Back to the future: a new look at 'old' vitamin D

The role of vitamin D in periodontal health and disease

Vitamin D plays an essential role in calcium and bone metabolism, immune regulation and possesses profound anti-inflammatory effects. Evidence suggests that low serum vitamin D is associated with increased severity of periodontitis, a chronic inflammatory condition characterised by destruction of the supporting tissues surrounding the tooth, which has several shared risk factors with other chronic non-communicable diseases. The biological functions of vitamin D are mediated by its strong anti-microbial, anti-inflammatory, and host modulatory properties. Experimental periodontitis models involving targeted deletion of 1α-hydroxylase, the enzyme responsible for the conversion of inactive substrate to active 1,25(OH)₂ D₃ (calcitriol), showed augmented alveolar bone loss and gingival inflammation. Vitamin D receptor (VDR) gene polymorphisms have also been associated with increased severity of periodontitis. Thus, the involvement of vitamin D in the pathogenesis of periodontitis is biological plausible. Clinical studies have consistently demonstrated an inverse relationship between serum 25OHD₃ and periodontal disease inflammation. However, due to the paucity of well-designed longitudinal studies, there is less support for the impact of vitamin D status on periodontal disease progression and tooth loss. The evidence emphasises the importance of maintaining vitamin D sufficiency in supporting periodontal health. This review aims to first examine the biological mechanisms by which vitamin D might influence the pathogenesis of periodontal disease and second, discuss the clinical evidence which implicate the role of vitamin D in periodontal disease.

Vitamin D receptor genetic polymorphisms in severe and recurrent tuberculosis in children

AIM

To analyze the genetic polymorphisms of vitamin D receptor FokI, TaqI, ApaI and BsmI gene polymorphisms in children with severe and recurrent tuberculosis (TB).

METHODS

A prospective, observational study was conducted in 35 children with severe and recurrent TB referred to our Pediatric TB clinic at a tertiary referral center for children. The blood samples were analysed for genetic polymorphisms of Vitamin D receptor with respect to FokI, TaqI, ApaI and BsmI genotypes and their individual alleles and association of various clinical and laboratory parameters were analysed.

RESULT

Ten (28.6%) children had recurrent TB and 26 (74.3%) had severe TB. The severity of TB was not associated with Ff and ff polymorphism of FokI (Odd's ratio 7.88) as compared to no FokI polymorphism. Absence of FokI polymorphism was associated with recurrent lymph node TB (Odds ratio 3.429). Presence of Tt polymorphism of TaqI (p = 0.04) and Fok1 Polymorphism [Odds ratio 7.88] were not associated with recurrent TB.

CONCLUSION

Recurrent TB was absent in presence of Tt polymorphism of TaqI. Severe TB was not associated polymorphism of Vitamin D receptor polymorphisms.

Vitamin D Status and Its Role in First-Time and Recurrent Urinary Tract Infections in Children: A Case-Control Study

Vitamin D has emerged as a key factor in innate immunity. Its involvement in the pathogenesis of urinary tract infections (UTIs) has gained a lot of attention recently. The objective of this study is to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) levels and first-time or recurrent UTIs in children. A prospective, case-control study was conducted on 101 pediatric patients, who were divided into two groups: 59 patients with UTIs and 42 age-matched healthy controls. Serum 25(OH)D was determined in each child and expressed in ng/mL. Vitamin D presented significantly lower values in study group subjects than in healthy controls (p < 0.01). Moreover, a significantly higher prevalence of vitamin D insufficiency and deficiency was found in children with UTIs (p < 0.01). Patients with recurrent UTIs presented significantly lower levels of vitamin D than those with first-time UTIs (p = 0.04). Urinary tract abnormalities did not seem to exercise an additional effect upon vitamin D levels within the study group. In conclusion, first-time and recurrent UTIs are associated with lower vitamin D levels. Further studies are necessary to validate our findings, as well as future longitudinal research regarding efficacy of vitamin D supplementation in children with UTIs.

Immunomodulatory Effects of Vitamin D Supplementation in a Deficient Population

In addition to its canonical functions, vitamin D has been proposed to be an important mediator of the immune system. Despite ample sunshine, vitamin D deficiency is prevalent (>80%) in the Middle East, resulting in a high rate of supplementation. However, the underlying molecular mechanisms of the specific regimen prescribed and the potential factors affecting an individual's response to vitamin D supplementation are not well characterized. Our objective is to describe the changes in the blood transcriptome and explore the potential mechanisms associated with vitamin D3 supplementation in one hundred vitamin D-deficient women who were given a weekly oral dose (50,000 IU) of vitamin D3 for three months. A high-throughput targeted PCR, composed of 264 genes representing the important blood transcriptomic fingerprints of health and disease states, was performed on pre and post-supplementation blood samples to profile the molecular response to vitamin D3. We identified 54 differentially expressed genes that were strongly modulated by vitamin D3 supplementation. Network analyses showed significant changes in the immune-related pathways such as TLR4/CD14 and IFN receptors, and catabolic processes related to NF-kB, which were subsequently confirmed by gene ontology enrichment analyses. We proposed a model for vitamin D3 response based on the expression changes of molecules involved in the receptor-mediated intra-cellular signaling pathways and the ensuing predicted effects on cytokine production. Overall, vitamin D3 has a strong effect on the immune system, G-coupled protein receptor signaling, and the ubiquitin system. We highlighted the major molecular changes and biological processes induced by vitamin D3, which will help to further investigate the effectiveness of vitamin D3 supplementation among individuals in the Middle East as well as other regions.

Association between polymorphisms in the vitamin D receptor and susceptibility to multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is a neurodegenerative chronic inflammatory. Mutations in the vitamin D receptor (VDR) gene can substantially affect serum vitamin D levels or alter its functionality, and can consequently increase susceptibility to developing MS. The objective of this study was to evaluate the association between polymorphisms in the VDR gene and risk of MS in a (Spanish) Caucasian population.

PATIENTS AND METHODS

We conducted a retrospective case-control study comprising 209 patients with relapsing-remitting multiple sclerosis (RRMS) and 836 controls of Caucasian origin from southern Spain. The ApaI (rs7975232), BsmI (rs1544410), Cdx2 (rs11568820), FokI (rs2228570), and TaqI (rs731236) gene polymorphisms were determined by allelic discrimination real-time PCR using TaqMan probes.

RESULTS

The recessive logical regression model, adjusted for age and sex, revealed that the TT genotype for VDR FokI (rs2228570) polymorphism was associated with higher risk of MS (P = 0.0150; OR = 1.82; 95% CI = 1.12-2.94; TT vs. CT + CC). No association between the other polymorphisms and development of MS was found in any of the models analyzed. The haplotype analysis, adjusted for age, smoking, and sex, did not find any statistically significant association between the haplotypes analyzed and risk of MS.

CONCLUSIONS

The VDR FokI (rs2228570) polymorphism was significantly associated with developing MS. We found no influence of the ApaI (rs7975232), BsmI (rs1544410), Cdx2 (rs11568820), FokI (rs2228570), and TaqI (rs731236) gene polymorphisms on the risk of developing MS in our patients.

The Influence of Vitamin D on Neurodegeneration and Neurological Disorders: A Rationale for its Physio-pathological Actions

Vitamin D is a steroid hormone implicated in the regulation of neuronal integrity and many brain functions. Its influence, as a nutrient and a hormone, on the physiopathology of the most common neurodegenerative diseases is continuously emphasized by new studies. This review addresses what is currently known about the action of vitamin D on the nervous system and neurodegenerative diseases such as Multiple Sclerosis, Alzheimer's disease, Parkinson's disease and Amyotrophic Lateral Sclerosis. Further vitamin D research is necessary to understand how the action of this "neuroactive" steroid can help to optimize the prevention and treatment of several neurological diseases.

