Aim: Peroxisome proliferator-activated receptor gamma (PPAR gamma) is generally accepted as renoprotective factor in type 2 diabetes mellitus, and PPAR gamma agonists have been reported to reduce albuminuria. However, little is known about renal PPAR gamma expression in chronic kidney disease, and especially human data are scarce. We hypothesized that renal PPAR gamma expression is associated with extent of proteinuria, kidney function, histological diagnosis and inflammatory mediators. Therefore, we investigated PPAR gamma mRNA expression in human kidney biopsies. Methods: We quantified PPAR gamma mRNA as well as the expression of macrophage chemoattractant protein-1, transforming growth factor beta-1 and interleukin-6 in 64 human kidney biopsies from patients with chronic kidney disease and mild-to-marked proteinuria of diverse aetiology. We measured renal function, and macrophage invasion was quantified by CD68 and vascularization by CD34 immunostaining. Results: PPAR gamma mRNA expression correlated inversely with renal function. Higher blood pressure levels were associated with higher PPAR gamma expression levels. PPAR gamma mRNA expression correlated significantly (P <0.001) with macrophage chemoattractant protein-1 mRNA expression and showed a negative trend with transforming growth factor beta-1 mRNA expression. No differences in PPAR gamma expression were detected with regard to extent of proteinuria, histological diagnosis, macrophage invasion, interleukin-6 expression, and age or body mass index. Conclusions: PPAR gamma expression increases with loss of renal function and may be an important factor in maintaining normal renal function serving as a key protective mechanism to renal injury.
- renal insufficiency