SIGNIFICANCE OF INCREASED ACCUMULATION OF TYPE-VI COLLAGEN AND TRANSFORMING GROWTH-FACTOR-BETA-1 IN TUBULOINTERSTITIAL DAMAGE IN HYPERTENSIVE NEPHROSCLEROSIS - AN IMMUNOHISTOCHEMICAL STUDY

The distribution of type VI collagen and transforming growth factor be ta 1 (TGF beta 1) was studied by immunohistochemistry in 12 renal biop sy specimens of hypertensive nephrosclerosis and five control cases. I n control kidneys, the immunostaining of type VI collagen was found in the mesangium, glomerular basement membrane and tubular basement memb rane. For TGF beta 1, mesangium, glomerular basement membrane, tubular basement membrane and tubular epithelial cells stained positively in the control kidneys. In contrast to the control cases, markedly increa sed immunostaining for both type VI collagen and TGF beta 1 was consis tently observed in tubulointerstitial damage in hypertensive nephroscl erosis. These immunohistochemical findings provide the evidence for a parallel increase of both type VI collagen and TGF beta 1 during the p rocess of tubulointerstitial injury in hypertensive nephrosclerosis. F rom the results of the present study, it is speculated that TGF beta 1 may contribute to the tubulointerstitial injury by stimulating increa sed synthesis of various extracellular matrix including type VI collag en.