Artikel
Pathomechanisms in dermatomyositis, polymyositis and necrotizing myopathie: role of endothelial progenitor cells
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Veröffentlicht: | 29. August 2016 |
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Gliederung
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Background: The pathogenesis of dermatomyositis (DM) is believed to rely on humoral mechanisms, whereas the hypothesized cause of polymyositis (PM) are cytotoxic T cells. Necrotizing myopathy (NM) is histopathologically characterized by necrosis of muscle fibres in absence of inflammation. Presuming that cells of the immune system immigrate from small vessels of the affected muscle, significant endothelial dysfunction may be present in the three diseases. Moreover, vessels in DM have been shown to become massively destructed. Endothelial progenitor cells (EPCs) are required for neovascularization upon ischemic damage. Aim of this project was to analyze the presence and functional alteration of EPCs in DM, PM, NM and healthy controls.
Methods: Thirty-two patients (DM 16, PM 9, NM 7) and 24 healthy controls were included into the study. The following EPC-related parameters were evaluated: blood-derived EPC colonies (culture assay) and peripheral circulating EPCs (CD133+/KDR+ cells - cytometric analysis). Muscle biopsies were available from 10 patients with DM, from 6 with PM and from 6 with NM. Cryosections from muscle biopsies were stained with markers for CD31 (endothelium), Nestin (regeneration of mature endothelial cells), MHC (inflammation) and CXCR6 (T-lymphocyte receptor for tissue recruitement) and evaluated by immunofluorescence followed by manual multi-parameter assessment.
Results: Blood-derived EPC colonies were significantly lower in NM, PM and DM as compared to healthy controls. Staining of musclebiopsies revealed strong signals for Nestin in NM, PM and DM and showed strong signals for MHC-I in PM and DM. The marker of endothelial regeneration Nestin showed an even more positive trend in DM, PM and NM as compared to CXCR6 and MHC-I. The marker of inflammation (MHC-I) and the marker of regeneration (Nestin) significantly correlate with each other in DM and PM, but not in NM.
Conclusion: The data suggest that (I) impairement of the EPC system may perpetuate vascular damage in DM / PM / NM. (II) Higher abundances of intramuscular nestin suggest that mature endothelial cells ‘attempt’ to endogenously neutralize affected EPC competence.