Immunomodulatory effects of 1,25-dihydroxyvitamin D3 on TH1/TH2 cytokines in inflammatory bowel disease: an in vitro study

Effects of immunosuppression-associated gga-miR-146a-5p on immune regulation in chicken macrophages by targeting the IRKA2 gene

Stress-induced immunosuppression (SIIS) is one of the common problems in intensive poultry production, which brings enormous economic losses to the poultry industry. Accumulating evidence has shown that microRNAs (miRNAs) were important regulators of gene expression in the immune system. However, the miRNA-mediated molecular mechanisms underlying SIIS in chickens are still poorly understood. This study aimed to investigate the biological functions and regulatory mechanism of miRNAs in chicken SIIS. A stress-induced immunosuppression model was successfully established via daily injection of dexamethasone and analyzed miRNA expression in spleen. Seventy-four differentially expressed miRNAs (DEMs) was identified, and 229 target genes of the DEMs were predicted. Functional enrichment analysis the target genes revealed pathways related to immunity, such as MAPK signaling pathway and FoxO signaling pathway. The candidate miRNA, gga-miR-146a-5p, was found to be significantly downregulated in the Dex-induced chicken spleen, and we found that Dex stimulation significantly inhibited the expression of gga-miR-146a-5p in Chicken macrophages (HD11). Flow cytometry, 5-ethynyl-2'-deoxyuridine (EdU), cell counting kit-8 (CCK-8) and other assays indicated that gga-miR-146a-5p can promote the proliferation and inhibit apoptosis of HD11 cells. A dual-luciferase reporter assay suggested that the Interleukin 1 receptor associated kinase 2 (IRAK2) gene, which encoded a transcriptional factor, was a direct target of gga-miR-146a-5p, gga-miR-146a-5p suppressed the post-transcriptional activity of IRAK2. These findings not only improve our understanding of the specific functions of miRNAs in avian stress but also provide potential targets for genetic improvement of stress resistance in poultry.

Identification and immunoinfiltration analysis of key genes in ulcerative colitis using WGCNA

Objective

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease characterized by an unclear pathogenesis. This study aims to screen out key genes related to UC pathogenesis.

Methods

Bioinformatics analysis was conducted for screening key genes linked to UC pathogenesis, and the expression of the screened key genes was verified by establishing a UC mouse model.

Results

Through bioinformatics analysis, five key genes were obtained. Subsequent infiltration analysis revealed seven significantly different immune cell types between the UC and general samples. Additionally, animal experiment results illustrated markedly decreased body weight, visible colonic shortening and damage, along with a significant increase in the DAI score of the DSS-induced mice in the UC group in comparison with the NC group. In addition, H&E staining results demonstrated histological changes including marked inflammatory cell infiltration, loss of crypts, and epithelial destruction in the colon mucosa epithelium. qRT-PCR analysis indicated a down-regulation of ABCG2 and an up-regulation of IL1RN, REG4, SERPINB5 and TRIM29 in the UC mouse model. Notably, this observed trend showed a significant dependence on the concentration of DSS, with the mouse model of UC induced by 7% DSS demonstrating a more severe disease state compared to that induced by 5% DSS.

Conclusion

ABCG2, IL1RN, REG4, SERPINB5 and TRIM29 were screened out as key genes related to UC by bioinformatics analysis. The expression of ABCG2 was down-regulated, and that of IL1RN, REG4, SERPINB5 and TRIM29 were up-regulated in UC mice as revealed by animal experiments.

The role of vitamin D receptor gene polymorphism in the development of necrotizing enterocolitis

BACKGROUND

Vitamin D and its receptor (VDR) effects on the gastrointestinal system are among its most critical multisystemic effects.

METHODS

This study aimed to reveal that VDR gene polymorphisms may constitute a risk factor for necrotizing enterocolitis (NEC). VDR Fok1-Bsm1-Apa single-nucleotide polymorphisms were analyzed in the NEC group (n = 74) and the control group (n = 147). Among 1112 babies at and below 36 weeks of gestational age who were hospitalized between January 2013 and December 2016 with a diagnosis of prematurity, 74 of a total of 148 patients who developed NEC during follow-up (NEC group) were included in the study. When NEC was diagnosed according to clinical and radiological findings and staged using Modified Bell criteria, 9 (12.1%) of 74 babies were stage 1A, 13 (17.5%) stage 1B, and 5 (6.7%) stage 2A, 33 (44.5%) stage 2B, 7 (9.4%) stage 3A, 7 (9.4%) stage 3B. Of 964 babies who did not develop NEC during follow-up, 147 were included as the control group in the study. Genotyping of VDR polymorphisms was assayed by real-time PCR. From 221 premature babies in the NEC and control groups, 2 ml peripheral blood was taken appropriately and meticulously into an EDTA tube. DNA was isolated from these blood samples. DNA amplification was performed using a thermal cycler (Applied Biosystems GeneAmp PCR System 9600).

RESULTS

When the two groups were compared in terms of the prevalence of VDR Fok1 C/T genotype, it was found that TT genotype increased the risk of NEC by 2.697 times, and there was a significant relationship between TT genotype and the risk of NEC (p = 0.041). Multivariable logistic regression analysis was performed in terms of gestational age, birth weight, VDR gene polymorphism data between NEC and the control group. According to the analysis results, TT polymorphism, increased the risk of disease 4.5 times (p = 0.033).

CONCLUSION

Fok 1 C > T polymorphism in the VDR gene plays a role in the development of NEC. Identifying the risk groups by detecting gene polymorphisms that cause increased susceptibility to NEC may assist in the follow-up of these patients and in making early treatment decisions for them.

IMPACT

In this study examining the non-bone effects of the genetic differences in vitamin D metabolism in premature babies, Fok 1 polymorphism has been observed to be an essential risk factor for NEC. This is the first study in our country that has investigated the relationship between VDR gene polymorphism and necrotizing enterocolitis among the Turkish population. Identifying the risk groups by detecting gene polymorphisms that cause increased susceptibility to NEC may assist in the monitoring of these patients and in making early treatment decisions for them.

The Role of Vitamin D in Immune System and Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a nonspecific inflammatory disease that includes ulcerative colitis (UC) and Crohn’s disease (CD). The pathogenesis of IBD is not fully understood but is most reported associated with immune dysregulation, dysbacteriosis, genetic susceptibility, and environmental risk factors. Vitamin D is an essential nutrient for the human body, and it not only regulates bone metabolism but also the immune system, the intestinal microbiota and barrier. Vitamin D insufficiency is common in IBD patients, and the abnormal low levels of vitamin D are highly correlated with disease activity, treatment response, and risk of relapse of IBD. Accumulating evidence supports the protective role of vitamin D in IBD through regulating the adaptive and innate immunity, maintaining the intestinal barrier and balancing the gut microbiota. This report aims to provide a broad overview of the role vitamin D in the immune system, especially in the pathogenesis and treatment of IBD, and its possible role in predicting relapse.

Transcriptional Profiling of the Small Intestine and the Colon Reveals Modulation of Gut Infection with Citrobacter rodentium According to the Vitamin A Status

Vitamin A (VA) deficiency and diarrheal diseases are both serious public health issues worldwide. VA deficiency is associated with impaired intestinal barrier function and increased risk of mucosal infection-related mortality. The bioactive form of VA, retinoic acid, is a well-known regulator of mucosal integrity. Using Citrobacter rodentium-infected mice as a model for diarrheal diseases in humans, previous studies showed that VA-deficient (VAD) mice failed to clear C. rodentium as compared to their VA-sufficient (VAS) counterparts. However, the distinct intestinal gene responses that are dependent on the host’s VA status still need to be discovered. The mRNAs extracted from the small intestine (SI) and the colon were sequenced and analyzed on three levels: differential gene expression, enrichment, and co-expression. C. rodentium infection interacted differentially with VA status to alter colon gene expression. Novel functional categories downregulated by this pathogen were identified, highlighted by genes related to the metabolism of VA, vitamin D, and ion transport, including improper upregulation of Cl⁻ secretion and disrupted HCO₃⁻ metabolism. Our results suggest that derangement of micronutrient metabolism and ion transport, together with the compromised immune responses in VAD hosts, may be responsible for the higher mortality to C. rodentium under conditions of inadequate VA.

Association of vitamin D deficiency with COVID-19 infection severity: Systematic review and meta-analysis

BACKGROUND

We sought to evaluate the association between vitamin D deficiency and the severity of coronavirus disease 2019 (COVID-19) infection.

METHODS

Multiple databases from 1 January 2019 to 3 December 2020 were searched for observational studies evaluating the association between vitamin D deficiency and severity of COVID-19 infection. Independent reviewers selected studies and extracted data for the review. The main outcomes of interest were mortality, hospital admission, length of hospital stay and intensive care unit admission.

