L9.      Human hair follicle and dermal fibroblasts have different responses to estrogens after wounding in vitro.
Susan Stevenson*, Louisa Nelson, Shahid Huq*, Shola Adekunle*, Kamil Asaad*, David Sharpe*, Julie Thornton; Burns and Plastic Surgery Research Unit and *Department of Biomedical Sciences, University of Bradford, Bradford, UK.

Improved wound healing in hairy skin is thought to involve hair follicle fibroblasts. Wound healing is delayed in post-menopausal women, but is improved with estrogen therapy. Since we have previously reported that human dermal fibroblasts and dermal papilla cells express estrogen receptors, we have evaluated the migration, proliferation and collagen secretion of cultured breast and scalp dermal fibroblasts, and scalp follicular dermal papilla and dermal sheath cells in response to 17beta-estradiol following mechanical wounding. Primary cultures of dermal fibroblasts (n=8), dermal sheath (n=4) and dermal papilla cells (n=4) were established from female scalp skin or from breast skin (fibroblasts only n=5). Cells were mechanically wounded and incubated in serum-free, phenol red-free medium +/- 10nM 17beta-estradiol. Migration was evaluated using a scratch-wound assay, DNA synthesis by 3H-thymidine uptake and collagen secretion by the Sircol assay. Post wounding, all cells demonstrated a significant increase in DNA synthesis. Dermal fibroblasts derived from breast showed a further significant increase in response to 17beta-estradiol. Post-wounding, scalp fibroblasts and dermal sheath cells migrated at similar rates, significantly faster than breast fibroblasts. However, the rate of migration of the dermal papilla cells was significantly faster than all groups. Incubation with 17beta-estradiol significantly increased the migration of both breast and scalp dermal fibroblasts, but had no effect on hair follicle fibroblasts. Wounding significantly increased the secretion of collagen by breast and scalp fibroblasts; 17beta-estradiol had no effect on collagen secretion by any of the cell lines. These results demonstrate that wounding stimulates migration and proliferation in cultured follicular fibroblasts, supporting the hypothesis that these cells play a role in wound healing. Furthermore, following wounding estrogen directly stimulates dermal fibroblast proliferation and migration in vitro, supporting the improved wound healing rates seen with estrogen therapy. Whether 17beta-estradiol has indirect effects on hair follicle cells is currently under investigation.