fatty acid transporters Cd36 and Slc27a1. Genes for de novo fatty acid synthesis (Fasn, Scd1 were also upregulated. Ten oxidative phosphorylation pathway genes were downregulated, suggesting that a decrease in cardiomyocyte ATP synthesis might explain the decreased contractile function in obese hearts.

  18. Sexual Dysfunction and Infertility

    Science.gov (United States)

    ... Sexual dysfunction is a problem in a person’s sexual desire, arousal, or orgasm. Sexual dysfunction is common. It ... find they have times when they have less sexual desire and satisfaction because of emotional distress or the ...

  19. Erectile Dysfunction (ED)

    Science.gov (United States)

    ... age. Is erectile dysfunction just a part of old age? Erectile dysfunction doesn't have to be a ... episode of impotence Feeling stressed, including stress from work or family situations Being troubled by problems in ...

  20. Up-regulation of alpha-smooth muscle actin in cardiomyocytes from non-hypertrophic and non-failing transgenic mouse hearts expressing N-terminal truncated cardiac troponin I

    Directory of Open Access Journals (Sweden)

    Stephanie Kern

    2014-01-01

    Full Text Available We previously reported that a restrictive N-terminal truncation of cardiac troponin I (cTnI-ND is up-regulated in the heart in adaptation to hemodynamic stresses. Over-expression of cTnI-ND in the hearts of transgenic mice revealed functional benefits such as increased relaxation and myocardial compliance. In the present study, we investigated the subsequent effect on myocardial remodeling. The alpha-smooth muscle actin (α-SMA isoform is normally expressed in differentiating cardiomyocytes and is a marker for myocardial hypertrophy in adult hearts. Our results show that in cTnI-ND transgenic mice of between 2 and 3 months of age (young adults, a significant level of α-SMA is expressed in the heart as compared with wild-type animals. Although blood vessel density was increased in the cTnI-ND heart, the mass of smooth muscle tissue did not correlate with the increased level of α-SMA. Instead, immunocytochemical staining and Western blotting of protein extracts from isolated cardiomyocytes identified cardiomyocytes as the source of increased α-SMA in cTnI-ND hearts. We further found that while a portion of the up-regulated α-SMA protein was incorporated into the sarcomeric thin filaments, the majority of SMA protein was found outside of myofibrils. This distribution pattern suggests dual functions for the up-regulated α-SMA as both a contractile component to affect contractility and as possible effector of early remodeling in non-hypertrophic, non-failing cTnI-ND hearts.

  1. Cyclic GMP signaling in cardiomyocytes modulates fatty acid trafficking and prevents triglyceride accumulation.

    Science.gov (United States)

    Khairallah, Ramzi J; Khairallah, Maya; Gélinas, Roselle; Bouchard, Bertrand; Young, Martin E; Allen, Bruce G; Lopaschuk, Gary D; Deschepper, Christian F; Des Rosiers, Christine

    2008-08-01

    While the balance between carbohydrates and fatty acids for energy production appears to be crucial for cardiac homeostasis, much remains to be learned about the molecular mechanisms underlying this relationship. Given the reported benefits of cGMP signaling on the myocardium, we investigated the impact of its chronic activation on cardiac energy metabolism using mice overexpressing a constitutively active cytoplasmic guanylate cyclase (GC(+/0)) in cardiomyocytes. Ex vivo working GC(+/0) heart perfusions with (13)C-labeled substrates revealed an altered pattern of exogenous substrate fuel selection compared to controls, namely a 38+/-9% lower contribution of exogenous fatty acids to acetyl-CoA formation, while that of carbohydrates remains unchanged despite a two-fold increase in glycolysis. The lower contribution of exogenous fatty acids to energy production is not associated with changes in energy demand or supply (contractile function, oxygen consumption, tissue acetyl-CoA or CoA levels, citric acid cycle flux rate) or in the regulation of beta-oxidation (acetyl-CoA carboxylase activity, tissue malonyl-CoA levels). However, GC(+/0) hearts show a two-fold increase in the incorporation of exogenous oleate into triglycerides. Furthermore, the following molecular data are consistent with a concomitant increase in triglyceride hydrolysis: (i) increased abundance of hormone sensitive lipase (HSL) protein (24+/-11%) and mRNA (22+/-4%) as well as (ii) several phosphorylation events related to HSL inhibitory (AMPK) and activation (ERK 1/2) sites, which should contribute to enhance its activity. These changes in exogenous fatty acid trafficking in GC(+/0) hearts appear to be functionally relevant, as demonstrated by their resistance to fasting-induced triglyceride accumulation. While the documented metabolic profile of GC(+/0) mouse hearts is partly reminiscent of hypertrophied hearts, the observed changes in lipid trafficking have not been previously documented, and may

  2. Identification of cardiomyocyte nuclei and assessment of ploidy for the analysis of cell turnover

    International Nuclear Information System (INIS)

    Assays to quantify myocardial renewal rely on the accurate identification of cardiomyocyte nuclei. We previously 14C birth dated human cardiomyocytes based on the nuclear localization of cTroponins T and I. A recent report by Kajstura et al. suggested that cTroponin I is only localized to the nucleus in a senescent subpopulation of cardiomyocytes, implying that 14C birth dating of cTroponin T and I positive cell populations underestimates cardiomyocyte renewal in humans. We show here that the isolation of cell nuclei from the heart by flow cytometry with antibodies against cardiac Troponins T and I, as well as pericentriolar material 1 (PCM-1), allows for isolation of close to all cardiomyocyte nuclei, based on ploidy and marker expression. We also present a reassessment of cardiomyocyte ploidy, which has important implications for the analysis of cell turnover, and iododeoxyuridine (IdU) incorporation data. These data provide the foundation for reliable analysis of cardiomyocyte turnover in humans.

  3. Common marmoset embryonic stem cell can differentiate into cardiomyocytes

    International Nuclear Information System (INIS)

    Common marmoset monkeys have recently attracted much attention as a primate research model, and are preferred to rhesus and cynomolgus monkeys due to their small bodies, easy handling and efficient breeding. We recently reported the establishment of common marmoset embryonic stem cell (CMESC) lines that could differentiate into three germ layers. Here, we report that our CMESC can also differentiate into cardiomyocytes and investigated their characteristics. After induction, FOG-2 was expressed, followed by GATA4 and Tbx20, then Nkx2.5 and Tbx5. Spontaneous beating could be detected at days 12-15. Immunofluorescent staining and ultrastructural analyses revealed that they possessed characteristics typical of functional cardiomyocytes. They showed sinus node-like action potentials, and the beating rate was augmented by isoproterenol stimulation. The BrdU incorporation assay revealed that CMESC-derived cardiomyocytes retained a high proliferative potential for up to 24 weeks. We believe that CMESC-derived cardiomyocytes will advance preclinical studies in cardiovascular regenerative medicine

  4. Contracting cardiomyocytes in hydrophobic room-temperature ionic liquid

    International Nuclear Information System (INIS)

    Highlights: ► Biocompatible room-temperature ionic liquid was applied on beating cardiomyocyte. ► The lifetime of beating cardiomyocytes was depended on anion functional group. ► A longer lifetime was recorded for no functional group on alkyl chain on their anion. ► Amino group on alkyl chain and fluorine in anion induced fatal condition changes. ► We reported liquid electrolyte interface to stimulate cardiomyocytes. -- Abstract: Room-temperature ionic liquids (RTILs) are drawing attention as a new class of nonaqueous solvents to replace organic and aqueous solvents for chemical processes in the liquid phase at room temperature. The RTILs are notable for their characteristics of nonvolatility, extremely low vapor pressure, electric conductivity, and incombustibility. These distinguished properties of RTILs have brought attention to them in applications with biological cells and tissue in vacuum environment for scanning electron microscopy, and in microfluidic devices for micro-total analysis system (micro-TAS). Habitable RTILs could increase capability of nonaqueous micro-TAS for living cells. Some RTILs seemed to have the capability to replace water in biological applications. However, these RTILs had been applied to just supplemental additives for biocompatible test, to fixed cells as a substitute for an aqueous solution, and to simple molecules. None of RTILs in which directly soaks a living cell culture. Therefore, we demonstrated the design of RTILs for a living cell culture and a liquid electrolyte to stimulate contracting cardiomyocytes using the RTILs. We assessed the effect of RTILs on the cardiomyocytes using the beating lifetime to compare the applicability of RTILs for biological applications. Frequent spontaneous contractions of cardiomyocytes were confirmed in amino acid anion RTILs [P8,8,8,8][Leu] and [P8,8,8,8][Ala], phosphoric acid derivatives [P8,8,8,8][MeO(H)PO2], and [P8,8,8,8][C7CO2]. The anion type of RTILs had influence on

  5. Coordinating cardiomyocyte interactions to direct ventricular chamber morphogenesis.

    Science.gov (United States)

    Han, Peidong; Bloomekatz, Joshua; Ren, Jie; Zhang, Ruilin; Grinstein, Jonathan D; Zhao, Long; Burns, C Geoffrey; Burns, Caroline E; Anderson, Ryan M; Chi, Neil C

    2016-06-29

    Many organs are composed of complex tissue walls that are structurally organized to optimize organ function. In particular, the ventricular myocardial wall of the heart comprises an outer compact layer that concentrically encircles the ridge-like inner trabecular layer. Although disruption in the morphogenesis of this myocardial wall can lead to various forms of congenital heart disease and non-compaction cardiomyopathies, it remains unclear how embryonic cardiomyocytes assemble to form ventricular wall layers of appropriate spatial dimensions and myocardial mass. Here we use advanced genetic and imaging tools in zebrafish to reveal an interplay between myocardial Notch and Erbb2 signalling that directs the spatial allocation of myocardial cells to their proper morphological positions in the ventricular wall. Although previous studies have shown that endocardial Notch signalling non-cell-autonomously promotes myocardial trabeculation through Erbb2 and bone morphogenetic protein (BMP) signalling, we discover that distinct ventricular cardiomyocyte clusters exhibit myocardial Notch activity that cell-autonomously inhibits Erbb2 signalling and prevents cardiomyocyte sprouting and trabeculation. Myocardial-specific Notch inactivation leads to ventricles of reduced size and increased wall thickness because of excessive trabeculae, whereas widespread myocardial Notch activity results in ventricles of increased size with a single-cell-thick wall but no trabeculae. Notably, this myocardial Notch signalling is activated non-cell-autonomously by neighbouring Erbb2-activated cardiomyocytes that sprout and form nascent trabeculae. Thus, these findings support an interactive cellular feedback process that guides the assembly of cardiomyocytes to morphologically create the ventricular myocardial wall and more broadly provide insight into the cellular dynamics of how diverse cell lineages organize to create form.

  6. Atrial natriuretic peptide regulates Ca channel in early developmental cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Lin Miao

    Full Text Available BACKGROUND: Cardiomyocytes derived from murine embryonic stem (ES cells possess various membrane currents and signaling cascades link to that of embryonic hearts. The role of atrial natriuretic peptide (ANP in regulation of membrane potentials and Ca(2+ currents has not been investigated in developmental cardiomyocytes. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the role of ANP in regulating L-type Ca(2+ channel current (I(CaL in different developmental stages of cardiomyocytes derived from ES cells. ANP decreased the frequency of action potentials (APs in early developmental stage (EDS cardiomyocytes, embryonic bodies (EB as well as whole embryo hearts. ANP exerted an inhibitory effect on basal I(CaL in about 70% EDS cardiomyocytes tested but only in about 30% late developmental stage (LDS cells. However, after stimulation of I(CaL by isoproterenol (ISO in LDS cells, ANP inhibited the response in about 70% cells. The depression of I(CaL induced by ANP was not affected by either Nomega, Nitro-L-Arginine methyl ester (L-NAME, a nitric oxide synthetase (NOS inhibitor, or KT5823, a cGMP-dependent protein kinase (PKG selective inhibitor, in either EDS and LDS cells; whereas depression of I(CaL by ANP was entirely abolished by erythro-9-(2-Hydroxy-3-nonyl adenine (EHNA, a selective inhibitor of type 2 phosphodiesterase(PDE2 in most cells tested. CONCLUSION/SIGNIFICANCES: Taken together, these results indicate that ANP induced depression of action potentials and I(CaL is due to activation of particulate guanylyl cyclase (GC, cGMP production and cGMP-activation of PDE2 mediated depression of adenosine 3', 5'-cyclic monophophate (cAMP-cAMP-dependent protein kinase (PKA in early cardiomyogenesis.

  7. EXPERIMENT STUDY OF CARDIOMYOCYTE APOPTOSIS AND CARDIOMYOCYTE PROLIFERATION DURING THE DEVELOPMENT OF CARDIAC HYPERTROPHY IN SPONTANEOUSLY HYPERTENSIVE RATS

    Institute of Scientific and Technical Information of China (English)

    江立生; 方宁远; 高天; 孟超

    2005-01-01

    Objective To investigate the effect and significance of cardiomyocyte apoptosis and cardiomyocyte proliferation on cardiac hypertrophy by observing the dynamic changes of them during the development of cardiac hypertrophy in spontaneously hypertensive rats (SHR). Methods Hearts were excised from SHR and Wistar-Kyoto rats(WKY) at different ages. Cardiac hypertrophic index (CHI) was calculated as the radio of heart weight to body weight; Cardiomyocyte apoptosis was identified by in situ TDT-mediated dUTP nick end labeling (TUNEL); Localization and expression of proliferating cell nuclear antigen (PCNA) were examined by immunohistochemistry. Results Compared with age-matched WKY, CHI in SHR was significantly increased at 12 weeks old and 24 weeks old (3. 604 ± 0. 089 vs 2. 997 ± 0. 166, P<0.01; 4. 156 ± 0. 385 vs 3. 119 ± 0. 208, P < 0. 01 ) ,and CHI in SHR was increased little by little with the age increasing and attained plaiform since 20 weeks old. In contrast with age-matched WKY, cardiomyocyte apoptotic index (APOI) in SHR at 12 weeks was not increased significantly (4. 248 ± 1. 592 vs 3. 678 ± 0. 856, P > 0. 05 ), but decreased markedly when their age were 24 weeks (3. 207 ± 1. 794 vs 5. 494 ± 1. 372, P <0. 05); APOI in SHR at 12 weeks old, 16 weeks old, 20 weeks old and 24weeks old were 4. 248 ± 1. 592, 5. 707 ± 1. 322, 7. 436 ± 1. 128, 3. 207 ± 1. 794, respectively. On the other hand,APOI in SHR from 12 weeks old to 20 weeks old increased gradually, and attained peak at 20 weeks old, but decreased markedly after 20 weeks old ( P <0. 01 ). Compared with age-matched WKY, the rate of cardiomyocyte PCNA positive labeling (PCNAR) in SHR at 12 weeks old and 24 weeks old didn' t have obvious difference. Conclusion Imbalance of cardiomyocyte apoptosis and cardiomyocyte proliferation existed during the development of cardiac hypertrophy in spontaneously hypertensive rats.

  8. DETRUSOR HYPERACTIVITY WITH IMPAIRED CONTRACTILE FUNCTION に類似する排尿障害を呈した神経因性膀胱症例の検討

    OpenAIRE

    安川, 元信; 百瀬, 均; 山本, 雅司; 平尾, 佳彦; 平田, 直也; 塩見, 努

    2000-01-01

    Clinical features of 21 patients with neurogenic bladder dysfunction which meeting the criteria of "detrusor hyperactivity with impaired contractile function (DHIC)" as reported by Resnick NM in 1987, were reviewed in terms of clinical symptoms, urogra- phic findings, urodynamic findings, and treatment. Chief complaints of urination problems were of irritation in 14 patients (irritative group) and of obstruction in 7 patients (obstruc- tive group). Incidence of bladder deformity as a risk fac...

  9. Implementing cell contractility in filament-based cytoskeletal models.

    Science.gov (United States)

    Fallqvist, B

    2016-02-01

    Cells are known to respond over time to mechanical stimuli, even actively generating force at longer times. In this paper, a microstructural filament-based cytoskeletal network model is extended to incorporate this active response, and a computational study to assess the influence on relaxation behaviour was performed. The incorporation of an active response was achieved by including a strain energy function of contractile activity from the cross-linked actin filaments. A four-state chemical model and strain energy function was adopted, and generalisation to three dimensions and the macroscopic deformation field was performed by integration over the unit sphere. Computational results in MATLAB and ABAQUS/Explicit indicated an active cellular response over various time-scales, dependent on contractile parameters. Important features such as force generation and increasing cell stiffness due to prestress are qualitatively predicted. The work in this paper can easily be extended to encompass other filament-based cytoskeletal models as well. PMID:26899417

  10. Dynamic regulation of β1 subunit trafficking controls vascular contractility

    OpenAIRE

    Leo, M. Dennis; Bannister, John P.; Narayanan, Damodaran; Nair, Anitha; Grubbs, Jordan E.; Gabrick, Kyle S.; Boop, Frederick A.; Jaggar, Jonathan H.

    2014-01-01

    Plasma membrane ion channels composed of pore-forming and auxiliary subunits regulate physiological functions in virtually all cell types. A conventional view is that ion channels assemble with their auxiliary subunits prior to surface trafficking of the multiprotein complex. Arterial myocytes express large-conductance Ca2+-activated potassium (BK) channel α and auxiliary β1 subunits that modulate contractility and blood pressure and flow. The data here show that although most BKα subunits ar...

  11. High-throughput screening for modulators of cellular contractile force

    OpenAIRE

    Park, Chan Young; Zhou, Enhua H; Tambe, Dhananjay; Chen, Bohao; Lavoie, Tera; Dowell, Maria; Simeonov, Anton; Maloney, David J.; Marinkovic, Aleksandar; Tschumperlin, Daniel J.; Burger, Stephanie; Frykenberg, Matthew; Butler, James P.; Stamer, W. Daniel; Johnson, Mark

    2014-01-01

    When cellular contractile forces are central to pathophysiology, these forces comprise a logical target of therapy. Nevertheless, existing high-throughput screens are limited to upstream signaling intermediates with poorly defined relationship to such a physiological endpoint. Using cellular force as the target, here we screened libraries to identify novel drug candidates in the case of human airway smooth muscle cells in the context of asthma, and also in the case of Schlemm's canal endothel...

  12. American Ginseng Acutely Regulates Contractile Function of Rat Heart

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    Mao eJiang

    2014-03-01

    Full Text Available Chronic ginseng treatments have been purported to improve cardiac performance. However reports of acute administration of ginseng on cardiovascular function remain controversial and potential mechanisms are not clear. In this study, we examined effects of acute North American ginseng (Panax quinquefolius administration on rat cardiac contractile function by using electrocardiogram (ECG, non-invasive blood pressure measurement (BP and Langendorff isolated, spontaneously beating, perfused heart measurements (LP. Eight-week old male Sprague Dawley rats (n= 8 per group were gavaged with a single dose of water-soluble American ginseng at 300 mg/kg body weight. Heart rate and blood pressure were measured prior to and at 1 and 24 hr after gavaging (ECG and BP. Additional groups were used for each time point for Langendorff measurements. Heart rate was significantly decreased (ECG: 1 hr: 6 ± 0.2%, 24 hr: 8 ± 0.3%; BP: 1 hr: 8.8 ± 0.2%, 24 hr: 13 ± 0.4% and LP: 1 hr: 22 ± 0.4%, 24 hr: 19 ± 0.4% in rats treated with water-soluble ginseng compared with pre or control measures. An initial marked decrease in left ventricular developed pressure was observed in LP hearts but blood pressure changes were not observed in BP group. A direct inhibitory effect of North American ginseng was observed on cardiac contractile function in LP rats and on fluorescence measurement of intracellular calcium transient in freshly isolated cardiac myocytes when exposed to ginseng (1 µg/ml and 10 µg/ml. Collectively these data present evidence of depressed cardiac contractile function by acute administration of North American ginseng in rat. This acute reduction in cardiac contractile function appears to be intrinsic to the myocardium.

  13. Structure and Functional Characteristics of Rat’s Left Ventricle Cardiomyocytes under Antiorthostatic Suspension of Various Duration and Subsequent Reloading

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    I. V. Ogneva

    2012-01-01

    Full Text Available The goal of the research was to identify the structural and functional characteristics of the rat's left ventricle under antiorthostatic suspension within 1, 3, 7 and 14 days, and subsequent 3 and 7-day reloading after a 14-day suspension. The transversal stiffness of the cardiomyocyte has been determined by the atomic force microscopy, cell respiration—by polarography and proteins content—by Western blotting. Stiffness of the cortical cytoskeleton increases as soon as one day after the suspension and increases up to the 14th day, and starts decreasing during reloading, reaching the control level after 7 days. The stiffness of the contractile apparatus and the intensity of cell respiration also increases. The content of non-muscle isoforms of actin in the cytoplasmic fraction of proteins does not change during the whole experiment, as does not the beta-actin content in the membrane fraction. The content of gamma-actin in the membrane fraction correlates with the change in the transversal stiffness of the cortical cytoskeleton. Increased content of alpha-actinin-1 and alpha-actinin-4 in the membrane fraction of proteins during the suspension is consistent with increased gamma-actin content there. The opposite direction of change of alpha-actinin-1 and alpha-actinin-4 content suggests their involvement into the signal pathways.

  14. Embryonic Stem Cell-Derived Cardiomyocyte Heterogeneity and the Isolation of Immature and Committed Cells for Cardiac Remodeling and Regeneration

    Directory of Open Access Journals (Sweden)

    Kenneth R. Boheler

    2011-01-01

    Full Text Available Pluripotent stem cells represent one promising source for cell replacement therapy in heart, but differentiating embryonic stem cell-derived cardiomyocytes (ESC-CMs are highly heterogeneous and show a variety of maturation states. In this study, we employed an ESC clonal line that contains a cardiac-restricted ncx1 promoter-driven puromycin resistance cassette together with a mass culture system to isolate ESC-CMs that display traits characteristic of very immature CMs. The cells display properties of proliferation, CM-restricted markers, reduced mitochondrial mass, and hypoxia-resistance. Following transplantation into rodent hearts, bioluminescence imaging revealed that immature cells, but not more mature CMs, survived for at least one month following injection. These data and comparisons with more mature cells lead us to conclude that immature hypoxia resistant ESC-CMs can be isolated in mass in vitro and, following injection into heart, form grafts that may mediate long-term recovery of global and regional myocardial contractile function following infarction.

  15. A new system for profiling drug-induced calcium signal perturbation in human embryonic stem cell-derived cardiomyocytes.

    Science.gov (United States)

    Lewis, Kimberley J; Silvester, Nicole C; Barberini-Jammaers, Steven; Mason, Sammy A; Marsh, Sarah A; Lipka, Magdalena; George, Christopher H

    2015-03-01

    The emergence of human stem cell-derived cardiomyocyte (hSCCM)-based assays in the cardiovascular (CV) drug discovery sphere requires the development of improved systems for interrogating the rich information that these cell models have the potential to yield. We developed a new analytical framework termed SALVO (synchronization, amplitude, length, and variability of oscillation) to profile the amplitude and temporal patterning of intra- and intercellular calcium signals in hSCCM. SALVO quantified drug-induced perturbations in the calcium signaling "fingerprint" in spontaneously contractile hSCCM. Multiparametric SALVO outputs were integrated into a single index of in vitro cytotoxicity that confirmed the rank order of perturbation as astemizole > thioridazine > cisapride > flecainide > valdecoxib > sotalol > nadolol ≈ control. This rank order of drug-induced Ca(2+) signal disruption is in close agreement with the known arrhythmogenic liabilities of these compounds in humans. Validation of the system using a second set of compounds and hierarchical cluster analysis demonstrated the utility of SALVO to discriminate drugs based on their mechanisms of action. We discuss the utility of this new mechanistically agnostic system for the evaluation of in vitro drug cytotoxicity in hSCCM syncytia and the potential placement of SALVO in the early stage drug screening framework. PMID:25367900

  16. A New System for Profiling Drug-Induced Calcium Signal Perturbation in Human Embryonic Stem Cell–Derived Cardiomyocytes

    Science.gov (United States)

    Lewis, Kimberley J.; Silvester, Nicole C.; Barberini-Jammaers, Steven; Mason, Sammy A.; Marsh, Sarah A.; Lipka, Magdalena

    2015-01-01

    The emergence of human stem cell–derived cardiomyocyte (hSCCM)–based assays in the cardiovascular (CV) drug discovery sphere requires the development of improved systems for interrogating the rich information that these cell models have the potential to yield. We developed a new analytical framework termed SALVO (synchronization, amplitude, length, and variability of oscillation) to profile the amplitude and temporal patterning of intra- and intercellular calcium signals in hSCCM. SALVO quantified drug-induced perturbations in the calcium signaling “fingerprint” in spontaneously contractile hSCCM. Multiparametric SALVO outputs were integrated into a single index of in vitro cytotoxicity that confirmed the rank order of perturbation as astemizole > thioridazine > cisapride > flecainide > valdecoxib > sotalol > nadolol ≈ control. This rank order of drug-induced Ca2+ signal disruption is in close agreement with the known arrhythmogenic liabilities of these compounds in humans. Validation of the system using a second set of compounds and hierarchical cluster analysis demonstrated the utility of SALVO to discriminate drugs based on their mechanisms of action. We discuss the utility of this new mechanistically agnostic system for the evaluation of in vitro drug cytotoxicity in hSCCM syncytia and the potential placement of SALVO in the early stage drug screening framework. PMID:25367900

  17. Effect of hepatocyte growth factor and angiotensin II on rat cardiomyocyte hypertrophy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ai-Lan [Department of Cardiology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Ou, Cai-Wen [The Fourth Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); He, Zhao-Chu [Department of Cardiology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Liu, Qi-Cai [Experimental Medical Research Center, Guangzhou Medical University, Guangzhou (China); Dong, Qi [Department of Physiology, Guangzhou Medical University, Guangzhou (China); Chen, Min-Sheng [Guangzhou Key Laboratory of Cardiovascular Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou (China)

    2012-10-15

    Angiotensin II (Ang II) plays an important role in cardiomyocyte hypertrophy. The combined effect of hepatocyte growth factor (HGF) and Ang II on cardiomyocytes is unknown. The present study was designed to determine the effect of HGF on cardiomyocyte hypertrophy and to explore the combined effect of HGF and Ang II on cardiomyocyte hypertrophy. Primary cardiomyocytes were isolated from neonatal rat hearts and cultured in vitro. Cells were treated with Ang II (1 µM) alone, HGF (10 ng/mL) alone, and Ang II (1 µM) plus HGF (10 ng/mL) for 24, 48, and 72 h. The amount of [{sup 3}H]-leucine incorporation was then measured to evaluate protein synthesis. The mRNA levels of β-myosin heavy chain and atrial natriuretic factor were determined by real-time PCR to evaluate the presence of fetal phenotypes of gene expression. The cell size of cardiomyocytes was also studied. Ang II (1 µM) increased cardiomyocyte hypertrophy. Similar to Ang II, treatment with 1 µM HGF promoted cardiomyocyte hypertrophy. Moreover, the combination of 1 µM Ang II and 10 ng/mL HGF clearly induced a combined pro-hypertrophy effect on cardiomyocytes. The present study demonstrates for the first time a novel, combined effect of HGF and Ang II in promoting cardiomyocyte hypertrophy.

  18. Effect of long-term partial bladder outlet obstruction on caldesmon isoforms and their correlation with contractile function

    Institute of Scientific and Technical Information of China (English)

    Lin YANG; Da-lin Hei; Shu WANG; He-peng CHENG; Xin-yang WANG

    2008-01-01

    Aim: In the present study, we investigate the expression of caldesmon (CAD) isoforms in rabbit detrusor smooth muscles (DSM) during the progression of partial bladder outlet obstruction and relate them with the time course of obstruction. Methods: Detrusor samples were obtained from the bladders of rabbits with partial bladder outlet obstruction and sham-operated control rabbits after 1, 2, 4, and 8 weeks of obstruction. Contractile responses to field stimulation and carbachol were determined in the isolated bladder strips. Western blotting was used to determine the relative levels of CaD isoform expression at the protein levels. Results: The contractile responses decreased progressively over the course of obstruction. The expression of 1-CaD increased significantly to approximately the same extent as the 1-4-week obstructed groups and further in the 8-week ob-structed group. The expression of h-CaD increased in all of the obstructed bladders, but at significantly higher levels in the 1-2-week obstructed bladders compared to the control and 4-8-week obstructed bladders. Conclusions: The changes in the isoforms of CaD may be part of the molecular mechanism for bladder compensa-tion following partial bladder outlet obstruction. The overexpression of 1-CaD and the h-CaD/1-CaD ratio could be markers for the status of DSM remodeling and dysfunction.

  19. IP3 receptors regulate vascular smooth muscle contractility and hypertension

    Science.gov (United States)

    Lin, Qingsong; Zhao, Guiling; Fang, Xi; Peng, Xiaohong; Tang, Huayuan; Wang, Hong; Jing, Ran; Liu, Jie; Ouyang, Kunfu

    2016-01-01

    Inositol 1, 4, 5-trisphosphate receptor–mediated (IP3R-mediated) calcium (Ca2+) release has been proposed to play an important role in regulating vascular smooth muscle cell (VSMC) contraction for decades. However, whether and how IP3R regulates blood pressure in vivo remains unclear. To address these questions, we have generated a smooth muscle–specific IP3R triple-knockout (smTKO) mouse model using a tamoxifen-inducible system. In this study, the role of IP3R-mediated Ca2+ release in adult VSMCs on aortic vascular contractility and blood pressure was assessed following tamoxifen induction. We demonstrated that deletion of IP3Rs significantly reduced aortic contractile responses to vasoconstrictors, including phenylephrine, U46619, serotonin, and endothelin 1. Deletion of IP3Rs also dramatically reduced the phosphorylation of MLC20 and MYPT1 induced by U46619. Furthermore, although the basal blood pressure of smTKO mice remained similar to that of wild-type controls, the increase in systolic blood pressure upon chronic infusion of angiotensin II was significantly attenuated in smTKO mice. Taken together, our results demonstrate an important role for IP3R-mediated Ca2+ release in VSMCs in regulating vascular contractility and hypertension.

  20. Collective cancer cell invasion induced by coordinated contractile stresses.

    Science.gov (United States)

    Jimenez Valencia, Angela M; Wu, Pei-Hsun; Yogurtcu, Osman N; Rao, Pranay; DiGiacomo, Josh; Godet, Inês; He, Lijuan; Lee, Meng-Horng; Gilkes, Daniele; Sun, Sean X; Wirtz, Denis

    2015-12-22

    The physical underpinnings of fibrosarcoma cell dissemination from a tumor in a surrounding collagen-rich matrix are poorly understood. Here we show that a tumor spheroid embedded in a 3D collagen matrix exerts large contractile forces on the matrix before invasion. Cell invasion is accompanied by complex spatially and temporally dependent patterns of cell migration within and at the surface of the spheroids that are fundamentally different from migratory patterns of individual fibrosarcoma cells homogeneously distributed in the same type of matrix. Cells display a continuous transition from a round morphology at the spheroid core, to highly aligned elongated morphology at the spheroid periphery, which depends on both β1-integrin-based cell-matrix adhesion and myosin II/ROCK-based cell contractility. This isotropic-to-anisotropic transition corresponds to a shift in migration, from a slow and unpolarized movement at the core, to a fast, polarized and persistent one at the periphery. Our results also show that the ensuing collective invasion of fibrosarcoma cells is induced by anisotropic contractile stresses exerted on the surrounding matrix.

  1. Recovery in skeletal muscle contractile function after prolonged hindlimb immobilization

    Science.gov (United States)

    Fitts, R. H.; Brimmer, C. J.

    1985-01-01

    The effect of three-month hindlimb immobilization (IM) in rats on contractile properties of slow-twitch soleus (SOL), fast-twitch extensor digitorum longus, and fast-twitch superficial region of the vastus lateralis were measured after 0, 14, 28, 60, and 90 days of recovery on excized, horizontally suspended muscles stimulated electrically to maximal twitch tension. IM caused decreases in muscle-to-body weight ratios for all muscles, with no complete recovery even after 90 days. The contractile properties of the fast-twitch muscles were less affected by IM than those of the slow-twitch SOL. The SOL isometric twitch duration was shortened, due to reduced contraction and half-relaxation time, both of which returned to control levels after 14 days of recovery. The peak tetanic tension, P(O), g/sq cm,, decreased with IM by 46 percent in the SOL, but recovered by the 28th day. The maximum shortening velocity was not altered by IM in any of the muscles. Thus, normal contractile function could recover after prolonged limb IM.

  2. Role of intrinsic aerobic capacity and ventilator-induced diaphragm dysfunction

    OpenAIRE

    Sollanek, Kurt J.; Smuder, Ashley J.; Wiggs, Michael P; Morton, Aaron B.; Koch, Lauren G.; Britton, Steven L.; Powers, Scott K.

    2015-01-01

    Prolonged mechanical ventilation (MV) leads to rapid diaphragmatic atrophy and contractile dysfunction, which is collectively termed “ventilator-induced diaphragm dysfunction” (VIDD). Interestingly, endurance exercise training prior to MV has been shown to protect against VIDD. Further, recent evidence reveals that sedentary animals selectively bred to possess a high aerobic capacity possess a similar skeletal muscle phenotype to muscles from endurance trained animals. Therefore, we tested th...

  3. Adiponectin downregulation is associated with volume overload-induced myocyte dysfunction in rats

    OpenAIRE

    Wang, Li-li; Miller, Dori; Wanders, Desiree; Nanayakkara, Gayani; Amin, Rajesh; Judd, Robert; Morrison, Edward E.; Zhong, Ju-ming

    2015-01-01

    Aim: Adiponectin has been reported to exert protective effects during pathological ventricular remodeling, but the role of adiponectin in volume overload-induced heart failure remains unclear. In this study we investigated the effect of adiponectin on cardiac myocyte contractile dysfunction following volume overload in rats. Methods: Volume overload was surgically induced in rats by infrarenal aorta-vena cava fistula. The rats were intravenously administered adenoviral adiponectin at 2-, 6- a...

  4. [The cardioprotective action of the anticonvulsant preparation sodium valproate in disorders of cardiac contractile function caused by acute myocardial infarct in rats].

    Science.gov (United States)

    Belkina, L M; Korchazhkina, N B; Kamskova, Iu G; Fomin, N A

    1997-01-01

    The preventive and therapeutical effects of sodium valproate (SV), 200 mg/kg, on cardiac contractile disorders (developed pressure, rate-pressure products, dp/dt) were studied in rats having 2-day myocardial infarction (MI). The postinfarction rather than preinfarction use of SV substantially restricted the depressed resting left ventricular function. Given by two regimens, SV increased cardiac resistance to the maximum isometric load induced by 60-sec ligation of the ascending aorta. The cardioprotective effect of the drug was shown due to its positive chronotropic action rather than its inotropic one. Thus, SV may be used as an effective drug for the prevention and treatment of postinfarct cardiac dysfunctions. PMID:9235532

  5. Myocardin-related transcription factor-A-overexpressing bone marrow stem cells protect cardiomyocytes and alleviate cardiac damage in a rat model of acute myocardial infarction.

