REGULATION OF PROLIFERATION AND PLATELET-DERIVED GROWTH-FACTOR EXPRESSION IN PALMAR FIBROMATOSIS (DUPUYTREN CONTRACTURE) BY MECHANICAL STRAIN

Palmar fibromatosis (Dupuytren contracture) causes fibrosis of specifi c palmar fascial bands. These bands are subjected to repetitive mechan ical strain in situ. Primary cell cultures were derived from (a) palma r fibromatosis from eight patients, (b) uninvolved palmar fascia (Skoo g's fibers) from four of these patients, and (c) normal palmar fascia from four additional patients. The cells were plated onto collagen-coa ted membranes either subjected to cyclic strain (25% maximal strain at 1 Hz) or without strain. Bromodeoxyuridine incorporation showed an in crease in proliferation in all cultures subjected to strain. This incr ease was highest for palmar fibromatosis (10 to 40% nuclear incorporat ion, p = 0.02). Skoog's fibers and fascia from the normal individuals showed a trend (not significant) toward increase with strain (8 to 25% , p = 0.15 for Skoog's fibers, and 8 to 15%, p = 0.45 for normal fasci a.). Cyclic strain increased the expression of platelet-derived growth factor-A relative to glyceraldehyde-3-phosphate dehydrogenase in palm ar fibromatosis (2.2 to 3.5, p = 0.05) and Skoog's fibers (0.8 to 2.0, p = 0.04). The expression of platelet-derived growth factor-B relativ e to glyceraldehyde-3-phosphate dehydrogenase was enhanced by cyclic s train only in the fibromatosis tissue (0.7 to 2.1, p = 0.04). The norm al fascia did not express platelet-derived growth factor. Platelet-der ived growth factor neutralizing antibody decreased bromodeoxyuridine i ncorporation in fibromatosis cultures subjected to cyclic strain to ne ar levels for those grown in the absence of strain (38 to 16%, p = 0.0 5). Conditioned medium from fibromatosis cells grown under stain showe d a trend toward increased proliferation in additional fibromatosis cu ltures compared with conditioned medium from fibromatosis cells grown without strain (9 to 15% nuclear incorporation, p = 0.20). The observe d palmar fibromatosis contracture can be partially explained on the ba sis of the cell's response to cyclic strain, which may be mediated by platelet-derived growth factor.