Vitamin D-binding protein as a biomarker to confirm specific clinical diagnoses

Introduction: Vitamin D-binding protein (DBP) performs a variety of functions as a transporter for various ligands and takes part in a number of systemic and local physiological and pathological processes. The knowledge about the pathomechanisms of this protein involvement justifies its use as a biomarker to confirm specific clinical diagnoses suggested by nonspecific signs and symptoms.Areas covered: DBP has properties of both systemic laboratory parameters measured in the blood plasma and specific parameters measured in variety of physiological fluids to assess local changes in specific body organs. Articles published in English between 1993 and 2019 were searched for in PubMed using terms DBP, vitamin D, and metabolites, inflammation. DBP is a transport protein and a regulator of immune and inflammatory processes.Expert opinion: DBP capacity for transporting numerous ligands and co-involvement of DBP in immune and inflammatory processes suggest that DBP may be used in laboratory diagnostics as a specific parameter to confirm pathomechanisms of several systemic diseases and local conditions. Changes in the concentration of DBP present in a variety of clinical material may provide valuable information for use in assessing the severity and treatment of pathological processes.

Changes in saliva of dogs with canine leishmaniosis: A proteomic approach

In the present study, a quantitative proteomic approach to study changes in saliva proteins associated with canine leishmaniosis (CanL) was performed. For this, canine salivary proteins were analysed and compared between dogs before (T0) and after (T1) experimental infection with Leishmania infantum by high-throughput label-based quantitative LC-MS/MS proteomic approach and bioinformatic analysis of the in silico inferred interactome protein network was created from the initial list of differential proteins. More than 2000 proteins were identified, and of the 90 differentially expressed proteins between T0 and T1, 12 were down-regulated with log2 fold change lower than -0.5849, and 19 were up-regulated with log2 fold change greater than 0.5849. This study provides evidence of changes in salivary proteome that can occur in canine leishmaniosis and revealed biological pathways in saliva modulated in canine leishmaniosis with potential for further targeted research.

Significance of urinary C-megalin excretion in vitamin D metabolism in pre-dialysis CKD patients

Serum 1,25(OH)₂D and 24,25(OH)₂D are decreased in CKD. Megalin in proximal tubular epithelial cells reabsorbs glomerular-filtered 25(OH)D-DBP complex to convert 25(OH)D to 1,25(OH)₂D and 24,25(OH)₂D. Urinary C-megalin excretion is increased via exocytosis from injured nephrons overloaded with megalin-mediated protein metabolism. This study investigated the significance of urinary C-megalin excretion in vitamin D metabolism in 153 pre-dialysis CKD patients. Urinary C-megalin was positively associated with urinary protein, β₂MG and α₁MG, and exhibited negative correlations with serum 25(OH)D, 1,25(OH)₂D and 24,25(OH)₂D. Multiple regression analysis showed that urinary C-megalin had a significantly negative association with 25(OH)D. Serum 1,25(OH)₂D and 24,25(OH)₂D, as well as 1,25(OH)₂D/25(OH)D and 24,25(OH)₂D/25(OH)D ratios, showed positive correlations with eGFR. Additionally, wholePTH was positively associated with 1,25(OH)₂D/25(OH)D and 1,25(OH)₂D/24,25(OH)₂D, while FGF23 was positively associated with 24,25(OH)₂D/25(OH)D and negatively with 1,25(OH)₂D/24,25(OH)₂D. Urinary C-megalin emerged as an independent factor positively associated with 1,25(OH)₂D/25(OH)D and 1,25(OH)₂D/24,25(OH)₂D. Although 1,25(OH)₂D and 24,25(OH)₂D are decreased in CKD patient serum, our findings suggest that PTH and FGF23 retain their effects to regulate vitamin D metabolism even in the kidneys of these patients, while production of 1,25(OH)₂D and 24,25(OH)₂D from 25(OH)D is restricted due to either impairment of megalin-mediated reabsorption of the 25(OH)D-DBP complex or reduced renal mass.

Impact of a Vitamin D Replacement Algorithm in Children and Young Adults With Acute Lymphoblastic Leukemia

BACKGROUND

Pediatric cancer patients have a high prevalence of vitamin D deficiency. Children and young adults with acute lymphoblastic leukemia are at high risk for associated poor bone outcomes due to contributing effects of chemotherapy and supportive care. Evidence-based vitamin D guidelines are lacking in this population.

MATERIALS AND METHODS

This is a retrospective study following the implementation of an institutional guideline for standardized monitoring and supplementing vitamin D based on 25-hydroxyvitamin D levels and patient age. Goal 25-hydroxyvitamin D level was defined as ≥30 ng/mL and levels were checked every 3 months.

RESULTS

Over a period of 22 months, 69 patients (median age, 6.7 y) were included. At diagnosis, 42 patients (60.8%) were insufficient. Among insufficient patients at diagnosis, 83.3% became sufficient at first repeat level following supplementation. At completion of the study 95.6% of patients were sufficient. Insufficiency was more common in winter than summer at baseline (74.3% vs. 47.1%, P=0.03), though the impact of seasonality was overcome following the algorithm. Throughout the study 4 patients had supratherapeutic but nontoxic levels.

CONCLUSIONS

Vitamin D replacement guidelines implemented in the pediatric and young adult acute lymphoblastic leukemia population markedly increased the percentage of vitamin D sufficient patients in a short period of time.

Low Vitamin D Level on Admission for Burn Injury Is Associated With Increased Length of Stay

Currently, there have been few studies that have evaluated the incidence of vitamin D deficiency in adult burn patients or correlated vitamin D levels with burn-related outcomes. The primary objective of the study was to identify the incidence of vitamin D deficiency and insufficiency in an adult burn population. The secondary objective was to determine the impact of vitamin D deficiency and insufficiency on clinical outcomes in burn care. A single-center, retrospective, and observational cohort analysis of adult patients admitted for initial management of burn injury, who had a 25-hydroxyvitamin D (25D) level measured on admission, was performed. Patients were categorized as vitamin D deficient (25D <10 ng/ml), insufficient (10-29 ng/ml), or sufficient (30-100 ng/ml) based on admission measurements. Clinical outcomes including complications, intensive care unit (ICU) and hospital length of stay (LOS), and survival were compared between patients with vitamin D deficiency/insufficiency and patients with vitamin D sufficiency. Three-hundred and eighteen patients were eligible for evaluation. Admission 25D level correlated with deficiency in 46 patients (14.5%), insufficiency in 207 (65.1%), and normal in 65 (20.4%). Patients with vitamin D deficiency or insufficiency experienced higher rates of complications and longer ICU and hospital LOS compared with those with normal vitamin D levels. A large proportion of patients with burn injury presented with vitamin D insufficiency and deficiency which was associated with poor outcomes, including prolonged ICU and hospital LOS. Additional studies are needed to further describe the relationship between vitamin D status and clinical outcomes.

