Vitamin D and mucosal immune function

Interplay of calcium, vitamin D, and parathormone in the milieu of infections and immunity: Reassessed in the context of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is recognized for inducing severe respiratory symptoms like cough, and shortness of breathing. Although symptom severity varies, some individuals remain asymptomatic. This virus has sparked a global pandemic, imposing a substantial rate of mortality or morbidity, with extended periods of illness reported. People with underlying medical issues and the elderly are more likely to experience adverse results. The virus's frequent mutations pose challenges for medical professionals, necessitating adaptable therapeutic and preventive strategies. Vitamin D, a versatile regulatory molecule, not only influences physiological processes such as serum calcium regulation but also exhibits immunomodulatory functions. Calcium ions play a crucial role as secondary signal transduction molecules, impacting diverse cellular functions and maintaining homeostasis through ion channel regulation. Parathormone, another key regulator of serum calcium, often acts antagonistically to vitamin D. This review delves into the interplay of vitamin D, calcium, and parathormone, exploring their possible influence on the progression of COVID-19. The intricate signaling involving these elements contributes to adverse prognosis, emphasizing the need for comprehensive understanding. Monitoring and controlling these physiological factors and associated pathways have shown the potential to alter disease outcomes, underscoring the importance of a holistic approach.

Topical Vitamin D Prevents Bone Loss and Inflammation in a Mouse Model

There is a strong association between vitamin D levels and periodontal disease based on numerous epidemiological studies. We have previously shown that experimental deficiency of serum vitamin D in mice leads to gingival inflammation and alveolar bone loss. Treatment of cultured oral epithelial cells with the active form of vitamin D, 1,25(OH)2 vitamin D3 (1,25(OH)2D3), inhibits the extracellular growth and intracellular invasion of bacteria associated with periodontal disease. Maintenance of periodontal health may be due in part to the anti-inflammatory activities of vitamin D. Furthermore, this hormone can induce the expression of an antimicrobial peptide in cultured oral epithelial cells. We have shown that oral epithelial cells are capable of converting inactive vitamin D to the active form, suggesting that topical treatment of the oral epithelium with inactive vitamin D could prevent the development of periodontitis. We subjected mice to ligature-induced periodontitis (LIP), followed by daily treatment with inactive vitamin D or 1,25(OH)2D3. Treatment with both forms led to a reduction in ligature-induced bone loss and inflammation. Gingival tissues obtained from vitamin D-treated LIP showed production of specialized proresolving mediators (SPM) of inflammation. To examine the mechanism, we demonstrated that apical treatment of 3-dimensional cultures of primary gingival epithelial cells with vitamin D prevented lipopolysaccharide-induced secretion of proinflammatory cytokines and led to a similar production of SPM. Analysis of the oral microbiome of the mice treated with vitamin D showed significant changes in resident bacteria, which reflects a shift toward health-associated species. Together, our results show that topical treatment of oral tissues with inactive vitamin D can lead to the maintenance of periodontal health through the regulation of a healthy microbiome and the stimulation of resolution of inflammation. This strongly supports the development of a safe and effective vitamin D-based topical treatment or preventive agent for periodontal inflammation and disease.

Interactions between Dietary Antioxidants, Dietary Fiber and the Gut Microbiome: Their Putative Role in Inflammation and Cancer

The intricate relationship between the gastrointestinal (GI) microbiome and the progression of chronic non-communicable diseases underscores the significance of developing strategies to modulate the GI microbiota for promoting human health. The administration of probiotics and prebiotics represents a good strategy that enhances the population of beneficial bacteria in the intestinal lumen post-consumption, which has a positive impact on human health. In addition, dietary fibers serve as a significant energy source for bacteria inhabiting the cecum and colon. Research articles and reviews sourced from various global databases were systematically analyzed using specific phrases and keywords to investigate these relationships. There is a clear association between dietary fiber intake and improved colon function, gut motility, and reduced colorectal cancer (CRC) risk. Moreover, the state of health is reflected in the reciprocal and bidirectional relationships among food, dietary antioxidants, inflammation, and body composition. They are known for their antioxidant properties and their ability to inhibit angiogenesis, metastasis, and cell proliferation. Additionally, they promote cell survival, modulate immune and inflammatory responses, and inactivate pro-carcinogens. These actions collectively contribute to their role in cancer prevention. In different investigations, antioxidant supplements containing vitamins have been shown to lower the risk of specific cancer types. In contrast, some evidence suggests that taking antioxidant supplements can increase the risk of developing cancer. Ultimately, collaborative efforts among immunologists, clinicians, nutritionists, and dietitians are imperative for designing well-structured nutritional trials to corroborate the clinical efficacy of dietary therapy in managing inflammation and preventing carcinogenesis. This review seeks to explore the interrelationships among dietary antioxidants, dietary fiber, and the gut microbiome, with a particular focus on their potential implications in inflammation and cancer.

Enhancement of innate immunity in gingival epithelial cells by vitamin D and HDAC inhibitors

Introduction

The human host defense peptide LL-37 is a component of the innate immune defense mechanisms of the oral cavity against colonization by microbes associated with periodontal disease. We have previously shown that the active form of vitamin D, 1,25(OH)2D3, can induce the expression of LL-37 in gingival epithelial cells (GEC), and prevent the invasion and growth of periopathogenic bacteria in these cells. Further, experimental vitamin D deficiency resulted in increased gingival inflammation and alveolar bone loss. Epidemiological studies have shown associations between vitamin D deficiency and periodontal disease in humans, suggesting application of vitamin D could be a useful therapeutic approach. Further, since we have shown the local activation of vitamin D by enzymes expressed in the GEC, we hypothesized that we could observe this enhancement with the stable, and inexpensive inactive form of vitamin D, which could be further increased with epigenetic regulators.

Methods

We treated 3-dimensional primary cultures of GEC topically with the inactive form of vitamin D, in the presence and absence of selected histone deacetylase (HDAC) inhibitors. LL-37 mRNA levels were quantified by quantitative RT-PCR, and inhibition of invasion of bacteria was measured by fluorescence microscopy.

Results

Vitamin D treatment led to an induction of LL-37 mRNA levels, as well as an inhibition of pro-inflammatory cytokine secretion. This effect was further enhanced by HDAC inhibitors, most strongly when the HDAC inhibitor, phenyl butyrate (PBA) was combined with Vitamin D3. This was observed both in solution and in a prototype gel formulation using sodium butyrate. Finally, this combination treatment led to an increase in the antimicrobial activity against infection by Porphyromonas gingivalis and Filifactor alocis, bacteria associated with periodontal lesions, as well as herpes simplex virus, which has also been shown to be associated with periodontal lesions.

Conclusions

Our results demonstrate that a combination of inactive vitamin D and sodium butyrate could be developed as a safe treatment for periodontal disease.

Disease pathogenesis and barrier functions regulated by group 3 innate lymphoid cells

The mucosal surface is in constant contact with foreign antigens and is regulated by unique mechanisms that are different from immune responses in the peripheral organs. For the last several decades, only adaptive immune cells such as helper T (Th) cells, Th1, Th2, or Th17 were targeted to study a wide variety of immune responses in the mucosal tissues. However, since their discovery, innate lymphoid cells (ILCs) have been attracting attention as a unique subset of immune cells that provide border defense with various functions and tissue specificity. ILCs are classified into different groups based on cell differentiation and functions. Group 3 innate lymphoid cells (ILC3s) are particularly in close proximity to mucosal surfaces and therefore have the opportunity to be exposed to a variety of bacteria including pathogenic bacteria. In recent years, studies have also provided much evidence that ILC3s contribute to disease pathogenesis as well as the defense of mucosal surfaces by rapidly responding to pathogens and coordinating other immune cells. As the counterpart of helper T cells, ILC3s together with other ILC subsets establish the immune balance between adaptive and innate immunity in protecting us from invasion or encounter with non-self-antigens for maintaining a complex homeostasis. In this review, we summarize recent advances in our understanding of ILCs, with a particular focus on the function of ILC3s in their involvement in bacterial infection and disease pathogenesis.

Compromised NHE8 Expression Is Responsible for Vitamin D-Deficiency Induced Intestinal Barrier Dysfunction

Objectives: Vitamin D (VitD) and Vitamin D receptor (VDR) are suggested to play protective roles in the intestinal barrier in ulcerative colitis (UC). However, the underlying mechanisms remain elusive. Evidence demonstrates that Na+/H+ exchanger isoform 8 (NHE8, SLC9A8) is essential in maintaining intestinal homeostasis, regarded as a promising target for UC therapy. Thus, this study aims to investigate the effects of VitD/VDR on NHE8 in intestinal protection. Methods: VitD-deficient mice, VDR-/- mice and NHE8-/- mice were employed in this study. Colitis mice were established by supplementing DSS-containing water. Caco-2 cells and 3D-enteroids were used for in vitro studies. VDR siRNA (siVDR), VDR over-expression plasmid (pVDR), TNF-α and NF-κb p65 inhibitor QNZ were used for mechanical studies. The expression of interested proteins was detected by multiple techniques. Results: In colitis mice, paricalcitol upregulated NHE8 expression was accompanied by restoring colonic mucosal injury. In VitD-deficient and VDR-/- colitis mice, NHE8 expression was compromised with more serious mucosal damage. Noteworthily, paricalcitol could not prevent intestinal barrier dysfunction and histological destruction in NHE8-/- mice. In Caco-2 cells and enteroids, siVDR downregulated NHE8 expression, further promoted TNF-α-induced NHE8 downregulation and stimulated TNF-α-induced NF-κb p65 phosphorylation. Conversely, QNZ blocked TNF-α-induced NHE8 downregulation in the absence or presence of siVDR. Conclusions: Our study indicates depressed NHE8 expression is responsible for VitD-deficient-induced colitis aggravation. These findings provide novel insights into the molecular mechanisms of VitD/VDR in intestine protection in UC.

