High Dose Intramuscular Vitamin D3 Supplementation Impacts the Gut Microbiota of Patients With Clostridioides Difficile Infection.

Background and Aim: Current therapeutic strategies for Clostridioides difficile infections (CDI), including oral vancomycin, metronidazole and fecal microbial transplantation, have limited efficacy and treatment failure may occur in as many as one- third of cases. Recent studies have reported that lower concentrations of 25-hydroxyvitamin D are associated with CDI severity and recurrence. However, there have been no studies on microbiota composition after the administration of vitamin D in patients with CDI. Therefore, our study aimed to compare the microbiota composition between the two groups, including eight CDI-positive patients with vitamin D supplementation and ten CDI-positive patients without vitamin D supplementation by using 16S rRNA microbial profiling. Methods: Twenty subjects were enrolled in this prospective randomized controlled study. One subject dropped out due to lack of contact with the guardian after discharge and one subject dropped out due to withdrawal of consent. Thus, 18 patients with CDI and vitamin D insufficiency (vitamin D level < 17 ng/mL) were divided into two groups: CDI with vitamin D supplementation (n = 8) and CDI without vitamin D supplementation (control: n = 10). Subjects with vitamin D insufficiency were randomized to receive 200,000 IU intramuscular cholecalciferol whereas patients in the control group received only oral vancomycin. Stool samples were obtained twice before vancomycin was administered and eight weeks after treatment; the V3-V4 16S rRNA metagenomic sequencing was performed using EzBioCloud. Results: The alpha diversity of the gut microbiota in the recovery state was significantly higher than that in the CDI state. Analysis of bacterial relative abundance showed significantly lower Proteobacteria and higher Lachnospiraceae, Ruminococcaceae, Akkermansiaceae, and Bifidobacteriaceae in the recovery state. When comparing the control and vitamin D treatment groups after eight weeks, increase in alpha diversity and, abundance of Lachnospiraceae, and Ruminococcaceae exhibited the same trend in both groups. A significant increase in Bifidobacteriaceae and Christensenellaceae was observed in the vitamin D group; Proteobacteria abundance was significantly lower in the vitamin D treatment group after eight weeks than that in the control group. Conclusion: Our study confirmed that the increase in the abundance of beneficial bacteria such as Bifidobacteriaceae, and Christensenellaceae were prominently evident during recovery after administration of a high dose of cholecalciferol. These findings indicate that vitamin D administration may be useful in patients with CDI, and further studies with larger sample sizes are required.

Lower serum levels of vitamin D in adults with urinary tract infection.

PURPOSE: We aimed to explore the association between urinary tract infection (UTI) in adults and serum 25-hydroxyvitamin D (25OHD), which was used to access vitamin D status. METHODS: Serum levels of 25OHD were retrospectively analyzed in 234 subjects (190 females and 44 males): 120 UTI patients (females = 103) and 114 age- and sex-matched healthy controls (females = 87). Serum 25OHD concentrations were categorized as follows: (1) < 20 ng/mL, 20 to < 30 ng/mL, and ≥ 30 ng/mL; (2) < 20 ng/mL and ≥ 20 ng/mL. RESULTS: Serum 25OHD levels were lower in patients with UTI (p < 0.01). Women with UTI presented significantly lower 25OHD concentrations than those without UTI (p < 0.01). No association between serum 25OHD levels and UTI in men was found (p > 0.05). The multivariable logistic regression models showed significant associations between UTI and 25OHD, female sex, neutrophilic lymphocyte ratio and C-reactive protein (p < 0.05). CONCLUSION: Lower 25OHD concentrations associated with UTI were most prominent among women. The associations between UTI and low serum 25OHD levels as well as female sex were independent of each other.

Nutrition, Inflammation, and the Gut Microbiota among Outpatients with Active Tuberculosis Disease in India.

