Anti-Inflammatory and Antimicrobial Actions of Vitamin D in Combating TB/HIV

The dawn of repurposing vitamins as potential novel antimicrobial agents: A call for global emergency response amidst AMR crisis

Amidst, the global pandemic of antimicrobial resistance (AMR), the rate at which AMR increases overwhelms the increased efforts to discover new effective antimicrobials. There is a persistent need for alternative treatment modalities so as to keep up with the pace. AMR is the leading cause of death in the world and its health and economic consequences suggest the urgent need for sustainable interventions. Vitamins have consistently proven to have antimicrobial activity as well as slowing down the AMR rate by influencing the AMR genes even towards extensive multidrug resistant strains. Evidences suggest that the use of some vitamins on their own or in combination with existing antimicrobial agents could be a breakthrough towards combating AMR. This will widen the antimicrobial agents' options in the treatment arena, preserve the antimicrobial agents susceptible to develop resistant so that they can be used in severe infections only, reduce the tension and burden of the AMR crisis significantly and give enough room for development of new antimicrobial agents. Moreover, almost all viral, fungal, parasitic and bacterial resistant strains of concern as listed by World Health Organization have been found to be sensitive to several vitamins either synergistically with other antimicrobials or independently. Considering their widened spectrum of immunomodulatory and antimicrobial effect, some vitamins can further be repositioned as prophylactic antimicrobial agents in clinical situations like in presurgeries prophylaxis so as to avoid unnecessary use of antimicrobials especially antibiotics. Various relevant AMR stakeholders should invest in clinical trials and systematic reviews with available data to enable quick repositioning of some potential vitamins as antimicrobial agents as an emergency rapid response towards AMR Crisis. This includes the preparation of guidelines containing specificity of which vitamin to be used for treatment of which type of infection.

Case-control study of vitamin D status and adult multidrug-resistant pulmonary TB

BACKGROUND: India has the highest prevalence of multidrug-resistant TB (MDR-TB) globally. Vitamin D deficiency is potentially an important risk factor for MDR-TB.METHODS: We conducted a case-control study of 90 newly diagnosed adult MDR-TB cases, 180 household controls and 82 non-household controls in Mumbai, India. Serum 25-hydroxyvitamin D (25(OH)D), anthropometry, clinical status and history, dietary data and sociodemographic data were collected from each participant. Interferon-gamma release assay (IGRA) was also performed in controls to assess latent TB. Multivariable regression was performed to estimate associations between 25(OH)D vs. case status and IGRA positivity.RESULTS: Mean participant age was 33.8 ± 12.0 years; 72.8% had 25(OH)D <20 ng/ml. Mean 25(OH)D was significantly (P < 0.05) lower in cases (12.5 ± 7.9) than both household (17.5 ± 11.2) and non-household controls (16.4 ± 9.1). In multivariable models, 25(OH)D concentration was inversely associated with MDR-TB case status among cases and household controls (OR 0.95 per 1 ng/ml, 95% CI 0.92-0.99; P = 0.015), and among cases and non-household controls (OR 0.94 per 1 ng/ml, 95% CI 0.89-1.00; P = 0.033); 53.6% of controls were IGRA-positive. 25(OH)D status was not associated with IGRA positivity.CONCLUSION: Vitamin D status was independently associated with MDR-TB case status. Research should evaluate the effectiveness of vitamin D supplementation in prevention and adjunctive treatment of MDR-TB.

The Potential Role of Vitamin D in the Development of Tuberculosis in Chinese Han Population: One Case-Control Study

Background and aims:

Spinal serum 25-hydroxyvitamin D [25[OH]D] status plays an important role in mediating innate immune responses by acting as a cofactor for induction of antimycobacterial activity and is thus involved in the development of Tuberculosis (TB). Results reported regarding the association of vitamin D with TB remained controversial. We aimed to identify any common association between 25[OH]D status and TB in the Chinese Han population.

Methods

280 subjects (70 TB patients and 210 matched controls) were recruited. TB cases were diagnosed based on the presence of acid-fast bacilli on smears from sputum and MTB isolation. Healthy controls were randomly selected from four local community-based populations. 25[OH]D was detected by electrochemiluminescence immunoassay (ECLIA) on Roche Elecsys before the initial treatment. Multivariable logistic regression analysis was used to examine the association of Vitamin D with TB.

Results

There was no significant difference in the serum vitamin D level between total cases and controls, but we found a strong tendency toward a higher serum vitamin D level in male population (P &lt; 0.05) with TB but not in females. High serum vitamin D increased the risk of TB in the Chinese Han population (OR = 1.035, 95%CI: 1.001–1.070, P &lt; 0.05). The serum vitamin D level was significantly decreased with age increasing in cases and controls (all P &lt; 0.001).

Conclusions

High serum vitamin D may be an independent risk factor for TB in the Chinese Han population.

Calcitriol decreases HIV-1 transfer in vitro from monocyte-derived dendritic cells to CD4 + T cells, and downregulates the expression of DC-SIGN and SIGLEC-1

Dendritic cells (DCs) promote HIV-1 transmission by acting as Trojan horses, capturing viral particles, facilitating the infection of CD4+ T-cells. Vitamin D (VitD) has shown to decrease T cell activation, reducing susceptibility to HIV-1 infection of CD4+ T-cells in vitro; however, if VitD decreases viral transfer from DCs to CD4+ T-cells is unknown. In this study, we co-cultured HIV-1-pulsed immature and LPS mature monocytes-derived DCs (iDCs and LmDCs, respectively), differentiated in presence or absence of calcitriol (VitD active form), with PHA-activated autologous CD4+ T-cells from 16 healthy donors. In co-cultures of iDCs and LmDCs treated with calcitriol, there was a significant decrease in frequency of infected CD4+ T-cells, evaluated by flow cytometry. However, p24 levels evaluated by ELISA were not significantly reduced in culture supernatants. Moreover, calcitriol-treated iDCs exhibited decreased expression of genes involved in HIV-1 transfer compared to the control. Both, calcitriol-treated iDCs and LmDCs exhibit a similar gene expression profile, probably related to a transcriptional balance achieved after long treatment with calcitriol. Since calcitriol-differentiated DCs express on their surface a lower amount of DC-SIGN and SIGLEC-1 molecules, widely associated with HIV-1 transfer, suggesting that this mechanism contributes to a lower transfer of viral particles by the DCs.

The Effect of Vitamin D Supplementation on the Severity of Symptoms and the Quality of Life in Irritable Bowel Syndrome Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Irritable bowel syndrome (IBS), a gastrointestinal disorder affecting 7-12% of the population, is characterized by abdominal pain, bloating, and alternating bowel patterns. Data on risk and protective influences have yielded conflicting evidence on the effects of alternative interventions, such as vitamin D. This review focuses on the effects of vitamin D on IBS. A systematic review and meta-analysis considered all articles published until 4 April 2022. The search for randomized controlled trials assessing vitamin D efficacy in IBS with outcomes, primary (Irritable Bowel Severity Scoring System (IBS-SSS)) and secondary (IBS quality of life (IBS-QoL) and serum level of calcifediol (25(OH)D)), was performed on six databases, Google Scholar, Web of Science, SCOPUS, EMBASE, PubMed (MEDLINE), and Cochrane Central Register of Controlled Trials. We included six trials with 616 patients. The pooled analysis found no difference between vitamin D and placebo in improving IBS-SSS (MD: -45.82 with 95% CI [-93.62, 1.98], p = 0.06). However, the pooled analysis favored vitamin D over placebo in improving the IBS-Qol (MD: 6.19 with 95% CI [0.35, 12.03], p = 0.04) and serum 25(OH)D (MD: 25.2 with 95% CI [18.41, 31.98], p = 0.00001). Therefore, further clinical trials are required to reach clinically applicable and generalizable findings.

