Matrix metalloproteinases in inflammatory myopathies: enhanced immunoreactivity near atrophic myofibers
Abstract:Objectives– To further examine the role of proteolytic enzyme expression of matrix metalloproteinases (MMP) and T-cell markers in inflammatory myopathies and controls. Material and 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. Conclusion– 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.
Document Type: Original Article
Affiliations: 1: Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximillians University Munich, Munich, Germany, 2: Department of Anatomy I, Neurobiology Section, University Hospital Benjamin Franklin, Freie Universität Berlin, Berlin, Germany, 3: Department of Neurology, University Clinic Hamburg-Eppendorf, Hamburg, Germany
Publication date: April 1, 2002