A phase I/II dose-escalation trial of vitamin D3 and calcium in multiple sclerosis

The Use of 1α,25-Dihydroxyvitamin D₃ as an Anticancer Agent

The notion that vitamin D can influence the incidence of cancer arose from epidemiological studies. The major source of vitamin D in the organism is skin production upon exposure to ultra violet-B. The very first observation of an inverse correlation between exposure of individuals to the sun and the likelihood of cancer was reported as early as 1941. In 1980, Garland and Garland hypothesised, from findings from epidemiological studies of patients in the US with colon cancer, that vitamin D produced in response to sun exposure is protective against cancer as opposed to sunlight per se. Later studies revealed inverse correlations between sun exposure and the occurrence of prostate and breast cancers. These observations prompted laboratory investigation of whether or not vitamin D had an effect on cancer cells. Vitamin D is not active against cancer cells, but the most active metabolite 1α,25-dihydroxyvitamin D₃ (1,25D) has profound biological effects. Here, we review the anticancer action of 1,25D, clinical trials of 1,25D to date and the prospects of the future therapeutic use of new and low calcaemic analogues.

Emerging Concepts on the Gut Microbiome and Multiple Sclerosis

Microbiota of the human body perform fundamental tasks that contribute to normal development, health, and homeostasis and are intimately associated with numerous organ systems, including the gut. Microbes begin gut inhabitance immediately following birth and promote proper gut epithelial construction and function, metabolism and nutrition, and immune system development. Inappropriate immune recognition of self-tissue can lead to autoimmune disease, including conditions such as multiple sclerosis (MS), in which the immune system recognizes and attacks central nervous system tissue. Preclinical studies have demonstrated a requirement of gut microbiota for neuroinflammatory autoimmune disease in animal models, and a growing number of clinical investigations are finding associations between MS status and the composition of the gut microbiota. In this review, we examine current undertakings into better understanding the role of gut bacteria and their phages in MS development, review associations of the gut microbiota makeup and MS, and discuss potential mechanisms by which the gut microbiota may be manipulated for therapeutic benefit.

Association of seasonal serum 25-hydroxyvitamin D levels with disability and relapses in relapsing-remitting multiple sclerosis

BACKGROUND/OBJECTIVES

The aim of this study was to evaluate the association of serum 25-hydroxyvitamin D (25(OH)D) with disability and frequency of relapses in relapsing-remitting multiple sclerosis (MS) patients.

SUBJECTS/METHODS

The study included 184 patients with relapsing-remitting MS who were receiving immune-modulating drugs and no vitamin D supplementation. The concentration of 25(OH)D was measured in February and August 2014. The level of disability was assessed twice according to the Expanded Disability Status Scale (EDSS). The patients were divided into two groups: EDSS 0.0-2 and 2.5-4. The control group comprised 58 age- and sex-matched healthy subjects. The 25(OH)D levels were compared with the occurrence of relapses and the level of disability.

RESULTS

Mean serum 25(OH)D concentrations were significantly lower in winter in both MS patients and controls. Winter level of 25(OH)D was significantly lower in severe MS cases (EDSS 2.5-4.0) than in mild cases (EDSS 0.0-2.0) (P=0.022), and in the controls (P=0.008), especially in females (r=0.38, P=0.0015). Logistic regression analysis showed the winter serum 25(OH)D was significantly associated with MS (odds ratio 0.925; 95% confidence interval, 0.822-0.970). Serum 25(OH)D levels were significantly lower in MS patients with relapses than in those without relapses both in winter, and in summer.

CONCLUSIONS

Hypovitaminosis D was more prevalent during winter than summer, both in the sample group and the control, especially in female MS patients with higher levels of disability. Low vitamin D levels are associated with a more severe course of disease and an increased number of relapses.

Vitamin D and Diabetic Complications: True or False Prophet?

Vitamin D deficiency is now recognized as a condition of increasing prevalence worldwide. Vitamin D has an established role in calcium and bone metabolism; however, more recently associations with vitamin D deficiency and risk of developing diabetes, diabetes complications, and cardiovascular disease have all been acknowledged. The vitamin D receptor is ubiquitously expressed, and experimental, in vitro, and in vivo studies strongly suggest a role in regulating the transcription of multiple genes beyond calcium homeostasis. These include antiproliferative, immunomodulatory, angiogenic, inhibition of the renin-angiotensin-aldosterone system, and neurotrophic factor expression. Observational studies report a strong association between vitamin D deficiency and cardiovascular and metabolic disorders; however, there remains a paucity of large long-term randomized clinical trials showing a benefit with treatment. An increasing body of literature suggests a possible pathogenetic role of vitamin D in the long-term complications of diabetes and vitamin D deficiency may also exacerbate symptoms of painful diabetic peripheral neuropathy. It remains unknown if supplementation of vitamin D to normal or non-deficient levels alters pathogenetic processes related to diabetic microvascular complications. With the high prevalence of vitamin D deficiency in patients with diabetes and putative mechanisms linking vitamin D deficiency to diabetic complications, there is a compelling argument for undertaking large well-designed randomized controlled trials of vitamin D supplementation.

Illuminating vitamin D effects on B cells--the multiple sclerosis perspective

Vitamin D is associated with many immune-mediated disorders. In multiple sclerosis (MS) a poor vitamin D status is a major environmental factor associated with disease incidence and severity. The inflammation in MS is primarily T-cell-mediated, but increasing evidence points to an important role for B cells. This has paved the way for investigating vitamin D effects on B cells. In this review we elaborate on vitamin D interactions with antibody production, T-cell-stimulating capacity and regulatory B cells. Although in vitro plasma cell generation and expression of co-stimulatory molecules are inhibited and the function of regulatory B cells is promoted, this is not supported by in vivo data. We speculate that differences might be explained by the B-cell-Epstein-Barr virus interaction in MS, the exquisite role of germinal centres in B-cell biology, and/or in vivo interactions with other hormones and vitamins that interfere with the vitamin D pathways. Further research is warranted to illuminate this tube-versus-body paradox.

Non-linear contribution of serum vitamin D to symptomatic diabetic neuropathy: A case-control study

AIMS

Vitamin D deficiency has recently been speculated to be associated with increased risk of diabetes neuropathy (DN). The aim of this study was to evaluate the odds of symptomatic DN across serum vitamin D levels.