India has the highest rates of tuberculosis (TB) globally and a high prevalence of malnutrition; however, the interplay between host nutritional status, inflammation, and the gut microbiome in active tuberculosis disease (ATBD) is less well-studied. We examined differences in gut microbial composition and diversity based on undernutrition and inflammation status among outpatients with ATBD at the time of treatment initiation. During this exploratory cross-sectional study, outpatients (N = 32) with ATBD (confirmed by Xpert MTB/RIF) were enrolled in anti-TB treatment initiated at a hospital in rural southern India. The 16S rRNA sequencing was used to assess the composition of the gut microbiome. We assessed multiple markers of nutritional status, including micronutrient status concentrations (vitamin D [25(OH)D], vitamin B12, ferritin), anthropometry (body mass index, mid-upper arm circumference, and height), and C-reactive protein (CRP), as indicators of inflammation. We found that 25(OH)D was positively associated with the relative abundance of Oscillospira spp., a butyrate-producing genus linked with anti-inflammation effects, and that ferritin was positively associated with Proteobacteria taxa, which have been associated with worse inflammation in other studies. Finally, we found a greater abundance of inflammation-associated taxa from the Proteobacteria phylum and lower alpha-diversity indices among those who were underweight or who had low mid-upper arm circumference or short stature. In summary, we found differences in the gut microbiota composition and diversity among those with undernutrition compared with those with adequate nutrition status at the time of initiation of treatment among patients with ATBD in India. Clinical implications of these findings will need to be examined by larger longitudinal studies.

Cord Serum Calcitriol Inversely Correlates with Maternal Blood Pressure in Urinary Tract Infection-Affected Pregnancies: Sex-Dependent Immune Implications.

Urinary tract infections (UTI) during pregnancy are frequently associated with hypertensive disorders, increasing the risk of perinatal morbidity. Calcitriol, vitamin D3's most active metabolite, has been involved in blood pressure regulation and prevention of UTIs, partially through modulating vasoactive peptides and antimicrobial peptides, like cathelicidin. However, nothing is known regarding the interplay between placental calcitriol, cathelicidin, and maternal blood pressure in UTI-complicated pregnancies. Here, we analyzed the correlation between these parameters in pregnant women with UTI and with normal pregnancy (NP). Umbilical venous serum calcitriol and its precursor calcidiol were significantly elevated in UTI. Regardless of newborn's sex, we found strong negative correlations between calcitriol and maternal systolic and diastolic blood pressure in the UTI cohort (p < 0.002). In NP, this relationship was observed only in female-carrying mothers. UTI-female placentas showed higher expression of cathelicidin and CYP27B1, the calcitriol activating-enzyme, compared to male and NP samples. Accordingly, cord-serum calcitriol from UTI-female neonates negatively correlated with maternal bacteriuria. Cathelicidin gene expression positively correlated with gestational age in UTI and with newborn anthropometric parameters. Our results suggest that vitamin D deficiency might predispose to maternal cardiovascular risk and perinatal infections especially in male-carrying pregnancies, probably due to lower placental CYP27B1 and cathelicidin expression.

Pilot Trial of Vitamin D3 and Calcifediol in Healthy Vitamin D Deficient Adults: Does It Change the Fecal Microbiome?

CONTEXT: Experimental studies suggest that vitamin D receptor signaling may benefit the gut microbiome. In humans, whether vitamin D supplementation directly alters the gut microbiome is not well studied. OBJECTIVE: To determine whether correcting vitamin D deficiency with cholecalciferol (vitamin D3, D3) or calcifediol (25-hydroxyvitamin D3, 25(OH)D3) changes gut microbiome composition. METHODS: 18 adults with vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] <20 ng/mL) received 60 µg/day of D3 or 20 µg/day of 25(OH)D3 for 8 weeks. Changes in serum 25(OH)D, 1,25-diydroxyvitamin D (1,25(OH)2D), and 24,25-dihydroxyvitamin D (24,25(OH)2D) were assessed. We characterized composition of the fecal microbiota using 16S rRNA gene sequencing, and examined changes in α-diversity (Chao 1, Faith's Phylogenetic Diversity, Shannon Index), ß-diversity (DEICODE), and genus-level abundances (DESeq2). RESULTS: Vitamin D3 and 25(OH)D3 groups were similar. After 8 weeks of vitamin D3, mean 25(OH)D and 24,25(OH)2D increased significantly, but 1,25(OH)2D did not (25(OH)D: 17.8-30.1 ng/mL, P = .002; 24,25(OH)2D: 1.1 to 2.7 ng/mL, P =0.003; 1,25(OH)2D: 49.5-53.0 pg/mL, P = .9). After 8 weeks of 25(OH)D3, mean 25(OH)D, 24,25(OH)2D, and 1,25(OH)2D increased significantly (25(OH)D: 16.7-50.6 ng/mL, P < .0001; 24,25(OH)2D: 1.3-6.2 ng/mL, P = .0001; 1,25(OH)2D: 56.5-74.2 pg/mL, P = .05). Fecal microbial α-diversity and ß-diversity did not change with D3 or 25D3 supplementation. Mean relative abundance of Firmicutes increased and mean relative abundance of Bacterioidetes decreased from baseline to 4 weeks, but returned to baseline by study completion. DESeq2 analysis did not confirm any statistically significant taxonomic changes. CONCLUSION: In a small sample of healthy adults with vitamin D deficiency, restoration of vitamin D sufficiency with vitamin D3 or 25(OH)D3 did not lead to lasting changes in the fecal microbiota.