RESULTS

Seventeen observational studies with 2756 patients were included in the analyses. Vitamin D deficiency was associated with significantly higher mortality (odds ratio [OR]: 2.47, 95% confidence interval [CI]: 1.50-4.05; 12 studies; hazard ratio [HR]: 4.11, 95% CI: 2.40-7.04; 3 studies), higher rates of hospital admissions (OR: 2.18, 95% CI: 1.48-3.21; 3 studies) and longer hospital stays (0.52 days; 95% CI: 0.25-0.80; 2 studies) as compared to nonvitamin D deficient status. Subgroup analyses based on different cut-offs for defining vitamin D deficiency, study geographic locations and latitude also showed similar trends.

CONCLUSIONS

Vitamin D deficiency is associated with greater severity of COVID-19 infection. Further studies are warranted to determine if vitamin D supplementation can decrease the severity of COVID-19.

Relevance of Biotin Deficiency in Patients with Inflammatory Bowel Disease and Utility of Serum 3 Hydroxyisovaleryl Carnitine as a Practical Everyday Marker

Background: Biotin, a water-soluble B vitamin, has demonstrable anti-inflammatory properties. A biotin-deficient diet induced a colitis-like phenotype in mice, alleviable by biotin substitution. Mice with dextran sulfate sodium (DSS)-induced colitis showed biotin deficiency and diminished levels of sodium-dependent multivitamin transporter, a protein involved in biotin absorption. Biotin substitution induced remission by reducing activation of NF-κB, a transcription factor involved in intestinal permeability and inflammatory bowel disease (IBD). We investigated for the first time a possible clinical role of biotin status in IBD. Methods: In a comparative, retrospective, cross-sectional study, serum samples of 138 patients with IBD (67 female; 72 Crohn’s disease (CD), 66 ulcerative colitis (UC)) aged 18–65 years and with a mean age (±SD) of 42.5 ± 14.3 years as well as 80 healthy blood donors (40 female; 40.0 ± 10.0 years; range 20–60 years) were analyzed. Inflammation was defined as hsCRP ≥5 mg/L, and to determine biotin status, serum 3-hydroxyisovaleryl carnitine (3HIVc) levels were measured by LC-MS/MS. Results: A total of 138 patients with IBD (67f; 72CD/66 UC; 42.5 ± 14.3 years) were enrolled: 83/138 had inflammation. Mean serum 3HIVc levels were significantly higher in IBD patients but unaffected by inflammation. Biotin deficiency (95th percentile of controls: >30 nmol/L 3HIVc) was significantly more common in IBD patients versus controls. Conclusion: High serum 3HIVc levels and biotin deficiency were associated with IBD but not inflammatory activity or disease type. Our findings suggest biotin may play a role as cause or effect in IBD pathogenesis. Routine assessment and supplementation of biotin may ameliorate IBD and support intestinal integrity.

Vitamin D3 and its hydroxyderivatives as promising drugs against COVID-19: a computational study

The epidemiologic correlation between the poor prognosis of SARS-CoV-2 infection and vitamin D deficiency has been observed worldwide, however, their molecular mechanisms are not fully understood. In this study, we used combined molecular docking, molecular dynamics simulations and binding free energy analyses to investigate the potentials of vitamin D3 and its hydroxyderivatives as TMPRSS2 inhibitor and to inhibit the SARS-CoV-2 receptor binding domain (RBD) binding to angiotensin-converting enzyme 2 (ACE2), as well as to unveil molecular and structural basis of 1,25(OH)₂D3 capability to inhibit ACE2 and SARS-CoV-2 RBD interactions. The results show that vitamin D3 and its hydroxyderivatives are favorable to bind active site of TMPRSS2 and the binding site(s) between ACE2 and SARS-CoV2-RBD, which indicate that vitamin D3 and its biologically active hydroxyderivatives can serve as TMPRSS2 inhibitor and can inhibit ACE2 binding of SARS-CoV-2 RBD to prevent SARS-CoV-2 entry. Interaction of 1,25(OH)₂D3 with SARS-CoV-2 RBD and ACE2 resulted in the conformation and dynamical motion changes of the binding surfaces between SARS-CoV-2 RBD and ACE2 to interrupt the binding of SARS-CoV-2 RBD with ACE2. The interaction of 1,25(OH)₂D3 with TMPRSS2 also caused the conformational and dynamical motion changes of TMPRSS2, which could affect TMPRSS2 to prime SARS-CoV-2 spike proteins. Our results propose that vitamin D3 and its biologically active hydroxyderivatives are promising drugs or adjuvants in the treatment of COVID-19. Communicated by Ramaswamy H. Sarma.

Insufficient evidence for vitamin D use in COVID-19: A rapid systematic review

BACKGROUND

Vitamin D deficiency has been linked to the increased severity of numerous viral infections.

OBJECTIVE

To assess whether vitamin D supplementation is safe and effective for the treatment of COVID-19.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, LILACS and LOVE for randomised controlled trials (RCTs) published up to 2 March evaluating the effects of vitamin D for the treatment of coronavirus disease (COVID-19). Two authors selected the studies and analysed the data evidence following Cochrane Recommendations.

RESULTS

We included three RCTs with a total of 385 participants. We found low certainty evidence indicating that hospitalised patients under calcifediol plus standard care (SC) treatment seem to present a significantly lower risk of being admitted to ICU but no difference in mortality. We found low to very low certainty evidence that the improvement in fibrinogen levels is slightly greater in mildly symptomatic or asymptomatic patients with COVID-19 that used cholecalciferol plus SC than in those treated with placebo plus SC (mean difference), and the patients who used cholecalciferol plus SC achieved more SARS-CoV-2 negativity, but not on d-dimer, c-reactive protein (CRP) or procalcitonin compared with the patients in the placebo plus SC group. We also found low to moderate certainty evidence that a single high dose of vitamin D does not seem to be effective for reducing mortality, length of hospital stay, ICU admissions and d-dimer or CRP levels when used in patients with moderate to severe COVID-19.

CONCLUSIONS

As a practical implication, the use of vitamin D associated with SC seems to provide some benefit to patients with COVID-19. However, the evidence is currently insufficient to support the routine use of vitamin D for the management of COVID-19, as its effectiveness seems to depend on the dosage, on the baseline vitamin D levels, and on the degree of COVID-19 severity.

ROLE OF VITAMIN D SUPPLEMENTATION IN THE PREVENTION OF INFECTION AND SEVERE COURSE IN COVID-19: TESTING THE HYPOTHESIS

The coronavirus disease 2019 (COVID-19) pandemic has disrupted the normal activities of various settings, including clinics, laboratories, and libraries. As the world deals with the fast-mutating causative virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), apart from the search for the best vaccine candidate, efforts towards repurposing existing molecules to save lives must continue. Considerable interest has centered around the implications of vitamin D deficiency and its supplementation on the outcomes in patients with COVID-19. We hypothesize that vitamin D supplementation has the potential to confer protection against SARS-CoV-2 infection and a severe COVID-19 course. Various animal, human observational as well as interventional studies have shown a protective role of vitamin D in COVID-19. More robustly designed studies where vitamin D is supplemented prophylactically and administered to those already infected are needed to determine the precise contribution of this supplementation in preventing SARS-CoV-2 infection and modifying the course of COVID-19.

Vitamin D in Children With Inflammatory Bowel Disease: A Randomized Controlled Clinical Trial

BACKGROUND

Vitamin D has anti-inflammatory and immune regulatory functions.

GOALS

The authors investigated the effect of vitamin D supplementation in children with inflammatory bowel disease (IBD) and hypovitaminosis D on disease activity, quality of life (QOL), inflammatory markers, and cytokines.

STUDY

This randomized double-blinded controlled clinical trial included 120 children with IBD and hypovitaminosis D; 22 of them were excluded later. Patients were randomized to receive either oral vitamin D3 in a dose of 2000 IU/day or placebo for 6 months. The primary outcome was to evaluate the effect of vitamin D supplementation on the IBD activity score. The secondary outcomes were to assess the QOL, inflammatory markers, cytokines, the safety of vitamin D, and to correlate serum vitamin D level with various clinical and laboratory variables.

RESULTS

Vitamin D supplementation significantly decreased the IBD activity score in the vitamin D group compared with the placebo group. Moreover, QOL significantly improved after vitamin D supplementation. Inflammatory markers, for example, erythrocyte sedimentation rate, C-reactive protein, and fecal calprotectin and interleukin-2 IL-12, IL-17, IL-23, and tumor necrosis factor-alpha significantly decreased in the vitamin D group. However, IL-10 significantly increased after vitamin D supplementation. Vitamin D was significantly inversely correlated with the activity score, QOL score, levels of all inflammatory markers, the frequency of hospitalization, and emergency department visits.

CONCLUSION

Vitamin D supplementation may have a beneficial effect in children with IBD.

High-Dose Vitamin D Does Not Prevent Postoperative Recurrence of Crohn's Disease in a Randomized Placebo-Controlled Trial

BACKGROUND & AIMS

Vitamin D deficiency is common in Crohn's disease (CD). High-dose vitamin D had anti-inflammatory effects in preclinical studies and trials of patients with CD. We performed a randomized trial to determine whether high-dose vitamin D prevents postoperative recurrence of CD after ileocolonic resection.

