Distribution of ED-A and ED-B containing fibronectin isoforms in Dupuytren's disease.

Different fibronectin (FN) isoforms arise via alternate splicing of a single gene transcript in a cell- and tissue-specific manner. Antibodies were used to evaluate the presence and distribution of FN and its isoforms in Dupuytren's diseased and normal palmar fascia. Immunolocalization studies show extracellular FN fibrils, including FN isoforms containing extra domains A (A-FN) and B (B-FN), in proliferative and involutional stage Dupuytren's diseased tissue. However, B-FN appears less abundant and more restricted in its distribution as compared to A-FN or total FN. Total FN and A-FN are significantly reduced in residual tissue, while B-FN is not present. A-FN and B-FN are not present in normal palmar fascia, while total FN staining is slight and restricted to the loose connective tissue surrounding the large, parallel bundles of collagen fibers. The presence of A-FN and B-FN in Dupuytren's diseased palmar fascia represents a disease-induced appearance of these FN isoforms and further evidence of an association between Dupuytren's disease and wound healing.