    Science.gov (United States)

    Zhong, Ze; Hu, Jia-Qing; Wu, Xin-Dong; Sun, Yong; Jiang, Jun

    2015-09-01

    Myocardin-related transcription factor-A (MRTF-A) can transduce biomechanical and humoral signals, which can positively modulate cardiac damage induced by acute myocardial infarction (AMI). In the clinic, bone marrow stem cell (BMSC) therapy is being increasingly utilized for AMI; however, the effects of BMSC transplantation remain to be optimized. Therefore, a novel strategy to enhance BMSC‑directed myocardial repair is particularly important. The present study was performed to assess the efficacy of MRTF‑A-overexpressing BMSCs in a rat model of AMI. Primary cardiomyocytes were prepared from neonatal Sprague-Dawley rats and BMSCs were isolated from male Sprague-Dawley rats (aged 8-12 weeks). Annexin V-phycoerythrin/7-actinomycin D staining was used to evaluate BMSC and cardiomyocyte survival after exposure to hydrogen peroxide in vitro. B-cell lymphoma 2 (Bcl-2) protein expression was measured by flow cytometric and western blot analyses. The effects of MRTF-A‑overexpressing BMSCs in a rat model of AMI were investigated by hematoxylin and eosin staining and western blot analysis of Bcl-2 expression in myocardial tissue sections. MRTF-A enhanced the migration of BMSCs, and overexpression of MRTF-A in BMSCs prevented hydrogen peroxide-induced apoptosis in primary cardiomyocytes ex vivo. In addition, co-culture of cardiomyocytes with MRTF‑A-overexpressing BMSCs inhibited hydrogen peroxide-induced apoptosis and the enhanced expression of Bcl-2. Furthermore, in vivo, enhanced cell survival was observed in the MRTF-A-modified BMSC group compared with that in the control group. These observations indicated that MRTF-A-overexpressing BMSCs have the potential to exert cardioprotective effects against hydrogen peroxide-induced injury and that treatment with MRTF‑A‑modified BMSCs is able to reverse cardiac dysfunction after AMI.

  6. Myocardin-related transcription factor-A-overexpressing bone marrow stem cells protect cardiomyocytes and alleviate cardiac damage in a rat model of acute myocardial infarction.

    Science.gov (United States)

    Zhong, Ze; Hu, Jia-Qing; Wu, Xin-Dong; Sun, Yong; Jiang, Jun

    2015-09-01

    Myocardin-related transcription factor-A (MRTF-A) can transduce biomechanical and humoral signals, which can positively modulate cardiac damage induced by acute myocardial infarction (AMI). In the clinic, bone marrow stem cell (BMSC) therapy is being increasingly utilized for AMI; however, the effects of BMSC transplantation remain to be optimized. Therefore, a novel strategy to enhance BMSC‑directed myocardial repair is particularly important. The present study was performed to assess the efficacy of MRTF‑A-overexpressing BMSCs in a rat model of AMI. Primary cardiomyocytes were prepared from neonatal Sprague-Dawley rats and BMSCs were isolated from male Sprague-Dawley rats (aged 8-12 weeks). Annexin V-phycoerythrin/7-actinomycin D staining was used to evaluate BMSC and cardiomyocyte survival after exposure to hydrogen peroxide in vitro. B-cell lymphoma 2 (Bcl-2) protein expression was measured by flow cytometric and western blot analyses. The effects of MRTF-A‑overexpressing BMSCs in a rat model of AMI were investigated by hematoxylin and eosin staining and western blot analysis of Bcl-2 expression in myocardial tissue sections. MRTF-A enhanced the migration of BMSCs, and overexpression of MRTF-A in BMSCs prevented hydrogen peroxide-induced apoptosis in primary cardiomyocytes ex vivo. In addition, co-culture of cardiomyocytes with MRTF‑A-overexpressing BMSCs inhibited hydrogen peroxide-induced apoptosis and the enhanced expression of Bcl-2. Furthermore, in vivo, enhanced cell survival was observed in the MRTF-A-modified BMSC group compared with that in the control group. These observations indicated that MRTF-A-overexpressing BMSCs have the potential to exert cardioprotective effects against hydrogen peroxide-induced injury and that treatment with MRTF‑A‑modified BMSCs is able to reverse cardiac dysfunction after AMI. PMID:26135208

  7. In EXOG-depleted cardiomyocytes cell death is marked by a decreased mitochondrial reserve capacity of the electron transport chain.

    Science.gov (United States)

    Tigchelaar, Wardit; De Jong, Anne Margreet; van Gilst, Wiek H; De Boer, Rudolf A; Silljé, Herman H W

    2016-07-01

    Depletion of mitochondrial endo/exonuclease G-like (EXOG) in cultured neonatal cardiomyocytes stimulates mitochondrial oxygen consumption rate (OCR) and induces hypertrophy via reactive oxygen species (ROS). Here, we show that neurohormonal stress triggers cell death in endo/exonuclease G-like-depleted cells, and this is marked by a decrease in mitochondrial reserve capacity. Neurohormonal stimulation with phenylephrine (PE) did not have an additive effect on the hypertrophic response induced by endo/exonuclease G-like depletion. Interestingly, PE-induced atrial natriuretic peptide (ANP) gene expression was completely abolished in endo/exonuclease G-like-depleted cells, suggesting a reverse signaling function of endo/exonuclease G-like. Endo/exonuclease G-like depletion initially resulted in increased mitochondrial OCR, but this declined upon PE stimulation. In particular, the reserve capacity of the mitochondrial respiratory chain and maximal respiration were the first indicators of perturbations in mitochondrial respiration, and these marked the subsequent decline in mitochondrial function. Although pathological stimulation accelerated these processes, prolonged EXOG depletion also resulted in a decline in mitochondrial function. At early stages of endo/exonuclease G-like depletion, mitochondrial ROS production was increased, but this did not affect mitochondrial DNA (mtDNA) integrity. After prolonged depletion, ROS levels returned to control values, despite hyperpolarization of the mitochondrial membrane. The mitochondrial dysfunction finally resulted in cell death, which appears to be mainly a form of necrosis. In conclusion, endo/exonuclease G-like plays an essential role in cardiomyocyte physiology. Loss of endo/exonuclease G-like results in diminished adaptation to pathological stress. The decline in maximal respiration and reserve capacity is the first sign of mitochondrial dysfunction that determines subsequent cell death. PMID:27417117

  8. Endothelium protectant and contractile effects of the antivaricose principle escin in rat aorta.

    Science.gov (United States)

    Carrasco, Omar F; Vidrio, Horacio

    2007-07-01

    The triterpene saponin escin is the active component of the extract of seeds of Aesculus hippocastanum used in the treatment of chronic venous insufficiency. Escin is also used experimentally to increase membrane permeability in isolated cells. Since endothelial dysfunction is postulated to be involved in venous insufficiency, the possible endothelium-protectant effect of escin was explored in rat aortic rings, a model widely used to study such effects with cardiovascular agents. Escin enhanced endothelium-dependent relaxation induced by acetylcholine when such relaxation had been reduced by exposure to the superoxide ion generator pyrogallol. This effect was attributed to enhanced nitric oxide production by endothelial nitric oxide synthase, a calcium-dependent enzyme, activated by the increased endothelial cell permeability to calcium induced by escin. Another effect of escin thought to contribute to its therapeutic activity is its ability to produce venous contraction. The compound was found to induce concentration-related contraction also in rat aortic rings. This response was partially inhibited by removal of the endothelium or by preincubation with indomethacin, and was completely abolished by incubation in a calcium-free perfusion fluid. Contraction was considered to be due mainly to the aforementioned effect on calcium permeability, with some mediation by release of endothelial vasoconstrictor prostanoids. It was concluded that, in rat aorta, escin possesses an endothelium-protectant action and a direct contractile effect. The former could contribute to its beneficial effect in the treatment of venous insufficiency, while the latter could constitute a limiting side effect. PMID:17512261

  9. Altered right ventricular contractile pattern after cardiac surgery: monitoring of septal function is essential.

    Science.gov (United States)

    Nguyen, Tin; Cao, Long; Movahed, Assad

    2014-10-01

    Assessment of right ventricular (RV) function is important in the management of various forms of cardiovascular disease. Accurately assessing RV volume and systolic function is a challenge in day-to-day clinical practice due to its complex geometry. Tricuspid annular plane systolic excursion (TAPSE) and systolic excursion velocity (S') have been reviewed to further assess their suitability and objectivity in evaluating RV function. Multiple studies have validated their diagnostic and prognostic values in numerous pathologic conditions. Diminished longitudinal contraction after cardiothoracic surgery is a well-known phenomenon, but it is not well validated. Despite significant reduction in RV performance along the long-axis assessed by TAPSE and S' after cardiac surgery, RV ejection fractions did not change as well as the left ventricular parameters and exercise capacity. RV contractile patterns were markedly altered with decreased longitudinal shortening and increased transverse shortening, which are likely resulted from the septal damage during cardiac surgery. The septum is essential for RV performance due to its oblique fiber orientation. This allows ventricular twisting, which is a vital mechanism against increased pulmonary vascular resistance. The septum function along with TAPSE and S' should be adequately assessed during cardiac surgery, and evidence of septal dysfunction should lead to reevaluation of myocardial protection methods. PMID:24919944

  10. Altered right ventricular contractile pattern after cardiac surgery: monitoring of septal function is essential.

    Science.gov (United States)

    Nguyen, Tin; Cao, Long; Movahed, Assad

    2014-10-01

    Assessment of right ventricular (RV) function is important in the management of various forms of cardiovascular disease. Accurately assessing RV volume and systolic function is a challenge in day-to-day clinical practice due to its complex geometry. Tricuspid annular plane systolic excursion (TAPSE) and systolic excursion velocity (S') have been reviewed to further assess their suitability and objectivity in evaluating RV function. Multiple studies have validated their diagnostic and prognostic values in numerous pathologic conditions. Diminished longitudinal contraction after cardiothoracic surgery is a well-known phenomenon, but it is not well validated. Despite significant reduction in RV performance along the long-axis assessed by TAPSE and S' after cardiac surgery, RV ejection fractions did not change as well as the left ventricular parameters and exercise capacity. RV contractile patterns were markedly altered with decreased longitudinal shortening and increased transverse shortening, which are likely resulted from the septal damage during cardiac surgery. The septum is essential for RV performance due to its oblique fiber orientation. This allows ventricular twisting, which is a vital mechanism against increased pulmonary vascular resistance. The septum function along with TAPSE and S' should be adequately assessed during cardiac surgery, and evidence of septal dysfunction should lead to reevaluation of myocardial protection methods.

  11. Simple non-invasive analysis of embryonic stem cell-derived cardiomyocytes beating in vitro

    Science.gov (United States)

    Radaszkiewicz, Katarzyna Anna; Sýkorová, Dominika; Karas, Pavel; Kudová, Jana; Kohút, Lukáš; Binó, Lucia; Večeřa, Josef; Víteček, Jan; Kubala, Lukáš; Pacherník, Jiří

    2016-02-01

    The analysis of digital video output enables the non-invasive screening of various active biological processes. For the monitoring and computing of the beating parameters of cardiomyocytes in vitro, CB Analyser (cardiomyocyte beating analyser) software was developed. This software is based on image analysis of the video recording of beating cardiomyocytes. CB Analyser was tested using cardiomyocytes derived from mouse embryonic stem cells at different stages of cardiomyogenesis. We observed that during differentiation (from day 18), the beat peak width decreased, which corresponded to the increased speed of an individual pulse. However, the beating frequency did not change. Further, the effects of epinephrine modulating mature cardiomyocyte functions were tested to validate the CB Analyser analysis. In conclusion, data show that CB Analyser is a useful tool for evaluating the functions of both developing and mature cardiomyocytes under various conditions in vitro.

  12. Ghrelin promotes differentiation of human embryonic stem cells into cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    Jin YANG; Guo-qiang LIU; Rui WEI; Wen-fang HOU; Mei-juan GAO; Ming-xia ZHU; Hai-ning WANG; Gui-an CHEN; Tian-pei HONG

    2011-01-01

    Aim:Ghrelin is involved in regulating the differentiation of mesoderm-derived precursor cells.The aim of this study was to investigate whether ghrelin modulated the differentiation of human embryonic stem (hES) cells into cardiomyocytes and,if so,whether the effect was mediated by growth hormone secretagogue receptor 1α (GHS-R1α).Methods:Cardiomyocyte differentiation from hES cells was performed according to an embryoid body (EB)-based protocol.The cumulative percentage of beating EBs was calculated.The expression of cardiac-specific markers including cardiac troponin Ⅰ (cTnl) and α-myosin heavy chain (α-MHC) was detected using RT-PCR,real-time PCR and Western blot.The dispersed beating EBs were examined using immunofluorescent staining.Results:The percentage of beating EBs and the expression of cTnl were significantly increased after ghrelin (0.1 and 1 nmol/L) added into the differentiation medium.From 6 to 18 d of differentiation,the increased expression of cTnl and α-MHC by ghrelin (1 nmol/L)was time-dependent,and in line with the alteration of the percentages of beating EBs.Furthermore,the dispersed beating EBs were double-positively immunostained with antibodies against cTnl and α-actinin.However,blockage of GHS-R1α with its specific antagonist D-[lys3]-GHRP-6 (1 μmol/L) did not alter the effects of ghrelin on cardiomyocyte differentiation.Conclusion:Our data show that ghrelin enhances the generation of cardiomyocytes from hES cells,which is not mediated via GHS-R1α.

  13. Rac1 modulates cardiomyocyte adhesion during mouse embryonic development

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Issa, Radwan, E-mail: rabuissa@umich.edu

    2015-01-24

    Highlights: • Conditional knockout of Rac1 using Nkx2.5 Cre line is lethal at E13.5. • The myocardium of the mutant is thin and disorganized. • The phenotype is not due to cardiomyocyte low proliferation or apoptosis. • The phenotype is due to specific defect in cardiomyocyte adhesion. - Abstract: Rac1, a member of the Rho subfamily of small GTPases, is involved in morphogenesis and differentiation of many cell types. Here we define a role of Rac1 in cardiac development by specifically deleting Rac1 in the pre-cardiac mesoderm using the Nkx2.5-Cre transgenic driver line. Rac1-conditional knockout embryos initiate heart development normally until embryonic day 11.5 (E11.5); their cardiac mesoderm is specified, and the heart tube is formed and looped. However, by E12.5-E13.5 the mutant hearts start failing and embryos develop edema and hemorrhage which is probably the cause for the lethality observed soon after. The hearts of Rac1-cKO embryos exhibit disorganized and thin myocardial walls and defects in outflow tract alignment. No significant differences of cardiomyocyte death or proliferation were found between developing control and mutant embryos. To uncover the role of Rac1 in the heart, E11.5 primary heart cells were cultured and analyzed in vitro. Rac1-deficient cardiomyocytes were less spread, round and loosely attached to the substrate and to each other implying that Rac1-mediated signaling is required for appropriate cell–cell and/or cellmatrix adhesion during cardiac development.

  14. Cardiomyocyte GTP Cyclohydrolase 1 Protects the Heart Against Diabetic Cardiomyopathy

    OpenAIRE

    Hsiang-En Wu; Shelley L. Baumgardt; Juan Fang; Mark Paterson; Yanan Liu; Jianhai Du; Yang Shi; Shigang Qiao; Bosnjak, Zeljko J.; Warltier, David C.; Kersten, Judy R; Zhi-Dong Ge

    2016-01-01

    Diabetic cardiomyopathy increases the risk of heart failure and death. At present, there are no effective approaches to preventing its development in the clinic. Here we report that reduction of cardiac GTP cyclohydrolase 1 (GCH1) degradation by genetic and pharmacological approaches protects the heart against diabetic cardiomyopathy. Diabetic cardiomyopathy was induced in C57BL/6 wild-type mice and transgenic mice with cardiomyocyte-specific overexpression of GCH1 with streptozotocin, and co...

  15. "Western" diet, but not high fat diet, causes maladaptation of cardiac fatty acid metabolism and cardiac dysfunction in the Wistar rat

    Science.gov (United States)

    Obesity and diabetes are associated with increased fatty acid availability in excess of fatty acid oxidation capacity. This mismatch is implicated in the pathogenesis of cardiac contractile dysfunction. We tested the hypothesis that a "western" or a high fat diet will lead to maladaptation of cardia...

  16. Western diet, but not high fat diet, causes maladaptation of cardiac fatty acid metabolism and cardiac dysfunction in the Wistar rat

    Science.gov (United States)

    Obesity and diabetes are associated with increased fatty acid availability in excess of fatty acid oxidation capacity. This mismatch is implicated in the pathogenesis of cardiac contractile dysfunction. We tested the hypothesis that a "western" or a high fat diet will lead to maladaptation of cardia...

  17. The Oxygen-Rich Postnatal Environment Induces Cardiomyocyte Cell-Cycle Arrest through DNA Damage Response

    OpenAIRE

    Bao\\xa0N. Puente; Wataru Kimura; Shalini\\xa0A. Muralidhar; Jesung Moon; James\\xa0F. Amatruda; Kate\\xa0L. Phelps; David Grinsfelder; Beverly\\xa0A. Rothermel; Rui Chen; Joseph\\xa0A. Garcia; Celio\\xa0X. Santos; SuWannee Thet; Eiichiro Mori; Michael\\xa0T. Kinter; Paul\\xa0M. Rindler

    2014-01-01

    The mammalian heart has a remarkable regenerative capacity for a short period of time after birth, after which the majority of cardiomyocytes permanently exit cell cycle. We sought to determine the primary post-natal event that results in cardiomyocyte cell-cycle arrest. We hypothesized that transition to the oxygen rich postnatal environment is the upstream signal that results in cell cycle arrest of cardiomyocytes. Here we show that reactive oxygen species (ROS), oxidative DNA damage, and D...

  18. Role of Histone Demethylases in Cardiomyocytes Induced to Hypertrophy

    Directory of Open Access Journals (Sweden)

    Wendy Rosales

    2016-01-01

    Full Text Available Epigenetic changes induced by histone demethylases play an important role in differentiation and pathological changes in cardiac cells. However, the role of the jumonji family of demethylases in the development of cardiac hypertrophy remains elusive. In this study, the presence of different histone demethylases in cardiac cells was evaluated after hypertrophy was induced with neurohormones. A cell line from rat cardiomyocytes was used as a biological model. The phenotypic profiles of the cells, as well as the expression of histone demethylases, were studied through immunofluorescence, transient transfection, western blot, and qRT-PCR analysis after inducing hypertrophy by angiotensin II and endothelin-1. An increase in fetal gene expression (ANP, BNP, and β-MHC was observed in cardiomyocytes after treatment with angiotensin II and endothelin-1. A significant increase in JMJD2A expression, but not in UTX or JMJD2C expression, was observed. When JMJD2A was overexpressed in cardiomyocytes through transient transfection, the effect of neurohormones on fetal cardiac gene expression was increased. We conclude that JMJD2A plays a principal role in the regulation of fetal cardiac genes, which increase in expression during the pathological hypertrophic process.

  19. Contractile units in disordered actomyosin bundles arise from F-actin buckling

    CERN Document Server

    Lenz, Martin; Gardel, Margaret L; Dinner, Aaron R

    2012-01-01

    Bundles of filaments and motors are central to contractility in cells. The classic example is striated muscle, where actomyosin contractility is mediated by highly organized sarcomeres which act as fundamental contractile units. However, many contractile bundles in vivo and in vitro lack sarcomeric organization. Here we propose a model for how contractility can arise in actomyosin bundles without sarcomeric organization and validate its predictions with experiments on a reconstituted system. In the model, internal stresses in frustrated arrangements of motors with diverse velocities cause filaments to buckle, leading to overall shortening. We describe the onset of buckling in the presence of stochastic actin-myosin detachment and predict that buckling-induced contraction occurs in an intermediate range of motor densities. We then calculate the size of the "contractile units" associated with this process. Consistent with these results, our reconstituted actomyosin bundles contract at relatively high motor dens...

  20. EGCG inhibits cardiomyocyte apoptosis in pressure overload-induced cardiac hypertrophy and protects cardiomyocytes from oxidative stress in rats

    Institute of Scientific and Technical Information of China (English)

    Rui SHENG; Zhen-lun GU; Mei-lin XIE; Wen-xuan ZHOU; Ci-yi GUO

    2007-01-01

    Aim: To investigate the effects of epigallocatechin gallate (EGCG) on pressure overload and hydrogen peroxide (H2O2) induced cardiac myocyte apoptosis. Methods: Cardiac hypertrophy was established in rats by abdominal aortic constriction. EGCG 25, 50 and 100 mg/kg were administered intragastrically (ig). Cultured newborn rat cardiomyocytes were preincubated with EGCG, and oxidative stress injury was induced by H2O2. Results: In cardiac hypertrophy induced by AC in rats, relative to the model group, EGCG 25, 50 and 100 mg/kg ig for 6weeks dose-dependently reduced systolic blood pressure (SBP) and heart weight indices, decreased malondialdehyde (MDA) content, and increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activity, both in serum and in the myocardium. Also, treatment with EGCG 50 and 100 mg/kg markedly improved cardiac structure and inhibited fibrosis in HE and van Gieson (VG) stain, and reduced apoptotic myocytes in the hypertrophic myocardium detected by terminal transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay. Inthe Western blot analysis, EGCG significantly inhibited pressure overload-inducedp53 increase and bcl-2 decrease. In H2O2-induced cardiomyocyte injury, when preincubated with myocytes for 6-48 h, EGCG 12.5-200 mg/L increased cell viability determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay. EGCG also attenuated H2O2-induced lactate dehydrogenase (LDH) release and MDA formation. Meanwhile, EGCG 50 and 100 mg/L significantly inhibited the cardiomyocyte apoptotic rate in flow cytometry. Conclusion: EGCG inhibits cardiac myocyte apoptosis and oxidative stress in pressure overload in-duced cardiac hypertrophy. Also, EGCG prevented cardiomyocyte apoptosis from oxidative stress in vitro. The mechanism might be related to the inhibitory effects of EGCG on p53 induction and bcl-2 decrease.

  1. Improvement of cardiac contractile function by peptide-based inhibition of NF-κB in the utrophin/dystrophin-deficient murine model of muscular dystrophy

    Directory of Open Access Journals (Sweden)

    Guttridge Denis C

    2011-05-01

    that NBD can significantly improve cardiac contractile dysfunction in the dko mouse model of DMD and may thus provide a novel therapeutic treatment for heart failure.

  2. A comparison of the contractile properties of myometrium from singleton and twin pregnancies.

    Directory of Open Access Journals (Sweden)

    Peter Turton

    Full Text Available OBJECTIVE: Over half of twin pregnancies in US and UK deliver prematurely but the reasons for this are unclear. The contractility of myometrium from twin pregnancies has not been directly investigated. The objective of this research was to determine if there are differences in the contractile activity and response to oxytocin, between myometrium from singleton and twin pregnancies, across a range of gestational ages. Furthermore, we wished to determine if contractile activity correlates with increasing level of stretch, using neonatal birth weights as a marker of uterine stretch. METHODS: This was an in vitro, laboratory based study of myometrial contractility in women pregnant with one or two babies, using biopsies obtained from non-labouring women undergoing Caesarean section. Spontaneous, oxytocin-stimulated and depolarization induced contractile activity was compared. RESULTS: Direct measurements of myometrial contractility under controlled conditions show that the frequency of contractions and responses to oxytocin are significantly increased in twins compared to singletons. The duration of contraction however was significantly reduced. We find that contractile activity correlates with increasing levels of stretch, using neonatal birth weights as a surrogate for uterine stretch, with response to oxytocin being significantly positively correlated with birth weight. CONCLUSIONS: We have found significant differences in contractile properties between myometrium from singleton and twin pregnancies and that increasing uterine stretch can alter the contractile properties of myometrium. We discuss the implication of these findings to preterm delivery and future studies.

  3. Multiple mechanisms involved in oxytocin-induced modulation of myometrial contractility

    Institute of Scientific and Technical Information of China (English)

    Anatoly SHMYGOL; Joanna GULLAM; Andrew BLANKS; Steven THORNTON

    2006-01-01

    Oxytocin is a small peptide hormone with multiple sites of action in human body.It regulates a large number of reproduction-related processes in all species.Particularly important is its ability to stimulate uterine contractility.This is achieved by multiple mechanisms involving sarcoplasmic reticulum Ca2+ release and sensitization of the contractile apparatus to Ca2+.In this paper,we review the data published by US and other groups on oxytocin-induced modulation of uterine contractility.We conclude that sensitization of contractile apparatus to Ca2+ is the most relevant physiological effect of oxytocin on human myometrium.

  4. Dexamethasone Induces Cardiomyocyte Terminal Differentiation via Epigenetic Repression of Cyclin D2 Gene.

    Science.gov (United States)

    Gay, Maresha S; Dasgupta, Chiranjib; Li, Yong; Kanna, Angela; Zhang, Lubo

    2016-08-01

    Dexamethasone treatment of newborn rats inhibited cardiomyocyte proliferation and stimulated premature terminal differentiation of cardiomyocytes in the developing heart. Yet mechanisms remain undetermined. The present study tested the hypothesis that the direct effect of glucocorticoid receptor-mediated epigenetic repression of cyclin D2 gene in the cardiomyocyte plays a key role in the dexamethasone-mediated effects in the developing heart. Cardiomyocytes were isolated from 2-day-old rats. Cells were stained with a cardiomyocyte marker α-actinin and a proliferation marker Ki67. Cyclin D2 expression was evaluated by Western blot and quantitative real-time polymerase chain reaction. Promoter methylation of CcnD2 was determined by methylated DNA immunoprecipitation (MeDIP). Overexpression of Cyclin D2 was conducted by transfection of FlexiCcnD2 (+CcnD2) construct. Treatment of cardiomyocytes isolated from newborn rats with dexamethasone for 48 hours significantly inhibited cardiomyocyte proliferation with increased binucleation and decreased cyclin D2 protein abundance. These effects were blocked with Ru486 (mifepristone). In addition, the dexamethasone treatment significantly increased cyclin D2 gene promoter methylation in newborn rat cardiomyocytes. 5-Aza-2'-deoxycytidine inhibited dexamethasone-mediated promoter methylation, recovered dexamethasone-induced cyclin D2 gene repression, and blocked the dexamethasone-elicited effects on cardiomyocyte proliferation and binucleation. In addition, the overexpression of cyclin D2 restored the dexamethasone-mediated inhibition of proliferation and increase in binucleation in newborn rat cardiomyocytes. The results demonstrate that dexamethasone acting on glucocorticoid receptors has a direct effect and inhibits proliferation and stimulates premature terminal differentiation of cardiomyocytes in the developing heart via epigenetic repression of cyclin D2 gene. PMID:27302109

  5. Influence of the cardiac myosin hinge region on contractile activity.

    Science.gov (United States)

    Margossian, S S; Krueger, J W; Sellers, J R; Cuda, G; Caulfield, J B; Norton, P; Slayter, H S

    1991-06-01

    The participation of cardiac myosin hinge in contractility was investigated by in vitro motility and ATPase assays and by measurements of sarcomere shortening. The effect on contractile activity was analyzed using an antibody directed against a 20-amino acid peptide within the hinge region of myosin. This antibody bound specifically at the hinge at a distance of 55 nm from the S1/S2 junction, was specific to human, dog, and rat cardiac myosins, did not crossreact with gizzard or skeletal myosin, and had no effect on ATPase activity of purified S1 and myofibrils. However, it completely suppressed the movement of actin filaments in in vitro motility assays and reduced active shortening of sarcomeres of skinned cardiac myocytes by half. Suppression of motion by the anti-hinge antibody may reflect a mechanical constraint imposed by the antibody upon the mobility of the S2 region of myosin. The results suggest that the steps in the mechanochemical energy transduction can be separately influenced through S2.

  6. Resolving the role of actoymyosin contractility in cell microrheology.

    Directory of Open Access Journals (Sweden)

    Christopher M Hale

    Full Text Available Einstein's original description of Brownian motion established a direct relationship between thermally-excited random forces and the transport properties of a submicron particle in a viscous liquid. Recent work based on reconstituted actin filament networks suggests that nonthermal forces driven by the motor protein myosin II can induce large non-equilibrium fluctuations that dominate the motion of particles in cytoskeletal networks. Here, using high-resolution particle tracking, we find that thermal forces, not myosin-induced fluctuating forces, drive the motion of submicron particles embedded in the cytoskeleton of living cells. These results resolve the roles of myosin II and contractile actomyosin structures in the motion of nanoparticles lodged in the cytoplasm, reveal the biphasic mechanical architecture of adherent cells-stiff contractile stress fibers interdigitating in a network at the cell cortex and a soft actin meshwork in the body of the cell, validate the method of particle tracking-microrheology, and reconcile seemingly disparate atomic force microscopy (AFM and particle-tracking microrheology measurements of living cells.

  7. Micro-arrayed human embryonic stem cells-derived cardiomyocytes for in vitro functional assay.

    Directory of Open Access Journals (Sweden)

    Elena Serena

    Full Text Available INTRODUCTION: The heart is one of the least regenerative organs in the body and any major insult can result in a significant loss of heart cells. The development of an in vitro-based cardiac tissue could be of paramount importance for many aspects of the cardiology research. In this context, we developed an in vitro assay based on human cardiomyocytes (hCMs and ad hoc micro-technologies, suitable for several applications: from pharmacological analysis to physio-phatological studies on transplantable hCMs. We focused on the development of an assay able to analyze not only hCMs viability, but also their functionality. METHODS: hCMs were cultured onto a poly-acrylamide hydrogel with tunable tissue-like mechanical properties and organized through micropatterning in a 20×20 array. Arrayed hCMs were characterized by immunofluorescence, GAP-FRAP analyses and live and dead assay. Their functionality was evaluated monitoring the excitation-contraction coupling. RESULTS: Micropatterned hCMs maintained the expression of the major cardiac markers (cTnT, cTnI, Cx43, Nkx2.5, α-actinin and functional properties. The spontaneous contraction frequency was (0.83±0.2 Hz, while exogenous electrical stimulation lead to an increase up to 2 Hz. As proof of concept that our device can be used for screening the effects of pathological conditions, hCMs were exposed to increasing levels of H(2O(2. Remarkably, hCMs viability was not compromised with exposure to 0.1 mM H(2O(2, but hCMs contractility was dramatically suppressed. As proof of concept, we also developed a microfluidic platform to selectively treat areas of the cell array, in the perspective of performing multi-parametric assay. CONCLUSIONS: Such system could be a useful tool for testing the effects of multiple conditions on an in vitro cell model representative of human heart physiology, thus potentially helping the processes of therapy and drug development.

  8. The characteristics of action potential and nonselective cation current of cardiomyocytes in rabbit superior vena cava

    Institute of Scientific and Technical Information of China (English)

    WANG Pan; YANG XinChun; LIU XiuLan; BAO RongFeng; LIU TaiFeng

    2008-01-01

    As s special focus in initiating and maintaining atrial fibrillation (AF), cardiomyocytes in superior vena cavs (SVC) have distinctive electrophysiological characters. In this study, we found that comparing with the right atrial (RA) cardiomyoctyes, the SVC cardiomyoctyes had longer APD90 at the different basic cycle lengths; the conduction block could be observed on both RA and SVC cardiomyoctyes. A few of SVC cardiomyoctyes showed slow response action potentials with automatic activity and some others showed early afterdepolarization (EAD) spontaneously. Further more, we found that there are nonselective cation current (INs) in both SVC and RA cardiomyocytes. The peak density of INs in SVC cardiomyocytes was smaller than that in RA cardiomyocytes. Removal of extracellular divalent cation and glucose could increase INs in SVC cardiomyocytes. The agonist or the antagonist of INs may increase or decrease APD. To sum up, some SVC cardiomyocytes possess the ability of spontaneous activity; the difference of transmembrane action potentials between SVC and RA cardiomyocytes is partly because of the different density of INs between them; the agonist or the antagonist of INs can increase or decrease APD leading to the enhancement or reduction of EAD genesis in SVC cardiomyocytes. INs in rabbit myocytes is fairly similar to TRPC3 current in electrophysiological property, which might play an important role in the mechanisms of AF.

  9. Dystrophin-deficient cardiomyocytes derived from human urine: New biologic reagents for drug discovery

    Directory of Open Access Journals (Sweden)

    Xuan Guan

    2014-03-01

    Full Text Available The ability to extract somatic cells from a patient and reprogram them to pluripotency opens up new possibilities for personalized medicine. Induced pluripotent stem cells (iPSCs have been employed to generate beating cardiomyocytes from a patient's skin or blood cells. Here, iPSC methods were used to generate cardiomyocytes starting from the urine of a patient with Duchenne muscular dystrophy (DMD. Urine was chosen as a starting material because it contains adult stem cells called urine-derived stem cells (USCs. USCs express the canonical reprogramming factors c-myc and klf4, and possess high telomerase activity. Pluripotency of urine-derived iPSC clones was confirmed by immunocytochemistry, RT-PCR and teratoma formation. Urine-derived iPSC clones generated from healthy volunteers and a DMD patient were differentiated into beating cardiomyocytes using a series of small molecules in monolayer culture. Results indicate that cardiomyocytes retain the DMD patient's dystrophin mutation. Physiological assays suggest that dystrophin-deficient cardiomyocytes possess phenotypic differences from normal cardiomyocytes. These results demonstrate the feasibility of generating cardiomyocytes from a urine sample and that urine-derived cardiomyocytes retain characteristic features that might be further exploited for mechanistic studies and drug discovery.

  10. Generation and characterization of functional cardiomyocytes derived from human T cell-derived induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Tomohisa Seki

    Full Text Available Induced pluripotent stem cells (iPSCs have been proposed as novel cell sources for genetic disease models and revolutionary clinical therapies. Accordingly, human iPSC-derived cardiomyocytes are potential cell sources for cardiomyocyte transplantation therapy. We previously developed a novel generation method for human peripheral T cell-derived iPSCs (TiPSCs that uses a minimally invasive approach to obtain patient cells. However, it remained unknown whether TiPSCs with genomic rearrangements in the T cell receptor (TCR gene could differentiate into functional cardiomyocyte in vitro. To address this issue, we investigated the morphology, gene expression pattern, and electrophysiological properties of TiPSC-derived cardiomyocytes differentiated by floating culture. RT-PCR analysis and immunohistochemistry showed that the TiPSC-derived cardiomyocytes properly express cardiomyocyte markers and ion channels, and show the typical cardiomyocyte morphology. Multiple electrode arrays with application of ion channel inhibitors also revealed normal electrophysiological responses in the TiPSC-derived cardiomyocytes in terms of beating rate and the field potential waveform. In this report, we showed that TiPSCs successfully differentiated into cardiomyocytes with morphology, gene expression patterns, and electrophysiological features typical of native cardiomyocytes. TiPSCs-derived cardiomyocytes obtained from patients by a minimally invasive technique could therefore become disease models for understanding the mechanisms of cardiac disease and cell sources for revolutionary cardiomyocyte therapies.