Association of Gut Microbiome and Vitamin D Deficiency in Knee Osteoarthritis Patients: A Pilot Study.

BACKGROUND: Few preclinical studies have shown that Knee osteoarthritis (KOA) is linked to gut microbiome dysbiosis and chronic inflammation. This pilot study was designed to look at the gut microbiome composition in KOA patients and normal individuals with or without vitamin D deficiency (VDD, serum vitamin D <30 ng/mL). METHODS: This pilot study was conducted prospectively in 24 participants. The faecal samples of all the participants were taken for DNA extraction. The V3-V4 region of 16s rRNA was amplified, and the library was prepared and sequenced on the Illumina Miseq platform. RESULTS: The mean (±SD) age was 45.5 (±10.2) years with no defined comorbidities. Of 447 total Operational Taxonomic Units (OTUs), a differential abundance of 16 nominally significant OTUs between the groups was observed. Linear discriminate analysis (LEfSe) revealed a significant difference in bacteria among the study groups. Pseudobutyrivibrio and Odoribacter were specific for VDD, while Parabacteroides, Butyricimonas and Gordonibacter were abundant in the KOA_VDD group, and Peptococcus, Intestimonas, Delftia and Oribacterium were abundant in the KOA group. About 80% of bacterial species were common among different groups and hence labelled as core bacterial species. However, the core microbiome of KOA and VDD groups were not seen in the KOA_VDD group, suggesting that these bacterial groups were affected by the interaction of the KOA and VDD factors. CONCLUSION: Parabacteroides, Butyricimonas, Pseudobutyrivibrio, Odoribacter and Gordonibacter are the predominant bacteria in vitamin D deficient patients with or without KOA. Together these results indicate an association between the gut microbiome, vitamin D and knee osteoarthritis.

A double burden of tuberculosis and diabetes mellitus and the possible role of vitamin D deficiency.

Tuberculosis remains a major global health challenge, particularly in low-to-middle income countries such as China. At the same time, the country is facing a rapidly increasing diabetes incidence over the last 10 years. Diabetes aggravates the tuberculosis epidemic which poses a serious challenge in public health. In recent years, the high prevalence of vitamin D deficiency represents a global health problem, which is also associated with the risk of diabetes, and tuberculosis. Therefore, this review aims to provide an overall and updated understanding of the epidemiology of co-occurrence of tuberculosis and diabetes in China, and to elucidate the possible role of vitamin D deficiency. In conclusion, significant aggravation of the tuberculosis epidemic due to diabetes may exist in China for a relatively long period of time to come. Further, the double burden and its implications to public health in this country may be significantly influenced by the high prevalence of vitamin D deficiency. Bidirectional screening for tuberculosis and diabetes is recommended, and extra vitamin D may benefit especially in a situation of a heavy tuberculosis burden combined with prevalent vitamin D deficiency. Longitudinal studies to verify the role of vitamin D deficiency in the double burden, and trials on the effect of vitamin D supplementation are needed in the future.

The Association between Vitamin D Deficiency and variants of Vitamin D Binding protein gene among Healthy Iranian Adults.

