ESCHERICHIA-COLI TUBULAR CELL-INTERACTION MODULATES RENAL MEDULLARY INTERSTITIAL CELL-PROLIFERATION AND COLLAGEN ACCUMULATION

In order to investigate the role of bacterial infection in the mediati on of interstitial scarring, we examined the effect of Escherichia col i-tubular cell interaction products (ECS) and control tubular cell pro ducts (CS) on rat renal medullary interstitial cell (RMIC) proliferati on and collagen accumulation. ECS enhanced (p < 0.001) RMIC proliferat ion when compared with CS and media alone. ECS, at concentrations of 5 , 10, 15, 20, and 25%, increased (p < 0.001) RMIC proliferation, where as at higher concentrations (30-70%), ECS attenuated (p < 0.001) RMIC proliferation when compared with CS and media alone. ECS-induced RMIC proliferation was attenuated (p < 0.001) by interleukin-6 antibody (EC S 31,800 +/- 230; ECS + interleukin-6 antibody 16,400 +/- 120 cells/we ll). ECS at concentrations of 20 and 30% enhanced (p < 0.001) RMIC col lagen type III accumulation. Transforming growth factor beta antibody attenuated (p < 0.001) RMIC collagen accumulation induced by ECS (ECS 157 +/- 8; ECS + transforming growth factor beta antibody 83 +/- 10 ng /mg cellular protein). Moreover, ECS also increased mRNA expression of transforming growth factor beta in RMIC as compared with CS and media . The present in vitro study provides a basis for speculation that bac teria-tubular cell interaction may contribute to the development of in terstitial scarring.