Polymorphism but not methylation status in the vitamin D receptor gene contributes to oral mucositis in children

OBJECTIVE

To investigate the relationship between the polymorphisms rs1544410 (BsmI), rs2228570 (FokI) and rs731236 (TaqI) and DNA methylation status in the VDR gene (vitamin D receptor) with oral mucositis (OM) in oncopaediatric patients treated with methotrexate (MTX®).

METHODS

The population comprised healthy patients with haematological malignancies aged between 5 and 19 years. An evaluation of oral conditions was performed using the Oral Assessment Guide. Demographic, clinical, biochemical and haematological data were obtained from medical records. Genomic DNA from oral mucosal cells was used for the analysis of polymorphisms (n = 102) (PCR-restriction fragment length polymorphism) and DNA methylation (n = 81) (methylation-specific PCR).

RESULTS

Males predominated (57.8%), and the mean age was 10.3 years (±4.7). OM affected 84.3% of patients, of which 53.1% developed severe oral mucositis (SOM). Patients with OM had lower platelet and leukocyte counts (p < 0.05). The G allele of rs1544410 (p = 0.040) and the CT genotype of rs2228570 polymorphisms were associated with SOM (p = 0.038). A partially methylated status in the VDR promoter was found in all patients.

CONCLUSION

OM is associated with lower leukocyte and platelet counts. SOM is associated with the rs1544410 and rs2228570 polymorphisms. The methylation status of the VDR is not associated with inflammation or exposure to MTX®.

Association of vitamin D receptor gene polymorphism with the risk of sepsis: A systematic review and meta-analysis

BACKGROUND

To investigate the association between sepsis and the vitamin D receptor (VDR) gene polymorphisms.

METHODS

Databases including PubMed, Cochrane Library, EMbase, CNKI, Wanfang Data, and VIP Data were systematically searched. The association was assessed using odds ratios (ORs), and 95% confidence intervals (CIs). The statistical tests were performed using Review Manager 5.4.

RESULTS

We identified a total of 5 studies. The relationship between VDR gene polymorphisms (Apa I, Bsm I, Taq I, and Fok I), and incidence of sepsis was investigated. The results of this meta-analysis showed that the allelic contrast model (F vs f, P = .03, OR = 0.65, 95% CI = 0.44-0.95), dominant genetic model (FF vs Ff + ff, P = .02, OR = 0.53, 95% CI = 0.30-0.91), and codominance genetic model (FF vs ff, P = .03, OR = 0.39, 95% CI = 0.16-0.91) of VDR Fok I locus increased the risk of sepsis, and the lack of association between the VDR Fok I gene polymorphism and the risk assessment of sepsis, based on the ethnic subgroup analysis, might be attributable to the small sample size. The risk of sepsis with Apa I, Bsm I, and Taq I did not appear to be correlated.

CONCLUSION SUBSECTIONS

This meta-analysis revealed that the VDR Fok I polymorphism is closely associated with the susceptibility to sepsis, and patients with sepsis have lower 25-hydroxyvitamin D levels. VDR Fok I gene mutations may change the risk of sepsis.

Vitamin D status, vitamin D receptor gene polymorphism, and haplotype in patients with cutaneous leishmaniasis: Correlation with susceptibility and parasite load index

BACKGROUND

CL endemicity was reported worldwide including in Saudi Arabia, imposing a major challenge on the health authorities. Vitamin D and its receptor (VDR) are key modulators of the immune response where the VDR is expressed. A remarkable lack of data exists in humans about the contribution of vitamin D and polymorphisms of the VDR gene in protozoan infections, especially cutaneous leishmaniasis (CL).

OBJECTIVE

This is the first work conducted to assess the relationship between vitamin D status, polymorphisms of the VDR gene (BsmI, ApaI, TaqI, and FokI), and VDR haplotype with parasite tissue load and susceptibility to CL.

METHODS

Fifty-two patients with confirmed CL (21 patients receiving vitamin D medication and 31 patients not receiving it) and 46 control subjects participated in this cross-sectional investigation. VDR genotyping was determined by restriction fragment length polymorphism analysis. Serum levels of 25-OH vitamin D were assessed using the ELISA method in all participants. The skin biopsy quantified the parasite load based on the Ridley parasitic index.

RESULTS

The mean serum level of 25-OH vitamin D in CL patients who were not receiving vitamin D therapy was significantly lower compared to CL patients on vitamin D therapy and controls (p <0.001 for both) and CL patients with no history of vitamin D therapy had a significantly higher frequency of vitamin D deficiency compared to CL patients on vitamin D therapy and controls (p < 0.05). Compared to CL patients with no history of vitamin D therapy, CL patients receiving vitamin D therapy had a significantly lower mean size of the lesion and RPI (p = 0.02, .03 respectively). The frequency of genotype "aa" and its "a" allele in ApaI SNP of VDR was significantly lower in CL patients compared to controls (p = 0.006 and 0.03 respectively). However, patients with CL had a considerably greater frequency of the "A" allele than the controls (p = 0.03), suggesting its role in CL susceptibility. There was no statistically significant difference between the two groups in the genotype and allele frequency distributions of BsmI, TaqI, and FokI (p > 0.05). When compared to controls, CL cases had a considerably greater frequency of the "B-A-T-F" haplotype (p = 0.04), and a significantly lower frequency of the "B-a-T-F" haplotype (p = 0.01) suggesting that these haplotypes may have the potential susceptibility or protection against CL respectively. The "Aa" genotype in ApaI SNP of VDR had considerably lower levels of vitamin D with higher parasite load compared to the "AA" and: aa" genotypes (p = 0.02,0.02 respectively). A significant negative correlation was found between the parasite load and 25-OH vitamin D levels (r2 = -0.53, p< 0.001).

CONCLUSIONS

According to these findings, vitamin D levels and "ApaI" VDR gene polymorphisms could affect the parasite load and susceptibility to infection, whereas BsmI, FokI, and TaqI polymorphisms did not. Correction of vitamin D levels may aid in CL management.

Low Vitamin K and Vitamin D Dietary Intake in Patients with Inflammatory Bowel Diseases

The inadequate dietary intake of Vitamin D and Vitamin K is an easily reversible factor favoring IBD-associated bone loss, but data on Vitamin K are lacking. A 28-item quantitative food frequency questionnaire was administered to 193 IBD patients (89 Crohn’s disease and 104 ulcerative colitis), and 199 controls. Patients’ demographics, clinical and laboratory findings were analyzed in relation to recommended daily allowances. VitD intake was inadequate both in the IBD and control patients (8.3 ± 4.5 µg/day in IBD, 53.1% RDA, and 9.7 ± 5.9 µg/day, 63.2% RDA, respectively). Conversely, the mean ViK intake was less than adequate in IBD, at 116.7 ± 116.3 µg/day (78.7% RDA), and high in controls, at 203.1 ± 166.9 µg/day (138.8% RDA). Nonetheless, due to marked inter-individual differences, diets were severely lacking VitK in 40% of UC and 49% of CD patients, more so in females and those with active disease. The intake of Vit D was non-significantly lower in colitis than that in Crohn’s disease (7.9 vs. 8.7 µg/day). The opposite was observed for VitK (123.5 vs. 107.0 µg/day). Thus, the diet lacks the micronutrients involved in bone wellbeing in a large proportion of IBD patients. While VitD supplementation is the rule, VitK shortages need proactive nutritional intervention.

Association of zinc deficiency with infectious complications in pediatric hematopoietic stem cell transplantation patients

BACKGROUND

Zinc plays essential roles in immune function and epithelial integrity. Patients undergoing hematopoietic stem cell transplantation (HSCT) often have low plasma zinc levels because of poor intake and diarrhea. We hypothesized that patients with zinc deficiency before HSCT had worse infectious complications after HSCT compared with patients with normal zinc levels. Citrulline, a marker of intestinal integrity, was also hypothesized to be lower in patients with zinc deficiency.

PATIENTS AND METHODS

Thirty patients undergoing HSCT at Ramathibodi Hospital during March 2020-September 2021 were enrolled. Blood samples for plasma zinc and citrulline were collected during the HSCT period. The 14- and 90-day outcomes after HSCT were prospectively recorded.

RESULTS

Twelve of 30 (40%) patients had zinc deficiency before HSCT. Zinc-deficient patients were younger (median (interquartile range): 6 (8.8) vs 13 (5.8) years old; p = 0.017). Zinc levels tended to increase after admission in both groups. Patients with zinc deficiency had lower citrulline levels than those with normal zinc levels. Citrulline levels decreased in both groups after stem cell infusion, and the level was not significantly different between the two groups. Zinc-deficient patients had a higher rate of bacterial infection within 90 days after HSCT than those with normal zinc levels (6 in 12 patients (50.0%) vs 1 in 18 patients (5.6%); odds ratio [OR]: 17.0; 95% confidence interval [CI]: 1.68-171.70; p = 0.016). This remained significant after adjustments for age (adjusted OR: 12.31; 95% CI: 1.084-139.92; p = 0.043).