Influence of vitamin D on key bacterial taxa in infant microbiota in the KOALA Birth Cohort Study

Vitamin D has immunomodulatory properties giving it the potential to affect microbial colonization of the intestinal tract. We investigated whether maternal vitamin D supplemention, maternal plasma 25-hydroxyvitamin D concentration, or direct supplementation of the infant influences key bacterial taxa within microbiota of one month old infants. Infant and maternal vitamin D supplement use was ascertained via questionnaires. Maternal plasma 25-hydroxyvitamin D was determined at approximately the 36^th week of pregnancy. In 913 one month old infants in the prospective KOALA Birth Cohort Study, fecal Bifidobacterium spp., Escherichia coli, Clostridium difficile, Bacteroides fragilis group, Lactobacillus spp. and total bacteria were quantified with real-time polymerase chain reaction assays targeting 16S rRNA gene sequences. The association between vitamin D exposure and prevalence or abundance of a specific bacterial group or species was analyzed using logistic or linear regression, respectively. There was a statistically significant negative linear trend between counts of Bifidobacterium spp. and levels of maternal vitamin D supplementation and maternal 25-hydroxyvitamin D quintiles, respectively. In addition, a positive linear trend between quintile groups and B. fragilis group counts was observed. Lower counts of C. difficile were associated with vitamin D supplementation of breast fed infants whose mothers were more likely to adhere to an alternative lifestyle in terms of, e.g., dietary habits. These data suggest that vitamin D influences the abundance of several key bacterial taxa within the infant microbiota. Given that intestinal microbiotic homeostasis may be an important factor in the prevention of immune mediated diseases and that vitamin D status is a modifiable factor, further investigation of the impact of postnatal vitamin D supplementation should be conducted in older infants.

Parathyroidectomy: is vitamin D a player for a good outcome?

Background: The field of parathyroidectomy (PTx) is complex and brings together many specialists. Even if the surgical approaches changed from classical to minimally invasive PTx, a good outcome is correlated with an adequate localization before and during PTx, while blood assays, such as parathormone (PTH) or 25-hydroxyvitamin D, become useful additional markers. Aim. Specific aspects related to parathyroidectomy and vitamins D (VD) were introduced. Material and Method. The article represents a PubMed-based narrative review. Results. The growing evidence regarding the high prevalence of hypovitaminosis D and early detection of primary hyperparathyroidism (HPT) requires a particular attention to the association of these two disorders, which may be incidental, but some common pathogenic links are displayed. Low VD stimulates PTH production as a secondary or even tertiary type of HPT diagnosis. VD deficiency is associated with larger parathyroid adenomas and higher levels of PTH before and after surgery for primary HPT. Asymptomatically and normocalcemic forms of primary HPT, which are not immediately referred to PTx, require a normalization of the VD levels. VD supplements are safe under some serum calcium cutoffs and offer a better outcome after PTx. However, primary HPT is cured by surgery and, if the indication is well established, this should not be delayed too long to replace VD. Up to half of PTx cases may experience increased PTH levels after surgery, but most of these are transitory if rapid VD correction is done and only a few remaining cases will eventually develop persistent / recurrent primary HPT. Conclusion. A close following of 25-hydroxivitamin D represents one of the keys for a good outcome in the field of parathyroid surgery. Abbreviations: HPT = hyperparathyroidism, MEN = Multiple Endocrine Neoplasia Syndrome, PTx = parathyroidectomy, PTH = parathormone, VD = Vitamin D.

Vitamin D receptor gene associations with pulmonary tuberculosis in a Tibetan Chinese population

BACKGROUND

The vitamin D receptor (VDR) mediates the immunological function of vitamin D3, which activates macrophages, and vitamin D deficiency has been linked to tuberculosis risk. Single nucleotide polymorphisms (SNPs) in VDR may influence the function of vitamin D and susceptibility to tuberculosis.

METHODS

This study included 217 patients with pulmonary tuberculosis (PTB) and 383 healthy subjects in a Tibetan Chinese population living in and near Xi'an. Association analyses of SNPs in VDR were performed with the SPSS 17.0 statistical packages, SNP stats software, Haploview software package (version 4.2), and the SHEsis software platform.

RESULTS

Our results revealed a correlation between three SNPs (rs11574143, odds ratio [OR]: 1.47, 95 % confidence interval [CI]: 1.11 - 1.94, p = 0.006, p-adjust = 0.030; rs11574079, OR: 0.48, 95 % CI: 0.25 - 0.92, p = 0.023, p-adjust = 0.115; rs11168287, OR: 2.55, 95 % CI: 2.00 - 3.25, p = 1.730E-14, p-adjust = 0.865E-13) and PTB based on Chi-square tests. We observed the allele "A" of rs11574143 and rs11168287 increased the PTB risk and the allele "A" of rs11574079 provided a protective effect against PTB.

CONCLUSIONS

The goal of this study was the identification of putative associations between five SNPs (rs11574143, rs7975232, rs11574079, rs3819545 and rs11168287) in VDR and susceptibility to PTB. Our findings demonstrated associations between VDR polymorphisms and PTB development.

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.

Poor growth, thyroid dysfunction and vitamin D deficiency remain prevalent despite reduced intensity chemotherapy for hematopoietic stem cell transplantation in children and young adults

Myeloablative conditioning regimens for hematopoietic stem cell transplant (HSCT) are known to affect endocrine function, but little is known regarding reduced intensity conditioning (RIC) regimens. We retrospectively reviewed 114 children and young adults after single RIC HSCT. The analysis was grouped by age (<2 and ⩾2 years) and diagnosis (hemophagocytic lymphohistiocystosis/X-linked lymphoproliferative syndrome (HLH/XLP), other immune disorders, metabolic/genetic disorders). All groups displayed short stature by mean height-adjusted Z-score (HAZ) before (-1.29) and after HSCT (HAZ -1.38, P=0.47). After HSCT, younger children with HLH/XLP grew better (HAZ -3.41 vs -1.65, P=0.006), whereas older subjects had decline in growth (HAZ -0.8 vs -1.01, P=0.06). Those with steroid therapy beyond standard GVHD prophylaxis were shorter than those without (P 0.04). After HSCT, older subjects with HLH/XLP became thinner with a mean body mass index (BMI) Z-score of 1.20 vs 0.64, P=0.02, and similar to metabolic/genetic disorders (BMI-Z= 0.59 vs -0.99, P<0.001). BMI increased among younger children in these same groups. Thyroid function was abnormal in 24% (18/76). 25-OH vitamin D levels were insufficient in 73% (49/65), with low bone mineral density in 8 of 19 evaluable subjects. Despite RIC, children and young adults still have significant late endocrine effects. Further research is required to compare post-transplant endocrine effects after RIC to those after standard chemotherapy protocols.

The NRAMP1, VDR, TNF-α, ICAM1, TLR2 and TLR4 gene polymorphisms in Iranian patients with pulmonary tuberculosis: A case-control study

The innate immune response drives early events in Mycobacterium tuberculosis infection. Since human genetic variation is an important determinant in the outcome of infection with M. tuberculosis, we typed polymorphisms in the innate immune molecules, such as natural-resistance-associated macrophage protein 1 (NRAMP1), Vitamin D receptor (VDR), Tumor necrosis factor alpha (TNF-α), intercellular adhesion molecule1 (ICAM-1), Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) in a case-control study of pulmonary tuberculosis in Iranian population. We conducted an association study and included 96 patients and 122 matched healthy individuals. We used single ARMS-PCR technique to simultaneously genotype fourteen polymorphisms in this survey. Among all fourteen polymorphisms that were examined, three polymorphisms were significantly different between case and control groups. The TNF -308A polymorphism showed significant increase in allele and genotype frequencies among patients compared to control individuals [-308A allele: 19.3 vs. 9.4%, GA genotype: 28.1 vs. 17.2%, AA genotype: 5.2 vs. 0.8%; Corrected P (Pc)<0.05], and the TLR4 variant allele and genotypes prevalence (D299G and T399I) were significantly higher among patients compared to controls [DG genotype: 14.6 vs. 5.7%, Pc<0.05 and I399 allele: 4.2 vs. 0.8%, TI genotype: 8.3 vs. 1.6%; Pc<0.05], respectively. In conclusion, our data suggest that TLR4 (D299G and T399I) and TNF (-308G/A) genetic polymorphisms may influence the risk of developing tuberculosis after exposure to Mycobacterium.

