Effects of tacrolimus ointment on the expression of substance P, nerve growth factor, and neurotrophin‐3 in atopic dermatitis

Abstract

There is increasing evidence that neuropeptides may be involved in the pathogenesis of atopic dermatitis (AD). Objectives To investigate the effects of tacrolimus on the neuropeptides substance P (SP), nerve growth factor (NGF), and neurotrophin-3 (NT-3) in the skin, and SP and NGF in the serum, of patients with AD. Lesional skin specimens were obtained from eight AD patients and eight normal controls. For 8 weeks, AD patients applied 0.03% tacrolimus ointment to all affected areas twice daily. Blood samples and skin biopsies were then repeated. The participants' serum SP and NGF levels, as well as the SP, NGF, and NT-3 immunoreactive cell counts, were evaluated in the epidermal, dermal, and perivascular areas of lesional skin before and after treatment. The immunoreactive cell counts of SP, NGF, and NT-3 in skin were higher in AD patients than in normal controls. Most cell counts decreased significantly after treatment; however, the change in serum SP and NGF was not statistically significant. We demonstrated semiquantitative differences in neuropeptides in the skin of AD patients. In addition, topical tacrolimus reduced the levels of neuropeptides in the tissues of AD patients.