Mucosal vitamin D signaling in inflammatory bowel disease

Correlation of serum vitamin D levels with serum interleukin-23 levels in patients of ulcerative colitis

Ulcerative Colitis (UC) is a chronic inflammatory condition resulting from an abnormal immune response to gut microbiota, leading to cytokine dysregulation, including elevated interleukin-23 (IL-23) levels. Emerging evidence suggests that vitamin D (VD) plays a crucial role in immune modulation. However, its correlation with IL-23 in UC is not well addressed. This study aims to elucidate the relationship between serum VD and IL-23 levels in UC patients. We included forty-four UC patients and forty-four healthy controls. VD insufficiency was more common in UC patients (n = 14) compared to controls (n = 5). Significant increases in IL-23 levels were observed from remission (46.6 ± 4.3 pg/mL) to severe stages (218.5 ± 62.41 pg/mL), while VD levels did not show a similar trend. IL-23 levels also rose significantly with disease extent, from proctitis to pancolitis. A significant negative correlation was found between VD and IL-23 levels (r = -0.3175; P = 0.035). IL-23 and pulse rate were significant predictors of UC in our cohort. Our findings highlight VD insufficiency to be prevalent in UC patients, with VD levels negatively correlating with IL-23 levels, which increase with disease severity and extent. Further, understanding the interplay between VD and IL-23 will help design therapeutic interventions to modulate immune response and disease progression.

Kuiyangling Enema Alleviates Ulcerative Colitis Mice by Reducing Levels of Intestinal NETs and Promoting HuR/VDR Signaling

Purpose

Kuiyangling is a traditional Chinese medicine formula used for the treatment of ulcerative colitis, but the specific mechanism remains unclear. Imbalance in NETs regulation is one of the important factors contributing to the onset of ulcerative colitis (UC). The HuR/VDR signaling pathway plays a significant role in restoring the intestinal mucosal barrier in UC. The aim of this study is to explore the mechanism of Kuiyangling in the treatment of ulcerative colitis.

Methods

A mouse model of ulcerative colitis using 3% DSS water was considered, and model, normal, Kuiyangling medium- (5 g·kg-1) and high-dose (10 g·kg-1), and mesalazine (50 mg·kg-1) groups were created. Measurements of colon length, spleen index, histopathological variances, subcellular structure observations, ROS content, and NET-related proteins (PAD4, MPO, citH3) were obtained through HE staining, electron microscopy, live imaging, and Western blotting assays. Immunohistochemistry and immunofluorescence analyses were conducted to assess the levels of HuR/VDR protein complex, ZO-1, Occludin, Claudin-7, and intestinal NETs. An ELISA kit was utilized to determine cytokine levels, LC-MS was performed to analyze the composition of Kuiyangling, and next-generation sequencing was conducted for detection of the intestinal mucosal transcriptome.

Results

Kuiyangling reduced DAI, splenic index, and ROS content; maintained mucosal structure; decreased inflammation; and increased colon length and body mass index. Western blotting indicated that Kuiyangling reduced PAD4,MPO, and citH3 levels. Kuiyangling decreased NETs and increased the expression levels of ZO-1, Occludin, and Claudin-7, as well as up-regulating HuR, VDR, and HuR/VDR proteins. Kuiyangling reduced IL-1β, IL-6, and TNF-α levels while increasing TGF-β, IL-10, and IL-37 levels. Kuiyangling reduced inflammatory response proteins and elevated the levels of anti-inflammatory and intestinal barrier proteins, possibly inhibiting the TNF and oxidative phosphorylation signaling pathways.

Conclusion

Kuiyangling enema in treating ulcerative colitis in mice, associated with a reduction in intestinal NETs and enhancement of HuR-mediated intestinal barrier signaling pathways.

The role of vitamin D in treated and refractory ulcerative colitis patients: a case-control study

BACKGROUND

Ulcerative colitis is a form of chronic inflammatory bowel disease (IBD) marked by ongoing inflammation of the mucosal lining that extends from the rectum to the upper part of the colon. Vitamin D regulates immune responses in several autoimmune and inflammatory diseases, including ulcerative colitis. Therefore, the study aims to investigate the role of vitamin D in the pathogenesis and treatment of ulcerative colitis.

METHODS

This case-control study included 94 participants who were divided into four groups. Group 1: people with ulcerative colitis who responded to treatment (n = 24). Group 2: family members of patients who responded to treatment and did not have the disease (n = 24). Group 3: People with ulcerative colitis who are resistant to treatment (n = 23). Group 4: family members of treatment-resistant patients who does not have the disease (n = 23). Groups 1 and 3 were considered as patient groups (n = 47) and groups 2 and 4 as control groups (n = 47). Blood samples were taken and analyzed for complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum vitamin D levels.

RESULTS

The mean age of treatment-responsive patients (group 1) was 45.88 ± 18.51 years, while treatment-resistant patients (group 3) averaged 41.30 ± 13.01 (P = 0.33) years. Serum Vitamin D levels were 24.96 ± 9.66 ng/mL in group 1 and 27.70 ± 12.28 ng/mL in group 3, showing no significant correlation with ulcerative colitis (P = 0.41). All groups had a BMI within the normal range, and mean CRP levels varied significantly across groups. Hemoglobin was significantly lower in group 3 compared to group 1 (P = 0.029), but ESR results showed no significant relationship with ulcerative colitis. Vitamin D levels were highest in patients with lower BMI, and no significant relationships were found between Vitamin D and other risk factors, although extensive colitis was associated with higher Vitamin D levels compared to distal colitis.

