Growth factors produced by a variety of cells act as signalling
peptides through specific
cell surface receptor pathways. Functions such as cell proliferation, migration and differentiation have been assigned to each of them. Here, we report alterations of
platelet-derived growth factor receptor alpha (PDGFR-alpha) and
beta (PDGFR-beta) and
vascular endothelial growth factor (
VEGF) expression patterns in the progressive clinical stages of chronic
venous insufficiency (CVI). A total of 30 punch biopsies were taken from patients with CVI, and
VEGF and PDGFR were detected by indirect immunofluorescence and immunoperoxidase techniques. PDGFR-alpha and
PDGFR-beta expression was strongly increased in endothelial cells of capillaries, pericapillary cells and connective 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 with
lipodermatosclerosis.
VEGF staining showed a similar expression pattern in the progressive CVI stages. However, staining of vessels in particular might simply reflect binding of
VEGF, secreted by keratinocytes or fibroblasts, to its receptors.
Growth factor and receptor expression in specimens from
telangiectases and reticular veins, and from pigmented areas, resembled that of normal skin. We conclude that PDGFR-alpha,
PDGFR-beta and
VEGF play an important role in mediating
inflammation and epithelial hyperproliferation in venous
eczema, inducing connective tissue
sclerosis in
lipodermatosclerosis, and causing the reduced reepithelialization tendency in
venous ulcers. We speculate that endothelial proliferation with chronic venous
hypertension might be mediated by these
growth factors.