MicroRNA-22 Level in Patients with Multiple Sclerosis and Its Relationship with Vitamin D and Vitamin D Receptor Levels.

INTRODUCTION Multiple sclerosis (MS) is known to be a multifactorial disorder. Numerous observational studies have suggested the implication of multiple genetic and environmental factors in the pathogenesis of MS. The aim of this work was to evaluate expression of the microRNA-22 (miRNA-22) level, in relation to vitamin D (VD) and VD receptor (VDR) levels in patients with MS during remission state. METHODS This case-control study was conducted in 50 patients with clinically definite MS and 50 age- and sex-matched healthy controls. miRNA-22 expression was assessed in both MS patients and controls using quantitative RT-PCR. The serum level of VD and VDR was assessed in both MS patients and controls using ELISA techniques. RESULTS The miRNA-22 level was significantly downregulated in MS patients in comparison to controls (p value <0.001). MS patients had also significantly lower VD and VDR levels in comparison to controls (p value <0.001 and <0.001, respectively). Patients with secondary progressive MS (SPMS) have a significantly higher miRNA-22 level than patients with relapsing remitting MS (RRMS) (p value = 0.042). There was a statistically significant positive correlation between the miRNA-22 level and EDSS (p value = 0.033). There was also a statistically significant positive correlation between the miRNA-22 level and VDR level (p value = 0.002). CONCLUSION The miRNA-22 level was significantly downregulated in MS patients, but it had a positive correlation with disability status. Patients with SPMS have a significantly higher miRNA-22 level than patients with RRMS. VD and VDR levels were significantly lower in MS patients than controls. The miRNA-22 level was positively correlated with the VDR level.