Reduced growth of dermal fibroblasts from chronic venous ulcers can be stimulated with growth factors

Purpose: Although the slow healing rate of venous ulcers is well known, the underlying defect in the healing process is not weil understood. The purpose of this study was to examine the cellular characteristics of fibroblasts taken from venous ulcers (wound-fb) and compare them with the fibroblasts of normal tissue (normal-fb). Methods: Biopsy specimens were obtained from wound margins and normal tissue of the upper thigh in each patient. Dermal fibroblasts were isolated from explant cultures in Dulbecco's modified Eagle's medium supplemented with 10% calf serum. These cells were then plated at 1000 cells per plate, and total cells per plate mere counted over time so that growth curves could be generated. In further experimentation, media was supplemented with additional calf serum (20%, 30%, 40%, 50%) and growth factors (epidermal growth factor, basic fibroblast growth factor, interleukin-1 beta) in an attempt to stimulate growth. Results: Two major differences were noted: (1) normal-fb, replicated more rapidly than wound-fb; and (2) the morphologic features of wound-fb were different. Normal-fb were compact and tapered, with well-defined nuclear morphologic features. Wound-fb were larger and polygonal in shape, with less-uniform nuclear morphologic features. Additional calf serum in tissue culture media enhanced normal-fb growth but had no effect: on wound-fb. Supplementation of media with growth factors stimulated the growth of wound-fb. Statistically significant differences were noted at dap 10 and 14 with basic fibroblast growth factor supplementation (p = 0.02 and 0.0001, respectively) and at day 14 with epidermal growth factor (p = 0.008). Although interleukin-1 beta stimulated, cell growth in five of six patients, the differences observed were not statistically significant. Conclusions: Our data demonstrate that wound-fb proliferate at a slower rate and are morphologically distinct from normal-fb. These characteristics are typical of aged or senescent cells. This decreased growth can be stimulated by growth factors basic fibroblast growth factor, epidermal growth factor, and interleukin-1 beta. Slowed growth may be partially responsible for the defect in healing of venous stasis ulcers. Furthermore, we believe that in some patients ulcer healing may be improved by exogenous provision of specific growth factors.