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Sample records for angiotensin receptor type

  1. Angiotensin type 2 receptor (AT2R) and receptor Mas

    DEFF Research Database (Denmark)

    Villela, Daniel; Leonhardt, Julia; Patel, Neal

    2015-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striking...

  2. Cardiovascular effects of the angiotensin type 2 receptor.

    Science.gov (United States)

    Faria-Costa, Gabriel; Leite-Moreira, Adelino; Henriques-Coelho, Tiago

    2014-01-01

    The angiotensin type 2 receptor, AT2R, has been described as having opposite effects to the angiotensin type 1 receptor, AT1R. Although the quantities of the AT2R found in the adult are low, its expression rises in pathological situations. The AT2R has three major signaling pathways: activation of serine/threonine phosphatases (promoting apoptosis and antioxidant effects), activation of the bradykinin/NO/cGMP pathway (promoting vasodilation), and activation of phospholipase A2 (associated with regulation of potassium currents). The AT2R appears to have effects in vascular remodeling, atherosclerosis prevention and blood pressure lowering (when associated with an AT1R inhibitor). After myocardial infarction, the AT2R appears to decrease infarct size, cardiac hypertrophy and fibrosis, and to improve cardiac function. However, its role in the heart is controversial. In the kidney, the AT2R promotes natriuresis. Until now, treatment directed at the renin-angiotensin-aldosterone system has been based on angiotensin-converting enzyme inhibitors or angiotensin type 1 receptor blockers. The study of the AT2R has been revolutionized by the discovery of a direct agonist, C21, which promises to become part of the treatment of cardiovascular disease. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  3. The angiotensin type 2 receptor and the kidney

    DEFF Research Database (Denmark)

    Peluso, Antonio A B; Santos, Robson A S; Unger, Thomas

    2017-01-01

    PURPOSE OF REVIEW: Angiotensin II is a main regulator of kidney function. Renal actions mediated by the angiotensin AT1 receptor have been well known for many years. In contrast, several details of angiotensin AT2 receptor actions in kidney physiology and pathophysiology were only described very...

  4. The angiotensin II type 1 receptor antagonist Losartan binds and activates bradykinin B2 receptor signaling

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Olsen, Kristine Boisen; Erikstrup, Niels;

    2011-01-01

    The angiotensin II type 1 receptor (AT1R) blocker (ARB) Losartan has cardioprotective effects during ischemia-reperfusion injury and inhibits reperfusion arrhythmias -effects that go beyond the benefits of lowering blood pressure. The renin-angiotensin and kallikrein-kinin systems are intricately...

  5. Angiotensin-II type 1 receptor gene polymorphism and diabetic microangiopathy

    DEFF Research Database (Denmark)

    Tarnow, L; Cambien, Francois; Rossing, P

    1996-01-01

    BACKGROUND: Genotypic abnormalities of the renin-angiotensin system have been suggested as risk factors for the development of hypertension, diabetic nephropathy and proliferative retinopathy. Most of the known actions of angiotensin-II are exerted through the angiotensin-II type 1 receptor, whic...

  6. The angiotensintype 1 receptor and receptor-associated proteins

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The mechanisms of regulation, activation and signal transduction of the angiotensin Ⅱ(Ang Ⅱ) type 1 (AT1) receptor have been studied extensively in the decade after its cloning. The AT1receptor is a major component of the renin-angiotensin system (RAS). It mediates the classical biological actions of Ang Ⅱ. Among the structures required for regulation and activation of the receptor, its carboxylterminal region plays crucial roles in receptor internalization, desensitization and phosphorylation. The mechanisms involved in heterotrimeric G-protein coupling to the receptor, activation of the downstreamsignaling pathway by G proteins and the Ang Ⅱ signal transduction pathways leading to specific cellularresponses are discussed. In addition, recent work on the identification and characterization of novel proteinsassociated with carboxyl-terminus of the AT1 receptor is presented. These novel proteins will advance ourunderstanding of how the receptor is internalized and recycled as they provide molecular mechanisms for the activation and regulation of G-protein-coupled receptors.

  7. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS

    DEFF Research Database (Denmark)

    Leonhardt, Julia; Steckelings, Ulrike Muscha

    2017-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may...... indicate heterodimerization of these receptors. Therefore, this study investigated the molecular and functional interplay between MAS and the AT2R. Molecular interactions were assessed by fluorescence resonance energy transfer and by cross correlation spectroscopy in human embryonic kidney-293 cells...... transfected with vectors encoding fluorophore-tagged MAS or AT2R. Functional interaction of AT2R and MAS was studied in astrocytes with CX3C chemokine receptor-1 messenger RNA expression as readout. Coexpression of fluorophore-tagged AT2R and MAS resulted in a fluorescence resonance energy transfer efficiency...

  8. Differential roles of Angiotensinogen and Angiotensin Receptor type 1 polymorphisms in breast cancer risk.

    NARCIS (Netherlands)

    Gonzalez-Zuloet Ladd, A.M.; Arias Vasquez, A.; Siemes, C.; Yazdanpanah, M.; Coebergh, J.W.W.; Hofman, A.; Stricker, B.H.C.; Duijn, C.M. van

    2007-01-01

    While angiotensinogen (AGT) seems to have anti proliferative properties, angiotensin II (ATII) is a potent growth factor and it mediates its actions through the angiotensin type 1 receptor (AGTR1). In the AGT gene, the M235T polymorphism has been associated with the variation in angiotensinogen leve

  9. Differential roles of Angiotensinogen and Angiotensin Receptor type 1 polymorphisms in breast cancer risk.

    NARCIS (Netherlands)

    Gonzalez-Zuloet Ladd, A.M.; Arias Vasquez, A.; Siemes, C.; Yazdanpanah, M.; Coebergh, J.W.W.; Hofman, A.; Stricker, B.H.C.; Duijn, C.M. van

    2007-01-01

    While angiotensinogen (AGT) seems to have anti proliferative properties, angiotensin II (ATII) is a potent growth factor and it mediates its actions through the angiotensin type 1 receptor (AGTR1). In the AGT gene, the M235T polymorphism has been associated with the variation in angiotensinogen leve

  10. Differential roles of Angiotensinogen and Angiotensin Receptor type 1 polymorphisms in breast cancer risk.

    NARCIS (Netherlands)

    Gonzalez-Zuloet Ladd, A.M.; Arias Vasquez, A.; Siemes, C.; Yazdanpanah, M.; Coebergh, J.W.W.; Hofman, A.; Stricker, B.H.C.; Duijn, C.M. van

    2007-01-01

    While angiotensinogen (AGT) seems to have anti proliferative properties, angiotensin II (ATII) is a potent growth factor and it mediates its actions through the angiotensin type 1 receptor (AGTR1). In the AGT gene, the M235T polymorphism has been associated with the variation in angiotensinogen

  11. Regulation of blood pressure by the type 1A angiotensin II receptor gene.

    OpenAIRE

    Ito, M.; Oliverio, M I; Mannon, P J; Best, C F; Maeda, N.; Smithies, O.; Coffman, T M

    1995-01-01

    The renin-angiotensin system plays a critical role in sodium and fluid homeostasis. Genetic or acquired alterations in the expression of components of this system are strongly implicated in the pathogenesis of hypertension. To specifically examine the physiological and genetic functions of the type 1A receptor for angiotensin II, we have disrupted the mouse gene encoding this receptor in embryonic stem cells by gene targeting. Agtr1A(-/-) mice were born in expected numbers, and the histomorph...

  12. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS.

    Science.gov (United States)

    Leonhardt, Julia; Villela, Daniel C; Teichmann, Anke; Münter, Lisa-Marie; Mayer, Magnus C; Mardahl, Maibritt; Kirsch, Sebastian; Namsolleck, Pawel; Lucht, Kristin; Benz, Verena; Alenina, Natalia; Daniell, Nicholas; Horiuchi, Masatsugu; Iwai, Masaru; Multhaup, Gerhard; Schülein, Ralf; Bader, Michael; Santos, Robson A; Unger, Thomas; Steckelings, Ulrike Muscha

    2017-06-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may indicate heterodimerization of these receptors. Therefore, this study investigated the molecular and functional interplay between MAS and the AT2R. Molecular interactions were assessed by fluorescence resonance energy transfer and by cross correlation spectroscopy in human embryonic kidney-293 cells transfected with vectors encoding fluorophore-tagged MAS or AT2R. Functional interaction of AT2R and MAS was studied in astrocytes with CX3C chemokine receptor-1 messenger RNA expression as readout. Coexpression of fluorophore-tagged AT2R and MAS resulted in a fluorescence resonance energy transfer efficiency of 10.8 ± 0.8%, indicating that AT2R and MAS are capable to form heterodimers. Heterodimerization was verified by competition experiments using untagged AT2R and MAS. Specificity of dimerization of AT2R and MAS was supported by lack of dimerization with the transient receptor potential cation channel, subfamily C-member 6. Dimerization of the AT2R was abolished when it was mutated at cysteine residue 35. AT2R and MAS stimulation with the respective agonists, Compound 21 or angiotensin-(1-7), significantly induced CX3C chemokine receptor-1 messenger RNA expression. Effects of each agonist were blocked by an AT2R antagonist (PD123319) and also by a MAS antagonist (A-779). Knockout of a single of these receptors made astrocytes unresponsive for both agonists. Our results suggest that MAS and the AT2R form heterodimers and that-at least in astrocytes-both receptors functionally depend on each other. © 2017 American Heart Association, Inc.

  13. Angiotensin II type 2 receptor expression after vascular injury: differing effects of angiotensin-converting enzyme inhibition and angiotensin receptor blockade.

    Science.gov (United States)

    Barker, Thomas A; Massett, Michael P; Korshunov, Vyacheslav A; Mohan, Amy M; Kennedy, Amy J; Berk, Bradford C

    2006-11-01

    It has been suggested that the effects of angiotensin II type 1 receptor (AT1R) blockers are in part because of angiotensin II type 2 receptor (AT2R) signaling. Interactions between the AT2R and kinins modulate cardiovascular function. Because AT2R expression increases after vascular injury, we hypothesized that the effects on vascular remodeling of the AT1R blocker valsartan and the ACE inhibitor benazepril require AT2R signaling through the bradykinin 1 and 2 receptors (B1R and B2R). To test this hypothesis, Brown Norway rats were assigned to 8 treatments (n=16): valsartan, valsartan+PD123319 (AT2R inhibitor), valsartan+des-arg9-[Leu8]-bradykinin (B1R inhibitor), valsartan+HOE140 (B2R inhibitor), benazepril, benazepril+HOE140, amlodipine, and vehicle. After 1 week of treatment, carotid balloon injury was performed. Two weeks later, carotids were harvested for morphometry and analysis of receptor expression by immunohistochemistry and Western blotting. Valsartan and benazepril significantly reduced the intima:media ratio compared with vehicle. Blockade of AT2R, B1R, or B2R in the presence of valsartan prevented the reduction seen with valsartan alone. B2R blockade inhibited the effect of benazepril. Injury increased AT1R, AT2R, B1R, and B2R expression. Treatment with valsartan but not benazepril significantly increased intima AT2R expression 2-fold compared with vehicle, which was not reversed by inhibition of AT2R, B1R, and B2R. Functionally, valsartan increased intimal cGMP levels compared with vehicle, and this increase was inhibited by blocking the AT2R, B1R, and B2R. Results suggest that AT2R expression and increased cGMP represent a molecular mechanism that differentiates AT1R blockers, such as valsartan, from angiotensin-converting enzyme inhibitors like benazepril.

  14. Angiotensin-II type 1 receptor gene polymorphism and diabetic microangiopathy

    DEFF Research Database (Denmark)

    Tarnow, L; Cambien, Francois; Rossing, P

    1996-01-01

    (41%) / 14 (7%) vs. 97 (51%) / 80 (42%) / 13 (7%) had AA/AC/CC genotypes, respectively. The allele frequencies (A/C) in patients with nephropathy (0.73/0.27) and patients with normoalbuminuria (0.72/0.28) were also similar. No difference in genotype distribution between IDDM patients...... with proliferative retinopathy and without diabetic retinopathy was found either: 77 (50%) / 66 (42%) / 13 (8%) vs. 42 (63%) / 22 (33%) / 3 (4%) had AA/AC/CC genotypes, respectively. CONCLUSIONS: The A1166-->C polymorphism in the angiotensin-II type 1 receptor gene does not contribute to the genetic susceptibility......BACKGROUND: Genotypic abnormalities of the renin-angiotensin system have been suggested as risk factors for the development of hypertension, diabetic nephropathy and proliferative retinopathy. Most of the known actions of angiotensin-II are exerted through the angiotensin-II type 1 receptor, which...

  15. Recent advances and findings of angiotensin type 2 receptor:a review

    Institute of Scientific and Technical Information of China (English)

    ZUO Yu-mei; WANG Yuan; LIU Jian-ping

    2010-01-01

    @@ Angiotensinogen is a member of the serpin family. It is produced constitutively and released into the circulation mainly by the liver. Angiotensinogen forms angiotensin Ⅰ by action of the circulated renin released from the kidney. Angiotensin Ⅱ (Ang Ⅱ), an octapeptide hormone with sequence Asp-Arg-Val-Tyr-Ile-His-Pro-Phe,is converted from angiotensin Ⅰ through removal of two terminal residues by the angiotensin-converting enzyme (ACE) mostly catalyzed in the lung.1 This peptide binds to two subtype receptors, angiotensin type 1 receptor (AT1R) and angiotensin type 2 receptor (AT2R),members of the superfamily of heptahelical G protein coupled receptors, with different affinities.2 It is well known that AT1R and AT2R crosstalk and lead to counterregulatory functions in many systems, especially the cardiovascular system.3 Accumulating data established the roles of AT1R in the classic actions of Ang Ⅱ including vasoconstriction and cardiovascular hypertrophy, whereas AT2R is suggested to exert direct functions in vasodilation and antigrowth effects.4 Recent publications provide new insights into the roles of AT2R with increasing responsibilities. Recent progresses in AT2R research are reviewed in this article.

  16. Urinary angiotensin-converting enzyme 2 increases in diabetic nephropathy by angiotensin II type 1 receptor blocker olmesartan.

    Science.gov (United States)

    Abe, Masanori; Oikawa, Osamu; Okada, Kazuyoshi; Soma, Masayoshi

    2015-03-01

    Angiotensin-converting enzyme 2 (ACE2) is a member of the renin-angiotensin system that degrades angiotensin (Ang) II to the seven-amino acid peptide fragment Ang-(1-7). We evaluated the changes in urinary ACE2 levels in response to treatment with the angiotensin II type 1 receptor blocker olmesartan in diabetes patients with nephropathy. This prospective, open-label, interventional study was conducted with 31 type 2 diabetes patients with nephropathy. After initial evaluation, patients received 20 mg/day olmesartan, which was increased to 40 mg/day over a 24-week period. In diabetes patients with chronic kidney disease, olmesartan significantly increased urinary ACE2 levels independently of blood pressure and plasma aldosterone levels and reduced albuminuria, urinary liver-type fatty acid binding protein (L-FABP), and plasma aldosterone levels. Multivariable regression analysis revealed that the change in urinary L-FABP levels was an independent predictor of increased urinary ACE2 levels. Olmesartan may have the unique effect of increasing urinary ACE2 levels. However, whether this contributes to olmesartan's renoprotective effect must be examined further. © The Author(s) 2014.

  17. Enhancement of Adipocyte Browning by Angiotensin II Type 1 Receptor Blockade

    Science.gov (United States)

    Tsukuda, Kana; Mogi, Masaki; Iwanami, Jun; Kanno, Harumi; Nakaoka, Hirotomo; Wang, Xiao-Li; Bai, Hui-Yu; Shan, Bao-Shuai; Kukida, Masayoshi; Higaki, Akinori; Yamauchi, Toshifumi; Min, Li-Juan; Horiuchi, Masatsugu

    2016-01-01

    Browning of white adipose tissue (WAT) has been highlighted as a new possible therapeutic target for obesity, diabetes and lipid metabolic disorders, because WAT browning could increase energy expenditure and reduce adiposity. The new clusters of adipocytes that emerge with WAT browning have been named ‘beige’ or ‘brite’ adipocytes. Recent reports have indicated that the renin-angiotensin system (RAS) plays a role in various aspects of adipose tissue physiology and dysfunction. The biological effects of angiotensin II, a major component of RAS, are mediated by two receptor subtypes, angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R). However, the functional roles of angiotensin II receptor subtypes in WAT browning have not been defined. Therefore, we examined whether deletion of angiotensin II receptor subtypes (AT1aR and AT2R) may affect white-to-beige fat conversion in vivo. AT1a receptor knockout (AT1aKO) mice exhibited increased appearance of multilocular lipid droplets and upregulation of thermogenic gene expression in inguinal white adipose tissue (iWAT) compared to wild-type (WT) mice. AT2 receptor-deleted mice did not show miniaturization of lipid droplets or alteration of thermogenic gene expression levels in iWAT. An in vitro experiment using adipose tissue-derived stem cells showed that deletion of the AT1a receptor resulted in suppression of adipocyte differentiation, with reduction in expression of thermogenic genes. These results indicate that deletion of the AT1a receptor might have some effects on the process of browning of WAT and that blockade of the AT1 receptor could be a therapeutic target for the treatment of metabolic disorders. PMID:27992452

  18. Angiotensin II type 1 receptor blockade restores angiotensin-(1-7)-induced coronary vasodilation in hypertrophic rat hearts.

    Science.gov (United States)

    Souza, Álvaro P S; Sobrinho, Deny B S; Almeida, Jônathas F Q; Alves, Gisele M M; Macedo, Larissa M; Porto, Juliana E; Vêncio, Eneida F; Colugnati, Diego B; Santos, Robson A S; Ferreira, Anderson J; Mendes, Elizabeth P; Castro, Carlos H

    2013-11-01

    The aim of the present study was to investigate the coronary effects of Ang-(1-7) [angiotensin-(1-7)] in hypertrophic rat hearts. Heart hypertrophy was induced by abdominal aorta CoA (coarctation). Ang-(1-7) and AVE 0991, a non-peptide Mas-receptor agonist, at picomolar concentration, induced a significant vasodilation in hearts from sham-operated rats. These effects were blocked by the Mas receptor antagonist A-779. Pre-treatment with L-NAME (N(G)-nitro-L-arginine methyl ester) or ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinozalin-1-one) [NOS (NO synthase) and soluble guanylate cyclase inhibitors respectively] also abolished the effect of Ang-(1-7) in control hearts. The coronary vasodilation produced by Ang-(1-7) and AVE 0991 was completely blunted in hypertrophic hearts. Chronic oral administration of losartan in CoA rats restored the coronary vasodilation effect of Ang-(1-7). This effect was blocked by A-779 and AT2 receptor (angiotensin II type 2 receptor) antagonist PD123319. Acute pre-incubation with losartan also restored the Ang-(1-7)-induced, but not BK (bradykinin)-induced, coronary vasodilation in hypertrophic hearts. This effect was inhibited by A-779, PD123319 and L-NAME. Chronic treatment with losartan did not change the protein expression of Mas and AT2 receptor and ACE (angiotensin-converting enzyme) and ACE2 in coronary arteries from CoA rats, but induced a slight increase in AT2 receptor in aorta of these animals. Ang-(1-7)-induced relaxation in aortas from sham-operated rats was absent in aortas from CoA rats. In vitro pre-treatment with losartan restored the Ang-(1-7)-induced relaxation in aortic rings of CoA rats, which was blocked by the Mas antagonist A-779 and L-NAME. These data demonstrate that Mas is strongly involved in coronary vasodilation and that AT1 receptor (angiotensin II type 1 receptor) blockade potentiates the vasodilatory effects of Ang-(1-7) in the coronary beds of pressure-overloaded rat hearts through NO-related AT2- and Mas-receptor

  19. Angiotensin II type 1 receptor signalling regulates microRNA differentially in cardiac fibroblasts and myocytes

    DEFF Research Database (Denmark)

    Jeppesen, Pia Lindgren; Christensen, Gitte Lund; Schneider, Mikael

    2011-01-01

    Background and purpose: The Angiotensin II type 1 receptor (AT(1) R) is a key regulator of blood pressure and cardiac contractility and is profoundly involved in development of cardiac disease. Since several microRNAs (miRNAs) have been implicated in cardiac disease, we asked whether miRNAs might...

  20. Activation of D4 dopamine receptor decreases angiotensin II type 1 receptor expression in rat renal proximal tubule cells.

    Science.gov (United States)

    Chen, Ken; Deng, Kun; Wang, Xiaoyan; Wang, Zhen; Zheng, Shuo; Ren, Hongmei; He, Duofen; Han, Yu; Asico, Laureano D; Jose, Pedro A; Zeng, Chunyu

    2015-01-01

    The dopaminergic and renin-angiotensin systems interact to regulate blood pressure. Disruption of the D4 dopamine receptor gene in mice produces hypertension that is associated with increased renal angiotensin type 1 (AT1) receptor expression. We hypothesize that the D4 receptor can inhibit AT1 receptor expression and function in renal proximal tubule cells from Wistar-Kyoto (WKY) rats, but the D4 receptor regulation of AT1 receptor is aberrant in renal proximal tubule cells from spontaneously hypertensive rats (SHRs). The D4 receptor agonist, PD168077, decreased AT1 receptor protein expression in a time- and concentration-dependent manner in WKY cells. By contrast, in SHR cells, PD168077 increased AT1 receptor protein expression. The inhibitory effect of D4 receptor on AT1 receptor expression in WKY cells was blocked by a calcium channel blocker, nicardipine, or calcium-free medium, indicating that calcium is involved in the D4 receptor-mediated signaling pathway. Angiotensin II increased Na(+)-K(+) ATPase activity in WKY cells. Pretreatment with PD168077 decreased the stimulatory effect of angiotensin II on Na(+)-K(+) ATPase activity in WKY cells. In SHR cells, the inhibitory effect of D4 receptor on angiotensin II-mediated stimulation of Na(+)-K(+) ATPase activity was aberrant; pretreatment with PD168077 augmented the stimulatory effect of AT1 receptor on Na(+)-K(+) ATPase activity in SHR cells. This was confirmed in vivo; pretreatment with PD128077 for 1 week augmented the antihypertensive and natriuretic effect of losartan in SHRs but not in WKY rats. We suggest that an aberrant interaction between D4 and AT1 receptors may play a role in the abnormal regulation of sodium excretion in hypertension.

  1. Ischemic heart disease down-regulates angiotensin type 1 receptor mRNA in human coronary arteries

    DEFF Research Database (Denmark)

    Wackenfors, Angelica; Emilson, Malin; Ingemansson, Richard;

    2004-01-01

    Angiotensin II is important in the development of cardiovascular disease. In the present study, angiotensin II receptor mRNA levels were quantified by real-time polymerase chain reaction (real-time PCR) in human coronary arteries from patients with ischemic heart disease and controls. Furthermore......, the suitability of artery culture for studying angiotensin receptor changes was evaluated by in vitro pharmacology and real-time PCR. The angiotensin type 1 (AT1) receptor mRNA levels were down-regulated in human coronary arteries from patients with ischemic heart disease as compared to controls (P

  2. Association of angiotensin-converting enzyme and angiotensin II type I receptor gene polymorphisms with extreme obesity in Polish individuals.

    Science.gov (United States)

    Pacholczyk, Marta; Ferenc, Tomasz; Kowalski, Jan; Adamczyk, Przemysław; Chojnowski, Jacek; Ponikowska, Irena

    2013-08-01

    There is strong evidence for the presence of a functional renin-angiotensin system in human adipose tissue. The aim of our study was to investigate the association of polymorphic variants of angiotensin-converting enzyme gene (ACE I/D) and angiotensin II type I receptor gene (AGTR1 A1166C) with extreme obesity and obesity-associated type 2 diabetes mellitus (T2DM) and to examine their combined effect on extremely obese patients. Overall, no significant associations were detected between ACE and AGTR1 gene polymorphisms and extreme obesity. However, extremely obese patients with T2DM showed an increased frequency of ACE II genotype compared with controls (pAGTR1 gene, regardless of the presence of T2DM. Moreover, the analysis of genetic polymorphisms demonstrated that ACE II and AGTR1 AC genotypes were most frequently observed in patients with extreme obesity and T2DM. On the basis of our results, we suggest that ACE II homozygosity may be a significant predictor of extreme obesity and T2DM and that the interaction between ACE and AGTR1 genes may be considered a predisposing factor for extreme obesity and extreme obesity-associated T2DM development.

  3. Direct Angiotensin II Type 2 Receptor Stimulation Ameliorates Insulin Resistance in Type 2 Diabetes Mice with PPARγ Activation

    DEFF Research Database (Denmark)

    Ohshima, Kousei; Mogi, Masaki; Jing, Fei

    2012-01-01

    The role of angiotensin II type 2 (AT(2)) receptor stimulation in the pathogenesis of insulin resistance is still unclear. Therefore we examined the possibility that direct AT(2) receptor stimulation by compound 21 (C21) might contribute to possible insulin-sensitizing/anti-diabetic effects in ty...... 2 diabetes (T2DM) with PPARγ activation, mainly focusing on adipose tissue....

  4. Increased expression of vascular endothelin type B and angiotensin type 1 receptors in patients with ischemic heart disease

    Directory of Open Access Journals (Sweden)

    Malmsjö Malin

    2009-08-01

    Full Text Available Abstract Background Endothelin-1 and angiotensin II are strong vasoconstrictors. Patients with ischemic heart disease have elevated plasma levels of endothelin-1 and angiotensin II and show increased vascular tone. The aim of the present study was to examine the endothelin and angiotensin II receptor expression in subcutaneous arteries from patients with different degrees of ischemic heart disease. Methods Subcutaneous arteries were obtained, by biopsy from the abdomen, from patients undergoing coronary artery bypass graft (CABG surgery because of ischemic heart disease (n = 15, patients with angina pectoris without established myocardial infarction (n = 15 and matched cardiovascular healthy controls (n = 15. Endothelin type A (ETA and type B (ETB, and angiotensin type 1 (AT1 and type 2 (AT2 receptors expression and function were examined using immunohistochemistry, Western blot and in vitro pharmacology. Results ETA and, to a lesser extent, ETB receptor staining was observed in the healthy vascular smooth muscle cells. The level of ETB receptor expression was higher in patients undergoing CABG surgery (250% ± 23%; P B receptor agonist sarafotoxin S6c, compared to healthy controls (P A receptors. AT1 and, to a lesser extent, AT2 receptor immunostaining was seen in the vascular smooth muscle cells. The level of AT1 receptor expression was higher in both the angina pectoris (128% ± 25%; P 1 receptor expression was confirmed by Western blotting. Myograph experiment did however not show any change in vasoconstriction to angiotensin II in CABG patients compared to healthy controls (P = n.s. Conclusion The results demonstrate, for the first time, upregulation of ETB and AT1 receptors in vascular smooth muscle cells in ischemic heart disease. These receptors may play a role in the pathophysiology of ischemic heart disease and could provide important targets for pharmaceutical interventions.

  5. Association of angiotensin converting enzyme and angiotensin type 2 receptor gene polymorphisms with renal damage in posterior urethral valves.

    Science.gov (United States)

    Laksmi, Narasimhan Kannan; Narasimhan, Kannan Laksmi; Khullar, Madhu; Madhu, Khullar; Kaur, Balpinder; Balpinder, Kaur; Ahuja, Monica; Monica, Ahuja; Mahajan, Jai Kumar; Kumar, Mahajan Jai; Mittal, Bhagwant Rai; Rai, Mittal Bhagwant; Bhattacharya, Anish; Anish, Bhattacharya; Medhi, Bikash; Bikash, Medhi

    2010-12-01

    To examine the association with renal damage in patients with posterior urethral valves (PUV) of two renin-angiotensin system gene polymorphisms: angiotensin converting enzyme insertion/deletion (ACE I/D) and angiotensin type 2 receptor (AT2R A1332G), PATIENTS AND METHODS: In 120 patients with PUV, after stabilization, transurethral fulguration or a Blocksom vesicostomy was performed. Records were reviewed for age at diagnosis, biochemical renal function at diagnosis, results of urine cultures, voiding cystourethrograms, radiologic, sonographic and nuclear medicine scan findings, and follow-up data. ACE I/D genotypes were determined by the polymerase chain reaction using allele specific primers. The frequency of the ACE DD genotype was significantly higher in patients with chronic kidney disease (P=0.02) and renal scarring (P=0.05). These genotypes were also associated with a statistically higher incidence of vesicoureteral reflux, diurnal incontinence, proteinuria and hypertension. A significantly higher frequency of the AT2R GG genotype was found in PUV patients as compared to healthy unrelated control subjects (P=0.001), and in PUV patients with scarring (P=0.02). The ACE DD and AT2R GG genotypes are associated with chronic kidney disease and scarring in PUV patients. The GG genotype incidence is higher among PUV patients compared to the control population, and further studies in this area may help understanding of the genetic basis of PUV. Copyright © 2010 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  6. Pharmacologic perspectives of functional selectivity by the angiotensin II type 1 receptor

    DEFF Research Database (Denmark)

    Aplin, Mark; Christensen, Gitte Lund; Hansen, Jakob Lerche

    2008-01-01

    The angiotensin II type 1 (AT(1)) receptor plays a key role in cardiovascular pathophysiology, and it is a major pharmacologic target in the treatment of many cardiovascular disorders. However, AT(1) receptor activation is also involved in adaptive responses to altered hemodynamic demands...... and to sudden injury occurring in the circulatory system. Hence, current drugs that block all AT(1) receptor actions most likely leave room for improvement. Recent developments show that two major signaling pathways used by the AT(1) receptor may be dissected by pharmacologic means. Key pathologic responses...

  7. Dopamine and angiotensin type 2 receptors cooperatively inhibit sodium transport in human renal proximal tubule cells.

    Science.gov (United States)

    Gildea, John J; Wang, Xiaoli; Shah, Neema; Tran, Hanh; Spinosa, Michael; Van Sciver, Robert; Sasaki, Midori; Yatabe, Junichi; Carey, Robert M; Jose, Pedro A; Felder, Robin A

    2012-08-01

    Little is known regarding how the kidney shifts from a sodium and water reclaiming state (antinatriuresis) to a state where sodium and water are eliminated (natriuresis). In human renal proximal tubule cells, sodium reabsorption is decreased by the dopamine D(1)-like receptors (D(1)R/D(5)R) and the angiotensin type 2 receptor (AT(2)R), whereas the angiotensin type 1 receptor increases sodium reabsorption. Aberrant control of these opposing systems is thought to lead to sodium retention and, subsequently, hypertension. We show that D(1)R/D(5)R stimulation increased plasma membrane AT(2)R 4-fold via a D(1)R-mediated, cAMP-coupled, and protein phosphatase 2A-dependent specific signaling pathway. D(1)R/D(5)R stimulation also reduced the ability of angiotensin II to stimulate phospho-extracellular signal-regulated kinase, an effect that was partially reversed by an AT(2)R antagonist. Fenoldopam did not increase AT(2)R recruitment in renal proximal tubule cells with D(1)Rs uncoupled from adenylyl cyclase, suggesting a role of cAMP in mediating these events. D(1)Rs and AT(2)Rs heterodimerized and cooperatively increased cAMP and cGMP production, protein phosphatase 2A activation, sodium-potassium-ATPase internalization, and sodium transport inhibition. These studies shed new light on the regulation of renal sodium transport by the dopaminergic and angiotensin systems and potential new therapeutic targets for selectively treating hypertension.

  8. ALDOSTERONE-INDUCED VASCULAR REMODELING AND ENDOTHELIAL DYSFUNCTION REQUIRE FUNCTIONAL ANGIOTENSIN TYPE 1a RECEPTORS

    OpenAIRE

    Briet, Marie; Barhoumi, Tlili; Mian, Muhammad Oneeb Rehman; Coelho, Suellen C.; Ouerd, Sofiane; Rautureau, Yohann; Coffman, Thomas M.; Paradis, Pierre; Ernesto L Schiffrin

    2016-01-01

    We investigated the role of angiotensin type 1a receptors (AGTR1a) in vascular injury induced by aldosterone activation of mineralocorticoid receptors (MR) in Agtr1a−/− and wild-type mice infused with aldosterone for 14 days while receiving 1% NaCl in drinking water. Aldosterone increased systolic blood pressure by ~30 mmHg in wild-type mice, and ~50 mmHg in Agtr1a−/− mice. Aldosterone induced aortic and small artery remodeling and impaired endothelium-dependent relaxation in wild-type mice, ...

  9. Effect of angiotensin II type 1 receptor blocker and angiotensin converting enzyme inhibitor on the intraocular growth factors and their receptors in streptozotocin-induced diabetic rats

    Directory of Open Access Journals (Sweden)

    Ik Soo Byon

    2017-06-01

    Full Text Available AIM: To investigate the effect of angiotensin II type 1 receptor blocker (ARB and angiotensin converting enzyme inhibitor (ACEI on intraocular growth factors and their receptors in streptozotocin-induced diabetic rats. METHODS: Forty Sprague-Dawley rats were divided into 4 groups: control, diabetes mellitus (DM, candesartan-treated DM, and enalapril-treated DM (each group, n=10. After the induction of DM by streptozotocin, candesartan [ARB, 5 mg/(kg·d] and enalapril [ACEI, 10 mg/(kg·d] were administered to rats orally for 4wk. Vascular endothelial growth factor (VEGF and angiotensin II (Ang II concentrations in the vitreous were measured using enzyme-linked immunosorbent assays, and VEGF receptor 2 and angiotensin II type 1 receptor (AT1R levels were assessed at week 4 by Western blotting. RESULTS: Vitreous Ang II levels were significantly higher in the DM group and candesartan-treated DM group than in the control (P=0.04 and 0.005, respectively. Vitreous AT1R increased significantly in DM compared to the other three groups (P<0.007. Candesartan-treated DM rats showed higher vitreal AT1R concentration than the enalapril-treated DM group and control (P<0.001 and P=0.005, respectively. No difference in vitreous Ang II and AT1R concentration was found between the enalapril-treated DM group and control. VEGF and its receptor were below the minimum detection limit in all 4 groups. CONCLUSION: Increased Ang II and AT1R in the hyperglycemic state indicate activated the intraocular renin-angiotensin system, which is inhibited more effectively by systemic ACEI than systemic ARB.

  10. Opposite regulation of brain angiotensin type 1 and type 2 receptors in cold-induced hypertension.

    Science.gov (United States)

    Peng, J F; Phillips, M I

    2001-03-02

    Rats exposed chronically to mild cold (5 degrees C/41 degrees F) develop hypertension. This cold-induced hypertension (CIH) is an environmentally induced, non-surgical, non-pharmacological and non-genetic model for studying hypertension in rats. The blood renin angiotensin system (RAS) appears to play a role in both initiating and maintaining the high blood pressure in CIH. The goal of the present study was to evaluate the role of brain angiotensin type 1 and type 2 receptors (AT1R and AT2R) in CIH. Sprague-Dawley adult male rats were used. Thirty-six rats were kept in a cold room at 5 degrees C and the other 36 were kept at 24 degrees C as controls. Systolic blood pressure (SBP) was recorded by tail cuff. The SBP was elevated in rats exposed to cold within 1 week (n=12, P>0.05), significantly increased at 3 weeks (Pcold-treated and the controls were sacrificed at 1, 3 and 5 weeks. Specific brain sections were removed, either for reverse transcription polymerase chain reaction (RT-PCR) to measure mRNA, or for autoradiography to measure receptor binding for AT1R and AT2R. The AT1R mRNA was increased significantly in hypothalamus and brainstem after the first week in cold-treated rats and was maintained throughout the time of exposure to cold (n=6, Pcold-treated rats after exposure to cold. The experiments show differential regulation of RAS components, AT1R and AT2R, in different brain areas in cold-exposed rats and provide evidence that up-regulated AT1R and down-regulated AT2R in different brain areas are involved in CIH. The opposing directions of expression of AT1R and AT2R suggest that they play counterbalancing roles in brain function.

  11. Molecular determinants of angiotensin II type 1 receptor functional selectivity

    DEFF Research Database (Denmark)

    Aplin, Mark; Bonde, Marie Mi; Hansen, Jakob Lerche

    2008-01-01

    -independent recruitment of beta-arrestin-scaffolded signalling complexes that activate protein kinase pathways. Different states of receptor activation with preference for individual downstream pathways (functional selectivity) have been demonstrated in mutational studies of the AT(1) receptor and by pharmacological...... that selective blockade of G protein actions and simultaneous activation of G protein-independent signalling will prove to be a feasible strategy for improved cardiovascular therapy. The pharmacological perspectives of functional selectivity by receptors, such as the AT(1) receptor, urge the elucidation...

  12. beta-Arrestin 1 and 2 stabilize the angiotensin II type I receptor in distinct high-affinity conformations

    DEFF Research Database (Denmark)

    Sanni, S J; Hansen, J T; Bonde, M M;

    2010-01-01

    The angiotensin II type 1 (AT(1)) receptor belongs to family A of 7 transmembrane (7TM) receptors. The receptor has important roles in the cardiovascular system and is commonly used as a drug target in cardiovascular diseases. Interaction of 7TM receptors with G proteins or beta-arrestins often...

  13. Heart Failure Therapeutics on the Basis of a Biased Ligand of the Angiotensin-2 Type 1 Receptor Rationale and Design of the BLAST-AHF Study (Biased Ligand of the Angiotensin Receptor Study in Acute Heart Failure)

    NARCIS (Netherlands)

    Felker, G. Michael; Butler, Javed; Collins, Sean P.; Cotter, Gad; Davison, Beth A.; Ezekowitz, Justin A.; Filippatos, Gerasimos; Levy, Phillip D.; Metra, Marco; Ponikowski, Piotr; Soergel, David G.; Teerlink, John R.; Violin, Jonathan D.; Voors, Adriaan A.; Pang, Peter S.

    2015-01-01

    The BLAST-AHF (Biased Ligand of the Angiotensin Receptor Study in Acute Heart Failure) study is designed to test the efficacy and safety of TRV027, a novel biased ligand of the angiotensin-2 type 1 receptor, in patients with acute heart failure (AHF). AHF remains a major public health problem, and n

  14. Nuclear angiotensin II type 2 (AT2) receptors are functionally linked to nitric oxide production.

    Science.gov (United States)

    Gwathmey, Tanya M; Shaltout, Hossam A; Pendergrass, Karl D; Pirro, Nancy T; Figueroa, Jorge P; Rose, James C; Diz, Debra I; Chappell, Mark C

    2009-06-01

    Expression of nuclear angiotensin II type 1 (AT(1)) receptors in rat kidney provides further support for the concept of an intracellular renin-angiotensin system. Thus we examined the cellular distribution of renal ANG II receptors in sheep to determine the existence and functional roles of intracellular ANG receptors in higher order species. Receptor binding was performed using the nonselective ANG II antagonist (125)I-[Sar(1),Thr(8)]-ANG II ((125)I-sarthran) with the AT(1) antagonist losartan (LOS) or the AT(2) antagonist PD123319 (PD) in isolated nuclei (NUC) and plasma membrane (PM) fractions obtained by differential centrifugation or density gradient separation. In both fetal and adult sheep kidney, PD competed for the majority of cortical NUC (> or =70%) and PM (> or =80%) sites while LOS competition predominated in medullary NUC (> or =75%) and PM (> or =70%). Immunodetection with an AT(2) antibody revealed a single approximately 42-kDa band in both NUC and PM extracts, suggesting a mature molecular form of the NUC receptor. Autoradiography for receptor subtypes localized AT(2) in the tubulointerstitium, AT(1) in the medulla and vasa recta, and both AT(1) and AT(2) in glomeruli. Loading of NUC with the fluorescent nitric oxide (NO) detector DAF showed increased NO production with ANG II (1 nM), which was abolished by PD and N-nitro-l-arginine methyl ester, but not LOS. Our studies demonstrate ANG II receptor subtypes are differentially expressed in ovine kidney, while nuclear AT(2) receptors are functionally linked to NO production. These findings provide further evidence of a functional intracellular renin-angiotensin system within the kidney, which may represent a therapeutic target for the regulation of blood pressure.

  15. The angiotensin II type 2 receptor agonist Compound 21 is protective in experimental diabetes-associated atherosclerosis

    DEFF Research Database (Denmark)

    Chow, Bryna S M; Koulis, Christine; Krishnaswamy, Pooja;

    2016-01-01

    AIMS/HYPOTHESIS: Angiotensin II is well-recognised to be a key mediator in driving the pathological events of diabetes-associated atherosclerosis via signalling through its angiotensin II type 1 receptor (AT1R) subtype. However, its actions via the angiotensin II type 2 receptor (AT2R) subtype...... are still poorly understood. This study is the first to investigate the role of the novel selective AT2R agonist, Compound 21 (C21) in an experimental model of diabetes-associated atherosclerosis (DAA). METHODS: Streptozotocin-induced diabetic Apoe-knockout mice were treated with vehicle (0.1 mol/l citrate...

  16. Increased expression of vascular endothelin type B and angiotensin type 1 receptors in patients with ischemic heart disease

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Edvinsson, Marie-Louise; Chen, Qingwen

    2009-01-01

    pectoris without established myocardial infarction (n = 15) and matched cardiovascular healthy controls (n = 15). Endothelin type A (ETA) and type B (ETB), and angiotensin type 1 (AT1) and type 2 (AT2) receptors expression and function were examined using immunohistochemistry, Western blot and in vitro...... in the healthy controls (100% +/- 28%). The data was confirmed by Western blotting. Arteries from CABG patients showed increased vasoconstriction upon administration of the selective ETB receptor agonist sarafotoxin S6c, compared to healthy controls (P ...%). The increased AT1 receptor expression was confirmed by Western blotting. Myograph experiment did however not show any change in vasoconstriction to angiotensin II in CABG patients compared to healthy controls (P = n.s). CONCLUSION: The results demonstrate, for the first time, upregulation of ETB and AT1...

  17. Influence of myocardial infarction on changes in the expression of angiotensin type 1 receptor in the rat prostate

    Directory of Open Access Journals (Sweden)

    Kamila Domińska

    2011-10-01

    Full Text Available Angiotensin II (AngII is the biologically active peptide of the renin-angiotensin system (RAS. Tissue- based, local RAS has been identified in the prostate, testis, epididymis and coagulating glands. Experimental and clinical studies have consistently shown that myocardial infarction (MI is associated with activation of the systemic RAS with increased concentration of angiotensin peptides in the blood and changes in expression of angiotensin receptors (AT. Changes in angiotensin receptors in the renal and cardiovascular system after MI are well recognized, but the effects of MI influence on changes in other tissue like the prostate gland are unknown. In the present study, we investigated the effect of myocardial infarction on angiotensin receptor protein and mRNA expression in the rat prostate gland. MI model was established in Wistar rats by ligating the left coronary artery (modified Selye method. The levels of AT1a-b and AT2 receptor mRNAs and proteins were measured in the rat prostate. Our study demonstrates tissue-specific changes in AT1a-b and AT2 receptor expression after myocardial infarction. The results show that MI has a strong influence on the expression of angiotensin receptor type AT1 in the prostate at the protein and mRNA level. (Folia Histochemica et Cytobiologica 2011, Vol. 49, No. 3, 497–503

  18. An angiotensin II type 1 receptor activation switch patch revealed through evolutionary trace analysis

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Yao, Rong; Ma, Jian-Nong;

    2010-01-01

    in the cytoplasmic parts of TM2, TM3, and TM6 to form an activation switch that is common to all family A 7TM receptors. We tested this hypothesis in the rat Angiotensin II (Ang II) type 1a (AT1a) receptor. The receptor has important roles in the cardiovascular system, but has also frequently been applied as a model...... for 7TM receptor activation and signaling. Six mutations: F66A, L67R, L70R, L119R, D125A, and I245F were targeted to the putative switch and assayed for changes in activation state by their ligand binding, signaling, and trafficking properties. All but one receptor mutant (that was not expressed well...

  19. Direct stimulation of angiotensin II type 2 receptor enhances spatial memory

    DEFF Research Database (Denmark)

    Jing, Fei; Mogi, Masaki; Sakata, Akiko

    2012-01-01

    We examined the possibility that direct stimulation of the angiotensin II type 2 (AT(2)) receptor by a newly generated direct AT(2) receptor agonist, Compound 21 (C21), enhances cognitive function. Treatment with C21 intraperitoneal injection for 2 weeks significantly enhanced cognitive function...... evaluated by the Morris water maze test in C57BL6 mice, but this effect was not observed in AT(2) receptor-deficient mice. However, C21-induced cognitive enhancement in C57BL6 mice was attenuated by coadministration of icatibant, a bradykinin B(2) receptor antagonist. Administration of C21 dose dependently...... cognitive decline in this model. These results suggest that a direct AT(2) receptor agonist, C21, enhances cognitive function at least owing to an increase in CBF, enhancement of f-EPSP, and neurite outgrowth in hippocampal neurons....

  20. Angiotensin-II mediates ACE2 Internalization and Degradation through an Angiotensin-II type I receptor-dependent mechanism

    OpenAIRE

    Deshotels, Matthew R.; Xia, Huijing; Lazartigues, Eric; Filipeanu, Catalin M.

    2014-01-01

    Angiotensin Converting Enzyme type 2 (ACE2) is a pivotal component of the renin-angiotensin system, promoting the conversion of Angiotensin (Ang)-II to Ang-(1-7). We previously reported that decreased ACE2 expression and activity contribute to the development of Ang-II-mediated hypertension in mice. The present study aimed to investigate the mechanisms involved in ACE2 down-regulation during neurogenic hypertension. In ACE2-transfected Neuro-2A cells, Ang-II treatment resulted in a significan...

  1. Angiotensin-converting enzyme inhibitors reduce albuminuria more than angiotensin receptor blockers in patients with type 2 diabetes.

    Science.gov (United States)

    Al-Sayed, Nasreen A; Gao, Tianming; Wells, Brian J; Yu, Changhong; Zimmerman, Robert S

    2013-01-01

    This study retrospectively compared the effects of angiotensin-converting enzyme inhibitors (ACEIs) versus angiotensin receptor blockers (ARBs) as classes with respect to overall mortality and cardiovascular and renal events in patients with type 2 diabetes. An electronic database of medical records was reviewed. A total of 16,489 patients with type 2 diabetes were enrolled and divided into ACEI (n = 12,351) or ARB (n = 4,138) groups. Baseline patient characteristics were compared using univariable analysis. A chi-square test was used for categorical outcomes, and the propensity class was calculated using multivariable logistic regression. Survival analysis was performed to evaluate the effect of ACEIs/ARBs on overall survival, coronary artery disease (CAD), and renal events via Cox regression analysis, adjusting for propensity class and baseline variables. All statistical analyses were conducted using R 2.15.1 software. No significant differences in overall survival (P = .16) and CAD (P = .81) events were observed between groups. With respect to renal events, ARBs increased the risk of creatinine doubling compared with ACEIs, but the difference was not significant (hazard ratio [HR], 1.207; 95% confidence interval [CI], 0.921-1.583; P = .173). Patients who received ARBs had a significantly higher rate of albuminuria than patients who received ACEIs (HR, 1.303; 95% CI, 1.053-1.612; P = .015). The early effects of ACEIs and ARBs on albuminuria outcome seem to be different in type 2 diabetes, favoring the use of ACEIs. A well-designed prospective study is warranted to evaluate this finding.

  2. Biased signaling of the angiotensin II type 1 receptor can be mediated through distinct mechanisms

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Hansen, Jonas Tind; Sanni, Samra Joke;

    2010-01-01

    molecular mechanisms remain largely unresolved. For instance, it is unclear whether such selective G protein-uncoupling is caused by a lack of ability to interact with G proteins or rather by an increased ability of the receptor to recruit β-arrestins. Since uncoupling of G proteins by increased ability......Seven transmembrane receptors (7TMRs) can adopt different active conformations facilitating a selective activation of either G protein or β-arrestin-dependent signaling pathways. This represents an opportunity for development of novel therapeutics targeting selective biological effects of a given...... receptor. Several studies on pathway separation have been performed, many of these on the Angiotensin II type 1 receptor (AT1R). It has been shown that certain ligands or mutations facilitate internalization and/or recruitment of β-arrestins without activation of G proteins. However, the underlying...

  3. Biased signaling of the angiotensin II type 1 receptor can be mediated through distinct mechanisms

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Hansen, Jonas Tind; Sanni, Samra Joke;

    2010-01-01

    molecular mechanisms remain largely unresolved. For instance, it is unclear whether such selective G protein-uncoupling is caused by a lack of ability to interact with G proteins or rather by an increased ability of the receptor to recruit ß-arrestins. Since uncoupling of G proteins by increased ability......Seven transmembrane receptors (7TMRs) can adopt different active conformations facilitating a selective activation of either G protein or ß-arrestin-dependent signaling pathways. This represents an opportunity for development of novel therapeutics targeting selective biological effects of a given...... receptor. Several studies on pathway separation have been performed, many of these on the Angiotensin II type 1 receptor (AT1R). It has been shown that certain ligands or mutations facilitate internalization and/or recruitment of ß-arrestins without activation of G proteins. However, the underlying...

  4. An Angiotensin II type 1 receptor activation switch patch revealed through Evolutionary Trace analysis

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Yao, Rong; Ma, Jian-Nong

    2010-01-01

    in the cytoplasmic parts of TM2, TM3, and TM6 to form an activation switch that is common to all family A 7TM receptors. We tested this hypothesis in the rat Angiotensin II (Ang II) type 1a (AT1a) receptor. The receptor has important roles in the cardiovascular system, but has also frequently been applied as a model......) displayed phenotypes associated with changed activation state, such as increased agonist affinity or basal activity, promiscuous activation, or constitutive internalization highlighting the importance of testing different signaling pathways. We conclude that this evolutionary important patch mediates...... to be completely resolved. Evolutionary Trace (ET) analysis is a computational method, which identifies clusters of functionally important residues by integrating information on evolutionary important residue variations with receptor structure. Combined with known mutational data, ET predicted a patch of residues...

  5. Effect of angiotensin Ⅱ and angiotensintype 1 receptor antagonist on the proliferation,contraction and collagen synthesis in rat hepatic stellate cells

    Institute of Scientific and Technical Information of China (English)

    LIU Jun; GONG Hao; ZHANG Zhong-tao; WANG Yu

    2008-01-01

    Background Angiotensin Ⅱ(Ang Ⅱ)is a very important vasoactive peptide that acts upon hepatic stellate cells(HSCs),which are major effector cells in hepatic cirrhosis and portal hypertension.The present study was aimed to investigate the effects of Ang Ⅱ and angiotensintype 1 receptor antagonist(AT1RA)on the proliferation,contraction and collagen synthesis in HSCs.Methods HSC-T6 rat hepatic stellate cell Iine was studied.The proliferation of the HSC cells was evaluated by MTT colorimetric assay while HSC DNA synthesis was measured by3 H-thymidine incorporation.The effects of angiotensin Ⅱ and AT1 RA on HSCs contraction were studied by analVSIs of the contraction of the collagen Iattice.CelI culture media were analyzed by RT-PCR to detect secretion of collagen Ⅰ(Col Ⅰ),collagen Ⅲ(Col Ⅲ)and transforming growth factor β1 (TGF-β1)by enzyme Iinked Immunosorbent assay.HSC was harvested to measure collagen Ⅰ,collagen Ⅲ and tissue inhibitor of metalloproteinase-1(TIMP-1)mRNA expression.Results Ang Ⅱ((1 x10-10-1×10-4)mol/L)stimulated DNA synthesis and proliferation in HSCs compared with untreated control cells.AT1 RA inhibited angiotensin Ⅱ induced proliferation of HSCs.A Iinear increase in the contractive area of collagen lattice correlated with the concentration of angiotensin Ⅱ(1×10-9-1×10-5mol/L)and with time over 48 hours.ATlRA blocks angiotensin Ⅱ induced contraction of collagen Iattice.Coll,Col Ⅲ and TGF-β1 levels of the Ang Ⅱ group were higher than those of control group and this increase was downregulated by AT1RA.The mRNA expressions of ColⅠ,CoI Ⅲ and TIMP-1 were higher in HSCs from the Ang Ⅱ group than the control group and downregulated by AT1RA.Conclusions Angiotensin Ⅱ increased DNA synthesis and proliferation of HSCs in a dose-dependent manner,stimulated the contraction of HSCs dose-and time-dependently.Angiotensin also promoted excretion of Col Ⅰ,ColⅢand TGF-β1 Ievels and stimulated Col Ⅰ,Col Ⅲ and

  6. The effect of serum angiotensin II and angiotensin II type 1 receptor ...

    African Journals Online (AJOL)

    Ehab

    2012-06-18

    Jun 18, 2012 ... frequency of AT1 receptor CC genotype among a group of Egyptian patients with ..... reported in SLE patients.2,3,15 ACE catalyses the formation of Ang II .... Bombardier C, Gladman DD, Urowitz MB, Caron. D, Chang CH.

  7. Targeting angiotensin II type 2 receptor pathways to treat neuropathic pain and inflammatory pain.

    Science.gov (United States)

    Smith, Maree T; Muralidharan, Arjun

    2015-01-01

    Neuropathic pain and chronic inflammatory pain are large unmet medical needs. Over the past two decades, numerous 'pain targets' have been identified for analgesic drug discovery. Despite promising results in rodent pain models, many compounds modulating such targets lacked efficacy in clinical trials. An exception is oral EMA401, a small-molecule angiotensin II type 2 receptor (AT2R) antagonist. Herein, angiotensin II/AT2R signaling-induced hyperexcitability and abnormal sprouting of cultured dorsal root ganglion neurons, together with radioligand binding, pharmacokinetics, analgesic efficacy and mode of action of small-molecule AT2R antagonists in rodent models of peripheral neuropathic and chronic inflammatory pain, are reviewed. The findings of a successful Phase IIa clinical trial of EMA401 in patients with neuropathic pain are presented in brief. The functional importance of angiotensin II/AT2R signaling has remained enigmatic for decades, and there are no clinically available medications that target the AT2R. However, on the basis of preclinical findings and recent clinical trial data showing that the peripherally restricted, small-molecule AT2R antagonist, EMA401, successfully alleviated neuropathic pain in a Phase II clinical trial, the AT2R is receiving considerable attention as a new therapeutic target with human validation for the relief of peripheral neuropathic and chronic inflammatory pain conditions.

  8. Efficacy of angiotensin II type 1 receptor blockade on reperfusion-induced arrhythmias and mortality early after myocardial infarction is increased in transgenic rats with cardiac angiotensin II type 1 overexpression

    NARCIS (Netherlands)

    de Boer, RA; van Geel, PP; Pinto, YM; Suurmeijer, AJH; Crijns, HJGM; van Gilst, WH; van Veldhuisen, DJ

    2002-01-01

    Angiotensin II induces ischemia/reperfusion (I/R)-induced arrhythmias and blockade of the angiotensin II type I receptor (AT1R) may therefore be beneficial in preventing arrhythmias and decreasing mortality after myocardial infarction (MI). Because the AT1R is upregulated after myocardial ischemia,

  9. Activation Induces Structural Changes in the Liganded Angiotensin II Type 1 Receptor*

    Science.gov (United States)

    Clément, Martin; Cabana, Jérôme; Holleran, Brian J.; Leduc, Richard; Guillemette, Gaétan; Lavigne, Pierre; Escher, Emanuel

    2009-01-01

    The octapeptide hormone angiotensin II (AngII) binds to and activates the human angiotensin II type 1 receptor (hAT1) of the G protein-coupled receptor class A family. Several activation mechanisms have been proposed for this family, but they have not yet been experimentally validated. We previously used the methionine proximity assay to show that 11 residues in transmembrane domain (TMD) III, VI, and VII of the hAT1 receptor reside in close proximity to the C-terminal residue of AngII. With the exception of a single change in TMD VI, the same contacts are present on N111G-hAT1, a constitutively active mutant; this N111G-hAT1 is a model for the active form of the receptor. In this study, two series of 53 individual methionine mutations were constructed in TMD I, II, IV, and V on both receptor forms. The mutants were photolabeled with a neutral antagonist, 125I-[Sar1,p-benzoyl-l-Phe8]AngII, and the resulting complexes were digested with cyanogen bromide. Although no new contacts were found for the hAT1 mutants, two were found in the constitutively active mutants, Phe-77 in TMD II and Asn-200 in TMD V. To our knowledge, this is the first time that a direct ligand contact with TMD II and TMD V has been reported. These contact point differences were used to identify the structural changes between the WT-hAT1 and N111G-hAT1 complexes through homology-based modeling and restrained molecular dynamics. The model generated revealed an important structural rearrangement of several TMDs from the basal to the activated form in the WT-hAT1 receptor. PMID:19635801

  10. Reassessment of the unique mode of binding between angiotensin II type 1 receptor and their blockers.

    Directory of Open Access Journals (Sweden)

    Shin-Ichiro Miura

    Full Text Available While the molecular structures of angiotensin II (Ang II type 1 (AT1 receptor blockers (ARBs are very similar, they are also slightly different. Although each ARB has been shown to exhibit a unique mode of binding to AT1 receptor, different positions of the AT1 receptor have been analyzed and computational modeling has been performed using different crystal structures for the receptor as a template and different kinds of software. Therefore, we systematically analyzed the critical positions of the AT1 receptor, Tyr(113, Tyr(184, Lys(199, His(256 and Gln(257 using a mutagenesis study, and subsequently performed computational modeling of the binding of ARBs to AT1 receptor using CXCR4 receptor as a new template and a single version of software. The interactions between Tyr(113 in the AT1 receptor and the hydroxyl group of olmesartan, between Lys(199 and carboxyl or tetrazole groups, and between His(256 or Gln(257 and the tetrazole group were studied. The common structure, a tetrazole group, of most ARBs similarly bind to Lys(199, His(256 and Gln(257 of AT1 receptor. Lys(199 in the AT1 receptor binds to the carboxyl group of EXP3174, candesartan and azilsartan, whereas oxygen in the amidecarbonyl group of valsartan may bind to Lys(199. The benzimidazole portion of telmisartan may bind to a lipophilic pocket that includes Tyr(113. On the other hand, the n-butyl group of irbesartan may bind to Tyr(113. In conclusion, we confirmed that the slightly different structures of ARBs may be critical for binding to AT1 receptor and for the formation of unique modes of binding.

  11. Angiotensin II Type 1 Receptor-Mediated Electrical Remodeling in Mouse Cardiac Myocytes.

    Directory of Open Access Journals (Sweden)

    Jeremy Kim

    Full Text Available We recently characterized an autocrine renin angiotensin system (RAS in canine heart. Activation of Angiotensin II Type 1 Receptors (AT1Rs induced electrical remodeling, including inhibition of the transient outward potassium current Ito, prolongation of the action potential (AP, increased calcium entry and increased contractility. Electrical properties of the mouse heart are very different from those of dog heart, but if a similar system existed in mouse, it could be uniquely studied through genetic manipulations. To investigate the presence of a RAS in mouse, we measured APs and Ito in isolated myocytes. Application of angiotensin II (A2 for 2 or more hours reduced Ito magnitude, without affecting voltage dependence, and prolonged APs in a dose-dependent manner. Based on dose-inhibition curves, the fast and slow components of Ito (Ito,fast and IK,slow appeared to be coherently regulated by [A2], with 50% inhibition at an A2 concentration of about 400 nM. This very high K0.5 is inconsistent with systemic A2 effects, but is consistent with an autocrine RAS in mouse heart. Pre-application of the microtubule destabilizing agent colchicine eliminated A2 effects on Ito and AP duration, suggesting these effects depend on intracellular trafficking. Application of the biased agonist SII ([Sar1-Ile4-Ile8]A2, which stimulates receptor internalization without G protein activation, caused Ito reduction and AP prolongation similar to A2-induced changes. These data demonstrate AT1R mediated regulation of Ito in mouse heart. Moreover, all measured properties parallel those measured in dog heart, suggesting an autocrine RAS may be a fundamental feedback system that is present across species.

  12. Increased expression of vascular endothelin type B and angiotensin type 1 receptors in patients with ischemic heart disease

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Edvinsson, Lars; Chen, Qingwen

    2009-01-01

    expression in subcutaneous arteries from patients with different degrees of ischemic heart disease. METHODS: Subcutaneous arteries were obtained, by biopsy from the abdomen, from patients undergoing coronary artery bypass graft (CABG) surgery because of ischemic heart disease (n = 15), patients with angina...... pectoris without established myocardial infarction (n = 15) and matched cardiovascular healthy controls (n = 15). Endothelin type A (ETA) and type B (ETB), and angiotensin type 1 (AT1) and type 2 (AT2) receptors expression and function were examined using immunohistochemistry, Western blot and in vitro...... in the healthy controls (100% +/- 28%). The data was confirmed by Western blotting. Arteries from CABG patients showed increased vasoconstriction upon administration of the selective ETB receptor agonist sarafotoxin S6c, compared to healthy controls (P difference was found for the ETA receptors...

  13. Antiangiogenic effect of angiotensin II type 2 receptor in ischemia-induced angiogenesis in mice hindlimb.

    Science.gov (United States)

    Silvestre, Jean-Sébastien; Tamarat, Radia; Senbonmatsu, Takaaki; Icchiki, Toshihiro; Ebrahimian, Teni; Iglarz, Marc; Besnard, Sandrine; Duriez, Micheline; Inagami, Tadashi; Lévy, Bernard I

    2002-05-31

    This study examined the potential role of angiotensin type 2 (AT(2)) receptor on angiogenesis in a model of surgically induced hindlimb ischemia. Ischemia was produced by femoral artery ligature in both wild-type and AT(2) gene-deleted mice (Agtr2(-)/Y). After 28 days, angiogenesis was quantitated by microangiography, capillary density measurement, and laser Doppler perfusion imaging. Protein levels of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), Bax, and Bcl-2 were determined by Western blot analysis in hindlimbs. The AT(2) mRNA level (assessed by semiquantitative RT-PCR) was increased in the ischemic hindlimb of wild-type mice. Angiographic vessel density and laser Doppler perfusion data showed significant improvement in ischemic/nonischemic leg ratio, 1.9- and 1.7-fold, respectively, in Agtr2(-)/Y mice compared with controls. In ischemic leg of Agtr2(-)/Y mice, revascularization was associated with an increase in the antiapoptotic protein content, Bcl-2 (211% of basal), and a decrease (60% of basal) in the number of cell death, determined by TUNEL method. Angiotensin II treatment (0.3 mg/kg per day) raised angiogenic score, blood perfusion, and both VEGF and eNOS protein content in ischemic leg of wild-type control but did not modulate the enhanced angiogenic response observed in untreated Agtr2(-)/Y mice. Finally, immunohistochemistry analysis revealed that VEGF was mainly localized to myocyte, whereas eNOS-positive staining was mainly observed in the capillary of ischemic leg of both wild-type and AT(2)-deficient mice. This study demonstrates for the first time that the AT(2) receptor subtype may negatively modulate ischemia-induced angiogenesis through an activation of the apoptotic process.

  14. Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xianwei, E-mail: XWang2@UAMS.edu; Lu, Jingjun; Khaidakov, Magomed; Mitra, Sona; Ding, Zufeng; Raina, Sameer; Goyal, Tanu; Mehta, Jawahar L., E-mail: MehtaJL@UAMS.edu

    2012-03-15

    Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiac fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22{sup phox}, p47{sup phox}, p67{sup phox}, NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H{sub 2}O{sub 2}. Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety. -- Highlights: ► Aspirin in therapeutic concentrations decreases mouse cardiac

  15. Angiotensin II type 1 receptor (A1166C gene polymorphism and essential hypertension in Egyptian population

    Directory of Open Access Journals (Sweden)

    Marium M. Shamaa

    2016-09-01

    Full Text Available The pathogenesis of essential hypertension (EH is affected by genetic and environmental factors. Mutations in hypertension-related genes can affect blood pressure (BP via alteration of salt and water reabsorption by the nephron. The genes of the renin-angiotensin system (RAS have been extensively studied because of the well documented role of this system in the control of BP. It has been previously shown that Angiotensin II type 1 receptor (ATR1 gene polymorphism could be associated with increased risk of EH. So, in the current study, we evaluated the frequency of ATR1 (A1166C polymorphism in relation to EH in a group of Egyptian population. The study population included 83 hypertensive patients and 60 age and sex matched healthy control subjects. Restriction fragment length polymorphism – Polymerase chain reaction (RFLP – PCR was used for the analysis of A1166C polymorphism of ATR1 genes in peripheral blood samples of all patients and controls. The results revealed that there was a positive risk of developing EH when having the T allele whether in homozygous or heterozygous state. From this work, it was concluded that there was an association between ATR1 (A1166C gene polymorphism and the risk of developing EH.

  16. POLYMORPHISM OF ANGIOTENSINTYPE 1 RECEPTOR GENE IN ELDERLY PATIENTS WITH ESSENTIAL HYPERTENSION

    Institute of Scientific and Technical Information of China (English)

    方宁远; 张怡; 陆惠华; 郑迪辉; 邬亦贤; 郑道声

    2003-01-01

    Objective To detect the A/C1166 polymorphism of angiotensintype-1 receptor (AT1 R) gene in essential hypertensive elderly.MethodsThe A/C1166 polymorphism of AT1 R gene was assessed by polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) in a case control study of 87 essential hypertensive elders (EH) and 55 normotensive elders (NT).ResultsThe genotype frequencies of AA, AC, CC were 0.805, 0.161, 0.034 in EH group and 0.927, 0.073, 0.000 in NT group respectively. The frequency of C1166 allele was higher in EH group (0.115) than in NT group (0.036)(P<0.05).ConclusionThe results indicate that A/C1166 polymorphism of AT1 R gene may be associated with essential hypertension in elderly.

  17. Effectiveness of Angiotensin II Receptor Antagonists in a Cohort of Dutch Patients With Type 2 Diabetes Mellitus (ZODIAC-14)

    NARCIS (Netherlands)

    van Hateren, Kornelis J. J.; Landman, Gijs W. D.; Groenier, Klaas H.; Bilo, Henk J. G.; Kleefstra, Nanne

    OBJECTIVE: There is limited evidence with respect to the between-group effects of various angiotensin receptor blockers (ARBs) on blood pressure and albuminuria in patients with type 2 diabetes mellitus. Therefore, we aimed to investigate the effects of differing ARBs on systolic blood pressure

  18. Effectiveness of Angiotensin II Receptor Antagonists in a Cohort of Dutch Patients With Type 2 Diabetes Mellitus (ZODIAC-14)

    NARCIS (Netherlands)

    van Hateren, Kornelis J. J.; Landman, Gijs W. D.; Groenier, Klaas H.; Bilo, Henk J. G.; Kleefstra, Nanne

    2015-01-01

    OBJECTIVE: There is limited evidence with respect to the between-group effects of various angiotensin receptor blockers (ARBs) on blood pressure and albuminuria in patients with type 2 diabetes mellitus. Therefore, we aimed to investigate the effects of differing ARBs on systolic blood pressure (SBP

  19. Increased angiotensin II type 1 receptor expression in temporal arteries from patients with giant cell arteritis

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Malmsjö, Malin; Andersson, Christina

    2009-01-01

    PURPOSE: Currently, giant cell arteritis (GCA) is primarily treated with corticosteroids or immunomodulating agents, but there is interest in identifying other noncorticosteroid alternatives. Similarities exist in the injury pathways between GCA and atherosclerosis. Angiotensin II is a vasoactive...... DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article....... with antibodies for the AT(2) receptor was similar in the patients with GCA and in controls. CONCLUSIONS: These results suggest that AT(1) receptors play a role in the development of GCA. Inhibition of the angiotensin system may thus provide a noncorticosteroid alternative for the treatment of GCA. FINANCIAL...

  20. Aldosterone-induced brain MAPK signaling and sympathetic excitation are angiotensin II type-1 receptor dependent.

    Science.gov (United States)

    Zhang, Zhi-Hua; Yu, Yang; Wei, Shun-Guang; Felder, Robert B

    2012-02-01

    Angiotensin II (ANG II)-induced mitogen-activated protein kinase (MAPK) signaling upregulates angiotensin II type-1 receptors (AT(1)R) in hypothalamic paraventricular nucleus (PVN) and contributes to AT(1)R-mediated sympathetic excitation in heart failure. Aldosterone has similar effects to increase AT(1)R expression in the PVN and sympathetic drive. The present study was undertaken to determine whether aldosterone also activates the sympathetic nervous system via MAPK signaling and, if so, whether its effect is independent of ANG II and AT(1)R. In anesthetized rats, a 4-h intravenous infusion of aldosterone induced increases (P < 0.05) in phosphorylated (p-) p44/42 MAPK in PVN, PVN neuronal excitation, renal sympathetic nerve activity (RSNA), mean blood pressure (MBP), and heart rate (HR). Intracerebroventricular or bilateral PVN microinjection of the p44/42 MAPK inhibitor PD-98059 reduced the aldosterone-induced RSNA, HR, and MBP responses. Intracerebroventricular pretreatment (5 days earlier) with pooled small interfering RNAs targeting p44/42 MAPK reduced total and p-p44/42 MAPK, aldosterone-induced c-Fos expression in the PVN, and the aldosterone-induced increases in RSNA, HR, and MBP. Intracerebroventricular infusion of either the mineralocorticoid receptor antagonist RU-28318 or the AT(1)R antagonist losartan blocked aldosterone-induced phosphorylation of p44/42 MAPK and prevented the increases in RSNA, HR, and MBP. These data suggest that aldosterone-induced sympathetic excitation depends upon that AT(1)R-induced MAPK signaling in the brain. The short time course of this interaction suggests a nongenomic mechanism, perhaps via an aldosterone-induced transactivation of the AT(1)R as described in peripheral tissues.

  1. Dietary sodium intake regulates angiotensin II type 1, mineralocorticoid receptor, and associated signaling proteins in heart.

    Science.gov (United States)

    Ricchiuti, Vincent; Lapointe, Nathalie; Pojoga, Luminita; Yao, Tham; Tran, Loc; Williams, Gordon H; Adler, Gail K

    2011-10-01

    Liberal or high-sodium (HS) intake, in conjunction with an activated renin-angiotensin-aldosterone system, increases cardiovascular (CV) damage. We tested the hypothesis that sodium intake regulates the type 1 angiotensin II receptor (AT(1)R), mineralocorticoid receptor (MR), and associated signaling pathways in heart tissue from healthy rodents. HS (1.6% Na(+)) and low-sodium (LS; 0.02% Na(+)) rat chow was fed to male healthy Wistar rats (n=7 animals per group). Protein levels were assessed by western blot and immunoprecipitation analysis. Fractionation studies showed that MR, AT(1)R, caveolin-3 (CAV-3), and CAV-1 were located in both cytoplasmic and membrane fractions. In healthy rats, consumption of an LS versus a HS diet led to decreased cardiac levels of AT(1)R and MR. Decreased sodium intake was also associated with decreased cardiac levels of CAV-1 and CAV-3, decreased immunoprecipitation of AT(1)R-CAV-3 and MR-CAV-3 complexes, but increased immunoprecipitation of AT(1)R/MR complexes. Furthermore, decreased sodium intake was associated with decreased cardiac extracellular signal-regulated kinase (ERK), phosphorylated ERK (pERK), and pERK/ERK ratio; increased cardiac striatin; decreased endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (peNOS), but increased peNOS/eNOS ratio; and decreased cardiac plasminogen activator inhibitor-1. Dietary sodium restriction has beneficial effects on the cardiac expression of factors associated with CV injury. These changes may play a role in the cardioprotective effects of dietary sodium restriction.

  2. Vascular angiotensin II type 2 receptor attenuates atherosclerosis via a kinin/NO-dependent mechanism.

    Science.gov (United States)

    Takata, Hiroki; Yamada, Hiroyuki; Kawahito, Hiroyuki; Kishida, Sou; Irie, Daisuke; Kato, Taku; Wakana, Noriyuki; Miyagawa, Sonoko; Fukui, Kensuke; Matsubara, Hiroaki

    2015-06-01

    The angiotensin II (Ang II) type 1 receptor exerts pro-atherogenic action by augmenting oxidative stress, whereas the Ang II type 2 receptor (AT2)-mediated effect on atherosclerosis remains controversial. AT2 transgenic (AT2-Tg) mice, which overexpress AT2 in their vascular smooth muscle cells, were crossed with apoE-deficient (apoE(-/-)) mice to generate AT2 transgenic apoE(-/-) mice (AT2-Tg/apoE(-/-)). A subpressor dose of Ang II infusion exaggerated atherosclerosis development in apoE(-/-) mice, which was markedly suppressed in AT2-Tg/apoE(-/-) mice. Inhibitors of nitric oxide (NO) synthase (L-NAME) or bradykinin type 2 receptor completely abolished AT2-mediated anti-atherogenic actions. The vascular cell adhesion molecule-1 expression levels and degree of monocyte/macrophage accumulation in the intima were also considerably reduced in AT2-Tg/apoE(-/-) mice; these phenomena were completely reversed by L-NAME treatment. Ang II infusion significantly enhanced the accumulation of dihydroethidium-positive mononuclear cells in the intima and mRNA expression levels of Nox2, a phagocytic cell-type NADPH oxidase subunit in apoE(-/-) mice, which was completely inhibited in AT2-Tg/apoE(-/-) mice. Vascular AT2 stimulation exerts anti-atherogenic actions in an endothelial kinin/NO-dependent manner, and its anti-oxidative effect is likely to be exerted by inhibiting the accumulation of superoxide-producing mononuclear leukocytes. © The Author(s) 2013.

  3. Rational drug design and synthesis of molecules targeting the angiotensin II type 1 and type 2 receptors.

    Science.gov (United States)

    Kellici, Tahsin F; Tzakos, Andreas G; Mavromoustakos, Thomas

    2015-03-02

    The angiotensin II (Ang II) type 1 and type 2 receptors (AT1R and AT2R) orchestrate an array of biological processes that regulate human health. Aberrant function of these receptors triggers pathophysiological responses that can ultimately lead to death. Therefore, it is important to design and synthesize compounds that affect beneficially these two receptors. Cardiovascular disease, which is attributed to the overactivation of the vasoactive peptide hormone Αng II, can now be treated with commercial AT1R antagonists. Herein, recent achievements in rational drug design and synthesis of molecules acting on the two AT receptors are reviewed. Quantitative structure activity relationships (QSAR) and molecular modeling on the two receptors aim to assist the search for new active compounds. As AT1R and AT2R are GPCRs and drug action is localized in the transmembrane region the role of membrane bilayers is exploited. The future perspectives in this field are outlined. Tremendous progress in the field is expected if the two receptors are crystallized, as this will assist the structure based screening of the chemical space and lead to new potent therapeutic agents in cardiovascular and other diseases.

  4. BMP type I receptor ALK2 is required for angiotensin II-induced cardiac hypertrophy

    Science.gov (United States)

    Spagnolli, Ester; Ernande, Laura; Thoonen, Robrecht; Kolodziej, Starsha A.; Leyton, Patricio A.; Cheng, Juan; Tainsh, Robert E. T.; Mayeur, Claire; Rhee, David K.; Wu, Mei. X.; Scherrer-Crosbie, Marielle; Buys, Emmanuel S.; Zapol, Warren M.; Bloch, Kenneth D.; Bloch, Donald B.

    2016-01-01

    Bone morphogenetic protein (BMP) signaling contributes to the development of cardiac hypertrophy. However, the identity of the BMP type I receptor involved in cardiac hypertrophy and the underlying molecular mechanisms are poorly understood. By using quantitative PCR and immunoblotting, we demonstrated that BMP signaling increased during phenylephrine-induced hypertrophy in cultured neonatal rat cardiomyocytes (NRCs), as evidenced by increased phosphorylation of Smads 1 and 5 and induction of Id1 gene expression. Inhibition of BMP signaling with LDN193189 or noggin, and silencing of Smad 1 or 4 using small interfering RNA diminished the ability of phenylephrine to induce hypertrophy in NRCs. Conversely, activation of BMP signaling with BMP2 or BMP4 induced hypertrophy in NRCs. Luciferase reporter assay further showed that BMP2 or BMP4 treatment of NRCs repressed atrogin-1 gene expression concomitant with an increase in calcineurin protein levels and enhanced activity of nuclear factor of activated T cells, providing a mechanism by which BMP signaling contributes to cardiac hypertrophy. In a model of cardiac hypertrophy, C57BL/6 mice treated with angiotensin II (A2) had increased BMP signaling in the left ventricle. Treatment with LDN193189 attenuated A2-induced cardiac hypertrophy and collagen deposition in left ventricles. Cardiomyocyte-specific deletion of BMP type I receptor ALK2 (activin-like kinase 2), but not ALK1 or ALK3, inhibited BMP signaling and mitigated A2-induced cardiac hypertrophy and left ventricular fibrosis in mice. The results suggest that BMP signaling upregulates the calcineurin/nuclear factor of activated T cell pathway via BMP type I receptor ALK2, contributing to cardiac hypertrophy and fibrosis. PMID:26873969

  5. BMP type I receptor ALK2 is required for angiotensin II-induced cardiac hypertrophy.

    Science.gov (United States)

    Shahid, Mohd; Spagnolli, Ester; Ernande, Laura; Thoonen, Robrecht; Kolodziej, Starsha A; Leyton, Patricio A; Cheng, Juan; Tainsh, Robert E T; Mayeur, Claire; Rhee, David K; Wu, Mei X; Scherrer-Crosbie, Marielle; Buys, Emmanuel S; Zapol, Warren M; Bloch, Kenneth D; Bloch, Donald B

    2016-04-15

    Bone morphogenetic protein (BMP) signaling contributes to the development of cardiac hypertrophy. However, the identity of the BMP type I receptor involved in cardiac hypertrophy and the underlying molecular mechanisms are poorly understood. By using quantitative PCR and immunoblotting, we demonstrated that BMP signaling increased during phenylephrine-induced hypertrophy in cultured neonatal rat cardiomyocytes (NRCs), as evidenced by increased phosphorylation of Smads 1 and 5 and induction of Id1 gene expression. Inhibition of BMP signaling with LDN193189 or noggin, and silencing of Smad 1 or 4 using small interfering RNA diminished the ability of phenylephrine to induce hypertrophy in NRCs. Conversely, activation of BMP signaling with BMP2 or BMP4 induced hypertrophy in NRCs. Luciferase reporter assay further showed that BMP2 or BMP4 treatment of NRCs repressed atrogin-1 gene expression concomitant with an increase in calcineurin protein levels and enhanced activity of nuclear factor of activated T cells, providing a mechanism by which BMP signaling contributes to cardiac hypertrophy. In a model of cardiac hypertrophy, C57BL/6 mice treated with angiotensin II (A2) had increased BMP signaling in the left ventricle. Treatment with LDN193189 attenuated A2-induced cardiac hypertrophy and collagen deposition in left ventricles. Cardiomyocyte-specific deletion of BMP type I receptor ALK2 (activin-like kinase 2), but not ALK1 or ALK3, inhibited BMP signaling and mitigated A2-induced cardiac hypertrophy and left ventricular fibrosis in mice. The results suggest that BMP signaling upregulates the calcineurin/nuclear factor of activated T cell pathway via BMP type I receptor ALK2, contributing to cardiac hypertrophy and fibrosis.

  6. Transgenic expression of an altered angiotensin type I AT1 receptor resulting in marked modulation of vascular type I collagen.