Background: The high prevalence of vitamin D deficiency may be due to both genetic and environment factors. The aim of this study was to demonstrate that vitamin D deficiency may be due to variants of vitamin D binding protein (DBP) among otherwise healthy Iranian adults. Methods: This cross-sectional study was conducted on 265 healthy adults in Tehran. Anthropometric and biochemical parameters were assessed. Dietary vitamin D intake was assessed with a Food Frequency Questionnaire (FFQ), and participant DBP genotypes were determined by polymerase chain reactions - restriction fragment length polymorphism. Results: Significant associations were found between vitamin D status and low-density lipoprotein cholesterol (P < 0.001), total cholesterol (P < 0.001), and fasting blood sugar (P < 0.001), after adjustment for confounder factors. This study demonstrated that "rs7041" gene was associated with vitamin D deficiency (OR = 0.63, ß ± SE = -0.46 ± 0.14, P < 0.0001). After considering the "GG" genotype of the "rs7041" polymorphism as a reference, the prevalence of vitamin D deficiency was found to be higher in the individuals with "TT" genotype from the "rs7041" polymorphism. Conclusion: It was found that the prevalence of vitamin D deficiency was higher in individuals with T allele carriers in the "rs7041" polymorphism.

Effect of Vitamin D Supplementation on Faecal Microbiota: A Randomised Clinical Trial.

In animal studies, vitamin D supplementation has been shown to improve gut microbiota and intestinal inflammation. However, limited evidence exists on the effect of vitamin D supplementation on the human gut microbiota. We examined the effect of vitamin D supplementation on faecal microbiota in 26 vitamin D-deficient (25-hydroxyvitamin D (25(OH)D) ≤50 nmol/L), overweight or obese (BMI ≥25 kg/m2) otherwise healthy adults. Our study was ancillary to a community based double-blind randomised clinical trial, conducted between 2014 and 2016. The participants provided stool samples at baseline and after 100,000 international units (IU) loading dose of cholecalciferol followed by 4000 IU daily or matching placebo for 16 weeks. Faecal microbiota was analysed using 16S rRNA sequencing; V6-8 region. There was no significant difference in microbiome α-diversity between vitamin D and placebo groups at baseline and follow-up (all p > 0.05). In addition, no clustering was found based on vitamin D supplementation at follow-up (p = 0.3). However, there was a significant association between community composition and vitamin D supplementation at the genus level (p = 0.04). The vitamin D group had a higher abundance of genus Lachnospira, and lower abundance of genus Blautia (linear discriminate analysis >3.0). Moreover, individuals with 25(OH)D >75 nmol/L had a higher abundance of genus Coprococcus and lower abundance of genus Ruminococcus compared to those with 25(OH)D <50 nmol/L. Our findings suggest that vitamin D supplementation has some distinct effects on faecal microbiota. Future studies need to explore whether these effects would translate into improved clinical outcomes.

Poor Vitamin D Status in Active Pulmonary Tuberculosis Patients and Its Correlation with Leptin and TNF-α.

Vitamin D deficiency (VDD) is common in tuberculosis (TB) and may be implicated in the etiology of the disease and in its clinical course. The aim of this study was to investigate the association between leptin, inflammatory markers and VD status in TB patients, stratified for presence or absence of diabetes mellitus (DM). Two hundred ninety-nine TB patients were recruited from October 2015 to August 2016. Also, 91 normal controls were included. The information including socio-demographics, dietary intake and living habits was obtained by face-to-face interview. Serum concentrations of leptin and TNF-α, CRP and IL-6 were compared between TB patients with and without severe VDD (SVDD). Pearson's correlation was used to analyze the association between TNF-α, leptin and 25-hydroxyvitamin D (25(OH)D). A significantly higher prevalence of VDD and SVDD was observed in TB patients compared with normal controls (93.0% vs 70.3%, 65.9% vs 3.3% respectively). Concentration of leptin was significantly lower, while TNF-α higher in TB patients with SVDD compared to those without (p<0.05). After adjustment for confounders, leptin was positively associated with 25(OH)D (r=0.210, p=0.002) with similar correlation in TB patients with DM (r=0.240, p=0.020). A negative association between TNF-α and 25(OH)D was observed (r=-0.197, p=0.003), which was significant only in the subgroup without DM (r=-0.304, p=0.001). Our findings indicate that a higher VD status in TB patients may be related to higher immune activity and less serious tissue damage, and that this relation is different according to presence or absence of DM co-morbidity.