METHODS

All patients with DM were assessed using diabetic neuropathy symptoms and diabetic neuropathy examination score. Overall, 150 cases with DN and 600 controls were included. Serum 25-hydroxyvitamin D (25-OH-D) was measured to determine vitamin D status.

RESULTS

A non-linear association between 25-OH-D and suffering from symptomatic DN was observed which was extracted after stratifying the ORs across different serum 25-OH-D levels. When compared to individuals with 25-OH-D of 30-40 ng/mL, patients with deficient (<20 ng/mL) vitamin D levels had higher odds of having symptomatic DN (OR: 2.04, 95%CI: 0.99-4.02, P=0.054). Participants with vitamin D values of greater than 40 ng/mL were also more likely to exhibit symptomatic DN (fully adjusted OR: 4.29, 95%CI: 1.59-11.55).

CONCLUSIONS

We hypothesize a non-linear contribution of serum vitamin D to symptomatic DN occurrence, which emphasizes that administration of vitamin D should be monitored and evaluated more carefully, especially in patients with diabetes.

Environmental Factors and Their Regulation of Immunity in Multiple Sclerosis

In multiple sclerosis (MS), environmental factors and genetic traits cooperate in the induction of the chronic activation of immune cells to produce the brain pathology. Epidemiology has focused on different environmental risk factors but certainly virus infection, smoking, vitamin D levels, and sunlight exposure are the most relevant. What is certainly less clear is the way in which these external factors are able to induce and sustain the internal pathology process of the disease. Epigenetics has been recently focused on trying to shed light on this aspect. As a matter of fact epigenetic changes are highly sensitive to environmental factors that therefore may influence the susceptibility to the disease by acting through epigenetic modifications. In this chapter we discuss the most relevant environmental factors and how they may affect the immune response in MS. Finally, we discuss the possible role of the microbiota in inducing autoimmunity in MS.

Vitamin D as Supplemental Therapy for Pneumocystis Pneumonia

The combination of all-trans retinoic acid (ATRA) and primaquine (PMQ) has been shown to be effective for therapy of Pneumocystis pneumonia (PCP). Since a high concentration of ATRA has significant adverse effects, the possibility that vitamin D can be used to replace ATRA for PCP therapy was investigated. C57BL/6 mice were immunosuppressed by depleting CD4(+) cells and infected with Pneumocystis murina 1 week after initiation of immunosuppression. Three weeks after infection, the mice were treated orally for 3 weeks with vitamin D3 (VitD3) alone, PMQ alone, a combination of VitD3 and PMQ (VitD3-PMQ), or a combination of trimethoprim and sulfamethoxazole (TMP-SMX). Results showed that VitD3 (300 IU/kg/day) had a synergistic effect with PMQ (5 mg/kg/day) for therapy of PCP. Flow cytometric studies showed that this VitD3-PMQ combination recovered the CD11b(low) CD11c(high) alveolar macrophage population in mice with PCP as effectively as TMP-SMX. The VitD3-PMQ combination also reduced the massive infiltration of inflammatory cells into the lungs and the severity of lung damage. VitD3 was also shown to reduce the dose of TMP-SMX required for effective treatment of PCP. Taken together, results of this study suggest that a VitD3-PMQ combination can be used as an alternative therapy for PCP.

1,25-Dihydroxyvitamin D3-Conditioned CD11c+ Dendritic Cells are Effective Initiators of CNS Autoimmune Disease

Dendritic cells (DC) play a crucial role in regulating T cell activation. Due to their capacity to shape the immune response, tolerogenic DC have been used to treat autoimmune diseases. In this study, we examined whether 1,25 dihydroxyvitamin D3-conditioned bone marrow-derived DC (VitD-BMDC) were able to limit the development of autoimmune pathology in experimental autoimmune encephalomyelitis (EAE). We found that VitD-BMDC had lower expression of MHC class II and co-stimulatory molecules and were less effective at priming autoreactive T cells in vitro. Using our recently described BMDC-driven model of EAE, we demonstrated that VitD-BMDC had a significantly reduced ability to initiate EAE. We found that the impaired ability of VitD-BMDC to initiate EAE was not due to T cell tolerization. Instead, we discovered that the addition of 1,25(OH)2D3 to BMDC cultures resulted in a significant reduction in the proportion of CD11c+ cells. Purified CD11c+ VitD-BMDC were significantly less effective at priming T cells in vitro yet were similarly capable of initiating EAE as vehicle-treated CD11c+ BMDC. This study demonstrates that in vitro assays of DC function can be a poor predictor of in vivo behavior and that CD11c+ VitD-BMDC are highly effective initiators of an autopathogenic T cell response.

Vitamin D₃ and monomethyl fumarate enhance natural killer cell lysis of dendritic cells and ameliorate the clinical score in mice suffering from experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a CD4⁺ T cell mediated inflammatory demyelinating disease that is induced in mice by administration of peptides derived from myelin proteins. We developed EAE in SJL mice by administration of PLP_139–151 peptide. The effect of treating these mice with 1α,25-Dihydroxyvitamin D₃ (vitamin D₃), or with monomethyl fumarate (MMF) was then examined. We observed that both vitamin D₃ and MMF inhibited and/or prevented EAE in these mice. These findings were corroborated with isolating natural killer (NK) cells from vitamin D₃-treated or MMF-treated EAE mice that lysed immature or mature dendritic cells. The results support and extend other findings indicating that an important mechanism of action for drugs used to treat multiple sclerosis (MS) is to enhance NK cell lysis of dendritic cells.

Evidence for the Importance of Vitamin D Status in Neurologic Conditions

OPINION STATEMENT

Vitamin D status has been proposed as relevant to many neurological disorders. Data suggest that vitamin D may be important for the development of the nervous system, and it also plays a role in neuroimmunology and neuroprotection. Lower levels of circulating 25-hydroxyvitamin D have been linked with increased risk of multiple sclerosis (MS) and Alzheimer's disease (AD). While people with amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and stroke have lower vitamin D levels than those without the diseases, it is unclear if this is because hypovitaminosis D contributes to disease risk or is a consequence of immobility and other factors caused by the disease. Lower levels of vitamin D have been associated with worse prognosis in MS, PD, ALS, and stroke, while no longitudinal studies have been performed to evaluate such an association in AD. Small pilot trials have been performed to evaluate vitamin D supplementation for some of these diseases, but there have been no phase III studies to support vitamin D supplementation in these patient populations; further, ideal levels of 25-hydroxyvitamin D are not known. Thus, while some expert panels or individuals have suggested routine testing and supplementation for patients with these neurological conditions, it is our opinion that there are currently insufficient data to support high-dose vitamin D supplementation to specifically treat or prevent these conditions.

