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.

Physical and Mental Fatigue in Subjects Recovered from COVID-19 Infection: A Case-Control Study.

PURPOSE: Much effort has been directed toward studying COVID-19 symptoms; however, the post-COVID-19 phase remains mysterious. The aim of this work was to conduct a clinical and neurophysiological evaluation of physical and mental fatigue in COVID-19 long-haulers and to study whether markers of COVID-19 severity are able to predict the likelihood of developing postinfectious fatigue syndrome (PIFS) in such patients. PATIENTS AND METHODS: This case-control study was conducted on 46 COVID-19 long-haulers who met the criteria for PIFS and 46 recovered COVID-19 subjects without any residuals. Clinical assessment of fatigue was done using a fatigue questionnaire. Repetitive nerve stimulation and single-fiber electromyography were done after excluding neuropathy and myopathy. RESULTS: The median value for physical fatigue was 4 (IQR 2-7), while that for mental fatigue was 2 (IQR 0-3). Each day's increase in the period of COVID-19 illness increased the odds of PIFS in COVID-19 long-haulers 1.104-fold, and each unit increase in ferritin increased the odds of PIFS 1.006-fold. A significant decrement in at least one muscle was observed in 50% of patients. Patients with PIFS had significantly higher mean consecutive difference (MCD) in the extensor digitorum communis than the control group. There were statistically significant positive correlations between MCD values and physical, mental, and total fatigue scores. CONCLUSION: Higher ferritin levels and prolonged COVID-19 infection were independent predictors of PIFS in COVID-19 long-haulers. There was electrophysiological evidence of abnormalities in the peripheral portion of the motor unit in COVID-19 long-haulers with PIFS.