Matrix metalloproteinases in inflammatory myopathies: enhanced immunoreactivity near atrophic myofibers.
OBJECTIVE
To further examine the role of proteolytic enzyme expression of matrix metalloproteinases (MMP) and T-cell markers in inflammatory myopathies and controls.


METHODS
We studied the expression of MMP-2, MMP-7, and MMP-9 in 19 cases of inflammatory myopathies and controls using immunocytochemistry.


RESULTS
Inflammatory myopathies showed distinct patterns of up-regulation of MMP. MMP-9 was strongly expressed in atrophic myofibers in all inflammatory myopathies. MMP-2 immunoreactivity was similar in its distribution, however, to a weaker intensity. In dermatomyositis the perifascicular atrophy showed pronounced MMP-9 immunoreactivity, probably reflecting denervated patterns of myofibers. Moreover, MMP-7 strongly immunolabeled invaded myofibers in polymyositis cases only.


CONCLUSIONS
These patterns confirm, that MMP-7 up-regulation is prominent in PM, while MMP-2 immunoreactivity is only slightly elevated in inflamed muscle. In general, MMP-9 up-regulation appears to be an important additional molecular event in the multistep process of all inflammatory myopathies.
Schoser
B G H
BG
Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximillians University Munich, Munich, Germany. benedikt.schoser@fbs.med.uni-muenchen.de
Blottner
D
D
Stuerenburg
H-J
HJ
D000328:Adult; D000368:Aged; D001284:Atrophy; D003882:Dermatomyositis / Q000201:enzymology; D006801:Humans; D007150:Immunohistochemistry; D020778:Matrix Metalloproteinase 2 / Q000032:analysis; D020783:Matrix Metalloproteinase 7 / Q000032:analysis; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D020782:Matrix Metalloproteinases / Q000032:analysis* / Q000276:immunology; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000473:pathology; D009220:Myositis / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology*; D018979:Myositis, Inclusion Body / Q000201:enzymology; D017285:Polymyositis / Q000201:enzymology; D015854:Up-Regulation
D020782:Matrix Metalloproteinases; D020783:Matrix Metalloproteinase 7; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9