Update in vitamin D and multiple sclerosis

Multiple sclerosis (MS) is a common neurological disease, and its etiology remains unknown. In recent years, increasing attention has been paid to the possible association between MS and vitamin D deficiency. Here, we review the current literature between MS and vitamin D, showing clear evidence that vitamin D deficiency is a risk factor for MS despite the lack of direct evidence for the effects of vitamin D in MS progression.

Vitamin D supplementation and systemic inflammation in relapsing-remitting multiple sclerosis

Observational studies have suggested that vitamin D may reduce inflammation in relapsing-remitting multiple sclerosis (RRMS), but this has not been clearly confirmed in randomized controlled trials. To further explore the possible anti-inflammatory effects of vitamin D in RRMS, we examined the effect of high-dose oral vitamin D3 on eleven markers of systemic inflammation in 68 RRMS patients enrolled in a double-blinded randomized placebo-controlled trial of vitamin D3 supplementation (20,000 IU/week) (NCT00785473). Serum inflammation markers and 25-hydroxyvitamin D (25(OH)D) were measured at baseline and week 96, and no restrictions were set on additional standard immunomodulatory treatment for RRMS. The mean 25(OH)D level rose from 56 ± 29 to 123 ± 34 nmol/L among patients receiving vitamin D3 supplementation, whereas only a minor increase from 57 ± 22 to 63 ± 24 nmol/L was seen in the placebo group. However, no significant differences appeared between the vitamin D group and the placebo group for any of the inflammation markers. Patients on immunomodulatory therapy had significantly higher levels of interleukin-1 receptor antagonist and chemokine (C-X-C motif) ligand 16 than patients without immunomodulatory treatment, but there were no clear synergistic effects between immunomodulatory therapy and vitamin D3 supplementation on any of the inflammation markers. The rise in 25(OH)D levels after vitamin D3 supplementation was unaffected by immunomodulatory treatment. We conclude that in this study of RRMS patients, high-dose oral vitamin D3 supplementation prominently increased serum 25(OH)D levels without affecting markers of systemic inflammation, while a more anti-inflammatory phenotype was found among patients on immunomodulatory treatment.

Vitamin D and Risk of Multiple Sclerosis: A Mendelian Randomization Study

BACKGROUND

Observational studies have demonstrated an association between decreased vitamin D level and risk of multiple sclerosis (MS); however, it remains unclear whether this relationship is causal. We undertook a Mendelian randomization (MR) study to evaluate whether genetically lowered vitamin D level influences the risk of MS.

METHODS AND FINDINGS

We identified single nucleotide polymorphisms (SNPs) associated with 25-hydroxyvitamin D (25OHD) level from SUNLIGHT, the largest (n = 33,996) genome-wide association study to date for vitamin D. Four SNPs were genome-wide significant for 25OHD level (p-values ranging from 6 × 10-10 to 2 × 10-109), and all four SNPs lay in, or near, genes strongly implicated in separate mechanisms influencing 25OHD. We then ascertained their effect on 25OHD level in 2,347 participants from a population-based cohort, the Canadian Multicentre Osteoporosis Study, and tested the extent to which the 25OHD-decreasing alleles explained variation in 25OHD level. We found that the count of 25OHD-decreasing alleles across these four SNPs was strongly associated with lower 25OHD level (n = 2,347, F-test statistic = 49.7, p = 2.4 × 10-12). Next, we conducted an MR study to describe the effect of genetically lowered 25OHD on the odds of MS in the International Multiple Sclerosis Genetics Consortium study, the largest genetic association study to date for MS (including up to 14,498 cases and 24,091 healthy controls). Alleles were weighted by their relative effect on 25OHD level, and sensitivity analyses were performed to test MR assumptions. MR analyses found that each genetically determined one-standard-deviation decrease in log-transformed 25OHD level conferred a 2.0-fold increase in the odds of MS (95% CI: 1.7-2.5; p = 7.7 × 10-12; I2 = 63%, 95% CI: 0%-88%). This result persisted in sensitivity analyses excluding SNPs possibly influenced by population stratification or pleiotropy (odds ratio [OR] = 1.7, 95% CI: 1.3-2.2; p = 2.3 × 10-5; I2 = 47%, 95% CI: 0%-85%) and including only SNPs involved in 25OHD synthesis or metabolism (ORsynthesis = 2.1, 95% CI: 1.6-2.6, p = 1 × 10-9; ORmetabolism = 1.9, 95% CI: 1.3-2.7, p = 0.002). While these sensitivity analyses decreased the possibility that pleiotropy may have biased the results, residual pleiotropy is difficult to exclude entirely.

CONCLUSIONS

A genetically lowered 25OHD level is strongly associated with increased susceptibility to MS. Whether vitamin D sufficiency can delay, or prevent, MS onset merits further investigation in long-term randomized controlled trials.

Increased incidence of chronic GvHD and CMV disease in patients with vitamin D deficiency before allogeneic stem cell transplantation

Vitamin D has emerged as a central player in the immune system, with its deficiency being implicated in the pathogenesis of several autoimmune diseases, including chronic GvHD. This is a retrospective cohort analysis of 166 patients, who underwent allogeneic hematopoietic stem cell transplantation (HSCT) at the Karolinska University Hospital, evaluating GvHD, graft failure, infectious complications and survival after HSCT in relation to pre-transplantation vitamin D levels. Most of the patients were deficient in vitamin D before HSCT (median 42 nmol/L). In multivariate analysis, vitamin D level before HSCT was identified as a significant independent risk factor for development of cGvHD. The increased incidence of cGvHD was not coupled to better disease-free survival; instead there was a trend towards lower overall survival in the vitamin D-deficient patients. In addition, we found a significant correlation between vitamin D deficiency and incidence of CMV disease, with no case of CMV disease occurring in patients with sufficient levels of vitamin D before HSCT. Our results support a role of vitamin D in immune tolerance following HSCT. These findings could be highly relevant for the care of HSCT patients, and prospective, randomized studies on the effect of vitamin D supplementation are therefore needed.