Inflammatory bowel diseases: interrelationships between dietary vitamin D, exposure to UV radiation and the fecal microbiome.

Introduction: Environmental factors and an altered fecal microbiome are believed to be central to the pathogenesis of inflammatory bowel diseases (IBD). Vitamin D and ultraviolet radiation (UVR) are environmental factors that are associated by several pathways, including changes to the gastrointestinal microbiome, with the development and course of IBD.Area covered: This review explores the interaction of vitamin D, and UVR, with the intestinal innate and adaptive immune systems, and how they may influence the gut microbiome and the subsequent development, and progression, of IBD.Expert opinion: Vitamin D and UVR both regulate innate and adaptive immunity through a combination of common and independent mechanisms, with the overall effect being the promotion of immune tolerance. Vitamin D, and to a lesser extent UVR, can modify the gastrointestinal microbiome either directly, or through immune-mediated mechanisms and this may explain the effect on intestinal inflammation in animal models of IBD and some clinical studies. Thus, both vitamin D and UVR exposure can be considered potential 'master regulators' of gastrointestinal immunity, fine-tuning the complex interaction between genetics, host immunity and the gut microbiome. Further research and increased understanding of environment-host interactions is essential to achieving the ultimate goal of preventing and curing IBD.

Compounding effect of vitamin D3 diet, supplementation, and alcohol exposure on macrophage response to mycobacterium infection.

Vitamin D3 is known to be a key component in the defense against Mycobacterium tuberculosis (Mtb) infection through the regulation of cytokine and effector molecules. Conversely, alcohol exposure has been recognized as an immune dysregulator. Macrophages were extracted from D3 deficient and sufficient diet mice and supplemented with D3 or exposed to ethanol during ex vivo infection using M. bovis BCG, as a surrogate for Mtb. Results of our study indicate that while exogenous supplementation or alcohol exposure did alter immune response, in vivo diet was the greatest determinant of cytokine and effector molecule production. Alcohol exposure was found to profoundly dysregulate primary murine macrophages, with ethanol-exposed cells generally characterized as hyper- or hyporesponsive. Exogenous D3 supplementation had a normative effect for diet deficient host, however supplementation was not sufficient to compensate for the effects of diet deficiency. Vitamin D3 sufficient diet resulted in reduced cell cytotoxicity for the majority of time points. Results provide insight into the ramifications of both the individual and combined health risks of D3 deficiency or alcohol exposure. Given the clinical relevance of D3 deficiency and alcohol use comorbidities, outcomes of this study have implications in therapeutic approaches for the treatment of tuberculosis disease.

Irritable bowel syndrome: a review of the general aspects and the potential role of vitamin D.

INTRODUCTION: Irritable Bowel Syndrome (IBS) is a bowel disorder leading to symptoms such as abdominal pain, modifications in the motility and bowel habits, distention, bloating, and gas. Vitamin D (VD) may interfere in a plethora of cellular mechanisms, and act directly or indirectly in the regulation of the microbiome, the release of anti-microbial peptides, modulation of the immune system and inflammation processes; which in turn, may positively interfere with the altered gut function. The main purpose of this review was to survey studies involving the impacts of VD on IBS. Area covered: Eligible studies including the term VD and IBS were searched in the MEDLINE-PubMed and EMBASE (2009-2018). VD may act direct or indirectly in the regulation of the gut microbiome, immune response, and psychosocial factors that may be included in the list of IBS triggering factors. Expert opinion: Once VD plays an essential role in many processes associated with IBS, its deficiency may be associated with IBS, and the supplementation could help in the therapeutic approach for this condition. For these reasons, the understanding of the association of VD in IBS is indispensable for the development of new strategies that could improve the quality of life of the patient.

Vitamin D deficiency is associated with hepatic decompensation and inflammation in patients with liver cirrhosis: A prospective cohort study.