CONCLUSION

The prevalence of zinc deficiency in pediatric patients undergoing HSCT was high. Zinc-deficient patients had lower citrulline levels and higher incidence of bacterial infection after HSCT. However, citrulline level was not different between patients with and without bacterial infections. It is worth to investigate whether zinc supplementation before HSCT can reduce bacterial infection after HSCT.

Manipulation of the diet-microbiota-brain axis in Alzheimer's disease

Several studies investigating the pathogenesis of Alzheimer's disease have identified various interdependent constituents contributing to the exacerbation of the disease, including Aβ plaque formation, tau protein hyperphosphorylation, neurofibrillary tangle accumulation, glial inflammation, and the eventual loss of proper neural plasticity. Recently, using various models and human patients, another key factor has been established as an influential determinant in brain homeostasis: the gut-brain axis. The implications of a rapidly aging population and the absence of a definitive cure for Alzheimer's disease have prompted a search for non-pharmaceutical tools, of which gut-modulatory therapies targeting the gut-brain axis have shown promise. Yet multiple recent studies examining changes in human gut flora in response to various probiotics and environmental factors are limited and difficult to generalize; whether the state of the gut microbiota in Alzheimer's disease is a cause of the disease, a result of the disease, or both through numerous feedback loops in the gut-brain axis, remains unclear. However, preliminary findings of longitudinal studies conducted over the past decades have highlighted dietary interventions, especially Mediterranean diets, as preventative measures for Alzheimer's disease by reversing neuroinflammation, modifying the intestinal and blood-brain barrier (BBB), and addressing gut dysbiosis. Conversely, the consumption of Western diets intensifies the progression of Alzheimer's disease through genetic alterations, impaired barrier function, and chronic inflammation. This review aims to support the growing body of experimental and clinical data highlighting specific probiotic strains and particular dietary components in preventing Alzheimer's disease via the gut-brain axis.

Does Vitamin D Insufficiency Influence Prebiotic Effect on Calcium Absorption and Bone Retention?

Higher calcium (Ca) absorption would partially compensate for Ca intake below requirements for bone health. Previously, we found that GOS/FOS prebiotic mixture (PM) increases Ca absorption in the colon and retention in bone. Ca absorption and retention are regulated by vitamin D (VD). Hence, it is relevant to explore whether VD insufficiency influences the effect of the PM in the colon. The effect of the PM on Ca, phosphate (IP), and magnesium (Mg) absorption and retention under conditions of VD sufficiency and insufficiency (VDInsuff) was compared using a preclinical model of VDInsuff and low bone mass. Ovariectomized rats were fed isocaloric semisynthetic diets according to AIN-93 M. The diets varied in Ca (0.5% or 0.3%), VD [100 IU% (+ D) or 0 IU% (- D)], and PM (2.5% or 0%) content. The following eight groups were studied: + D0.5; + D0.3; + DPM0.5; + DPM0.3; - D0.5; - D0.3; - DPM0.5; and - DPM0.3. Irrespective of Ca content, VDInsuff did not affect the prebiotic effect of the PM on caecum pH, lactobacillus colony growth, or Mg absorption but significantly decreased its effect on colonic crypt length and cell/crypt and Ca and IP absorption. The PM failed to counterbalance the pro-inflammatory effect of VDInsuff. Moreover, bone retention i.e., bone mineral content and density, bone volume, and bone quality parameters were significantly lower (p < 0.05) and bone turnover significantly was higher (p < 0.05). Although the PM is a useful tool to improve mineral absorption and bone retention, it would seem important to monitor VD nutritional status to ensure the full prebiotic effect in the large intestine.

Long-Term Vitamin D Deficiency Results in the Inhibition of Cell Proliferation and Alteration of Multiple Gastric Epithelial Cell Lineages in Mice

Over one billion people globally are vitamin D (VD) deficient. Studies on the biological roles of VD are numerous but very little on the stomach. This project aims to understand how gastric homeostasis is affected by VD deficiency caused by prolonged exposure to darkness alone or combined with VD deficient diet. Three groups of C57/BL6 mice were subjected to different light exposure conditions and diets for 12 months (n = 8−12/group): control—12 h/12 h light/dark SDL (Standard Diet/Light), 24 h dark SDD (Standard Diet/Dark), and 24 h dark VDD (VD deficient diet/Dark). Stomach samples were collected for different multi-label lectin-/immuno-histochemical and qRT-PCR analyses, and the serum for LC-MS-MS. We found that the membrane VD receptor is expressed widely in the stomach when compared to nuclear VD receptors. Compared to SDL, VDD mice developed mucous cell expansion with increased mucins-mRNA (3.27 ± 2.73 (p < 0.05)) increased apoptotic cells, 15 ± 7 (p ≤ 0.001)); decreased cell proliferation, 4 ± 4 (p < 0.05)) and decreased acid secretion 33 ± 2 μEq/kg (p ≤ 0.0001)). Interestingly, mice exposed to full darkness developed mild VD deficiency with higher VD epimer levels: 11.9 ± 2.08 ng/mL (p ≤ 0.0001)), expansion in zymogenic cell number (16 ± 3 (p ≤ 0.01)), and a reduction in acid secretion (18 ± 2 μEq/kg (p ≤ 0.0001)). In conclusion, changes in light exposure or VD levels have serious physiological effects on the gastric mucosa, which should be considered during the management of gastric disorders.

The Role of Microbiome in Brain Development and Neurodegenerative Diseases

Hundreds of billions of commensal microorganisms live in and on our bodies, most of which colonize the gut shortly after birth and stay there for the rest of our lives. In animal models, bidirectional communications between the central nervous system and gut microbiota (Gut-Brain Axis) have been extensively studied, and it is clear that changes in microbiota composition play a vital role in the pathogenesis of various neurodevelopmental and neurodegenerative disorders, such as Autism Spectrum Disorder, Alzheimer's disease, Parkinson's disease, Multiple Sclerosis, Amyotrophic Lateral Sclerosis, anxiety, stress, and so on. The makeup of the microbiome is impacted by a variety of factors, such as genetics, health status, method of delivery, environment, nutrition, and exercise, and the present understanding of the role of gut microbiota and its metabolites in the preservation of brain functioning and the development of the aforementioned neurological illnesses is summarized in this review article. Furthermore, we discuss current breakthroughs in the use of probiotics, prebiotics, and synbiotics to address neurological illnesses. Moreover, we also discussed the role of boron-based diet in memory, boron and microbiome relation, boron as anti-inflammatory agents, and boron in neurodegenerative diseases. In addition, in the coming years, boron reagents will play a significant role to improve dysbiosis and will open new areas for researchers.

Role of Bile Acids and Nuclear Receptors in Acupuncture in Improving Crohn's Disease

Nuclear receptors (NRs) are ligand-dependent transcription factors that regulate the transcription of target genes. Bile acids (BAs) can be used as effector molecules to regulate physiological processes in the gut, and NRs are important receptors for bile acid signaling. Relevant studies have shown that NRs are closely related to the occurrence of Crohn's disease (CD). Although the mechanism of NRs in CD has not been clarified completely, growing evidence shows that NRs play an important role in regulating intestinal immunity, mucosal barrier, and intestinal flora. NRs can participate in the progress of CD by mediating inflammation, immunity, and autophagy. As the important parts of traditional Chinese medicine (TCM) therapy, acupuncture and moxibustion in the treatment of CD curative mechanism can get a lot of research support. At the same time, acupuncture and moxibustion can regulate the changes of related NRs. Therefore, to explore whether acupuncture can regulate BA circulation and NRs expression and then participate in the disease progression of CD, a new theoretical basis for acupuncture treatment of CD is provided.

Efficacy and Safety of High-dose Cholecalciferol in Patients With Inflammatory Bowel Disease Receiving Infliximab

OBJECTIVE

Vitamin D deficiency is prevalent in patients with inflammatory bowel disease (IBD). The goal of this study was to assess the efficacy and safety of high-dose, interval cholecalciferol administration in patients with IBD receiving infliximab.

METHODS

This prospective, longitudinal, open-label study enrolled pediatric and young adult patients with IBD and vitamin D deficiency. Subjects received 50,000 IU every 4 to 5 weeks (n = 11) or 100,000 IU every 6 to 8 weeks (n = 32) of oral cholecalciferol for 1 year. Dosing was directly observed and administered in conjunction with infliximab infusions. The primary endpoint was vitamin D sufficiency, defined as a 25-hydroxy-vitamin D (25-OHD) level ≥30 ng/mL.

RESULTS

Forty-three participants constituted the primary analysis population. 25-OHD levels reached steady-state after the third dose, and mean increases in 25-OHD levels were 8 vs. 4.5 ng/mL in the 100,000 IU vs. 50,000 IU treatment groups, respectively. Only 43.8% of patients receiving 100,000 IU and 18.2% of patients receiving 50,000 IU achieved sufficiency. There was no difference in the 25-OHD level responsiveness in patients with Crohn disease versus those with ulcerative colitis (P = 0.72). There was no correlation between 25-OHD levels and clinical disease activity in patients with Crohn disease (P = 0.85) or ulcerative colitis (P = 0.24).

CONCLUSIONS

Supplementation with cholecalciferol was well-tolerated and direct observation is a promising paradigm for ensuring compliance with therapy. Patients with IBD, however, appear to require high doses of cholecalciferol, with less than half of patients (37% overall) achieving vitamin D sufficiency. Additional studies are necessary to determine the optimal treatment regimens.