Investigation of Bone Health Subsequent to Vitamin D Supplementation in Children Following Burn Injury

BACKGROUND

The effect of supplemental vitamin D on fracture occurrence following burn injuries is unclear. The objective of this study was to evaluate postintervention incidence of fractures in children during the rehabilitative phase postburn (PB) following participation in a randomized clinical trial of vitamin D supplementation.

MATERIALS AND METHODS

Follow-up for fracture evaluation was obtained in 39 of 50 patients randomized to daily enteral vitamin D2, D3, or placebo throughout the acute burn course. Serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, D2, D3, calcitonin, and bone alkaline phosphatase (BAP) measurements were obtained PB day 7, midpoint, discharge, and 1-year PB. Urinary calcium was obtained PB day 7 and midpoint. Dual-energy x-ray absorptiometry (DXA) was performed at discharge and 1-year PB.

RESULTS

Fractures were reported in 6 of 39 respondents. Four fractures occurred in the placebo group, 2 in the D2 group, and none in the D3 group. Serum vitamin D, calcitonin, BAP, and urinary calcium were similar between fracture groups. The group with fracture morbidity had larger burn size (83.8% ± 4.9% vs 53.0% ± 2.9%, P < .0001), greater full-thickness burn (69.7% ± 9.4% vs 39.4% ± 4.1%, P = .02), and increased incidence of inhalation injury (33% vs 6%, P = .04). Decreased bone mineral density z score was noted at discharge in the placebo fracture compared with no-fracture group (P < .05).

CONCLUSION

This preliminary report suggests there may be benefit of vitamin D3 in reducing postdischarge fracture risk. Results reaffirm the importance of monitoring bone health in pediatric patients postburn.

Genetic polymorphisms related to vitamin D and the therapeutic potential of vitamin D in multiple sclerosis

Vitamin D receptors (VDRs), which are responsible for most vitamin D functions, are expressed on various immune cells. Vitamin D is considered to be a potent immunomodulator. A variety of cells in the central nervous system (CNS) also express VDRs; thus, vitamin D may play a role in the regulation of neurodegeneration and repair processes within the CNS. Considered together with epidemiological studies, low vitamin D status is reckoned to be one of the risk factors for multiple sclerosis (MS). Further, vitamin D is considered to be a possible treatment for MS. However, previous clinical trials with small cohorts have not demonstrated significant effects of vitamin D in MS. Current ongoing clinical trials with large cohorts could provide answers with respect to the clinical effects of vitamin D in MS. However, genetic studies have suggested that genes associated with vitamin D, including VDRs, are susceptible genes for MS. Vitamin D needs to be considered from the perspective of the interaction between vitamin-D-related genetic factors and environmental factors affecting vitamin D levels.

Increases in pre-hospitalization serum 25(OH)D concentrations are associated with improved 30-day mortality after hospital admission: A cohort study

CONTEXT

Pre-hospital vitamin D status may be a modifiable risk factor for all-cause mortality among hospitalized patients.

OBJECTIVE

To examine the association between increases in serum 25-hydroxyvitamin D [25(OH)D] levels during the year before hospitalization and risk of 30-day all-cause mortality after hospital admission.

DESIGN

Retrospective cohort study.

SETTING

Two Boston teaching hospitals.

PATIENTS OR OTHER PARTICIPANTS

We studied 4344 adults hospitalized between 1993 and 2011 who had serum 25(OH)D concentrations measured at least twice within 7-365 days before the index hospitalization.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The exposure of interest was change in pre-hospital serum 25(OH)D concentrations. The main outcome was 30-day all-cause mortality. We used mixed-effects logistic regression to describe how 30-day mortality differed with changes in pre-hospital 25(OH)D concentrations. Additionally, the odds of 30-day mortality in patients with pre-hospital 25(OH)D increases of ≥10 ng/mL was compared to that of patients with increases of <10 ng/mL.

RESULTS

In a mixed-effect logistic regression model adjusted for age, gender, race, type (medical/surgical), Deyo-Charlson Index, creatinine and hematocrit, 30-day all-cause mortality rate was 8% (95%CI: 1-15) lower for each 10 ng/mL increase in pre-hospital 25(OH)D (P = 0.025) compared with the 30-day all-cause mortality rate in the entire cohort. In an adjusted logistic regression model, absolute changes of ≥10 ng/mL in patients with initial 25(OH)D concentrations < 20 ng/mL (n = 1944) decreased the odds of 30-day all-cause mortality by 48% (adjusted OR 0.52; 95%CI 0.30-0.93; P = 0.026) compared to patients with changes of <10 ng/mL.

CONCLUSIONS

In patients with initial 25(OH)D < 20 ng/mL, subsequent improvements in vitamin D status before hospitalization are associated with decreased odds of 30-day all-cause mortality after hospital admission. A causal relation may not be inferred from this observational study.

Vitamin D as an Immunomodulator: Risks with Deficiencies and Benefits of Supplementation

Vitamin D refers to a class of fat-soluble secosteroids often associated with their role in absorption and metabolism of minerals such as calcium and phosphate. In recent years, our understanding of vitamin D has expanded to include its role in modulating the immune system. Of particular focus are the effects of vitamin D deficiency and supplementation on patients suffering from disorders due to dysregulation of the immune system. In patients with multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease, deficiencies in vitamin D have been associated with an increased risk of disease activity. In this review, we will look at the current state of research in regards to the relationship between vitamin D and immune-dysregulation. We will focus on both the risks associated with vitamin D deficiency as well as the benefits of vitamin D supplementation.

Efficacy of high-dose vitamin D3 supplementation in vitamin D deficient pregnant women with multiple sclerosis: Preliminary findings of a randomized-controlled trial

BACKGROUND

The aim of this preliminary study was to assess the safety and efficacy of high-dose oral vitamin D3 supplementation during pregnancy in women with multiple sclerosis (MS) in Isfahan, Iran.

METHODS

In a single center open-label randomized, controlled clinical Phase I/II pilot study, 15 pregnant women with confirmed MS with low serum 25-hydroxyvitamin D (25(OH)D) levels were randomly allocated to receive either 50,000 IU/week vitamin D3 or routine care from 12 to 16 weeks of gestation till delivery. The main outcome measures were mean change in serum 25(OH)D levels, expanded disability status scale (EDSS) score, and number of relapse events during pregnancy and within 6 months after delivery.