BACKGROUND: Vitamin D is required to maintain the integrity of the intestinal barrier and inhibits inflammatory signaling pathways. OBJECTIVE: Vitamin D deficiency might be involved in cirrhosis-associated systemic inflammation and risk of hepatic decompensation in patients with liver cirrhosis. METHODS: Outpatients of the Hepatology Unit of the University Hospital Frankfurt with advanced liver fibrosis and cirrhosis were prospectively enrolled. 25-hydroxyvitamin D (25(OH)D3) serum concentrations were quantified and associated with markers of systemic inflammation / intestinal bacterial translocation and hepatic decompensation. RESULTS: A total of 338 patients with advanced liver fibrosis or cirrhosis were included. Of those, 51 patients (15%) were hospitalized due to hepatic decompensation during follow-up. Overall, 72 patients (21%) had severe vitamin D deficiency. However, patients receiving vitamin D supplements had significantly higher 25(OH)D3 serum levels compared to patients without supplements (37 ng/mL vs. 16 ng/ml, P<0.0001). Uni- and multivariate analyses revealed an independent association of severe vitamin D deficiency with the risk of hepatic decompensation during follow-up (multivariate P = 0.012; OR = 3.25, 95% CI = 1.30-8.2), together with MELD score, low hemoglobin concentration, low coffee consumption, and presence of diabetes. Of note, serum levels of C-reactive protein, IL-6 and soluble CD14 were significantly higher in patients with versus without severe vitamin D deficiency, and serum levels of soluble CD14 levels declined in patients with de novo supplementation of vitamin D (median 2.15 vs. 1.87 ng/mL, P = 0.002). CONCLUSIONS: In this prospective cohort study, baseline vitamin D levels were inversely associated with liver-cirrhosis related systemic inflammation and the risk of hepatic decompensation.

The association between vitamin D status and tuberculosis in children: A meta-analysis.

BACKGROUND: Vitamin D deficiency (VDD) has been implicated in the pathogenesis of tuberculosis (TB), but most studies have not reported a significant association. We conducted a meta-analysis to explore the association between vitamin D status and TB in children. METHODS: Web of Science, Ovid Medline, and EMBASE were searched for studies in English that discussed vitamin D status and TB in children before January 22, 2018. RESULTS: From the 585 initially identified studies, we selected those that addressed an association between vitamin D status and TB according to our preselected inclusion criteria. Our meta-analysis included 10 studies. According to the random effects model, TB was significantly associated with VDD (ORs, 1.70; 95% CI, 1.20-2.42; P < .05) in children. Vitamin D levels were significantly lower in TB patients than in controls, with a mean difference d = -5.49 nmol/L (95% CI, -10.42 to -0.55; P < .05), indicating that VDD was significantly associated with TB (OR, 1.78; 95% CI, 1.30-2.44; P < .05) in children. CONCLUSION: This study suggests that vitamin D levels are significantly lower in children with TB/latent TB infection than in controls. TB may contribute to VDD in children. Therefore, VDD may be associated with TB in children.

Serum vitamin D levels and risk of prevalent tuberculosis, incident tuberculosis and tuberculin skin test conversion among prisoners.

Poor vitamin D status has been associated with tuberculosis (TB); whether poor status is cause or consequence of disease is uncertain. We conducted a case-control study and two nested case-control studies to determine whether vitamin D levels were associated with active TB, tuberculin skin test (TST) conversion, and risk of progression to the active TB in prisoners in Brazil. In multivariable conditional logistic regression, subnormal vitamin D levels (OR, 3.77; 95% CI, 1.04-13.64) were more likely in prisoners with active TB. In contrast, vitamin D was not found to be a risk factor for either TST conversion (OR, 2.49; 95% CI, 0.64-9.66) or progression to active disease (OR, 0.59; 95% CI, 0.13-2.62). Black race (OR, 11.52; 95% CI, 2.01-63.36), less than 4 years of schooling (OR, 2.70; 95% CI, 0.90-8.16), cigarette smoking (OR, 0.23; 95% CI, 0.06-0.79) were identified as risk factors for TST conversion. Risk of progression to active TB was found to be associated with cigarette smoking (OR, 7.42; 95% CI, 1.23-44.70). Our findings in the prison population show that poor vitamin D status is more common in individuals with active TB, but is not a risk factor for acquisition of latent TB or progression to active TB.

