Elevated glucose induction of thrombospondin-1 up-regulates fibronectin synthesis in proximal renal tubular epithelial cells through TGF-beta1 dependent and TGF-beta1 independent pathways.

Background: TGF-beta1 bioactivation, consequent to the interaction of latent TGF-beta1 with thrombospondin-1 (TSP-1), correlates with matrix accumulation in mesangial cells. Tubulointerstitial damage predicts poor renal survival. There is little data on TGF-beta1 bioactivation and matrix synthesis in human proximal renal tubular epithelial cells under the influence of high glucose concentrations.