A brief review of vitamin D as a potential target for the regulation of blood glucose and inflammation in diabetes-associated periodontitis

Diabetes is a metabolic disorder associated with various complications, including periodontitis. The risk of periodontitis is increased in patients with diabetes, while vitamin D deficiency is associated with both diabetes and periodontitis. Thus, there is a need to identify the molecular effects of vitamin D on the regulation of inflammation and glucose in diabetes-associated periodontitis. The Web of Science, Scopus, and PubMed databases were searched for studies of the molecular effects of vitamin D. Molecular effects were reportedly mediated by salivary secretions, interactions of advanced glycation end products (AGEs) with receptors of AGEs (RAGEs), cytokines, and oxidative stress pathways linking diabetes with periodontitis. Vitamin D supplementation attenuates inflammation in diabetes-associated periodontitis by reducing the levels of inflammatory cytokines and numbers of immune cells; it also has antibacterial effects. Vitamin D reduces cytokine levels through regulation of the extracellular signal-related kinase 1/2 and Toll-like receptor 1/2 pathways, along with the suppression of interleukin expression. Glucose homeostasis is altered in diabetes either because of reduced insulin production or decreased insulin sensitivity. These vitamin D-related alterations of glucoregulatory factors may contribute to hyperglycaemia; hyperglycaemia may also lead to alterations of glucoregulatory factors. This review discusses the pathways involved in glucose regulation and effects of vitamin D supplementation on glucose regulation. Further studies are needed to characterise the effects of vitamin D on diabetes-associated periodontitis.

A single-oral bolus of 100,000 IU of cholecalciferol at hospital admission did not improve outcomes in the COVID-19 disease: the COVID-VIT-D-a randomised multicentre international clinical trial

BACKGROUND

Vitamin D status has been implicated in COVID-19 disease. The objective of the COVID-VIT-D trial was to investigate if an oral bolus of cholecalciferol (100,000 IU) administered at hospital admission influences the outcomes of moderate-severe COVID-19 disease. In the same cohort, the association between baseline serum calcidiol levels with the same outcomes was also analysed.

METHODS

The COVID-VIT-D is a multicentre, international, randomised, open label, clinical trial conducted throughout 1 year. Patients older than 18 years with moderate-severe COVID-19 disease requiring hospitalisation were included. At admission, patients were randomised 1:1 to receive a single oral bolus of cholecalciferol (n=274) or nothing (n=269). Patients were followed from admission to discharge or death. Length of hospitalisation, admission to intensive care unit (ICU) and mortality were assessed.

RESULTS

In the randomised trial, comorbidities, biomarkers, symptoms and drugs used did not differ between groups. Median serum calcidiol in the cholecalciferol and control groups were 17.0 vs. 16.1 ng/mL at admission and 29.0 vs. 16.4 ng/mL at discharge, respectively. The median length of hospitalisation (10.0 [95%CI 9.0-10.5] vs. 9.5 [95%CI 9.0-10.5] days), admission to ICU (17.2% [95%CI 13.0-22.3] vs. 16.4% [95%CI 12.3-21.4]) and death rate (8.0% [95%CI 5.2-12.1] vs. 5.6% [95%CI 3.3-9.2]) did not differ between the cholecalciferol and control group. In the cohort analyses, the highest serum calcidiol category at admission (>25ng/mL) was associated with lower percentage of pulmonary involvement and better outcomes.

CONCLUSIONS

The randomised clinical trial showed the administration of an oral bolus of 100,000 IU of cholecalciferol at hospital admission did not improve the outcomes of the COVID-19 disease. A cohort analysis showed that serum calcidiol at hospital admission was associated with outcomes.

TRIAL REGISTRATION

COVID-VIT-D trial was authorised by the Spanish Agency for Medicines and Health products (AEMPS) and registered in European Union Drug Regulating Authorities Clinical Trials (EudraCT 2020-002274-28) and in ClinicalTrials.gov ( NCT04552951 ).

Reduced levels of serum 25(OH)D3 are associated with tuberculosis positive cattle under conditions of high natural exposure to Mycobacterium bovis

Serum vitamin D (25(OH)D₃) concentrations of < 30 ng/mL in cattle are insufficient to induce an adequate immune response against intracellular pathogens, which suggests that the efficacy of the immune response may be highly dependent on the bioavailability of 25(OH)D₃. This study shows an overview of both in vitro and in vivo 25(OH)D3-mediated immune modulation amongst dairy cattle naturally exposed to M. bovis. Tuberculin status was confirmed by interferon gamma release assay (IGRA), and natural exposure was demonstrated by polymerase chain reaction (PCR). Tuberculin (-) cattle have a higher serum concentration of 25(OH)D₃ (X¯= 87.12 ng/mL) when compared to tuberculin (+) cattle (X¯ = 45.86 ng/mL). Reduced serum 25(OH)D₃ levels are associated with the presence of bovine TB, and serum 25(OH)D₃ levels of > 80 ng/mL are necessary to counteract infection by M. bovis. Kill assays were performed to evaluate in vitro 25(OH)D₃ modulation of intracellular M. bovis growth in bovine macrophages, which showed that reduced serum 25(OH)D₃ levels are associated with diminished mycobactericidal capacity in this experimental model. On the other hand, increased 25(OH)D₃ in culture media enhances phagocytosis and nitric oxide production, which in turn improves capacity to combat M. bovis.

Vitamin D3 Supplementation Effects on Spermatogram and Oxidative Stress Biomarkers in Asthenozoospermia Infertile Men: a Randomized, Triple-Blind, Placebo-Controlled Clinical Trial

The objective is to evaluate the effects of vitamin D3 (VD3) on sperm parameters and seminal and serum oxidative stress (OS) biomarkers in asthenozoospermia infertile men. This randomized, triple-masking, placebo-controlled clinical trial conducted on 86 asthenozoospermia infertile men with serum 25 hydroxy vitamin D3 (25-OH-D3) < 30 ng/ml in the infertility clinic of Ahvaz Jahad Daneshgahi, Iran. Patients were randomly allocated to groups A and B, who received daily 4000 IU vitamin D3 (VD3) and matching placebo respectively for 3 months. Demographic data, dietary intake, physical activity, sun exposure, anthropometric indices, serum and seminal levels of MDA (Malondialdehyde), 8-hydroxy-2- Dioxy Guanosine (8-OHDG), total antioxidant capacity (TAC) and calcium, sperm DNA fragmentation index (DFI), serum 25-OH-D3, parathyroid hormone (PTH), phosphorus, and sperm parameters were assessed. VD3 supplementation had no significant effects on body weight, body mass index (BMI), waist circumference (WC), body fat (BF), 8-OHDG, DFI, semen volume, sperm count, and normal sperm morphology, but increased post-intervention mean and mean change of serum 25-OH-D3 (P < 0.001, P < 0.001), PTH (P < 0.001, P < 0.001) and phosphorus (P = 0.009, P = 0.049) and seminal calcium (P = 0.035, P = 0.038) and serum calcium (P = 0.008, P = 0.009), seminal TAC (P < 0.001, P < 0.001), and serum TAC (P = 0.007, P = 005), total sperm motility (P < 0.001, P < 0.001) and progressive sperm motility (P < 0.001, P < 0.001) and decreased seminal MDA (P = 0.017, P = 0.004) and serum MDA (P = 006, P = 0.005) significantly compared to the baseline and placebo group respectively. VD3 supplementation may modulate OS and affect sperm motility in men with asthenozoospermia and serum 25-OH-D3 < 30 ng/ml. Iran Clinical Trials Registry, ID: IRCT20151128025274N4, registered on 28 March 2018, URL of trial registry record: https://www.irct.ir/trial/29983.