METHODS

Patients with CD after ileocolonic resection with ileocolonic anastomosis were assigned randomly to groups given weekly 25,000 IU oral vitamin D (n = 72) or placebo (n = 71) for 26 weeks, at 17 hospitals in The Netherlands and Belgium, from February 2014 through June 2017. Patients were assessed at baseline and at weeks 2, 6, 12, and 26 for laboratory and clinical parameters, and underwent ileocolonoscopy at 26 weeks. The primary end point was endoscopic recurrence (modified Rutgeerts score, ≥i2b, as assessed by blinded readers) at 26 weeks. Secondary end points included clinical recurrence (Crohn's disease activity index, ≥220), quality of life (measured by the 36-Item Short Form Health Survey, Inflammatory Bowel Disease Questionnaire, and EuroQol, a 5-dimension questionnaire), and outcomes associated with the baseline serum concentration of vitamin D.

RESULTS

In the vitamin D group, serum levels of 25-hydroxy vitamin D increased from a median of 42 nmol/L at baseline to 81 nmol/L at week 26 (P < .00001), whereas levels did not change significantly in the placebo group and remained unchanged at 43 nmol/L. In the intention-to-treat analysis, the proportion of patients with endoscopic recurrence at 26 weeks did not differ significantly between the vitamin D vs the placebo group (58% vs 66%; P = .37). The cumulative rate of clinical recurrence did not differ significantly between the groups (18.1% in the vitamin D group vs 18.3% in the placebo group; P = .91). Quality of life improved slightly over time in both groups, but did not differ significantly between groups (P = .07). There were few adverse events in either group.

CONCLUSIONS

High-dose vitamin D, compared with placebo, did not reduce the incidence of postoperative endoscopic or clinical recurrence of CD in patients who underwent ileocolonic resection with ileocolonic anastomosis. ClinicalTrials.gov no: NCT02010762.

Immunomodulatory effect of in vitro calcitriol in fit and frail elderly

INTRODUCTION

Effect of calcitriol on PBMCs of healthy adults have been well studied but not much is known about its effect on the PBMCs of elderly patients with various degree of frailty syndrome and immune senescence. This study was aimed to assess the effect of in vitro calcitriol immunomodulatory effect on IL-6, IL-10 and IFN-γ in elderly patients who were fit, pre-frail and frail to see which group of patients might get the most benefit of calcitriol.

METHODS

This study was an experimental study on the PBMCs of 24 elderly people, of which 8 subjects each were in fit, pre-frail and frail categories based on the Cardiovascular Health Study criteria. IL-6, IL-10, and IFN-γ were examined by ELISA, before and after administration of lipopolysaccharide and 100 pg/mL calcitriol into PBMC cultures in vitro.

RESULT

The mean serum vitamin D level was 26.2 (2.4) ng/ml. Vitamin D level is decreasing along with worsening of frailty status. After LPS induction, calcitriol did not reduce IL-6 and IFN-γ in all the groups. Calcitriol increased IL-10 in all groups, with the most observed change in the pre-frail group.

CONCLUSION

In vitro administration of calcitriol showed anti-inflammatory potential by increasing IL-10 mainly in pre-frail subjects.

Vitamin D can prevent COVID-19 infection-induced multiple organ damage

Vitamin D is an immunomodulator hormone with an anti-inflammatory and antimicrobial effect with a high safety profile. A lot of COVID-19 infected patients develop acute respiratory distress syndrome (ARDS), which may lead to multiple organ damage. These symptoms are associated with a cytokine storm syndrome. The aim of this letter is to note the 5 crucial points that vitamin D could have protective and therapeutic effects against COVID-19. For that reason, COVID-19 infection-induced multiple organ damage might be prevented by vitamin D.

Transcriptomic Analysis of Spleen Revealed Mechanism of Dexamethasone-Induced Immune Suppression in Chicks

Stress-induced immunosuppression is a common problem in the poultry industry, but the specific mechanism of its effect on the immune function of chicken has not been clarified. In this study, 7-day-old Gushi cocks were selected as subjects, and a stress-induced immunosuppression model was successfully established via daily injection of 2.0 mg/kg (body weight) dexamethasone. We characterized the spleen transcriptome in the control (B_S) and model (D_S) groups, and 515 significant differentially expressed genes (SDEGs) (Fragments Per Kilobase of transcript sequence per Millions base pairs sequenced (FPKM) > 1, adjusted p-value (padj) < 0.05 and Fold change (|FC|) ≥ 2) were identified. The cytokine-cytokine receptor interaction signaling pathway was identified as being highly activated during stress-induced immunosuppression, including the following SDEGs-CXCL13L2, CSF3R, CSF2RB, CCR9, CCR10, IL1R1, IL8L1, IL8L2, GHR, KIT, OSMR, TNFRSF13B, TNFSF13B, and TGFBR2L. At the same time, immune-related SDEGs including CCR9, CCR10, DMB1, TNFRSF13B, TNFRSF13C and TNFSF13B were significantly enriched in the intestinal immune network for the IgA production signaling pathway. The SDEG protein-protein interaction module analysis showed that CXCR5, CCR8L, CCR9, CCR10, IL8L2, IL8L1, TNFSF13B, TNFRSF13B and TNFRSF13C may play an important role in stress-induced immunosuppression. These findings provide a background for further research on stress-induced immunosuppression. Thus, we can better understand the molecular genetic mechanism of chicken stress-induced immunosuppression.

Single High-dose Vitamin D3 Supplementation in Pediatric Patients With Inflammatory Bowel Disease and Hypovitaminosis D

OBJECTIVES

The primary aim was to determine the effectiveness of a single high-dose of oral vitamin D3 (stoss therapy) in children with inflammatory bowel disease (IBD) and hypovitaminosis D. Our secondary aim was to examine the safety of stoss therapy.

METHODS

We conducted a randomized, prospective study of 44 patients, ages 6 to 21 years, with IBD and 25-hydroxyvitamin D (25-OHD) concentrations <30 ng/mL. Patients were randomized to receive 50,000 IU of vitamin D3 once weekly for 6 weeks (standard of care, SOC group) or 300,000 IU once (stoss group). Serum 25-OHD levels were obtained at baseline, 4 and 12 weeks. Safety monitoring labs were performed at week 4.

RESULTS

Thirty-nine of 44 enrolled patients (19 stoss, 20 SOC) completed the study. Baseline vitamin D levels were not significantly different between the groups. Stoss therapy resulted in a substantial rise in 25-OHD levels at week 4, equivalent to the weekly regimen (53.6 ± 17.3 vs 54.6 ± 17.5 ng/mL). At week 12, serum 25-OHD levels decreased in both groups, significantly lower in the stoss group, but remained close to 30 ng/mL (29.8 ± 7.1 vs 40.4 ± 11.9 ng/mL, P = 0.04). A significant interaction with treatment group over time was observed (P = 0.0003). At the week-4 time point, all patients who received stoss therapy had normal serum calcium and PTH levels. Eighty percentage of patients preferred stoss therapy to the weekly regimen.

CONCLUSIONS

Stoss therapy was safe and effective in raising 25-OHD in children with IBD commensurate to that of the weekly regimen.

Measuring Vitamin D Status in Chronic Inflammatory Disorders: How does Chronic Inflammation Affect the Reliability of Vitamin D Metabolites in Patients with IBD?

Evidence gained from recent studies has generated increasing interest in the role of vitamin D in extraskeletal functions such as inflammation and immunoregulation. Although vitamin D deficiency has been implicated in the pathophysiology of inflammatory diseases including inflammatory bowel disease (IBD), evidence as to whether vitamin D supplementation may cure or prevent chronic disease is inconsistent. Since 25OH-vitamin D (25OHD) has been suggested to be an acute-phase protein, its utility as a vitamin D status marker is therefore questionable. In this study, possible interactions of vitamin D and inflammation were studied in 188 patients with IBD, with high-sensitivity C-reactive protein (hsCRP) levels ≥ 5 mg/dL and/or fecal calprotectin ≥ 250 µg/g defined as biochemical evidence of inflammatory activity. Levels of 25OHD and vitamin D-binding protein (VDBP) were determined by ELISA, and 1,25-dihydroxyvitamin D (1,25OHD) and dihydroxycholecalciferol (24,25OHD) by LC-MS/MS. Free and bioavailable vitamin D levels were calculated with the validated formula of Bikle. Serum 1,25OH2D and vitamin D binding protein (VDBP) levels were shown to differ between the inflammatory and noninflammatory groups: patients with inflammatory disease activity had significantly higher serum concentrations of 1,25OH2D (35.0 (16.4-67.3) vs. 18.5 (1.2-51.0) pg/mL, p < 0.001) and VDBP (351.2 (252.2-530.6) vs. 330.8 (183.5-560.3) mg/dL, p < 0.05) than patients without active inflammation. Serum 24,25OH2D levels were negatively correlated with erythrocyte sedimentation rate (ESR) (-0.155, p = 0.049) while concentrations of serum 1,25OH2D correlated positively with hsCRP (0.157, p = 0.036). Correlations with serum VDBP levels were found for ESR (0.150, p = 0.049), transferrin (0.160, p = 0.037) and hsCRP (0.261, p < 0.001). Levels of serum free and bioavailable 25OHD showed a negative correlation with ESR (-0.165, p = 0.031, -0.205, p < 0.001, respectively) and hsCRP (-0.164, p = 0.032, -0.208, p < 0.001 respectively), and a moderate negative correlation with fecal calprotectin (-0.377, p = 0.028, -0.409, p < 0.016, respectively). Serum total 25OHD concentration was the only vitamin D parameter found to have no specific correlation with any of the inflammatory markers. According to these results, the traditional parameter, total 25OHD, still appears to be the best marker of vitamin D status in patients with inflammatory bowel disease regardless of the presence of inflammation.

