Eyelid and Sternum Fibroblasts Differ in Their Contraction Potential and Responses to Inflammatory Cytokines

BACKGROUND Adverse skin scarring varies by anatomical site with, for example, presternal skin showing a greater hypertrophic response when compared with eyelid; such differences have traditionally been attributed to regional variations in skin tension, thickness, and Langer's lines. Fibroblasts are the main cell implicated in fibrosis, and they too are known to show anatomical variation in their expression, differentiation, and intercellular interactions. We, therefore, investigated whether intrinsic differences in skin fibroblasts derived from separate locations might contribute to the observed discrepancies in clinical scarring. METHODS Primary in vitro cultures were established using matched eyelid and presternal skin from 3 healthy donors undergoing blepharoplasty surgery. We used an in vitro collagen gel model of fibroblast-mediated tissue contraction to compare the properties of the dermal fibroblasts from each site. Cell contractile force and matrix stiffness were assessed in 3-dimensional tissue constructs using an automated high-throughput device. RESULTS Dermal fibroblasts isolated from eyelid and sternum differ both in their ability to contract a gel matrix and in their response to cytokine stimulation; despite having lower intrinsic contractile force (P < 0.01) and resting stiffness (P < 0.02), the presternal cells were more contractile (P < 0.001) following stimulation with serum, or inflammatory cytokines transforming growth factor-β (P < 0.01) and interleukin-1β (P < 0.05). CONCLUSIONS The propensity to cutaneous scarring may, at least in part, result from intrinsic differences in the local fibroblasts' ability to contract and their sensitivity to inflammatory cytokines. Improved understanding of the underlying molecular pathways should prove useful in identifying new therapeutic targets for altering surgical and other scarring.