Vitamin D receptor upregulates tight junction protein claudin-5 against colitis-associated tumorigenesis

Tight junctions are essential for barrier integrity, inflammation, and cancer. Vitamin D and the vitamin D receptor (VDR) play important roles in colorectal cancer (CRC). Using the human CRC database, we found colonic VDR expression was low and significantly correlated with a reduction of Claudin-5 mRNA and protein. In the colon of VDR^ΔIEC mice, deletion of intestinal VDR led to lower protein and mRNA levels of Claudin-5. Intestinal permeability was increased in the VDR^-/- colon cancer model. Lacking VDR and a reduction of Claudin-5 are associated with an increased number of tumors in the VDR^-/- and VDR^ΔIEC mice. Furthermore, gain and loss functional studies have identified CLDN-5 as a downstream target of VDR. We identified the Vitamin D response element (VDRE) binding sites in a reporter system showed that VDRE in the Claudin-5 promoter is required for vitamin D₃-induced Claudin-5 expression. Conditional epithelial VDR overexpression protected against the loss of Claudin-5 in response to inflammation and tumorigenesis in vivo. We also reported fecal VDR reduction in a colon cancer model. This study advances the understanding of how VDR regulates intestinal barrier functions in tumorigenesis and the possibility for identifying new biomarker and therapeutic targets to restore VDR-dependent functions in CRC.

Vitamin D Receptor Influences Intestinal Barriers in Health and Disease

Vitamin D receptor (VDR) executes most of the biological functions of vitamin D. Beyond this, VDR is a transcriptional factor regulating the expression levels of many target genes, such as genes for tight junction proteins claudin-2, -5, -12, and -15. In this review, we discuss the progress of research on VDR that influences intestinal barriers in health and disease. We searched PubMed and Google Scholar using key words vitamin D, VDR, tight junctions, cancer, inflammation, and infection. We summarize the literature and progress reports on VDR regulation of tight junction distribution, cellular functions, and mechanisms (directly or indirectly). We review the impacts of VDR on barriers in various diseases, e.g., colon cancer, infection, inflammatory bowel disease, and chronic inflammatory lung diseases. We also discuss the limits of current studies and future directions. Deeper understanding of the mechanisms by which the VDR signaling regulates intestinal barrier functions allow us to develop efficient and effective therapeutic strategies based on levels of tight junction proteins and vitamin D/VDR statuses for human diseases.

Course of vitamin D levels before and after liver transplantation in pediatric patients

BACKGROUND

25-hydroxy VD insufficiency is known in children undergoing LT but the serial post-transplant VD course and supplementation modalities in the peri-transplant period are lacking. We aimed to determine the pre-VD status and the post-transplant VD status course following VD supplementation and to elucidate its relationship with post-transplant outcome parameters such as infection and survival.

METHODS

Pre- and post-VD levels were monitored in parallel with interventions to adjust VD levels in LT patients. VD status was categorized as circulating levels <30-21 ng/ml (insufficiency), 20-10 ng/ml (deficiency), and <10 ng/ml (severe deficiency). Patients received stoss (300000IU) VD3 within the pretransplant period if serum levels were <20 ng/ml.

RESULTS

135 transplanted children were included. The age at LT was 22 months (IQR: 8-60). The pretransplant median VD level was 14 ng/ml. Despite stoss dose, post-transplant median VD level was 1.8 ng/ml (day one), 4 ng/ml (week one), 19 ng/ml (month one), 33 ng/ml (month three), 38 ng/ml (months 6-12), and 40 ng/ml (month 24). After 6 months, VD status reached >30 ng/ml in 98% of patients. Only at pre-LT, higher infection rate (18.7%) in the severe VD deficiency group was observed compared to the VD deficiency group (2.9%, p = .04). Survival was not affected by serum VD levels.

CONCLUSION

VD levels fell substantially after LT but are rectifiable by stoss dose, which was well tolerated. Only the infection rate was associated with the VD status.

The effects of cardiovascular and orthopaedic surgery on vitamin concentrations: a narrative review of the literature and mechanisms of action

Given the rise in worldwide chronic diseases, supplemented by an aging population, the volume of global major surgeries, encompassing cardiac and orthopedic procedures is anticipated to surge significantly. Surgical trauma can be accompanied by numerous postoperative complications and metabolic changes. The present review summarized the results from studies assessing the effects of orthopedic and cardiovascular surgery on vitamin concentrations, in addition to exploring the possible mechanisms associated with changes in concentrations. Studies have revealed a potentially severe depletion in plasma/serum concentrations of numerous vitamins following these surgeries acutely. Vitamins C, D and B1 appear particularly vulnerable to significant depletions, with vitamin C and D depletions consistently transpiring into inadequate and deficient concentrations, respectively. The possible multifactorial mechanisms impacting postoperative vitamin concentrations include changes in hemodilution and vitamin utilization, redistribution, circulatory transport and absorption. For a majority of vitamins, there has been a lack of investigation into the effects of both, cardiac and orthopedic surgery. Additionally, studies were predominantly restricted to short-term postoperative investigations, primarily performed within the first postoperative week of surgery. Overall, results indicated that further examination is necessary to determine the severity and clinical significance of the possible depletions in vitamin concentrations that ensue cardiovascular and orthopedic surgery.

Role of Food Antioxidants in Modulating Gut Microbial Communities: Novel Understandings in Intestinal Oxidative Stress Damage and Their Impact on Host Health

Dietary components have an important role on the structure and function of host gut microbial communities. Even though, various dietary components, such as carbohydrates, fats, proteins, fibers, and vitamins, have been studied in depth for their effect on gut microbiomes, little attention has been paid regarding the impact of several food antioxidants on the gut microbiome. The long-term exposure to reactive oxygen species (ROS) can cause microbial dysbiosis which leads to numerous intestinal diseases such as microbiota dysbiosis, intestinal injury, colorectal cancers, enteric infections, and inflammatory bowel diseases. Recently, it has been shown that the food derived antioxidant compounds might protect the host from intestinal oxidative stress via modulating the composition of beneficial microbial species in the gut. The present review summarizes the impact of food antioxidants including antioxidant vitamins, dietary polyphenols, carotenoids, and bioactive peptides on the structure as well as function of host gut microbial communities. Several in vitro, animal model, and clinical studies indicates that food antioxidants might modify the host gut microbial communities and their health status. However, still further clarification is needed as to whether changes in certain microbial species caused by food additives may lead to changes in metabolism and immune function.

Differences in Dietary Patterns of Adolescent Patients with IBD

Inflammatory bowel disease (IBD) includes Crohn’s disease (CD) and ulcerative colitis (UC). The prevalence of both in pediatric populations has been constantly increasing. This study aimed to analyze the diet of adolescent patients with IBD in comparison to healthy controls and the current dietary standards for the Polish population to further their optimal supplementation regimen. The study group consisted of 53 patients (21 girls and 32 boys) with IBD (CD: n = 27; UC: n = 26) at a mean age of 15.4 ± 2.4 and 14.7 ± 2.2, years for girls and boys, respectively. The control group (CG) consisted of 20 patients, and 72 h of recall diaries on nutrition were collected. The nutritional data were analyzed in the Dieta 6D dietary program. When compared to Polish dietary standards, the largest differences girls with IBD and boys with IBD were found for the intake of energy (61.9 and 71.9%), iodine (61.9 and 62.6%), folates (76.2 and 87.5%), vitamin D (100 and 96.9%), potassium (61.9 and 59.4%), and calcium (85.7 and 93.8%). The overconsumption of saturated fatty acids (SFA) (61.9 and 56.3%) and sodium (76.2 and 90.6%) in girls and boys, respectively, was noted. In relation to girls with CG, girls with IBD showed a significantly higher intake of energy (1751. 3 vs. 1558.6 p = 0.0224), total protein (71.3 vs. 56.2 p = 0.0217), animal protein (47.8 vs. 34.5 p = 0.0183), total carbohydrates (237.3 vs. 196.1 p = 0.0442), and assimilable carbohydrates (219.8 vs. 180.5 p = 0.7921). Boys in the CG consumed significantly more calcium (851.8 vs. 432 p = 0.0006), phosphorus (1024.3 vs. 1357.5 p = 0.0431), lactose (11.6 vs. 6.1 p = 0.0016), and riboflavin (1.7 vs. 1.3 p = 0.0123) compared to boys with IBD. Dietician care should therefore be mandatorily provided alongside outpatient care. Based on our results, we suggest that supplementation with the selected components be considered.

The Correlation between Vitamin D Levels and the Risk of Postoperative Recurrence in Crohn's Disease

BACKGROUND AND AIMS

Vitamin D deficiency has been associated with disease activity in Crohn's disease (CD). We assessed whether there is a correlation between vitamin D levels and the risk of postoperative recurrence in CD.

METHODS

CD patients who underwent surgery were identified from a prospectively maintained database at the University of Chicago. The primary endpoint was the correlation of serum 25-hydroxy vitamin D levels measured at 6-12 months after surgery and the proportion of patients in endoscopic remission, defined as a simple endoscopic score for CD of 0. Clinical, biological (C-reactive protein), and histologic recurrences were also studied.

RESULTS

Among a total of 89 patients, 17, 46, and 26 patients had vitamin D levels of <15, 15-30, and >30 ng/mL, respectively. Patients with higher vitamin D levels were significantly more likely to be in endoscopic remission compared to those with lower levels (23, 42, and 67% in ascending tertile order; p = 0.028). On multivariate analysis, vitamin D >30 ng/mL (odds ratio [OR] 0.22, 95% confidence interval [CI] 0.07-0.66, p = 0.006) and anti-tumor necrosis factor agent treatment (OR 0.25, 95% CI 0.08-0.83, p = 0.01) were associated with reduced risk of endoscopic recurrence. Rates of clinical, biological, and histologic remission trended to be higher in patients with higher vitamin D levels (p = 0.17, 0.55, 0.062, respectively).

