Weight Loss and the Renin-Angiotensin-Aldosterone System

TLDR

The renin‑angiotensin‑aldosterone system has been causally implicated in obesity‑associated hypertension. This study examined how obesity and weight loss affect circulating and adipose‑tissue RAAS activity in menopausal women. Blood and adipose‑tissue biopsies were assayed for angiotensinogen, renin, aldosterone, ACE activity, and receptor expression, and a 13‑week 600‑kcal/day caloric‑restriction program was used to evaluate changes. Obese women had higher circulating RAAS components and lower adipose angiotensinogen expression, and a 5 % weight loss reduced these markers and systolic blood pressure, suggesting that modest weight loss attenuates the RAAS and may lower hypertension risk.

Abstract

The renin-angiotensin-aldosterone system has been causally implicated in obesity-associated hypertension. We studied the influence of obesity and weight reduction on the circulating and adipose tissue renin-angiotensin-aldosterone system in menopausal women. Blood samples were analyzed for angiotensinogen, renin, aldosterone, angiotensin-converting enzyme activity, and angiotensin II. In adipose tissue biopsy samples, we analyzed angiotensinogen, renin, renin-receptor, angiotensin-converting enzyme, and angiotensin II type-1 receptor gene expression. Obese women (n=19) had higher circulating angiotensinogen, renin, aldosterone, and angiotensin-converting enzyme than lean women (n=19), and lower angiotensinogen gene expression in adipose tissue. Seventeen women successfully participated in a weight reduction protocol over 13 weeks to reduce daily caloric intake by 600 kcal. Body weight was reduced by -5%, as were angiotensinogen levels by -27%, renin by -43%, aldosterone by -31%, angiotensin-converting enzyme activity by -12%, and angiotensinogen expression by -20% in adipose tissue (all P<0.05). The plasma angiotensinogen decrease was highly correlated with the waist circumference decline (r=0.74; P<0.001). Weight and renin-angiotensin-aldosterone system reductions were accompanied by a -7-mm Hg reduced systolic ambulatory blood pressure. These data suggest that a 5% reduction in body weight can lead to a meaningfully reduced renin-angiotensin-aldosterone system in plasma and adipose tissue, which may contribute to the reduced blood pressure.