  11. Vascular dysfunction following polymicrobial sepsis: role of pattern recognition receptors.

    Directory of Open Access Journals (Sweden)

    Stefan Felix Ehrentraut

    Full Text Available AIMS: Aim was to elucidate the specific role of pattern recognition receptors in vascular dysfunction during polymicrobial sepsis (colon ascendens stent peritonitis, CASP. METHODS AND RESULTS: Vascular contractility of C57BL/6 (wildtype mice and mice deficient for Toll-like receptor 2/4/9 (TLR2-D, TLR4-D, TLR9-D or CD14 (CD14-D was measured 18 h following CASP. mRNA expression of pro- (Tumor Necrosis Factor-α (TNFα, Interleukin (IL-1β, IL-6 and anti-inflammatory cytokines (IL-10 and of vascular inducible NO-Synthase (iNOS was determined using RT-qPCR. Wildtype mice exhibited a significant loss of vascular contractility after CASP. This was aggravated in TLR2-D mice, blunted in TLR4-D animals and abolished in TLR9-D and CD14-D animals. TNF-α expression was significantly up-regulated after CASP in wildtype and TLR2-D animals, but not in mice deficient for TLR4, -9 or CD14. iNOS was significantly up-regulated in TLR2-D animals only. TLR2-D animals showed significantly higher levels of TLR4, -9 and CD14. Application of H154-ODN, a TLR9 antagonist, attenuated CASP-induced cytokine release and vascular dysfunction in wildtype mice. CONCLUSIONS: Within our model, CD14 and TLR9 play a decisive role for the development of vascular dysfunction and thus can be effectively antagonized using H154-ODN. TLR2-D animals are more prone to polymicrobial sepsis, presumably due to up-regulation of TLR4, 9 and CD14.

  12. Myocardial Galectin-3 Expression Is Associated with Remodeling of the Pressure-Overloaded Heart and May Delay the Hypertrophic Response without Affecting Survival, Dysfunction, and Cardiac Fibrosis.

    Science.gov (United States)

    Frunza, Olga; Russo, Ilaria; Saxena, Amit; Shinde, Arti V; Humeres, Claudio; Hanif, Waqas; Rai, Vikrant; Su, Ya; Frangogiannis, Nikolaos G

    2016-05-01

    The β-galactoside-binding animal lectin galectin-3 is predominantly expressed by activated macrophages and is a promising biomarker for patients with heart failure. Galectin-3 regulates inflammatory and fibrotic responses; however, its role in cardiac remodeling remains unclear. We hypothesized that galectin-3 may be up-regulated in the pressure-overloaded myocardium and regulate hypertrophy and fibrosis. In normal mouse myocardium, galectin-3 was constitutively expressed in macrophages and was localized in atrial but not ventricular cardiomyocytes. In a mouse model of transverse aortic constriction, galectin-3 expression was markedly up-regulated in the pressure-overloaded myocardium. Early up-regulation of galectin-3 was localized in subpopulations of macrophages and myofibroblasts; however, after 7 to 28 days of transverse aortic constriction, a subset of cardiomyocytes in fibrotic areas contained large amounts of galectin-3. In vitro, cytokine stimulation suppressed galectin-3 synthesis by macrophages and cardiac fibroblasts. Correlation studies revealed that cardiomyocyte- but not macrophage-specific galectin-3 localization was associated with adverse remodeling and dysfunction. Galectin-3 knockout mice exhibited accelerated cardiac hypertrophy after 7 days of pressure overload, whereas female galectin-3 knockouts had delayed dilation after 28 days of transverse aortic constriction. However, galectin-3 loss did not affect survival, systolic and diastolic dysfunction, cardiac fibrosis, and cardiomyocyte hypertrophy in the pressure-overloaded heart. Despite its potential role as a prognostic biomarker, galectin-3 is not a critical modulator of cardiac fibrosis but may delay the hypertrophic response. PMID:26948424

  13. Sexual Dysfunction in Women

    Science.gov (United States)

    ... also cause sexual dysfunction. You may have less sexual desire during pregnancy, right after childbirth or when you are breastfeeding. After menopause many women feel less sexual desire, have vaginal dryness or have pain during sex ...

  14. Spinal Cord Dysfunction (SCD)

    Data.gov (United States)

    Department of Veterans Affairs — The Spinal Cord Dysfunction (SCD) module supports the maintenance of local and national registries for the tracking of patients with spinal cord injury and disease...

  15. Diastolic dysfunction in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Wiese, Signe; Halgreen, Hanne;

    2016-01-01

    Development of esophageal varices, ascites, and hepatic nephropathy is among the major complications of cirrhosis. The presence of cirrhotic cardiomyopathy, which includes a left ventricular diastolic dysfunction (DD), seems to deteriorate the course of the disease and the prognosis. Increased...

  16. Rat Cardiomyocytes Express a Classical Epithelial Beta-Defensin

    Directory of Open Access Journals (Sweden)

    Annika Linde

    2008-01-01

    Full Text Available Beta-defensins (BDs are classical epithelial antimicrobial peptides of immediate importance in innate host defense. Since recent studies have suggested that certain BDs are also expressed in non-traditional tissues, including whole heart homogenate and because effector molecules of innate immunity and inflammation can influence the development of certain cardiovascular disease processes, we hypothesized that BDs are produced by cardiomyocytes as a local measure of cardioprotection against danger signals. Here we report that at least one rat beta-defensin, rBD1, is expressed constitutively in cardiomyocytes specifically isolated using position-ablation-laser-microdissection (P.A.L.M. Microlaser Technologies. RT-PCR analysis showed expression of a single 318 bp transcript in adult rat heart (laser-excised cardiomyocytes and H9c2 cells (neonatal rat heart myoblasts. Moreover, the full length cDNA of rBD1 was established and translated into a putative peptide with 69 amino acid residues. The predicted amino acid sequence of the adult rat cardiac BD-1 peptide displayed 99% identity with the previously reported renal rBD1 and 88, 53, 53 and 50% identity with mouse, human, gorilla and rhesus monkey BD1 respectively. Furthermore, structural analysis of the cardiac rBD1 showed the classical six-cysteine conserved motif of the BD family with an alpha-helix and three beta-sheets. Additionally, rBD1 displayed a significantly greater number of amphoteric residues than any of the human analogs, indicating a strong pH functional dependence in the rat. We suggest that rBD1, which was initially believed to be a specific epithelium-derived peptide, may be also involved in local cardiac innate immune defense mechanisms.

  17. Effects of lengthening contraction on calcium kinetics and skeletal muscle contractility in humans

    DEFF Research Database (Denmark)

    Nielsen, J S; Madsen, K; Jørgensen, L V;

    2005-01-01

    We have tested the hypothesis that the altered muscle contractility after lengthening contractions (LC) is caused by altered calcium (Ca2+) kinetics.......We have tested the hypothesis that the altered muscle contractility after lengthening contractions (LC) is caused by altered calcium (Ca2+) kinetics....

  18. Contractility of the guinea pig bladder measured in situ and in vitro

    NARCIS (Netherlands)

    J.M. Groen (Jan); R. van Mastrigt (Ron); J.L.H.R. Bosch (Ruud)

    1994-01-01

    textabstractTo study the relative importance of neurogenic factors in detrusor contractility and to relate a total bladder in vitro contractility model to a previously described bladder wall strip model, active intravesical pressure values were compared in situ and in vitro in eight male guinea pigs

  19. Image Processing Techniques for Assessing Contractility in Isolated Neonatal Cardiac Myocytes

    Directory of Open Access Journals (Sweden)

    Carlos Bazan

    2011-01-01

    employed in determining myocyte contractility almost simultaneously with the acquisition of the Ca2+ transient and other correlates of cell contraction. The proposed methodology can be utilized to evaluate changes in contractile behavior resulting from drug intervention, disease models, transgeneity, or other common applications of neonatal cardiocytes.

  20. Transient impairments in single muscle fibre contractile function after prolonged cycling in elite endurance athletes

    DEFF Research Database (Denmark)

    Hvid, L G; Gejl, Kasper Degn; Bech, R D;

    2013-01-01

    Prolonged muscle activity impairs whole-muscle performance and function. However, little is known about the effects of prolonged muscle activity on the contractile function of human single muscle fibres. The purpose of this study was to investigate the effects of prolonged exercise and subsequent...... recovery on the contractile function of single muscle fibres obtained from elite athletes....

  1. Effects of ageing on single muscle fibre contractile function following short-term immobilisation

    DEFF Research Database (Denmark)

    Hvid, Lars G; Ortenblad, Niels; Aagaard, Per;

    2011-01-01

    Very little attention has been given to the combined effects of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile...

  2. Effect of contractile protein alterations on cardiac myofilament function in human heart failure

    NARCIS (Netherlands)

    Narolska, N.A.

    2006-01-01

    The main objective of this thesis was to elucidate the effect of translational and post-translational alterations in contractile proteins occurring during heart failure on contractile function in human cardiac tissue. Isometric force and ATPase activity measurements were performed in skinned human

  3. Hyperlipidemia and erectile dysfunction

    Institute of Scientific and Technical Information of China (English)

    Sae-ChulKim

    2000-01-01

    We have done consecutive studies to investigate the effects of impaired lipid metabolism on the contractile and relaxation response of cavernous smooth muscles and to elucidate its pathogenesis: 1 ) incidence of hyperlipidemia in impotent patients; 2) erection response to intmcavemous injection of papaverine in impotent patients with hyperlipidemia; 3) relaxation responses of isolated cavemosal smooth muscles to endothelium-independent and endothelium-dependent vasodilators in impotent patients with hypercholesterolemia or hypertriglyceridemia; 4) involvement of superoxide radical in the impaired endothelium-dependent relaxation of cavernous smooth muscle in hypercholesterolemic rabbits; 5) effects of isolated lipoproteins and triglyceride, combined oxidized LDL plus triglyceride, and combined oxidized LDL plus HDL on contractile and relaxation response of rabbit cavernous smooth muscles; 6) involvement of e-NOS in the impaired endothelium-dependent relaxation of cavernous smooth muscle in hypercholesterolemic rabbit. Hypercholesterolemia may cause impairment of endothelium-dependent relaxation. Oxidized LDL is the major causative cholesterol of the impaired relaxation response. A chain reaction, the production of superoxide radicals and functional impairment of eNOS may be a major cause of the functional impairment in the early stages of hypercholesterolemia.

  4. Immune dysfunction in cirrhosis

    OpenAIRE

    Sipeki Nóra; Antal-Szalmás Péter (1968-) (laboratóriumi szakorvos, laboratóriumi hematológus és immunológus, klinikai farmakológus szakorvos); Lakatos Péter László; Papp Mária (1975-) (belgyógyász, gasztroenterológus)

    2014-01-01

    Innate and adaptive immune dysfunction, also referred to as cirrhosis-associated immune dysfunction syndrome, is a major component of cirrhosis, and plays a pivotal role in the pathogenesis of both the acute and chronic worsening of liver function. During the evolution of the disease, acute decompensation events associated with organ failure(s), so-called acute-on chronic liver failure, and chronic decompensation with progression of liver fibrosis and also development of disease specific comp...

  5. Cell Competition Promotes Phenotypically Silent Cardiomyocyte Replacement in the Mammalian Heart

    Directory of Open Access Journals (Sweden)

    Cristina Villa del Campo

    2014-09-01

    Full Text Available Heterogeneous anabolic capacity in cell populations can trigger a phenomenon known as cell competition, through which less active cells are eliminated. Cell competition has been induced experimentally in stem/precursor cell populations in insects and mammals and takes place endogenously in early mouse embryonic cells. Here, we show that cell competition can be efficiently induced in mouse cardiomyocytes by mosaic overexpression of Myc during both gestation and adult life. The expansion of the Myc-overexpressing cardiomyocyte population is driven by the elimination of wild-type cardiomyocytes. Importantly, this cardiomyocyte replacement is phenotypically silent and does not affect heart anatomy or function. These results show that the capacity for cell competition in mammals is not restricted to stem cell populations and suggest that stimulated cell competition has potential as a cardiomyocyte-replacement strategy.

  6. Imaging alterations of cardiomyocyte cAMP microdomains in disease

    Directory of Open Access Journals (Sweden)

    Alexander eFroese

    2015-08-01

    Full Text Available 3’,5’-cyclic adenosine monophosphate (cAMP is an important second messenger which regulates heart function by acting in distinct subcellular microdomains. Recent years have provided deeper mechanistic insights into compartmentalized cAMP signaling and its link to cardiac disease. In this mini review, we summarize newest developments in this field achieved by cutting-edge biochemical and biophysical techniques. We further compile the data from different studies into a bigger picture of so far uncovered alterations in cardiomyocyte cAMP microdomains which occur in compensated cardiac hypertrophy and chronic heart failure. Finally, future research directions and translational perspectives are briefly discussed.

  7. Relationships of thigh muscle contractile and non-contractile tissue with function, strength, and age in boys with Duchenne muscular dystrophy.

    Science.gov (United States)

    Akima, Hiroshi; Lott, Donovan; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Arpan, Ishu; Bendixen, Roxanna; Lee Sweeney, H; Walter, Glenn; Vandenborne, Krista

    2012-01-01

    The purpose of this study was to assess the contractile and non-contractile content in thigh muscles of patients with Duchenne muscular dystrophy (DMD) and determine the relationship with functional abilities. Magnetic resonance images of the thigh were acquired in 28 boys with DMD and 10 unaffected boys. Muscle strength, timed functional tests, and the Brookes Lower Extremity scale were also assessed. Non-contractile content in the DMD group was significantly greater than in the control group for six muscles, including rectus femoris, biceps femoris-long head and adductor magnus. Non-contractile content in the total thigh musculature assessed by MRI correlated with the Brookes scale (r(s)=0.75) and supine-up test (r(s)=0.68), as well as other functional measures. An age-related specific torque increase was observed in the control group (r(s)=0.96), but not the DMD (r(s)=0.06). These findings demonstrate that MRI measures of contractile and non-contractile content can provide important information about disease progression in DMD. PMID:21807516

  8. Effects of coffee and caffeine on bladder dysfunction in streptozotocin-induced diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Chao-ran YI; Zhong-qing WEI; Xiang-lei DENG; Ze-yu SUN; Xing-rang LI; Cheng-gong TIAN

    2006-01-01

    Aim: To explore the effects and mechanisms of caffeine and coffee on bladder dysfunction in streptozotocin-induced diabetic rats. Methods: Sprague-Dawley male rats were divided randomly into 4 groups: control, diabetes mellitus (DM), DM with coffee treatment, and DM with caffeine treatment. The diabetic rat was induced by intraperitoneal injection of streptozotocin (60 mg/kg). After 7 weeks of treatment with coffee and caffeine, cystometrogram, contractile responses to electrical field stimulation (EFS) and acetylcholine (ACh), and cyclic AMP (cAMP) concentration of the bladder body and base were measured. Results: The bladder weight, volume threshold for micturition and post-void residual volume (PVR) in the diabetic rats were significantly higher compared to those in the control animals. Coffee or caffeine treatment significantly reduced the bladder weight, bladder capacity and PVR in the diabetic rats. DM caused significant decreases in cAMP concentration of the bladder and coffee and caffeine caused upregulation of cAMP content in the diabetic bladder. In addition, coffee and caffeine tended to normalize the altered detrusor contractile responses to EFS and ACh in the diabetic rats. Conclusion: These results indicate that caffeine and coffee may have beneficial effects on bladder dysfunction in the early stage of diabetes by increasing cAMP content in the lower urinary tract, recovering the micturition reflex and improving the detrusor contractility.

  9. Detecting cardiac contractile activity in the early mouse embryo using multiple modalities

    Directory of Open Access Journals (Sweden)

    Chiann-mun eChen

    2015-01-01

    Full Text Available The heart is one of the first organs to develop during mammalian embryogenesis. In the mouse, it starts to form shortly after gastrulation, and is derived primarily from embryonic mesoderm. The embryonic heart is unique in having to perform a mechanical contractile function while undergoing complex morphogenetic remodelling. Approaches to imaging the morphogenesis and contractile activity of the developing heart are important in understanding not only how this remodelling is controlled but also the origin of congenital heart defects. Here, we describe approaches for visualising contractile activity in the developing mouse embryo, using brightfield time lapse microscopy and confocal microscopy of calcium transients. We describe an algorithm for enhancing this image data and quantifying contractile activity from it. Finally we describe how atomic force microscopy can be used to record contractile activity prior to it being microscopically visible.

  10. Understanding greater cardiomyocyte functions on aligned compared to random carbon nanofibers in PLGA

    Directory of Open Access Journals (Sweden)

    Asiri AM

    2014-12-01

    Full Text Available Abdullah M Asiri,1 Hadi M Marwani,1 Sher Bahadar Khan,1 Thomas J Webster1,2 1Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia; 2Department of Chemical Engineering, Northeastern University, Boston, MA, USA Abstract: Previous studies have demonstrated greater cardiomyocyte density on carbon nanofibers (CNFs aligned (compared to randomly oriented in poly(lactic-co-glycolic acid (PLGA composites. Although such studies demonstrated a closer mimicking of anisotropic electrical and mechanical properties for such aligned (compared to randomly oriented CNFs in PLGA composites, the objective of the present in vitro study was to elucidate a deeper mechanistic understanding of how cardiomyocyte densities recognize such materials to respond more favorably. Results showed lower wettability (greater hydrophobicity of CNFs embedded in PLGA compared to pure PLGA, thus providing evidence of selectively lower wettability in aligned CNF regions. Furthermore, the results correlated these changes in hydrophobicity with increased adsorption of fibronectin, laminin, and vitronectin (all proteins known to increase cardiomyocyte adhesion and functions on CNFs in PLGA compared to pure PLGA, thus providing evidence of selective initial protein adsorption cues on such CNF regions to promote cardiomyocyte adhesion and growth. Lastly, results of the present in vitro study further confirmed increased cardiomyocyte functions by demonstrating greater expression of important cardiomyocyte biomarkers (such as Troponin-T, Connexin-43, and α-sarcomeric actin when CNFs were aligned compared to randomly oriented in PLGA. In summary, this study provided evidence that cardiomyocyte functions are improved on CNFs aligned in PLGA compared to randomly oriented in PLGA since CNFs are more hydrophobic than PLGA and attract the adsorption of key proteins (fibronectin, laminin, and vironectin that are known to promote cardiomyocyte adhesion

  11. Procedures for rat in situ skeletal muscle contractile properties.

    Science.gov (United States)

    MacIntosh, Brian R; Esau, Shane P; Holash, R John; Fletcher, Jared R

    2011-01-01

    There are many circumstances where it is desirable to obtain the contractile response of skeletal muscle under physiological circumstances: normal circulation, intact whole muscle, at body temperature. This includes the study of contractile responses like posttetanic potentiation, staircase and fatigue. Furthermore, the consequences of disease, disuse, injury, training and drug treatment can be of interest. This video demonstrates appropriate procedures to set up and use this valuable muscle preparation. To set up this preparation, the animal must be anesthetized, and the medial gastrocnemius muscle is surgically isolated, with the origin intact. Care must be taken to maintain the blood and nerve supplies. A long section of the sciatic nerve is cleared of connective tissue, and severed proximally. All branches of the distal stump that do not innervate the medial gastrocnemius muscle are severed. The distal nerve stump is inserted into a cuff lined with stainless steel stimulating wires. The calcaneus is severed, leaving a small piece of bone still attached to the Achilles tendon. Sonometric crystals and/or electrodes for electromyography can be inserted. Immobilization by metal probes in the femur and tibia prevents movement of the muscle origin. The Achilles tendon is attached to the force transducer and the loosened skin is pulled up at the sides to form a container that is filled with warmed paraffin oil. The oil distributes heat evenly and minimizes evaporative heat loss. A heat lamp is directed on the muscle, and the muscle and rat are allowed to warm up to 37°C. While it is warming, maximal voltage and optimal length can be determined. These are important initial conditions for any experiment on intact whole muscle. The experiment may include determination of standard contractile properties, like the force-frequency relationship, force-length relationship, and force-velocity relationship. With care in surgical isolation, immobilization of the origin of the

  12. Sarcomeric Z-disc: A center of signaling transduction in cardiomyocytes%肌节Z盘:心肌细胞的信号转导中心

    Institute of Scientific and Technical Information of China (English)

    余志斌

    2012-01-01

    Sarcomere represents the fundamental contractile unit of cardiomyocytes. The lateral boundaries of a single sarcomere are built up by Z-discs, which also represent a key interface between the contractile apparatus and the cytoskeleton. Z-discs provide a backbone for the insertions of actin-based thin filaments as well as titin and nebulin/nebulette. Z-discs can also transmit forces generated within the sarcomere to the extracellular matrix. In addition to the cytoskeletal proteins, Z-discs are composed of a large number of adaptor proteins and other molecules. These proteins can bind or recruit ion channels, Na-Ca exchanger, protein kinases, protein phosphatases, phosphodiesterases, proteases, acetylases and deacetylases, which are involved in multiple signal transduction pathways. Z-discs also sense the stress and strain from sar-comeres and drive nuclear translocation of some shuttle proteins that modulate gene expression. Transverse tubules are invaginations of the surface membrane that form a complex network surrounding myofi-brils. Therefore, the transverse tubule network is a structure that allows rapid propagation of excitation and biochemical signals into Z-discs. In summary, Z-discs are a bona fide center of signal transduction in cardiomyocytes.%近年发现,除形成Z盘的骨架蛋白外,还有许多蛋白定位于Z盘,如结合或募集离子通道、Na-Ca交换体、蛋白激酶、蛋白磷酸酶、磷酸二酯酶、蛋白水解酶、组蛋白乙酰转移酶与组蛋白脱乙酰化酶等的蛋白分子,参与了多条信号转导通道的信号调节作用.Z盘还能感知心肌细胞的应力与应变,使结合其上的一些蛋白向核转位,调节基因表达.另外,T管穿行于Z盘之间,可使各类调节信号能快速发挥作用.因此,Z盘部位实质上成为心肌细胞中的信号转导中心.

  13. The benefit of enhanced contractility in the infarct borderzone: A virtual experiment.

    Directory of Open Access Journals (Sweden)

    Zhihong eZhang

    2012-04-01

    Full Text Available A. Objectives Contractile function in the normally perfused infarct borderzone (BZ is depressed. However, the impact of reduced BZ contractility on left ventricular (LV pump function is unknown. As a consequence, there have been no therapies specifically designed to improve BZ contractility. We tested the hypothesis that an improvement in borderzone contractility will improve LV pump function.B. Methods From a previously reported study, magnetic resonance (MRI images with non-invasive tags were used to calculate 3D myocardial strain in five sheep 16 weeks after anteroapical myocardial infarction. Animal specific finite element (FE models were created using MRI data and LV pressure obtained at early diastolic filling. Analysis of borderzone function using those FE models has been previously reported. Chamber stiffness, pump function (Starling’s law and stress in the fiber, cross fiber and circumferential directions were calculated. Animal-specific FE models were performed for three cases: a impaired BZ contractility (INJURED; b BZ contractility fully restored (100% BZ IMPROVEMENT; or c BZ contractility partially restored (50% BZ IMPROVEMENT.C. Results 100% BZ IMPROVEMENT and 50% BZ IMPROVEMENT both caused an upward shift in the Starling relationship, resulting in a large (36% and 26% increase in stroke volume at LVPED = 20 mm Hg (8.0 ml, p<0.001. Moreover, there were a leftward shift in the end systolic pressure volume relationship, resulting in a 7% and 5% increase in LVPES at 110 mm Hg (7.7 ml, p<0.005. It showed that even 50% BZ IMPROVEMENT was sufficient to drive much of the calculated increase in function. D. Conclusions. Improved borderzone contractility has a beneficial effect on LV pump function. Partial improvement of borderzone contractility was sufficient to drive much of the calculated increase in function. Therapies specifically designed to improve borderzone contractility should be developed.

  14. Cardiomyocyte MEA data analysis (CardioMDA--a novel field potential data analysis software for pluripotent stem cell derived cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Paruthi Pradhapan

    Full Text Available Cardiac safety pharmacology requires in-vitro testing of all drug candidates before clinical trials in order to ensure they are screened for cardio-toxic effects which may result in severe arrhythmias. Micro-electrode arrays (MEA serve as a complement to current in-vitro methods for drug safety testing. However, MEA recordings produce huge volumes of data and manual analysis forms a bottleneck for high-throughput screening. To overcome this issue, we have developed an offline, semi-automatic data analysis software, 'Cardiomyocyte MEA Data Analysis (CardioMDA', equipped with correlation analysis and ensemble averaging techniques to improve the accuracy, reliability and throughput rate of analysing human pluripotent stem cell derived cardiomyocyte (CM field potentials. With the program, true field potential and arrhythmogenic complexes can be distinguished from one another. The averaged field potential complexes, analysed using our software to determine the field potential duration, were compared with the analogous values obtained from manual analysis. The reliability of the correlation analysis algorithm, evaluated using various arrhythmogenic and morphology changing signals, revealed a mean sensitivity and specificity of 99.27% and 94.49% respectively, in determining true field potential complexes. The field potential duration of the averaged waveforms corresponded well to the manually analysed data, thus demonstrating the reliability of the software. The software has also the capability to create overlay plots for signals recorded under different drug concentrations in order to visualize and compare the magnitude of response on different ion channels as a result of drug treatment. Our novel field potential analysis platform will facilitate the analysis of CM MEA signals in semi-automated way and provide a reliable means of efficient and swift analysis for cardiomyocyte drug or disease model studies.

  15. Contractile reaction of isolated frog aorta after X-irradiation

    International Nuclear Information System (INIS)

    The action of X-rays (50 kV, filtered by 0.3 mm Al) on helical strip of frog aorta (rana esculenta) has been investigated. The isolated preparations have a stable basal tone and are radio-sensitive to X-rays which induce reversible, dose-dependent, contractile responses. After repeated irradiational tachyphylaxis appears. The threshold doses are about 250 R at 3 to 6 kR/min, antiadrenergic (phentolamine, propranolol), anticholinergic (atropin), antihistaminic (Neo-Bridal) and serotoninergic (Deseril) drugs have no visible influence on the X-ray induced reaction, i.e. these action mechanisms of the irradiation-induced contraction do not seem probable. Theophylline and cAMP inhibit the X-ray contraction probably non-specifically. Indometacin also inhibits the X-ray contraction: this suggests participation of prostaglandin-mechanism on the contraction of frog aorta after irradiation. (orig.)

  16. High-throughput screening for modulators of cellular contractile force

    CERN Document Server

    Park, Chan Young; Tambe, Dhananjay; Chen, Bohao; Lavoie, Tera; Dowell, Maria; Simeonov, Anton; Maloney, David J; Marinkovic, Aleksandar; Tschumperlin, Daniel J; Burger, Stephanie; Frykenberg, Matthew; Butler, James P; Stamer, W Daniel; Johnson, Mark; Solway, Julian; Fredberg, Jeffrey J; Krishnan, Ramaswamy

    2014-01-01

    When cellular contractile forces are central to pathophysiology, these forces comprise a logical target of therapy. Nevertheless, existing high-throughput screens are limited to upstream signaling intermediates with poorly defined relationship to such a physiological endpoint. Using cellular force as the target, here we screened libraries to identify novel drug candidates in the case of human airway smooth muscle cells in the context of asthma, and also in the case of Schlemm's canal endothelial cells in the context of glaucoma. This approach identified several drug candidates for both asthma and glaucoma. We attained rates of 1000 compounds per screening day, thus establishing a force-based cellular platform for high-throughput drug discovery.

  17. Cardiac contractility, central haemodynamics and blood pressure regulation during semistarvation

    DEFF Research Database (Denmark)

    Stokholm, K H; Breum, L; Astrup, A

    1991-01-01

    pressure (BP) declined. The fall in BP was caused by the reduction in cardiac output as the total peripheral resistance was unchanged. Finally, the decline in total blood volume was not significant. These findings together with a reduction in heart rate indicated that a reduced sympathetic tone via......Eight obese patients were studied before and after 2 weeks of treatment by a very-low-calorie diet (VLCD). Cardiac output and central blood volume (pulmonary blood volume and left atrial volume) were determined by indicator dilution (125I-albumin) and radionuclide angiocardiography (first pass...... and equilibrium technique by [99Tcm]red blood cells). Cardiac output decreased concomitantly with the reduction in oxygen uptake as the calculated systemic arteriovenous difference of oxygen was unaltered. There were no significant decreases in left ventricular contractility indices, i.e. the ejection fraction...

  18. Contractile 5-HT1B receptors in human cerebral arteries

    DEFF Research Database (Denmark)

    Nilsson, T; Longmore, J; Shaw, D;

    1999-01-01

    immunocytochemistry with antibodies selective for human 5-HT1B and human 5-HT1D receptors and also studied the contractile effects of a range of 5-HT receptor agonists and antagonists in HCA. 2 Immunocytochemistry of cerebral arteries showed dense 5-HT1B receptor immunoreactivity (but no 5-HT1D receptor......1 The cerebrovascular receptor(s) that mediates 5-hydroxytryptamine (5-HT)-induced vasoconstriction in human cerebral arteries (HCA)has proven difficult to characterize, yet these are essential in migraine. We have examined 5-HT receptor subtype distribution in cerebral blood vessels by...... immunoreactivity) within the smooth muscle wall of the HCA. The endothelial cell layer was well preserved and weak 5-HT1B receptor immunoreactivity was present. 3 Pharmacological experiments on HCA with intact endothelium showed that 5-carboxamidotryptamine was significantly more potent than alpha-methyl-5-HT, 2...

  19. Gene expression analyses implicate an alternative splicing program in regulating contractile gene expression and serum response factor activity in mice.

    Directory of Open Access Journals (Sweden)

    Twishasri Dasgupta

    Full Text Available Members of the CUG-BP, Elav-like family (CELF regulate alternative splicing in the heart. In MHC-CELFΔ transgenic mice, CELF splicing activity is inhibited postnatally in heart muscle via expression of a nuclear dominant negative CELF protein under an α-myosin heavy chain promoter. MHC-CELFΔ mice develop dilated cardiomyopathy characterized by alternative splicing defects, enlarged hearts, and severe contractile dysfunction. In this study, gene expression profiles in the hearts of wild type, high- and low-expressing lines of MHC-CELFΔ mice were compared using microarrays. Gene ontology and pathway analyses identified contraction and calcium signaling as the most affected processes. Network analysis revealed that the serum response factor (SRF network is highly affected. Downstream targets of SRF were up-regulated in MHC-CELFΔ mice compared to the wild type, suggesting an increase in SRF activity. Although SRF levels remained unchanged, known inhibitors of SRF activity were down-regulated. Conversely, we found that these inhibitors are up-regulated and downstream SRF targets are down-regulated in the hearts of MCKCUG-BP1 mice, which mildly over-express CELF1 in heart and skeletal muscle. This suggests that changes in SRF activity are a consequence of changes in CELF-mediated regulation rather than a secondary result of compensatory pathways in heart failure. In MHC-CELFΔ males, where the phenotype is only partially penetrant, both alternative splicing changes and down-regulation of inhibitors of SRF correlate with the development of cardiomyopathy. Together, these results strongly support a role for CELF-mediated alternative splicing in the regulation of contractile gene expression, achieved in part through modulating the activity of SRF, a key cardiac transcription factor.

  20. Dynamic regulation of β1 subunit trafficking controls vascular contractility

    Science.gov (United States)

    Leo, M. Dennis; Bannister, John P.; Narayanan, Damodaran; Nair, Anitha; Grubbs, Jordan E.; Gabrick, Kyle S.; Boop, Frederick A.; Jaggar, Jonathan H.

    2014-01-01

    Ion channels composed of pore-forming and auxiliary subunits control physiological functions in virtually all cell types. A conventional view is that channels assemble with their auxiliary subunits before anterograde plasma membrane trafficking of the protein complex. Whether the multisubunit composition of surface channels is fixed following protein synthesis or flexible and open to acute and, potentially, rapid modulation to control activity and cellular excitability is unclear. Arterial smooth muscle cells (myocytes) express large-conductance Ca2+-activated potassium (BK) channel α and auxiliary β1 subunits that are functionally significant modulators of arterial contractility. Here, we show that native BKα subunits are primarily (∼95%) plasma membrane-localized in human and rat arterial myocytes. In contrast, only a small fraction (∼10%) of total β1 subunits are located at the cell surface. Immunofluorescence resonance energy transfer microscopy demonstrated that intracellular β1 subunits are stored within Rab11A-postive recycling endosomes. Nitric oxide (NO), acting via cGMP-dependent protein kinase, and cAMP-dependent pathways stimulated rapid (≤1 min) anterograde trafficking of β1 subunit-containing recycling endosomes, which increased surface β1 almost threefold. These β1 subunits associated with surface-resident BKα proteins, elevating channel Ca2+ sensitivity and activity. Our data also show that rapid β1 subunit anterograde trafficking is the primary mechanism by which NO activates myocyte BK channels and induces vasodilation. In summary, we show that rapid β1 subunit surface trafficking controls functional BK channel activity in arterial myocytes and vascular contractility. Conceivably, regulated auxiliary subunit trafficking may control ion channel activity in a wide variety of cell types. PMID:24464482

  1. Clinical relevance of fascial tissue and dysfunctions.

    Science.gov (United States)

    Klingler, W; Velders, M; Hoppe, K; Pedro, M; Schleip, R

    2014-01-01

    Fascia is composed of collagenous connective tissue surrounding and interpenetrating skeletal muscle, joints, organs, nerves, and vascular beds. Fascial tissue forms a whole-body, continuous three-dimensional viscoelastic matrix of structural support. The classical concept of its mere passive role in force transmission has recently been disproven. Fascial tissue contains contractile elements enabling a modulating role in force generation and also mechanosensory fine-tuning. This hypothesis is supported by in vitro studies demonstrating an autonomous contraction of human lumbar fascia and a pharmacological induction of temporary contraction in rat fascial tissue. The ability of spontaneous regulation of fascial stiffness over a time period ranging from minutes to hours contributes more actively to musculoskeletal dynamics. Imbalance of this regulatory mechanism results in increased or decreased myofascial tonus, or diminished neuromuscular coordination, which are key contributors to the pathomechanisms of several musculoskeletal pathologies and pain syndromes. Here, we summarize anatomical and biomechanical properties of fascial tissue with a special focus on fascial dysfunctions and resulting clinical manifestations. Finally, we discuss current and future potential treatment options that can influence clinical manifestations of pain syndromes associated with fascial tissues.

  2. Repeated exposure to heat stress results in a diaphragm phenotype that resists ventilator-induced diaphragm dysfunction.

    Science.gov (United States)

    Yoshihara, Toshinori; Ichinoseki-Sekine, Noriko; Kakigi, Ryo; Tsuzuki, Takamasa; Sugiura, Takao; Powers, Scott K; Naito, Hisashi

    2015-11-01

    Controlled mechanical ventilation (CMV) is a life-saving intervention for patients in respiratory failure. Unfortunately, prolonged mechanical ventilation (MV) results in diaphragmatic atrophy and contractile dysfunction, both of which are predicted to contribute to problems in weaning patients from the ventilator. Therefore, developing a strategy to protect the diaphragm against ventilator-induced weakness is important. We tested the hypothesis that repeated bouts of heat stress result in diaphragm resistance against CMV-induced atrophy and contractile dysfunction. Male Wistar rats were randomly divided into six experimental groups: 1) control; 2) single bout of whole body heat stress; 3) repeated bouts of whole body heat stress; 4) 12 h CMV; 5) single bout of whole body heat stress 24 h before CMV; and 6) repeated bouts of whole body heat stress 1, 3, and 5 days before 12 h of CMV. Our results revealed that repeated bouts of heat stress resulted in increased levels of heat shock protein 72 in the diaphragm and protection against both CMV-induced diaphragmatic atrophy and contractile dysfunction at submaximal stimulation frequencies. The specific mechanisms responsible for this protection remain unclear: this heat stress-induced protection against CMV-induced diaphragmatic atrophy and weakness may be partially due to reduced diaphragmatic oxidative stress, diminished activation of signal transducer/transcriptional activator-3, lower caspase-3 activation, and decreased autophagy in the diaphragm.