Evaluation of the effect of vitamin D supplementation on spermatogram, seminal and serum levels of oxidative stress indices in asthenospermia infertile men: a study protocol for a triple-blind, randomized controlled trial

BACKGROUND

It is suggested that vitamin D may have a beneficial role in male reproduction. The male reproductive system is a target tissue for vitamin D. This study will aim to evaluate the effects of vitamin D supplementation on sperm parameters, seminal and serum levels of oxidative stress and serum endocrine factors in asthenospermia infertile men.

METHODS/DESIGN

This randomized, triple-blind, placebo-controlled clinical trial will be conducted on 86 infertile men with idiopathic asthenozoospermia (the mobility of sperm < 40% and rapid progressive sperm motility < 32%), with serum levels of vitamin D less than 30 ng / ml in the "Infertility Clinic of Ahvaz Jahad daneshgahi", Iran.

MAIN OUTCOMES MEASURE (S)

Demographic data, dietary intake, physical activity, sun exposure, anthropometric indices, serum and seminal levels of MDA (Malondialdehyde), 8-hydroxy-2- Dioxy Guanosine (8-OHDG), Total Antioxidant Capacity (TAC) and calcium, sperm DNA fragmentation index (DFI), serum 25-OHD, luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone (T), estradiol (E2), sex hormone-binding globulin (SHBG), free androgen index (FAI = T/SHBG. 100), T/LH and T/E2 ratios, prolactin (PRO), parathyroid hormone (PTH), osteocalcin (OCN), phosphorus and sperm parameters.

DISCUSSION

The deficiency of vitamin D as an antioxidant is common all over the world. Numerous observational studies have shown a positive association between vitamin D levels and semen quality. However, few clinical studies have been conducted in this area. So considering with the high prevalence of this antioxidant deficiency specifically in infertile men, it seems that the supplementation of vitamin D in infertile men with insufficient levels or deficiency may improve the status of oxidative stress and thereby may affect sperm parameters and endocrine factors involved in male fertility.

TRIAL REGISTRATION

Iran Clinical Trials Registry, ID: IRCT20151128025274N4 , registered on 28 March 2018.

Protocol for a case-control study of vitamin D status, adult multidrug-resistant tuberculosis disease and tuberculosis infection in Mumbai, India

INTRODUCTION

Vitamin D status may be an important determinant of multidrug-resistant tuberculosis (MDR-TB) infection, progression to disease and treatment outcomes. Novel and potentially cost-effective therapies such as vitamin D supplementation are needed to stem the tide of TB and MDR-TB globally, particularly in India, a country that accounts for the largest fraction of the world's TB incidence and MDR-TB incidence, and where vitamin D deficiency is endemic. While vitamin D has shown some promise in the treatment of MDR-TB, its role in the context of MDR-TB infection and progression to disease is largely unknown.

METHODS AND ANALYSIS

Through a case-control study in Mumbai, India, we aim to examine associations between vitamin D status and active MDR-TB and to investigate vitamin D status and TB infection among controls. Cases are adult outpatient pulmonary patients with MDR-TB recruited from two public TB clinics. Controls are recruited from the cases' household contacts and from non-respiratory departments of the facilities where cases were recruited. Cases and controls are assessed for serum 25-hydroxyvitamin D concentration, nutrient intake, diet quality, anthropometry and other relevant clinical and sociodemographic parameters. Controls undergo additional clinical assessments to rule out active TB and laboratory assessments to determine presence of TB infection. Statistical analysis investigates associations between vitamin D status and active MDR-TB and between vitamin D status and TB infection among controls, accounting for potential confounding effects of diet, anthropometry and other covariates.

ETHICS AND DISSEMINATION

This study has been approved by Harvard T.H. Chan School of Public Health Institutional Review Board; Foundation for Medical Research Institutional Research Ethics Committee and Health Ministry's Screening Committee of the Indian Council for Medical Research. Permission was granted by the Municipal Corporation of Greater Mumbai, India, a collaborating partner on this research. Outcomes will be disseminated through publication and scientific presentation.

TRIAL REGISTRATION NUMBER

NCT04342598.

Effectiveness of vitamin D supplementation on the outcome of pulmonary tuberculosis treatment in adults: a meta-analysis of randomized controlled trials

Supplemental Digital Content is available in the text

Background:

Tuberculosis (TB) is one of the most debilitating diseases worldwide. Current studies have shown that vitamin D plays a significant role in host immune defense against Mycobacterium tuberculosis, but clinical trials reported inconsistent results. Therefore, we systematically reviewed the literature to investigate whether vitamin D supplementation could improve the effect of anti-TB therapy.

Methods:

We systematically searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from their inception to February 8th, 2019 for randomized controlled trials on vitamin D supplementation in patients with pulmonary TB receiving anti-TB therapy. The primary outcomes were time to sputum culture and smear conversion and proportion of participants with negative sputum culture. The secondary outcomes were clinical response to treatment and adverse events. A random-effects model was used to pool studies. Data were analyzed using RevMan 5.3 software.

Results:

Five studies with a total of 1126 participants were included in our meta-analysis. Vitamin D supplementation did not shorten the time to sputum culture and smear conversion (hazard ratio [HR] 1.04, 95% confidence interval [CI] 0.89–1.23, P = 0.60; HR 1.15, 95% CI 0.93–1.41, P = 0.20, respectively) and did not lead to an increase in the proportion of participants with negative sputum culture (relative risk [RR] 1.04, 95% CI 0.97–1.11, P = 0.32). However, it reduced the time to sputum culture conversion in the sub-group of participants with TaqI tt genotype (HR 8.09, 95% CI 1.39–47.09, P = 0.02) and improved the multidrug-resistant (MDR) TB sputum culture conversion rate (RR 2.40, 95% CI 1.11–5.18, P = 0.03). There was no influence on secondary outcomes.

Conclusions:

Vitamin D supplementation had no beneficial effect on anti-TB treatment, but it reduced the time to sputum culture conversion in participants with tt genotype of the TaqI vitamin D receptor gene polymorphism and improved the MDR TB sputum culture conversion rate.

Role Of Vitamin-D Supplementation In TB/HIV Co-Infected Patients

OBJECTIVE

This review aimed to assess the role of vitamin D supplementation on the decrement of mortality and morbidity rate among tuberculosis (TB)/human immune deficiency virus (HIV) co-infected clients.Method: Pub Med, google scholar and google search were accessed to find out all document to describe this review article.