RESULTS

Average serum 25(OH)D level at the end of trial in vitamin D3 supplemented group was higher than routine care group (33.7 ng/mL vs. 14.6 ng/ml, P < 0.050). In vitamin D3 group, the mean EDSS did not changed 6 months after delivery (P > 0.050), whereas in routine care group, the mean EDSS increased from 1.3 (0.4) to 1.7 (0.6) (P < 0.070). Women in vitamin D3 group appeared to have fewer relapse events during pregnancy and within 6 months after delivery. No significant adverse events occurred.

CONCLUSION

Adding high dose vitamin D3 supplementation during pregnancy to routine care of women with MS had significant effect on the serum 25(OH)D levels, EDSS and number of relapse events during pregnancy and within 6 months after delivery.

Effects of vitamin D on retinal nerve fiber layer in vitamin D deficient patients with optic neuritis: Preliminary findings of a randomized, placebo-controlled trial

BACKGROUND

There is accumulating evidence for a possible protective role of vitamin D in the development and disease course of multiple sclerosis. Whether vitamin D is also effective in treating patients with optic neuritis (ON) is not known. The aim of this study was to evaluate the effect of oral vitamin D on the thickness of retinal nerve fiber layer (RNFL) in vitamin D deficient patients with ON by optical coherence tomography.

MATERIALS AND METHODS

A Phase II placebo-controlled randomized clinical trial conducted between July 2011 and November 2012 included 52 patients with confirmed unilateral ON aged 15-38 years and low serum 25-hydroxyvitamin D levels. The main outcome measures were changes in thickness of RNFL and macula 6 months after treatment. Patients were randomly allocated to receive 6 months of treatment with adding either 50,000 IU/week vitamin D or placebo.

RESULTS

In the 27 patients treated with vitamin D, the mean (standard deviation [SD]) thickness of RNFL decreased from 111.3 (18.9) μm at baseline to 91.4 (13.3) at the end of study period (P < 0.001). Correspondingly, in the 25 patients treated with placebo, the mean (SD) thickness of RNFL decreased from 113.7 (21.5) μm at baseline to 96.1 (12.3) at the end of study period (P < 0.01). In both groups, the mean thickness of the macula did not changed (P > 0.05). Average thickness of RNFL at the end of trial did not differ between groups.

CONCLUSION

Adding vitamin D to routine disease therapy had no significant effect on the thickness of RNFL or macula in patients with ON. This trial is registered on www.clinicaltrials.gov (ID NCT01465893).

Vitamin D Actions on CD4(+) T Cells in Autoimmune Disease

This review summarizes and integrates research on vitamin D and CD4⁺ T-lymphocyte biology to develop new mechanistic insights into the molecular etiology of autoimmune disease. A deep understanding of molecular mechanisms relevant to gene–environment interactions is needed to deliver etiology-based autoimmune disease prevention and treatment strategies. Evidence linking sunlight, vitamin D, and the risk of multiple sclerosis and type 1 diabetes is summarized to develop the thesis that vitamin D is the environmental factor that most strongly influences autoimmune disease development. Evidence for CD4⁺ T-cell involvement in autoimmune disease pathogenesis and for paracrine calcitriol signaling to CD4⁺ T lymphocytes is summarized to support the thesis that calcitriol is sunlight’s main protective signal transducer in autoimmune disease risk. Animal modeling and human mechanistic data are summarized to support the view that vitamin D probably influences thymic negative selection, effector Th1 and Th17 pathogenesis and responsiveness to extrinsic cell death signals, FoxP3⁺CD4⁺ T-regulatory cell and CD4⁺ T-regulatory cell type 1 (Tr1) cell functions, and a Th1–Tr1 switch. The proposed Th1–Tr1 switch appears to bridge two stable, self-reinforcing immune states, pro- and anti-inflammatory, each with a characteristic gene regulatory network. The bi-stable switch would enable T cells to integrate signals from pathogens, hormones, cell–cell interactions, and soluble mediators and respond in a biologically appropriate manner. Finally, unanswered questions and potentially informative future research directions are highlighted to speed delivery of etiology-based strategies to reduce autoimmune disease.

Vitamin D supplementation in the ICU patient

PURPOSE OF REVIEW

Recent findings suggest that vitamin D is a marker for outcomes in critical illness. The purpose of this review is to summarize current biological, observational and interventional evidence in the critically ill.

RECENT FINDINGS

Both biological and observational studies support the role of vitamin D deficiency in adverse critical illness outcomes. Interventional trials of critically ill patients show that to improve vitamin D status, high-dose vitamin D3 is required. Critically ill patients have a relatively blunted response to vitamin D supplementation compared to the general outpatient population. Toxicity from high-dose vitamin D in trials in the critically ill has been limited to mild hypercalcemia. Recent evidence suggests that treatment of severely vitamin D-deficient critically ill patients with high-dose vitamin D early in the ICU course may improve mortality.

SUMMARY

Vitamin D deficiency is a potentially modifiable marker for adverse outcomes in critical illness and critical illness survivors. Vitamin D supplementation is inexpensive and appears safe in critical illness trials. A well powered interventional trial is required to determine the definitive answer regarding the role of vitamin D supplementation in the improvement of critical care outcomes. Until such data are available, a cautious approach to correction of vitamin D status in the ICU is warranted.

Vitamin D status and effect of interferon-β1a treatment on MRI activity and serum inflammation markers in relapsing-remitting multiple sclerosis

To explore if vitamin D modulates interferon-β1a treatment effects in relapsing-remitting multiple sclerosis, we examined relationships between serum vitamin D and magnetic resonance imaging (MRI) activity and ten systemic inflammation markers in 88 patients, before and during treatment. Odds ratios for all MRI parameters were negatively associated with vitamin D levels before therapy, but converged to equally low values irrespective of vitamin D status during treatment. During therapy, similar alterations of MRI activity and inflammation markers were found across patients categorized by mean vitamin D values. This suggests that vitamin D status has no major influence on interferon-β1a treatment effects.

Role of the immunogenic and tolerogenic subsets of dendritic cells in multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disorder in the central nervous system (CNS) characterized by inflammation and demyelination as well as axonal and neuronal degeneration. So far effective therapies to reverse the disease are still lacking; most therapeutic drugs can only ameliorate the symptoms or reduce the frequency of relapse. Dendritic cells (DCs) are professional antigen presenting cells (APCs) that are key players in both mediating immune responses and inducing immune tolerance. Increasing evidence indicates that DCs contribute to the pathogenesis of MS and might provide an avenue for therapeutic intervention. Here, we summarize the immunogenic and tolerogenic roles of DCs in MS and review medicinal drugs that may affect functions of DCs and have been applied in clinic for MS treatment. We also describe potential therapeutic molecules that can target DCs by inducing anti-inflammatory cytokines and inhibiting proinflammatory cytokines in MS.