    Science.gov (United States)

    Yu, Jun; Taylor, Linda; Rich, Celeste; Toselli, Paul; Stone, Philip; Green, Daniel; Warburton, Rod; Hill, Nicholas; Goldstein, Ronald; Polgar, Peter

    2012-05-01

    The angiotensin II (AngII) type I receptor (AT1) was modified by replacing its third intracellular loop and C-terminal tail with the corresponding regions from the bradykinin B2 receptor. Transgenic mice were produced that overexpress this mutated receptor (AB3T). Considerably less collagen content in the intact aorta and in primary aortic smooth muscle cells (aSMCs) cultures was observed in the transgenic mice. On the other hand, elastin content remained unchanged as measured by Western blot, and insoluble amino acid quantitation. The contraction of isolated aortas also remained unaltered. The aSMCs derived from the transgenic mice showed a reduction in AngII responsive type I collagen production. In aSMCs from transgenic mice, the cascade of Akt to the mammalian target rapamycin (mTOR) to p70 S6 kinase (p70S6K) was not AngII activated, while in the aSMCs from wild-type (WT) mice the cascade was AngII activated. Angiotensin activation of Smad2 and Stat3 was also reduced in the AB3T aSMCs. However, no change in the effect of transforming growth factor β (TGFβ) on type I collagen production was observed. Also, the activation of ERK and JNK and G-protein linked signaling remained unaltered in response to AngII. Akt and PI3K activation inhibitors blocked AngII-stimulated type I collagen expression in WT aSMCs, whereas ERK inhibitor had no such effect. Our results point to an Akt/mTOR/p70S6K regulation of collagen production by AngII with participation of Smad2 and Stat3 cascades in this process.

  7. Angiotensin II type 1 receptor blockers as a first choice in patients with acute myocardial infarction

    Science.gov (United States)

    Lee, Jang Hoon; Bae, Myung Hwan; Yang, Dong Heon; Park, Hun Sik; Cho, Yongkeun; Lee, Won Kee; Jeong, Myung Ho; Kim, Young Jo; Cho, Myeong Chan; Kim, Chong Jin; Chae, Shung Chull

    2016-01-01

    Background/Aims: Angiotensin II type 1 receptor blockers (ARBs) have not been adequately evaluated in patients without left ventricular (LV) dysfunction or heart failure after acute myocardial infarction (AMI). Methods: Between November 2005 and January 2008, 6,781 patients who were not receiving angiotensin-converting enzyme inhibitors (ACEIs) or ARBs were selected from the Korean AMI Registry. The primary endpoints were 12-month major adverse cardiac events (MACEs) including death and recurrent AMI. Results: Seventy percent of the patients were Killip class 1 and had a LV ejection fraction ≥ 40%. The prescription rate of ARBs was 12.2%. For each patient, a propensity score, indicating the likelihood of using ARBs during hospitalization or at discharge, was calculated using a non-parsimonious multivariable logistic regression model, and was used to match the patients 1:4, yielding 715 ARB users versus 2,860 ACEI users. The effect of ARBs on in-hospital mortality and 12-month MACE occurrence was assessed using matched logistic and Cox regression models. Compared with ACEIs, ARBs significantly reduced in-hospital mortality(1.3% vs. 3.3%; hazard ratio [HR], 0.379; 95% confidence interval [CI], 0.190 to0.756; p = 0.006) and 12-month MACE occurrence (4.6% vs. 6.9%; HR, 0.661; 95% CI, 0.457 to 0.956; p = 0.028). However, the benefit of ARBs on 12-month mortality compared with ACEIs was marginal (4.3% vs. 6.2%; HR, 0.684; 95% CI, 0.467 to 1.002; p = 0.051). Conclusions: Our results suggest that ARBs are not inferior to, and may actually be better than ACEIs in Korean patients with AMI. PMID:26701233

  8. Perioperative angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers for preventing mortality and morbidity in adults.

    Science.gov (United States)

    Zou, Zui; Yuan, Hong B; Yang, Bo; Xu, Fengying; Chen, Xiao Y; Liu, Guan J; Shi, Xue Y

    2016-01-27

    Perioperative hypertension requires careful management. Angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) have shown efficacy in treating hypertension associated with surgery. However, there is lack of consensus about whether they can prevent mortality and morbidity. To systematically assess the benefits and harms of administration of ACEIs or ARBs perioperatively for the prevention of mortality and morbidity in adults (aged 18 years and above) undergoing any type of surgery under general anaesthesia. We searched the current issue of the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 12), Ovid MEDLINE (1966 to 8 December 2014), EMBASE (1980 to 8 December 2014), and references of the retrieved randomized trials, meta-analyses, and systematic reviews. We included randomized controlled trials (RCTs) comparing perioperative administration of ACEIs or ARBs with placebo in adults (aged 18 years and above) undergoing any type of surgery under general anaesthesia. We excluded studies in which participants underwent procedures that required local anaesthesia only, or participants who had already been on ACEIs or ARBs. Two review authors independently performed study selection, assessed the risk of bias, and extracted data. We used standard methodological procedures expected by Cochrane. We included seven RCTs with a total of 571 participants in the review. Two of the seven trials involved 36 participants undergoing non-cardiac vascular surgery (infrarenal aortic surgery), and five involved 535 participants undergoing cardiac surgery, including valvular surgery, coronary artery bypass surgery, and cardiopulmonary bypass surgery. The intervention was started from 11 days to 25 minutes before surgery in six trials and during surgery in one trial. We considered all seven RCTs to carry a high risk of bias. The effects of ACEIs or ARBs on perioperative mortality and acute myocardial infarction were uncertain

  9. Structure of the human angiotensin II type 1 (AT1) receptor bound to angiotensin II from multiple chemoselective photoprobe contacts reveals a unique peptide binding mode.

    Science.gov (United States)

    Fillion, Dany; Cabana, Jérôme; Guillemette, Gaétan; Leduc, Richard; Lavigne, Pierre; Escher, Emanuel

    2013-03-22

    Breakthroughs in G protein-coupled receptor structure determination based on crystallography have been mainly obtained from receptors occupied in their transmembrane domain core by low molecular weight ligands, and we have only recently begun to elucidate how the extracellular surface of G protein-coupled receptors (GPCRs) allows for the binding of larger peptide molecules. In the present study, we used a unique chemoselective photoaffinity labeling strategy, the methionine proximity assay, to directly identify at physiological conditions a total of 38 discrete ligand/receptor contact residues that form the extracellular peptide-binding site of an activated GPCR, the angiotensin II type 1 receptor. This experimental data set was used in homology modeling to guide the positioning of the angiotensin II (AngII) peptide within several GPCR crystal structure templates. We found that the CXC chemokine receptor type 4 accommodated the results better than the other templates evaluated; ligand/receptor contact residues were spatially grouped into defined interaction clusters with AngII. In the resulting receptor structure, a β-hairpin fold in extracellular loop 2 in conjunction with two extracellular disulfide bridges appeared to open and shape the entrance of the ligand-binding site. The bound AngII adopted a somewhat vertical binding mode, allowing concomitant contacts across the extracellular surface and deep within the transmembrane domain core of the receptor. We propose that such a dualistic nature of GPCR interaction could be well suited for diffusible linear peptide ligands and a common feature of other peptidergic class A GPCRs.

  10. Structure of the Human Angiotensin II Type 1 (AT1) Receptor Bound to Angiotensin II from Multiple Chemoselective Photoprobe Contacts Reveals a Unique Peptide Binding Mode*

    Science.gov (United States)

    Fillion, Dany; Cabana, Jérôme; Guillemette, Gaétan; Leduc, Richard; Lavigne, Pierre; Escher, Emanuel

    2013-01-01

    Breakthroughs in G protein-coupled receptor structure determination based on crystallography have been mainly obtained from receptors occupied in their transmembrane domain core by low molecular weight ligands, and we have only recently begun to elucidate how the extracellular surface of G protein-coupled receptors (GPCRs) allows for the binding of larger peptide molecules. In the present study, we used a unique chemoselective photoaffinity labeling strategy, the methionine proximity assay, to directly identify at physiological conditions a total of 38 discrete ligand/receptor contact residues that form the extracellular peptide-binding site of an activated GPCR, the angiotensin II type 1 receptor. This experimental data set was used in homology modeling to guide the positioning of the angiotensin II (AngII) peptide within several GPCR crystal structure templates. We found that the CXC chemokine receptor type 4 accommodated the results better than the other templates evaluated; ligand/receptor contact residues were spatially grouped into defined interaction clusters with AngII. In the resulting receptor structure, a β-hairpin fold in extracellular loop 2 in conjunction with two extracellular disulfide bridges appeared to open and shape the entrance of the ligand-binding site. The bound AngII adopted a somewhat vertical binding mode, allowing concomitant contacts across the extracellular surface and deep within the transmembrane domain core of the receptor. We propose that such a dualistic nature of GPCR interaction could be well suited for diffusible linear peptide ligands and a common feature of other peptidergic class A GPCRs. PMID:23386604

  11. Angiotensin II Type 1 receptor (AGTR1) gene polymorphisms are associated with vascular manifestations in patients with systemic sclerosis (SSc).

    Science.gov (United States)

    Rodríguez-Reyna, Tatiana S; Núñez-Alvarez, Carlos; Cruz-Lagunas, Alfredo; Posadas-Sánchez, Rosalinda; Pérez-Hernández, Nonanzit; Jiménez-Alvarez, Luis; Ramírez-Martínez, Gustavo; Granados, Julio; Vargas-Alarcón, Gilberto; Zúñiga, Joaquín

    2016-07-01

    Systemic sclerosis (SSc) shows variable clinical expression in different ethnic groups; vascular abnormalities are a prominent feature of this disease and its clinical expression may be influenced by genetic factors. Herein, we describe 15 polymorphisms of the renin-angiotensin-aldosterone pathway in 170 Mexican admixed SSc patients (defined as patients with Mexican ancestry for at least 3 generations) and 199 healthy controls. We determined the presence of angiotensin II Type 1 receptor (AGTR1), angiotensin converting enzyme (ACE) and Endothelin 1 single nucleotide polymorphisms (SNPs) using 5' exonuclease TaqMan genotyping assays on a 7900HT real-time fast polymerase chain reaction (PCR) system. These polymorphisms had a similar distribution between SSc patients and controls, but we found that the AGTR1 G-680T (rs275652) (p = 0.02; OR 3.5; 95%CI 1.2-10.4) and AGTR1 A-119G (rs275653) (p = 0.008; OR 4.2; 95% CI 1.5-12.1) polymorphisms were associated with severe vascular involvement in our SSc patients. This is the first report of the association of these polymorphisms with vasculopathy in Mexican admixed SSc patients. Our findings suggested that the angiotensin II Type 1 receptor genotype may influence the clinical expression of vasculopathy in these patients. Functional analyses should follow. © The Author(s) 2016.

  12. INHIBITORY EFFECT OF ANGIOTENSINTYPE 1 RECEPTOR-ASSOCIATED PROTEIN ON VASCULAR SMOOTH MUSCLE CELL GROWTH AND NEOINTIMAL FORMATION

    Institute of Scientific and Technical Information of China (English)

    Zhen Li; Zhong-gao Wang; Xiu Chen; Xiao-dong Chen

    2007-01-01

    Objective To investigate the mechanism of a novel angiotensin n type 1 receptor-associated protein (ATRAP) interfering with angiotensintype 1 (AT1) receptor-mediated vascular smooth muscle cell (VSMC) growth and neointimal formation. Methods VSMCs isolated from thoracic aorta of adult Sprague-Dawley ( SD) rats were used in this study. ATRAP Cdna was subcloned into pcDNA3 vector and then transfected into VSMCs. DNA synthesis and extracellular signal-regulated kinase (ERK) and phospho-ERK expressions in VSMCs were assayed by measurement of 3H thymidine incorporation and Western blotting, respectively. Morphological changes were observed in the balloon injured artery with or without transfection of ATRAP Cdna using 12-week-old male SD rats. Results ATRAP overexpression in VSMCs inhibited angiotensin Ⅱ (Ang Ⅱ) -induced 3H thymidine incorporation 48 hours after Ang Ⅱ stimulation (P < 0.05). In VSMC, Ang Ⅱ stimulation increased the phosphorylation of ERK, which reached the peak around 60 minutes. The activation of phospho-ERK was significantly decreased by ATRAP (P < 0.05). Neointimal formation was markedly inhibited by ATRAP overexpression in injuried arteries. Conclusions The AT1 receptor-derived activation of ERK plays an essential role in Ang Ⅱ-induced VSMC growth. The growth inhibitory effects of ATRAP might be due to interfering with AT1 receptor-mediated activation of ERK in VSMC growth and neointimal formation.

  13. Hypercholesterolemia blunts the oxidative stress elicited by hypertension in venules through angiotensin II type-2 receptors

    Science.gov (United States)

    Yildirim, Alper; Senchenkova, Elena; Granger, D. Neil

    2016-01-01

    OBJECTIVE Hypertension and hypercholesterolemia elicit inflammatory and thrombogenic responses in the microvasculature. However, little is known about whether and how risk factor combinations alter microvascular function. We examined how the actions of HTN+HCh on the microvasculature differ from the responses elicited by either risk factor alone. METHODS Intravital microscopy was used to monitor the adhesion and emigration of leukocytes and dihydrorhodamine oxidation in cremaster muscle venules of wild type mice that were infused with angiotensin II for 2 wks (HTN), placed on a high cholesterol diet (HCD), or both. RESULTS Either HTN or HCh alone enhanced the production of reactive oxygen species and promoted the recruitment of leukocytes in venules. However, the combination of HTN and HCh produced changes in ROS production and leukocyte recruitment that were greatly attenuated compared to HTN alone. The inhibitory effects of HCh on the AngII mediated responses were also observed in genetically-induced HCh (ApoE-deficient mice). Treating HCh + HTN mice with an antagonist to AT2r reversed the HCh-dependent protection against oxidative stress and inflammation during HTN. CONCLUSIONS These findings indicate that HCh blunts the oxidative stress and inflammatory cell recruitment elicited by hypertension in venules through a mechanism that involves AT2 receptor activation. PMID:26775070

  14. Regulation of angiotensin II type 1 receptor expression in ovarian cancer: a potential role for BRCA1

    OpenAIRE

    Bi, Fang-Fang; Li, Da; Cao, Chen; Li, Chun-Yan; Yang, Qing

    2013-01-01

    Background Both BRCA1 and angiotensin II type 1 receptor (AGTR1) play a critical role in ovarian cancer progression. However, the crosstalk between BRCA1 and AGTR1 signaling pathways remains largely unknown. Methods BRCA1 promoter methylation was analyzed by bisulfite sequence using primers focused on the core promoter region. Expression levels of BRCA1 and AGTR1 were assessed by immunohistochemistry and real-time PCR. Regression analysis was used to examine the possible relationship between ...

  15. Biased signaling of the angiotensin II type 1 receptor can be mediated through distinct mechanisms.

    Directory of Open Access Journals (Sweden)

    Marie Mi Bonde

    Full Text Available BACKGROUND: Seven transmembrane receptors (7TMRs can adopt different active conformations facilitating a selective activation of either G protein or β-arrestin-dependent signaling pathways. This represents an opportunity for development of novel therapeutics targeting selective biological effects of a given receptor. Several studies on pathway separation have been performed, many of these on the Angiotensin II type 1 receptor (AT1R. It has been shown that certain ligands or mutations facilitate internalization and/or recruitment of β-arrestins without activation of G proteins. However, the underlying molecular mechanisms remain largely unresolved. For instance, it is unclear whether such selective G protein-uncoupling is caused by a lack of ability to interact with G proteins or rather by an increased ability of the receptor to recruit β-arrestins. Since uncoupling of G proteins by increased ability to recruit β-arrestins could lead to different cellular or in vivo outcomes than lack of ability to interact with G proteins, it is essential to distinguish between these two mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: We studied five AT1R mutants previously published to display pathway separation: D74N, DRY/AAY, Y292F, N298A, and Y302F (Ballesteros-Weinstein numbering: 2.50, 3.49-3.51, 7.43, 7.49, and 7.53. We find that D74N, DRY/AAY, and N298A mutants are more prone to β-arrestin recruitment than WT. In contrast, receptor mutants Y292F and Y302F showed impaired ability to recruit β-arrestin in response to Sar1-Ile4-Ile8 (SII Ang II, a ligand solely activating the β-arrestin pathway. CONCLUSIONS/SIGNIFICANCE: Our analysis reveals that the underlying conformations induced by these AT1R mutants most likely represent principally different mechanisms of uncoupling the G protein, which for some mutants may be due to their increased ability to recruit β-arrestin2. Hereby, these findings have important implications for drug discovery and 7TMR

  16. Dietary sodium deprivation evokes activation of brain regional neurons and down-regulation of angiotensin II type 1 receptor and angiotensin-convertion enzyme mRNA expression.

    Science.gov (United States)

    Lu, B; Yang, X J; Chen, K; Yang, D J; Yan, J Q

    2009-12-15

    Previous studies have indicated that the renin-angiotensin-aldosterone system (RAAS) is implicated in the induction of sodium appetite in rats and that different dietary sodium intakes influence the mRNA expression of central and peripheral RAAS components. To determine whether dietary sodium deprivation activates regional brain neurons related to sodium appetite, and changes their gene expression of RAAS components of rats, the present study examined the c-Fos expression after chronic exposure to low sodium diet, and determined the relationship between plasma and brain angiotensin I (ANG I), angiotensin II (ANG II) and aldosterone (ALD) levels and the sodium ingestive behavior variations, as well as the effects of prolonged dietary sodium deprivation on ANG II type 1 (AT1) and ANG II type 2 (AT2) receptors and angiotensin-convertion enzyme (ACE) mRNA levels in the involved brain regions using the method of real-time polymerase chain reaction (PCR). Results showed that the Fos immunoreactivity (Fos-ir) expression in forebrain areas such as subfornical organ (SFO), paraventricular hypothalamic nuclei (PVN), supraoptic nucleus (SON) and organum vasculosum laminae terminalis (OVLT) all increased significantly and that the levels of ANG I, ANG II and ALD also increased in plasma and forebrain in rats fed with low sodium diet. In contrast, AT1, ACE mRNA in PVN, SON and OVLT decreased significantly in dietary sodium depleted rats, while AT2 mRNA expression did not change in the examined areas. These results suggest that many brain areas are activated by increased levels of plasma and/or brain ANG II and ALD, which underlies the elevated preference for hypertonic salt solution after prolonged exposure to low sodium diet, and that the regional AT1 and ACE mRNA are down-regulated after dietary sodium deprivation, which may be mediated by increased ANG II in plasma and/or brain tissue.

  17. Variations of the angiotensin II type 1 receptor gene are associated with extreme human longevity.

    Science.gov (United States)

    Benigni, Ariela; Orisio, Silvia; Noris, Marina; Iatropoulos, Paraskevas; Castaldi, Davide; Kamide, Kei; Rakugi, Hiromi; Arai, Yasumichi; Todeschini, Marta; Ogliari, Giulia; Imai, Enyu; Gondo, Yasuyuki; Hirose, Nobuyoshi; Mari, Daniela; Remuzzi, Giuseppe

    2013-06-01

    Longevity phenotype in humans results from the influence of environmental and genetic factors. Few gene polymorphisms have been identified so far with a modest effect on lifespan leaving room for the search of other players in the longevity game. It has been recently demonstrated that targeted disruption of the mouse homolog of the human angiotensin II type 1 receptor (AT1R) gene (AGTR1) translates into marked prolongation of animal lifespan (Benigni et al., J Clin Invest 119(3):524-530, 2009). Based on the above study in mice, here we sought to search for AGTR1 variations associated to reduced AT1 receptor protein levels and to prolonged lifespan in humans. AGTR1 was sequenced in 173 Italian centenarians and 376 younger controls. A novel non-synonymous mutation was detected in a centenarian. Two polymorphisms in AGTR1 promoter, rs422858 and rs275653, in complete linkage disequilibrium, were significantly associated with the ability to attain extreme old age. We then replicated the study of rs275653 in a large independent cohort of Japanese origin (598 centenarians and semi-supercentenarians, 422 younger controls) and indeed confirmed its association with exceptional old age. In combined analyses, rs275653 was associated to extreme longevity either at recessive model (P = 0.007, odds ratio (OR) 3.57) or at genotype level (P = 0.015). Significance was maintained after correcting for confounding factors. Fluorescence activated cell sorting analysis revealed that subjects homozygous for the minor allele of rs275653 had less AT1R-positive peripheral blood polymorphonuclear cells. Moreover, rs275653 was associated to lower blood pressure in centenarians. These findings highlight the role of AGTR1 as a possible candidate among longevity-enabling genes.

  18. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in patients with abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Kristensen, Karl Emil; Torp-Pedersen, Christian; Gislason, Gunnar Hilmar;

    2015-01-01

    OBJECTIVE: The renin-angiotensin system is thought to play a pivotal role in the pathogenesis of abdominal aortic aneurysms (AAAs). However, effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) on human AAAs remain unclear. We therefore ex...

  19. Angiotensin II receptor type 1 blockers suppress the cell proliferation effects of angiotensin II in breast cancer cells by inhibiting AT1R signaling.

    Science.gov (United States)

    Du, Ning; Feng, Jiang; Hu, Li-Juan; Sun, Xin; Sun, Hai-Bing; Zhao, Yang; Yang, Yi-Ping; Ren, Hong

    2012-06-01

    Chronic stress and a high-fat diet are well-documented risk factors associated with the renin-angiotensin system in the development of breast cancer. The angiotensin II type 1 receptor (AT1R) is a novel component of the renin-angiotensin system. Several recent studies have focused on the function of AT1R in cell proliferation during cancer development. Thus, we hypothesized that angiotensin II (Ang Ⅱ) can promote proliferation of breast cancer via activated AT1R; the activation of AT1R may play an important role in promoting breast cancer growth, and AT1R blocker (ARB) may suppress the promotional effect on proliferation by antagonizing AT1R. The expression level of AT1R was found to be significantly upregulated in breast cancer cells by immunohistochemistry, but no correlation between AT1R expression and ER/PR/Her-2 expression was observed. The AT1R(+)-MCF-7 cell line exhibited high expression of AT1R protein, and we generated the AT1R(-)-MCF-7 cell line using RNA interference. ARBs, and in particular irbesartan, effectively inhibited the effects of Ang II on cell proliferation, cell cycle development and downstream AT1R signaling events, including the activation of the Ras-Raf-MAPK pathway and the transcription factors NF-κB and CREB. Irbesartan also significantly altered p53, PCNA and cyclin D1 expression, which was also influenced by activated AT1R in AT1R(+)-MCF-7 cells. These results suggest that ARBs may be useful as a novel preventive and therapeutic strategy for treating breast cancer.

  20. Overexpression of the human angiotensin II type 1 receptor in the rat heart augments load induced cardiac hypertrophy

    NARCIS (Netherlands)

    Hoffmann, S; van Geel, PP; Willenbrock, R; Pagel, [No Value; Pinto, YM; Buikema, H; van Gilst, WH; Lindschau, C; Paul, M; Inagami, T; Ganten, D; Urata, H

    2001-01-01

    Angiotensin II is known to stimulate cardiac hypertrophy and contractility. Most angiotensin II effects are mediated via membrane bound AT(1) receptors. However, the role of myocardial AT(1) receptors in cardiac hypertrophy and contractility is still rarely defined. To address the hypothesis that in

  1. Overexpression of the human angiotensin II type 1 receptor in the rat heart augments load induced cardiac hypertrophy

    NARCIS (Netherlands)

    Hoffmann, S; van Geel, PP; Willenbrock, R; Pagel, [No Value; Pinto, YM; Buikema, H; van Gilst, WH; Lindschau, C; Paul, M; Inagami, T; Ganten, D; Urata, H

    2001-01-01

    Angiotensin II is known to stimulate cardiac hypertrophy and contractility. Most angiotensin II effects are mediated via membrane bound AT(1) receptors. However, the role of myocardial AT(1) receptors in cardiac hypertrophy and contractility is still rarely defined. To address the hypothesis that

  2. Regulation of angiotensin-(1-7) and angiotensintype 1 receptor by telmisartan and losartan in adriamycin-induced rat heart failure

    Institute of Scientific and Technical Information of China (English)

    Wen-na ZONG; Xin-zheng LU; Xiao-hui YANG; Xiu-mei CHEN; Hong-juan HUANG; Hong-jian ZHENG; Xiao-yi QIN; Yong-hong YONG; Ke-jiang CAO; Jun HUANG

    2011-01-01

    Aim:To investigate the possible effects of telmisartan and losartan on cardiac function in adriamycin (ADR)-induced heart failure in rats,and to explore the changes in plasma level of angiotensin-(1-7)[Ang-(1-7)] and myocardial expression of angiotensintype 1/2 receptors (AT1R / AT2R) and Mas receptor caused by the two drugs.Methods:Male Sprague-Dawley rats were randomly divided into 4 groups:the control group,ADR-treated heart failure group (ADR-HF),telmisartan plus ADR-treated group (Tel+ADR) and losartan plus ADR-treated group (Los+ADR).ADR was administrated (2.5 mg/kg,ip,6 times in 2 weeks).The rats in the Tel+ADR and Los+ADR groups were treated orally with telmisartan (10 mg/kg daily po) and losartan (30 mg/kg daily),respectively,for 6 weeks.The plasma level of Ang-(1-7) was determined using ELISA.The mRNA and protein expression of myocardial Mas receptor,AT1R and AT2R were measured using RT-PCR and Western blotting,respectively.Results:ADR significantly reduced the plasma level of Ang-(1-7) and the expression of myocardial Mas receptor and myocardial AT2R,while significantly increased the expression of myocardial AT1R.Treatment with telmisartan and losartan effectively increased the plasma level of Ang-(1-7) and suppressed myocardial AT1R expression,but did not influence the expression of Mas receptor and AT2R.Conclusion:The protective effects of telmisartan and losartan in ADR-induced heart failure may be partially due to regulation of circulating Ang-(1-7) and myocardial AT1R expression.

  3. Impact of Angiotensin I-converting Enzyme Inhibitors and Angiotensin II Type-1 Receptor Blockers on Survival of Patients with NSCLC

    Science.gov (United States)

    Miao, Lili; Chen, Wei; Zhou, Ling; Wan, Huanying; Gao, Beili; Feng, Yun

    2016-01-01

    It has been shown that angiotensin I-converting enzyme inhibitors (ACEIs) and angiotensin II type-1 receptor blockers (ARBs) can decrease tumor growth and tumor-associated angiogenesis and inhibit metastasis. Epidermal growth factor receptor (EGFR) mutations are found in approximately 30% of patients with advanced non-small cell lung cancer (NSCLC) in East Asia and in 10–15% of such patients in Western countries. We retrospectively identified 228 patients with histologically confirmed advanced NSCLC and 73 patients with early stage disease; 103 of these patients took antihypertensive drugs, and 112 received treatment with EGFR tyrosine kinase inhibitors (TKIs). There was a significant difference in progression-free survival after first-line therapy (PFS1) between the ACEI/ARB group and the non-ACEI/ARB group. For the patients treated with TKIs, there was a significant difference in PFS but not in overall survival (OS) between the ACEI/ARB group and the non-ACEI/ARB group. For the patients with advanced NSCLC, there was a significant difference in PFS1 between the ACEI/ARB group and the non-ACEI/ARB group. ACEI/ARB in combination with standard chemotherapy or TKIs had a positive effect on PFS1 or OS, regardless of whether the lung cancer was in the early or advanced stage. PMID:26883083

  4. Reduced growth, abnormal kidney structure, and type 2 (AT2) angiotensin receptor-mediated blood pressure regulation in mice lacking both AT1A and AT1B receptors for angiotensin II

    OpenAIRE

    Oliverio, Michael I.; Kim, Hyung-Suk; Ito, Masaki; Le, Thu; Audoly, Laurent; Best, Christopher F.; Hiller, Sylvia; Kluckman, Kimberly; Maeda, Nobuyo; Smithies, Oliver; Coffman, Thomas M.

    1998-01-01

    The classically recognized functions of the renin–angiotensin system are mediated by type 1 (AT1) angiotensin receptors. Whereas man possesses a single AT1 receptor, there are two AT1 receptor isoforms in rodents (AT1A and AT1B) that are products of separate genes (Agtr1a and Agtr1b). We have generated mice lacking AT1B (Agtr1b −/−) and both AT1A and AT1B receptors (Agtr1a −/−Agtr1b −/−). Agtr1b −/− mice are healthy, without an abnormal phenotype. In contrast, Agtr1a −/−Agtr1b −/− mice have d...

  5. Polymorphisms in angiotensin II type 1 receptor and angiotensin I-converting enzyme genes and breast cancer risk among Chinese women in Singapore.

    Science.gov (United States)

    Koh, Woon-Puay; Yuan, Jian-Min; Van Den Berg, David; Lee, Hin-Peng; Yu, Mimi C

    2005-02-01

    Angiotensin II is converted from its precursor by angiotensin I-converting enzyme (ACE) and has been shown to mediate growth in breast cancer cell lines via ligand-induced activity through the angiotensin II type 1 receptor (AGTR1). Earlier we showed that women with the low activity genotype of the ACE gene have a statistically significantly ( approximately 50%) reduced breast cancer risk compared with those possessing the high activity ACE genotype. To further test the hypothesis that angiotensin II participates in breast carcinogenesis through AGTR1, we examined genetic polymorphisms in the 5'-region of the AGTR1 gene (A-168G, C-535T and T-825A) in relation to risk of breast cancer in 258 breast cancer cases and 670 female controls within the Singapore Chinese Health Study. Relative to the homozygotes, individual genotypes with one or two copies of the respective allelic variants (putative low risk genotypes) were each associated with an approximately 30% reduction in risk of breast cancer. Risk of breast cancer decreased with increasing number of low risk AGTR1 genotypes after adjustment for potential confounders. Relative to those carrying no low risk genotypes (homozygous for A, C and T alleles for the three polymorphisms, respectively), the odds ratios (95% confidence intervals) were 0.84 (0.51-1.37) for women possessing one low risk genotype and 0.68 (0.46-1.01) for women possessing two or three low risk genotypes (P for trend = 0.05). When both AGTR1 and ACE gene polymorphisms were examined simultaneously, women possessing at least one AGTR1 low risk genotype in combination with the ACE low activity genotype had an odds ratio of 0.35 (95% confidence interval, 0.20-0.62) compared with those possessing the ACE high activity genotype and no AGTR1 low risk genotype. Our findings suggest that pharmacological inhibition of the angiotensin II effect by blockade of ACE and/or AGTR1 could be potential targets for the prevention and treatment of breast cancer.

  6. Rapid detection of the hypertension-associated A1166C polymorphism of the angiotensin II type 1 receptor (AGTR1).

    Science.gov (United States)

    Stankovic, Aleksandra; Alavantic, Dragan

    2002-01-01

    Screening for polymorphisms in the human type 1 angiotensin II receptor locus (AGTR1) has led to the identification of an A1166C transversion in the 3'-untranslated region. This molecular variant, C(1166), has been linked to essential hypertension. We describe here a rapid method for the detection of this point mutation by a simple modification of PCR amplification with allele-specific oligonucleotides (ASO), so as to avoid a hybridization procedure involving either radioactive- or non-radioactive-labeled probes, labeled primers, or restriction typing. The procedure described is convenient for routine clinical laboratory use with manual sample processing and offers the potential for further automation, as well.

  7. OS 32-03 ANGIOTENSIN II TYPE 2 RECEPTOR AGONIST EXERTS SUSTAINED NEUROPROTECTIVE EFFECTS IN AGED RATS

    DEFF Research Database (Denmark)

    Sumners, Colin; Isenberg, Jacob; Harmel, Allison;

    2016-01-01

    OBJECTIVE: The renin angiotensin system is a promising target for stroke neuroprotection and therapy through activation of angiotensin type II receptors (AT2R). The selective non-peptide AT2R agonist, Compound 21 (C21), has been shown to exhibit neuroprotection and improve stroke outcomes...... min), 24 h, and 48 h after stroke. Infarct size was assessed by magnetic resonance imaging at 21 days post MCAO. Animals received blinded neurological exams at 4 h, 24 h, 72 h, 7d, 14d, and 21d post-MCAO. RESULTS: Systemic treatment with C21 after stroke significantly improved neurological function...

  8. Mechanical stress triggers cardiomyocyte autophagy through angiotensin II type 1 receptor-mediated p38MAP kinase independently of angiotensin II.

    Directory of Open Access Journals (Sweden)

    Li Lin

    Full Text Available Angiotensin II (Ang II type 1 (AT1 receptor is known to mediate a variety of physiological actions of Ang II including autophagy. However, the role of AT1 receptor in cardiomyocyte autophagy triggered by mechanical stress still remains elusive. The aim of this study was therefore to examine whether and how AT1 receptor participates in cardiomyocyte autophagy induced by mechanical stresses. A 48-hour mechanical stretch and a 4-week transverse aorta constriction (TAC were imposed to cultured cardiomyocytes of neonatal rats and adult male C57B/L6 mice, respectively, to induce cardiomyocyte hypertrophy prior to the assessment of cardiomyocyte autophagy using LC3b-II. Losartan, an AT1 receptor blocker, but not PD123319, the AT2 inhibitor, was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Moreover, inhibition of p38MAP kinase attenuated not only mechanical stretch-induced cardiomyocyte hypertrophy but also autophagy. To the contrary, inhibition of ERK and JNK suppressed cardiac hypertrophy but not autophagy. Intriguingly, mechanical stretch-induced autophagy was significantly inhibited by Losartan in the absence of Ang II. Taken together, our results indicate that mechanical stress triggers cardiomyocyte autophagy through AT1 receptor-mediated activation of p38MAP kinase independently of Ang II.

  9. Direct angiotensin II type 2 receptor stimulation ameliorates insulin resistance in type 2 diabetes mice with PPARγ activation.

    Directory of Open Access Journals (Sweden)

    Kousei Ohshima

    Full Text Available OBJECTIVES: The role of angiotensin II type 2 (AT(2 receptor stimulation in the pathogenesis of insulin resistance is still unclear. Therefore we examined the possibility that direct AT(2 receptor stimulation by compound 21 (C21 might contribute to possible insulin-sensitizing/anti-diabetic effects in type 2 diabetes (T2DM with PPARγ activation, mainly focusing on adipose tissue. METHODS: T2DM mice, KK-Ay, were subjected to intraperitoneal injection of C21 and/or a PPARγ antagonist, GW9662 in drinking water for 2 weeks. Insulin resistance was evaluated by oral glucose tolerance test, insulin tolerance test, and uptake of 2-[(3H] deoxy-D-glucose in white adipose tissue. Morphological changes of adipose tissues as well as adipocyte differentiation and inflammatory response were examined. RESULTS: Treatment with C21 ameliorated insulin resistance in KK-Ay mice without influencing blood pressure, at least partially through effects on the PPARγ pathway. C21 treatment increased serum adiponectin concentration and decreased TNF-α concentration; however, these effects were attenuated by PPARγ blockade by co-treatment with GW9662. Moreover, we observed that administration of C21 enhanced adipocyte differentiation and PPARγ DNA-binding activity, with a decrease in inflammation in white adipose tissue, whereas these effects of C21 were attenuated by co-treatment with GW9662. We also observed that administration of C21 restored β cell damage in diabetic pancreatic tissue. CONCLUSION: The present study demonstrated that direct AT(2 receptor stimulation by C21 accompanied with PPARγ activation ameliorated insulin resistance in T2DM mice, at least partially due to improvement of adipocyte dysfunction and protection of pancreatic β cells.

  10. Gene polymorphisms of angiotensin-converting enzyme and angiotensin II type 1 receptor among chronic kidney disease patients in a Chinese population.

    Science.gov (United States)

    Su, Sui-Lung; Lu, Kuo-Cheng; Lin, Yuh-Feng; Hsu, Yu-Juei; Lee, Pong-Ying; Yang, Hsin-Yi; Kao, Sen-Yeong

    2012-03-01

    Chronic kidney disease (CKD) is highly prevalent in Taiwan and an increasing number of patients are affected, with a high risk of progression to end-stage renal disease and huge medical expenses. It has been predicted that the presence of hypertension increases with decreasing renal function due to a decrease in sodium excretion and activation of the renin-angiotensin system (RAS). The aim of this study was to investigate the influence of genetic variants of the RAS gene on CKD. We performed a case control association study and genotyped 135 CKD patients and 270 healthy controls among Han Chinese in Taiwan. All subjects were genotyped for angiotensinogen (AGT-M235T, T174M, A-20C), angiotensin-I converting enzyme (ACE-A2350G) and angiotensin II type 1 receptor (AGTR1-A1166C, C573T, C-521T) polymorphisms of RAS genes by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Significant associations were observed in ACE-A2350G and AGTR1-C573T polymorphism between CKD patients and controls. In regard to ACE-A2350G, compared with the AA genotype the GG genotype protected against CKD (adjusted odds ratio [OR] = 0.34; p = 0.01). In regard to AGTR1-C573T, the CT genotype was a risk for CKD compared with the CC genotype (adjusted OR = 1.82; p = 0.03). We conclude that ACE-A2350G and AGTR1-C573T polymorphisms are likely candidate determinants of CKD.

  11. Age determines the magnitudes of angiotensin II-induced contractions, mRNA, and protein expression of angiotensin type 1 receptors in rat carotid arteries.

    Science.gov (United States)

    Vamos, Zoltan; Cseplo, Peter; Ivic, Ivan; Matics, Robert; Hamar, Janos; Koller, Akos

    2014-05-01

    In this study, we hypothesized that aging alters angiotensin II (Ang II)-induced vasomotor responses and expression of vascular mRNA and protein angiotensin type 1 receptor (AT1R). Thus, carotid arteries were isolated from the following age groups of rats: 8 days, 2-9 months, 12-20 months, and 20-30 months, and their vasomotor responses were measured in a myograph after repeated administrations of Ang II. Vascular relative AT1R mRNA level was determined by quantitative reverse-transcriptase polymerase chain reaction and the AT1R protein density was measured by Western blot. Contractions to the first administration of Ang II increased from 8 days to 6 months and then they decreased to 30 months. In general, second administration of Ang II elicited reduced contractions, but they also increased from 8 days until 2 months and then they decreased to 30 months. Similarly the AT1R mRNA level increased from 8 days to 12 months and then decreased to 30 months. Similarly the AT1R protein density increased from 8 days until 16 months and then they decreased to 30 months. The pattern of these changes correlated with functional vasomotor data. We conclude that aging (newborn to senescence) has substantial effects on Ang II-induced vasomotor responses and AT1R signaling suggesting the importance of genetic programs.

  12. Clinical and Pharmacotherapeutic Relevance of the Double-Chain Domain of the Angiotensin II Type 1 Receptor Blocker Olmesartan

    OpenAIRE

    Kiya, Yoshihiro; Miura, Shin-ichiro; Fujino, Masahiro; Imaizumi, Satoshi; Karnik, Sadashiva S.; Saku, Keijiro

    2010-01-01

    We previously reported that the angiotensin II type 1 (AT1) receptor blocker (ARB) olmesartan has two important interactions to evoke inverse agonism (IA). We refer to these interactions as the “double-chain domain (DCD).” Since the clinical pharmacotherapeutic relevance of olmesartan is still unclear, we examined these effects in rats and humans. We analyzed the effects at an advanced stage of renal insufficiency in Dahl salt-sensitive hypertensive rats (Study 1). Rats were fed a high-salt d...

  13. Angiotensin II type 1 receptor blocker losartan prevents and rescues cerebrovascular, neuropathological and cognitive deficits in an Alzheimer's disease model.

    Science.gov (United States)

    Ongali, Brice; Nicolakakis, Nektaria; Tong, Xin-Kang; Aboulkassim, Tahar; Papadopoulos, Panayiota; Rosa-Neto, Pedro; Lecrux, Clotilde; Imboden, Hans; Hamel, Edith

    2014-08-01

    Angiotensin II (AngII) receptor blockers that bind selectively AngII type 1 (AT1) receptors may protect from Alzheimer's disease (AD). We studied the ability of the AT1 receptor antagonist losartan to cure or prevent AD hallmarks in aged (~18months at endpoint, 3months treatment) or adult (~12months at endpoint, 10months treatment) human amyloid precursor protein (APP) transgenic mice. We tested learning and memory with the Morris water maze, and evaluated neurometabolic and neurovascular coupling using [(18)F]fluoro-2-deoxy-D-glucose-PET and laser Doppler flowmetry responses to whisker stimulation. Cerebrovascular reactivity was assessed with on-line videomicroscopy. We measured protein levels of oxidative stress enzymes (superoxide dismutases SOD1, SOD2 and NADPH oxidase subunit p67phox), and quantified soluble and deposited amyloid-β (Aβ) peptide, glial fibrillary acidic protein (GFAP), AngII receptors AT1 and AT2, angiotensin IV receptor AT4, and cortical cholinergic innervation. In aged APP mice, losartan did not improve learning but it consolidated memory acquisition and recall, and rescued neurovascular and neurometabolic coupling and cerebrovascular dilatory capacity. Losartan normalized cerebrovascular p67phox and SOD2 protein levels and up-regulated those of SOD1. Losartan attenuated astrogliosis, normalized AT1 and AT4 receptor levels, but failed to rescue the cholinergic deficit and the Aβ pathology. Given preventively, losartan protected cognitive function, cerebrovascular reactivity, and AT4 receptor levels. Like in aged APP mice, these benefits occurred without a decrease in soluble Aβ species or plaque load. We conclude that losartan exerts potent preventive and restorative effects on AD hallmarks, possibly by mitigating AT1-initiated oxidative stress and normalizing memory-related AT4 receptors.

  14. 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.

  15. Changes of chymase, angiotensin converting enzyme and angiotensintype 1 receptor expressions in the hamster heart during the development of heart failure

    Institute of Scientific and Technical Information of China (English)

    CHEN Peng-min; LENG Xi-gang; FAN Li-li; MA Jun; WANG Ya-fang; CHEN Lan-ying

    2005-01-01

    Background Little is known about the role of dual angiotensin Ⅱ forming pathways during heart failure. In the present study, the changes of chymase and angiotensin converting enzyme (ACE) expressions in the failing hearts of hamsters were analysed.Methods Heart failure was induced by ligation of left anterior descending branch of the coronary artery. Chymase, ACE and angiotensintype 1 receptor (AT1R) mRNA levels were analysed by reverse transcription polymerase chain reaction (RT-PCR). The activities of chymase and ACE were determined by radioimmunoassay (RIA). Myocardial collagen fibre analysis was performed under optical microscope.Results Left ventricular systolic pressure (LVSP) and maximum left ventricular developed pressure increase rate (dp/dtmax, mmHg/s) gradually moved lower at 2, 3, 4 and 8 weeks after operation. On the other hand, left ventricular end-diastolic pressure (LVEDP) increased gradually after operation. Compared with the control group (3.55±0.06, 4.79±0.70), the heart weight/body weight ratio in operation group had increased significantly at 4 weeks and 8 weeks (4.28±0.43, 6.17±0.73) (P<0.01). Collagen staining showed that the quantity of myocardial collagen fibre increased significantly in the operation group. RT-PCR showed that the chymase mRNA level in the operation group was consistently greater than that in the control group. AT1R mRNA level was also increased significantly at 3 weeks and 4 weeks, both being 1.3 times that of the control group (P<0.01), whereas ACE mRNA level was not changed. Higher activity of chymase was detected in operation group, being 4, 8, 13 and 19 times that of the control group at 2, 3, 4 and 8 weeks (P<0.01), respectively. ACE activity was also significantly higher at the same time, being 7, 10, 10 and 3.5 times that of the control (P<0.01). Angiotensin Ⅱ (Ang Ⅱ) level in operation group increased significantly, being 2.5, 2.7, 3.5 and 2 times that of the control group at 2, 3, 4 and 8 weeks

  16. Impact of cell type and epitope tagging on heterologous expression of G protein-coupled receptor: a systematic study on angiotensin type II receptor.

    Directory of Open Access Journals (Sweden)

    Lili Jiang

    Full Text Available Despite heterologous expression of epitope-tagged GPCR is widely adopted for functional characterization, there is lacking of systematic analysis of the impact of expression host and epitope tag on GPCR expression. Angiotensin type II (AT2 receptor displays agonist-dependent and -independent activities, coupling to a spectrum of signaling molecules. However, consensus has not been reached on the subcellular distributions, signaling cascades and receptor-mediated actions. To examine the contributions of host cell and epitope tag on receptor expression and activity, epitope-tagged AT2 receptor variants were transiently or stably expressed in HEK293, CHO-K1 and PC12 cells. The epitope-tagged AT2 receptor variants were detected both on the cell membrane and in the perinuclear region. In transiently transfected HEK293 cells, Myc-AT2 existed predominantly as monomer. Additionally, a ladder of ubiquitinated AT2 receptor proteins was detected. By contrast, stably expressed epitope-tagged AT2 receptor variants existed as both monomer and high molecular weight complexes, and the latter was enriched in cell surface. Glycosylation promoted cell surface expression of Myc-AT2 but had no effect on AT2-GFP in HEK293 cells. In cells that stably expressed Myc-AT2, serum starvation induced apoptosis in CHO-K1 cells but not in HEK293 or PC12 cells. Instead, HEK293 and PC12 cells stably expressing Myc-AT2 exhibited partial cell cycle arrest with cells accumulating at G1 and S phases, respectively. Taken together, these results suggest that expression levels, subcellular distributions and ligand-independent constitutive activities of AT2 receptor were cell type-dependent while posttranslational processing of nascent AT2 receptor protein was modulated by epitope tag and mode of expression.

  17. Differential Contribution of Transmembrane Domains IV, V, VI, and VII to Human Angiotensin II Type 1 Receptor Homomer Formation.

    Science.gov (United States)

    Young, Brent M; Nguyen, Elaine; Chedrawe, Matthew A J; Rainey, Jan K; Dupré, Denis J

    2017-02-24

    G protein-coupled receptors (GPCRs) play an important role in drug therapy and represent one of the largest families of drug targets. The angiotensin II type 1 receptor (AT1R) is notable as it has a central role in the treatment of cardiovascular disease. Blockade of AT1R signaling has been shown to alleviate hypertension and improve outcomes in patients with heart failure. Despite this, it has become apparent that our initial understanding of AT1R signaling is oversimplified. There is considerable evidence to suggest that AT1R signaling is highly modified in the presence of receptor-receptor interactions, but there is very little structural data available to explain this phenomenon even with the recent elucidation of the AT1R crystal structure. The current study investigates the involvement of transmembrane domains in AT1R homomer assembly with the goal of identifying hydrophobic interfaces that contribute to receptor-receptor affinity. A recently published crystal structure of the AT1R was used to guide site-directed mutagenesis of outward-facing hydrophobic residues within the transmembrane region of the AT1R. Bioluminescence resonance energy transfer was employed to analyze how receptor mutation affects the assembly of AT1R homomers with a specific focus on hydrophobic residues. Mutations within transmembrane domains IV, V, VI, and VII had no effect on angiotensin-mediated β-arrestin1 recruitment; however, they exhibited differential effects on the assembly of AT1R into oligomeric complexes. Our results demonstrate the importance of hydrophobic amino acids at the AT1R transmembrane interface and provide the first glimpse of the requirements for AT1R complex assembly.

  18. Post-stroke angiotensin II type 2 receptor activation provides long-term neuroprotection in aged rats

    DEFF Research Database (Denmark)

    Bennion, Douglas M; Isenberg, Jacob D; Harmel, Allison T

    2017-01-01

    Activation of the angiotensin II type 2 receptor (AT2R) by administration of Compound 21 (C21), a selective AT2R agonist, induces neuroprotection in models of ischemic stroke in young adult animals. The mechanisms of this neuroprotective action are varied, and may include direct and indirect effe...... disease. Further, it appears that this sustained neuroprotection is likely due to a mix of both direct and indirect effects stemming from selective activation of AT2Rs on neurons or other cells besides astrocytes and microglia.......Activation of the angiotensin II type 2 receptor (AT2R) by administration of Compound 21 (C21), a selective AT2R agonist, induces neuroprotection in models of ischemic stroke in young adult animals. The mechanisms of this neuroprotective action are varied, and may include direct and indirect...... effects of AT2R activation. Our objectives were to assess the long-term protective effects of post-stroke C21 treatments in a clinically-relevant model of stroke in aged rats and to characterize the cellular localization of AT2Rs in the mouse brain of transgenic reporter mice following stroke...

  19. Angiotensin II type 1 receptor antagonists in the treatment of hypertension in elderly patients: focus on patient outcomes

    Directory of Open Access Journals (Sweden)

    Artavazd Tadevosyan

    2011-01-01

    Full Text Available Artavazd Tadevosyan1, Eric J MacLaughlin2, Vardan T Karamyan31Departments of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, QC, Canada; 2Department of Pharmacy Practice, 3Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USAAbstract: Hypertension in the elderly is one of the main risk factors of cardiovascular and cerebrovascular diseases. Knowledge regarding the mechanisms of hypertension and specific considerations in managing hypertensive elderly through pharmacological intervention(s is fundamental to improving clinical outcomes. Recent clinical studies in the elderly have provided evidence that angiotensin II type 1 (AT1 receptor antagonists can improve clinical outcomes to a similar or, in certain populations, an even greater extent than other classical arterial blood pressure-lowering agents. This newer class of antihypertensive agents presents several benefits, including potential for improved adherence, excellent tolerability profile with minimal first-dose hypotension, and a low incidence of adverse effects. Thus, AT1 receptor antagonists represent an appropriate option for many elderly patients with hypertension, type 2 diabetes, heart failure, and/or left ventricular dysfunction.Keywords: angiotensin II, ARB, cardiovascular disease, antihypertensive therapy, elderly

  20. Angiotensin type 1 receptor antagonist losartan, reduces MPTP-induced degeneration of dopaminergic neurons in substantia nigra

    Directory of Open Access Journals (Sweden)

    Jhaveri Vimal V

    2007-01-01

    Full Text Available Abstract Background Recent attention has focused on understanding the role of the brain-renin-angiotensin-system (RAS in stroke and neurodegenerative diseases. Direct evidence of a role for the brain-RAS in Parkinson's disease (PD comes from studies demonstrating the neuroprotective effect of RAS inhibitors in several neurotoxin based PD models. In this study, we show that an antagonist of the angiotensin II (Ang II type 1 (AT1 receptor, losartan, protects dopaminergic (DA neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP toxicity both in primary ventral mesencephalic (VM cultures as well as in the substantia nigra pars compacta (SNpc of C57BL/6 mice (Fig. 1. Results In the presence of exogenous Ang II, losartan reduced MPP+ (5 μM induced DA neuronal loss by 72% in vitro. Mice challenged with MPTP showed a 62% reduction in the number of DA neurons in the SNpc and a 71% decrease in tyrosine hydroxylase (TH immunostaining of the striatum, whereas daily treatment with losartan lessened MPTP-induced loss of DA neurons to 25% and reduced the decrease in striatal TH+ immunostaining to 34% of control. Conclusion Our study demonstrates that the brain-RAS plays an important neuroprotective role in the MPTP model of PD and points to AT1 receptor as a potential novel target for neuroprotection.

  1. Association of Polymorphisms in Angiotensin-converting Enzyme and Type 1 AngiotensinReceptor Genes with Coronary Heart Disease and the Severity of Coronary Artery Stenosis

    Institute of Scientific and Technical Information of China (English)

    QIU Chunguang; HAN Zhanying; LU Wenjie; ZHANG Cuntai

    2007-01-01

    To explore the relation of angiotensin-converting enzyme (ACE) and angiotensintype 1 receptor (AT1R) gene polymorphism with coronary heart disease (CHD) and the severity of coronary artery stenosis, 130 CHD patients who underwent coronary angiography were examined for the number of affected coronary vessels (≥75% stenosis) and coronary Jeopardy score. The inser- tion/deletion of ACE gone polymorphism and ATIR gene polymorphism (an A→C transversion at nucleotide position 1166) were detected by using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) in CHD patients and 90 healthy serving as controls. The re- sults showed that DD genotype and of ACE were more frequent in CHD patients than that in control group (38.5% vs 14.4%, P<0.001). The frequency of the AT1R A/C genotypes did not differ between the patients and the controls (10% vs 13.1%, P0.05). The relative risk associated with the ACE-DD was increased by ATIR-AC genotype. Neither the number of affected coronary vessels nor the coro-nary score differed among the ACE I/D genotypes (P0.05). But the number of affected coronary vessels and the coronary score were significantly greater in the patients with the AT1R-AC genotype than in those with the AA genotype (P<0.05). In conclusion, DD genotype may he risk factor for CHD and MI in Chinese people, and is not responsible for the development of the coronary artery stenosis. The AT1R-C allele may increase the relative risk associated with the ACE-DD genotype, and may be involved in the development of the stenosis of coronary artery.

  2. Effects of angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers on lymphangiogenesis of gastric cancer in a nude mouse model

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; CAI Shi-rong; ZHANG Chang-hua; HE Yu-long; ZHAN Wen-hua; WU Hui; PENG Jian-jun

    2008-01-01

    Background Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II type 1 receptor blockers (ARB) can inhibit tumor growth by inhibition of angiogenesis.This study was designed to study the anticancer effects of ACEI and ARB on tumor growth and lymphangiogenesis in an implanted gastric cancer mouse model.Methods A model of gastric cancer was established by subcutaneously inoculating human gastric cancer cell line SGC-7901 into 60 nude mice.One week later,all mice were randomly divided into 5 groups.A control group received physiologic saline once daily for 21 days.Mice in the 4 treatment groups received one of the following agents by gavage once daily for 21 days:perindopril,2 mg/kg;captopril,5 mg/kg;Iosartan,50 mg/kg;or valsartan,40 mg/kg.Twenty-one clays after treatment,all the mice were sacrificed and the tumors were removed.Tumor sections were processed,and immunohistochemical methods were used to observe the expressions of vascular endothelial growth factor C (VEGF-C),matrix metalloproteinase 7 (MMP-7),and lymphatic microvessel density (LMVD).Results Tumor volume was significantly inhibited in all ACEI and ARB groups,compared with the control group (all P <0.01).LMVD in the ACEI and ARB groups was also significantly lower than that of the control group (all P<0.01).In the ACEI groups,the expressions of VEGF-C and MMP-7 were both significantly decreased,compared with the control group (all P<0.05).In the ARB groups,expression of VEGF-C was significantly decreased compared with the control group (all P<0.05).However,no significant difference was found in the expression of MMP-7 between ARB groups and the control group.Conclusion In a mouse model,ACEI and ARB might inhibit gastric cancer tumor growth by suppressing lymphangiogenesis.

  3. Circulating angiotensin type II receptor: Possible marker for antibody mediated rejection after renal transplantation?

    Science.gov (United States)

    Kimball, Pamela M; Gupta, Gaurav; McDougan, Felecia

    2017-06-11

    Presence of antibody [Ab] against angiotensin receptor [AT1R] indicates heightened risk for antibody mediated rejection [AMR] after transplantation but is insufficient as a marker. We speculated AT1R might be released systemically because of AMR and might be a useful biomarker. AT1R was measured in blood from 73 Normals and 72 renal patients pre- and post-transplantation. Patients were stratified as AMR-free [Gp1], AMR1yr [Gp3]. AT1R was higher [13±26vs.367±537, p<0.01)] and more prevalent [20% vs. 92%, p<0.01] among renal patients than Normals. Pretransplant levels were similar [p=ns] between groups. One-year posttransplant levels approached [p<0.01] normalcy for Gps1+3 but spiked during AMR and remained elevated [155±58, p<0.01] for 50% Gp2 patients. One-year AT1R levels were higher among subsequent graft failures than surviving grafts [171±267vs. 38±50, p<0.01]. Pretransplant AT1R was abnormally elevated: possibly indicating ongoing tissue injury. Pretransplant AT1R didn't predict risk for AMR. However, AT1R spiked during early AMR and sustained elevations were associated with poorer outcomes. Copyright © 2017. Published by Elsevier Inc.

  4. Keeping pace with ACE: are ACE inhibitors and angiotensin II type 1 receptor antagonists potential doping agents?

    Science.gov (United States)

    Wang, Pei; Fedoruk, Matthew N; Rupert, Jim L

    2008-01-01

    In the decade since the angiotensin-converting enzyme (ACE) gene was first proposed to be a 'human gene for physical performance', there have been numerous studies examining the effects of ACE genotype on physical performance phenotypes such as aerobic capacity, muscle function, trainability, and athletic status. While the results are variable and sometimes inconsistent, and corroborating phenotypic data limited, carriers of the ACE 'insertion' allele (the presence of an alu repeat element in intron 16 of the gene) have been reported to have higher maximum oxygen uptake (VO2max), greater response to training, and increased muscle efficiency when compared with individuals carrying the 'deletion' allele (absence of the alu repeat). Furthermore, the insertion allele has been reported to be over-represented in elite athletes from a variety of populations representing a number of endurance sports. The mechanism by which the ACE insertion genotype could potentiate physical performance is unknown. The presence of the ACE insertion allele has been associated with lower ACE activity (ACEplasma) in number of studies, suggesting that individuals with an innate tendency to have lower ACE levels respond better to training and are at an advantage in endurance sporting events. This could be due to lower levels of angiotensin II (the vasoconstrictor converted to active form by ACE), higher levels of bradykinin (a vasodilator degraded by ACE) or some combination of the two phenotypes. Observations that individuals carrying the ACE insertion allele (and presumably lower ACEplasma) have an enhanced response to training or are over-represented amongst elite athletes raises the intriguing question: would individuals with artificially lowered ACEplasma have similar training or performance potential? As there are a number of drugs (i.e. ACE inhibitors and angiotensin II type 1 receptor antagonists [angiotensin receptor blockers--ARBs]) that have the ability to either reduce ACEplasma

  5. Human GRK4γ142V Variant Promotes Angiotensin II Type I Receptor-Mediated Hypertension via Renal Histone Deacetylase Type 1 Inhibition.

    Science.gov (United States)

    Wang, Zheng; Zeng, Chunyu; Villar, Van Anthony M; Chen, Shi-You; Konkalmatt, Prasad; Wang, Xiaoyan; Asico, Laureano D; Jones, John E; Yang, Yu; Sanada, Hironobu; Felder, Robin A; Eisner, Gilbert M; Weir, Matthew R; Armando, Ines; Jose, Pedro A

    2016-02-01

    The influence of a single gene on the pathogenesis of essential hypertension may be difficult to ascertain, unless the gene interacts with other genes that are germane to blood pressure regulation. G-protein-coupled receptor kinase type 4 (GRK4) is one such gene. We have reported that the expression of its variant hGRK4γ(142V) in mice results in hypertension because of impaired dopamine D1 receptor. Signaling through dopamine D1 receptor and angiotensin II type I receptor (AT1R) reciprocally modulates renal sodium excretion and blood pressure. Here, we demonstrate the ability of the hGRK4γ(142V) to increase the expression and activity of the AT1R. We show that hGRK4γ(142V) phosphorylates histone deacetylase type 1 and promotes its nuclear export to the cytoplasm, resulting in increased AT1R expression and greater pressor response to angiotensin II. AT1R blockade and the deletion of the Agtr1a gene normalize the hypertension in hGRK4γ(142V) mice. These findings illustrate the unique role of GRK4 by targeting receptors with opposite physiological activity for the same goal of maintaining blood pressure homeostasis, and thus making the GRK4 a relevant therapeutic target to control blood pressure.

  6. A different role of angiotensin II type 1a receptor in the development and hypertrophy of plantaris muscle in mice.

    Science.gov (United States)

    Zempo, Hirofumi; Suzuki, Jun-Ichi; Ogawa, Masahito; Watanabe, Ryo; Isobe, Mitsuaki

    2016-02-01

    The role of angiotensin II type 1 (AT1) receptors in muscle development and hypertrophy remains unclear. This study was designed to reveal the effects that a loss of AT1 receptors has on skeletal muscle development and hypertrophy in mice. Eight-week-old male AT1a receptor knockout (AT1a(-/-)) mice were used for this experiment. The plantaris muscle to body weight ratio, muscle fiber cross-sectional area, and number of muscle fibers of AT1a(-/-) mice was significantly greater than wild type (WT) mice in the non-intervention condition. Next, the functional overload (OL) model was used to induce plantaris muscle hypertrophy by surgically removing the two triceps muscles consisting of the calf, soleus, and gastrocnemius muscles in mice. After 14 days of OL intervention, the plantaris muscle weight, the amount of fiber, and the fiber area increased. However, the magnitude of the increment of plantaris weight was not different between the two strains. Agtr1a mRNA expression did not change after OL in WT muscle. Actually, the Agt mRNA expression level of WT-OL was lower than WT-Control (C) muscle. An atrophy-related gene, atrogin-1 mRNA expression levels of AT1a(-/-)-C, WT-OL, and AT1a(-/-)-OL muscle were lower than that of WT-C muscle. Our findings suggest that AT1 receptor contributes to plantaris muscle development via atrogin-1 in mice.

  7. Polymorphism in the angiotensin II type 1 receptor (AGTR1) is associated with age at diagnosis in pulmonary arterial hypertension.

    Science.gov (United States)

    Chung, Wendy K; Deng, Liyong; Carroll, J Sheila; Mallory, Nicole; Diamond, Beverly; Rosenzweig, Erika Berman; Barst, Robyn J; Morse, Jane H

    2009-04-01

    Pulmonary arterial hypertension (PAH) is a rare, lethal disease associated with single gene disorders, connective tissue disease, exposures to anorexigens, and often, idiopathic etiology. Genes can modify the risk of PAH: (1) monogenic disorders associated with PAH are incompletely penetrant, and (2) not all patients with associated conditions at increased risk for PAH develop the disease. The renin angiotensin aldosterone system (RAAS) provides a set of candidate genes that could modulate pulmonary vascular disease similar to its effects on renal and peripheral vasculature. We studied 247 patients with PAH, comprising 177 with idiopathic PAH (IPAH), 63 with PAH/connective tissue disease (CTD), and 7 with PAH associated with anorexigens. Patients were genotyped for 5 common polymorphisms in angiotensinogen (AGT), angiotensin-converting enzyme (ACE), cardiac chymase A (CMA1), angiotensin II type 1 receptor (AGTR1), and aldosterone synthase (CYP11B2). Genotypes were tested for associations with age at diagnosis, hemodynamic parameters at diagnosis, and/or response to acute pulmonary vasodilator testing at diagnosis. Associations were demonstrated for AGTR1 and age at diagnosis in IPAH (p = 0.005). Homozygotes for the 1166C allele (n = 13) were associated with an age at diagnosis 26 years later than those with A/A (n = 139) or A/C (n = 90) genotypes. No associations were demonstrated for AGT, ACE, CMA1, or CYP11B2. The 1166C polymorphism in AGTR1 appears to be associated with a later age at diagnosis in IPAH, suggesting that this pathway could be involved in the biologic variability that is known to occur in PAH.

  8. MicroRNA-410 functions as a tumor suppressor by targeting angiotensin II type 1 receptor in pancreatic cancer.

    Science.gov (United States)

    Guo, Rende; Gu, Jianhua; Zhang, Zhibin; Wang, Yi; Gu, Chuan

    2015-01-01

    MicroRNAs (miRNAs) act as key regulators of gene expression in diverse biological processes and are intimately involved in tumorigenesis. However, the underlying molecular mechanisms of miR-410 in pancreatic cancer remain poorly understood. In this study, we found that miR-410 overexpression suppressed pancreatic cancer cell growth in vitro and in vivo as well as cell invasion and migration. miR-410 also resulted in G1/S cell-cycle arrest. We then showed that angiotensin II type 1 receptor (AGTR1) was a direct target of miR-410, with miR-410 suppressing AGTR1 expression levels. In contrast, inhibition of miR-410 increased the expression of AGTR1. Silencing of AGTR1 inhibited cell growth and invasion, similar to miR-410 overexpression. In addition, we found that the induction of vascular endothelial growth factor and the activation of the ERK signaling pathway by angiotensin II were blocked by miR-410, similar to the angiotensin II inhibitor losartan. miR-410 overexpression inhibited angiogenesis in mice through the repression of CD31 expression. ERK pathway knockdown suppressed pancreatic cancer cell proliferation, invasion, and angiogenesis. Finally, we found that miR-410 was downregulated in pancreatic cancer tissues compared to adjacent nontumor tissues, whereas AGTR1 was upregulated in pancreatic cancer tissues. Pearson correlation analysis showed that miR-410 and AGTR1 were inversely expressed. In conclusion, our data indicate that miR-410 suppresses pancreatic cancer growth, cell invasion, migration, and angiogenesis via the downregulation of AGTR1, acting as a tumor-suppressive miRNA. In addition, our results suggest that miR-410 is a potential diagnostic biomarker and therapeutic target for patients with pancreatic cancer. © 2015 International Union of Biochemistry and Molecular Biology.

  9. Angiotensin II receptors in testes

    Energy Technology Data Exchange (ETDEWEB)

    Millan, M.A.; Aguilera, G.

    1988-05-01

    Receptors for angiotensin II (AII) were identified and characterized in testes of rats and several primate species. Autoradiographic analysis of the binding of 125I-labeled (Sar1,Ile8)AII to rat, rhesus monkey, cebus monkey, and human testicular slide-mounted frozen sections indicated specific binding to Leydig cells in the interstitium. In rat collagenase-dispersed interstitial cells fractionated by Percoll gradient, AII receptor content was parallel to that of hCG receptors, confirming that the AII receptors are in the Leydig cells. In rat dispersed Leydig cells, binding was specific for AII and its analogs and of high affinity (Kd, 4.8 nM), with a receptor concentration of 15 fmol/10(6) cells. Studies of AII receptors in rat testes during development reveals the presence of high receptor density in newborn rats which decreases toward the adult age (4934 +/- 309, 1460 +/- 228, 772 +/- 169, and 82 +/- 12 fmol/mg protein at 5, 15, 20, and 30 days of age, respectively) with no change in affinity. At all ages receptors were located in the interstitium, and the decrease in binding was parallel to the decrease in the interstitial to tubular ratio observed with age. AII receptor properties in membrane-rich fractions from prepuberal testes were similar in the rat and rhesus monkey. Binding was time and temperature dependent, reaching a plateau at 60 min at 37 C, and was increased by divalent cations, EGTA, and dithiothreitol up to 0.5 mM. In membranes from prepuberal monkey testes, AII receptors were specific for AII analogs and of high affinity (Kd, 4.2 nM) with a receptor concentration of 7599 +/- 1342 fmol/mg protein. The presence of AII receptors in Leydig cells in rat and primate testes in conjunction with reports of the presence of other components of the renin-angiotensin system in the testes suggests that the peptide has a physiological role in testicular function.

  10. A Novel Angiotensin Type I Receptor Antagonist, Fimasartan, Prevents Doxorubicin-induced Cardiotoxicity in Rats.

    Science.gov (United States)

    Chang, Sung-A; Lim, Byung-Kwan; Lee, You Jung; Hong, Mi-Kyung; Choi, Jin-Oh; Jeon, Eun-Seok

    2015-05-01

    Angiotensin receptor blockers (ARBs) have organ-protective effects in heart failure and may be also effective in doxorubicin-induced cardiomyopathy (DOX-CMP); however, the efficacy of ARBs on the prevention of DOX-CMP have not been investigated. We performed a preclinical experiment to evaluate the preventive effect of a novel ARB, fimasartan, in DOX-CMP. All animals underwent echocardiography and were randomly assigned into three groups: treated daily with vehicle (DOX-only group, n=22), 5 mg/kg of fimasartan (Low-fima group, n=22), and 10 mg/kg of fimasartan (High-fima group, n=19). DOX was injected once a week for six weeks. Echocardiography and hemodynamic assessment was performed at the 8th week using a miniaturized conductance catheter. Survival rate of the High-fima group was greater (100%) than that of the Low-fima (75%) and DOX-only groups (50%). Echocardiography showed preserved left ventricular (LV) ejection fraction in the High-fima group, but not in the DOX-only group (P=0.002). LV dimensions increased in the DOX-only group; however, remodeling was attenuated in the Low-fima and High-fima groups. Hemodynamic assessment showed higher dP/dt in the High-fima group compared with the DOX-only group. A novel ARB, fimasartan, may prevent DOX-CMP and improve survival rate in a dose-dependent manner in a rat model of DOX-CMP and could be a treatment option for the prevention of DOX-CMP.

  11. Altered functioning of both renal dopamine D1 and angiotensin II type 1 receptors causes hypertension in old rats.

    Science.gov (United States)

    Chugh, Gaurav; Lokhandwala, Mustafa F; Asghar, Mohammad

    2012-05-01

    Activation of renal dopamine D1 (D1R) and angiotensin II type 1 receptors (AT(1)Rs) influences the activity of proximal tubular sodium transporter Na,K-ATPase and maintains sodium homeostasis and blood pressure. We reported recently that diminished D1R and exaggerated AT(1)R functions are associated with hypertension in old Fischer 344 × Brown Norway F1 (FBN) rats, and oxidative stress plays a central role in this phenomenon. Here we studied the mechanisms of age-associated increase in oxidative stress on diminished D1R and exaggerated AT(1)R functions in the renal proximal tubules of control and antioxidant Tempol-treated adult and old FBN rats. Although D1R numbers and D1R agonist SKF38393-mediated stimulation of [(35)S]-GTPγS binding (index of D1R activation) were lower, G protein-coupled receptor kinase 4 (kinase that uncouples D1R) levels were higher in old FBN rats. Tempol treatment restored D1R numbers and G protein coupling and reduced G protein-coupled receptor kinase 4 levels in old FBN rats. Angiotensin II-mediated stimulation of [(35)S]-GTPγS binding and Na,K-ATPase activity were higher in old FBN rats, which were also restored with Tempol treatment. We also measured renal AT(1)R function in adult and old Fischer 344 (F344) rats, which, despite exhibiting an age-related increase in oxidative stress and diminished renal D1R function, are normotensive. We found that diuretic and natriuretic responses to candesartan (indices of AT(1)R function) were similar in F344 rats, a likely explanation for the absence of age-associated hypertension in these rats. Perhaps, alterations in both D1R (diminished) and AT(1)R (exaggerated) functions are necessary for the development of age-associated hypertension, as seen in old FBN rats.

  12. Increased expression of angiotensin II type 1 receptor (AGTR1) in heart transplant recipients with recurrent rejection.

    Science.gov (United States)

    Yamani, Mohamad H; Cook, Daniel J; Rodriguez, E Rene; Thomas, Dawn M; Gupta, Sandeep; Alster, Joan; Taylor, David O; Hobbs, Robert; Young, James B; Smedira, Nicholas; Starling, Randall C

    2006-11-01

    Angiotensin II receptor sub-type 1 (AGTR1) plays an important role in the regulation of the cellular immune process. We hypothesized that recurrent acute rejection is associated with increased gene expression of AGTR1 in human heart transplantation. We identified a group of 14 heart transplant recipients who had recurrent acute cellular rejection (RAR), defined as three consecutive episodes of acute rejection (Grade > or =3A). These patients were matched to a control group (n = 15). mRNA gene expression of AGTR1 was measured in heart biopsy specimens of controls at 1 week post-transplant. AGTR1 mRNA was determined serially in the RAR group at baseline, each rejection episode, and after resolution of rejection. Angiotensin-converting enzyme (ACE) polymorphism was also evaluated. Both the control and RAR groups had similar mRNA AGTR1 expression at baseline. Compared with baseline, the RAR group had significantly increased mRNA expression of AGTR1 at the first episode of rejection (9-fold, p AGTR1 expression was decreased significantly (p AGTR1 in response to recurrent cellular rejection. Up-regulation of AGTR1 responds to treatment of rejection but not to complete recovery, a phenomenon that may potentially explain the link between rejection and subsequent clinical outcome.

  13. G protein-independent effects of the Angiotensin II type I receptor

    DEFF Research Database (Denmark)

    Christensen, Gitte Lund

    2010-01-01

    Angiotensin II type 1 receptoren (AT1R) er en syv transmembranreceptor (7TMR) og et vigtigt terapeutisk target indenfor kardiovaskulær medicin. AT1R er gennem de seneste år blevet en model for det concept, at 7TMRer kan signalere via andre og mindre velbeskrevne signalveje end de G protein...... afhængige. Skæve agonister, som blokerer G protein signaleringen mens de samtidig aktiverer de G protein uafhængige signaleringsveje er blevet brugt til at beskrive de to hovedgrene i AT1R signaleringen i cellemodelsystemer. Vi påviser at denne farmakologiske differentiering af de to signalveje er relevant...... i primære kardiomyocytter og hele hjerter og endvidere at skæve agonister kan adskille skadelig hypertrofisk vækst fra ønskelig fornyelse af hjertemuskelceller. Deruover har fokus i denne PhD afhandling været på at beskrive de G protein uafhængige effekter af AT1R aktivering vha. den skæve agonist...

  14. initial angiotensin receptor blockade-induced decrease in albuminuria is associated with long-term renal outcome in type 2 diabetic patients with microalbuminuria

    DEFF Research Database (Denmark)

    Hellemons, Merel E; Persson, Frederik; Bakker, Stephan J L

    2011-01-01

    We aimed to investigate the individual impact of initial responses in urinary albumin excretion (UAE) and systolic blood pressure (SBP) to angiotensin II receptor blocker (ARB) treatment on long-term renal outcome in patients with type 2 diabetes and microalbuminuria....

  15. Impaired spatial memory and altered dendritic spine morphology in angiotensin II type 2 receptor-deficient mice.

    Science.gov (United States)

    Maul, Björn; von Bohlen und Halbach, Oliver; Becker, Axel; Sterner-Kock, Anja; Voigt, Jörg-Peter; Siems, Wolf-Eberhard; Grecksch, Gisela; Walther, Thomas

    2008-05-01

    Mental retardation is the most frequent cause of serious handicap in children and young adults. Mutations in the human angiotensin II type 2 receptor (AT2) have been implicated in X-linked forms of mental retardation. We here demonstrate that mice lacking the AT2 receptor gene are significantly impaired in their performance in a spatial memory task and in a one-way active avoidance task. As no difference was observed between the genotypes in fear conditioning, the detected deficit in spatial memory may not relate to fear. Notably, receptor knockout mice showed increased motility in an activity meter and elevated plus maze. Importantly, these mice are characterized by abnormal dendritic spine morphology and length, both features also found to be associated with some cases of mental retardation. These findings suggest a crucial role of AT2 in normal brain function and that dysfunction of the receptor has impact on brain development and ultrastructural morphology with distinct consequences on learning and memory.

  16. Angiotensin type 1 receptor A1166C polymorphism and systemic lupus erythematosus: correlation with cellular immunity and oxidative stress markers.

    Science.gov (United States)

    Baniamerian, H; Bahrehmand, F; Vaisi-Raygani, A; Rahimi, Z; Pourmotabbed, T

    2017-01-01

    Angiotensin II, one of the rennin-angiotensin system components, is important in the cardiovascular hemodynamic and plays an important role in the development of cardiovascular disease in systemic lupus erythematosus (SLE) patients. The angiotensin II, through interaction with angiotensin II type 1 receptor (AGTR1), promotes proliferation, inflammation and fibrosis. The single nucleotide polymorphism of the AGTR1 (dbSNP: rs5186) gene can be associated with development and progression of SLE disease. The aims of this study were to compare the frequency of AGTR1 rs5186 in SLE patients with healthy individuals and to evaluate possible association between AGTR1 A1166C gene polymorphism and serum level of lipids, neopterin and malondialdehyde in SLE patients from a population of West Iran. One hundred SLE patients and 98 healthy subjects were studied. The AGTR1 A1166C polymorphism was detected by polymerase chain reaction- restriction fragment length polymorphism method and the serum lipid profile was obtained by enzymatic method. Neopterin and malondialdehyde were detected using high-performance liquid chromatography. We did not detect significant association between AGTR1 A1166C polymorphism and the risk of SLE. The levels of triglyceride (225 ± 118 mg/dl), neopterin (30 ± 24 nmol/l) and malondialdehyde (25 ± 9.6 nmol/l) in SLE patients were significantly higher than those in control subjects (139 ± 56 mg/dl, p = 0.03, 6.4 ± 2, p = 0.03, 9.4 ± 2.5 nmol/l, p = 0.01, respectively). Individuals with AGTR1 AC + CC genotype had higher levels of total cholesterol and malondialdehyde compared with those with AGTR1 AA genotype. SLE patients with either AGTR1 AA or AGTR1AC + CC genotype had significantly higher malondialdehyde or neopterin levels compared with the corresponding control subjects. In conclusion, although the present study did not find any association between AGTR1 A1166C polymorphism and the risk of SLE

  17. Role of angiotensin II type 1 receptor antagonists in the treatment of hypertension in patients aged >or=65 years.

    Science.gov (United States)

    Gradman, Alan H

    2009-01-01

    Systolic blood pressure (SBP) increases with age, and hypertension affects approximately two-thirds of adults in the US aged >60 years. Blood pressure (BP) increases as a consequence of age-related structural changes in large arteries, which lead to loss of elasticity and reduced vascular compliance. Increased pulse wave velocity augments SBP, resulting in a high prevalence of isolated systolic hypertension. Because age itself elevates cardiovascular risk, effective treatment of hypertension in an older (aged >or=65 years) patient population prevents many more events per 1000 patients treated than treatment of younger hypertensive patients. Recommendations for treating hypertension are similar in older patients compared with the general population. The Seventh Report of the Joint National Committee on Detection, Prevention, Evaluation, and Treatment of High Blood Pressure recommends target BP goals of heart failure. Randomized clinical trials have demonstrated the efficacy of calcium channel antagonists (calcium channel blockers [CCBs]), low-dose diuretics, ACE inhibitors and angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) in reducing the risk of stroke and other adverse cardiovascular outcomes in older patients; beta-adrenoceptor antagonists are less effective in terms of endpoint reduction. The majority of older patients require two or more drugs to achieve BP goals. Despite active treatment, half of these patients do not achieve target BP, in part because of the reluctance of physicians to intensify treatment, a phenomenon referred to as 'clinical inertia'. ARBs are effective antihypertensive agents in older patients and have been shown to reduce cardiovascular endpoints in patients with hypertension, diabetic nephropathy, cerebrovascular disease and heart failure. ARBs produce additive BP reduction when combined with diuretics or CCBs. They also have the advantage of placebo-like tolerability, and this contributes favourably to

  18. Antihypertensive, insulin-sensitising and renoprotective effects of a novel, potent and long-acting angiotensin II type 1 receptor blocker, azilsartan medoxomil, in rat and dog models.

    Science.gov (United States)

    Kusumoto, Keiji; Igata, Hideki; Ojima, Mami; Tsuboi, Ayako; Imanishi, Mitsuaki; Yamaguchi, Fuminari; Sakamoto, Hiroki; Kuroita, Takanobu; Kawaguchi, Naohiro; Nishigaki, Nobuhiro; Nagaya, Hideaki

    2011-11-01

    The pharmacological profile of a novel angiotensin II type 1 receptor blocker, azilsartan medoxomil, was compared with that of the potent angiotensin II receptor blocker olmesartan medoxomil. Azilsartan, the active metabolite of azilsartan medoxomil, inhibited the binding of [(125)I]-Sar(1)-I1e(8)-angiotensin II to angiotensin II type 1 receptors. Azilsartan medoxomil inhibited angiotensin II-induced pressor responses in rats, and its inhibitory effects lasted 24h after oral administration. The inhibitory effects of olmesartan medoxomil disappeared within 24h. ID(50) values were 0.12 and 0.55 mg/kg for azilsartan medoxomil and olmesartan medoxomil, respectively. In conscious spontaneously hypertensive rats (SHRs), oral administration of 0.1-1mg/kg azilsartan medoxomil significantly reduced blood pressure at all doses even 24h after dosing. Oral administration of 0.1-3mg/kg olmesartan medoxomil also reduced blood pressure; however, only the two highest doses significantly reduced blood pressure 24h after dosing. ED(25) values were 0.41 and 1.3mg/kg for azilsartan medoxomil and olmesartan medoxomil, respectively. In renal hypertensive dogs, oral administration of 0.1-1mg/kg azilsartan medoxomil reduced blood pressure more potently and persistently than that of 0.3-3mg/kg olmesartan medoxomil. In a 2-week study in SHRs, azilsartan medoxomil showed more stable antihypertensive effects than olmesartan medoxomil and improved the glucose infusion rate, an indicator of insulin sensitivity, more potently (≥ 10 times) than olmesartan medoxomil. Azilsartan medoxomil also exerted more potent antiproteinuric effects than olmesartan medoxomil in Wistar fatty rats. These results suggest that azilsartan medoxomil is a potent angiotensin II receptor blocker that has an attractive pharmacological profile as an antihypertensive agent.

