Differences in alpha smooth muscle actin expression between fibroblasts derived from Dupuytren's nodules or cords.

Dupuytren's contracture is a fibrotic lesion of the palmar fascia that includes two distinct structures, the nodule and the cord. Histologically the Dupuytren's nodule has a high cell density with numerous myofibroblasts (alpha smooth muscle actin-expressing fibroblasts). The Dupuytren's cord has a rich connective tissue matrix containing a low density of elongated spindle-shaped fibroblasts. The cytoskeletal structures of cultured fibroblasts derived from Dupuytren's nodules and cords of surgically treated patients were studied and compared. Immunohistology showed no obvious morphological differences between Dupuytren's nodule and cord cultured cells, when focal adhesions (vinculin), intermediate filaments (vimentin), microtubules (alpha tubulin), or microfilaments (filamentous actin) were viewed. However, a greater proportion of nodule cultured cells were positive for alpha smooth muscle actin compared to cord-derived cells. The increased expression in nodule cells of alpha smooth muscle actin was confirmed by Western blot analysis. It appears that fibroblasts derived from Dupuytren's nodules or cords retain in vivo cytoskeletal characteristics, when grown in tissue culture.