CONCLUSION

In this study, there was no significant association between ulcerative colitis and serum levels of vitamin D. However, the small number of patients may limit the conclusions that can be drawn regarding the role of vitamin D in the treatment of ulcerative colitis. Future studies should aim for larger cohorts to provide more definitive insights into this important issue.

Intestinal epithelial vitamin D receptor defense against inflammatory bowel disease via regulating microfold cells

Vitamin D receptor (VDR) is involved in the pathogenesis of inflammatory bowel disease (IBD). However, the mechanism of VDR in IBD is still unclear. Microfold cells (M cells) mediated antigen-sampling pathway is central in developing immune responses to pathogenic and commensal bacteria and related to IBD. We found that Intestinal epithelial cell-specific knockdown of VDR(VDRIEC-KO) increases the susceptibility of mice to experimental colitis induced by sodium dextran sulfate(DSS) by producing more M cells. Knockdown VDR in intestinal epithelial cells increased RANKL-induced microfold cells and promoted the ability of microfold cells to uptake S. Typhimurium (S. T.). Mechanistically, we demonstrated that knockdown VDR promoted the differentiation and maturation of M cells via the Spi-B-dependent pathway. We conclude that M cells may be a potential target of VDR for treating intestinal mucosal barrier dysfunction in IBD.

Influence of Vitamin D Receptor Signalling and Vitamin D on Colonic Epithelial Cell Fate Decisions in Ulcerative Colitis

BACKGROUND AND AIMS

Epidemiological studies have shown that subnormal levels of vitamin D (25[OH]D) are associated with a more aggravated clinical course of ulcerative colitis [UC]. Despite an increased focus on the therapeutic importance of vitamin D and vitamin D receptor [VDR] signalling, the mechanisms underlying the effects of the vitamin D-VDR axis on UC remain elusive. Therefore, we aimed to investigate whether exposure to active vitamin D (1,25[OH]2D3/VDR) signalling in human organoids could influence the maintenance of the colonic epithelium.

METHODS

Intestinal VDR expression was studied by immunohistochemistry, RNA expression arrays, and single-cell RNA sequencing of colonic biopsy specimens obtained from patients with UC and healthy individuals. To characterise the functional and transcriptional effects of 1,25[OH]2D3, we used patient-derived colonic organoids. The dependency of VDR was assessed by knocking out the receptor with CRISPR/Cas9.

RESULTS

Our results suggest that 1,25[OH]2D3/VDR stimulation supports differentiation of the colonic epithelium and that impaired 1,25[OH]2D3/VDR signalling thereby may compromise the structure of the intestinal epithelial barrier, leading to flares of UC. Furthermore, a transcriptional response to VDR activity was observed primarily in fully differentiated cells at the top of the colonic crypt, and this response was reduced during flares of UC.

CONCLUSIONS

We identified an important role of vitamin D signalling in supporting differentiated cell states in the human colonic epithelium, and thereby maintenance of the intestinal barrier integrity. This makes the vitamin D-VDR signalling axis an interesting target for therapeutic efforts to achieve and maintain remission in patients with UC.

The use of vitamin D for patients with inflammatory bowel diseases

As vitamin D (VD) plays an essential role in inflammatory bowel diseases (IBD), this systematic review aimed to update the participation of this vitamin in the prevention or remission of these diseases. This review has included studies in MEDLINE-PubMed, EMBASE, and Cochrane databases. The authors have followed PRISMA (Preferred Reporting Items for a Systematic Review and Meta-analysis) guidelines. According to the inclusion and exclusion criteria, twenty-two randomized clinical trials were selected. In total, 1,209 patients were included in this systematic review: 1034 received only VD and 175 received VD in combination with calcium. The average doses of VD supplementation were from oral 400 IU daily to 10,000 IU per kilogram of body weight. Single injection of 300,000 IU of VD was also used. Several studies have shown the crucial role that VD plays in the therapeutic approach of IBD due to its effects on the immune system. It effectively decreased inflammatory cytokines such as TNF-α and IFN-γ (p<0.05) and provided a reduction in disease activity assessed through different scores such as Crohn's Disease Activity Index (CDAI) (p<0.05) and Ulcerative Colitis Disease Activity Index (UCDAI) (p<0.05). Unfortunately, the available clinical trials are not standardized for of doses and routes of administration. Existing meta-analyses are biased because they compare studies using different doses or treatments in combination with different drugs or supplements such as calcium. Even though VD has crucial effects on inflammatory processes, there is still a need for standardized studies to establish how the supplementation should be performed and the doses to be administered.

MicroRNA-125b mediates Interferon-γ-induced downregulation of the vitamin D receptor in systemic lupus erythematosus

BACKGROUND

The inflammatory factor interferon (IFN)-γ is related to the occurrence and development of systemic lupus erythematosus (SLE). The vitamin D receptor (VDR) has an anti-inflammatory effect and its downregulation is involved in the onset of SLE. Our previous studies have confirmed that the expression of VDR in SLE peripheral blood mononuclear cells (PBMCs) is downregulated, which is negatively correlated with disease activity and inflammation. However, the mechanism underlying VDR downregulation in SLE is unknown.

METHODS

Based on the results of computer simulation analysis, the expression of VDR and four microRNAs (miR-17-3p, miR-34a, miR-346, and miR-125b) in SLE PBMC cells was analyzed under proinflammatory cytokine IFN‑γ treatment, and miR-125b was identified as the target miRNA. The relationship between IFN‑γ, miR-125b, and VDR was further assessed in THP‑1 cells.