Cytokine and Adipokine Levels in Patients with Premalignant Oral Lesions or in Patients with Oral Cancer Who Did or Did Not Receive 1α,25-Dihydroxyvitamin D3 Treatment upon Cancer Diagnosis

Differences in levels of inflammation-modulating cytokines and adipokines in patients with premalignant oral lesions versus in patients that develop squamous cell carcinoma of the head and neck (HNSCC) were assessed. Also assessed was the impact of treating HNSCC patients with the immune regulatory mediator, 1α,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃], on modulators of inflammation. Compared to healthy controls, patients with premalignant oral lesions had increases in their systemic levels of the inflammatory cytokines IL-6 and IL-17, and increases in the adipokine, leptin. However, levels of these pro-inflammatory cytokines and adipokine were reduced in patients with HNSCC. Treatment of HNSCC patients with 1,25(OH)₂D₃ increased levels of each of the measured immune mediators. Levels of the anti-inflammatory adipokine, adiponectin, were shifted inversely with the levels of the pro-inflammatory cytokines and with leptin. These studies demonstrate heightened immune reactivity in patients with premalignant lesions, which wanes in patients with HNSCC, but which is restored by treatment with 1,25(OH)₂D₃.

Vitamin D Deficiency and Survival in Children after Hematopoietic Stem Cell Transplant

Vitamin D has endocrine function as a key regulator of calcium absorption and bone homeostasis and also has intracrine function as an immunomodulator. Vitamin D deficiency before hematopoietic stem cell transplantation (HSCT) has been variably associated with higher risks of graft-versus-host disease (GVHD) and mortality. Children are at particular risk of growth impairment and bony abnormalities in the face of prolonged deficiency. There are few longitudinal studies of vitamin D deficient children receiving HSCT, and the prevalence and consequences of vitamin D deficiency 100 days after transplant has been poorly studied. Serum samples from 134 consecutive HSCT patients prospectively enrolled into an HSCT sample repository were tested for 25-hydroxy (25 OH) vitamin D levels before starting HSCT (baseline) and at 100 days after transplantation. Ninety-four of 134 patients (70%) had a vitamin D level < 30 ng/mL before HSCT, despite supplemental therapy in 16% of subjects. Post-transplant samples were available in 129 patients who survived to day 100 post-transplant. Vitamin D deficiency persisted in 66 of 87 patients (76%) who were already deficient before HSCT. Moreover, 24 patients with normal vitamin D levels before HSCT were vitamin D deficient by day 100. Overall, 68% of patients were vitamin D deficient (<30 ng/mL) at day 100, and one third of these cases had severe vitamin D deficiency (<20 ng/mL). Low vitamin D levels before HSCT were not associated with subsequent acute or chronic GVHD, contrary to some prior reports. However, severe vitamin D deficiency (<20 ng/mL) at 100 days post-HSCT was associated with decreased overall survival after transplantation (P = .044, 1-year rate of overall survival: 70% versus 84.1%). We conclude that all pediatric transplant recipients should be screened for vitamin D deficiency before HSCT and at day 100 post-transplant and that aggressive supplementation is needed to maintain sufficient levels.

VITAL-Bone Health: rationale and design of two ancillary studies evaluating the effects of vitamin D and/or omega-3 fatty acid supplements on incident fractures and bone health outcomes in the VITamin D and OmegA-3 TriaL (VITAL)

RATIONALE

Although vitamin D is widely used to promote skeletal health, definitive data on benefits and risks of supplemental vitamin D alone on bone are lacking. Results from large, randomized controlled trials in the general population are sparse. Data on the effects of supplemental omega-3 fatty acids (FAs) on bone are also limited.

DESIGN

The VITamin D and OmegA-3 TriaL (VITAL) is a double-blind, placebo-controlled trial assessing the role of vitamin D3 (2000 IU/d) and omega-3 FA (1g/d) supplements in reducing risks of cancer and cardiovascular disease among U.S. men aged ≥50 and women aged ≥55. To comprehensively test effects of supplemental vitamin D and/or omega-3 FAs on skeletal health, the VITAL: Effects on Fractures ancillary study is determining the effects of these supplements on incident fractures among 25,875 participants enrolled in the parent trial. Study investigators adjudicate fractures through a detailed review of medical records and radiological images (hip and femur). In a complementary ancillary, VITAL: Effects on Structure and Architecture is determining the effects of supplemental vitamin D and/or omega-3 FAs on bone with detailed phenotyping during in-person visits. Comprehensive assessments of bone density, turnover, structure/architecture, body composition, and physical performance are being performed at baseline and 2 years post-randomization.

CONCLUSION

Results from these studies will clarify the relationship between supplemental vitamin D and/or omega-3 FAs on bone health outcomes, and inform clinical care and public health guidelines on the use of supplemental vitamin D for the primary prevention of fractures in women and men.

Bimodal Influence of Vitamin D in Host Response to Systemic Candida Infection-Vitamin D Dose Matters

Vitamin D level is linked to susceptibility to infections, but its relevance in candidemia is unknown. We aimed to investigate the in vivo sequelae of vitamin D3 supplementation in systemic Candida infection. Implicating the role of vitamin D in Candida infections, we showed that candidemic patients had significantly lower 25-OHD concentrations. Candida-infected mice treated with low-dose 1,25(OH)2D3 had reduced fungal burden and better survival relative to untreated mice. Conversely, higher 1,25(OH)2D3 doses led to poor outcomes. Mechanistically, low-dose 1,25(OH)2D3 induced proinflammatory immune responses. This was mediated through suppression of SOCS3 and induction of vitamin D receptor binding with the vitamin D-response elements in the promoter of the gene encoding interferon γ. These beneficial effects were negated with higher vitamin D3 doses. While the antiinflammatory effects of vitamin D3 are well described, we found that, conversely, lower doses conferred proinflammatory benefits in Candida infection. Our study highlights caution against extreme deviations of vitamin D levels during infections.

Cloning of a functional 25-hydroxyvitamin D-1α-hydroxylase in zebrafish (Danio rerio)

Activation of precursor 25-hydroxyvitamin D3 (25D) to hormonal 1,25-dihydroxyvitamin D3 (1,25D) is a pivotal step in vitamin D physiology, catalysed by the enzyme 25-hydroxyvitamin D-1α-hydroxylase (1α-hydroxylase). To establish new models for assessing the physiological importance of the 1α-hydroxylase-25D-axis, we used Danio rerio (zebrafish) to characterize expression and biological activity of the gene for 1α-hydroxylase (cyp27b1). Treatment of day 5 zebrafish larvae with inactive 25D (5-150 nM) or active 1,25D (0.1-10 nM) induced dose responsive expression (15-95-fold) of the vitamin D-target gene cyp24a1 relative to larvae treated with vehicle, suggesting the presence of Cyp27b1 activity. A full-length zebrafish cyp27b1 cDNA was then generated using RACE and RT-PCR methods. Sequencing of the resulting clone revealed an open reading frame encoding a protein of 505 amino acids with 54% identity to human CYP27B1. Transfection of a cyp27b1 expression vector into HKC-8, a human kidney proximal tubular epithelial cell line, enhanced intracrine metabolism of 25D to 1,25D resulting in greater than twofold induction of CYP24A1 mRNA expression and a 25-fold increase in 1,25D production compared to empty vector. These data indicate that we have cloned a functional zebrafish CYP27B1, representing a phylogenetically distant branch from mammals of this key enzyme in vitamin D metabolism. Further analysis of cyp27b1 expression and activity in zebrafish may provide new perspectives on the biological importance of 25D metabolism.