RESULTS

Nowadays TB/HIV co-infection has become a major global concern, particularly in low and middle-income countries. Mycobacterium tuberculosis and HIV infections are co-endemic and more susceptible to the progression of TB. Immunosuppression associated with HIV is a strong risk factor for the reactivation of latent TB to the active form. Immune cells like macrophages recognized Mycobacterium tuberculosis through TLR2/1, and it increases the expression of the vitamin D receptor (VDR) and CYP27B1. The synthesis of 1,25-dihydroxy vitamin D promotes VDR-mediated transactivation of the antimicrobial peptide cathelicidin and the killing of intracellular Mycobacterium tuberculosis. Cathelicidins have a direct antimicrobial effect through membrane disruption. Besides, it has also antiviral effects via inhibition of retrovirus (HIV) replication. In fact, as some studies showed, there was a lower induction of cathelicidin in monocytes who have low vitamin D levels.Conclusion: Therefore, vitamin D supplementation can be directly involved in the reduction of TB/HIV co-infection and its progression.

Association of Low Vitamin D with Complications of HIV and AIDS: A literature Review

With the advent of combination antiretroviral therapy (cART), the survival of HIV patients has improved dramatically, but the complications of the disease and treatment have become an important issue in the management of HIV patients. Vitamin-D deficiency is common in HIV patients. Low vitamin-D is associated with different comorbidities in the HIV uninfected general population. In this review, we first briefly describe vitamin D synthesis and mechanism of action and we focus on the epidemiological and clinical data dealing with the relationship between vitamin D deficiency in HIV infection with several comorbidities which has been found to be increasingly common in patients living with HIV infection. We searched the PubMed database using the keywords "HIV," "vitamin D" and other common disorders or conditions that are relatively common in HIV infection. The other conditions included in the search were osteoporosis and fracture, cardiovascular disease, diabetes and insulin resistance, active tuberculosis, hepatitis-C co-infection, and HIV disease progression. Articles presenting original data as well as systematic reviews and met analysis related to HIV population were included in our analysis. Vitamin-D deficiency seems to be associated with several adverse outcomes in HIV patients but a definite cause and effect relationship with vitamin-D is yet to be confirmed in most of the cases. However, the literature supporting the efficacy of vitamin-D supplementation is lacking.

Vitamin D as an Adjunctive Treatment to Standard Drugs in Pulmonary Tuberculosis Patients: An Evidence-Based Case Report

Background

Vitamin D has a prominent role in the body's innate immunity as it is important in the maintenance of macrophages and monocytes and its function in defending against infections. In-vitro studies have established vitamin D's potential role in tuberculosis (TB) infection, in that it restricts Mycobacterium tuberculosis growth, thus implying the potential benefit of vitamin D as an adjunctive treatment for TB. However, clinical trials and reviews have contradicting findings regarding the true clinical efficacy of adjunctive vitamin D, particularly in reducing the sputum conversion rate (SCR).

Objective

This study aims to update the current evidence regarding vitamin D supplementation as an adjunctive treatment in achieving the smear sputum conversion rate (SCR) among pulmonary TB patients.

Method

A comprehensive search was conducted in October 2018 in PubMed-NCBI, MEDLINE-OVID, SCOPUS-Elsevier, and Cochrane. The selection of studies was done as per the predetermined inclusion and exclusion criteria of this EBCR and resulted in the inclusion of 11 eligible studies (8 RCTs and 3 systematic reviews). The selected studies were then critically appraised for their validity, importance, and applicability according to the CEBM (Centre for Evidence-Based Medicine) appraisal tools.

Results

Overall, most of the trials showed no statistically significant changes in terms of the proportion of TB patients with a negative sputum smear conversion in the group treated with an adjunctive therapy vs. the group treated with standard antituberculosis therapy alone. Only one trial showed significant results, which was conducted in a population of TB patients with vitamin D deficiency. Furthermore, overall the reviews showed no significant change in the 8-week sputum smear conversion after treatment within the group given vitamin D in comparison to those who were not.

Conclusion

Vitamin D as adjunctive therapy in TB patients shows no clinical improvement in terms of sputum conversion to antituberculosis management.

No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases

Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.

The role of UV radiation and vitamin D in the seasonality and outcomes of infectious disease

The seasonality of infectious disease outbreaks suggests that environmental conditions have a significant effect on disease risk. One of the major environmental factors that can affect this is solar radiation, primarily acting through ultraviolet radiation (UVR), and its subsequent control of vitamin D production. Here we show how UVR and vitamin D, which are modified by latitude and season, can affect host and pathogen fitness and relate them to the outcomes of bacterial, viral and vector-borne infections. We conducted a thorough comparison of the molecular and cellular mechanisms of action of UVR and vitamin D on pathogen fitness and host immunity and related these to the effects observed in animal models and clinical trials to understand their independent and complementary effects on infectious disease outcome. UVR and vitamin D share common pathways of innate immune activation primarily via antimicrobial peptide production, and adaptive immune suppression. Whilst UVR can induce vitamin D-independent effects in the skin, such as the generation of photoproducts activating interferon signaling, vitamin D has a larger systemic effect due to its autocrine and paracrine modulation of cellular responses in a range of tissues. However, the seasonal patterns in infectious disease prevalence are not solely driven by variation in UVR and vitamin D levels across latitudes. Vector-borne pathogens show a strong seasonality of infection correlated to climatic conditions favoring their replication. Conversely, pathogens, such as influenza A virus, Mycobacterium tuberculosis and human immunodeficiency virus type 1, have strong evidence to support their interaction with vitamin D. Thus, UVR has both vitamin D-dependent and independent effects on infectious diseases; these effects vary depending on the pathogen of interest and the effects can be complementary or antagonistic.

Higher serum 25-hydroxyvitamin D concentrations are associated with active pulmonary tuberculosis in hospitalised HIV infected patients in a low income tropical setting: a cross sectional study

Background

The inherent risk of developing tuberculosis (TB) in HIV- infected individuals is further enhanced by hypovitaminosis D. Interventions that offset HIV-associated immune deterioration potentially arrest disease progression and incidence of opportunistic infections including TB. Despite conflicting reports on association between vitamin D deficiency (VDD) and risk of TB, vitamin D (VD) supplementation remains a promising intervention.

Methods

We conducted a comparative cross-sectional study on 145 HIV⁺/pulmonary TB⁺ (PTB) and 139 HIV⁺/PTB⁻ hospitalised patients to investigate association of vitamin D status and risk of PTB. Stratified random sampling was used to select archived serum specimens from participants enrolled in a randomised controlled trial (RCT) conducted to investigate the impact of using a point-of-care urine lipoarabinomannan strip test for TB diagnosis. PTB status was confirmed using sputum smear microscopy, culture or GeneXpert MTB/RIF. Serum 25-hydroxyvitamin D [25(OH) D] concentrations were assayed by competitive chemiluminescent immunoassay prior to commencement of anti-TB treatment. Effect of VD status on duration of hospital stay and patient outcomes on follow up at 8 weeks were also investigated. Median serum 25(OH) D concentrations were compared using Mann-Whitney test and covariates of serum VD status were assessed using logistic regression analysis.