Effect of single-dose injection of vitamin D on immune cytokines in ulcerative colitis patients: a randomized placebo-controlled trial

Ulcerative colitis (UC) is a chronic recurrent inflammation of the colon. It has been proposed that the UC pathogenesis may be related to vitamin D deficiency and/or vitamin D administration in UC patients may have an ameliorating effect on the intestinal inflammation. The aim of this study was to assess the effect of vitamin D on the serum levels of immune cytokines in UC patients. In this double-blind randomized controlled trial, 90 mild-to-moderate UC patients were assigned to get either a single muscular injection of 7.5 mg vitamin D3 or 1 mL normal saline as placebo. Three months later serum levels of IL-4, IL-10, IL-12p70, IFN-γ, and TNF-α were measured. Two group variables were compared using independent t-test and analysis of covariance (ANCOVA). There was a significant increase in vitamin D only in the vitamin D group. Compared to placebo, vitamin D had significant decreasing effects on serum TNF-α, IFN-γ, and IL12p70 levels, but it had no significant effect on serum levels of IL4 and IL10. Vitamin D seems to inhibit Th1 immune responses and have no effect on Th2 responses. The findings of this study support several in vitro studies, which suggest a therapeutic immunomodulatory potential of vitamin D.

Vitamin D deficiency during pregnancy affects the function of Th1/Th2 cells and methylation of IFN-γ gene in offspring rats

The effects of maternal vitamin D status on offspring's Th1/Th2 cell function and the related mechanisms have not been reported. In this study, we established the rat model of vitamin D deficiency during pregnancy. 48 female Sprague-Dawley rats (8 weeks old) were randomly assigned to three groups (n = 16/group): control group (fed with standard AIN-93 G diet until parturition), vitamin D deficiency group (VDD group, fed with vitamin D deficient diet until parturition) and vitamin D supplementation group (VDS group, fed with vitamin D deficient diet prior to mating and with standard AIN-93 G diet during pregnancy). At 4 weeks of age, the ratio of T helper type 1/ T helper type 2 (Th1/Th2) cells and the levels of Th1/Th2 cytokines (IFN-γ, IL-4, IL-5, IL-6, IL-10 and IL-13) in offspring rats were determined by Flow Cytometry and Meso Scale Discovery, respectively. Furthermore, DNA methyltransferase (DNMT) activity as well as the methylation levels of IFN-γ and IL-4 genes were measured. As a result, rats in the VDD group showed a significant decrease in Th1/Th2 ratio and IFN-γ level and an increase in IL-4 level. Additionally, up-regulated DNMT activity and increased methylation rate of IFN-γ gene was shown in VDD offspring rats. Supplementation with vitamin D during pregnancy reversed the above abnormalities. In conclusion, maternal vitamin D deficiency affected the function of Th1/Th2 cells and methylation of IFN-γ gene in offspring rats. Meanwhile, maternal vitamin D deficiency had the potential to regulate DNMT activity, which may determine the status of methylation.

Vitamin D aggravates breast cancer by inducing immunosuppression in the tumor bearing mouse

The aim of this approach is to test the effects and related mechanism of vitamin D (VD) treatment on the outcomes of breast cancer. BALB/c mice were injected with 4T1 breast cancer cell suspension. The test group was treated with VD reagent. The survival and tumor size of mice were observed. The proliferation of 4T1 in vitro was detected by MTS analysis. The changes of immune parameters and microenvironment in mice were evaluated by flow cytometry and real-time RT-PCR. Our results demonstrate that VD administration caused a decline in survival time and raising the volume of tumor, the decreasing numbers of CD3⁺CD4⁺ T, CD3⁺CD8⁺ T and CD4⁺T-bet⁺IFN-γ⁺ Th1 cells and transcriptions of T-bet and IFN-γ, an increasing number of myeloid-derived suppressor cells and transcription of TGF-β. Our data suggest that the routine clinical application of any strategies targeting VD status for breast cancer therapy is deserved serious consideration.

Regulation of Immune Function by Vitamin D and Its Use in Diseases of Immunity

Evidence exists for a role for vitamin D and its active metabolites in modulating immune functions. In animal models, vitamin D deficiency is associated with a higher risk for autoimmunity in genetically predisposed subjects and increases in susceptibility to infections. In addition, high-dose vitamin D can improve immune health, prevent autoimmunity, and improve defense against infections. In humans, evidence exists on associations between vitamin D deficiency and impaired immune function, leading to autoimmunity in genetically predisposed people and increased risk for infections; data on therapeutic immune effects of vitamin D supplementation when vitamin D levels are already sufficient are lacking.

Immunoregulation of Inflammatory and Inhibitory Cytokines by Vitamin D3 in Patients with Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is a group of idiopathic, chronic and relapsing inflammatory conditions of the gastrointestinal tract, caused by an aberrant and exaggerated immunological response in the gut. Supplementation of vitamin D3 in patients with IBD exerts both direct and indirect regulatory roles on the naïve T cells, thereby maintaining a balance between inflammatory and inhibitory cytokines. The direct actions of vitamin D3 on naïve T cells result in the proliferation of more regulatory T cells and inhibitory cytokines such as IL-4, IL-10 and IL-5. The binding of vitamin D to dendritic cells (DCs) through vitamin D receptors inhibits the action of IL-12 on DCs, resulting in the downregulation of Th1 and Th17. On the other hand, this interaction favours Th2 and Treg upregulation and facilitates the maintenance of immune homoeostasis between inflammatory and inhibitory cytokines which is essentially significant in the management of patients with IBD. The aim of this review was to explore the current and mounting scientific evidence on the roles of vitamin D3 in immunoregulation of inflammatory and inhibitory cytokines in patients with IBDs. An extensive literature search was conducted using keywords such as Vitamin D3*, IBD*, inflammatory cytokines*, inhibitory cytokines*, naïve-T-cells* and antigen presenting cells* through PubMed, SCOPUS and MEDLINE search engines. The results of the accumulated bodies of research that have been conducted demonstrate that vitamin D3 plays a major role not only in the immunoregulation of cytokines involved in the pathogenesis of IBDs but also in many other inflammatory disorders.

Maternal/neonatal vitamin D deficiency: a new risk factor for necrotizing enterocolitis in preterm infants?

OBJECTIVE

The objective of the study was to investigate the possible association between maternal/neonatal 25-hydroxy vitamin D (25-OHD) levels and development of necrotizing enterocolitis (NEC).

STUDY DESIGN

One hundred and forty-five preterm infants ⩽36 weeks of gestation were enrolled. 25-OHD levels were determined in maternal/neonatal blood samples that were obtained at the time of admission to the neonatal intensive care unit.

RESULTS

Of the 145 enrolled patients, 26 (18%) developed NEC. Maternal/neonatal 25-OHD levels in the NEC group were significantly lower than those of the no-NEC group (P=0.001 and 0.004, respectively). In univariate logistic regression analysis, both maternal/neonatal vitamin D levels were a significant predictor of NEC (odds ratio (OR): 0.92 and 0.89; P<0.001 and P<0.005, respectively). However, multivariate logistic regression analysis revealed that only maternal vitamin D level was a significant predictor of NEC (OR: 0.86, P<0.0009).

CONCLUSION

This is the first study to propose a possible association between maternal/neonatal 25-OHD levels and subsequent development of NEC in preterm infants.

Link between community-acquired pneumonia and vitamin D levels in older patients

PURPOSE

To investigate the correlation between the level of 25-hydroxyvitamin D [25-(OH)D] and community-acquired pneumonia (CAP) in elderly patients.

METHODS

A total of 163 older patients were chosen from those hospitalized between October 2011 and October 2012. Patients were divided into pneumonia and non-pneumonia groups, and the concentrations of 25-(OH)D (nmol/L) in serum were measured. Clinical data were then compared between the two groups and pneumonia-related risk factors were analyzed using logistic regression.