Bolus Weekly Vitamin D3 Supplementation Impacts Gut and Airway Microbiota in Adults With Cystic Fibrosis: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial.

Context: Disruption of gut microbiota may exacerbate severity of cystic fibrosis (CF). Vitamin D deficiency is a common comorbidity in patients with CF that may influence composition of the gut microbiota. Objectives: Compare microbiota of vitamin D-sufficient and -insufficient CF patients and assess impact of a weekly high-dose vitamin D3 bolus regimen on gut and airway microbiome in adults with CF and vitamin D insufficiency (25-hydroxyvitamin D < 30 ng/mL). Design: Forty-one subjects with CF were classified into two groups: vitamin D insufficient (n = 23) and vitamin D sufficient (n = 18). Subjects with vitamin D insufficiency were randomized to receive 50,000 IU of oral vitamin D3 or placebo weekly for 12 weeks. Sputum and stool samples were obtained pre- and postintervention and 16S ribosomal RNA genes sequenced using Illumina MiSeq technology. Results: Gut microbiota differed significantly based on vitamin D status with Gammaproteobacteria, which contain numerous, potentially pathogenic species enriched in the vitamin D-insufficient group. Principal coordinates analysis showed differential gut microbiota composition within the vitamin D-insufficient patients following 12 weeks treatment with placebo or vitamin D3 (permutation multivariate analysis of variance = 0.024), with Lactococcus significantly enriched in subjects treated with vitamin D3, whereas Veillonella and Erysipelotrichaceae were significantly enriched in patients treated with placebo. Conclusion: This exploratory study suggests that vitamin D insufficiency is associated with alterations in microbiota composition that may promote inflammation and that supplementation with vitamin D has the potential to impact microbiota composition. Additional studies to determine the impact of vitamin D on microbiota benefit clinical outcomes in CF are warranted.

Single-Dose, Preoperative Vitamin-D Supplementation Decreases Infection in a Mouse Model of Periprosthetic Joint Infection.

BACKGROUND: Despite recent advances, infection remains the most common etiology of arthroplasty failure. Recent work suggests that 25-hydroxyvitamin D (25D) deficiency correlates with the frequency of periprosthetic joint infection (PJI). We endeavored to examine whether 25D3 deficiency leads to increased bacterial burden in vivo in an established mouse model of PJI and, if so, whether this effect can be reversed by preoperative 25D3 supplementation. METHODS: Mice (lys-EGFP) possessing fluorescent neutrophils were fed a vitamin D3-sufficient (n = 20) or deficient (n = 40) diet for 6 weeks. A group of 25D3-deficient mice (n = 20) were "rescued" with 1 intraperitoneal dose of 25D3 at 3 days before surgery. A stainless steel implant was inserted into the knee joint and the joint space was inoculated with bioluminescent Staphylococcus aureus (1 × 10 colony forming units [CFUs]). In vivo imaging was used to monitor bacterial burden and neutrophil infiltration. Blood was drawn to confirm 25D3 levels 3 days before surgery and on postoperative days (PODs) 0 and 14. Mice were killed at POD 21, and CFUs were quantified after culture. Myeloperoxidase (MPO) and ß-N-acetylglucosaminidase (NAG) were assayed to look at neutrophil infiltration and activated tissue macrophage recruitment, respectively. RESULTS: Serum values confirmed 25D3 deficiency and repletion of the 25D3-rescued group. Bacterial bioluminescence and neutrophil fluorescence were significantly greater (p < 0.05) in the 25D3-deficient group. CFU counts from the joint tissue and implant were also significantly greater in this group (p < 0.05). Rescue treatment significantly decreased bacterial burden and neutrophil infiltration (p < 0.05). Compared with the 25D3-sufficient and 25D3-rescued groups, MPO activity was higher (p < 0.02) and NAG activity was lower (p < 0.03) in the 25D3-deficient group. CONCLUSIONS: This study demonstrated in vivo in a mouse model of PJI that (1) 25D3 deficiency results in increased bacterial burden and neutrophil infiltration, and (2) this effect can be reversed with preoperative repletion of 25D3. CLINICAL RELEVANCE: Considering that >65% of patients undergoing arthroplasty have insufficient or low levels of total 25D and that 25D levels can be replenished with ease using a U.S. Food and Drug Administration (FDA)-approved, oral 25D3 product, 25D deficiency may be an important modifiable risk factor in humans undergoing joint replacement.