  3. Voiding dysfunction - A review

    Directory of Open Access Journals (Sweden)

    Sripathi V

    2005-01-01

    Full Text Available In a child who is toilet trained the sudden onset of daytime wetting with frequency or urgency is alarming to the parents. Initially this subject was subdivided into a number of descriptive clinical conditions which led to a lot of confusion in recognition and management. Subsequently, the term elimination dysfunction was coined by Stephen Koff to emphasise the association between recurrent urinary infection, wetting, constipation and bladder overactivity. From a urodynamic point of view, in voiding dysfunction, there is either detrusor overactivity during bladder filling or dyssynergic action between the detrusor and the external sphincter during voiding. Identifying a given condition as a ′filling phase dysfunction′ or ′voiding phase dysfunction′ helps to provide appropriate therapy. Objective clinical criteria should be used to define voiding dysfunction. These include bladder wall thickening, large capacity bladder and infrequent voiding, bladder trabeculation and spinning top deformity of the urethra and a clinically demonstrated Vincent′s curtsy. The recognition and treatment of constipation is central to the adequate treatment of voiding dysfunction. Transcutaneous electric nerve stimuation for the treatment of detrusor overactivity, biofeedback with uroflow EMG to correct dyssynergic voiding, and behavioral therapy all serve to correct voiding dysfunction in its early stages. In established neurogenic bladder disease the use of Botulinum Toxin A injections into the detrusor or the external sphincter may help in restoring continence especially in those refractory to drug therapy. However in those children in whom the upper tracts are threatened, augmentation of the bladder may still be needed.

  4. Pharmacological activation of small conductance calcium-activated potassium channels with naphtho[1,2-d]thiazol-2-ylamine decreases guinea pig detrusor smooth muscle excitability and contractility.

    Science.gov (United States)

    Parajuli, Shankar P; Soder, Rupal P; Hristov, Kiril L; Petkov, Georgi V

    2012-01-01

    Small conductance Ca²⁺-activated K⁺ (SK) and intermediate conductance Ca(2+)-activated K⁺ (IK) channels are thought to be involved in detrusor smooth muscle (DSM) excitability and contractility. Using naphtho[1,2-d]thiazol-2-ylamine (SKA-31), a novel and highly specific SK/IK channel activator, we investigated whether pharmacological activation of SK/IK channels reduced guinea pig DSM excitability and contractility. We detected the expression of all known isoforms of SK (SK1-SK3) and IK channels at mRNA and protein levels in DSM by single-cell reverse transcription-polymerase chain reaction and Western blot. Using the perforated patch-clamp technique on freshly isolated DSM cells, we observed that SKA-31 (10 μM) increased SK currents, which were blocked by apamin (1 μM), a selective SK channel inhibitor. In current-clamp mode, SKA-31 (10 μM) hyperpolarized the cell resting membrane potential, which was blocked by apamin (1 μM) but not by 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34) (1 μM), a selective IK channel inhibitor. SKA-31 (10 nM-10 μM) significantly inhibited the spontaneous phasic contraction amplitude, frequency, duration, and muscle force in DSM isolated strips. The SKA-31 inhibitory effects on DSM contractility were blocked by apamin (1 μM) but not by TRAM-34 (1 μM), which did not per se significantly affect DSM spontaneous contractility. SK channel activation with SKA-31 reduced contractions evoked by electrical field stimulation. SKA-31 effects were reversible upon washout. In conclusion, SK channels, but not IK channels, mediate SKA-31 effects in guinea pig DSM. Pharmacological activation of SK channels reduces DSM excitability and contractility and therefore may provide a novel therapeutic approach for controlling bladder dysfunction.

  5. Impairment of endothelial-myocardial interaction increases the susceptibility of cardiomyocytes to ischemia/reperfusion injury.

    Directory of Open Access Journals (Sweden)

    Thorsten M Leucker

    Full Text Available Endothelial-myocardial interactions may be critically important for ischemia/reperfusion injury. Tetrahydrobiopterin (BH4 is a required cofactor for nitric oxide (NO production by endothelial NO synthase (eNOS. Hyperglycemia (HG leads to significant increases in oxidative stress, oxidizing BH4 to enzymatically incompetent dihydrobiopterin. How alterations in endothelial BH4 content impact myocardial ischemia/reperfusion injury remains elusive. The aim of this study was to examine the effect of endothelial-myocardial interaction on ischemia/reperfusion injury, with an emphasis on the role of endothelial BH4 content. Langendorff-perfused mouse hearts were treated by triton X-100 to produce endothelial dysfunction and subsequently subjected to 30 min of ischemia followed by 2 h of reperfusion. The recovery of left ventricular systolic and diastolic function during reperfusion was impaired in triton X-100 treated hearts compared with vehicle-treated hearts. Cardiomyocytes (CMs were co-cultured with endothelial cells (ECs and subsequently subjected to 2 h of hypoxia followed by 2 h of reoxygenation. Addition of ECs to CMs at a ratio of 1∶3 significantly increased NO production and decreased lactate dehydrogenase activity compared with CMs alone. This EC-derived protection was abolished by HG. The addition of 100 µM sepiapterin (a BH4 precursor or overexpression of GTP cyclohydrolase 1 (the rate-limiting enzyme for BH4 biosynthesis in ECs by gene trasfer enhanced endothelial BH4 levels, the ratio of eNOS dimer/monomer, eNOS phosphorylation, and NO production and decreased lactate dehydrogenase activity in the presence of HG. These results demonstrate that increased BH4 content in ECs by either pharmacological or genetic approaches reduces myocardial damage during hypoxia/reoxygenation in the presence of HG. Maintaining sufficient endothelial BH4 is crucial for cardioprotection against hypoxia/reoxygenation injury.

  6. Effects of extremely low frequency electromagnetic fields on intracellular calcium transients in cardiomyocytes.

    Science.gov (United States)

    Wei, Jinhong; Sun, Junqing; Xu, Hao; Shi, Liang; Sun, Lijun; Zhang, Jianbao

    2015-03-01

    Calcium transients play an essential role in cardiomyocytes and electromagnetic fields (EMF) and affect intracellular calcium levels in many types of cells. Effects of EMF on intracellular calcium transients in cardiomyocytes are not well studied. The aim of this study was to assess whether extremely low frequency electromagnetic fields (ELF-EMF) could affect intracellular calcium transients in cardiomyocytes. Cardiomyocytes isolated from neonatal Sprague-Dawley rats were exposed to rectangular-wave pulsed ELF-EMF at four different frequencies (15 Hz, 50 Hz, 75 Hz and 100 Hz) and at a flux density of 2 mT. Intracellular calcium concentration ([Ca(2+)]i) was measured using Fura-2/AM and spectrofluorometry. Perfusion of cardiomyocytes with a high concentration of caffeine (10 mM) was carried out to verify the function of the cardiac Na(+)/Ca(2+) exchanger (NCX) and the activity of sarco(endo)-plasmic reticulum Ca(2+)-ATPase (SERCA2a). The results showed that ELF-EMF enhanced the activities of NCX and SERCA2a, increased [Ca(2+)]i baseline level and frequency of calcium transients in cardiomyocytes and decreased the amplitude of calcium transients and calcium level in sarcoplasmic reticulum. These results indicated that ELF-EMF can regulate calcium-associated activities in cardiomyocytes. PMID:24499289

  7. Cardiomyocyte proliferation in cardiac development and regeneration: a guide to methodologies and interpretations.

    Science.gov (United States)

    Leone, Marina; Magadum, Ajit; Engel, Felix B

    2015-10-01

    The newt and the zebrafish have the ability to regenerate many of their tissues and organs including the heart. Thus, a major goal in experimental medicine is to elucidate the molecular mechanisms underlying the regenerative capacity of these species. A wide variety of experiments have demonstrated that naturally occurring heart regeneration relies on cardiomyocyte proliferation. Thus, major efforts have been invested to induce proliferation of mammalian cardiomyocytes in order to improve cardiac function after injury or to protect the heart from further functional deterioration. In this review, we describe and analyze methods currently used to evaluate cardiomyocyte proliferation. In addition, we summarize the literature on naturally occurring heart regeneration. Our analysis highlights that newt and zebrafish heart regeneration relies on factors that are also utilized in cardiomyocyte proliferation during mammalian fetal development. Most of these factors have, however, failed to induce adult mammalian cardiomyocyte proliferation. Finally, our analysis of mammalian neonatal heart regeneration indicates experiments that could resolve conflicting results in the literature, such as binucleation assays and clonal analysis. Collectively, cardiac regeneration based on cardiomyocyte proliferation is a promising approach for improving adult human cardiac function after injury, but it is important to elucidate the mechanisms arresting mammalian cardiomyocyte proliferation after birth and to utilize better assays to determine formation of new muscle mass.

  8. Multicolor mapping of the cardiomyocyte proliferation dynamics that construct the atrium.

    Science.gov (United States)

    Foglia, Matthew J; Cao, Jingli; Tornini, Valerie A; Poss, Kenneth D

    2016-05-15

    The orchestrated division of cardiomyocytes assembles heart chambers of distinct morphology. To understand the structural divergence of the cardiac chambers, we determined the contributions of individual embryonic cardiomyocytes to the atrium in zebrafish by multicolor fate-mapping and we compare our analysis to the established proliferation dynamics of ventricular cardiomyocytes. We find that most atrial cardiomyocytes become rod-shaped in the second week of life, generating a single-muscle-cell-thick myocardial wall with a striking webbed morphology. Inner pectinate myofibers form mainly by direct branching, unlike delamination events that create ventricular trabeculae. Thus, muscle clones assembling the atrial chamber can extend from wall to lumen. As zebrafish mature, atrial wall cardiomyocytes proliferate laterally to generate cohesive patches of diverse shapes and sizes, frequently with dominant clones that comprise 20-30% of the wall area. A subpopulation of cardiomyocytes that transiently express atrial myosin heavy chain (amhc) contributes substantially to specific regions of the ventricle, suggesting an unappreciated level of plasticity during chamber formation. Our findings reveal proliferation dynamics and fate decisions of cardiomyocytes that produce the distinct architecture of the atrium. PMID:26989176

  9. Cardiomyocyte proliferation in cardiac development and regeneration: a guide to methodologies and interpretations.

    Science.gov (United States)

    Leone, Marina; Magadum, Ajit; Engel, Felix B

    2015-10-01

    The newt and the zebrafish have the ability to regenerate many of their tissues and organs including the heart. Thus, a major goal in experimental medicine is to elucidate the molecular mechanisms underlying the regenerative capacity of these species. A wide variety of experiments have demonstrated that naturally occurring heart regeneration relies on cardiomyocyte proliferation. Thus, major efforts have been invested to induce proliferation of mammalian cardiomyocytes in order to improve cardiac function after injury or to protect the heart from further functional deterioration. In this review, we describe and analyze methods currently used to evaluate cardiomyocyte proliferation. In addition, we summarize the literature on naturally occurring heart regeneration. Our analysis highlights that newt and zebrafish heart regeneration relies on factors that are also utilized in cardiomyocyte proliferation during mammalian fetal development. Most of these factors have, however, failed to induce adult mammalian cardiomyocyte proliferation. Finally, our analysis of mammalian neonatal heart regeneration indicates experiments that could resolve conflicting results in the literature, such as binucleation assays and clonal analysis. Collectively, cardiac regeneration based on cardiomyocyte proliferation is a promising approach for improving adult human cardiac function after injury, but it is important to elucidate the mechanisms arresting mammalian cardiomyocyte proliferation after birth and to utilize better assays to determine formation of new muscle mass. PMID:26342071

  10. Biology of Sexual Dysfunction

    Directory of Open Access Journals (Sweden)

    Anil Kumar Mysore Nagaraj

    2009-05-01

    Full Text Available Sexual activity is a multifaceted activity, involving complex interactions between the nervous system, the endocrine system, the vascular system and a variety of structures that are instrumental in sexual excitement, intercourse and satisfaction. Sexual function has three components i.e., desire, arousal and orgasm. Many sexual dysfunctions can be categorized according to the phase of sexual response that is affected. In actual clinical practice however, sexual desire, arousal and orgasmic difficulties more often than not coexist, suggesting an integration of phases. Sexual dysfunction can result from a wide variety of psychological and physiological causes including derangements in the levels of sex hormones and neurotrensmitters. This review deals with the biology of different phases of sexual function as well as implications of hormones and neurotransmitters in sexual dysfunction

  11. CstF-64 is necessary for endoderm differentiation resulting in cardiomyocyte defects

    Directory of Open Access Journals (Sweden)

    Bradford A. Youngblood

    2014-11-01

    Full Text Available Although adult cardiomyocytes have the capacity for cellular regeneration, they are unable to fully repair severely injured hearts. The use of embryonic stem cell (ESC-derived cardiomyocytes as transplantable heart muscle cells has been proposed as a solution, but is limited by the lack of understanding of the developmental pathways leading to specification of cardiac progenitors. Identification of these pathways will enhance the ability to differentiate cardiomyocytes into a clinical source of transplantable cells. Here, we show that the mRNA 3′ end processing protein, CstF-64, is essential for cardiomyocyte differentiation in mouse ESCs. Loss of CstF-64 in mouse ESCs results in loss of differentiation potential toward the endodermal lineage. However, CstF-64 knockout (Cstf2E6 cells were able to differentiate into neuronal progenitors, demonstrating that some differentiation pathways were still intact. Markers for mesodermal differentiation were also present, although Cstf2E6 cells were defective in forming beating cardiomyocytes and expressing cardiac specific markers. Since the extraembryonic endoderm is needed for cardiomyocyte differentiation and endodermal markers were decreased, we hypothesized that endodermal factors were required for efficient cardiomyocyte formation in the Cstf2E6 cells. Using conditioned medium from the extraembryonic endodermal (XEN stem cell line we were able to restore cardiomyocyte differentiation in Cstf2E6 cells, suggesting that CstF-64 has a role in regulating endoderm differentiation that is necessary for cardiac specification and that extraembryonic endoderm signaling is essential for cardiomyocyte development.

  12. Growth factor PDGF-BB stimulates cultured cardiomyocytes to synthesize the extracellular matrix component hyaluronan.

    Directory of Open Access Journals (Sweden)

    Urban Hellman

    Full Text Available BACKGROUND: Hyaluronan (HA is a glycosaminoglycan located in the interstitial space which is essential for both structural and cell regulatory functions in connective tissue. We have previously shown that HA synthesis is up-regulated in a rat model of experimental cardiac hypertrophy and that cardiac tissue utilizes two different HA synthases in the hypertrophic process. Cardiomyocytes and fibroblasts are two major cell types in heart tissue. The fibroblasts are known to produce HA, but it has been unclear if cardiomyocytes share the same feature, and whether or not the different HA synthases are activated in the different cell types. METHODOLOGY/PRINCIPAL FINDINGS: This study shows, for the first time that cardiomyocytes can produce HA. Cardiomyocytes (HL-1 and fibroblasts (NIH 3T3 were cultivated in absence or presence of the growth factors FGF2, PDGF-BB and TGFB2. HA concentration was quantified by ELISA, and the size of HA was estimated using dynamic light scattering. Cardiomyocytes synthesized HA but only when stimulated by PDGF-BB, whereas fibroblasts synthesized HA without addition of growth factors as well as when stimulated by any of the three growth factors. When fibroblasts were stimulated by the growth factors, reverse dose dependence was observed, where the highest dose induced the least amount of HA. With the exception of TGFB2, a trend of reverse dose dependence of HA size was also observed. CONCLUSIONS/SIGNIFICANCE: Co-cultivation of cardiomyocytes and fibroblasts (80%/20% increased HA concentration far more that can be explained by HA synthesis by the two cell types separately, revealing a crosstalk between cardiomyocytes and fibroblasts that induces HA synthesis. We conclude that dynamic changes of the myocardium, such as in cardiac hypertrophy, do not depend on the cardiomyocyte alone, but are achieved when both cardiomyocytes and fibroblasts are present.

  13. Transdermal Nicotine Application Attenuates Cardiac Dysfunction after Severe Thermal Injury

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    Leif Claassen

    2015-01-01

    Full Text Available Background. Severe burn trauma leads to an immediate and strong inflammatory response inciting cardiac dysfunction that is associated with high morbidity and mortality. The aim of this study was to determine whether transdermal application of nicotine could influence the burn-induced cardiac dysfunction via its known immunomodulatory effects. Material and Methods. A standardized rat burn model was used in 35 male Sprague Dawley rats. The experimental animals were divided into a control group, a burn trauma group, a burn trauma group with additional nicotine treatment, and a sham group with five experimental animals per group. The latter two groups received nicotine administration. Using microtip catheterization, functional parameters of the heart were assessed 12 or 24 hours after infliction of burn trauma. Results. Burn trauma led to significantly decreased blood pressure (BP values whereas nicotine administration normalized BP. As expected, burn trauma also induced a significant deterioration of myocardial contractility and relaxation parameters. After application of nicotine these adverse effects were attenuated. Conclusion. The present study showed that transdermal nicotine administration has normalizing effects on burn-induced myocardial dysfunction parameters. Further research is warranted to gain insight in molecular mechanisms and pathways and to evaluate potential treatment options in humans.

  14. Contractile responses to ergotamine and dihydroergotamine in the perfused middle cerebral artery of rat

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer; Nilsson, Elisabeth; Edvinsson, Lars

    2007-01-01

    mmHg and luminally perfused. All vessels used attained spontaneous contractile tone (34.9+/-1.8% of resting tone) and responded to luminal adenosine triphosphate (ATP) with dilatation (24.1+/-4.0%), which showed functioning endothelium. Luminally added ergotamine or DHE induced maximal contractions...... no significant effect. Using a myograph technique, isolated ring segments of the MCA with intact endothelium were mounted on two metal wires. Neither agonist caused relaxation of resting vessels, however, they both responded by weak contractile responses (26+/-3% of submaximal contractile capacity relative to 60...

  15. ERK/PP1a/PLB/SERCA2a and JNK pathways are involved in luteolin-mediated protection of rat hearts and cardiomyocytes following ischemia/reperfusion.

    Directory of Open Access Journals (Sweden)

    Xin Wu

    Full Text Available Luteolin has long been used in traditional Chinese medicine for treatment of various diseases. Recent studies have suggested that administration of luteolin yields cardioprotective effects during ischemia/reperfusion (I/R in rats. However, the precise mechanisms of this action remain unclear. The aim of this study is to confirm that luteolin-mediated extracellular signal regulated kinase (ERK1/2 and c-Jun N-terminal kinase (JNK pathways are responsible for their cardioprotective effects during I/R. Wistar rats were divided into the following groups: (i DMSO group (DMSO; (ii I/R group (I/R; (iii luteolin+I/R group (Lut+I/R; (iv ERK1/2 inhibitor PD98059+I/R group (PD+I/R; (v PD98059+luteolin+I/R group (PD+Lut+I/R; and (vi JNK inhibitor SP600125+I/R group (SP+I/R. The following properties were measured: contractile function of isolated heart and cardiomyocytes; infarct size; the release of lactate dehydrogenase (LDH; the percentage of apoptotic cells; the expression levels of Bcl-2 and Bax; and phosphorylation status of ERK1/2, JNK, type 1 protein phosphatase (PP1a, phospholamban (PLB and sarcoplasmic reticulum Ca(2+-ATPase (SERCA2a. Our data showed that pretreatment with luteolin or SP600125 significantly improved the contraction of the isolated heart and cardiomyocytes, reduced infarct size and LDH activity, decreased the rate of apoptosis and increased the Bcl-2/Bax ratio. However, pretreatment with PD98059 alone before I/R had no effect on the above indexes. Further, these consequences of luteolin pretreatment were abrogated by co-administration of PD98059. We also found that pretreatment with PD98059 caused a significant increase in JNK expression, and SP600125 could cause ERK1/2 activation during I/R. In addition, we are the first to demonstrate that luteolin affects PP1a expression, which results in the up-regulation of the PLB, thereby relieving its inhibition of SERCA2a. These results showed that luteolin improves cardiomyocyte contractile

  16. Mitochondrial Dysfunction in Cancer

    Directory of Open Access Journals (Sweden)

    Michelle L Boland

    2013-12-01

    Full Text Available A mechanistic understanding of how mitochondrial dysfunction contributes to cell growth and tumorigenesis is emerging beyond Warburg as an area of research that is under-explored in terms of its significance for clinical management of cancer. Work discussed in this review focuses less on the Warburg effect and more on mitochondria and how dysfunctional mitochondria modulate cell cycle, gene expression, metabolism, cell viability and other more conventional aspects of cell growth and stress responses. There is increasing evidence that key oncogenes and tumor suppressors modulate mitochondrial dynamics through important signaling pathways and that mitochondrial mass and function vary between tumors and individuals but the sigificance of these events for cancer are not fully appreciated. We explore the interplay between key molecules involved in mitochondrial fission and fusion and in apoptosis, as well as in mitophagy, biogenesis and spatial dynamics and consider how these distinct mechanisms are coordinated in response to physiological stresses such as hypoxia and nutrient deprivation. Importantly, we examine how deregulation of these processes in cancer has knockon effects for cell proliferation and growth. Scientifically, there is also scope for defining what mitochondria dysfunction is and here we address the extent to which the functional consequences of such dysfunction can be determined and exploited for cancer diagnosis and treatment.

  17. Shared Parenting Dysfunction.

    Science.gov (United States)

    Turkat, Ira Daniel

    2002-01-01

    Joint custody of children is the most prevalent court ordered arrangement for families of divorce. A growing body of literature indicates that many parents engage in behaviors that are incompatible with shared parenting. This article provides specific criteria for a definition of the Shared Parenting Dysfunction. Clinical aspects of the phenomenon…

  18. The location of energetic compartments affects energetic communication in cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Rikke eBirkedal

    2014-09-01

    Full Text Available The heart relies on accurate regulation of mitochondrial energy supply to match energy demand. The main regulators are Ca2+ and feedback of ADP and Pi. Regulation via feedback has intrigued for decades. First, the heart exhibits a remarkable metabolic stability. Second, diffusion of ADP and other molecules is restricted specifically in heart and red muscle, where a fast feedback is needed the most. To explain the regulation by feedback, compartmentalization must be taken into account. Experiments and theoretical approaches suggest that cardiomyocyte energetic compartmentalization is elaborate with barriers obstructing diffusion in the cytosol and at the level of the mitochondrial outer membrane (MOM. A recent study suggests the barriers are organized in a lattice with dimensions in agreement with those of intracellular structures. Here, we discuss the possible location of these barriers. The more plausible scenario includes a barrier at the level of MOM. Much research has focused on how the permeability of MOM itself is regulated, and the importance of the creatine kinase system to facilitate energetic communication. We hypothesize that at least part of the diffusion restriction at the MOM level is not by MOM itself, but due to the close physical association between the sarcoplasmic reticulum (SR and mitochondria. This will explain why animals with a disabled creatine kinase system exhibit rather mild phenotype modifications. Mitochondria are hubs of energetics, but also ROS production and signaling. The close association between SR and mitochondria may form a diffusion barrier to ADP added outside a permeabilised cardiomyocyte. But in vivo, it is the structural basis for the mitochondrial-SR coupling that is crucial for the regulation of mitochondrial Ca2+-transients to regulate energetics, and for avoiding Ca2+-overload and irreversible opening of the mitochondrial permeability transition pore.

  19. Importance of Thickness in Human Cardiomyocyte Network for Effective Electrophysiological Stimulation Using On-Chip Extracellular Microelectrodes

    Science.gov (United States)

    Hamada, Tomoyo; Nomura, Fumimasa; Kaneko, Tomoyuki; Yasuda, Kenji

    2012-06-01

    We have developed a three-dimensionally controlled in vitro human cardiomyocyte network assay for the measurements of drug-induced conductivity changes and the appearance of fatal arrhythmia such as ventricular tachycardia/fibrillation for more precise in vitro predictive cardiotoxicity. To construct an artificial conductance propagation model of a human cardiomyocyte network, first, we examined the cell concentration dependence of the cell network heights and found the existence of a height limit of cell networks, which was double-layer height, whereas the cardiomyocytes were effectively and homogeneously cultivated within the microchamber maintaining their spatial distribution constant and their electrophysiological conductance and propagation were successfully recorded using a microelectrode array set on the bottom of the microchamber. The pacing ability of a cardiomyocyte's electrophysiological response has been evaluated using microelectrode extracellular stimulation, and the stimulation for pacing also successfully regulated the beating frequencies of two-layered cardiomyocyte networks, whereas monolayered cardiomyocyte networks were hardly stimulated by the external electrodes using the two-layered cardiomyocyte stimulation condition. The stability of the lined-up shape of human cardiomyocytes within the rectangularly arranged agarose microchambers was limited for a two-layered cardiomyocyte network because their stronger force generation shrunk those cells after peeling off the substrate. The results indicate the importance of fabrication technology of thickness control of cellular networks for effective extracellular stimulation and the potential concerning thick cardiomyocyte networks for long-term cultivation.

  20. Cognitive dysfunction after cardiovascular surgery

    DEFF Research Database (Denmark)

    Funder, K S; Steinmetz, J; Rasmussen, L S

    2009-01-01

    This review describes the incidence, risk factors, and long-term consequences of cognitive dysfunction after cardiovascular surgery. Postoperative cognitive dysfunction (POCD) is increasingly being recognized as an important complication, especially in the elderly. A highly sensitive neuropsychol...

  1. Adipose-derived stem cells inhibit the contractile myofibroblast in Dupuytren's disease.

    NARCIS (Netherlands)

    Verhoekx, J.S.; Mudera, V.; Walbeehm, E.T.; Hovius, S.E.

    2013-01-01

    BACKGROUND: In an attempt to provide minimally invasive treatment for Dupuytren's disease, percutaneous disruption of the affected tissue followed by lipografting is being tested. Contractile myofibroblasts drive this fibroproliferative disorder, whereas stem cells have recently been implicated in p

  2. Mapping of redox state of mitochondrial cytochromes in live cardiomyocytes using Raman microspectroscopy

    DEFF Research Database (Denmark)

    Brazhe, Nadezda A; Treiman, Marek; Brazhe, Alexey R;

    2012-01-01

    This paper presents a nonivasive approach to study redox state of reduced cytochromes [Formula: see text], [Formula: see text] and [Formula: see text] of complexes II and III in mitochondria of live cardiomyocytes by means of Raman microspectroscopy. For the first time with the proposed approach we......-shaped cardiomyocytes possess uneven distribution of reduced cytochromes [Formula: see text], [Formula: see text] and [Formula: see text] in cell center and periphery. Moreover, by means of Raman spectroscopy we demonstrated the decrease in the relative amounts of reduced cytochromes [Formula: see text], [Formula: see...... perform studies of rod- and round-shaped cardiomyocytes, representing different morphological and functional states. Raman mapping and cluster analysis reveal that these cardiomyocytes differ in the amounts of reduced cytochromes [Formula: see text], [Formula: see text] and [Formula: see text]. The rod...

  3. Modeling Cardiovascular Diseases with Patient-Specific Human Pluripotent Stem Cell-Derived Cardiomyocytes

    Science.gov (United States)

    Burridge, Paul W.; Diecke, Sebastian; Matsa, Elena; Sharma, Arun; Wu, Haodi; Wu, Joseph C.

    2016-01-01

    The generation of cardiomyocytes from human induced pluripotent stem cells (hiPSCs) provides a source of cells that accurately recapitulate the human cardiac pathophysiology. The application of these cells allows for modeling of cardiovascular diseases, providing a novel understanding of human disease mechanisms and assessment of therapies. Here, we describe a stepwise protocol developed in our laboratory for the generation of hiPSCs from patients with a specific disease phenotype, long-term hiPSC culture and cryopreservation, differentiation of hiPSCs to cardiomyocytes, and assessment of disease phenotypes. Our protocol combines a number of innovative tools that include a codon-optimized mini intronic plasmid (CoMiP), chemically defined culture conditions to achieve high efficiencies of reprogramming and differentiation, and calcium imaging for assessment of cardiomyocyte phenotypes. Thus, this protocol provides a complete guide to use a patient cohort on a testable cardiomyocyte platform for pharmacological drug assessment. PMID:25690476

  4. Late Sodium Current in Human Atrial Cardiomyocytes from Patients in Sinus Rhythm and Atrial Fibrillation

    DEFF Research Database (Denmark)

    Poulet, Claire; Wettwer, Erich; Grunnet, Morten;

    2015-01-01

    Slowly inactivating Na+ channels conducting "late" Na+ current (INa,late) contribute to ventricular arrhythmogenesis under pathological conditions. INa,late was also reported to play a role in chronic atrial fibrillation (AF). The objective of this study was to investigate INa,late in human right......, and lower in AF than in SR. In conclusion, We confirm for the first time a TTX-sensitive current (INa,late) in right atrial cardiomyocytes from SR and AF patients at room temperature, but not at physiological temperature. While our study provides evidence for the presence of INa,late in human atria...... atrial cardiomyocytes as a putative drug target for treatment of AF. To activate Na+ channels, cardiomyocytes from transgenic mice which exhibit INa,late (ΔKPQ), and right atrial cardiomyocytes from patients in sinus rhythm (SR) and AF were voltage clamped at room temperature by 250-ms long test pulses...

  5. Motor-free actin bundle contractility driven by molecular crowding

    CERN Document Server

    Schnauß, Jörg; Schuldt, Carsten; Schmidt, B U Sebastian; Glaser, Martin; Strehle, Dan; Heussinger, Claus; Käs, Josef A

    2015-01-01

    Modeling approaches of suspended, rod-like particles and recent experimental data have shown that depletion forces display different signatures depending on the orientation of these particles. It has been shown that axial attraction of two rods yields contractile forces of 0.1pN that are independent of the relative axial shift of the two rods. Here, we measured depletion-caused interactions of actin bundles extending the phase space of single pairs of rods to a multi-particle system. In contrast to a filament pair, we found forces up to 3pN . Upon bundle relaxation forces decayed exponentially with a mean decay time of 3.4s . These different dynamics are explained within the frame of a mathematical model by taking pairwise interactions to a multi-filament scale. The macromolecular content employed for our experiments is well below the crowding of cells. Thus, we propose that arising forces can contribute to biological force generation without the need to convert chemical energy into mechanical work.

  6. Phospholemman deficiency in postinfarct hearts: enhanced contractility but increased mortality.

    Science.gov (United States)

    Mirza, M Ayoub; Lane, Susan; Yang, Zequan; Karaoli, Themis; Akosah, Kwame; Hossack, John; McDuffie, Marcia; Wang, JuFang; Zhang, Xue-Qian; Song, Jianliang; Cheung, Joseph Y; Tucker, Amy L

    2012-06-01

    Phospholemman (PLM) regulates [Na(+) ](i), [Ca(2+)](i) and contractility through its interactions with Na(+)-K(+)-ATPase (NKA) and Na(+) /Ca(2+) exchanger (NCX1) in the heart. Both expression and phosphorylation of PLM are altered after myocardial infarction (MI) and heart failure. We tested the hypothesis that absence of PLM regulation of NKA and NCX1 in PLM-knockout (KO) mice is detrimental. Three weeks after MI, wild-type (WT) and PLM-KO hearts were similarly hypertrophied. PLM expression was lower but fractional phosphorylation was higher in WT-MI compared to WT-sham hearts. Left ventricular ejection fraction was severely depressed in WT-MI but significantly less depressed in PLM-KO-MI hearts despite similar infarct sizes. Compared with WT-sham myocytes, the abnormal [Ca(2+) ], transient and contraction amplitudes observed in WT-MI myocytes were ameliorated by genetic absence of PLM. In addition, NCX1 current was depressed in WT-MI but not in PLM-KO-MI myocytes. Despite improved myocardial and myocyte performance, PLM-KO mice demonstrated reduced survival after MI. Our findings indicate that alterations in PLM expression and phosphorylation are important adaptations post-MI, and that complete absence of PLM regulation of NKA and NCX1 is detrimental in post-MI animals.

  7. Contractile Force of Human Extraocular Muscle: A Theoretical Analysis

    Science.gov (United States)

    Guo, Hongmei; Gao, Zhipeng; Chen, Weiyi

    2016-01-01

    Aim. The length-contractile force relationships of six human extraocular muscles (EOMs) in primary innervations should be determined during eye movement modeling and surgery of clinical EOMs. This study aims to investigate these relationships. Method. The proposal is based on the assumption that six EOMs have similar constitutive relationships, with the eye suspended in the primary position. The constitutive relationships of EOMs are obtained by optimizing from previous experimental data and the theory of mechanical equilibrium using traditional model. Further, simulate the existing experiment of resistance force, and then compare the simulated results with the existing experimental results. Finally, the mechanical constitutive relationships of EOMs are obtained. Results. The results show that the simulated resistance forces from the other four EOMs except for the horizontal recti well agree with previous experimental results. Conclusion. The mechanical constitutive relationships of six EOMs in primary innervations are obtained, and the rationality of the constitutive relationships is verified. Whereafter, the active stress-strain relationships of the six EOMs in the primary innervations are obtained. The research results can improve the eye movement model to predict the surgical amounts of EOMs before EOM surgery more precisely. PMID:27087774

  8. Considerations for Contractile Electroactive Polymeric Materials and Actuators

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Lenore; Erickson, Carl J.; Meixler, Lewis D.; Ascione, George; Gentile, Charles A.; Tilson, Charles; Bernasek, Stephen L.; Abelev, Esta

    2009-06-16

    Ras Labs produces electroactive polymer (EAP) based materials and actuators that bend, swell, ripple and now contract (new development) with low electric input. This is an important attribute because of the ability of contraction to produce life-like motion. The mechanism of contraction is not well understood. Radionuclide-labeled experiments were conducted to follow the movement of electrolytes and water in these EAPs when activated. Extreme temperature experiments were performed on the contractile EAPs with very favorable results. One of the biggest challenges in developing these actuators, however, is the electrode-EAP interface because of the pronounced movement of the EAP. Plasma treatments of metallic electrodes were investigated in order to improve the attachment of the embedded electrodes to the EAP material. Surface analysis, adhesive testing, and mechanical testing were conducted to test metal surfaces and metal-polymer interfaces. The nitrogen plasma treatment of titanium produced a strong metal-polymer interface; however, oxygen plasma treatment of both stainless steel and titanium produced even stronger metal-polymer interfaces. Plasma treatment of the electrodes allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface.

  9. Considerations for Contractile Electroactive Polymeric Materials and Actuators

    International Nuclear Information System (INIS)

    Ras Labs produces electroactive polymer (EAP) based materials and actuators that bend, swell, ripple and now contract (new development) with low electric input. This is an important attribute because of the ability of contraction to produce life-like motion. The mechanism of contraction is not well understood. Radionuclide-labeled experiments were conducted to follow the movement of electrolytes and water in these EAPs when activated. Extreme temperature experiments were performed on the contractile EAPs with very favorable results. One of the biggest challenges in developing these actuators, however, is the electrode-EAP interface because of the pronounced movement of the EAP. Plasma treatments of metallic electrodes were investigated in order to improve the attachment of the embedded electrodes to the EAP material. Surface analysis, adhesive testing, and mechanical testing were conducted to test metal surfaces and metal-polymer interfaces. The nitrogen plasma treatment of titanium produced a strong metal-polymer interface; however, oxygen plasma treatment of both stainless steel and titanium produced even stronger metal-polymer interfaces. Plasma treatment of the electrodes allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface

  10. Antioxidant catalase rescues against high fat diet-induced cardiac dysfunction via an IKKβ-AMPK-dependent regulation of autophagy.