Results

Overall VDD prevalence in the cohort was 40.9% (95% CI: 35.1–46.8). Median serum 25(OH)D concentrations were significantly higher in HIV⁺/PTB⁺ group (25.3 ng/ml, IQR:18.0–33.7) compared to the HIV⁺/PTB⁻ group (20.4 ng/ml, IQR:14.6–26.9), p = 0.0003. Patients with serum 25(OH) D concentration ≥ 30 ng/ml were 1.9 times more likely to be PTB⁺ compared to those with serum 25(OH) D concentrations < 30 ng/ml (odds ratio (OR) 1.91; 95% CI 1.1–3.2). PTB-related death was associated with higher odds of having 25(OH) D levels≥30 ng/ml. Age, gender, CD4⁺ count, combination antiretroviral therapy (cART) status, efavirenz based cART regimen and length of hospital stay were not associated with vitamin D status.

Conclusions

The finding of an association between higher serum 25(OH) D concentrations and active PTB and TB-related mortality among hospitalised HIV-infected patients in the present study is at variance with the commonly reported association of hypovitaminosis and susceptibility to TB. Our findings though, are in concordance with a small pool of reports from other settings.

Vitamin D supplementation in adolescents with irritable bowel syndrome: Is it useful? A randomized controlled trial

BACKGROUND/AIM

Vitamin D deficiency is common in irritable bowel syndrome (IBS). There is growing interest in the role of vitamin D in pediatric IBS. We aimed to evaluate the effect of vitamin D supplementation in adolescents with IBS and vitamin D deficiency.

PATIENTS AND METHODS

One hundred and twelve adolescents with IBS and vitamin D deficiency were randomly divided into two groups of matched age and sex. The first group received oral vitamin D₃ 2000IU/day for 6 months and the second group received placebo for 6 months. Vitamin D status as well as different IBS score systems (IBS-SSS, IBS-QoL, and total score) were evaluated before and 6 months after treatment.

RESULTS

IBS patients who received vitamin D supplementation for 6 months showed significant improvement in IBS-SSS (P < 0.001), IBS-QoL (P < 0.001), and total score (P = 0.02) compared to IBS placebo group. IBS patients treated with vitamin D showed two folds increase in their serum vitamin D levels (from 17.2 ± 1.3 to 39 ± 3.3) ng/ml with P < 0.001. While in the placebo group, their serum vitamin D levels were not significantly changed (P = 0.66). Vitamin D was tolerated well without any recorded adverse effects during the study period.

CONCLUSION

Vitamin D supplementation can be effective in treating adolescents with IBS and vitamin D deficiency.

A Bacterial Component to Alzheimer's-Type Dementia Seen via a Systems Biology Approach that Links Iron Dysregulation and Inflammagen Shedding to Disease

The progression of Alzheimer's disease (AD) is accompanied by a great many observable changes, both molecular and physiological. These include oxidative stress, neuroinflammation, and (more proximal to cognitive decline) the death of neuronal and other cells. A systems biology approach seeks to organize these observed variables into pathways that discriminate those that are highly involved (i.e., causative) from those that are more usefully recognized as bystander effects. We review the evidence that iron dysregulation is one of the central causative pathway elements here, as this can cause each of the above effects. In addition, we review the evidence that dormant, non-growing bacteria are a crucial feature of AD, that their growth in vivo is normally limited by a lack of free iron, and that it is this iron dysregulation that is an important factor in their resuscitation. Indeed, bacterial cells can be observed by ultrastructural microscopy in the blood of AD patients. A consequence of this is that the growing cells can shed highly inflammatory components such as lipopolysaccharides (LPS). These too are known to be able to induce (apoptotic and pyroptotic) neuronal cell death. There is also evidence that these systems interact with elements of vitamin D metabolism. This integrative systems approach has strong predictive power, indicating (as has indeed been shown) that both natural and pharmaceutical iron chelators might have useful protective roles in arresting cognitive decline, and that a further assessment of the role of microbes in AD development is more than highly warranted.

Vitamin D supplementation decreases immune activation and exhaustion in HIV-1-infected youth

BACKGROUND

Heightened immune activation and exhaustion drive HIV disease progression and comorbidities. Vitamin D has pleiotropic immunomodulatory effects, but little is known about the effects of supplementation in HIV. Our study investigates changes in immune activation and exhaustion markers after 12 months of supplementation in virologically suppressed HIV-infected youth with vitamin D insufficiency.

METHODS

This is a randomized, active-control, double-blind trial investigating with three different vitamin D3 doses (18,000 [standard/active-control dose], 60,000 [moderate dose] and 120,000 IU/month [high dose]) in 8-25-year-old HIV-infected youth on combination antiretroviral therapy with baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations ≤30 ng/ml. Only subjects (n=51) who maintained an undetectable HIV-1 RNA over the 12-month study period were included in this analysis.

RESULTS

Baseline serum 25(OH)D concentrations and immune activation/exhaustion markers were not different between groups. By 12 months, 25(OH)D increased significantly within each dosing group with the greatest increase and most sustained concentrations ≥30 ng/ml in the high-dose group. Overall, all measured markers decreased with CD4 activation (CD4+CD38+HLA-DR+), CD8 activation (CD8+CD38+HLA-DR+), CD4 exhaustion (CD4+CD38+HLA-DR+PD1+) and inflammatory monocytes (CD14+CD16+) reaching statistical significance. When analysed separately, there were no significant decreases in the moderate- or standard-dose groups, but CD4 and CD8 activation and inflammatory monocytes decreased significantly in the high-dose group.

CONCLUSIONS

Vitamin D supplementation decreased markers of T-cell activation/exhaustion and monocyte activation in HIV-infected youth, with subjects given the highest dose (120,000 IU/month) showing the greatest decreases. These data suggest that high-dose vitamin D supplementation may attenuate immune activation and exhaustion, and serve as adjuvant therapy to antiretroviral therapy in HIV. ClinicalTrials.gov identifier: NCT01523496.

Serum Transaminase Concentrations and the Presence of Irritable Bowel Syndrome Are Associated with Serum 25-Hydroxy Vitamin D Concentrations in Adolescent Girls Who Are Overweight and Obese

Background/Aims: Vitamin D deficiency has become endemic globally and its etiology is complex. Few studies have investigated the determinants of serum 25-hydroxy vitamin D (25-OH D). The aim of this study was to investigate the association between lifestyle patterns, liver functional tests (LFTs), and the presence of irritable bowel syndrome (IBS) with serum 25-OH D in apparently healthy girls. Methods: This cross-sectional study was undertaken in 965 adolescent girls aged 12–18 years. IBS was diagnosed using the Rome III questionnaire. An electrochemiluminescence method was used to measure serum 25-OH D. LFTs were measured using commercial kits and an auto analyzer. Linear regression and univariate analyses were performed to determine the association between continuous and categorical variables with serum 25-OH D respectively. Results: Serum 25-OH D was significantly higher in normal weight subjects compared to either overweight or obese subjects (9.5 ± 7.02 vs. 7.9 ± 5.7 ng/mL, p = 0.03). Physical activity level was positively associated with serum 25-OH D in overweight and obese subjects (β = 0.15, p < 0.05). An inverse relationship was found between the presence of IBS and 25-OH D in both normal (β = –1.95, p < 0.05), overweight and obese subjects (β = –1.83, p < 0.05). Serum alanine transaminase (ALT; β = –0.19, p < 0.05) and aspartate transaminase (β = –0.17, p < 0.05) were inversely associated with serum 25-OH in overweight and obese subjects. Conclusions: Individuals with IBS had significantly lower serum 25-OH D concentrations. In addition, there was an inverse association between serum ALT and 25-OH D. Prospective studies, and perhaps interventional trials, will be required to clarify these associations.

