Role of renin-angiotensin-aldosterone system in adipose tissue dysfunction

The renin-angiotensin-aldosterone system (RAAS) is known to be closely linked to the pathogenesis of insulin resistance. The angiotensin (Ang) II type 1 (AT(1)) receptor mediates the major effects of Ang II in adipose tissue, and blockade of the AT(1) receptor improves insulin sensitivity, with enhanced adipocyte differentiation. In contrast, the role of angiotensin type 2 (AT(2)) receptor activation in insulin sensitivity is still controversial, although AT(2) receptor functions are thought to be mutually antagonistic against those of the AT(1) receptor in the cardiovascular system. Aldosterone exerts its biological roles via the mineral-corticoid receptor (MR), and inhibition of MR signaling in adipose tissue ameliorates inflammation, with upregulation of insulin-mediated glucose transport and adipocyte differentiation. Clinical studies indicate that blockade of RAAS prevents the new onset of type 2 diabetes and improves the metabolic syndrome in diabetic patients. We here review the recent concepts of the roles of RAAS in adipose tissue. (C) 2012 Elsevier Ireland Ltd. All rights reserved.