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INTRODUCTION: Few studies have explored the intricate connections between vitamin D receptor (VDR) gene polymorphisms, VDR, tight junction (TJ) protein expression and clinical features of atopic dermatitis (AD). METHODS: From 43 adult AD patients, VDR polymorphisms were genotyped from peripheral blood samples using polymerase chain reaction-restriction fragment length polymorphism. VDR, occludin, claudin-1 and ZO-1 protein expression from skin lesion biopsies were assessed by immunohistochemistry. RESULTS: The A1012G heterozygous VDR polymorphism exhibited a lower odds ratio (OR) for juvenile AD onset (OR: 0.046, 95% CI 0.004-0.51, p=0.012). In contrast, the presence of ≥2 homozygous VDR polymorphisms were significantly associated with positive skin prick test (SPT) (10/20, 50%) vs. negative SPT (1/23, 4.3%; p=0.0003). The most highly expressed TJ proteins in lesions of AD patients were claudin-1 and zonulin-1 (ZO-1), while VDR and occludin were less prevalent. A significant correlation was observed between ZO-1 expression and a body mass index ≥30 kg/m2 (OR: 12.1, 95% CI 1.06-137.9, p=0.045). Claudin-1 expression was associated with a positive SPT (OR: 8.23, 95% CI 1.04-65.5, p=0.046) and serum 25(OH)D levels were negatively correlated with ZO-1 expression (rho= -0.43, p=0.0058). CONCLUSION: This study provides novel insights into the relationship between VDR gene polymorphisms, VDR, TJ protein expression, and clinical features in adult AD patients, highlighting a significant role of vitamin D in the pathophysiology of this disease.
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PURPOSE: Low vitamin D levels were reported to negatively influence the outcomes of acute COVID-19, as well as other biochemical markers were linked to COVID-19, including microRNAs (miRNAs). This study aimed to prospectively evaluate miRNAs and vitamin D relationship in predicting COVID-19 outcomes. METHODS: COVID-19 patients were part of a previously reported cohort and enrolled in a matched-ratio based on the presence/or not of severe disease at hospital admission. 25(OH) vitamin D levels and miRNAs expression were evaluated. RESULTS: Patients affected by non-severe COVID-19 were characterized by a higher expression of miRNAs hsa-miR-3115 and hsa-miR-7151-3p, as compared to those affected by severe disease. In non-severe patients, these miRNAs were more frequently expressed in those who subsequently did not develop worsening outcomes. In addition, patients with miRNA-7151 expression and without worsening disease were characterized by higher 25(OH) vitamin D levels and lower prevalence of vitamin D deficiency. CONCLUSIONS: The expression of two novel miRNAs was reported for the first-time to be associated with a less severe COVID-19 form and to prospectively predict the occurrence of disease outcome. Furthermore, the association observed between vitamin D deficiency and lack of miRNA-7151 expression in COVID-19 patients with worse outcomes may support the hypothesis that the co-existence of these two conditions may have a strong negative prognostic role.
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Previous studies have shown a relationship between vitamin D and celiac disease (CD), however little evidence is available examining the direct effects of vitamin D on pathological features of this disease. In this study we evaluated the effect of oral administration of different doses of native vitamin D3 (cholecalciferol) in enteropathic mice. Female non-obese diabetic (NOD)/ShiLt.J mice were fed standard or gluten-free diet and administered gliadin (5 µg/kg) to induce a celiac pathology. Healthy control (gluten-free diet, without gliadin) and control for pathology (standard diet, with gliadin) were administered olive oil. All other experimental groups received gliadin and standard diet plus oral cholecalciferol (5, 10, 20, 50 and 130 µg/kg). Serum levels of 25(OH)D3, calcium and zonulin and expression of vitamin D receptor (VDR), CD3 and zonula occludens-1 (ZO-1) by immunohistochemistry as well as intestinal histological and histomorphometric analyses were undertaken. Although no difference in serum levels of 25(OH)D3, calcium or zonulin was observed in cholecalciferol-treated mice vs. healthy controls, a significant improvement in intestinal mucosa pathological features in mice administered cholecalciferol was observed by histological analysis. Villi length was also significantly increased by cholecalciferol in a dose-dependent manner. Immunohistochemical staining revealed increased expression of CD3 and ZO-1 in celiac mice compared to mice receiving high dose (130 µg/kg) cholecalciferol. These findings show the effect of oral cholecalciferol on signature features of CD in a mouse model of CD. Further dose-ranging studies to investigate the efficacy of cholecalciferol for the treatment of CD are warranted.