Host-Directed Therapeutic Strategies for Tuberculosis

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a leading cause of morbidity and mortality in humans worldwide. Currently, the standard treatment for TB involves multiple antibiotics administered for at least 6 months. Although multiple antibiotics therapy is necessary to prevent the development of drug resistance, the prolonged duration of treatment, combined with toxicity of drugs, contributes to patient non-compliance that can leads to the development of drug-resistant Mtb (MDR and XDR) strains. The existence of comorbid conditions, including HIV infection, not only complicates TB treatment but also elevates the mortality rate of patients. These facts underscore the need for the development of new and/or improved TB treatment strategies. Host-directed therapy (HDT) is a new and emerging concept in the treatment of TB, where host response is modulated by treatment with small molecules, with or without adjunct antibiotics, to achieve better control of TB. Unlike antibiotics, HDT drugs act by directly modulating host cell functions; therefore, development of drug resistance by infecting Mtb is avoided. Thus, HDT is a promising treatment strategy for the management of MDR- and XDR-TB cases as well as for patients with existing chronic, comorbid conditions such as HIV infection or diabetes. Functionally, HDT drugs fine-tune the antimicrobial activities of host immune cells and limit inflammation and tissue damage associated with TB. However, current knowledge and clinical evidence is insufficient to implement HDT molecules as a stand-alone, without adjunct antibiotics, therapeutic modality to treat any form of TB in humans. In this review, we discuss the recent findings on small molecule HDT agents that target autophagy, vitamin D pathway, and anti-inflammatory response as adjunctive agents along with standard antibiotics for TB therapy. Data from recent publications show that this approach has the potential to improve clinical outcome and can help to reduce treatment duration. Thus, HDT can contribute to global TB control programs by potentially increasing the efficiency of anti-TB treatment.

Human Immunology of Tuberculosis

Immunology is a central theme when it comes to tuberculosis (TB). The outcome of human infection with Mycobacterium tuberculosis is dependent on the ability of the immune response to clear or contain the infection. In cases where this fails, the bacterium replicates, disseminates within the host, and elicits a pathologic inflammatory response, and disease ensues. Clinical presentation of TB disease is remarkably heterogeneous, and the disease phenotype is largely dependent on host immune status. Onward transmission of M. tuberculosis to new susceptible hosts is thought to depend on an excessive inflammatory response causing a breakdown of the lung matrix and formation of lung cavities. But this varies in cases of underlying immunological dysfunction: for example, HIV-1 infection is associated with less cavitation, while diabetes mellitus comorbidity is associated with increased cavitation and risk of transmission. In compliance with the central theme of immunology in tuberculosis, we rely on detection of an adaptive immune response, in the form of interferon-gamma release assays or tuberculin skin tests, to diagnose infection with M. tuberculosis. Here we review the immunology of TB in the human host, focusing on cellular and humoral adaptive immunity as well as key features of innate immune responses and the underlying immunological dysfunction which associates with human TB risk factors. Our review is restricted to human immunology, and we highlight distinctions from the immunological dogma originating from animal models of TB, which pervade the field.

Polymorphisms in the vitamin D receptor gene are associated with reduced rate of sputum culture conversion in multidrug-resistant tuberculosis patients in South Africa

BACKGROUND

Vitamin D modulates the inflammatory and immune response to tuberculosis (TB) and also mediates the induction of the antimicrobial peptide cathelicidin. Deficiency of 25-hydroxyvitamin D and single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene may increase the risk of TB disease and decrease culture conversion rates in drug susceptible TB. Whether these VDR SNPs are found in African populations or impact multidrug-resistant (MDR) TB treatment has not been established. We aimed to determine if SNPs in the VDR gene were associated with sputum culture conversion among a cohort of MDR TB patients in South Africa.

METHODS

We conducted a prospective cohort study of adult MDR TB patients receiving second-line TB treatment in KwaZulu-Natal province. Subjects had monthly sputum cultures performed. In a subset of participants, whole blood samples were obtained for genomic analyses. Genomic DNA was extracted and genotyped with Affymetrix Axiom Pan-African Array. Cox proportional models were used to determine the association between VDR SNPs and rate of culture conversion.

RESULTS

Genomic analyses were performed on 91 MDR TB subjects enrolled in the sub-study; 60% were female and median age was 35 years (interquartile range [IQR] 29-42). Smoking was reported by 21% of subjects and most subjects had HIV (80%), were smear negative (57%), and had cavitary disease (55%). Overall, 87 (96%) subjects initially converted cultures to negative, with median time to culture conversion of 57 days (IQR 17-114). Of 121 VDR SNPs examined, 10 were significantly associated (p<0.01) with rate of sputum conversion in multivariable analyses. Each additional risk allele on SNP rs74085240 delayed culture conversion significantly (adjusted hazard ratio 0.30, 95% confidence interval 0.14-0.67).

CONCLUSIONS

Polymorphisms in the VDR gene were associated with rate of sputum culture conversion in MDR TB patients in this high HIV prevalence setting in South Africa.

Vitamin D deficiency is associated with IL-6 levels and monocyte activation in HIV-infected persons

Background

Immune activation plays a key role in HIV pathogenesis. Markers of inflammation have been associated with vitamin D deficiency in the general population. Studies have also demonstrated associations of vitamin D deficiency with increased risk of HIV progression and death. The relationship between persistent inflammation and immune activation during chronic HIV infection and vitamin D deficiency remains unclear.

Methods

Cryopreserved specimens were analyzed from 663 participants at the time of enrollment from the Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy (SUN Study) from 2004 to 2006. Biomarkers of inflammation, atherosclerosis, and coagulation were measured using enzyme-linked immunosorbent assays (ELISAs) and electrochemiluminescence. 25(OH)D, the stable precursor form of vitamin D, was measured using a radioimmunoassay with levels defined as: normal (≥30ng/mL), insufficient (20–29 ng/mL) and deficient (<20 ng/mL). Monocyte phenotypes were assessed by flow cytometry. Linear and logistic regression models were used to determine statistical associations between biomarkers and vitamin D deficiency.

Results

25(OH)D levels were deficient in 251 (38%) participants, insufficient in 222 (34%), and normal in 190 (29%). Patients with vitamin D deficiency, when compared to those with insufficient or normal vitamin D levels, had increased levels of IL-6 (23%; p<0.01), TNF-α (21%, p = 0.03), D-dimer (24%, p = 0.01), higher proportions of CD14^dimCD16+ (22%, p<0.01) and CX3CR1+ monocytes (48%; p<0.001) and decreased frequency of CCR2+ monocytes (-3.4%, p<0.001). In fully adjusted models, vitamin D associations with abnormal biomarker levels persisted for IL-6 levels and CX3CR1+ and CCR2+ phenotypes.

Conclusions

Vitamin D deficiency is associated with greater inflammation and activated monocyte phenotypes. The role of vitamin D deficiency in persistent immune activation and associated complications during chronic HIV disease should be further evaluated as a possible target for intervention.

