INCREASED EXPRESSION OF PLATELET-DERIVED GROWTH-FACTOR RECEPTOR-ALPHAAND RECEPTOR-BETA AND VASCULAR ENDOTHELIAL GROWTH-FACTOR IN THE SKIN OF PATIENTS WITH CHRONIC VENOUS INSUFFICIENCY

Growth factors produced by a variety of cells act as signalling peptid es through specific cell surface receptor pathways, Functions such as cell proliferation, migration and differentiation have been assigned t o each of them. Here, we report alterations of platelet-derived growth factor receptor alpha (PDGFR-alpha) and beta (PDGFR-beta) and vascula r endothelial growth factor (VEGF) expression patterns in the progress ive clinical stages of chronic venous insufficiency (CVI), A total of 30 punch biopsies were taken from patients with CVI, and VEGF and PDGF R were detected by indirect immunofluorescence and immunoperoxidase te chniques. PDGFR-alpha and PDGFR-beta expression was strongly increased in endothelial cells of capillaries, pericapillary cells and connecti ve tissue cells in the stroma of the skin of venous eczema and venous leg ulcer patients, and to a smaller extend in the dermis of those wit h lipodermatosclerosis. VEGF staining showed a similar expression patt ern in the progressive CVI stages. However, staining of vessels in par ticular might simply reflect binding of VEGF, secreted by keratinocyte s or fibroblasts, to its receptors, Growth factor and receptor express ion in specimens from telangiectases and reticular veins, and from pig mented areas, resembled that of normal skin, We conclude that PDGFR-al pha, PDGFR-beta and VEGF play an important role in mediating inflammat ion and epithelial hyperproliferation in venous eczema, inducing conne ctive tissue sclerosis in lipodermatosclerosis, and causing the reduce d reepithelialization tendency in venous ulcers, We speculate that end othelial proliferation with chronic venous hypertension might be media ted by these growth factors.