Vasoactive intestinal polypeptide and substance P in the pathogenesis of atopic dermatitis

Neurogenic components are probably involved in the pathogenesis of atopic dermatitis (AD) and several neuropeptides have been implicated in the mechanisms underlying this disease. The aim of the present study was to evaluate by radio-immunoassay (RIA), the vasoactive intestinal polypeptide (VIP) and substance P (SP) content in whole-skin homogenates of AD lesions. RIA was performed using an antiserum, AH78, recognizing the carboxy-terminal fragment VIP (22-28) and a polyclonal antiserum directed against SP. VIP levels were markedly increased in lesional AD skin (5.62 +/- 1.25 pmol/g tissue) vis-à-vis controls (0.43 +/- 0.08 pmol/g tissue), whereas SP levels were significantly lower in lesional skin (0.25 +/- 0.03 pmol/g tissue) than in normal skin (0.97 +/- 0.24 pmol/g tissue). The results confirm that VIP and SP are relevant to the pathogenesis of AD and their imbalance might reflect diverse roles of these NP in the modulation of AD lesion.