Intragraft expression of transforming growth factor β1 gene in isolated glomeruli from human renal transplants

Abstract

Background Experimental evidence suggests that transforming growth factor (TGF) β1 is a fibrogenic cytokine. The histopathological changes of chronic renal allograft nephropathy are dominated by fibrotic changes and TGF-β may have an important aetiological role. This study investigated the relationship between intragraft TGF-β gene expression and extracellular matrix protein deposition in human renal allografts. Methods Sixteen cadaveric renal transplant recipients immunosuppressed with cyclosporin and steroids were studied. Individual glomeruli were isolated from protocol needle-core biopsies and, following messenger RNA extraction, intragraft gene expression was studied by reverse transcriptase–polymerase chain reaction. Collagen III deposition in these renal transplant biopsies was examined by immunohistochemistry and quantified by computerized histomorphometry. Results There was a positive correlation between renal cortical collagen III immunostaining and the levels of glomerular complementary DNA for TGF-β1. Conclusion TGF-β1 is a profibrotic influence in human renal transplants. The methods described should prove of benefit in investigating the mechanisms of chronic renal allograft damage.