CONCLUSION

In the present study, higher vitamin D level was associated with lower risk of postoperative endoscopic CD recurrence. Further, studies are warranted to assess the role of vitamin D in postoperative CD recurrence.

Gastrointestinal symptoms, pathophysiology, and treatment in COVID-19

The novel coronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has emerged and is responsible for the Coronavirus Disease 2019 global pandemic. Coronaviruses, including SARS-CoV-2, are strongly associated with respiratory symptoms during infection, but gastrointestinal symptoms, such as diarrhea, vomiting, nausea, and abdominal pain, have been identified in subsets of COVID-19 patients. This article focuses on gastrointestinal symptoms and pathophysiology in COVID-19 disease. Evidence suggests that the gastrointestinal tract could be a viral target for SARS-CoV-2 infection. Not only is the SARS-CoV-2 receptor ACE2 highly expressed in the GI tract and is associated with digestive symptoms, but bleeding and inflammation are observed in the intestine of COVID-19 patients. We further systemically summarize the correlation between COVID-19 disease, gastrointestinal symptoms and intestinal microbiota. The potential oral-fecal transmission of COVID-19 was supported by viral RNA and live virus detection in the feces of COVID-19 patients. Additionally, the viral balance in the GI tract could be disordered during SARS-CoV-2 infection which could further impact the homeostasis of the gut microbial flora. Finally, we discuss the clinical and ongoing trials of treatments/therapies, including antiviral drugs, plasma transfusion and immunoglobulins, and diet supplementations for COVID-19. By reviewing the pathogenesis of SARS-CoV-2 virus, and understanding the correlation among COVID-19, inflammation, intestinal microbiota, and lung microbiota, we provide perspective in prevention and control, as well as diagnosis and treatment of the COVID-19 disease.

Phosphate, Microbiota and CKD

Phosphate is a key uremic toxin associated with adverse outcomes. As chronic kidney disease (CKD) progresses, the kidney capacity to excrete excess dietary phosphate decreases, triggering compensatory endocrine responses that drive CKD-mineral and bone disorder (CKD-MBD). Eventually, hyperphosphatemia develops, and low phosphate diet and phosphate binders are prescribed. Recent data have identified a potential role of the gut microbiota in mineral bone disorders. Thus, parathyroid hormone (PTH) only caused bone loss in mice whose microbiota was enriched in the Th17 cell-inducing taxa segmented filamentous bacteria. Furthermore, the microbiota was required for PTH to stimulate bone formation and increase bone mass, and this was dependent on bacterial production of the short-chain fatty acid butyrate. We review current knowledge on the relationship between phosphate, microbiota and CKD-MBD. Topics include microbial bioactive compounds of special interest in CKD, the impact of dietary phosphate and phosphate binders on the gut microbiota, the modulation of CKD-MBD by the microbiota and the potential therapeutic use of microbiota to treat CKD-MBD through the clinical translation of concepts from other fields of science such as the optimization of phosphorus utilization and the use of phosphate-accumulating organisms.

Oral microbiota and vitamin D impact on oropharyngeal squamous cell carcinogenesis: a narrative literature review

An emerging body of research is revealing the microbiota pivotal involvement in determining the health or disease state of several human niches, and that of vitamin D also in extra-skeletal regions. Nevertheless, much of the oral microbiota and vitamin D reciprocal impact in oropharyngeal squamous cell carcinogenesis (OPSCC) is still mostly unknown. On this premise, starting from an in-depth scientific bibliographic analysis, this narrative literature review aims to show a detailed view of the state of the art on their contribution in the pathogenesis of this cancer type. Significant differences in the oral microbiota species quantity and quality have been detected in OPSCC-affected patients; in particular, mainly high-risk human papillomaviruses (HR-HPVs), Fusobacterium nucleatum, Porphyromonas gingivalis, Pseudomonas aeruginosa, and Candida spp. seem to be highly represented. Vitamin D prevents and fights infections promoted by the above identified pathogens, thus confirming its homeostatic function on the microbiota balance. However, its antimicrobial and antitumoral actions, well-described for the gut, have not been fully documented for the oropharynx yet. Deeper investigations of the mechanisms that link vitamin D levels, oral microbial diversity and inflammatory processes will lead to a better definition of OPSCC risk factors for the optimization of specific prevention and treatment strategies.

The implications of vitamin D deficiency on COVID-19 for at-risk populations

Novel coronavirus disease 2019 (COVID-19) has spread to > 10 000 000 individuals in a short time. With no pharmacological agents successfully implemented to control the outbreak, the use of less invasive nonpharmacological agents, such as vitamin D, are increasingly being studied. This purpose of this article is to determine the current knowledge about the risk of COVID-19 development for populations at risk for vitamin D deficiency, including individuals living with overweight and obesity, those of older age, and racial or ethnic minorities. Despite the documented impact of vitamin D on viral disease prevention, many subgroups at risk for contracting COVID-19 are also known to have increased rates of vitamin D deficiency. Because vitamin D is most commonly obtained from sunlight, when interpreted alongside the stay-at-home orders, the importance of identifying safe approaches to obtain sufficient vitamin D is apparent. Furthermore, elucidating the cause-and-effect relationship between vitamin D and COVID-19, including optimal dosing for COVID-19 outcomes, is also warranted for immediate investigation.

Analysis of 1,25-Dihydroxyvitamin D3 Genomic Action Reveals Calcium-Regulating and Calcium-Independent Effects in Mouse Intestine and Human Enteroids

Although vitamin D is critical for the function of the intestine, most studies have focused on the duodenum. We show that transgenic expression of the vitamin D receptor (VDR) only in the distal intestine of VDR null mice (KO/TG mice) results in the normalization of serum calcium and rescue of rickets. Although it had been suggested that calcium transport in the distal intestine involves a paracellular process, we found that the 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-activated genes in the proximal intestine associated with active calcium transport (Trpv6, S100g, and Atp2b1) are also induced by 1,25(OH)2D3 in the distal intestine of KO/TG mice. In addition, Slc30a10, encoding a manganese efflux transporter, was one of the genes most induced by 1,25(OH)2D3 in both proximal and distal intestine. Both villus and crypt were found to express Vdr and VDR target genes. RNA sequence (RNA-seq) analysis of human enteroids indicated that the effects of 1,25(OH)2D3 observed in mice are conserved in humans. Using Slc30a10-/- mice, a loss of cortical bone and a marked decrease in S100g and Trpv6 in the intestine was observed. Our findings suggest an interrelationship between vitamin D and intestinal Mn efflux and indicate the importance of distal intestinal segments to vitamin D action.

The potential role of vitamin D supplementation as a gut microbiota modifier in healthy individuals

Vitamin D deficiency affects approximately 80% of individuals in some countries and has been linked with gut dysbiosis and inflammation. While the benefits of vitamin D supplementation on the gut microbiota have been studied in patients with chronic diseases, its effects on the microbiota of otherwise healthy individuals is unclear. Moreover, whether effects on the microbiota can explain some of the marked inter-individual variation in responsiveness to vitamin D supplementation is unknown. Here, we administered vitamin D to 80 otherwise healthy vitamin D-deficient women, measuring serum 25(OH) D levels in blood and characterizing their gut microbiota pre- and post- supplementation using 16S rRNA gene sequencing. Vitamin D supplementation significantly increased gut microbial diversity. Specifically, the Bacteroidetes to Firmicutes ratio increased, along with the abundance of the health-promoting probiotic taxa Akkermansia and Bifidobacterium. Significant variations in the two-dominant genera, Bacteroides and Prevotella, indicated a variation in enterotypes following supplementation. Comparing supplementation responders and non-responders we found more pronounced changes in abundance of major phyla in responders, and a significant decrease in Bacteroides acidifaciens in non-responders. Altogether, our study highlights the positive impact of vitamin D supplementation on the gut microbiota and the potential for the microbial gut signature to affect vitamin D response.

Vitamin D supplementation in pregnancy and early infancy in relation to gut microbiota composition and C. difficile colonization: implications for viral respiratory infections

In Canada and the US, the infant diet is supplemented with vitamin D via supplement drops or formula. Pregnant and nursing mothers often take vitamin D supplements. Since little is known about the impact of this supplementation on infant gut microbiota, we undertook a study to determine the association between maternal and infant vitamin D supplementation, infant gut microbiota composition and Clostridioides difficile colonization in 1,157 mother-infant pairs of the CHILD (Canadian Healthy Infant Longitudinal Development) Cohort Study over 2009-2012. Logistic and MaAsLin regression were employed to assess associations between vitamin D supplementation, and C. difficile colonization, or other gut microbiota, respectively. Sixty-five percent of infants received a vitamin D supplement. Among all infants, infant vitamin D supplementation was associated with a lower abundance of genus Megamonas (q = 0.01) in gut microbiota. Among those exclusively breastfed, maternal prenatal supplementation was associated with lower abundance of Bilophila (q = 0.01) and of Lachnospiraceae (q = 0.02) but higher abundance of Haemophilus (q = 0.02). There were no differences in microbiota composition with vitamin D supplementation among partially and not breastfed infants. Neither infant nor maternal vitamin D supplementation were associated with C. difficile colonization, after adjusting for breastfeeding status and other factors. However, maternal consumption of vitamin-D fortified milk reduced the likelihood of C. difficile colonization in infants (adjustedOR: 0.40, 95% CI: 0.19-0.82). The impact of this compositional difference on later childhood health, especially defense against viral respiratory infection, may go beyond the expected effects of vitamin D supplements and remains to be ascertained.