Vitamin D3 administration to MS patients leads to increased serum levels of latency activated peptide (LAP) of TGF-beta

BACKGROUND

Deficiency of vitamin D is an environmental risk factor for MS. Vitamin D has immunomodulatory effects, including promotion of T-cell differentiation into T-regulatory cells, which produces regulatory cytokines including TGF-β. Increasing serum vitamin D levels have been associated with decreased disease activity in MS patients, but there are only few studies concerning the immunological effects of vitamin D supplementation in MS. In this study we investigated the effect of weekly supplementation of vitamin D3 or placebo on serum levels of multiple cytokines in patients with relapsing remitting MS.

METHODS

The study was conducted on the patient cohort of the Finnish Vitamin D study. All patients were using IFN-beta-1b and were randomized to add-on treatment with either cholecalciferol 20,000 IU/week or placebo. Concentrations of LAP (TGF-β), INF-γ, IL-17A, IL-2, IL-10, IL-9, IL-22, IL-6, IL-13, IL-4, IL-5, IL-1β and TNF-α were determined at screening and at 12 months using commercial fluorescent bead immunoassay kits.

RESULTS

LAP (TGF-β) levels increased significantly in the vitamin D treated group from a mean of 47 (SE 11) pg/ml to 55 (SE 14) pg/ml in 12 months (p-value=0.0249). Placebo treatment had no significant effect on LAP levels. The levels of the other cytokines did not change significantly in either group.

CONCLUSIONS

We showed increased serum latency activated peptide (LAP) of TGF-β levels in MS patients treated with vitamin D3. The immune regulatory effects of TGF-beta may play a role in the improved MRI outcomes that we observed earlier in the vitamin D treated group of patients.

Short-term effect of high-dose vitamin D on the level of interleukin 10 in patients with multiple sclerosis: a randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system. Vitamin D has been related to the prevention of MS and to modulating its course. Recent studies have shown the safety of high-dose vitamin D in MS.

OBJECTIVE

This study compared the effects of high-dose vitamin D on interleukin 10 (IL-10) levels in MS patients in a double-blind, randomized clinical trial.

METHODS

Ninety-four patients with relapsing remitting MS (RRMS) were randomized into a treatment and a placebo group. Both groups received conventional MS treatment. The intervention group received 50,000 IU of vitamin D every 5 days for 3 months. IL-10 was measured at baseline and after 3 months.

RESULTS

Serum levels of IL-10 were (median ± IQR): 12.58 ± 11.97 and 10.97 ± 9.97 pg/ml in the intervention and placebo groups, respectively, at baseline (p = 0.161); after 3 months, these levels were 13.76 ± 18.95 and 11.31 ± 19.63 pg/ml, respectively (p = 0.158). The IL-10 level increased significantly after receiving high-dose vitamin D for 3 months (β = 0.737, p = 0.015 and R2 = 0.91).

CONCLUSION

IL-10 levels increased significantly in RRMS patients after taking high-dose vitamin D3 for 3 months. High-dose vitamin D might be useful in promoting an anti-inflammatory state in RRMS patients.

Vitamin D and immunity

Vitamin D deficiency has been linked to an increased risk of a wide range of adverse health outcomes. The active form of vitamin D has an important role in calcium metabolism and in bone mineralisation, but the evidence for other health outcomes is mixed, with the strongest effects seen in the weakest epidemiological study designs. There are plausible pathways whereby vitamin D deficiency can impair immune function, resulting in both overactivity and increased risk of autoimmune disease, as well as immune suppression with poorer resistance to infection. Vitamin D status may influence the bacterial flora that constitute the microbiome and affect immune function through this route. Exposure of the skin to ultraviolet radiation causes the production of a range of chemicals, including vitamin D, and new research is exploring possible vitamin D-independent immunomodulatory pathways.

"Disease modifying nutricals" for multiple sclerosis

The association between vitamin D and multiple sclerosis has (re)-opened new interest in nutrition and natural compounds in the prevention and treatment of this neuroinflammatory disease. The dietary amount and type of fat, probiotics and biologicals, salmon proteoglycans, phytoestrogens and protease inhibitor of soy, sodium chloride and trace elements, and fat soluble vitamins including D, A and E were all considered as disease-modifying nutraceuticals. Studies in experimental autoimmune encephalomyelitis mice suggest that poly-unsaturated fatty acids and their 'inflammation-resolving' metabolites and the gut microflora may reduce auto-aggressive immune cells and reduce progression or risk of relapse, and infection with whipworm eggs may positively change the gut-brain communication. Encouraged by the recent interest in multiple sclerosis-nutrition nature's pharmacy has been searched for novel compounds with anti-inflammatory, immune-modifying and antioxidative properties, the most interesting being the scorpion toxins that inhibit specific potassium channels of T cells and antioxidative compounds including the green tea flavonoid epigallocatechin-3-gallate, curcumin and the mustard oil glycoside from e.g. broccoli and sulforaphane. They mostly also inhibit pro-inflammatory signaling through NF-κB or toll-like receptors and stabilize the blood brain barrier. Disease modifying functions may also complement analgesic and anti-spastic effects of cannabis, its constituents, and of 'endocannabinoid enhancing' drugs or nutricals like inhibitors of fatty acid amide hydrolase. Nutricals will not solve multiple sclerosis therapeutic challenges but possibly support pharmacological interventions or unearth novel structures.

The co-occurrence of multiple sclerosis and type 1 diabetes: shared aetiologic features and clinical implication for MS aetiology

We reviewed the evidence for the co-occurrence of type 1 diabetes mellitus (T1D) and multiple sclerosis (MS), and assessed the clinical significance of this association and the shared aetiological features of the two diseases. T1D and MS contribute considerably to the burden of autoimmune diseases in young adults. The co-occurrence of MS and T1D has been reported by a number of studies, suggesting that the two conditions share one or more aetiological components. Both conditions have been associated with distinct human leukocyte antigen (HLA) haplotypes but share a number of similarities in clinical, epidemiological and immunological features, leading to suggestions of possible common mechanisms of development. While underlying genetic factors may be important for the co-occurrence of both conditions, some evidence suggests that environmental factors such as vitamin D deficiency may also modulate an individual's risk for the development of both conditions. Evidence on whether the co-occurrence of the two autoimmune conditions will affect the disease course and severity of MS is merely absent. Further studies need to be conducted to ascertain whether the neuropathology associated with T1D might influence the disease course and contribute to the severity of MS.

