Relationship Between Capillary and Muscle Damage in Dermatomyositis

Abstract

To assess the pathogenetic importance of capillary damage and its relationship with degenerating muscle fibers in dermatomyositis (DM), an electron microscope study of eight muscle biopsy specimens (adult and juvenile forms) and seven muscle specimens from patients with other neuromuscular diseases was conducted. There was a 49% reduction of capillaries in the muscle specimens of DM patients. Capillary damage also was more frequent in the DM group than in control group (p less than 0.001). We found a striking relation between capillary and muscle damage in the DM group (p less than 0.002) but not in the control group. The diagnostic value of undulating tubules within endothelial cells is also discussed.

Signs of inflammation in both symptomatic and asymptomatic muscles from patients with polymyositis and dermatomyositis

“…2 5 Involvement of microvessels in the disease mechanisms of dermatomyositis was already proposed by the observation of a decreased number of capillaries in patients with dermatomyositis, even in patients with early disease without inflammatory infiltrates. [14][15][16][17] To further determine the role of the observed phenotypes of microvessels with IL1a expression and that of muscle fibres with MHC class I expression in causing clinical symptoms, we compared the expression of these molecules in two different muscles from the same patient, one from a clinically symptomatic (ie, with subjective muscle weakness) and the other from a clinically asymptomatic muscle. We also investigated histopathological changes, cellular infiltration of T cells and macrophages in the same biopsy specimens.…”

Fatal muscle haemorrhage attributable to heparin administration in a patient with dermatomyositis

“…Electron microscopy of muscle samples from patients with dermatomyositis showed an approximately 50% reduction in the number of capillaries compared with controls with other neuromuscular diseases. 4 We believe that the muscular haematoma in our patient was attributable to capillary damage. Gastro-intestinal haemorrhage has been reported in patients with dermatomyositis.…”

“…Others have reported that the capillaries are early and specific targets of the disease process; 3 a muscle specimen with minimal structural alterations exhibited focal capillary depletion and a significant reduction in capillary density. Electron microscopy of muscle samples from patients with dermatomyositis showed an approximately 50% reduction in the number of capillaries compared with controls with other neuromuscular diseases 4 …”

Dermatomyositis complicated with hemorrhagic shock of the iliopsoas muscle on both sides and the thigh muscle

“…Others have reported that the capillaries are early and specific targets of the disease process [3]; a muscle specimen with minimal structural alterations exhibited focal capillary depletion and a significant reduction in capillary density. Electron microscopy of muscle samples from patients with dermatomyositis showed an approximately 50% reduction in the number of capillaries compared with controls with other neuromuscular diseases [4]. We believe that the muscular hematoma in our patient was attributable to capillary damage.…”

“…The inflammatory mechanism is attributed to a primary T-helper-celldependent, B-cell-mediated, local humeral immune mechanism, which causes vascular occlusion and capillary obliteration with ischemic change in the skin and muscle [1,2]. There have been a few reports of dermatomyositis causing hemorrhagic myositis [3,4,5]. We present a patient being treated for dermatomyositis complicated with shock resulting from hemorrhage in the iliopsoas muscle on both sides and the thigh muscle.…”