Pathophysiology of Arterial Hypertension: Insights from Pediatric Studies
Ana Cristina Simoes e Silva.
Blood pressure is the direct product of cardiac output and total peripheral resistance. Cardiac output is regulated by preload, myocardium contractility and heart rate, while total peripheral resistance depends on afterload and vessel elasticity. The maintenance of blood pressure within normal limits is influenced by neural, humoral and local control mechanisms, which have extensive and complex interactions, making difficult an individual analysis. Thus, isolated or combined disarrangements in these mechanisms can lead to the development of hypertension. Neural blood pressure regulation mainly depends on lower brain stem centers of cardiovascular control and the autonomous nervous system, integrating the cardiovascular reflexes. In regard to humoral mechanisms, several substances/ systems contribute for increasing blood pressure (Angiotensin II, circulating cathecolamines), while others can play a counterregulatory role [Angiotensin-(1-7), kallikrein-kinin system and natriuretic peptides]. Moreover, local factors, such as nitric oxide and endothelins, act as determinants of vascular resistance and as systemic or local modifiers of neural and humoral mechanisms. Recently, research has begun to disclose the mechanisms related to blood pressure regulation at cellular and molecular level. In this review, we discussed experimental and clinical evidence relating to regulatory mechanisms probably involved in the pathophysiology of arterial hypertension with insights from pediatric studies.
Keywords: Pediatric hypertension, sympathetic nervous system, Renin Angiotensin System, kallikrein-kinin system, natriuretic peptides, endothelial factors
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