The vitamin D to ameliorate multiple sclerosis (VIDAMS) trial: study design for a multicenter, randomized, double-blind controlled trial of vitamin D in multiple sclerosis

BACKGROUND

Lower levels of vitamin D are associated with increased MS risk and with greater clinical and brain MRI activity in established relapsing MS.

OBJECTIVE

The VIDAMS trial (NCT01490502) is evaluating whether high-dose vitamin D supplementation reduces the risk of MS activity.

DESIGN/METHODS

Eligibility criteria include diagnosis of RRMS, age 18 to 50 years, and Expanded Disability Status Scale ≤4.0. Disease duration and activity requirements depend on whether 2005 or 2010 criteria are used for diagnosis. Enrollment is restricted based on prior MS therapy exposure and recent vitamin D use. After completing a one-month run-in of glatiramer acetate, 172 patients will be randomized 1:1 to oral vitamin D(3) 5000 IU versus 600 IU daily. Clinical visits occur every 12 weeks for 96 weeks.

RESULTS

Sixteen sites throughout the United States are participating in the trial. Complete enrollment is expected by late 2014, with follow-up through 2016. No interim analyses are planned. The primary outcome for the trial is the proportion of patients experiencing a relapse in each group. Other clinical, patient-reported, and MRI outcomes will be evaluated.

CONCLUSIONS

The VIDAMS trial will provide critical information about the safety and efficacy of vitamin D therapy in RRMS, with implications for MS patients worldwide.

Is there an association between diabetic neuropathy and low vitamin D levels?

In the past few years, the effects of vitamin D that go beyond its relationship with bone metabolism have come into the focus of scientific attention. Research concerning diabetes and its complications has become a public health priority. An increasing number of reports link vitamin D deficiency to diabetes; however, so far, there has only been limited and contradictory data available on the correlation between diabetic peripheral neuropathy and vitamin D. Studies of people with type 2 diabetes confirmed the relationship between vitamin D deficiency and neuropathy incidence as well as the severity of the symptoms caused by neuropathy. The latest studies are also suggesting a relationship between the incidence of plantar ulcers and vitamin D deficiency.

Treatment Optimization in MS: Canadian MS Working Group Updated Recommendations

The Canadian Multiple Sclerosis Working Group (CMSWG) developed practical recommendations in 2004 to assist clinicians in optimizing the use of disease-modifying therapies (DMT) in patients with relapsing multiple sclerosis. The CMSWG convened to review how disease activity is assessed, propose a more current approach for assessing suboptimal response, and to suggest a scheme for switching or escalating treatment. Practical criteria for relapses, Expanded Disability Status Scale (EDSS) progression and MRI were developed to classify the clinical level of concern as Low, Medium and High. The group concluded that a change in treatment may be considered in any RRMS patient if there is a high level of concern in any one domain (relapses, progression or MRI), a medium level of concern in any two domains, or a low level of concern in all three domains. These recommendations for assessing treatment response should assist clinicians in making more rational choices in their management of relapsing MS patients.

Molecular mechanism underlying the impact of vitamin D on disease activity of MS

OBJECTIVE

Some previous studies suggest modest to strong effects of 25-hydroxyvitamin D (25(OH)D) on multiple sclerosis (MS) activity. The objective of this study was to explore the mechanistic rationale that may explain potential clinical effects of 25(OH)D.

METHODS

This study measured serum 25(OH)D levels and global gene expression profiles over a course of up to 2 years in patients starting treatment with interferon beta-1b (IFNB-1b) after a clinically isolated syndrome. MS disease activity was assessed by the number of gadolinium-enhancing lesions present on repeated magnetic resonance imaging (MRIs).

RESULTS

The number of gadolinium-enhancing lesions was highly significantly associated with 25(OH)D levels. Conducting various systems-level analyses on the molecular level, multiple lines of evidence indicated that 25(OH)D regulates expression dynamics of a large gene-gene interaction system which primarily regulates immune modulatory processes modulating MS activity. The vitamin D response element was significantly enriched in this system, indicating a direct regulation of this gene interaction network through the vitamin D receptor. With increasing 25(OH)D levels, resulting regulation of this system was associated with a decrease in MS activity. Within the complex network of genes that are regulated by 25(OH)D, well-described targets of IFNB-1b and a regulator of sphingosine-1-phosphate bioavailability were found. The 25(OH)D effects on MS activity were additively enhanced by IFNB-1b.

INTERPRETATION

Here, we provide mechanistic evidence that an unbalanced 25(OH)D gene expression system may affect MS activity. Our findings support a potential benefit of monitoring and managing vitamin D levels (e.g., through supplementation) in early MS patients treated with IFN-beta-1b.

The VITAH trial VITamin D supplementation and cardiac Autonomic tone in Hemodialysis: a blinded, randomized controlled trial

Background

Patients with end-stage kidney disease (ESKD) have a high rate of mortality and specifically an increased risk of sudden cardiac death (SCD). Impaired cardiac autonomic tone is associated with elevated risk of SCD. Moreover, patients with ESKD are often vitamin D deficient, which we have shown may be linked to autonomic dysfunction in humans. To date, it is not known whether vitamin D supplementation normalizes cardiac autonomic function in the high-risk ESKD population. The VITamin D supplementation and cardiac Autonomic tone in Hemodialysis (VITAH) randomized trial will determine whether intensive vitamin D supplementation therapies improve cardiac autonomic tone to a greater extent than conventional vitamin D supplementation regimens in ESKD patients requiring chronic hemodialysis.

