Vascular stiffness as a cause of resistant hypertension (HAR) in obese patients: role of aldosterone and resistin

• Grant number: 11/10936-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2011
• End date: December 31, 2011
• Field of knowledge: Biological Sciences - Pharmacology - Cardiorenal Pharmacology
• Principal Investigator: Heitor Moreno Junior
• Grantee: Andressa Nunes
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The Resistant Hypertension (RH) is characterized as the presence of hypertension and concomitant use of three different classes of antihypertensive drugs with at least one of these agents been a diuretic. In 2008, the American Heart Association (AHA) added to this hypertensive group those patients who require four or more classes of antihypertensive drugs to achieve blood pressure control. Currently, it has been largely discussed the influence of obesity both in hypertension and in resistance to antihypertensive therapy, controversy over the fact whether high levels of aldosterone are responsible for the vascular stiffness that perpetuates the lack of blood pressure control in these patients. Hormones secreted by adipose tissue, such as resistin, may have effects regardless of obesity on blood pressure control. For example, the increase in resistin in obesity is associated with insulin resistance, inflammation, atherogenesis and therefore may also be responsible for changes in the cardiovascular system such as the stiffness of large and medium caliber arterial walls. This arterial elasticity loss may be related to absence or poor blood pressure response to antihypertensive therapy and renal and cardiac lesions, such as left ventricular hypertrophy (LVH) and microalbuminuria. This project aims to determine the role of aldosterona and resistin on vascular stiffness in obese and nonobese resistant hypertensive patients. Also, target organ damage markers (LVH and microalbuminuria) will be secondarily analyzed. In this study will be included 60 resistant hypertensive patients diagnosed with resistant hypertension with proven adherence to pharmacological and non pharmacological action from the Ambulatory of Resistant Hypertension HC-FCM/UNICAMP. They will be divided in two groups: 1- uncontrolled resistant hypertensives (UC-RHTN, n = 30), which will be divided in two subgroups, without obesity ((NO)UC-RHTN, n = 15) and obesity ((O)UC-RHTN, n = 15); 2- controlled resistant hypertensives (C-RHTN, n = 30), which will be divided in two subgroups, without obesity ((NO)C-RHTN, n = 15) and obesity ((O)C-RHTN, n = 15). The arterial stiffness related parameters will be obtained by analyzing the pulse wave velocity in the radial artery by applanation tonometry system. The resistin and aldosterone plasma concentrations will be determined by enzyme linked immunosorbent assay (ELISA). The association evaluation between plasma levels of resistin and the different degrees of vascular stiffness contribute to a better understanding of blood pressure low responsiveness pathophysiology in obese hypertensives.