1α,25-dihydroxyvitamin D3 in combination with transforming growth factor-β increases the frequency of Foxp3⁺ regulatory T cells through preferential expansion and usage of interleukin-2

A high prevalence of vitamin D insufficiency and deficiency exists worldwide, which is associated with an increased incidence and severity of a range of immune-mediated diseases. This has resulted in considerable interest in the immunodulatory functions of vitamin D. The active form of vitamin D, 1α,25-dihydroxyvitamin D3 [1,25(OH)₂D3], has been shown to increase the frequency of Foxp3⁺ CD4⁺ T regulatory (Treg) cells when present at high concentrations or under strong T-cell stimulation in culture. Supporting evidence exists in vivo for a positive association between serum 25(OH)D and Foxp3⁺ Treg cell numbers in humans. The aim of this work was to identify the cytokine milieu required in vitro to promote Foxp3⁺ Treg cells in cultures containing 1,25(OH)₂D3 at more moderate concentrations (10⁻⁷ m). Stimulation of human CD4⁺ T cells with a combination of 1,25(OH)₂D3 and transforming growth factor-β (TGF-β) greatly increased the frequency of Foxp3⁺ Treg cells, which is proposed to result from the preferential expansion of Foxp3⁺ Treg cells, as compared with the Foxp3⁻ effector T cells, in culture. The differential effect on proliferation may result from enhanced availability and usage of interleukin-2 by the Foxp3⁺ Treg cells compared with Foxp3⁻ effector T cells. In summary, modulation of the cytokine environment to one high in TGF-β in the presence of 1,25(OH)₂D3 (10⁻⁷ m) significantly increased Foxp3⁺ Treg cell frequency. These data provide additional evidence for the important immunomodulatory properties of 1,25(OH)₂D3 that exist and may help to control inflammatory diseases.

Insufficient autumn vitamin D intake and low vitamin D status in 7-year-old Icelandic children

OBJECTIVE

The aim was to investigate autumn vitamin D intake and status in 7-year-old Icelanders, fitting BMI and cardiorespiratory fitness as predictors.

DESIGN

Three-day food records and fasting blood samples were collected evenly from September to November, and cardiorespiratory fitness was measured with an ergometer bike. Food and nutrient intakes were calculated, and serum 25-hydroxyvitamin D (s-25(OH)D) and serum parathyroid hormone were analysed. Suboptimal vitamin D status was defined s-25(OH)D <50 nmol/l, and deficient status as s-25(OH)D <25 nmol/l.

SETTING

School-based study in Reykjavik, Iceland in 2006.

SUBJECTS

Of the 7-year-olds studied (n 265), 165 returned valid intake information (62 %), 158 gave blood samples (60 %) and 120 gave both (45 %).

RESULTS

Recommended vitamin D intake (10 μg/d) was reached by 22·4 % of the children and 65·2 % had s-25(OH)D <50 nmol/l. Median s-25(OH)D was higher for children taking vitamin D supplements (49·2 nmol/l v. 43·2 nmol/l, respectively; P < 0·0 0 1). Median s-25(OH)D was lower in November (36·7 nmol/l) than in September (59·9 nmol/l; P < 0·001). The regression model showed that week of autumn accounted for 18·9 % of the variance in s-25(OH)D (P < 0·001), vitamin D intake 5·2 % (P < 0·004) and cardiorespiratory fitness 4·6 % (P < 0·005).

CONCLUSIONS

A minority of children followed the vitamin D recommendations and 65 % had suboptimal vitamin D status during the autumn. Week of autumn was more strongly associated with vitamin D status than diet or cardiorespiratory fitness, which associated with vitamin D status to a similar extent. These results demonstrate the importance of sunlight exposure during summer to prevent suboptimal vitamin D status in young schoolchildren during autumn in northern countries. An increased effort is needed for enabling adherence to the vitamin D recommendations and increasing outdoor activities for sunlight exposure.

Immune, metabolic and epidemiological aspects of vitamin D in chronic kidney disease and transplant patients

Chronic kidney disease strongly impacts on mineral and bone metabolism. Despite numerous medications, the biological targets recommended by international guidelines are often unmet. Among the treatment armamentarium, native or nutritional vitamin D (25OHD3) has been rediscovered in the early 2000s, and its general and specific actions further studied. Effects on bone, immunity, infection prevention, muscle function and phosphocalcic metabolism have been reviewed. Assessment of nutritional vitamin D status showed very low serum 25OHD3 levels and increase in nutritional vitamin D prescription led to improvement in these levels. However, about 45% of adult CKD patients still have insufficient serum 25OHD3 levels. Epidemiological studies should be enforced to describe further the mineral and bone disease management in CKD.

Re-evaluating the role of vitamin D in the periodontium

The importance of vitamin D in maintaining skeletal health via the regulation of calcium has long been recognized as a critical function of this secosteroid. An abundance of literature shows an association between oral bone mineral density and some measure of systemic osteoporosis and suggests that osteoporosis/low bone mass may be a risk factor for periodontal disease. Recently, nonskeletal functions of vitamin D have gained notoriety for several reasons. Many cells that are not associated with calcium homeostasis have been demonstrated to possess membrane receptors for vitamin D. These include activated T and B lymphocytes, and skin, placenta, pancreas, prostate and colon cancer cells. In addition, vitamin D "insufficiency" is a worldwide epidemic and epidemiologic evidence has linked this condition to multiple chronic health problems, including cardiovascular and autoimmune diseases, hypertension and a variety of cancers. Interestingly, there is mounting evidence connecting diminished serum levels of vitamin D with increased gingival inflammation and supporting the concept of "continual vitamin D sufficiency" in maintaining periodontal health. The ability of vitamin D to regulate both the innate and the adaptive components of the host response may play an important role in this process. This review will examine the skeletal and nonskeletal functions of vitamin D, and explore its potential role in protecting the periodontium as well as in regulating periodontal wound healing.

Variations in the vitamin D-binding protein (DBP) gene are related to lower 25-hydroxyvitamin D levels in healthy girls: a cross-sectional study

BACKGROUND/AIMS

Vitamin D deficiency has been recognized as a worldwide epidemic affecting several pediatric and adolescent populations. We determined the genotype and haplotype distribution of the rs4588 and rs7041 polymorphisms of the GC gene encoding vitamin D-binding protein (DBP) and investigated the associations between these gene variants and their haplotypes with 25-hydroxyvitamin D [25(OH)D] levels in girls from South Brazil.

METHODS

Cross-sectional study including 198 apparently healthy girls aged 10-18 years. Plasma levels of 25(OH)D were assessed by radioimmunoassay. Participants were genotyped for rs4588 and rs7041 by real-time PCR, with allelic discrimination assays.

RESULTS

Mean chronological age and BMI percentile were 13.17 ± 1.74 years and 57.81 ± 29.03, respectively. Sufficient circulating 25(OH)D levels (≥30 ng/ml) were found in 9.1% of the overall group, insufficient levels (20-29.9 ng/ml) in 59.6%, and deficient levels (<20 ng/ml) in 31.3%. The AA genotype of rs4588, TT genotype of rs7041 and CT-AT/AT-AT (GC 1f-2/2-2) diplotypes were significantly associated with lower 25(OH)D levels, even after adjustment for age and season at the time of blood collection.

