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Myocardial infarction triggers cellular events that starts with the activation of inflammatory response and fibrogenic pathways involved in cardiac tissue remodeling. Angiotensin-(1-7) (Ang-(1-7)) is an endogenous heptapeptide from the renin-angiotensin system with a cardioprotective role due to its anti-inflammatory and anti-fibrotic activities in cardiac cells. Although the beneficial aspects of Ang-(1-7) in animal models of cardiac ischemia have been reported, the molecular events underlying Ang-(1-7) cardioprotective effect remains elusive. This study investigated the impact of oral treatment with Ang-(1-7) included in hydroxypropyl β-cyclodextrin (HPβCD/Ang-(1-7)) on the cardiac proteome dysregulation due to experimental myocardial infarction. Wistar male rats were submitted to experimental myocardial infarction and treated daily with HPβCD/Ang-(1-7) during 7 days or 60 days by gavage. Our results showed that HPβCD/Ang-(1-7) treatment ameliorates the post-infarction condition due to the modulation of proteins that initially favor the resolution of inflammation and mitochondrial dysfunction. Moreover, this study reported for the first time that Ang-(1-7) treatment after experimental myocardial infarction leads to the downregulation of the C-X-C chemokine receptor type 4 (CXCR4). SIGNIFICANCE: Myocardial infarction triggers a sequence of cellular and molecular events that starts with an intense inflammatory response that is resolved in the proliferative phase. Prolonged inflammatory phase can lead to adverse cardiac repair and heart failure. In this context, we proposed a post-MI treatment using Ang-(1-7) included in HPβCD and administrated orally. We observed that HPβCD/Ang-(1-7) treatment led to CXCR4 downregulation, highlighting this C-X-C chemokine receptor as a potential therapeutic target for ischemic heart diseases., (Copyright © 2019 Elsevier B.V. All rights reserved.)

CGEN-856S is a novel Mas agonist. Herein, we examined the effects of this peptide on isoproterenol (ISO)-induced cardiac remodeling and myocardial infarction (MI) injury. We also sought to determine whether CGEN-856S activates the underlying mechanisms related to Mas receptor activation. Heart hypertrophy and fibrosis were induced by ISO (2 mg·kg(-1)·day(-1)) in Wistar rats. After a 7-day treatment period with CGEN-856S (90 µg·kg(-1)·day(-1)) or vehicle, the cardiomyocyte diameter was evaluated in left ventricular sections stained with hematoxylin and eosin, and immunofluorescence labeling and quantitative confocal microscopy were used to quantify the deposition of type I and III collagen and fibronectin in the left ventricles. MI was induced by coronary artery ligation, and CGEN-856S (90 µg·kg(-1)·day(-1)) or saline was administered for 14 days. The Langendorff technique was used to evaluate cardiac function, and left ventricular sections were stained with Masson's trichrome dye to quantify the infarct area. Using Chinese hamster ovary cells stably transfected with Mas cDNA, we evaluated whether CGEN-856S alters AKT and endothelial nitric oxide synthase (eNOS) phosphorylation. CGEN-856S reduced the degree of ISO-induced hypertrophy (13.91±0.17 µm vs. 12.41±0.16 µm in the ISO+CGEN-856S group). In addition, the Mas agonist attenuated the ISO-induced increase in collagen I, collagen III, and fibronectin deposition. CGEN-856S markedly attenuated the MI-induced decrease in systolic tension, as well as in +dT/dt and -dT/dt. Furthermore, CGEN-856S administration significantly decreased the infarct area (23.68±2.78% vs. 13.95±4.37% in the MI+CGEN-856S group). These effects likely involved the participation of AKT and NO, as CGEN-856S administration increased the levels of p-AKT and p-eNOS. Thus, our results indicate that CGEN-856S exerts cardioprotective effects on ISO-induced cardiac remodeling and MI-mediated heart failure in rats through a mechanism likely involving the eNOS/AKT pathway.

In this study we evaluated the cardiac effects of a pharmaceutical formulation developed by including angiotensin (Ang)-(1-7) in hydroxypropyl β-cyclodextrin (HPβCD), in normal, infarcted, and isoproterenol-treated rats. Myocardial infarction was produced by left coronary artery occlusion. Isoproterenol (2 mg/kg, IP) was administered daily for 7 days. Oral administration of HPβCD/Ang-(1-7) started immediately before infarction or associated with the first dose of isoproterenol. After 7 days of treatment, the rats were euthanized, and the Langendorff technique was used to analyze cardiac function. In addition, heart function was chronically (15, 30, 50 days) analyzed by echocardiography. Cardiac sections were stained with hematoxylin/eosin and Masson trichrome to evaluate cardiac hypertrophy and damage, respectively. Pharmacokinetic studies showed that oral HPβCD/Ang-(1-7) administration significantly increased Ang-(1-7) on plasma whereas with the free peptide it was without effect. Oral administration of HPβCD/Ang-(1-7) (30 μg/kg) significantly reduced the deleterious effects induced by myocardial infarction on systolic and diastolic tension, ±dT/dt, perfusion pressure, and heart rate. Strikingly, a 50% reduction of the infarcted area was observed in HPβCD/Ang-(1-7)-treated rats. Furthermore, HPβCD/Ang-(1-7) attenuated the heart function impairment and cardiac remodeling induced by isoproterenol. In infarcted rats chronically treated with HPβCD/Ang-(1-7), the reduction of ejection fraction and fractional shorting and the increase in systolic and diastolic left ventricular volumes observed in infarcted rats were attenuated. Altogether, these findings further confirm the cardioprotective effects of Ang-(1-7). More importantly, our data indicate that the HPβCD/Ang-(1-7) is a feasible formulation for oral administration of Ang-(1-7), which can be used as a cardioprotective drug.