ARTICLE IN PRESS FEEDBACK INHIBITION OF HIGH TGF-b 1 CONCENTRATIONS ON MYOFIBROBLAST INDUCTION AND CONTRACTION BY DUPUYTREN’S FIBROBLASTS

Myofibroblasts and TGF-b1 are implicated in Dupuytren’s contracture. Transforming growth factor b1(TGF-b1) (1–10 ng/ml) increases myofibroblast induction in Dupuytren’s fibroblasts and contraction in a collagen model. However, higher doses (20–30 ng/ml) inhibit contraction in dermal fibroblasts. We hypothesized higher doses of TGF-b1 would inhibit induction of myofibroblasts and contraction by Dupuytren’s fibroblasts. Increasing doses of TGF-b1 (0–30 ng/ml) were tested on Dupuytren’s fibroblasts using immunofluorescence to determine myofibroblast upregulation and a 3D collagen model used to determine contractile forces. Flexor retinaculum fibroblasts were used as controls. TGF-b1 induced myofibroblasts in Dupuytren’s fibroblasts (n 1⁄4 3) from 12% (0 ng/ml) to 23% (12.5 ng/ml) at 24 hours but dropped to 13% at 30 ng/ml (Po0.05). This response was mirrored in the contraction profiles. These trends were similar for flexor retinaculum fibroblasts (n 1⁄4 3), but contractile forces and myofibroblast induction were significantly less (Po0.001). This is the first report of negative feedback inhibition of TGF-b1 at higher concentrations in Dupuytren’s fibroblasts. Journal of Hand Surgery (British and European Volume, 2006) 31B: 5: 473–483