    Science.gov (United States)

    Liang, Lei; Shou, Xi-Ling; Zhao, Hai-Kang; Ren, Gu-Qun; Wang, Jian-Bang; Wang, Xi-Hui; Ai, Wen-Ting; Maris, Jackie R; Hueckstaedt, Lindsay K; Ma, Ai-Qun; Zhang, Yingmei

    2015-02-01

    Autophagy, a conservative degradation process for long-lived and damaged proteins, participates in a variety of biological processes including obesity. However, the precise mechanism of action behind obesity-induced changes in autophagy still remains elusive. This study was designed to examine the role of the antioxidant catalase in high fat diet-induced changes in cardiac geometry and function as well as the underlying mechanism of action involved with a focus on autophagy. Wild-type (WT) and transgenic mice with cardiac overexpression of catalase were fed low or high fat diet for 20 weeks prior to assessment of myocardial geometry and function. High fat diet intake triggered obesity, hyperinsulinemia, and hypertriglyceridemia, the effects of which were unaffected by catalase transgene. Myocardial geometry and function were compromised with fat diet intake as manifested by cardiac hypertrophy, enlarged left ventricular end systolic and diastolic diameters, fractional shortening, cardiomyocyte contractile capacity and intracellular Ca²⁺ mishandling, the effects of which were ameliorated by catalase. High fat diet intake promoted reactive oxygen species production and suppressed autophagy in the heart, the effects of which were attenuated by catalase. High fat diet intake dampened phosphorylation of inhibitor kappa B kinase β(IKKβ), AMP-activated protein kinase (AMPK) and tuberous sclerosis 2 (TSC2) while promoting phosphorylation of mTOR, the effects of which were ablated by catalase. In vitro study revealed that palmitic acid compromised cardiomyocyte autophagy and contractile function in a manner reminiscent of fat diet intake, the effect of which was significantly alleviated by inhibition of IKKβ, activation of AMPK and induction of autophagy. Taken together, our data revealed that the antioxidant catalase counteracts against high fat diet-induced cardiac geometric and functional anomalies possibly via an IKKβ-AMPK-dependent restoration of myocardial

  11. A comparative study of contractility of the heart ventricle in some ectothermic vertebrates

    OpenAIRE

    Sergey Kharin; Dmitry Shmakov

    2009-01-01

    The purpose of this study was to analyze contractility of the heart ventricle in selected reptilian and amphibian species having the same ventricular excitation pattern. Systolic time intervals and indices of contractility of the heart ventricle were measured in anaesthetized frogs, snakes, and tortoises by use of polycardiography. The electromechanical delay was significantly shorter in tortoises compared with the other two species. The isovolumetric contraction time in frogs was approximate...

  12. Leptin as a mediator between obesity and cardiac dysfunction

    Directory of Open Access Journals (Sweden)

    Joanna Karbowska

    2012-05-01

    Full Text Available  Obesity is now recognised as one of the most important risk factors for heart disease. Obese individuals have high circulating levels of leptin, a hormone secreted by adipose tissue and in­volved in energy homeostasis. Growing evidence suggests that leptin may contribute to the development of cardiac dysfunction. In a large prospective study leptin has been shown to be an independent risk factor for coronary heart disease. An independent positive association has also been found between plasma leptin levels and heart rate in hypertensive patients and heart transplant recipients. In animal studies chronic leptin infusion increased heart rate and blood pressure. It has also been demonstrated that circulating leptin levels are elevated in patients with heart failure. The level of plasma leptin was associated with increased myocardial wall thickness and correlated with left ventricular mass, suggesting a role for this hormone in mediating left ventricular hypertrophy in humans. Moreover, leptin directly induced hypertrophy and hyperplasia in human and rodent cardiomyocytes, accompanied by cardiac extracellular matrix remodelling. Leptin may also influence energy substrate utilisation in cardiac tissue.These findings suggest that leptin acting directly or through the sympathetic nervous system may have adverse effects on cardiac structure and function, and that chronic hyperleptinaemia may greatly increase the risk of cardiac disorders. Additional studies are needed to define the role of leptin in cardiac physiology and pathophysiology, nevertheless the reduction in plasma leptin levels with caloric restriction and weight loss may prevent cardiac dysfunction in obese patients.

  13. Stretch-induced hypertrophy activates NFkB-mediated VEGF secretion in adult cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Anna Leychenko

    Full Text Available Hypertension and myocardial infarction are associated with the onset of hypertrophy. Hypertrophy is a compensatory response mechanism to increases in mechanical load due to pressure or volume overload. It is characterized by extracellular matrix remodeling and hypertrophic growth of adult cardiomyocytes. Production of Vascular Endothelial Growth Factor (VEGF, which acts as an angiogenic factor and a modulator of cardiomyocyte function, is regulated by mechanical stretch. Mechanical stretch promotes VEGF secretion in neonatal cardiomyocytes. Whether this effect is retained in adult cells and the molecular mechanism mediating stretch-induced VEGF secretion has not been elucidated. Our objective was to investigate whether cyclic mechanical stretch induces VEGF secretion in adult cardiomyocytes and to identify the molecular mechanism mediating VEGF secretion in these cells. Isolated primary adult rat cardiomyocytes (ARCMs were subjected to cyclic mechanical stretch at an extension level of 10% at 30 cycles/min that induces hypertrophic responses. Cyclic mechanical stretch induced a 3-fold increase in VEGF secretion in ARCMs compared to non-stretch controls. This increase in stretch-induced VEGF secretion correlated with NFkB activation. Cyclic mechanical stretch-mediated VEGF secretion was blocked by an NFkB peptide inhibitor and expression of a dominant negative mutant IkBα, but not by inhibitors of the MAPK/ERK1/2 or PI3K pathways. Chromatin immunoprecipitation assays demonstrated an interaction of NFkB with the VEGF promoter in stretched primary cardiomyocytes. Moreover, VEGF secretion is increased in the stretched myocardium during pressure overload-induced hypertrophy. These findings are the first to demonstrate that NFkB activation plays a role in mediating VEGF secretion upon cyclic mechanical stretch in adult cardiomyocytes. Signaling by NFkB initiated in response to cyclic mechanical stretch may therefore coordinate the hypertrophic

  14. Mitochondrial dynamics in the adult cardiomyocytes: which roles for a highly specialized cell?

    OpenAIRE

    FredericJOUBERT; MartaNovotova

    2013-01-01

    Mitochondrial dynamics is a recent topic of research in the field of cardiac physiology. The study of mechanisms involved in the morphological changes and in the mobility of mitochondria is legitimate since the adult cardiomyocytes possess numerous mitochondria which occupy at least 30% of cell volume. However, architectural constraints exist in the cardiomyocyte that limit mitochondrial movements and communication between adjacent mitochondria. Still, the proteins involved in mitochondrial f...

  15. High Uric Acid Induces Insulin Resistance in Cardiomyocytes In Vitro and In Vivo.

    Directory of Open Access Journals (Sweden)

    Li Zhi

    Full Text Available Clinical studies have shown hyperuricemia strongly associated with insulin resistance as well as cardiovascular disease. Direct evidence of how high uric acid (HUA affects insulin resistance in cardiomyocytes, but the pathological mechanism of HUA associated with cardiovascular disease remains to be clarified. We aimed to examine the effect of HUA on insulin sensitivity in cardiomyocytes and on insulin resistance in hyperuricemic mouse model. We exposed primary cardiomyocytes and a rat cardiomyocyte cell line, H9c2 cardiomyocytes, to HUA, then quantified glucose uptake with a fluorescent glucose analog, 2-NBDG, after insulin challenge and detected reactive oxygen species (ROS production. Western blot analysis was used to examine the levels of insulin receptor (IR, phosphorylated insulin receptor substrate 1 (IRS1, Ser307 and phospho-Akt (Ser473. We monitored the impact of HUA on insulin resistance, insulin signaling and IR, phospho-IRS1 (Ser307 and phospho-Akt levels in myocardial tissue of an acute hyperuricemia mouse model established by potassium oxonate treatment. HUA inhibited insulin-induced glucose uptake in H9c2 and primary cardiomyocytes. It increased ROS production; pretreatment with N-acetyl-L-cysteine (NAC, a ROS scavenger, reversed HUA-inhibited glucose uptake induced by insulin. HUA exposure directly increased the phospho-IRS1 (Ser307 response to insulin and inhibited that of phospho-Akt in H9C2 cardiomyocytes, which was blocked by NAC. Furthermore, the acute hyperuricemic mice model showed impaired glucose tolerance and insulin tolerance accompanied by increased phospho-IRS1 (Ser307 and inhibited phospho-Akt response to insulin in myocardial tissues. HUA inhibited insulin signaling and induced insulin resistance in cardiomyocytes in vitro and in vivo, which is a novel potential mechanism of hyperuricemic-related cardiovascular disease.

  16. Muscle-on-chip: An in vitro model for donor–host cardiomyocyte coupling

    Science.gov (United States)

    Dierickx, Pieterjan

    2016-01-01

    A key aspect of cardiac cell–based therapy is the proper integration of newly formed cardiomyocytes into the remnant myocardium after injury. In this issue, Aratyn-Schaus et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201508026) describe an in vitro model for heterogeneous cardiomyocyte coupling in which force transmission between cells can be measured. PMID:26858264

  17. Genetics Home Reference: surfactant dysfunction

    Science.gov (United States)

    ... and decreased surfactant function. The loss of functional surfactant raises surface tension in the alveoli, causing severe breathing problems. The combination of SP-B and SP-C dysfunction may explain why the signs and symptoms of SP-B deficiency ... dysfunction sometimes called SP-C dysfunction. These mutations ...

  18. A comparative study of contractility of the heart ventricle in some ectothermic vertebrates

    Directory of Open Access Journals (Sweden)

    Sergey Kharin

    2009-07-01

    Full Text Available The purpose of this study was to analyze contractility of the heart ventricle in selected reptilian and amphibian species having the same ventricular excitation pattern. Systolic time intervals and indices of contractility of the heart ventricle were measured in anaesthetized frogs, snakes, and tortoises by use of polycardiography. The electromechanical delay was significantly shorter in tortoises compared with the other two species. The isovolumetric contraction time in frogs was approximately twofold longer than in reptiles. The pre-ejection period was the longest in frogs and the shortest in tortoises, whereas snakes were intermediate. The ejection time was slightly longer in tortoises compared with the other two species. The greatest isovolumetric contraction index and the smallest myocardial tension index corresponded to the frog and tortoise heart ventricle, respectively. The intrasystolic index in tortoises was significantly greater than in frogs, whereas quite similar to that in snakes. The frog ventricle had lower contractility compared with the reptilian one. Although ventricular contractility tended to be lower in snakes compared with tortoises, this difference was not statistically significant. Possible causes for these differences are discussed. We suppose a large variety in ventricular contractility among amphibian and reptilian species having the same ventricular activation pattern. This variety may be conditioned by heart anatomy, intracardiac shunting, lifestyles, and habitats. It can only be hypothesized that on the average, ventricular contractility is higher in reptiles compared with amphibians and in chelonians compared with snakes.

  19. Reliability of contractile properties of the knee extensor muscles in individuals with post-polio syndrome.

    Directory of Open Access Journals (Sweden)

    Eric L Voorn

    Full Text Available To assess the reliability of contractile properties of the knee extensor muscles in 23 individuals with post-polio syndrome (PPS and 18 age-matched healthy individuals.Contractile properties of the knee extensors were assessed from repeated electrically evoked contractions on 2 separate days, with the use of a fixed dynamometer. Reliability was determined for fatigue resistance, rate of torque development (MRTD, and early and late relaxation time (RT50 and RT25, using the intraclass correlation coefficient (ICC and standard error of measurement (SEM, expressed as % of the mean.In both groups, reliability for fatigue resistance was good, with high ICCs (>0.90 and small SEM values (PPS: 7.1%, healthy individuals: 7.0%. Reliability for contractile speed indices varied, with the best values found for RT50 (ICCs>0.82, SEM values <2.8%. We found no systematic differences between test and retest occasions, except for RT50 in healthy subjects (p = 0.016.In PPS and healthy individuals, the reliability of fatigue resistance, as obtained from electrically evoked contractions is high. The reliability of contractile speed is only moderate, except for RT50 in PPS, demonstrating high reliability.This was the first study to examine the reliability of electrically evoked contractile properties in individuals with PPS. Our results demonstrate its potential to study mechanisms underlying muscle fatigue in PPS and to evaluate changes in contractile properties over time in response to interventions or from natural course.

  20. Antioxidant Effect of Selenium-containing Glutathione S-Transferase in Rat Cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    YIN Li; HAN Xiao; YU Yang; GUO Xiao; REN Li-qun; FANG Jing-qi; LIU Zhi-yi; YAN Gang-lin; WEI Jing-yan

    2012-01-01

    As one of the most important antioxidant enzymes,glutathione peroxidase(GPX) protects cells and tissues from oxidative damage,and plays an important role in cardiovascular and cerebrovascular injuries induced by oxidative stress.The antioxidant effect of selenium-containing glutathione S-transferase(Se-GST),a mimic of GPX was investigated on rat cardiomyocytes.To explore the protection function of Se-GST in hydrogen peroxide(H2O2) challenged rat cardiomyocytes,we examined malondialdehyde(MDA),lactate dehydrogenase(LDH),superoxide dismutase(SOD) and cell apoptosis.The results demonstrate exposure of rat cardiomyocytes to H2O2 for 6 and 12 h induced the significant increases of MDA,LDH and apoptosis rate of cardiomyocytes,but pretreatment of rat cardiomyocytes with Se-GST at 0.0005 or 0.001 unit/mL prevents oxidative stress induced by H2O2 with the decreases of cell apoptosis.All the results him Se-GST has antioxidant activity for oxidative stress challenged rat cardiomyocytes.

  1. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections

    Science.gov (United States)

    Bensley, Jonathan Guy; de Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-04-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4‧,6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2-10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections.

  2. Cardiomyocytes display low mitochondrial priming and are highly resistant toward cytotoxic T‐cell killing

    Science.gov (United States)

    Zheng, Xiang; Halle, Stephan; Yu, Kai; Mishra, Pooja; Scherr, Michaela; Pietzsch, Stefan; Willenzon, Stefanie; Janssen, Anika; Boelter, Jasmin; Hilfiker‐Kleiner, Denise; Eder, Matthias

    2016-01-01

    Following heart transplantation, alloimmune responses can cause graft rejection by damaging donor vascular and parenchymal cells. However, it remains unclear whether cardiomyocytes are also directly killed by immune cells. Here, we used two‐photon microscopy to investigate how graft‐specific effector CD8+ T cells interact with cardiomyocytes in a mouse heart transplantation model. Surprisingly, we observed that CD8+ T cells are completely impaired in killing cardiomyocytes. Even after virus‐mediated preactivation, antigen‐specific CD8+ T cells largely fail to lyse these cells although both cell types engage in dynamic interactions. Furthermore, we established a two‐photon microscopy‐based assay using intact myocardium to determine the susceptibility of cardiomyocytes to undergo apoptosis. This feature, also known as mitochondrial priming reveals an unexpected weak predisposition of cardiomyocytes to undergo apoptosis in situ. These observations together with the early exhaustion phenotype of graft‐infiltrating specific T cells provide an explanation why cardiomyocytes are largely protected from direct CD8+ T‐cell‐mediated killing. PMID:26970349

  3. Three-dimensional direct measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections.

    Science.gov (United States)

    Bensley, Jonathan Guy; De Matteo, Robert; Harding, Richard; Black, Mary Jane

    2016-01-01

    Quantitative assessment of myocardial development and disease requires accurate measurement of cardiomyocyte volume, nuclearity (nuclei per cell), and ploidy (genome copies per cell). Current methods require enzymatically isolating cells, which excludes the use of archived tissue, or serial sectioning. We describe a method of analysis that permits the direct simultaneous measurement of cardiomyocyte volume, nuclearity, and ploidy in thick histological sections. To demonstrate the utility of our technique, heart tissue was obtained from four species (rat, mouse, rabbit, sheep) at up to three life stages: prenatal, weaning and adulthood. Thick (40 μm) paraffin sections were stained with Wheat Germ Agglutinin-Alexa Fluor 488 to visualise cell membranes, and DAPI (4',6-diamidino-2-phenylindole) to visualise nuclei and measure ploidy. Previous methods have been restricted to thin sections (2-10 μm) and offer an incomplete picture of cardiomyocytes. Using confocal microscopy and three-dimensional image analysis software (Imaris Version 8.2, Bitplane AG, Switzerland), cardiomyocyte volume, nuclearity, and ploidy were measured. This method of staining and analysis of cardiomyocytes enables accurate morphometric measurements in thick histological sections, thus unlocking the potential of archived tissue. Our novel time-efficient method permits the entire cardiomyocyte to be visualised directly in 3D, eliminating the need for precise alignment of serial sections.

  4. Role of salubrinal in protecting cardiomyocytes from doxorubicin-induced apoptosis.

    Science.gov (United States)

    Gong, N; Wu, J H; Liang, Z S; Jiang, W H; Wang, X W

    2015-01-01

    We determined whether salubrinal can protect cardio-myocytes from doxorubicin-induced apoptosis and explored the related mechanisms to provide experimental evidence for exploring novel drug candidates to decrease cardiac toxicity. Neonatal rat cardiomyocytes were isolated, cultured in vitro, and pretreated with salubrinal (10, 20, or 40 μM) to observe their response to doxorubicin-induced cell apoptosis. Lactate dehydrogenase assay, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling staining, and flow cytometry were used to assess the extent of cardiomyocyte apoptosis. Fluorescent probes conjugated with 2',7'-dichlorofluorescein diacetate and a chemiluminescence assay were used to detect the pro-duction of reactive oxygen species. Western blotting was employed to quantify expression levels of cleaved caspase-3, cytosolic cytochrome c, and B-cell lymphoma-extra large (Bcl-xL). The mechanisms of salubrinal-related functions were also explored. Salubrinal effectively inhibited doxorubicin-induced reactive oxygen species production and nicotinamide adenine dinucleotide phosphate oxidase activation, decreased the levels of cleaved caspase-3 and cytosol cytochrome c, and increased Bcl-xL expression, thereby protecting cardiomyocytes from doxorubicin-induced apoptosis. Furthermore, salubrinal was found to protect cardiomyocytes by decreasing the dephosphorylation of eukaryotic translation initiation factor 2α (eIF2α). Salubrinal can protect cardiomyocytes from doxorubicin-induced apoptosis through its effects on eIF2α. It possibly ameliorates cardiac toxicity and can be used in clinical practice. PMID:26505387

  5. MicroRNA-1 and-16 inhibit cardiomyocyte hypertrophy by targeting cyclins/Rb pathway

    Institute of Scientific and Technical Information of China (English)

    SHAN Zhi-xin; ZHU Jie-ning; TANG Chun-mei; ZHU Wen-si; LIN Qiu-xiong; HU Zhi-qin; FU Yong-heng; ZHANG Meng-zhen

    2016-01-01

    AIM:MicroRNAs ( miRNAs) were recognized to play significant roles in cardiac hypertrophy .But, it remains unknown whether cyclin/Rb pathway is modulated by miRNAs during cardiac hypertrophy .This study investigates the potential roles of microRNA-1 (miR-1) and microRNA-16 (miR-16) in modulating cyclin/Rb pathway during cardiomyocyte hypertrophy .METHODS:An animal model of hypertrophy was established in a rat with abdominal aortic constriction (AAC).In addition, a cell model of hypertrophy was also achieved based on PE-promoted neonatal rat ventricular cardiomyocyte .RESULTS:miR-1 and-16 expression were markedly de-creased in hypertrophic myocardium and hypertrophic cardiomyocytes in rats .Overexpression of miR-1 and -16 suppressed rat cardiac hypertrophy and hypertrophic phenotype of cultured cardiomyocytes .Expression of cyclins D1, D2 and E1, CDK6 and phosphorylated pRb was increased in hypertrophic myocardium and hypertrophic cardiomyocytes , but could be reversed by enforced expression of miR-1 and -16.CDK6 was validated to be modulated post-transcriptionally by miR-1, and cyclins D1, D2 and E1 were further validated to be modulated post-transcriptionally by miR-16.CONCLUSION: Attenuations of miR-1 and -16 provoke cardiomyocyte hypertrophy via derepressing the cyclins D1, D2, E1 and CDK6, and activating cyclin/Rb pathway.

  6. MiR-25 protects cardiomyocytes against oxidative damage by targeting the mitochondrial calcium uniporter.

    Science.gov (United States)

    Pan, Lei; Huang, Bi-Jun; Ma, Xiu-E; Wang, Shi-Yi; Feng, Jing; Lv, Fei; Liu, Yuan; Liu, Yi; Li, Chang-Ming; Liang, Dan-Dan; Li, Jun; Xu, Liang; Chen, Yi-Han

    2015-03-10

    MicroRNAs (miRNAs) are a class of small non-coding RNAs, whose expression levels vary in different cell types and tissues. Emerging evidence indicates that tissue-specific and -enriched miRNAs are closely associated with cellular development and stress responses in their tissues. MiR-25 has been documented to be abundant in cardiomyocytes, but its function in the heart remains unknown. Here, we report that miR-25 can protect cardiomyocytes against oxidative damage by down-regulating mitochondrial calcium uniporter (MCU). MiR-25 was markedly elevated in response to oxidative stimulation in cardiomyocytes. Further overexpression of miR-25 protected cardiomyocytes against oxidative damage by inactivating the mitochondrial apoptosis pathway. MCU was identified as a potential target of miR-25 by bioinformatical analysis. MCU mRNA level was reversely correlated with miR-25 under the exposure of H2O2, and MCU protein level was largely decreased by miR-25 overexpression. The luciferase reporter assay confirmed that miR-25 bound directly to the 3' untranslated region (UTR) of MCU mRNA. MiR-25 significantly decreased H2O2-induced elevation of mitochondrial Ca2+ concentration, which is likely to be the result of decreased activity of MCU. We conclude that miR-25 targets MCU to protect cardiomyocytes against oxidative damages. This finding provides novel insights into the involvement of miRNAs in oxidative stress in cardiomyocytes.

  7. Cardiomyocytes display low mitochondrial priming and are highly resistant toward cytotoxic T-cell killing.

    Science.gov (United States)

    Zheng, Xiang; Halle, Stephan; Yu, Kai; Mishra, Pooja; Scherr, Michaela; Pietzsch, Stefan; Willenzon, Stefanie; Janssen, Anika; Boelter, Jasmin; Hilfiker-Kleiner, Denise; Eder, Matthias; Förster, Reinhold

    2016-06-01

    Following heart transplantation, alloimmune responses can cause graft rejection by damaging donor vascular and parenchymal cells. However, it remains unclear whether cardiomyocytes are also directly killed by immune cells. Here, we used two-photon microscopy to investigate how graft-specific effector CD8(+) T cells interact with cardiomyocytes in a mouse heart transplantation model. Surprisingly, we observed that CD8(+) T cells are completely impaired in killing cardiomyocytes. Even after virus-mediated preactivation, antigen-specific CD8(+) T cells largely fail to lyse these cells although both cell types engage in dynamic interactions. Furthermore, we established a two-photon microscopy-based assay using intact myocardium to determine the susceptibility of cardiomyocytes to undergo apoptosis. This feature, also known as mitochondrial priming reveals an unexpected weak predisposition of cardiomyocytes to undergo apoptosis in situ. These observations together with the early exhaustion phenotype of graft-infiltrating specific T cells provide an explanation why cardiomyocytes are largely protected from direct CD8(+) T-cell-mediated killing. PMID:26970349

  8. [Erectile and Ejaculatory Dysfunction].

    Science.gov (United States)

    Gross, Oliver; Sulser, Tullio; Eberli, Daniel

    2015-11-25

    The inability to achieve an erection of the penis sufficient for sexual activity is called erectile dysfunction (ED). In most cases, the diagnosis can be made by medical history. The prevalence of ED in men at the age of 65 has been reported to be up to 50%. Premature ejaculation has a prevalence, up to 20% and is the most frequent ejaculatory dysfunction. The etiology of ED can involve psychological, vascular, neurogenic, hormonal or urogenital pathologies. The main pathophysiological mechanisms of ED are vascular disorders such as diabetes mellitus and atherosclerosis. Because of the common pathophysiology, patients diagnosed with ED should have a diagnostic work-up for systemic vascular pathologies to prevent concomitant cardiac events. Treatment options include invasive and non-invasive procedures. PMID:26602851

  9. Biology of Sexual Dysfunction

    OpenAIRE

    MN, Anil Kumar; Pai, NB; Rao, S.; Rao, TSS; Goyal, N.

    2009-01-01

    Sexual activity is a multifaceted activity, involving complex interactions between the nervous system, the endocrine system, the vascular system and a variety of structures that are instrumental in sexual excitement, intercourse and satisfaction. Sexual function has three components i.e., desire, arousal and orgasm. Many sexual dysfunctions can be categorized according to the phase of sexual response that is affected. In actual clinical practice however, sexual desire, arousal and orgasmic di...

  10. High-density lipoprotein, mitochondrial dysfunction and cell survival mechanisms.

    Science.gov (United States)

    White, C Roger; Giordano, Samantha; Anantharamaiah, G M

    2016-09-01

    Ischemic injury is associated with acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting and open heart surgery. The timely re-establishment of blood flow is critical in order to minimize cardiac complications. Reperfusion after a prolonged ischemic period, however, can induce severe cardiomyocyte dysfunction with mitochondria serving as a major target of ischemia/reperfusion (I/R) injury. An increase in the formation of reactive oxygen species (ROS) induces damage to mitochondrial respiratory complexes leading to uncoupling of oxidative phosphorylation. Mitochondrial membrane perturbations also contribute to calcium overload, opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic mediators into the cytoplasm. Clinical and experimental studies show that ischemic preconditioning (ICPRE) and postconditioning (ICPOST) attenuate mitochondrial injury and improve cardiac function in the context of I/R injury. This is achieved by the activation of two principal cell survival cascades: 1) the Reperfusion Injury Salvage Kinase (RISK) pathway; and 2) the Survivor Activating Factor Enhancement (SAFE) pathway. Recent data suggest that high density lipoprotein (HDL) mimics the effects of conditioning protocols and attenuates myocardial I/R injury via activation of the RISK and SAFE signaling cascades. In this review, we discuss the roles of apolipoproteinA-I (apoA-I), the major protein constituent of HDL, and sphingosine 1-phosphate (S1P), a lysosphingolipid associated with small, dense HDL particles as mediators of cardiomyocyte survival. Both apoA-I and S1P exert an infarct-sparing effect by preventing ROS-dependent injury and inhibiting the opening of the mPTP. PMID:27150975

  11. Cardiac Peroxisome Proliferator-Activated Receptor-γ Expression is Modulated by Oxidative Stress in Acutely Infrasound-Exposed Cardiomyocytes

    OpenAIRE

    Pei, Zhaohui; Meng, Rongsen; Zhuang, Zhiqiang; Zhao, Yiqiao; Liu, Fangpeng; Zhu, Miao-Zhang; Li, Ruiman

    2013-01-01

    The aim of the present study was to examine the effects of acute infrasound exposure on oxidative damage and investigate the underlying mechanisms in rat cardiomyocytes. Neonatal rat cardiomyocytes were cultured and exposed to infrasound for several days. In the study, the expression of CAT, GPx, SOD1, and SOD2 and their activities in rat cardiomyocytes in infrasound exposure groups were significantly decreased compared to those in the various time controls, along with significantly higher le...

  12. High levels of glucose induce "metabolic memory" in cardiomyocyte via epigenetic histone H3 lysine 9 methylation.

    Science.gov (United States)

    Yu, Xi-Yong; Geng, Yong-Jian; Liang, Jia-Liang; Zhang, Saidan; Lei, He-Ping; Zhong, Shi-Long; Lin, Qiu-Xiong; Shan, Zhi-Xin; Lin, Shu-Guang; Li, Yangxin

    2012-09-01

    Diabetic patients continue to develop inflammation and cardiovascular complication even after achieving glycemic control, suggesting a "metabolic memory". Metabolic memory is a major challenge in the treatment of diabetic complication, and the mechanisms underlying metabolic memory are not clear. Recent studies suggest a link between chromatin histone methylation and metabolic memory. In this study, we tested whether histone 3 lysine-9 tri-methylation (H3K9me3), a key epigenetic chromatin marker, was involved in high glucose (HG)-induced inflammation and metabolic memory. Incubating cardiomyocyte cells in HG resulted in increased levels of inflammatory cytokine IL-6 mRNA when compared with myocytes incubated in normal culture media, whereas mannitol (osmotic control) has no effect. Chromatin immunoprecipitation (ChIP) assays showed that H3K9me3 levels were significantly decreased at the promoters of IL-6. Immunoblotting demonstrated that protein levels of the H3K9me3 methyltransferase, Suv39h1, were also reduced after HG treatment. HG-induced apoptosis, mitochondrial dysfunction and cytochrome-c release were reversible. However, the effects of HG on the expression of IL-6 and the levels of H3K9me3 were irreversible after the removal of HG from the culture. These results suggest that HG-induced sustained inflammatory phenotype and epigenetic histone modification, rather than HG-induced mitochondrial dysfunction and apoptosis, are main mechanisms responsible for metabolic memory. In conclusion, our data demonstrate that HG increases expression of inflammatory cytokine and decreases the levels of histone-3 methylation at the cytokine promoter, and suggest that modulating histone 3 methylation and inflammatory cytokine expression may be a useful strategy to prevent metabolic memory and cardiomyopathy in diabetic patients. PMID:22707199

  13. Menthol inhibits detrusor contractility independently of TRPM8 activation.

    Directory of Open Access Journals (Sweden)

    Antonio Celso Saragossa Ramos-Filho

    Full Text Available Agonists such as icilin and menthol can activate the cool temperature-sensitive ion channel TRPM8. However, biological responses to menthol may occur independently of TRPM8 activation. In the rodent urinary bladder, menthol facilitates the micturition reflex but inhibits muscarinic contractions of the detrusor smooth muscle. The site(s of TRPM8 expression in the bladder are controversial. In this study we investigated the regulation of bladder contractility in vitro by menthol. Bladder strips from wild type and TRPM8 knockout male mice (25-30 g were dissected free and mounted in organ baths. Isometric contractions to carbachol (1 nM-30 µM, CaCl2 (1 µM to 100 mM and electrical field stimulation (EFS; 8, 16, 32 Hz were measured. Strips from both groups contracted similarly in response to both carbachol and EFS. Menthol (300 µM or nifedipine (1 µM inhibited carbachol and EFS-induced contractions in both wild type and TRPM8 knockout bladder strips. Incubation with the sodium channel blocker tetrodotoxin (1 µM, replacement of extracellular sodium with the impermeant cation N-Methyl-D-Glucamine, incubation with a cocktail of potassium channel inhibitors (100 nM charybdotoxin, 1 µM apamin, 10 µM glibenclamide and 1 µM tetraethylammonium or removal of the urothelium did not affect the inhibitory actions of menthol. Contraction to CaCl2 was markedly inhibited by either menthol or nifedipine. In cultured bladder smooth muscle cells, menthol or nifedipine abrogated the carbachol or KCl-induced increases in [Ca2+]i. Intravesical administration of menthol increased voiding frequency while decreasing peak voiding pressure. We conclude that menthol inhibits muscarinic bladder contractions through blockade of L-type calcium channels, independently of TRPM8 activation.

  14. Differential Expression Levels of Integrin α6 Enable the Selective Identification and Isolation of Atrial and Ventricular Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Anne Maria Wiencierz

    Full Text Available Central questions such as cardiomyocyte subtype emergence during cardiogenesis or the availability of cardiomyocyte subtypes for cell replacement therapy require selective identification and purification of atrial and ventricular cardiomyocytes. However, current methodologies do not allow for a transgene-free selective isolation of atrial or ventricular cardiomyocytes due to the lack of subtype specific cell surface markers.In order to develop cell surface marker-based isolation procedures for cardiomyocyte subtypes, we performed an antibody-based screening on embryonic mouse hearts. Our data indicate that atrial and ventricular cardiomyocytes are characterized by differential expression of integrin α6 (ITGA6 throughout development and in the adult heart. We discovered that the expression level of this surface marker correlates with the intracellular subtype-specific expression of MLC-2a and MLC-2v on the single cell level and thereby enables the discrimination of cardiomyocyte subtypes by flow cytometry. Based on the differential expression of ITGA6 in atria and ventricles during cardiogenesis, we developed purification protocols for atrial and ventricular cardiomyocytes from mouse hearts. Atrial and ventricular identities of sorted cells were confirmed by expression profiling and patch clamp analysis.Here, we introduce a non-genetic, antibody-based approach to specifically isolate highly pure and viable atrial and ventricular cardiomyocytes from mouse hearts of various developmental stages. This will facilitate in-depth characterization of the individual cellular subsets and support translational research applications.

  15. Sphincter of Oddi dysfunction and Pancreatitis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Sphincter of Oddi dysfunction (SOD) is a term used to describe a group of heterogenous pain syndromes caused by abnormalities in sphincter contractility. Biliary and pancreatic SOD are each sub-classified as type I,ⅡorⅢ, according to the Milwaukee classification. SOD appears to carry an increased risk of acute pancreatitis as well as rates of post ERCP pancreatitis of over 30%. Various mechanisms have been postulated but the exact role of SOD in the pathophysiology of acute pancreatitis is unknown. There is also an association between SOD and chronic pancreatitis but it is still unclear if this is a cause or effect relationship. Management of SOD is aimed at sphincter ablation, usually by endoscopic sphincterotomy (ES). Patients with typeⅠSOD will benefit from ES in 55%-95% of cases. Sphincter of Oddi manometry is not necessary before ES in type Ⅰ SOD. For patients with typesⅡandⅢthe benefit of ES is lower. These patients should be more thoroughly evaluated before performing ES. Some researchers have found that manometry and ablation of both the biliary and pancreatic sphincters is required to adequately assess and treat SOD. In pancreatic SOD up to 88% of patients will benefit from sphincterotomy. Therefore,there have been calls from some quarters for the current classification system to be scrapped in favour of an overall system encompassing both biliary and pancreatic types. Future work should be aimed at understanding the mechanisms underlying the relationship between SOD and pancreatitis and identifying patient factors that will help predict benefit from endoscopic therapy.

  16. Nitric Oxide Synthase 1 Modulates Basal and β-Adrenergic-Stimulated Contractility by Rapid and Reversible Redox-Dependent S-Nitrosylation of the Heart.