Microbiota-Dependent Induction of Colonic Cyp27b1 Is Associated With Colonic Inflammation: Implications of Locally Produced 1,25-Dihydroxyvitamin D3 in Inflammatory Regulation in the Colon.

Our recent studies demonstrated that intestinal epithelial vitamin D receptor (VDR) signaling plays a critical role in regulating colonic inflammation by protecting epithelial barrier integrity. Epithelial VDR is downregulated in colitis, but how mucosal inflammation affects local 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] production is unknown. Here we showed that cytochrome P450 27b1 (Cyp27b1), a cytochrome P450 enzyme necessary for 1,25(OH)2D3 biosynthesis, is highly induced in colonic mucosa in inflammatory response. Although VDR is reduced in colon biopsies from patients with ulcerative colitis, Cyp27b1 is markedly upregulated in these samples. Colon mucosal Cyp27b1 was also markedly induced in an experimental colitis mouse model, and this local Cyp27b1 induction and colonic inflammation required the presence of commensal bacteria. Vitamin D deficiency further exaggerated colonic Cyp27b1 induction and aggravated colonic inflammation in mice. In HCT116 cells, lipopolysaccharide or tumor necrosis factor-α treatment induced Cyp27b1 in time- and dose-dependent manners, and the induced Cyp27b1 was enzymatically active. The inflammation-induced upregulation of Cyp27b1 was mediated by nuclear factor κB. Collectively these data suggest that induction of colonic epithelial Cyp27b1, which is expected to increase local production of 1,25(OH)2D3, is a protective mechanism that partially compensates for the downregulation of epithelial VDR during colonic inflammation. Increased local 1,25(OH)2D3 maintains 1,25(OH)2D3-VDR signaling to protect the mucosal barrier and reduce colonic inflammation.

Low serum vitamin D levels in type 2 diabetes patients are associated with decreased mycobacterial activity.

BACKGROUND: Concurrent diabetes mellitus and tuberculosis represent a significant health problem worldwide. Patients with diabetes mellitus have a high risk of tuberculosis, which may be mediated by an abnormal innate immune response due to hyperglycaemia or low vitamin D levels. METHODS: In the present study, we evaluated inactive vitamin D serum levels and the monocyte response to infection with M. tuberculosis, including phagocytosis of M. tuberculosis, antimycobacterial activity, LL-37, human ß defensin-2 and IL-10 gene expression and nitric oxide production, between type 2 diabetes mellitus patients (n = 51) and healthy volunteers (n = 38). RESULTS: Twenty-seven type 2 diabetes mellitus patients had inadequate inactive vitamin D levels (<50 nM). The percentages of M. tuberculosis phagocytosis between monocytes were similar across groups according to microscopy. Intracellular mycobacterial growth was similar in infected monocytes from both groups. However, M. tuberculosis growth was significantly higher in monocytes obtained from type 2 diabetes mellitus patients and lower vitamin D levels after 1-h (D0) and 72-h (D3) post-infection (p ≤ 0.05). LL-37, human ß defensin-2 and IL-10 mRNA expression were similar between monocytes across groups; vitamin D serum levels and LL-37, human ß defensin-2 and IL-10 expression were not correlated. Nitric oxide production was significantly higher in healthy volunteers than in type 2 diabetes mellitus patients with low vitamin D serum levels at D3 post-infection (p ≤ 0.05). CONCLUSIONS: Our results show that monocytes from type 2 diabetes mellitus patients and low vitamin D serum levels show an impaired ability to control the intracellular growth of M. tuberculosis, which is not associated with significant decrease of LL-37 or human ß defensin-2 expression. Vitamin D could be the link between diabetes and tuberculosis susceptibility.