Background/Purpose: We have previously demonstrated that fasciitis is a common lesion of dermatomyositis (DM) detectable early after disease onset. Furthermore, en bloc biopsy showed that the fascial microvasculature, rather than intramascular microvasculature, is one of the primary sites for inflammatory cell infiltration (Arthritis Rheum. 2010;62:3751-9). We also showed that fasciitis was detectable by Power Doppler ultrasonography in patients with DM. In the current study, we examined whether angiogenesis was observed in fasciitis associated with DM, and which angiogenesis-related factors were expressed.

Methods: We analyzed 12 patients consisting of 6 newly diagnosed with DM and 6 newly diagnosed with polymiositis (PM) in the Division of Rheumatology at Jikei University Hospital. In the current study, all patients underwent en bloc biopsy before treatment. All samples were fixed in 10% neutral-buffered formalin and embedded in paraffin. Total vascular inflammation score (TVIS) was defined as the total number of aggregates of ≥50 perivascular inflammatory cells per 4-mm²area of the fascia in the 3 fields with the most remarkable perivascular infiltrates in order to evaluate the severity of fasciitis. Immunohistochemical staining was performed on paraffin-embedded sections by using anti-CD31 antibodies to evaluate angiogenesis, and anti-VEGF, anti-IL-6, and anti-TNF-α antibodies to evaluate the expression of angiogenesis-related factors in the fascia. Angiogenesis score (AS) was defined as the total number of CD31-positive blood vessels in the 3 high-power fields (200×) that showed the most remarkable proliferation of the vessels in the fascia. The numbers of VEGF,　IL-6, and TNF-α positive cells were counted in the 3 high-power fields (400×) that showed the largest accumulation of these positive cells.

Results: Significant fasciitis, histologically defined as TVIS of ≥3, was detected in all patients with DM. Although mild inflammation of the fascia (TVIS 1) was observed in 1/6 patients with PM, significant fasciitis was not detected in any patients with PM. TVIS and AS in the fascia were significantly higher in patients with DM compared with PM. AS was positively correlated with TVIS in DM-associated fasciitis. The numbers of VEGF and TNF-α positive cells were both significantly higher in the fascia of patients with DM compared with PM. IL-6 positive cells were barely present in the fascia among patients with DM and PM.

Conclusion: Angiogenesis was predominantly observed in the fascia with severe inflammation among patients with DM. Our data suggest that VEGF and TNF-α are involved in DM-associated fasciitis with angiogenesis. Inhibiting VEGF and TNF-α may be a useful therapeutic option to treat inflammatory myopathy, especially DM.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/angiogenesis-in-fasciitis-associated-with-dermatomyositis/