RESULTS

Among the 163 older hospitalized patients, 49 suffered from pneumonia. Levels of 25-(OH)D, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) were lower (P < 0.05) in the pneumonia group, while severe vitamin D (VitD) deficiency was higher in the pneumonia group (71.4 vs. 19.3%; P < 0.0001). Age and number of hospitalization days were higher in the pneumonia group (P < 0.05). Multivariate logistic regression showed that age and VitD levels were independent risk factors for pneumonia. No significant difference was observed in terms of gender, onset season, body mass index, or smoking and drinking history between the two groups (P > 0.05).

CONCLUSION

The older patients with CAP had a severe VitD deficiency, indicating that low levels of VitD might play an important role in the occurrence and development of CAP.

Oral Tolerance Induced by OVA Intake Ameliorates TNBS-Induced Colitis in Mice

INTRODUCTION

Literature data have shown that the consumption of dietary proteins may cause modulatory effects on the host immune system, process denominated oral tolerance by bystander suppression. It has been shown that the bystander suppression induced by dietary proteins can improve inflammatory diseases such as experimental arthritis. Here, we evaluated the effects of oral tolerance induced by ingestion of ovalbumin (OVA) on TNBS-induced colitis in mice, an experimental model for human Crohn's disease.

METHODS AND RESULTS

Colitis was induced in BALB/c mice by instilling a single dose of TNBS (100 mg/kg) in ethanol into the colon. Tolerized mice received OVA (4mg/mL) dissolved in the drinking water for seven consecutive days, prior to or concomitantly with the intrarectal instillation. Control groups received protein-free water and ethanol by intrarectal route. We observed that either the prior or concomitant induction of oral tolerance were able to reduce the severity of colitis as noted by recovery of body weight gain, improvement of clinical signs and reduction of histological abnormalities. The in vitro proliferation of spleen cells from tolerant colitic mice was lower than that of control mice, the same as the frequencies of CD4+ T cells secreting IL-17 and IFN-γ. The frequencies of regulatory T cells and T cells secreting IL-10 have increased significantly in mice orally treated with OVA. The levels of inflammatory cytokines (IL-17A, TNF-α, IL-6 and IFN-γ) were lower in supernatants of cells from tolerant colitic mice, whereas IL-10 levels were higher.

CONCLUSION

Our data show that the modulation of immune response induced by oral tolerance reduces the severity of experimental colitis. Such modulation may be partially attributed to the increase of Treg cells and reduction of pro-inflammatory cytokines in peripheral lymphoid organs of tolerant mice by bystander suppression.

Northern Latitude but Not Season Is Associated with Increased Rates of Hospitalizations Related to Inflammatory Bowel Disease: Results of a Multi-Year Analysis of a National Cohort

Background and Aims

There is growing evidence that the incidence and severity of inflammatory bowel disease (IBD) may be geographically and seasonally related. Why these associations are observed remains unclear. We assessed the impact of geographic location, season, and exposure to ultraviolet light on disease severity by measuring national hospital IBD-related discharge rates.

Methods

Utilizing the Nationwide Inpatient Sample (NIS), we identified all patients with IBD-related discharges from 2001–2007. Patients were included if they were discharged from states above the 40^th parallel (north) or at or below the 35^th parallel (south); and their discharge fell within the winter (January, February, and March) or summer (July, August, and September). Groups of patients were assessed comparing north to south within each season, and summer to winter within each region. UV index was recorded from the National Weather Service data and compared to monthly discharge rates.

Results

There was a consistent pattern of increased IBD-related hospitalization rates in northern states compared to southern states for both ulcerative colitis and Crohn’s disease. Differences in IBD-related hospitalization rates by season, however, were not uniform across the years studied. UV index was significantly inversely associated although not proportional to discharge rates for both Crohn’s disease and ulcerative colitis.

Conclusions

In the US, there is a significant increased rate of IBD-related hospitalizations in the northern compared to southern states, which not fully explained by differences in UV exposure.

Synergetic and antagonistic effects of combined calcitriol and interferon-β treatment on cytokine production by stimulated PBMCs

BACKGROUND

We evaluated the effects of calcitriol and interferon-β on in vitro PBMC cytokine production from a cohort of 22 healthy adults not on medication.

METHODS

PBMCs were incubated with calcitriol and/or 100 or 400IU interferon-β or nothing, followed by stimulation with concanavalin A.

RESULTS

When combined, calcitriol and interferon-β appeared to potentiate the effects of one another on reducing IL-6. Calcitriol significantly reduced the production of IL-2, IL-4, IL-6, and IFN-γ, while interferon-β significantly reduced production of IL-6 and TNF-α, and increased IL-10.

DISCUSSION

This is the first study to evaluate the effects of combined calcitriol and interferon-β on cytokine production in PBMCs in vitro, demonstrating novel synergetic effects.

Novel CD8+ T-Cell Subsets Demonstrating Plasticity in Patients with Inflammatory Bowel Disease

BACKGROUND

Distinct CD8+ T-cell subsets such as interleukin-17-expressing Tc17 and Foxp3-expressing Tcreg are functionally similar to CD4+ T cells. Though CD4+ T cells are dysregulated in patients with inflammatory bowel disease (IBD), CD8+ T cells are not well investigated. Vitamin D is an environmental factor which influences T-cell subsets. We assessed the prevalence of CD8+ T-cell subsets among peripheral blood mononuclear cells (PBMC) and lamina propria mononuclear cells (LPMC) of patients with Crohn's disease, patients with ulcerative colitis, and healthy controls. We then tested the effect of 1α,25-dihydroxyvitamin D3 on CD8+ T-cell subsets.

METHODS

A total of 73 patients with Crohn's disease, 49 patients with ulcerative colitis, and 47 healthy controls were studied. LPMC or PBMC were isolated and flow cytometry was performed. CD3+ T cells, isolated from PBMC, were cultured with or without 1α,25-dihydroxyvitamin D3, before flow cytometry.

RESULTS

In LPMC, the prevalence of Tcreg was higher in patients with IBD (P < 0.05), whereas Tc17 were higher in patients with ulcerative colitis compared with patients with Crohn's disease and healthy controls (P < 0.05). In PBMC, both Tcreg and Tc17 were higher in patients with IBD (P < 0.01). Double-expressing interferon-γ+ interleukin-17+ and Foxp3+ interleukin-17+ CD8+ T cells were also identified indicating possible CD8+ plasticity. 1α,25-dihydroxyvitamin D3 decreased interferon-γ-expressing Tc1 (P < 0.05), but had no effect on Tc17 or Tcreg.

CONCLUSIONS

The prevalence of novel CD8+ T-cell subsets is altered in patients with IBD. Double-expressing cells indicate plasticity and were identified in patients with IBD. Vitamin D may have a limited effect on CD8+ T cells by decreasing interferon-γ expression.

Serum 25-hydroxyvitamin D concentration is inversely associated with mucosal inflammation in patients with ulcerative colitis

BACKGROUND

Vitamin D exerts anti-inflammatory actions both in vitro and in murine models of colitis. In previous studies, we demonstrated that vitamin D protects against the development of colitis by maintaining the integrity of the intestinal mucosal barrier.

OBJECTIVE

We sought to evaluate whether deficient serum 25 hydroxyvitamin D [25(OH)D] concentrations are associated with increased mucosal inflammation, a loss of epithelial junctional proteins, and an increase in mucosal inflammatory cytokines in patients with ulcerative colitis (UC).

DESIGN

We prospectively enrolled 230 subjects with UC. Serum 25(OH)D concentrations were compared with the Mayo endoscopic score, the total Mayo score, and histologic activity. Colonic mucosal expression concentrations of vitamin D receptor (VDR), E-cadherin, zonula occluden 1 (ZO-1), occludin, claudin-2, tumor necrosis factor α (TNF-α), and interleukin 8 (IL-8) were compared between dichotomous groups with low or high serum 25(OH)D concentrations.

RESULTS

The mean serum 25(OH)D concentration was 21.8 ng/mL. Subjects stratified by concentrations included 12.6% ≥30 ng/mL, 45.6% ≥20 to <30 ng/mL, 37.4% ≥10 to <20 ng/mL, and 4.4% <10 ng/mL. There was an inverse association between serum 25(OH)D concentrations and mucosal inflammation as assessed by the Mayo endoscopy score (P = 0.01), disease activity as indicated by the total Mayo score (P = 0.001), and histologic activity (P = 0.02). A serum 25(OH)D concentration <20 ng/mL was associated with decreased mucosal transcript and protein expression concentrations of VDR, E-cadherin, and occludin as well as decreased protein expression of ZO-1, whereas TNF-α and IL-8 mucosal transcript expression concentrations were increased.

CONCLUSIONS

In UC patients, serum 25(OH)D concentration is inversely correlated with mucosal inflammation and disease activity. These results, coupled with the findings that serum 25(OH)D concentrations correlate with the mucosal expression of VDR as well as epithelial junction proteins and inversely with proinflammatory cytokines, suggest that vitamin D deficiency may contribute to UC inflammation by disrupting epithelial barrier function.

