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.
"In a model of ADR-induced heart failure in Male Sprague-Dawley rats, Zong et al (2011) detected a decrease of plasma Ang-(1–7) levels and reduced myocardial expression of Mas receptor, while the treatment with telmisartan or losartan increased Ang-(1–7) levels and suppressed myocardial AT1 receptor expression without changing the expression of Mas . Recent studies of Sukumaran et al (2011 and 2012) showed that the protein and mRNA levels of Mas receptor, ACE2 and Ang-(1–7) were upregulated in olmesartan treated group in experimental autoimmune myocarditis and these changes in RAS components decreased the expression of inflammatory markers , . Taken together, these findings indicated that ACE2/Ang-(1–7)/Mas receptor axis activation participate in the renoprotection triggered by ARB "
[Show abstract][Hide abstract] ABSTRACT: 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.
PLoS ONE 06/2013; 8(6):e66082. DOI:10.1371/journal.pone.0066082 · 3.23 Impact Factor
[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 · 4.84 Impact Factor
[Show abstract][Hide abstract] 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(1):95-104. DOI:10.2147/VHRM.S40963
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