Antiangiogenic VEGF Isoform in Inflammatory Myopathies

Objective. To investigate expression of vascular endothelial growth factor (VEGF) antiangiogenic isoformA-165bon human muscle in idiopathic inflammatory myopathies (IIM) and to compare distribution of angiogenic/antiangiogenic VEGFs, as isoforms shifts are described in other autoimmune disorders.Subjects and Methods. We analyzedVEGF-A165band VEGF-A by western blot and immunohistochemistry on skeletal muscle biopsies from 21 patients affected with IIM (polymyositis, dermatomyositis, and inclusion body myositis) and 6 control muscle samples. TGF-β, a prominent VEGF inductor, was analogously evaluated. Intergroup differences of western blot bands density were statistically examined. Endomysial vascularization, inflammatory score, and muscle regeneration, as pathological parameters of IIM, were quantitatively determined and their levels were confronted with VEGF expression.Results.VEGF-A165bwas significantly upregulated in IIM, as well as TGF-β. VEGF-A was diffusely expressed on unaffected myofibers, whereas regenerating/atrophic myofibres strongly reacted for both VEGF-A isoforms. Most inflammatory cells and endomysial vessels expressed both isoforms.VEGF-A165blevels were in positive correlation to inflammatory score, endomysial vascularization, and TGF-β.Conclusions. Our findings indicate skeletal muscle expression of antiangiogenicVEGF-A165band preferential upregulation in IIM, suggesting that modulation of VEGF-A isoforms may occur in myositides.