CONCLUSIONS

The GC gene genotype may be related to the susceptibility to low 25(OH)D levels in female children and adolescents.

Vitamin D and Crohn's disease in the adult patient: a review

Crohn's disease (CD) is characterized as a chronic immune-mediated inflammatory disorder of the gastrointestinal tract. Current consensus surrounding the cause of the disease suggests a complex interplay between genetic susceptibility, the intestinal microbiome and environmental factors, leading to the aberrant Th1 and Th17 immune cell mediated response. Vitamin D deficiency is common in CD patients, and long-standing deficiency has been associated with reduced bone mineral density (BMD). Accumulating evidence now suggests that in addition to maintaining skeletal integrity, vitamin D also plays an integral role in regulating the general immune response, a function employed via its genomic actions on the vitamin D receptor (VDR). The VDR is expressed in all immune cells and both directly and indirectly targeted by the bioactive form of vitamin D, 1,25-Dihydroxyvitamin D (1,25[OH]2D). Impaired regulation or deficiency of the vitamin has been linked to the promotion of self-reactive T cell development, loss of immune tolerance to self-structures, and experimental colitis in animal models, whereas the subsequent administration of the vitamin in these models resulted in the improvement of immune-mediated symptoms. In addition, low vitamin D has been associated with disease activity in CD patients, and supplementation appears to be beneficial in improving clinical scores and reducing inflammation. Therefore, the primary aims of this article were to review the molecular evidence supporting the immunoregulatory roles of vitamin D and its supplementation in the CD patient, based on existing literature. The physiological processes, accepted serum concentration values, and its well-recognized role in bone health were also summarized.

Immune regulatory activity of vitamin d3 in head and neck cancer

While vitamin D exhibits a multitude of cellular effects that can impact on cancer development and progression, this review focuses on its immune modulatory effects. These immune modulatory effects can be both direct and indirect. Compared to other cancer types, head and neck squamous cell carcinomas (HNSCC) have received less attention, but are a fascination immunologically because of the profound extent to which they inhibit immune defenses. This review describes the mechanisms of some of these immune inhibitory processes and how vitamin D can help overcome aspects of this immune suppression.

Circulating 25-hydroxyvitamin D, vitamin D-binding protein and risk of prostate cancer

We recently reported a significant positive association between 25-hydroxyvitamin D [25(OH)D], the accepted biomarker of vitamin D status, and prostate cancer risk. To further elucidate this association, we examined the influence of vitamin D-binding protein (DBP), the primary transporter of vitamin D compounds in the circulation. Prediagnostic serum concentrations of DBP were assayed for 950 cases and 964 matched controls with existing 25(OH)D measurements within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of Finnish men. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), and statistical tests were two sided. Serum DBP modified the association between serum 25(OH)D and prostate cancer, with higher risk for elevated 25(OH)D levels observed primarily among men having DBP concentrations above the median (OR = 1.81, 95% CI: 1.18-2.79 for highest vs. lowest quintile, p-trend = 0.001) compared to those with DBP below the median (OR = 1.22, 95% CI: 0.81-1.84, p-trend 0.97; p-interaction = 0.04). Serum DBP was not associated with prostate cancer risk overall (OR = 0.96, 95% CI: 0.70-1.33 for highest vs. lowest quintile); however, high serum DBP was associated with significantly decreased risk of prostate cancer in men with lower ( Collapse

Key Words

• vitamin d binding protein
• 25-hydroxyvitamin d
• prostate cancer
• serum biomarkers
• prospective study

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MESH Headings

• Adult
• Aged
• Humans
• Male
• Middle Aged
• Odds Ratio
• Prostatic Neoplasms/blood
• Prostatic Neoplasms/epidemiology
• Risk
• Vitamin D/analogs & derivatives
• Vitamin D/blood
• Vitamin D-Binding Protein/blood

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Grants

• Z01 CP010195 Intramural NIH HHS
• N01-RC-45035 CCR NIH HHS
• ZIA CP010195 Intramural NIH HHS
• HHSN261200800001C NCI NIH HHS
• ZIA CP010195-06 Intramural NIH HHS
• HHSN261201000006C NCI NIH HHS
• N01RC37004 CCR NIH HHS
• N01 CN045165 NCI NIH HHS
• HHSN261200800001E NCI NIH HHS

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Affiliation(s)

Stephanie J. Weinstein Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, 20892
Alison M. Mondul Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, 20892
William Kopp Clinical Support Laboratory, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702
Helen Rager Clinical Support Laboratory, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702
Jarmo Virtamo Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland
Demetrius Albanes Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, 20892

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Beyond mineral metabolism, is there an interplay between FGF23 and vitamin D in innate immunity?

Fibroblast growth factor 23 (FGF23) is an "endocrine" FGF acting in the kidney as a phosphaturic hormone and a suppressor of active vitamin D, through an inhibition of the 1α hydroxylase and a stimulation of the 24 hydroxylase. Beyond its well-known effects on the bone/kidney/parathyroid axis and its deregulation during chronic kidney disease (CKD), recent evidence has revealed its direct systemic effects on cardiovascular health. In the meantime, studies have highlighted the health implications for vitamin D inside and outside CKD that also extend beyond its classical actions on mineral homeostasis and bone metabolism: vitamin D has indeed been shown to exert pluripotent non-classical effects as a modulator of immune function in monocytes, mainly through the stimulation of the antimicrobial cathelicidin. The aim of this review is to provide new insights on the interplay between FGF23 and vitamin D in innate immunity in the context of CKD.

Vitamin D in exercise: physiologic and analytical concerns

Despite a wide number of studies performed on the general population, little is known about the Vitamin D status of athletes. A particular influence of many factors, including skin pigmentation, early- or late-day training, indoor training, geographic location and extensive sunscreen use, has been observed in this specific population. The need of supplementation with Vitamin D in athletes is not defined or, when supplementation is needed, even the optimal amount of Vitamin D to be used is not specified. The periodic measurement of Vitamin D is the only procedure capable to define athletes' status. Although various methods for the measurement of Vitamin D are routinely used, they often give discordant and poorly reproducible results; thus, it is necessary to standardize the various methods, in order to have comparable results. In conclusion, current available data indicate both that little is known about the Vitamin D status of athletes and that is still unclear if supplementation could be desirable. Finally, it must be pointed out that all the papers about Vitamin D status should indicate in detail the method used for really allowing a correct interpretation of data.

Identification of urinary Gc-globulin as a novel biomarker for bladder cancer by two-dimensional fluorescent differential gel electrophoresis (2D-DIGE)

Improving the early detection rate and surveillance of bladder cancer remains a great challenge in medicine. Here, we identified sixteen proteins including Gc-globulin (GC) in urine from bladder cancer patients and normal controls by two-dimensional fluorescent differential gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Bioinformatics analyses indicated GC played important roles in the regulation of growth, apoptosis, death and epidermal growth factor receptor activity. The GC expression patterns in urine or tissue from cases and controls were further quantified by western blotting, immunohistochemical staining and enzyme-linked immunosorbent assay (ELISA). ELISA quantification by correcting for creatinine expression showed GC-Cr was significantly increased in bladder cancer patients than in benign bladder damages cases and normal controls (1013.70±851.25 versus 99.34±55.87, 105.32±47.81 ng/mg, respectively). Receiver operating characteristic (ROC) analysis suggested that at 161.086 ng/mg urinary GC, bladder cancer could be detected with 92.31% sensitivity and 83.02% specificity, and 1407.481 ng/mg with 82.61% sensitivity and 88.24% specificity could be used for the detection of infiltrating urothelial carcinoma of bladder cancer. Taken together, we identified GC as a potential novel urinary biomarker for the early detection and surveillance of bladder cancer.

