Weight loss and the renin-angiotensin-aldosterone system

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.