The Journal of Bone and Joint Surgery, Vol 69, Issue 9 1400-1407, Copyright © 1987 by Journal of Bone and Joint Surgery, Inc
Extracellular matrix-cytoskeletal connections at the surface of the specialized contractile fibroblast (myofibroblast) in Dupuytren disease
JJ Tomasek, RJ Schultz and CJ Haaksma
Department of Orthopaedic Surgery, New York Medical College, Valhalla 10595.
The cellular basis of contracture of the palmar fascia in patients who have
Dupuytren disease involves the generation of intracellular force and the
transmission of this force to the surrounding tissue. A specialized cell,
the myofibroblast, supposedly generates this intracellular force. Recently
published studies from our laboratory demonstrated that the cytoskeleton of
the myofibroblast contains non-muscle myosin and not smooth-muscle myosin,
suggesting that it utilizes a non-muscle contractile system. In addition,
these studies identified the extracellular glycoprotein fibronectin, not
the basal-lamina-specific glycoprotein laminin, at the surface of
myofibroblasts, suggesting that the transmission of the intracellular force
to the surrounding tissue also occurs by a non-muscle mechanism. Because of
the lack of proteins that are specific to smooth muscle in the specialized
cell in Dupuytren disease, we prefer the term specialized contractile
fibroblast to describe this type of cell. To determine the mechanism by
which the intracellular force may be transmitted to the surrounding tissue,
we examined the ultrastructure of the connection of the cytoskeleton of the
specialized contractile fibroblast to the surrounding extracellular matrix.
By electron microscopy, extracellular filamentous material was identified
at the surface of the specialized contractile fibroblast. These
extracellular fibrils were found to be in close association with
intracellular bundles of actin microfilaments, resulting in specialized
transmembranous associations at the surface of the specialized contractile
fibroblast. Bundles of filamentous extracellular material were found to
extend from the surface of the specialized contractile fibroblast,
connecting it with the surrounding matrix and also with adjacent
specialized contractile fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)