Vitamin D and activated vitamin D in tuberculosis in equatorial Malaysia: a prospective clinical study

Background

Vitamin D deficiency (low plasma 25-hydroxyvitamin D [25D] concentration) is often reported in tuberculosis. Adjunctive vitamin D has been tested for its potential to improve treatment outcomes, but has proven largely ineffective. To better understand vitamin D in tuberculosis, we investigated determinants of 25D and its immunologically active form, 1,25-dihydroxyvitamin D (1,25D), their inter-relationship in tuberculosis, longitudinal changes and association with outcome.

Methods

In a prospective observational study of adults with smear-positive pulmonary tuberculosis in Sabah, Malaysia, we measured serial 25D, 1,25D, vitamin D-binding protein (VDBP), albumin, calcium, parathyroid hormone, chest x-ray, week 8 sputum smear/culture and end-of-treatment outcome. Healthy control subjects were enrolled for comparison.

Results

1,25D was elevated in 172 adults with tuberculosis (mean 229.0 pmol/L, 95% confidence interval: 215.4 - 242.6) compared with 95 controls (153.9, 138.4-169.4, p < 0.001), directly proportional to radiological severity (p < 0.001), and fell rapidly within one week of treatment commencement. Tuberculosis patients with higher baseline 1,25D achieved significantly higher percentage weight gain over time, including when controlling for baseline weight, however persistently elevated 1,25D was associated with worse residual x-ray changes and lower end-of-treatment BMI. 1,25D was inversely associated with PTH (p < 0.001), consistent with the extra-renal origin of the 1,25D. 25D did not differ between tuberculosis patients (mean 63.9 nmol/L, 95% CI: 60.6 - 67.3) and controls (61.3, 57.2- 65.3, p = 0.24), and was unassociated with outcomes. Among tuberculosis patients in multivariable analyses, sex, age and VDBP were associated with 25D, and age and albumin with 1,25D. 1,25-dihydroxyvitamin was not significantly asscociated with 25D. Vitamin D deficiency <25 nmol/L was uncommon, occurring in only five TB patients; 1,25D was elevated in three of them.

Conclusions

In an equatorial setting, high extra-renal production of 1,25D was seen in tuberculosis, including in individuals with 25D in the deficient range; however, severe 25D deficiency was uncommon. Baseline elevation of 1,25D, a marker of macrophage activation, was associated with better weight gain but persistent elevation of 1,25D was associated with worse radiological and BMI outcomes. 1,25D warrants testing in larger datasets including TB patients less responsive to treatment, such as multi-drug resistant TB, to test its utility as a marker of tuberculosis severity and treatment response.

Vitamin D Status and Its Consequences for Health in South Africa

In this review, reports were retrieved in which vitamin D status, as assessed by serum 25-hydroxyvitamin D [25(OH)D] levels, was measured in South African population groups with varied skin colours and ethnicities. Healthy children and adults were generally vitamin D-sufficient [25(OH)D level >50 nmol/L] but the majority of those aged above 65 years were deficient. A major role for exposure to solar ultraviolet radiation (UVR) in determining 25(OH)D levels was apparent, with the dietary contribution being minor. Limited data exist regarding the impact of recent changes in lifestyles on vitamin D status, such as urbanisation. With regard to disease susceptibility, 11 of 22 relevant publications indicated association between low 25(OH)D levels and disease, with deficiency most notably found in individuals with tuberculosis and HIV-1. Information on the relationship between vitamin D receptor variants and ethnicity, disease or treatment response in the South African population groups demonstrated complex interactions between genetics, epigenetics and the environment. Whether vitamin D plays an important role in protection against the range of diseases that currently constitute a large burden on the health services in South Africa requires further investigation. Only then can accurate advice be given about personal sun exposure or dietary vitamin D supplementation.

Effect of vitamin D on gastrointestinal symptoms and health-related quality of life in irritable bowel syndrome patients: a randomized double-blind clinical trial

BACKGROUND

Low-grade mucosal inflammation and immune activation are involved in the pathogenesis of irritable bowel syndrome (IBS). Furthermore, IBS symptoms are associated with a significantly higher prevalence of psychological distress, which in itself results into an impaired quality of life (QoL). Vitamin D could ameliorate the symptoms of patients suffering from IBS through its beneficial effects on psychological factors and inflammation.

METHODS

A total of 90 IBS patients participated in this double-blind, randomized, placebo-controlled study. Participants were randomly selected to receive either 50 000 IU vitamin D3 or a placebo fortnightly for a period of 6 months. Patients reported their IBS symptoms at the baseline and monthly during intervention periods. The IBS severity score system (IBSSS) and IBS-specific QoL questionnaires were used at the baseline and postintervention.

KEY RESULTS

Over the 6-month intervention period, a significantly greater improvement in IBS symptoms such as abdominal pain and distention, flatulence, rumbling, and overall gastrointestinal (GI) symptoms (except dissatisfaction with bowel habits) was observed in the patients receiving vitamin D as compared to the placebo group. The IBSSS and the IBS-QoL scores in the vitamin D group significantly improved compared to the placebo group postintervention (mean IBSSS score change: -53.82 ± 23.3 vs -16.85 ± 25.01, p < 0.001, respectively; mean IBS-QoL score change: 14.26 ± 3 vs 11 ± 2.34, p < 0.001, respectively).

CONCLUSIONS & INFERENCES

Vitamin D seems to be an effective and safe option to improve QoL and symptoms of IBS. ClinicalTrials.gov (NCT02579902).

Increased risk of latent tuberculous infection among persons with pre-diabetes and diabetes mellitus

SETTING

Although diabetes mellitus (DM) is an established risk factor for active tuberculosis (TB) disease, little is known about the association between pre-DM, DM, and latent tuberculous infection (LTBI).

OBJECTIVE

To estimate the association between DM and LTBI.

DESIGN

We conducted a cross-sectional study among recently arrived refugees seen at a health clinic in Atlanta, GA, USA, between 2013 and 2014. Patients were screened for DM using glycosylated-hemoglobin (HbA1c), and for LTBI using the QuantiFERON(®)-TB (QFT) test. HbA1c and QFT results, demographic information, and medical history were abstracted from patient charts.

RESULTS

Among 702 included patients, 681 (97.0%) had HbA1c and QFT results. Overall, 54 (7.8%) patients had DM and 235 (33.8%) had pre-DM. LTBI was prevalent in 31.3% of the refugees. LTBI prevalence was significantly higher (P < 0.01) among patients with DM (43.4%) and pre-DM (39.1%) than in those without DM (25.9%). Refugees with DM (adjusted OR [aOR] 2.3, 95%CI 1.2-4.5) and pre-DM (aOR 1.7, 95%CI 1.1-2.4) were more likely to have LTBI than those without DM.

CONCLUSION

Refugees with DM or pre-DM from high TB burden countries were more likely to have LTBI than those without DM. Dysglycemia may impair the immune defenses involved in preventing Mycobacterium tuberculosis infection.

