Association between Vitamin D Receptor Polymorphisms, Tight Junction Proteins and Clinical Features of Adult Patients with Atopic Dermatitis.

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.

Effect of oral cholecalciferol in a murine model of celiac disease: A dose ranging study.

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.

Cytochrome P-450 3A13 and endothelin jointly mediate ductus arteriosus constriction to oxygen in mice.

The fetal ductus arteriosus (DA) contracts to oxygen, and this feature, maturing through gestation, is considered important for its closure at birth. We have previously obtained evidence of the involvement of cytochrome P-450, possibly of the 3A subfamily (CYP3A), in oxygen sensing and have also identified endothelin (ET)-1 as the attendant effector for the contraction. Here, we examined comparatively wild-type (WT) and CYP3A-null (Cyp3a(-/-)) mice for direct validation of this concept. We found that the CYP3A subfamily is represented only by CYP3A13 in the WT DA. CYP3A13 was also detected in the DA by immunofluorescence microscopy, being primarily colocalized with the endoplasmic reticulum in both endothelial and muscle cells. However, a distinct signal was also evident in the plasma membrane. Isolated DAs from term WT animals developed a sustained contraction to oxygen with transient contractions superimposed. Conversely, no tonic response occurred in Cyp3a(-/-) DAs, whereas the phasic response persisted unabated. Oxygen did not contract the preterm WT DA but caused a full-fledged contraction after retinoic acid (RA) treatment. RA also promoted an oxygen contraction in the Cyp3a(-/-) DA. However, responses of RA-treated WT and Cyp3a(-/-) mice differed in that only the former abated with ET-1 suppression. This implies the existence of an alternative target for RA responsible for the oxygen-induced contraction in the absence of CYP3A13. In vivo, the DA was constricted in WT and Cyp3a(-/-) newborns, although with a tendency to be less narrowed in the mutant. We conclude that oxygen acts primarily through the complex CYP3A13 (sensor)/ET-1 (effector) and, in an accessory way, directly onto ET-1. However, even in the absence of CYP3A13, the DA may close postnatally thanks to the contribution of ET-1 and the likely involvement of compensating mechanism(s) identifiable with an alternative oxygen-sensing system and/or the withdrawal of relaxing influence(s) operating prenatally.

EDHF function in the ductus arteriosus: evidence against involvement of epoxyeicosatrienoic acids and 12S-hydroxyeicosatetraenoic acid.

We have previously shown (Ref. 2) that endothelium-derived hyperpolarizing factor (EDHF) becomes functional in the fetal ductus arteriosus on removal of nitric oxide and carbon monoxide. From this, it was proposed that EDHF originates from a cytochrome P-450 (CYP450)-catalyzed reaction being inhibited by the two agents. Here, we have examined in the mouse ductus whether EDHF can be identified as an arachidonic acid product of a CYP450 epoxygenase and allied pathways. We did not detect transcripts of the mouse CYP2C subfamily in vessel, while CYP2J subfamily transcripts were expressed with CYP2J6 and CYP2J9. These CYP2J hemoproteins were also detected in the ductus by immunofluorescence microscopy, being colocalized with the endoplasmic reticulum in both endothelial and muscle cells. Distinct CYP450 transcripts were also detected and were responsible for omega-hydroxylation (CYP4A31) and 12R-hydroxylation (CYP4B1). Mass spectrometric analysis showed formation of epoxyeicosatrienoic acids (EETs) in the intact ductus, with 11,12- and 14,15-EETs being more prominent than 5,6- and 8,9-EETs. However, their yield did not increase with nitric oxide/carbon monoxide suppression, nor did it abate with endothelium removal. No evidence was obtained for formation of 12R-hydroxyeicosatrienoic acid and omega-hydroxylation products. 2S-hydroxyeicosatetraenoic acid was instead detected, and, contrary to data implicating this compound as an alternative EDHF, its suppression with baicalein did not modify the EDHF-mediated relaxation to bradykinin. We conclude that none of the more common CYP450-linked arachidonic acid metabolites appears to qualify as EDHF in mouse ductus. We speculate that some novel eicosanoid or a totally unrelated compound requiring CYP450 for its synthesis accounts for EDHF in this vessel.

Lisosan G, a powder of grain, does not interfere with the drug metabolizing enzymes and has a protective role on carbon tetrachloride-induced hepatotoxicity.

Lisosan G is a powder of grain registered as an alimentary integrator. The treatment of rats for 4 days with 0.5 g Lisosan G/kg had no effect on various drug metabolizing enzymes. Experiments in vitro showed that Lisosan G had radical scavenger activity. A confirmation of the antioxidative property of Lisosan G was also confirmed when it was administered in vivo to carbon tetrachloride (CCl(4))-intoxicated rats. The toxicity caused by CCl(4)-treatment of rats was restored to the control levels when the rats were given Lisosan G for 4 days before CCl(4). Lisosan G thus does not interfere with drug metabolizing system but has antioxidant properties and protects against CCl(4)-induced hepatotoxicity.