Incidence Trends and Geographical Variability of Pediatric Inflammatory Bowel Disease in Slovenia: A Nationwide Study

Background. The aims of the study were to determine the incidence rate of pediatric inflammatory bowel disease (PIBD) and its trends for the period of 2002–2010 and to assess the geographical distribution of PIBD in Slovenia. Materials and Methods. Medical records of patients (0–18 years) with newly diagnosed IBD during the study period were retrospectively reviewed. Results. The mean incidence rate for IBD in 2002–2010 was 7.6 per 100,000 children and adolescents per year, 4.5 for Crohn's disease (CD), 2.9 for ulcerative colitis (UC), and 0.2 for IBD-unclassified, respectively. The incidence rate increased from 5.8 per 100,000 per year in 2002–2004 to 8.6 in 2005–2007 and remained stable afterwards. Statistically significant difference in the incidence rate between the Northeastern and Southwestern parts of the country was observed (p = 0.025). Conclusion. This nationwide study demonstrates that Slovenia is among the European countries with the highest PIBD incidence. During the study period a substantial rise of PIBD incidence was observed during the first half of the study and it seems to have stabilized in the second half. The significant difference in PIBD incidence between Northeastern and Southwestern parts of the country merits further exploration of the possible environmental factors.

Association Between Inflammatory Bowel Disease and Vitamin D Deficiency: A Systematic Review and Meta-analysis

BACKGROUND

Vitamin D plays a role in several immune-mediated diseases, but its association with inflammatory bowel disease (IBD) is unclear. We conducted a systematic review and meta-analysis to assess the association between IBD and vitamin D deficiency.

METHODS

We searched electronic databases from inception to December 2014 for observational studies reporting the presence of vitamin D deficiency (defined as serum 25-hydroxycholecalciferol [25(OH)D] level of ≤20 ng/mL) in IBD patients and having a control group without IBD. Odds ratios (ORs) were combined using a random-effects model. Meta-regression was performed using latitude as a moderator. Study quality was assessed using the Newcastle-Ottawa scale.

RESULTS

Out of 816 citations, 14 eligible studies were identified, comprising 1891 participants (938 IBD cases and 953 controls). Meta-analysis showed that patients with IBD had 64% higher odds of vitamin D deficiency when compared with controls (OR = 1.64; 95% confidence interval, 1.30-2.08; I = 7%; P < 0.0001). Patients with ulcerative colitis had more than double the odds of vitamin D deficiency when compared with normal controls (OR = 2.28; 95% confidence interval, 1.18-4.41; I = 41%; P = 0.01). Latitude did not influence the association between IBD and vitamin D deficiency (P = 0.34). Generalizability of our results might be limited as we summarized unadjusted ORs, because of nonavailability of adjusted ORs in individual studies.

CONCLUSIONS

IBD is significantly associated with having higher odds of vitamin D deficiency. Well-designed randomized controlled trials and longitudinal studies are needed to further explain the role of vitamin D in IBD pathogenesis and its therapy.

Vitamin D and inflammatory bowel disease

Vitamin D deficiency has been recognized as an environmental risk factor for Crohn's disease since the early 80s. Initially, this finding was correlated with metabolic bone disease. Low serum 25-hydroxyvitamin D levels have been repeatedly reported in inflammatory bowel diseases together with a relationship between vitamin D status and disease activity. Subsequently, low serum vitamin D levels have been reported in various immune-related diseases pointing to an immunoregulatory role. Indeed, vitamin D and its receptor (VDR) are known to interact with different players of the immune homeostasis by controlling cell proliferation, antigen receptor signalling, and intestinal barrier function. Moreover, 1,25-dihydroxyvitamin D is implicated in NOD2-mediated expression of defensin-β2, the latter known to play a crucial role in the pathogenesis of Crohn's disease (IBD1 gene), and several genetic variants of the vitamin D receptor have been identified as Crohn's disease candidate susceptibility genes. From animal models we have learned that deletion of the VDR gene was associated with a more severe disease. There is a growing body of evidence concerning the therapeutic role of vitamin D/synthetic vitamin D receptor agonists in clinical and experimental models of inflammatory bowel disease far beyond the role of calcium homeostasis and bone metabolism.

Vitamin D as an adjunctive therapy in asthma. Part 1: A review of potential mechanisms

Vitamin D deficiency (VDD) is highly prevalent worldwide. The classical role for vitamin D is to regulate calcium absorption form the gastrointestinal tract and influence bone health. Recently vitamin D receptors and vitamin D metabolic enzymes have been discovered in numerous sites systemically supporting diverse extra-skeletal roles of vitamin D, for example in asthmatic disease. Further, VDD and asthma share several common risk factors including high latitude, winter season, industrialization, poor diet, obesity, and dark skin pigmentation. Vitamin D has been demonstrated to possess potent immunomodulatory effects, including effects on T cells and B cells as well as increasing production of antimicrobial peptides (e.g. cathelicidin). This immunomodulation may lead to asthma specific clinical benefits in terms of decreased bacterial/viral infections, altered airway smooth muscle-remodeling and -function as well as modulation of response to standard anti-asthma therapy (e.g. glucocorticoids and immunotherapy). Thus, vitamin D and its deficiency have a number of biological effects that are potentially important in altering the course of disease pathogenesis and severity in asthma. The purpose of this first of a two-part review is to review potential mechanisms whereby altering vitamin D status may influence asthmatic disease.

Vitamin D therapy in inflammatory bowel diseases: who, in what form, and how much?

BACKGROUND

The north–south geographical gradient of inflammatory bowel disease (IBD) prevalence, its epidemiology, the genetic association of vitamin D receptor polymorphisms, and results in animal models suggest that vitamin D plays an important role in the pathogenesis of IBD.

AIMS

The purpose of this review was to critically appraise the effectiveness and safety of vitamin D therapy in patients with IBD.

METHODS

MEDLINE, Scopus and Google Scholar were searched from inception to May 20, 2014 using the terms ‘Crohn’s disease’, ‘ulcerative colitis’ and ‘vitamin D’. Results: Vitamin D deficiency is common in patients with IBD. Limited clinical data suggest an association between low vitamin D concentration and increased disease activity in both ulcerative colitis (UC) and Crohn’s disease (CD). To date, only two small open label trials and one randomized controlled trial have shown a positive effect of vitamin D supplementation on disease activity in patients with CD; no effect has been shown for UC. An optimal vitamin D supplementation protocol for patients with IBD remains undetermined, but targeting serum 25-hydroxy vitamin D [25(OH)D] levels between 30 and 50 ng/mL appears safe and may have benefits for IBD disease activity. Depending on baseline vitamin D serum concentration, ileal involvement in CD, body mass index, and perhaps smoking status, daily vitamin D doses between 1800–10,000 international units/day are probably necessary.

CONCLUSION

Increasing preclinical and clinical evidence suggests a role for vitamin D deficiency in the development and severity of IBD. The possible therapeutic role of vitamin D in patients with IBD merits continued investigation.

The involvement of gut microbiota in inflammatory bowel disease pathogenesis: potential for therapy

Over the past recent years, a great number of studies have been directed toward the evaluation of the human host-gut microbiota interaction, with the goal to progress the understanding of the etiology of several complex diseases. Alterations in the intestinal microbiota associated with inflammatory bowel disease are well supported by literature data and have been widely accepted by the research community. The concomitant implementation of high-throughput sequencing techniques to analyze and characterize the composition of the intestinal microbiota has reinforced the view that inflammatory bowel disease results from altered interactions between gut microbes and the mucosal immune system and has raised the possibility that some form of modulation of the intestinal microbiota may constitute a potential therapeutic basis for the disease. The aim of this review is to describe the changes of gut microbiota in inflammatory bowel disease, focusing the attention on its involvement in the pathogenesis of the disease, and to review and discuss the therapeutic potential to modify the intestinal microbial population with antibiotics, probiotics, prebiotics, synbiotics and fecal microbiota transplantation.

Vitamin D deficiency in Crohn's disease and healthy controls: a prospective case-control study in the Netherlands

BACKGROUND AND AIMS

Vitamin D deficiency has been observed in a wide range of medical conditions including Crohn's disease (CD). We aimed to assess whether CD patients have lower vitamin D levels than healthy controls, and to determine risk factors for vitamin D deficiency.

METHODS

25(OH)D was measured by chemiluminescent immunoassay in serum obtained from 101 CD patients and 41 controls. Demographics, sunlight exposure, dietary vitamin D intake, comorbidities and medication were recorded using validated questionnaires. In CD patients the Harvey-Bradshaw index, Montreal classification and surgical resections were also evaluated. 25(OH)D levels of > 75 nmol/L, between 50 and 75 nmol/L and < 50 nmol/L were considered as normal, suboptimal and deficient, respectively.

