Objective: To investigate peroxisome proliferator-activated receptor gamma (PPAR-gamma) expressions in patients with actively proliferating glomerulonephritis such as type IV lupus nephritis (LN) and cellular crescentic glomerulonephritis (RPGN).
Methods: All patients were divided into 4 groups as follows: RPGN (17 cases); LN type IV (15 cases); mild mesangial proliferative IgA nephropathy (IgAN, 7 cases) and minimal change disease (MCD, 10 cases). Clinical parameters, immunohisto-chemistry stain and in situ hybridization of renal biopsy specimens were performed.
Results: Clinically, proteinuria and hematouria were increased and Ccr were decreased in LN and RPGN patients, and increased ESR and decreased complement C3 were found in group LN. Active index of renal specimens were significantly higher in LN and RPGN groups than in IgAN and MCD groups. Renal specimens of MCD patients showed no positive PPAR-gamma staining in all sections; little immunoreactivity was detected in sections of glomerular, tubular and interstitial cells from IgAN patients. Glomerular positive staining of PPAR-gamma in renal sections in LN and RPGN patients[(3.3 +/- 1.8) and (2.8 +/- 1.2) cells per section of glomerulus, respectively] were significantly increased compared with that in IgAN patients [(0.7 +/- 0.5) cells per section of glomerulus]. Similarly, tubular positive staining of PPAR-gamma in LN and RPGN patients (27.38 +/- 12.46, 23.36 +/- 10.55) were also elevated compared with that in IgAN and MCD patients(6.51 +/- 3.49, 1.72 +/- 0.31). The relevance assay results showed positive relationship between active index and glomerular or tubular PPAR-gamma immunohisto-chemistry staining cell numbers (0.478, P < 0.01; 0.513, P < 0.01). Tubular PPAR-gamma mRNA expression in LN and RPGN patients was upregulated by in situ hybridization.
Conclusion: Our results demonstrate in vivo that PPAR-gamma expression was increased in active glomerulonephritis patients accompanied with clinical and pathological active inflammation. These data suggest that increase of PPAR-gamma expression in renal cells may play an important role in response to inflammatory stress.