Effect of activated vitamin D on glucoparameters in HCV seropositive and seronegative patients on chronic hemodialysis

INTRODUCTION

Many studies support the role of vitamin D in the pathogenesis of both types of diabetes. Pancreatic tissues express the vitamin D receptor (VDR) and vitamin D-binding protein; some allelic variations in genes involved in vitamin D metabolism and VDR are associated with glucose intolerance, defective insulin secretion, and sensitivity. Epidemiological links have been established between type 2 diabetes mellitus (DM) and hepatitis C virus (HCV) infection.

AIM

To explore the possible therapeutic potential of pharmacologic doses of 1-α-hydroxy vitamin D therapy in improving pancreatic β-cell function in HCV seropositive hemodialysis (HD) patients.

PATIENTS AND METHODS

Twenty HCV seropositive HD patients and 20 HCV seronegative patients as control group were randomly selected from HD units. 1-α-Hydroxy vitamin D therapy was administrated in the dose ranged from 0.25 to 0.5 μg/day for 3 months. Corrected total serum calcium, phosphorus, intact parathyroid hormone (iPTH), 25-hydroxy vitamin D [25(OH) vitamin D], 1,25-dihydroxy vitamin D, and glucoparameters [fasting blood glucose, glycohemoglobin test (HbA1c%), homeostatic model assessment (HOMA)-insulin resistance, and HOMA-β-cell function% (B%)] were measured under basal conditions and after 3 months of therapy.

RESULTS

There was highly significant improvement in the concentrations of fetal bovine serum (FBS), serum insulin, HbA1c%, 25(OH) vitamin D, and HOMA-β-cell function in HCV seropositive and HCV seronegative groups after oral 1-alphacalcidiol therapy (p < 0.001). Positive correlation exists between the percentage increase in serum insulin and that in HOMA-β-cell function versus 25(OH) vitamin D (p < 0.021 and p < 0.027, respectively) in HCV negative group.

CONCLUSION

1-α-Hydroxy vitamin D oral therapy may improve glycemic control in HCV seropositive and HCV seronegative HD patients.

Review article: vitamin D and inflammatory bowel disease--established concepts and future directions

BACKGROUND

Understanding of the role of vitamin D in health and disease has increased markedly in the past decade, with its involvement extending well beyond traditional roles in calcium and phosphate homeostasis and musculoskeletal health. This conceptual expansion has been underpinned by identification and exploration of components of this axis including vitamin D-binding protein, key enzymes and receptors in multiple cell types, and a greater recognition of nonclassical autocrine and paracrine effects. Its influence in IBD remains uncertain.

AIM

To review the role of vitamin D in bone health, immune regulation and cancer prevention in IBD, and to outline practical issues and limitations of its use.

METHODS

An extensive online literature review including PubMed and Medline.

RESULTS

In patients with IBD, the vitamin D axis provides an important and often underutilised pathway to preserving bone health. Furthermore, an exciting body of clinical and basic science research demonstrates that these pathways may have an integral part to play in regulation of the immune response in IBD, through effects on the intestinal barrier, antigen presenting cells and adaptive T cells. The possibility of chemoprevention requires further study. The optimal target level of 25-hydroxy vitamin D in patients with IBD is currently uncertain, as is the best therapeutic modality.

CONCLUSIONS

Study of vitamin D pathways may result in the development of relatively inexpensive therapeutic options to optimise patient outcomes. Further prospective clinical research is required to address efficacy and long-term safety.

Vitamin d and cardiovascular disease

OPINION STATEMENT

Vitamin D has received widespread attention for its potential role in preventing cardiovascular disease (CVD) and type 2 diabetes mellitus. Several epidemiological studies have suggested that individuals with low blood levels of vitamin D have increased risks of heart disease, stroke, hypertension, and diabetes. Yet, the revised 2011 Institute of Medicine report for intake of calcium and vitamin D, which was guided by skeletal health alone, concluded that the evidence that vitamin D prevents CVD, diabetes, or other cardiometabolic outcomes was inconsistent and inconclusive and did not meet criteria for establishing a cause and effect relationship [1•, 2]. This finding was consistent with an earlier systematic review conducted by the Agency for Healthcare Research and Quality (AHRQ) in 2009 [3•]. Ongoing clinical trials seek to address the effects of vitamin D supplementation on CVD and other nonskeletal outcomes.

Melatonin: an overlooked factor in schizophrenia and in the inhibition of anti-psychotic side effects

This paper reviews melatonin as an overlooked factor in the developmental etiology and maintenance of schizophrenia; the neuroimmune and oxidative pathophysiology of schizophrenia; specific symptoms in schizophrenia, including sleep disturbance; circadian rhythms; and side effects of antipsychotics, including tardive dyskinesia and metabolic syndrome. Electronic databases, i.e. PUBMED, Scopus and Google Scholar were used as sources for this review using keywords: schizophrenia, psychosis, tardive dyskinesia, antipsychotics, metabolic syndrome, drug side effects and melatonin. Articles were selected on the basis of relevance to the etiology, course and treatment of schizophrenia. Melatonin levels and melatonin circadian rhythm are significantly decreased in schizophrenic patients. The adjunctive use of melatonin in schizophrenia may augment the efficacy of antipsychotics through its anti-inflammatory and antioxidative effects. Further, melatonin would be expected to improve sleep disorders in schizophrenia and side effects of anti-psychotics, such as tardive dyskinesia, metaboilic syndrome and hypertension. It is proposed that melatonin also impacts on the tryptophan catabolic pathway via its effect on stress response and cortisol secretion, thereby impacting on cortex associated cognition, amygdala associated affect and striatal motivational processing. The secretion of melatonin is decreased in schizophrenia, contributing to its etiology, pathophysiology and management. Melatonin is likely to have impacts on the metabolic side effects of anti-psychotics that contribute to subsequent decreases in life-expectancy.

Vitamin D: an essential component for skeletal health

Vitamin D deficiency is increasing worldwide. Ultraviolet rays are supposed to provide humans over 80% of our vitamin D requirement; the rest is received through diet and supplements. In addition to enhancing calcium absorption from the intestine and mineralization of the osteoid tissue, vitamin D has many other physiological effects, including neuromodulation, improving muscle strength and coordination, insulin release, immunity and prevention of infections, and curtailing cancer. Whether the increased incidence of vitamin D deficiency is related to increased incidences of nonskeletal disorders remains to be determined. Serum levels of 25-hydroxyvitamin [25(OH)D] above 30 ng/mL indicate vitamin D sufficiency. An additional 1,000 IU of vitamin D/day is sufficient for most lighter-skinned individuals, whereas an extra 2,000 IU/day is needed by the elderly and dark-skinned individuals to maintain normal 25(OH)D levels. Additional research is needed to clarify the relationship between vitamin D and the nonskeletal systems, nonclassic functions, and targets of vitamin D.