    Science.gov (United States)

    Vielma, Alejandra Z; León, Luisa; Fernández, Ignacio C; González, Daniel R; Boric, Mauricio P

    2016-01-01

    S-nitrosylation of several Ca2+ regulating proteins in response to β-adrenergic stimulation was recently described in the heart; however the specific nitric oxide synthase (NOS) isoform and signaling pathways responsible for this modification have not been elucidated. NOS-1 activity increases inotropism, therefore, we tested whether β-adrenergic stimulation induces NOS-1-dependent S-nitrosylation of total proteins, the ryanodine receptor (RyR2), SERCA2 and the L-Type Ca2+ channel (LTCC). In the isolated rat heart, isoproterenol (10 nM, 3-min) increased S-nitrosylation of total cardiac proteins (+46±14%) and RyR2 (+146±77%), without affecting S-nitrosylation of SERCA2 and LTCC. Selective NOS-1 blockade with S-methyl-L-thiocitrulline (SMTC) and Nω-propyl-l-arginine decreased basal contractility and relaxation (-25-30%) and basal S-nitrosylation of total proteins (-25-60%), RyR2, SERCA2 and LTCC (-60-75%). NOS-1 inhibition reduced (-25-40%) the inotropic response and protein S-nitrosylation induced by isoproterenol, particularly that of RyR2 (-85±7%). Tempol, a superoxide scavenger, mimicked the effects of NOS-1 inhibition on inotropism and protein S-nitrosylation; whereas selective NOS-3 inhibitor L-N5-(1-Iminoethyl)ornithine had no effect. Inhibition of NOS-1 did not affect phospholamban phosphorylation, but reduced its oligomerization. Attenuation of contractility was abolished by PKA blockade and unaffected by guanylate cyclase inhibition. Additionally, in isolated mouse cardiomyocytes, NOS-1 inhibition or removal reduced the Ca2+-transient amplitude and sarcomere shortening induced by isoproterenol or by direct PKA activation. We conclude that 1) normal cardiac performance requires basal NOS-1 activity and S-nitrosylation of the calcium-cycling machinery; 2) β-adrenergic stimulation induces rapid and reversible NOS-1 dependent, PKA and ROS-dependent, S-nitrosylation of RyR2 and other proteins, accounting for about one third of its inotropic effect.

  17. A critical role of cardiac fibroblast-derived exosomes in activating renin angiotensin system in cardiomyocytes.

    Science.gov (United States)

    Lyu, Linmao; Wang, Hui; Li, Bin; Qin, Qingyun; Qi, Lei; Nagarkatti, Mitzi; Nagarkatti, Prakash; Janicki, Joseph S; Wang, Xing Li; Cui, Taixing

    2015-12-01

    Chronic activation of the myocardial renin angiotensin system (RAS) elevates the local level of angiotensin II (Ang II) thereby inducing pathological cardiac hypertrophy, which contributes to heart failure. However, the precise underlying mechanisms have not been fully delineated. Herein we report a novel paracrine mechanism between cardiac fibroblasts (CF)s and cardiomyocytes whereby Ang II induces pathological cardiac hypertrophy. In cultured CFs, Ang II treatment enhanced exosome release via the activation of Ang II receptor types 1 (AT1R) and 2 (AT2R), whereas lipopolysaccharide, insulin, endothelin (ET)-1, transforming growth factor beta (TGFβ)1 or hydrogen peroxide did not. The CF-derived exosomes upregulated the expression of renin, angiotensinogen, AT1R, and AT2R, downregulated angiotensin-converting enzyme 2, and enhanced Ang II production in cultured cardiomyocytes. In addition, the CF exosome-induced cardiomyocyte hypertrophy was blocked by both AT1R and AT2R antagonists. Exosome inhibitors, GW4869 and dimethyl amiloride (DMA), inhibited CF-induced cardiomyocyte hypertrophy with little effect on Ang II-induced cardiomyocyte hypertrophy. Mechanistically, CF exosomes upregulated RAS in cardiomyocytes via the activation of mitogen-activated protein kinases (MAPKs) and Akt. Finally, Ang II-induced exosome release from cardiac fibroblasts and pathological cardiac hypertrophy were dramatically inhibited by GW4869 and DMA in mice. These findings demonstrate that Ang II stimulates CFs to release exosomes, which in turn increase Ang II production and its receptor expression in cardiomyocytes, thereby intensifying Ang II-induced pathological cardiac hypertrophy. Accordingly, specific targeting of Ang II-induced exosome release from CFs may serve as a novel therapeutic approach to treat cardiac pathological hypertrophy and heart failure.

  18. Diabetic bladder dysfunction

    Institute of Scientific and Technical Information of China (English)

    Guiming Liu; Firouz Daneshgari

    2014-01-01

    Objective To review studies on diabetic bladder dysfunction (DBD),a common and bothersome complication of diabetes mellitus.Data sources We performed a search of the English literature through PubMed.The key words used were "diabetes" and "bladder dysfunction" or "cystopathy".Our own data and perspective are included in the discussion.Study selection Studies containing data relevant to DBD were selected.Because of the limited length of this article,we also referenced reviews that contain comprehensive amalgamations of relevant literature.Results The classic symptoms of DBD are decreased bladder sensation,increased bladder capacity,and impaired bladder emptying with resultant elevated post-void residual urine.However,recent clinical and experimental evidence indicate a strong presence of storage problems such as urge incontinence in diabetes.Recent studies of DBD in animal models of type 1 diabetes have revealed temporal effects of diabetes,causing an early phase of compensatory bladder function and a later phase of decompensated bladder function.The pathophysiology of DBD is multifactorial,including disturbances of the detrusor,urothelium,autonomic nerves,and urethra.Polyuria and hyperglycemia play important but distinctive roles in induction of bladder dysfunction in type 1 diabetes.Polyuria causes significant bladder hypertrophy in the early stage of diabetes,whereas oxidative stress in the bladder caused by chronic hyperglycemia may play an important role in the late stage failure of bladder function.Conclusions DBD includes time-dependent and mixed manifestations.The pathological alterations include muscle,nerve,and urothelium.Polyuria and hyperglycemia independently contribute to the pathogenesis of DBD.Treatments for DBD are limited.Future clinical studies on DBD in type 1 and type 2 diabetes should be investigated separately.Animal studies of DBD in type 2 diabetes are needed,from the natural history to mechanisms.Further understanding of the molecular

  19. The erectile dysfunction

    Directory of Open Access Journals (Sweden)

    Johan Eduardo Ardila Jaimes

    2002-12-01

    Full Text Available The erectile dysfunction (ED is a high prevalence disorderassociated to psychological and mainly organic factors thatcan affect at men of any age. The increase of the knowledgeof the physiologic mechanisms of the masculine erection andthe development of new agents that improve the erectilefunction have generated great interest among the physicians,the men and their couples because these advances areextending the available options in the management of thisdisorder. In this article we revise the etiologic andphysiopathologic aspects, as well as the clinical focus andthe current management of the ED.

  20. Angiotensin II Induced Cardiac Dysfunction on a Chip.

    Science.gov (United States)

    Horton, Renita E; Yadid, Moran; McCain, Megan L; Sheehy, Sean P; Pasqualini, Francesco S; Park, Sung-Jin; Cho, Alexander; Campbell, Patrick; Parker, Kevin Kit

    2016-01-01

    In vitro disease models offer the ability to study specific systemic features in isolation to better understand underlying mechanisms that lead to dysfunction. Here, we present a cardiac dysfunction model using angiotensin II (ANG II) to elicit pathological responses in a heart-on-a-chip platform that recapitulates native laminar cardiac tissue structure. Our platform, composed of arrays of muscular thin films (MTF), allows for functional comparisons of healthy and diseased tissues by tracking film deflections resulting from contracting tissues. To test our model, we measured gene expression profiles, morphological remodeling, calcium transients, and contractile stress generation in response to ANG II exposure and compared against previous experimental and clinical results. We found that ANG II induced pathological gene expression profiles including over-expression of natriuretic peptide B, Rho GTPase 1, and T-type calcium channels. ANG II exposure also increased proarrhythmic early after depolarization events and significantly reduced peak systolic stresses. Although ANG II has been shown to induce structural remodeling, we control tissue architecture via microcontact printing, and show pathological genetic profiles and functional impairment precede significant morphological changes. We assert that our in vitro model is a useful tool for evaluating tissue health and can serve as a platform for studying disease mechanisms and identifying novel therapeutics.

  1. Angiotensin II Induced Cardiac Dysfunction on a Chip.

    Directory of Open Access Journals (Sweden)

    Renita E Horton

    Full Text Available In vitro disease models offer the ability to study specific systemic features in isolation to better understand underlying mechanisms that lead to dysfunction. Here, we present a cardiac dysfunction model using angiotensin II (ANG II to elicit pathological responses in a heart-on-a-chip platform that recapitulates native laminar cardiac tissue structure. Our platform, composed of arrays of muscular thin films (MTF, allows for functional comparisons of healthy and diseased tissues by tracking film deflections resulting from contracting tissues. To test our model, we measured gene expression profiles, morphological remodeling, calcium transients, and contractile stress generation in response to ANG II exposure and compared against previous experimental and clinical results. We found that ANG II induced pathological gene expression profiles including over-expression of natriuretic peptide B, Rho GTPase 1, and T-type calcium channels. ANG II exposure also increased proarrhythmic early after depolarization events and significantly reduced peak systolic stresses. Although ANG II has been shown to induce structural remodeling, we control tissue architecture via microcontact printing, and show pathological genetic profiles and functional impairment precede significant morphological changes. We assert that our in vitro model is a useful tool for evaluating tissue health and can serve as a platform for studying disease mechanisms and identifying novel therapeutics.

  2. Unique metabolic features of stem cells, cardiomyocytes, and their progenitors.

    Science.gov (United States)

    Gaspar, John Antonydas; Doss, Michael Xavier; Hengstler, Jan Georg; Cadenas, Cristina; Hescheler, Jürgen; Sachinidis, Agapios

    2014-04-11

    Recently, growing attention has been directed toward stem cell metabolism, with the key observation that the plasticity of stem cells also reflects the plasticity of their energy substrate metabolism. There seems to be a clear link between the self-renewal state of stem cells, in which cells proliferate without differentiation, and the activity of specific metabolic pathways. Differentiation is accompanied by a shift from anaerobic glycolysis to mitochondrial respiration. This metabolic switch of differentiating stem cells is required to cover the energy demands of the different organ-specific cell types. Among other metabolic signatures, amino acid and carbohydrate metabolism is most prominent in undifferentiated embryonic stem cells, whereas the fatty acid metabolic signature is unique in cardiomyocytes derived from embryonic stem cells. Identifying the specific metabolic pathways involved in pluripotency and differentiation is critical for further progress in the field of developmental biology and regenerative medicine. The recently generated knowledge on metabolic key processes may help to generate mature stem cell-derived somatic cells for therapeutic applications without the requirement of genetic manipulation. In the present review, the literature about metabolic features of stem cells and their cardiovascular cell derivatives as well as the specific metabolic gene signatures differentiating between stem and differentiated cells are summarized and discussed.

  3. THE IMPROVEMENT OF INFARCTED MYOCARDIAL CONTRACTILE FORCE AFTER AUTOLOGOUS SKELETAL MUSCLE SATELLITE CELL IMPLANTATION

    Institute of Scientific and Technical Information of China (English)

    钟竑; 朱洪生; 张臻

    2002-01-01

    Objective To study the improvement of infarcted myocardial contractile force after autologous skeletal muscle satellite cell implantation via intracoronary arterial perfusion. Methods Skeletal muscle cells were harvested from gluteus max of adult mongrel dogs and the cells were cultured and expanded before being labeled with DAPI (4, 6-diamidino-2-phenylindone). The labeled cells were then implanted into the acute myocardial infarct site via the ligated left anterior descending (LAD) coronary artery. Specimens were taken at 2nd, 4th, 8th week after myoblast implantation for histologic and contractile force evaluation, respectively. Results The satellite cells with fluorescence had been observed in the infarct site and also in papi-llary muscle with consistent oriented direction of host myocardium. A portion of the implanted cells had differen-tiated into muscle fibers. Two weeks after implantation, the myocardial contractile force showed no significant difference between the cell implant group and control group. At 4 and 8 week, the contractile force in the cell implant group was better than that in control group. Conclusion The skeletal muscle satellite cells, implanted into infarct myocardium by intracoronary arterial perfusion, could disseminate through the entire infarcted zone with myocardial regeneration and improve the contractile function of the infarcted myocardium.

  4. Diastolic dysfunction in cirrhosis.

    Science.gov (United States)

    Møller, Søren; Wiese, Signe; Halgreen, Hanne; Hove, Jens D

    2016-09-01

    Development of esophageal varices, ascites, and hepatic nephropathy is among the major complications of cirrhosis. The presence of cirrhotic cardiomyopathy, which includes a left ventricular diastolic dysfunction (DD), seems to deteriorate the course of the disease and the prognosis. Increased stiffness of the cirrhotic heart may decrease the compliance and result in DD. The prevalence of DD in cirrhotic patients averages about 50 %. It can be evaluated by transmitral Doppler echocardiography, tissue Doppler echocardiography, and cardiac magnetic resonance imaging. There seems to be a relation between DD and the severity of liver dysfunction and the presence of ascites. After liver transplantation, DD worsens the prognosis and increases the risk of graft rejection, but DD improves after few months. Insertion of a transjugular intrahepatic portosystemic shunt increases left ventricular diastolic volumes, and DD is a predictor of poorer survival in these patients. Future studies should aim at disclosing pathophysiological mechanisms behind the developing of DD in cirrhosis in relation to patient characteristics, development of complications, treatment, and risk associated with interventional procedures. PMID:27075496

  5. Autoantibody against Cardiac β1-Adrenoceptor Induces Apoptosis in Cultured Neonatal Rat Cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    Yan GAO; Hui-Rong LIU; Rong-Rui ZHAO; Jian-Ming ZHI

    2006-01-01

    To clarify whether apoptosis is involved in the injury processes induced by autoantibody against cardiac β1-adrenoceptor, we investigated the biological and apoptotic effects of antibodies on cultured neonatal rat cardiomyocytes. Wistar rats were immunized with peptides corresponding to the second extracellular loop of the β1-adrenoceptor to induce the production of anti-β1-adrenoceptor antibodies in the sera.Immunoglobulin (Ig) G in the sera was detected using synthetic antigen enzyme-linked immunosorbent assay and purified using the diethylaminoethyl cellulose ion exchange technique. Apoptosis of cardiomyocytes was evaluated using agarose gel electrophoresis and flow cytometry. Our results showed that the positive serum IgG greatly increased the beating rates of cardiomyocytes and showed an "agonist-like" activity. Furthermore, positive serum IgG induced cardiomyocyte apoptosis after treatment with β1adrenoceptor overstimulation for 48 h. The effects of monoclonal antibody against β1-adrenoceptor were also found to be similar to those of positive serum IgG. It was suggested that the autoantibody could induce cardiomyocyte apoptosis by excessive stimulation of β1-adrenoceptor.

  6. Passage-restricted differentiation potential of mesenchymal stem cells into cardiomyocyte-like cells

    International Nuclear Information System (INIS)

    Mesenchymal stem cells (MSCs) have limited ability to differentiate into cardiomyocytes and the factors affect this process are not fully understood. In this study, we investigated the passage (P)-related transdifferentiation potential of MSCs into cardiomyocyte-like cells and its relationship to the proliferation ability. After 5-azacytidine treatment, only P4 but not P1 and P8 rat bone marrow MSCs (rMSCs) showed formation of myotube and expressed cardiomyocyte-associated markers. The growth property analysis showed P4 rMSCs had a growth-arrest appearance, while P1 and P8 rMSCs displayed an exponential growth pattern. When the rapid proliferation of P1 and P8 rMSCs was inhibited by 5-bromo-2-deoxyuridine, a mitosis inhibitor, only P1, not P8 rMSCs, differentiated into cardiomyocyte-like cells after 5-azacytidine treatment. These results demonstrate that the differentiation ability of rMSCs into cardiomyocytes is in proliferation ability-dependent and passage-restricted patterns. These findings reveal a novel regulation on the transdifferentiation of MSCs and provide useful information for exploiting the clinical therapeutic potential of MSCs

  7. HMGB1 mediates hyperglycaemia-induced cardiomyocyte apoptosis via ERK/Ets-1 signalling pathway.

    Science.gov (United States)

    Wang, Wen-Ke; Lu, Qing-Hua; Zhang, Jia-Ning; Wang, Ben; Liu, Xiang-Juan; An, Feng-Shuang; Qin, Wei-Dong; Chen, Xue-Ying; Dong, Wen-Qian; Zhang, Cheng; Zhang, Yun; Zhang, Ming-Xiang

    2014-11-01

    Apoptosis is a key event involved in diabetic cardiomyopathy. The expression of high mobility group box 1 protein (HMGB1) is up-regulated in diabetic mice. However, the molecular mechanism of high glucose (HG)-induced cardiomyocyte apoptosis remains obscure. We aimed to determine the role of HMGB1 in HG-induced apoptosis of cardiomyocytes. Treating neonatal primary cardiomyocytes with HG increased cell apoptosis, which was accompanied by elevated levels of HMGB1. Inhibition of HMGB1 by short-hairpin RNA significantly decreased HG-induced cell apoptosis by reducing caspase-3 activation and ratio of Bcl2-associated X protein to B-cell lymphoma/leukemia-2 (bax/bcl-2). Furthermore, HG activated E26 transformation-specific sequence-1 (Ets-1), and HMGB1 inhibition attenuated HG-induced activation of Ets-1 via extracellular signal-regulated kinase 1/2 (ERK1/2) signalling. In addition, inhibition of Ets-1 significantly decreased HG-induced cardiomyocyte apoptosis. Similar results were observed in streptozotocin-treated diabetic mice. Inhibition of HMGB1 by short-hairpin RNA markedly decreased myocardial cell apoptosis and activation of ERK and Ets-1 in diabetic mice. In conclusion, inhibition of HMGB1 may protect against hyperglycaemia-induced cardiomyocyte apoptosis by down-regulating ERK-dependent activation of Ets-1.

  8. Nonhematopoietic erythropoietin derivative protects cardiomyocytes from hypoxia/reoxygenation-induced apoptosis

    Institute of Scientific and Technical Information of China (English)

    Xuan Xu; Xiaohong Shan; Zhijuan Cao; Meiling Wu; Qi Chen; Yuehua Li

    2008-01-01

    Objective:Carbamylated EPO(CEPO) is a derivative of erythropoietin(EPO) by subjecting it to carbamylation. It does not stimulate erythropoiesis, but effectively protects tissue from injury. The present study was to investigate the effect of CEPO treatment using in vitro models of hypoxia/reoxygenation(H/R). Methods:Cardiomyocytes were exposed to hypoxia(95% N2 and 5% CO2) for 1 hour followed by 4 hours of reoxygenation(95% O2 and 5% CO2). CEPO was administered after hypoxia, just before reoxygenation. The apoptotic cardiomyocytes were determined by flow cytometry. The level of protein was assessed by western blot analysis. Results: CEPO treatment significantly decreased the apoptotic cardiomyocytes by 54.20% compared with H/R group. Western blot analysis showed that CEPO administration increased the level of Bcl-2(an antiapoptotic protein) by 62.22% compared with H/R group. Conclusion: Acute administration of CEPO protected cardiomyocytes from H/R-induced apoptosis. CEPO protected cardiomyocytes with a concomitant upregulation of Bcl-2 after H/R injury.

  9. Talin Is Required Continuously for Cardiomyocyte Remodeling during Heart Growth in Drosophila.

    Directory of Open Access Journals (Sweden)

    Simina Bogatan

    Full Text Available Mechanotransduction of tension can govern the remodeling of cardiomyocytes during growth or cardiomyopathy. Tension is signaled through the integrin adhesion complexes found at muscle insertions and costameres but the relative importance of signalling during cardiomyocyte growth versus remodelling has not been assessed. Employing the Drosophila cardiomyocyte as a genetically amenable model, we depleted the levels of Talin, a central component of the integrin adhesion complex, at different stages of heart growth and remodeling. We demonstrate a continuous requirement for Talin during heart growth to maintain the one-to-one apposition of myofibril ends between cardiomyocytes. Retracted myofibrils cannot regenerate appositions to adjacent cells after restoration of normal Talin expression, and the resulting deficit reduces heart contraction and lifespan. Reduction of Talin during heart remodeling after hatching or during metamorphosis results in pervasive degeneration of cell contacts, myofibril length and number, for which restored Talin expression is insufficient for regeneration. Resultant dilated cardiomyopathy results in a fibrillating heart with poor rhythmicity. Cardiomyocytes have poor capacity to regenerate deficits in myofibril orientation and insertion, despite an ongoing capacity to remodel integrin based adhesions.

  10. Nrf2-Mediated Cardiac Maladaptive Remodeling and Dysfunction in a Setting of Autophagy Insufficiency.

    Science.gov (United States)

    Qin, Qingyun; Qu, Chen; Niu, Ting; Zang, Huimei; Qi, Lei; Lyu, Linmao; Wang, Xuejun; Nagarkatti, Mitzi; Nagarkatti, Prakash; Janicki, Joseph S; Wang, Xing Li; Cui, Taixing

    2016-01-01

    Nuclear factor erythroid-2-related factor 2 (Nrf2) appears to exert either a protective or detrimental effect on the heart; however, the underlying mechanism remains poorly understood. Herein, we uncovered a novel mechanism for turning off the Nrf2-mediated cardioprotection and switching on Nrf2-mediated cardiac dysfunction. In a murine model of pressure overload-induced cardiac remodeling and dysfunction via transverse aortic arch constriction, knockout of Nrf2 enhanced myocardial necrosis and death rate during an initial stage of cardiac adaptation when myocardial autophagy function is intact. However, knockout of Nrf2 turned out to be cardioprotective throughout the later stage of cardiac maladaptive remodeling when myocardial autophagy function became insufficient. Transverse aortic arch constriction -induced activation of Nrf2 was dramatically enhanced in the heart with impaired autophagy, which is induced by cardiomyocyte-specific knockout of autophagy-related gene (Atg)5. Notably, Nrf2 activation coincided with the upregulation of angiotensinogen (Agt) only in the autophagy-impaired heart after transverse aortic arch constriction. Agt5 and Nrf2 gene loss-of-function approaches in combination with Jak2 and Fyn kinase inhibitors revealed that suppression of autophagy inactivated Jak2 and Fyn and nuclear translocation of Fyn, while enhancing nuclear translocation of Nrf2 and Nrf2-driven Agt expression in cardiomyocytes. Taken together, these results indicate that the pathophysiological consequences of Nrf2 activation are closely linked with the functional integrity of myocardial autophagy during cardiac remodeling. When autophagy is intact, Nrf2 is required for cardiac adaptive responses; however, autophagy impairment most likely turns off Fyn-operated Nrf2 nuclear export thus activating Nrf2-driven Agt transcription, which exacerbates cardiac maladaptation leading to dysfunction. PMID:26573705

  11. Uterine dysfunction in biglycan and decorin deficient mice leads to dystocia during parturition.

    Directory of Open Access Journals (Sweden)

    Zhiping Wu

    Full Text Available Cesarean birth rates are rising. Uterine dysfunction, the exact mechanism of which is unknown, is a common indication for Cesarean delivery. Biglycan and decorin are two small leucine-rich proteoglycans expressed in the extracellular matrix of reproductive tissues and muscle. Mice deficient in biglycan display a mild muscular dystrophy, and, along with mice deficient in decorin, are models of Ehlers-Danlos Syndrome, a connective tissue anomaly associated with uterine rupture. As a variant of Ehlers-Danlos Syndrome is caused by a genetic mutation resulting in abnormal biglycan and decorin secretion, we hypothesized that biglycan and decorin play a role in uterine function. Thus, we assessed wild-type, biglycan, decorin and double knockout pregnancies for timing of birth and uterine function. Uteri were harvested at embryonic days 12, 15 and 18. Nonpregnant uterine samples of the same genotypes were assessed for tissue failure rate and spontaneous and oxytocin-induced contractility. We discovered that biglycan/decorin mixed double-knockout dams displayed dystocia, were at increased risk of delayed labor onset, and showed increased tissue failure in a predominantly decorin-dependent manner. In vitro spontaneous uterine contractile amplitude and oxytocin-induced contractile force were decreased in all biglycan and decorin knockout genotypes compared to wild-type. Notably, we found no significant compensation between biglycan and decorin using quantitative real time PCR or immunohistochemistry. We conclude that the biglycan/decorin mixed double knockout mouse is a model of dystocia and delayed labor onset. Moreover, decorin is necessary for uterine function in a dose-dependent manner, while biglycan exhibits partial compensatory mechanisms in vivo. Thus, this model is poised for use as a model for testing novel targets for preventive or therapeutic manipulation of uterine dysfunction.

  12. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies.

    Science.gov (United States)

    Dasbiswas, K; Alster, E; Safran, S A

    2016-01-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range "macroscopic modes" in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development. PMID:27283037

  13. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies

    Science.gov (United States)

    Dasbiswas, K.; Alster, E.; Safran, S. A.

    2016-06-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range “macroscopic modes” in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development.

  14. Myocardial ischemia-reperfusion induces upregulation of contractile endothelin ETB receptor in rat coronary arteries

    DEFF Research Database (Denmark)

    Skovsted, Gry Freja; Sheykhzade, Majid; Trautner, Simon;

    2011-01-01

    are situated in the vascular smooth muscle cells mediating vasoconstriction. This study aims to examine whether heart ischemia-reperfusion leads to upregulation of contractile ETB receptors in the smooth muscle layer of the coronary arteries and to investigate the signaling pathways involved in the putative...... ETB receptor upregulation. Methods and Results Thirteen Sprague-Dawley male rats (body weight 260-410 g) were anaesthetized with Hypnorm-Midazolam and subjected to 15 min occlusion of left anterior descending coronary artery (LAD) followed by 22 h of reperfusion. The contractile response...... of contractile ETB receptors in the vascular smooth muscle cells in coronary arteries in the post-ischemic area. This study suggests that the upregulation of the ETB receptors depends on a transcriptional upregulation and involves the MEK/ERK type of MAPK....

  15. Study of myogenic spontaneous contractile activities in the detrusor instability rats

    Institute of Scientific and Technical Information of China (English)

    JIANG Hai-hong; WEN Qian-jun; SONG Bo

    2006-01-01

    Objective: To explore a myogenic basis of the spontaneous contractions on the rat bladder smooth muscle strip in a detrusor instability (DI) model in vitro, and to study a nerve blocker's cocktail affecting the spontaneous contractions as well as electrical stimulated contractile response. Methods: DI model rats were made by partial bladder outlet obstruction (BOO) and confirmed by the filling cystometry. Detrusor strip was dissected from fresh bladder, fixed for an isometric tension trial. The contractions were recorded during electrical stimulation or exposure to some agents. Results: The cocktail diminished the nerve-mediated contractile response effectively in DI preparation. DI's spontaneous contractions remained during the presence of the cocktail with a significant change in its contractile amplitude. Conclusion: With the local nerve-concerned factors abolishment by the cocktail, the DI bladder preparations still have the spontaneous contractions, indicating a myogenic basis from themselves.

  16. Transforming growth factor-beta 1 specifically induce proteins involved in the myofibroblast contractile apparatus

    DEFF Research Database (Denmark)

    Malmström, Johan; Lindberg, Henrik Have; Lindberg, Claes;

    2004-01-01

    pattern changes that were identified by mass spectrometry and represent specific induction of several members of the contractile apparatus such as calgizzarin, cofilin, and profilin. These proteins have not previously been shown to be regulated by TGF-beta(1), and the functional role of these proteins...... is to participate in the depolymerization and stabilization of the microfilaments. These results show that TGF-beta(1) induces not only alpha-SMA but a whole set of actin-associated proteins that may contribute to the increased contractile properties of the myofibroblast. These proteins accompany the induced...... expression of alpha-SMA and may participate in the formation of stress fibers, cell contractility, and cell spreading characterizing the myofibroblasts phenotype....

  17. EFFECTS OF DESENSITIZATION AND REBOUND TO ADENOSINE ON ACTION POTENTIAL AND CONTRACTILITY IN ATRIAL CELLS IN GUINEA-PIGS

    Institute of Scientific and Technical Information of China (English)

    张凤杰; 臧伟进; 于晓江; 胡浩; 张春虹; 孙强; 吕军

    2002-01-01

    Objective To investigate the effects of desensitization and rebound to adenosine(Ado) on action potential duration(APD) and contractility in guinea-pig atrial cells. Methods Electrical activity was recorded using standard intracellular microelectrode technique and contractility was recorded using. We studied the effects of adenosine on the action potential and desensitization of contractility and rebound of contractility. Results The results showed that action potential duration were shortened by 1,10,100μmol*L-1Ado, the ratio of shortened APD was (9.58±1.40)%,(13.80±2.26)%,(24.80±3.19)%, respectively. 1μmol*L-1Ado had no desensitization (P>0.05), but the time of desensitization of 10μmol*L-1 Ado and 100μmol*L-1 Ado was 1 minute(P<0.05) and 5 minutes(P<0.05), respectively. The desensitization of contractility of 10*!μmol*L-1 Ado was obvious in atrial cells, the decrease of contractility of 10*!μmol*L-1 Ado was obvious in atrial cells, the decrease of contractility was changed from (31.4±16.04)%(2 minutes) to (50.60±15.87)% (4 minutes), compared with control. After washing out Ado, contractility was shown to rebound, the ratio of increase of contractility by 1,10,100μmol*L-1 Ado was (12.38±7.50)%,(19.00±8.14)% and (27.60±13.44)%, respectively. Conclusion Ado can abbreviate APD in atrial cells. The desensitization of Ado on APD is characterized by concentration-dependent and time-dependent in atrial cells, and the desensitization of contractility of Ado is obvious and contractility was shown to rebound after washing out Ado.

  18. [Thyroid dysfunction in pregnancy].

    Science.gov (United States)

    Führer, D; Mann, K; Feldkamp, J; Krude, H; Spitzweg, C; Kratzsch, J; Schott, M

    2014-10-01

    Thyroid dysfunction may impair fertility, course of pregnancy and fetal development. Physiological alterations of thyroid function parameters, that occur during pregnancy need to be distinguished from pathophysiological states of hypo- and hyperthyroidism. We performed a literature search (PubMed 1990-2013) and review relevant publications as well as consensus and practice guidelines of international thyroid/endocrine societies. Interpretation of thyroid function values in pregnancy must be based on trimester-specific TSH and T4 ranges. Alterations in thyroid function are present in up to 15% of pregnancies (0.4% overt hypothyroidism, 0.1-0.4% hyperthyroidism) and may lead to preventable complications in the pregnant woman and the fetus. Hypothyroidism is associated with an increased risk for abortion, premature delivery and stillbirth, besides impairment of neurocognitive development. The latter has also been shown in situations of grave iodine deficiency. In addition to new-born screening directed at early recognition of congenital hypothyroidism (incidence 0.03%), universal screening of all pregnant women should be implemented in health care guidelines. Newly diagnosed overt hypothyroidism in a pregnant woman requires immediate levothyroxine substitution at adequate doses. In subclinical hypothyroidism thyroid hormone replacement should be considered. Iodine supplementation is strongly recommended in all pregnant and breast-feeding women. Pregnancy causes a number of, that need to be of thyroid dysfunction. Both hypothyroidism and thyrotoxicosis may impair the course of pregnancy and may negatively affect the fetus. In particular, maternal hypothyroidism may lead to irreparable and detrimental deficits in the neurocognitive development of the fetus. Autoimmune thyroid disease is the most common cause of thyroid dysfunction in pregnancy. Hashimoto's thyroiditis is associated with impaired fertility and miscarriage, and may first manifest in pregnancy due to the

  19. The characteristics of action potential and nonselec-tive cation current of cardiomyocytes in rabbit superior vena cava

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    As a special focus in initiating and maintaining atrial fibrillation (AF), cardiomyocytes in superior vena cava (SVC) have distinctive electrophysiological characters. In this study, we found that comparing with the right atrial (RA) cardiomyoctyes, the SVC cardiomyoctyes had longer APD90 at the different basic cycle lengths; the conduction block could be observed on both RA and SVC cardiomyoctyes. A few of SVC cardiomyoctyes showed slow response action potentials with automatic activity and some others showed early afterdepolarization (EAD) spontaneously. Further more, we found that there are nonselective cation current (INs) in both SVC and RA cardiomyocytes. The peak density of INs in SVC cardiomyocytes was smaller than that in RA cardiomyocytes. Removal of extracellular divalent cation and glucose could increase INs in SVC cardiomyocytes. The agonist or the antagonist of INs may in-crease or decrease APD. To sum up, some SVC cardiomyocytes possess the ability of spontaneous activity; the difference of transmembrane action potentials between SVC and RA cardiomyocytes is partly because of the different density of INs between them; the agonist or the antagonist of INs can in-crease or decrease APD leading to the enhancement or reduction of EAD genesis in SVC cardiomyo-cytes. INs in rabbit myocytes is fairly similar to TRPC3 current in electrophysiological property, which might play an important role in the mechanisms of AF.

  20. Spatially Resolved Genome-wide Transcriptional Profiling Identifies BMP Signaling as Essential Regulator of Zebrafish Cardiomyocyte Regeneration

    NARCIS (Netherlands)

    Wu, Chi-Chung; Kruse, Fabian; Vasudevarao, Mohankrishna Dalvoy; Junker, Jan Philipp; Zebrowski, David C; Fischer, Kristin; Noël, Emily S; Grün, Dominic; Berezikov, Eugene; Engel, Felix B; van Oudenaarden, Alexander; Weidinger, Gilbert; Bakkers, Jeroen

    2016-01-01

    In contrast to mammals, zebrafish regenerate heart injuries via proliferation of cardiomyocytes located near the wound border. To identify regulators of cardiomyocyte proliferation, we used spatially resolved RNA sequencing (tomo-seq) and generated a high-resolution genome-wide atlas of gene express

  1. Stimulation of the cardiopulmonary baroreflex enhances ventricular contractility in awake dogs: a mathematical analysis study.

    Science.gov (United States)

    Sala-Mercado, Javier A; Moslehpour, Mohsen; Hammond, Robert L; Ichinose, Masashi; Chen, Xiaoxiao; Evan, Sell; O'Leary, Donal S; Mukkamala, Ramakrishna

    2014-08-15

    The cardiopulmonary baroreflex responds to an increase in central venous pressure (CVP) by decreasing total peripheral resistance and increasing heart rate (HR) in dogs. However, the direction of ventricular contractility change is not well understood. The aim was to elucidate the cardiopulmonary baroreflex control of ventricular contractility during normal physiological conditions via a mathematical analysis. Spontaneous beat-to-beat fluctuations in maximal ventricular elastance (Emax), which is perhaps the best available index of ventricular contractility, CVP, arterial blood pressure (ABP), and HR were measured from awake dogs at rest before and after β-adrenergic receptor blockade. An autoregressive exogenous input model was employed to jointly identify the three causal transfer functions relating beat-to-beat fluctuations in CVP to Emax (CVP → Emax), which characterizes the cardiopulmonary baroreflex control of ventricular contractility, ABP to Emax, which characterizes the arterial baroreflex control of ventricular contractility, and HR to Emax, which characterizes the force-frequency relation. The CVP → Emax transfer function showed a static gain of 0.037 ± 0.010 ml(-1) (different from zero; P < 0.05) and an overall time constant of 3.2 ± 1.2 s. Hence, Emax would increase and reach steady state in ∼16 s in response to a step increase in CVP, without any change to ABP or HR, due to the cardiopulmonary baroreflex. Following β-adrenergic receptor blockade, the CVP → Emax transfer function showed a static gain of 0.0007 ± 0.0113 ml(-1) (different from control; P < 0.10). Hence, Emax would change little in steady state in response to a step increase in CVP. Stimulation of the cardiopulmonary baroreflex increases ventricular contractility through β-adrenergic receptor system mediation.