Vitamin D oral gel for prevention of radiation-induced oral mucositis: A randomized clinical trial

OBJECTIVES

The aim of this clinical trial is to evaluate the effectiveness of topical oral vitamin D gel in prevention of radiation-induced oral mucositis.

MATERIAL AND METHODS

A three-armed randomized controlled clinical trial on forty-five head and neck cancer patients was conducted. First group: conventional treatment. Second group: Topical oral vitamin D gel. Third group: topical oral vitamin D gel plus the conventional treatment. All the patients were examined clinically three and six weeks after the start of radiotherapy for pain and WHO mucositis score.

RESULTS

After 6 weeks of radiotherapy, (33.5%) the patients in control group developed high-grade severity of oral mucositis while the patients in the two-test groups "vitamin D group and combined therapy group" remained with low-grade severity or with complete remission. Mean pain scores showed a significant decrease in the combined therapy group and to a close degree in vitamin D group rather than the control group.

CONCLUSION

Topical oral vitamin D gel has a beneficial effect in lowering oral mucositis development and in reducing pain sensation during the radiation period especially when combined with conventional therapeutic agents.

Diet and Nutrients in Gastrointestinal Chronic Diseases

Diet and nutrition are known to play key roles in many chronic gastrointestinal diseases, regarding both pathogenesis and therapeutic possibilities. A strong correlation between symptomatology, disease activity and eating habits has been observed in many common diseases, both organic and functional, such as inflammatory bowel disease and irritable bowel syndrome. New different dietary approaches have been evaluated in order improve patients’ symptoms, modulating the type of sugars ingested, the daily amount of fats or the kind of metabolites produced in gut. Even if many clinical studies have been conducted to fully understand the impact of nutrition on the progression of disease, more studies are needed to test the most promising approaches for different diseases, in order to define useful guidelines for patients.

Gut instincts: vitamin D/vitamin D receptor and microbiome in neurodevelopment disorders

The gut microbiome regulates a relationship with the brain known as the gut–microbiota–brain (GMB) axis. This interaction is influenced by immune cells, microbial metabolites and neurotransmitters. Recent findings show gut dysbiosis is prevalent in autism spectrum disorder (ASD) as well as attention deficit hyperactivity disorder (ADHD). There are previously established negative correlations among vitamin D, vitamin D receptor (VDR) levels and severity of ASD as well as ADHD. Both vitamin D and VDR are known to regulate homeostasis in the brain and the intestinal microbiome. This review summarizes the growing relationship between vitamin D/VDR signalling and the GMB axis in ASD and ADHD. We focus on current publications and summarize the progress of GMB in neurodevelopmental disorders, describe effects and mechanisms of vitamin D/VDR in regulating the microbiome and synoptically highlight the potential applications of targeting vitamin D/VDR signalling in neurodevelopment disorders.

Vitamin D Receptor Protects Against Dysbiosis and Tumorigenesis via the JAK/STAT Pathway in Intestine

BACKGROUND & AIMS

Vitamin D exerts regulatory roles via vitamin D receptor (VDR) in mucosal immunity, host defense, and inflammation involving host factors and microbiome. Human Vdr gene variation shapes the microbiome and VDR deletion leads to dysbiosis. Low VDR expression and diminished vitamin D/VDR signaling are observed in colon cancer. Nevertheless, how intestinal epithelial VDR is involved in tumorigenesis through gut microbiota remains unknown. We hypothesized that intestinal VDR protects mice against dysbiosis via modulating the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway in tumorigenesis.

METHODS

To test our hypothesis, we used an azoxymethane/dextran sulfate sodium-induced cancer model in intestinal VDR conditional knockout (VDR^ΔIEC) mice, cell cultures, stem cell-derived colonoids, and human colon cancer samples.

RESULTS

VDR^ΔIEC mice have higher numbers of tumors, with the location shifted from the distal to proximal colon. Fecal microbiota analysis showed that VDR deletion leads to a bacterial profile shift from normal to susceptible carcinogenesis. We found enhanced bacterial staining in mouse and human tumors. Microbial metabolites from VDR^ΔIEC mice showed increased secondary bile acids, consistent with observations in human CRC. We further identified that VDR protein bound to the Jak2 promoter, suggesting that VDR transcriptionally regulated Jak2. The JAK/STAT pathway is critical in intestinal and microbial homeostasis. Fecal samples from VDR^ΔIEC mice activate the STAT3 signaling in human and mouse organoids. Lack of VDR led to hyperfunction of Jak2 in response to intestinal dysbiosis. A JAK/STAT inhibitor abolished the microbiome-induced activation of STAT3.

CONCLUSIONS

We provide insights into the mechanism of VDR dysfunction leading to dysbiosis and tumorigenesis. It indicates a new target: microbiome and VDR for the prevention of cancer.

Vitamin D3 modulates yellow catfish (Pelteobagrus fulvidraco) immune function in vivo and in vitro and this involves the vitamin D3/VDR-type I interferon axis

Vitamin D₃ (VD₃) has been shown to regulate immune function in mammals. 1,25-dihydroxyvitamin (1,25(OH)₂D₃) is the active form of vitamin D₃, which is also known as calcitriol. The current study investigated the immunomodulatory effects of 1,25(OH)₂D₃ on the innate immune response of yellow catfish (Pelteobagrus fulvidraco) after in vivo and in vitro immune challenge. The in vivo results showed that increasing dietary vitamin D₃ decreased mortality, enhanced the immune protective rate, and increased serum lysozyme, catalase and SOD activities in yellow catfish infected with Edwardsiella Ictaluri (p < 0.05). The in vitro results showed that 1,25(OH)₂D₃ (0, 1, 10, 100, 200 pM) dose-dependently attenuated the rate of apoptosis and production or reactive oxygen species and increased the phagocytic activity of head kidney macrophages stimulated with 10 mg/L lipopolysaccharide (LPS) and 100 mg/L of Poly(I:C) (p < 0.05). Real-time quantitative PCR results showed that increasing dietary vitamin D₃ content in vivo and increasing the level of 1,25(OH)₂D₃in vitro partially regulated the expression of VD₃/VDR-type I interferon axis genes (vdr, irf-3, ifn-a, jak1, stat1, ifi56 and ifp35) after immune challenge. These results indicated that vitamin D₃ content helped yellow catfish to resist oxidative stress and inflammation caused by immune challenge, and immunomodulation involved the VD₃/VDR-type I interferon action axis.

Vitamin D receptor (VDR) gene polymorphism and risk of rheumatoid arthritis (RA): systematic review and meta-analysis

Vitamin D is involved in immune system modulation as well as in calcium and bone homeostasis, hence plays a role in rheumatoid arthritis (RA) etiopathogenesis. A bulk of studies in different populations have assessed the association between the vitamin D receptor (VDR) gene polymorphisms and the risk of RA, reporting conflicting results. Therefore, we designed a meta-analysis to comprehensively evaluate the association of VDR gene polymorphisms and RA risk. All potential studies reporting the association between VDR gene polymorphisms and susceptibility to RA published till February 2020 were retrieved through systematic search of database, including Scopus and MEDLINE. Strength of pooled association was determined through calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analysis was performed by stratifying the studies by population type. This meta-analysis included 23 eligible studies (21 articles) overall. We noticed that FokI SNP had a significant protective association with susceptibility to RA in the overall analysis as well as in Europeans and Asians. TaqI SNP decreased the RA risk in Africans and Arabs, but not in the overall analysis. Likewise, BsmI SNP and RA risk in the overall population analysis was not significant. Interestingly, BsmI polymorphism increased RA risk in Africans. This meta-analysis offers a significant association between VDR gene polymorphism and susceptibility to RA in both overall and ethnic-specific analysis. However, different polymorphisms acted inversely in increasing or decreasing RA risk in different populations.

Microbial and Host Factors That Affect Bacterial Invasion of the Gingiva

Periodontitis is a chronic inflammation of the periodontium caused by the loss of homeostasis between subgingival biofilms and susceptible hosts. Bacterial invasion into the gingival tissue and persistent infection are major events that lead to chronic inflammation. The intratissue bacterial communities are as complex as the subgingival biofilms and can also form biofilm-like structures, which will serve as a reservoir for local and systemic infections. The epithelium forms physical, chemical, and immunological barriers against invading microbes. Nevertheless, many bacterial species can invade the gingival epithelium through transcellular and paracellular pathways. In addition, both genetic and environmental factors of the hosts can affect epithelial barrier functions and thus bacterial invasion of the gingiva. In this review, current evidence for the bacterial invasion of the gingival tissue in periodontitis has been summarized, and the microbial and host factors that determine bacterial invasion of the gingiva have been reviewed.

The impact of maternal and early life malnutrition on health: a diet-microbe perspective

BACKGROUND

Early-life malnutrition may have long-lasting effects on microbe-host interactions that affect health and disease susceptibility later in life. Diet quality and quantity in conjunction with toxin and pathogen exposure are key contributors to microbe-host physiology and malnutrition. Consequently, it is important to consider both diet- and microbe-induced pathologies as well as their interactions underlying malnutrition.