RESULTS

We showed that IFN‑γ inhibited the expression of VDR and miR-125b. Further study revealed that VDR mRNA was positively correlated with miR-125b in THP‑1 cells after IFN‑γ intervention. After transfection of miR-125b mimic or inhibitor, the expression of VDR in the miR-125b inhibitor group was lower than in the control group and miR-125b mimic group, while expression in the control group was lower than in miR-125b mimic group. Transfection of miR-125b inhibitor into THP‑1 cells could further promote the ability of IFN‑γ to inhibit VDR.

CONCLUSION

The decrease in VDR expression promotes development of inflammation and SLE. These data suggest that miR-125b may mediate inflammatory factor IFN-γ-induced downregulation of VDR in the pathogenesis of SLE.

Vitamin D modulates disordered lipid metabolism in zebrafish (Danio rerio) liver caused by exposure to polystyrene nanoplastics

In this study, zebrafish (Danio rerio) were exposed to polystyrene nanoplastics (PS-NPs, 80 nm) at 0, 15, or 150 μg/L for 21 days and supplied with a low or high vitamin D (VD) diet (280 or 2800 IU/kg, respectively, indicated by - or +) to determine whether and how VD can regulate lipid metabolism disorder induced by PS-NPs. Six groups were created according to the PS-NP concentration and VD diet status: 0-, 0+, 15-, 15+,150-, and 150 +. Transmission electron microscopy showed that PS-NPs accumulated in the livers of zebrafish, which led to large numbers of vacuoles and lipid droplets in liver cell matrices; this accumulation was most prominent in the 150- group, wherein the number of lipid droplets increased significantly by 136.36%. However, the number of lipid droplets decreased significantly by 76.92% in the 150+ group compared with the 150- group. An examination of additional biochemical indicators showed that the high VD diet partially reversed the increases in the triglyceride and total cholesterol contents induced by PS-NPs (e.g., triglycerides decreased by 58.52% in the 150+ group, and total cholesterol decreased by 44.64% in the 15+ group), and regulated lipid metabolism disorder mainly by inhibiting lipid biosynthesis. Untargeted lipidomics analysis showed that exposure to PS-NPs was associated mainly with changes in the lipid molecular content related to cell membrane function and lipid biosynthesis and that the high VD diet reduced the content of lipid molecules related to lipid biosynthesis, effectively alleviating cell membrane damage and lipid accumulation. These findings highlight the potential of VD to alleviate lipid metabolism disorder caused by PS-NP exposure, thereby providing new insights into how the toxic effects of NPs on aquatic organisms could be reduced.

Vitamin D modulation of brain-gut-virome disorder caused by polystyrene nanoplastics exposure in zebrafish (Danio rerio)

BACKGROUND

Many studies have investigated how nanoplastics (NPs) exposure mediates nerve and intestinal toxicity through a dysregulated brain-gut axis interaction, but there are few studies aimed at alleviating those effects. To determine whether and how vitamin D can impact that toxicity, fish were supplemented with a vitamin D-low diet and vitamin D-high diet.

RESULTS

Transmission electron microscopy (TEM) showed that polystyrene nanoplastics (PS-NPs) accumulated in zebrafish brain and intestine, resulting in brain blood-brain barrier basement membrane damage and the vacuolization of intestinal goblet cells and mitochondria. A high concentration of vitamin D reduced the accumulation of PS-NPs in zebrafish brain tissues by 20% and intestinal tissues by 58.8% and 52.2%, respectively, and alleviated the pathological damage induced by PS-NPs. Adequate vitamin D significantly increased the content of serotonin (5-HT) and reduced the anxiety-like behavior of zebrafish caused by PS-NPs exposure. Virus metagenome showed that PS-NPs exposure affected the composition and abundance of zebrafish intestinal viruses. Differentially expressed viruses in the vitamin D-low and vitamin D-high group affected the secretion of brain neurotransmitters in zebrafish. Virus AF191073 was negatively correlated with neurotransmitter 5-HT, whereas KT319643 was positively correlated with malondialdehyde (MDA) content and the expression of cytochrome 1a1 (cyp1a1) and cytochrome 1b1 (cyp1b1) in the intestine. This suggests that AF191073 and KT319643 may be key viruses that mediate the vitamin D reduction in neurotoxicity and immunotoxicity induced by PS-NPs.

CONCLUSION

Vitamin D can alleviate neurotoxicity and immunotoxicity induced by PS-NPs exposure by directionally altering the gut virome. These findings highlight the potential of vitamin D to alleviate the brain-gut-virome disorder caused by PS-NPs exposure and suggest potential therapeutic strategies to reduce the risk of NPs toxicity in aquaculture, that is, adding adequate vitamin D to diet. Video Abstract.

Mucosal expression of PI3, ANXA1, and VDR discriminates Crohn's disease from ulcerative colitis

Differential diagnosis of inflammatory bowel disease (IBD) to Crohn's disease (CD) or ulcerative colitis (UC) is crucial for treatment decision making. With the aim of generating a clinically applicable molecular-based tool to classify IBD patients, we assessed whole transcriptome analysis on endoscopy samples. A total of 408 patient samples were included covering both internal and external samples cohorts. Whole transcriptome analysis was performed on an internal cohort of FFPE IBD samples (CD, n = 16 and UC, n = 17). The 100 most significantly differentially expressed genes (DEG) were tested in two external cohorts. Ten of the DEG were further processed by functional enrichment analysis from which seven were found to show consistent significant performance in discriminating CD from UC: PI3, ANXA1, VDR, MTCL1, SH3PXD2A-AS1, CLCF1, and CD180. Differential expression of PI3, ANXA1, and VDR was reproduced by RT-qPCR, which was performed on an independent sample cohort of 97 patient samples (CD, n = 44 and UC, n = 53). Gene expression levels of the three-gene profile, resulted in an area under the curve of 0.84 (P = 0.02) in discriminating CD from UC, and therefore appear as an attractive molecular-based diagnostic tool for clinicians to distinguish CD from UC.