  2. The Effects of Histamine H3 Receptors on Contractile Responses on Rat Gastric Fundus

    Directory of Open Access Journals (Sweden)

    Aşkın Hekimoğlu

    2006-01-01

    Full Text Available The aim of this study is to determine the effects of histamine receptors on the gastrointestinal system smooth muscle contractions and the role of histamine H3 receptors on these effects. İsolated rat gastric fundus preparations were hanged on isolated organ bath and histamine receptor agonist and anthagonists were added to the bath solution and the electrical field stimulation-induced contractile responses were evaluated. In our study groups after blocking one of the histamine receptors H1, H2,H3; contractile responses were observed. Then, other two receptors were blocked one by one or combination of them to observe the changes on the contractile responses given to the electrical stimulation .To blocke histamine receptors pyrilamine (10-6м as H1 receptor blocker, famotidine (10-6м as H2 receptor blocker and thioperamide (10-5м as H3 receptor blocker and various combination of them were used. All groups were treated with H3 receptor anthagonist thioperamide (10-5м and agonist (R-α-methylhistamine (RMHA on 10-8, 10-7, 10-6 ve 10-5 molar concentrations cumulatively to observe its mediator effects on contractile responses. We suggested that (R-α-methylhistamine mediates the inhibition on the contractile effects of rat gastric fundus. This conclusion was supported by these findings: a the selective agonists (RMHA caused a dumping of the contractile effect of acetylcholine; b the effect of (RMHA was prevented by the selective H3 receptor antagonist thioperamide.

  3. Actions of genistein on contractile response of smooth muscle isolated from guinea pig gallbladder

    Institute of Scientific and Technical Information of China (English)

    Ya-Li Luo; Ya-Li Wang; Neng-Lian Li; Tian-Zhen Zheng; Li Zhang; Ya-Li She; Shu-Ming Hu

    2009-01-01

    BACKGROUND: Defective contractile motility of the gallbladder is an important factor for gallstone formation. Estrogen might increase the risk of gallstones and cholecystitis, and estradiol inhibits the contractile activity of isolated strips of guinea pig gallbladder. The potential risks associated with hormone replacement therapy (HRT) include symptomatic gallstones. Phytoestrogen have been used to treat menopause syndromes by replacing traditional estrogen. This experiment aimed to determine the effects of the phytoestrogen genistein on the contractile response of smooth muscle strips isolated from guinea pig gallbladder and its possible mechanism of action. METHODS: Guinea pigs were sacriifced to remove the whole gallbladder. Two or three smooth muscle strips were cut longitudinally. Each strip was suspended in a tissue chamber containing Krebs solution. After 2 hours of equilibration, contractile response indexes were recorded. Different concentrations of genistein were added to the chamber and the contractile responses were measured. Each antagonist was added 2 minutes before genistein to study possible mechanisms. The effect of genistein on calcium-dependent contraction curves and biphasic contraction in calcium-free Krebs solution were measured. RESULTS: Genistein decreased the resting tension dose-dependently, and reduced the mean contractile amplitude and frequency in gallbladder strips. Ranitidine partly inhibited the effect of genistein, but methylene blue, Nω-nitro-L-arginine, and propranolol hydrochloride did not inlfuence this action. Genistein had no signiifcant effects on calcium-dependent contraction. Genistein reduced the ifrst contraction induced by acetylcholine chloride, but did not affect the second contraction caused by CaCl2. CONCLUSIONS: Genistein relaxed smooth muscle isolated from the gallbladder of guinea pigs and this might contribute to the formation of gallstones. The inhibitory action might be related to H2 receptors and

  4. Accessory left atrial diverticulae: contractile properties depicted with 64-slice cine-cardiac CT.

    LENUS (Irish Health Repository)

    Killeen, Ronan P

    2012-02-01

    To assess the contractility of accessory left atrial appendages (LAAs) using multiphasic cardiac CT. We retrospectively analyzed the presence, location, size and contractile properties of accessory LAAs using multiphasic cardiac 64-slice CT in 102 consecutive patients (63 males, 39 females, mean age 57). Multiplanar reformats were used to create image planes in axial oblique, sagittal oblique and coronal oblique planes. For all appendages with an orifice diameter >or= 10 mm, axial and sagittal diameters and appendage volumes were recorded in atrial diastole and systole. Regression analysis was performed to assess which imaging appearances best predicted accessory appendage contractility. Twenty-three (23%) patients demonstrated an accessory LAA, all identified along the anterior LA wall. Dimensions for axial oblique (AOD) and sagittal oblique (SOD) diameters and sagittal oblique length (SOL) were 6.3-19, 3.4-20 and 5-21 mm, respectively. All appendages (>or=10 mm) demonstrated significant contraction during atrial systole (greatest diameter reduction was AOD [3.8 mm, 27%]). Significant correlations were noted between AOD-contraction and AOD (R = 0.57, P < 0.05) and SOD-contraction and AOD, SOD and SOL (R = 0.6, P < 0.05). Mean diverticulum volume in atrial diastole was 468.4 +\\/- 493 mm(3) and in systole was 171.2 +\\/- 122 mm(3), indicating a mean change in volume of 297.2 +\\/- 390 mm(3), P < 0.0001. Stepwise multiple regression analysis revealed SOL to be the strongest independent predictor of appendage contractility (R(2) = 0.86, P < 0.0001) followed by SOD (R(2) = 0.91, P < 0.0001). Accessory LAAs show significant contractile properties on cardiac CT. Those accessory LAAs with a large sagittal height or depth should be evaluated for contractile properties, and if present should be examined for ectopic activity during electrophysiological studies.

  5. FAK Forms a Complex with MEF2 to Couple Biomechanical Signaling to Transcription in Cardiomyocytes.

    Science.gov (United States)

    Cardoso, Alisson Campos; Pereira, Ana Helena Macedo; Ambrosio, Andre Luis Berteli; Consonni, Silvio Roberto; Rocha de Oliveira, Renata; Bajgelman, Marcio Chain; Dias, Sandra Martha Gomes; Franchini, Kleber Gomes

    2016-08-01

    Focal adhesion kinase (FAK) has emerged as a mediator of mechanotransduction in cardiomyocytes, regulating gene expression during hypertrophic remodeling. However, how FAK signaling is relayed onward to the nucleus is unclear. Here, we show that FAK interacts with and regulates myocyte enhancer factor 2 (MEF2), a master cardiac transcriptional regulator. In cardiomyocytes exposed to biomechanical stimulation, FAK accumulates in the nucleus, binds to and upregulates the transcriptional activity of MEF2 through an interaction with the FAK focal adhesion targeting (FAT) domain. In the crystal structure (2.9 Å resolution), FAT binds to a stably folded groove in the MEF2 dimer, known to interact with regulatory cofactors. FAK cooperates with MEF2 to enhance the expression of Jun in cardiomyocytes, an important component of hypertrophic response to mechanical stress. These findings underscore a connection between the mechanotransduction involving FAK and transcriptional regulation by MEF2, with potential relevance to the pathogenesis of cardiac disease. PMID:27427476

  6. Herpesvirus-Mediated Delivery of a Genetically Encoded Fluorescent Ca2+ Sensor to Canine Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    János Prorok

    2009-01-01

    Full Text Available We report the development and application of a pseudorabies virus-based system for delivery of troponeon, a fluorescent Ca2+ sensor to adult canine cardiomyocytes. The efficacy of transduction was assessed by calculating the ratio of fluorescently labelled and nonlabelled cells in cell culture. Interaction of the virus vector with electrophysiological properties of cardiomyocytes was evaluated by the analysis of transient outward current (Ito, kinetics of the intracellular Ca2+ transients, and cell shortening. Functionality of transferred troponeon was verified by FRET analysis. We demonstrated that the transfer efficiency of troponeon to cultured adult cardiac myocytes was virtually 100%. We showed that even after four days neither the amplitude nor the kinetics of the Ito current was significantly changed and no major shifts occurred in parameters of [Ca2+]i transients. Furthermore, we demonstrated that infection of cardiomyocytes with the virus did not affect the morphology, viability, and physiological attributes of cells.

  7. Dataset of integrin-linked kinase protein: Protein interactions in cardiomyocytes identified by mass spectrometry.

    Science.gov (United States)

    Traister, Alexandra; Lu, Mingliang; Coles, John G; Maynes, Jason T

    2016-06-01

    Using hearts from mice overexpressing integrin linked kinase (ILK) behind the cardiac specific promoter αMHC, we have performed immunoprecipitation and mass spectrometry to identify novel ILK protein:protein interactions that regulate cardiomyocyte activity and calcium flux. Integrin linked kinase complexes were captured from mouse heart lysates using a commercial antibody, with subsequent liquid chromatography tandem mass spectral analysis. Interacting partners were identified using the MASCOT server, and important interactions verified using reverse immunoprecipitation and mass spectrometry. All ILK interacting proteins were identified in a non-biased manner, and are stored in the ProteomeXchange Consortium via the PRIDE partner repository (reference ID PRIDE: PXD001053). The functional role of identified ILK interactions in cardiomyocyte function and arrhythmia were subsequently confirmed in human iPSC-cardiomyocytes. PMID:27408918

  8. Hsp60 and p70S6K form a complex in human cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Kroupskaya I. V.

    2011-02-01

    Full Text Available Molecular chaperon Hsp60 and protein kinase p70S6K play an important functional role in the regulation of cardiomyocytes vital function or apoptosis. Aim. To study a possibility of in vivo complex formation between Hsp60 and p70S6K in cardiomyocytes. Methods. Co-immunoprecipitation, Western-blot analysis. Results. We have identified in vivo interaction between molecular chaperone Hsp60 and two isoforms of proteinkinase p70S6K in human myocardium, normal and affected by cardiomyopathy. Conclusions. The results obtained suggest a possible participation of molecular chaperon Hsp60 in regulation of p70S6K activity in stressinduced apoptotic signaling pathway in cardiomyocytes.

  9. Sexual dysfunctions and psychoanalysis.

    Science.gov (United States)

    Levine, E M; Ross, N

    1977-06-01

    The authors examine the major factors involved in recent changes in the social standards and attitudes related to homosexuality. The principal influences investigated include the misconstrued emphasis given to the humanist ideology, which properly stresses the dignity of the individual; the social sciences' relativization of the cultural norms defining homosexuality; the influence of the mass media in disseminating these perspectives and thereby tending to create an acceptable image of homosexuality, and the tendency of all these changes to result in a substantial increase in public acceptance and tolerance of homosexuality. The authors suggest that this trend in public opinion has begun to isolate psychoanalytic knowledge, to reduce its status and acceptability among the public, and to replace it with popular views concerning the meaning of sexual dysfunctions. PMID:869030

  10. Effect of a crude sulfated polysaccharide from Halymenia floresia (Rhodophyta) on gastrointestinal smooth muscle contractility

    OpenAIRE

    José Ronaldo Vasconcelos Graça; Mirna Marques Bezerra; Vilma Lima; José Ariévilo Gurgel Rodrigues; Diego Levi Silveira Monteiro; Ana Luíza Gomes Quinderé; Rodrigo César das Neves Amorim; Regina Célia Monteiro de Paula; Norma Maria Barros Benevides

    2011-01-01

    The aim of this work was to study the effect of Halymenia floresia (Hf) on duodenum contractility, and on experimental protocols of gastric compliance (GC) in rats. Fraction Hf2s exhibited a concentration-dependent myocontractile effect (EC50 12.48 µg/ml), and an inhibitory effect after consecutive washing. The contractile response promoted by Hf2s in the duodenum strips was completely inhibited by verapamil, and the effects were prevented in the presence of Ca2+-free medium. The pretreatment...

  11. Validation of an in vitro contractility assay using canine ventricular myocytes

    International Nuclear Information System (INIS)

    Measurement of cardiac contractility is a logical part of pre-clinical safety assessment in a drug discovery project, particularly if a risk has been identified or is suspected based on the primary- or non-target pharmacology. However, there are limited validated assays available that can be used to screen several compounds in order to identify and eliminate inotropic liability from a chemical series. We have therefore sought to develop an in vitro model with sufficient throughput for this purpose. Dog ventricular myocytes were isolated using a collagenase perfusion technique and placed in a perfused recording chamber on the stage of a microscope at ∼ 36 °C. Myocytes were stimulated to contract at a pacing frequency of 1 Hz and a digital, cell geometry measurement system (IonOptix™) was used to measure sarcomere shortening in single myocytes. After perfusion with vehicle (0.1% DMSO), concentration–effect curves were constructed for each compound in 4–30 myocytes taken from 1 or 2 dog hearts. The validation test-set was 22 negative and 8 positive inotropes, and 21 inactive compounds, as defined by their effect in dog, cynolomolgous monkey or humans. By comparing the outcome of the assay to the known in vivo contractility effects, the assay sensitivity was 81%, specificity was 75%, and accuracy was 78%. With a throughput of 6–8 compounds/week from 1 cell isolation, this assay may be of value to drug discovery projects to screen for direct contractility effects and, if a hazard is identified, help identify inactive compounds. -- Highlights: ► Cardiac contractility is an important physiological function of the heart. ► Assessment of contractility is a logical part of pre-clinical drug safety testing. ► There are limited validated assays that predict effects of compounds on contractility. ► Using dog myocytes, we have developed an in vitro cardiac contractility assay. ► The assay predicted the in vivo contractility with a good level of accuracy.

  12. Appearance of contractile endothelin-B receptors in rat mesenteric arterial segments following organ culture

    DEFF Research Database (Denmark)

    Adner, M; Geary, G G; Edvinsson, L

    1998-01-01

    contraction. The maximum contractile response to S6c was not altered in segments cultured with foetal calf serum or in buffer solution, but was reduced to about 20% of the control value when cultured in glucose-free buffer solution. The contraction to S6c was abolished in segments placed in cold (4 degrees C......) buffer solution. Removal of the endothelium had no effect on the S6c-induced contractions. Arteries cultured at isometric tension (at 2 mN) for 1 day achieved the same contractile response for ETB agonists as resting segments. Pressurized arteries (60 mmHg) did not constrict to S6c when mounted...

  13. Real-Time Visualization and Quantification of Contractile Ring Proteins in Single Living Cells.

    Science.gov (United States)

    Davidson, Reshma; Liu, Yajun; Gerien, Kenneth S; Wu, Jian-Qiu

    2016-01-01

    Single-cell microscopy provides a powerful tool to visualize cellular and subcellular processes in wild-type and mutant cells by observing fluorescently tagged proteins. Here, we describe three simple methods to visualize fission yeast cells: gelatin slides, coverslip-bottom dishes, and tetrad fluorescence microscopy. These imaging methods and data analysis using free software make it possible to quantify protein localization, dynamics, and concentration with high spatial and temporal resolution. In fission yeast, the actomyosin contractile ring is essential for cytokinesis. We use the visualization and quantification of contractile ring proteins as an example to demonstrate how to use these methods.

  14. TO STUDY AND EVALUATE DIASTOLIC DYSFUNCTION IN PATIENTS OF ALCOHOLIC AND NON-ALCOHOLIC CIRRHOSIS

    Directory of Open Access Journals (Sweden)

    Gaurav Sudhir

    2016-04-01

    Full Text Available BACKGROUND Cardiovascular dysfunction is the major component of morbidity in patients of liver cirrhosis and a cardinal prognostic indicator in patients undergoing liver transplantation. The constellation of hyperdynamic circulation, peripheral vasodilation and volume overload alters the systolic and diastolic dysfunction leading to cirrhotic cardiomyopathy (CCM. In this study, we evaluated and compared the diastolic dysfunction among alcoholic and non-alcoholic cirrhotic patients. AIMS 1 To Study the Prevalence of Diastolic Dysfunction in Alcoholic & Non-Alcoholic Cirrhotics and Controls. 2 To Compare the Diastolic functional status between alcoholic and non-alcoholic cirrhosis patients. MATERIALS AND METHODS A cross-sectional case control study was conducted in 100 male cirrhotic patients consisting of alcoholic and non-alcoholic cirrhotic subjects with age matched 50 controls in Pt. JNM Medical College & Dr. BRAM Hospital, Raipur. Left ventricular diastolic dysfunction was assessed using echocardiographic parameters. STATISTICAL ANALYSIS The range, median, standard deviation and statistical significance were calculated. Most of the data is analysed by Student Ttest, Mann Whitney U test, while the data with frequency distribution is analysed by Fisher’s exact. With p value 1. CONCLUSION Our study showed that patients with alcoholic and non-alcoholic cirrhosis have higher occurrence of DD (49% and 46% respectively than controls owing to alterations in the myocardial contractile and relaxation function. It also shows that although DD is a frequent event in cirrhosis, it is usually of mild degree and does not correlate with severity of liver dysfunction. There were no significant differences in diastolic parameters between alcoholic and non-alcoholic cirrhosis concluding that alcohol likely plays a non-significant role in cardiovascular dysfunction in cirrhotics.

  15. Bladder Dysfunction and Vesicoureteral Reflux

    Directory of Open Access Journals (Sweden)

    Ulla Sillén

    2008-01-01

    Full Text Available In this overview the influence of functional bladder disturbances and of its treatment on the resolution of vesicoureteral reflux (VUR in children is discussed. Historically both bladder dysfunction entities, the overactive bladder (OAB and the dysfunctional voiding (DV, have been described in conjunction with VUR. Treatment of the dysfunction was also considered to influence spontaneous resolution in a positive way. During the last decades, however, papers have been published which could not support these results. Regarding the OAB, a prospective study with treatment of the bladder overactivity with anticholinergics, did not influence spontaneous resolution rate in children with a dysfunction including also the voiding phase, DV and DES (dysfunctional elimination syndrome, most studies indicate a negative influence on the resolution rate of VUR in children, both before and after the age for bladder control, both with and without treatment. However, a couple of uncontrolled studies indicate that there is a high short-term resolution rate after treatment with flow biofeedback. It should be emphasized that the voiding phase dysfunctions (DV and DES are more severe than the genuine filling phase dysfunction (OAB, with an increased frequency of UTI and renal damage in the former groups. To be able to answer the question if treatment of bladder dysfunction influence the resolution rate of VUR in children, randomized controlled studies must be performed.

  16. Mitochondrial Dysfunction and Psychiatric Disorders

    OpenAIRE

    Shaw-Hwa Jou; Nan-Yin Chiu; Chin-San Liu

    2009-01-01

    Mitochondria are intracellular organelles crucial in the production of cellular energy.Mitochondrial diseases may result from malfunctions in this biochemical cascade. Severalinvestigators have proposed that mitochondrial dysfunction is related to the pathophysiologyof bipolar disorder (BD), major depressive disorder (MDD) and schizophrenia (SZ). Theauthors reviewed recent study findings and tried to delineate the current understanding of thecorrelation between mitochondrial dysfunction and p...

  17. β-Hydroxybutyrate elevation as a compensatory response against oxidative stress in cardiomyocytes.

    Science.gov (United States)

    Nagao, Manabu; Toh, Ryuji; Irino, Yasuhiro; Mori, Takeshige; Nakajima, Hideto; Hara, Tetsuya; Honjo, Tomoyuki; Satomi-Kobayashi, Seimi; Shinke, Toshiro; Tanaka, Hidekazu; Ishida, Tatsuro; Hirata, Ken-Ichi

    2016-07-01

    Recent studies have shown that the ketone body β-hydroxybutyrate (βOHB) acts not only as a carrier of energy but also as a signaling molecule that has a role in diverse cellular functions. Circulating levels of ketone bodies have been previously reported to be increased in patients with congestive heart failure (HF). In this study, we investigated regulatory mechanism and pathophysiological role of βOHB in HF. First, we revealed that βOHB level was elevated in failing hearts, but not in blood, using pressure-overloaded mice. We also measured cellular βOHB levels in both cardiomyocytes and non-cardiomyocytes stimulated with or without H2O2 and revealed that increased myocardial βOHB was derived from cardiomyocytes but not non-cardiomyocytes under pathological states. Next, we sought to elucidate the mechanisms of myocardial βOHB elevation and its implication under pathological states. The gene and protein expression levels of CoA transferase (SCOT), a key enzyme involved in ketone body oxidation, was decreased in failing hearts. In cardiomyocytes, H2O2 stimulation caused βOHB accumulation concomitantly with SCOT downregulation, implying that the accumulation of myocardial βOHB occurs because of the decline in its utilization. Finally, we checked the effects of βOHB on cardiomyocytes under oxidative stress. We found that βOHB induced FOXO3a, an oxidative stress resistance gene, and its target enzyme, SOD2 and catalase. Consequently, βOHB attenuated reactive oxygen species production and alleviated apoptosis induced by oxidative stress. It has been reported that hyperadrenergic state in HF boost lipolysis and result in elevation of circulating free fatty acids, which can lead hepatic ketogenesis for energy metabolism alteration. The present findings suggest that the accumulation of βOHB also occurs as a compensatory response against oxidative stress in failing hearts. PMID:27216458

  18. Examination of the Effects of Heterogeneous Organization of RyR Clusters, Myofibrils and Mitochondria on Ca2+ Release Patterns in Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Vijay Rajagopal

    2015-09-01

    Full Text Available Spatio-temporal dynamics of intracellular calcium, [Ca2+]i, regulate the contractile function of cardiac muscle cells. Measuring [Ca2+]i flux is central to the study of mechanisms that underlie both normal cardiac function and calcium-dependent etiologies in heart disease. However, current imaging techniques are limited in the spatial resolution to which changes in [Ca2+]i can be detected. Using spatial point process statistics techniques we developed a novel method to simulate the spatial distribution of RyR clusters, which act as the major mediators of contractile Ca2+ release, upon a physiologically-realistic cellular landscape composed of tightly-packed mitochondria and myofibrils. We applied this method to computationally combine confocal-scale (~ 200 nm data of RyR clusters with 3D electron microscopy data (~ 30 nm of myofibrils and mitochondria, both collected from adult rat left ventricular myocytes. Using this hybrid-scale spatial model, we simulated reaction-diffusion of [Ca2+]i during the rising phase of the transient (first 30 ms after initiation. At 30 ms, the average peak of the simulated [Ca2+]i transient and of the simulated fluorescence intensity signal, F/F0, reached values similar to that found in the literature ([Ca2+]i ≈1 μM; F/F0≈5.5. However, our model predicted the variation in [Ca2+]i to be between 0.3 and 12.7 μM (~3 to 100 fold from resting value of 0.1 μM and the corresponding F/F0 signal ranging from 3 to 9.5. We demonstrate in this study that: (i heterogeneities in the [Ca2+]i transient are due not only to heterogeneous distribution and clustering of mitochondria; (ii but also to heterogeneous local densities of RyR clusters. Further, we show that: (iii these structure-induced heterogeneities in [Ca2+]i can appear in line scan data. Finally, using our unique method for generating RyR cluster distributions, we demonstrate the robustness in the [Ca2+]i transient to differences in RyR cluster distributions

  19. Examination of the Effects of Heterogeneous Organization of RyR Clusters, Myofibrils and Mitochondria on Ca2+ Release Patterns in Cardiomyocytes.

    Science.gov (United States)

    Rajagopal, Vijay; Bass, Gregory; Walker, Cameron G; Crossman, David J; Petzer, Amorita; Hickey, Anthony; Siekmann, Ivo; Hoshijima, Masahiko; Ellisman, Mark H; Crampin, Edmund J; Soeller, Christian

    2015-09-01

    Spatio-temporal dynamics of intracellular calcium, [Ca2+]i, regulate the contractile function of cardiac muscle cells. Measuring [Ca2+]i flux is central to the study of mechanisms that underlie both normal cardiac function and calcium-dependent etiologies in heart disease. However, current imaging techniques are limited in the spatial resolution to which changes in [Ca2+]i can be detected. Using spatial point process statistics techniques we developed a novel method to simulate the spatial distribution of RyR clusters, which act as the major mediators of contractile Ca2+ release, upon a physiologically-realistic cellular landscape composed of tightly-packed mitochondria and myofibrils. We applied this method to computationally combine confocal-scale (~ 200 nm) data of RyR clusters with 3D electron microscopy data (~ 30 nm) of myofibrils and mitochondria, both collected from adult rat left ventricular myocytes. Using this hybrid-scale spatial model, we simulated reaction-diffusion of [Ca2+]i during the rising phase of the transient (first 30 ms after initiation). At 30 ms, the average peak of the simulated [Ca2+]i transient and of the simulated fluorescence intensity signal, F/F0, reached values similar to that found in the literature ([Ca2+]i ≈1 μM; F/F0≈5.5). However, our model predicted the variation in [Ca2+]i to be between 0.3 and 12.7 μM (~3 to 100 fold from resting value of 0.1 μM) and the corresponding F/F0 signal ranging from 3 to 9.5. We demonstrate in this study that: (i) heterogeneities in the [Ca2+]i transient are due not only to heterogeneous distribution and clustering of mitochondria; (ii) but also to heterogeneous local densities of RyR clusters. Further, we show that: (iii) these structure-induced heterogeneities in [Ca2+]i can appear in line scan data. Finally, using our unique method for generating RyR cluster distributions, we demonstrate the robustness in the [Ca2+]i transient to differences in RyR cluster distributions measured between

  20. Muscle dysfunction in cancer patients

    DEFF Research Database (Denmark)

    Christensen, Jesper Frank; Jones, L W; Andersen, J L;

    2014-01-01

    implications of muscle dysfunction in cancer patients. The efficacy of exercise training to prevent and/or mitigate cancer-related muscle dysfunction is also discussed. DESIGN: We identified 194 studies examining muscular outcomes in cancer patients by searching PubMed and EMBASE databases. RESULTS: Muscle...... dysfunction is evident across all stages of the cancer trajectory. The causes of cancer-related muscle dysfunction are complex, but may involve a wide range of tumor-, therapy- and/or lifestyle-related factors, depending on the clinical setting of the individual patient. The main importance of muscle...... dysfunction in cancer patients lies in the correlation to vital clinical end points such as cancer-specific and all-cause mortality, therapy complications and quality of life (QoL). Such associations strongly emphasize the need for effective therapeutic countermeasures to be developed and implemented...

  1. Influence of muscle temperature on the contractile properties of the quadriceps muscle in humans with spinal cord injury

    NARCIS (Netherlands)

    Gerrits, H L; de Haan, A; Hopman, M T; van der Woude, L H; Sargeant, A J

    2000-01-01

    Low muscle temperature in paralysed muscles of individuals with spinal cord injury may affect the contractile properties of these muscles. The present study was therefore undertaken to assess the effects of increased muscle temperature on the isometric contractile properties of electrically stimulat

  2. Ultrastructural maturation of human bone marrow mesenchymal stem cells-derived cardiomyocytes under alternative induction of 5-azacytidine.

    Science.gov (United States)

    Piryaei, Abbas; Soleimani, Masoud; Heidari, Mohammad Hassan; Saheli, Mona; Rohani, Razieh; Almasieh, Mohammadali

    2015-05-01

    Adult cardiomyocytes lack the ability to proliferate and are unable to repair damaged heart tissue, therefore differentiation of stem cells to cardiomyocytes represents an exceptional opportunity to study cardiomyocytes in vitro and potentially provides a valuable source for replacing damaged tissue. However, characteristic maturity of the in vitro differentiated cardiomyocytes and methods to achieve it are yet to be optimized. In this study, differentiation of human bone marrow-mesenchymal stem cells (hBM-MSCs) into cardiomyocytes is accomplished and the process investigated ultrastructurally. The hBM-MSCs were alternatively treated with 5 μM of 5-azacytidine (5-aza) for 8 weeks resulting in differentiation to cardiomyocytes. Expressions of cardiomyocyte-specific genes [cardiac α-actinin, cardiac β-myosin heavy chain (MHC) and connexin-43] and proteins (cardiac α-actinin, cardiac troponin and connexin-43) were confirmed in a time-dependent manner from the first to the fifth weeks post-induction. Ultrastructural maturation of hBM-MSCs-derived cardiomyocyte (MSCs-CM) corresponded with increase in number and organization of myofilaments in cells over time. Starting from week five, organized myofibrils along with developing sarcomeres were detectable. Later on, MSCs-CM were characterized by the presence of sarcoplasmic reticulum, T-tubules and diads as cardiomyocytes connected to each other by intercalated disc-like structures. Here, we showed the potential of hBM-MSCs as a source for the production of cardiomyocytes and confirmed mature ultrastructural characteristics of these cells using our alternative incubation method. PMID:25573851

  3. Inducible Cardiomyocyte-Specific Gene Disruption Directed by the Rat Tnnt2 Promoter in the Mouse

    OpenAIRE

    Wu, Bingruo; Wang, Yidong; Cheng, Hsiu-Ling; Hang, Calvin T.; Pu, William T.; Chang, Ching-Pin; Zhou, Bin

    2010-01-01

    We developed a conditional and inducible gene knockout methodology that allows effective gene deletion in mouse cardiomyocytes. This transgenic mouse line was generated by co-injection of two transgenes, a “reverse” tetracycline-controlled transactivator (rtTA) directed by a rat cardiac troponin T (Tnnt2) promoter and a Cre recombinase driven by a tetracycline-responsive promoter (TetO). Here, Tnnt2-rtTA activated TetO-Cre expression takes place in cardiomyocytes following doxycycline treatme...

  4. miR-218 Involvement in Cardiomyocyte Hypertrophy Is Likely through Targeting REST

    OpenAIRE

    Jing-Jing Liu; Cui-Mei Zhao; Zhi-Gang Li; Yu-Mei Wang; Wei Miao; Xiu-Juan Wu; Wen-Jing Wang; Chang Liu; Duo Wang; Kang Wang; Li Li; Lu-Ying Peng

    2016-01-01

    MicroRNAs (miRNAs) have been identified as key players in cardiomyocyte hypertrophy, which is associated with significant risks of heart failure. However, many microRNAs are still not recognized for their functions in pathophysiological processes. In this study, we evaluated effects of miR-218 in cardiomyocyte hypertrophy using both in vitro and in vivo models. We found that miR-218 was evidently downregulated in a transverse aortic constriction (TAC) mouse model. Overexpression of miR-218 is...

  5. Value of 4D-strain imaging echocardiography in detecting left ventricular systolic dysfunction in patients with aortic stenosis

    Institute of Scientific and Technical Information of China (English)

    ZHENG Zhi-chao; LI He-zhi; LI Chang-mao; CHEN Ou-di; FEI Hong-wen; LIN Qiong-wen

    2016-01-01

    Background The myocyte dysfunction may be present in aortic stenosis (AS) patients with preserved left ventricular ejection fraction (LVEF).Early aortic valve replacement (AVR) can reverse the LV hypertrophy and improve LV systolic performance and clinical outcome.Strain imaging has demonstrated to be the most appropriate method to evaluate LV myocardial contractility.However,4D-strain imaging echocardiography for the detection of subclinical left ventricular dysfunction in AS patients with preserved LVEF is seldom studied.Methods We prospectively enrolled 30 consecutive moderate to severe AS patients with preserved LVEF,and 30 healthy controls.Conventional echocardiography and 4D-strain imaging echocardiography were undergone in two groups.The 4D strain echocardiographic analyses were undertaken by using 4D Auto LVQ software.Results Compared with the healthy controls,the moderate to severe AS patients with preserved LVEF had significantly decreased global radial strain (GRS),global longitudinal strain (GLS),global area strain (GAS) and 4D strain (P < 0.05),had significantly increased left ventricular end-diastolic volume index (LVEDVI) and left ventricular mass index (LVMI) (P < 0.05),and had lower global circumferential strain (GCS) (P > 0.05).Conclusions Impaired LV myocardial contractility exists in moderate to severe AS patients,although LVEF is preserved.4D-strain imaging echocardiography can detect early left ventricular dysfunction in AS patients with preserved LVEF.

  6. Top-Down Targeted Proteomics Reveals Decrease in Myosin Regulatory Light-Chain Phosphorylation That Contributes to Sarcopenic Muscle Dysfunction.

    Science.gov (United States)

    Gregorich, Zachery R; Peng, Ying; Cai, Wenxuan; Jin, Yutong; Wei, Liming; Chen, Albert J; McKiernan, Susan H; Aiken, Judd M; Moss, Richard L; Diffee, Gary M; Ge, Ying

    2016-08-01

    Sarcopenia, the loss of skeletal muscle mass and function with advancing age, is a significant cause of disability and loss of independence in the elderly and thus, represents a formidable challenge for the aging population. Nevertheless, the molecular mechanism(s) underlying sarcopenia-associated muscle dysfunction remain poorly understood. In this study, we employed an integrated approach combining top-down targeted proteomics with mechanical measurements to dissect the molecular mechanism(s) in age-related muscle dysfunction. Top-down targeted proteomic analysis uncovered a progressive age-related decline in the phosphorylation of myosin regulatory light chain (RLC), a critical protein involved in the modulation of muscle contractility, in the skeletal muscle of aging rats. Top-down tandem mass spectrometry analysis identified a previously unreported bis-phosphorylated proteoform of fast skeletal RLC and localized the sites of decreasing phosphorylation to Ser14/15. Of these sites, Ser14 phosphorylation represents a previously unidentified site of phosphorylation in RLC from fast-twitch skeletal muscle. Subsequent mechanical analysis of single fast-twitch fibers isolated from the muscles of rats of different ages revealed that the observed decline in RLC phosphorylation can account for age-related decreases in the contractile properties of sarcopenic fast-twitch muscles. These results strongly support a role for decreasing RLC phosphorylation in sarcopenia-associated muscle dysfunction and suggest that therapeutic modulation of RLC phosphorylation may represent a new avenue for the treatment of sarcopenia. PMID:27362462

  7. Influence of bladder outlet obstruction and detrusor contractility on residual urine in patients with benign prostatic hyperplasia

    Institute of Scientific and Technical Information of China (English)

    张鹏; 武治津; 高居忠

    2003-01-01

    Objective To study the relationship between the degree of bladder outlet obstruction (BOO), detrusor contractility and residual urine in patients suffering from benign prostatic hyperplasia (BPH).Methods In 181 patients with BPH, degree of BOO, detrusor contractility, residual urine caculated from cathetering combined with the difference between the filling and the voiding were recorded and analysized statistically using urodynamic technique.Results Residual urine increased when the detusor contractility was weakened (F=12.134, P=0.001). In patients wih severe BOO, there was no significant difference in residual urine (F=2.386, P=0.071).Conclusions Increased residual urine is mainly resulted from decreased detrusor contractility. BOO has no significant influence on residual urine. Some patients with normal or weakened detrusor contractility may have more residual urine

  8. Human mesenchymal stem cells reprogram adult cardiomyocytes toward a progenitor-like state through partial cell fusion and mitochondria transfer : Cell fusion-mediated cardiomyocyte reprogramming.

    OpenAIRE

    Acquistapace, Adrien; Bru, Thierry; Lesault, Pierre-François; Figeac, Florence; Coudert, Amélie,; Le Coz, Olivier; Christov, Christo; Baudin, Xavier; Auber, Fréderic; Yiou, René; Dubois-Randé, Jean-Luc; Rodriguez, Anne-Marie

    2011-01-01

    International audience Because stem cells are often found to improve repair tissue including heart without evidence of engraftment or differentiation, mechanisms underlying wound healing are still elusive. Several studies have reported that stem cells can fuse with cardiomyocytes either by permanent or partial cell fusion processes. However, the respective physiological impact of these two processes remains unknown in part because of the lack of knowledge of the resulting hybrid cells. To ...