  19. Activation of angiotensin II type 1 receptors in the median preoptic nucleus induces a diuretic and natriuretic response in rats

    Institute of Scientific and Technical Information of China (English)

    Yuan Gao; Lei Luo; Hong Liu

    2009-01-01

    Objective: To investigate the effect of activation of angiotensin II (AngII) type 1 (ATI) receptors in the median preoptic nucleus (MnPO) of rats on renal sodium excretion. Methods: After anesthesia, the rats were injected into the MnPO via an implanted cannula. Urine samples were collected via a bladder cannula, and the urine sodium concentration was assayed with flame spectrophotometry. The serum level of endogenous digitalis-like factor (EDLF) and Na+,K+-ATPase activity in the renal cortex tissue were assayed respectively with a radioimmunoassay and with an ammonium molybdophosphate-based kit. Results: Both the urinary volume and the sodium excretion peaked 60 min after Angll was administered into the MnPO. The responses were accompanied by an increase in serum EDLF and a decrease in Na+,K+-ATPase activity in the renal cortex. The responses of diuresis and natriuresis, as well as an increase in serum EDLF and a decrease in Na+,K+-ATPase activity in the renal cortex induced by MnPO adminstration with AngII were inhibited by pior treatment with the AngII receptor blocking agent losartan into the MnPO. Conclusion: These results suggest that activation of ATI receptors in the MnPO of rat induces diuretic and natriuretic responses. The responses are associated with an increase release of EDLF and with the inhibition of Na+,K+-ATPase activity in renal cortex tissue.

  20. Increased angiotensin II type 1 receptor expression in temporal arteries from patients with giant cell arteritis

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Malmsjö, Malin; Andersson, Christina

    2009-01-01

    PURPOSE: Currently, giant cell arteritis (GCA) is primarily treated with corticosteroids or immunomodulating agents, but there is interest in identifying other noncorticosteroid alternatives. Similarities exist in the injury pathways between GCA and atherosclerosis. Angiotensin II is a vasoactive...... DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article....

  1. Angiotensin II type 2 receptor signaling significantly attenuates growth of murine pancreatic carcinoma grafts in syngeneic mice

    Directory of Open Access Journals (Sweden)

    Troyer Deryl

    2010-02-01

    Full Text Available Abstract Background Pancreatic cancer is one of the most aggressive human malignancies, with a very poor prognosis. To evaluate the effect of angiotensin II (Ang II type 2 receptor (AT2 expression in the host's body on the growth of pancreatic carcinoma, we have investigated the growth of mouse pancreatic ductal carcinoma grafts in syngeneic wild type and AT2 receptor-deficient (AT2-KO mice. Methods The role of AT2 receptor-signaling in stromal cells on the growth of murine pancreatic carcinoma cells (PAN02 was studied using various in vitro and in vivo assays. In vivo cell proliferation, apoptosis, and vasculature in tumors were monitored by Ki-67 immunostaining, TUNEL assay, and von Willebrand factor immunostaining, respectively. In the co-culture study, cell proliferation was measured by MTT cell viability assay. All the data were analyzed using t-test and data were treated as significant when p Results Our results show that the growth of subcutaneously transplanted syngeneic xenografts of PAN02 cells, mouse pancreatic ductal carcinoma cells derived from the C57/BL6 strain, was significantly faster in AT2-KO mice compared to control wild type mice. Immunohistochemical analysis of tumor tissue revealed significantly more Ki-67 positive cells in xenografts grown in AT2-KO mice than in wild type mice. The index of apoptosis is slightly higher in wild type mice than in AT2-KO mice as evaluated by TUNEL assay. Tumor vasculature number was significantly higher in AT2-KO mice than in wild type mice. In vitro co-culture studies revealed that the growth of PAN02 cells was significantly decreased when grown with AT2 receptor gene transfected wild type and AT2-KO mouse-derived fibroblasts. Faster tumor growth in AT2-KO mice may be associated with higher VEGF production in stromal cells. Conclusions These results suggest that Ang II regulates the growth of pancreatic carcinoma cells through modulating functions of host stromal cells; Moreover, Ang II AT2

  2. Angiotensin II acts through the angiotensin 1a receptor to upregulate pendrin

    Science.gov (United States)

    Verlander, Jill W.; Hong, Seongun; Pech, Vladimir; Bailey, James L.; Agazatian, Diana; Matthews, Sharon W.; Coffman, Thomas M.; Le, Thu; Inagami, Tadashi; Whitehill, Florence M.; Weiner, I. David; Farley, Donna B.; Kim, Young Hee

    2011-01-01

    Pendrin is an anion exchanger expressed in the apical regions of B and non-A, non-B intercalated cells. Since angiotensin II increases pendrin-mediated Cl− absorption in vitro, we asked whether angiotensin II increases pendrin expression in vivo and whether angiotensin-induced hypertension is pendrin dependent. While blood pressure was similar in pendrin null and wild-type mice under basal conditions, following 2 wk of angiotensin II administration blood pressure was 31 mmHg lower in pendrin null than in wild-type mice. Thus pendrin null mice have a blunted pressor response to angiotensin II. Further experiments explored the effect of angiotensin on pendrin expression. Angiotensin II administration shifted pendrin label from the subapical space to the apical plasma membrane, independent of aldosterone. To explore the role of the angiotensin receptors in this response, pendrin abundance and subcellular distribution were examined in wild-type, angiotensin type 1a (Agtr1a) and type 2 receptor (Agtr2) null mice given 7 days of a NaCl-restricted diet (Agtr1 inhibitor (candesartan) or vehicle. Both Agtr1a gene ablation and Agtr1 inhibitors shifted pendrin label from the apical plasma membrane to the subapical space, independent of the Agtr2 or nitric oxide (NO). However, Agtr1 ablation reduced pendrin protein abundance through the Agtr2 and NO. Thus angiotensin II-induced hypertension is pendrin dependent. Angiotensin II acts through the Agtr1a to shift pendrin from the subapical space to the apical plasma membrane. This Agtr1 action may be blunted by the Agtr2, which acts through NO to reduce pendrin protein abundance. PMID:21921024

  3. Determinants and Changes Associated with Aldosterone Breakthrough after Angiotensin II Receptor Blockade in Patients with Type 2 Diabetes with Overt Nephropathy

    Science.gov (United States)

    Moranne, Olivier; Bakris, George; Fafin, Coraline; Favre, Guillaume; Pradier, Christian

    2013-01-01

    Summary Background and objectives Inhibition of the renin-angiotensin-aldosterone system decreases proteinuria and slows estimated GFR decline in patients with type 2 diabetes mellitus with overt nephropathy. Serum aldosterone levels may increase during renin-angiotensin-aldosterone system blockade. The determinants and consequences of this aldosterone breakthrough remain unknown. Design, setting, participants, & measurements This study examined the incidence, determinants, and changes associated with aldosterone breakthrough in a posthoc analysis of a randomized study that compared the effect of two angiotensin II receptor blockers in patients with type 2 diabetes mellitus with overt nephropathy. Results Of 567 of 860 participants included in this posthoc analysis, 28% of participants developed aldosterone breakthrough, which was defined by an increase greater than 10% over baseline values of serum aldosterone levels after 1 year of angiotensin II receptor blocker treatment. Factors independently associated with aldosterone breakthrough at 1 year were lower serum aldosterone and potassium levels at baseline, higher decreases in sodium intake, systolic BP, and estimated GFR from baseline to 1 year, and use of losartan versus telmisartan. Aldosterone breakthrough at 6 months was not sustained at 1 year in 69% of cases, and it did not predict estimated GFR decrease and proteinuria increase between 6 months and 1 year. Conclusions Aldosterone breakthrough is a frequent event 1 year after initiating renin-angiotensin-aldosterone system blockade, particularly in participants exposed to intensive lowering of BP with sodium depletion and short-acting angiotensin II receptor blockers. Short-term serum aldosterone level increases at 6 months are not associated with negative kidney outcomes between 6 months and 1 year. PMID:23929924

  4. The ACE-2/Ang1-7/Mas cascade enhances bone structure and metabolism following angiotensin-II type 1 receptor blockade.

    Science.gov (United States)

    Abuohashish, Hatem M; Ahmed, Mohammed M; Sabry, Dina; Khattab, Mahmoud M; Al-Rejaie, Salim S

    2017-07-15

    The renin angiotensin system (RAS) regulates numerous systemic functions and is expressed locally in skeletal tissues. Angiotensin1-7 (Ang1-7) is a beneficial member of the RAS, and the therapeutic effects of a large number of angiotensin receptors blockers (ARBs) are mediated by an Ang1-7-dependent cascade. This study examines whether the reported osteo-preservative effects of losartan are mediated through the angiotensin converting enzyme2 (ACE-2)/Ang1-7/Mas pathway in ovariectomized (OVX) rats. Sham and OVX animals received losartan (10mg/kg/d p.o.) for 6 weeks. A specific Mas receptor blocker (A-779) was delivered via mini-osmotic pumps during the losartan treatment period. Serum and urine bone metabolism biomarker levels were measured. Bone trabecular and cortical morphometry were quantified in distal femurs, whereas mineral contents were estimated in ashed bones, serum and urine. Finally, the expression of RAS components, the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) was determined. Losartan significantly improved the elevated bone metabolism marker levels and altered trabecular and cortical structures in OVX animals, and restored normal urinary and skeletal mineral levels. Mas receptor inhibition significantly abolished all osteo-protective effects of losartan and enhanced the deleterious effects of OVX. Losartan enhanced OVX-induced up-regulation of ACE-1, AngII, angiotensin type 1 (AT1) receptor and RANKL expression, and increased ACE-2, Ang1-7, Mas and OPG expression in OVX animals. However, A-779 significantly eradicated the effects of losartan on RAS components and RANKL/OPG expression. Thus, Ang1-7 are involved in the osteo-preservative effects of losartan via Mas receptor, which may add therapeutic value to this well-known antihypertensive agent. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Angiotensin II type 2 receptor correlates with therapeutic effects of losartan in rats with adjuvant-induced arthritis.

    Science.gov (United States)

    Wang, Di; Hu, Shanshan; Zhu, Jie; Yuan, Jun; Wu, Jingjing; Zhou, Aiwu; Wu, Yujing; Zhao, Wendi; Huang, Qiong; Chang, Yan; Wang, Qingtong; Sun, Wuyi; Wei, Wei

    2013-12-01

    The angiotensin II type 1 receptor (AT1R) blocker losartan ameliorates rheumatoid arthritis (RA) in an experimental model. In RA, AT2R mainly opposes AT1R, but the mechanism by which this occurs still remains obscure. In the present study, we investigated the role of AT2R in the treatment of rats with adjuvant-induced arthritis (AIA) by losartan. Adjuvant-induced arthritis rats were treated with losartan (5, 10 and 15 mg/kg) and methotrexate (MTX; 0.5 mg/kg) in vivo from day 14 to day 28. Arthritis was evaluated by the arthritis index and histological examination. Angiotensin II, tumour necrosis factor-α, and VEGF levels were examined by ELISA. The expression of AT1R and AT2R was detected by western blot and immunohistochemistry analysis. After stimulation with interleukin-1β in vitro, the effects of the AT2R agonist CGP42112 (10(-8) -10(-5)  M) on the chemotaxis of monocytes induced by 10% foetal calf serum (FCS) were analysed by using Transwell assay. Subsequently, the therapeutic effects of CGP42112 (5, 10 and 20 μg/kg) were evaluated in vivo by intra-articular injection in AIA rats. After treatment with losartan, the down-regulation of AT1R expression and up-regulation of AT2R expression in the spleen and synovium of AIA rats correlated positively with reduction in the polyarthritis index. Treatment with CGP42112 inhibited the chemotaxis of AIA monocytes in vitro, possibly because of the up-regulation of AT2R expression. Intra-articular injection with CGP42112 (10 and 20 μg/kg) ameliorated the arthritis index and histological signs of arthritis. In summary, the present study strongly suggests that the up-regulation of AT2R might be an additional mechanism by which losartan exerts its therapeutic effects in AIA rats.

  6. Genetic polymorphism of ACE and the angiotensin II type1 receptor genes in children with chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Elshamaa Manal F

    2011-08-01

    Full Text Available Abstract Aim and Methods We investigated the association between polymorphisms of the angiotensin converting enzyme-1 (ACE-1 and angiotensin II type one receptor (AT1RA1166C genes and the causation of renal disease in 76 advanced chronic kidney disease (CKD pediatric patients undergoing maintenance hemodialysis (MHD or conservative treatment (CT. Serum ACE activity and creatine kinase-MB fraction (CK-MB were measured in all groups. Left ventricular mass index (LVMI was calculated according to echocardiographic measurements. Seventy healthy controls were also genotyped. Results The differences of D allele and DI genotype of ACE were found significant between MHD group and the controls (p = 0.0001. ACE-activity and LVMI were higher in MHD, while CK-MB was higher in CT patients than in all other groups. The combined genotype DD v/s ID+II comparison validated that DD genotype was a high risk genotype for hypertension .~89% of the DD CKD patients were found hypertensive in comparison to ~ 61% of patients of non DD genotype(p = 0.02. The MHD group showed an increased frequency of the C allele and CC genotype of the AT1RA1166C polymorphism (P = 0.0001. On multiple linear regression analysis, C-allele was independently associated with hypertension (P = 0.04. Conclusion ACE DD and AT1R A/C genotypes implicated possible roles in the hypertensive state and in renal damage among children with ESRD. This result might be useful in planning therapeutic strategies for individual patients.

  7. Blockade of Angiotensin II type-1 receptor reduces oxidative stress in adipose tissue and ameliorates adipocytokine dysregulation.

    Science.gov (United States)

    Kurata, A; Nishizawa, H; Kihara, S; Maeda, N; Sonoda, M; Okada, T; Ohashi, K; Hibuse, T; Fujita, K; Yasui, A; Hiuge, A; Kumada, M; Kuriyama, H; Shimomura, I; Funahashi, T

    2006-11-01

    Dysregulated production of adipocytokines may be involved in the development of atherosclerotic cardiovascular disease in metabolic syndrome and chronic kidney disease (CKD) associated with metabolic syndrome. The aim of this study was to determine the effects of treatment with angiotensin II (Ang II) type-1 receptor blocker (ARB) on the regulation of adipocytokines. Olmesartan, an ARB, significantly blunted the age- and body weight-associated falls in plasma adiponectin both in genetically and diet-induced obese mice, without affecting body weight, but had no effect on plasma adiponectin levels in lean mice. Olmesartan also ameliorated dysregulation of adipocytokines in obesity, such as tumor necrosis factor-alpha, plasminogen activator inhibitor-1, monocyte chemotactic protein-1, and serum amyloid A3. Olmesartan significantly reduced reactive oxygen species originating from accumulated fat and attenuated the expression of nicotinamide adenine dinucleotide phospho hydrogenase oxidase subunits in adipose tissue. In cultured adipocytes, olmesartan acted as an antioxidant and improved adipocytokine dysregulation. Our results indicate that blockade of Ang II receptor ameliorates adipocytokine dysregulation and that such action is mediated, at least in part, by targeting oxidative stress in obese adipose tissue. Ang II signaling and subsequent oxidative stress in adipose tissue may be potential targets for the prevention of atherosclerotic cardiovascular disease in metabolic syndrome and also in metabolic syndrome-based CKD.

  8. Brain Angiotensin II Type 1 Receptor Blockade Improves Dairy Blood Pressure Variability via Sympathoinhibition in Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Takuya Kishi

    2015-01-01

    Full Text Available Abnormal blood pressure (BP elevation in early morning is known to cause cardiovascular events. Previous studies have suggested that one of the reasons in abnormal dairy BP variability is sympathoexcitation. We have demonstrated that brain angiotensin II type 1 receptor (AT1R causes sympathoexcitation. The aim of the present study was to investigate whether central AT1R blockade attenuates the excess BP elevation in rest-to-active phase in hypertensive rats or not. Stroke-prone spontaneously hypertensive rats (SHRSP were treated with intracerebroventricular infusion (ICV of AT1R receptor blocker (ARB, oral administration of hydralazine (HYD, or ICV of vehicle (VEH. Telemetric averaged mean BP (MBP was measured at early morning (EM, after morning (AM, and night (NT. At EM, MBP was significantly lower in ARB to a greater extent than in HYD compared to VEH, though MBP at AM was the same in ARB and HYD. At NT, MBP was also significantly lower in ARB than in HYD. These results in MBP were compatible to those in sympathoexcitation and suggest that central AT1R blockade attenuates excess BP elevation in early active phase and continuous BP elevation during rest phase independent of depressor response in hypertensive rats.

  9. Effect of angiotensintypereceptor blocker losartan on bone deterioration in orchiectomized male hypertensive and normotensive rats

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ya-feng; QIN Ling; Timothy CY Kwok; Benson HY Yeung; LI Guo-dong; LIU Fan

    2013-01-01

    Background Epidemiological study showed that the use of angiotensin-converting enzyme inhibitors was associated with higher bone mineral density (BMD) in older people,especially male subjects,which suggested that angiotensin Ⅱ may have a detrimental effect on bone.Therefore,blocking its effect may have a beneficial effect on bone health.Methods Six-month-old male spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) were used.Animals of each model were randomly assigned to the following four groups:Group 1,SHAM operated+vehicle;Group 2,orchidectomy (ORX)+vehicle; Group 3,ORX+low-dose losartan (10 mg.kg-1·d-1); and Group 4,ORX+high-dose losartan (25 mg.kg-1.d-1).Blood pressure was recorded weekly.SHAM and ORX operations were performed,followed by daily losartan and vehicle treatment from day 4 after operation for 16 weeks.Serum and 24-hour urine samples were collected for measurement of bone turnover markers before euthanasia and then the left femur was collected for measurements of BMD and microarchitecture before mechanical test.Results Urine deoxypyridinoline/urine creatinine (DPD/Cr) ratio was significantly higher in SHR than in WKY.BMD and microarchitecture parameters also showed bone deterioration in SHR.After ORX,serum osteocalcin concentration decreased and urine DPD/Cr ratio increased significantly accompanied by a significant decrease in cortical and trabecular BMD and cortical bone thickness in both WKY and SHR.High-dose losartan significantly increased DPD in urine in both SHR and WKY.Apart from marginal favorable changes in bone architecture in WKY treated with high-dose losartan,losartan did not show significant effect on BMD,bone area,bone microarchitecture,and mechanical properties in both SHR and WKY.Conclusion Angiotensintypereceptor blocker losartan was not able to demonstrate significant effect on ORX-induced bone deterioration in both hypertensive and normotensive rats.

  10. Depletion of endothelial or smooth muscle cell-specific angiotensin II type 1a receptors does not influence aortic aneurysms or atherosclerosis in LDL receptor deficient mice.

    Directory of Open Access Journals (Sweden)

    Debra L Rateri

    Full Text Available BACKGROUND: Whole body genetic deletion of AT1a receptors in mice uniformly reduces hypercholesterolemia and angiotensin II-(AngII induced atherosclerosis and abdominal aortic aneurysms (AAAs. However, the role of AT1a receptor stimulation of principal cell types resident in the arterial wall remains undefined. Therefore, the aim of this study was to determine whether deletion of AT1a receptors in either endothelial cells or smooth muscle cells influences the development of atherosclerosis and AAAs. METHODOLOGY/PRINCIPAL FINDINGS: AT1a receptor floxed mice were developed in an LDL receptor -/- background. To generate endothelial or smooth muscle cell specific deficiency, AT1a receptor floxed mice were bred with mice expressing Cre under the control of either Tie2 or SM22, respectively. Groups of males and females were fed a saturated fat-enriched diet for 3 months to determine effects on atherosclerosis. Deletion of AT1a receptors in either endothelial or smooth muscle cells had no discernible effect on the size of atherosclerotic lesions. We also determined the effect of cell-specific AT1a receptor deficiency on atherosclerosis and AAAs using male mice fed a saturated fat-enriched diet and infused with AngII (1,000 ng/kg/min. Again, deletion of AT1a receptors in either endothelial or smooth muscle cells had no discernible effects on either AngII-induced atherosclerotic lesions or AAAs. CONCLUSIONS: Although previous studies have demonstrated whole body AT1a receptor deficiency diminishes atherosclerosis and AAAs, depletion of AT1a receptors in either endothelial or smooth muscle cells did not affect either of these vascular pathologies.

  11. Circadian expression of clock genes and angiotensintype 1 receptors in suprachiasmatic nuclei of sinoaortic-denervated rats

    Institute of Scientific and Technical Information of China (English)

    Hui LI; Ning-ling SUN; Jin WANG; Ai-jun LIU; Ding-feng SU

    2007-01-01

    Aim: To investigate whether the circadian expression of central clock genes and angiotensintype 1 (AT1) receptors was altered in sinoaortic-denervated (SAD)rats. Methods: Male Sprague-Dawley rats underwent sinoaortic denervation or a sham operation at the age of 12 weeks. Four weeks after the operation, blood pressure and heart period were measured in the conscious state in a group of sham-operated (n=10) and SAD rats (n=9). Rest SAD and sham-operated rats were divided into 6 groups (n=6 in each group). The suprachiasmatic nuclei (SCN)tissues were taken every 4 h throughout the day from each group for the determi-nation of the mRNA expression of clock genes (Per2 and Bmall) and the AT1receptor by RT-PCR; the protein expression of Per2 and Bmall was determined by Western blotting. Results: Blood pressure levels in the SAD rats were similar to those of the sham-operated rats. However, blood pressure variabilities signifi-cantly increased in the SAD rats compared with the sham-operated rats. The circadian variation of clock genes in the SCN of the sham-operated rats was char-acterized by a marked increase in the mRNA and protein expression during dark periods. Per2 and Bmall mRNA levels were significantly lower in the SAD rats,especially during dark periods. Western blot analysis confirmed an attenuation of the circadian rhythm of the 2 clock proteins in the SCN of the SAD rats. AT1 receptor mRNA expressions in the SCN were abnormally upregulated in the light phase, changed to a 12-h cycle in the SAD rats. Conclusion: The circadian varia-tion of the 2 central clock genes was attenuated in the SAD rats. Arterial baroreflex dysfunction also induced a disturbance in the expression of AT1 receptors in the SCN.

  12. Absence of angiotensin II type 1 receptor in bone marrow–derived cells is detrimental in the evolution of renal fibrosis

    OpenAIRE

    Nishida, Masashi; FUJINAKA, Hidehiko; Matsusaka, Taiji; Price, James; Kon, Valentina; Fogo, Agnes B; Davidson, Jeffrey M.; Linton, MacRae F.; Fazio, Sergio; Homma, Toshio; Yoshida, Hiroaki; Ichikawa, Iekuni

    2002-01-01

    We examined the in vivo function of the angiotensin II type 1 receptor (Agtr1) on macrophages in renal fibrosis. Fourteen days after the induction of unilateral ureteral obstruction (UUO), wild-type mice reconstituted with marrow lacking the Agtr1 gene (Agtr1–/–) developed more severe interstitial fibrosis with fewer interstitial macrophages than those in mice reconstituted with Agtr1+/+ marrow. These differences were not observed at day 5 of UUO. The expression of profibrotic genes — includi...

  13. Chimeric mice carrying 'regional' targeted deletion of the angiotensin type 1A receptor gene. Evidence against the role for local angiotensin in the in vivo feedback regulation of renin synthesis in juxtaglomerular cells.

    OpenAIRE

    Matsusaka, T; Nishimura, H.; Utsunomiya, H.; Kakuchi, J; Niimura, F; Inagami, T; Fogo, A.; Ichikawa, I

    1996-01-01

    We have developed chimeric mice carrying 'regional' null mutation of the angiotensin type 1A (AT1A) receptor, the AT1 receptor subtype exclusively present in mouse juxtaglomerular (JG) cells. The chimeric mouse (Agtr1a -/- +/+) is made up of wild-type (Agtr1a +/+) cells or cells homozygous for Agtr1a deletion (Agtr1a -/-). In the latter, the AT1A coding exon was replaced with a reporter gene, lacZ. In Agtr1a -/- +/+ mice, these two clones of cells are found to be clustered and display patch...

  14. Angiotensin type 1a receptors on corticotropin-releasing factor neurons contribute to the expression of conditioned fear.

    Science.gov (United States)

    Hurt, R C; Garrett, J C; Keifer, O P; Linares, A; Couling, L; Speth, R C; Ressler, K J; Marvar, P J

    2015-09-01

    Although generally associated with cardiovascular regulation, angiotensin II receptor type 1a (AT1a R) blockade in mouse models and humans has also been associated with enhanced fear extinction and decreased post-traumatic stress disorder (PTSD) symptom severity, respectively. The mechanisms mediating these effects remain unknown, but may involve alterations in the activities of corticotropin-releasing factor (CRF)-expressing cells, which are known to be involved in fear regulation. To test the hypothesis that AT1a R signaling in CRFergic neurons is involved in conditioned fear expression, we generated and characterized a conditional knockout mouse strain with a deletion of the AT1a R gene from its CRF-releasing cells (CRF-AT1a R((-/-)) ). These mice exhibit normal baseline heart rate, blood pressure, anxiety and locomotion, and freeze at normal levels during acquisition of auditory fear conditioning. However, CRF-AT1a R((-/-)) mice exhibit less freezing than wild-type mice during tests of conditioned fear expression-an effect that may be caused by a decrease in the consolidation of fear memory. These results suggest that central AT1a R activity in CRF-expressing cells plays a role in the expression of conditioned fear, and identify CRFergic cells as a population on which AT1 R antagonists may act to modulate fear extinction. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  15. Angiotensin receptor blockers in diabetic nephropathy

    DEFF Research Database (Denmark)

    2004-01-01

    effect on progression of diabetic kidney disease in hypertensive diabetic patients with ACE II and DD genotypes. ARB can prevent/delay development of diabetic nephropathy independently of its beneficial blood pressure-lowering effect in patients with type 2 diabetes and microalbuminuria. Recently, two...... with diabetic nephropathy have demonstrated that angiotensin II receptor blockers (ARB) induce favorable changes in systemic blood pressure, renal hemodynamics, and proteinuria similar to those induced by angiotensin-converting enzyme (ACE) inhibition. Studies have revealed the optimal renoprotective dose...... for some ARBs; however, additional dose titration studies are urgently needed to obtain the maximum benefit of this valuable new class of compounds. The combination of ARB and ACE inhibition is well tolerated and even more effective than monotherapy in reducing systemic blood pressure and albuminuria...

  16. Clinical and Pharmacotherapeutic Relevance of the Double-Chain Domain of the Angiotensin II Type 1 Receptor Blocker Olmesartan

    Science.gov (United States)

    Kiya, Yoshihiro; Miura, Shin-ichiro; Fujino, Masahiro; Imaizumi, Satoshi; Karnik, Sadashiva S.; Saku, Keijiro

    2014-01-01

    We previously reported that the angiotensin II type 1 (AT1) receptor blocker (ARB) olmesartan has two important interactions to evoke inverse agonism (IA). We refer to these interactions as the “double-chain domain (DCD).” Since the clinical pharmacotherapeutic relevance of olmesartan is still unclear, we examined these effects in rats and humans. We analyzed the effects at an advanced stage of renal insufficiency in Dahl salt-sensitive hypertensive rats (Study 1). Rats were fed a high-salt diet from age 9 weeks and arbitrarily assigned to three treatment regimens at age 16 to 21 weeks: olmesartan (2 mg/kg/day) with DCD, a compound related to olmesartan without DCD (6 mg/kg/day, R-239470) or placebo. We also compared the depressor effects of olmesartan to those of other ARBs in patients with essential hypertension (Study 2). Thirty essential hypertensive outpatients who had been receiving ARBs other than olmesartan were recruited for this study. Our protocol was approved by the hospital ethics committee and informed consent was obtained from all patients 12 weeks prior to switching from ARBs other than olmesartan to olmesartan. In Study 1, olmesartan induced a more prominent suppression of the ratio of urinary protein excretion to creatinine at age 21 weeks without lowering blood pressure among the three groups. In Study 2, the depressor effect of olmesartan was significantly stronger than those of other ARBs, which do not contain the DCD. These additive effects by olmesartan may be due to DCD. PMID:20374187

  17. Regulation of angiotensin II type 1 receptor expression in ovarian cancer: a potential role for BRCA1.

    Science.gov (United States)

    Bi, Fang-Fang; Li, Da; Cao, Chen; Li, Chun-Yan; Yang, Qing

    2013-12-09

    Both BRCA1 and angiotensin II type 1 receptor (AGTR1) play a critical role in ovarian cancer progression. However, the crosstalk between BRCA1 and AGTR1 signaling pathways remains largely unknown. BRCA1 promoter methylation was analyzed by bisulfite sequence using primers focused on the core promoter region. Expression levels of BRCA1 and AGTR1 were assessed by immunohistochemistry and real-time PCR. Regression analysis was used to examine the possible relationship between BRCA1 and AGTR1 protein levels. Knockdown or overexpression of BRCA1 was achieved by using a lentiviral vector in 293 T cells and SKOV3 ovarian carcinoma cells, and primary non-mutated and BRCA1-mutated ovarian cancer cells. BRCA1 dysfunction (BRCA1 mutation or hypermethylated BRCA1 promoter) ovarian cancer showed decreased AGTR1 levels compared to normal tissue. In contrast, AGTR1 expression was increased in non-BRCA1-mutated ovarian cancer. Notably, BRCA1 activation was an effective way to induce AGTR1 expression in primary ovarian cancer cells and a positive correlation exists between BRCA1 and AGTR1 expression in human ovarian cancer specimens. These results indicate that BRCA1 may be a potential trigger involved in the transcriptional regulation of AGTR1 in the development of ovarian cancer.

  18. Analysis of correlations between coronary heart disease and haplotypes of the angiotensin II receptor type 1 (AGTR1) gene.

    Science.gov (United States)

    Duan, L J; Wang, X D

    2016-03-18

    This study aimed to explore correlations between haplotypes of the angiotensin II receptor type 1 (AGTR1) gene and coronary heart disease (CHD). In total, 204 patients with CHD and 206 healthy controls were genotyped using denaturing high-performance liquid chromatography between 2008 and 2014. Five polymorphic loci were found, namely, A-43281G, A-32954G, G-32839A, G-11064A, and A1880G. Likelihood estimates were used to identify haplotypes consisting of the A1166C locus and four of these five loci, then correlations between these haplotypes and CHD were assessed. Eight haplotypes with a frequency greater than 3% in the study population were discerned: ACCAA [odds ratio (OR) = 1.2381, 95% confidence interval (CI) = 0.7726-1.9843]; ACCCA (OR = 1.2604, 95%CI = 0.6104-2.6027); ACTAA (OR = 0.8929, 95%CI = 0.6607-1.2067); ACTAG (OR = 0.9274, 95%CI = 0.5692-1.5110); ATTAA (OR = 1.0347, 95%CI = 0.7505-1.4265); ATTAG (OR = 0.9110, 95%CI = 0.4227-1.9631); GCCAA (OR = 1.1273, 95%CI = 0.7259-1.7506); and GCTAA (OR = 0.7981, 95%CI = 0.4379-1.4546). However, the frequency of these haplotypes did not significantly differ between CHD and the control groups. Thus, no correlation was established between the occurrence of CHD and AGTR1 haplotypes present at frequencies greater than 3%.

  19. Aldosterone breakthrough caused by chronic blockage of angiotensin II type 1 receptors in human adrenocortical cells: Possible involvement of bone morphogenetic protein-6 actions

    OpenAIRE

    Otani, Hiroyuki; Otsuka, Fumio; Inagaki, Kenichi; Suzuki, Jiro; Miyoshi, Tomoko; KANO, YOSHIHIRO; GOTO, Junko; Ogura, Toshio; Makino, Hirofumi

    2008-01-01

    Circulating aldosterone concentrations occasionally increase after initial suppression with angiotensin II (Ang II) converting enzyme inhibitors or Ang II type 1 receptor blockers (ARBs), a phenomenon referred to as aldosterone breakthrough. However, the underlying mechanism causing the aldosterone breakthrough remains unknown. Here we investigated whether aldosterone breakthrough occurs in human adrenocortical H295R cells in vitro. We recently reported that bone morphogenetic protein (BMP)-6...

  20. The angiotensin II type 1 receptor blocker olmesartan preferentially improves nocturnal hypertension and proteinuria in chronic kidney disease

    Science.gov (United States)

    Yanagi, Mai; Tamura, Kouichi; Fujikawa, Tetsuya; Wakui, Hiromichi; Kanaoka, Tomohiko; Ohsawa, Masato; Azushima, Kengo; Maeda, Akinobu; Kobori, Hiroyuki; Umemura, Satoshi

    2013-01-01

    Accumulated evidence suggests that an altered ambulatory blood pressure (BP) profile, particularly elevated nighttime BP, reflects target organ injury and is a better predictor of further cardiorenal risk than the clinic BP or daytime BP in hypertensive patients complicated by chronic kidney disease (CKD). In this study, we examined the beneficial effects of olmesartan, an angiotensin II type 1 receptor blocker (ARB), on ambulatory BP profiles and renal function in hypertensive CKD patients. Forty-six patients were randomly assigned to the olmesartan add-on group (n=23) or the non-ARB group (n=23). At baseline and after the 16-week treatment period, ambulatory BP monitoring was performed and renal function parameter measurements were collected. Although the baseline clinic BP levels and the after-treatment/baseline (A/B) ratios of clinic BP levels were similar in the olmesartan add-on and non-ARB groups, the A/B ratios of ambulatory 24-h and nighttime BP levels in the olmesartan add-on group were significantly lower. Furthermore, the A/B ratios of urinary protein, albumin and type IV collagen excretion in the olmesartan add-on group were significantly lower than those in the non-ARB group (urinary protein excretion, 0.72±0.41 vs. 1.45±1.48, P=0.030; urinary albumin excretion, 0.73±0.37 vs. 1.50±1.37, P 0.005; urinary type IV collagen excretion, 0.87±0.42 vs. 1.48±0.87, P=0.014) despite comparable A/B ratios for the estimated glomerular filtration rate in the two groups. These results indicate that in hypertensive patients with CKD, olmesartan add-on therapy improves the ambulatory BP profile via a preferential reduction in nighttime BP with concomitant renal injury inhibition. PMID:23154587

  1. Angiotensin-converting enzyme and angiotensin II receptor subtype 2 genotypes in type 1 diabetes and severe hypoglycaemia requiring emergency treatment: a case cohort study

    DEFF Research Database (Denmark)

    Pedersen-Bjergaard, Ulrik; Nielsen, Søren L; Akram, Kamran

    2009-01-01

    . METHODS: The case cohort study consisted of 108 cases of type 1 diabetic patients with severe hypoglycaemia requiring medical emergency treatment during a 1-year period and 262 consecutive controls without such events. ACE I/D and AT2R 1675G>A genotype distributions were compared between cases......AIMS: In type 1 diabetes, individual susceptibility to severe hypoglycaemia is likely to be influenced by genetic factors. We have previously reported an association of the deletion (D-) allele of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and the A...... and controls. RESULTS: The proportion of D-allele carriers was higher amongst cases than controls (83 vs. 73%; P=0.032). In contrast, AT2R genotype distribution was similar in cases and controls. In a multiple regression analysis, D-allele carriage remained a significant risk factor for being a case [odds...

  2. A polymorphism in the angiotensin II type 1 receptor gene has different effects on the risk of diabetic nephropathy in men and women

    DEFF Research Database (Denmark)

    Möllsten, Anna; Vionnet, Nathalie; Forsblom, Carol

    2011-01-01

    -control study investigated the association of the rs5186 polymorphism, in the angiotensin II type 1 receptor gene (AGTR1), with diabetic nephropathy. The study included 3561 patients with type 1 diabetes from Denmark, Finland, France and Sweden. Microalbuminuria was defined as albumin excretion rate (AER) ≥20......, there were no significant associations between rs5186 and diabetic nephropathy, OR=0.89 (0.71-1.11), P=0.30. CONCLUSION: We conclude that the AGTR1 gene may be associated with increased risk of diabetic nephropathy in men with type 1 diabetes....

  3. Angiotensin type 1a receptors in the forebrain subfornical organ facilitate leptin-induced weight loss through brown adipose tissue thermogenesis.

    Science.gov (United States)

    Young, Colin N; Morgan, Donald A; Butler, Scott D; Rahmouni, Kamal; Gurley, Susan B; Coffman, Thomas M; Mark, Allyn L; Davisson, Robin L

    2015-04-01

    Elevations in brain angiotensin-II cause increased energy expenditure and a lean phenotype. Interestingly, the metabolic effects of increased brain angiotensin-II mimic the actions of leptin, suggesting an interaction between the two systems. Here we demonstrate that angiotensin-type 1a receptors (AT1aR) in the subfornical organ (SFO), a forebrain structure emerging as an integrative metabolic center, play a key role in the body weight-reducing effects of leptin via brown adipose tissue (BAT) thermogenesis. Cre/LoxP technology coupled with targeted viral delivery to the SFO in a mouse line bearing a conditional allele of the Agtr1a gene was utilized to determine the interaction between leptin and SFO AT1aR in metabolic regulation. Selective deletion of AT1aR in the SFO attenuated leptin-induced weight loss independent of changes in food intake or locomotor activity. This was associated with diminished leptin-induced increases in core body temperature, blunted upregulation of BAT thermogenic markers, and abolishment of leptin-mediated sympathetic activation to BAT. These data identify a novel interaction between angiotensin-II and leptin in the control of BAT thermogenesis and body weight, and highlight a previously unrecognized role for the forebrain SFO in metabolic regulation.

  4. Construction of shRNA Targeted to the Rat AngiotensinType 1 Receptors and Its RNAi in Cytoplasma

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The expression vector of shRNA targeted to the rat angiotensinreceptor gene wasconstructed and the efficacy of siRNAs to modulate the expression of target gene in the in vitro cul-tured mammalian cells was investigated for antihypertensive therapy in spontaneous hypertensive rat(SHR) at post-transcriptional level. The sense and antisense RNA oligonucleotides strands targe-ting angiotensinreceptor mRNA were synthesized individually according to the sequence of therat angiotensinreceptor. For preparation of duplexes, sense- and antisense-stranded oligonucle-otides were mixed and annealed, and the annealed duplexes were cloned into the pGenesil-1 vector..The rat glioma cells were transfected with constructed pGenesil-1-shRNA plasmid and scrambled plasmid. The cultured cells were collected at different phases. RT-PCR and Western blot were performed. The AT1 mRNA and protein levels behaved ultimately same. Compared to control after 48 h, AT1 mRNA levels were decreased to 35.5 %±3.0 %, and the levels reached their lowest point after 72 h (20.7 %±4 % of control). At 24 and 48 h, AT1 protein was reduced to 46.9 %±4.2 %and 36.98 % ± 3.7 % respectively compared to control and a maximum reduction was observed after 72 h of incubation (28. 1% ±4 % compared to controls). Plasmid-based shRNA expression systems targeted against the rat angiotensinreceptor gene were generated successfully. The shRNAs with a 22-nt stem and a short loop were cleaved into small interfering dsRNA (siRNA) by the Dicer. The in vitro transcribed siRNA enables the effective silencing of gene expression to the target mRNA and leads to effective inhibition of translation of proteins and will be lay the foundation of application of gene silencing technology to hypertensive rats.

  5. Improvement of Plasma Biomarkers after Switching Stroke Patients from Other Angiotensin II Type I Receptor Blockers to Olmesartan.

    Science.gov (United States)

    Tada, Yoshiteru; Yagi, Kenji; Uno, Masaaki; Matsushita, Nobuhisa; Kanematsu, Yasuhisa; Kuwayama, Kazuyuki; Shimada, Kenji; Nishi, Kyoko; Hirasawa, Motohiro; Satomi, Junichiro; Kitazato, Keiko T; Kageji, Teruyoshi; Matsuura, Eiji; Nagahiro, Shinji

    2015-07-01

    Managing hypertension is crucial for preventing stroke recurrence. Some stroke patients experience resistant hypertension. In our experimental stroke model, olmesartan increased the expression of angiotensin (Ang) II converting enzyme-2. We hypothesized that switching to olmesartan affects biomarkers and the blood pressure (BP) in stroke patients whose BP is insufficiently controlled by standard doses of Ang II type I receptor blockers (ARBs) other than olmesartan. We recruited 25 patients to study our hypothesis. All had a history of stroke or silent cerebral infarction. We switched them to olmesartan (10-40 mg per day) for 12 weeks and determined their plasma level of Ang-(1-7), peroxiredoxin, oxidized low-density lipoprotein (oxLDL)/β-2-glycoprotein I (β2GPI) complex, adiponectin, high mobility group box 1 (HMGB1), and tumor necrosis factor-α (TNFα) and recorded their BP before and after olmesartan treatment. After switching the patients to olmesartan, their plasma level of Ang-(1-7) as a vasoprotective indicator and adiponectin regulating metabolic syndrome was increased, and peroxiredoxin and the oxLDL/β2GPI complex indicating its antioxidative stress and its proatherogenicity were lower than their baseline. This suggests that olmesartan may be more effective than other ARBs to improve these conditions. Neither HMGB1 nor TNFα reflecting an inflammatory response was affected, suggesting that the anti-inflammatory effects of olmesartan are similar to those of other ARBs. The recommended BP (olmesartan. No adverse events occurred. Switching from other ARBs to olmesartan may be a promising therapeutic option in patients with resistant hypertension. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  6. Actin cytoskeleton-dependent Rab GTPase-regulated angiotensin type I receptor lysosomal degradation studied by fluorescence lifetime imaging microscopy

    Science.gov (United States)

    Li, Hewang; Yu, Peiying; Sun, Yuansheng; Felder, Robin A.; Periasamy, Ammasi; Jose, Pedro A.

    2010-09-01

    The dynamic regulation of the cellular trafficking of human angiotensin (Ang) type 1 receptor (AT1R) is not well understood. Therefore, we investigated the cellular trafficking of AT1R-enhanced green fluorescent protein (EGFP) (AT1R-EGFP) heterologously expressed in HEK293 cells by determining the change in donor lifetime (AT1R-EGFP) in the presence or absence of acceptor(s) using fluorescence lifetime imaging-fluorescence resonance energy transfer (FRET) microscopy. The average lifetime of AT1R-EGFP in our donor-alone samples was ~2.33 ns. The basal state lifetime was shortened slightly in the presence of Rab5 (2.01+/-0.10 ns) or Rab7 (2.11+/-0.11 ns) labeled with Alexa 555, as the acceptor fluorophore. A 5-min Ang II treatment markedly shortened the lifetime of AT1R-EGFP in the presence of Rab5-Alexa 555 (1.78+/-0.31 ns) but was affected minimally in the presence of Rab7-Alexa 555 (2.09+/-0.37 ns). A 30-min Ang II treatment further decreased the AT1R-EGFP lifetime in the presence of both Rab5- and Rab7-Alexa 555. Latrunculin A but not nocodazole pretreatment blocked the ability of Ang II to shorten the AT1R-EGFP lifetime. The occurrence of FRET between AT1R-EGFP (donor) and LAMP1-Alexa 555 (acceptor) with Ang II stimulation was impaired by photobleaching the acceptor. These studies demonstrate that Ang II-induced AT1R lysosomal degradation through its association with LAMP1 is regulated by Rab5/7 via mechanisms that are dependent on intact actin cytoskeletons.

  7. Genetic Association Study of Angiotensin II Receptor Types 1 (A168G) and 2 (T1247G and A5235G) Polymorphisms in Breast Carcinoma among Brazilian Women

    Science.gov (United States)

    Molina Wolgien, Maria del Carmen Garcia; Guerreiro da Silva, Ismael Dale Cotrim; Pinto Nazário, Afonso Celso; Nakaie, Clovis Riuche; Correa-Noronha, Silvana Aparecida Alves; Ribeiro de Noronha, Samuel Marcos; Facina, Gil

    2014-01-01

    Summary Background Many types of cancer are associated with polymorphisms of the renin-angiotensin system. Our aim was to assess possible association between single-nucleotide polymorphisms (SNPs) of the angiotensin II receptor types 1 (A168G), and 2 (T1247G and A5235G) with breast cancer. Patients and Methods 242 participating subjects were genotyped and allocated to case or control groups. Results Genotype distribution (in %) was: for AGTR1 (A168G): AA, AG, GG = 61, 30, 09 for cases, and 69, 25, 06 for controls (p = 0.55); for AGTR2 (T1247G): TT, TG, GG = 84, 12, 04 for cases, and 81, 17, 02 for controls (p = 0.45); for AGTR2 (A5235G): AA, AG, GG = 32, 67, 01 for cases, and 53, 28, 19 for controls (p < 0.0001). Women carrying genotypes AA/AG in the intronic region of angiotensin II type 2 receptor had an 11-fold higher risk of breast cancer than GG carriers. Conclusions Many types of cancer have been associated with polymorphisms of the renin-angiotensin system. For SNP A5235G, the GG genotype seems to be protective against breast cancer. The other 2 SNPs showed no association. However, SNPs T1247G and A5235G were associated with at least 1 clinical variable, with G being a predictor of better outcome. The use of SNPs A5235G and T1247G (the latter to a lesser degree) as genetic markers should be considered. PMID:25177259

  8. Renal angiotensin II type-2 receptors are upregulated and mediate the candesartan-induced natriuresis/diuresis in obese Zucker rats.

    Science.gov (United States)

    Hakam, Amer C; Hussain, Tahir

    2005-02-01

    Recently, there has been a growing interest in studying the role of angiotensin II type-2 (AT(2)) receptor in renal/cardiovascular function in pathological conditions. The present study was designed to determine the functional role of the AT(2) receptors on natriuresis/diuresis and compare the level of the tubular AT(2) receptor expression in obese and lean Zucker rats (12 weeks old). Under anesthesia, candesartan (angiotensin II type 1 [AT(1)]-specific antagonist; 100 microg/kg bolus) produced natriuresis/diuresis to a greater degree in obese than in lean rats. The specific AT(2) antagonist PD123319 (50 microg/kg per minute) after candesartan administration abolished the natriuretic/diuretic effects of candesartan in obese rats but not in lean rats. Infusion of AT(2) receptor agonist, CGP-42112A (1 microg/kg per minute), produced greater increase in sodium and urine excretion over basal in obese than in lean rats. The presence of the AT(2) receptor expression in the brush-border and basolateral membranes was confirmed by Western blotting using specific antibody and antigen-blocking peptide. Densitometric analysis of the bands revealed approximately 1.5- to 2.0-fold increase in the AT(2) receptor proteins in both membranes of obese compared with lean rats. Our results suggest upregulation of the AT(2) receptors, which play a role in mediating the natriuretic/diuretic effects of AT(1) receptor blockers in obese Zucker rats. We speculate that AT(2) receptors, by promoting sodium excretion, may protect obese Zucker rats against blood pressure increase associated with sodium and water retention.

  9. An Angiotensin II Type 1 Receptor Blocker Prevents Renal Injury via Inhibition of the Notch Pathway in Ins2 Akita Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Masaya Koshizaka

    2012-01-01

    Full Text Available Recently, it has been reported that the Notch pathway is involved in the pathogenesis of diabetic nephropathy. In this study, we investigated the activation of the Notch pathway in Ins2 Akita diabetic mouse (Akita mouse and the effects of telmisartan, an angiotensin II type1 receptor blocker, on the Notch pathway. The intracellular domain of Notch1 (ICN1 is proteolytically cleaved from the cell plasma membrane in the course of Notch activation. The expression of ICN1 and its ligand, Jagged1, were increased in the glomeruli of Akita mice, especially in the podocytes. Administration of telmisartan significantly ameliorated the expression of ICN1 and Jagged1. Telmisartan inhibited the angiotensin II-induced increased expression of transforming growth factor β and vascular endothelial growth factor A which could directly activate the Notch signaling pathway in cultured podocytes. Our results indicate that the telmisartan prevents diabetic nephropathy through the inhibition of the Notch pathway.

  10. An angiotensin II type 1 receptor blocker prevents renal injury via inhibition of the Notch pathway in Ins2 Akita diabetic mice.

    Science.gov (United States)

    Koshizaka, Masaya; Takemoto, Minoru; Sato, Seiya; Tokuyama, Hirotake; Fujimoto, Masaki; Okabe, Emiko; Ishibashi, Ryoichi; Ishikawa, Takahiro; Tsurutani, Yuya; Onishi, Shunichiro; Mezawa, Morito; He, Peng; Honjo, Satoshi; Ueda, Shiro; Saito, Yasushi; Yokote, Koutaro

    2012-01-01

    Recently, it has been reported that the Notch pathway is involved in the pathogenesis of diabetic nephropathy. In this study, we investigated the activation of the Notch pathway in Ins2 Akita diabetic mouse (Akita mouse) and the effects of telmisartan, an angiotensin II type1 receptor blocker, on the Notch pathway. The intracellular domain of Notch1 (ICN1) is proteolytically cleaved from the cell plasma membrane in the course of Notch activation. The expression of ICN1 and its ligand, Jagged1, were increased in the glomeruli of Akita mice, especially in the podocytes. Administration of telmisartan significantly ameliorated the expression of ICN1 and Jagged1. Telmisartan inhibited the angiotensin II-induced increased expression of transforming growth factor β and vascular endothelial growth factor A which could directly activate the Notch signaling pathway in cultured podocytes. Our results indicate that the telmisartan prevents diabetic nephropathy through the inhibition of the Notch pathway.

  11. Left ventricular hypertrophy and angiotensin II receptor blocking agents.

    Science.gov (United States)

    Yasunari, K; Maeda, K; Nakamura, M; Watanabe, T; Yoshikawa, J; Hirohashi, K

    2005-01-01

    Angiotensin II plays a significant role in cell growth and proliferation in model systems and in humans. Numerous studies have shown that left ventricular hypertrophy (LVH) increases the risk of coronary heart disease, congestive heart failure, stroke or transient ischemic attack; all-cause deaths, and sudden death. The use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) has provided beneficial effects on LVH regression and on cardiac remodeling in the presence of hypertension and heart failure. The new class of ARBs appears to provide cardioprotective effects that are similar to those of the ACE inhibitors. Most of the beneficial effects provided by these agents appear to be related to a more complete blockade of the angiotensin II type 1 (AT1) receptor. However, costimulation of the angiotensin II type 2 (AT2) receptor appears to increase nitric oxide and thus causes some bradykinin-like effects. Evidence for the role of angiotensin II in promoting LVH as well as abnormal regulation of the angiotensin II signal transduction pathways in model systems and in humans has been reviewed. Secondly, the mechanisms for the beneficial effects of angiotensin II receptor blockers studied in model systems and in humans, including possible involvement in the formation of reactive oxygen species by mononuclear cells, are presented. Finally, results from large-scale interventions such as the Losartan Intervention For Endpoint reduction (LIFE) study, as well as an overview of the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial involving the use of ARB in high-risk patients, are presented.

  12. Cardiac overexpression of constitutively active Galpha q causes angiotensin II type1 receptor activation, leading to progressive heart failure and ventricular arrhythmias in transgenic mice.

    Directory of Open Access Journals (Sweden)

    Naoko Matsushita

    Full Text Available Transgenic mice with transient cardiac expression of constitutively active Galpha q (Gαq-TG exhibt progressive heart failure and ventricular arrhythmias after the initiating stimulus of transfected constitutively active Gαq becomes undetectable. However, the mechanisms are still unknown. We examined the effects of chronic administration of olmesartan on heart failure and ventricular arrhythmia in Gαq-TG mice.Olmesartan (1 mg/kg/day or vehicle was chronically administered to Gαq-TG from 6 to 32 weeks of age, and all experiments were performed in mice at the age of 32 weeks. Chronic olmesartan administration prevented the severe reduction of left ventricular fractional shortening, and inhibited ventricular interstitial fibrosis and ventricular myocyte hypertrophy in Gαq-TG. Electrocardiogram demonstrated that premature ventricular contraction (PVC was frequently (more than 20 beats/min observed in 9 of 10 vehicle-treated Gαq-TG but in none of 10 olmesartan-treated Gαq-TG. The collected QT interval and monophasic action potential duration in the left ventricle were significantly shorter in olmesartan-treated Gαq-TG than in vehicle-treated Gαq-TG. CTGF, collagen type 1, ANP, BNP, and β-MHC gene expression was increased and olmesartan significantly decreased the expression of these genes in Gαq-TG mouse ventricles. The expression of canonical transient receptor potential (TRPC 3 and 6 channel and angiotensin converting enzyme (ACE proteins but not angiotensin II type 1 (AT1 receptor was increased in Gαq-TG ventricles compared with NTG mouse ventricles. Olmesartan significantly decreased TRPC6 and tended to decrease ACE expressions in Gαq-TG. Moreover, it increased AT1 receptor in Gαq-TG.These findings suggest that angiotensin II type 1 receptor activation plays an important role in the development of heart failure and ventricular arrhythmia in Gαq-TG mouse model of heart failure.

  13. Comparing the effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on renal function decline in diabetes

    NARCIS (Netherlands)

    Huang, Yunyu; Haaijer-Ruskamp, Flora M.; Voorham, Jaco

    2016-01-01

    Aim: To compare effectiveness of angiotensin-converting enzyme inhibitors (ACEis)/angiotensin receptor blockers (ARBs) for protecting Type 2 diabetes mellitus (DM2) patients from renal function decline in a real-world setting. Methods: Retrospective cohort study of new ACEi/ARB users in 2007-2012 in

  14. Angiotensin II receptor mRNA expression and vasoconstriction in human coronary arteries

    DEFF Research Database (Denmark)

    Wackenfors, Angelica; Pantev, Emil; Emilson, Malin;

    2004-01-01

    Angiotensin II is a potent vasoconstrictor that is implicated in the pathogenesis of hypertension, heart failure and atherosclerosis. In the present study, angiotensin II receptor mRNA expression levels were quantified by real-time polymerase chain reaction and the vasocontractile responses...... to angiotensin II were characterised by in vitro pharmacology in endothelium-denuded human coronary arteries. Angiotensin II type 1 (AT(1)) and type 2 (AT(2)) receptor mRNA expression levels were significantly down-regulated in arteries from patients with heart failure as compared to controls. The angiotensin II...

  15. Modulation of the delayed rectifier K+ current in neurons by an angiotensin II type 2 receptor fragment.

    Science.gov (United States)

    Kang, J; Richards, E M; Posner, P; Sumners, C

    1995-01-01

    Angiotensin II (ANG II) stimulates the delayed rectifier K+ current (IK) in neurons cultured from rat hypothalamus and brain stem via AT2 receptors, and this effect involves activation of a Gi protein and protein phosphatase 2A (PP2A). However, there was no evidence that the AT2 receptor involved in this response was the same as the recently cloned AT2 receptor. In the present study, intracellular injection of a 22-amino acid peptide (PEP-22) corresponding to the putative third intracellular loop of the cloned AT2 receptor elicited an increase in IK in cultured neurons that was similar to the effect produced by ANG II. Furthermore, this effect of PEP-22 was abolished by pertussis toxin (200 ng/ml, 24 h) pretreatment and also by superfusion of the PP2A inhibitor okadaic acid (10 nM), suggesting the involvement of Gi protein and PP2A, respectively. Intracellular injection of a random peptide or normal pipette solution did not affect neuronal IK. This is direct evidence to link the cloned AT2 receptor to a defined response elicited by ANG II.

  16. Selective C1 Lesioning Slightly Decreases Angiotensin II type I Receptor Expression in the Rat Rostral Ventrolateral Medulla (RVLM)

    Science.gov (United States)

    Bourassa, Erick A.; Stedenfeld, Kristen A.; Sved, Alan F.; Speth, Robert C.

    2015-01-01

    Cardiovascular homeostasis is regulated in large part by the rostral ventrolateral medulla (RVLM) in mammals. Projections from the RVLM to the intermediolateral column of the thoracolumbar spinal cord innervate preganglionic neurons of the sympathetic nervous system causing elevation of blood pressure and heart rate. A large proportion, but not all, of the neurons in the RVLM contain the enzymes necessary for the production of epinephrine and are identified as the C1 cell group. Angiotensin II (Ang II) activates the RVLM acting upon AT1 receptors. To assess the proportion of AT1 receptors that are located on C1 neurons in the rat RVLM this study employed an antibody to dopamine-beta-hydroxylase conjugated to saporin, to selectively destroy C1 neurons in the RVLM. Expression of tyrosine hydroxylase immunoreactive neurons in the RVLM was reduced by 57 % in the toxin injected RVLM compared to the contralateral RVLM. In contrast, densitometric analysis of autoradiographic images of 125I-sarcosine1, isoleucine8 Ang II binding to AT1 receptors of the injected side RVLM revealed a small (10%) reduction in AT1 receptor expression compared to the contralateral RVLM. These results suggest that the majority of AT1 receptors in the rat RVLM are located on non-C1 neurons or glia. PMID:26138553

  17. Angiotensin type 2 receptors

    DEFF Research Database (Denmark)

    Sumners, Colin; de Kloet, Annette D; Krause, Eric G;

    2015-01-01

    R blockade. Despite a lack of effect on blood pressure, AT2R stimulation still protects from hypertensive end-organ damage. Current data and evidence therefore suggest that AT2R agonists will not be suitable as future anti-hypertensive drugs, but that they may well be useful for end-organ protection...

  18. The impact of renin-angiotensin system, angiotensin І converting enzyme (insertion/deletion), and angiotensin ІІ type 1 receptor (A1166C) polymorphisms on breast cancer survival in Iran.

    Science.gov (United States)

    Namazi, Soha; Daneshian, Arghavan; Mohammadianpanah, Mohammad; Jafari, Peyman; Ardeshir-Rouhani-Fard, Shirin; Nasirabadi, Shiva

    2013-12-10

    Several proteins of renin-angiotensin system (RAS) have been implicated in the process of growth promotion or inhibition of breast tissue and cancer cells. This study aimed to investigate the association between angiotensin I converting enzyme (ACE) insertion/deletion (I/D) and angiotensin receptor-1 (AGTR1) A1166C polymorphisms and survival of 110 women with breast cancer. The I/D and A1166C polymorphisms were evaluated by using Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) in 110 breast cancer patients who had been treated between 2007 and 2009. Genomic DNA was extracted from a Formalin-Fixed Paraffin-Embedded (FFPE) tissue of breast cancer sample blocks. All the potential clinical and pathological prognostic variables were analyzed to establish the impact of I/D and A1166C polymorphisms on disease-free and overall survival rates. Disease-free and overall survival rates were the primary endpoints of the study. The ACE (I/D) polymorphism was associated with 3-year disease-free survival. Disease-free survival in DD carriers was significantly increased compared to ID plus II carriers (HR=4.75; 95% CI, 1.39-16.24; p=0.013). No significant association was found between AGTR1 (A1166C) and 3-year disease-free survival (p=0.233). Also, the ACE (I/D) and AGTR1 (A1166C) polymorphisms were not associated with breast cancer overall survival. The ACE (I/D) polymorphism was associated with 3-year disease-free survival of the women with breast cancer. Besides, disease-free survival in DD carriers was significantly increased compared to ID plus II carriers. © 2013 Elsevier B.V. All rights reserved.

  19. Neuroprotective effect of an angiotensin receptor type 2 agonist following cerebral ischemia in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Lee Seyoung

    2012-08-01

    Full Text Available Abstract Background Intracerebral administration of the angiotensin II type 2 receptor (AT2R agonist, CGP42112, is neuroprotective in a rat model of ischemic stroke. To explore further its possible cellular target(s and therapeutic utility, we firstly examined whether CGP42112 may exert direct protective effects on primary neurons following glucose deprivation in vitro. Secondly, we tested whether CGP42112 is effective when administered systemically in a mouse model of cerebral ischemia. Methods Primary cortical neurons were cultured from E17 C57Bl6 mouse embryos for 9 d, exposed to glucose deprivation for 24 h alone or with drug treatments, and percent cell survival assessed using trypan blue exclusion. Ischemic stroke was induced in adult male C57Bl6 mice by middle cerebral artery occlusion for 30 min, followed by reperfusion for 23.5 h. Neurological assessment was performed and then mice were euthanized and infarct and edema volume were analysed. Results During glucose deprivation, CGP42112 (1x10-8 M and 1x10-7 M reduced cell death by ~30%, an effect that was prevented by the AT2R antagonist, PD123319 (1x10-6 M. Neuroprotection by CGP42112 was lost at a higher concentration (1x10-6 M but was unmasked by co-application with the AT1R antagonist, candesartan (1x10-7 M. By contrast, Compound 21 (1x10-8 M to 1x10-6 M, a second AT2R agonist, had no effect on neuronal survival. Mice treated with CGP42112 (1 mg/kg i.p. after cerebral ischemia had improved functional outcomes over vehicle-treated mice as well as reduced total and cortical infarct volumes. Conclusions These results indicate that CGP42112 can directly protect neurons from ischemia-like injury in vitro via activation of AT2Rs, an effect opposed by AT1R activation at high concentrations. Furthermore, systemic administration of CGP42112 can reduce functional deficits and infarct volume following cerebral ischemia in vivo.

  20. The angiotensin II type 1 receptor blocker losartan attenuates bioprosthetic valve leaflet calcification in a rabbit intravascular implant model.

    Science.gov (United States)

    Shin, Hong Ju; Kim, Dae-Hyun; Park, Han Ki; Park, Young Hwan

    2016-12-01

    There is evidence that angiotensin II type I receptor blocker (ARB) could reduce structural valve deterioration. However, the anticalcification effect on the bioprosthetic heart valve (BHV) has not been investigated. Thus, we investigated the effects of losartan (an ARB) on calcification of implanted bovine pericardial tissue in a rabbit intravascular implant model. A total of 16 male New Zealand White rabbits (20 weeks old, 2.98-3.34 kg) were used in this study. Commercially available BHV leaflet of bovine pericardium was trimmed to the shape of a 3-mm triangle and implanted to both external jugular veins of the rabbit. The ARB group (n = 8) was given 25 mg/kg of powdered losartan daily until 6 weeks after surgery by direct administration in the buccal pouch of the animals. The control group (n = 8) was given 5 ml of normal saline by the same method. After 6 weeks, quantitative calcium determination, histological evaluation and western blot analysis of interleukin-6 (IL-6), osteopontin and bone morphogenetic protein 2 (BMP-2) were performed to investigate the mechanisms of the anticalcification effect of losartan. No deaths or complications such as infection or haematoma were recorded during the experiment. All animals were euthanized on the planned date. The calcium measurement level in the ARB group (2.28 ± 0.65 mg/g) was significantly lower than that in the control group (3.68 ± 1.00 mg/g) (P = 0.0092). Immunohistochemistry analyses revealed that BMP-2-positive reactions were significantly attenuated in the ARB group. Western blot analysis showed that losartan suppressed the expression of IL-6, osteopontin and BMP-2. Our results indicate that losartan significantly attenuates postimplant degenerative calcification of a bovine pericardial bioprosthesis in a rabbit intravascular implant model. Further studies are required to assess the effects of ARBs on BHV tissue in orthotopic implantations using a large animal model. © The Author 2016. Published by Oxford

  1. Murine double nullizygotes of the angiotensin type 1A and 1B receptor genes duplicate severe abnormal phenotypes of angiotensinogen nullizygotes.

    OpenAIRE

    Tsuchida, S.; Matsusaka, T; Chen, X; Okubo, S.; Niimura, F; Nishimura, H.; Fogo, A.; Utsunomiya, H.; Inagami, T; Ichikawa, I

    1998-01-01

    Rodents are the unique species carrying duplicated angiotensin (Ang) type 1 (AT1) receptor genes, Agtr1a and Agtr1b. After separately generating Agtr1a and Agtr1b null mutant mice by gene targeting, we produced double mutant mice homozygous for both Agtr1a and Agtr1b null mutation (Agtr1a-/-; Agtr1b-/-) by mating the single gene mutants. Agtr1a-/-, Agtr1b-/- mice are characterized by normal in utero survival but decreased ex utero survival rate. After birth they are characterized by low body ...

  2. Angiotensin type 2-receptor (AT2R) activation induces hypotension in apolipoprotein E-deficient mice by activating peroxisome proliferator-activated receptor

    Science.gov (United States)

    Li, Ming; Tejada, Thor; Lambert, Jonathan P; Nicholson, Chad K; Yahiro, Eiji; Ambai, Vats T; Ali, Syeda F; Bradley, Eddie W; Graham, Robert M; Dell’Italia, Louis J; Calvert, John W; Naqvi, Nawazish

    2016-01-01

    Angiotensin II (Ang II) modulates blood pressure and atherosclerosis development through its vascular type-1 (AT1R) and type-2 (AT2R) receptors, which have opposing effects. AT2R activation produces hypotension, and is anti-atherogenic. Targeted overexpression of AT2Rs in vascular smooth muscle cells (VSMCs) indicates that these effects are due to increased nitric oxide (NO) generation. However, the role of endogenous VSMC AT2Rs in these events is unknown. Effect of 7-day low-dose Ang II-infusion (12 µg/kg/hr) on blood pressure was tested in 9-week-old apoE(-/-) mice fed a low or high cholesterol diet (LCD or HCD, respectively). Cardiac output was measured by echocardiography. Immunohistochemistry was performed to localize and quantify AT2Rs and p-Ser1177-endothelial nitric oxide synthase (eNOS) levels in the aortic arch. PD123319 and GW-9662 were used to selectively block the AT2R and peroxisome proliferator-activated receptor-γ (PPAR-γ), respectively. Ang II infusion decreased blood pressure by 12 mmHg (P LCD/apoE(-/-) mice without altering cardiac output; a response blocked by PD123319. Although, AT2R stimulation neither activated eNOS (p-Ser1177-eNOS) nor changed plasma NO metabolites, it caused an ~6-fold increase in VSMC PPAR-γ levels (P < 0.001) and the AT2R-mediated hypotension was abolished by GW-9662. AT2R-mediated hypotension was also inhibited by HCD, which selectively decreased VSMC AT2R expression by ~6-fold (P < 0.01). These findings suggest a novel pathway for the Ang II/AT2R-mediated hypotensive response that involves PPAR-γ, and is down regulated by a HCD. PMID:27679746

  3. Tumor necrosis factor-α inhibits angiotensin II receptor type 1 expression in dorsal root ganglion neurons via β-catenin signaling.

    Science.gov (United States)

    Yang, Y; Wu, H; Yan, J-Q; Song, Z-B; Guo, Q-L

    2013-09-17

    Both tumor necrosis factor (TNF)-α and the angiotensin (Ang) II/angiotensin II receptor type 1 (AT1) axis play important roles in neuropathic pain and nociception. In the present study, we explored the interaction between the two systems by examining the mutual effects between TNF-α and the Ang II/AT1 receptor axis in dorsal root ganglion (DRG) neurons. Rat DRG neurons were treated with TNF-α in different concentrations for different lengths of time in the presence or absence of transcription inhibitor actinomycin D, TNF receptor 1 (TNFR1) inhibitor SPD304, β-catenin signaling inhibitor CCT031374, or different kinase inhibitors. TNF-α decreased the AT1 receptor mRNA level as well as the AT1a receptor promoter activity in a dose-dependent manner within 30 h, which led to dose-dependent inhibition of Ang II-binding AT1 receptor level on the cell membrane. Actinomycin D (1 mg/ml), SPD304 (50 μM), p38 mitogen-activated protein kinase (MAPK) inhibitor PD169316 (25 μM), and CCT031374 (50 μM) completely abolished the inhibitory effect of TNF-α on AT1 receptor expression. TNF-α dose-dependently increased soluble β-catenin and phosphorylated GSK-3β levels, which was blocked by SPD304 and PD169316. In DRG neurons treated with AT2 receptor agonist CGP421140, or Ang II with or without AT1 receptor antagonist losartan or AT2 receptor antagonist PD123319 for 30 h, we found that Ang II and Ang II+PD123319 significantly decreased TNF-α expression, whereas CPG421140 and Ang II+losartan increased TNF-α expression. In conclusion, we demonstrate that TNF-α inhibits AT1 receptor expression at the transcription level via TNFR1 in rat DRG neurons by increasing the soluble β-catenin level through the p38 MAPK/GSK-3β pathway. In addition, Ang II appears to inhibit and induce TNF-α expression via the AT1 receptor and the AT2 receptor in DRG neurons, respectively. This is the first evidence of crosstalk between TNF-α and the Ang II/AT receptor axis in DRG neurons.

  4. Genetic polymorphisms of angiotensin-2 type 1 receptor and angiotensinogen and risk of renal dysfunction and coronary heart disease in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Hu Frank B

    2009-03-01

    Full Text Available Abstract Background Increased activation of the renin-angiotensin system (RAS may be important in promoting coronary heart disease (CHD and renal dysfunction, but limited data are available on associations between angiotensin type 1 receptor (AGT1R and angiotensinogen (AGT genotypes in type 2 diabetes. Methods Study participants were diabetics from the Health Professionals Follow-Up Study (HPFS and the Nurses' Health Study (NHS. We analyzed single nucleotide polymorphisms (SNPs associated with cardiovascular pathophysiology (including AGT1R T573C, AGT1R A1166C, and AGT M235T and presence of renal dysfunction (eGFR2 or history of CHD. Results The AGT1R 1166 C-allele was associated with eGFR2 (multivariable OR 1.63 [1.01, 2.65] in the HPFS men (n = 733 and in the combined dataset (n = 1566 (OR 1.42 [1.02, 1.98]. The AGT1R 1166 C-allele was also associated with CHD in men (OR 1.57 [1.10, 2.24]. In NHS women (n = 833, AGT 235T-allele was associated with CHD (OR 1.72 [1.20, 2.47]. Removal of hypertension from the fully adjusted models did not influence results, suggesting that the associations may not be mediated by hypertension. There were significant interactions between sex and AGT1R 1166 C-allele (p = 0.008 and AGT M235T (p = 0.03 in models for CHD. No significant associations were seen between AGT1R T573 C-allele and renal dysfunction or CHD. Conclusion Polymorphisms in AGT1R and AGT genes are associated with renal dysfunction and CHD in type 2 diabetes and further support the important role of the RAS in these complications. Sex may modify associations between AGT1R 1166 C-allele and AGT 235T and CHD in type 2 diabetes.

  5. Antihypertensive drugs and erectile dysfunction as seen in spontaneous reports, with focus on angiotensin II type 1 receptor blockers

    Science.gov (United States)

    Ekman, Elisabet; Hägg, Staffan; Sundström, Anders; Werkström, Viktoria

    2010-01-01

    Aim: To describe spontaneously reported cases of erectile dysfunction (ED) in association with angiotensin II type I blockers (ARB) and other antihypertensive drugs. Subjects and methods: All spontaneously reported cases of ED submitted to the Swedish Medical Products Agency (MPA) between 1990 and 2006, where at least one antihypertensive drug was the suspected agent, were scrutinized. Patient demographics, drug treatment and adverse reactions were recorded. Using the Bayesian Confidence Propagation Neural Network (BCPNN) method, the information component (IC) was calculated. Results: Among a total of 225 reports of ED, 59 involved antihypertensive drugs including ARB (9 cases) as suspected agents. A positive IC value was found indicating that ED was reported more often in association with antihypertensive drugs classes, except for angiotensin-converting enzyme inhibitors, compared with all other drugs in the database. Positive dechallenge was reported in 43 cases (72%). Discussion: All classes of major antihypertensive drugs including ARB were implicated as suspected agents in cases of ED. Few risk factors were identified. The relatively high reporting of ED in association with ARB is in contrast with previous studies, suggesting that ARB have neither a positive nor any effect on ED. This discrepancy suggests that further studies are warrnted on this potential adverse reaction to ARB. PMID:21701615

  6. Assignment of the human angiotensin II type 2 receptor gene (AGTR2) to chromosome Xq22-q23 by fluorescence in situ hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Chassagne, C.; Meloche, S. [Hotel-Dieu de Montreal, Quebec (Canada); Beatty, B.G. [Hospital for Sick Children, Toronto, Ontario (Canada)

    1995-01-20

    Angiotensin II (AII), the biologically active effector of the renin-angiotensin system, is a major regulator of blood pressure and electrolyte balance and a growth factor for diverse cell types. AII exerts its physiological effects by interacting with two pharmacologically distinct subtypes of receptors, designated AT{sub 1}, and AT{sub 2}. Most of the known responses to AII are mediated by the AT{sub 1} subtype, whereas the function of the AT{sub 2} receptor remains largely unknown. AT{sub 2} receptor expression is abundant in particular tissues such as adrenal medulla, specific brain regions, uterine myometrium, and ovarian granuloma cells. This specific localization in adult coupled to the demonstration that some actions of AII such as secretion of luteinizing hormone and prolactine, dilation of brain arterioles, or drinking response in rats can be inhibited in vitro by an AT{sub 2} receptor antagonist suggests that the AT{sub 2} subtype may play a role in neuronal and reproductive function. In addition, a growing amount of evidence indicates that the AT{sub 2} receptor may play a most important role in processes involving cellular growth and differentiation. It is abundantly and widely expressed in the mesenchymal tissues of the developing fetus and in the immature brain and is up-regulated in the heart and in vascular smooth muscle cells in the first days following birth. Moreover, AT{sub 2} receptor expression is enhanced in the adult in wound healing, in the neointima of injured vessels, and in pheochromocytoma. 12 refs., 1 fig.

  7. Genetic variation in angiotensin II type 2 receptor gene influences extent of left ventricular hypertrophy in hypertrophic cardiomyopathy independent of blood pressure.

    Science.gov (United States)

    Carstens, Nadia; van der Merwe, Lize; Revera, Miriam; Heradien, Marshall; Goosen, Althea; Brink, Paul A; Moolman-Smook, Johanna C

    2011-09-01

    Hypertrophic cardiomyopathy (HCM), an inherited primary cardiac disorder mostly caused by defective sarcomeric proteins, serves as a model to investigate left ventricular hypertrophy (LVH). HCM manifests extreme variability in the degree and distribution of LVH, even in patients with the same causal mutation. Genes coding for renin-angiotensin-aldosterone system components have been studied as hypertrophy modifiers in HCM, with emphasis on the angiotensin (Ang) II type 1 receptor (AT(1)R). However, Ang II binding to Ang II type 2 receptors (AT(2)R) also has hypertrophy-modulating effects. We investigated the effect of the functional +1675 G/A polymorphism (rs1403543) and additional single nucleotide polymorphisms in the 3' untranslated region of the AT(2)R gene (AGTR2) on a heritable composite hypertrophy score in an HCM family cohort in which HCM founder mutations segregate. We find significant association between rs1403543 and hypertrophy, with each A allele decreasing the average wall thickness by ~0.5 mm, independent of the effects of the primary HCM causal mutation, blood pressure and other hypertrophy covariates (p = 0.020). This study therefore confirms a hypertrophy-modulating effect for AT(2)R also in HCM and implies that +1675 G/A could potentially be used in a panel of markers that profile a genetic predisposition to LVH in HCM.

  8. Renoprotective effect of renal liver-type fatty acid binding protein and angiotensin II type 1a receptor loss in renal injury caused by RAS activation.

    Science.gov (United States)

    Ichikawa, Daisuke; Kamijo-Ikemori, Atsuko; Sugaya, Takeshi; Shibagaki, Yugo; Yasuda, Takashi; Katayama, Kimie; Hoshino, Seiko; Igarashi-Migitaka, Junko; Hirata, Kazuaki; Kimura, Kenjiro

    2014-03-15

    The aim of this study was to assess the renoprotective effect of renal human liver-type fatty acid binding protein (hL-FABP) and angiotensin II (ANG II) type 1A receptor (AT1a) loss in renal injury caused by renin-angiotensin system (RAS) activation. We established hL-FABP chromosomal transgenic mice (L-FABP(+/-)AT1a(+/+)), crossed the L-FABP(+/-)AT1a(+/+) with AT1a knockdown homo mice (L-FABP(-/-)AT1a(-/-)), and generated L-FABP(+/-)AT1a hetero mice (L-FABP(+/-)AT1a(+/-)). After the back-cross of these cubs, L-FABP(+/-)AT1a(-/-) were obtained. To activate the renal RAS, wild-type mice (L-FABP(-/-)AT1a(+/+)), L-FABP(+/-)AT1a(+/+), L-FABP(-/-)AT1a(+/-), L-FABP(+/-)AT1a(+/-), L-FABP(-/-)AT1a(-/-), and L-FABP(+/-)AT1a(-/-) were administered high-dose systemic ANG II infusion plus a high-salt diet for 28 days. In the L-FABP(-/-)AT1a(+/+), RAS activation (L-FABP(-/-)AT1a(+/+)RAS) caused hypertension and tubulointerstitial damage. In the L-FABP(+/-)AT1a(+/+)RAS, tubulointerstitial damage was significantly attenuated compared with L-FABP(-/-)AT1a(+/+)RAS. In the AT1a partial knockout (AT1a(+/-)) or complete knockout (AT1a(-/-)) mice, reduction of AT1a expression led to a significantly lower degree of renal injury compared with L-FABP(-/-)AT1a(+/+)RAS or L-FABP(+/-)AT1a(+/+)RAS mice. Renal injury in L-FABP(+/-)AT1a(+/-)RAS mice was significantly attenuated compared with L-FABP(-/-)AT1a(+/-)RAS mice. In both L-FABP(-/-)AT1a(-/-)RAS and L-FABP(+/-)AT1a(-/-)RAS mice, renal damage was rarely found. The degrees of renal hL-FABP expression and urinary hL-FABP levels increased by RAS activation and gradually decreased along with reduction of AT1a expression levels. In conclusion, in this mouse model, renal hL-FABP expression and a decrease in AT1a expression attenuated tubulointerstitial damage due to RAS activation.

  9. Angiotensin II, a neuropeptide at the frontier between endocrinology and neuroscience: Is there a link between the angiotensin II type 2 receptor (AT2R and Alzheimer’s disease?

    Directory of Open Access Journals (Sweden)

    Nicole eGallo-Payet

    2011-08-01

    Full Text Available Amyloid-β peptide deposition, abnormal hyperphosphorylation of tau, as well as inflammation and vascular damage, are associated with the development of Alzheimer’s disease. Angiotensin II (Ang II is a peripheral hormone, as well as a neuropeptide, which binds two major receptors, namely the Ang II type-1 receptor (AT1R and the type-2 receptor (AT2R. Activation of the AT2R counteracts most of the AT1R-mediated actions, promoting vasodilation, decreasing the expression of pro-inflammatory cytokines, both in the brain and in the cardiovascular system. There is evidence that treatment with AT1R blockers (ARBs attenuates learning and memory deficits. Studies suggest that the therapeutic effects of ARBs may reflect this unopposed activation of the AT2R in addition to the inhibition of the AT1R. Within the context of Alzheimer’s disease (AD, modulation of AT2R signaling could improve cognitive performance not only through its action on blood flow/brain microcirculation but also through more specific effects on neurons. This review summarizes the current state of knowledge and potential therapeutic relevance of central actions of this enigmatic receptor. In particular, we highlight the possibility that selective AT2R activation by nonpeptide and highly selective agonists, acting on neuronal plasticity, could represent new pharmacological tools that may help improve impaired cognitive performance in Alzheimer’s disease and other neurological cognitive disorders.

  10. Differential extracellular signal-regulated kinases 1 and 2 activation by the angiotensin type 1 receptor supports distinct phenotypes of cardiac myocytes

    DEFF Research Database (Denmark)

    Aplin, Mark; Christensen, Gitte Lund; Schneider, Mikael;

    2007-01-01

    The angiotensin II (AngII) type 1 receptor (AT(1)R) is a seven-transmembrane receptor well established to activate extracellular signal-regulated kinases 1 and 2 (ERK1/2) by discrete G protein-dependent and beta-arrestin2-dependent pathways. The biological importance of this, however, remains...... that phosphorylates p90 Ribosomal S6 Kinase, a ubiquitous and versatile mediator of ERK1/2 signal transduction. Moreover, the beta-arrestin2-dependent ERK1/2 signal supports intact proliferation of cardiac myocytes. In contrast to G(q)-activated ERK1/2, and in keeping with its failure to translocate to the nucleus......, the beta-arrestin2-scaffolded pool of ERK1/2 does not phosphorylate the transcription factor Elk-1, induces no increased transcription of the immediate-early gene c-Fos, and does not entail myocyte hypertrophy. These results clearly demonstrate the biological significance of differential signalling...