RESULTS

Vitamin D levels were rather low but comparable among CD patients and controls (mean 25(OH)D 51.6 nmol/L(± 26.6) in CD, and 60.8 nmol/L(± 27.6) in controls. Multivariate regression analysis revealed BMI, sun protection behaviour, non-Caucasian ethnicity, no use of tanning beds, and no holidays in the last year as significantly associated with serum 25(OH)D levels in CD patients (R=0.62). In the control group no statistically significant factors were identified that had an impact on 25(OH)D serum levels.

CONCLUSIONS

Vitamin D deficiency is common in CD patients, but also in healthy controls. Appropriate vitamin D screening should be advised in patients with CD. Moreover, the positive effect of sunlight on the vitamin D status should be discussed with CD patients, but this should be balanced against the potential risk of developing melanomas, especially in patients using thiopurines.

Vitamin d deficiency is associated with ulcerative colitis disease activity

PURPOSE

Previous studies on experimental mouse models have suggested a role of vitamin D in immune system regulation and IBD disease severity. In this study, we examine the relationship between vitamin D levels and clinical disease activity in human subjects with ulcerative colitis (UC). We hypothesized that patients with vitamin D deficiency will display increased UC disease activity as compared to patients with normal vitamin D levels.

METHODS

A cross-sectional study was performed by querying the outpatient electronic medical record of our health system for patients seen in the gastroenterology clinic from January 2007 to October 2009 who carried both a diagnosis of UC and a documented 25-OH vitamin D level within 30 days of their clinic visit. Demographic and clinical variables were collected. Clinical disease activity was calculated using the six-point partial Mayo index. Active disease was defined as a six-point index score of ≥ 1. Vitamin D deficiency was defined as a 25-OH D level below 30 ng/ml. Data were analyzed using the chi-square distribution test.

RESULTS

Thirty-four patients met inclusion criteria (53 % female, mean age 45.7 ± 24.7 years). Fifteen patients had normal vitamin D levels and 19 patients were vitamin D deficient. Twelve patients had vitamin D levels <20 ng/ml. Vitamin D deficient patients were statistically more likely to have increased disease activity than patients with normal vitamin D levels (p = 0.04), with 68 % of deficient patients displaying active disease compared with 33 % in the sufficient group. There was also a statistically significant association between vitamin D status and need for treatment with steroids, with a higher percentage of vitamin D deficient patients (47 %) requiring such treatment compared with 7 % in the sufficient group (p = 0.02). There was no association between season of visit and disease activity.

CONCLUSION

Vitamin D deficiency is common among patients with active UC, particularly those requiring corticosteroids. Further investigation is needed to determine the clinical utility of vitamin D monitoring in patients with UC and whether there is a role for vitamin D as a treatment for UC.

Increased fracture risk and osteoporosis not associated with vitamin D levels in Malaysian patients with inflammatory bowel disease

INTRODUCTION

Osteoporosis and osteopenia are well-recognized complications of inflammatory bowel disease. Previous studies have suggested that vitamin D deficiency is an important risk factor for the development of osteoporosis. We hypothesized that low vitamin D levels is the main reason for reduced bone mineral density in patients with inflammatory bowel disease. We aimed to study its potential role in Malaysia, which is a tropical country with 3 large ethnic groups. We also sought to examine the relationship between fracture risk and bone mineral density in this group.

METHODOLOGY

Relevant history as well as 25-hydroxycholecalciferol (vitamin D) levels and bone mineral density were obtained. Normal, inadequate, and low vitamin D levels were defined as 61-160 nmol/L (24-64 ng/mL), 30-60 nmol/L (12-24 ng/mL), and less than 30 nmol/L (<12 ng/mL), respectively.

RESULTS

Seventy-two patients were recruited. The prevalence of osteopenia and osteoporosis, respectively, were 58% and 17% in the spine and 51% and 14% in the hip. Mean vitamin D level in the group was low at 45.12 ± 17.4 nmol/L (18.05 ± 6.96 ng/mL), but there was no significant association between bone mineral density and vitamin D level. Twelve patients (16.7%) had a fragility fracture after the diagnosis of inflammatory bowel disease. The cumulative fracture incidence was 10% at 5 years and 35% at 10 years. There was a statistically significant association between osteoporosis of hip and a history of fracture (odds ratio 5.889; 95% confidence interval 1.41-24.53, P = .009).

CONCLUSION

Osteoporosis is prevalent among Malaysian patients with inflammatory bowel disease and is associated with a 6-fold increased risk of fractures. Most inflammatory bowel disease patients had inadequate or low vitamin D levels, but there was no association between vitamin D levels and BMD.

Active vitamin D (1,25-dihydroxyvitamin D3) increases host susceptibility to Citrobacter rodentium by suppressing mucosal Th17 responses

Vitamin D deficiency affects more that 1 billion people worldwide and is associated with an increased risk of developing a number of inflammatory/autoimmune diseases, including inflammatory bowel disease (IBD). At present, the basis for the impact of vitamin D on IBD and mucosal immune responses is unclear; however, IBD is known to reflect exaggerated immune responses to luminal bacteria, and vitamin D has been shown to play a role in regulating bacteria-host interactions. Therefore, to test the effect of active vitamin D on host responses to enteric bacteria, we gave 1,25(OH)(2)D(3) to mice infected with the bacterial pathogen Citrobacter rodentium, an extracellular microbe that causes acute colitis characterized by a strong Th1/Th17 immune response. 1,25(OH)(2)D(3) treatment of infected mice led to increased pathogen burdens and exaggerated tissue pathology. In association with their increased susceptibility, 1,25(OH)(2)D(3)-treated mice showed substantially reduced numbers of Th17 T cells within their infected colons, whereas only modest differences were noted in Th1 and Treg numbers. In accordance with the impaired Th17 responses, 1,25(OH)(2)D(3)-treated mice showed defects in their production of the antimicrobial peptide REG3γ. Taken together, these studies show that 1,25(OH)(2)D(3) suppresses Th17 T-cell responses in vivo and impairs mucosal host defense against an enteric bacterial pathogen.

Improved outcomes with quality improvement interventions in pediatric inflammatory bowel disease

OBJECTIVES

Variations in chronic illness care are common in our health care system and may lead to suboptimal outcomes. Specifically, inconsistent use and suboptimal medication dosing have been demonstrated in the care of patients with inflammatory bowel disease (IBD). Quality improvement (QI) efforts have improved outcomes in conditions such as asthma and diabetes mellitus, but have not been well studied in IBD. We hypothesized that QI efforts would lead to improved outcomes in our pediatric IBD population.

METHODS

A QI team was formed within our IBD center in 2005. By 2007, we began prospectively capturing physician global assessment (PGA) and patient-reported global assessment. Significant QI interventions included creating evidence-based medication guidelines, joining a national QI collaborative, initiation of preclinic planning, and monitoring serum 25-hydroxyvitamin D.

RESULTS

From 2007 to 2010, 505 patients have been followed at our IBD center. During this time, the frequency of patients in clinical remission increased from 59% to 76% (P < 0.05), the frequency of patients who report that their global assessment is >7 increased from 69% to 80% (P < 0.05), and the frequency of patients with a Short Pediatric Crohn's Disease Activity Index (sPCDAI) <15 increased from 60% to 77% (P < 0.05). The frequency of repeat steroid use decreased from 17% to 10% (P < 0.05). We observed an association between the use of a vitamin D supplement (P = 0.02), serum 25-hydroxyvitamin D (P < 0.05), and quiescent disease activity.

CONCLUSIONS

Our results show that significant improvements in patient outcomes are associated with QI efforts that do not rely on new medication or therapies.

Common genetic variation in vitamin D metabolism is associated with liver stiffness

Recently, genome-wide studies identified genetic variants that affect serum 25-hydroxyvitamin D levels in healthy populations (rs12785878, near dehydrocholesterol reductase, DHCR7; rs10741657, at CYP2R1; and rs7041, at vitamin D binding protein, GC). Because vitamin D deficiency is associated with advanced liver disease, we hypothesized that these variants are associated with 25(OH)-vitamin D levels and liver fibrosis. Overall, 712 Caucasian patients with chronic liver diseases were included. Liver fibrosis was assessed by transient elastography (TE) and/or histology. Serum levels of 25(OH)-vitamin D were correlated with TE and fibrosis stages. Genotypes were determined using TaqMan assays and tested for association with vitamin D and liver stiffness. Serum 25(OH)-vitamin D levels were inversely correlated with liver stiffness and histology (P < 0.001). Homozygous carriers of the rare DHCR7 allele or the common CYP2R1 allele presented with reduced 25(OH)-vitamin D levels (P < 0.05). The variant rs12785878 in the DHCR7 locus was associated with liver stiffness in both patients with TE <7.0 kPa and TE between 7.0 and 9.5 kPa. 25(OH)-vitamin D levels correlated with sunshine hours at the time of inclusion (P < 0.001).