Bile acids and their receptors: Potential therapeutic targets in inflammatory bowel disease

Chronic and recurrent inflammatory disorders of the gastrointestinal tract caused by a complex interplay between genetics and intestinal dysbiosis are called inflammatory bowel disease. As a result of the interaction between the liver and the gut microbiota, bile acids are an atypical class of steroids produced in mammals and traditionally known for their function in food absorption. With the development of genomics and metabolomics, more and more data suggest that the pathophysiological mechanisms of inflammatory bowel disease are regulated by bile acids and their receptors. Bile acids operate as signalling molecules by activating a variety of bile acid receptors that impact intestinal flora, epithelial barrier function, and intestinal immunology. Inflammatory bowel disease can be treated in new ways by using these potential molecules. This paper mainly discusses the increasing function of bile acids and their receptors in inflammatory bowel disease and their prospective therapeutic applications. In addition, we explore bile acid metabolism and the interaction of bile acids and the gut microbiota.

Manipulating Microbiota in Inflammatory Bowel Disease Treatment: Clinical and Natural Product Interventions Explored

Inflammatory bowel disease (IBD) is a complex multifactorial chronic inflammatory disease, that includes Crohn's disease (CD) and ulcerative colitis (UC), having progressively increasing global incidence. Disturbed intestinal flora has been highlighted as an important feature of IBD and offers promising strategies for IBD remedies. A brief overview of the variations occurring in intestinal flora during IBD is presented, and the role of the gut microbiota in intestinal barrier maintenance, immune and metabolic regulation, and the absorption and supply of nutrients is reviewed. More importantly, we review drug research on gut microbiota in the past ten years, including research on clinical and natural drugs, as well as adjuvant therapies, such as Fecal Microbiota Transplantation and probiotic supplements. We also summarize the interventions and mechanisms of these drugs on gut microbiota.

Vitamin D improves irritable bowel syndrome symptoms: A meta-analysis

Background & aims

Approximately 5%-10% of the population in most geographical regions suffer from irritable bowel syndrome (IBS), which creates a significant burden on individual patients, their families, and society. Recent advances in IBS therapies have indicated that vitamin D supplementation is potential to relieve its symptoms, but evidence of this is lacking. This meta-analysis aimed to estimate the effect of vitamin D on gastrointestinal (GI) symptoms in IBS patients.

Methods

The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched from their inception to March 2022. Statistical analyses were performed with Stata 12.0 and Review Manager 5.4, and statistical significance was defined as P < 0.05. The pooled results are presented as weighted mean differences (WMD) and 95% confidence intervals (CI).

Results

The meta-analysis including 6 randomized controlled trials (RCT) with 572 patients found a significant difference in IBS symptom severity score (WMD, -34.88; 95% CI, -62.48 to -7.27; P = 0.013; random-effects model) but no significant difference in IBS quality of life score (WMD, 3.33; 95% CI, -5.12 to -11.77; P = 0.440; random-effects model).

Conclusions

Overall, IBS patients may benefit from vitamin D supplementation to reduce the GI symptoms.

Vitamin D and malabsorptive gastrointestinal conditions: A bidirectional relationship?

This paper is one of the outcomes of the 5th International Conference "Controversies in Vitamin D" held in Stresa, Italy from 15 to 18 September 2021 as part of a series of annual meetings which was started in 2017. The scope of these meetings is to discuss controversial issues about vitamin D. Publication of the outcomes of the meeting in international journals allows a wide sharing of the most recent data with the medical and academic community. Vitamin D and malabsorptive gastrointestinal conditions was one of the topics discussed at the meeting and focus of this paper. Participants to the meeting were invited to review available literature on selected issues related to vitamin D and gastrointestinal system and to present their topic to all participants with the aim to initiate a discussion on the main outcomes of which are reported in this document. The presentations were focused on the possible bidirectional relationship between vitamin D and gastrointestinal malabsorptive conditions such as celiac disease, inflammatory bowel diseases (IBDs) and bariatric surgery. In fact, on one hand the impact of these conditions on vitamin D status was examined and on the other hand the possible role of hypovitaminosis D on pathophysiology and clinical course of these conditions was also evaluated. All examined malabsorptive conditions severely impair vitamin D status. Since vitamin D has known positive effects on bone this in turn may contribute to negative skeletal outcomes including reduced bone mineral density, and increased risk of fracture which may be mitigated by vitamin D supplementation. Due to the immune and metabolic extra-skeletal effects there is the possibility that low levels of vitamin D may negatively impact on the underlying gastrointestinal conditions worsening its clinical course or counteracting the effect of treatment. Therefore, vitamin D status assessment and supplementation should be routinely considered in all patients affected by these conditions. This concept is strengthened by the existence of a possible bidirectional relationship through which poor vitamin D status may negatively impact on clinical course of underlying disease. Sufficient elements are available to estimate the desired threshold vitamin D level above which a favourable impact on the skeleton in these conditions may be obtained. On the other hand, ad hoc controlled clinical trials are needed to better define this threshold for obtaining a positive effect of vitamin D supplementation on occurrence and clinical course of malabsorptive gastrointestinal diseases.

