Telmisartan acts through the modulation of ACE-2/ANG 1-7/mas receptor in rats with dilated cardiomyopathy induced by experimental autoimmune myocarditis
ABSTRACT Recent findings have suggested that a therapeutic approach to amplify or stimulate the angiotensin-converting enzyme-2 [ACE-2]-angiotensin 1-7 [ANG 1-7] mas axis could provide protection against the development of cardiovascular diseases. We investigated the cardioprotective effects of telmisartan in rats with dilated cardiomyopathy [DCM] after experimental autoimmune myocarditis [EAM].
DCM was elicited in Lewis rats by immunization with cardiac myosin, and twenty-eight days after immunization, the surviving Lewis rats were divided into two groups and treated with either telmisartan (10mg/kg/day) or vehicle.
Telmisartan treatment effectively suppressed myocardial protein and mRNA expressions of inflammatory markers [CD68, iNOS, NF-kB, interleukin-1β, interferon-γ, monocyte chemotactic protein-1] in comparison to vehicle-treated rats. In contrast, myocardial protein levels of ACE-2 and ANG 1-7 mas receptor were upregulated in the telmisartan-treated group compared with vehicle-treated rats. Telmisartan treatment significantly reduced fibrosis and hypertrophy and their marker molecules [OPN, CTGF, TGF-β1 and collagens I and III and atrial natriuretic peptide and GATA-4, respectively] compared with those of vehicle-treated rats. In addition, telmisartan treatment significantly lowered the protein expressions of NADPH oxidase subunits p47phox, p67phox, and superoxide production when compared with vehicle-treated rats. Telmisartan treatment significantly decreased the expression levels of mitogen-activated protein kinase (MAPK) signaling molecules than with those of vehicle-treated rats. Also, telmisartan treatment significantly improved LV systolic and diastolic function.
These results indicate that telmisartan treatment significantly improved LV function and ameliorated the progression of cardiac remodeling through the modulation of ACE-2/ANG 1-7/Mas receptor axis in rats with DCM after EAM.
- SourceAvailable from: Ana Cristina Simões e Silva[Show abstract] [Hide abstract]
ABSTRACT: Recent advances have improved our understanding of the Renin-Angiotensin System (RAS). These have included the recognition that Angiotensin (Ang)-(1-7) is a biologically active product of the RAS cascade. The identification of the angiotensin-converting enzyme (ACE) homolog ACE2, which forms Ang-(1-7) from Ang II, and the G-protein-coupled receptor Mas as an Ang-(1-7) receptor have provided the necessary biochemical and molecular background and tools to study the biological significance of Ang-(1-7). Most available evidence supports a counter-regulatory role for Ang-(1-7) by opposing many actions of Ang II on AT1 receptors, especially vasoconstriction and proliferation. Many studies have now shown that Ang-(1-7) by acting via Mas receptor exerts inhibitory effects on inflammation and on vascular and cellular growth mechanisms. Ang-(1-7) has also been shown to reduce key signaling pathways and molecules thought to be relevant for fibrogenesis. Here, we review recent findings related to the function of the ACE2/Ang-(1-7)/Mas axis and focus on the role of this axis in modifying processes associated with acute and chronic inflammation, including leukocyte influx, fibrogenesis and proliferation of certain cell types. More attention will be given to the involvement of the ACE2/Ang-(1-7)/Mas axis in the context of renal disease, because of the known relevance of the RAS for the function of this organ and for the regulation of kidney inflammation and fibrosis. Taken together, this knowledge may help in paving the way for the development of novel treatments for chronic inflammatory and renal diseases.British Journal of Pharmacology 03/2013; 169(3). DOI:10.1111/bph.12159 · 4.99 Impact Factor
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ABSTRACT: The use of multiple drug regimens is increasingly recognized as a tacit requirement for the management of hypertension, a necessity fueled in part by rising rates of metabolic syndrome and diabetes. By targeting complementary pathways, combinations of antihypertensive drugs can be applied to provide effective blood pressure control while minimizing side effects and reducing exposure to high doses of individual medications. In addition, combination therapies, including angiotensin converting enzyme (ACE) inhibitors and calcium channel blockers (CCBs), have the added benefit of reducing cardiovascular mortality and morbidity over other dual therapies while providing equivalent blood pressure control. It is possible that angiotensin receptor blockers (ARBs), which unlike ACE inhibitors are minimally affected by upregulation of alternative pathways for angiotensin II accumulation following long-term treatment, would also provide such outcome benefits. At issue, however, is maintaining patient compliance, as adding medications is known to reduce adherence to treatment regimens. The purpose of this review is to summarize existing trial data for the long-term safety and efficacy of a recent addition to the armamentarium of dual-antihypertensive therapeutic options, the telmisartan/amlodipine single pill combination. The areas where long-term data are lacking, notably clinical information regarding minorities and women, will also be discussed.Vascular Health and Risk Management 03/2013; 9:95-104. DOI:10.2147/VHRM.S40963
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ABSTRACT: Angiotensin (Ang) II and its AT1 receptors have been implicated in the pathogenesis of Rheumatoid Arthritis. Activation of the counter-regulatory Ang-(1-7)-Mas receptor axis may contribute to some of the effects of AT1 receptor blockers (ARBs). In this study, we have used losartan, an ARB, to investigate the role of and the mechanisms by which AT1 receptors participated in two experimental models of arthritis: antigen-induced arthritis (AIA) in mice and adjuvant-induced arthritis (AdIA) in rats. Treatment with losartan decreased neutrophil recruitment, hypernociception and the production of TNF-α, IL-1β and chemokine (C-X-C motif) ligand 1 in mice subjected to AIA. Histopathological analysis showed significant reduction of tissue injury and inflammation and decreased proteoglycan loss. In addition to decreasing cytokine production, losartan directly reduced leukocyte rolling and adhesion. Anti-inflammatory effects of losartan were not associated to Mas receptor activation and/or Ang-(1-7) production. Anti-inflammatory effects were reproduced in rats subjected to AdIA. This study shows that ARBs have potent anti-inflammatory effects in animal models of arthritis. Mechanistically, reduction of leukocyte accumulation and of joint damage was associated with local inhibition of cytokine production and direct inhibition of leukocyte-endothelium interactions. The anti-inflammatory actions of losartan were accompanied by functional improvement of the joint, as seen by reduced joint hypernociception. These findings support the use of ARBs for the treatment of human arthritis and provide potential mechanisms for the anti-inflammatory actions of these compounds.Peptides 05/2013; 46. DOI:10.1016/j.peptides.2013.05.012 · 2.61 Impact Factor