CONCLUSION

Common variation in 25(OH)-vitamin D metabolism is associated with liver stiffness in patients presenting with low to moderately increased elasticity. Although the susceptible DHCR7 genotype confers small risk, we speculate that the observed stiffness differences indicate a stronger influence of 25(OH)-vitamin D on initiation rather than progression of hepatic fibrosis.

Management of inflammatory bowel disease with vitamin D: beyond bone health

A relationship between vitamin D and several disorders, including Crohn's disease (CD), has recently been proposed. Vitamin D appears to have several important actions beyond the maintenance of bone health, including various effects on the immune system. Vitamin D deficiency has been implicated in the development of CD, and its analogues may have a role in the treatment of CD. Current research also suggests a role for vitamin D in counteracting some IBD-specific complications, including osteopenia, colorectal neoplasia, and depression. There remains a need for prospective studies to further delineate these relationships. Given current evidence and the apparent safety of vitamin D supplementation, it appears reasonable to screen for and treat vitamin D deficiency in patients with IBD.

Vitamin D in autoimmune, infectious and allergic diseases: a vital player?

Vitamin D is a steroid hormone that is acquired via diet or synthesized in the skin upon UV exposure and needs subsequent hydroxylation steps to become activated as 1,25-dihydroxyvitamin D. While widely known for its role in maintaining bone health, vitamin D receptors have also been identified in different immune cell types. Many immune cells can also convert vitamin D into its bioactive form, thus enhancing the locally available concentrations to those required for the immunomodulatory effects of vitamin D. In this review, we summarize the genetic and epidemiologic data potentially linking vitamin D to autoimmune, infectious and allergic diseases. We also discuss how vitamin D influences the immune responses in each of those conditions based on the data generated using patient samples or preclinical models of each of these diseases.

Vitamin D and inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are the main forms of inflammatory bowel disease (IBD), chronic relapsing-remitting inflammatory conditions of uncertain origin affecting the gastrointestinal tract. Much effort has recently been made both in defining the mechanisms underlying the development of IBD, and in broadening the spectrum of effective treatment. Substantial progress has been made in characterising immune-cell populations and inflammatory mediators in IBD. 1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], the bioactive form of Vitamin D(3), besides having well-known control findings of calcium and phosphorus metabolism, bone formation and mineralization, also has a role in the maintenance of immune- omeostasis. The immune-regulatory role of vitamin D affects both the innate and adaptive immune system contributing to the immune-tolerance of self-structures. Impaired vitamin D supply/regulation, amongst other factors, leads to the development of autoimmune processes in animal models of various autoimmune diseases, including IBD. The administration of vitamin D in these animals leads to improvement of immune-mediated symptoms. Future studies now need to focus on the potential of vitamin D and its derivatives as therapeutic adjuncts in the treatment of IBD.

The possible roles of solar ultraviolet-B radiation and vitamin D in reducing case-fatality rates from the 1918-1919 influenza pandemic in the United States

Deaths during the 1918-1919 influenza pandemic have been linked to both the influenza virus and secondary bacterial lung infections. Case fatality rates and percentage of influenza cases complicated by pneumonia were available from survey data for twelve United States locations in the 1918-1919 pandemic. This study analyzes case fatality rates and cases complicated by pneumonia with respect to estimated summertime and wintertime solar ultraviolet-B (UVB) doses as indicators of population mean vitamin D status. Substantial correlations were found for associations of July UVB dose with case fatality rates (r = -0.72, p = 0.009) and rates of pneumonia as a complication of influenza (r = -0.77, p = 0.005). Similar results were found for wintertime UVB. Vitamin D upregulates production of human cathelicidin, LL-37, which has both antimicrobial and antiendotoxin activities. Vitamin D also reduces the production of proinflammatory cytokines, which could also explain some of the benefit of vitamin D since H1N1 infection gives rise to a cytokine storm. The potential role of vitamin D status in reducing secondary bacterial infections and loss of life in pandemic influence requires further evaluation.

Vitamin D(3) down-regulates proinflammatory cytokine response to Mycobacterium tuberculosis through pattern recognition receptors while inducing protective cathelicidin production

A well-known association between vitamin D(3) and infection with Mycobacterium tuberculosis has previously been reported, but little is known regarding the underlying mechanisms. We have investigated how 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] affects the proinflammatory cytokine production induced by M. tuberculosis. Furthermore, we explored whether 1,25(OH)(2)D(3) influence the production of the protective antimycobacterial peptide cathelicidin. Upon in vitro stimulation with M. tuberculosis, 1,25(OH)(2)D(3) induced a dose-dependent down-regulation of IL-6, TNFα and IFNγ, while increasing the production of IL-10 in culture supernatant as well as cathelicidin mRNA expression. This effect on cytokine response was not due to modulation of T-helper cell differentiation, as T-bet, GATA3, Foxp3 and ROR-γt mRNA expression remained unaffected. Similarly, 1,25(OH)(2)D(3) did not affect suppressor of cytokine signaling (SOCS)1 and SOCS3 mRNA expression. The mechanism whereby 1,25(OH)(2)D(3) inhibited the proinflammatory cytokine response was through reduced expression of the pattern recognition receptors (PRR) - TLR2, TLR4, Dectin-1 and mannose receptor, whose mRNA and protein expression were both reduced. The suppression of PRRs could be restored by a VDR antagonist. Upon M. tuberculosis stimulation, 1,25(OH)(2)D(3) modulates the balance in cytokine production towards an anti-inflammatory profile by repression of TLR2, TLR4, Dectin-1 and mannose receptor expression, while increasing cathelicidin production. These two effects may have beneficial consequences, by reducing the collateral tissue damage induced by proinflammatory cytokines, while the antibacterial effects of cathelicidin are enhanced.

1,25-dihydroxyvitamin D3 modulates cytokine production induced by Candida albicans: impact of seasonal variation of immune responses

BACKGROUND

Our interest in immunological effects produced by vitamin D(3) (1,25(OH)(2)D(3)) and its therapeutic potential prompted us to examine the role of 1,25(OH)(2)D(3) on cytokine production by Candida albicans.

METHODS

Peripheral blood mononuclear cells (PBMC) with stimulated C. albicans and 1,25(OH)(2)D(3), cytokine concentrations were measured in supernatant. Quantitative polymerase chain reaction (qPCR) was performed for T cell transcription factors, SOCS1 and 3. TLR2/4, Dectin-1, and mannose receptor expression was studied using flow cytometry and qPCR. An ex-vivo stimulation study was carried out in healthy volunteers to investigate the seasonality of immune response to C. albicans.

RESULTS

Upon in vitro C. albicans stimulation, 1,25(OH)(2)D(3) induced a dose-dependent, down-regulation of IL-6, TNFα, IL-17, and IFNγ. It also increased IL-10 production. The shift in cytokine profile was not due to 1,25(OH)(2)D(3) augmenting expression of either Thelper differentiation factors or SOCS1 and SOCS3 mRNA. 1,25(OH)(2)D(3) inhibited TLR2, TLR4, Dectin-1, and MR mRNA and protein expression. In our seasonality study, both IL-17 and IFNγ levels were suppressed in summer when 25(OH)D(3) levels were elevated.

CONCLUSION

Vitamin D(3) skews cytokine responses toward an antiinflammatory profile, mediated by suppression of TLR2, TLR4, Dectin-1, and MR transcription, leading to reduced surface expression. The biological relevance of these effects has been confirmed by the seasonality of cytokine responses.

Vitamin D3 treatment of Crohn's disease patients increases stimulated T cell IL-6 production and proliferation

BACKGROUND

Vitamin D3 has shown immune-modulating effects in CD4+ T cells from Crohn's disease patients in vitro.

AIM

To investigate the effects of in vivo vitamin D3 treatment on T cells in Crohn's disease patients.

METHODS

Peripheral blood mononuclear cells (PBMC) were isolated at week 0 and at week 26 from 10 vitamin D3- and 10 placebo-treated Crohn's disease patients participating in a randomized, placebo-controlled, clinical trial study. Monocyte-depleted PBMC were stimulated with anti-CD3 and anti-CD28, and cultured for 7, days, to investigate CD4+ T-cell proliferation and T-cell cytokine production.

RESULTS

In vitamin D3-treated patients, the median 25-hydroxyvitamin D3 levels increased 70 nmol/L compared with -5 nmol/L in the placebo group. Vitamin D3 treatment increased interleukin-6 production (delta = 188 pg/mL, range: -444 to 4071) compared with a decrease in the placebo group (delta = -896 pg/mL, range: -3841 to 1323) (P < 0.02, Wilcoxon rank sum test). Interestingly, vitamin D3 increased the amount of proliferating stimulated CD4+ T cells from median 41% (range: 10-75%) to 56% (range: 26-77%) (P = 0.02, Wilcoxon rank sum test).

CONCLUSIONS

Vitamin D3 treatment of Crohn's disease patients increased the IL-6 levels. Interestingly, vitamin D3 treatment enhanced the CD4+ T cell proliferation.