Immunomodulatory Properties of Vitamin D in the Intestinal and Respiratory Systems

Vitamin D plays a crucial role in modulating the innate immune response by interacting with its intracellular receptor, VDR. In this review, we address vitamin D/VDR signaling and how it contributes to the regulation of intestinal and respiratory microbiota. We additionally review some components of the innate immune system, such as the barrier function of the pulmonary and intestinal epithelial membranes and secretion of mucus, with their respective modulation by vitamin D. We also explore the mechanisms by which this vitamin D/VDR signaling mounts an antimicrobial response through the transduction of microbial signals and the production of antimicrobial peptides that constitute one of the body’s first lines of defense against pathogens. Additionally, we highlight the role of vitamin D in clinical diseases, namely inflammatory bowel disease and acute respiratory distress syndrome, where excessive inflammatory responses and dysbiosis are hallmarks. Increasing evidence suggests that vitamin D supplementation may have potentially beneficial effects on those diseases.

Effects of Medium- and Long-Chain Structured Triacylglycerol on the Therapeutic Efficacy of Vitamin D on Ulcerative Colitis: A Consideration for Efficient Lipid Delivery Systems

Due to intestinal malabsorption and poor water solubility, vitamin D (VitD) deficiency in ulcerative colitis (UC) continues to increase. Medium- and long-chain triacylglycerols (MLCT), as novel lipids, have been widely applied in the field of functional food and medicine nutrition. Our previous studies showed that the difference in MLCT structure could affect VitD bioaccessibility in vitro. In this study, our results further indicate that, although identical in fatty acid composition, structured triacylglycerol (STG) had a higher VitD bioavailability (AUC = 15470.81 μg/L × h) and metabolism efficacy [s-25(OH)D, p < 0.05] than physical mixtures of triacylglycerol (PM), which further affect the amelioration efficiency in UC mice. Compared with PM, the damage of colonic tissues, intestinal barrier proteins, and inflammatory cytokines in STG showed better amelioration at the same dose of VitD. This study provides a comprehensive understanding of the mechanism of nutrients in different carriers and a solution for developing nutrients with high absorption efficiency.

Vitamin D and Microbiome: Molecular Interaction in Inflammatory Bowel Disease Pathogenesis

Studies of systemic autoimmune diseases point to characteristic microbial patterns in various diseases, including inflammatory bowel disease (IBD). Autoimmune diseases, and IBD in particular, show a predisposition to vitamin D deficiency, leading to alterations in the microbiome and disruption of intestinal epithelial barrier integrity. In this review, we examine the role of the gut microbiome in IBD and discuss how vitamin D-vitamin D receptor (VDR)-associated molecular signaling pathways contribute to the development and progression of IBD through their effects on gut barrier function, the microbial community, and immune system function. The present data demonstrate that vitamin D promotes the proper function of the innate immune system by acting as an immunomodulator, exerting anti-inflammatory effects, and critically contributing to the maintenance of gut barrier integrity and modulation of the gut microbiota, mechanisms that may influence the IBD development and progression. VDR regulates the biological effects of vitamin D and is related to environmental, genetic, immunologic, and microbial aspects of IBD. Vitamin D influences the distribution of the fecal microbiota, with high vitamin D levels associated with increased levels of beneficial bacterial species and lower levels of pathogenic bacteria. Understanding the cellular functions of vitamin D-VDR signaling in intestinal epithelial cells may pave the way for the development of new treatment strategies for the therapeutic armamentarium of IBD in the near future.

Associations between Vitamin D Deficiency and Carbohydrate Intake and Dietary Factors in Taiwanese Pregnant Women

This cross-sectional observation study investigated the vitamin D (VD) status in Taiwanese pregnant women and the effects of VD supplementation and macronutrient intake on serum 25-hydroxy-vitamin D (25[OH]D) level. Data on VD intake, daily sunlight exposure, and carbohydrate intake were obtained from 125 pregnant women at 30−37 weeks’ gestation. Serum 25[OH]D level was measured before delivery in all enrolled women; and the mean 25(OH)D level was 43 nmol/L or 17.2 ng/mL. The 25(OH)D level was significantly correlated with total VD intake of pregnant women (r = 0.239; p = 0.007). The severe VD deficiency group (n = 16; mean of 25(OH)D level = 8.5 ng/mL) had significantly lower total VD intake and supplementation than the groups with VD deficiency (n = 69), insufficiency (n = 32), and sufficiency (n = 8). Those with ≥400 IU/day total VD intake (including VD from food and supplementation) had significantly higher 25(OH)D concentration than those with <400 IU/day total VD intake. Those with 400 IU/day VD supplementation could significantly increase serum 25(OH)D concentrations for pregnant women. Among 85 pregnant women with carbohydrate intake of ≥300 g/day, serum 25(OH)D levels were negatively correlated with carbohydrate intake (p = 0.031). In conclusion, VD deficiency was highly prevalent in Taiwanese pregnant women. VD supplementation was the most effective method for increasing 25(OH)D concentration in pregnant women. Higher carbohydrate intake might reduce 25(OH)D levels.

HuanglianGanjiang Tang alleviates DSS-induced colitis in mice by inhibiting necroptosis through vitamin D receptor

ETHNOPHARMACOLOGICAL RELEVANCE

HuanglianGanjiang Tang (HGT) is a classic prescription of traditional Chinese medicine (TCM) recorded in Dan Xi Xin Fa, which was used to alleviate manifestations like diarrhea, abdominal pain and hemafecia. In current clinical practices, HGT is adopted for the treatment of ulcerative colitis (UC) and affords good curative effect. However, the underlying mechanism deserves further elucidation.

AIM OF THE STUDY

UC is a hard-to-curable and easy-to-recurrent inflammatory disease. This study is to evaluate the potential therapeutics and explore the molecular mechanism of HGT on UC in the mouse model.

