The efficacy of in vivo administration of Apremilast on mesenchymal stem cells derived from psoriatic patients

Introduction: Psoriasis cellular hallmarks, such as the imbalance between Th1/Th17 and Th2 cytokines and the dysregulated expression of vascular endothelial growth factor (VEGF), inducible nitric oxide synthase, (iNOS) and indoleamine 2,3-dioxygenase (IDO), are all detectable in mesenchymal stem cells (MSCs) suggesting that psoriasis originates at mesenchymal level. Aim of the study: In this scenario, MSCs may become the new therapeutic target and interest in the effects of traditionally used drugs, such as Apremilast, on MSCs has greatly increased. Materials and Methods: MSCs from control subjects (C-MSCs) and from psoriatic patients before (PsO MSCs T0) and after in vivo treatment with Apremilast (PsO-MSCs T12) were isolated and characterized; subsequently, the effects of Apremilast on VEGF, iNOS and IDO expression were evaluated by immunocytochemistry (ICC). The expression of VEGF, iNOS and IDO was also detected in skin sections by immunohistochemistry (IHC). Results: The results indicate that in vivo administration of Apremilast is able to drive the altered profile of PsO-MSCs towards a more physiological pattern. In skin sections, the role of Apremilast is evident in reducing VEGF, iNOS and IDO expression. Conclusion: Apremilast treatment influences the expression of VEGF, iNOS and IDO not only by keratinocytes but also by MSCs, restoring their intrinsic profile and their natural anti-inflammatory action, and decreasing the auto-inflammatory process that underpins the development of psoriasis.