Alterações cardiovasculares associadas à obesidade induzida por dieta de cafeteria e o papel do tecido adiposo perivascular (PVAT)

Abstract

Obesity is among the most important causes of cardiovascular disease. The perivascular adipose tissue (PVAT) is closely related to the cardiovascular system playing an important role in vascular homeostasis, which may be associated with the progression or regression of cardiovascular diseases related to obesity. Knowing that the cafeteria diet (CAF diet) reflects the variety of highly caloric and easily accessible foods in Western societies, contributing to the development of obesity and metabolic disorders, the aim of this study was to evaluate the impact of CAF diet on the cardiovascular system, as well as its influence on the PVAT vasoactive profile. The results found showed that the CAF diet induced an increase in the body weight and adiposity index, hyperlipidemia, hyperglycemia, glucose intolerance and insulin resistance. The analysis of the electrocardiogram and cardiac function showed that the CAF diet caused a delay in atrioventricular conduction and an increase in baseline left ventricular contractility/relaxation. The same result was observed at the cellular level, in which the CAF diet exacerbated the contraction/relaxation response of cardiomyocytes. However, under a pharmacological stress induced by isoprenaline, left ventricular contractility/relaxation in the CAF group proved to be less responsive. The CAF diet also induced a reduction in vascular contractility induced by phenylephrine (PE) in the absence of PVAT related to the increase in serum leptin levels and the activation of its receptors, activation of PI3K enzymes and nitric oxide endothelial synthase, and production of nitric oxide and hydrogen peroxide. On the other hand, the presence of PVAT increased PE-induced vasoconstriction in the CAF group, suggesting a vasoconstrictor profile of PVAT in an attempt to reestablish the vascular contractility related to the activation of AT1 receptors, activation of NADPH oxidase and production of superoxide anions, and activation of the cyclooxygenase 1 and the thromboxane A2 and prostaglandin F2α receptors. Taken together, our findings showed that obesity triggered by CAF diet predisposes to cardiac and vascular alterations, with alterations in the vasoactive profile of PVAT. However, dietary treatment alternating the CAF diet to the standard diet proved to be effective in reversing these changes.