  11. Leveraging NMR and X-ray Data of the Free Ligands to Build Better Drugs Targeting Angiotensin II Type 1 G-Protein Coupled Receptor.

    Science.gov (United States)

    Kellici, Tahsin F; Ntountaniotis, Dimitrios; Kritsi, Eftichia; Zervou, Maria; Zoumpoulakis, Panagiotis; Potamitis, Constantinos; Durdagi, Serdar; Salmas, Ramin Ekhteiari; Ergun, Gizem; Gokdemir, Ebru; Halabalaki, Maria; Gerothanassis, Ioannis P; Liapakis, George; Tzakos, Andreas; Mavromoustakos, Thomas

    2016-01-01

    The angiotensin II type 1 receptor (AT1R) has been recently crystallized. A new era has emerged for the structure-based rational drug design and the synthesis of novel AT1R antagonists. In this critical review, the X-ray crystallographic data of commercially available AT1R antagonists in free form are analyzed and compared with the conformational analysis results obtained using a combination of NMR spectroscopy and Molecular Modeling. The same AT1R antagonists are docked and compared in terms of their interactions in their binding site using homology models and the crystallized AT1R receptor. Various aspects derived from these comparisons regarding rational drug design are outlined.

  12. Comparative effect of angiotensin II type I receptor blockers and calcium channel blockers on laboratory parameters in hypertensive patients with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Nishida Yayoi

    2012-05-01

    Full Text Available Abstract Background Both angiotensin II type I receptor blockers (ARBs and calcium channel blockers (CCBs are widely used antihypertensive drugs. Many clinical studies have demonstrated and compared the organ-protection effects and adverse events of these drugs. However, few large-scale studies have focused on the effect of these drugs as monotherapy on laboratory parameters. We evaluated and compared the effects of ARB and CCB monotherapy on clinical laboratory parameters in patients with concomitant hypertension and type 2 diabetes mellitus. Methods We used data from the Clinical Data Warehouse of Nihon University School of Medicine obtained between Nov 1, 2004 and July 31, 2011, to identify cohorts of new ARB users (n = 601 and propensity-score matched new CCB users (n = 601, with concomitant mild to moderate hypertension and type 2 diabetes mellitus. We used a multivariate-adjusted regression model to adjust for differences between ARB and CCB users, and compared laboratory parameters including serum levels of triglyceride (TG, total cholesterol (TC, non-fasting blood glucose, hemoglobin A1c (HbA1c, sodium, potassium, creatinine, alanine aminotransferase (ALT, aspartate aminotransferase (AST, gamma-glutamyltransferase (GGT, hemoglobin and hematocrit, and white blood cell (WBC, red blood cell (RBC and platelet (PLT counts up to 12 months after the start of ARB or CCB monotherapy. Results We found a significant reduction of serum TC, HbA1c, hemoglobin and hematocrit and RBC count and a significant increase of serum potassium in ARB users, and a reduction of serum TC and hemoglobin in CCB users, from the baseline period to the exposure period. The reductions of RBC count, hemoglobin and hematocrit in ARB users were significantly greater than those in CCB users. The increase of serum potassium in ARB users was significantly greater than that in CCB users. Conclusions Our study suggested that hematological adverse effects and

  13. Calcium channel blocker enhances beneficial effects of an angiotensin II AT1 receptor blocker against cerebrovascular-renal injury in type 2 diabetic mice.

    Directory of Open Access Journals (Sweden)

    Kazi Rafiq

    Full Text Available Recent clinical trials have demonstrated that combination therapy with renin-angiotensin system inhibitors plus calcium channel blockers (CCBs elicits beneficial effects on cardiovascular and renal events in hypertensive patients with high cardiovascular risks. In the present study, we hypothesized that CCB enhances the protective effects of an angiotensin II type 1 receptor blocker (ARB against diabetic cerebrovascular-renal injury. Saline-drinking type 2 diabetic KK-A(y mice developed hypertension and exhibited impaired cognitive function, blood-brain barrier (BBB disruption, albuminuria, glomerular sclerosis and podocyte injury. These brain and renal injuries were associated with increased gene expression of NADPH oxidase components, NADPH oxidase activity and oxidative stress in brain and kidney tissues as well as systemic oxidative stress. Treatment with the ARB, olmesartan (10 mg/kg/day reduced blood pressure in saline-drinking KK-A(y mice and attenuated cognitive decline, BBB disruption, glomerular injury and albuminuria, which were associated with a reduction of NADPH oxidase activity and oxidative stress in brain and kidney tissues as well as systemic oxidative stress. Furthermore, a suppressive dose of azelnidipine (3 mg/kg/day exaggerated these beneficial effects of olmesartan. These data support the hypothesis that a CCB enhances ARB-associated cerebrovascular-renal protective effects through suppression of NADPH oxidase-dependent oxidative stress in type 2 diabetes.

  14. Association of Angiotensin-Converting Enzyme Intron 16 Insertion/Deletion and Angiotensin II Type 1 Receptor A1166C Gene Polymorphisms with Preeclampsia in South East of Iran

    Directory of Open Access Journals (Sweden)

    Saeedeh Salimi

    2011-01-01

    Full Text Available Some evidence suggests that a variety of genetic factors contributed in pathogenesis of the preeclampsia. The aim of this study was to assess the association between the angiotensin-converting enzyme (ACE I/D and angiotensin II type1 receptor A1166C polymorphisms with preeclampsia. This study was performed in 125 preeclamptic pregnant women and 132 controls. The I/D Polymorphism of the ACE gene was assessed by polymerase chain reaction and the A1166C Polymorphism of the AT1R gene was determined by restriction fragment length polymorphism. The genotype and allele frequencies of I/D polymorphism differed between two groups. The risk of preeclampsia was 3.2-fold in pregnant women with D allele (OR, 3.2 [95% CI, 1.1 to 3.8]; P=0.01. The distribution of the AT1R gene A1166C polymorphism was similar in affected and control groups. Our results supported that presence of the I/D polymorphism of ACE gene is a marker for the increased risk of preeclampsia.

  15. Lipid rafts are required for signal transduction by angiotensin II receptor type 1 in neonatal glomerular mesangial cells.

    Science.gov (United States)

    Adebiyi, Adebowale; Soni, Hitesh; John, Theresa A; Yang, Fen

    2014-05-15

    Angiotensin II (ANG-II) receptors (AGTRs) contribute to renal physiology and pathophysiology, but the underlying mechanisms that regulate AGTR function in glomerular mesangium are poorly understood. Here, we show that AGTR1 is the functional AGTR subtype expressed in neonatal pig glomerular mesangial cells (GMCs). Cyclodextrin (CDX)-mediated cholesterol depletion attenuated cell surface AGTR1 protein expression and ANG-II-induced intracellular Ca(2+) ([Ca(2+)]i) elevation in the cells. The COOH-terminus of porcine AGTR1 contains a caveolin (CAV)-binding motif. However, neonatal GMCs express CAV-1, but not CAV-2 and CAV-3. Colocalization and in situ proximity ligation assay detected an association between endogenous AGTR1 and CAV-1 in the cells. A synthetic peptide corresponding to the CAV-1 scaffolding domain (CSD) sequence also reduced ANG-II-induced [Ca(2+)]i elevation in the cells. Real-time imaging of cell growth revealed that ANG-II stimulates neonatal GMC proliferation. ANG-II-induced GMC growth was attenuated by EMD 66684, an AGTR1 antagonist; BAPTA, a [Ca(2+)]i chelator; KN-93, a Ca(2+)/calmodulin-dependent protein kinase II inhibitor; CDX; and a CSD peptide, but not PD 123319, a selective AGTR2 antagonist. Collectively, our data demonstrate [Ca(2+)]i-dependent proliferative effect of ANG-II and highlight a critical role for lipid raft microdomains in AGTR1-mediated signal transduction in neonatal GMCs. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Adipocyte-Specific Enhancement of Angiotensin II Type 1 Receptor-Associated Protein Ameliorates Diet-Induced Visceral Obesity and Insulin Resistance.

    Science.gov (United States)

    Azushima, Kengo; Ohki, Kohji; Wakui, Hiromichi; Uneda, Kazushi; Haku, Sona; Kobayashi, Ryu; Haruhara, Kotaro; Kinguchi, Sho; Matsuda, Miyuki; Maeda, Akinobu; Toya, Yoshiyuki; Yamashita, Akio; Umemura, Satoshi; Tamura, Kouichi

    2017-03-06

    The renin-angiotensin system has a pivotal role in the pathophysiology of visceral obesity. Angiotensin II type 1 receptor (AT1R) is a major player in the signal transduction of the renin-angiotensin system, and the overactivation of this signaling contributes to the progression of visceral obesity. We have shown that the AT1R-associated protein (ATRAP) promotes AT1R internalization from the cell surface into cytoplasm along with the suppression of overactivation of tissue AT1R signaling. In this study, we examined whether the enhancement of adipose ATRAP expression could efficiently prevent diet-induced visceral obesity and insulin resistance. We generated adipocyte-specific ATRAP transgenic mice using a 5.4-kb adiponectin promoter, and transgenic mice and littermate control mice were fed either a low- or high-fat diet for 10 weeks. Although the physiological phenotypes of the transgenic and control mice fed a low-fat diet were comparable, the transgenic mice exhibited significant protection against high-fat diet-induced adiposity, adipocyte hypertrophy, and insulin resistance concomitant with an attenuation of adipose inflammation, macrophage infiltration, and adipokine dysregulation. In addition, when mice were fed a high-fat diet, the adipose expression of glucose transporter type 4 was significantly elevated and the level of adipose phospho-p38 mitogen-activated protein kinase was significantly attenuated in the transgenic mice compared with control mice. Results presented in this study suggested that the enhancement in adipose ATRAP plays a protective role against the development of diet-induced visceral obesity and insulin resistance through improvement of adipose inflammation and function via the suppression of overactivation of adipose AT1R signaling. Consequently, adipose tissue ATRAP is suggested to be an effective therapeutic target for the treatment of visceral obesity. © 2017 The Authors. Published on behalf of the American Heart Association, Inc

  17. Comparative Effects of Direct Renin Inhibitor and Angiotensin Receptor Blocker on Albuminuria in Hypertensive Patients with Type 2 Diabetes. A Randomized Controlled Trial

    Science.gov (United States)

    Uzu, Takashi; Araki, Shin-ichi; Kashiwagi, Atsunori; Haneda, Masakazu; Koya, Daisuke; Yokoyama, Hiroki; Kida, Yasuo; Ikebuchi, Motoyoshi; Nakamura, Takaaki; Nishimura, Masataka; Takahara, Noriko; Obata, Toshiyuki; Omichi, Nobuyuki; Sakamoto, Katsuhiko; Shingu, Ryosuke; Taki, Hideki; Nagai, Yoshio; Tokuda, Hiroaki; Kitada, Munehiro; Misawa, Miwa; Nishiyama, Akira; Kobori, Hiroyuki; Maegawa, Hiroshi

    2016-01-01

    Background In patients with diabetes, albuminuria is a risk marker of end-stage renal disease and cardiovascular events. An increased renin-angiotensin system activity has been reported to play an important role in the pathological processes in these conditions. We compared the effect of aliskiren, a direct renin inhibitor (DRI), with that of angiotensin receptor blockers (ARBs) on albuminuria and urinary excretion of angiotensinogen, a marker of intrarenal renin-angiotensin system activity. Methods We randomly assigned 237 type 2 diabetic patients with high-normal albuminuria (10 to <30 mg/g of albumin-to-creatinine ratio) or microalbuminuria (30 to <300 mg/g) to the DRI group or ARB group (any ARB) with a target blood pressure of <130/80 mmHg. The primary endpoint was a reduction in albuminuria. Results Twelve patients dropped out during the observation period, and a total of 225 patients were analyzed. During the study period, the systolic and diastolic blood pressures were not different between the groups. The changes in the urinary albumin-to-creatinine ratio from baseline to the end of the treatment period in the DRI and ARB groups were similar (-5.5% and -6.7%, respectively). In contrast, a significant reduction in the urinary excretion of angiotensinogen was observed in the ARB group but not in the DRI group. In the subgroup analysis, a significant reduction in the albuminuria was observed in the ARB group but not in the DRI group among high-normal albuminuria patients. Conclusion DRI and ARB reduced albuminuria in hypertensive patients with type 2 diabetes. In addition, ARB, but not DRI, reduced albuminuria even in patients with normal albuminuria. DRI is not superior to ARB in the reduction of urinary excretion of albumin and angiotensinogen. PMID:28033332

  18. Update on angiotensin AT2 receptors.

    Science.gov (United States)

    Carey, Robert M

    2017-03-01

    This review updates major new findings and concepts introduced during the past year on the role of angiotensin II (Ang II) subtype 2 receptors (AT2Rs) in the control of blood pressure and renal function. AT2R activation prevents sodium (Na) retention and lowers blood pressure in the Ang II infusion model of experimental hypertension and prevents salt-sensitive hypertension in the obese Zucker rat model of obesity and the metabolic syndrome. Ang II metabolite, des-aspartyl-Ang II (Ang III) is the predominant AT2R agonist in the kidney and possibly also in the vasculature; a novel synthetic Ang III peptide, β-Pro-Ang III, is vasodepressor and lowers blood pressure in conscious spontaneously hypertensive rats in the presence of low-level Ang II type 1 receptor (AT1R) blockade. Because nitric oxide is a product of AT2R activation, a potential feed-forward loop, wherein nitric oxide increases AT2R transcription, may reinforce the beneficial actions of AT2R in the long term. AT2R activation also reduces proteinuria and oxidative stress in glomerulosclerotic kidneys of high-salt obese Zucker rats. Studies during the past year have helped to clarify the physiological and pathophysiological roles of AT2Rs and have enhanced the promise of AT2R agonists in cardiovascular and renal disease.

  19. Excess of Aminopeptidase A in the Brain Elevates Blood Pressure via the Angiotensin II Type 1 and Bradykinin B2 Receptors without Dipsogenic Effect

    Directory of Open Access Journals (Sweden)

    Takuto Nakamura

    2017-01-01

    Full Text Available Aminopeptidase A (APA cleaves angiotensin (Ang II, kallidin, and other related peptides. In the brain, it activates the renin angiotensin system and causes hypertension. Limited data are available on the dipsogenic effect of APA and pressor effect of degraded peptides of APA such as bradykinin. Wistar-Kyoto rats received intracerebroventricular (icv APA in a conscious, unrestrained state after pretreatment with (i vehicle, (ii 80 μg of telmisartan, an Ang II type-1 (AT1 receptor blocker, (iii 800 nmol of amastatin, an aminopeptidase inhibitor, and (iv 1 nmol of HOE-140, a bradykinin B2 receptor blocker. Icv administration of 400 and 800 ng of APA increased blood pressure by 12.6 ± 3.0 and 19.0 ± 3.1 mmHg, respectively. APA did not evoke drinking behavior. Pressor response to APA was attenuated on pretreatment with telmisartan (vehicle: 22.1 ± 2.2 mmHg versus telmisartan: 10.4 ± 3.2 mmHg. Pressor response to APA was also attenuated with amastatin and HOE-140 (vehicle: 26.5 ± 1.1 mmHg, amastatin: 14.4 ± 4.2 mmHg, HOE-140: 16.4 ± 2.2 mmHg. In conclusion, APA increase in the brain evokes a pressor response via enzymatic activity without dipsogenic effect. AT1 receptors and B2 receptors in the brain may contribute to the APA-induced pressor response.

  20. Excess of Aminopeptidase A in the Brain Elevates Blood Pressure via the Angiotensin II Type 1 and Bradykinin B2 Receptors without Dipsogenic Effect

    Science.gov (United States)

    Ishida, Akio; Ohya, Yusuke

    2017-01-01

    Aminopeptidase A (APA) cleaves angiotensin (Ang) II, kallidin, and other related peptides. In the brain, it activates the renin angiotensin system and causes hypertension. Limited data are available on the dipsogenic effect of APA and pressor effect of degraded peptides of APA such as bradykinin. Wistar-Kyoto rats received intracerebroventricular (icv) APA in a conscious, unrestrained state after pretreatment with (i) vehicle, (ii) 80 μg of telmisartan, an Ang II type-1 (AT1) receptor blocker, (iii) 800 nmol of amastatin, an aminopeptidase inhibitor, and (iv) 1 nmol of HOE-140, a bradykinin B2 receptor blocker. Icv administration of 400 and 800 ng of APA increased blood pressure by 12.6 ± 3.0 and 19.0 ± 3.1 mmHg, respectively. APA did not evoke drinking behavior. Pressor response to APA was attenuated on pretreatment with telmisartan (vehicle: 22.1 ± 2.2 mmHg versus telmisartan: 10.4 ± 3.2 mmHg). Pressor response to APA was also attenuated with amastatin and HOE-140 (vehicle: 26.5 ± 1.1 mmHg, amastatin: 14.4 ± 4.2 mmHg, HOE-140: 16.4 ± 2.2 mmHg). In conclusion, APA increase in the brain evokes a pressor response via enzymatic activity without dipsogenic effect. AT1 receptors and B2 receptors in the brain may contribute to the APA-induced pressor response. PMID:28421141

  1. Angiotensin-(1-7 Prevents Skeletal Muscle Atrophy Induced by Transforming Growth Factor Type Beta (TGF-β via Mas Receptor Activation

    Directory of Open Access Journals (Sweden)

    Johanna Ábrigo

    2016-11-01

    Full Text Available Background: Transforming growth factor type beta 1 (TGF-β1 produces skeletal muscle atrophy. Angiotensin-(1-7 (Ang-(1-7, through the Mas receptor, prevents the skeletal muscle atrophy induced by sepsis, immobilization, or angiotensin II (Ang-II. However, the effect of Ang-(1-7 on muscle wasting induced by TGF-β1 is unknown. Aim: To evaluate whether Ang-(1-7/Mas receptor axis could prevent the skeletal muscle atrophy induced by TGF-β1. Methods: This study assessed the atrophic effect of TGF-β1 in C2C12 myotubes and mice in absence or presence of Ang-(1-7, and the receptor participation using A779, an antagonist of the Mas receptor. The levels of myosin heavy chain (MHC, polyubiquitination, and MuRF-1 were detected by western blot. Myotube diameter was also evaluated. In vivo analysis included the muscle strength, fibre diameter, MHC and MuRF-1 levels by western blot, and ROS levels by DCF probe detection. Results: The results showed that Ang-(1-7 prevented the increase in MuRF-1 and polyubiquitined protein levels, the decrease of MHC levels, the myotubes/fibre diameter diminution, and the increased production of reactive oxygen species (ROS induced by TGF-β1. Utilizing A779 inhibited the anti-atrophic effect of Ang-(1-7. Conclusion: The preventive effect of Ang-(1-7 on skeletal muscle atrophy induced by TGF-β1 is produced through inhibition of ROS production and proteasomal degradation of MHC.

  2. Combined Angiotensin Receptor Antagonism and Neprilysin Inhibition.

    Science.gov (United States)

    Hubers, Scott A; Brown, Nancy J

    2016-03-15

    Heart failure affects ≈5.7 million people in the United States alone. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, and aldosterone antagonists have improved mortality in patients with heart failure and reduced ejection fraction, but mortality remains high. In July 2015, the US Food and Drug Administration approved the first of a new class of drugs for the treatment of heart failure: Valsartan/sacubitril (formerly known as LCZ696 and currently marketed by Novartis as Entresto) combines the angiotensin receptor blocker valsartan and the neprilysin inhibitor prodrug sacubitril in a 1:1 ratio in a sodium supramolecular complex. Sacubitril is converted by esterases to LBQ657, which inhibits neprilysin, the enzyme responsible for the degradation of the natriuretic peptides and many other vasoactive peptides. Thus, this combined angiotensin receptor antagonist and neprilysin inhibitor addresses 2 of the pathophysiological mechanisms of heart failure: activation of the renin-angiotensin-aldosterone system and decreased sensitivity to natriuretic peptides. In the Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure (PARADIGM-HF) trial, valsartan/sacubitril significantly reduced mortality and hospitalization for heart failure, as well as blood pressure, compared with enalapril in patients with heart failure, reduced ejection fraction, and an elevated circulating level of brain natriuretic peptide or N-terminal pro-brain natriuretic peptide. Ongoing clinical trials are evaluating the role of valsartan/sacubitril in the treatment of heart failure with preserved ejection fraction and hypertension. We review here the mechanisms of action of valsartan/sacubitril, the pharmacological properties of the drug, and its efficacy and safety in the treatment of heart failure and hypertension.

  3. Emerging Role of Angiotensin Type 2 Receptor (AT2R)/Akt/NO Pathway in Vascular Smooth Muscle Cell in the Hyperthyroidism

    Science.gov (United States)

    Carrillo-Sepúlveda, Maria Alícia; Ceravolo, Graziela S.; Furstenau, Cristina R.; Monteiro, Priscilla de Souza; Bruno-Fortes, Zuleica; Carvalho, Maria Helena; Laurindo, Francisco R.; Tostes, Rita C.; Webb, R. Clinton; Barreto-Chaves, Maria Luiza M.

    2013-01-01

    Hyperthyroidism is characterized by increased vascular relaxation and decreased vascular contraction and is associated with augmented levels of triiodothyronine (T3) that contribute to the diminished systemic vascular resistance found in this condition. T3 leads to augmented NO production via PI3K/Akt signaling pathway, which in turn causes vascular smooth muscle cell (VSMC) relaxation; however, the underlying mechanisms involved remain largely unknown. Evidence from human and animal studies demonstrates that the renin-angiotensin system (RAS) plays a crucial role in vascular function and also mediates some of cardiovascular effects found during hyperthyroidism. Thus, in this study, we hypothesized that type 2 angiotensin II receptor (AT2R), a key component of RAS vasodilatory actions, mediates T3 induced-decreased vascular contraction. Marked induction of AT2R expression was observed in aortas from T3-induced hyperthyroid rats (Hyper). These vessels showed decreased protein levels of the contractile apparatus: α-actin, calponin and phosphorylated myosin light chain (p-MLC). Vascular reactivity studies showed that denuded aortic rings from Hyper rats exhibited decreased maximal contractile response to angiotensin II (AngII), which was attenuated in aortic rings pre-incubated with an AT2R blocker. Further study showed that cultured VSMC stimulated with T3 (0.1 µmol/L) for 24 hours had increased AT2R gene and protein expression. Augmented NO levels and decreased p-MLC levels were found in VSMC stimulated with T3, both of which were reversed by a PI3K/Akt inhibitor and AT2R blocker. These findings indicate for the first time that the AT2R/Akt/NO pathway contributes to decreased contractile responses in rat aorta, promoted by T3, and this mechanism is independent from the endothelium. PMID:23637941

  4. Emerging role of angiotensin type 2 receptor (AT2R/Akt/NO pathway in vascular smooth muscle cell in the hyperthyroidism.

    Directory of Open Access Journals (Sweden)

    Maria Alícia Carrillo-Sepúlveda

    Full Text Available Hyperthyroidism is characterized by increased vascular relaxation and decreased vascular contraction and is associated with augmented levels of triiodothyronine (T3 that contribute to the diminished systemic vascular resistance found in this condition. T3 leads to augmented NO production via PI3K/Akt signaling pathway, which in turn causes vascular smooth muscle cell (VSMC relaxation; however, the underlying mechanisms involved remain largely unknown. Evidence from human and animal studies demonstrates that the renin-angiotensin system (RAS plays a crucial role in vascular function and also mediates some of cardiovascular effects found during hyperthyroidism. Thus, in this study, we hypothesized that type 2 angiotensin II receptor (AT2R, a key component of RAS vasodilatory actions, mediates T3 induced-decreased vascular contraction. Marked induction of AT2R expression was observed in aortas from T3-induced hyperthyroid rats (Hyper. These vessels showed decreased protein levels of the contractile apparatus: α-actin, calponin and phosphorylated myosin light chain (p-MLC. Vascular reactivity studies showed that denuded aortic rings from Hyper rats exhibited decreased maximal contractile response to angiotensin II (AngII, which was attenuated in aortic rings pre-incubated with an AT2R blocker. Further study showed that cultured VSMC stimulated with T3 (0.1 µmol/L for 24 hours had increased AT2R gene and protein expression. Augmented NO levels and decreased p-MLC levels were found in VSMC stimulated with T3, both of which were reversed by a PI3K/Akt inhibitor and AT2R blocker. These findings indicate for the first time that the AT2R/Akt/NO pathway contributes to decreased contractile responses in rat aorta, promoted by T3, and this mechanism is independent from the endothelium.

  5. Aldosterone breakthrough caused by chronic blockage of angiotensin II type 1 receptors in human adrenocortical cells: possible involvement of bone morphogenetic protein-6 actions.

    Science.gov (United States)

    Otani, Hiroyuki; Otsuka, Fumio; Inagaki, Kenichi; Suzuki, Jiro; Miyoshi, Tomoko; Kano, Yoshihiro; Goto, Junko; Ogura, Toshio; Makino, Hirofumi

    2008-06-01

    Circulating aldosterone concentrations occasionally increase after initial suppression with angiotensin II (Ang II) converting enzyme inhibitors or Ang II type 1 receptor blockers (ARBs), a phenomenon referred to as aldosterone breakthrough. However, the underlying mechanism causing the aldosterone breakthrough remains unknown. Here we investigated whether aldosterone breakthrough occurs in human adrenocortical H295R cells in vitro. We recently reported that bone morphogenetic protein (BMP)-6, which is expressed in adrenocortical cells, enhances Ang II- but not potassium-induced aldosterone production in human adrenocortical cells. Accordingly, we examined the roles of BMP-6 in aldosterone breakthrough induced by long-term treatment with ARB. Ang II stimulated aldosterone production by adrenocortical cells. This Ang II stimulation was blocked by an ARB, candesartan. Interestingly, the candesartan effects on Ang II-induced aldosterone synthesis and CYP11B2 expression were attenuated in a course of candesartan treatment for 15 d. The impairment of candesartan effects on Ang II-induced aldosterone production was also observed in Ang II- or candesartan-pretreated cells. Levels of Ang II type 1 receptor mRNA were not changed by chronic candesartan treatment. However, BMP-6 enhancement of Ang II-induced ERK1/2 signaling was resistant to candesartan. The BMP-6-induced Smad1, -5, and -8 phosphorylation, and BRE-Luc activity was augmented in the presence of Ang II and candesartan in the chronic phase. Chronic Ang II exposure decreased cellular expression levels of BMP-6 and its receptors activin receptor-like kinase-2 and activin type II receptor mRNAs. Cotreatment with candesartan reversed the inhibitory effects of Ang II on the expression levels of these mRNAs. The breakthrough phenomenon was attenuated by neutralization of endogenous BMP-6 and activin receptor-like kinase-2. Collectively, these data suggest that changes in BMP-6 availability and response may be involved

  6. Lipid rafts are required for signal transduction by angiotensin II receptor type 1 in neonatal glomerular mesangial cells

    Energy Technology Data Exchange (ETDEWEB)

    Adebiyi, Adebowale, E-mail: aadebiyi@uthsc.edu; Soni, Hitesh; John, Theresa A.; Yang, Fen

    2014-05-15

    Angiotensin II (ANG-II) receptors (AGTRs) contribute to renal physiology and pathophysiology, but the underlying mechanisms that regulate AGTR function in glomerular mesangium are poorly understood. Here, we show that AGTR1 is the functional AGTR subtype expressed in neonatal pig glomerular mesangial cells (GMCs). Cyclodextrin (CDX)-mediated cholesterol depletion attenuated cell surface AGTR1 protein expression and ANG-II-induced intracellular Ca{sup 2+} ([Ca{sup 2+}]{sub i}) elevation in the cells. The COOH-terminus of porcine AGTR1 contains a caveolin (CAV)-binding motif. However, neonatal GMCs express CAV-1, but not CAV-2 and CAV-3. Colocalization and in situ proximity ligation assay detected an association between endogenous AGTR1 and CAV-1 in the cells. A synthetic peptide corresponding to the CAV-1 scaffolding domain (CSD) sequence also reduced ANG-II-induced [Ca{sup 2+}]{sub i} elevation in the cells. Real-time imaging of cell growth revealed that ANG-II stimulates neonatal GMC proliferation. ANG-II-induced GMC growth was attenuated by EMD 66684, an AGTR1 antagonist; BAPTA, a [Ca{sup 2+}]{sub i} chelator; KN-93, a Ca{sup 2+}/calmodulin-dependent protein kinase II inhibitor; CDX; and a CSD peptide, but not PD 123319, a selective AGTR2 antagonist. Collectively, our data demonstrate [Ca{sup 2+}]{sub i}-dependent proliferative effect of ANG-II and highlight a critical role for lipid raft microdomains in AGTR1-mediated signal transduction in neonatal GMCs. - Highlights: • AGTR1 is the functional AGTR subtype expressed in neonatal mesangial cells. • Endogenous AGTR1 associates with CAV-1 in neonatal mesangial cells. • Lipid raft disruption attenuates cell surface AGTR1 protein expression. • Lipid raft disruption reduces ANG-II-induced [Ca{sup 2+}]{sub i} elevation in neonatal mesangial cells. • Lipid raft disruption inhibits ANG-II-induced neonatal mesangial cell growth.

  7. Discovery of a series of imidazo[4,5-b]pyridines with dual activity at angiotensin II type 1 receptor and peroxisome proliferator-activated receptor-γ.

    Science.gov (United States)

    Casimiro-Garcia, Agustin; Filzen, Gary F; Flynn, Declan; Bigge, Christopher F; Chen, Jing; Davis, Jo Ann; Dudley, Danette A; Edmunds, Jeremy J; Esmaeil, Nadia; Geyer, Andrew; Heemstra, Ronald J; Jalaie, Mehran; Ohren, Jeffrey F; Ostroski, Robert; Ellis, Teresa; Schaum, Robert P; Stoner, Chad

    2011-06-23

    Mining of an in-house collection of angiotensin II type 1 receptor antagonists to identify compounds with activity at the peroxisome proliferator-activated receptor-γ (PPARγ) revealed a new series of imidazo[4,5-b]pyridines 2 possessing activity at these two receptors. Early availability of the crystal structure of the lead compound 2a bound to the ligand binding domain of human PPARγ confirmed the mode of interaction of this scaffold to the nuclear receptor and assisted in the optimization of PPARγ activity. Among the new compounds, (S)-3-(5-(2-(1H-tetrazol-5-yl)phenyl)-2,3-dihydro-1H-inden-1-yl)-2-ethyl-5-isobutyl-7-methyl-3H-imidazo[4,5-b]pyridine (2l) was identified as a potent angiotensin II type I receptor blocker (IC(50) = 1.6 nM) with partial PPARγ agonism (EC(50) = 212 nM, 31% max) and oral bioavailability in rat. The dual pharmacology of 2l was demonstrated in animal models of hypertension (SHR) and insulin resistance (ZDF rat). In the SHR, 2l was highly efficacious in lowering blood pressure, while robust lowering of glucose and triglycerides was observed in the male ZDF rat.

  8. Discovery of a Series of Imidazo[4,5-b]pyridines with Dual Activity at Angiotensin II Type 1 Receptor and Peroxisome Proliferator-Activated Receptor-[gamma

    Energy Technology Data Exchange (ETDEWEB)

    Casimiro-Garcia, Agustin; Filzen, Gary F.; Flynn, Declan; Bigge, Christopher F.; Chen, Jing; Davis, Jo Ann; Dudley, Danette A.; Edmunds, Jeremy J.; Esmaeil, Nadia; Geyer, Andrew; Heemstra, Ronald J.; Jalaie, Mehran; Ohren, Jeffrey F.; Ostroski, Robert; Ellis, Teresa; Schaum, Robert P.; Stoner, Chad (Pfizer)

    2013-03-07

    Mining of an in-house collection of angiotensin II type 1 receptor antagonists to identify compounds with activity at the peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) revealed a new series of imidazo[4,5-b]pyridines 2 possessing activity at these two receptors. Early availability of the crystal structure of the lead compound 2a bound to the ligand binding domain of human PPAR{gamma} confirmed the mode of interaction of this scaffold to the nuclear receptor and assisted in the optimization of PPAR{gamma} activity. Among the new compounds, (S)-3-(5-(2-(1H-tetrazol-5-yl)phenyl)-2,3-dihydro-1H-inden-1-yl)-2-ethyl-5-isobutyl-7-methyl-3H-imidazo[4,5-b]pyridine (2l) was identified as a potent angiotensin II type I receptor blocker (IC{sub 50} = 1.6 nM) with partial PPAR{gamma} agonism (EC{sub 50} = 212 nM, 31% max) and oral bioavailability in rat. The dual pharmacology of 2l was demonstrated in animal models of hypertension (SHR) and insulin resistance (ZDF rat). In the SHR, 2l was highly efficacious in lowering blood pressure, while robust lowering of glucose and triglycerides was observed in the male ZDF rat.

  9. A method for developing high-density SNP maps and its application at the type 1 angiotensin II receptor (AGTR1) locus.

    Science.gov (United States)

    Antonellis, Anthony; Rogus, John J; Canani, Luis H; Makita, Yuchiro; Pezzolesi, Marcus G; Nam, MoonSuk; Ng, Daniel; Moczulski, Dariusz; Warram, James H; Krolewski, Andrzej S

    2002-03-01

    Evaluating the potential genetic components of complex disease will likely be aided through the use of dense polymorphism maps. Previously, we reported evidence for linkage with diabetic nephropathy on chromosome 3q in a region encompassing the type 1 angiotensin II receptor (AGTR1) gene. To further investigate any role for this gene in disease onset, we set out to design a dense polymorphism map spanning the AGTR1 locus for the purpose of association studies. Toward this goal, we have developed a technique for rapid identification of polymorphisms in long stretches of genomic DNA. This approach uses long-range PCR, DNA pooling, and transposon-based DNA sequencing. Using this technique, we efficiently validated and genotyped 18 polymorphisms spanning the 60.5-kb AGTR1 locus. Our panel of polymorphisms has an average spacing of 3.2 kb and an average minor allele frequency of 24%.

  10. Angiotensin Type 2 Receptor Stimulation Ameliorates Left Ventricular Fibrosis and Dysfunction via Regulation of Tissue Inhibitor of Matrix Metalloproteinase 1/Matrix Metalloproteinase 9 Axis and Transforming Growth Factor β1 in the Rat Heart

    DEFF Research Database (Denmark)

    Lauer, Dilyara; Slavic, Svetlana; Sommerfeld, Manuela;

    2014-01-01

    mechanisms may be. MI was induced in Wistar rats by permanent ligation of the left coronary artery. Treatment with the angiotensin type 2 receptor agonist compound 21 ( 0.03 mg/kg) was started 6 hours post-MI and continued for 6 weeks. Hemodynamic parameters were measured by echocardiography and intracardiac...

  11. Angiotensintypereceptor agonistic autoantibody-induced apoptosis in neonatal rat cardiomyocytes is dependent on the generation of tumor necrosis factor-α

    Institute of Scientific and Technical Information of China (English)

    Weiran Chai; Wenhui Zhang; Zhu Jin; Yiping Feng; Yanping Kuang; Jianming Zhi

    2012-01-01

    Angiotensintypereceptor agonistic autoantibodies (AT1-AA) are related to pre-eclampsia and hypertension and have a direct effect of stimulating the production of tumor necrosis factor-alpha (TNF-α) in the placenta.TNF-α is a known mediator of apoptosis.However,few studies have reported the role of TNF-α and its relationship within AT1-AA-induced apoptosis of cardiomyocytes.In this study,neonatal rat cardiomyocytes were treated with various concentrations of AT1-AA.The apoptosis of neonatal rat cardiomyocytes was determined using TUNEL assay and flow cytometry.The level of secreted TNF-α was measured by enzyme-linked immunosorbent assay,and caspase-3 activity was measured by a fluorogenic protease assay kit.AT1 receptor blockade and TNF inhibitor were added to determine whether they could inhibit the apoptotic effect of AT1-AA.Results showed that AT1-AA induced the apoptosis of neonatal rat cardiomyocytes in a dose-dependent and time-dependent manner.AT1-AA increased TNF secretion and caspase-3activities.AT1 receptor blockade completely abrogated AT1-AA-induced TNF-α secretion,caspase-3 activation,and cardiomyocyte apoptosis.TNF-α receptor inhibitor significantly attenuated AT1-AA-induced neonatal rat cardiomyocyte apoptosis.AT1-AA in the plasma of preeclamptic patients promoted neonatal rat cardiomyocyte apoptosis through a TNF-caspase signaling pathway.

  12. Angiotensin II receptors in the gonads

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera, G.; Millan, M.A.; Harwood, J.P.

    1989-05-01

    The presence of components of the renin-angiotensin system in ovaries and testes suggests that angiotensin II (AII) is involved in gonadal function, and thus we sought to characterize receptors for AII in rat and primate gonads. In the testes, autoradiographic studies showed receptors in the interstitium in all species. In rat interstitial cells fractionated by Percoll gradient, AII receptors coincided with hCG receptors indicating that AII receptors are located on the Leydig cells. In Leydig cells and membranes from rat and rhesus monkey prepuberal testes, AII receptors were specific for AII analogues and of high affinity (Kd=nM). During development, AII receptor content in rat testes decreases with age parallel to a fall in the ratio of interstitial to tubular tissue. In the ovary, the distribution of AII receptors was dependent on the stage of development, being high in the germinal epithelium and stromal tissue between five and 15 days, and becoming localized in secondary follicles in 20-and 40-day-old rats. No binding was found in primordial or primary follicles. In rhesus monkey ovary, AII receptors were higher in stromal tissue and lower in granulosa and luteal cells of the follicles. Characterization of the binding in rat and monkey ovarian membranes showed a single class of sites with a Kd in the nmol/L range and specificity similar to that of the adrenal glomerulosa and testicular AII receptors. Receptors for AII were also present in membrane fractions from PMSG/hCG primed rat ovaries. Infusion of AII (25 ng/min) or captopril (1.4 micrograms/min) during the PMSG/hCG induction period had no effect on ovarian weight or AII receptor concentration in the ovaries.

  13. When Should We Start Using Angiotensin Converting Enzyme Inhibitors/Angiotensin Receptor Blockers in Diabetic Kidney Disease?

    Directory of Open Access Journals (Sweden)

    D.D. Ivanov

    2017-03-01

    Full Text Available International guidelines do not recommend angiotensin converting enzyme (ACE inhibitors/angiotensin receptor blockers (ARBs usage in the first stage of diabetic kidney disease. It shows the view, based on a small statistical sample, that olmesartan (or possibly other ACE inhibitors/ARBs should be used to prevent the transition of the first stage of diabetic kidney disease to the second one in type 2 diabetes mellitus.

  14. Targeting Angiotensin II Type-1 Receptor (AT1R) Inhibits the Harmful Phenotype of Plasmodium-Specific CD8(+) T Cells during Blood-Stage Malaria.

    Science.gov (United States)

    Silva-Filho, João L; Caruso-Neves, Celso; Pinheiro, Ana A S

    2017-01-01

    CD8(+) T-cell response is critical in the pathogenesis of cerebral malaria during blood-stage. Our group and other have been shown that angiotensin II (Ang II) and its receptor AT1 (AT1R), a key effector axis of renin-angiotensin system (RAS), have immune regulatory effects on T cells. Previously, we showed that inhibition of AT1R signaling protects mice against the lethal disease induced by Plasmodium berghei ANKA infection However, most of the Ang II/AT1R actions were characterized by using only pharmacological approaches, the effects of which may not always be due to a specific receptor blockade. In addition, the mechanisms of action of the AT1R in inducing the pathogenic activity of Plasmodium-specific CD8(+) T cells during blood-stage were not determined. Here, we examined how angiotensin II/AT1R axis promotes the harmful response of Plasmodium-specific CD8(+) T-cell during blood-stage by using genetic and pharmacological approaches. We evaluated the response of wild-type (WT) and AT1R(-/-)Plasmodium-specific CD8(+) T cells in mice infected with a transgenic PbA lineage expressing ovalbumin; and in parallel infected mice receiving WT Plasmodium-specific CD8(+) T cells were treated with losartan (AT1R antagonist) or captopril (ACE inhibitor). Both, AT1R(-/-) OT-I cells and WT OT-I cells from losartan- or captopril-treated mice showed lower expansion, reduced IL-2 production and IL-2Rα expression, lower activation (lower expression of CD69, CD44 and CD160) and lower exhaustion profiles. AT1R(-/-) OT-I cells also exhibit lower expression of the integrin LFA-1 and the chemokine receptors CCR5 and CXCR3, known to play a key role in the development of cerebral malaria. Moreover, AT1R(-/-) OT-I cells produce lower amounts of IFN-γ and TNF-α and show lower degranulation upon restimulation. In conclusion, our results show the pivotal mechanisms of AT1R-induced harmful phenotype of Plasmodium-specific CD8(+) T cells during blood-stage malaria.

  15. Targeting Angiotensin II Type-1 Receptor (AT1R) Inhibits the Harmful Phenotype of Plasmodium-Specific CD8+ T Cells during Blood-Stage Malaria

    Science.gov (United States)

    Silva-Filho, João L.; Caruso-Neves, Celso; Pinheiro, Ana A. S.

    2017-01-01

    CD8+ T-cell response is critical in the pathogenesis of cerebral malaria during blood-stage. Our group and other have been shown that angiotensin II (Ang II) and its receptor AT1 (AT1R), a key effector axis of renin-angiotensin system (RAS), have immune regulatory effects on T cells. Previously, we showed that inhibition of AT1R signaling protects mice against the lethal disease induced by Plasmodium berghei ANKA infection However, most of the Ang II/AT1R actions were characterized by using only pharmacological approaches, the effects of which may not always be due to a specific receptor blockade. In addition, the mechanisms of action of the AT1R in inducing the pathogenic activity of Plasmodium-specific CD8+ T cells during blood-stage were not determined. Here, we examined how angiotensin II/AT1R axis promotes the harmful response of Plasmodium-specific CD8+ T-cell during blood-stage by using genetic and pharmacological approaches. We evaluated the response of wild-type (WT) and AT1R−/− Plasmodium-specific CD8+ T cells in mice infected with a transgenic PbA lineage expressing ovalbumin; and in parallel infected mice receiving WT Plasmodium-specific CD8+ T cells were treated with losartan (AT1R antagonist) or captopril (ACE inhibitor). Both, AT1R−/− OT-I cells and WT OT-I cells from losartan- or captopril-treated mice showed lower expansion, reduced IL-2 production and IL-2Rα expression, lower activation (lower expression of CD69, CD44 and CD160) and lower exhaustion profiles. AT1R−/− OT-I cells also exhibit lower expression of the integrin LFA-1 and the chemokine receptors CCR5 and CXCR3, known to play a key role in the development of cerebral malaria. Moreover, AT1R−/− OT-I cells produce lower amounts of IFN-γ and TNF-α and show lower degranulation upon restimulation. In conclusion, our results show the pivotal mechanisms of AT1R-induced harmful phenotype of Plasmodium-specific CD8+ T cells during blood-stage malaria. PMID:28261571

  16. Effects of Hyperglycemia on Angiotensin II Receptor Type 1 Expression and Insulin Secretion in an INS-1E Pancreatic Beta-Cell Line

    Directory of Open Access Journals (Sweden)

    Kwan Keung Leung

    2008-05-01

    Full Text Available Context A local pancreatic islet renin-angiotensin system has been identified and found to be upregulated in type 2 diabetes mellitus. Inhibition of this system improves beta-cell function and structure. The effects of hyperglycemia, a condition observed in diabetes, on angiotensin II type 1 receptor (AT1R expression and beta-cell secretory function have yet to be explored. Objective This study investigated the effects of chronic hyperglycemia (glucotoxicity on the expression of AT1Rs, and possibly thereby on oxidative stress-induced insulin release, in an INS-1E beta-cell line. Settings INS-1E beta-cells cultured and incubated in different glucose concentrations with a varying time course. Main outcome measures Immunocytochemistry was employed for the precise localization of AT1Rs in INS-1E cells. The effects of hyperglycemia-induced AT1R expression changes in gene and protein levels were examined by real-time RT-PCR and Western blot analysis, respectively. AT1R activation-mediated oxidative stress was assessed by changes in NADPH oxidase expression, and the level of superoxide production was determined by nitroblue tetrazolium (NBT assay. Glucotoxicity-induced AT1R activation- mediated secretory dysfunction was also assessed by insulin release from INS-1E cells Results AT1R immunoreactivity was found to be localized specifically on the cell membrane. Chronic hyperglycemia resulted in dose-dependent upregulation of AT1R gene and protein expression accompanied by concomitantly-enhanced oxidative stress. Glucose-stimulated insulin secretion via AT1R activation was impaired by hyperglycemia. Conclusion These data indicate that hyperglycemia-induced AT1R activation impairs insulin secretion; this impairment may be mediated via AT1R-dependent oxidative stress.

  17. Structural determinants for binding to angiotensin converting enzyme 2 (ACE2 and angiotensin receptors

    Directory of Open Access Journals (Sweden)

    Daniel eClayton

    2015-01-01

    Full Text Available Angiotensin converting enzyme 2 (ACE2 is a zinc carboxypeptidase involved in the renin angiotensin system (RAS and inactivates the potent vasopressive peptide angiotensin II (Ang II by removing the C-terminal phenylalanine residue to yield Ang1-7. This conversion inactivates the vasoconstrictive action of Ang II and yields a peptide that acts as a vasodilatory molecule at the Mas receptor and potentially other receptors. Given the growing complexity of RAS and level of cross-talk between ligands and their corresponding enzymes and receptors, the design of molecules with selectivity for the major RAS binding partners to control cardiovascular tone is an on-going challenge. In previous studies we used single β-amino acid substitutions to modulate the structure of Ang II and its selectivity for ACE2, AT1R and angiotensin type 2 (AT2R receptor. We showed that modification at the C-terminus of Ang II generally resulted in more pronounced changes to secondary structure and ligand binding, and here we further explore this region for the potential to modulate ligand specificity. In this study, 1 a library of forty-seven peptides derived from the C-terminal tetra-peptide sequence (-IHPF of Ang II was synthesised and assessed for ACE2 binding, 2 the terminal group requirements for high affinity ACE2 binding were explored by and N- and C-terminal modification, 3 high affinity ACE2 binding chimeric AngII analogues were then synthesized and assessed, 4 the structure of the full-length Ang II analogues were assessed by circular dichroism, and 5 the Ang II analogues were assessed for AT1R/AT2R selectivity by cell-based assays. Studies on the C-terminus of Ang II demonstrated varied specificity at different residue positions for ACE2 binding and four Ang II chimeric peptides were identified as selective ligands for the AT2 receptor. Overall, these results provide insight into the residue and structural requirements for ACE2 binding and angiotensin receptor

  18. Economic evaluations of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in type 2 diabetic nephropathy : a systematic review

    NARCIS (Netherlands)

    Huang, Yunyu; Zhou, Qiyun; Haaijer-Ruskamp, Flora M.; Postma, Maarten J.

    2014-01-01

    Background: Structured comparison of pharmacoeconomic analyses for ACEIs and ARBs in patients with type 2 diabetic nephropathy is still lacking. This review aims to systematically review the cost-effectiveness of both ACEIs and ARBs in type 2 diabetic patients with nephropathy. Methods: A systematic

  19. Economic evaluations of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in type 2 diabetic nephropathy : a systematic review

    NARCIS (Netherlands)

    Huang, Yunyu; Zhou, Qiyun; Haaijer-Ruskamp, Flora M.; Postma, Maarten J.

    2014-01-01

    Background: Structured comparison of pharmacoeconomic analyses for ACEIs and ARBs in patients with type 2 diabetic nephropathy is still lacking. This review aims to systematically review the cost-effectiveness of both ACEIs and ARBs in type 2 diabetic patients with nephropathy. Methods: A systematic

  20. Cleavage of the angiotensin II type 1 receptor and nuclear accumulation of the cytoplasmic carboxy-terminal fragment.

    Science.gov (United States)

    Cook, Julia L; Mills, Sarah J; Naquin, Ryan T; Alam, Jawed; Re, Richard N

    2007-04-01

    Our published studies show that the distribution of the ANG II type 1 (AT(1)) receptor (AT(1)R), expressed as a enhanced yellow fluorescent fusion (YFP) protein (AT(1)R/EYFP), is altered upon cellular treatment with ANG II or coexpression with intracellular ANG II. AT(1)R accumulates in nuclei of cells only in the presence of ANG II. Several transmembrane receptors are known to accumulate in nuclei, some as holoreceptors and others as cleaved receptor products. The present study was designed to determine whether the AT(1)R is cleaved before nuclear transport. A plasmid encoding a rat AT(1)R labeled at the amino terminus with enhanced cyan fluorescent protein (CFP) and at the carboxy terminus with EYFP was employed. Image analyses of this protein in COS-7 cells, CCF-STTG1 glial cells, and A10 vascular smooth muscle cells show the two fluorescent moieties to be largely spatially colocalized in untreated cells. ANG II treatment, however, leads to a separation of the fluorescent moieties with yellow fluorescence accumulating in more than 30% of cellular nuclei. Immunoblot analyses of extracts and conditioned media from transfected cells indicate that the CFP domain fused to the extracellular amino-terminal AT(1)R domain is cleaved from the membrane and that the YFP domain, together with the intracellular cytoplasmic carboxy terminus of the AT(1)R, is also cleaved from the membrane-bound receptor. The carboxy terminus of the AT(1)R is essential for cleavage; cleavage does not occur in protein deleted with respect to this region. Overexpressed native AT(1)R (nonfusion) is also cleaved; the intracellular 6-kDa cytoplasmic domain product accumulates to a significantly higher level with ANG II treatment.

  1. Advances in angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs).

    Science.gov (United States)

    Swamy, K M K; Lin, Mei-Jung; Sun, Chung-Ming

    2003-09-01

    Hypertension remains one of the most unmet medical needs of this century. While many drugs are available for treating hypertension, efforts are still insufficient to find potent therapeutic agents since cause for hypertension in all patients is not the same. Angiotensin-converting enzyme inhibitors (ACEIs) have emerged as an important class of drugs in the treatment of hypertension, congestive heart failure (CHF), protenuric renal disease, myocardial infarction and stroke. This class of drugs blocks the conversion of angiotensin I to angiotensin II and prevents bradykinin breakdown. However, the lack of specificity of ACEIs leads to the frequent side effects like cough and angio-oedema. Recently developed, specific non-peptide and orally active angiotensin receptor blockers (ARBs) have become the prime therapeutics as they alone or co-administration with ACE inhibitors can control the renin angiotensin disorders. This review explores recent developments in the design, synthesis, and structural modifications of ACE inhibitors as well as angiotensin receptor blockers.

  2. Role of Mas receptor antagonist (A779) on pressure diuresis and natriuresis and renal blood flow in the absence of angiotensin II receptors type 1 and 2 in female and male rats.

    Science.gov (United States)

    Mansoori, A; Oryan, S; Nematbakhsh, M

    2014-10-01

    Sexual differences in blood pressure are associated with angiotensin 1-7 (Ang1-7) and its receptor and enzyme function targeting. Blockade of angiotensin II (AngII) receptors type 1 and 2 (AT1R and AT2R) inhibits some actions of Ang1-7. We described the role of Ang1-7 receptor (MasR) antagonist (A779) on kidney hemodynamics when AT1R and AT2R are blocked with losartan and PD123319. In anaesthetized male and female rats after blockade of both AT1R and AT2R, the renal perfusion pressure (RPP) was controlled in two levels of 80 and 100 mmHg via an adjustable clamp placed around the aorta above the level of the renal arteries. Then, the effects of saline vehicle and MasR blocker (A779) were tested on pressure natriuresis and diuresis, renal blood flow (RBF), and renal vascular resistance (RVR). In the absence of AT1R and AT2R; RVR, RBF/wet kidney tissue weight, and serum level of renin did not alter in both genders either MasR was blocked or not. However, urine flow rate (UF) and sodium excretion (UNaV) increased significantly at the pressure level of 100 mmHg in the presence of MasR in male (Pdiuresis, and pressure natriuresis and diuresis in male rats (not female) increases in the presence of MasR.

  3. The Prognostic Role of Angiotensin II Type 1 Receptor Autoantibody in Non-Gravid Hypertension and Pre-eclampsia: A Meta-analysis and Our Studies.

    Science.gov (United States)

    Lei, Jinghui; Li, Yafeng; Zhang, Suli; Wu, Ye; Wang, Pengli; Liu, Huirong

    2016-04-01

    Angiotensin II type 1 receptor autoantibody (AT1-AA) is found in patients with non-gravid hypertension or pre-eclampsia, but the relationship is uncertain.The aim of the present study was to assess the association between AT1-AA and high blood pressure using meta-analysis, and to evaluate the prognosis value of AT1-AA for hypertensive diseases.Literature search from PubMed, Embase, and Cochrane databases were conducted using keywords "hypertension" or "pre-eclampsia," "angiotensin II receptor type 1 autoantibody," and its aliases from April 1999 to December 2015.Studies evaluating the association between AT1-AA and non-gravid hypertension or pre-eclampsia were included in this analysis. The quality of the eligible studies was assessed based on the Newcastle-Ottawa Scale with some modifications.Two researchers then independently reviewed all included studies and extracted all relevant data. Association between AT1-AA and hypertension was tested with pooled odds ratios (ORs) and 95% confidence intervals (CIs). Finally, we evaluated whether AT1-AA predicted the prognosis of hypertension by using a summary receiver-operating characteristic (ROC) curve and sensitivity analysis.Ten studies were finally included in this meta-analysis. AT1-AA showed more significant association with pre-eclampsia than that with non-gravid hypertension (pooled OR 32.84, 95% CI 17.19-62.74; and pooled OR 4.18, 95% CI 2.20-7.98, respectively). Heterogeneity among studies was also detected probably due to different hypertensive subtypes and AT1-AA measuring methods. Area under summary ROC curve (AUC) of pre-eclampsia was 0.92 (sensitivity 0.76; specificity 0.86). Area under the ROC curve of overall hypertensive diseases or non-gravid hypertension was lower than that of pre-eclampsia (0.86 and 0.72, respectively) with lower sensitivities (0.46 and 0.26, respectively).The major limitation of this analysis was the publication bias due to lack of unpublished data and the language limitation during

  4. Economic evaluations of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in type 2 diabetic nephropathy: a systematic review.

    Science.gov (United States)

    Huang, Yunyu; Zhou, Qiyun; Haaijer-Ruskamp, Flora M; Postma, Maarten J

    2014-01-15

    Structured comparison of pharmacoeconomic analyses for ACEIs and ARBs in patients with type 2 diabetic nephropathy is still lacking. This review aims to systematically review the cost-effectiveness of both ACEIs and ARBs in type 2 diabetic patients with nephropathy. A systematic literature search was performed in MEDLINE and EMBASE for the period from November 1, 1999 to Oct 31, 2011. Two reviewers independently assessed the quality of the articles included and extracted data. All cost-effectiveness results were converted to 2011 Euros. Up to October 2011, 434 articles were identified. After full-text checking and quality assessment, 30 articles were finally included in this review involving 39 study settings. All 6 ACEIs studies were literature-based evaluations which synthesized data from different sources. Other 33 studies were directed at ARBs and were designed based on specific trials. The Markov model was the most common decision analytic method used in the evaluations. From the cost-effectiveness results, 37 out of 39 studies indicated either ACEIs or ARBs were cost-saving comparing with placebo/conventional treatment, such as amlodipine. A lack of evidence was assessed for valid direct comparison of cost-effectiveness between ACEIs and ARBs. There is a lack of direct comparisons of ACEIs and ARBs in existing economic evaluations. Considering the current evidence, both ACEIs and ARBs are likely cost-saving comparing with conventional therapy, excluding such RAAS inhibitors.

  5. Absence of angiotensin II type 1 receptor in bone marrow–derived cells is detrimental in the evolution of renal fibrosis

    Science.gov (United States)

    Nishida, Masashi; Fujinaka, Hidehiko; Matsusaka, Taiji; Price, James; Kon, Valentina; Fogo, Agnes B.; Davidson, Jeffrey M.; Linton, MacRae F.; Fazio, Sergio; Homma, Toshio; Yoshida, Hiroaki; Ichikawa, Iekuni

    2002-01-01

    We examined the in vivo function of the angiotensin II type 1 receptor (Agtr1) on macrophages in renal fibrosis. Fourteen days after the induction of unilateral ureteral obstruction (UUO), wild-type mice reconstituted with marrow lacking the Agtr1 gene (Agtr1–/–) developed more severe interstitial fibrosis with fewer interstitial macrophages than those in mice reconstituted with Agtr1+/+ marrow. These differences were not observed at day 5 of UUO. The expression of profibrotic genes — including TGF-β1, α1(I) collagen, and α1(III) collagen — was substantially higher in the obstructed kidneys of mice with Agtr1–/– marrow than in those with Agtr1+/+ marrow at day 14 but not at day 5 of UUO. Mice with Agtr1–/– marrow were characterized by reduced numbers of peripheral-blood monocytes and macrophage progenitors in bone marrow. In vivo assays revealed a significantly impaired phagocytic capability in Agtr1–/– macrophages. In vivo treatment of Agtr1+/+ mice with losartan reduced phagocytic capability of Agtr1+/+ macrophages to a level comparable to that of Agtr1–/– macrophages. Thus, during urinary tract obstruction, the Agtr1 on bone marrow–derived macrophages functions to preserve the renal parenchymal architecture, and this function depends in part on its modulatory effect on phagocytosis. PMID:12488436

  6. Trends in co-prescribing of angiotensin converting enzyme inhibitors and angiotensin receptor blockers in Ireland.

    LENUS (Irish Health Repository)

    Wan Md Adnan, Wan A H

    2011-03-01

    (i) To examine the trends in co-prescribing of angiotensin converting enzyme inhibitor (ACEI) and angiotensin-II receptor blocker (ARB) therapy and (ii) to examine the influence of major clinical trials (CALM, COOPERATE, VALIANT and ONTARGET) on co-prescribing.

  7. Angiotensin-converting enzyme inhibition or angiotensin receptor blockade in hypertensive diabetics?

    NARCIS (Netherlands)

    Laverman, G; Ruggenenti, P; Remuzzi, G

    2003-01-01

    Hypertension increases the renal and cardiovascular risks in diabetic patients. The beneficial effects of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on renal and cardiovascular outcomes are discussed in this paper, with a particular focus on their optimal use in the

  8. TNF-α type 2 receptor mediates renal inflammatory response to chronic angiotensin II administration with high salt intake in mice.

    Science.gov (United States)

    Singh, Purnima; Bahrami, Laleh; Castillo, Alexander; Majid, Dewan S A

    2013-04-01

    Tumor necrosis factor-alpha (TNF-α) has been implicated in salt-sensitive hypertension and renal injury (RI) induced by angiotensin II (ANG II). To determine the receptor type of TNF-α involved in this mechanism, we evaluated the responses to chronic ANG II infusion (25 ng/min by implanted minipump) given with high-salt diet (HS; 4% NaCl) for 2 wk in gene knockout mice for TNF-α receptor type 1 (TNFR1KO; n = 6) and type 2 (TNFR2KO; n = 6) and compared the responses with those in wild-type (WT; C57BL/6; n = 6) mice. Blood pressure in these mice was measured by implanted radiotelemetry as well as by tail-cuff plethysmography. RI responses were assessed by measuring macrophage cell infiltration (CD68(+) immunohistochemistry), glomerulosclerosis (PAS staining), and interstitial fibrosis (Gomori's trichrome staining) in renal tissues at the end of the treatment period. The increase in mean arterial pressure induced by ANG II + HS treatment was not different in these three groups of mice (TNFR1KO, 114 ± 1 to 161 ± 7 mmHg; TNFR2KO, 113 ± 1 to 161 ± 3 mmHg; WT, 110 ± 3 to 154 ± 3 mmHg). ANG II + HS-induced RI changes were similar in TNFR1KO mice but significantly less in TNFR2KO mice (macrophage infiltration, 0.02 ± 0.01 vs. 1.65 ± 0.45 cells/mm(2); glomerulosclerosis, 26.3 ± 2.6 vs. 35.7 ± 2.2% area; and interstitial fibrosis, 5.2 ± 0.6 vs. 8.1 ± 1.1% area) compared with the RI changes in WT mice. The results suggest that a direct activation of TNF-α receptors may not be required in inducing hypertensive response to chronic ANG II administration with HS intake, but the induction of inflammatory responses leading to renal injury are mainly mediated by TNF-α receptor type 2.

  9. Differential expression of angiotensin II type 1 and type 2 receptors at the maternal-fetal interface: potential roles in early placental development.

    Science.gov (United States)

    Tower, C L; Lui, S; Charlesworth, N R; Smith, S D; Aplin, J D; Jones, R L

    2010-12-01

    Angiotensin II (Ang II) is locally generated in the placenta and regulates syncytial transport, vascular contractility and trophoblast invasion. It acts through two receptor subtypes, AGTR1 and AGTR2 (AT1 and AT2), which typically mediate antagonising actions. The objectives of this study are to characterise the cellular distribution of AGTR1 and AGTR2 at the maternal-fetal interface and explore the effects on cytotrophoblast turnover. Low levels of AGTR2 mRNA were detected in first trimester placental homogenates using real-time PCR. Immunohistochemistry using polyclonal antibodies against AGTR1 and AGTR2 detected the receptors in first trimester placenta, decidua basalis and villous tip outgrowths in culture. Serial staining with cytokeratin-7 was used to identify extravillous trophoblasts (EVTs). AGTR1 was found in the syncytiotrophoblast microvillous membrane, in a subpopulation of villous cytotrophoblasts, and in Hofbauer cells. AGTR1 was strongly upregulated in cytotrophoblasts in cell columns and villous tip outgrowths, but was absent in interstitial and endovascular EVTs within the decidua. AGTR2 immunostaining was present in Hofbauer cells and villous cytotrophoblasts, but was absent from syncytiotrophoblast. Faint staining was detected in cell column cytotrophoblasts and villous outgrowths, but not in EVTs within the decidua. Both receptors were detected in placental homogenates by western blotting. Ang II significantly increased proliferation of cytotrophoblasts in both villous explants and villous tip outgrowths, but did not affect apoptosis. Blockade of AGTR1 and AGTR2 together abrogated this effect. This study shows specific expression patterns for AGTR1 and AGTR2 in distinct trophoblast populations at the maternal-fetal interface and suggests that Ang II plays a role in placental development and generation of EVTs.

  10. Inhibitory Effect of the Punica granatum Fruit Extract on Angiotensin-II Type I Receptor and Thromboxane B2 in Endothelial Cells Induced by Plasma from Preeclamptic Patients.

    Science.gov (United States)

    Kusumawati, Widya; Keman, Kusnarman; Soeharto, Setyawati

    2016-01-01

    This study aims to evaluate whether the Punica granatum fruit extract modulates the Angiotensin-II Type I receptor (AT1-R) and thromboxane B2 level in endothelial cells induced by plasma from preeclamptic patients. Endothelial cells were obtained from human umbilical vascular endothelial cells. At confluence, endothelial cells were divided into five groups, which included endothelial cells exposed to 2% plasma from normal pregnancy (NP), endothelial cells exposed to 2% plasma from preeclamptic patients (PP), and endothelial cells exposed to PP in the presence of ethanolic extract of Punica granatum (PP + PG) at the following three doses: 14; 28; and 56 ppm. The expression of AT1-R was observed by immunohistochemistry technique, and thromboxane B2 level was done by immunoassay technique. Plasma from PP significantly increased AT1-R expression and thromboxane B2 levels compared to cells treated by normal pregnancy plasma. The increasing of AT1-R expression significantly (P Punica granatum extract. Moreover, the increasing of thromboxane B2 levels significantly (P Punica granatum extract. We further concluded that Punica granatum fruit protects and inhibits the sensitivity of endothelial cells to plasma from preeclamptic patients due to inhibition of AT1-R expression (56 ppm) and reduced thromboxane B2 levels (14 ppm).

  11. Efficacy and Safety of Combination Therapy Consisting of Angiotensin II Type 1 Receptor Blocker, Calcium Channel Blocker and Hydrochlorothiazide in Patients With Hypertension

    Science.gov (United States)

    Shiga, Yuhei; Miura, Shin-ichiro; Motozato, Kota; Yoshimine, Yuka; Norimatsu, Kenji; Arimura, Tadaaki; Koyoshi, Rie; Morii, Joji; Kuwano, Takashi; Inoue, Ken; Shirotani, Tetsuro; Fujisawa, Kazuaki; Matsunaga, Eiyu; Saku, Keijiro

    2017-01-01

    Background Many patients continue to have high blood pressure (BP) even after treatment with high-dose (H)-angiotensin II type 1 receptor blocker (ARB)/calcium channel blocker (CCB) or middle-dose (M)-ARB/CCB/hydrochlorothiazide (HCTZ). Methods Thirty-two hypertensive patients who had the use of H-ARB/CCB or M-ARB/CCB/HCTZ were enrolled in this study. We applied a changeover with a switch to H-ARB (telmisartan 80 mg/day)/CCB (amlodipine 5 mg/day or nifedipine CR 40 mg/day)/HCTZ (12.5 mg/day). Results Systolic BP (SBP) and diastolic BP (DBP) were significantly decreased in all patients and in the H-ARB/CCB and M-ARB/CCB/HCTZ groups after 3 months. Percentage (%) of patients who reached the target BP after 3 months (72%) in all patients was significantly higher than that at 0 months (19%). There were no serious adverse effects in any of the patients. Conclusions Combination therapy with H-ARB/CCB/HCTZ was associated with a significant reduction of BP. PMID:28090225

  12. Role of interleukin-10 in the neuroprotective effect of the Angiotensin Type 2 Receptor agonist, compound 21, after ischemia/reperfusion injury.

    Science.gov (United States)

    Fouda, Abdelrahman Y; Pillai, Bindu; Dhandapani, Krishnan M; Ergul, Adviye; Fagan, Susan C

    2017-03-15

    We and others have shown that the angiotensin type 2 (AT2) receptor agonist, compound 21 (C21), provides neuroprotection and enhances recovery in rodent stroke models yet the mechanism involved is not known. Moreover, C21 treatment is associated with an anti-inflammatory response. Here we tested the hypothesis that C21 mediates neuroprotection by upregulating the neuroprotective and anti-inflammatory cytokine, interleukin (IL)-10. Wistar rats were subjected to 3h-middle cerebral artery suture occlusion and treated at reperfusion with C21 (0.03mg/kg)±IL-10 neutralizing antibody (0.1mg/kg) both given i.p. Infarct size, behavioral outcomes, and molecular analysis were performed at 24h post-injury. Primary rat neurons were used to test the direct neuroprotective effect of C21 in vitro. C21 treatment reduced infarct size, improved functional outcome and decreased the pro-inflammatory cytokine, tumor necrosis factor alpha (TNF-α) in the ischemic hemisphere compared to saline. Anti-IL-10 co-treatment blocked the C21-induced reduction in infarct size and inflammation, and the improvement in behavioral outcome. In vitro, C21 treatment increased neuron survival and reduced cell apoptosis after oxygen glucose deprivation (OGD) and OGD/reoxygenation. These effects were mediated through AT2R stimulation. C21 provides direct neuroprotection as well as indirect protection through IL-10. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Paracrine Effects of Adipose-Derived Stem Cells on Matrix Stiffness-Induced Cardiac Myofibroblast Differentiation via Angiotensin II Type 1 Receptor and Smad7

    Science.gov (United States)

    Yong, Kar Wey; Li, Yuhui; Liu, Fusheng; Bin Gao; Lu, Tian Jian; Wan Abas, Wan Abu Bakar; Wan Safwani, Wan Kamarul Zaman; Pingguan-Murphy, Belinda; Ma, Yufei; Xu, Feng; Huang, Guoyou

    2016-01-01

    Human mesenchymal stem cells (hMSCs) hold great promise in cardiac fibrosis therapy, due to their potential ability of inhibiting cardiac myofibroblast differentiation (a hallmark of cardiac fibrosis). However, the mechanism involved in their effects remains elusive. To explore this, it is necessary to develop an in vitro cardiac fibrosis model that incorporates pore size and native tissue-mimicking matrix stiffness, which may regulate cardiac myofibroblast differentiation. In the present study, collagen coated polyacrylamide hydrogel substrates were fabricated, in which the pore size was adjusted without altering the matrix stiffness. Stiffness is shown to regulate cardiac myofibroblast differentiation independently of pore size. Substrate at a stiffness of 30 kPa, which mimics the stiffness of native fibrotic cardiac tissue, was found to induce cardiac myofibroblast differentiation to create in vitro cardiac fibrosis model. Conditioned medium of hMSCs was applied to the model to determine its role and inhibitory mechanism on cardiac myofibroblast differentiation. It was found that hMSCs secrete hepatocyte growth factor (HGF) to inhibit cardiac myofibroblast differentiation via downregulation of angiotensin II type 1 receptor (AT1R) and upregulation of Smad7. These findings would aid in establishment of the therapeutic use of hMSCs in cardiac fibrosis therapy in future. PMID:27703175

  14. Angiotensin type 2 receptor stimulation ameliorates left ventricular fibrosis and dysfunction via regulation of tissue inhibitor of matrix metalloproteinase 1/matrix metalloproteinase 9 axis and transforming growth factor β1 in the rat heart.

    Science.gov (United States)

    Lauer, Dilyara; Slavic, Svetlana; Sommerfeld, Manuela; Thöne-Reineke, Christa; Sharkovska, Yuliya; Hallberg, Anders; Dahlöf, Bjorn; Kintscher, Ulrich; Unger, Thomas; Steckelings, Ulrike Muscha; Kaschina, Elena

    2014-03-01

    Left ventricular (LV) remodeling is the main reason for the development of progressive cardiac dysfunction after myocardial infarction (MI). This study investigated whether stimulation of the angiotensin type 2 receptor is able to ameliorate post-MI cardiac remodeling and what the underlying mechanisms may be. MI was induced in Wistar rats by permanent ligation of the left coronary artery. Treatment with the angiotensin type 2 receptor agonist compound 21 (0.03 mg/kg) was started 6 hours post-MI and continued for 6 weeks. Hemodynamic parameters were measured by echocardiography and intracardiac catheter. Effects on proteolysis were studied in heart tissue and primary cardiac fibroblasts. Compound 21 significantly improved systolic and diastolic functions, resulting in improved ejection fraction (71.2±4.7% versus 53.4±7.0%; Pventricular filling velocities, and maximum and minimum rate of LV pressure rise (P<0.05). Compound 21 improved arterial stiffness parameters and reduced collagen content in peri-infarct myocardium. Tissue inhibitor of matrix metalloproteinase 1 was strongly upregulated, whereas matrix metalloproteinases 2 and 9 and transforming growth factor β1 were diminished in LV of treated animals. In cardiac fibroblasts, compound 21 initially induced tissue inhibitor of matrix metalloproteinase 1 expression followed by attenuated matrix metalloproteinase 9 and transforming growth factor β1 secretion. In conclusion, angiotensin type 2 receptor stimulation improves cardiac function and prevents cardiac remodeling in the late stage after MI, suggesting that angiotensin type 2 receptor agonists may be considered a future pharmacological approach for the improvement of post-MI cardiac dysfunction.

  15. Angiotensin receptor blockers in heart failure after the ELITE II trial

    Directory of Open Access Journals (Sweden)

    Willenheimer Ronnie

    2000-09-01

    Full Text Available Abstract Specific blockers of the angiotensin type1 receptor, angiotensin receptor blockers (ARBs, have been introduced as an alternative to angiotensin-converting enzyme inhibitors (ACEi for the treatment of heart failure. In comparison with ACEi, ARBs are better tolerated and have similar effects on haemodynamics, neurohormones and exercise capacity. Early studies have suggested that ARBs might have a superior effect on mortality. However, the first outcome trial, ELITE II (Losartan Heart Failure Survival Study, did not show any significant difference between losartan and captopril in terms of mortality or morbidity. This commentary outlines the role of ARBs in the treatment of heart failure.

  16. Additive effects of cilnidipine, an L-/N-type calcium channel blocker, and an angiotensin II receptor blocker on reducing cardiorenal damage in Otsuka Long-Evans Tokushima Fatty rats with type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Mori Y

    2014-06-01

    Full Text Available Yutaka Mori,1,2 Shizuka Aritomi,3 Kazumi Niinuma,3 Tarou Nakamura,3 Kenichi Matsuura,1 Junichi Yokoyama,1 Kazunori Utsunomiya1 1Division of Diabetes and Endocrinology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Japan; 2Department of Clinical Research, National Hospital Organization, Utsunomiya National Hospital, Utsunomiya, Japan; 3Research Center, Ajinomoto Pharmaceuticals Co, Ltd, Kanagawa, Japan Abstract: Cilnidipine (Cil, which is an L-/N-type calcium channel blocker (CCB, has been known to provide renal protection by decreasing the activity of the sympathetic nervous system (SNS and the renin–angiotensin system. In this study, we compared the effects of the combination of Cil and amlodipine (Aml, which is an L-type CCB, with an angiotensin (Ang II receptor blocker on diabetic cardiorenal damage in spontaneously type 2 diabetic rats. Seventeen-week-old Otsuka Long-Evans Tokushima Fatty rats were randomly assigned to receive Cil, Aml, valsartan (Val, Cil + Val, Aml + Val, or a vehicle (eight rats per group for 22 weeks. Antihypertensive potencies were nearly equal among the CCB monotherapy groups and the combination therapy groups. The lowering of blood pressure by either treatment did not significantly affect the glycemic variables. However, exacerbations of renal and heart failure were significantly suppressed in rats administered Cil or Val, and additional suppression was observed in those administered Cil + Val. Although Val increased the renin–Ang system, Aml + Val treatment resulted in additional increases in these parameters, while Cil + Val did not show such effects. Furthermore, Cil increased the ratio of Ang-(1–7 to Ang-I, despite the fact that Val and Aml + Val decreased the Ang-(1–7 levels. These actions of Cil + Val might be due to their synergistic inhibitory effect on the activity of the SNS, and on aldosterone secretion through N-type calcium channel antagonism and Ang II

  17. Identification of Distinct Conformations of the Angiotensin-II Type 1 Receptor Associated with the Gq/11 Protein Pathway and the β-Arrestin Pathway Using Molecular Dynamics Simulations*

    Science.gov (United States)

    Cabana, Jérôme; Holleran, Brian; Leduc, Richard; Escher, Emanuel; Guillemette, Gaétan; Lavigne, Pierre

    2015-01-01

    Biased signaling represents the ability of G protein-coupled receptors to engage distinct pathways with various efficacies depending on the ligand used or on mutations in the receptor. The angiotensin-II type 1 (AT1) receptor, a prototypical class A G protein-coupled receptor, can activate various effectors upon stimulation with the endogenous ligand angiotensin-II (AngII), including the Gq/11 protein and β-arrestins. It is believed that the activation of those two pathways can be associated with distinct conformations of the AT1 receptor. To verify this hypothesis, microseconds of molecular dynamics simulations were computed to explore the conformational landscape sampled by the WT-AT1 receptor, the N111G-AT1 receptor (constitutively active and biased for the Gq/11 pathway), and the D74N-AT1 receptor (biased for the β-arrestin1 and -2 pathways) in their apo-forms and in complex with AngII. The molecular dynamics simulations of the AngII-WT-AT1, N111G-AT1, and AngII-N111G-AT1 receptors revealed specific structural rearrangements compared with the initial and ground state of the receptor. Simulations of the D74N-AT1 receptor revealed that the mutation stabilizes the receptor in the initial ground state. The presence of AngII further stabilized the ground state of the D74N-AT1 receptor. The biased agonist [Sar1,Ile8]AngII also showed a preference for the ground state of the WT-AT1 receptor compared with AngII. These results suggest that activation of the Gq/11 pathway is associated with a specific conformational transition stabilized by the agonist, whereas the activation of the β-arrestin pathway is linked to the stabilization of the ground state of the receptor. PMID:25934394

  18. The Angiotensin AT2 Receptor

    DEFF Research Database (Denmark)

    Unger, Thomas; Steckelings, Ulrike M.; Dzau, Victor J.

    2015-01-01

    -angiotensin system (RAS) mediated by the angiotensin AT1 receptor. Intensive research over the years has revealed major characteristics of the AT2R as a modulatory player involved in antiproliferation, anti-inflammation, natriuresis, neuroregeneration, and apoptosis, that is, -biological...

  19. Effects of angiotensin converting enzyme inhibitor, angio- tensin II type I receptor blocker and their combination on postinfarcted ventricular remodeling in rats

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Background Transforming growth factor (TGF) β1-Smads signal plays an important role in cardiac remodeling following myocardial infarction (MI). In addition, both angiotensin converting enzyme inhibitor (ACEI) and angiotensin II type I receptor blocker (ARB) can effectively prevent left ventricular remodeling. The current study focused on whether the combination of ACEI and ARB is more beneficial for preventing ventricular remodeling and whether Smad proteins mediate this beneficial effect.Results VW/BW significantly increased in the placebo groups compared with that in the control group (P<0.01). This increase was limited in ACEI, ARB, and combined groups (P<0.01 compared with placebo group). There was no significant difference among the three actively treated groups. Collagen was increased in placebo group (5.68±0.5)% compared with that in control group (P<0.01). ACEI, ARB and combined treatment attenuated this increase of collagen [(4.3±0.5)%, (3.5±0.5)%, (3.2±0.4)%] in comparison with that in placebo group (P<0.01 respectively). Combined treatment showed more significant effect on collagen deposition. EF and FS significantly decreased, LVDd and E/A significantly increased in placebo group compared with that in control group (P<0.01 respectively). ACEI, ARB and combined treatment ameliorated these indexes (P<0.01 compared with placebo group). The mRNA expression of TGFβ1, Smad 2, and Smad 3 (0.700±0.045, 0.959±0.037 and 0.850±0.051) increased in placebo group compared with that in control group (P<0.01). ACEI, ARB and combined treatment normalized the increase (P<0.01). Furthermore, ARB and combined treatment proved to be more effective in decreasing TGF β1 and Smad mRNA expression than ACEI treatment (P<0.01). The expression of Smad 2 and Smad 3 protein increased in placebo group compared with that in control group (P<0.01). ACEI, ARB and combined treatment normalized the increase (P<0.01). Furthermore, ARB and combined treatment proved to be more

  20. Acute ethanol intake induces superoxide anion generation and mitogen-activated protein kinase phosphorylation in rat aorta: A role for angiotensin type 1 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Yogi, Alvaro; Callera, Glaucia E. [Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario (Canada); Mecawi, André S. [Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP (Brazil); Batalhão, Marcelo E.; Carnio, Evelin C. [Department of General and Specialized Nursing, College of Nursing of Ribeirão Preto, USP, São Paulo (Brazil); Antunes-Rodrigues, José [Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP (Brazil); Queiroz, Regina H. [Department of Clinical, Toxicological and Food Science Analysis, Faculty of Pharmaceutical Sciences, USP, São Paulo (Brazil); Touyz, Rhian M. [Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario (Canada); Tirapelli, Carlos R., E-mail: crtirapelli@eerp.usp.br [Department of Psychiatric Nursing and Human Sciences, Laboratory of Pharmacology, College of Nursing of Ribeirão Preto, USP, Ribeirão Preto, SP (Brazil)

    2012-11-01

    Ethanol intake is associated with increase in blood pressure, through unknown mechanisms. We hypothesized that acute ethanol intake enhances vascular oxidative stress and induces vascular dysfunction through renin–angiotensin system (RAS) activation. Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats. The transient decrease in blood pressure induced by ethanol was not affected by the previous administration of losartan (10 mg/kg; p.o. gavage), a selective AT{sub 1} receptor antagonist. Acute ethanol intake increased plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels. Ethanol induced systemic and vascular oxidative stress, evidenced by increased plasma thiobarbituric acid-reacting substances (TBARS) levels, NAD(P)H oxidase‐mediated vascular generation of superoxide anion and p47phox translocation (cytosol to membrane). These effects were prevented by losartan. Isolated aortas from ethanol-treated rats displayed increased p38MAPK and SAPK/JNK phosphorylation. Losartan inhibited ethanol-induced increase in the phosphorylation of these kinases. Ethanol intake decreased acetylcholine-induced relaxation and increased phenylephrine-induced contraction in endothelium-intact aortas. Ethanol significantly decreased plasma and aortic nitrate levels. These changes in vascular reactivity and in the end product of endogenous nitric oxide metabolism were not affected by losartan. Our study provides novel evidence that acute ethanol intake stimulates RAS activity and induces vascular oxidative stress and redox-signaling activation through AT{sub 1}-dependent mechanisms. These findings highlight the importance of RAS in acute ethanol-induced oxidative damage. -- Highlights: ► Acute ethanol intake stimulates RAS activity and vascular oxidative stress. ► RAS plays a role in acute ethanol-induced oxidative damage via AT{sub 1} receptor activation.