MAIN BODY

Gastrointestinal immunity and digestive function are vital to maintain a symbiotic relationship between the host and microbiota. Childhood malnutrition can be impacted by numerous factors including gestational malnutrition, early life antibiotic use, psychological stress, food allergy, hygiene, and exposure to other chemicals and pollutants. These factors can contribute to reoccurring environmental enteropathy, a condition characterized by the expansion of commensal pathobionts and environmental pathogens. Reoccurring intestinal dysfunction, particularly during the critical window of development, may be a consequence of diet-microbe interactions and may lead to life-long immune and metabolic programming and increased disease risk. We provide an overview of the some key factors implicated in the progression of malnutrition (protein, fat, carbohydrate, iron, vitamin D, and vitamin B12) and discuss the microbiota during early life that may contribute health risk later in life.

CONCLUSION

Identifying key microbe-host interactions, particularly those associated with diet and malnutrition requires well-controlled dietary studies. Furthering our understanding of diet-microbe-host interactions will help to provide better strategies during gestation and early life to promote health later in life.

Serum 25-hydroxyvitamin D level and vitamin D receptor (VDR) polymorphisms in patients infected with Leishmania tropica: a case control study

Leishmania, an obligate intracellular parasite is eliminated by a strong Th-1 host response. As Vitamin D metabolism and its receptor activity are important factors in human native immune system against some microorganisms, we hypothesized that VDR gene polymorphisms and concentration of Vitamin D might have effect on incidence of cutaneous leishmaniasis. The aim of this study was to investigate the association between VDR gene polymorphism and/or the serum vitamin D level and leishmaniasis in the infected patients in comparison to the healthy individuals. In this case-control study, the BsmI, FokI and Taq1 polymorphisms in the VDR gene and serum levels of vitamin D were studied in Iranian infected with Leishmania tropica (n = 50) and healthy controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and Electrochemiluminescence methods respectively. Data were statistically analyzed using SPSS software, Chi square and ANOVA tests. The results of this study showed that despite the relatively higher frequency of BsmI-BB, FokI-FF and TaqI-Tt than Non BsmI-BB, Non FokI-FF and Non TaqI-Tt in the patients compared with the healthy individuals, the differences were not statistically significant (P > 0.05). Based on our findings, the relationship between the VDR polymorphism, the serum concentration of 25-hydroxyvitamin D and the susceptibility to Leishmania tropica infection, remains unclear requiring further in-depth studies. However, for better interpretation, it is necessary to consider factors such as the size of the sample examined and the other alleles of VDR, including ApaI.

Evidence Supporting a Phased Immuno-physiological Approach to COVID-19 From Prevention Through Recovery

This paper presents an evidence-based strategy for improving clinical outcomes in COVID-19. Recommendations are based on the phases of the disease, because optimal interventions for one phase may not be appropriate for a different phase. The four phases addressed are: Prevention, Infection, Inflammation and Recovery. Underlying this phased approach is recognition of emerging evidence for two different components of pathophysiology, early infection and late stage severe complications. These two aspects of the disease suggest two different patterns of clinical emphasis that seem on the surface to be not entirely concordant. We describe the application of therapeutic strategies and appropriate tactics that address four main stages of disease progression for COVID-19. Emerging evidence in COVID-19 suggests that the SARS-CoV-2 virus may both evade the innate immune response and kill macrophages. Delayed innate immune response and a depleted population of macrophages can theoretically result in a blunted antigen presentation, delaying and diminishing activation of the adaptive immune response. Thus, one clinical strategy involves supporting patient innate and adaptive immune responses early in the time course of illness, with the goal of improving the timeliness, readiness, and robustness of both the innate and adaptive immune responses. At the other end of the disease pathology spectrum, risk of fatality in COVID-19 is driven by excessive and persistent upregulation of inflammatory mechanisms associated with cytokine storm. Thus, the second clinical strategy is to prevent or mitigate excessive inflammatory response to prevent the cytokine storm associated with high mortality risk. Clinical support for immune system pathogen clearance mechanisms involves obligate activation of immune response components that are inherently inflammatory. This puts the goals of the first clinical strategy (immune activation) potentially at odds with the goals of the second strategy(mitigation of proinflammatory effects). This creates a need for discernment about the time course of the illness and with that, understanding of which components of an overall strategy to apply at each phase of the time course of the illness. We review evidence from early observational studies and the existing literature on both outcomes and mechanisms of disease, to inform a phased approach to support the patient at risk for infection, with infection, with escalating inflammation during infection, and at risk of negative sequelae as they move into recovery.

Vitamin D and microbiota: Two sides of the same coin in the immunomodulatory aspects

The gut microbiota is crucial for host immune response, vitamin synthesis, short chain fatty acids (SCFAs) production, intestinal permeability, nutrient digestion energy metabolism and protection from pathogens. Therefore, gut microbiota guarantees the host's predisposition to gastrointestinal diseases. Intestinal microbiota may be damaged by environmental components with negative health conditions. Dysbiosis consisting in alteration in the gut microbiota has been involved in several disorders including inflammation, allergic reactions, autoimmune diseases, heart diseases, obesity, and metabolic syndrome and even in the state of malignant carcinogenesis existing in humans. Several epidemiological studies have shown that inadequate solar exposure results in vitamin D insufficiency/deficiency which has a strong impact on different immune responses and the occurrence of a wide range of pathological conditions. Additionally, new evidence indicates that the vitamin D pathway plays a key role in gut homeostasis. Due to the strong connection between vitamin D and microbiota, herein we focus on the new findings about intestinal bacteria-immune crosstalk and the impact of vitamin D in gut microbiota regulation, in order to offer new clarifications on their interaction. Understanding the mechanism by which vitamin D can affect the gut microbiota composition and its dynamic activities, as well as the innate and adaptive state of the immune system, is not only a fundamental research but also an opportunity to improve health status.

Disputable Issues of Etiology and Pathogenesis of Tertiary Hyperparathyroidism

Hyperparathyroidism is a clinical and laboratory syndrome characterized by high production of the chief cells of the parathyroid hormone, a calcium-phosphorus metabolism disorder and the organ failure (kidneys, bone tissue).There are primary, secondary and tertiary hyperparathyroidism.This literature review is focused on tertiary hyperparathyroidism and includes the following sections: definition of different forms of hyperparathyroidism, the role of vitamin D in the tertiary hyperparathyroidism development, the development of tertiary hyperparathyroidism in chronic kidney disease patients, the development of tertiary hyperparathyroidism in patients after kidney transplantation, differential diagnosis various forms of hyperparathyroidism, indications for surgical tertiary hyperparathyroidism treatment in patients with kidney disease, in patients with normal kidney function.Objective. The objective of this literature review is to study the current information about this definition, pathogenesis, diagnosis and treatment of tertiary hyperparathyroidism.Methodology. The literature review was taken in English data bases MEDLINE (Pubmed), Scopus, Cochlear library, using following keywords: “secondary hyperparathyroidism pathogenesis diagnosis treatment”, “tertiary hyperparathyroidism pathogenesis diagnosis treatment”, “development of tertiary hyperparathyroidism from secondary hyperparathyroidism”, “chronic vitamin D deficiency, hyperparathyroidism”, “early stages of chronic renal failure, hyperparathyroidism”. Also, search for the same keywords was completed in Russian data base Elibrary.Discussion. Both the lack of a common understanding of this problem, and the presence of diverse and contradictory data of the etiology and pathogenesis indicate the need for further study of tertiary hyperparathyroidism.

Imbalance of autophagy and apoptosis in intestinal epithelium lacking the vitamin D receptor

Apoptosis and autophagy are dynamic processes that determine the fate of cells. Vitamin D receptor (VDR) deficiency in the intestine leads to abnormal Paneth cells and impaired autophagy function. Here, we will elucidate the mechanisms of the intestinal epithelial VDR regulation of autophagy and apoptosis. We used in vivo VDR^lox and VDR^∆IEC mice and ex vivo organoids generated from small intestine and colon tissues. We found that VDR deficiency induced more apoptotic cells and significantly increased cell death in the small intestine and colon of VDR^∆IEC mice. The proapoptotic protein B-cell lymphoma 2 (BCL-2) associated X protein (Bax) was enhanced, whereas autophagy related 16 like 1 (ATG16L1) and Beclin-1 were decreased in the intestines of VDR^ΔIEC mice. Apoptosis induced by Bax reduced autophagy by decreasing Beclin-1. Physical interactions between Beclin-1 and Bcl-2 were increased in the VDR-deficient epithelia from mice. The growth of VDR^∆IEC organoids was significantly slower with fewer Paneth cells than that of VDR^+/+ organoids. The expression levels of Beclin-1 and lysozyme were decreased in VDR^∆IEC organoids. Bacterial endotoxin levels were high in the serum from VDR^∆IEC mice and made mice susceptible to colitis. In the organoids and colitis IL-10^-/- mice, vitamin D₃ treatment increased VDR and ATG16L1 protein expression levels, which activated autophagic responses. In summary, intestinal epithelial VDR regulates autophagy and apoptosis through ATG16L1 and Beclin-1. Our studies provide fundamental insights into the tissue-specific function of VDR in modulating the balance between autophagy and apoptosis.-Lu, R., Zhang, Y.-G., Xia, Y., Sun, J. Imbalance of autophagy and apoptosis in intestinal epithelium lacking the vitamin D receptor.

