PPAR-gamma-agonists' renal effects

PPAR-gamma ligands, including thiazolidinediones, have recently become clinically available for treating insulin-resistant diabetes mellitus. Accumulating evidence suggests that these drugs not only significantly improve insulin sensitivity but also may have antiproteinuric effects in genetically obese diabetic rodents and patients with type II diabetes and diabetic nephropathy. Moreover, troglitazone reduced expression of ECM proteins and transforming growth factor-beta in glomeruli from streptozotocin-induced diabetic rats. Many other properties including antiproteinuric, hemodynamic, and antihypertensive effects in insulin-dependent diabetes mellitus suggest that PPAR-gamma ligands might have a direct, beneficial renal effect, independent of their capacity to improve glucose tolerance. Besides their antidiabetic effects, thiazolidinediones have been shown to lower blood pressure in diabetic patients with hypertension and patients with diabetic nephropathy through multiple mechanisms. Several studies showed the efficacy of PPAR-gamma agonists to ameliorate the progression of glomerulosclerosis. The effect is independent of insulin effects and could only be partially due to lipid effects. These renal protective effects of PPAR-gamma agonists suggest that they may provide a novel intervention strategy to prevent vascular and glomerular sclerosis.