  9. Mitochondria-Targeted Antioxidant Prevents Cardiac Dysfunction Induced by Tafazzin Gene Knockdown in Cardiac Myocytes

    Directory of Open Access Journals (Sweden)

    Quan He

    2014-01-01

    Full Text Available Tafazzin, a mitochondrial acyltransferase, plays an important role in cardiolipin side chain remodeling. Previous studies have shown that dysfunction of tafazzin reduces cardiolipin content, impairs mitochondrial function, and causes dilated cardiomyopathy in Barth syndrome. Reactive oxygen species (ROS have been implicated in the development of cardiomyopathy and are also the obligated byproducts of mitochondria. We hypothesized that tafazzin knockdown increases ROS production from mitochondria, and a mitochondria-targeted antioxidant prevents tafazzin knockdown induced mitochondrial and cardiac dysfunction. We employed cardiac myocytes transduced with an adenovirus containing tafazzin shRNA as a model to investigate the effects of the mitochondrial antioxidant, mito-Tempo. Knocking down tafazzin decreased steady state levels of cardiolipin and increased mitochondrial ROS. Treatment of cardiac myocytes with mito-Tempo normalized tafazzin knockdown enhanced mitochondrial ROS production and cellular ATP decline. Mito-Tempo also significantly abrogated tafazzin knockdown induced cardiac hypertrophy, contractile dysfunction, and cell death. We conclude that mitochondria-targeted antioxidant prevents cardiac dysfunction induced by tafazzin gene knockdown in cardiac myocytes and suggest mito-Tempo as a potential therapeutic for Barth syndrome and other dilated cardiomyopathies resulting from mitochondrial oxidative stress.

  10. Therapeutic Approach in the Improvement of Endothelial Dysfunction: The Current State of the Art

    Directory of Open Access Journals (Sweden)

    Miroslav Radenković

    2013-01-01

    Full Text Available The endothelium has a central role in the regulation of blood flow through continuous modulation of vascular tone. This is primarily accomplished by balanced release of endothelial relaxing and contractile factors. The healthy endothelial cells are essential for maintenance of vascular homeostasis involving antioxidant, anti-inflammatory, pro-fibrinolytic, anti-adhesive, or anticoagulant effects. Oppositely, endothelial dysfunction is primarily characterized by impaired regulation of vascular tone as a result of reduced endothelial nitric oxide (NO synthase activity, lack of cofactors for NO synthesis, attenuated NO release, or increased NO degradation. So far, the pharmacological approach in improving/reversal of endothelial dysfunction was shown to be beneficial in clinical trials that have investigated actions of different cardiovascular drugs. The aim of this paper was to summarize some of the latest clinical findings related to therapeutic possibilities for improving endothelial dysfunction in different pathological conditions. In the majority of presented clinical investigations, the assessment of improvement or reversal of endothelial dysfunction was performed through the flow-mediated dilatation measurement, and in some of those endothelial progenitor cells’ count was used for the same purpose. Still, given the fast and continuous development of this field, the evidence acquisition included the MEDLINE data base screening and the selection of articles published between 2010 and 2012.

  11. Association between aortic stenosis severity and contractile reserve measured by two-dimensional strain under low-dose dobutamine testing

    Directory of Open Access Journals (Sweden)

    Banović Marko

    2013-01-01

    Full Text Available Background/Aim. Early detection of left ventricle (LV systolic dysfunction could be a clue for surgical treatment in patients with significant aortic stenosis (AS. Therefore, we evaluated LV peak of global longitudinal strain (PGLS using speckle tracking imaging at rest and during low-dose dobutamine infusion in asymptomatic patients with moderate and severe AS and preserved LV ejection fraction (EF. Methods. All the patients underwent coronary angiography and had no obstructive coronary disease (defined as having no stenosis greater than 50% in diameter. The patients were divided into two groups: above and below median of 0.785 cm2 aortic valve area (AVA. PGLS was measured from acquired apical 4-chamber and 2-chamber cine loops using a EchoPac PC-workstation at rest and during 5 μg/kg/min, 10 μg/kg/min, and 20 μg/kg/min dobutamine infusion, respectively. The global strain was the average of segment strains from the apical views. Results: A total of 62 patients with moderate and severe AS (AVA median reached the statistical significance (- 8.71 ± 2.68% vs -11.93 ± 3.74%, p = 0.002. In addition, PGLS increase was also significant in 4-chamber view in the patients with AVA above median, but only when comparing baseline to peak 20 μg/kg/min (-10.72 ± 3.07% vs -13.14 ± 4.79%; p = 0.034. Conversely, in both groups the increase of PGLS in 2-chamber view did not reach significance. Conclusion. Two-dimensional strain speckle tracking analysis of myocardial deformation with measurement of peak systolic strain during dobutamine infusion is a feasible and accurate method to determine myocardial longitudinal systolic function and contractile reserve and may contribute to clinical decision making in patients with significant AS.

  12. Insulin Preconditioning Elevates p-Akt and Cardiac Contractility after Reperfusion in the Isolated Ischemic Rat Heart

    Directory of Open Access Journals (Sweden)

    Tamaki Sato

    2014-01-01

    Full Text Available Insulin induces cardioprotection partly via an antiapoptotic effect. However, the optimal timing of insulin administration for the best quality cardioprotection remains unclear. We tested the hypothesis that insulin administered prior to ischemia provides better cardioprotection than insulin administration after ischemia. Isolated rat hearts were prepared using Langendorff method and divided into three groups. The Pre-Ins group (Pre-Ins received 0.5 U/L insulin prior to 15 min no-flow ischemia for 20 min followed by 20 min of reperfusion. The Post-Ins group (Post-Ins received 0.5 U/L insulin during the reperfusion period only. The control group (Control was perfused with KH buffer throughout. The maximum of left ventricular derivative of pressure development (dP/dt(max was recorded continuously. Measurements of TNF-α and p-Akt in each time point were assayed by ELISA. After reperfusion, dP/dt(max in Pre-Ins was elevated, compared with Post-Ins at 10 minutes after reperfusion and Control at all-time points. TNF-α levels at 5 minutes after reperfusion in the Pre-Ins were lower than the others. After 5 minutes of reperfusion, p-Akt was elevated in Pre-Ins compared with the other groups. Insulin administration prior to ischemia provides better cardioprotection than insulin administration only at reperfusion. TNF-α suppression is possibly mediated via p-Akt leading to a reduction in contractile myocardial dysfunction.

  13. Reproducibility of contractile properties of the human paralysed and non-paralysed quadriceps muscle.

    NARCIS (Netherlands)

    Gerrits, H.L.; Hopman, M.T.E.; Sargeant, A.J.; Haan, A. de

    2001-01-01

    This study assessed the reproducibility of electrically evoked, isometric quadriceps contractile properties in eight people with spinal cord injury (SCI) and eight able-bodied (AB) individuals. Over all, the pooled coefficients of variation (CVps) in the SCI group were significantly lower (ranging f

  14. Influence of Contractility on Myocardial Ultrasonic Integrated Backscatter and Cyclic Variation in Integrated Backscatter

    Institute of Scientific and Technical Information of China (English)

    毕小军; 邓又斌; 潘敏; 杨好意; 向慧娟; 常青; 黎春雷

    2002-01-01

    Summary: To evaluate the effects of left ventricular contractility on the changes of average image intensity (AII) of the myocardial integrated backscatter (IB) and cyclic variation in IB (CVIB), 7 adult mongrel dogs were studied. The magnitude of AII and CVIB were measured from myocardial IB carves before and after dobutamine or propranolol infusion. Dobutamine or propranolol did not affect the magnitude of AII (13.8±0. 7 vs 14.7±0. 5, P>0. 05 or 14.3±0.5 vs 14.2±0. 4, P>0. 05). However, dobutamine produced a significant increase in the magnitude of CVIB (6.8±0.3 vs 9.5 ± 0. 6, P<0. 001) and propranolol induced significant decrease in the magnitude of CVIB (7.1±0. 2 vs 5.2±0. 3, P<0. 001). The changes of the magnitude of AII and CVIB in the myocardium have been demonstrated to reflect different myocardial physiological and pathological changes respectively. The alteration of contractility did not affect the magnitude of AII but induced significant change in CVIB. The increase of left ventricular contractility resulted in a significant rise of the magnitude of CVIB and the decrease of left ventricular contractility resulted in a significant fall of the magnitude of CVIB.

  15. Protective Effect of Capsicum Frutescens on Contractile Reactivity of Streptozotocin-Diabetic Rats

    Directory of Open Access Journals (Sweden)

    F. Roghani-Dehkordi

    2005-07-01

    Full Text Available Introduction & Objective : Considering the higher incidence of atherosclerosis and cardiovascular disorders in diabetes mellitus, this study was conducted to evaluate the effect of oral one-month administration of red pepper (Capsicum frutescens on the contractile reactivity of isolated aorta in diabetic rats. Materials & Methods : For this purpose, male Wistar rats(n=32 were randomly divided into control, pepper-treated control, diabetic, and pepper-treated diabetic groups. For induction of diabetes, streptozotcin (STZ was intraperitoneally administered (60 mg/Kg. Pepper-treated groups received pepper mixed with standard pelleted food at a weight ratio of 1/15. After one month, contractile reactivity of aortic rings to KCl and noreadrenaline was determined using isolated tissue setup. Results : Serum glucose level showed a significant increase in diabetic group at 2nd and 4th weeks (P<0.001, while this increase was less marked in pepper-treated diabetic group at the 2nd week (P<0.05. In addition, the latter group showed a lower contraction to KCl (P<0.05 and noreadrenaline (P<0.05 as compared to diabetic group. Meanwhile, there was no significant difference between control and pepper-treated control groups regarding contractile reactivity. Conclusion : It can be concluded that oral administration of pepper for one month could attenuate the contractile responsiveness of the vascular system and may prevent the development of hypertension in diabetic rats.

  16. Redundant mechanisms recruit actin into the contractile ring in silkworm spermatocytes.

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2008-09-01

    Full Text Available Cytokinesis is powered by the contraction of actomyosin filaments within the newly assembled contractile ring. Microtubules are a spindle component that is essential for the induction of cytokinesis. This induction could use central spindle and/or astral microtubules to stimulate cortical contraction around the spindle equator (equatorial stimulation. Alternatively, or in addition, induction could rely on astral microtubules to relax the polar cortex (polar relaxation. To investigate the relationship between microtubules, cortical stiffness, and contractile ring assembly, we used different configurations of microtubules to manipulate the distribution of actin in living silkworm spermatocytes. Mechanically repositioned, noninterdigitating microtubules can induce redistribution of actin at any region of the cortex by locally excluding cortical actin filaments. This cortical flow of actin promotes regional relaxation while increasing tension elsewhere (normally at the equatorial cortex. In contrast, repositioned interdigitating microtubule bundles use a novel mechanism to induce local stimulation of contractility anywhere within the cortex; at the antiparallel plus ends of central spindle microtubules, actin aggregates are rapidly assembled de novo and transported laterally to the equatorial cortex. Relaxation depends on microtubule dynamics but not on RhoA activity, whereas stimulation depends on RhoA activity but is largely independent of microtubule dynamics. We conclude that polar relaxation and equatorial stimulation mechanisms redundantly supply actin for contractile ring assembly, thus increasing the fidelity of cleavage.

  17. Effects of C-type natriuretic peptide on rat cardiac contractility

    OpenAIRE

    Brusq, Jean-Marie; Mayoux, Eric; Guigui, Laurent; Kirilovsky, Jorge

    1999-01-01

    Natriuretic peptide receptors have been found in different heart preparations. However, the role of natriuretic peptides in the regulation of cardiac contractility remains largely elusive and was, therefore, studied here.The rate of relaxation of electrically stimulated, isolated rat papillary muscles was enhanced (114.4±1.4%, P

  18. Cellular contractility and extracellular matrix stiffness regulate matrix metalloproteinase activity in pancreatic cancer cells.

    Science.gov (United States)

    Haage, Amanda; Schneider, Ian C

    2014-08-01

    The pathogenesis of cancer is often driven by local invasion and metastasis. Recently, mechanical properties of the tumor microenvironment have been identified as potent regulators of invasion and metastasis, while matrix metalloproteinases (MMPs) are classically known as significant enhancers of cancer cell migration and invasion. Here we have been able to sensitively measure MMP activity changes in response to specific extracellular matrix (ECM) environments and cell contractility states. Cells of a pancreatic cancer cell line, Panc-1, up-regulate MMP activities between 3- and 10-fold with increased cell contractility. Conversely, they down-regulate MMP activities when contractility is blocked to levels seen with pan-MMP activity inhibitors. Similar, albeit attenuated, responses are seen in other pancreatic cancer cell lines, BxPC-3 and AsPC-1. In addition, MMP activity was modulated by substrate stiffness, collagen gel concentration, and the degree of collagen cross-linking, when cells were plated on collagen gels ranging from 0.5 to 5 mg/ml that span the physiological range of substrate stiffness (50-2000 Pa). Panc-1 cells showed enhanced MMP activity on stiffer substrates, whereas BxPC-3 and AsPC-1 cells showed diminished MMP activity. In addition, eliminating heparan sulfate proteoglycans using heparinase completely abrogated the mechanical induction of MMP activity. These results demonstrate the first functional link between MMP activity, contractility, and ECM stiffness and provide an explanation as to why stiffer environments result in enhanced cell migration and invasion.

  19. Effect of pinaverium bromide on stress-induced colonic smooth muscle contractility disorder in rats

    OpenAIRE

    Dai, Yun; Liu, Jian-Xiang; Li, Jun-Xia; Xu, Yun-Feng

    2003-01-01

    AIM: To investigate the effect of pinaverium bromide, a L-type calcium channel blocker with selectivity for the gastrointestinal tract on contractile activity of colonic circular smooth muscle in normal or cold-restraint stressed rats and its possible mechanism.

  20. Impaired pulmonary artery contractile responses in a rat model of microgravity: role of nitric oxide

    Science.gov (United States)

    Nyhan, Daniel; Kim, Soonyul; Dunbar, Stacey; Li, Dechun; Shoukas, Artin; Berkowitz, Dan E.

    2002-01-01

    Vascular contractile hyporesponsiveness is an important mechanism underlying orthostatic intolerance after microgravity. Baroreceptor reflexes can modulate both pulmonary resistance and capacitance function and thus cardiac output. We hypothesized, therefore, that pulmonary vasoreactivity is impaired in the hindlimb-unweighted (HLU) rat model of microgravity. Pulmonary artery (PA) contractile responses to phenylephrine (PE) and U-46619 (U4) were significantly decreased in the PAs from HLU vs. control (C) animals. N(G)-nitro-L-arginine methyl ester (10(-5) M) enhanced the contractile responses in the PA rings from both C and HLU animals and completely abolished the differential responses to PE and U4 in HLU vs. C animals. Vasorelaxant responses to ACh were significantly enhanced in PA rings from HLU rats compared with C. Moreover, vasorelaxant responses to sodium nitroprusside were also significantly enhanced. Endothelial nitric oxide synthase (eNOS) and soluble guanlyl cyclase expression were significantly enhanced in PA and lung tissue from HLU rats. In marked contrast, the expression of inducible nitric oxide synthase was unchanged in lung tissue. These data support the hypothesis that vascular contractile responsiveness is attenuated in PAs from HLU rats and that this hyporesponsiveness is due at least in part to increased nitric oxide synthase activity resulting from enhanced eNOS expression. These findings may have important implications for blood volume distribution and attenuated stroke volume responses to orthostatic stress after microgravity exposure.

  1. Hydrogen ion changes and contractile behavior in the perfused rat heart

    NARCIS (Netherlands)

    Cingolani, H.E.; Maas, A.H.J.; Zimmerman, A.N.E.; Meijler, F.L.

    1975-01-01

    The effect of acid-base alterations was analyzed using isolated rat hearts perfused at constant coronary perfusion pressure, and stimulated to contract at constant rate. The amount of shortening in the major axis and its derivative were measured to assess myocardial contractility. Both the 'respirat

  2. Contractile properties of the quadriceps muscle in individuals with spinal cord injury

    NARCIS (Netherlands)

    Gerrits, H L; De Haan, A; Hopman, M T; van Der Woude, L H; Jones, D A; Sargeant, A J

    1999-01-01

    Selected contractile properties and fatigability of the quadriceps muscle were studied in seven spinal cord-injured (SCI) and 13 able-bodied control (control) individuals. The SCI muscles demonstrated faster rates of contraction and relaxation than did control muscles and extremely large force oscil

  3. Contractile speed and fatigue of adductor pollicis muscle in multiple sclerosis

    NARCIS (Netherlands)

    de Ruiter, C J; Jongen, P J; van der Woude, L H; de Haan, A

    2001-01-01

    The purpose of the study was to investigate differences in contractile speed, force, and fatigability of the adductor pollicis muscle between 12 patients with multiple sclerosis (MS) and 8 sedentary control subjects matched for age and gender. There were no differences between the patients with MS a

  4. Consecutive bouts of diverse contractile activity alter acute responses in human skeletal muscle

    DEFF Research Database (Denmark)

    Coffey, Vernon G; Pilegaard, Henriette; Garnham, Andrew P;

    2009-01-01

    -activated receptor gamma coactivator-1alpha mRNA did not reveal an order effect. We conclude that acute responses to diverse bouts of contractile activity are modified by the exercise order. Moreover, undertaking divergent exercise in close proximity influences the acute molecular profile and likely exacerbates...

  5. Four days of muscle disuse impairs single fiber contractile function in young and old healthy men

    DEFF Research Database (Denmark)

    Hvid, Lars G; Suetta, Charlotte; Aagaard, Per;

    2013-01-01

    The purpose of the study was to investigate the effects of 4days of disuse (knee brace) on contractile function of isolated vastus lateralis fibers (n=486) from 11 young (24.3±0.9yrs) and 11 old (67.2±1.0yrs) healthy men having comparable levels of physical activity. Prior to disuse single fiber...

  6. In vivo visualization and quantification of collecting lymphatic vessel contractility using near-infrared imaging

    Science.gov (United States)

    Chong, Chloé; Scholkmann, Felix; Bachmann, Samia B.; Luciani, Paola; Leroux, Jean-Christophe; Detmar, Michael; Proulx, Steven T.

    2016-01-01

    Techniques to image lymphatic vessel function in either animal models or in the clinic are limited. In particular, imaging methods that can provide robust outcome measures for collecting lymphatic vessel function are sorely needed. In this study, we aimed to develop a method to visualize and quantify collecting lymphatic vessel function in mice, and to establish an in vivo system for evaluation of contractile agonists and antagonists using near-infrared fluorescence imaging. The flank collecting lymphatic vessel in mice was exposed using a surgical technique and a near-infrared tracer was infused into the inguinal lymph node. Collecting lymphatic vessel contractility and valve function could be easily visualized after the infusion. A diameter tracking method was established and the diameter of the vessel was found to closely correlate to near-infrared fluorescence signal. Phasic contractility measures of frequency and amplitude were established using an automated algorithm. The methods were validated by tracking the vessel response to topical application of a contractile agonist, prostaglandin F2α, and by demonstrating the potential of the technique for non-invasive evaluation of modifiers of lymphatic function. These new methods will enable high-resolution imaging and quantification of collecting lymphatic vessel function in animal models and may have future clinical applications. PMID:26960708

  7. Calcitriol attenuates cardiac remodeling and dysfunction in a murine model of polycystic ovary syndrome.

    Science.gov (United States)

    Gao, Ling; Cao, Jia-Tian; Liang, Yan; Zhao, Yi-Chao; Lin, Xian-Hua; Li, Xiao-Cui; Tan, Ya-Jing; Li, Jing-Yi; Zhou, Cheng-Liang; Xu, Hai-Yan; Sheng, Jian-Zhong; Huang, He-Feng

    2016-05-01

    Polycystic ovary syndrome (PCOS) is a complex reproductive and metabolic disorder affecting 10 % of reproductive-aged women, and is well associated with an increased prevalence of cardiovascular risk factors. However, there are few data concerning the direct association of PCOS with cardiac pathologies. The present study aims to investigate the changes in cardiac structure, function, and cardiomyocyte survival in a PCOS model, and explore the possible effect of calcitriol administration on these changes. PCOS was induced in C57BL/6J female mice by chronic dihydrotestosterone administration, as evidenced by irregular estrous cycles, obesity and dyslipidemia. PCOS mice progressively developed cardiac abnormalities including cardiac hypertrophy, interstitial fibrosis, myocardial apoptosis, and cardiac dysfunction. Conversely, concomitant administration of calcitriol significantly attenuated cardiac remodeling and cardiomyocyte apoptosis, and improved cardiac function. Molecular analysis revealed that the beneficial effect of calcitriol was associated with normalized autophagy function by increasing phosphorylation levels of AMP-activated protein kinase and inhibiting phosphorylation levels of mammalian target of rapamycin complex. Our findings provide the first evidence for the presence of cardiac remodeling in a PCOS model, and vitamin D supplementation may be a potential therapeutic strategy for the prevention and treatment of PCOS-related cardiac remodeling.

  8. Non-cell autonomous cues for enhanced functionality of human embryonic stem cell-derived cardiomyocytes via maturation of sarcolemmal and mitochondrial KATP channels

    Science.gov (United States)

    Keung, Wendy; Ren, Lihuan; Sen Li; Wong, Andy On-Tik; Chopra, Anant; Kong, Chi-Wing; Tomaselli, Gordon F.; Chen, Christopher S.; Li, Ronald A.

    2016-01-01

    Human embryonic stem cells (hESCs) is a potential unlimited ex vivo source of ventricular (V) cardiomyocytes (CMs), but hESC-VCMs and their engineered tissues display immature traits. In adult VCMs, sarcolemmal (sarc) and mitochondrial (mito) ATP-sensitive potassium (KATP) channels play crucial roles in excitability and cardioprotection. In this study, we aim to investigate the biological roles and use of sarcKATP and mitoKATP in hESC-VCM. We showed that SarcIK, ATP in single hESC-VCMs was dormant under baseline conditions, but became markedly activated by cyanide (CN) or the known opener P1075 with a current density that was ~8-fold smaller than adult; These effects were reversible upon washout or the addition of GLI or HMR1098. Interestingly, sarcIK, ATP displayed a ~3-fold increase after treatment with hypoxia (5% O2). MitoIK, ATP was absent in hESC-VCMs. However, the thyroid hormone T3 up-regulated mitoIK, ATP, conferring diazoxide protective effect on T3-treated hESC-VCMs. When assessed using a multi-cellular engineered 3D ventricular cardiac micro-tissue (hvCMT) system, T3 substantially enhanced the developed tension by 3-folds. Diazoxide also attenuated the decrease in contractility induced by simulated ischemia (1% O2). We conclude that hypoxia and T3 enhance the functionality of hESC-VCMs and their engineered tissues by selectively acting on sarc and mitoIK, ATP. PMID:27677332

  9. Dietary exposure to ergot alkaloids decreases contractility of bovine mesenteric vasculature.

    Science.gov (United States)

    Egert, A M; Kim, D H; Schrick, F N; Harmon, D L; Klotz, J L

    2014-04-01

    Ergot alkaloids are hypothesized to cause vasoconstriction in the midgut, and prior exposure may affect the vasoactivity of these compounds. The objectives of this study were to profile vasoactivity of ergot alkaloids in bovine mesenteric artery (MA) and vein (MV) and determine if previous exposure to endophyte-infected tall fescue seed affected vasoactivity of ergocryptine (ERP), ergotamine (ERT), ergocristine (ERS), ergocornine (ERO), ergonovine (ERN), lysergic acid (LSA), ergovaline-containing tall fescue seed extract (EXT), and 5-hydroxytryptamine (5HT; serotonin). Ruminally cannulated Angus steers (n = 12; BW = 547 ± 31 kg) were paired by weight and randomly assigned to 6 blocks. Steers were ruminally dosed daily with 1 kg of either endophyte-infected (E+; 4.45 mg ergovaline/kg DM) or endophyte-free (E-; 0 mg ergovaline/kg DM) tall fescue seed for 21 d before slaughter. Branches of MA and MV supporting the cranial portion of the ileum were collected after slaughter on d 22, placed in a modified Krebs-Henseleit buffer on ice, cleaned, sectioned, and mounted in a multimyograph chamber. Contractile response was normalized to a maximum KCl response. Inner diameter (P = 0.04) and outer diameter (P = 0.02) of MA were smaller for E+ steers than E- steers. Maximum contractile responses to 120 mM KCl were not different between seed treatments in MA (P = 0.33; E-: 2.67 ± 0.43 g; E+: 3.33 ± 0.43 g) or MV (P = 0.26; E-: 2.01 ± 0.18 g; E+: 1.81 ± 0.18 g). Steers receiving E+ had a smaller (P < 0.01) MA contractile response than E- steers to ERP, ERT, ERS, ERO, ERN, EXT, and 5HT. Steers receiving E+ had a smaller (P < 0.05) MV contractile response than E- steers to ERP, ERT, ERS, ERN, EXT, and 5HT. Lysergic acid failed to induce a contractile response in MA and MV. The contractile response in MA and MV of E- steers produced by 5HT was very large. The EXT was the most potent (P < 0.05) agonist in MV and MA of E+ steers. These data showed that ergot alkaloids were

  10. Psychoanalysis: a dysfunctional family?

    Science.gov (United States)

    Grosskurth, P

    1998-01-01

    The discussion opens with an account of the author's mother's bizarre family in which a strong, charismatic grandmother maintained absolute control over her large family by encouraging a neurotic dependence in them through daily reports of their complaints. Getting interested in psychoanalysis in an effort to understand the dynamics of this dysfunctional family, the author, a biographer, turned to the study of Melanie Klein, becoming entranced by her ideas. Her research also revealed how Klein had discouraged her followers from developing ideas that diverged in any way from her own. Her portrait of the pioneer analyst provoked intense indignation. A similar pattern of absolute loyalty to his person and theories was to be found in Freud's Secret Committee, formed primarily as a means of getting rid of Jung who had been showing disturbing signs of independence. When Ferenczi and Rank began to pursue independent lines of enquiry in their work, they too were though to be undermining the foundations of classical psychoanalysis. Finally, the author concludes that though there have been sorry incidents in psychoanalysis, we should be mature enough to accept both the contributions of the early pioneers and the realizations that new ideas must be permitted to evolve.

  11. Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

    Energy Technology Data Exchange (ETDEWEB)

    Morton, M.J., E-mail: michael.morton@astrazeneca.com [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Armstrong, D.; Abi Gerges, N. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Bridgland-Taylor, M. [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Pollard, C.E.; Bowes, J.; Valentin, J.-P. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom)

    2014-09-01

    Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility.

  12. Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

    International Nuclear Information System (INIS)

    Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility

  13. Cardiomyocyte proliferation and progenitor cell recruitment underlie therapeutic regeneration after myocardial infarction in the adult mouse heart.

    Science.gov (United States)

    Malliaras, Konstantinos; Zhang, Yiqiang; Seinfeld, Jeffrey; Galang, Giselle; Tseliou, Eleni; Cheng, Ke; Sun, Baiming; Aminzadeh, Mohammad; Marbán, Eduardo

    2013-02-01

    Cardiosphere-derived cells (CDCs) have been shown to regenerate infarcted myocardium in patients after myocardial infarction (MI). However, whether the cells of the newly formed myocardium originate from the proliferation of adult cardiomyocytes or from the differentiation of endogenous stem cells remains unknown. Using genetic fate mapping to mark resident myocytes in combination with long-term BrdU pulsing, we investigated the origins of postnatal cardiomyogenesis in the normal, infarcted and cell-treated adult mammalian heart. In the normal mouse heart, cardiomyocyte turnover occurs predominantly through proliferation of resident cardiomyocytes at a rate of ∼1.3-4%/year. After MI, new cardiomyocytes arise from both progenitors as well as pre-existing cardiomyocytes. Transplantation of CDCs upregulates host cardiomyocyte cycling and recruitment of endogenous progenitors, while boosting heart function and increasing viable myocardium. The observed phenomena cannot be explained by cardiomyocyte polyploidization, bi/multinucleation, cell fusion or DNA repair. Thus, CDCs induce myocardial regeneration by differentially upregulating two mechanisms of endogenous cell proliferation.

  14. Antifungal miconazole induces cardiotoxicity via inhibition of APE/Ref-1-related pathway in rat neonatal cardiomyocytes.

    Science.gov (United States)

    Won, Kyung-Jong; Lin, Hai Yue; Jung, Soohyun; Cho, Soo Min; Shin, Ho-Chul; Bae, Young Min; Lee, Seung Hyun; Kim, Hyun-Jung; Jeon, Byeong Hwa; Kim, Bokyung

    2012-04-01

    Effects of miconazole, an azole antifungal, have not been fully determined in cardiomyocytes. We therefore identified the transcriptome in neonatal rat cardiomyocytes responding to miconazole using DNA microarray analysis and selected a gene and investigated its role in cardiomyocytes. Miconazole dose-dependently increased the levels of superoxide (O(2)(-)) and apoptosis in cardiomyocytes; these increases were inhibited by treatment with antioxidants. The DNA microarray revealed that 4163 genes were upregulated and 4829 genes downregulated by more than threefold in miconazole-treated cardiomyocytes compared with the vehicle-treated control. Moreover, redox homeostasis-, oxidative stress-, and reactive oxygen species (ROS)-related categories of genes were strongly affected by miconazole treatment. Among genes overlapped in all these categories, apurinic/apyrimidinic endonuclease-1/redox factor-1 (APE/Ref-1), a redox-related gene, was prominent and was diminished in the miconazole-treated group. Changes in the O(2)(-) production and apoptosis induction in response to miconazole were inhibited in cardiomyocytes transfected with adenoviral APE/Ref-1. Overexpression of APE/Ref-1 reversed the reduction in beating frequency induced by miconazole. Our results demonstrate that miconazole may induce rat cardiotoxicity via a ROS-mediated pathway, which is initiated by the inhibition of APE/Ref-1 expression. This possible new adverse event in cardiomyocyte function caused by miconazole may provide a basis for the development of novel antifungal agents.

  15. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS mediated cardiomyocyte hypertrophy

    NARCIS (Netherlands)

    Tigchelaar, Wardit; Yu, Hongjuan; De Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Sillje, Herman H W

    2015-01-01

    Recently, a genetic variant in the mitochondrial exo/endo nuclease EXOG, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and hypertrop

  16. Highly efficient derivation of ventricular cardiomyocytes from induced pluripotent stem cells with a distinct epigenetic signature

    Institute of Scientific and Technical Information of China (English)

    Huansheng Xu; Ibrahim J Domian; Erding Hu; Robert Willette; John Lepore; Alexander Meissner; Zhong Wang; Kenneth R Chien; B Alexander Yi; Hao Wu; Christoph Bock; Hongcang Gu; Kathy O Lui; Joo-Hye C Park; Ying Shao; Alyssa K Riley

    2012-01-01

    Cardiomyocytes derived from pluripotent stem cells can be applied in drug testing,disease modeling and cellbased therapy.However,without procardiogenic growth factors,the efficiency of cardiomyogenesis from pluripotent stem cells is usually low and the resulting cardiomyocyte population is heterogeneous.Here,we demonstrate that induced pluripotent stem cells (iPSCs) can be derived from murine ventricular myocytes (VMs),and consistent with other reports of iPSCs derived from various somatic cell types,VM-derived iPSCs (ViPSCs) exhibit a markedly higher propensity to spontaneously differentiate into beating cardiomyocytes as compared to genetically matched embryonic stem cells (ESCs) or iPSCs derived from tail-tip fibroblasts.Strikingly,the majority of ViPSC-derived cardiomyocytes display a ventricular phenotype.The enhanced ventricular myogenesis in ViPSCs is mediated via increased numbers of cardiovascular progenitors at early stages of differentiation.In order to investigate the mechanism of enhanced ventricular myogenesis from ViPSCs,we performed global gene expression and DNA methylation analysis,which revealed a distinct epigenetic signature that may be involved in specifying the VM fate in pluripotent stem cells.

  17. Spermine ameliorates ischemia/reperfusion injury in cardiomyocytes via regulation of autophagy

    Science.gov (United States)

    Duan, Qunjun; Yang, Weijun; Jiang, Daming; Tao, Kaiyu; Dong, Aiqiang; Cheng, Haifeng

    2016-01-01

    Myocardial infarction could result in high morbidity and mortality and heart diseases of children have becoming prevalent. Functions of spermine administration on cardiomyocytes remain unknown. The present study was designed to investigate the role of spermine pretreatment on myocardial ischemia/reperfusion injury (IRI). A cell model of simulated ischemia/reperfusion injury was established by incubating neonatal Sprague-Dawley rat cardiomyocytes in ischemia medium and re-cultured in normal medium. Of note, spermine pretreatment significantly reduced apoptosis and increased viability of immature cardiomyocytes. Spermine pretreatment enhanced autophagic flux as determined by confocal microscopy and transmission electron microscopy. Furthermore, proteins of mammalian target of rapamycin (mTOR) pathway were significantly reduced in response to spermine pretreatment during IRI, while proteins related to autophagy were up-regulated. The cell viability was enhanced and apoptosis decreased by rapamycin after spermine pretreatment, while these were reversed by 3-methyladenine. However, when immature cardiomyocytes were pretreated with rapamycin or 3-methyladenine, followed by IRI and spermine administration, no significant changes of viability and apoptosis were observed. In conclusion, this study suggests that spermine is a potential novel approach for preventing IRI, especially in children. PMID:27725878

  18. Engineered Microenvironments for the Maturation and Observation of Human Embryonic Stem Cell Derived Cardiomyocytes

    Science.gov (United States)

    Salick, Max R.

    The human heart is a dynamic system that undergoes substantial changes as it develops and adapts to the body's growing needs. To better understand the physiology of the heart, researchers have begun to produce immature heart muscle cells, or cardiomyocytes, from pluripotent stem cell sources with remarkable efficiency. These stem cell-derived cardiomyocytes hold great potential in the understanding and treatment of heart disease; however, even after prolonged culture, these cells continue to exhibit an immature phenotype, as indicated by poor sarcomere organization and calcium handling, among other features. The lack of maturation that is observed in these cardiomyocytes greatly limits their applicability towards drug screening, disease modeling, and cell therapy applications. The mechanical environment surrounding a cell has been repeatedly shown to have a large impact on that cell's behavior. For this reason, we have implemented micropatterning methods to mimic the level of alignment that occurs in the heart in vivo in order to study how this alignment may help the cells to produce a more mature sarcomere phenotype. It was discovered that the level of sarcomere organization of a cardiomyocyte can be strongly influenced by the micropattern lane geometry on which it adheres. Steps were taken to optimize this micropattern platform, and studies of protein organization, gene expression, and myofibrillogenesis were conducted. Additionally, a set of programs was developed to provide quantitative analysis of the level of sarcomere organization, as well as to assist with several other tissue engineering applications.

  19. PGC-1α and reactive oxygen species regulate human embryonic stem cell-derived cardiomyocyte function

    NARCIS (Netherlands)

    M.J. Birket (Matthew); S. Casini (Simona); G. Kosmidis (Georgios); D.J. Elliott (David); A.A. Gerencser (Akos); A. Baartscheer (Antonius); C. Schumacher (Cees); P.G. Mastroberardino (Pier); A.G. Elefanty (Andrew); E.G. Stanley