Differential expression of the antioxidant repair enzyme methionine sulfoxide reductase (MSRA and MSRB) in human skin.

Recently, the antioxidant repair enzymes methionine-S-sulfoxide reductase A (MSRA) and methionine-R-sulfoxide reductase B (MSRB) were described in human epidermal keratinocytes and melanocytes. Methionine sulfoxide reductases (MSRs) are thought to protect against reactive oxygen species-induced oxidative damage in many organs, including the most environmentally exposed organ, human skin. We sought to examine the expression and distribution of this enzyme family (MSRA, MSRB1, MSRB2, and MSRB3) within the various compartments of healthy and diseased human skin. Expression was assessed using polyclonal MSR antibodies and immunohistochemical staining of human skin biopsies from various anatomical sites. Remarkably, MSRA expression was not only found in the epidermis as previously described but also in hair follicles and eccrine glands and was most pronounced in sebaceous glands. Furthermore, MSRB2 expression was found in melanocytes while MSRB1 and MSRB3 were both expressed within vascular endothelial cells. In conclusion, MSR enzymes are differentially expressed in human skin. Thus, modulation of MSR repair antioxidants may have implications for cutaneous aging and carcinogenesis.

Multinucleate giant cells in neurofibromas: a clue to the diagnosis of neurofibromatosis.

BACKGROUND: A 54-year-old African-American male patient underwent removal of several cutaneous neurofibromas. Histopathologic examination revealed a nonencapsulated, haphazardly arranged proliferation of slender spindle cells in a myxoid stroma consistent with neurofibroma. Interestingly, each specimen exhibited numerous, large, multinucleate giant cells with nuclei arranged in a wreath-like or linear pattern. Immunoperoxidase staining revealed these cells to be negative with S-100 and CD-34. It was subsequently learned that this patient has neurofibromatosis type 1 (NF1). METHODS: A retrospective review of all lesions coded as neurofibroma from our institution between 1 June 2006 and 28 August 2006 was performed. RESULTS: Biopsies of 53 cutaneous neurofibromas from 51 patients were reviewed. In these, multinucleate giant cells were present in only three (5.7%), all in patients with single lesions. CONCLUSIONS: Although the incidence of floret-like giant cells in neurofibromas of patients with NF1 is unknown, our findings suggest that the presence of these cells might be a clue to the presence of NF1.