Vitamin D deficiency negatively affects both the intestinal epithelial integrity and bone metabolism in children with Celiac disease.

BACKGROUND AND AIM: We aim to evaluate serum vitamin D levels, vitamin D receptor (VDR) expression in the intestinal epithelium, and their relation with epithelial barrier proteins and bone metabolism in children with Celiac disease (CD).

METHODS

Immunostaining for VDR, Claudin-2 and E-cadherin was performed in duodenal samples of the patients with CD and controls. H-score [∑Pi(I+1)] where I is the intensity score and Pi is the corresponding percentage of stained cells was calculated for each samples. The clinic, laboratory and histopathological findings were compared between patients and controls.

RESULTS

Thirty-six patients with CD and age and sex matched 36 controls were enrolled. 25-OH vitamin D levels were significantly lower in the patient group compared to the control group. The mean bone mineral density (BMD) value was significantly lower in patients with vitamin D deficiency compared to patients with normal vitamin D level. H-scores for both VDR and Claudin-2 were significantly lower in patient group when compared to the control group. H-scores for VDR, Claudin-2 and E-cadherin were significantly lower in patients with vitamin D deficiency compared to patients with normal vitamin D level. There were positive correlations between 25-OH vitamin D level and H-scores for VDR, E-cadherin and Claudin-2 in patient group.

CONCLUSIONS

Our findings showed that vitamin D deficiency is common among children with CD. Expression of VDR and epithelial barrier proteins Claudin-2 and E-cadherin which have important roles in paracellular pathway, was decreased in children with CD in correlation with histological findings of disease severity. Furthermore, deficiency of vitamin D was related to decreased expression of VDR and epithelial barrier proteins E-cadherin and Claudin-2. These findings indicate that paracellular pathway structures responsible for calcium absorption are disturbed in CD which is aggravated by vitamin D deficiency.