The mesenchymal stem cell profile in psoriasis

Background The expression of inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor (VEGF) and the level of total oxyradical scavenging capacity have been evaluated extensively in the cutaneous cells of patients with psoriasis. As yet, no indications are available about the undifferentiated cells, the mesenchymal stem cells (MSCs), isolated from skin. Objectives To isolate MSCs in patients with psoriasis and to compare them with those obtained from atopic and healthy subjects, in order to analyse whether MSCs show some typical psoriatic profiles and to understand whether pathophysiological events leading to psoriasis start early at the stem cell level. Methods MSCs isolated from seven patients with psoriasis, seven patients with acute atopic dermatitis and seven healthy subjects were characterized by fluorescence-activated cell sorting analysis. VEGF and nitric oxide (NO) content was measured in conditioned medium, the expression of VEGF and iNOS was analysed by immunohistochemistry, and the total oxyradical scavenging capacity towards peroxynitrite was tested. Results VEGF content was highest in the medium conditioned by psoriatic perilesional MSCs, whereas NO concentration was maximally increased in medium conditioned by MSCs isolated from lesional psoriatic skin. The ability to neutralize the oxidizing effects of peroxynitrite was lower for MSCs isolated from lesional psoriatic skin compared with other MSCs, except for MSCs of lesional atopic skin. Conclusions The microenvironment in psoriasis differs from those of atopic dermatitis and healthy skin; it could induce resident MSCs to produce angiogenic and proinflammatory mediators which lead to a reduction in the antioxidant capacity of these cells, contributing to the development of skin lesions in psoriasis.