Title:Potential Effect of Angiotensin II Receptor Blockade in Adipose Tissue and Bone
VOLUME: 19 ISSUE: 17
Author(s):Hironori Nakagami, Mariana Kiomy Osako and Ryuichi Morishita
Affiliation:Division of Vascular Medicine and Epigenetics, Osaka University United Graduate School of Child Development, 2-1 Yamada-oka, Suita 565-0871, Japan.
Keywords:Angiotensin II, adipose tissue, obesity, osteoporosis, osteoclast.
Abstract:Recent evidence demonstrated that dysregulation of adipocytokine functions seen in abdominal obesity may be involved in the
pathogenesis of the metabolic syndrome. Angiotensinogen, the precursor of angiotensin (Ang) II, is produced primarily in the liver, and
also in adipose tissue, where it is up-regulated during the development of obesity and involved in blood pressure regulation and adipose
tissue growth. Blockade of renin-angiotensin system (RAS) attenuates weight gain and adiposity by enhanced energy expenditure, and
the favorable metabolic effects of telmisartan have been related to its Ang II receptor blockade and action as a partial agonist of peroxisome
proliferators activated receptor (PPAR)-γ. PPARγ plays an important role in regulating carbohydrate and lipid metabolism, and
ligands for PPARγ can improve insulin sensitivity and reduce triglyceride levels. Similarly, bone metabolism is closely regulated by
hormones and cytokines, which have effects on both bone resorption and deposition. It is known that the receptors of Ang II are expressed
in culture osteoclasts and osteoblasts, and Ang II is postulated to be able to act upon the cells involved in bone metabolism. In in
vitro system, Ang II induced the differentiation and activation of osteoclasts responsible for bone resorption. Importantly, it was demonstrated
by the sub-analysis of a recent clinical study that the fracture risk was significantly reduced by the usage of angiotensinconverting
enzyme inhibitors. To treat the subgroups of hypertensive patients with osteoporosis RAS can be considered a novel target.
