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Ischemia‐reperfusion (I/R) is associated with various pathogenic conditions, and there has been increasing evidence that cutaneous I/R injury is associated with the pathogenesis of pressure ulcers (PUs), especially at the early stage presenting as non‐blanchable erythema. Several studies demonstrated that oxidative stress is a key player in I/R injury, and the inhibition of oxidative stress may be capable of protecting tissue damage after I/R injury in various organs including skin. Dimethyl fumarate (DMF) approved by the Food and Drug Administration is Nrf2 activator, and recent studies revealed the antioxidative and anti‐inflammatory effects of DMF on I/R injury in animal models. Our objective was to assess the effects of oral administration of DMF on the development of PUs after cutaneous I/R injury in mice. We found that DMF administration significantly decreased the size of PUs after cutaneous I/R. Cutaneous I/R‐induced oxidative stress was also significantly inhibited by DMF in OKD48 mice, in which oxidative stress can be visually assessed. In addition, DMF treatment decreased hypoxic area, the numbers of apoptotic cells, and vascular loss in I/R area. DMF treatment suppressed the infiltration of MPO+ neutrophils and the production of proinflammatory cytokines in I/R site after cutaneous I/R injury. in vitro experiments, DMF treatment suppressed the production of reactive oxygen species in pericyte‐like cells. These results suggest that DMF treatment might prevent the formation of PUs induced by cutaneous I/R injury via suppressing oxidative stress and subsequent inflammation. DMF treatment during the early phase of decubitus ulcers might protect against further progression. [ABSTRACT FROM AUTHOR]

Objective: Several studies have demonstrated that the secreted glycoprotein and integrin ligand milk fat globule–associated protein with epidermal growth factor– and factor VIII–like domains (MFG‐E8) negatively regulates fibrosis in the liver, lungs, and respiratory tract. However, the mechanisms and roles of MFG‐E8 in skin fibrosis in systemic sclerosis (SSc) have not been characterized. We undertook this study to elucidate the role of MFG‐E8 in skin fibrosis in SSc. Methods: We assessed expression of MFG‐E8 in the skin and serum in SSc patients. We examined the effect of recombinant MFG‐E8 (rMFG‐E8) on latent transforming growth factor β (TGFβ)–induced gene/protein expression in SSc fibroblasts. We examined the effects of deficiency or administration of MFG‐E8 on fibrosis mouse models. Results: We demonstrated that MFG‐E8 expression around dermal blood vessels and the serum MFG‐E8 level in SSc patients (n = 7 and n = 44, respectively) were lower than those in healthy individuals (n = 6 and n = 28, respectively). Treatment with rMFG‐E8 significantly inhibited latent TGFβ–induced expression of type I collagen, α‐smooth muscle actin, and CCN2 in SSc fibroblasts (n = 3–8), which suggested that MFG‐E8 inhibited activation of latent TGFβ as well as TGFβ signaling via binding to αv integrin. In a mouse model of bleomycin‐induced fibrosis (n = 5–8) and in a TSK mouse model (a genetic model of SSc) (n = 5–10), deficient expression of MFG‐E8 significantly enhanced both pulmonary and skin fibrosis, and administration of rMFG‐E8 significantly inhibited bleomycin‐induced dermal fibrosis. Conclusion: These results suggest that vasculopathy‐induced dysfunction of pericytes and endothelial cells, the main cells secreting MFG‐E8, may be associated with the decreased expression of MFG‐E8 in SSc and that the deficient inhibitory regulation of latent TGFβ–induced skin fibrosis by MFG‐E8 may be involved in the pathogenesis of SSc and may be a therapeutic target for fibrosis in SSc patients. [ABSTRACT FROM AUTHOR]