  1. Pharmacological significance of the interplay between angiotensin receptors: MAS receptors as putative final mediators of the effects elicited by angiotensin AT1 receptors antagonists.

    Science.gov (United States)

    Pernomian, Larissa; Pernomian, Laena; Gomes, Mayara S; da Silva, Carlos H T P

    2015-12-15

    The interplay between angiotensin AT1 receptors and MAS receptors relies on several inward regulatory mechanisms from renin-angiotensin system (RAS) including the functional crosstalk between angiotensin II and angiotensin-(1-7), the competitive AT1 antagonism exhibited by angiotensin-(1-7), the antagonist feature assigned to AT1/MAS heterodimerization on AT1 signaling and the AT1-mediated downregulation of angiotensin-converting enzyme 2 (ACE2). Recently, such interplay has acquired an important significance to RAS Pharmacology since a few studies have supporting strong evidences that MAS receptors mediate the effects elicited by AT1 antagonists. The present Perspective provides an overview of the regulatory mechanisms involving AT1 and MAS receptors, their significance to RAS Pharmacology and the future directions on the interplay between angiotensin receptors. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Prevention of diabetic nephropathy by compound 21, selective agonist of angiotensin type 2 receptors, in Zucker diabetic fatty rats

    DEFF Research Database (Denmark)

    Castoldi, Giovanna; di Gioia, Cira Rt; Bombardi, Camila

    2014-01-01

    Aim of the study was to evaluate the effect of compound 21 (C21), selective AT2 receptor agonist, in diabetic nephropathy and the potential additive effect of C21, when associated to losartan treatment, on the development of albuminuria and renal fibrosis in Zucker diabetic fatty (ZDF) rats. The ...

  3. Effect of angiotensin receptor blockers in the prevention of type 2 diabetes and cardiovascular events: a meta-analysis of randomized trials

    Institute of Scientific and Technical Information of China (English)

    SONG Hui-fen; WANG Su; LI Hong-wei

    2012-01-01

    Background As the incidence of type 2 diabetes is rapidly increasing,prevention of the disease should be considered as a crucial objective in the near future.Several studies have shown angiotensin receptor blockers (ARBs) may contribute to the prevention of new-onset type 2 diabetes.This study was conducted to determine if ARBs as monotherapy or combination therapy may experience a decreased incidence of new-onset type 2 diabetes and prevent cardiovascular events.Methods Relevant experimental and clinical studies were identified by searching MEDLINE (1969 to May 30,2011) to extract a consensus of trial data involving the effect of ARBs on prevention of new-onset type 2 diabetes and cardiovascular events.Studies were included if they were randomized controlled trials versus placebo/routine therapy.A random-effects model was utilized.Subgroup and sensitivity analyses were conducted.Results Eleven trials were identified,including 82738 patients.ARBs prevented new-onset type 2 diabetes (odds ratio 0.8 (95% CI 0.76,0.85)).Regardless of indication for use,essential hypertension (seven trials),impaired glucose tolerance (one trial),cardiocerebrovascular disease (two trials) or heart failure (one trial),reductions in new-onset type 2 diabetes were maintained (0.75 (0.69,0.82),0.85 (0.78,0.92),0.80 (0.76,0.85) and 0.80 (0.64,0.99),respectively).No statistical heterogeneity was observed for any evaluation.However,ARBs did not significantly reduce the odds of all-cause mortality,myocardial infarction and heart failure versus control therapy among all of these studies.But ARBs did reduce the odds of cardiac death and heart failure among the heart failure study versus control therapy.Conclusion ARBs have significant ability to reduce risk of developing new-onset type 2 diabetes but does not improve cardiovascular outcomes over the study follow-up periods among all of included studies.

  4. Angiotensin II type 2 receptor (AT2R) localization and antagonist-mediated inhibition of capsaicin responses and neurite outgrowth in human and rat sensory neurons

    OpenAIRE

    Anand, U; Facer, P; Yiangou, Y.; Sinisi, M; Fox, M.; McCarthy, T.; Bountra, C; Korchev, YE; Anand, P

    2012-01-01

    Background The angiotensin II (AngII) receptor subtype 2 (AT2R) is expressed in sensory neurons and may play a role in nociception and neuronal regeneration. Methods We used immunostaining with characterized antibodies to study the localization of AT2R in cultured human and rat dorsal root ganglion (DRG) neurons and a range of human tissues. The effects of AngII and AT2R antagonist EMA401 on capsaicin responses in cultured human and rat (DRG) neurons were measured with calcium imaging, on neu...

  5. Angiotensin II type 2 receptor stimulation improves fatty acid ovarian uptake and hyperandrogenemia in an obese rat model of polycystic ovary syndrome.

    Science.gov (United States)

    Leblanc, Samuel; Battista, Marie-Claude; Noll, Christophe; Hallberg, Anders; Gallo-Payet, Nicole; Carpentier, André C; Vine, Donna F; Baillargeon, Jean-Patrice

    2014-09-01

    Polycystic ovary syndrome (PCOS) is mainly defined by hyperandrogenism but is also characterized by insulin resistance (IR). Studies showed that overexposure of nonadipose tissues to nonesterified fatty acids (NEFA) may explain both IR and hyperandrogenism. Recent studies indicate that treatment with an angiotensin II type 2 receptor (AT2R)-selective agonist improves diet-induced IR. We thus hypothesized that PCOS hyperandrogenism is triggered by ovarian NEFA overexposure and is improved after treatment with an AT2R agonist. Experiments were conducted in 12-week-old female JCR:LA-cp/cp rats, which are characterized by visceral obesity, IR, hyperandrogenism, and polycystic ovaries. Control JCR:LA +/? rats have a normal phenotype. Rats were treated for 8 days with saline or the selective AT2R agonist C21/M24 and then assessed for: 1) fasting testosterone, NEFA, and insulin levels; and 2) an iv 14(R,S)-[(18)F]fluoro-6-thia-heptadecanoic acid test to determine NEFA ovarian tissue uptake (Km). Compared with controls, saline-treated PCOS/cp rats displayed higher insulin (100 vs 5.6 μU/mL), testosterone (0.12 vs 0.04 nmol/L), NEFA (0.98 vs 0.48 mmol/L), and Km (20.7 vs 12.9 nmol/g·min) (all P < .0001). In PCOS/cp rats, C21/M24 did not significantly improve insulin or NEFA but normalized testosterone (P = .004) and Km (P = .009), which were strongly correlated together in all PCOS/cp rats (ρ = 0.74, P = .009). In conclusion, in an obese PCOS rat model, ovarian NEFA uptake and testosterone levels are strongly associated and are both significantly reduced after short-term C21/M24 therapy. These findings provide new information on the role of NEFA in PCOS hyperandrogenemia and suggest a potential role for AT2R agonists in the treatment of PCOS.

  6. Angiotensin II type 2 receptor ligand PD123319 attenuates hyperoxia-induced lung and heart injury at a low dose in newborn rats.

    Science.gov (United States)

    Wagenaar, Gerry T M; Sengers, Rozemarijn M A; Laghmani, El Houari; Chen, Xueyu; Lindeboom, Melissa P H A; Roks, Anton J M; Folkerts, Gert; Walther, Frans J

    2014-08-01

    Intervening in angiotensin (Ang)-II type 2 receptor (AT2) signaling may have therapeutic potential for bronchopulmonary dysplasia (BPD) by attenuating lung inflammation and preventing arterial hypertension (PAH)-induced right ventricular hypertrophy (RVH). We first investigated the role of AT2 inhibition with PD123319 (0.5 and 2 mg·kg(-1)·day(-1)) on the beneficial effect of AT2 agonist LP2-3 (5 μg/kg twice a day) on RVH in newborn rats with hyperoxia-induced BPD. Next we determined the cardiopulmonary effects of PD123319 (0.1 mg·kg(-1)·day(-1)) in two models: early treatment during continuous exposure to hyperoxia for 10 days and late treatment starting on day 6 in rat pups exposed postnatally to hyperoxia for 9 days, followed by a 9-day recovery period in room air. Parameters investigated included lung and heart histopathology, fibrin deposition, vascular leakage, and differential mRNA expression. Ten days of coadministration of LP2-3 and PD123319 abolished the beneficial effects of LP2-3 on RVH in experimental BPD. In the early treatment model PD123319 attenuated cardiopulmonary injury by reducing alveolar septal thickness, pulmonary influx of inflammatory cells, including macrophages and neutrophils, medial wall thickness of small arterioles, and extravascular collagen III deposition, and by preventing RVH. In the late treatment model PD123319 diminished PAH and RVH, demonstrating that PAH is reversible in the neonatal period. At high concentrations PD123319 blocks the beneficial effects of the AT2-agonist LP2-3 on RVH. At low concentrations PD123319 attenuates cardiopulmonary injury by reducing pulmonary inflammation and fibrosis and preventing PAH-induced RVH but does not affect alveolar and vascular development in newborn rats with experimental BPD.

  7. Endogenous hydrogen sulfide is associated with angiotensin II type 1 receptor in a rat model of carbon tetrachloride-induced hepatic fibrosis.

    Science.gov (United States)

    Fan, Hui-Ning; Chen, Ni-Wei; Shen, Wei-Lin; Zhao, Xiang-Yun; Zhang, Jing

    2015-09-01

    The present study aimed to investigate the effects of endogenous hydrogen sulfide (H2S) on the expression levels of angiotensin II type 1 receptor (AGTR1) in a rat model of carbon tetrachloride (CCl4)‑induced hepatic fibrosis. A total of 56 Wistar rats were randomly divided into four groups: Normal control group, model group, sodium hydrosulfide (NaHS) group, and DL‑propargylglycine (PAG) group. Hepatic fibrosis was induced by CCl4. The rats in the PAG group were intraperitoneally injected with PAG, an inhibitor of cystathionine‑γ‑lyase (CSE). The rats in the NaHS group were intraperitoneally injected with NaHS. An equal volume of saline solution was intraperitoneally injected into both the control and model groups. All rats were sacrificed at week three or four following treatment. The serum levels of hyaluronidase (HA), laminin protein (LN), procollagen III (PcIII), and collagen IV (cIV) were detected using ELISA. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and albumin (ALB) were detected using an automatic biochemical analyzer. The liver mRNA expression levels of CSE were detected by reverse transcription‑quantitative polymerase chain reaction. The liver expression levels of AGTR1 and the plasma expression levels of H2S were detected using western blot analyses. The results indicated that the severity of hepatic fibrosis, the serum expression levels of HA, LN, PcIII, cIV, ALT, and AST, the liver expression levels of CSE and AGTR1, and the plasma expression levels of H2S were significantly higher in the PAG group, as compared with the model group (PAGTR1, and the plasma expression levels of H2S were significantly lower in the NaHS group, as compared with the model group (PAGTR1, which may be associated with the delayed progression of hepatic fibrosis.

  8. Angiotensin II type I receptor and miR-155 in endometrial cancers: synergistic antiproliferative effects of anti-miR-155 and losartan on endometrial cancer cells.

    Science.gov (United States)

    Choi, Chel Hun; Park, Young-Ae; Choi, Jung-Joo; Song, Taejong; Song, Sang Yong; Lee, Yoo-Young; Lee, Jeong-Won; Kim, Tae-Joong; Kim, Byoung-Gie; Bae, Duk-Soo

    2012-07-01

    MicroRNA-155 (miR-155) is one of the micro RNAs (miRNA) most consistently involved in neoplastic diseases, and it is known to repress the angiotensin II type 1 receptor (AGTR1). The aim of the present study was to evaluate the expressions of miR-155 and AGTR1, and to clarify the potential efficacy of anti-miR-155, alone and in combination with AGTR1 blocker losartan in endometrial cancers. Expressions of miR-155 and AGTR1 were evaluated using real-time PCR and immunohistochemistry. And the MTT assay was performed in endometrial cancer cells following anti-miR-155 and AGTR1 blocker (losartan) treatment, alone and in combination. miR-155 was over-expressed and AGTR1 was underexpressed in endometrial carcinoma tissues. AGTR1 immunoreactivity was found in six of ten (60.0%) normal endometrium, 11 of 14 (78.6%) endometrial hyperplasia, and 27 of 62 (43.5%) endometrial carcinoma tissues (P=0.051), and patients with AGTR1 expression showed trend towards improved survival after multivariate analysis (P=0.08). We checked that abolishing the function of miR-155 and AGTR1 by anti-miR-155 or losartan inhibited cell survival of endometrial carcinoma cells, respectively, and furthermore, combined treatment showed synergistic effects. In this study, we characterized the expressions of miR-155 and AGTR1 in endometrial tissues. The combined treatment with anti-miR-155 and losartan has a synergistic antiproliferative effect and an improved understanding is required to clarify whether miR-155 and AGTR1 can be used as a novel therapeutic target in endometrial cancer. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Overexpression of angiotensin II type 1 receptor in breast cancer cells induces epithelial-mesenchymal transition and promotes tumor growth and angiogenesis.

    Science.gov (United States)

    Oh, Eunhye; Kim, Ji Young; Cho, Youngkwan; An, Hyunsook; Lee, Nahyun; Jo, Hunho; Ban, Changill; Seo, Jae Hong

    2016-06-01

    The angiotensin II type I receptor (AGTR1) has been implicated in diverse aspects of human disease, from the regulation of blood pressure and cardiovascular homeostasis to cancer progression. We sought to investigate the role of AGTR1 in cell proliferation, epithelial-mesenchymal transition (EMT), migration, invasion, angiogenesis and tumor growth in the breast cancer cell line MCF7. Stable overexpression of AGTR1 was associated with accelerated cell proliferation, concomitant with increased expression of survival factors including poly(ADP-ribose) polymerase (PARP) and X-linked inhibitor of apoptosis (XIAP), as well as extracellular signal-regulated kinase (ERK) activation. AGTR1-overexpressing MCF7 cells were more aggressive than their parent line, with significantly increased activity in migration and invasion assays. These observations were associated with changes in EMT markers, including reduced E-cadherin expression and increased p-Smad3, Smad4 and Snail levels. Treatment with the AGTR1 antagonist losartan attenuated these effects. AGTR1 overexpression also accelerated tumor growth and increased Ki-67 expression in a xenograft model. This was associated with increased tumor angiogenesis, as evidenced by a significant increase in microvessels in the intratumoral and peritumoral areas, and enhanced tumor invasion, with the latter response associated with increased EMT marker expression and matrix metallopeptidase 9 (MMP-9) upregulation. In vivo administration of losartan significantly reduced both tumor growth and angiogenesis. Our findings suggest that AGTR1 plays a significant role in tumor aggressiveness, and its inhibition may have therapeutic implications. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Angiotensin II type 1a receptors in subfornical organ contribute towards chronic intermittent hypoxia-associated sustained increase in mean arterial pressure.

    Science.gov (United States)

    Saxena, Ashwini; Little, Joel T; Nedungadi, T Prashant; Cunningham, J Thomas

    2015-03-01

    Sleep apnea is associated with hypertension. The mechanisms contributing to a sustained increase in mean arterial pressure (MAP) even during normoxic awake-state remain unknown. Rats exposed to chronic intermittent hypoxia for 7 days, a model of the hypoxemia associated with sleep apnea, exhibit sustained increases in MAP even during the normoxic dark phase. Activation of the renin-angiotensin system (RAS) has been implicated in chronic intermittent hypoxia (CIH) hypertension. Since the subfornical organ (SFO) serves as a primary target for the central actions of circulating ANG II, we tested the effects of ANG II type 1a receptor (AT1aR) knockdown in the SFO on the sustained increase in MAP in this CIH model. Adeno-associated virus carrying green fluorescent protein (GFP) and small-hairpin RNA against either AT1aR or a scrambled control sequence (SCM) was stereotaxically injected in the SFO of rats. After recovery, MAP, heart rate, respiratory rate, and activity were continuously recorded using radiotelemetry. In the normoxic groups, the recorded variables did not deviate from the baseline values. Both CIH groups exhibited significant increases in MAP during CIH exposures (P < 0.05). During the normoxic dark phase in the CIH groups, only the SCM-injected group exhibited a sustained increase in MAP (P < 0.05). The AT1aR-CIH group showed significant decreases in FosB/ΔFosB staining in the median preoptic nucleus and the paraventricular nuclei of the hypothalamus compared with the SCM-CIH group. Our data indicate that AT1aRs in the SFO are critical for the sustained elevation in MAP and increased FosB/ΔFosB expression in forebrain autonomic nuclei associated with CIH.

  11. Angiotensin II AT1 receptor antagonists inhibit platelet adhesion and aggregation by nitric oxide release.

    Science.gov (United States)

    Kalinowski, Leszek; Matys, Tomasz; Chabielska, Ewa; Buczko, Włodzimierz; Malinski, Tadeusz

    2002-10-01

    This study investigated the process of nitric oxide (NO) release from platelets after stimulation with different angiotensin II type 1 (AT1)-receptor antagonists and its effect on platelet adhesion and aggregation. Angiotensin II AT1-receptor antagonist-stimulated NO release in platelets was compared with that in human umbilical vein endothelial cells by using a highly sensitive porphyrinic microsensor. In vitro and ex vivo effects of angiotensin II AT1-receptor antagonists on platelet adhesion to collagen and thromboxane A2 analog U46619-induced aggregation were evaluated. Losartan, EXP3174, and valsartan alone caused NO release from platelets and endothelial cells in a dose-dependent manner in the range of 0.01 to 100 micro mol/L, which was attenuated by NO synthase inhibitor N(G)-nitro-L-arginine methyl ester. The angiotensin II AT1-receptor antagonists had more than 70% greater potency in NO release in platelets than in endothelial cells. The degree of inhibition of platelet adhesion (collagen-stimulated) and aggregation (U46619-stimulated) elicited by losartan, EXP3174, and valsartan, either in vitro or ex vivo, closely correlated with the NO levels produced by each of these drugs alone. The inhibiting effects of angiotensin II AT1-receptor antagonists on collagen-stimulated adhesion and U46619-stimulated aggregation of platelets were significantly reduced by pretreatment with N(G)-nitro-L-arginine methyl ester. Neither the AT2 receptor antagonist PD123319, the cyclooxygenase synthase inhibitor indomethacin, nor the selective thromboxane A2/prostaglandin H2 receptor antagonist SQ29,548 had any effect on angiotensin II AT1-receptor antagonist-stimulated NO release in platelets and endothelial cells. The presented studies clearly indicate a crucial role of NO in the arterial antithrombotic effects of angiotensin II AT1-receptor antagonists.

  12. DPP-4 inhibition with alogliptin on top of angiotensin II type 1 receptor blockade ameliorates albuminuria via up-regulation of SDF-1α in type 2 diabetic patients with incipient nephropathy.

    Science.gov (United States)

    Fujita, Hiroki; Taniai, Hisanori; Murayama, Hiroko; Ohshiro, Haruyo; Hayashi, Hikaru; Sato, Seiko; Kikuchi, Nyuko; Komatsu, Taiga; Komatsu, Koga; Komatsu, Kanji; Narita, Takuma; Yamada, Yuichiro

    2014-01-01

    Dipeptidyl peptidase-4 (DPP-4) inhibitor is a new class of anti-diabetic drug which exerts its glucose-lowering action by suppressing the degradation of a gut incretin hormone glucagon-like peptide-1 (GLP-1). To elucidate whether treatment with stronger DPP-4 inhibitor on top of angiotensin II type 1 receptor blocker (ARB) provides greater renal protective effects, we performed a crossover study with two DPP-4 inhibitors, sitagliptin and alogliptin, in twelve type 2 diabetic patients with incipient nephropathy taking ARBs. This study consisted of three treatment periods: sitagliptin 50 mg/day for 4 weeks (first period), alogliptin 25 mg/day for 4 weeks (second period), and sitagliptin 50 mg/day for 4 weeks (third period). Significant changes in body mass index, blood pressure, serum lipids, serum creatinine, estimated glomerular filtration rate, and HbA1c were not observed among the three treatment periods. Reduced urinary levels of albumin and an oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG), increased urinary cAMP levels, and elevated plasma levels of stromal cell-derived factor-1α (SDF-1α) which is a physiological substrate of DPP-4 were observed after the switch from sitagliptin to a stronger DPP-4 inhibitor alogliptin. Given a large body of evidence indicating anti-oxidative action of cAMP and up-regulation of cellular cAMP production by SDF-1α, the present results suggest that more powerful DPP-4 inhibition on top of angiotensin II type 1 receptor blockade would offer additional protection against early-stage diabetic nephropathy beyond that attributed to glycemic control, via reduction of renal oxidative stress by SDF-1α-cAMP pathway activation.

  13. The beta-arrestin pathway-selective type 1A angiotensin receptor (AT1A) agonist [Sar1,Ile4,Ile8]angiotensin II regulates a robust G protein-independent signaling network.

    Science.gov (United States)

    Kendall, Ryan T; Strungs, Erik G; Rachidi, Saleh M; Lee, Mi-Hye; El-Shewy, Hesham M; Luttrell, Deirdre K; Janech, Michael G; Luttrell, Louis M

    2011-06-01

    The angiotensin II peptide analog [Sar(1),Ile(4),Ile(8)]AngII (SII) is a biased AT(1A) receptor agonist that stimulates receptor phosphorylation, β-arrestin recruitment, receptor internalization, and β-arrestin-dependent ERK1/2 activation without activating heterotrimeric G-proteins. To determine the scope of G-protein-independent AT(1A) receptor signaling, we performed a gel-based phosphoproteomic analysis of AngII and SII-induced signaling in HEK cells stably expressing AT(1A) receptors. A total of 34 differentially phosphorylated proteins were detected, of which 16 were unique to SII and eight to AngII stimulation. MALDI-TOF/TOF mass fingerprinting was employed to identify 24 SII-sensitive phosphoprotein spots, of which three (two peptide inhibitors of protein phosphatase 2A (I1PP2A and I2PP2A) and prostaglandin E synthase 3 (PGES3)) were selected for validation and further study. We found that phosphorylation of I2PP2A was associated with rapid and transient inhibition of a β-arrestin 2-associated pool of protein phosphatase 2A, leading to activation of Akt and increased phosphorylation of glycogen synthase kinase 3β in an arrestin signalsome complex. SII-stimulated PGES3 phosphorylation coincided with an increase in β-arrestin 1-associated PGES3 and an arrestin-dependent increase in cyclooxygenase 1-dependent prostaglandin E(2) synthesis. These findings suggest that AT(1A) receptors regulate a robust G protein-independent signaling network that affects protein phosphorylation and autocrine/paracrine prostaglandin production and that these pathways can be selectively modulated by biased ligands that antagonize G protein activation.

  14. The angiotensin II receptor 2 is expressed and mediates angiotensin II signaling in lung fibrosis.

    Science.gov (United States)

    Königshoff, Melanie; Wilhelm, Anke; Jahn, Andreas; Sedding, Daniel; Amarie, Oana Veronica; Eul, Bastian; Seeger, Werner; Fink, Ludger; Günther, Andreas; Eickelberg, Oliver; Rose, Frank

    2007-12-01

    Idiopathic pulmonary fibrosis (IPF) is a severe interstitial lung disease unresponsive to currently available therapies. In IPF, initial alveolar epithelial cell damage leads to activation of fibroblast-(myo)fibroblasts, which deposit an increased amount of a collagen-rich extracellular matrix. Angiotensin II (ANGII) signaling, mediated via angiotensin II receptor type 1 (AGTR1) or type 2 (AGTR2), controls tissue remodeling in fibrosis, but the relevance of AGTR2 remains elusive. In the present study, we demonstrated increased expression of AGTR1 und AGTR2 in human and rodent lung tissues from patients with IPF and mice subjected to bleomycin-induced fibrosis, respectively. Both AGTR1 und AGTR2 localized to interstitial fibroblasts. Quantitative analysis of cell surface expression in primary mouse fibroblasts revealed a significant increase of AGTR2 surface expression in fibrotic fibroblasts, whereas AGTR1 surface expression levels remained similar. ANGII treatment of normal fibroblasts led to enhanced migration and proliferation, which was abrogated after pretreatment with losartan (LOS), an AGTR1 inhibitor. In contrast, in fibrotic fibroblasts, migration and proliferation was modified only by AGTR2, but not AGTR1 inhibition (using PD123319). ANGII-induced effects were mediated via phosphorylation of the mitogen-activated protein kinases p38 and p42/44, which was blocked via LOS and PD123319, respectively. Similar effects of AGTR1 and AGTR2 inhibition were observed using conditioned media of alveolar epithelial cells, a prominent source of ANGII in the lung in vivo. In summary, we conclude that ANGII signaling occurs primarily via AGTR1 in normal fibroblasts, while AGTR2-mediated effects are dominant on activated (myo)-fibroblasts, a receptor switch that may perturb epithelial-mesenchymal interaction, thereby further perpetuating fibrogenesis.

  15. Angiotensin II receptor type 1 blockade decreases CTGF/CCN2-mediated damage and fibrosis in normal and dystrophic skeletal muscles.

    Science.gov (United States)

    Cabello-Verrugio, Claudio; Morales, María Gabriela; Cabrera, Daniel; Vio, Carlos P; Brandan, Enrique

    2012-04-01

    Connective tissue growth factor (CTGF/CCN-2) is mainly involved in the induction of extracellular matrix (ECM) proteins. The levels of CTGF correlate with the degree and severity of fibrosis in many tissues, including dystrophic skeletal muscle. The CTGF overexpression in tibialis anterior skeletal muscle using an adenoviral vector reproduced many of the features observed in dystrophic muscles including muscle damage and regeneration, fibrotic response and decrease in the skeletal muscle strength. The renin-angiotensin system is involved in the genesis and progression of fibrotic diseases through its main fibrotic components angiotensin-II and its transducer receptor AT-1. The use of AT-1 receptor blockers (ARB) has been shown to decrease fibrosis. In this paper, we show the effect of AT-1 receptor blockade on CTGF-dependent biological activity in skeletal muscle cells as well as the response to CTGF overexpression in normal skeletal muscle. Our results show that in myoblasts ARB decreased CTGF-mediated increase of ECM protein levels, extracellular signal regulated kinases 1/2 (ERK-1/2) phosphorylation and stress fibres formation. In tibialis anterior muscle overexpressing CTGF using an adenovirus, ARB treatment decreased CTGF-mediated increase of ECM molecules, α-SMA and ERK-1/2 phosphorylation levels. Quite remarkable, ARB was able to prevent the loss of contractile force of tibialis anterior muscles overexpressing CTGF. Finally, we show that ARB decreased the levels of fibrotic proteins, CTGF and ERK-1/2 phosphorylation augmented in a dystrophic skeletal muscle from mdx mice. We propose that ARB is a novel pharmacological tool that can be used to decrease the fibrosis induced by CTGF in skeletal muscle associated with muscular dystrophies.

  16. Involvement of PPAR-γ in the neuroprotective and anti-inflammatory effects of angiotensin type 1 receptor inhibition: effects of the receptor antagonist telmisartan and receptor deletion in a mouse MPTP model of Parkinson's disease

    Science.gov (United States)

    2012-01-01

    Background Several recent studies have shown that angiotensin type 1 receptor (AT1) antagonists such as candesartan inhibit the microglial inflammatory response and dopaminergic cell loss in animal models of Parkinson's disease. However, the mechanisms involved in the neuroprotective and anti-inflammatory effects of AT1 blockers in the brain have not been clarified. A number of studies have reported that AT1 blockers activate peroxisome proliferator-activated receptor gamma (PPAR γ). PPAR-γ activation inhibits inflammation, and may be responsible for neuroprotective effects, independently of AT1 blocking actions. Methods We have investigated whether oral treatment with telmisartan (the most potent PPAR-γ activator among AT1 blockers) provides neuroprotection against dopaminergic cell death and neuroinflammation, and the possible role of PPAR-γ activation in any such neuroprotection. We used a mouse model of parkinsonism induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and co-administration of the PPAR-γ antagonist GW9662 to study the role of PPAR-γ activation. In addition, we used AT1a-null mice lesioned with MPTP to study whether deletion of AT1 in the absence of any pharmacological effect of AT1 blockers provides neuroprotection, and investigated whether PPAR-γ activation may also be involved in any such effect of AT1 deletion by co-administration of the PPAR-γ antagonist GW9662. Results We observed that telmisartan protects mouse dopaminergic neurons and inhibits the microglial response induced by administration of MPTP. The protective effects of telmisartan on dopaminergic cell death and microglial activation were inhibited by co-administration of GW9662. Dopaminergic cell death and microglial activation were significantly lower in AT1a-null mice treated with MPTP than in mice not subjected to AT1a deletion. Interestingly, the protective effects of AT1 deletion were also inhibited by co-administration of GW9662

  17. Involvement of PPAR-γ in the neuroprotective and anti-inflammatory effects of angiotensin type 1 receptor inhibition: effects of the receptor antagonist telmisartan and receptor deletion in a mouse MPTP model of Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Garrido-Gil Pablo

    2012-02-01

    Full Text Available Abstract Background Several recent studies have shown that angiotensin type 1 receptor (AT1 antagonists such as candesartan inhibit the microglial inflammatory response and dopaminergic cell loss in animal models of Parkinson's disease. However, the mechanisms involved in the neuroprotective and anti-inflammatory effects of AT1 blockers in the brain have not been clarified. A number of studies have reported that AT1 blockers activate peroxisome proliferator-activated receptor gamma (PPAR γ. PPAR-γ activation inhibits inflammation, and may be responsible for neuroprotective effects, independently of AT1 blocking actions. Methods We have investigated whether oral treatment with telmisartan (the most potent PPAR-γ activator among AT1 blockers provides neuroprotection against dopaminergic cell death and neuroinflammation, and the possible role of PPAR-γ activation in any such neuroprotection. We used a mouse model of parkinsonism induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP and co-administration of the PPAR-γ antagonist GW9662 to study the role of PPAR-γ activation. In addition, we used AT1a-null mice lesioned with MPTP to study whether deletion of AT1 in the absence of any pharmacological effect of AT1 blockers provides neuroprotection, and investigated whether PPAR-γ activation may also be involved in any such effect of AT1 deletion by co-administration of the PPAR-γ antagonist GW9662. Results We observed that telmisartan protects mouse dopaminergic neurons and inhibits the microglial response induced by administration of MPTP. The protective effects of telmisartan on dopaminergic cell death and microglial activation were inhibited by co-administration of GW9662. Dopaminergic cell death and microglial activation were significantly lower in AT1a-null mice treated with MPTP than in mice not subjected to AT1a deletion. Interestingly, the protective effects of AT1 deletion were also inhibited by co

  18. Intrarenal renin-angiotensin system modulates glomerular angiotensin receptors in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Wilkes, B.M.; Pion, I.; Sollott, S.; Michaels, S.; Kiesel, G. (North Shore Univ. Hospital and Cornell Univ. Medical College, Manhasset, NY (USA))

    1988-03-01

    The aim of this study was to test the hypothesis that the intrarenal renin-angiotensin system (RAS) modulates glomerular angiotensin II (ANG II) receptors. In one protocol ANG II receptors were measured 7 days after unilateral denervation of the left kidney in rats. There were 50% more receptors in the glomeruli from denervated compared with innervated kidneys, which was associated with a 63% reduction in left renal vein renin. The differences in ANG II receptors between the left and right kidneys were not longer present when angiotensin-converting enzyme was inhibited with enalapril or when pharmacological amounts of ANG II were infused. In a second protocol, renal cortical renin content was raised in the left kidney by placing a 0.20-mm clip on the left renal artery. At 7 days, glomerular ANG II receptors were reduced by 72.3% in the clipped compared with the contralateral kidneys. The differences in ANG II receptors were no longer present after enalapril treatment. Pharmacological maneuvers that either blocked ANG II formation or increased circulating ANG II resulted in an equal number of ANG II receptors in the right and left kidneys. The data indicate that the intrarenal RAS modulates the density of glomerular ANG II receptors and is a more important receptor modulation than plasma ANG II.

  19. Endogenous hydrogen sulfide is associated with angiotensin II type 1 receptor in a rat model of carbon tetrachloride-induced hepatic fibrosis

    Science.gov (United States)

    FAN, HUI-NING; CHEN, NI-WEI; SHEN, WEI-LIN; ZHAO, XIANG-YUN; ZHANG, JING

    2015-01-01

    The present study aimed to investigate the effects of endogenous hydrogen sulfide (H2S) on the expression levels of angiotensin II type 1 receptor (AGTR1) in a rat model of carbon tetrachloride (CCl4)-induced hepatic fibrosis. A total of 56 Wistar rats were randomly divided into four groups: Normal control group, model group, sodium hydrosulfide (NaHS) group, and DL-propargylglycine (PAG) group. Hepatic fibrosis was induced by CCl4. The rats in the PAG group were intraperitoneally injected with PAG, an inhibitor of cystathionine-γ-lyase (CSE). The rats in the NaHS group were intraperitoneally injected with NaHS. An equal volume of saline solution was intraperitoneally injected into both the control and model groups. All rats were sacrificed at week three or four following treatment. The serum levels of hyaluronidase (HA), laminin protein (LN), procollagen III (PcIII), and collagen IV (cIV) were detected using ELISA. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and albumin (ALB) were detected using an automatic biochemical analyzer. The liver mRNA expression levels of CSE were detected by reverse transcription-quantitative polymerase chain reaction. The liver expression levels of AGTR1 and the plasma expression levels of H2S were detected using western blot analyses. The results indicated that the severity of hepatic fibrosis, the serum expression levels of HA, LN, PcIII, cIV, ALT, and AST, the liver expression levels of CSE and AGTR1, and the plasma expression levels of H2S were significantly higher in the PAG group, as compared with the model group (P<0.05). Conversely, the expression levels of ALB were significantly lower in the PAG group, as compared with the model group. In addition, the severity of hepatic fibrosis, the serum expression levels of HA, LN, PcIII, cIV, ALT, and AST, the liver expression levels of CSE and AGTR1, and the plasma expression levels of H2S were significantly lower in the NaHS group, as compared with

  20. Cerebrovascular angiotensin AT1 receptor regulation in cerebral ischemia

    DEFF Research Database (Denmark)

    Edvinsson, L.

    2008-01-01

    The mechanism behind the positive response to the inhibition of the angiotensin II receptor AT(1) in conjunction with stroke is elusive. Here we demonstrate that cerebrovascular AT(1) receptors show increased expression (upregulation) after cerebral ischemia via enhanced translation. This enhanced...

  1. ACE-inhibition and angiotensin II receptor blockers in chronic heart failure: pathophysiological consideration of the unresolved battle.

    Science.gov (United States)

    Simko, F; Simko, J; Fabryova, M

    2003-05-01

    Reducing the effects of angiotensin II by blockade of AT1-receptors may be superior to inhibition of angiotensin II formation by angiotensin converting enzyme (ACE) inhibitors in chronic heart failure (CHF) patients. However, the results of several trials did not fulfil this expectation. In both ELITE II with symptomatic CHF patients and in OPTIMAAL involving high risk patients after acute myocardial infarction, angiotensin II type I (AT1) receptor blocker (ARB) losartan did not prove to be superior to captopril. There are several potential reasons, why ARBs did not fare better than ACE inhibitors. Although AT1-receptor blockade may block the effects of non-ACE pathways of tissue angiotensin II formation, no clinical evidence is available that a more powerful inhibition of the tissue renin-angiotensin system brings improved survival. The choice of patients for clinical trials of HF therapy is not based on the level of neurohumoral activation. Thus, the more effective attenuation of angiotensin II action with ARBs may not bring additional benefits. The potential antiremodeling effect of ARBs through the stimulation of AT2 receptors by angiotensin II could be counterbalanced by a failure of AT1-receptor blockers to enhance bradykinin, nitric oxide and prostacyclin formation with antigrowth properties. Although ACE-inhibitors seem to have slightly better results at present than AT1 blockers in the battle on heart failure patient, future trials will decide which is the definitive winner.

  2. Aldosterone synthase C-344T, angiotensin II type 1 receptor A1166C and 11- hydroxysteroid dehydrogenase G534A gene polymorphisms and essential hypertension in the population of Odisha, India

    Indian Academy of Sciences (India)

    Manisha Patnaik; Pallabi Pati; Surendra N. Swain; Manoj K. Mohapatra; Bhagirathi Dwibedi; Shantanu K. Kar; Manoranjan Ranjit

    2014-12-01

    Essential hypertension which accounts 90–95% of the total hypertension cases is affected by both genetic and environmental factors. This study was undertaken to investigate the association of aldosterone synthase C-344T, angiotensin II type I receptor A1166C and 11- hydroxysteroid dehydrogenase type 2 G534A polymorphisms with essential hypertension in the population of Odisha, India. A total of 246 hypertensive subjects (males, 159; females, 87) and 274 normal healthy individuals (males, 158; females, 116) were enrolled in this study based on the inclusion and exclusion criteria. Analysis of genetic and biochemical data revealed that in this population the CT and TT genotypes of aldosterone synthase C-344T polymorphism, frequency of alcohol consumption and aldosterone levels were significantly high among the total as well as male hypertensives, while the AC and CC genotypes of angiotensin II type I receptor A1166C polymorphism were significantly high among the total as well as female hypertensives. High density lipoprotein levels were higher in male hypertensives.

  3. Aldosterone synthase C-344T, angiotensin II type 1 receptor A1166C and 11- hydroxysteroid dehydrogenase G534A gene polymorphisms and essential hypertension in the population of Odisha, India

    Indian Academy of Sciences (India)

    Manisha Patnaik; Pallabi Pati; Surendra N. Swain; Manoj K. Mohapatra; Bhagirathi Dwibedi; Shantanu K. Kar; Manoranjan Ranjit

    2015-06-01

    Essential hypertension which accounts 90–95% of the total hypertension cases is affected by both genetic and environmental factors. This study was undertaken to investigate the association of aldosterone synthase C-344T, angiotensin II type I receptor A1166C and 11- hydroxysteroid dehydrogenase type 2 G534A polymorphisms with essential hypertension in the population of Odisha, India. A total of 246 hypertensive subjects (males, 159; females, 87) and 274 normal healthy individuals (males, 158; females, 116) were enrolled in this study based on the inclusion and exclusion criteria. Analysis of genetic and biochemical data revealed that in this population the CT and TT genotypes of aldosterone synthase C-344T polymorphism, frequency of alcohol consumption and aldosterone levels were significantly high among the total as well as male hypertensives, while the AC and CC genotypes of angiotensin II type I receptor A1166C polymorphism were significantly high among the total as well as female hypertensives. High density lipoprotein levels were higher in male hypertensives.

  4. Functional interactions between 7TM receptors in the renin-angiotensin system--dimerization or crosstalk?

    DEFF Research Database (Denmark)

    Lyngsø, Christina; Erikstrup, Niels; Hansen, Jakob L

    2008-01-01

    . The importance of the RAS is clearly emphasised by the widespread use of drugs targeting this system in clinical practice. These include, renin inhibitors, angiotensin II receptor type I blockers, and inhibitors of the angiotensin converting enzyme. Some of the important effectors within the system are 7......The Renin-Angiotensin System (RAS) is important for the regulation of cardiovascular physiology, where it controls blood pressure, and salt- and water homeostasis. Dysregulation of RAS can lead to severe diseases including hypertension, diabetic nephropathy, and cardiac arrhythmia, and -failure...... be important for receptor function, and in the development of cardiovascular diseases. This is very significant, since "dimers" may provide pharmacologists with novel targets for improved drug therapy. However, we know that 7TM receptors can mediate signals as monomeric units, and so far it has been very...

  5. Differential clinical profile of candesartan compared to other angiotensin receptor blockers

    Directory of Open Access Journals (Sweden)

    Zimlichman R

    2011-12-01

    Full Text Available Relu Cernes1,2, Margarita Mashavi1,3, Reuven Zimlichman1,31The Brunner Institute for Cardiovascular Research, Wolfson Medical Center and Tel Aviv University, Tel Aviv, Israel; 2Department of Nephrology, Wolfson Medical Center, Holon, Israel; 3Department of Medicine, Wolfson Medical Center, Holon, IsraelAbstract: The advantages of blood pressure (BP control on the risks of heart failure and stroke are well established. The renin-angiotensin system plays an important role in volume homeostasis and BP regulation and is a target for several groups of antihypertensive drugs. Angiotensin II receptor blockers represent a major class of antihypertensive compounds. Candesartan cilexetil is an angiotensin II type 1 (AT[1] receptor antagonist (angiotensin receptor blocker [ARB] that inhibits the actions of angiotensin II on the renin-angiotensin-aldosterone system. Oral candesartan 8–32 mg once daily is recommended for the treatment of adult patients with hypertension. Clinical trials have demonstrated that candesartan cilexetil is an effective agent in reducing the risk of cardiovascular mortality, stroke, heart failure, arterial stiffness, renal failure, retinopathy, and migraine in different populations of adult patients including patients with coexisting type 2 diabetes, metabolic syndrome, or kidney impairment. Clinical evidence confirmed that candesartan cilexetil provides better antihypertensive efficacy than losartan and is at least as effective as telmisartan and valsartan. Candesartan cilexetil, one of the current market leaders in BP treatment, is a highly selective compound with high potency, a long duration of action, and a tolerability profile similar to placebo. The most important and recent data from clinical trials regarding candesartan cilexetil will be reviewed in this article.Keywords: angiotensin receptor blockers, candesartan, candesartan cilexetil, clinical trials, efficacy studies, safety, blood pressure

  6. Construction of a yeast-based signaling biosensor for human angiotensin II type 1 receptor via functional coupling between Asn295-mutated receptor and Gpa1/Gi3 chimeric Gα.

    Science.gov (United States)

    Nakamura, Yasuyuki; Ishii, Jun; Kondo, Akihiko

    2014-11-01

    Angiotensin II (Ang II) type 1 receptor (AGTR1) is a G-protein-coupled receptor (GPCR). Its natural ligand, Ang II, is an important effector molecule controlling blood pressure and volume in the cardiovascular system, and is consequently involved in various diseases such as hypertension and heart failure. Thus, the signaling mediator, AGTR1, is a significant molecular target in medicinal and therapeutic fields. Yeast is a useful organism for sensing GPCR signaling because it provides a simplified version of the complicated machinery used by mammalian cells for signal transduction. Although yeast cells can successfully transmit a signal through a variety of human GPCRs expressed in the cell membrane, there have been no reports of the functional activation of AGTR1-mediated signaling in yeast cells. In the present study, we introduced a single mutation into human AGTR1 and used yeast-human chimeric Gα to exert the functional activation of AGTR1 in yeast cells. The engineered yeast cells expressing AGTR1 mutated at Asn295 and the chimeric Gα successfully transmitted the signal inside the yeast cells in response to Ang II peptide and its analogs (Ang III and Ang IV peptides) added to the assay medium. Further, we demonstrated that the autocrine Ang II peptide and its analog, produced and secreted by the engineered yeast cells, could by themselves promote AGTR1-mediated signaling. This means that screening for agonistic peptides with various sequences from a self-produced genetic library would be a viable strategy. Thus, the constructed yeast biosensor, integrating an Asn295-mutated AGTR1 receptor, will be valuable in the design of drugs to treat AGTR1-related diseases. © 2014 Wiley Periodicals, Inc.

  7. Proteinuria, a modifiable risk factor: angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs).

    Science.gov (United States)

    Dykeman-Sharpe, Jennifer

    2003-01-01

    Microalbuminuria and proteinuria have been determined to be modifiable risk factors for the progression of chronic kidney disease as well as risk factors for cardiovascular events. Angiotensin converting enzyme inhibitors and angiotensin II receptor blockers have been demonstrated to decrease proteinuria at all stages and slow the progression of renal disease. Proteinuria can be used as a marker of successful treatment in patients with chronic kidney disease in combination with other established targets. This article discusses the various diagnostic tests used for the detection of microalbuminuria and proteinuria and appropriate pharmaceutical treatment.

  8. Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) and lactation: an update.

    Science.gov (United States)

    Shannon, M E; Malecha, S E; Cha, A J

    2000-05-01

    Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are commonly used for the treatment of hypertension. ACEIs have been promoted as first-line therapy for selected patients with chronic hypertension and for the prevention of diabetic nephropathy, thus creating the potential for frequent ACEI exposure among women of childbearing age. ARBs are the most recent addition to the available options for antihypertensive agents. This review specifically focuses on the most up-to-date information regarding these newer antihypertensives with regard to lactation.

  9. Renoprotective effect of combining angiotensinreceptor blockers and statins in diabetic rats

    Institute of Scientific and Technical Information of China (English)

    GAO Ping; JIA Ru-han; YANG Ding-ping; LIU Hong-yan; SONG En-feng; CHU Gui-li; DING Guo-hua

    2005-01-01

    @@ Recent studies suggest that treatment with angiotensintype 1 (AT1) receptor blockers and lipid lowering agents, namely the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statins may have beneficial effects on renal function independent of lowering actions on blood pressure and cholesterol.

  10. INHIBITION OF KIDNEY DISORDERS IN CARDIOVASCULAR DISEASES: THE ROLE OF ANGIOTENSIN II RECEPTOR BLOCKERS

    Directory of Open Access Journals (Sweden)

    V. V. Fomin

    2008-01-01

    Full Text Available Mechanisms of renal disorders in cardiovascular diseases are presented. The main of these mechanisms is an endothelium dysfunction. It is related with some factors: arterial hypertension, insulin resistance syndrome, diabetes type 2, dyslipidemia, obesity. Approaches to prevention of kidney disorder and cardiovascular complications are discussed with focus on usage of angiotensin II receptor blockers.

  11. Angiotensin receptor agonistic autoantibodies and hypertension: preeclampsia and beyond.

    Science.gov (United States)

    Xia, Yang; Kellems, Rodney E

    2013-06-21

    Hypertensive disorders are life-threatening diseases with high morbidity and mortality, affecting billions of individuals worldwide. A multitude of underlying conditions may contribute to hypertension, thus the need for a plethora of treatment options to identify the approach that best meets the needs of individual patients. A growing body of evidence indicates that (1) autoantibodies that bind to and activate the major angiotensin II type I (AT₁) receptor exist in the circulation of patients with hypertensive disorders, (2) these autoantibodies contribute to disease pathophysiology, (3) antibody titers correlate to the severity of the disease, and (4) efforts to block or remove these pathogenic autoantibodies have therapeutic potential. These autoantibodies, termed AT₁ agonistic autoantibodies have been extensively characterized in preeclampsia, a life-threatening hypertensive condition of pregnancy. As reviewed here, these autoantibodies cause symptoms of preeclampsia when injected into pregnant mice. Somewhat surprisingly, these auto antibodies also appear in 3 animal models of preeclampsia. However, the occurrence of AT₁ agonistic autoantibodies is not restricted to pregnancy. These autoantibodies are prevalent among kidney transplant recipients who develop severe transplant rejection and malignant hypertension during the first week after transplantation. AT₁ agonistic autoantibodies are also highly abundant among a group of patients with essential hypertension that are refractory to standard therapy. More recently these autoantibodies have been seen in patients with the autoimmune disease, systemic sclerosis. These 3 examples extend the clinical impact of AT₁ agonistic autoantibodies beyond pregnancy. Research reviewed here raises the intriguing possibility that preeclampsia and other hypertensive conditions are autoimmune diseases characterized by the presence of pathogenic autoantibodies that activate the major angiotensin receptor, AT₁. These

  12. G-protein coupled receptors of the renin-angiotensin system: new targets against breast cancer?

    OpenAIRE

    Rodrigues-Ferreira, Sylvie; Nahmias, Clara

    2015-01-01

    G-protein coupled receptors (GPCRs) constitute the largest family of membrane receptors, with high potential for drug discovery. These receptors can be activated by a panel of different ligands including ions, hormones, small molecules, and vasoactive peptides. Among those, angiotensins [angiotensin II (AngII) and angiotensin 1–7] are the major biologically active products of the classical and alternative renin-angiotensin system (RAS). These peptides bind and activate three different subtype...

  13. The telmisartan renoprotective study from incipient nephropathy to overt nephropathy--rationale, study design, treatment plan and baseline characteristics of the incipient to overt: angiotensin II receptor blocker, telmisartan, Investigation on Type 2 Diabetic Nephropathy (INNOVATION) Study.

    Science.gov (United States)

    Makino, H; Haneda, M; Babazono, T; Moriya, T; Ito, S; Iwamoto, Y; Kawamori, R; Takeuchi, M; Katayama, S

    2005-01-01

    We planned the INNOVATION study to determine whether telmisartan, an angiotensin-2-receptor blocker, delays the progression of renal disease from incipient nephropathy to overt nephropathy in hypertensive or normotensive Japanese patients with type 2 diabetes mellitus. The INNOVATION study is a randomized, double-blind, placebo-controlled trial. Eligible patients must have incipient nephropathy (defined as a urinary albumin to creatinine ratio of 100-300 mg/g creatinine) and a serum creatinine concentration of 300 mg/g creatinine and 30% higher than the baseline on at least two consecutive visits). A total of 1855 patients have been enrolled from 160 study centres. In 527 randomized patients (28.4% of the enrolled patients), mean (SD) urinary albumin to creatinine ratio and serum creatinine concentration at baseline were 173.3 (47.2) mg/g creatinine and 0.78 (0.19) mg/dl. Sixty-eight per cent of the patients had hypertension at baseline. Mean (SD) systolic and diastolic blood pressures at baseline were 137.1 (14.6) and 77.5 (10.3) mmHg. The INNOVATION study will determine whether telmisartan, an angiotensin II receptor blocker, provides clinical benefits in hypertensive or normotensive patients with diabetes mellitus and diabetic nephropathy.

  14. No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

    DEFF Research Database (Denmark)

    Estrup, T M; Paulson, O B; Strandgaard, S

    2001-01-01

    Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral cir...

  15. No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

    DEFF Research Database (Denmark)

    Estrup, T M; Paulson, O B; Strandgaard, S

    2001-01-01

    Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral...

  16. Angiotensin type 1a receptors in the forebrain subfornical organ facilitate leptin-induced weight loss through brown adipose tissue thermogenesis

    Directory of Open Access Journals (Sweden)

    Colin N. Young

    2015-04-01

    Conclusions: These data identify a novel interaction between angiotensin-II and leptin in the control of BAT thermogenesis and body weight, and highlight a previously unrecognized role for the forebrain SFO in metabolic regulation.

  17. Angiotensin receptor blockers & endothelial dysfunction: Possible correlation & therapeutic implications

    Directory of Open Access Journals (Sweden)

    Miroslav Radenkovic

    2016-01-01

    Full Text Available The endothelium is one of the most important constituents of vascular homeostasis, which is achieved through continual and balanced production of different relaxing and contractile factors. When there is a pathological disturbance in release of these products, endothelial dysfunction (ED will probably occur. ED is considered to be the initial step in the development of atherosclerosis. This pathological activation and inadequate functioning of endothelial cells was shown to be to some extent a reversible process, which all together resulted in increased interest in investigation of different beneficial treatment options. To this point, the pharmacological approach, including for example, the use of angiotensin-converting enzyme inhibitors or statins, was clearly shown to be effective in the improvement of ED. One of many critical issues underlying ED represents instability in the balance between nitric oxide and angiotensin II (Ang II production. Considering that Ang II was confirmed to be important for the development of ED, the aim of this review article was to summarize the findings of up to date clinical studies associated with therapeutic application of angiotensin receptor blockers and improvement in ED. In addition, it was of interest to review the pleiotropic actions of angiotensin receptor blockers linked to the improvement of ED. The prospective, randomized, double-blind, placebo or active-controlled clinical trials were identified and selected for the final evaluation.

  18. Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system

    Energy Technology Data Exchange (ETDEWEB)

    Camelo, J.S. Jr. [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Martins, A.R. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Instituto de Ciências Biológicas, Universidade Federal do Triângulo Mineiro, Uberaba, MG (Brazil); Rosa, E. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Ramos, S.G. [Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SPBrasil (Brazil); Hehre, D.; Bancalari, E.; Suguihara, C. [Department of Pediatrics, Division of Neonatology, Neonatal Developmental Biology Laboratory, University of Miami Miller School of Medicine, Miami, FL (United States)

    2012-02-10

    The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 ± 0.9 days; 2369 ± 491 g) were randomly assigned to receive saline (placebo, P) or the AT{sub 1} receptor (AT{sub 1}-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO{sub 2} = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT{sub 1}-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT{sub 1}-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT{sub 1}-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT{sub 1}-R staining, but C animals showed weak iNOS and AT{sub 1}-R staining. Macrophages of L and P animals showed moderate and weak AT{sub 2}-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT{sub 1}-R blockade. We suggest that AT{sub 1}-R blockade might act through AT{sub 2}-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.

  19. Angiotensin Receptor Blockers: Cardiovascular Protection in the Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Prakash C Deedwania

    2006-03-01

    Full Text Available It is well recognised that the metabolic syndrome, a constellation of risk factors including obesity, hypertension, insulin resistance and dyslipidaemia, is associated with an increased risk of cardiovascular complications and the development of Type 2 diabetes. Consequently, timely identification and management of all components of the metabolic syndrome is warranted. In particular, guidelines have emphasised the importance of targeting elevated blood pressure (BP and dyslipidaemia as a method of reducing global cardiovascular risk.Findings from the Valsartan Antihypertensive Long-term Use Evaluation (VALUE trial show that the angiotensin receptor blocker, valsartan, reduces cardiovascular events and the development of Type 2 diabetes in high-risk individuals. This profile is being further explored in the ongoing Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR trial.Given the potential advantages to patients and physicians of tackling more than one of the components of the metabolic syndrome, antihypertensive agents such as valsartan would appear to be an important addition to the management of vulnerable patients at high risk of cardiovascular events.

  20. Effect of active immunization against angiotensin II type 1 (AT1) receptor on hypertension & arterial remodelling in spontaneously hypertensive rats (SHR)

    OpenAIRE

    Liu-Dong Li; Miao Tian; Yu-Hua Liao; Zi-Hua Zhou; Fen Wei; Feng Zhu; Min Wang; Bin Wang; Yu-Miao Wei

    2014-01-01

    Background & objectives: a0 ngiotensin II receptor type 1 (AT1) is known to be involved in the pathogenesis of hypertension. t0 his study was undertaken to explore the effect of active immunization against AT1 receptor on blood pressure and small artery remodelling in spontaneously hypertensive rat (SHR). Methods: Male SHR and Wistar rats aged two months were actively immunized with different peptides (ATR12185ͱͲATR10014 and ATR12181) corresponding to particular sequences of rat AT1 recep...

  1. Activation of the Cardiac Renin-Angiotensin System in High Oxygen-Exposed Newborn Rats: Angiotensin Receptor Blockade Prevents the Developmental Programming of Cardiac Dysfunction.

    Science.gov (United States)

    Bertagnolli, Mariane; Dios, Anne; Béland-Bonenfant, Sarah; Gascon, Gabrielle; Sutherland, Megan; Lukaszewski, Marie-Amélie; Cloutier, Anik; Paradis, Pierre; Schiffrin, Ernesto L; Nuyt, Anne Monique

    2016-04-01

    Newborn rats exposed to high oxygen (O2), mimicking preterm birth-related neonatal stress, develop later in life cardiac hypertrophy, dysfunction, fibrosis, and activation of the renin-angiotensin system. Cardiac renin-angiotensin system activation in O2-exposed adult rats is characterized by an imbalance in angiotensin (Ang) receptors type 1/2 (AT1/2), with prevailing AT1 expression. To study the role of renin-angiotensin system in the developmental programming of cardiac dysfunction, we assessed Ang receptor expression during neonatal high O2 exposure and whether AT1 receptor blockade prevents cardiac alterations in early adulthood. Sprague-Dawley newborn rats were kept with their mother in 80% O2 or room air (control) from days 3 to 10 (P3-P10) of life. Losartan or water was administered by gavage from P8 to P10 (n=9/group). Rats were studied at P3 (before O2 exposure), P5, P10 (end of O2), and P28. Losartan treatment had no impact on growth or kidney development. AT1 and Ang type 2 receptors were upregulated in the left ventricle by high O2 exposure (P5 and P10), which was prevented by Losartan treatment at P10. Losartan prevented the cardiac AT1/2 imbalance at P28. Losartan decreased cardiac hypertrophy and fibrosis and improved left ventricle fraction of shortening in P28 O2-exposed rats, which was associated with decreased oxidation of calcium/calmodulin-dependent protein kinase II, inhibition of the transforming growth factor-β/SMAD3 pathway, and upregulation of cardiac angiotensin-converting enzyme 2. In conclusion, short-term Ang II blockade during neonatal high O2 prevents the development of cardiac alterations later in life in rats. These findings highlight the key role of neonatal renin-angiotensin system activation in the developmental programming of cardiac dysfunction induced by deleterious neonatal conditions.

  2. Clinical Evidence for the Cardiovascular Benefits of Angiotensin Receptor Blockers

    Directory of Open Access Journals (Sweden)

    Georg Nickenig

    2006-03-01

    Full Text Available Targeting the renin-angiotensin-aldosterone system (RAAS, specifically the effector peptide angiotensin II (Ang II, represents a major opportunity for slowing the progression of cardiovascular disease (CVD and, in turn, reducing the risk of morbidity and mortality. Inhibition of angiotensin-converting enzyme (ACE and selective blockade of Ang II AT1 receptors are two approaches through which the pathophysiological effects of Ang II can be targeted. Numerous clinical studies have established the benefits of ACE inhibitors P, (ACE-Is in lessening the morbidity and mortality burden of CVD. There are, however, tolerability concerns associated with ACE-Is, such as angioedema and dry cough. By blocking Ang II at the AT1 receptor level, Ang II receptor blockers (ARBs provide a more specific and complete blockade of the deleterious effects of Ang II and tend to have more favourable tolerability. A number of clinical trials have shown that ARBs are not only associated with positive outcomes across the CVD continuum but may also have a role in the prevention or delay of diabetes (a major cardiovascular risk factor. Ongoing trials are aiming to define the place of such agents in lessening morbidity and mortality from CVD.

  3. The role of angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists in the management of diabetic complications.

    Science.gov (United States)

    Podar, Toomas; Tuomilehto, Jaakko

    2002-01-01

    Evidence suggests that ACE inhibitors can be advantageous for prevention and halting progression of both micro- and macrovascular complications in patients with diabetes mellitus. ACE inhibitors are useful antihypertensive agents in both type 1 and type 2 diabetes; however, ACE inhibitor therapy often needs to be supplemented with calcium channel antagonists, beta-blockers or diuretics to achieve good blood pressure control. ACE inhibitors are also indicated in non-hypertensive patients with type 1 and type 2 diabetes who have micro- or macroalbuminuria. The effect of ACE inhibitors in halting the development and progression of retinopathy and, potentially, neuropathy needs further proof in large-scale studies. More recently, angiotensin II receptor antagonists are emerging as drugs with the potential to be successfully included in the management of diabetic complications, especially when ACE inhibitors are not suitable because of adverse effects.

  4. Effects of Angiotensin Converting Enzyme Inhibitors and Angiotensin Receptor Blockers in Contrast-Induced Nephropathy

    Directory of Open Access Journals (Sweden)

    Letian Zhou

    2014-03-01

    Full Text Available Contrast-induced nephropathy (CIN is considered the third leading cause of iatrogenic acute kidney injury in high-risk patients undergoing radiographic procedures. The main mechanism leading to CIN is medullary hypoxia due to decreased renal blood flow, secondary to renal artery vasoconstriction and direct tubular toxicity by contrast medium. Furthermore, experimental data suggests that an activated renin-angiotensin-aldosterone system (RAAS plays a role in the pathophysiology of CIN. However, the role of RAAS blockers, including angiotensin-converting enzyme inhibitors (ACEIs and angiotensin receptor blockers (ARBs in CIN is controversial. They have been reported to be effective in the prevention of CIN in previous studies, but some studies have concluded that they were associated with an increased risk of CIN, especially in patients with pre-existing renal impairment. In summary, there is no solid data to link ACE inhibitors and ARB to CIN, and larger randomised controlled trials are necessary to further investigate their role in the development of CIN. In this review, we discuss the pathophysiology of CIN, the role of RAAS on the development of CIN, and the effect of RAAS blockers on CIN.

  5. Angiotensin II Type 1 receptor (AT1) signaling in astrocytes regulates synaptic degeneration-induced leukocyte entry to the central nervous system

    DEFF Research Database (Denmark)

    Füchtbauer, L; Groth-Rasmussen, Maria; Holm, Thomas Hellesøe

    2011-01-01

    in the dentate gyrus following axonal transection was totally abrogated in GFAP-IκBα-dn mice. Whereas angiotensin II was upregulated in microglia and astrocytes in the dentate gyrus post-lesion, AT1 was exclusively expressed on astrocytes. Blocking AT1 with Candesartan led to significant increase in numbers...

  6. The effect of angiotensin receptor blockers on C-reactive protein and other circulating inflammatory indices in man

    Directory of Open Access Journals (Sweden)

    Alessandra Del Fiorentino

    2009-02-01

    Full Text Available Alessandra Del Fiorentino, Silvana Cianchetti, Alessandro Celi, Giulia Dell’Omo, Roberto PedrinelliDipartimento Cardio Toracico e Vascolare, Università di Pisa, ItalyAbstract: Anti-inflammatory properties may contribute to the pharmacological effects of angiotensin II receptor blockers (ARBs, a leading therapeutic class in the management of hypertension and related cardiovascular and renal diseases. That possibility, supported by consistent evidence from in-vitro and animal studies showing pro-inflammatory properties of angiotensin II, has been evaluated clinically by measuring the effect of ARBs on C-reactive protein and other circulating indices of inflammation (e-selectin, adhesion molecules, interleukin-6, tissue necrosis factor-alpha, monocyte chemoattractant protein-1 of potential clinical relevance, a body of evidence that this paper aims to review.Keywords: renin–angiotensin system, angiotensin II type 1 receptor blockers, vascular inflammation, C-reactive protein, circulating inflammatory markers

  7. Reappraisal of role of angiotensin receptor blockers in cardiovascular protection

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    Ram CV

    2011-05-01

    Full Text Available C Venkata S RamTexas Blood Pressure Institute, Clinical Research Institute of Dallas Nephrology Associates; and Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USAAbstract: Angiotensin-converting enzyme inhibitors (ACEIs and angiotensin receptor blockers (ARBs have shown cardioprotective and renoprotective properties. These agents are recommended as first-line therapy for the treatment of hypertension and the reduction of cardiovascular risk. Early studies pointed to the cardioprotective and renoprotective effects of ARBs in high-risk patients. The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET established the clinical equivalence of the cardioprotective and renoprotective effects of telmisartan and ramipril, but did not find an added benefit of the combination over ramipril alone. Similar findings were observed in the Telmisartan Randomized AssessmeNt Study in aCE INtolerant subjects with cardiovascular Disease (TRANSCEND trial conducted in ACEI-intolerant patients. In ONTARGET, telmisartan had a better tolerability profile with similar renoprotective properties compared with ramipril, suggesting a potential clinical benefit over ramipril. The recently completed Olmesartan Reducing Incidence of Endstage Renal Disease in Diabetic Nephropathy Trial (ORIENT and Olmesartan and Calcium Antagonists Randomized (OSCAR studies will further define the role of ARBs in cardioprotection and renoprotection for high-risk patients.Keywords: angiotensin receptor blockers, hypertension, outcomes, clinical trials

  8. O polimorfismo A1166C do receptor tipo 1 da angiotensina II no infarto agudo do miocárdio The A1166C polymorphism of the angiotensin II type-1 receptor in acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Messias Antônio de Araújo

    2004-11-01

    Full Text Available RESUMO OBJETIVO:Avaliar a associação do polimorfismo A1166C do gene do receptor AT1 da angiotensina II (AT1R com o infarto agudo do miocárdio e a severidade da doença arterial coronariana. MÉTODOS: Estudo prospectivo, transversal de 110 pacientes com infarto agudo do miocárdio submetidos à angiografia coronariana com lesão significante (> 50% avaliada por três critérios de severidade: número de vasos lesados, morfologia da placa aterosclerótica e escore de risco coronariano. Sem lesões coronarianas 104 indivíduos controles. O polimorfismo A1166C do gene do AT1R foi determinado pela reação em cadeia da polimerase no DNA dos leucócitos do sangue periférico. Os fatores de risco coronariano clássicos foram analisados em todos os indivíduos. RESULTADOS: Na estratificação dos genótipos em relação aos fatores de risco apenas o tabagismo teve predominância nos heterozigotos AC (p = 0,02. A freqüência dos genótipos nos pacientes infartados foi de AA = 54,5%; AC = 35,5% e CC = 10%, sendo similar e não significativa em relação aos controles (p = 0,83. Não houve aumento do risco de infarto agudo do miocárdio nas comparações dos genótipos CC vs AA (OR = 1,35; IC-95% = 0,50 - 3,59, AC vs AA (OR = 1,03; IC-95% = 0,58 - 1,84 e AA+AC vs AA (OR = 1,33; IC-95% = 0,51 - 3,45. Nenhum dos critérios de severidade teve associação significativa com os genótipos. CONCLUSÃO: Os nossos resultados indicam não haver associação do polimorfismo A1166C do AT1R com o infarto agudo do miocárdio e nem com a severidade da doença arterial coronariana segundo nossos resultados.OBJECTIVE: To assess the association of the A1166C polymorphism of the angiotensin II type-1 receptor (AT1R gene with acute myocardial infarction and also with the severity of coronary artery disease. METHODS: A prospective, cross-sectional study was carried out with 110 patients with acute myocardial infarction, who, on coronary angiography, had significant

  9. Expression of AngiotensinReceptors in Aldosterone-producing Adenoma of the Adrenal Gland and Their Clinical Significance

    Institute of Scientific and Technical Information of China (English)

    吴准; 倪栋; 闫永吉; 李俊; 王保军; 欧阳金枝; 张国玺; 马鑫; 李宏召; 张旭

    2010-01-01

    The expression of angiotensintype 1 receptor (AT1R) and angiotensintype 2 receptor (AT2R) in aldosterone-producing adenoma (APA) of the adrenal gland was detected, and their relationship with clinical indexes of APA was analyzed. The mRNA expression of AT1R and AT2R in 50 cases of APA and tissues adjacent to tumors and 12 cases of normal adrenal tissues was detected by using reverse transcriptase polymerase chain reaction (RT-PCR). The expression of AT1R and AT2R proteins in paraffin-embedded slices o...

  10. Renal graft failure after addition of an angiotensin II receptor antagonist to an angiotensin-converting enzyme inhibitor

    DEFF Research Database (Denmark)

    Kamper, Anne-Lise; Nielsen, Arne Høj; Baekgaard, Niels

    2002-01-01

    Combined treatment with an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II (Ang II) receptor blocker (ARB) has been suggested in order to achieve a more complete blockade of the renin-angiotensin-aldosterone system in cardiovascular and renal disease. The present report...... describes a case of acute renal graft dysfunction following the addition of an ARB to existing ACE inhibition. This unmasked an unknown iliac artery stenosis. The case indicates a possible important role of Ang II generated by non-ACE pathways in this situation....

  11. A1166C genetic variation of the angiotensin II type I receptor gene and susceptibility to coronary heart disease: collaborative of 53 studies with 20,435 cases and 23,674 controls.

    Science.gov (United States)

    Xu, Mingqing; Sham, Pak; Ye, Zheng; Lindpaintner, Klaus; He, Lin

    2010-11-01

    Angiotensin II induces vasoconstriction and vascular smooth muscle growth via stimulation of the angiotensin II type I receptor (AGTR1). Some studies have reported an association between a genetic variant (A1166C) in the 3' un-translated region of AGTR1 and increased risk of coronary heart disease (CHD), but other have yielded apparently conflicting results. Literature-based meta-analyses were performed on 48 papers including 53 studies published before June 2008 in relation to the A1166C polymorphism (NCBI, dbSNP: rs5186) of the AGTR1, involving a total of 20,435 CHD cases and 23,674 controls. We also explored potential sources of heterogeneity and conducted appropriate stratified analyses. In a combined analysis, the per-allele odds ratio (OR) for CHD of the A1166C polymorphism was 1.11 (95% confidence interval: 1.03-1.19), but there is an indication of publication bias and heterogeneity among the 53 studies. Sample size and study quality were significant sources of heterogeneity among studies of the A1166C polymorphism with possibly overestimates in studies of smaller sample-size and poor-quality. When the analyses were restricted to 11 larger studies (≥500 cases), and to 8 high-quality studies (quality score: ≥11 points), the summary per-allele odds ratios were 0.992 (95% confidence interval, 0.944-1.042) and 0.990 (95% confidence interval, 0.915-1.072), respectively. An overall weak association between the A1166C polymorphism and CHD is observed but this is likely to be due to publication bias and heterogeneity between studies. There were no significant associations among the larger sample-size and high-quality studies which are less prone to selective publication and have greater power to detect a true association. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  12. The angiotensin II type 1 receptor antagonist telmisartan inhibits cell proliferation and tumor growth of esophageal adenocarcinoma via the AMPKα/mTOR pathway in vitro and in vivo.

    Science.gov (United States)

    Fujihara, Shintaro; Morishita, Asahiro; Ogawa, Kana; Tadokoro, Tomoko; Chiyo, Taiga; Kato, Kiyohito; Kobara, Hideki; Mori, Hirohito; Iwama, Hisakazu; Masaki, Tsutomu

    2017-01-31

    Telmisartan, a widely used antihypertensive drug, is an angiotensin II type 1 (AT1) receptor blocker (ARB). This drug inhibits cancer cell proliferation, but the underlying mechanisms in various cancers, including esophageal cancer, remain unknown. The aim of the present study was to evaluate the effects of telmisartan on human esophageal cancer cell proliferation in vitro and in vivo. We assessed the effects of telmisartan on human esophageal adenocarcinoma (EAC) cells using the cell lines OE19, OE33, and SKGT-4. Telmisartan inhibited the proliferation of these three cell lines via blockade of the G0 to G1 cell cycle transition. This blockade was accompanied by a strong decrease in cyclin D1, cyclin E, and other cell cycle-related proteins. Notably, the AMP-activated protein kinase (AMPK) pathway, a fuel sensor signaling pathway, was enhanced by telmisartan. Compound C, which inhibits the two catalytic subunits of AMPK, enhanced the expression of cyclin E, leading to G0/G1 arrest in human EAC cells. In addition, telmisartan reduced the phosphorylation of epidermal growth factor receptor (p-EGFR) and ERBB2 in vitro. In our in vivo study, intraperitoneal injection of telmisartan led to a 73.2% reduction in tumor growth in mice bearing xenografts derived from OE19 cells. Furthermore, miRNA expression was significantly altered by telmisartan in vitro and in vivo. In conclusion, telmisartan suppressed human EAC cell proliferation and tumor growth by inducing cell cycle arrest via the AMPK/mTOR pathway.

  13. Moderation of dietary sodium potentiates the renal and cardiovascular protective effects of angiotensin receptor blockers

    DEFF Research Database (Denmark)

    Lambers Heerspink, Hiddo J; Holtkamp, Frank A; Parving, Hans-Henrik

    2012-01-01

    Dietary sodium restriction has been shown to enhance the short-term response of blood pressure and albuminuria to angiotensin receptor blockers (ARBs). Whether this also enhances the long-term renal and cardiovascular protective effects of ARBs is unknown. Here we conducted a post-hoc analysis...... of the RENAAL and IDNT trials to test this in patients with type 2 diabetic nephropathy randomized to ARB or non-renin-angiotensin-aldosterone system (non-RAASi)-based antihypertensive therapy. Treatment effects on renal and cardiovascular outcomes were compared in subgroups based on dietary sodium intake...... effects of ARB compared with non-RAASi-based therapy on renal and cardiovascular outcomes were greater in patients with type 2 diabetic nephropathy with lower than higher dietary sodium intake. This underscores the avoidance of excessive sodium intake, particularly in type 2 diabetic patients receiving...

  14. Dual Blockade of the Renin-angiotensin-aldosterone System in Type 2 Diabetic Kidney Disease

    Institute of Scientific and Technical Information of China (English)

    Yan-Huan Feng; Ping Fu

    2016-01-01

    Objective: To examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS) among patients with type 2 diabetic kidney disease.Data Sources: We searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use ofmonotherapy, without applying any language restrictions.Keywords for the searches included "diabetic nephropathy," "chronic kidney disease," "chronic renal insufficiency," "diabetes mellitus," "dual therapy," "combined therapy,""dual blockade," "renin-angiotensin system," "angiotensin-converting enzyme inhibitor," "angiotensin-receptor blocker," "aldosterone blockade," "selective aldosterone blockade," "renin inhibitor," "direct renin inhibitor," "mineralocorticoid receptor blocker," etc.Study Selection: The selected articles were carefully reviewed.We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus.Results: Combination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensinreceptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension.However, existing literature has presented mixed results, in particular, related to patient safety.In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons.Conclusions: Despite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility.Further trials are warranted to study the combination therapy as an evidence-based practice.

  15. Dual Blockade of the Renin-angiotensin-aldosterone System in Type 2 Diabetic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Yan-Huan Feng

    2016-01-01

    Full Text Available Objective: To examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS among patients with type 2 diabetic kidney disease. Data Sources: We searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use of monotherapy, without applying any language restrictions. Keywords for the searches included "diabetic nephropathy," "chronic kidney disease," "chronic renal insufficiency," "diabetes mellitus," "dual therapy," "combined therapy," "dual blockade," "renin-angiotensin system," "angiotensin-converting enzyme inhibitor," "angiotensin-receptor blocker," "aldosterone blockade," "selective aldosterone blockade," "renin inhibitor," "direct renin inhibitor," "mineralocorticoid receptor blocker," etc. Study Selection: The selected articles were carefully reviewed. We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus. Results: Combination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensin II receptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension. However, existing literature has presented mixed results, in particular, related to patient safety. In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons. Conclusions: Despite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility. Further trials are warranted to study the combination therapy as an

  16. Hyperkalemia associated with use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers.

    Science.gov (United States)

    Raebel, Marsha A

    2012-06-01

    The aims of this article are to review the current understanding of hyperkalemia associated with angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) therapy. This includes reviewing the pathophysiology of how these agents affect potassium handling within the kidney, risk factors for developing hyperkalemia, incidence, clinical signs and symptoms, and providing a practical approach to treatment of the patient who is either at risk of, or experiencing, hyperkalemia. ACEi and ARB are effective therapeutic agents used in a variety of clinical scenarios. However, related to their effects on the renin-angiotensin-aldosterone system, their use can be associated with hyperkalemia, particularly in patients who have chronic renal insufficiency. Published incidence estimates of hyperkalemia associated with ACEi or ARB vary, but up to 10% of patients may experience at least mild hyperkalemia. Important considerations when initiating ACEi or ARB therapy include obtaining an estimate of glomerular filtration rate and a baseline serum potassium concentration, as well as assessing whether the patient has excessive potassium intake from diet, supplements, or drugs that can also increase serum potassium. Serum potassium monitoring shortly after initiation of therapy can assist in preventing hyperkalemia. If hyperkalemia does develop, prompt recognition of cardiac dysrhythmias and effective treatment to antagonize the cardiac effects of potassium, redistribute potassium into cells, and remove excess potassium from the body is important.Understanding the mechanism of action of ACEi and ARB coupled with judicious drug use and clinical vigilance can minimize the risk to the patient of developing hyperkalemia. Should hyperkalemia occur, prompt recognition and management can optimize clinical outcome.

  17. Safety and efficacy of angiotensin converting enzyme inhibitors and angiotensin receptor blockers in chronic allograft injury

    Directory of Open Access Journals (Sweden)

    P R Shah

    2011-01-01

    Full Text Available Angiotensin II plays a crucial role in the development of chronic allograft injury (CAI. Clinical experience with angiotensin converting enzyme inhibitor (ACEI and angiotensin receptor blockade (ARBS in CAI has unfortunately been limited. We carried out a prospective one year single center case controlled study to analyze the effect of ACEI /ARBS on the progression of CAI and in decreasing proteinuria. One hundred patients with CAI were evaluated. Of the 100 patients, 50 were selected to receive ACEI/ ARBS (group 1 and 50 managed without ACEI/ARBS (group 2. Their remaining management was similar in both the groups. Patients with hyperkalemia, history of allergic reactions, ACEI/ARBS intake and pregnancy were excluded. Average time for development of CAI was 19.6 ± 12.7 months in group 1 vs. 20.8 ± 12.8 in group 2. In group 1, mean systolic/diastolic BP was 136/82 mmHg at the time of establishment of CAI and 124/76 mmHg at the end of one year, and in group 2, it was 138/86 mmHg vs. 126/80 mmHg, respectively. Mean glomerular filtration rate (GFR was 48.78 ± 13.4 in the former vs. 44.23 ± 8.14 in the latter. ACEI/ARBS administration was associated with stabilization of serum creatinine. GFR was maintained up to one year after CAI. Group 1 had a decrease in proteinuria by 1.41 g/day as compared with group 2 with proteinuria of 0.83 g/day. ACEI/ARBS administration is beneficial in CAI for BP control and significant decrease in proteinuria along with the stabilization of graft function.

  18. Angiotensin II receptor alterations during pregnancy in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.P.; Venuto, R.C.

    1986-07-01

    Despite activation of the renin-angiotensin system during pregnancy, renal and peripheral vascular blood flows increase, and the systemic blood pressure and the pressor response to exogenous angiotensin II (Ang II) fall. Gestational alterations in Ang II receptors could contribute to these changes. Ang II binding parameters were determining utilizing SVI-Ang II in vascular (glomeruli and mesenteric arteries) and nonvascular (adrenal glomerulosa) tissues from 24- to 28-day pregnant rabbits. Comparisons were made utilizing tissues from nonpregnant rabbits. Binding site concentrations (N) and dissociation constants (K/sub d/) were obtained by Scatchard analyses of binding inhibition data. Meclofenamate (M) inhibits prostaglandin synthesis, reduces plasma renin activity, and enhances the pressor response to infused Ang II in pregnant rabbits. Administration of M to pregnant rabbits increased N in glomerular and in mesenteric artery membranes. These data demonstrate that Ang II receptors in glomeruli and mesenteric arteries are down regulated during gestation in rabbits. Elevated endogenous Ang II during pregnancy in rabbits may contribute to the down regulation of vascular Ang II receptors.

