ALTERED EXPRESSION OF FIBROGENIC GROWTH-FACTORS IN IGA NEPHROPATHY AND FOCAL AND SEGMENTAL GLOMERULOSCLEROSIS

The profile of fibrogenic growth factor expression was assessed in bio psies from 27 patients with IgA nephropathy (IgAN), 14 focal and segme ntal glomerulosclerosis (FSGS) patients and 8 controls, by immunohisto chemistry. Increased platelet-derived growth factor (PDGF)-A and PDGF- B expression was detected in glomeruli and in vascular structures and collapsed tubules in the interstitium. Computer assisted image analysi s demonstrated increased glomerular PDGF-A in IgAN (P < 0.05), but not FSGS patients, compared to controls, suggesting an association with m esangial proliferation. PDGF receptors were prominent in areas of mesa ngial expansion and intertubular fibrosis. Significant increases in in terstitial PDGF Receptor beta (PDGFR-beta) were detected for both IgAN (P < 0.01) and FSGS (P < 0.05) patients. Interstitial PDGFR-beta expr ession was significantly correlated to monocyte/macrophage infiltrate (P < 0.0001). Increased basic fibroblast growth factor (bFGF) expressi on was observed segmentally in glomeruli, and in areas sf tubulointers titial damage. Higher proportions of patients with FSGS than IgAN had elevated interstitial bFGF (P < 0.005) and PDGF, reflecting the more s evere degree of vascular and tubulointerstitial injury in FSGS patient s. This study demonstrates distinct patterns of fibrogenic growth fact ors in IgAN and FSGS, strongly associated with the severity and type o f injury.