Vitamin D as Adjunctive Host-Directed Therapy in Tuberculosis: A Systematic Review

Vitamin D plays an important role in innate defenses against intracellular pathogens. Seasonal vitamin D insufficiency (VDI) due to reduced sun exposure far from the equator increases tuberculosis risk. Eight randomized controlled trials examined vitamin D as adjunctive therapy during tuberculosis treatment. The studies varied substantially regarding patient genetic backgrounds, the extent of baseline VDI, the administered dose, the study endpoints, and the quality of the reported data. One carefully performed study in which moderately large vitamin D doses were given to markedly VDI patients found a benefit sufficient to support shortening treatment from 6 to 4 months, although other similar studies did not. Vitamin D is thought to have anti-inflammatory effects. However, 2 studies reported 3 vitamin D recipients with severe paradoxical inflammatory reactions. Future studies of vitamin D in tuberculosis in patients with specific genetic backgrounds must monitor these events closely to determine their risks and underlying mechanisms.

Vitamin D-Regulated MicroRNAs: Are They Protective Factors against Dengue Virus Infection?

Over the last few years, an increasing body of evidence has highlighted the critical participation of vitamin D in the regulation of proinflammatory responses and protection against many infectious pathogens, including viruses. The activity of vitamin D is associated with microRNAs, which are fine tuners of immune activation pathways and provide novel mechanisms to avoid the damage that arises from excessive inflammatory responses. Severe symptoms of an ongoing dengue virus infection and disease are strongly related to highly altered production of proinflammatory mediators, suggesting impairment in homeostatic mechanisms that control the host's immune response. Here, we discuss the possible implications of emerging studies anticipating the biological effects of vitamin D and microRNAs during the inflammatory response, and we attempt to extrapolate these findings to dengue virus infection and to their potential use for disease management strategies.

Vitamin D Status in Botswana Children Under 2 Years Old With and Without Active Tuberculosis

Additional strategies are needed to prevent and treat tuberculosis (TB). Although vitamin D may have antimycobacterial effects, it is unknown whether low vitamin D status confers a risk for active TB in African children. This case-control study assessed serum 25-hydroxyvitamin D (25(OH)D) concentration in children with and without active TB in Gaborone, Botswana. A total of 80 children under 2 years old with and without active TB, seen at hospitals and clinics in the greater Gaborone area between September 2010 and November 2012, were enrolled. Of these, 39 cases did not differ from the 41 controls in median 25(OH)D levels (P = 0.84). The 25(OH)D was < 20 ng/mL in 8/39 (21%) cases and 7/41 (17%) controls (P = 0.69, χ(2)). Univariate analyses of subject clinical characteristics (other than 25(OH)D levels) showed that any degree of weight loss was associated with a diagnosis of TB (P = 0.047). Other clinical characteristics, including age (P = 0.08) or weight below third percentile (P = 0.58), showed no association with TB. There was no significant difference in vitamin D status between children under 2 years old with and without active TB. Lower vitamin D status did not appear to be a risk factor for TB in this small Gaborone cohort.

Elevated serum 25-hydroxy (OH) vitamin D levels are associated with risk of TB progression in Gambian adults

Background

Vitamin D is essential in the host defence against tuberculosis (TB) as an immune modulator. The aim of this study was to determine the level of 25-hydroxyvitamin D (25 (OH) D) from adult TB index cases before and after treatment and their exposed household contacts (HHC) in The Gambia.

Methods

Serum from adult index TB cases and their TB-exposed household contacts (HHC) was analysed for 25(OH) D and Vitamin D binding protein (VDBP) concentrations. Tuberculin skin test (TST) status was used as a measure of Mycobacterium tuberculosis (Mtb) infectivity in the HHC. In addition, HHC who later progressed to active TB (incident cases) were assessed alongside non-progressors to determine the influence of 25 (OH) D levels on TB risk.

Results

Eighty-three TB cases, 46 TST+ and 52 TST− HHC were analysed. Generally levels of 25(OH) D were considered insufficient in all subjects. However, median levels of 25(OH) D and VDBP were significantly higher in TB cases compared to both TST+ and TST− HHC at recruitment and were significantly reduced after TB therapy (p < 0.0001 for all). In addition, levels of serum 25(OH) D at recruitment were significantly higher in TB progressors compared to non-progressors (median (IQR): 25.0(20.8–29.2) in progressors and 20.3 (16.3–24.6) ng/ml in non-progressors; p = 0.007).

Conclusion

In The Gambia, an equatorial country, 25(OH) D levels are higher in serum of TB progressors and those with active disease compared to latently infected and uninfected subjects. These results contrast to findings in non-equatorial countries.

Dietary Vitamin D3 Suppresses Pulmonary Immunopathology Associated with Late-Stage Tuberculosis in C3HeB/FeJ Mice

Tuberculosis (TB) is a significant human disease caused by inhalation of Mycobacterium tuberculosis. Left untreated, TB mortality is associated with a failure to resolve pulmonary immunopathology. There is currently widespread interest in using vitamin D3 (VitD3) as an adjunct therapy for TB because numerous in vitro studies have shown that VitD3 has direct and indirect mycobactericidal activities. However, to date, there have been no in vivo studies addressing whether VitD3 affects experimental TB outcome. In this study, we used C3HeB/FeJ mice to determine whether dietary VitD3 influences the outcome of experimental TB. We observed that although M. tuberculosis burdens did not differ between mice on a VitD3-replete diet (VitD(HI) mice) and mice on a VitD3-deficient diet (VitD(LO) mice), the inflammatory response in VitD(HI) mice was significantly attenuated relative to VitD(LO) controls. Specifically, the expression of multiple inflammatory pathways was reduced in the lungs at later disease stages as were splenocyte IL12/23p40 and IFN-γ levels following ex vivo restimulation. Dietary VitD3 also suppressed the accumulation of T cells in the mediastinal lymph nodes and lung granulomatous regions while concomitantly accelerating the accumulation of F4/80(+) and Ly6C/Ly6G(+) lineages. The altered inflammatory profile of VitD(HI) mice also associated with reductions in pulmonary immunopathology. VitD receptor-deficient (vdr(-/-)) radiation bone marrow chimeras demonstrate that reductions in pulmonary TB immunopathology are dependent on hematopoietic VitD responsiveness. Collectively, our data support a model wherein the in vivo role of VitD3 during TB is not to promote M. tuberculosis killing but rather to function through hematopoietic cells to reduce M. tuberculosis-elicited immunopathology.

Acquired immunodeficiencies and tuberculosis: focus on HIV/AIDS and diabetes mellitus

The spread of human immunodeficiency virus (HIV) infection within Africa led to marked increases in numbers of cases of tuberculosis (TB), and although the epidemic peaked in 2006, there were still 1.8 million new cases in 2013, with 29.2 million prevalent cases. Half of all TB cases in Africa are in those with HIV co-infection. A brief review of the well-documented main immunological mechanisms of HIV-associated increased susceptibility to TB is presented. However, a new threat is facing TB control, which presents itself in the form of a rapid increase in the number of people living with type II diabetes mellitus (T2DM), particularly in areas that are already hardest hit by the TB epidemic. T2DM increases susceptibility to TB threefold, and the TB burden attributable to T2DM is 15%. This review addresses the much smaller body of research information available on T2DM-TB, compared to HIV-TB comorbidity. We discuss the altered clinical presentation of TB in the context of T2DM comorbidity, changes in innate and adaptive immune responses, including lymphocyte subsets and T-cell phenotypes, the effect of treatment of the different comorbidities, changes in biomarker expression and genetic predisposition to the respective morbidities, and other factors affecting the comorbidity. Although significant gains have been made in improving our understanding of the underlying mechanisms of T2DM-associated increased susceptibility, knowledge gaps still exist that require urgent attention.