Abstract

Introduction Visceral obesity, a feature of the metabolic syndrome, is associated with metabolic and cardiovascular diseases. Our aim was to study the influence of increased fat intake, a major determinant of central obesity, on Smooth Muscle Cells (SMC) reactivity and its interaction with Perivascular Adipose Tissue (PVAT), which plays an important role in the local regulation of vascular function, with a special emphasis on oxidative stress. Methods From weaning, rats were fed low-fat or High-Fat Diet (HFD) for 5 months. The implication of oxidative stress mediated by PVAT and/or SMC on vascular function was investigated in isolated endothelium-removed aortic rings. Results HFD increased PVAT mass and thiobarbituric acid reactive substances concentrations. Although HFD did not change phenylephrine-induced contraction and PVAT anticontractile activity, the HFD-induced central obesity was associated with increased aortic wall procontractile activity generated by NADPH oxidase. Such phenomenon was counteracted by increased aortic wall dismutation activity and decreased PVAT procontractile activity. Conclusions The apparent lack of change of vascular reactivity in HFD-fed rats was subsequent to a new equilibrium state between vascular wall and PVAT oxidative stress-induced procontractile and prorelaxant activities. This observation predicts that any defect in the above-mentioned counterregulatory mechanisms can have deleterious functional consequences.

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