  19. Prorenin receptor regulates more than the renin-angiotensin system.

    Science.gov (United States)

    Müller, Dominik N; Binger, Katrina J; Riediger, Fabian

    2012-06-01

    The (pro)renin receptor (PRR) was initially believed to be a contributor to the pathogenesis of cardiovascular diseases via the amplification of renin- or prorenin-induced angiotensin (Ang) formation. However, a recent paradigm shift suggests a new role for PRR, separate from the renin-angiotensin system (RAS), in contributing to cellular homeostasis. Specifically, PRR is thought to be essential for vacuolar H(+) -ATPase (V-ATPase) activity and acts as an adaptor between the V-ATPase and the Wnt signalling pathway. Recent PRR conditional knock-out studies have confirmed this link between V-ATPase and PRR, with deletion resulting in the accumulation of autophagic vacuoles and animal lethality. The molecular mechanism by which PRR contributes to V-ATPase activity, and whether multiple signalling pathways are affected by PRR loss, is currently unknown. Additionally, cleavage by furin at a single site within full-length PRR results in the production of a soluble form of the receptor, which is detectable in plasma. Soluble PRR is hypothesized to bind to specific ligands and receptors and mediate signal transduction pathways. Understanding the physiological function of full-length and soluble PRR will be important for establishing its role in pathology.

  20. Role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the management of atrial fibrillation

    Science.gov (United States)

    Anis, Rafik R

    2009-01-01

    Atrial fibrillation (AF) is the most common clinical arrhythmia, and is difficult to treat. Current treatment strategies are far from optimal. Antiarrhythmic drug therapy to maintain sinus rhythm is limited by inadequate efficacy and potentially serious side effects. New areas of research include targeting the AF substrate and examining whether drugs can produce atrial structural and/or electrophysiological remodelling, and whether this results in a reduction in AF burden. There are two approaches to the treatment of AF. The first approach is cardioversion and treatment with antiarrhythmic drugs to maintain sinus rhythm. The other approach is the use of rate-controlling drugs allowing AF to persist. In both approaches, the use of anticoagulant drugs is recommended. There is an increasing interest in novel therapeutic approaches that target AF-substrate development. Recent trials suggest that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor II blockers (ARBs) may be useful, particularly in patients with left ventricular hypertrophy, hypertension, chronic heart failure and left ventricular dysfunction. While experimental studies have shown that the pathogenic structural and electrical remodelling of the atria are prevented by inhibition of angiotensin II, the clinical potential and mechanisms of this approach are still under active investigation. The present article will discuss information pertaining to the mechanism of action and clinical use of ACEIs and ARBs in AF. It will also review the current data on the use of ACEIs and ARBs in a high-risk group of AF patients (heart failure, hypertensive with left ventricular hypertrophy, and myocardial infarction), together with the potential benefit of this class type of pharmacological therapy in direct current cardioversion and after radiofrequency catheter ablation. PMID:19492029

  1. Trends in co-prescribing of angiotensin converting enzyme inhibitors and angiotensin receptor blockers in Ireland

    Science.gov (United States)

    Wan Md Adnan, Wan A H; Zaharan, Nur L; Bennett, Kathleen; Wall, Catherine A

    2011-01-01

    AIMS (i) To examine the trends in co-prescribing of angiotensin converting enzyme inhibitor (ACEI) and angiotensin-II receptor blocker (ARB) therapy and (ii) to examine the influence of major clinical trials (CALM, COOPERATE, VALIANT and ONTARGET) on co-prescribing. METHODS The Irish HSE-Primary Care Reimbursement Services database was used to identify patients ≥16 years old co-prescribed ACEIs and ARBs between January 2000 and April 2009 (n= 266 554 prescriptions). The rate of prescribing per 1000 general medical services (GMS) scheme population was calculated for each month. Patients with diabetes, hypertension, heart failure and ischaemic heart disease were also identified by prescribing of certain medications. A linear trend test was used to examine prescribing trends. Logistic regression was used to examine prescribing according to patient characteristics. The effects of the major trials on prescribing were examined using segmented regression analysis for 12 months pre- and post-trials. RESULTS There was a significant linear trend in overall ACEI and ARB co-prescribing over the study period (P ACEIs and ARBs was observed in Ireland during 2000–09. Prescribing patterns did not appear to be affected by results from major trials. PMID:21284706

  2. The Fetal Safety of Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers

    Directory of Open Access Journals (Sweden)

    Myla E. Moretti

    2012-01-01

    Full Text Available Angiotensin converting enzyme (ACE inhibitors and angiotensin II receptor blockers (ARBs are known to cause fetal renal damage in pregnancy. Due to conflicting reports in the literature, their safety after first trimester exposure has been debated. Our aim was to determine whether the use of ACE inhibitors or ARBs in the first trimester of pregnancy is associated with an increased risk for major malformations or other adverse outcomes. All subjects were prospectively enrolled from among women contacting a teratogen information service. At initial contact, details of maternal medical history and exposures were collected and follow-up interviews were conducted to ascertain pregnancy outcomes. Two comparator groups, women with hypertension treated with other antihypertensives, and healthy controls were also recruited. Baseline maternal characteristics were not different among the three groups. There were no differences in rates of major malformations. Both the ACE-ARBs and disease-matched groups exhibited significantly lower birth weight and gestational ages than the healthy controls (P<0.001 for both variables. There was a significantly higher rate of miscarriage noted in the ACE/ARB group (P<0.001. These results suggest that ACE inhibitors/ARBs are not major human teratogens; however, they may be associated with an increased risk for miscarriage.

  3. The expression of Mas-receptor of the renin-angiotensin system in the human eye.

    Science.gov (United States)

    Vaajanen, A; Kalesnykas, G; Vapaatalo, H; Uusitalo, H

    2015-07-01

    The local renin-angiotensin system has been held to be expressed in many organs, including the eye. It has an important role in the regulation of local fluid homeostasis, cell proliferation, fibrosis, and vascular tone. Mas-receptor (Mas-R) is a potential receptor acting mainly opposite to the well-known angiotensin II receptor type 1. The aim of this study was to determine if Mas-R is expressed in the human eye. Seven enucleated human eyes were used in immunohistochemical detection of Mas-R and its endogenous ligand angiotensin (1-7) [Ang(1-7)]. Both light microscopy and immunofluorescent detection methods were used. A human kidney preparation sample was used as control. The Mas-R was found to have nuclear localization, and localized in the retinal nuclear layers and in the structures of the anterior segment of the eye. A cytoplasmic immunostaining pattern of Ang(1-7) was found in the inner and outer nuclear and plexiform layers of the retina and in the ciliary body. To the best of our knowledge, this is the first report showing Mas-R expression in the human eye. Its localization suggests that it may have a role in physiological and pathological processes in the anterior part of the eye and in the retina.

  4. G protein coupled receptors of the renin-angiotensin system: new targets against breast cancer?

    Directory of Open Access Journals (Sweden)

    Clara eNAHMIAS

    2015-02-01

    Full Text Available G-protein coupled receptors (GPCRs constitute the largest family of membrane receptors, with high potential for drug discovery. These receptors can be activated by a panel of different ligands including ions, hormones, small molecules and vasoactive peptides. Among those, angiotensins (angiotensin II and angiotensin 1-7 are the major biologically active products of the classical and alternative Renin-Angiotensin System (RAS. These peptides bind and activate three different subtypes of GPCRs, namely AT1, AT2 and Mas receptors, to regulate cardiovascular functions. Over the past decade, the contribution of several RAS components in tumorigenesis has emerged as a novel important concept, Angiotensin II being considered as harmful and Angiotensin 1-7 as protective against cancer. Development of selective ligands targeting each RAS receptor may provide novel and efficient targeted therapeutic strategies against cancer. In this review, we focus on breast cancer to summarize current knowledge on angiotensin receptors (AT1, AT2, and Mas, and discuss the potential use of angiotensin receptor agonists and antagonists in clinics.

  5. Sex differences in NMDA GluN1 plasticity in rostral ventrolateral medulla neurons containing corticotropin-releasing factor type 1 receptor following slow-pressor angiotensin II hypertension.

    Science.gov (United States)

    Van Kempen, T A; Dodos, M; Woods, C; Marques-Lopes, J; Justice, N J; Iadecola, C; Pickel, V M; Glass, M J; Milner, T A

    2015-10-29

    There are profound, yet incompletely understood, sex differences in the neurogenic regulation of blood pressure. Both corticotropin signaling and glutamate receptor plasticity, which differ between males and females, are known to play important roles in the neural regulation of blood pressure. However, the relationship between hypertension and glutamate plasticity in corticotropin-releasing factor (CRF)-receptive neurons in brain cardiovascular regulatory areas, including the rostral ventrolateral medulla (RVLM) and paraventricular nucleus of the hypothalamus (PVN), is not understood. In the present study, we used dual-label immuno-electron microscopy to analyze sex differences in slow-pressor angiotensin II (AngII) hypertension with respect to the subcellular distribution of the obligatory NMDA glutamate receptor subunit 1 (GluN1) subunit of the N-methyl-D-aspartate receptor (NMDAR) in the RVLM and PVN. Studies were conducted in mice expressing the enhanced green fluorescence protein (EGFP) under the control of the CRF type 1 receptor (CRF1) promoter (i.e., CRF1-EGFP reporter mice). By light microscopy, GluN1-immunoreactivity (ir) was found in CRF1-EGFP neurons of the RVLM and PVN. Moreover, in both regions tyrosine hydroxylase (TH) was found in CRF1-EGFP neurons. In response to AngII, male mice showed an elevation in blood pressure that was associated with an increase in the proportion of GluN1 on presumably functional areas of the plasma membrane (PM) in CRF1-EGFP dendritic profiles in the RVLM. In female mice, AngII was neither associated with an increase in blood pressure nor an increase in PM GluN1 in the RVLM. Unlike the RVLM, AngII-mediated hypertension had no effect on GluN1 localization in CRF1-EGFP dendrites in the PVN of either male or female mice. These studies provide an anatomical mechanism for sex-differences in the convergent modulation of RVLM catecholaminergic neurons by CRF and glutamate. Moreover, these results suggest that sexual dimorphism in

  6. Exogenous angiotensin II does not facilitate norepinephrine release in the heart

    NARCIS (Netherlands)

    Th.W. Lameris (Thomas); P.A. de Zeeuw (Sandra); D.J.G.M. Duncker (Dirk); G. Alberts; F. Boomsma (Frans); P.D. Verdouw (Pieter); A.H. van den Meiracker (Anton)

    2002-01-01

    textabstractStudies on the effect of angiotensin II on norepinephrine release from sympathetic nerve terminals through stimulation of presynaptic angiotensin II type 1 receptors are equivocal. Furthermore, evidence that angiotensin II activates the cardiac sympathetic nervous syste

  7. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers reduced dementia risk in patients with diabetes mellitus and hypertension.

    Science.gov (United States)

    Kuan, Yi-Chun; Huang, Kuang-Wei; Yen, Der-Jen; Hu, Chaur-Jong; Lin, Cheng-Li; Kao, Chia-Hung

    2016-10-01

    The effects of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) on dementia risk in patients with type 2 diabetes mellitus (DM) and hypertension remain unknown. We investigated the effects of ACEIs and ARBs on dementia risk in patients with type 2 DM and hypertension. We conducted a cohort study by using the Taiwan National Health Insurance Research Database. We included 2377 patients receiving ACEIs and 1780 patients receiving ARBs in the ACEI and ARB cohorts, respectively. We included a comparable number of patients not receiving ACEIs and ARBs as controls in the non-ACEI and non-ARB cohorts through propensity score matching. The effect of ACEIs and ARBs on dementia risk was estimated through multivariate Cox proportional hazard regression after adjustment for several confounding factors. During the 12-year follow-up period, compared with the non-ACEI cohort, all-cause dementia risk decreased by 26% in the ACEI cohort [hazard ratio (HR)=0.74, 95% confidence interval (CI)=0.56-0.96]. The all-cause dementia risk was nearly 40% lower in the ARB cohort than in the non-ARB cohort (HR=0.60, 95% CI=0.37-0.97). These drugs prevented the occurrence of vascular dementia (VD), however, this effect was nonsignificant for Alzheimer's dementia (AD). Treatment duration- and dosage-related protection effects on dementia occurrence were observed. ACEIs and ARBs may effectively prevent all-cause dementia, particularly VD, in patients with type 2 DM and hypertension. Moreover, compared with ACEIs, ARBs appear to be more advantageous in dementia prevention. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Complete blockade of the vasorelaxant effects of angiotensin-(1-7) and bradykinin in murine microvessels by antagonists of the receptor Mas.

    Science.gov (United States)

    Peiró, Concepción; Vallejo, Susana; Gembardt, Florian; Palacios, Erika; Novella, Susana; Azcutia, Verónica; Rodríguez-Mañas, Leocadio; Hermenegildo, Carlos; Sánchez-Ferrer, Carlos F; Walther, Thomas

    2013-05-01

    The heptapeptide angiotensin-(1-7) is a biologically active metabolite of angiotensin II, the predominant peptide of the renin-angiotensin system. Recently, we have shown that the receptor Mas is associated with angiotensin-(1-7)-induced signalling and mediates, at least in part, the vasodilatory properties of angiotensin-(1-7). However, it remained controversial whether an additional receptor could account for angiotensin-(1-7)-induced vasorelaxation. Here, we used two different angiotensin-(1-7) antagonists, A779 and d-Pro-angiotensin-(1-7), to address this question and also to study their influence on the vasodilatation induced by bradykinin. Isolated mesenteric microvessels from both wild-type and Mas-deficient C57Bl/6 mice were precontracted with noradrenaline, and vascular reactivity to angiotensin-(1-7) and bradykinin was subsequently studied using a small-vessel myograph. Furthermore, mechanisms for Mas effects were investigated in primary human umbilical vein endothelial cells. Both angiotensin-(1-7) and bradykinin triggered a concentration-dependent vasodilatation in wild-type microvessels, which was absent in the presence of a nitric oxide synthase inhibitor. In these vessels, the pre-incubation with the Mas antagonists A779 or d-Pro-angiotensin-(1-7) totally abolished the vasodilatory capacity of both angiotensin-(1-7) and bradykinin, which was nitric oxide mediated. Accordingly, Mas-deficient microvessels lacked the capacity to relax in response to either angiotensin-(1-7) or bradykinin. Pre-incubation of human umbilical vein endothelial cells with A779 prevented bradykinin-mediated NO generation and NO synthase phosphorylation at serine 1177. The angiotensin-(1-7) antagonists A779 and d-Pro-angiotensin-(1-7) equally block Mas, which completely controls the angiotensin-(1-7)-induced vasodilatation in mesenteric microvessels. Importantly, Mas also appears to be a critical player in NO-mediated vasodilatation induced by renin-angiotensin system

  9. Activation of intracellular angiotensin AT₂ receptors induces rapid cell death in human uterine leiomyosarcoma cells.

    Science.gov (United States)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen; Zuhayra, Maaz; Schütze, Stefan; Steckelings, Ulrike M; Recanti, Chiara; Namsoleck, Pawel; Unger, Thomas; Culman, Juraj

    2015-05-01

    The presence of angiotensin type 2 (AT₂) receptors in mitochondria and their role in NO generation and cell aging were recently demonstrated in various human and mouse non-tumour cells. We investigated the intracellular distribution of AT₂ receptors including their presence in mitochondria and their role in the induction of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT₂ receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high densities in mitochondria. Activation of the cell membrane AT₂ receptors by a concomitant treatment with angiotensin II and the AT₁ receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT₂ receptor agonist, Compound 21 (C21), penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT₂ receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped cell death, displayed activation of the mitochondrial apoptotic pathway, i.e. down-regulation of the Bcl-2 protein, induction of the Bax protein and activation of caspase-3. All quiescent SK-UT-1 cells died within 5 days after treatment with a single dose of C21. C21 was devoid of cytotoxic effects in proliferating SK-UT-1 cells and in quiescent HutSMC. Our results point to a new, unique approach enabling the elimination non-cycling uterine leiomyosarcoma cells providing that they over-express the AT₂ receptor.

  10. Is there a place for combining angiotensin-converting enzyme inhibitors and angiotensin-receptor antagonists in the treatment of hypertension, renal disease or congestive heart failure?

    Science.gov (United States)

    Taylor, A A

    2001-09-01

    Angiotensin-converting enzyme inhibitors and angiotensin II receptor subtype 1 antagonists have proven to be effective and well tolerated antihypertensive agents. They also exhibit unique cardioprotective and renoprotective properties in patients with comorbid conditions such as congestive heart failure and proteinuria or renal insufficiency. This benefit is observed most dramatically in diabetic persons. Although inconclusive, the results of a limited number of clinical trials support the notion that additive antihypertensive, cardioprotective, and renoprotective effects may be obtained with combined used of angiotensin-converting enzyme inhibitors and angiotensin II receptor subtype 1 antagonists in some patients. More studies are needed to confirm the findings of these preliminary studies, and to define more clearly those subsets of patients who might derive the greatest benefit from angiotensin-converting enzyme inhibitor-angiotensin II receptor subtype 1 antagonist combination therapy.

  11. Renin angiotensin system blockade reduces urinary levels of soluble urokinase plasminogen activator receptor (suPAR) in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Persson, Frederik; Theilade, Simone; Eugen-Olsen, Jesper;

    2016-01-01

    Soluble urokinase plasminogen activator receptor (suPAR) is associated with faster decline in kidney function and the pathogenesis of diabetic nephropathy. However, little is known about the impact of treatment on plasma and urinary levels of suPAR. We aimed to investigate the impact of renin ang...

  12. Update on the Angiotensin converting enzyme 2-Angiotensin (1-7)-MAS receptor axis: fetal programing, sex differences, and intracellular pathways.

    Science.gov (United States)

    Chappell, Mark C; Marshall, Allyson C; Alzayadneh, Ebaa M; Shaltout, Hossam A; Diz, Debra I

    2014-01-09

    The renin-angiotensin-system (RAS) constitutes an important hormonal system in the physiological regulation of blood pressure. Indeed, dysregulation of the RAS may lead to the development of cardiovascular pathologies including kidney injury. Moreover, the blockade of this system by the inhibition of angiotensin converting enzyme (ACE) or antagonism of the angiotensin type 1 receptor (AT1R) constitutes an effective therapeutic regimen. It is now apparent with the identification of multiple components of the RAS that the system is comprised of different angiotensin peptides with diverse biological actions mediated by distinct receptor subtypes. The classic RAS can be defined as the ACE-Ang II-AT1R axis that promotes vasoconstriction, sodium retention, and other mechanisms to maintain blood pressure, as well as increased oxidative stress, fibrosis, cellular growth, and inflammation in pathological conditions. In contrast, the non-classical RAS composed of the ACE2-Ang-(1-7)-Mas receptor axis generally opposes the actions of a stimulated Ang II-AT1R axis through an increase in nitric oxide and prostaglandins and mediates vasodilation, natriuresis, diuresis, and oxidative stress. Thus, a reduced tone of the Ang-(1-7) system may contribute to these pathologies as well. Moreover, the non-classical RAS components may contribute to the effects of therapeutic blockade of the classical system to reduce blood pressure and attenuate various indices of renal injury. The review considers recent studies on the ACE2-Ang-(1-7)-Mas receptor axis regarding the precursor for Ang-(1-7), the intracellular expression and sex differences of this system, as well as an emerging role of the Ang1-(1-7) pathway in fetal programing events and cardiovascular dysfunction.

  13. Update on the Angiotensin Converting Enzyme 2-Angiotensin (1–7)-Mas Receptor Axis: Fetal Programing, Sex Differences, and Intracellular Pathways

    Science.gov (United States)

    Chappell, Mark C.; Marshall, Allyson C.; Alzayadneh, Ebaa M.; Shaltout, Hossam A.; Diz, Debra I.

    2013-01-01

    The renin-angiotensin-system (RAS) constitutes an important hormonal system in the physiological regulation of blood pressure. Indeed, dysregulation of the RAS may lead to the development of cardiovascular pathologies including kidney injury. Moreover, the blockade of this system by the inhibition of angiotensin converting enzyme (ACE) or antagonism of the angiotensin type 1 receptor (AT1R) constitutes an effective therapeutic regimen. It is now apparent with the identification of multiple components of the RAS that the system is comprised of different angiotensin peptides with diverse biological actions mediated by distinct receptor subtypes. The classic RAS can be defined as the ACE-Ang II-AT1R axis that promotes vasoconstriction, sodium retention, and other mechanisms to maintain blood pressure, as well as increased oxidative stress, fibrosis, cellular growth, and inflammation in pathological conditions. In contrast, the non-classical RAS composed of the ACE2-Ang-(1–7)-Mas receptor axis generally opposes the actions of a stimulated Ang II-AT1R axis through an increase in nitric oxide and prostaglandins and mediates vasodilation, natriuresis, diuresis, and oxidative stress. Thus, a reduced tone of the Ang-(1–7) system may contribute to these pathologies as well. Moreover, the non-classical RAS components may contribute to the effects of therapeutic blockade of the classical system to reduce blood pressure and attenuate various indices of renal injury. The review considers recent studies on the ACE2-Ang-(1–7)-Mas receptor axis regarding the precursor for Ang-(1–7), the intracellular expression and sex differences of this system, as well as an emerging role of the Ang1-(1–7) pathway in fetal programing events and cardiovascular dysfunction. PMID:24409169

  14. Hypotensive effect of angiotensin II after AT1-receptor blockade with losartan.

    Science.gov (United States)

    Matys, T; Pawlak, R; Kucharewicz, I; Chabielska, E; Buczko, W

    2000-03-01

    Recent data suggest that hypotensive effect of losartan may not be attributed solely to AT1-receptor blockade, but also to excessive AT2 or other receptors stimulation by elevated angiotensin II and its derivative peptides. Therefore in the present study we examined the effect of angiotensin II on mean blood pressure after AT -receptor blockade with losartan. Male Wistar rats were anaesthetised and received injection of either losartan (30 mg/kg, 1 ml/kg, i.v.) or saline (the same volume and route) followed by bolus injection of angiotensin II (100, 300 or 1,000 ng/kg; 1 ml/kg, i.v.) or 1-hour infusion of angiotensin II (200 ng/kg/min; 2.5 ml/kg/h, i.v.). Control animals received saline instead. Angiotensin II, given either as the injection or the infusion, caused an evident increase in mean blood pressure (p ranged from 0.05 to 0.001 depending on the experimental group). Losartan caused a rapid drop in mean blood pressure and blunted the hypertensive effect of angiotensin II (p < 0.01). Moreover, in the losartan-pretreated animals the hypotensive phase was enhanced by the infusion, but not single injection of angiotensin II, which was most evident from the 30 th minute of observation (p < 0.05 vs control). In conclusion, hypotensive effect of losartan may be amplified by simultaneous increase in angiotensin II level, the situation observed during chronic AT1-receptor blockade.

  15. Prediction of severe hypoglycaemia by angiotensin-converting enzyme activity and genotype in type 1 diabetes

    DEFF Research Database (Denmark)

    Pedersen-Bjergaard, U; Agerholm-Larsen, Birgit; Pramming, S

    2003-01-01

    AIMS/HYPOTHESIS: We have previously shown a strong relationship between high angiotensin-converting enzyme (ACE) activity, presence of the deletion (D) allele of the ACEgene and recall of severe hypoglycaemic events in patients with Type 1 diabetes. This study was carried out to assess...... this relationship prospectively. METHODS: We followed 171 adult outpatients with Type 1 diabetes in a one-year observational study with the recording of severe hypoglycaemia. Participants were characterised by serum ACE activity and ACE genotype and not treated with ACE inhibitors or angiotensin II receptor...... antagonists. RESULTS: There was a positive relationship between serum ACE activity and rate of severe hypoglycaemia with a 2.7 times higher rate in the fourth quartile of ACE activity compared to the first quartile (p=0.0007). A similar relationship was observed for the subset of episodes with coma (2.9 times...

  16. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in high vascular risk.

    Science.gov (United States)

    Potier, Louis; Roussel, Ronan; Elbez, Yedid; Marre, Michel; Zeymer, Uwe; Reid, Christopher M; Ohman, Magnus; Eagle, Kim A; Bhatt, Deepak L; Steg, Philippe Gabriel

    2017-09-01

    ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are widely prescribed in patients with high cardiovascular (CV) risk. However, whether both classes have equivalent effectiveness to prevent CV events remains unclear. The aim of this study was to compare the incidence of major CV events between ACEI and ARB users. The Reduction of Atherothrombosis for Continued Health registry is an observational study who enrolled 69 055 individuals with high CV risk. Among them, 40 625 patients (ACEIs 67.9% and ARBs 32.1%) were included. Main outcome was rates of CV mortality, non-fatal myocardial infarction, non-fatal stroke or hospitalisation for CV disease at 4 years. In a propensity score-adjusted cohort, the incidence of the primary outcome was lower in patients on ARBs compared with ACEIs (29.2% vs 33.4%; adjusted HR 0.90; 95% CI 0.86 to 0.95; pACEIs, especially in patients with established CV disease. Our results suggest that ARBs may provide superior protection against CV events than ACEIs in high-risk patients in real-world practice. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. Vascular hypothesis revisited: Role of stimulating antibodies against angiotensin and endothelin receptors in the pathogenesis of systemic sclerosis.

    Science.gov (United States)

    Cabral-Marques, Otavio; Riemekasten, Gabriela

    2016-07-01

    Systemic sclerosis (SSc) is a connective tissue disorder of unknown etiology characterized by the presence of multiple autoantibodies, including those against angiotensin and endothelin receptors. Patients with SSc can develop heterogeneous clinical manifestations including microvascular damage, the dysregulation of innate and adaptive immunity, and generalized fibrosis of multiple organs. Autoantibodies against angiotensin II type I receptor (AT1R) and endothelin-1 type A receptor (ETAR) play important roles in the pathogenesis of SSc. These autoantibodies regulate physiological processes ranging from production of collagen by skin fibroblasts to angiogenesis modulation. Understanding the mechanisms behind autoantibodies against AT1R and ETAR could provide insight to future novel therapies for SSc patients. In this review, we focus on elucidating the immunopathological mechanisms triggered by anti-AT1R and anti-ETAR autoantibodies to summarize current knowledge about vascular abnormalities resulting in progressive damage of organs seen in patients with SSc.

  18. Modulation of Calcium Signaling of Angiotensin AT1, Endothelin ETA, and ETB Receptors by Silibinin, Quercetin, Crocin, Diallyl Sulfides, and Ginsenoside Rb1.

    Science.gov (United States)

    Bahem, Ruba; Hoffmann, Anja; Azonpi, Arnaud; Caballero-George, Catherina; Vanderheyden, Patrick

    2015-06-01

    Angiotensin II and endothelin-1 are potent vasoconstrictive peptides that play a central role in blood pressure regulation. Both peptides exert their pleiotropic effects via binding to their respective G-protein-coupled receptors, i.e., angiotensin AT1 and endothelin type A and type B receptors. In the present study, we have selected six structurally different plant-derived compounds with known cardioprotective properties to evaluate their ability to modulate calcium signaling of the above-mentioned receptors. For this purpose, we used and validated a cellular luminescence-based read-out system in which we measured intracellular calcium signaling in Chinese hamster ovary cells that express the calcium sensitive apo-aequorin protein. Firstly, silibinin, a flavanolignan that occurs in milk thistle (Silybum marianum), was investigated and found to be an antagonist for the human angiotensin AT1 receptor with an affinity constant of about 9 µM, while it had no effect on endothelin type A or type B receptor activation. Quercetin and crocin partially impeded intracellular calcium signaling resulting in a non-receptor-related reduction of the responses recorded for the three investigated G-protein-coupled receptors. Two organosulfur compounds, diallyl disulfide and diallyl trisulfide, as well as the triterpene saponin ginsenoside Rb1 did not affect the activation of the angiotensin AT1 and endothelin type A and type B receptors. In conclusion, we were able, by using a nonradioactive cellular read-out system, to identify a novel pharmacological property of the flavanolignan silibinin.

  19. Update on the Angiotensin Converting Enzyme 2-Angiotensin (1-7-Mas Receptor Axis: Fetal Programming, Sex Differences and Intracellular Pathways

    Directory of Open Access Journals (Sweden)

    Mark C. Chappell

    2014-01-01

    Full Text Available The renin-angiotensin-system (RAS constitutes an important hormonal system in the physiological regulation of blood pressure. Indeed, dysregulation of the RAS may lead to the development of cardiovascular pathologies including kidney injury. Moreover, the blockade of this system by the inhibition of angiotensin converting enzyme (ACE or antagonism of the angiotensin type 1 receptor (AT1R constitutes an effective therapeutic regimen. It is now apparent with the identification of multiple components of the RAS that the system is comprised of different angiotensin peptides with diverse biological actions mediated by distinct receptor subtypes. The classic RAS can be defined as the ACE-Ang II-AT1R axis that promotes vasoconstriction, sodium retention and other mechanisms to maintain blood pressure, as well as increased oxidative stress, fibrosis, cellular growth and inflammation in pathological conditions. In contrast, the non-classical RAS composed of the ACE2-Ang-(1-7-AT7R axis generally opposes the actions of a stimulated Ang II-AT1R axis through an increase in nitric oxide and prostaglandins and mediates vasodilation, natriuresis, diuresis and oxidative stress. Thus, a reduced tone of the Ang-(1-7 system may contribute to these pathologies as well. Moreover, the non-classical RAS components may contribute to the effects of therapeutic blockade of the classical system to reduce blood pressure and attenuate various indices of renal injury. The review considers recent studies on the ACE2-Ang-(1-7-Mas receptor axis regarding the precursor for Ang-(1-7, the intracellular expression and sex differences of this system, as well as an emerging role of the Ang1-(1-7 pathway in fetal programming events and cardiovascular dysfunction.

  20. The effects of blocking angiotensin receptors on early stages of diabetic nephropathy

    Directory of Open Access Journals (Sweden)

    Alaleh Gheissari

    2012-01-01

    Conclusion: Angiotensin receptor blockers may reduce VCAM-1 and microalbuminuria and may increase NO levels in early stages of DN. Thus administration of ARBs might be considered even in early stages of DN.

  1. Serum metabolites predict response to angiotensin II receptor blockers in patients with diabetes mellitus

    NARCIS (Netherlands)

    Pena, Michelle J.; Heinzel, Andreas; Rossing, Peter; Parving, Hans-Henrik; Dallmann, Guido; Rossing, Kasper; Andersen, Steen; Mayer, Bernd; Heerspink, Hiddo J. L.

    2016-01-01

    Background: Individual patients show a large variability in albuminuria response to angiotensin receptor blockers (ARB). Identifying novel biomarkers that predict ARB response may help tailor therapy. We aimed to discover and validate a serum metabolite classifier that predicts albuminuria response

  2. Efficacy and safety of the angiotensin II receptor blocker losartan for hypertrophic cardiomyopathy

    DEFF Research Database (Denmark)

    Axelsson, Anna; Iversen, Kasper; Vejlstrup, Niels;

    2015-01-01

    BACKGROUND: No medical treatment has been reliably shown to halt or reverse disease progression in hypertrophic cardiomyopathy, but the results of several pilot studies have suggested beneficial effects of angiotensin II receptor blockers on left ventricular hypertrophy and fibrosis, which...

  3. Prospects for angiotensin receptor blockers in diabetic retinopathy

    DEFF Research Database (Denmark)

    Sjølie, Anne Katrin

    2007-01-01

    Retinopathy is the most common microvascular complication of diabetes mellitus, and is an important cause of blindness worldwide. Clinical trials have demonstrated that tight metabolic control inhibits the progression of retinopathy. Good blood pressure control has been shown to be protective...... in type 2 diabetes, and it may also reduce proliferative retinopathy in type 1 diabetes. However, such control is often difficult to achieve in clinical practice, and may be associated with problems such as hypoglycaemia. New therapies are therefore needed to reduce the risk of retinopathy....... There is growing evidence that the renin-angiotensin system (RAS) plays an important role in the pathogenesis of diabetic retinopathy, and this has led to interest in RAS inhibitors as agents to prevent retinopathy. Several trials have suggested that ACE inhibitor therapy can inhibit progression of retinopathy...

  4. The Divergent Cardiovascular Effects of Angiotensin Converting Enzyme Inhibitors and Angiotensin Receptor Blockers on Myocardial Infarction and Death.

    Science.gov (United States)

    Strauss, Martin H; Hall, Alistair S

    2016-01-01

    The renin angiotensin aldosterone system (RAAS) plays a central role in the pathophysiology of hypertension and vascular disease. Angiotensin converting enzyme inhibitors (ACEis) suppress angiotensin II (ANG II) concentrations, whereas angiotensin receptor blockers (ARBs) block the binding of ANG II to AT1 receptors. ACEis and ARBs are both effective anti-hypertensive agents and have similar risk reductions in stroke - a blood pressure dependent phenomenon. ACEis also reduce the risk of myocardial infarction (MI) and mortality in high risk hypertensive patients, as well as in diabetics, the elderly, those with vascular disease, and in congestive heart failure. ARBs, in contrast, do not reduce the risk of MI or death in clinical trials where the comparator has been another active therapy or even a placebo. Systematic reviews of ARBs that include meta-analyses or meta-regression analyses confirm that ARBs lack the cardiovascular protective effects of ACEis, which in part are "independent" of blood pressure lowering. Practice guidelines, especially those in high risk hypertensive patients, should reflect the evidence that ACEis and ARBs have divergent cardiovascular effects - ACEis reduce mortality, whereas ARBs do not. ACEis should be the preferred RAAS inhibitor in high risk patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Des-aspartate-angiotensin I causes specific release of PGE2 and PGI2 in HUVEC via the angiotensin AT1 receptor and biased agonism.

    Science.gov (United States)

    Wen, Qiang; Lee, Kok-Onn; Sim, Sai-Zhen; Xu, Xiao-Guang; Sim, Meng-Kwoon

    2015-12-05

    DAA-I (des-aspartate-angiotensin I), an endogenous angiotensin, had been shown earlier to ameliorate animal models of cardiovascular diseases via the angiotensin AT1 receptor and prostaglandins. The present study investigated further the action of DAA-I on the release of PGE2, PGI2, PGF2α and TXA2 in HUVEC. 10(-11)-10(-8)M DAA-I and 15min incubation specifically released PGE2 and PGI2. The release was inhibited by losartan and indomethacin but not by PD123319 and NS398 indicating that the angiotensin AT1 receptor and COX-1 mediate the release. At concentrations higher than 10(-7)M, DAA-I mimics the action of angiotensin II by releasing TXA2 but had no effect on the production of PGF2α. At similar concentrations and 4h incubation, DAA-I increased the release of the 4 prostaglandins via the angiotensin AT1 receptor and COX-2, again mimicking the action of angiotensin II. HUVEC that were preincubated with DAA-I or angiotensin II, released similar profiles of prostaglandins when incubated with arachidonic acid after the angiotensin had been washed off. We postulate that the internalized DAA-I/receptor complex remains active and mediates the conversion of arachidonic acid to the respective prostaglandins. The release of PGE2 and PGI2 via the angiotensin AT1 receptor and COX-1 is a novel specific action of DAA-I and is likely responsible for its beneficial effects seen in earlier studies. This specific action is definable as a biased agonism of the angiotensin AT1 receptor, which identifies DAA-I as a novel biased agonist and potential therapeutic that is able to produce specific prostaglandins at nanomolar concentrations.

  6. Quantitative autoradiography of angiotensin II receptors in the brain and kidney

    Energy Technology Data Exchange (ETDEWEB)

    Gehlert, D.R.

    1985-01-01

    The renin-angiotensin system is an important component in the regulation of systemic blood pressure. Angiotensin II is the principal effector peptide of this system. Interaction of angiotensin II with specific receptors can produce in several organic systems. When administered into the brain this octa-peptide produces a variety of responses including a stimulation of drinking, increased systemic blood pressure and several neuroendocrine responses. Its effects on the kidney include alterations in arteriolar resistance, mesangial cell contraction and a feedback inhibition of the release of renin. Since this peptide produces profound effects on homeostatis by an interaction with specific receptors, the quantitative technique of in vitro autoradiography was applied to localize receptor populations for angiotensin II. Specific binding sites for a radiolabeled form of angiotensin II were localized in various brain and kidney regions. In the rat brain high densities of angiotensin II receptors were observed in the paraventricular and suprachiasmatic nuclei of the hypothalamus, supraoptic nucleus and the posterior lobe of the pituitary, brain areas in which angiotensin II modified neuroendocrine functions.

  7. [Immunomodulating, metabolic and cardioprotective effects of AT1-angiotensin receptors blocker losartan in patients with coronary heart disease and type 2 diabetes mellitus].

    Science.gov (United States)

    Tepliakov, A T; Maianskaia, S D; Bolotskaia, L A; Vdovina, T V; Stepacheva, T A; Kuznetsova, A V; Lukinov, A V; Derbeneva, N V; Frants, M V; Shilov, S N

    2009-01-01

    To evaluate effects of 6-month therapy with losartan in combination with indapamide on a clinical course, immunological, metabolic parameters, left ventricular function, exercise tolerance and quality of life in patients with coronary heart disease (CHD) associated with metabolic syndrome (MS). Forty six CHD patients with postinfarction cardiac dysfunction in MS were randomized into two groups. Group 1 consisted of 22 patients with impaired glucose tolerance, group 2--of 24 type 2 diabetics. Treatment included combination of losartan (50 mg/day) with indapamide (1.5 mg/day), on demand nitrates, nebivolol. Basic therapy in diabetes included sugar-reducing drugs. Clinical condition, findings of echocardiography, parameters of lipid and carbohydrate metabolisms, immunoglobulins, circulating immune complexes, autoantibodies to cardiolipin (AB to CL), spectrum of proinflammatory cytokines were studied before and 3 months after course treatment. Overactivation of cytokines (primarily IL-2, IL-1, TNF alpha) with high expression of IgA, IgG, CIC, AB to CL was found in CHD patients with type 2 diabetes mellitus and less evident in impaired glucose tolerance. Losartan in both groups had an antihypertensive effect, stabilized LV hypertrophy, improved clinical symptoms leading to cytokines expression decline: TNF alpha by 9.8%, IL-1--by 6.1%, IL-6--by 6.7%. Losartan was well tolerated, caused no negative metabolic effects. New original facts of cytokine overactivation and humoral immunity disturbances were discovered which play an essential role in pathogenesis of postinfarction dysfunction and LV remodeling developing in type 2 diabetes mellitus. Losartan 6-month treatment in the fixed combination has a positive effect on clinicohemodynamic and immunometabolic indices. This gives grounds for wider use of losartan in CHD combined with type 2 diabetes mellitus.

  8. Activation of ERK, JNK, Akt, and G-protein coupled signaling by hybrid angiotensin II AT1/bradykinin B2 receptors expressed in HEK-293 cells

    DEFF Research Database (Denmark)

    Yu, Jun; Lubinsky, David; Tsomaia, Natia;

    2007-01-01

    Bradykinin (BK) and angiotensin II (AngII) often have opposite roles in cardiovascular diseases. Our aim here was to construct hybrid receptors which bind AngII but signal as BK. Various sequences of the intracellular face of the AngII type I receptor, AT1R, were replaced with corresponding...

  9. Genetic variation and activity of the renin-angiotensin system and severe hypoglycemia in type 1 diabetes

    DEFF Research Database (Denmark)

    Pedersen-Bjergaard, Ulrik; Dhamrait, Sukhbir S.; Sethi, Amar A

    2008-01-01

    BACKGROUND: The deletion-allele of the angiotensin-converting enzyme (ACE) gene and elevated ACE activity are associated with increased risk of severe hypoglycemia in type 1 diabetes. We explored whether genetic and phenotypic variations in other components of the renin-angiotensin system...... are similarly associated. METHODS: Episodes of severe hypoglycemia were recorded in 171 consecutive type 1 diabetic outpatients during a 1-year follow-up. Participants were characterized at baseline by gene polymorphisms in angiotensinogen, ACE, angiotensin-II receptor types 1 (AT1R) and 2 (AT2R), and by plasma...... angiotensinogen concentration and serum ACE activity. RESULTS: Three risk factors for severe hypoglycemia were identified: plasma angiotensinogen concentration in the upper quartile (relative rate [RR] vs. lower quartile 3.1, 95% confidence interval [CI,] 1.4-6.8), serum ACE activity in the upper quartile (RR vs...

  10. EFFECT OF ANGIOTENSIN II RECEPTOR ANTAGONIST AND ENDOTHELIN RECEPTOR ANTAGONIST ON NITROGLYCERIN TOLERANCE IN RATS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective. To investigate whether angiotensin II receptor antagonist and endothelin receptor antagonist can improve the nitroglycerin (Nit) tolerance in vivo. Methods. Twenty-four rats were divided into 4 groups (n=6,each): Control group, Nitroglycerin (Nit) group, Nit+ bosentan group and Nit+ losartan group. Nitroglycerin tolerance was induced by 2-day treatment of nitroglycerin patch (0.05 mg/h). AngiotensinⅡ receptor antagonist losartan ( 10 mg· kg- 1· d- 1 ) and endothelin receptor antagonist bosentan ( 100 mg· kg- 1· d- 1 ) were given by gavage for 2 days respectively. Results. The least hypotensive response to sodium nitroprusside (SNP) was observed in Nit group . The effective percentages of hypotensive response to SNP were increased in both Nit+ losartan group and Nit+ bosentan group compared with Nit group [(31.95± 4.45 ) % vs (21.00± 3.69 ) % , P Conclusion. Endothelin receptor antagonist and angiotensinreceptor antagonist could prevent against the Nit tolerance .

  11. Association of Polymorphisms of β3-Adrenergic Receptor,Angiotensinogen and Angiotensin-Converting Enzyme Gene with Hypertension in type 2 DM

    Institute of Scientific and Technical Information of China (English)

    丁国宪; 沈捷; 陈家伟

    2002-01-01

    ObjectiveTo explore the relationship between the mutant genes of ACE,ATN,β3-AR and hypertension in patients with type 2 DM.Methods281 recruited Chinese subjects were divided into two groups according to the mellitus (DM):112 cases.The subjects were genotyped for the ACE gene,the ATN gene and the codon 64 of β3-AR gene polymorphisms by applying polymerase chain reaction (PCR),PCR restriction fragment-length polymorphisms screening with the use of endonuclease.ResultsOur study found that the frequency of D/D genotype and D allele of ACE gene,a/a genotype and an allele of ATN gene in HT patients without DM were increased (P all <0.05);that the frequency of codon 64 mutation of β3-AR gene also increased in HT patients with NGT (P <0.05).In the model of multiple factors non-condition-al Logistic regression analyses,HT had relationship with history of hypertension,age and glucose tolerance (OR=10.745 7,1.780 4,2.034 6;P=0.000 4,0.000 0,0.024 6;respectively),with polymorphism of ATN gene,β3AR gene,ACE gene (OR=2.273 6,1.935 3,1.830 9;P=0.054 3,0.028 7,0.043 2;resceptively).ConclusionThese results suggest that variants of ACE gene,β3AR gene,ATN gene were associated with HT in type 2 DM.``

  12. EFFECT OF ANGIOTENSIN II RECEPTOR ANTAGONIST AND ENDOTHELIN RECEPTOR ANTAGONIST ON NITROGLYCERIN TOLERANCE IN RATS

    Institute of Scientific and Technical Information of China (English)

    张建梅; 陈永红; 王晓红; 唐朝枢

    2001-01-01

    Objective. To investigate whether angiotensin II receptor antagonist and endothelin receptor antagonist can improve the nitroglycerin (Nit) tolerance in vivo. Methods. Twenty-four rats were divided into 4 groups (n =6, each): Control group, Nitroglycerin (Nit) group, Nit + bosentan group and Nit + losartan group. Nitroglycerin tolerance was induced by 2-day treatment ofnitroglycerin patch (0. 05mg/h). Angiotensin I1 receptor antagonist losartan (10mg ·kg-1·d-1) and endothe-lin receptor antagonist bosentan ( 100 mg·kg-1· d-1 ) were given by gavage for 2 days respectively. Results. The least hypotensive response to sodium nitroprusside (SNP) was observed in Nit group. The effec-tive percentages of hypotensive response to SNP were increased in both Nit + losartan group and Nit + bosentangroup compared with Nit group [(31.95±4.45) % vs (21.00±3.69) %, P <0.01and (33. 18±6. 16)% vs (21.00±3.69 ) %, P < 0. 01 , respectivelyl. The maximal vessel relaxation induced by SNP was thesame in 4 different groups but the highest EC50 (concentration which produces 50% of the maximal response toSNP) was found in tolerant group[ (34 ±10) nmol/L, P < 0. 01 ]. The ET-1 amounts in plasma and vasculartissue were markedly increased by 54% and 60% in Nit group compared with those in control group( P<0. 01). The ET-1 amounts in plasma and vascular tissue were decreased by 30% and 37% in Nit + losartangroup compared with those in Nit group ( P < 0.01 ). Conclusion. Endothelin receptor antagonist and angiotensinreceptor antagonist could prevent against the Nit tolerance.

  13. Reduced glomerular angiotensin II receptor density in diabetes mellitus in the rat: time course and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Wilkes, B.M.

    1987-04-01

    Glomerular angiotensin II receptors are reduced in number in early diabetes mellitus, which may contribute to hyperfiltration and glomerular injury. The time course and role of the renin-angiotensin-aldosterone system in the pathogenesis of the receptor abnormality were studied in male Sprague-Dawley rats made diabetic with streptozotocin (65 mg, iv). Glomerular angiotensin II receptors were measured by Scatchard analysis; insulin, renin activity, angiotensin II, and aldosterone were measured by RIA. Diabetes mellitus was documented at 24 h by a rise in plasma glucose (vehicle-injected control, 133 +/- 4; diabetic, 482 +/- 22 mg/dl and a fall in plasma insulin (control, 53.1 +/- 5.7; diabetic, 35.6 +/- 4.0 microIU/ml. At 24 h glomerular angiotensin II receptor density was decreased by 26.5% in diabetic rats (control, 75.5 +/- 9.6 X 10(6); diabetic, 55.5 +/- 8.3 X 10(6) receptors/glomerulus. Receptor occupancy could not explain the defect, because there was reduced binding in diabetic glomeruli after pretreatment with 3 M MgCl/sub 2/, a maneuver that caused dissociation of previously bound hormone. There was a progressive return of the receptor density toward normal over the 60 days following induction of diabetes, with diabetic glomeruli measuring 22.7%, 14.8%, and 3.7% fewer receptors than age-matched controls at 11 days, 1 month, and 2 months, respectively.

  14. The impact of genetic polymorphisms of angiotensin-converting enzyme and angiotensin II type I receptor and their correlation on the prognosis of heart failure%ACE与AT1R基因多态性及其相互作用对心衰预后的影响

    Institute of Scientific and Technical Information of China (English)

    郑茵; 方壮伟; Barry Lon-don; Dennis M. McNamara

    2005-01-01

    本文旨在探讨血管紧张素转换酶(angiotensinconverting enzyme,ACE)基因插入/缺失(I/D)多态性与血管紧张素Ⅱ1型受体(angiotensintype 1 receptor.ATlR)基因多态性及其相互作用对未行心脏移植心衰患者预后的影响.

  15. EGF receptor transactivation in angiotensin II and endothelin control of vascular protein synthesis in vivo.

    Science.gov (United States)

    Beaucage, Pierre; Moreau, Pierre

    2004-11-01

    Endothelin represents a necessary intermediate of angiotensin II-induced resistance artery remodeling in hypertension. Recent data suggest that epidermal growth factor receptors are rapidly transactivated by angiotensin II stimulation to mediate its growth-promoting effects. Because endothelin also transactivates epidermal growth factor receptors in vitro, we studied the contribution of epidermal growth factor receptor transactivation in the in vivo trophic actions of the upstream effector angiotensin II and its downstream mediator endothelin in rat mesenteric arteries. Twenty-six-hour infusion of angiotensin II (400 ng/kg per min) or endothelin (5 pmol/kg per min) via osmotic pumps significantly enhanced vascular protein synthesis. With angiotensin II, treatment with the inhibitor of epidermal growth factor receptor transactivation (AG1478, 0.5 mg/kg) produced a significant attenuation (P < 0.05) of protein synthesis. In contrast, AG1478 did not abrogate the elevation of protein synthesis induced by endothelin. In conclusion, angiotensin II-induced epidermal growth factor receptor transactivation seems to be involved in the recruitment of endothelin in the cascade leading to vascular protein synthesis, rather than in the effect of endothelin on small artery remodeling.

  16. Angiotensin AT1-receptor blockers and cerebrovascular protection: do they actually have a cutting edge over angiotensin-converting enzyme inhibitors?

    DEFF Research Database (Denmark)

    Oprisiu-Fournier, Roxana; Faure, Sébastien; Mazouz, Hakim

    2009-01-01

    is presented to support the hypothesis that antihypertensive drugs that increase angiotensin II formation, such as diuretics, AT1-receptor blockers and dihydropyridines, may have greater brain anti-ischemic effects than antihypertensive drugs that decrease angiotensin II formation, such as beta-blockers...

  17. Effects of the angiotensin-receptor blocker telmisartan on cardiovascular events in high-risk patients intolerant to angiotensin-converting enzyme inhibitors: a randomised controlled trial

    DEFF Research Database (Denmark)

    NN, NN; Yusuf, S; Teo, K;

    2008-01-01

    BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors reduce major cardiovascular events, but are not tolerated by about 20% of patients. We therefore assessed whether the angiotensin-receptor blocker telmisartan would be effective in patients intolerant to ACE inhibitors with cardiovascular...

  18. Predicting Kinase Activity in Angiotensin Receptor Phosphoproteomes Based on Sequence-Motifs and Interactions

    DEFF Research Database (Denmark)

    Bøgebo, Rikke; Horn, Heiko; Olsen, Jesper V;

    2014-01-01

    -arrestin dependent signalling. Two complimentary global phosphoproteomics studies have analyzed the complex signalling induced by the AT1aR. Here we integrate the data sets from these studies and perform a joint analysis using a novel method for prediction of differential kinase activity from phosphoproteomics data......Recent progress in the understanding of seven-transmembrane receptor (7TMR) signalling has promoted the development of a new generation of pathway selective ligands. The angiotensin II type I receptor (AT1aR) is one of the most studied 7TMRs with respect to selective activation of the β...... likely activated kinases. This suggested that AT1aR-dependent signalling activates 48 of the 285 kinases detected in HEK293 cells. Of these, Aurora B, CLK3 and PKG1 have not previously been described in the pathway whereas others, such as PKA, PKB and PKC, are well known. In summary, we have developed...

  19. Chronic allergic pulmonary inflammation is aggravated in angiotensin-(1-7) Mas receptor knockout mice.

    Science.gov (United States)

    Magalhães, Giselle S; Rodrigues-Machado, Maria Glória; Motta-Santos, Daisy; Alenina, Natalia; Bader, Michael; Santos, Robson A; Barcelos, Lucíola S; Campagnole-Santos, Maria José

    2016-12-01

    The angiotensin-(1-7) [ANG-(1-7)]/Mas receptor pathway is currently recognized as a counterbalancing mechanism of the renin-angiotensin system in different pathophysiological conditions. We have previously described that treatment with ANG-(1-7) attenuates lung inflammation and remodeling in an experimental model of asthma. In the present study, we investigated whether lack of the Mas receptor could alter the inflammatory response in a model of chronic allergic lung inflammation induced by ovalbumin (OVA). Mas receptor wild-type (MasWT) and knockout (MasKO) mice were subjected to four doses of OVA (20 μg/mice ip) with a 14-day interval. At the 21st day, nebulization with OVA (1%) was started, three times per week until the 46th day. Control groups received saline (0.9% ip) and were nebulized with saline (0.9%). MasWT-OVA developed a modest inflammatory response and minor pulmonary remodeling to OVA challenge. Strikingly, MasKO-OVA presented a significant increase in inflammatory cell infiltrate, increase in extracellular matrix deposition, increase in thickening of the alveolar parenchyma, increase in thickening of the smooth muscle layer of the pulmonary arterioles, increase in proinflammatory cytokine and chemokine levels in the lungs, characteristic of chronic asthma. Additionally, MasKO-OVA presented an increase in ERK1/2 phosphorylation compared with MasWT-OVA. Furthermore, MasKO-OVA showed a worse performance in a test of maximum physical exercise compared with MasWT-OVA. Our study shows that effects triggered by the Mas receptor are important to attenuate the inflammatory and remodeling processes in a model of allergic lung inflammation in mice. Our data indicate that impairment of the ANG-(1-7)/Mas receptor pathway may lead to worsening of the pathophysiological changes of asthma. Copyright © 2016 the American Physiological Society.

  20. Renin-Angiotensin System Gene Variants and Type 2 Diabetes Mellitus: Influence of Angiotensinogen.

    Science.gov (United States)

    Joyce-Tan, Siew Mei; Zain, Shamsul Mohd; Abdul Sattar, Munavvar Zubaid; Abdullah, Nor Azizan

    2016-01-01

    Genome-wide association studies (GWAS) have been successfully used to call for variants associated with diseases including type 2 diabetes mellitus (T2DM). However, some variants are not included in the GWAS to avoid penalty in multiple hypothetic testing. Thus, candidate gene approach is still useful even at GWAS era. This study attempted to assess whether genetic variations in the renin-angiotensin system (RAS) and their gene interactions are associated with T2DM risk. We genotyped 290 T2DM patients and 267 controls using three genes of the RAS, namely, angiotensin converting enzyme (ACE), angiotensinogen (AGT), and angiotensin II type 1 receptor (AGTR1). There were significant differences in allele frequencies between cases and controls for AGT variants (P = 0.05) but not for ACE and AGTR1. Haplotype TCG of the AGT was associated with increased risk of T2DM (OR 1.92, 95% CI 1.15-3.20, permuted P = 0.012); however, no evidence of significant gene-gene interactions was seen. Nonetheless, our analysis revealed that the associations of the AGT variants with T2DM were independently associated. Thus, this study suggests that genetic variants of the RAS can modestly influence the T2DM risk.

  1. Renin-Angiotensin System Gene Variants and Type 2 Diabetes Mellitus: Influence of Angiotensinogen

    Directory of Open Access Journals (Sweden)

    Siew Mei Joyce-Tan

    2016-01-01

    Full Text Available Genome-wide association studies (GWAS have been successfully used to call for variants associated with diseases including type 2 diabetes mellitus (T2DM. However, some variants are not included in the GWAS to avoid penalty in multiple hypothetic testing. Thus, candidate gene approach is still useful even at GWAS era. This study attempted to assess whether genetic variations in the renin-angiotensin system (RAS and their gene interactions are associated with T2DM risk. We genotyped 290 T2DM patients and 267 controls using three genes of the RAS, namely, angiotensin converting enzyme (ACE, angiotensinogen (AGT, and angiotensin II type 1 receptor (AGTR1. There were significant differences in allele frequencies between cases and controls for AGT variants (P=0.05 but not for ACE and AGTR1. Haplotype TCG of the AGT was associated with increased risk of T2DM (OR 1.92, 95% CI 1.15–3.20, permuted P=0.012; however, no evidence of significant gene-gene interactions was seen. Nonetheless, our analysis revealed that the associations of the AGT variants with T2DM were independently associated. Thus, this study suggests that genetic variants of the RAS can modestly influence the T2DM risk.

  2. 老年原发性高血压AT1一R基因多态性的研究%The Polymorphism of AngiotensinType 1 Receptor Gene in Essential Hypertensive Elders

    Institute of Scientific and Technical Information of China (English)

    方宁远; 张怡; 陆惠华; 邬亦贤; 郑迪辉; 郑道声

    2000-01-01

    目的 研究老年原发性高血压(EH)血管紧张素Ⅱ型受体(AT1一R)基因A/C1166多态性的特征。方法 应用聚合酶链反应一限制性片段长度多态性(PCR—RFLP)技术检测87例汉族老年EH患者和55例正常老年人的AT1-R基因A/C1166多态性分布。结果87例老年EH患者的C1166等位基因频率为0.115,55例正常老年人为0.036,经统计学分析两组间有显著差异(P<0.05)。结论老年EH的患者C1166等位基因频率明显升高,可能为EH发病的危险因素。%Objective This study was to detect the A/C1166 polymorphism of angiotensintype 1 receptor (AT1 - R) gene in the essential hypertensive elder. Methods The A/C1166 polymor-phism of AT1 - R gene was assessed by polymerase chain reaction- restriction fragment length polymor-phism (PCR- RFLP) in a case- control study of 87 EH elders and 55 normotensive elders (NT).Results The genotype frequencies of AA, AC, CC were 0. 805, 0. 161, 0. 034 in EH group and0. 927, 0. 073, 0. 000 in NT group. The frequency of A/C1166 allele was higher in EH group (0. 115)than in NT group (0. 036) (P < 0.05). Conclusion The frequency of C1166 allele was significantlyhigher in EH group than in NT group, which indicated that A/C1166 polymorphism of AT1 - R gene maybe associated with EH in the elderly.

  3. Susceptibility and gene interaction study of the angiotensin II type 1 receptor (AGTR1 gene polymorphisms with non-alcoholic fatty liver disease in a multi-ethnic population.

    Directory of Open Access Journals (Sweden)

    Shamsul Mohd Zain

    Full Text Available Angiotensin II type 1 receptor (AGTR1 has been reported to play a fibrogenic role in non-alcoholic fatty liver disease (NAFLD. In this study, five variants of the AGTR1 gene (rs3772622, rs3772627, rs3772630, rs3772633, and rs2276736 were examined for their association with susceptibility to NAFLD. Subjects made up of 144 biopsy-proven NAFLD patients and 198 controls were genotyped using TaqMan assays. The liver biopsy specimens were histologically graded and scored according to the method of Brunt. Single locus analysis in pooled subjects revealed no association between each of the five variants with susceptibility to NAFLD. In the Indian ethnic group, the rs2276736, rs3772630 and rs3772627 appear to be protective against NAFLD (p = 0.010, p = 0.016 and p = 0.026, respectively. Haplotype ACGCA is shown to be protective against NAFLD for the Indian ethnic subgroup (p = 0.03. Gene-gene interaction between the AGTR1 gene and the patatin-like phospholipase domain-containing 3 (PNPLA3 gene, which we previously reported as associated with NAFLD in this sample, showed a strong interaction between AGTR1 (rs3772627, AGTRI (rs3772630 and PNPLA3 (rs738409 polymorphisms on NAFLD susceptibility (p = 0.007. Further analysis of the NAFLD patients revealed that the G allele of the AGTR1 rs3772622 is associated with increased fibrosis score (p = 0.003. This is the first study that replicates an association between AGTR1 polymorphism and NAFLD, with further details in histological features of NAFLD. There is lack of evidence to suggest an association between any of the five variants of the AGTR1 gene and NAFLD in the Malays and Chinese. In the Indians, the rs2276736, rs3772630 and rs3772627 appear to protect against NAFLD. We report novel findings of an association between the G allele of the rs3772622 with occurrence of fibrosis and of the gene-gene interaction between AGTR1gene and the much-studied PNPLA3 gene.

  4. Susceptibility and gene interaction study of the angiotensin II type 1 receptor (AGTR1) gene polymorphisms with non-alcoholic fatty liver disease in a multi-ethnic population.

    Science.gov (United States)

    Zain, Shamsul Mohd; Mohamed, Zahurin; Mahadeva, Sanjiv; Rampal, Sanjay; Basu, Roma Choudhury; Cheah, Phaik-Leng; Salim, Agus; Mohamed, Rosmawati

    2013-01-01

    Angiotensin II type 1 receptor (AGTR1) has been reported to play a fibrogenic role in non-alcoholic fatty liver disease (NAFLD). In this study, five variants of the AGTR1 gene (rs3772622, rs3772627, rs3772630, rs3772633, and rs2276736) were examined for their association with susceptibility to NAFLD. Subjects made up of 144 biopsy-proven NAFLD patients and 198 controls were genotyped using TaqMan assays. The liver biopsy specimens were histologically graded and scored according to the method of Brunt. Single locus analysis in pooled subjects revealed no association between each of the five variants with susceptibility to NAFLD. In the Indian ethnic group, the rs2276736, rs3772630 and rs3772627 appear to be protective against NAFLD (p = 0.010, p = 0.016 and p = 0.026, respectively). Haplotype ACGCA is shown to be protective against NAFLD for the Indian ethnic subgroup (p = 0.03). Gene-gene interaction between the AGTR1 gene and the patatin-like phospholipase domain-containing 3 (PNPLA3) gene, which we previously reported as associated with NAFLD in this sample, showed a strong interaction between AGTR1 (rs3772627), AGTRI (rs3772630) and PNPLA3 (rs738409) polymorphisms on NAFLD susceptibility (p = 0.007). Further analysis of the NAFLD patients revealed that the G allele of the AGTR1 rs3772622 is associated with increased fibrosis score (p = 0.003). This is the first study that replicates an association between AGTR1 polymorphism and NAFLD, with further details in histological features of NAFLD. There is lack of evidence to suggest an association between any of the five variants of the AGTR1 gene and NAFLD in the Malays and Chinese. In the Indians, the rs2276736, rs3772630 and rs3772627 appear to protect against NAFLD. We report novel findings of an association between the G allele of the rs3772622 with occurrence of fibrosis and of the gene-gene interaction between AGTR1gene and the much-studied PNPLA3 gene.

  5. Moderation of dietary sodium potentiates the renal and cardiovascular protective effects of angiotensin receptor blockers.

    Science.gov (United States)

    Lambers Heerspink, Hiddo J; Holtkamp, Frank A; Parving, Hans-Henrik; Navis, Gerjan J; Lewis, Julia B; Ritz, Eberhard; de Graeff, Pieter A; de Zeeuw, Dick

    2012-08-01

    Dietary sodium restriction has been shown to enhance the short-term response of blood pressure and albuminuria to angiotensin receptor blockers (ARBs). Whether this also enhances the long-term renal and cardiovascular protective effects of ARBs is unknown. Here we conducted a post-hoc analysis of the RENAAL and IDNT trials to test this in patients with type 2 diabetic nephropathy randomized to ARB or non-renin-angiotensin-aldosterone system (non-RAASi)-based antihypertensive therapy. Treatment effects on renal and cardiovascular outcomes were compared in subgroups based on dietary sodium intake during treatment, measured as the 24-h urinary sodium/creatinine ratio of 1177 patients with available 24-h urinary sodium measurements. ARB compared to non-RAASi-based therapy produced the greatest long-term effects on renal and cardiovascular events in the lowest tertile of sodium intake. Compared to non-RAASi, the trend in risk for renal events was significantly reduced by 43%, not changed, or increased by 37% for each tertile of increased sodium intake, respectively. The trend for cardiovascular events was significantly reduced by 37%, increased by 2% and 25%, respectively. Thus, treatment effects of ARB compared with non-RAASi-based therapy on renal and cardiovascular outcomes were greater in patients with type 2 diabetic nephropathy with lower than higher dietary sodium intake. This underscores the avoidance of excessive sodium intake, particularly in type 2 diabetic patients receiving ARB therapy.

  6. Deletion of the angiotensin II type 1 receptor–associated protein enhances renal sodium reabsorption and exacerbates angiotensin II–mediated hypertension

    OpenAIRE

    Ohsawa, Masato; Tamura, Kouichi; Wakui, Hiromichi; Maeda, Akinobu; Dejima, Toru; Kanaoka, Tomohiko; Azushima, Kengo; Uneda, Kazushi; Tsurumi-Ikeya, Yuko; Kobayashi, Ryu; Matsuda, Miyuki; Uchida, Shinichi; Toya, Yoshiyuki; Kobori, Hiroyuki; Nishiyama, Akira

    2014-01-01

    Angiotensin II type 1 receptor (AT1R)–associated protein (ATRAP) promotes AT1R internalization along with suppression of pathological activation of tissue AT1R signaling. However, the functional significance of ATRAP in renal sodium handling and blood pressure regulation under pathological stimuli is not fully resolved. Here we show the blood pressure of mice with a gene-targeted disruption of ATRAP was comparable to that of wild-type mice at baseline. However, in ATRAP-knockout mice, angiote...

  7. The angiotensin receptor blocker, Losartan, inhibits mammary tumor development and progression to invasive carcinoma

    Science.gov (United States)

    Coulson, Rhiannon; Liew, Seng H.; Connelly, Angela A.; Yee, Nicholas S.; Deb, Siddhartha; Kumar, Beena; Vargas, Ana C.; O’Toole, Sandra A.; Parslow, Adam C.; Poh, Ashleigh; Putoczki, Tracy; Morrow, Riley J.; Alorro, Mariah; Lazarus, Kyren A.; Yeap, Evie F.W.; Walton, Kelly L.; Harrison, Craig A.; Hannan, Natalie J.; George, Amee J.; Clyne, Colin D.; Ernst, Matthias; Allen, Andrew M.; Chand, Ashwini L.

    2017-01-01

    Drugs that target the Renin-Angiotensin System (RAS) have recently come into focus for their potential utility as cancer treatments. The use of Angiotensin Receptor Blockers (ARBs) and Angiotensin-Converting Enzyme (ACE) Inhibitors (ACEIs) to manage hypertension in cancer patients is correlated with improved survival outcomes for renal, prostate, breast and small cell lung cancer. Previous studies demonstrate that the Angiotensin Receptor Type I (AT1R) is linked to breast cancer pathogenesis, with unbiased analysis of gene-expression studies identifying significant up-regulation of AGTR1, the gene encoding AT1R in ER+ve/HER2−ve tumors correlating with poor prognosis. However, there is no evidence, so far, of the functional contribution of AT1R to breast tumorigenesis. We explored the potential therapeutic benefit of ARB in a carcinogen-induced mouse model of breast cancer and clarified the mechanisms associated with its success. Mammary tumors were induced with 7,12-dimethylbenz[α]antracene (DMBA) and medroxyprogesterone acetate (MPA) in female wild type mice and the effects of the ARB, Losartan treatment assessed in a preventative setting (n = 15 per group). Tumor histopathology was characterised by immunohistochemistry, real-time qPCR to detect gene expression signatures, and tumor cytokine levels measured with quantitative bioplex assays. AT1R was detected with radiolabelled ligand binding assays in fresh frozen tumor samples. We showed that therapeutic inhibition of AT1R, with Losartan, resulted in a significant reduction in tumor burden; and no mammary tumor incidence in 20% of animals. We observed a significant reduction in tumor progression from DCIS to invasive cancer with Losartan treatment. This was associated with reduced tumor cell proliferation and a significant reduction in IL-6, pSTAT3 and TNFα levels. Analysis of tumor immune cell infiltrates, however, demonstrated no significant differences in the recruitment of lymphocytes or tumour

  8. No significant effect of angiotensin II receptor blockade on intermediate cardiovascular end points in hemodialysis patients

    DEFF Research Database (Denmark)

    Peters, Christian D; Kjaergaard, Krista D; Jensen, Jens D;

    2014-01-01

    Agents blocking the renin-angiotensin-aldosterone system are frequently used in patients with end-stage renal disease, but whether they exert beneficial cardiovascular effects is unclear. Here the long-term effects of the angiotensin II receptor blocker, irbesartan, were studied in hemodialysis...... the study period significantly correlated with changes in both left ventricular mass and arterial stiffness. Thus, significant effects of irbesartan on intermediate cardiovascular end points beyond blood pressure reduction were absent in hemodialysis patients....

  9. New probes for angiotensin II receptors. Synthesis, radioiodination and biological properties of biotinylated and haptenated angiotensin derivatives.

    Science.gov (United States)

    Bonnafous, J C; Tence, M; Seyer, R; Marie, J; Aumelas, A; Jard, S

    1988-05-01

    The present work delineates the basis for chemical modifications which can be introduced on the angiotensin II (AII) molecule to design probes suitable for indirect affinity techniques, especially for receptor purification. Using the solid-phase synthesis strategy, biotin or dinitrophenyl moieties have been added at the N-terminus of AII, with aminohexanoic acid as spacer arm. The resulting probes, (6-biotinylamido)hexanoyl-AII (Bio-Ahx-AII) and dinitrophenylaminohexanoyl-AII (Dnp-Ahx-AII), were prepared in their monoiodinated and highly labelled radioiodinated forms, with possible sulphoxidation of biotin. In addition to their ability to interact with streptavidin and anti-Dnp antibodies respectively, the two ligands displayed almost unchanged affinities for hepatic AII receptors as compared with AII. Bio-Ahx-AII and Dnp-Ahx-AII behaved as agonists on several AII-sensitive systems. The potential applications of these probes, receptor purification, cell labelling and sorting and histochemical receptor visualization, are discussed.

  10. Angiotensin-2-mediated Ca2+ signaling in the retinal pigment epithelium: role of angiotensin-receptor-associated-protein and TRPV2 channel.

    Directory of Open Access Journals (Sweden)

    Rene Barro-Soria

    Full Text Available Angiotensin II (AngII receptor (ATR is involved in pathologic local events such as neovascularisation and inflammation including in the brain and retina. The retinal pigment epithelium (RPE expresses ATR in its AT1R form, angiotensin-receptor-associated protein (Atrap, and transient-receptor-potential channel-V2 (TRPV2. AT1R and Atrap co-localize to the basolateral membrane of the RPE, as shown by immunostaining. Stimulation of porcine RPE (pRPE cells by AngII results in biphasic increases in intracellular free Ca(2+inhibited by losartan. Xestospongin C (xest C and U-73122, blockers of IP3R and PLC respectively, reduced AngII-evoked Ca(2+response. RPE cells from Atrap(-/- mice showed smaller AngII-evoked Ca(2+peak (by 22% and loss of sustained Ca(2+elevation compared to wild-type. The TRPV channel activator cannabidiol (CBD at 15 µM stimulates intracellular Ca(2+-rise suggesting that porcine RPE cells express TRPV2 channels. Further evidence supporting the functional expression of TRPV2 channels comes from experiments in which 100 µM SKF96365 (a TRPV channel inhibitor reduced the cannabidiol-induced Ca(2+-rise. Application of SKF96365 or reduction of TRPV2 expression by siRNA reduced the sustained phase of AngII-mediated Ca(2+transients by 53%. Thus systemic AngII, an effector of the local renin-angiotensin system stimulates biphasic Ca(2+transients in the RPE by releasing Ca(2+from cytosolic IP3-dependent stores and activating ATR/Atrap and TRPV2 channels to generate a sustained Ca(2+elevation.

  11. Valsartan attenuates intimal hyperplasia in balloon-injured rat aortic arteries through modulating the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor axis.

    Science.gov (United States)

    Li, Yonghong; Cai, Shanglang; Wang, Qixin; Zhou, Jingwei; Hou, Bo; Yu, Haichu; Ge, Zhiming; Guan, Renyan; Liu, Xu

    2016-05-15

    The role of the Mas receptor in the activity of valsartan against intimal hyperplasia is unclear. Herein, we investigated the role of the angiotensin-converting enzyme 2 (ACE2)-angiotensin-(1-7)-Mas receptor axis on the activity of valsartan against intimal hyperplasiain balloon-injured rat aortic arteries. Wistar rats were randomized equally into the sham control group, injured group, and injured plus valsartan (20 mg/kg/d)-treated group. Valsartan significantly attenuated the vascular smooth muscle cell proliferation and intimal and medial thickening on days 14 and 28 after injury. The angiotensin-(1-7) levels as well as ACE2 and Mas receptor mRNA/protein expression were significantly decreased in the injured rats, compared to the uninjured rats; meanwhile, the angiotensin II level as well as the ACE and AT1 receptor mRNA/protein expression were increased (all P Mas receptor mRNA/protein expression but decreased the angiotensin II level, ACE and AT1 receptor mRNA/protein expression, as well as the p-ERK protein expression, compared to the injured group (all P Mas axis as well as inhibition of the ACE-angiotensin II-AT1 and p-ERK pathways. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. MAS receptors mediate vasoprotective and atheroprotective effects of candesartan upon the recovery of vascular angiotensin-converting enzyme 2-angiotensin-(1-7)-MAS axis functionality.

    Science.gov (United States)

    Pernomian, Larissa; do Prado, Alejandro F; Gomes, Mayara S; Pernomian, Laena; da Silva, Carlos H T P; Gerlach, Raquel F; de Oliveira, Ana M

    2015-10-05

    AT1 antagonists effectively prevent atherosclerosis since AT1 upregulation and angiotensin II-induced proinflammatory actions are critical to atherogenesis. Despite the classic mechanisms underlying the vasoprotective and atheroprotective actions of AT1 antagonists, the cross-talk between angiotensin-converting enzyme-angiotensin II-AT1 and angiotensin-converting enzyme 2-angiotensin-(1-7)-MAS axes suggests other mechanisms beyond AT1 blockage in such effects. For instance, angiotensin-converting enzyme 2 activity is inhibited by reactive oxygen species derived from AT1-mediated proinflammatory signaling. Since angiotensin-(1-7) promotes antiatherogenic effects, we hypothesized that the vasoprotective and atheroprotective effects of AT1 antagonists could result from their inhibitory effects on the AT1-mediated negative modulation of vascular angiotensin-converting enzyme 2-angiotensin-(1-7)-MAS axis functionality. Interestingly, our results showed that early atherosclerosis triggered in thoracic aorta from high cholesterol fed-Apolipoprotein E-deficient mice impairs angiotensin-converting enzyme 2-angiotensin-(1-7)-MAS axis functionality by a proinflammatory-redox AT1-mediated pathway. In such mechanism, AT1 activation leads to the aortic release of tumor necrosis factor-α, which stimulates NAD(P)H oxidase/Nox1-driven generation of superoxide and hydrogen peroxide. While hydrogen peroxide inhibits angiotensin-converting enzyme 2 activity, superoxide impairs MAS functionality. Candesartan treatment restored the functionality of angiotensin-converting enzyme 2-angiotensin-(1-7)-MAS axis by inhibiting the proinflammatory-redox AT1-mediated mechanism. Candesartan also promoted vasoprotective and atheroprotective effects that were mediated by MAS since A779 (MAS antagonist) co-treatment inhibited them. The role of MAS receptors as the final mediators of the vasoprotective and atheroprotective effects of candesartan was supported by the vascular actions of angiotensin

  13. Evidence that the angiotensin at 2-receptor agonist compound 21 is also a low affinity thromboxane TXA2-receptor antagonist

    DEFF Research Database (Denmark)

    Fredgart, M.; Leurgans, T.; Stenelo, M.;

    2015-01-01

    Objective: The objective of this study was to test whether Compound 21 (C21), a high-affinity, non-peptide angiotensinAT2-receptor agonist, is also an antagonist of thromboxane A2 (TXA2) receptors thus reducing both vasoconstriction and platelet aggregation. Design and method: Binding of C21 to t...

  14. Relationship between genetic polymorphism in angiotensin-converting enzyme,angiotensintype 1 receptor and hepatitis B-related liver cirrhosis%血管紧张素转换酶及血管紧张素Ⅱ1型受体基因多态性与乙型肝炎肝硬化的关系

    Institute of Scientific and Technical Information of China (English)

    薛建波; 林懋惺; 杨丽

    2009-01-01

    目的 研究血管紧张素转换酶(angiotensin-converting enzyme,ACE)及血管紧张素Ⅱ1型受体(angiotensinⅡtype 1 receptor,AT1R)基因多态性与乙型肝炎肝硬化之间的关联及其在乙型肝炎肝硬化的发生、发展中的作用.方法 采用聚合酶链反应(polymerase chain reaction,PCR)及限制性片段长度多态性分析(restriction fragment length polymorphism,RFLP)检测技术,对115例乙型肝炎肝硬化患者和136例正常人群中的ACE(第16个intron I/D基因)ATlR(3′-U TR 1166A/C)的基因多态性分布进行了检测.结果 在ACE intron I/D基因多态性中各基因型在乙型肝炎肝硬化患者与正常人群中的差异无统计学意义(P>0.05);在乙型肝炎肝硬化患者中ACEI/D基因型的分布在有无腹水组问的差异有统计学意义,有腹水组ACE D/D基因型的频率高于无腹水组(27.8%vs11.6%,P0.05).结论 ACE的intron D/D基因型对于乙型肝炎肝硬化是不利因素,它可能与肝硬化患者腹水的形成相关,并可促进肝硬化的进展;而AT1R的1166A/C基因位点的变异尚未显示其与肝硬化有关.

  15. Synthesis of a biotinylated, iodinatable, and photoactivatable probe for angiotensin receptors.

    Science.gov (United States)

    Seyer, R; Aumelas, A; Tence, M; Marie, J; Bonnafous, J C; Jard, S; Castro, B

    1989-09-01

    We propose here a biotinyl-aminohexanoyl-[Ala1, Phe(4N3)8]angiotensin II analog as a radioiodinatable and photoactivatable probe for covalent labeling, detection and isolation of angiotensin receptors. A combination of solid phase and minimum-protection segment-coupling strategy using hexafluorophosphate of (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium (BOP) as a coupling reagent is proposed for the synthesis of this probe. Optimized yields were obtained by HPLC monitoring of all reactions. A complete n.m.r. study suggests an extended conformation of this molecule, allowing a simultaneous recognition of receptor and avidin. The probe binds with high affinity (Kd = 2 nM) to angiotensin II receptors from rat liver membranes.

  16. Cardiac ACE2/angiotensin 1-7/Mas receptor axis is activated in thyroid hormone-induced cardiac hypertrophy.

    Science.gov (United States)

    Diniz, Gabriela P; Senger, Nathalia; Carneiro-Ramos, Marcela S; Santos, Robson A S; Barreto-Chaves, Maria Luiza M

    2016-08-01

    Thyroid hormone (TH) promotes marked effects on the cardiovascular system, including the development of cardiac hypertrophy. Some studies have demonstrated that the renin-angiotensin system (RAS) is a key mediator of the cardiac growth in response to elevated TH levels. Although some of the main RAS components are changed in cardiac tissue on hyperthyroid state, the potential modulation of the counter regulatory components of the RAS, such as angiotensin-converting enzyme type 2 (ACE2), angiotensin 1-7 (Ang 1-7) levels and Mas receptor induced by hyperthyroidism is unknown. The aim of this study was to investigate the effect of hyperthyroidism on cardiac Ang 1-7, ACE2 and Mas receptor levels. Hyperthyroidism was induced in Wistar rats by daily intraperitoneal injections of T4 for 14 days. Although plasma Ang 1-7 levels were unchanged by hyperthyroidism, cardiac Ang 1-7 levels were increased in TH-induced cardiac hypertrophy. ACE2 enzymatic activity was significantly increased in hearts from hyperthyroid animals, which may be contributing to the higher Ang 1-7 levels observed in the T4 group. Furthermore, elevated cardiac levels of Ang 1-7 levels were accompanied by increased Mas receptor protein levels. The counter-regulatory components of the RAS are activated in hyperthyroidism and may be contributing to modulate the cardiac hypertrophy in response to TH. © The Author(s), 2015.

  17. Inhibitory effect of angiotensin TT receptor antagonist on hepatic stellate cell activation in non-alcoholic steatohepatitis

    Institute of Scientific and Technical Information of China (English)

    Shiro Yokohama; Naoyuki Miyokawa; Masakazu Haneda; Masashi Yoneda; Yoshihiko Tokusashi; Kimihide Nakamura; Yosui Tamaki; Satoshi Okamoto; Mituyoshi Okada; Kazunobu Aso; Takenao Hasegawa; Masaru Aoshima

    2006-01-01

    AIM: To investigate the efficacy of angiotensinreceptor antagonist on hepatic stellate cells (HSCs) activation in the patients with non-alcoholic steatohepatitis (NASH).METHODS: Seven patients with NASH were prescribed losartan, a selective angiotensintype 1 receptor antagonist (50 mg/d) for 48 wk. Liver biopsies were performed both at the entry and end of the study in all patients. Quiescent and activated HSCs were identified by double immunostaining using anti-p75 and α-smooth muscle actin antibodies, and the number of each phenotype was counted. Similarly, the liver specimens obtained from the eight patients with non-alcoholic fatty liver (NAFL) were also examined as controls.RESULTS: In NASH hepatic tissues, activated HSCs were dominantly distributed as compared with those in NAFL.The 48-wk losartan treatment induced a remarkable decrease in activated HSCs and a mild increase in quiescent phenotypes.CONCLUSION: Our data suggest the crucial involvement of HSCs in anti-fibrotic effect of angiotensinreceptor antagonist on patients with NASH.

