GROWTH-FACTOR TRANSCRIPTS IN RAT RENAL-TRANSPLANTS

Locally produced cytokines and growth factors may mediate tissue remod elling processes, as observed in renal transplants exposed to ischemia or acute rejection episodes, The present study was designed to invest igate mRNA transcript levels of platelet-derived growth factor (PDGF)- receptor beta, PDGF-A, PDGF-B, fibroblast growth factor-1, and transfo rming growth factor beta(1) in normal rat kidneys, in kidneys followin g contralateral nephrectomy and in renal transplants with acute or chr onic rejection, Platelet-derived growth factor-receptor beta mRNA leve ls increased significantly in syngeneic and allogeneic transplants in the first week after transplantation and in allogeneic transplants wit h chronic rejection, Immunohistochemistry showed induction of PDGF-rec eptor beta protein expression on vascular wall cells in such grafts, P latelet-derived growth factor-A chain mRNA levels increased in day 3 a llografts and in syngeneic LEW grafts, while PDGF-B chain mRNA levels showed no significant changes with transplantation. Fibroblast growth factor-1 mRNA levels were detectable in normal kidneys, tended to decr ease with acute rejection, and increased significantly in chronic reje ction, Transforming growth factor-P, transcripts increased in acute an d chronic rejection; immunohistochemistry showed predominantly glomeru lar localization of the transforming growth factor-beta(1) protein, We conclude that transplantation and rejection are associated with chang es in the intragraft mRNA levels for several growth factors; chronic r ejection is characterized by an increase in fibroblast growth factor-1 and transforming growth factor-beta(1) transcript levels. (C) 1996 by the National Kidney Foundation, Inc.