Immunological modulation by 1α,25-dihydroxyvitamin D3 in patients with squamous cell carcinoma of the head and neck

Prior studies showing that treatment of head and neck squamous cell carcinoma (HNSCC) patients with 1α,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] stimulated intratumoral immune infiltration were extended to analysis of cytokine profiles in the periphery and in oral tissues. Most prominent was the disparity between cytokine levels in plasma and in either pathologically normal oral tissue or HNSCC tissue from patients that were untreated or treated with 1,25(OH)(2)D(3). Levels of IL-6 and IL-10, but not IL-2, IFN-γ or TNF-α, tended to be increased in the plasma of HNSCC patients and 1,25(OH)(2)D(3) further increased plasma levels of all of these cytokines. While these cytokines tended to be increased in HNSCC tissue, 1,25(OH)(2)D(3) resulted in variable cytokine responses that showed a general tendency toward further increased levels. Levels of IL-8 and VEGF were increased in plasma and tissue of untreated HNSCC patients, and were further increased in plasma, but not in tissues, of patients treated with 1,25(OH)(2)D(3). Levels of IL-1α and IL-1β were similar in plasma of controls and HNSCC patients, but were increased in HNSCC tissues. In contrast to that seen in plasma where 1,25(OH)(2)D(3) increased levels of IL-1α and IL-1β, this was not seen in tissue following 1,25(OH)(2)D(3) treatment. These results show a discordant relationship between systemic and intratumoral cytokine profiles and suggest a tendency of 1,25(OH)(2)D(3)to increase a multitude of cytokines within tumor tissue.

Impact of circulating vitamin D binding protein levels on the association between 25-hydroxyvitamin D and pancreatic cancer risk: a nested case-control study

High concentrations of circulating 25-hydroxyvitamin D [25(OH)D] have been associated with elevated pancreatic cancer risk. As this is contrary to an expected inverse association between vitamin D status and cancer, we examined whether vitamin D binding protein (DBP), the primary carrier of vitamin D compounds in circulation, plays a role in this relationship. Prediagnostic serum DBP and 25(OH)D were studied in relation to risk of pancreatic cancer in a nested case-control study of 234 cases and 234 controls in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of Finnish men. ORs and 95% CIs were estimated using logistic regression, and statistical tests were two-sided. We found that DBP and 25(OH)D were correlated (r = 0.27, P < 0.0001), and DBP was inversely associated with pancreatic cancer risk (OR = 0.66, 95% CI = 0.39-1.12, for the highest vs. lowest quartile; P(trend) = 0.02). Importantly, this association seemed to have a threshold between quartiles 2 to 4 and quartile 1, and was primarily evident among men with concurrent high 25(OH)D concentrations (OR = 0.33, 95% CI = 0.16-0.70 for highest vs. lowest quartile; P(trend) = 0.002), with no association in men with lower serum 25(OH)D (OR = 1.28, 95% CI = 0.62-2.61 for highest vs. lowest quartile, P(trend) 0.63, P(interaction) = 0.01). Men with higher 25(OH)D concentrations and serum DBP below the median showed greatly elevated risk of pancreatic cancer (OR = 5.01, 95% CI 2.33-10.78, for highest vs. lowest quartile; P(trend) < 0.0001), while risk was weakly inversely associated with serum 25(OH)D when DBP concentrations were higher (P(interaction) = 0.001). Taken together, our findings indicate that higher DBP concentrations may sequester more 25(OH)D and reduce free 25(OH)D bioavailability. Simultaneous examination of DBP and 25(OH)D may be important in determining the association of vitamin D with cancer risk.

Vitamin D in the new millennium

The incidence of vitamin D deficiency is rising worldwide, yet in the vast majority of patients, the condition remains undiagnosed and untreated. Current evidence overwhelmingly indicates that supplemental doses greater than 800 IU/day have beneficial effects on the musculoskeletal system, improving skeletal homeostasis, thus leading to fewer falls and fractures. Evidence is also accumulating on the beneficial effects of vitamin D on extraskeletal systems, such as improving immune health, autoimmune disorders, cancer, neuromodulation, diabetes, and metabolic syndrome. The cause-effect relationship of vitamin D deficiency with increasing incidences of nonskeletal disorders is being investigated. Published reports support the definition of sufficiency, serum levels of 25-hydroxyvitamin D [25(OH)D] greater than 30 ng/mL (75 nmol/L). To achieve this, most people need vitamin D supplementation ranging from 600 to 2000 IU/day; consumption up to of 5000 international units (IU) per day of vitamin D is reported as safe. Although light-skinned individuals need 1000 IU/day of vitamin D, elderly and dark-skinned individuals are likely to need approximately 2000 IU/day to maintain serum 25(OH)D levels greater than 30 ng/mL. Other vulnerable patients, such as the obese, those who have undergone bariatric surgery, and those with gastrointestinal malabsorption syndromes, may require higher doses of vitamin D to maintain normal serum levels and be healthy.

Fatty liver is associated with recurrent bacterial infections independent of metabolic syndrome

BACKGROUND

Diabetes mellitus and obesity are important components of metabolic syndrome (MetS) which are associated with infections. MetS is frequent in nonalcoholic fatty liver disease (NAFLD).

AIMS

The objective of this study was to examine whether patients with NAFLD are at higher risk of recurrent bacterial infections (RBIs).

METHODS

Two-hundred and forty-seven from 296 hospitalized NAFLD patients were assessed over a three-year period for the occurrence of RBIs and were compared with 100 age and gender-matched patients without NAFLD, who were hospitalized over the same period because of a bacterial infection. An RBI was defined as: ≥2 episodes of bacterial infections per year for a period of three consecutive years. NAFLD was diagnosed by ultrasonography. Biomarkers of inflammation, the level of oxidative stress, insulin resistance, and serum vitamin D levels were measured.

RESULTS

NAFLD patients had significantly more RBIs than the patients without NAFLD (22% vs. 8%; P < 0.001). Univariate analysis showed that age, BMI, male waist circumference, serum 25(OH)D, triglycerides, serum malondialdehyde, and paraoxonase-1 are associated with RBIs in NAFLD patients. Multivariate analysis showed that NAFLD (odds ratio (OR) = 3.0, 95% confidence interval (CI) = 2.6-4.2, P < 0.001), serum 25(OH)D level <20 ng/mL (OR = 2.6; 95% CI 2.4-3.1, P = 0.01), obesity (BMI >30 kg/m(2) (OR = 2.2, 95% CI 1.8-2.9, P = 0.02) were associated with RBIs, irrespective of MetS.

CONCLUSIONS

NAFLD is associated with increased risk of RBIs irrespective of MetS. Vitamin D insufficiency is frequent in NAFLD and is associated with increased risk of RBIs.

Association of vitamin D binding protein (VDBP) polymorphisms and serum 25(OH)D concentrations in a sample of young Canadian adults of different ancestry

Variants of the vitamin D binding protein (VDBP) gene appear to be associated with levels of the main circulating vitamin D metabolite, 25-hydroxyvitamin D [(25(OH)D]. We examined the associations between the common variants of the VDBP (GC) gene and concentrations of 25(OH)D in a sample of young Canadian adults of East Asian, European and South Asian ancestry, taking into account the effect of vitamin D intake, skin pigmentation, sex, BMI, sun exposure and season. Three hundred and fifty-one (351) healthy young adults were genotyped for two non-synonymous single nucleotide polymorphisms (SNPs), T436K (rs4588) and D432E (rs7041), using a method that ascertains the GC diplotypes of each individual. After controlling for relevant predictor variables in multiple regression models, the number of GC-2 (436K) alleles was found to be associated with lower 25(OH)D concentrations in the East Asian sample at fall and winter visits. The number of GC-2 alleles also showed a significant negative association with fall 25(OH)D concentration in the European sample. No associations were noted between the number of GC-2 alleles and 25(OH)D in the South Asian sample at either season. Vitamin D intake was also significantly predictive of serum 25(OHD) concentrations, and similarly to what was observed for the GC polymorphisms, the relative strength of the association was influenced by ancestry and season.