  18. Genetic and dietary interactions: role of angiotensin AT1a receptors in response to a high-fructose diet.

    Science.gov (United States)

    Farah, Vera; Elased, Khalid M; Morris, Mariana

    2007-08-01

    The renin-angiotensin system (RAS) has been implicated in the cardiovascular complications of diabetes. We showed that a high-fructose diet increases blood pressure and plasma angiotensin and impairs glucose tolerance. We investigated the role of angiotensin AT(1a) receptors in the development of fructose-induced cardiovascular and metabolic dysfunction. Male angiotensin AT(1a) knockout (AT1aKO) and wild-type (AT1aWT) mice with arterial telemetric catheters were fed a standard diet or one containing 60% fructose. Fructose increased mean arterial pressure (MAP) in AT1aWT but only during the dark phase (8% increase). In AT1aKO mice, fructose unexpectedly decreased MAP, during both light and dark periods (24 and 13% decrease, respectively). Analytical methods were used to measure systolic arterial pressure (SAP) and pulse interval (PI) variability in time and frequency domains. In fructose-fed AT1aWT mice, there was an increase in SAP variance and its low-frequency (LF) domain (11 +/- 3 vs. 23 +/- 4 mmHg(2), variance, and 7 +/- 2 vs. 17 +/- 3 mmHg(2), LF, control vs. fructose, P fructose-fed AT1a WT compared with AT1aKO mice. Fructose inhibited glucose tolerance with a greater effect in AT1aWT mice. Fructose increased plasma cholesterol in both groups (P fructose diet decreased blood pressure.

  19. Angiotensin II activates endothelial constitutive nitric oxide synthase via AT1 receptors.

    Science.gov (United States)

    Saito, S; Hirata, Y; Emori, T; Imai, T; Marumo, F

    1996-09-01

    To determine whether angiotensin (ANG) II, a vasoconstrictor hormone, activates constitutive nitric oxide synthase (cNOS) in endothelial cells (ECs), we investigated the cellular mechanism by which ANG II induces nitric oxide (NO) formation in cultured bovine ECs. ANG II rapidly (within 1 min) and dose-dependently (10(-9)-10(-6) M) increased nitrate/nitrite (NOx) production. This effect of ANG II was abolished by a NOS inhibitor, NG-monomethyl-L-arginine. An ANG II type 1 (AT1) receptor antagonist (DuP 753), but not an ANG II type 2 (AT2) receptor antagonist (PD 123177), dose-dependently inhibited ANG II-induced NOx production. A Ca(2+)-channel blocker (barnidipine) failed to affect ANG II-induced NOx production, whereas an intracellular Ca2+ chelator (BAPTA) and a calmodulin inhibitor (W-7) abolished NOx production induced by ANG II. A protein kinase C (PKC) inhibitor (H-7) and down-regulation of endogenous PKC after pretreatment with phorbol ester decreased NOx production stimulated by ANG II. ANG II transiently stimulated inositol 1,4,5-trisphosphate (IP3) formation, and increased cytosolic free Ca2+ concentrations; these effects were blocked by DuP 753. Our data demonstrate that ANG II stimulates NO release by activation of Ca2+/calmodulin-dependent cNOS via AT1 receptors in bovine ECs.

  20. 血管紧张素Ⅱ1型受体基因多态性与原发性高血压的关系%Association of angiotensintype 1 receptor gene polymorphism with essential hypertension

    Institute of Scientific and Technical Information of China (English)

    龚洪涛; 杜凤和

    2010-01-01

    Objective To investigate whether angiotensintype 1 receptor(AT1R)gene polymorphism is associated with essential hypertension(EH). Methods A total of 200 hypertension patients and 192 normotensive controls were enrolled. The AT1R gene 1166A/C and -810A/T polymorphism were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-PFLP), and the association between the SNPs and the EH were analyzed statistically. Some biochemical index such as serum glucose (GLU) and total cholesterol (TC),triglyceride (TG), high density lipoprotein (HDL-C) and low density lipoprotein (LDL-C) were also measured. Results There was no significant difference between two groups of 1166A/C polymorphisms of AT1R gene(P > 0.05 ). However, for the -810A/T polymorphism of AT1R gene, -810 AT and TT genotypes frequencies were significantly higher in EH patients than control (P = 0. 004). The -810T allele frequencies were higher in case than in control (22.5% vs. 11.5% ;P =0.000). We also found an association between EH and -810AT and TT genotypes by logistic regression analysis ( P = 0. 003 ), adjusted for other risk factors. The odds ratio was 2.57 (95% CI:1. 37 ~4. 84). Conclusions AT1R -810A/T polymorphism is associated with EH and -810T allele may be a risk factor of hypertension%目的 探讨血管紧张素Ⅱ1型受体(AT1R)基因多态性与原发性高血压(EH)之间的关系.方法 应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)对200例汉族EH患者(EH组)和192例正常血压者(对照组)的AT1R基因1166A/C及-810A/T多态性进行检测,测定空腹血糖、甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)及高密度脂蛋白胆固醇(HDL-C)等生物化学指标,分析各基因型和等位基因频率与EH的关系.结果 1166A/C等位基因和基因型频率在EH组和对照组的分布无统计学差异(P均>0.05),-810A/T各基因型在EH组和对照组间差异有统计学意义(x2=10.862,P=0

  1. Brain angiotensin AT1 receptors as specific regulators of cardiovascular reactivity to acute psychoemotional stress.

    Science.gov (United States)

    Mayorov, Dmitry N

    2011-02-01

    1. Cardiovascular reactivity, an abrupt rise in blood pressure (BP) and heart rate in response to psychoemotional stress, is a risk factor for heart disease. Pharmacological and molecular genetic studies suggest that brain angiotensin (Ang) II and AT(1) receptors are required for the normal expression of sympathetic cardiovascular responses to various psychological stressors. Moreover, overactivity of the brain AngII system may contribute to enhanced cardiovascular reactivity in hypertension. 2. Conversely, brain AT(1) receptors appear to be less important for the regulation of sympathetic cardiovascular responses to a range of stressors involving an immediate physiological threat (physical stressors) in animal models. 3. Apart from threatening events, appetitive stimuli can induce a distinct, central nervous system-mediated rise in BP. However, evidence indicates that brain AT(1) receptors are not essential for the regulation of cardiovascular arousal associated with positively motivated behaviour, such as anticipation and the consumption of palatable food. The role of central AT(1) receptors in regulating cardiovascular activation elicited by other types of appetitive stimuli remains to be determined. 4. Emerging evidence also indicates that brain AT(1) receptors play a limited role in the regulation of cardiovascular responses to non-emotional natural daily activities, sleep and exercise. 5. Collectively, these findings suggest that, with respect to cardiovascular arousal, central AT(1) receptors may be involved primarily in the regulation of the defence response. Therefore, these receptors could be a potential therapeutic target for selective attenuation of BP hyperreactivity to aversive stressors, without altering physiologically important cardiovascular adjustments to normal daily activities, sleep and exercise.

  2. Angiotensin AT1 receptors in Clone 9 rat liver cells: Ca2+ signaling and c-fos expression.

    Science.gov (United States)

    García-Sáinz, J A; García-Caballero, A; González-Espinosa, C

    1998-12-04

    In C9 (Clone 9) liver cells, angiotensin 11 increased the intracellular Ca2+ content, inositol phosphate production and c-fos mRNA expression. Other angiotensins were also active with the order of potency being angiotensin II = angiotensin III > angiotensin I > angiotensin IV. Losartan, but not PD 123177 (1-(4-amino-3-methyl)-5-diphenylacetyl-4,5,6,7-tetrahydro-1H-imida zo [4,5c]pyridine-6-carboxylic acid), blocked the effects of angiotensin II. Pertussis toxin did not alter these actions of angiotensin II. These data indicate that the effects were mediated through angiotensin AT1 receptors involving pertussis toxin-insensitive G-proteins. Phorbol myristate acetate was also able to increase c-fos mRNA expression. The action of angiotensin II was consistently greater than that of the active phorbol ester. Staurosporine but not genistein inhibited this effect of angiotensin II. Angiotensin II- and phorbol myristate acetate-induced proto-oncogene mRNA expression was attenuated in cells incubated overnight with the active phorbol ester, which suggests a major role of protein kinase C.

  3. Intrarenal alterations of the angiotensin-converting enzyme type 2/angiotensin 1-7 complex of the renin-angiotensin system do not alter the course of malignant hypertension in Cyp1a1-Ren-2 transgenic rats.

    Science.gov (United States)

    Husková, Zuzana; Kopkan, Libor; Červenková, Lenka; Doleželová, Šárka; Vaňourková, Zdeňka; Škaroupková, Petra; Nishiyama, Akira; Kompanowska-Jezierska, Elzbieta; Sadowski, Janusz; Kramer, Herbert J; Červenka, Luděk

    2016-04-01

    The role of the intrarenal renin-angiotensin system (RAS) in the pathophysiology of malignant hypertension is not fully understood. Accumulating evidence indicates that the recently discovered vasodilator axis of the RAS, angiotensin-converting enzyme (ACE) type 2 (ACE2)/angiotensin 1-7 (ANG 1-7), constitutes an endogenous system counterbalancing the hypertensiogenic axis, ACE/angiotensin II (ANG II)/AT1 receptor. This study aimed to evaluate the role of the intrarenal vasodilator RAS axis in the pathophysiology of ANG II-dependent malignant hypertension in Cyp1a1-Ren-2 transgenic rats. ANG II-dependent malignant hypertension was induced by 13 days' dietary administration of indole-3-carbinol (I3C), a natural xenobiotic that activates the mouse renin gene in Cyp1a1-Ren-2 transgenic rats. It was hypothesized that pharmacologically-induced inhibition of the ACE2/ANG 1-7 complex should aggravate, and activation of this axis should attenuate, the course of ANG II-dependent malignant hypertension. Blood pressure (BP) was monitored by radiotelemetry. ACE2 inhibitor (DX 600, 0.2 μg/day) and ACE2 activator (DIZE, 1 mg/day) were administrated via osmotic minipumps. Even though ACE2 inhibitor significantly decreased and ACE2 activator increased intrarenal ANG 1-7 concentrations, the course of BP, as well as of albuminuria, cardiac hypertrophy and renal glomerular damage, were not altered. It was shown that intrarenal alterations in the ACE2/ANG 1-7 complex did not significantly modify the course of malignant hypertension in I3C-induced Cyp1a1-Ren-2 transgenic rats. Thus, in our experimental setting alterations of this intrarenal vasodilator complex of the RAS do not significantly modify the form of malignant hypertension that clearly depends on the inappropriately increased activity of the ACE/ANG II/AT1 receptor axis.

  4. Advance in Research of Angiotensin II and Its Receptor and Malignant Tumor

    Directory of Open Access Journals (Sweden)

    Lulu SUN

    2016-09-01

    Full Text Available Angiotensin AngII, a linear small peptide,which is composed of eight amino acids, is the main effectors of renin-angiotensin systen (Renin-angiotensin system, RAS. AngII, a main biopolypeptide of the RAS, has important pathophysiologic in effects participating in cardiac hypertrophy, vascular cell proproliferation, inflammation and tissue remodeling through G-protein-coupled receptors. In recent years, Ang II can promote tumor cell proliferation, tumor vessel formation and inhibit the differentiation of the tumor cells. This suggests that inhibit the production of AngII or block its effect is expected to become a new measure for the treatment of malignant tumors. This article reviews the advances in research on the relationship between AngII and its receptor and malignant tumor in recent years.

  5. Molecular targeting therapy with angiotensin II receptor blocker for prostatic cancer

    Directory of Open Access Journals (Sweden)

    Hiroji Uemura

    2011-12-01

    Full Text Available Angiotensin II (Ang-II plays a key role as a vasoconstrictor in controlling blood pressure and electrolyte/fluid homeostasis. Recently it has also been shown that this peptide is a cytokine, acting as a growth factor in cardiovascular and stromal cells. In addition, the physiological function of Ang-II seems to be similar in prostate cancer and stromal cells. It is widely assumed that Ang-II facilitates the growth of both cells, and its receptor blockers (ARBs have the potential to inhibit the growth of various cancer cells and tumors through the Ang-II receptor type 1 (AT1 receptor. The mechanism of cell growth inhibition by ARBs has been considered to be that of suppression of the signal transduction systems activated by growth factors or cytokines in prostate cancer cells, and suppression of angiogenesis. This review highlights the possible use of ARBs as novel agents for prostatic diseases including prostate cancer and benign hypertrophy, and covers related literature.

  6. Molecular targeting therapy with angiotensin II receptor blocker for prostatic cancer

    Directory of Open Access Journals (Sweden)

    Hiroji Uemura

    2011-12-01

    Full Text Available Angiotensin II (Ang-II plays a key role as a vasoconstrictor in controlling blood pressure and electrolyte/fluid homeostasis. Recently it has also been shown that this peptide is a cytokine, acting as a growth factor in cardiovascular and stromal cells. In addition, the physiological function of Ang-II seems to be similar in prostate cancer and stromal cells. It is widely assumed that Ang-II facilitates the growth of both cells, and its receptor blockers (ARBs have the potential to inhibit the growth of various cancer cells and tumors through the Ang-II receptor type 1 (AT1 receptor. The mechanism of cell growth inhibition by ARBs has been considered to be that of suppression of the signal transduction systems activated by growth factors or cytokines in prostate cancer cells, and suppression of angiogenesis. This review highlights the possible use of ARBs as novel agents for prostatic diseases including prostate cancer and benign hypertrophy, and covers related literature.

  7. Moderation of dietary sodium potentiates the renal and cardiovascular protective effects of angiotensin receptor blockers

    NARCIS (Netherlands)

    Lambers Heerspink, Hiddo J.; Holtkamp, Frank A.; Parving, Hans-Henrik; Navis, Gerjan J.; Lewis, Julia B.; Ritz, Eberhard; de Graeff, Pieter A.; de Zeeuw, Dick

    2012-01-01

    Dietary sodium restriction has been shown to enhance the short-term response of blood pressure and albuminuria to angiotensin receptor blockers (ARBs). Whether this also enhances the long-term renal and cardiovascular protective effects of ARBs is unknown. Here we conducted a post-hoc analysis of th

  8. Interaction of a non-peptide agonist with angiotensin II AT1 receptor mutants

    DEFF Research Database (Denmark)

    Costa-Neto, Claudio M; Miyakawa, Ayumi A; Pesquero, João B;

    2002-01-01

    To identify residues of the rat AT1A angiotensin II receptor involved with signal transduction and binding of the non-peptide agonist L-162,313 (5,7-dimethyl-2-ethyl-3-[[4-[2(n-butyloxycarbonylsulfonamido)-5-isobutyl-3-thienyl]phenyl]methyl]imidazol[4,5,6]-pyridine) we have performed ligand bindi...

  9. Moderation of dietary sodium potentiates the renal and cardiovascular protective effects of angiotensin receptor blockers

    NARCIS (Netherlands)

    Lambers Heerspink, Hiddo J.; Holtkamp, Frank A.; Parving, Hans-Henrik; Navis, Gerjan J.; Lewis, Julia B.; Ritz, Eberhard; de Graeff, Pieter A.; de Zeeuw, Dick

    2012-01-01

    Dietary sodium restriction has been shown to enhance the short-term response of blood pressure and albuminuria to angiotensin receptor blockers (ARBs). Whether this also enhances the long-term renal and cardiovascular protective effects of ARBs is unknown. Here we conducted a post-hoc analysis of th

  10. Uptake of angiotensin II receptor blockers in the treatment of hypertension

    NARCIS (Netherlands)

    Greving, JP; Denig, P; van der Veen, WJ; Beltman, FW; Sturkenboom, MCJM; de Zeeuw, D; Haaijer-Ruskamp, FM

    2005-01-01

    Objective: To examine trends in prescribing of angiotensin II receptor blockers (ARBs) as initial and second-line treatment of hypertension. Methods: We performed a cohort study in the Integrated Primary Care Information database, a general practice research database in The Netherlands. We included

  11. Moderation of dietary sodium potentiates the renal and cardiovascular protective effects of angiotensin receptor blockers

    NARCIS (Netherlands)

    Lambers Heerspink, Hiddo J.; Holtkamp, Frank A.; Parving, Hans-Henrik; Navis, Gerjan J.; Lewis, Julia B.; Ritz, Eberhard; de Graeff, Pieter A.; de Zeeuw, Dick

    Dietary sodium restriction has been shown to enhance the short-term response of blood pressure and albuminuria to angiotensin receptor blockers (ARBs). Whether this also enhances the long-term renal and cardiovascular protective effects of ARBs is unknown. Here we conducted a post-hoc analysis of

  12. Comparison of the antagonistic effects of different angiotensin II receptor blockers in human coronary arteries

    DEFF Research Database (Denmark)

    Pantev, Emil; Stenman, Emelie; Wackenfors, Angelica;

    2002-01-01

    BACKGROUND: Angiotensin II (Ang II) is a potent vasoconstrictor and a deleterious factor in cardiovascular pathophysiology. Ang II receptor blockers (ARBs) have recently been introduced into clinical practice for treatment of hypertension and congestive heart failure. AIMS: This study was underta...

  13. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in patients with abdominal aortic aneurysms: nation-wide cohort study.

    Science.gov (United States)

    Kristensen, Karl Emil; Torp-Pedersen, Christian; Gislason, Gunnar Hilmar; Egfjord, Martin; Rasmussen, Henrik Berg; Hansen, Peter Riis

    2015-03-01

    The renin-angiotensin system is thought to play a pivotal role in the pathogenesis of abdominal aortic aneurysms (AAAs). However, effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) on human AAAs remain unclear. We therefore examined whether treatment with ACEIs or ARBs influenced hard clinical end points in a nation-wide cohort of patients with AAA. All patients diagnosed with AAA during the period 1995 to 2011 were identified from the Danish nation-wide registries. Subjects were divided according to ACEI and ARB treatment status and followed up for an average of 5 years. Study outcomes were evaluated by time-dependent Cox proportional hazard models. Of 9441 patients with AAA, 12.6% were treated with ACEIs and 5.0% received ARBs. Incidence rates of death from AAA per 100 patient-years were 3.7, 3.6, 4.0, and 4.7 for treatment with ACEIs or ARBs, ACEIs, ARBs, and no ACEI/ARB, respectively. Hazard ratios of death from AAA were 0.64 (95% confidence interval, 0.51-0.80; PACEIs and 0.65 (95% confidence interval, 0.48-0.88; P=0.006) for those receiving ARBs, respectively (P for difference=0.944). The risk of surgery for AAA was significantly reduced in patients receiving ACEIs (hazard ratio, 0.86 [95% confidence interval, 0.74-0.99]; P=0.040) but not in patients receiving ARBs (hazard ratio, 1.02 [95% confidence interval, 0.84-1.23]; P=0.867; P for difference=0.119). In this observational study, treatment with ACEIs or ARBs was associated with a comparable reduction in mortality but not in surgery for AAA among patients with AAA. Randomized controlled trials are warranted to confirm these findings. © 2015 American Heart Association, Inc.

  14. An ATIPical family of angiotensin II AT2 receptor-interacting proteins.

    Science.gov (United States)

    Rodrigues-Ferreira, Sylvie; Nahmias, Clara

    2010-11-01

    AT2, the second subtype of angiotensin II receptors, is a major component of the renin-angiotensin system involved in cardiovascular and neuronal functions. AT2 belongs to the superfamily of G protein-coupled receptors, but its intracellular signaling pathways have long remained elusive. Over the past few years, efforts to characterize this atypical receptor have led to the identification of novel molecular scaffolds that directly bind to its intracellular tail. The present review focuses on a family of AT2 receptor-interacting proteins (ATIPs) involved in neuronal differentiation, vascular remodeling and tumor suppression. Recent findings that ATIPs and ATIP-related proteins associate with microtubules suggest that they might constitute a novel family of multifunctional proteins regulating a wide range of physiopathological functions.

  15. Effects of Spironolactone in Combination with Angiotensin-Converting Enzyme Inhibitors or Angiotensin Receptor Blockers in Patients with Proteinuria

    Directory of Open Access Journals (Sweden)

    Ha Yeon Kim

    2014-12-01

    Full Text Available Background/Aims: This study aimed to investigate the potential beneficial anti-proteinuric effect of an add-on aldosterone blockade and the impact of the aldosterone escape phenomenon. Methods: We retrospectively analyzed data of 304 patients with persistent proteinuria, who were administered spironolactone (25 mg/day after treatment with angiotensin-converting enzyme inhibitors (ACEIs or angiotensin II receptor blockers (ARBs for >3 months. Patients were divided according to their aldosterone levels during ACEI/ARB treatment into an escape group (plasma aldosterone >80 pg/mL, N=95, 31.5% and a non-escape group (plasma aldosterone ≤80 pg/mL, N=209, 68.5% and according to their urine albumin-to-creatinine ratio (UACR and estimated glomerular filtration rate (eGFR. Results: After 12 months, the UACR decreased significantly in patients with 1≤UACR2, and in the non-escape group. Severe hyperkalemia (K≥7.0 mEq/L developed in 9 of 137 patients with eGFR2 (6.5% and in none of the 167 patients with eGFR≥60 mL/min/1.73 m2. Conclusions: Proteinuria decreased significantly after add-on spironolactone treatment in patients with 1≤UACR2, and in the non-escape group. The anti-proteinuric effect of spironolactone may vary according to the degree of albuminuria, impaired eGFR, and aldosterone escape.

  16. Hyperkalemia of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in hemodialysis: a meta-analysis.

    Science.gov (United States)

    Zhang, Qian; Luan, Hong; Wang, Le; Zhang, Miao; Chen, Yan; Lv, Yongman; Ma, Zufu

    2012-10-01

    The safety of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) used in hemodialysis (HD) patients was evaluated. Medline, Embase, the Cochrane Library, some databases of clinical trial registries, grey literatures, other reference lists of eligible articles and review articles for the randomized clinical trials (RCTs) on comparison of ACEIs/ARBs or placebo in HD patients were retrieved. RCTs reporting the risk of hyperkalemia by using ACEIs/ARBs in HD patients were selected. Eight articles met the eligibility criteria and were subjected to meta-analysis by using the Cochrane Collaboration's RevMan 4.2 software package. The results showed that there was no significant difference in hyperkalemia in HD patients between ACEIs or ARBs group and control group (ACEIs vs. control: RD=0.03, 95% CI=-0.13-0.18, Z=0.34, P=0.73; ARBs vs. control: RD=-0.02, 95% CI=-0.07-0.03, Z=0.75, P=0.45). However, there was no significant difference in the serum potassium between ACEIs or ARBs group and control group in HD patients (ACEIs vs. control: WMD=0.10, 95% CI=0.06-0.15, Z=4.64, PACEIs or ARBs could not cause an increased risk of hyperkalemia in HD patients, however the serum potassium could be increased with use of ACEIs in HD patients. Therefore the serum potassium concentration should still be closely monitored when ACEIs are taken during the maintenance HD.

  17. Renoprotective Effect of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers in Diabetic Patients with Proteinuria

    Directory of Open Access Journals (Sweden)

    Feng-Yi Hsu

    2017-06-01

    Full Text Available Background/Aims: Limited evidence exists on the choice of angiotensin-converting enzyme inhibitors (ACEIs and angiotensin II receptor blockers (ARBs in diabetic patients with nephropathy. We aim to assess the renal effectiveness and safety of these drugs among diabetic nephropathy patients. Methods: This retrospective cohort study was conducted with diabetic nephropathy patients who initiated ACEI or ARB monotherapy. The primary outcome was a composite of end stage of renal disease and renal transplantation, and the secondary outcome was all-cause mortality. The safety endpoint was hyperkalemia. Results: Three thousand seven hundred and thirty-nine ACEI users and 3,316 ARB users were identified. ARBs seemed to be inferior to ACEIs given their poorer renal outcome (HR 1.31; 95% CI, 1.15-1.50 and higher risk of hyperkalemia (HR 1.17; 95% CI, 1.04-1.32. Among the four ACEIs compared, captopril was an inferior treatment choice given its poorer renal outcomes (HR 1.42; 95% CI, 1.05-1.93 and higher mortality rate (HR 1.25; 95% CI, 1.01-1.55. Irbesartan appeared to be a poorer treatment choice among the three ARBs compared, given its inferior renal protective effect (HR 1.35; 95% CI, 1.03-1.78. Conclusions: Our findings suggest ACEIs as a relatively more renoprotective and safer treatment as compared to ARBs. Captopril and irbesartan may be inferior to the other ACEIs and ARBs respectively.

  18. Transdermal delivery of angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs) and others for management of hypertension.

    Science.gov (United States)

    Ahad, Abdul; Al-Mohizea, Abdullah Mohammed; Al-Jenoobi, Fahad Ibrahim; Aqil, Mohd

    2016-01-01

    Angiotensin II receptor blockers (ARBs), angiotensin-converting enzyme inhibitors (ACEIs) are some of the most commonly prescribed medications for hypertension. Most of all conventional dosage forms of ARBs and ACEIs undergo extensive first-pass metabolism, which significantly reduces bioavailability. Majority of ARBs and ACEIs are inherently short acting due to a rapid elimination half-life. In addition, oral dosage forms of ARBs and ACEIs have many high incidences of adverse effects due to variable absorption profiles, higher frequency of administration and poor patient compliance. Many attempts have been made globally at the laboratory level to investigate the skin permeation and to develop transdermal therapeutic systems of various ARBs, ACEIs and other anti-hypertensives, to circumvent the drawbacks associated with their conventional dosage form. This manuscript presents an outline of the transdermal research specifically in the area of ARBs, ACEIs and other anti-hypertensives reported in various pharmaceutical journals. The transdermal delivery has gained a significant importance for systemic treatment as it is able to avoid first-pass metabolism and major fluctuations of plasma levels typical of repeated oral administration. As we can experience from this review article that transdermal delivery of different ARBs and ACEIs improves bioavailability as well as patient compliance by many folds. In fact, the rationale development of some newer ARBs, ACEIs and other anti-hypertensives transdermal systems will provide new ways of treatment, circumventing current limitations for conventional dosage forms.

  19. Renoprotective Effect of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers in Diabetic Patients with Proteinuria.

    Science.gov (United States)

    Hsu, Feng-Yi; Lin, Fang-Ju; Ou, Huang-Tz; Huang, Shih-Hui; Wang, Chi-Chuan

    2017-01-01

    Limited evidence exists on the choice of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) in diabetic patients with nephropathy. We aim to assess the renal effectiveness and safety of these drugs among diabetic nephropathy patients. This retrospective cohort study was conducted with diabetic nephropathy patients who initiated ACEI or ARB monotherapy. The primary outcome was a composite of end stage of renal disease and renal transplantation, and the secondary outcome was all-cause mortality. The safety endpoint was hyperkalemia. Three thousand seven hundred and thirty-nine ACEI users and 3,316 ARB users were identified. ARBs seemed to be inferior to ACEIs given their poorer renal outcome (HR 1.31; 95% CI, 1.15-1.50) and higher risk of hyperkalemia (HR 1.17; 95% CI, 1.04-1.32). Among the four ACEIs compared, captopril was an inferior treatment choice given its poorer renal outcomes (HR 1.42; 95% CI, 1.05-1.93) and higher mortality rate (HR 1.25; 95% CI, 1.01-1.55). Irbesartan appeared to be a poorer treatment choice among the three ARBs compared, given its inferior renal protective effect (HR 1.35; 95% CI, 1.03-1.78). Our findings suggest ACEIs as a relatively more renoprotective and safer treatment as compared to ARBs. Captopril and irbesartan may be inferior to the other ACEIs and ARBs respectively. © 2017 The Author(s). Published by S. Karger AG, Basel.

  20. Dual targeting of angiotensin receptors (AGTR1 and AGTR2) in epithelial ovarian carcinoma.

    Science.gov (United States)

    Park, Young-Ae; Choi, Chel Hun; Do, In-Gu; Song, Sang Yong; Lee, Jae Kwan; Cho, Young Jae; Choi, Jung-Joo; Jeon, Hye Kyung; Ryu, Ji Yoon; Lee, Yoo-Young; Kim, Tae-Joong; Bae, Duk-Soo; Lee, Jeong-Won; Kim, Byoung-Gie

    2014-10-01

    The renin-angiotensin system (RAS) influences cardiovascular homeostasis, and Angiotensin II type 1 receptor (AGTR1) is the main effector of RAS, and AGTR2 antagonizes AGTR1. Accumulating evidence supports the role of RAS in the paracrine regulation of tumorigenesis in several cancer types. Although treatment with AGTR1 antagonist (losartan) or AGTR2 agonist (CGP42112A) inhibits tumor progression in several cancer cells, their combined treatment has not been reported. In this study, we estimated the expression of AGTR1 and AGTR2 in epithelial ovarian cancer cells and tissues. Then, we evaluated the anti-cancer effects of combined treatment with losartan and/or CGP42112A in ovarian cancer cells and human umbilical vein endothelial cells (HUVEC). AGTR1 protein was detected in 86% of ovarian cancer tissues, while AGTR2 was not detected in immunohistochemistry. The mRNA expression of AGTR1 obtained from the cancer genome atlas (TCGA) dataset showed that AGTR1 overexpression was correlated with poor survival. Treatment with either losartan or CGP42112A reduced the angiotensin II (Ang II)-mediated cell survival in both ovarian cancer cells and HUVEC. Combined treatment with losartan and CGP42112A synergistically decreased cell survival. As a downstream pathway, phosphorylation of phospholipase C β3 (PLC β3) and expression of vascular endothelial growth factor (VEGF) decreased synergistically in combined treatment. The results suggest that dual regulation of AGTR1 and AGTR2 may be a novel therapeutic strategy for epithelial ovarian carcinoma through inhibition of cancer cell survival as well as anti-angiogenesis. This study investigated the expressions of AGTR1 and AGTR2 in epithelial ovarian carcinoma and the therapeutic potential of AGTR modulation with specific antagonist and/or agonist in epithelial ovarian cancer cells. Treatment of AGTR1 antagonist, losartan and/or AGTR2 agonist, CGP42112A synergistically mediated anti-cancer effects including the decrease of cell

  1. Angiotensin receptor-neprilysin inhibitors: clinical potential in heart failure and beyond

    Directory of Open Access Journals (Sweden)

    Singh JSS

    2015-06-01

    Full Text Available Jagdeep SS Singh, Chim C Lang Division of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK Abstract: Heart failure remains a major concern across the globe as life expectancies and delivery of health care continue to improve. There has been a dearth of new developments in heart failure therapies in the last decade until last year, with the release of the results from the PARADIGM-HF Trial heralding the arrival of a promising new class of drug, ie, the angiotensin receptor-neprilysin inhibitor. In this review, we discuss the evolution of our incremental understanding of the neurohormonal mechanisms involved in the pathophysiology of heart failure, which has led to our success in modulating its various pathways. We start by examining the renin-angiotensin-aldosterone system, followed by the challenges of modulating the natriuretic peptide system. We then delve deeper into the pharmacology and mechanisms by which angiotensin receptor-neprilysin inhibitors achieve their significant cardiovascular benefits. Finally, we also consider the potential application of this new class of drug in other areas, such as heart failure with preserved ejection fraction, hypertension, patients with renal impairment, and following myocardial infarction. Keywords: heart failure, angiotensin receptor-neprilysin inhibitor, heart failure with preserved ejection fraction, nesiritide, candoxatril, omapatrilat, hypertension, renal impairment, myocardial infarction

  2. Severe hepatic encephalopathy in a patient with liver cirrhosis after administration of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker combination therapy: a case report

    Directory of Open Access Journals (Sweden)

    Podda Mauro

    2010-05-01

    Full Text Available Abstract Introduction A combination therapy of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers has been used to control proteinuria, following initial demonstration of its efficacy. However, recently concerns about the safety of this therapy have emerged, prompting several authors to urge for caution in its use. In the following case report, we describe the occurrence of a serious and unexpected adverse drug reaction after administration of a combination of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers to a patient with nephrotic syndrome and liver cirrhosis with severe portal hypertension. Case presentation We administered this combination therapy to a 40-year-old Caucasian man with liver cirrhosis in our Hepatology Clinic, given the concomitant presence of glomerulopathy associated with severe proteinuria. While the administration of one single drug appeared to be well-tolerated, our patient developed severe acute encephalopathy after the addition of the second one. Discontinuation of the therapy led to the disappearance of the side-effect. A tentative rechallenge with the same drug combination led to a second episode of acute severe encephalopathy. Conclusion We speculate that this adverse reaction may be directly related to the effect of angiotensin II on the excretion of blood ammonia. Therefore, we suggest that patients with liver cirrhosis and portal hypertension are at risk of developing clinically relevant encephalopathy when angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker combination therapy is administered, thus indicating the need for a careful clinical follow-up. In addition, the incidence of this serious side-effect should be rigorously evaluated in all patients with liver cirrhosis administered with this common treatment combination.

  3. Long-term use of angiotensin receptor blockers and the risk of cancer.

    Directory of Open Access Journals (Sweden)

    Laurent Azoulay

    Full Text Available The association between angiotensin receptor blockers (ARBs and cancer is controversial with meta-analyses of randomized controlled trials and observational studies reporting conflicting results. Thus, the objective of this study was to determine whether ARBs are associated with an overall increased risk of the four most common cancers, namely, lung, colorectal, breast and prostate cancers, and to explore these effects separately for each cancer type. We conducted a retrospective cohort study using a nested case-control analysis within the United Kingdom (UK General Practice Research Database. We assembled a cohort of patients prescribed antihypertensive agents between 1995, the year the first ARB (losartan entered the UK market, and 2008, with follow-up until December 31, 2010. Cases were patients newly-diagnosed with lung, colorectal, breast and prostate cancer during follow-up. We used conditional logistic regression to estimate adjusted rate ratios (RRs and 95% confidence intervals (CIs of cancer incidence, comparing ever use of ARBs with ever use of diuretics and/or beta-blockers. The cohort included 1,165,781 patients, during which 41,059 patients were diagnosed with one of the cancers under study (rate 554/100,000 person-years. When compared to diuretics and/or beta-blockers, ever use of ARBs was not associated with an increased rate of cancer overall (RR: 1.00; 95% CI: 0.96-1.03 or with each cancer site separately. The use of angiotensin-converting enzyme inhibitors and calcium channel blockers was associated with an increased rate of lung cancer (RR: 1.13; 95% CI: 1.06-1.20 and RR: 1.19; 95% CI: 1.12-1.27, respectively. This study provides additional evidence that the use of ARBs does not increase the risk of cancer overall or any of the four major cancer sites. Additional research is needed to further investigate a potentially increased risk of lung cancer with angiotensin-converting enzyme inhibitors and calcium channel blockers.

  4. Angiotensin-(1-7) attenuates disuse skeletal muscle atrophy in mice via its receptor, Mas.

    Science.gov (United States)

    Morales, María Gabriela; Abrigo, Johanna; Acuña, María José; Santos, Robson A; Bader, Michael; Brandan, Enrique; Simon, Felipe; Olguin, Hugo; Cabrera, Daniel; Cabello-Verrugio, Claudio

    2016-04-01

    Immobilization is a form of disuse characterized by a loss of strength and muscle mass. Among the main features are decreased IGF-1/Akt signalling and increased ubiquitin-proteasome pathway signalling, which induce greater myosin heavy chain degradation. Activation of the classical renin-angiotensin system (RAS) causes deleterious effects in skeletal muscle, including muscle wasting. In contrast, angiotensin-(1-7) [Ang-(1-7)], a peptide of the non-classical RAS, produces beneficial effects in skeletal muscle. However, the role of Ang-(1-7) in skeletal muscle disuse atrophy and independent of classical RAS activation has not been evaluated. Therefore, we assessed the functions of Ang-(1-7) and the Mas receptor in disuse muscle atrophyin vivousing unilateral cast immobilization of the hind limb in male, 12-week-old wild-type (WT) and Mas-knockout (Mas KO) mice for 1 and 14 days. Additionally, we evaluated the participation of IGF-1/IGFR-1/Akt signalling and ubiquitin-proteasome pathway expression on the effects of Ang-(1-7) immobilization-induced muscle atrophy. Our results found that Ang-(1-7) prevented decreased muscle strength and reduced myofiber diameter, myosin heavy chain levels, and the induction of atrogin-1 and MuRF-1 expressions, all of which normally occur during immobilization. Analyses indicated that Ang-(1-7) increases IGF-1/IGFR-1/Akt pathway signalling through IGFR-1 and Akt phosphorylation, and the concomitant activation of two downstream targets of Akt, p70S6K and FoxO3. These anti-atrophic effects of Ang-(1-7) were not observed in Mas KO mice, indicating crucial participation of the Mas receptor. This report is the first to propose anti-atrophic effects of Ang-(1-7) via the Mas receptor and the participation of the IGF-1/IGFR-1/Akt/p70S6K/FoxO3 mechanism in disuse skeletal muscle atrophy. © 2016. Published by The Company of Biologists Ltd.

  5. Angiotensin-(1-7 attenuates disuse skeletal muscle atrophy in mice via its receptor, Mas

    Directory of Open Access Journals (Sweden)

    María Gabriela Morales

    2016-04-01

    Full Text Available Immobilization is a form of disuse characterized by a loss of strength and muscle mass. Among the main features are decreased IGF-1/Akt signalling and increased ubiquitin-proteasome pathway signalling, which induce greater myosin heavy chain degradation. Activation of the classical renin-angiotensin system (RAS causes deleterious effects in skeletal muscle, including muscle wasting. In contrast, angiotensin-(1-7 [Ang-(1-7], a peptide of the non-classical RAS, produces beneficial effects in skeletal muscle. However, the role of Ang-(1-7 in skeletal muscle disuse atrophy and independent of classical RAS activation has not been evaluated. Therefore, we assessed the functions of Ang-(1-7 and the Mas receptor in disuse muscle atrophy in vivo using unilateral cast immobilization of the hind limb in male, 12-week-old wild-type (WT and Mas-knockout (Mas KO mice for 1 and 14 days. Additionally, we evaluated the participation of IGF-1/IGFR-1/Akt signalling and ubiquitin-proteasome pathway expression on the effects of Ang-(1-7 immobilization-induced muscle atrophy. Our results found that Ang-(1-7 prevented decreased muscle strength and reduced myofiber diameter, myosin heavy chain levels, and the induction of atrogin-1 and MuRF-1 expressions, all of which normally occur during immobilization. Analyses indicated that Ang-(1-7 increases IGF-1/IGFR-1/Akt pathway signalling through IGFR-1 and Akt phosphorylation, and the concomitant activation of two downstream targets of Akt, p70S6K and FoxO3. These anti-atrophic effects of Ang-(1-7 were not observed in Mas KO mice, indicating crucial participation of the Mas receptor. This report is the first to propose anti-atrophic effects of Ang-(1-7 via the Mas receptor and the participation of the IGF-1/IGFR-1/Akt/p70S6K/FoxO3 mechanism in disuse skeletal muscle atrophy.

  6. Inhibition of angiotensin Ⅱ and blockade of endothelin receptors reduce arterial calcification in rats

    Institute of Scientific and Technical Information of China (English)

    Juxiang LI; Shengying WU; Chunshui PAN; Yongfen QI; Bin GENG; Xiuhua LIU; Chaoshu TANG

    2004-01-01

    Objective To examine whether the two vascular paracrine/autocrine factors, angiotensin Ⅱ (Ang Ⅱ) and endothelin, participate in the pathogenesis of arterial calcification. Methods Nicotine and vitamin D3 treated rats were studied. Vascular calcification was confirmed by using Von Kossa staining, measurement of calcium content,45Ca2+ uptake assay and alkaline phosphatase (ALP) activity. The plasma and vascular Ang Ⅱ and endothelin levels were measured by using radioimmunoassay. Angiotensinogen and endothelin mRNA levels were determined by RTPCR. Results The arterial calcium content, 45Ca2+ uptake and ALP activity were increased in calcification groups compared with control ( P < 0.01 ). Administration of the angiotensin receptor antagonist losartan, the endothelin receptor antagonist bosentan, and the angiotensin-converting enzyme inhibitor captopril reduced significantly the arterial calcium content, 45Ca2+ uptake and ALP activity. In addition, the plasma and aortic Ang Ⅱ and endothelin contents, and vascular angiotensinogen and endothelin mRNA expression were significantly up-regulated ( P <0.05).Conclusions These findings suggest that functional renin-angiotensin system and endothelin pathway are involved in vascular calcification, and that activation of these systems could potentiate pathogenesis of arterial calcification. ( J Geriatr Cardiol 2004;1(2) :108-113. )

  7. Activation of intracellular angiotensin AT2 receptors induces rapid cell death in human uterine leiomyosarcoma cells

    DEFF Research Database (Denmark)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen

    2015-01-01

    The presence of AT2 receptors in mitochondria and their role in NO generation and cell aging were recently demonstrated in various human and mouse non-tumour cells. We investigated the intracellular distribution of AT2 receptors including their presence in mitochondria and the role in the induction...... densities in mitochondria. Activation of the cell membrane AT2 receptors by a concomitant treatment with angiotensin II and the AT1 receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT2 receptor...... of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT2 receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high...

  8. Individual long-term albuminuria exposure during angiotensin receptor blocker therapy is the optimal predictor for renal outcome

    NARCIS (Netherlands)

    Felix Kröpelin, Tobias; de Zeeuw, Dick; Holtkamp, Frank Arjan; Packham, David Kenneth; L Heerspink, Hiddo J

    2016-01-01

    BACKGROUND: Albuminuria reduction due to angiotensin receptor blockers (ARBs) predicts subsequent renoprotection. Relating the initial albuminuria reduction to subsequent renoprotection assumes that the initial ARB-induced albuminuria reduction remains stable during follow-up. The aim of this study

  9. Estimation of the number of angiotensin II AT1 receptors in rat kidney afferent and efferent arterioles

    DEFF Research Database (Denmark)

    Razga, Zsolt; Nyengaard, Jens Randel

    2007-01-01

    of angiotensin II AT1 receptors along the length of the arterioles and per arteriole, we combined immunoelectron microscopy with stereology. RESULTS: The number of AT1 receptor molecules was significantly lower in the renin-positive smooth muscle cells (SMCs) than in the renin-negative SMCs of the afferent......OBJECTIVE: To examine the effects of the renin-angiotensin system (RAS) on renal arterioles to determine the association between the distribution of angiotensin II AT1 receptors and the morphologic and physiologic heterogeneity of renal arterioles. STUDY DESIGN: To estimate the number...... and efferent arterioles. There were no significant differences along and between the afferent and efferent arterioles in relative number of AT1 receptors of endothelial cells or SMCs. CONCLUSION: Our results suggest that the heterogeneous activity of angiotensin II in SMCs and the different permeabilities...

  10. Angiotensin converting enzyme 2 and atherosclerosis.

    Science.gov (United States)

    Wang, Yutang; Tikellis, Chris; Thomas, Merlin C; Golledge, Jonathan

    2013-01-01

    Angiotensin converting enzyme 2 (ACE2) is a homolog of angiotensin converting enzyme (ACE) which generates angiotensin II from angiotensin I. ACE, its product angiotensin II and the downstream angiotensin type I receptor are important components of the renin-angiotensin system (RAS). Angiotensin II, the most important component of the RAS, promotes the development of atherosclerosis. The identification of ACE2 in 2000 opened a new chapter of research on the regulation of the RAS. ACE2 degrades pro-atherosclerotic angiotensin II and generates anti-atherosclerotic angiotensin 1-7. In this review, we explored the importance of ACE2 in protecting experimental animals from developing atherosclerosis and its involvement in human atherosclerosis. We also examined the published evidence assessing the importance of ACE2 in different cell types relevant to atherosclerosis and putative underlying cellular and molecular mechanisms linking ACE2 with protection from atherosclerosis. ACE2 shifts the balance from angiotensin II to angiotensin 1-7 inhibiting the progression of atherosclerosis in animal models.

  11. Cardiac mortality in users of olmesartan, other angiotensin-receptor blockers and angiotensin-converting enzyme inhibitors.

    Science.gov (United States)

    Walker, Alexander M; Liang, Caihua; Clifford, C Robin; Parker, Crawford; Feldman, Allen

    2014-04-01

    Clinical trials of olmesartan for prevention of progression of renal disease in patients with diabetes showed renal protection but an unexpected imbalance in cardiac deaths. The US Food and Drug Administration requested from the manufacturer a cohort study of olmesartan, other angiotensin-receptor blockers (ARBs), and angiotensin-converting enzyme (ACE) inhibitors in a large population. A retrospective cohort study was conducted with the cooperation of a US health insurer. Subject entry and follow-up ran from 2002 through 2009. In propensity-matched cohorts, the primary analysis considered continuous current users. Endpoints were sudden cardiac death (SCD) and all-cause mortality, identified through the US National Death Index, supplemented by insurance and hospital discharge data. Statistical estimation was based on proportional hazards analyses with 95% confidence intervals. Power calculations had shown that 25,000 olmesartan initiators would be required to detect relative risks (RRs) of SCD of twofold or greater. A total of 57,123 initiators of olmesartan were matched 1:2 to initiators of other ARBs and 41,801 to initiators of ACE inhibitors. Average follow-up time ranged from 8 to 9 months. Olmesartan initiators and comparators experienced similar patterns of both outcomes, with RRs ≤1.0 and upper confidence bounds ≤1.6. Among persons with prior use of hypoglycemic agents, in comparison with other ARBs, the RR of SCD for olmesartan users was 0.8, with an upper confidence bound of 2.2. The results of this well-powered study do not raise concerns for the risk of SCD or death from all causes among olmesartan users in comparison with users of other ARBs or ACE inhibitors. Copyright © 2013 John Wiley & Sons, Ltd.

  12. Urinary angiotensin-converting enzyme 2 in hypertensive patients may be increased by olmesartan, an angiotensin II receptor blocker.

    Science.gov (United States)

    Furuhashi, Masato; Moniwa, Norihito; Mita, Tomohiro; Fuseya, Takahiro; Ishimura, Shutaro; Ohno, Kohei; Shibata, Satoru; Tanaka, Marenao; Watanabe, Yuki; Akasaka, Hiroshi; Ohnishi, Hirofumi; Yoshida, Hideaki; Takizawa, Hideki; Saitoh, Shigeyuki; Ura, Nobuyuki; Shimamoto, Kazuaki; Miura, Tetsuji

    2015-01-01

    Angiotensin-converting enzyme 2 (ACE2) is highly expressed in the kidney and converts angiotensin (Ang) II to Ang-(1-7), a renoprotective peptide. Urinary ACE2 has been shown to be elevated in patients with chronic kidney disease. However, the effects of antihypertensive agents on urinary ACE2 remain unclear. Of participants in the Tanno-Sobetsu cohort study in 2011 (n = 617), subjects on no medication (n = 101) and hypertensive patients treated with antihypertensive agents, including the calcium channel blockers amlodipine and long-acting nifedipine; the ACE inhibitor enalapril; and the Ang II receptor blockers losartan, candesartan, valsartan, telmisartan, and olmesartan, for more than 1 year (n = 100) were enrolled, and urinary ACE2 level was measured. Glucose and hemoglobin A1c were significantly higher in patients treated with enalapril, telmisartan or olmesartan than in the control subjects. Urinary albumin-to-creatinine ratio (UACR) was significantly higher in patients treated with enalapril than in the control subjects. Urinary ACE2 level was higher in the olmesartan-treated group, but not the other treatment groups, than in the control group. Urinary ACE2 level was positively correlated with systolic blood pressure (r = 0.211; P = 0.003), UACR (r = 0.367; P olmesartan was an independent predictor of urinary ACE2 level. In contrast with other antihypertensive drugs, olmesartan may uniquely increase urinary ACE2 level, which could potentially offer additional renoprotective effects. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Dissociation between the circulating renin-angiotensin system and angiotensin II receptors in central losartan-induced hypertension

    Directory of Open Access Journals (Sweden)

    A.M. Sugawara

    2002-09-01

    Full Text Available Losartan, an AT1 angiotensin II (ANG II receptor non-peptide antagonist, induces an increase in mean arterial pressure (MAP when injected intracerebroventricularly (icv into rats. The present study investigated possible effector mechanisms of the increase in MAP induced by icv losartan in unanesthetized rats. Male Holtzman rats (280-300 g, N = 6/group with a cannula implanted into the anterior ventral third ventricle received an icv injection of losartan (90 µg/2 µl that induced a typical peak pressor response within 5 min. In one group of animals, this response to icv losartan was completely reduced from 18 ± 1 to 4 ± 2 mmHg by intravenous (iv injection of losartan (2.5-10 mg/kg, and in another group, it was partially reduced from 18 ± 3 to 11 ± 2 mmHg by iv prazosin (0.1-1.0 mg/kg, an alpha1-adrenergic antagonist (P<0.05. Captopril (10 mg/kg, a converting enzyme inhibitor, injected iv in a third group inhibited the pressor response to icv losartan from 24 ± 3 to 7 ± 2 mmHg (P<0.05. Propranolol (10 mg/kg, a ß-adrenoceptor antagonist, injected iv in a fourth group did not alter the pressor response to icv losartan. Plasma renin activity and serum angiotensin-converting enzyme activity were not altered by icv losartan in other animals. The results suggest that the pressor effect of icv losartan depends on angiotensinergic and alpha1-adrenoceptor activation, but not on increased circulating ANG II.

  14. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers decrease the incidence of atrial fibrillation: a meta-analysis.

    Science.gov (United States)

    Huang, Gang; Xu, Jun-bo; Liu, Jian-xiong; He, Yong; Nie, Xiao-li; Li, Qiu; Hu, Yong-mei; Zhao, Si-qin; Wang, Mian; Zhang, Wen-yong; Liu, Xiao-rong; Wu, Tao; Arkin, Akram; Zhang, Ting-jie

    2011-07-01

    There is not a general agreement regarding antiarrhythmic effects on atrial fibrillation (AF) of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). This study was to assess whether ACEIs and ARBs could decrease the incidence of AF. Medline, Embase and Cochrane Library databases were searched for trials reported from 1950 to May 2009. Search terms included 'randomized controlled trial (RCT), controlled clinical trials, random allocation' and medical subject headings that included all spellings of ACEIs and ARBs agents, 'atrial fibrillation' and 'atrial flutter'. Randomized, controlled human trials of ACEIs or ARBs reporting AF were included. Data were extracted independently by two reviewers using a predefined data extraction sheet, including study quality indicators. Meta-analysis and subgroup analyses were carried out with a random effects model. Twenty-one trials including 91,381 patients and 5730 AF events were identified. Overall, ACEIs/ARBs reduced the relative risk (c) of AF by 25%. In primary and secondary prevention, ACEIs/ARBs decreased the incidence of AF by 24% and 27%, respectively. Patients with hypertension (RR: 0·71, 95%CI: 0·54-0·92), patients with chronic heart failure (RR: 0·58, 95%CI: 0·39-0·87) and those with AF (RR: 0·71, 95%CI: 0·52-0·96) benefited from ACEIs/ARBs treatment. ACEIs/ARBs are effective for primary prevention and secondary prevention of AF. They decrease the incidence of AF especially in patients with hypertension, patients with chronic heart failure and those with AF. © 2011 The Authors. European Journal of Clinical Investigation © 2011 Stichting European Society for Clinical Investigation Journal Foundation.

  15. Impact of Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers on Mortality of Coronary Artery Bypass Grafting

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    Ahmad Sharafi

    2015-10-01

    Full Text Available Background: There is controversy over the potential benefits/harms of the usage of angiotensin-converting enzyme inhibitors (ACEIs or angiotensin receptor blockers (ARBs as regards the postoperative mortality of coronary artery bypass grafting (CABG. This study investigates the correlation between the in-hospital mortality of CABG and the preoperative administration of ACEI/ARB.Methods: Out of 10055 consecutive patients with isolated CABG from 2006 to 2009, 4664 (46.38% patients received preoperative ACEI/ARB. Data were gathered from the Cardiac Surgery Registry of Tehran Heart Center. In-hospital mortality was defined as death within the same admission for surgery. Adjusted for confounders, multivariable logistic regression models were used to evaluate the impact of preoperative ACEI/ARB therapy on in-hospital death.Results: The mean age of the patients was 60.04 ± 9.51 years and 7364 (73.23% were male. Eighty-seven (0.86% patients expired within 30 days. Multivariate analysis revealed that the administration of ACEI/ARB significantly protected against in-hospital deaths inasmuch as there were 33 (0.70% vs. 54 (1.0% deaths in the ACEI/ARB positive and negative groups, respectively (OR: 0.628; p value = 0.09. Patients without ACEI/ARB were more likely to have a higher global ejection fraction.Conclusion: Preoperative ACEI usage in patients undergoing CABG can be associated with decreased in-hospital mortality. Large-scale randomized clinical trials are suggested.

  16. Angiotensin-converting enzyme inhibitors/angiotensin receptor blockers therapy and colorectal cancer: a systematic review and meta-analysis.

    Science.gov (United States)

    Dai, Yi-Ning; Wang, Jing-Hua; Zhu, Jin-Zhou; Lin, Jie-Qiong; Yu, Chao-Hui; Li, You-Ming

    2015-09-01

    We aim to investigate the association between angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin receptor blockers (ARBs) therapy and colorectal cancer (CRC) by conducting a systematic review with meta-analysis. Literature was searched on PubMed, Scopus, and the Cochrane library to identify relevant studies evaluating ACEIs/ARBs therapy and risk of CRC incidence or survival of CRC patients. Pooled risk ratio (RR) with 95% confidence intervals was calculated for the association between ACEIs/ARBs and CRC risk and mortality. Eleven observational studies were included in the systematic review. A meta-analysis of six studies totaling 113,048 individuals indicated a 6% decreased risk of CRC in ACEIs/ARBs users compared to non-users (95% CI 0.89-0.98). In the four case-control studies, individuals using ACEIs/ARBs were associated with a 6% decreased risk of CRC (95% CI 0.90-0.99). The meta-analysis of three studies investigating the relationship between ACEIs/ARBs and survival of CRC did not show a significantly decreased mortality in ACEIs/ARBs users (RR 0.81, 95% CI 0.60-1.09). Seven studies evaluated the dose-response relationship between ACEIs/ARBs therapy and CRC, and two of them showed that the association was related to longer duration and higher dose. CEIs/ARBs therapy might be associated with a reduce risk of CRC development, but whether use of these medications improves the outcomes of CRC remains unknown. Large-scale and more robust studies are needed to further explore this association.

  17. Increased Tumor Response to Neoadjuvant Therapy Among Rectal Cancer Patients Taking Angiotensin-Converting Enzyme Inhibitors or Angiotensin Receptor Blockers

    Science.gov (United States)

    Morris, Zachary S.; Saha, Sandeep; Magnuson, William J.; Morris, Brett A.; Borkenhagen, Jenna F.; Ching, Alisa; Hirose, Gayle; McMurry, Vanesa; Francis, David M.; Harari, Paul M.; Chappell, Rick; Tsuji, Stuart; Ritter, Mark A.

    2016-01-01

    BACKGROUND Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are commonly used antihypertensive medications that have been reported to affect aberrant angiogenesis and the dysregulated inflammatory response. Because of such mechanisms, it was hypothesized that these medications might affect the tumor response to neoadjuvant radiation in patients with rectal cancer. METHODS One hundred fifteen patients who were treated with neoadjuvant radiation at the University of Wisconsin (UW) between 1999 and 2012 were identified. Univariate analyses were performed with anonymized patient data. In a second independent data set, 186 patients with rectal cancer who were treated with neoadjuvant radiation at the Queen’s Medical Center of the University of Hawaii (UH) between 1995 and 2010 were identified. These data were independently analyzed as before. Multivariate analyses were performed with aggregate data. RESULTS Among patients taking ACEIs/ARBs in the UW data set, a significant 3-fold increase in the rate of pathologic complete response (pCR) to neoadjuvant therapy (52% vs 17%, P = .001) was observed. This finding was confirmed in the UH data set, in which a significant 2-fold–increased pCR rate (24% vs 12%, P = .03) was observed. Identified patient and treatment characteristics were otherwise balanced between patients taking and not taking ACEIs/ARBs. No significant effect was observed on pCR rates with other medications, including statins, metformin, and aspirin. Multivariate analyses of aggregate data identified ACEI/ARB use as a strong predictor of pCR (odds ratio, 4.02; 95% confidence interval, 2.06–7.82; P ACEIs/ARBs among patients with rectal cancer is associated with a significantly increased rate of pCR after neoadjuvant treatment. PMID:27203227

  18. Vascular response to angiotensin II predicts long-term prognosis in patients undergoing coronary artery bypass grafting

    NARCIS (Netherlands)

    Harst, van der Pim; Volbeda, M.; Voors, Adriaan; Buikema, Hendrik; Wassmann, S.; Bohm, M.; Nickenig, G.; van Gilst, W.H.

    2004-01-01

    Persistent activation of the renin-angiotensin system leads to downregulation of the angiotensin type-1 receptor, and consequently, to a decreased response to exogenous angiotensin II. In the present study, we investigated the association of angiotensin II responsiveness to clinical outcome after co

  19. Exercício de força ativa a via AKT/mTor pelo receptor de angiotensina II tipo I no músculo cardíaco de ratos Activation of AKT-mTor signaling pathways by angiotensin II receptor type 1 after a session of strength exercise in cardiac muscle of rats

    Directory of Open Access Journals (Sweden)

    Stéphano Freitas Soares Melo

    2011-09-01

    Full Text Available O receptor de angiotensina II tipo I (AT1 tem uma importante participação no desenvolvimento da hipertrofia cardíaca. Em um trabalho publicado anteriormente, por nosso grupo, demonstramos que o bloqueio do receptor AT1 durante o treinamento de força inibiu a hipertrofia cardíaca em ratos. Por isso, o objetivo deste trabalho foi estudar a participação do receptor AT1 na ativação de vias de sinalização intracelular relacionadas com o aumento da síntese de proteína em ratos submetidos a uma sessão de exercício de força. Para isso, realizamos um experimento com seis grupos de animais (n = 6; cada: controle (Con, exercitado e sacrificado cinco minutos após o exercício (Exe 5, exercitado e sacrificado 30 minutos após o exercício (Exe 30, controle tratado com losartan (Con Los, tratado com losartan, exercitado e sacrificado cinco minutos após o exercício (Exe 5 Los, tratado com losartan, exercitado e sacrificado 30 minutos após o exercício (Exe 30 Los. Os resultados mostram que no grupo Exe 5 e Exe 30 ocorreu um aumento de 63% (P The angiotensin II type I (AT1 receptor has an important participation in the development of cardiac hypertrophy. Previously, we have shown that AT1 receptor participates in the cardiac hypertrophy induced by resistance training in rats. Here, we studied the involvement of AT1 receptor in the activation of intracellular signaling pathways related to the concentric HC in rats submitted to a session of strength exercise. Male Wistar rats were divided into 6 groups (n= 6 each: control (Con; exercised and killed 5 minutes after exercise (Exe 5; exercised and killed 30 minutes after exercise (Exe 30; control treated with Losartan (Con Los; treated with Losartan, exercised and killed 5 minutes after the exercise (Exe Los 5; treated with Losartan, exercised and killed 30 minutes after training (Exe Los 30. The results show that phosphorylation activity of AKT in group Exe 5 and Exe 30 increased 63% (P < 0

  20. Examining the association of olmesartan and other angiotensin receptor blockers with overall and cause-specific mortality.

    Science.gov (United States)

    Lin, Jou-Wei; Chang, Chia-Hsuin; Caffrey, James L; Wu, Li-Chiu; Lai, Mei-Shu

    2014-05-01

    Concerns about an increased cardiovascular risk with the angiotensin receptor blocker, olmesartan, prompted the current study to examine associations between olmesartan and other angiotensin receptor blockers with overall and cause-specific mortalities. We collected patients who started to use losartan, valsartan, irbesartan, candesartan, telmisartan, and olmesartan between January 1, 2004, and December 31, 2009, from Taiwan's National Health Insurance claims database. Prescribed drug types, dosage, and other clinical information were collected. Overall mortality and cause-specific mortality were ascertained through linkages with Taiwan's National Death Registry. Two follow-up analyses, labeled intention-to-treat and as-treated, were conducted. A Cox proportional hazard regression model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) using losartan as the reference group. A total of 690 463 subjects were included, with a mean follow-up ranging from a low of 2.8 years for olmesartan to a high of 4.1 years for irbesartan. Subjects who began with valsartan had a modest but significantly increased risk of overall mortality (HR, 1.04; 95% CI, 1.02-1.06) compared with losartan. Irbesartan (HR, 0.96; 95% CI, 0.94-0.99), candesartan (HR, 0.95; 95% CI, 0.92-0.99), telmisartan (HR, 0.93; 95% CI, 0.90-0.96), and olmesartan (HR, 0.93; 95% CI, 0.88-0.97) were associated with a slightly lower overall mortality risk than losartan. The analysis indicates that the differences in mortality risk among individual angiotensin receptor blockers were only marginal and thus less likely to be clinically important. Although uncontrolled confounding might still exist, olmesartan does not seem to increase cardiovascular risk compared with losartan.

  1. Hypoxia-Induced Collagen Synthesis of Human Lung Fibroblasts by Activating the Angiotensin System

    OpenAIRE

    Shan-Shan Liu; Hao-Yan Wang; Jun-Ming Tang; Xiu-Mei Zhou

    2013-01-01

    The exact molecular mechanism that mediates hypoxia-induced pulmonary fibrosis needs to be further clarified. The aim of this study was to explore the effect and underlying mechanism of angiotensin II (Ang II) on collagen synthesis in hypoxic human lung fibroblast (HLF) cells. The HLF-1 cell line was used for in vitro studies. Angiotensinogen (AGT), angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1R) and angiotensin II type 2 receptor (AT2R) expression levels in human ...

  2. Plasma Angiotensin II Levels In Women With Type 2 Diabetes With Or Without Hypertension

    OpenAIRE

    Ariadno, Etra

    2013-01-01

    ABSTRACT Background. Hypertension is a major risk for the development and progressivity complication of macro and microvascular of diabetes mellitus. Renin-angiotensin-aldosteron system (RAAS), insulin resistance, endothelial dysfunction and autonomic nervous dysfunction play an important part in the pathogenesis of hypertension and type 2 diabetes mellitus. In RAAS, increased angiotensin II constricts arterioles, raises total peripheral resistance and blood volume. The rise in intravascular ...

  3. Is there any difference between angiotensin converting enzyme inhibitors and angiotensin receptor blockers for heart failure?

    Directory of Open Access Journals (Sweden)

    Carmen Rain

    2015-07-01

    Full Text Available Los antagonistas del receptor de angiotensina son habitualmente considerados equivalentes a los inhibidores de la enzima convertidora de angiotensina en pacientes con insuficiencia cardiaca crónica y fracción de eyección disminuida. Incluso algunas de las principales guías clínicas lo recomiendan como primera alternativa debido a un perfil de efectos adversos más favorable. Utilizando la base de datos Epistemonikos, la cual es mantenida mediante búsquedas en 30 bases de datos, identificamos cuatro revisiones sistemáticas que en conjunto incluyen ocho estudios aleatorizados. Realizamos un metanálisis y tablas de resumen de los resultados utilizando el método GRADE. Concluimos que los antagonistas del receptor de angiotensina probablemente tienen el mismo efecto sobre la mortalidad que los inhibidores de la enzima convertidora, y podrían ser equivalentes también en su efecto sobre el riesgo de hospitalizaciones. El abandono de tratamiento por efectos adversos es probablemente menor con antagonistas del receptor de angiotensina que con inhibidores de la enzima convertidora.

  4. Endothelin ETA receptors and endothelium partially mediate the positive inotropic and lusitropic effects of angiotensin II.

    Science.gov (United States)

    Castro-Chaves, Paulo; Roncon-Albuquerque, Roberto; Leite-Moreira, Adelino F

    2006-08-21

    We analyzed the influence of endothelin-1 and endocardial endothelium on the myocardial effects of angiotensin-II. Angiotensin-II (10(-9)-10(-5) M) was tested in rabbit right papillary muscles in absence (Protocol-A) or presence of PD-145065 (10(-7) M; Protocol-B), BQ-123 (10(-7) M; Protocol-C) or losartan (10(-6) M; Protocol-E), as well as, after removing the endocardial endothelium with Triton X-100 0.5% (Protocol-D). In Protocol-F increasing concentrations of endothelin-1 (10(-10)-10(-8) M) were added in presence of angiotensin-II (10(-7) M) after selective removal of the endocardial endothelium. In Protocol-A, angiotensin-II had dose-dependent positive inotropic and lusitropic effects, maximal at 10(-6) M increasing 122+/-13% active tension, 117+/-16% dT/dtmax and 86+/-9% dT/dtmin. In Protocols B, C and D the inotropic and lusitropic effects of angiotensin-II were significantly attenuated. The same concentration (10(-6) M) of angiotensin-II increased respectively 48+/-11%, 59+/-27% and 72+/-16% active tension; 54+/-14%, 54+/-20% and 32+/-9% dT/dtmax; and 39+/-8%, 48+/-19% and 59+/-11% dT/dtmin; and 40+/-10%. EC(50) for active tension significantly increased from -7.8+/-0.1 logM in Protocol A to -7.1+/-0.3, -6.7+/-0.4 and -6.8+/-0.3 logM in Protocols B, C and D respectively, while Emax decreased from 106+/-14% in Protocol A to 50+/-14 and 51+/-19% in Protocols B and C respectively, but did not significantly change in Protocol D (114+/-25%). Losartan completely blocked the inotropic and lusitropic effects of angiotensin-II, while the attenuation of these effects after the selective removal of the endocardial endothelium was blunted by concomitant administration of endothelin-1 (Protocol F). In conclusion, angiotensin-II has a dose-dependent positive inotropic effect that depends, to a great extent, on endothelin ETA receptor activation and intact endocardial endothelium.

  5. Bone marrow angiotensin AT1 receptor regulates differentiation of monocyte lineage progenitors from hematopoietic stem cells.

    Science.gov (United States)

    Tsubakimoto, Yoshinori; Yamada, Hiroyuki; Yokoi, Hirokazu; Kishida, Sou; Takata, Hiroki; Kawahito, Hiroyuki; Matsui, Akihiro; Urao, Norifumi; Nozawa, Yoshihisa; Hirai, Hideyo; Imanishi, Jiro; Ashihara, Eishi; Maekawa, Taira; Takahashi, Tomosaburo; Okigaki, Mitsuhiko; Matsubara, Hiroaki

    2009-10-01

    The angiotensin II (Ang II) type 1 (AT(1)) receptor is expressed in bone marrow (BM) cells, whereas it remains poorly defined how Ang II regulates differentiation/proliferation of monocyte-lineage cells to exert proatherogenic actions. We generated BM chimeric apoE(-/-) mice repopulated with AT(1)-deficient (Agtr1(-/-)) or wild-type (Agtr1(+/+)) BM cells. The atherosclerotic development was significantly reduced in apoE(-/-)/BM-Agtr1(-/-) mice compared with apoE(-/-)/BM-Agtr1(+/+) mice, accompanied by decreased numbers of BM granulocyte/macrophage progenitors (GMP:c-Kit(+)Sca-1(-)Lin(-)CD34(+)CD16/32(+)) and peripheral blood monocytes. Macrophage-colony-stimulating factor (M-CSF)-induced differentiation from hematopoietic stem cells (HSCs:c-Kit(+)Sca-1(+)Lin(-)) to promonocytes (CD11b(high)Ly-6G(low)) was markedly reduced in HSCs from Agtr1(-/-) mice. The expression of M-CSF receptor c-Fms was decreased in HSCs/promonocytes from Agtr1(-/-) mice, accompanied by a marked inhibition in M-CSF-induced phosphorylation of PKC-delta and JAK2. c-Fms expression in HSCs/promonocytes was mainly regulated by TNF-alpha derived from BM CD45(-)CD34(-) stromal cells, and Ang II specifically regulated the TNF-alpha synthesis and release from BM stromal cells. Ang II regulates the expression of c-Fms in HSCs and monocyte-lineage cells through BM stromal cell-derived TNF-alpha to promote M-CSF-induced differentiation/proliferation of monocyte-lineage cells and contributes to the proatherogenic action.

  6. Transient Receptor Potential Melastatin 7 Cation Channel Kinase: New Player in Angiotensin II-Induced Hypertension.

    Science.gov (United States)

    Antunes, Tayze T; Callera, Glaucia E; He, Ying; Yogi, Alvaro; Ryazanov, Alexey G; Ryazanova, Lillia V; Zhai, Alexander; Stewart, Duncan J; Shrier, Alvin; Touyz, Rhian M

    2016-04-01

    Transient receptor potential melastatin 7 (TRPM7) is a bifunctional protein comprising a magnesium (Mg(2+))/cation channel and a kinase domain. We previously demonstrated that vasoactive agents regulate vascular TRPM7. Whether TRPM7 plays a role in the pathophysiology of hypertension and associated cardiovascular dysfunction is unknown. We studied TRPM7 kinase-deficient mice (TRPM7Δkinase; heterozygous for TRPM7 kinase) and wild-type (WT) mice infused with angiotensin II (Ang II; 400 ng/kg per minute, 4 weeks). TRPM7 kinase expression was lower in heart and aorta from TRPM7Δkinase versus WT mice, effects that were further reduced by Ang II infusion. Plasma Mg(2+) was lower in TRPM7Δkinase versus WT mice in basal and stimulated conditions. Ang II increased blood pressure in both strains with exaggerated responses in TRPM7Δkinase versus WT groups (Phypertension is exaggerated, cardiac remodeling and left ventricular dysfunction are amplified, and endothelial function is impaired. These processes are associated with hypomagnesemia, blunted TRPM7 kinase expression/signaling, endothelial nitric oxide synthase downregulation, and proinflammatory vascular responses. Our findings identify TRPM7 kinase as a novel player in Ang II-induced hypertension and associated vascular and target organ damage. © 2016 American Heart Association, Inc.

  7. Impact of drug price adjustments on utilization of and expenditures on angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in Taiwan.

    Science.gov (United States)

    Huang, Shiou-Huei; Hsu, Chien-Ning; Yu, Shu-Hui; Cham, Thau-Ming

    2012-05-31

    A previous study has suggested that drug price adjustments allow physicians in Taiwan to gain greater profit by prescribing generic drugs. To better understand the effect of price adjustments on physician choice, this study used renin-angiotensin drugs (including angiotensin-converting enzyme inhibitors [ACEIs] and angiotensin receptor blockers [ARBs]) to examine the impact of price adjustments on utilization of and expenditures on patented and off-patent drugs with the same therapeutic indication. Using the Taiwan's Longitudinal Health Insurance Database (2005), we identified 147,157 patients received ACEIs and/or ARBs between 1997 and 2008. The annual incident and prevalent users of ACEIs, ARBs and overall renin-angiotensin drugs were examined. Box-Tiao intervention analysis was applied to assess the impact of price adjustments on monthly utilization of and expenditures on these drugs. ACEIs were divided into patented and off-patent drugs, off-patent ACEIs were further divided into original brands and generics, and subgroup analyses were performed. The number of incident renin-angiotensin drug users decreased over the study period. The number of prevalent ARB users increased and exceeded the cumulative number of first-time renin-angiotensin drug users starting on ARBs, implying that some patients switched from ACEIs to ARBs. After price adjustments, long term trend increases in utilization were observed for patented ACEIs and ARBs; a long-term trend decrease was observed for off-patent ACEIs; long-term trend change was not significant for overall renin-angiotensin drugs. Significant long-term trend increases in expenditures were observed for patented ACEIs after price adjustment in 2007 (200.9%, p = 0.0088) and in ARBs after price adjustments in 2001 (173.4%, p ACEIs after 2004 price adjustment (-156.9%, p ACEIs to ARBs within individuals is evident. Policy makers should reconsider the appropriateness of the current adjustment strategies applied to

  8. Effect of angiotensin II receptor blocker on experimental periodontitis in a mouse model of Marfan syndrome.

    Science.gov (United States)

    Suda, Naoto; Moriyama, Keiji; Ganburged, Ganjargal

    2013-01-01

    Marfan syndrome is an autosomal dominant disease characterized by aneurysm and dilatation of the aortic root, tall stature, and ectopia lentis. These manifestations reflect excessive signaling of transforming growth factor beta (TGF-β). Moreover, cases are frequently associated with severe periodontitis, which is a chronic inflammation of the gingiva, periodontal ligament, and alveolar bone. Recently, angiotensin II receptor blockers (ARBs) were discovered to be an effective drug class that can prevent aortic aneurysm and dilation in Marfan syndrome by inhibiting TGF-β signaling. To investigate the effect of ARB on the progression of periodontitis, the application of a potent ARB, telmisartan, was examined in a mouse model of Marfan syndrome (MgΔ). Six-week-old male heterozygous MgΔ and wild-type mice were challenged with Porphyromonas gingivalis, which causes chronic periodontitis, with and without telmisartan application. After infection, alveolar bone resorption was measured by micro-computed tomography (μCT), and inflammatory cytokine levels were examined. Infection of Porphyromonas gingivalis induced alveolar bone resorption in both MgΔ and wild-type mice. The amount of resorption was significantly larger in the former than the latter. Immunoarray and enzyme-linked immunosorbent assay (ELISA) analyses demonstrated that interleukin-17 (IL-17) and tumor necrosis factor alpha (TNF-α) levels were significantly higher in infected MgΔ mice than infected wild-type mice. Telmisartan treatment significantly suppressed the alveolar bone resorption of infected MgΔ mice. Telmisartan also significantly decreased levels of TGF-β, IL-17, and TNF-α in infected MgΔ mice to levels seen in infected wild-type mice. This study suggests that ARB can prevent the severe periodontitis frequently seen in Marfan syndrome.

  9. 2010 position paper of the Italian Society of Hypertension (SIIA): angiotensin receptor blockers and risk of cancer.

    Science.gov (United States)

    Volpe, Massimo; Morganti, Alberto

    2011-03-01

    Antihypertensive therapy has been demonstrated to significantly reduce cardiovascular and non-cardiovascular mortality in randomized controlled clinical trials. In the past, however, doubts have been raised on the safety of one class of blood pressure lowering drugs, namely the angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]), in terms of increased risk of myocardial infarction. Several comprehensive meta-analyses have definitely demonstrated no significant increased risk of myocardial infarction in patients treated with ARBs compared with placebo or any other active treatments. More recently, a partial meta-analysis has suggested a potential link between the use of this drug class and an increased risk of cancer. Although a further comprehensive network meta-analysis demonstrated the lack of any increased risk of cancer development or cancer mortality in patients treated with different antihypertensive drug classes, including ARBs, compared with placebo, this report has generated claims and uncertainties in the medical community and produced a vast echo in the lay press. The biological plausibility, the potential pathophysiological mechanisms, and the clinical evidence that rule out such hypotheses are discussed here. The present article, which represents a position paper of the Italian Society of Hypertension (SIIA), states that the benefits derived from the use of ARBs outweigh the potential risks, and that the use of these drugs should be maintained according to present indications.

  10. Affinity chromatography purification of angiotensin II receptor using photoactivable biotinylated probes.

    Science.gov (United States)

    Marie, J; Seyer, R; Lombard, C; Desarnaud, F; Aumelas, A; Jard, S; Bonnafous, J C

    1990-09-25

    We have developed biotinylated photoactivable probes that are suitable for covalent labeling of angiotensin II (AII) receptors and the subsequent purification of covalent complexes through immobilized avidin or streptavidin. One of these probes, biotin-NH(CH2)2SS(CH2)2CO-[Ala1,Phe(4N3)8]AII, which contains a cleavable disulfide bridge in its spacer arm and which displays, in its radioiodinated form, very high affinity for AII receptors (Kd approximately 1 nM), proved to be suitable for indirect affinity chromatography of rat liver receptor with facilitated recovery from avidin gels by use of reducing agents. This constituted the central step of an efficient partial purification scheme involving hydroxylapatite chromatography, streptavidin chromatography, and thiopropyl-Sepharose chromatography. SDS-PAGE analysis and autoradiography established the identity of the purified entity (molecular weight 65K) as the AII receptor. Possible ways of completing purification to homogeneity and extrapolation of the protocols to a preparative scale are discussed, as well as the potential contribution of our new probes to the study of the structural properties of angiotensin receptors.

  11. Beneficial effects of the activation of the angiotensin-(1-7) MAS receptor in a murine model of adriamycin-induced nephropathy.

    Science.gov (United States)

    Silveira, Kátia Daniela; Barroso, Lívia Corrêa; Vieira, Angélica Thomáz; Cisalpino, Daniel; Lima, Cristiano Xavier; Bader, Michael; Arantes, Rosa Maria Esteves; Dos Santos, Robson Augusto Souza; Simões-E-Silva, Ana Cristina; Teixeira, Mauro Martins

    2013-01-01

    Angiotensin-(1-7) [Ang-(1-7)] is a biologically active heptapeptide that may counterbalance the physiological actions of angiotensin II (Ang II) within the renin-angiotensin system (RAS). Here, we evaluated whether activation of the Mas receptor with the oral agonist, AVE 0991, would have renoprotective effects in a model of adriamycin (ADR)-induced nephropathy. We also evaluated whether the Mas receptor contributed for the protective effects of treatment with AT1 receptor blockers. ADR (10 mg/kg) induced significant renal injury and dysfunction that was maximal at day 14 after injection. Treatment with the Mas receptor agonist AVE 0991 improved renal function parameters, reduced urinary protein loss and attenuated histological changes. Renoprotection was associated with reduction in urinary levels of TGF-β. Similar renoprotection was observed after treatment with the AT1 receptor antagonist, Losartan. AT1 and Mas receptor mRNA levels dropped after ADR administration and treatment with losartan reestablished the expression of Mas receptor and increased the expression of ACE2. ADR-induced nephropathy was similar in wild type (Mas(+/+) ) and Mas knockout (Mas (-/-)) mice, suggesting there was no endogenous role for Mas receptor activation. However, treatment with Losartan was able to reduce renal injury only in Mas(+/+) , but not in Mas (-/-) mice. Therefore, these findings suggest that exogenous activation of the Mas receptor protects from ADR-induced nephropathy and contributes to the beneficial effects of AT1 receptor blockade. Medications which target specifically the ACE2/Ang-(1-7)/Mas axis may offer new therapeutic opportunities to treat human nephropathies.

  12. Interstitial Fibroblast-Like Cells Express Renin-Angiotensin System Components in a Fibrosing Murine Kidney

    OpenAIRE

    Okada, Hirokazu; Inoue, Tsutomu; Kanno, Yoshihiko; Kobayashi, Tatsuya; Watanabe, Yusuke; Kopp, Jeffrey B; Carey, Robert M.; SUZUKI, HIROMICHI

    2002-01-01

    Recently, the renin-angiotensin system (RAS) was implicated in organ fibrosis. However, few studies have examined the localization of RAS components, such as angiotensin II receptors, renin (REN), angiotensinogen (AGTN), and angiotensin-converting enzyme (ACE), in the fibrosing kidney. To localize these components in the fibrosing kidney, we used a murine model of renal fibrosis that shows an enhanced expression of angiotensin II type 1A receptor (AT1AR) and AGTN. Our results indicate that th...

  13. Does protein binding modulate the effect of angiotensin II receptor antagonists?

    Directory of Open Access Journals (Sweden)

    Marc P Maillard

    2001-03-01

    Full Text Available IntroductionAngiotensin II AT 1-receptor antagonists are highly bound to plasma proteins (≥ 99%. With some antagonists, such as DuP-532, the protein binding was such that no efficacy of the drug could be demonstrated clinically. Whether protein binding interferes with the efficacy of other antagonists is not known. We have therefore investigated in vitro how plasma proteins may affect the antagonistic effect of different AT1-receptor antagonists.MethodsA radio-receptor binding assay was used to analyse the interaction between proteins and the ability of various angiotensin II (Ang II antagonists to block AT1-receptors. In addition, the Biacore technology, a new technique which enables the real-time monitoring of binding events between two molecules, was used to evaluate the dissociation rate constants of five AT1-receptor antagonists from human serum albumin.ResultsThe in vitro AT 1-antagonistic effects of different Ang II receptor antagonists were differentially affected by the presence of human plasma, with rightward shifts of the IC50 ranging from one to several orders of magnitude. The importance of the shift correlates with the dissociation rate constants of these drugs from albumin. Our experiments also show that the way that AT1-receptor antagonists bind to proteins differs from one compound to another. These results suggest that the interaction with plasma proteins appears to modulate the efficacy of some Ang II antagonists.ConclusionAlthough the high binding level of Ang II receptor antagonist to plasma proteins appears to be a feature common to this class of compounds, the kinetics and characteristics of this binding is of great importance. With some antagonists, protein binding interferes markedly with their efficacy to block AT1-receptors.