MATERIALS AND METHODS

The components of HGT extracts were identified by HPLC. The colitis of mice was induced by 3% (w./v.) dextran sulfate sodium (DSS). The HGT decoction was prepared through boiling and centrifuging. The mice were given HGT decoction via oral gavage (0.34 g/ml & 0.68 g/ml; 5 ml/kg b.w.). The protective role of HGT on colitis mice was evaluated by body weight change, colon length, disease activity index (DAI) and histological scores. The expressions of necroptosis-related and vitamin D receptor (VDR)-related proteins were measured by Western blot, RT-qPCR and immunofluorescence.

RESULTS

HGT could significantly reduce the loss of body weight and colon length in colitis mice, and alleviated the DAI and histological scores. Mechanically, HGT also promoted the expression of E-cadherin, Occludin, ZO-1 and VDR, and reduced the level of intestinal inflammatory cytokines, such as, IL-6, IL-1β and TNF-α. Besides, HGT downregulated the protein level of p-RIPK3, p-RIPK1 and p-MLKL while upregulated the protein level of Caspase-8 in colon tissue compared to the model group.

CONCLUSION

Our study addressed that HGT can alleviate DSS-induced colitis of mice through inhibiting colonic necroptosis by upregulating the level of VDR.

Pleiotropic Effects of Vitamin D in Patients with Inflammatory Bowel Diseases

The multifaceted activity of vitamin D in patients with inflammatory bowel disease (IBD) presents a challenge for further research in this area. Vitamin D is involved in the regulation of bone mineral metabolism, it participates in the regulation of the immune system, and it is an underlying factor in the pathogenesis of IBD. Additionally, vitamin D affects Th1 and Th2 lymphocytes, influencing the release of cytokines and inhibiting tumor necrosis factor (TNF) expression and the wnt/β-catenin pathway. As far as IBDs are concerned, they are associated with microbiota dysbiosis, abnormal inflammatory response, and micronutrient deficiency, including vitamin D hypovitaminosis. In turn, the biological activity of active vitamin D is regulated by the vitamin D receptor (VDR) which is associated with several processes related to IBD. Therefore, in terms of research on vitamin D supplementation in IBD patients, it is essential to understand the metabolic pathways and genetic determinants of vitamin D, as well as to identify the environmental factors they are subject to, not only in view of osteoporosis prevention and therapy, but primarily concerning modulating the course and supplementation of IBD pharmacotherapy.

Nutraceuticals for the Treatment of IBD: Current Progress and Future Directions

Inflammatory bowel disease (IBD) is a chronic relapsing-remitting inflammatory disease of the gastrointestinal tract. Patients are usually diagnosed in adolescence and early adulthood and need lifelong treatment. In recent years, it has been found that diet plays an important role in the pathogenesis of IBD. Diet can change intestinal barrier function, affect the structure and function of intestinal flora, and promote immune disorder, thus promoting inflammation. Many patients believe that diet plays a role in the onset and treatment of the disease and changes their diet spontaneously. This review provides some insights into how nutraceuticals regulate intestinal immune homeostasis and improve intestinal barrier function. We reviewed the research results of dietary fiber, polyphenols, bioactive peptides, and other nutraceuticals in the prevention and treatment of IBD and sought better alternative or supplementary treatment methods for IBD patients.

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.

A systems genomics approach to uncover patient-specific pathogenic pathways and proteins in ulcerative colitis

We describe a precision medicine workflow, the integrated single nucleotide polymorphism network platform (iSNP), designed to determine the mechanisms by which SNPs affect cellular regulatory networks, and how SNP co-occurrences contribute to disease pathogenesis in ulcerative colitis (UC). Using SNP profiles of 378 UC patients we map the regulatory effects of the SNPs to a human signalling network containing protein-protein, miRNA-mRNA and transcription factor binding interactions. With unsupervised clustering algorithms we group these patient-specific networks into four distinct clusters driven by PRKCB, HLA, SNAI1/CEBPB/PTPN1 and VEGFA/XPO5/POLH hubs. The pathway analysis identifies calcium homeostasis, wound healing and cell motility as key processes in UC pathogenesis. Using transcriptomic data from an independent patient cohort, with three complementary validation approaches focusing on the SNP-affected genes, the patient specific modules and affected functions, we confirm the regulatory impact of non-coding SNPs. iSNP identified regulatory effects for disease-associated non-coding SNPs, and by predicting the patient-specific pathogenic processes, we propose a systems-level way to stratify patients.

Therapeutic effect of indirubin-loaded bovine serum albumin nanoparticules on ulcerative colitis

Indirubin is considered to have promising potential in the treatment of ulcerative colitis (UC). However, poor aqueous solubility and low bioavailability limit its clinical application. We produced indirubin-loaded bovine serum albumin nanoparticles (INPs) and characterized their drug encapsulation efficiency, drug-loading capacity, capacity to release indirubin in vitro and short-term physical stability. We also investigated the pharmacokinetics of INPs in mice. We then compared the curative effects of INPs and indirubin against dextran sulfate sodium-induced colitis in mice and 3D cultured biopsies from patients with UC. In the mouse model, the outcomes of INP treatment, including the disease activity index and serous levels of interleukin (IL)-1β and IL-10, were significantly different from those of indirubin treatment. Similarly, when we administered INPs and indirubin to the ex vivo colonic tissues of patients with UC, the effect of INPs was stronger than that of indirubin for most antioxidant and anti-inflammatory biomarkers. The results of both the animal trial and ex vivo experiment indicate that the therapeutic effect of indirubin was further enhanced by the carrier system, making it a highly promising medical candidate for UC.

