Secretion of collagen type IV by human renal fibroblasts is increased by high glucose via a TGF-beta-independent pathway.

Background: Tubulointerstitial fibrosis is an important component of diabetic nephropathy, which is characterized by increased expression of interstitial extracellular matrix components and aberrant expression of the basement membrane component collagen type IV. The present study examined the effect of high ambient glucose and transforming growth factor-beta1 (TGF-beta1) on collagen secretion by human renal fibroblasts and proximal tubular epithelial cells (PTECs).

Methods: Human renal fibroblasts (TK173) and PTECs (HK2) were used to examine the effects of high glucose (25 mM d-glucose) and TGF-beta1 (1 ng/ml) on collagen type I, III and IV secretion compared with control medium (5.

Connective tissue growth factor and igf-I are produced by human renal fibroblasts and cooperate in the induction of collagen production by high glucose.

Tubulointerstitial fibrosis is an important component in the development of diabetic nephropathy. Various renal cell types, including fibroblasts, contribute to the excessive matrix deposition in the kidney. Although transforming growth factor-beta (TGF-beta) has been thought to play a major role during fibrosis, other growth factors are also involved.

Glucose-induced fibronectin and collagen type III expression in renal fibroblasts can occur independent of TGF-beta1.

Background: Various renal cell types have been shown to contribute to the excessive matrix deposition observed in diabetic nephropathy. The present study examined the effect of high ambient glucose and transforming growth factor-beta1 (TGF-beta1) on matrix production by human renal fibroblasts.

Methods: Human renal fibroblasts (TK173) were used to examine the effects of high glucose and TGF-beta1 on fibronectin and collagen type III expression.