  14. A combined role of calcium channel blockers and angiotensin receptor blockers in stroke prevention

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    Ji-Guang Wang

    2009-07-01

    Full Text Available Ji-Guang WangCentre for Epidemiological Studies and Clinical Trials, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, ChinaAbstract: Stroke is a leading cause of death and disability worldwide. The importance of lowering blood pressure for reducing the risk of stroke is well established. However, not all the benefits of antihypertensive treatments in stroke can be accounted for by reductions in BP and there may be differences between antihypertensive classes as to which provides optimal protection. Dihydropyridine calcium channel blockers, such as amlodipine, and angiotensin receptor blockers, such as valsartan, represent the two antihypertensive drug classes with the strongest supportive data for the prevention of stroke. Therefore, when combination therapy is required, a combination of these two antihypertensive classes represents a logical approach.Keywords: stroke, angiotensin, calcium channel, cerebrovascular, hypertension, blood pressure

  15. Combined Angiotensin Receptor Modulation in the Management of Cardio-Metabolic Disorders

    DEFF Research Database (Denmark)

    Paulis, Ludovit; Foulquier, Sébastien; Namsolleck, Pawel

    2016-01-01

    Cardiovascular and metabolic disorders, such as hypertension, insulin resistance, dyslipidemia or obesity are linked with chronic low-grade inflammation and dysregulation of the renin-angiotensin system (RAS). Consequently, RAS inhibition by ACE inhibitors or angiotensin AT1 receptor (AT1R......) blockers is the evidence-based standard for cardiovascular risk reduction in high-risk patients, including diabetics with albuminuria. In addition, RAS inhibition reduces the new onset of diabetes mellitus. Yet, the high and increasing prevalence of metabolic disorders, and the high residual risk even....... Therefore, a concept of dual AT1R/AT2R modulation emerges as a putative means for risk reduction in cardio-metabolic diseases. The approach employing simultaneous RAS blockade (AT1R) and RAS stimulation (AT2R) is distinct from previous attempts of double intervention in the RAS by dual blockade. Dual...

  16. The Prorenin and (Prorenin Receptor: New Players in the Brain Renin-Angiotensin System?

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    Wencheng Li

    2012-01-01

    Full Text Available It is well known that the brain renin-angiotensin (RAS system plays an essential role in the development of hypertension, mainly through the modulation of autonomic activities and vasopressin release. However, how the brain synthesizes angiotensin (Ang II has been a debate for decades, largely due to the low renin activity. This paper first describes the expression of the vasoconstrictive arm of RAS components in the brain as well as their physiological and pathophysiological significance. It then focus on the (prorenin receptor (PRR, a newly discovered component of the RAS which has a high level in the brain. We review the role of prorenin and PRR in peripheral organs and emphasize the involvement of brain PRR in the pathogenesis of hypertension. Some future perspectives in PRR research are heighted with respect to novel therapeutic target for the treatment of hypertension and other cardiovascular diseases.

  17. Angiotensin II receptor blocker-induced angioedema in the oral floor and epiglottis.

    Science.gov (United States)

    Shino, Masato; Takahashi, Katsumasa; Murata, Takaaki; Iida, Hideki; Yasuoka, Yoshihito; Furuya, Nobuhiko

    2011-01-01

    We report the rare case of angioedema (also known as Quincke edema), which was induced by valsartan, an angiotensin II receptor blocker (ARB). ARBs are a new class of antihypertensive agent that is developed to exclude the adverse effects of angiotensin-converting enzyme inhibitors. In theory, ARBs do not contribute to the occurrence of angioedema because they do not increase the serum level of bradykinin, the responsible substance for angioedema. However, some reports of ARB-induced angioedema have recently been published. In this study, we present the forth case and the first Asian case of angioedema due to valsartan, which is one of the ARBs. Otolaryngologist should be wary of the prescribing ARB and discontinue ARBs treatment soon, if angioedema is recognized.

  18. Expression and localization of the AT1 and AT2 angiotensin II receptors and α1A and α1D adrenergic receptors in aorta of hypertensive and diabetic rats.

    Science.gov (United States)

    Rodríguez, Jessica Edith; Romero-Nava, Rodrigo; Reséndiz-Albor, Aldo Arturo; Rosales-Cruz, Erika; Hong, Enrique; Huang, Fengyang; Villafaña, Santiago

    2017-01-01

    Hypertension and diabetes are multifactorial diseases that frequently coexist and exacerbate each another. During the development of diabetes, the impairment of noradrenergic and renin-angiotensin systems has been reported in the response mediated by α1-AR and AT1 receptors. Although their participation in the development of cardiovascular complications is still controversial, some studies have found increased or diminished response to the vasoconstrictive effect of noradrenaline or angiotensin II in a time-dependent manner of diabetes. Thus, the aim of this work was to investigate the possible changes in the expression or localization of α1-AR (α1A and α1D) and angiotensin II receptors (AT1 and AT2) in aorta of rats after 4 weeks of the onset of diabetes. In order to be able to examine the expression of these receptors, immunofluorescence procedure was performed in tunica intima and tunica media of histological sections of aorta. Fluorescence was detected by a confocal microscopy. Our results showed that the receptors are expressed in both tunics, where adrenergic receptors have a higher density in tunica intima and tunica media of SHR compared with WKY; meanwhile, the expression of angiotensin II receptors is not modified in both groups of rats. On the other hand, the results showed that diabetes produced an increase or a decrease in the expression of receptors that is not associated to a specific type of receptor, vascular region, or strain of rat. In conclusion, diabetes and hypertension modify the expression of the receptors in tunica intima and tunica media of aorta in a different way.

  19. Role of angiotensin II and vasopressin receptors within the supraoptic nucleus in water and sodium intake induced by the injection of angiotensin II into the medial septal area

    Directory of Open Access Journals (Sweden)

    Antunes V.R.

    1998-01-01

    Full Text Available In this study we investigated the effects of the injection into the supraoptic nucleus (SON of non-peptide AT1- and AT2-angiotensin II (ANG II receptor antagonists, DuP753 and PD123319, as well as of the arginine-vasopressin (AVP receptor antagonist d(CH25-Tyr(Me-AVP, on water and 3% NaCl intake induced by the injection of ANG II into the medial septal area (MSA. The effects on water or 3% NaCl intake were assessed in 30-h water-deprived or in 20-h water-deprived furosemide-treated adult male rats, respectively. The drugs were injected in 0.5 ml over 30-60 s. Controls were injected with a similar volume of 0.15 M NaCl. Antagonists were injected at doses of 20, 80 and 180 nmol. Water and sodium intake was measured over a 2-h period. Previous administration of the AT1 receptor antagonist DuP753 into the SON decreased water (65%, N = 10, P<0.01 and sodium intake (81%, N = 8, P<0.01 induced by the injection of ANG II (10 nmol into the MSA. Neither of these responses was significantly changed by injection of the AT2-receptor antagonist PD123319 into the SON. On the other hand, while there was a decrease in water intake (45%, N = 9, P<0.01, ANG II-induced sodium intake was significantly increased (70%, N = 8, P<0.01 following injection of the V1-type vasopressin antagonist d(CH25-Tyr(Me-AVP into the SON. These results suggest that both AT1 and V1 receptors within the SON may be involved in water and sodium intake induced by the activation of ANG II receptors within the MSA. Furthermore, they do not support the involvement of MSA AT2 receptors in the mediation of these responses.

  20. Specific single chain variable fragment (ScFv) antibodies to angiotensin II AT(2) receptor: evaluation of the angiotensin II receptor expression in normal and tumor-bearing mouse lung.

    Science.gov (United States)

    Tamura, Masaaki; Yan, Heping; Zegarra-Moro, Ofelia; Edl, Jennifer; Oursler, Stephanie; Chard-Bergstrom, Cindy; Andrews, Gordon; Kanehira, Tsutomu; Takekoshi, Susumu; Mernaugh, Ray

    2008-08-01

    To gain insight into the mechanism by which angiotensin II type 2 receptor (AT(2)) regulates carcinogen-induced lung tumorigenesis, we have newly developed anti-AT(2) single chain variable fragment (ScFv) antibodies using a rodent phage-displayed recombinant antibody library with various peptide fragments of the receptor protein, and investigated the expression of the AT(2) receptor protein. The specificity of the antibodies was verified using AT(2) over-expressing COS-7 cells and AT(2) naturally expressing PC12W cells. In control wild type mouse lung, a stronger immunoreactivity was observed in bronchial epithelial cells. A moderate immunoreactivity was detected in pulmonary vascular walls and vascular endothelial cells. In the lungs possessing tobacco-specific nitrosamine (NNK)-induced tumors, significantly increased AT(2) and AT(1 )immunostaining was observed in adenomatous lesions. These data suggest that the increase in both receptors' expression in the alveolar epithelial cells may be accompanied with the onset of NNK-induced tumorigenesis and hence play important roles in lung tumorigenesis.

  1. Common angiotensin receptor blockers may directly modulate the immune system via VDR, PPAR and CCR2b

    Directory of Open Access Journals (Sweden)

    Lee Robert E

    2006-01-01

    Full Text Available Abstract Background There have been indications that common Angiotensin Receptor Blockers (ARBs may be exerting anti-inflammatory actions by directly modulating the immune system. We decided to use molecular modelling to rapidly assess which of the potential targets might justify the expense of detailed laboratory validation. We first studied the VDR nuclear receptor, which is activated by the secosteroid hormone 1,25-dihydroxyvitamin-D. This receptor mediates the expression of regulators as ubiquitous as GnRH (Gonadatrophin hormone releasing hormone and the Parathyroid Hormone (PTH. Additionally we examined Peroxisome Proliferator-Activated Receptor Gamma (PPARgamma, which affects the function of phagocytic cells, and the C-CChemokine Receptor, type 2b, (CCR2b, which recruits monocytes to the site of inflammatory immune challenge. Results Telmisartan was predicted to strongly antagonize (Ki≈0.04nmol the VDR. The ARBs Olmesartan, Irbesartan and Valsartan (Ki≈10 nmol are likely to be useful VDR antagonists at typical in-vivo concentrations. Candesartan (Ki≈30 nmol and Losartan (Ki≈70 nmol may also usefully inhibit the VDR. Telmisartan is a strong modulator of PPARgamma (Ki≈0.3 nmol, while Losartan (Ki≈3 nmol, Irbesartan (Ki≈6 nmol, Olmesartan and Valsartan (Ki≈12 nmol also seem likely to have significant PPAR modulatory activity. Olmesartan andIrbesartan (Ki≈9 nmol additionally act as antagonists of a theoretical modelof CCR2b. Initial validation of this CCR2b model was performed, and a proposed model for the AngiotensinII Type1 receptor (AT2R1 has been presented. Conclusion Molecular modeling has proven valuable to generate testable hypotheses concerning receptor/ligand binding and is an important tool in drug design. ARBs were designed to act as antagonists for AT2R1, and it was not surprising to discover their affinity for the structurally similar CCR2b. However, this study also found evidence that ARBs modulate the

  2. Angiotensin receptor blockade recovers hepatic UCP2 expression and aconitase and SDH activities and ameliorates hepatic oxidative damage in insulin resistant rats.

    Science.gov (United States)

    Montez, Priscilla; Vázquez-Medina, José Pablo; Rodríguez, Rubén; Thorwald, Max A; Viscarra, José A; Lam, Lisa; Peti-Peterdi, Janos; Nakano, Daisuke; Nishiyama, Akira; Ortiz, Rudy M

    2012-12-01

    Metabolic syndrome (MetS) is commonly associated with elevated renin-angiotensin system, oxidative stress, and steatohepatitis with down-regulation of uncoupling proteins (UCPs). However, the mechanisms linking renin-angiotensin system, steatosis, and UCP2 to hepatic oxidative damage during insulin resistance are not described. To test the hypothesis that angiotensin receptor activation contributes to decreased hepatic UCP2 expression and aconitase activity and to increased oxidative damage after increased glucose intake in a model of MetS, lean and obese Long Evans rats (n = 10/group) were randomly assigned to the following groups: 1) untreated Long Evans Tokushima Otsuka (lean, strain control), 2) untreated Otsuka Long Evans Tokushima Fatty (OLETF) (MetS model), 3) OLETF + angiotensin receptor blocker (ARB) (10 mg olmesartan/kg·d × 6 wk), 4) OLETF + high glucose (HG) (5% in drinking water × 6 wk), and 5) OLETF + ARB + HG (ARB/HG × 6 wk). HG increased body mass (37%), plasma triglycerides (TGs) (35%), plasma glycerol (87%), plasma free fatty acids (28%), and hepatic nitrotyrosine (74%). ARB treatment in HG decreased body mass (12%), plasma TG (15%), plasma glycerol (23%), plasma free fatty acids (14%), and hepatic TG content (42%), suggesting that angiotensin receptor type 1 (AT1) activation and increased adiposity contribute to the development of obesity-related dyslipidemia. ARB in HG also decreased hepatic nitrotyrosine and increased hepatic UCP2 expression (59%) and aconitase activity (40%), as well as antioxidant enzyme activities (50-120%), suggesting that AT1 activation also contributes to protein oxidation, impaired lipid metabolism, and antioxidant metabolism in the liver. Thus, in addition to promoting obesity-related hypertension, AT1 activation may also impair lipid metabolism and antioxidant capacity, resulting in steatosis via decreased UCP2 and tricarboxylic acid cycle activity.

  3. Synthesis and evaluation of novel angiotensin II receptor 1 antagonists as anti-hypertension drugs.

    Science.gov (United States)

    Bao, Xiaolu; Zhu, Weibo; Zhang, Ruijing; Wen, Caihong; Wang, Li; Yan, Yijia; Tang, Hesheng; Chen, Zhilong

    2016-05-01

    Three new angiotensin II receptor 1 antagonists, 1, 2 and 3 were designed, synthesized and evaluated. The AT1 receptor-binding assays in vitro showed that all the synthesized compounds had nanomolar affinity for the AT1 receptor. From which compound 3 was found to be the most potent ligands with an IC50 value of 2.67±0.23 nM. Biological evaluation in vivo revealed that all the compounds could cause significant decrease on MBP in a dose dependent manner in spontaneously hypertensive rats, and compound 3 especially showed an efficient and long-lasting effect in reducing blood pressure, whose maximal response lowered 41 mmHg of MBP at 10mg/kg and 62 mmHg at 15 mg/kg after oral administration, the significant anti-hypertensive effect lasted beyond 12 h, which is better than the reference compound losartan. The pharmacokinetic experiments showed that compound 3 could be absorbed efficiently and metabolized smoothly both in blood and in tissues in Wistar rats. The acute toxicity assay suggested that it has low toxicity with the LD50 value of 2974.35 mg/kg. These results demonstrate that compound 3 is a potent angiotensin AT1 receptor antagonist which could be considered as a novel anti-hypertension candidate and deserved for further investigation.

  4. Left ventricular mass in relation to genetic variation in angiotensin II receptors, renin system genes, and sodium excretion.

    Science.gov (United States)

    Kuznetsova, Tatiana; Staessen, Jan A; Thijs, Lutgarde; Kunath, Christiane; Olszanecka, Agnieszka; Ryabikov, Andrew; Tikhonoff, Valérie; Stolarz, Katarzyna; Bianchi, Giuseppe; Casiglia, Edoardo; Fagard, Robert; Brand-Herrmann, Stefan-Martin; Kawecka-Jaszcz, Kalina; Malyutina, Sofia; Nikitin, Yuri; Brand, Eva

    2004-10-26

    In the European Project On Genes in Hypertension (EPOGH), we investigated in 3 populations to what extent left ventricular mass (LVM) was associated with genetic variation in the angiotensin II receptors type 1 (AGTR1 A1166C) and type 2 (AGTR2 G1675A) while accounting for possible gene-gene interactions with the angiotensin-converting enzyme (ACE D/I) and angiotensinogen (AGT -532C/T) polymorphisms. We randomly recruited 221 nuclear families (384 parents, 431 offspring) in Cracow (Poland), Novosibirsk (Russia), and Mirano (Italy). Echocardiographic LVM was indexed to body surface area, adjusted for covariates, and subjected to multivariate analyses using generalized estimating equations and quantitative transmission disequilibrium tests in a population-based and family-based approach, respectively. For AGTR1 and AGTR2, there was no heterogeneity in the phenotype-genotype relations across populations. LVM index was unrelated to the AGTR1 A1166C polymorphism. In men, in the population- and family-based analyses, the allelic effects of the AGTR2 polymorphism on LVM index differed (P=0.01) according to sodium excretion. In women, this gene-environment interaction did not reach statistical significance. In untreated men, LVM index (4.2 g/m2 per 100 mmol) and left ventricular internal diameter (0.73 mm/100 mmol) increased (Pinfluence LVM and that salt intake modulates these genetic effects.

  5. Angiotensin-(1-12) requires angiotensin converting enzyme and AT1 receptors for cardiovascular actions within the solitary tract nucleus.

    Science.gov (United States)

    Arnold, Amy C; Isa, Katsunori; Shaltout, Hossam A; Nautiyal, Manisha; Ferrario, Carlos M; Chappell, Mark C; Diz, Debra I

    2010-09-01

    The novel peptide, angiotensin (ANG)-(1-12), elicits a systemic pressor response and vasoconstriction. These effects are blocked by ANG converting enzyme (ACE) inhibitors or AT(1) receptor antagonists, suggesting a role as an ANG II precursor. However, ANG-(1-12) can serve as a substrate for either ANG II or ANG-(1-7) formation, depending on the local tissue enzymes. Although levels of ANG-(1-12) are higher than ANG I or ANG II in brain, the role and processing of this peptide for autonomic control of heart rate (HR) has yet to be considered. Thus we examined the effects of nucleus tractus solitarii (NTS) microinjection of ANG-(1-12) on baroreflex sensitivity for control of HR, resting arterial pressure (AP) and HR, and indexes of sympathovagal balance in urethane/chloralose anesthetized Sprague-Dawley rats. NTS injection of ANG-(1-12) (144 fmol/120 nl) significantly impaired the evoked baroreflex sensitivity to increases in AP [n = 7; 1.06 +/- 0.06 baseline vs. 0.44 +/- 0.07 ms/mmHg after ANG-(1-12)], reduced the vagal component of spontaneous baroreflex sensitivity and HR variability, and elicited a transient depressor response (P < 0.05). NTS pretreatment with an AT(1) receptor antagonist or ACE inhibitor prevented ANG-(1-12)-mediated autonomic and depressor responses. ANG-(1-12) immunostaining was observed in cells within the NTS of Sprague-Dawley rats, providing a potential intracellular source for the peptide. However, acute NTS injection of an ANG-(1-12) antibody did not alter resting baroreflex sensitivity, AP, or HR in these animals. Collectively, these findings suggest that exogenous ANG-(1-12) is processed to ANG II for cardiovascular actions at AT(1) receptors within the NTS. The lack of acute endogenous ANG-(1-12) tone for cardiovascular regulation in Sprague-Dawley rats contrasts with chronic immunoneutralization in hypertensive rats, suggesting that ANG-(1-12) may be activated only under hypertensive conditions.

  6. Angiotensin-(1–12) requires angiotensin converting enzyme and AT1 receptors for cardiovascular actions within the solitary tract nucleus

    Science.gov (United States)

    Arnold, Amy C.; Isa, Katsunori; Shaltout, Hossam A.; Nautiyal, Manisha; Ferrario, Carlos M.; Chappell, Mark C.

    2010-01-01

    The novel peptide, angiotensin (ANG)-(1–12), elicits a systemic pressor response and vasoconstriction. These effects are blocked by ANG converting enzyme (ACE) inhibitors or AT1 receptor antagonists, suggesting a role as an ANG II precursor. However, ANG-(1–12) can serve as a substrate for either ANG II or ANG-(1–7) formation, depending on the local tissue enzymes. Although levels of ANG-(1–12) are higher than ANG I or ANG II in brain, the role and processing of this peptide for autonomic control of heart rate (HR) has yet to be considered. Thus we examined the effects of nucleus tractus solitarii (NTS) microinjection of ANG-(1–12) on baroreflex sensitivity for control of HR, resting arterial pressure (AP) and HR, and indexes of sympathovagal balance in urethane/chloralose anesthetized Sprague-Dawley rats. NTS injection of ANG-(1–12) (144 fmol/120 nl) significantly impaired the evoked baroreflex sensitivity to increases in AP [n = 7; 1.06 ± 0.06 baseline vs. 0.44 ± 0.07 ms/mmHg after ANG-(1–12)], reduced the vagal component of spontaneous baroreflex sensitivity and HR variability, and elicited a transient depressor response (P < 0.05). NTS pretreatment with an AT1 receptor antagonist or ACE inhibitor prevented ANG-(1–12)-mediated autonomic and depressor responses. ANG-(1–12) immunostaining was observed in cells within the NTS of Sprague-Dawley rats, providing a potential intracellular source for the peptide. However, acute NTS injection of an ANG-(1–12) antibody did not alter resting baroreflex sensitivity, AP, or HR in these animals. Collectively, these findings suggest that exogenous ANG-(1–12) is processed to ANG II for cardiovascular actions at AT1 receptors within the NTS. The lack of acute endogenous ANG-(1–12) tone for cardiovascular regulation in Sprague-Dawley rats contrasts with chronic immunoneutralization in hypertensive rats, suggesting that ANG-(1–12) may be activated only under hypertensive conditions. PMID:20562338

  7. Cognitive enhancing effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on learning and memory

    Directory of Open Access Journals (Sweden)

    V S Nade

    2015-01-01

    Conclusion: The results suggest that the cognitive enhancing effect of ACEI and ARBs may be due to inhibition of AChE or by regulation of antioxidant system or increase in formation of angiotensin IV.

  8. Impact of drug price adjustments on utilization of and expenditures on angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in Taiwan

    Directory of Open Access Journals (Sweden)

    Huang Shiou-Huei

    2012-05-01

    Full Text Available Abstract Background A previous study has suggested that drug price adjustments allow physicians in Taiwan to gain greater profit by prescribing generic drugs. To better understand the effect of price adjustments on physician choice, this study used renin-angiotensin drugs (including angiotensin-converting enzyme inhibitors [ACEIs] and angiotensin receptor blockers [ARBs] to examine the impact of price adjustments on utilization of and expenditures on patented and off-patent drugs with the same therapeutic indication. Methods Using the Taiwan’s Longitudinal Health Insurance Database (2005, we identified 147,157 patients received ACEIs and/or ARBs between 1997 and 2008. The annual incident and prevalent users of ACEIs, ARBs and overall renin-angiotensin drugs were examined. Box-Tiao intervention analysis was applied to assess the impact of price adjustments on monthly utilization of and expenditures on these drugs. ACEIs were divided into patented and off-patent drugs, off-patent ACEIs were further divided into original brands and generics, and subgroup analyses were performed. Results The number of incident renin-angiotensin drug users decreased over the study period. The number of prevalent ARB users increased and exceeded the cumulative number of first-time renin-angiotensin drug users starting on ARBs, implying that some patients switched from ACEIs to ARBs. After price adjustments, long term trend increases in utilization were observed for patented ACEIs and ARBs; a long-term trend decrease was observed for off-patent ACEIs; long-term trend change was not significant for overall renin-angiotensin drugs. Significant long-term trend increases in expenditures were observed for patented ACEIs after price adjustment in 2007 (200.9%, p = 0.0088 and in ARBs after price adjustments in 2001 (173.4%, p  Conclusions Price adjustments did not achieve long-term cost savings for overall renin-angiotensin drugs. Possible switching from ACEIs to ARBs

  9. Angiotensin receptor neprilysin inhibition in heart failure: mechanistic action and clinical impact.

    Science.gov (United States)

    Buggey, Jonathan; Mentz, Robert J; DeVore, Adam D; Velazquez, Eric J

    2015-09-01

    Heart failure (HF) is an increasingly common syndrome associated with high mortality and economic burden, and there has been a paucity over the past decade of new pharmacotherapies that improve outcomes. However, recent data from a large randomized controlled trial compared the novel agent LCZ696, a dual-acting angiotensin receptor blocker and neprilysin inhibitor (ARNi), with the well established angiotensin-converting enzyme (ACE) inhibitor enalapril and found significant reduction in mortality among the chronic reduced ejection fraction HF population. Preclinical and clinical data suggest that neprilysin inhibition provides beneficial outcomes in HF patients by preventing the degradation of natriuretic peptides and thereby promoting natriuresis and vasodilatation and counteracting the negative cardiorenal effects of the up-regulated renin-angiotensin-aldosterone system. Agents such as omapatrilat combined neprilysin and ACE inhibition but had increased rates of angioedema. Goals of an improved safety profile provided the rationale for the development of the ARNi LCZ696. Along with significant reductions in mortality and hospitalizations, clinical trials suggest that LCZ696 may improve surrogate markers of HF severity. In this paper, we review the preclinical and clinical data that led to the development of LCZ696, the understanding of the underlying mechanistic action, and the robust clinical impact that LCZ696 may have in the near future. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Influence of angiotensin II receptor subtypes of the paraventricular nucleus on the physiological responses induced by angiotensin II injection into the medial septal area

    Directory of Open Access Journals (Sweden)

    Saad Wilson Abrão

    2003-01-01

    Full Text Available OBJECTIVE: We determined the effects of losartan and PD 123319 (antagonists of the AT1 and AT2 angiotensin receptors, respectively, and [Sar¹, Ala8] ANG II (a relatively peptide antagonist of angiotensin receptors injected into the paraventricular nucleus (PVN on water and 3% NaCl intake, and the diuretic, natriuretic, and pressor effects induced by administration of angiotensin II (ANG II into the medial septal area (MSA of conscious rats. METHODS: Holtzman rats were used . Animals were anesthetized with tribromoethanol (20 mg per 100 grams of body weight, ip. A stainless steel guide cannula was implanted into the MSA and PVN. All drugs were injected in 0.5-mul volumes for 10-15 seconds. Seven days after brain surgery, water and 3% NaCl intake, urine and sodium excretion, and arterial blood pressure were measured. RESULTS: Losartan (40 nmol and [Sar¹, Ala8] ANG II (40 nmol completely eliminated whereas PD 123319 (40 nmol partially blocked the increase in water and sodium intake and the increase in arterial blood pressure induced by ANG II (10 nmol injected into the MSA. The PVN administration of PD 123319 and [Sar¹, Ala8] ANG II blocked whereas losartan attenuated the diuresis and natriuresis induced by MSA administration of ANG II. CONCLUSION: MSA involvement with PVN on water and sodium homeostasis and arterial pressure modulation utilizing ANGII receptors is suggested.

  11. Incidence and influencing factors of aldosterone breakthrough during therapy with angiotensinreceptor bockers alone,or combined with angiotensin-converting enzyme inhibitors in patients with non-diabetic nephropathy

    Institute of Scientific and Technical Information of China (English)

    梁敏

    2013-01-01

    Objective To investigate the incidence and influen-cing factors of aldosterone breakthrough during therapy with angiotensinreceptor blockers(ARB) alone,or combined with angiotensin-converting enzyme inhibitors(ACEI) in Chinese patients with non-diabetic

  12. Angiotensin receptors and actions in guinea pig enteric nervous system.

    Science.gov (United States)

    Wang, Guo-Du; Wang, Xi-Yu; Hu, Hong-Zhen; Fang, Xiu-Cai; Liu, Sumei; Gao, Na; Xia, Yun; Wood, Jackie D

    2005-09-01

    Actions of ANG II on electrical and synaptic behavior of enteric neurons in the guinea pig small intestine were studied. Exposure to ANG II depolarized the membrane potential and elevated neuronal excitability. The number of responding neurons was small, with responses to ANG II in 32% of submucosal neurons and 25% of myenteric neurons. Hyperpolarizing responses were evoked by ANG II in 45% of the neurons. The hyperpolarizing responses were suppressed by alpha2-noradrenergic receptor antagonists, which suggested that the hyperpolarizing responses reflected stimulation of norepinephrine release from sympathetic neurons. Exposure to ANG II enhanced the amplitude and prolonged the duration of noradrenergic inhibitory postsynaptic potentials and suppressed the amplitude of both fast and slow excitatory postsynaptic potentials. The selective ANG II(1) receptor (AT1R) antagonists, ZD-7115 and losartan, but not a selective AT2R antagonist (PD-123319), suppressed the actions of ANG II. Western blot analysis and RT-PCR confirmed expression of AT1R protein and the mRNA transcript for the AT1R in the enteric nervous system. No expression of AT2R protein or mRNA was found. Immunoreactivity for AT1R was expressed by the majority of neurons in the gastric antrum and small and large intestine. AT1R immunoreactivity was coexpressed with calbindin, choline acetyltransferase, calretinin, neuropeptide Y, and nitric oxide synthase in subpopulations of neurons. The results suggest that formation of ANG II might have paracrine-like actions in the enteric nervous system, which include alterations in neuronal excitability and facilitated release of norepinephrine from sympathetic postganglionic axons. The enhanced presence of norepinephrine is expected to suppress fast and slow excitatory neurotransmission in the enteric microcircuits and to suppress neurogenic mucosal secretion.

  13. Effects of angiotensin-converting enzyme inhibitor, captopril, on bone of mice with streptozotocin-induced type 1 diabetes.

    Science.gov (United States)

    Diao, Teng-Yue; Pan, Hai; Gu, Sa-Sa; Chen, Xi; Zhang, Fang-Yi; Wong, Man-Sau; Zhang, Yan

    2014-05-01

    There are contradictory results about the effect of angiotensin-converting enzyme inhibitors (ACEIs) on bone. This study was performed to address the skeletal renin-angiotensin system (RAS) activity and the effects of the ACEI, captopril, on the bone of streptozotocin-induced type 1 diabetic mice. Histochemical assessment on bone paraffin sections was conducted by Safranin O staining and tartrate-resistant acid phosphatase staining. Micro-computed tomography was performed to analyze bone biological parameters. Gene and protein expression were determined by real-time polymerase chain reaction and immunoblotting, respectively. Type 1 diabetic mice displayed osteopenia phenotype and captopril treatment showed no osteoprotective effects in diabetic mice as shown by the reduction of bone mineral density, trabecular thickness and bone volume/total volume. The mRNA expression of ACE and renin receptor, and the protein expression of renin and angiotensin II were markedly up-regulated in the bone of vehicle-treated diabetic mice compared to those of non-diabetic mice, and these molecular changes of skeletal RAS components were effectively inhibited by treatment with captopril. However, treatment with captopril significantly elevated serum tartrate-resistant acid phosphatase 5b levels, reduced the ratio of osteoprotegerin/receptor activator of nuclear factor-κB ligand expression, increased carbonic anhydrase II mRNA expression and the number of matured osteoclasts and decreased transforming growth factor-β and osteocalcin mRNA expression in the tibia compared to those of diabetic mice. The present study demonstrated that the use of the ACEI, captopril, has no beneficial effect on the skeletal biological properties of diabetic mice. However, this could be attributed, at least partially, to its suppression of osteogenesis and stimulation of osteoclastogenesis, even though it could effectively inhibit high activity of local RAS in the bone of diabetic mice.

  14. Comparative effectiveness of olmesartan and other angiotensin receptor blockers in diabetes mellitus: retrospective cohort study.

    Science.gov (United States)

    Padwal, Raj; Lin, Mu; Etminan, Mahyar; Eurich, Dean T

    2014-05-01

    Olmesartan has been linked with increased risk of cardiovascular mortality and sprue-like enteropathy. We compared outcomes between olmesartan and other angiotensin receptor blockers in a large clinical registry of patients with diabetes mellitus. A retrospective cohort analysis using nationwide US-integrated insurance and laboratory claims was performed in 45 185 incident diabetic angiotensin receptor blocker users, including 10 370 (23%) olmesartan users. Hazard ratios were computed using time-dependant Cox models adjusted for sociodemographic characteristics, comorbidities, laboratory data, drug use, healthcare utilization, and the propensity to receive olmesartan. Blood pressure data were unavailable. Subjects were followed up for 116 721 patient-years. The primary end point was all-cause hospitalization or all-cause mortality and occurred in 10 915 (24%) patients. Average age was 54.3±9.6 years, 52% were men, 17% had cardiovascular disease, and 10% chronic kidney disease. Compared with other angiotensin receptor blockers, the adjusted hazard for olmesartan was 0.99 (95% confidence interval, 0.94-1.05) for all-cause hospitalization and mortality; 0.90 (0.62-1.30) for all-cause mortality; 0.99 (0.94-1.05) for all-cause hospital admission; 0.88 (0.78-1.00) for cardiovascular disease-related admission, and 1.09 (0.98-1.20) for gastrointestinal disease-related hospitalization in the overall cohort. Olmesartan use was associated with an adjusted hazard for the primary outcome of 1.11 (0.99-1.24) in subjects with history of cardiovascular disease and 1.21 (1.04-1.41) in subjects with chronic kidney disease. In conclusion, there is no robust signal for harm with olmesartan use. Risk may be increased in kidney disease; thus, given the widespread availability of alternate agents, olmesartan should be used with caution in this subgroup pending further study.

  15. Glucocorticoid-induced fetal programming alters the functional complement of angiotensin receptor subtypes within the kidney.

    Science.gov (United States)

    Gwathmey, TanYa M; Shaltout, Hossam A; Rose, James C; Diz, Debra I; Chappell, Mark C

    2011-03-01

    We examined the impact of fetal programming on the functional responses of renal angiotensin receptors. Fetal sheep were exposed in utero to betamethasone (BMX; 0.17 mg/kg) or control (CON) at 80 to 81 days gestation with full-term delivery. Renal nuclear and plasma membrane fractions were isolated from sheep age 1.0 to 1.5 years for receptor binding and fluorescence detection of reactive oxygen species (ROS) or nitric oxide (NO). Mean arterial blood pressure and blood pressure variability were significantly higher in the BMX-exposed adult offspring versus CON sheep. The proportion of nuclear AT(1) receptors sensitive to losartan was 2-fold higher (67 ± 6% vs 27 ± 9%; Pprogramming.

  16. The angiotensin-receptor blocker candesartan for treatment of acute stroke (SCAST)

    DEFF Research Database (Denmark)

    Sandset, Else Charlotte; Bath, Philip M W; Boysen, Gudrun;

    2011-01-01

    blood pressure. METHODS: Participants in this randomised, placebo-controlled, double-blind trial were recruited from 146 centres in nine north European countries. Patients older than 18 years with acute stroke (ischaemic or haemorrhagic) and systolic blood pressure of 140 mm Hg or higher were included......%) patients taking candesartan and 13 (1%) allocated placebo. INTERPRETATION: There was no indication that careful blood-pressure lowering treatment with the angiotensin-receptor blocker candesartan is beneficial in patients with acute stroke and raised blood pressure. If anything, the evidence suggested...

  17. Randomised trial on episodic cluster headache with an angiotensin II receptor blocker

    DEFF Research Database (Denmark)

    Tronvik, Erling; Wienecke, Troels; Monstad, Inge

    2013-01-01

    OBJECTIVES: The aim of this study was to evaluate the angiotensin II receptor antagonist candesartan as prophylactic medication in patients with episodic cluster headache. METHODS: This study comprised a prospective, placebo-controlled, double-blind, parallel-designed trial performed in seven...... centres in Scandinavia. Forty (40) patients with episodic cluster headache (ICHD-2) were recruited and randomised over a five-year period to placebo or 16 mg candesartan in the first week, and placebo or 32 mg candesartan in the second and third week. RESULTS: The number of cluster headache attacks...

  18. The relationship between angiotensintype 1 receptor gene A1166C polymorphism and chronic heart failure%血管紧张素Ⅱ1型受体基因A1166C多态性与慢性心力衰竭的相关性研究

    Institute of Scientific and Technical Information of China (English)

    郑晓明; 刘俊双; 李宏芬; 刘英

    2008-01-01

    Objective To investigate the relationship of angiotensin Ⅱ typel receptor gene A1166C polymorphism and chronic heart failure.Method Polymerase chain reaction and restriction fragment length polymorphism(PCR-RFLP)was used to detect the A1166C polymorphism of AT1R gene of 135 chronic heart failure patients and 121 controls.Results The genotype frequency of the patients and controls of AA,AC,CC were 87.6%.12.4%,0%and 87.6%,11.6%,0.8%respectively.Allele frequency of the patients and controls were 93.8%,6.2%and 93.6%,6.4%respectively.There was no significant difference of the frequency of AT1R genotype and allele between CHF and controls(P>0.05).Conclusion Angiotensintype 1 receptor gene A1166C polymorphism is not associated with CHF.%目的 研究血管紧张素Ⅱ1型受体(AT1R)基因A1166C多态性与慢性心力衰竭的相关性.方法 采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术检测135例慢性心力衰竭患者和121例正常对照者的AT1R基因A1166C位点的基因型.结果 病例组AA、AC、CC基因型频率为87.6%、12.4%、0,等位基因频率为93.8%、6.2%;正常对照组AA、AC、CC基因型频率为87.6%、11.6%、0.8%,等位基因频率为93.6%、6.4%;病例组基因型及等位基因频率与正常对照组比较差异均无统计学意义(均P>0.05).结论AT1R基因A1166C多态性与慢性心力衰竭无关.

  19. [Assessment of the utilization of angiotensin receptor blockers in hypertension].

    Science.gov (United States)

    Peña Cabia, S; Ricote Lobera, I; Santos Mena, B; Hidalgo Correas, F J; Climent Florez, B; García Díaz, B

    2013-01-01

    Objetivo: Evaluar en nuestra área de Salud el grado en que la utilización de antagonistas de los receptores de la angiotensina II (ARA-II) se ajusta a los criterios propuestos por la Comunidad Autónoma de Madrid (CAM) antes de la instauración del «Plan de Actuación de ARA-II». Estudiar las indicaciones para las que se prescriben e identificar aquellos factores que han podido influir en su prescripción. Métodos: Estudio de utilización de medicamentos del tipo indicación- prescripción, descriptivo y transversal, en el que se seleccionaron pacientes con hipertensión arterial y en tratamiento con ARA-II ingresados en un Hospital General Universitario durante un periodo de estudio de 3 meses. De acuerdo con las situaciones clínicas recogidas en el Documento de la CAM «Criterios para establecer el lugar en la terapéutica de los antagonistas de los receptores de la angiotensina II», se calculó el porcentaje de pacientes con «prescripción adecuada» y «prescripción no adecuada» de ARA-II y se analizó si la edad y el sexo tenían influencia en el tipo de prescripción o en las principales indicaciones para las que se prescribieron. Resultados: De los 153 pacientes que se incluyeron en el estudio, el 67,3% tuvieron una «prescripción no adecuada», el 47,6% de ellos por prescripción de ARA-II como primer fármaco antagonista del sistema renina angiotensina aldosterona y el 34,0% por mal control de la tensión arterial con inhibidores de la enzima convertidora de angiotensina (IECA). No se encontraron diferencias estadísticamente significativas por edad o sexo en cuanto al tipo de prescripción o en las principales indicaciones para las que se prescribieron. Conclusiones: La adecuación a los criterios de uso del Documento de ARA-II se produjo en el 32,7% de los casos. Además, no se observó que factores como la edad y el sexo influyeran en el tipo de prescripción. Asimismo, se evidenciaron percep-

  20. ANGIOTENSIN RECEPTOR BLOCKERS WITH PLEIOTROPIC PROPERTIES: A NEW STANDARD IN CARDIOVASCULAR RISK MANAGEMENT AND TREATMENT OF HYPERTENSION

    Directory of Open Access Journals (Sweden)

    V. I. Podzolkov

    2017-01-01

    Full Text Available An increase in the activity of the renin-angiotensin-aldosterone system is one of the most important mechanisms for the realization of the cardiovascular continuum. The role that angiotensin receptor blockers play in achieving target figures of blood pressure and reducing cardiovascular risk is discussed. The importance of pleiotropic properties of angiotensin receptor blockers (in particular, activation of peroxisome proliferator-activated receptors gamma – PPAR-γ in the management of patients with insulin resistance, obesity, dyslipidemia is also covered. The evidence base for the use of telmisartan as a drug with pleiotropic effect in patients with arterial hypertension and associated diseases (diabetes mellitus, obesity, renal dysfunction is discussed. 

  1. miR-155 functions downstream of angiotensin II receptor subtype 1 and calcineurin to regulate cardiac hypertrophy.

    Science.gov (United States)

    Yang, Yong; Zhou, Yong; Cao, Zheng; Tong, Xin Zhu; Xie, Hua Qiang; Luo, Tao; Hua, Xian Ping; Wang, Han Qin

    2016-09-01

    Cardiac hypertrophy is characterized by maladaptive tissue remodeling that may lead to heart failure or sudden death. MicroRNAs (miRs) are negative regulators of angiotensin II and the angiotensin II receptor subtype 1 (AGTR1), which are two components involved in cardiac hypertrophy. In the present study, the interaction between angiotensin II receptor subtype 1 (AGTR1) signaling and miR-155 was investigated. Rat H9C2 (2-1) cardiomyocytes were transfected with miR-155 analogues or inhibitors, then stimulated with angiotensin II to induce cardiac hypertrophy. miR-155 expression was revealed to be altered following transfection with chemically-modified miR-155 analogues and inhibitors in rat cardiomyocytes. In cell cardiac hypertrophy models, the cell surface area, AGTR1, atrial natriuretic peptide and myosin heavy chain-β mRNA expression levels were revealed to be lower in cells stimulated with miR-155 analogue-transfected cells treated with angiotensin II compared with cells stimulated with angiotensin alone (PAGTR1 and suppressing the calcium signaling pathways activated by AGTR1.

  2. The effectiveness and safety of angiotensin-converting enzyme inhibition or receptor blockade in vascular diseases in patients with hemodialysis

    Science.gov (United States)

    Liao, Kuang-Ming; Cheng, Hui-Teng; Lee, Yi-Hsuan; Chen, Chung-Yu

    2017-01-01

    Abstract Patients with end-stage renal disease (ESRD) who are on hemodialysis have high risk of vascular diseases. Our study sought to examine whether angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin type 1 receptor blockers (ARBs) could reduce the frequencies of cardiovascular and cerebrovascular events in patients receiving hemodialysis using the medication possession ratio (MPR) method of analysis. This retrospective cohort study identified cases of ESRD with dialysis from the National Health Insurance Research Database between 1999 and 2006, and used Cox-regression methods to evaluate risk of poor outcomes. Primary outcomes, including death from any cause, and secondary outcomes, including admission for stroke, myocardial infarction, and heart failure, were examined. Compared to the nonuser group, the adjusted HRs for mortality of the nonadherence group and the adherence group were 0.81 (95% CI: 0.76–0.86) and 0.98 (95% CI: 0.86–1.13), respectively. Cardiovascular events were more frequent in patients with ESRD receiving ACEIs /ARBs than in nonusers. Compared with nonusers, the hazard of secondary outcome significantly increased in the nonadherence group or adherence group in 10 years follow-up. Compared with patients with diabetes or chronic kidney disease, patients on hemodialysis may not experience the same cardiovascular and cerebrovascular benefits from ACEIs/ARBs use. PMID:28353612

  3. Cost effectiveness of angiotensin receptor blocker monotherapy in patients with hypertension in the Netherlands : a comparative analysis using clinical trial and drug utilization data

    NARCIS (Netherlands)

    Boersma, C.; Voors, A.A.; Visser, Sipke; de Jong-van den Berg, L.T.W.; Postma, M.J.

    2010-01-01

    Background and Objective: Health gains and related cost savings achieved by optimizing treatment in hypertensive patients is highly important. The aim of this study was to evaluate the costs and cost effectiveness of treatment with angiotensin II receptor antagonists (angiotensin II receptor

  4. Cost effectiveness of angiotensin receptor blocker monotherapy in patients with hypertension in the Netherlands : a comparative analysis using clinical trial and drug utilization data

    NARCIS (Netherlands)

    Boersma, C.; Voors, A.A.; Visser, Sipke; de Jong-van den Berg, L.T.W.; Postma, M.J.

    2010-01-01

    Background and Objective: Health gains and related cost savings achieved by optimizing treatment in hypertensive patients is highly important. The aim of this study was to evaluate the costs and cost effectiveness of treatment with angiotensin II receptor antagonists (angiotensin II receptor blocker

  5. Mas receptor mediates cardioprotection of angiotensin-(1-7) against Angiotensin II-induced cardiomyocyte autophagy and cardiac remodelling through inhibition of oxidative stress.

    Science.gov (United States)

    Lin, Li; Liu, Xuebo; Xu, Jianfeng; Weng, Liqing; Ren, Jun; Ge, Junbo; Zou, Yunzeng

    2016-01-01

    Angiotensin II (Ang II) plays an important role in the onset and development of cardiac remodelling associated with changes of autophagy. Angiotensin1-7 [Ang-(1-7)] is a newly established bioactive peptide of renin-angiotensin system, which has been shown to counteract the deleterious effects of Ang II. However, the precise impact of Ang-(1-7) on Ang II-induced cardiomyocyte autophagy remained essentially elusive. The aim of the present study was to examine if Ang-(1-7) inhibits Ang II-induced autophagy and the underlying mechanism involved. Cultured neonatal rat cardiomyocytes were exposed to Ang II for 48 hrs while mice were infused with Ang II for 4 weeks to induce models of cardiac hypertrophy in vitro and in vivo. LC3b-II and p62, markers of autophagy, expression were significantly elevated in cardiomyocytes, suggesting the presence of autophagy accompanying cardiac hypertrophy in response to Ang II treatment. Besides, Ang II induced oxidative stress, manifesting as an increase in malondialdehyde production and a decrease in superoxide dismutase activity. Ang-(1-7) significantly retarded hypertrophy, autophagy and oxidative stress in the heart. Furthermore, a role of Mas receptor in Ang-(1-7)-mediated action was assessed using A779 peptide, a selective Mas receptor antagonist. The beneficial responses of Ang-(1-7) on cardiac remodelling, autophagy and oxidative stress were mitigated by A779. Taken together, these result indicated that Mas receptor mediates cardioprotection of angiotensin-(1-7) against Ang II-induced cardiomyocyte autophagy and cardiac remodelling through inhibition of oxidative stress. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  6. EFFECT OF ANGIOTENSINRECEPTOR SUBTYPE Ⅰ ON THE FIRING RATE IN CATECHOLAMINERGIC TUMOR CELLS

    Institute of Scientific and Technical Information of China (English)

    Du Jianqing(杜剑青); Sun Chengwen(孙成文); Tang Jingshi (唐敬师); Colin Sumners; Mohan K Raizada

    2003-01-01

    Objective To study the action of brain angiotensin Ⅱ(Ang Ⅱ) receptors and underlying intracellular mechanism in the catecholaminergic system(CATH) Methods Action potentials (APs) of the primary co-cultured catecholaminergic tumor (CATH.a) cells were recorded with the whole-cell patch clamp configuration in current clamp mode. Expression of Ang Ⅱ receptors subtypes (AT1 and AT2) was detected by RT-PCR technique. Results The differentiated CATH.a cells represented a neuron-like characterization. All CATH.a cells expressed mRNA encoding both Ang Ⅱ AT1 and AT2 receptor subtypes. Ang Ⅱ increased the firing rate in the CATH.a cells, which was inhibited completely by addition administration of the AT1 but not AT2 receptor antagonist, and partially by using the inhibitors of signal molecules, U73122 (10 μmol*L-1), or KN-93 (10 μmol*L-1), or calphostin C (10 μmol*L-1). Conclusion Ang Ⅱ increases firing rate in CATH.a cells via AT1 receptor. The CATH.a cells expressing functional AT1 and AT2 receptor subtypes may be of general utility for the study of the Ang Ⅱ receptor-induced modulation of brain catecholaminergic system.

  7. Use of different types of angiotensin converting enzyme inhibitors and mortality in systolic heart failure

    DEFF Research Database (Denmark)

    Svanström, Henrik; Pasternak, Björn; Melbye, Mads;

    2015-01-01

    BACKGROUND: Angiotensin converting enzyme-inhibitors (ACEIs) are the first-line treatment for patients with heart failure (HF) with reduced ejection fraction (EF). The benefit of ACEIs in HF is regarded as a class effect and different types of agents are used interchangeably. However, evidence...

  8. Effects of Autoantibodies Against At1-receptor and Angiotensin II on Refractory Hypertension

    Institute of Scientific and Technical Information of China (English)

    廖玉华; 魏宇淼; 王敏; 董继华; 王朝晖; 苑海涛

    2001-01-01

    Objective The study will explore effects of the autoantibodies against AT1 receptor and angiotensin Ⅱ on the refractory hypertension. Methods Seventy-seven patients (46 men and 31 women) with essential hypertension were divided into groups of refractory hypertension (RH) and hypertension (HT) according to the 1999 WHO -ISH Guidelines for the Management of Hypertension. Forty normotensives (22 men) were recruited as controls.The mean age was 54. 3 ± 13 years old in RH group,53.5±9 years old in HT group and 51.2±11.9years old in normotensives (NT) group. The mean blood pressure was 154.2 ± 9.4/98.4 ± 8.2 mmHg in RH group and 130.1 ±7.6/80.5 ±6.7 mmHg in HT group after combination drug therapy of hypertension for 4 weeks. Blood pressure in NT group was 120. 8 ± 11.7/76. 4 ± 7.2 mmHg. The epitope of the 2nd extracellular loops of AT1 receptor was synthesized and used as antigens to screen the autoantibodies by ELISA. Plasma angiotensin (Ang) Ⅱ were examined by a radioimmunoassay. Results The autoantibodies against AT1 receptor were positive in 18 (46. 15% ) patients with RH, in 4 (10. 5 % ) hypertension and in 3 (7.5 % ) normotensives, P < 0.01. Ang Ⅱwas 57.01 ± 52.63 pmol/L in patients with RH. Both the autoantibodies positive and the Ang Ⅱ increasing were 4 (10. 3 %) cases, both normal were 7 (17.9% ) cases, the autoantibodies positive or Ang Ⅱ in creasing was all of 14 (35.9 % ) cases (χ2 =0. 09,P > 0. 05) There was no relationship between the autoantibodies against AT1 receptor and the angiotensin Ⅱ in refractory hypertension. Conclusion The autoantibodies against AT1 receptor and Ang Ⅱ might be two independent factors in developing of refractory hypertension. The findings suggest that AT1 receptor antagnist used in the treatment of refractory hypertension might have an important value.

  9. Spectrum of mutations in the renin-angiotensin system genes in autosomal recessive renal tubular dysgenesis

    DEFF Research Database (Denmark)

    Gribouval, Olivier; Morinière, Vincent; Pawtowski, Audrey

    2012-01-01

    , pulmonary hypoplasia, and refractory arterial hypotension. The disease is linked to mutations in the genes encoding several components of the renin-angiotensin system (RAS): AGT (angiotensinogen), REN (renin), ACE (angiotensin-converting enzyme), and AGTR1 (angiotensin II receptor type 1). Here, we review...

  10. Fructose rich diet differently affects angiotensin II receptors content in the nucleus and a plasma membrane fraction of visceral adipose tissue.

    Science.gov (United States)

    Bundalo, Maja; Djordjevic, Ana; Bursac, Biljana; Zivkovic, Maja; Koricanac, Goran; Stankovic, Aleksandra

    2017-08-03

    The adipose tissue renin-angiotensin system (RAS) is proposed to be a pathophysiological link between adipose tissue dysregulation and metabolic disorders induced by fructose rich diet (FRD). RAS can act intracellularly. We hypothesized that adipocytes nuclear membranes possess angiotensin receptors type 1 and type 2 (AT1R and AT2R) that couple to nuclear signaling pathways and regulate oxidative gene expression under the FRD. We analyzed the effect of nine-week consumption of 10% fructose solution on biochemical parameters, adipocyte morphology and expression of AT1R, AT2R, AT1R-associated protein (ATRAP), NOX4, MMP-9, and MnSOD in adipose tissue of Wistar rats. We detected AT1R and AT2R in nuclear fraction. FRD decreased protein level of nuclear angiotensin receptors, while increased AT1R and decreased AT2R levels were observed at plasma membrane. FRD increased mRNA level of ATRAP, while MnSOD mRNA and protein levels were decreased. No significant differences were observed for MMP9 and NOX4 mRNA levels. These findings coincide with hyperleptinemia, elevated blood pressure and triglyceride level, as well as with unchanged visceral adipose tissue mass and morphology upon FRD. Besides providing evidence for nuclear localization of angiotensin receptors in visceral adipose tissue, this study also points to the different effect of FRD on AT1R expression in different cellular compartments. Elevated blood pressure and decreased antioxidative capacity in visceral fat of fructose fed rats were accompanied by an increased AT1R level in plasma membrane while upregulation of ATRAP and decrease of nuclear membrane AT1R suggest an increase in capacity for attenuation of excessive AT1R signaling and visceral adiposity.

  11. Association of renin-angiotensin system genes polymorphism with progression of diabetic nephropathy in patients with type 1 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Ilić Vesna

    2014-01-01

    Full Text Available Background/Aim. Diabetic nephropathy (DN as a major microvascular complication of diabetes mellitus (DM include a progressive increase in urinary albumin excretion in association with an increase in blood pressure and to end stage renal failure. Hypertension connected with renin-angiotensin system (RAS hyperactivity and corresponding genotypes, angiotensinogen (AGT, angiotensine-converting enzyme (ACE and angiotensin II type 1 receptor (AT1R, predispose the increasing risk of DN. The aim of this study was to assess the distribution of AGT, ACE and AT1R gene polymorphisms in patients with type 1 DM according to the level of DN and patients clinical characteristics. Methods. The study included 79 type 1 diabetic patients. Inclusion criteria were: age between 20-40, duration of diabetes > 5 years, and no other severe diseases. Clinical characteristics were gained from interviewing the patients. Polymorphism was detected by polymerase chain reaction (PCR and restriction fragment length polymorphism using restriction enzymes Psy I (Tth 111 I and Hae III. Results. The patients with proteinuria compared with normo- and microalbuminuric patients, highly differed in age, diabetes duration, blood pressure level, hypertension, rethynopathy and urinary albumin excretion values (p < 0.001. No statistically significant difference between the groups was found for the ACE and AT1R gene polymorphisms distribution. The presence of TT genotype of the M235T polymorphism was significantly higher in the group with proteinuria (p < 0.05. The patients with hypertension raised nephropathy 5.2 times higher (OR = 5.20, p < 0.05 while carriers of TT allel developed nephropathy 28.38 times higher (OR = 28.389, p < 0.01 than those with MM genotype. Conclusion. Increased association of hypertension and TT angiotensinogen gene polymorphism in patients with diabetes mellitus with proteinuria could be a significant marker of diabetic nephropathy.

  12. Genetic variation and activity of the renin-angiotensin system and severe hypoglycemia in type 1 diabetes

    DEFF Research Database (Denmark)

    Pedersen-Bjergaard, U.; Dhamrait, S.S.; Sethi, A.A.;

    2008-01-01

    BACKGROUND: The deletion-allele of the angiotensin-converting enzyme (ACE) gene and elevated ACE activity are associated with increased risk of severe hypoglycemia in type 1 diabetes. We explored whether genetic and phenotypic variations in other components of the renin-angiotensin system...

  13. Relationship between the bioavailability and molecular properties of angiotensin II receptor antagonists

    Directory of Open Access Journals (Sweden)

    Trbojević Jovana B.

    2016-01-01

    Full Text Available In the present study, we investigated the relationships between several molecular properties and bioavailability data for seven of the most commonly prescribed angiotensin II receptor antagonists (also known as angiotensin II receptor blockers (ARBs or sartans, candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan and valsartan. The molecular descriptors of ARBs are:, aqueous solubility (logS values, polar surface area (PSA, molecular weight (Mw, volume value (Vol, lipophilicity (logP values and the acidity descriptor (pKa1. The respective descriptors were calculated using four different software packages. The relevant bioavailability data were obtained from literature. Among calculated molecular descriptors, simple linear regression analysis showed the best correlation between bioavailability data and the lipophilicity descriptor, logP (R2 = 0.568. Multiple linear regression established good correlations between bioavailability and the lipophilicity descriptor, logP, using the molecular weight, Mw, or the acidity descriptor, pKa1, as an additional, independent variable (with R2 0.661 and 0.682, respectively. Finally, excluding candesartan from the calculations resulted in a very good correlation (R2 = 0.852 between the remaining ARB bioavailability and molecular descriptors MlogP and Mw as independent variables, determined by multiple linear regression. [Projekat Ministarstva nauke Republike Srbije, br. TR34031

  14. Angiotensin receptor antagonists to prevent sudden death in heart failure: does the dose matter?

    Science.gov (United States)

    Francia, Pietro; Palano, Francesca; Tocci, Giuliano; Adduci, Carmen; Ricotta, Agnese; Semprini, Lorenzo; Caprinozzi, Massimo; Balla, Cristina; Volpe, Massimo

    2014-01-01

    International guidelines recommend ICD implantation in patients with severe left ventricular dysfunction of any origin only after careful optimization of medical therapy. Indeed, major randomized clinical trials suggest that suboptimal use of fundamental drugs, such as ACE inhibitors (ACE-i) and beta-blockers, may affect ICD shock-free survival, sudden cardiac death (SCD), and overall mortality. While solid evidence in favour of pharmacological therapy based on ACE-i with or without beta-blockers is available, data on SCD in HF patients treated with angiotensin receptor blockers (ARBs) are limited. The present paper systematically analyses the impact of ARBs on SCD in HF and reviews the contributory role of the renin-angiotensin system (RAS) to the establishment of arrhythmic substrates. The following hypothesis is supported: (1) the RAS is a critical component of the electrical remodelling of the failing myocardium, (2) RAS blockade reduces the risk of SCD, and (3) ARBs represent a powerful tool to improve overall survival and possibly reduce the risk of SCD provided that high doses are employed to achieve optimal AT1-receptor blockade.

  15. Stabilization of the angiotensin-(1-7) receptor Mas through interaction with PSD95.

    Science.gov (United States)

    Bian, Weihua; Sun, Licui; Yang, Longyan; Li, Ji-Feng; Hu, Jia; Zheng, Shuai; Guo, Ruihan; Feng, Duiping; Ma, Qian; Shi, Xiaocui; Xiong, Ying; Yang, Xiaomei; Song, Ran; Xu, Jianguo; Wang, Songlin; He, Junqi

    2013-08-01

    The functions and signalling mechanisms of the Ang-(1-7) [angiotensin-(1-7)] receptor Mas have been studied extensively. However, less attention has been paid to the intracellular regulation of Mas protein. In the present study, PSD95 (postsynaptic density 95), a novel binding protein of Mas receptor, was identified, and their association was characterized further. Mas specifically interacts with PDZ1-2, but not the PDZ3, domain of PSD95 via Mas-CT (Mas C-terminus), and the last four amino acids [ETVV (Glu-Thr-Val-Val)] of Mas-CT were determined to be essential for this interaction, as shown by GST pull-down, co-immunoprecipitation and confocal co-localization experiments. Gain-of-function and loss-of-function studies indicated that PSD95 enhanced Mas protein expression by increasing the stabilization of the receptor. Mas degradation was robustly inhibited by the proteasome inhibitor MG132 in time- and dose-dependent manners, and the expression of PSD95 impaired Mas ubiquitination, indicating that the PSD95-Mas association inhibits Mas receptor degradation via the ubiquitin-proteasome proteolytic pathway. These findings reveal a novel mechanism of Mas receptor regulation by which its expression is modulated at the post-translational level by ubiquitination, and clarify the role of PSD95, which binds directly to Mas, blocking the ubiquitination and subsequent degradation of the receptor via the ubiquitin-proteasome proteolytic pathway.

  16. Renal dopamine and angiotensin II receptor signaling in age-related hypertension.

    Science.gov (United States)

    Chugh, Gaurav; Pokkunuri, Indira; Asghar, Mohammad

    2013-01-01

    Kidneys play a vital role in long-term regulation of blood pressure. This is achieved by actions of many renal and nonrenal factors acting on the kidney that help maintain the body's water and electrolyte balance and thus control blood pressure. Several endogenously formed or circulating hormones/peptides, by acting within the kidney, regulate fluid and water homeostasis and blood pressure. Dopamine and angiotensin II are the two key renal factors that, via acting on their receptors and counterregulating each other's function, maintain water and sodium balance. In this review, we provide recent advances in the signaling cascades of these renal receptors, especially at the level of their cross talk, and discuss their roles in blood pressure regulation in the aging process.

  17. Attenuation of myocardial fibrosis with curcumin is mediated by modulating expression of angiotensin II AT1/AT2 receptors and ACE2 in rats

    Directory of Open Access Journals (Sweden)

    Pang XF

    2015-11-01

    Full Text Available Xue-Fen Pang,1 Li-Hui Zhang,2 Feng Bai,1 Ning-Ping Wang,3 Ron E Garner,3 Robert J McKallip,4 Zhi-Qing Zhao1,3 1Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China; 2Department of Cardiology, Shanxi Academy of Medical Sciences and Shanxi Dayi Hospital, Shanxi Medical University, Taiyuan, Shanxi, People’s Republic of China; 3Department of Basic Biomedical Sciences, Mercer University School of Medicine, Savannah, GA, USA; 4Division of Basic Biomedical Sciences, Mercer University School of Medicine, Macon, GA, USA Abstract: Curcumin is known to improve cardiac function by balancing degradation and synthesis of collagens after myocardial infarction. This study tested the hypothesis that inhibition of myocardial fibrosis by curcumin is associated with modulating expression of angiotensin II (Ang II receptors and angiotensin-converting enzyme 2 (ACE2. Male Sprague Dawley rats were subjected to Ang II infusion (500 ng/kg/min using osmotic minipumps for 2 and 4 weeks, respectively, and curcumin (150 mg/kg/day was fed by gastric gavage during Ang II infusion. Compared to the animals with Ang II infusion, curcumin significantly decreased the mean arterial blood pressure during the course of the observation. The protein level of the Ang II type 1 (AT1 receptor was reduced, and the Ang II type 2 (AT2 receptor was up-regulated, evidenced by an increased ratio of the AT2 receptor over the AT1 receptor in the curcumin group (1.2±0.02% vs in the Ang II group (0.7±0.03%, P<0.05. These changes were coincident with less locally expressed AT1 receptor and enhanced AT2 receptor in the intracardiac vessels and intermyocardium. Along with these modulations, curcumin significantly decreased the populations of macrophages and alpha smooth muscle actin-expressing myofibroblasts, which were accompanied by reduced expression of transforming growth factor beta 1 and phosphorylated-Smad2/3. Collagen I synthesis was

  18. Glucocorticoid-Induced Fetal Programming Alters the Functional Complement of Angiotensin Receptors Subtypes within the Kidney

    Science.gov (United States)

    Gwathmey, TanYa M.; Shaltout, Hossam A.; Rose, James C.; Diz, Debra I.; Chappell, Mark C.

    2011-01-01

    We examined the impact of fetal programming on the functional responses of renal angiotensin receptors. Fetal sheep were exposed in utero to betamethasone (BMX; 0.17 mg/kg) or control (CON) at 80–81 days gestation with full term delivery. Renal nuclear and plasma membrane fractions were isolated from 1.0–1.5 year old sheep for receptor binding and fluorescence detection of reactive oxygen species (ROS) or nitric oxide (NO). Mean arterial blood pressure and blood pressure variability were significantly higher in the BMX-exposed adult offspring versus control (CON) sheep. The proportion of nuclear AT1 receptors sensitive to losartan (LOS) was 2-fold higher [67 ± 6% vs. 27 ± 9%, p < 0.01] in BMX compared to control. In contrast, the proportion of AT2 sites was only one-third that of controls (BMX: 25 ± 11% vs. CON: 78 ± 4%, p < 0.01) with a similar reduction in sites sensitive to the Ang-(1-7) antagonist D-Ala7-Ang-(1-7) with BMX exposure. Functional studies revealed that Ang II stimulated ROS to a greater extent in BMX than control sheep (16 ± 3% vs. 6 ± 4%; P<0.05); however NO production to Ang II was attenuated in BMX (26 ± 7% vs. 82 ± 14%; P<0.05). BMX-exposure was also associated with a reduction in the Ang-(1-7) NO response [75 ± 8% vs. 131 ± 26%; P<0.05]. We conclude that altered expression of angiotensin receptor subtypes may be one mechanism whereby functional changes in NO- and ROS-dependent signaling pathways may favor the sustained increase in blood pressure evident in fetal programming. PMID:21220702

  19. Platelet-derived growth factor receptor-β in myocyte was upregulated by angiotensin II

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    To observe the regulation of platelet-derived growth factor (PDGF) receptor-βin myocyte stimulated by angiotensin II (AngII) at both integrated and cellular levels and reveal the signal transduction mechanism in cell, two kidneys, one clip (2K1C) renal hypertension were performed by placing a sliver clip around the left renal artery. Blood pressure and the ratio of left ventricular weight to body weight were measured at 4 and 8 weeks after operation. The content of AngII in heart was detected by radioimmunology assay; the protein level of PDGF receptor-βin heart was measured by Western blot analysis. The alteration of PDGF receptor-βstimulated by AngII and several inhibitors was observed on cultured neonatal rat ventricular myocyte (NRVM). The content of AngII in heart of 2K1C renal hypertensive rat at 4 and 8 weeks after operation was increased. Compared with sham group, 4 and 8 weeks after operation, PDGF receptor-βin heart of 2K1C group was upregulated by 100.3% and 127.1% (P < 0.05), respectively. This upregulation could be inhibited by captopril. For cultured myocyte, PDGF receptor-βwas increased by 47.1% after being stimulated by AngII and this upregulation could be inhibited by losartan which was an inhibitor of AT1 receptor. PLC inhibitor (U73122) and MEK inhibitor (PD98059) could partly inhibit PDGF receptor-βupregulation induced by AngII. These results suggested that AngII could upregulate PDGF receptor-βin myocyte by its AT1 receptor and this effect was at least partly dependent on PLC and extracellular signal-regulated kinase (ERK).

  20. Angiotensin II receptor blocker telmisartan enhances running endurance of skeletal muscle through activation of the PPAR-δ/AMPK pathway

    Science.gov (United States)

    Feng, Xiaoli; Luo, Zhidan; Ma, Liqun; Ma, Shuangtao; Yang, Dachun; Zhao, Zhigang; Yan, Zhencheng; He, Hongbo; Cao, Tingbing; Liu, Daoyan; Zhu, Zhiming

    2011-01-01

    Abstract Clinical trials have shown that angiotensin II receptor blockers reduce the new onset of diabetes in hypertensives; however, the underlying mechanisms remain unknown. We investigated the effects of telmisartan on peroxisome proliferator activated receptor γ (PPAR-δ) and the adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway in cultured myotubes, as well as on the running endurance of wild-type and PPAR-δ-deficient mice. Administration of telmisartan up-regulated levels of PPAR-δ and phospho-AMPKα in cultured myotubes. However, PPAR-δ gene deficiency completely abolished the telmisartan effect on phospho-AMPKαin vitro. Chronic administration of telmisartan remarkably prevented weight gain, enhanced running endurance and post-exercise oxygen consumption, and increased slow-twitch skeletal muscle fibres in wild-type mice, but these effects were absent in PPAR-δ-deficient mice. The mechanism is involved in PPAR-δ-mediated stimulation of the AMPK pathway. Compared to the control mice, phospho-AMPKα level in skeletal muscle was up-regulated in mice treated with telmisartan. In contrast, phospho-AMPKα expression in skeletal muscle was unchanged in PPAR-δ-deficient mice treated with telmisartan. These findings highlight the ability of telmisartan to improve skeletal muscle function, and they implicate PPAR-δ as a potential therapeutic target for the prevention of type 2 diabetes. PMID:20477906

  1. Bone marrow angiotensin AT2 receptor deficiency aggravates atherosclerosis development by eliminating macrophage liver X receptor-mediated anti-atherogenic actions.

    Science.gov (United States)

    Kato, Taku; Kawahito, Hiroyuki; Kishida, Sou; Irie, Daisuke; Wakana, Noriyuki; Kikai, Masakazu; Takata, Hiroki; Ogata, Takehiro; Ueyama, Tomomi; Matoba, Satoaki; Yamada, Hiroyuki

    2015-12-01

    Bone marrow (BM) Angiotensin II (Ang II) type 1 (AT1) receptor plays a crucial role in atherosclerosis development; however, the effect of BM Ang II type 2 (AT2) receptor on atherogenesis remains undefined. We generated BM chimera apoE-deficient (apoE(-/-)) mice whose BM cells were repopulated with AT2-deficient (Agtr2(-/-)) or wild-type (Agtr2(+/+)) cells. After 2 months of a high-cholesterol diet, the atherosclerotic lesion area was significantly increased in the apoE(-/-)/BM-Agtr2(-/-) mice compared with the apoE(-/-)/BM-Agtr2(+/+) mice (51%, P < 0.05), accompanied by an augmented accumulation of lesion macrophages. Although phenotypic polarization in BM-derived macrophages and lipopolysaccharide-induced expression of proinflammatory cytokines in thioglycollate-induced peritoneal macrophages (TGPMs) were not affected by AT2-deficiency, mRNA and protein expression levels of macrophage liver X receptor β (LXRβ) were significantly decreased in Agtr2(-/-) TGPMs compared with Agtr2(+/+) TGPMs. Anti-inflammatory effects of LXR agonist (GW3965) were markedly inhibited in Agtr2(-/-) TGPMs. Furthermore, the expression levels of ATP-binding cassette transporter ABCA1 and CCR7 were much lower in Agtr2(-/-) TGPMs than Agtr2(+/+) TGPMs, accompanied by a significantly reduced cholesterol efflux. Our findings demonstrate that BM-AT2 deficiency aggravates atherosclerosis, at least in part, by eliminating the anti-atherogenic properties of macrophages elicited by LXRβ activation. © The Author(s) 2014.

  2. Design of angiotensin II derivatives suitable for indirect affinity techniques: potential applications to receptor studies.

    Science.gov (United States)

    Bonnafous, J C; Seyer, R; Tence, M; Marie, J; Kabbaj, M; Aumelas, A

    1988-01-01

    The design of angiotensin II (A II)-derived probes suitable for indirect affinity techniques is presented. Biotin or dinitrophenyl moieties have been added at the N-terminus of A II, through aminohexanoic acid as spacer arm, to generate (6-biotinylamido)-hexanoyl-AII (Bio-Ahx-AII) and dinitrophenyl- aminohexanoyl-AII (Dnp-Ahx-AII). Monoiodinated and highly labeled radioiodinated forms of these probes have been prepared. The two bifunctional ligands displayed high affinities for rat liver A II receptors (Kd values in the nanomolar range) and their secondary acceptors: streptavidin and monoclonal anti-Dnp antibodies respectively. Bio-Ahx-AII and Dnp-Ahx-AII behaved as agonists on several AII-sensitive systems. Based on these structural assessments, the parent photoactivable azido probe: Bio-Ahx-(Ala1,Phe(4N3)8)A II. A II was synthesized and proved to possess similar biological properties than the non-azido compound. The hepatic A II receptor could be covalently labeled by the radioiodinated probe, with a particularly high yield (15-20%); SDS-polyacrylamide gel electrophoresis of solubilized complexes revealed specific labeling of a 65 Kdaltons binding unit, in agreement with previous data obtained with other azido AII-derived compounds. The potential applications of these probes are: i) receptor purification by combination of its photoaffinity labeling and adsorption of biotin-tagged solubilized hormone-receptor complexes on avidin gels. ii) cell labeling and sorting. iii) histochemical receptor visualization.

  3. Angiotensin II, sympathetic nerve activity and chronic heart failure.

    Science.gov (United States)

    Wang, Yutang; Seto, Sai-Wang; Golledge, Jonathan

    2014-03-01

    Sympathetic nerve activity has been reported to be increased in both humans and animals with chronic heart failure. One of the mechanisms believed to be responsible for this phenomenon is increased systemic and cerebral angiotensin II signaling. Plasma angiotensin II is increased in humans and animals with chronic heart failure. The increase in angiotensin II signaling enhances sympathetic nerve activity through actions on both central and peripheral sites during chronic heart failure. Angiotensin II signaling is enhanced in different brain sites such as the paraventricular nucleus, the rostral ventrolateral medulla and the area postrema. Blocking angiotensin II type 1 receptors decreases sympathetic nerve activity and cardiac sympathetic afferent reflex when therapy is administered to the paraventricular nucleus. Injection of an angiotensin receptor blocker into the area postrema activates the sympathoinhibitory baroreflex. In peripheral regions, angiotensin II elevates both norepinephrine release and synthesis and inhibits norepinephrine uptake at nerve endings, which may contribute to the increase in sympathetic nerve activity seen in chronic heart failure. Increased circulating angiotensin II during chronic heart failure may enhance the sympathoexcitatory chemoreflex and inhibit the sympathoinhibitory baroreflex. In addition, increased circulating angiotensin II can directly act on the central nervous system via the subfornical organ and the area postrema to increase sympathetic outflow. Inhibition of angiotensin II formation and its type 1 receptor has been shown to have beneficial effects in chronic heart failure patients.

  4. Genomic association analysis identifies multiple loci influencing antihypertensive response to an angiotensin II receptor blocker.

    Science.gov (United States)

    Turner, Stephen T; Bailey, Kent R; Schwartz, Gary L; Chapman, Arlene B; Chai, High Seng; Boerwinkle, Eric

    2012-06-01

    To identify genes influencing blood pressure response to an angiotensin II receptor blocker, single nucleotide polymorphisms identified by genome-wide association analysis of the response to candesartan were validated by opposite direction associations with the response to a thiazide diuretic, hydrochlorothiazide. We sampled 198 white and 193 blacks with primary hypertension from opposite tertiles of the race-sex-specific distributions of age-adjusted diastolic blood pressure response to candesartan. There were 285 polymorphisms associated with the response to candesartan at P<10(-4) in whites. A total of 273 of the 285 polymorphisms, which were available for analysis in a separate sample of 196 whites, validated for opposite direction associations with the response to hydrochlorothiazide (Fisher χ(2) 1-sided P=0.02). Among the 273 polymorphisms, those in the chromosome 11q21 region were the most significantly associated with response to candesartan in whites (eg, rs11020821 near FUT4, P=8.98 × 10(-7)), had the strongest opposite direction associations with response to hydrochlorothiazide (eg, rs3758785 in GPR83, P=7.10 × 10(-3)), and had the same direction associations with response to candesartan in the 193 blacks (eg, rs16924603 near FUT4, P=1.52 × 10(-2)). Also notable among the 273 polymorphisms was rs11649420 on chromosome 16 in the amiloride-sensitive sodium channel subunit SCNN1G involved in mediating renal sodium reabsorption and maintaining blood pressure when the renin-angiotensin system is inhibited by candesartan. These results support the use of genomewide association analyses to identify novel genes predictive of opposite direction associations with blood pressure responses to inhibitors of the renin-angiotensin and renal sodium transport systems.

  5. Heterogeneous Downregulation of Angiotensin II AT1-A and AT1-B Receptors in Arterioles in STZ-Induced Diabetic Rat Kidneys

    Directory of Open Access Journals (Sweden)

    Zsolt Razga

    2014-01-01

    Full Text Available Introduction. The renin granulation of kidney arterioles is enhanced in diabetes despite the fact that the level of angiotensin II in the diabetic kidney is elevated. Therefore, the number of angiotensin II AT1-A and AT1-B receptors in afferent and efferent arteriole’s renin-positive and renin-negative smooth muscle cells (SMC was estimated. Method. Immunohistochemistry at the electron microscopic level was combined with 3D stereological sampling techniques. Results. In diabetes the enhanced downregulation of AT1-B receptors in the renin-positive than in the renin-negative SMCs in both arterioles was resulted: the significant difference in the number of AT1 (AT1-A + AT1-B receptors between the two types of SMCs in the normal rats was further increased in diabetes and in contrast with the significant difference observed between the afferent and efferent arterioles in the normal animals, there was no such difference in diabetes. Conclusions. The enhanced downregulation of the AT1-B receptors in the renin-negative SMCs in the efferent arterioles demonstrates that the regulation of the glomerular filtration rate by the pre- and postglomerular arterioles is changed in diabetes. The enhanced downregulation of the AT1-B receptors in the renin-positive SMCs in the arterioles may result in an enhanced level of renin granulation in the arterioles.

  6. Angiotensin AT1 and AT2 receptor antagonists modulate nicotine-evoked [³H]dopamine and [³H]norepinephrine release.

    Science.gov (United States)

    Narayanaswami, Vidya; Somkuwar, Sucharita S; Horton, David B; Cassis, Lisa A; Dwoskin, Linda P

    2013-09-01

    Tobacco smoking is the leading preventable cause of death in the United States. A major negative health consequence of chronic smoking is hypertension. Untoward addictive and cardiovascular sequelae associated with chronic smoking are mediated by nicotine-induced activation of nicotinic receptors (nAChRs) within striatal dopaminergic and hypothalamic noradrenergic systems. Hypertension involves both brain and peripheral angiotensin systems. Activation of angiotensin type-1 receptors (AT1) release dopamine and norepinephrine. The current study determined the role of AT1 and angiotensin type-2 (AT2) receptors in mediating nicotine-evoked dopamine and norepinephrine release from striatal and hypothalamic slices, respectively. The potential involvement of nAChRs in mediating effects of AT1 antagonist losartan and AT2 antagonist, 1-[[4-(dimethylamino)-3-methylphenyl]methyl]-5-(diphenylacetyl)-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid (PD123319) was evaluated by determining their affinities for α4β2* and α7* nAChRs using [³H]nicotine and [³H]methyllycaconitine binding assays, respectively. Results show that losartan concentration-dependently inhibited nicotine-evoked [³H]dopamine and [³H]norepinephrine release (IC₅₀: 3.9 ± 1.2 and 2.2 ± 0.7 μM; Imax: 82 ± 3 and 89 ± 6%, respectively). In contrast, PD123319 did not alter nicotine-evoked norepinephrine release, and potentiated nicotine-evoked dopamine release. These results indicate that AT1 receptors modulate nicotine-evoked striatal dopamine and hypothalamic norepinephrine release. Furthermore, AT1 receptor activation appears to be counteracted by AT2 receptor activation in striatum. Losartan and PD123319 did not inhibit [³H]nicotine or [³H]methyllycaconitine binding, indicating that these AT1 and AT2 antagonists do not interact with the agonist recognition sites on α4β2* and α7* nAChRs to mediate these effects of nicotine. Thus, angiotensin receptors contribute to the effects of

  7. Individualized prediction of the effect of angiotensin receptor inhibition on renal and cardiovascular outcomes in patients with diabetic nephropathy

    NARCIS (Netherlands)

    van der Sande, Nicolette G C; Dorresteijn, Jannick A N; Visseren, Frank L J; Dwyer, Jamie P; Blankestijn, Peter J; van der Graaf, Yolanda; Heerspink, Hiddo L

    2016-01-01

    Aims Angiotensin receptor blockers (ARBs) reduce cardiovascular and renal complications in patients with diabetic nephropathy but treatment effects may vary across patients. Predicting individualized treatment effect of ARBs on both outcomes may help clinicians and patients to assess the benefit of

  8. Individualized prediction of the effect of angiotensin receptor inhibition on renal and cardiovascular outcomes in patients with diabetic nephropathy

    NARCIS (Netherlands