Proliferative Capacity of Venous Ulcer Wound Fibroblasts in the Presence of Platelet-Derived Growth Factor

Abstract

Growth factors have been demonstrated to increase the proliferation of wound fibroblasts. Platelet-derived growth factor (PDGF) is a potent cell mitogen. However, the role of PDGF in chronic venous ulcers is inconclusive. This study investigated whether PDGF stimulates venous ulcer fibroblasts to proliferate. Fibroblasts (fb) were isolated from 8 venous ulcers wounds (w-fb) and normal skin (n-fb) of the ipsilateral thigh via punch biopsies. Fibroblasts were plated at 1,500 cells/dish in Dulbecco's Modified Eagle Medium + 10% calf serum (CM) and treated with/without PDGF-ab (10 ng/mL) for 15 days. Growth rates were calculated. Western blotting and immunocytochemistry staining determined basal levels for PDGF-a and-b receptors, respectively. Growth rates were significantly lower in w-fb than in n-fb (1,579 ±546 vs 13,782 ±5,882 cells/day, p = 0.019). PDGF-ab treatment caused n-fb to increase their proliferative capacity relative to complete media (20,393 ±6,572 vs 13,782 ±5,882 cells/day, p= 0.005). However, PDGF-ab had no significant effect on w-fb proliferation over CM (1,030 ±264 and 1,579 ±546 cells/day, p=0.15). In the presence of PDGF-ab, w-fb had a significantly attenuated growth rate over n-fb (1,030 ±264 vs 20,393 ±6,572 cells/day, p=0.019). Western blot and immunocytochemistry analysis revealed diminished basal levels of PDGF-a and-b receptors, respectively, in ulcer fibroblasts. Venous ulcer fibroblasts had decreased proliferation. PDGF-ab had no effect on the growth rate of venous ulcer fibroblasts. In venous ulcers, decreased basal levels of fibroblast PDGF-a and-b receptors may explain reduced proliferation. Further clinical studies are needed to elucidate the role growth factors may play in venous ulcers.