Micronutrient Improvement of Epithelial Barrier Function in Various Disease States: A Case for Adjuvant Therapy

The published literature makes a very strong case that a wide range of disease morbidity associates with and may in part be due to epithelial barrier leak. An equally large body of published literature substantiates that a diverse group of micronutrients can reduce barrier leak across a wide array of epithelial tissue types, stemming from both cell culture as well as animal and human tissue models. Conversely, micronutrient deficiencies can exacerbate both barrier leak and morbidity. Focusing on zinc, Vitamin A and Vitamin D, this review shows that at concentrations above RDA levels but well below toxicity limits, these micronutrients can induce cell- and tissue-specific molecular-level changes in tight junctional complexes (and by other mechanisms) that reduce barrier leak. An opportunity now exists in critical care—but also medical prophylactic and therapeutic care in general—to consider implementation of select micronutrients at elevated dosages as adjuvant therapeutics in a variety of disease management. This consideration is particularly pointed amidst the COVID-19 pandemic.

Molecular manipulations and intestinal stem cell-derived organoids in inflammatory bowel disease

The pathogenesis of inflammatory bowel diseases (IBD) involves genetic predisposition, environmental factors, and a broadly dysregulated intestinal immune response to the commensal intestinal microflora. The interface between genetic predisposition and environmental factors is reflected in the epigenetic regulation at the transcriptional level. Treatment targets now involve mucosal and histological healing, but the future might additionally include normalization of intestinal cellular functions also at the molecular level, for example comprising complete restoration of phenotypic, genotypic, and epigenetic states. Recent developments in patient-derived epithelial intestinal stem cell (ISC) organoid technologies have opened exciting new therapeutic opportunities to potentially attain molecular healing by combining stem cell therapy with molecular manipulations using (epi)drugs and/or CRISPR/Cas9 genome editing. Here, we are the first to discuss the possibility for phenotypic, genotypic, and epigenetic restoration via molecular manipulations and stem cell therapy in IBD from a clinical perspective.

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.

Bacterial and Viral Co-Infection in the Intestine: Competition Scenario and Their Effect on Host Immunity

Bacteria and viruses are both important pathogens causing intestinal infections, and studies on their pathogenic mechanisms tend to focus on one pathogen alone. However, bacterial and viral co-infections occur frequently in clinical settings, and infection by one pathogen can affect the severity of infection by another pathogen, either directly or indirectly. The presence of synergistic or antagonistic effects of two pathogens in co-infection can affect disease progression to varying degrees. The triad of bacterial–viral–gut interactions involves multiple aspects of inflammatory and immune signaling, neuroimmunity, nutritional immunity, and the gut microbiome. In this review, we discussed the different scenarios triggered by different orders of bacterial and viral infections in the gut and summarized the possible mechanisms of synergy or antagonism involved in their co-infection. We also explored the regulatory mechanisms of bacterial–viral co-infection at the host intestinal immune interface from multiple perspectives.

Emodin Protects Sepsis Associated Damage to the Intestinal Mucosal Barrier Through the VDR/ Nrf2 /HO-1 Pathway

Aims: Emodin is an anthraquinone extracted from Polygonum multiflorum, which has potential anti-inflammatory and anti-oxidative stress effects. However, the possible protective mechanism of emodin is unclear. The purpose of this study was to investigate the protective mechanism of emodin against cecal ligation and puncture and LPS-induced intestinal mucosal barrier injury through the VDR/ Nrf2 /HO-1 signaling pathway.

Methods: We established a mouse model of sepsis by cecal ligation and puncture (CLP), and stimulated normal intestinal epithelial cells with lipopolysaccharide (LPS). VDR in cellswas down-regulated by small interfering ribonucleic acid (siRNA) technology.Mice were perfused with VDR antagonists ZK168281 to reduce VDR expression and mRNA and protein levels of VDR and downstream molecules were detected in cells and tissue. Inflammation markers (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6)) and oxidative stress markers (superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH)) were measured in serum and intestinal tissueby enzym-linked immunosorbent assay. The expression of VDR in intestinal tissue was detected by immunofluorescence. Histopathological changes were assessed by hematoxylin and eosin staining.

Results: In NCM460 cells and animal models, emodin increased mRNA and protein expression of VDR and its downstream molecules. In addition, emodin could inhibit the expressions of TNF-α, IL-6 and MDA in serum and tissue, and increase the levels of SOD and GSH. The protective effect of emodin was confirmed in NCM460 cells and mice, where VDR was suppressed. In addition, emodin could alleviate the histopathological damage of intestinal mucosal barrier caused by cecal ligation and puncture.

Conclusion: Emodin has a good protective effect against sepsis related intestinal mucosal barrier injury, possibly through the VDR/ Nrf2 /HO-1 pathway.

Probiotics and Vitamin D/Vitamin D Receptor Pathway Interaction: Potential Therapeutic Implications in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD) are chronic conditions of unknown etiology and immunomediated pathogenesis. In the last years, the comprehension of the complex mechanisms involved in the intestinal mucosal homeostasis, and the analysis of the alterations potentially leading to inflammatory pathologic states, has consistently increased. Specifically, the extraordinary impulse in the field of research of the intestinal microbiome has opened the door to the investigation of possible novel approaches to the diagnosis, management and therapeutic applications in IBD. In line with that, administration of probiotic bacteria has been intensely evaluated, leading to much more exciting results in experimental models than in clinical practice. Considering the consistent heterogeneity of the available studies on probiotics, the increased knowledge of the properties of the single bacterial species would ideally lead to unravel potential mechanisms of action that may bring therapeutic applications in specific pathologic condition. Among the relevant molecular pathways for mucosal homeostasis maintenance, the vitamin D/vitamin D receptor (VDR) pathway has been intensely studied in the very last years. In fact, besides osteometabolic functions, the vitamin D exerts important homeostatic effects in the organism at multiple levels, such as immunomodulation, inflammation control, and microbiota regulation, which are likely to play a relevant role in intestinal mucosa protection. In the present review, recent findings about probiotic applications in IBD and mechanisms of action linking vitamin D/VDR pathway to IBD are reported. Available evidence for probiotic effect on vitamin D/VDR are reviewed and potential future application in IBD patients are discussed. At present, many aspects of IBD pathogenesis are still obscure, and current therapeutic options for IBD treatment are at best suboptimal. The increasing comprehension of the different pathways involved in IBD pathogenesis will lead to novel findings ideally leading to potential clinical applications. Microbiota manipulation and vitamin/VDR pathway appear a promising field for future research and therapeutic developments.