Methods/Design

A total of 60 subjects with ESKD requiring thrice weekly chronic hemodialysis will be enrolled in this 2x2 crossover, blinded, randomized controlled trial. Following a 4-week washout period from any prior vitamin D therapy, subjects are randomized 1:1 to intensive versus standard vitamin D therapy for 6 weeks, followed by a 12-week washout period, and finally the remaining treatment arm for 6 weeks. Intensive vitamin D treatment includes alfacalcidiol (activated vitamin D) 0.25mcg orally with each dialysis session combined with ergocalciferol (nutritional vitamin D) 50 000 IU orally once per week and placebo the remaining two dialysis days for 6 weeks. The standard vitamin D treatment includes alfacalcidiol 0.25mcg orally combined with placebo each dialysis session per week for 6 weeks. Cardiac autonomic tone is measured via 24 h Holter monitor assessments on the first dialysis day of the week every 6 weeks throughout the study period. The primary outcome is change in the low frequency: high frequency heart rate variability (HRV) ratio during the first 12 h of the Holter recording at 6 weeks versus baseline. Secondary outcomes include additional measures of HRV. The safety of intensive versus conventional vitamin D supplementation is also assessed.

Discussion

VITAH will determine whether an intensive vitamin D supplementation regimen will improve cardiac autonomic tone compared to conventional vitamin D supplementation and will assess the safety of these two supplementation regimens in ESKD patients receiving chronic hemodialysis.

Trial registration

ClinicalTrials.gov, NCT01774812

Vitamin D in inflammatory diseases

Changes in vitamin D serum levels have been associated with inflammatory diseases, such as inflammatory bowel disease (IBD), rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis (MS), atherosclerosis, or asthma. Genome- and transcriptome-wide studies indicate that vitamin D signaling modulates many inflammatory responses on several levels. This includes (i) the regulation of the expression of genes which generate pro-inflammatory mediators, such as cyclooxygenases or 5-lipoxygenase, (ii) the interference with transcription factors, such as NF-κB, which regulate the expression of inflammatory genes and (iii) the activation of signaling cascades, such as MAP kinases which mediate inflammatory responses. Vitamin D targets various tissues and cell types, a number of which belong to the immune system, such as monocytes/macrophages, dendritic cells (DCs) as well as B- and T cells, leading to individual responses of each cell type. One hallmark of these specific vitamin D effects is the cell-type specific regulation of genes involved in the regulation of inflammatory processes and the interplay between vitamin D signaling and other signaling cascades involved in inflammation. An important task in the near future will be the elucidation of the regulatory mechanisms that are involved in the regulation of inflammatory responses by vitamin D on the molecular level by the use of techniques such as chromatin immunoprecipitation (ChIP), ChIP-seq, and FAIRE-seq.

Vitamin D and inflammatory diseases

Beyond its critical function in calcium homeostasis, vitamin D has recently been found to play an important role in the modulation of the immune/inflammation system via regulating the production of inflammatory cytokines and inhibiting the proliferation of proinflammatory cells, both of which are crucial for the pathogenesis of inflammatory diseases. Several studies have associated lower vitamin D status with increased risk and unfavorable outcome of acute infections. Vitamin D supplementation bolsters clinical responses to acute infection. Moreover, chronic inflammatory diseases, such as atherosclerosis-related cardiovascular disease, asthma, inflammatory bowel disease, chronic kidney disease, nonalcoholic fatty liver disease, and others, tend to have lower vitamin D status, which may play a pleiotropic role in the pathogenesis of the diseases. In this article, we review recent epidemiological and interventional studies of vitamin D in various inflammatory diseases. The potential mechanisms of vitamin D in regulating immune/inflammatory responses in inflammatory diseases are also discussed.

Vitamin D status and the risk of multiple sclerosis: a systematic review and meta-analysis

To estimate the associations between vitamin D status and multiple sclerosis (MS). We searched electronic databases of the human literature in PubMed, EMBASE and the Cochrane Library up to February, 2014 using the following keywords: 'vitamin D' or '25(OH)D' and 'status' or 'deficiency' or 'insufficiency' and 'multiple sclerosis'. A systematic review and meta-analysis were conducted on observational studies that reported the association between blood vitamin D levels and MS. Eleven studies met the inclusion criteria. 1007 patients and 829 controls were included. Results of our meta-analysis show that MS patients had lower mean levels of 25-hydroxyvitamin D [25(OH)D] than healthy controls (weighted mean difference[MD], -14.52, 95% confidence interval [CI], -23.83 to -5.22). There were statistically significant heterogeneity (P<0.00001; I(2)=92%). The significant heterogeneity may be due to the differences in ethnicity, country, season of blood sampling and age of the participants studied. To sum up, low vitamin D levels are associated with an increased risk of MS.

Vitamin D in systemic and organ-specific autoimmune diseases

Lately, vitamin D has been linked with metabolic and immunological processes, which established its role as an essential component of human health preservation. Vitamin D has been defined as natural immune modulators, and upon activation of its receptors (VDRs), it regulates calcium metabolism, cellular growth, proliferation and apoptosis, and other immunological functions. Epidemiological data underline a strong correlation between poor vitamin D status and higher risk for chronic inflammatory illnesses of various etiologies, including autoimmune diseases. Epidemiological, genetic, and basic studies indicated a potential role of vitamin D in the pathogenesis of certain systemic and organ-specific autoimmune diseases. These studies demonstrate correlation between low vitamin D and prevalence of diseases. In addition, VDRs' polymorphisms observed in some of these autoimmune diseases may further support a plausible pathogenic link. Notably, for some autoimmune disease, no correlation with vitamin D levels could be confirmed. Thus, in the current review we present the body of evidence regarding the plausible roles of vitamin D and VDR's polymorphism in the pathogenesis of autoimmunity. We summarize the data regarding systemic (i.e., systemic lupus erythematosus, rheumatoid arthritis, etc.) and organ-specific (i.e., multiple sclerosis, diabetes mellitus, primary biliary cirrhosis, etc.) autoimmune diseases, in which low level of vitamin D was found comparing to healthy subjects. In addition, we discuss the correlations between vitamin D levels and clinical manifestations and/or activity of diseases. In this context, we address the rational for vitamin D supplementation in patients suffering from autoimmune diseases. Further studies addressing the mechanisms by which vitamin D affects autoimmunity and the proper supplementation required are needed.

[Vitamin D and neuropathy]

Diabetes is a widespread disease and, therefore, studies dealing with diabetes and its complications are very important for public health. Numerous reports link vitamin D deficiency to the increased risk of diabetes mellitus and complications such as neuropathy. However, there are limited and conflicting data available on vitamin D deficiency in patients with diabetic peripheral neuropathy. Studies in type 2 diabetics confirmed the relationship between vitamin D deficiency and incidence of neuropathy. Recent reports suggest a relationship between the incidence of plantar ulcers and vitamin D deficiency.