Effects of PPARγ agonists against vascular and renal dysfunction

Peroxisome proliferator-activated receptor (PPAR)γ, a nuclear hormone receptor, is activated by its agonists including anti-diabetic thiazolidinediones, and has recently been reported to exert beneficial effects in the vasculature independently of its anti-diabetic effects. We here discuss our recent findings on the beneficial pleiotropic effects of PPARγ agonists. PPARγ agonists have been shown to lower blood pressure in both animals and humans, which may possibly be mediated via the PPARγ agonist-mediated inhibition of the renin-angiotensin-aldosterone system (RAAS) including the suppression of angiotensin (Ang) II type 1 receptor expression/Ang II-mediated signaling pathways and Ang II-induced adrenal aldosterone synthesis/secretion. PPARγ agonists also inhibited the progression of atherosclerosis in both animals and humans. PPARγ agonist-mediated inhibition of the RAAS and the thromboxane A2 system as well as endothelial protection may possibly be involved in the inhibitory effects on blood pressure and atherosclerosis. Furthermore, PPARγ agonists were demonstrated to have reno-protective effects, especially in reducing proteinuria in diabetic nephropathy in both animals and humans. The reno-protective effects of PPARγ agonists were also observed in non-diabetic renal dysfunctions. The effects may possibly be mediated via the PPARγ agonist-mediated blood pressure lowering, endothelial protection, and vasodilation of the glomerular efferent arterioles. Additionally, anti-neoplastic effects of PPARγ agonists have recently received much attention. PPARγ agonists, may therefore, be useful and effective against lifestyle-related diseases.