The Cooperation of Bifidobacterium longum and Active Vitamin D3 on Innate Immunity in Salmonella Colitis Mice via Vitamin D Receptor

Salmonella spp. remains a major public health problem for the whole world. Intestinal epithelial cells serve as an essential component of the mucosal innate immune system to defend against Salmonella infection. Our in vitro studies showed probiotics and active vitamin D have similar effects on innate immunity in Salmonella-infected intestinal epithelial cells, including antimicrobial peptide and inflammatory responses, to protect the host against infection while downregulating detrimental overwhelming inflammation. Hence, we investigated the synergistic effects of probiotics and active vitamin D on Salmonella colitis and translocation to liver and spleen by in vitro and in vivo studies. The Salmonella colitis model is conducted with 6-8 w/o male C57BL/6 mice: Streptomycin (20 mg/mouse p.o.)-pretreated C57BL/6 mice are mock infected with sterile PBS or infected orally with 1 × 108 CFU of a S. Typhimurium wild-type strain SL1344 for 48 h. The mice in the treated groups received 1, 25D daily (0.2 ug/25 g/d) and/or 1 × 108 CFU of probiotics, Lactobacillus rhamnosus GG (LGG) and Bifidobacterium longum (BL) by intragastric administration for 14 days. The in vivo study demonstrated the combination of probiotic Bifidobacterium longum and active vitamin D3 had the synergistic effects on reducing the severity of Salmonella colitis and body weight loss in C57BL/6 mice by reducing cecal inflammatory mIL-6, mIL-8, mTNF-α and mIL-1β mRNA responses, blocking the translocation of bacteria while enhancing the antimicrobial peptide mhBD-3 mRNA in comparison to the infection only group. However, LGG did not have the same synergistic effects. It suggests the synergistic effects of Bifidobacterium longum and active vitamin D on the antibacterial and anti-inflammatory responses in Salmonella colitis. Therefore, our in vivo studies demonstrated that the combination of probiotic Bifidobacterium longum and active vitamin D3 has the synergistic effects on reducing the severity of Salmonella colitis via the suppression of inflammatory responses, and blocking the translocation of bacteria through the enhancement of antimicrobial peptides.

Vitamin D metabolism and disorders in dogs and cats

Vitamin D plays an important role in regulating calcium metabolism and in the development and maintenance of skeletal health of companion animals. There is also a growing interest in understanding the role vitamin D plays in non-skeletal health in both human and veterinary patients. This review provides an update of our current understanding of vitamin D biology in dogs and cats and gives an overview of how vitamin D metabolism can be assessed in companion animals. Congenital and acquired vitamin D disorders are then summarised before the review concludes with a summary of recent studies which have explored the role of vitamin D in the development and outcomes of non-skeletal diseases of dogs and cats.

Hygiene hypothesis and autoimmune diseases: A narrative review of clinical evidences and mechanisms

Since the start of the "modern era", characterized by the increase in urbanization, a progressive attention to hygiene and autoimmune conditions has considerably grown. Although these diseases are often multifactorial, it was demonstrated that environment factors such as pollution, diet and lifestyles may play a crucial role together with genetic signature. Our research, based on the newest and most significant literature of this topic, highlights that the progressive depletion of microbes and parasites due to increased socioeconomic improvement, may lead to a derangement of immunoregulatory mechanisms. Moreover, special attention was given to the complex interplay between microbial agents, as gut microbiome, diet and vitamin D supplementation with the aim of identifying promising future therapeutic options. In conclusion, autoimmunity cannot be limited to hygiene-hypothesis, but from the point of view of precision medicine, this theory represents a fundamental element together with the study of genomics, the microbiome and proteomics, in order to understand the complex functioning of the immune system.

Vitamin D Signaling in Gastro-Rheumatology: From Immuno-Modulation to Potential Clinical Applications

In the last decades, the comprehension of the pathophysiology of bone metabolism and its interconnections with multiple homeostatic processes has been consistently expanded. The branch of osteoimmunology specifically investigating the link between bone and immune system has been developed. Among molecular mediators potentially relevant in this field, vitamin D has been recently pointed out, and abnormalities of the vitamin D axis have been described in both in vitro and in vivo models of inflammatory bowel diseases (IBD) and arthritis. Furthermore, vitamin D deficiency has been reported in patients affected by IBD and chronic inflammatory arthritis, thus suggesting the intriguing possibility of impacting the disease activity by the administration vitamin D supplements. In the present review, the complex interwoven link between vitamin D signaling, gut barrier integrity, microbiota composition, and the immune system was examined. Potential clinical application exploiting vitamin D pathway in the context of IBD and arthritis is presented and critically discussed. A more detailed comprehension of the vitamin D effects and interactions at molecular level would allow one to achieve a novel therapeutic approach in gastro-rheumatologic inflammatory diseases through the design of specific trials and the optimization of treatment protocols.