INCREASED EXPRESSION OF PLATELET-DERIVED GROWTH-FACTOR-A AND COLLAGENOUS MATRIX PROTEINS IN CONGENITAL MULTICYSTIC RENAL DYSPLASIA

The expression of platelet-derived growth factor A (PDGF-A), and its s patial and temporal relationship to interstitial collagens in kidneys with congenital multicystic dysplasia using in situ hybridization, hav e been examined. Seventeen dysplastic kidneys (16 weeks to 7 months) a nd 30 normal age-matched controls were used in the study. Increased PD GF-A mRNA was detected in dysplastic compared to normal kidneys in all age groups including extensively fibrotic postnatal kidneys. An abund ant PDGF-A mRNA signal was seen within the epithelial cells of cystica lly dilated or dysplastic tubules and within interstitial fibroblasts and disorganized primitive mesenchyme. A comparable amount of PDGF-A p rotein was detected by Western blotting. Procollagen I and III mRNA we re increased in fibroblasts surrounding cystic and dysplastic tubules. We conclude that tubular epithelial production of PDGF-A may induce c ollagenous matrix production by adjacent fibroblasts, while marked up- regulation of PDGF-A by interstitial cells may be responsible for sust ainable fibrogenic effects in the fetal kidney contributing to renal m aldevelopment.