Role of liver X receptors a and b in psoriasis

Background Psoriasis is a chronic inflammatory disease of the skin characterized by an accelerated rate of keratinocyte proliferation, abnormal differentiation of epidermal keratinocytes, alteration in dermal angiogenesis, and increased production of proinflammatory cytokines. The activation of liver X receptors (LXRs) stimulates keratinocyte differentiation, and exerts an antiproliferative effect on keratinocytes and an inhibitory effect on epidermal cytokines. Objective To determine whether there is a change in the expression of LXRsa and b in psoriatic skin, and whether this change (if present) is related to the severity of psoriasis or not. Patients and methods In this case control study, 25 patients with psoriasis vulgaris and 25 healthy volunteers who served as controls were included. Punch skin biopsies from sun-protected areas were taken from the lesional skin of the patients as well as from the normal skin of the control group and subjected to a quantitative PCR examination of LXRa and b mRNA. Results The mean values of LXRa and b in the lesional skin of psoriatic patients were significantly lower than those in the control group (Po0.001, for both LXRa and b). Correlation of the levels of LXRa and b in the lesional skin of psoriatic patients of the studied cases with their Psoriasis Area Severity Index score showed a statistically significant inverse correlation. Conclusion The study showed that LXRs may play a role in the pathogenesis of psoriasis. Further studies are also recommended to evaluate the use of LXR agonist as a new therapy.