Nuclear Receptors Regulate Intestinal Inflammation in the Context of IBD

Gastrointestinal (GI) homeostasis is strongly dependent on nuclear receptor (NR) functions. They play a variety of roles ranging from nutrient uptake, sensing of microbial metabolites, regulation of epithelial intestinal cell integrity to shaping of the intestinal immune cell repertoire. Several NRs are associated with GI pathologies; therefore, systematic analysis of NR biology, the underlying molecular mechanisms, and regulation of target genes can be expected to help greatly in uncovering the course of GI diseases. Recently, an increasing number of NRs has been validated as potential drug targets for therapeutic intervention in patients with inflammatory bowel disease (IBD). Besides the classical glucocorticoids, especially PPARγ, VDR, or PXR-selective ligands are currently being tested with promising results in clinical IBD trials. Also, several pre-clinical animal studies are being performed with NRs. This review focuses on the complex biology of NRs and their context-dependent anti- or pro-inflammatory activities in the regulation of gastrointestinal barrier with special attention to NRs already pharmacologically targeted in clinic and pre-clinical IBD treatment regimens.

Impact of Toll-Like Receptor 4 Signaling in Necrotizing Enterocolitis: The State of the Science

Necrotizing enterocolitis (NEC) remains a leading cause of preterm infant mortality. NEC is multifactorial and believed a consequence of intestinal immaturity, microbial dysbiosis, and an exuberant inflammatory response. Over the past decade, exaggerated Toll-like receptor 4 (TLR4) activity in the immature intestine of preterm neonates emerged as an inciting event preceding NEC. Increased TLR4 signaling in epithelial cells results in the initiation of an uncontrolled immune response and destruction of the mucosal barrier. This article discusses the state of the science of the molecular mechanisms involved in TLR4-mediated inflammation during NEC and the development of new therapeutic strategies to prevent NEC.

Activation of vitamin D in the gingival epithelium and its role in gingival inflammation and alveolar bone loss

BACKGROUND AND OBJECTIVE

Both chronic and aggressive periodontal disease are associated with vitamin D deficiency. The active form of vitamin D, 1,25(OH)₂ D₃ , induces the expression of the antimicrobial peptide LL-37 and innate immune mediators in cultured human gingival epithelial cells (GECs). The aim of this study was to further delineate the mechanism by which vitamin D enhances the innate defense against the development of periodontal disease (PD).

MATERIALS AND METHODS

Wild-type C57Bl/6 mice were made deficient in vitamin D by dietary restriction. Cultured primary and immortalized GEC were stimulated with 1,25(OH)₂ D₃ , followed by infection with Porphyromonas gingivalis, and viable intracellular bacteria were quantified. Conversion of vitamin D₃ to 25(OH)D₃ and 1,25(OH)₂ D₃ was quantified by ELISA. Effect of vitamin D on basal IL-1α expression in mice was determined by topical administration to the gingiva of wild-type mice, followed by qRT-PCR.

RESULTS

Dietary restriction of vitamin D led to alveolar bone loss and increased inflammation in the gingiva in the mouse model. In primary human GEC and established human cell lines, treatment of GEC with 1,25(OH)₂ D₃ inhibited the intracellular growth of P. gingivalis. Cultured GEC expressed two 25-hydroxylases (CYP27A1 and CYP2R1), as well as 1-α hydroxylase, enabling conversion of vitamin D to both 25(OH)D₃ and 1,25(OH)₂ D₃ . Topical application of both vitamin D₃ and 1,25(OH)₂ D₃ to the gingiva of mice led to rapid inhibition of IL-1α expression, a prominent pro-inflammatory cytokine associated with inflammation, which also exhibited more than a 2-fold decrease from basal levels in OKF6/TERT1 cells upon 1,25(OH)₂ D₃ treatment, as determined by RNA-seq.

CONCLUSION

Vitamin D deficiency in mice contributes to PD, recapitulating the association seen in humans, and provides a unique model to study the development of PD. Vitamin D increases the activity of GEC against the invasion of periodontal pathogens and inhibits the inflammatory response, both in vitro and in vivo. GEC can convert inactive vitamin D to the active form in situ, supporting the hypothesis that vitamin D can be applied directly to the gingiva to prevent or treat periodontal disease.

Serum concentrations of lipid-soluble vitamins in dogs with exocrine pancreatic insufficiency treated with pancreatic enzymes

Background

In humans, exocrine pancreatic insufficiency (EPI) is associated with deficiencies in lipid‐soluble vitamins. Little is reported regarding lipid‐soluble vitamin status in dogs with EPI.

Hypothesis/Objectives

Compare serum concentrations of retinol, 25‐hydrocholecalciferol (25OHD), and α‐tocopherol among dogs with EPI, those with subclinical EPI (sEPI), and healthy dogs. Detect associations between serum concentrations of lipid‐soluble vitamins and residual clinical signs in treated dogs with EPI and sEPI.

Animals

Twenty dogs with EPI and five dogs with sEPI receiving pancreatic enzyme replacement therapy. Ten healthy dogs sampled before and after 10 days of pancreatic enzyme supplementation.

Methods

Case‐control study. Serum retinol and α‐tocopherol concentrations were measured by high‐performance liquid chromatography. Serum 25OHD concentrations were measured by radioimmunoassay.

Results

Serum retinol concentration was significantly lower in dogs with EPI (median, 490 ng/mL; range, 322‐990 ng/mL) and serum α‐tocopherol concentration was significantly lower in dogs with EPI (median, 11.51 μg/L; range, 4.8‐27.1 μg/L) and sEPI (median, 12.66 μg/L; range, 10.21‐21.03 μg/L) compared with healthy dogs (median, 1203 ng/mL; range, 637‐1768 ng/mL and median, 43.54 μg/L; range, 34.26‐53.97 μg/L, respectively). Dogs with weight loss had significantly lower 25OHD (mean, 243.50 nmol/L; standard deviation [SD], 3.54 nmol/L) than dogs with stable weight (314.0 nmol/L; SD, 138.38 nmol/L).

Conclusions and Clinical Importance

Altered homeostasis of lipid‐soluble vitamins is present in dogs with EPI and sEPI, despite enzyme replacement therapy. Additional studies are needed to determine the clinical relevance of these findings and the therapeutic potential of lipid‐soluble vitamin supplementation in dogs with EPI and sEPI.

Vitamin D receptor gene polymorphism, serum 25-hydroxyvitamin D levels, and risk of vitiligo: A meta-analysis

OBJECTIVES

To explore the relationship among the vitamin D receptor (VDR) gene polymorphisms, serum 25-hydroxyvitamin D levels, and vitiligo.

METHODS

Databases including PubMed, Cochrane Library, Ovid, Web of Science, CNKI, SinoMed, and Wanfang Data were systematically searched. The association was assessed using odds ratios (ORs), standard mean difference (SMD), and 95% confidence intervals (CIs). The statistical tests were performed using Review Manager 5.3.3.

RESULTS

We identified a total of 17 studies. The relationship between VDR gene polymorphisms (BsmI, ApaI, TaqI, and FokI), serum 25 (OH)D levels, and incidence of vitiligo was investigated. The results of this meta-analysis showed that the dominant genetic model (CC+AC vs AA, P = .007, OR = 1.41, 95% CI = 1.10-1.80), recessive genetic model (CC vs AC+AA, P = .01, OR = 4.10, 95% CI = 1.36-12.35), and allelic contrast model (C vs A, P = .005, OR = 1.87, 95% CI = 1.21-2.90) of VDR Apal locus increased the risk of vitiligo, and BsmI, TaqI, and FokI loci and the risk of vitiligo have no obvious correlation. Serum 25 (OH)D deficiency was positively associated with the incidence of vitiligo (P < .0001, SMD = -0.94, 95% CI = -1.39, -0.48).

CONCLUSION

This meta-analysis revealed that VDR Apal polymorphism increased the susceptibility risk of vitiligo, and there is a positive correlation between serum 25 (OH)D deficiency and the incidence of vitiligo.

A decrease in vitamin D levels is associated with methotrexate-induced oral mucositis in children with acute lymphoblastic leukemia

Purpose

Children with acute lymphoblastic leukemia (ALL) are at increased risk of vitamin D deficiency, which might make them more susceptible to developing adverse events. Previous studies showed that low vitamin D levels were associated with an increased inflammatory mucosal state and impaired mucosal tissue barriers. We examined the prevalence of vitamin D deficiency and studied the association between vitamin D levels and methotrexate (MTX)-induced oral mucositis in pediatric ALL.

Methods

We assessed 25-hydroxyvitamin D (25(OH)D₃) and 24,25-dihydroxyvitamin D (24,25(OH)₂D₃) levels in 99 children with ALL before the start of 4 × 5 g/m² high-dose methotrexate (HD-MTX) (T0) and in 81/99 children after discontinuation of HD-MTX (T1). Two cutoff values for vitamin D deficiency exist: 25(OH)D₃ levels < 30 and < 50 nmol/L. Oral mucositis was defined as grade ≥ 3 according to the National Cancer Institute Criteria.

Results

Vitamin D deficiency occurred in respectively 8% (< 30 nmol/L) and 33% (< 50 nmol/L) of the patients at T0, and more frequently in children > 4 years of age as compared to children between 1 and 4 years of age. A decrease in 25(OH)D₃ levels during HD-MTX therapy was associated with developing severe oral mucositis (OR 1.6; 95% CI [1.1–2.4]). 25(OH)D₃ and 24,25(OH)₂D₃ levels at T0 and the change in 24,25(OH)₂D₃ levels during therapy were not associated with the development of severe oral mucositis.

Conclusions

This study showed that vitamin D deficiency occurs frequently in pediatric ALL patients above the age of 4 years. A decrease in 25(OH)D₃ levels during MTX therapy was observed in children with ALL that developed severe oral mucositis.

Electronic supplementary material

The online version of this article (10.1007/s00520-018-4312-0) contains supplementary material, which is available to authorized users.