Psoriasis, vitamin D and the importance of the cutaneous barrier's integrity: An update

Abstract

Psoriasis is a common, inflammatory, chronic, relapsing skin disease. Despite several hypotheses having been postulated to explain the pathogenesis of this disorder, nowadays it is considered as a T-cell-mediated disease; in this context an important role is played by vitamin D. The role of this micronutrient is important for many reasons: it is able to modulate the immune system; it is implicated in keratinocyte turnover; and it is involved in the integrity of the cutaneous barrier. In psoriasis, this molecule plays an important role due to its ability in the modulation of innate and adaptive immunity and by its antiproliferative and pro-differentiative effects on keratinocytes. Alteration of the metabolism of vitamin D may alter the cutaneous barrier integrity and favor an infective and inflammatory condition. The importance of vitamin D in the pathogenesis of psoriasis is not a mere mental exercise but may open further perspectives in the treatment of this disorder just preventing alterations of immune homeostasis, modulating the proliferation of keratinocyte, regulating the microbial flora and the response of the host to infective diseases.

Expression of Skin Barrier Protein Filaggrin in Skin Diseases without Atopic Dermatitis

“…Psoriasis is a common, inflammatory, chronic and relapsing skin disease with a prevalence of 1% -4% [16]. It is characterized by an abnormal keratinocyte proliferation and parakeratosis with vascular hyperplasia and infiltration of inflammatory cells into the dermis and epidermis.…”

“…The exact etiology of psoriasis remains unclear but recent evidence suggests the crucial role of active T-cells and cytokines in the inflammatory cascade [16].…”

Efeito do Mês de Nascimento no Risco de Desenvolver Psoríase

“…A vitamina D apresenta diversas funções como modulação do sistema imune, diferenciação dos queratinócitos e inibição da sua proliferação, 7 estando igualmente envolvida na integridade da barreira cutânea. 7 As alterações do metabolismo da vitamina D podem modificar a integridade da barreira cutânea e favorecer uma patologia inflamatória e/ ou infeciosa.…”

“…7 As alterações do metabolismo da vitamina D podem modificar a integridade da barreira cutânea e favorecer uma patologia inflamatória e/ ou infeciosa. 7 A vitamina D é capaz de suprimir a resposta inflamatória mediada por TLR (toll like-receptors), diminuir a produção e secreção de citoquinas pelas células mononucleares, 11 nomeadamente, de citoquinas da via Th1 e inibir a proliferação dos linfócitos T. 12 Para além disso, promove a autofagia nos macrófagos humanos ajudando na defesa de infeções oportunistas. 13 Sendo os linfócitos T as principais células do sistema imune adaptativo implicadas na fisiopatologia da psoríase, 3 a sua inibição terá claramente um papel favorável na evolução da patologia.…”

“English Disease”: Historical Notes on Rickets, the Bone–Lung Link and Child Neglect Issues

“…In the last two decades, an intense investigation around Vitamin D and its metabolism has been recorded identifying its important roles in cell signaling during both the adaptive and innate immune response to bacterial and viral infections [30,31,32,83,84,85,86,87,88,89,90]; for example, cholecalciferol in the management of tuberculosis (TB) [14,91,92]. In addition to the conventional T, B, and natural killer (NK) cells, there is a group of recently recognized innate lymphoid cells (ILCs) involved in mediating the host defense [93].…”