Vitamin D, invariant natural killer T-cells and experimental autoimmune disease

Maternal vitamin D deficiency aggravates the dysbiosis of gut microbiota by affecting intestinal barrier function and inflammation in obese male offspring mice

OBJECTIVES

The colonization of gut microbiota during early life may play a critical role in the progression of metabolic syndrome in adulthood. Targeting gut-based genes in the barrier function, inflammation, and lipid transportation are potential therapies for obesity. Therefore, this study focused on whether maternal deficient vitamin D (VD) intake could aggravate the dysbiosis of gut microbiota by affecting the expressions of these genes in the ileum and colon of obese male offspring mice.

METHODS

Four-week-old female C57 BL/6 J mice were fed normal (VD-C) or VD-deficient (VD-D) reproductive diets throughout pregnancy and lactation (n = 15/group). Weaning male pups (n = 10/group) were fed either a high-fat (HFD; VD-C-HFD, VD-D-HFD) or normal-fat diet (control) for 16 wk. All biologic samples were obtained after the mice were anesthetized by cervical dislocation. Subsequently, the compositions of the gut microbiota in cecal contents were analyzed using 16 S ribosomal RNA sequencing. Messenger RNA expression in the ileum and colon was determined using real-time reverse transcription-polymerase chain reaction. The distributions of ZO-1 and Claudin-1 were determined using immunohistochemistry testing.

RESULTS

Maternal deficient VD intake significantly aggravated the dysbiosis of gut microbiota persisting into adulthood from phylum to genus levels in the cecal contents among obese male offspring mice. This aggravation led to significantly depleted Bacteroidetes and Verrucomicrobia (Akkermansia, Alliprevotella, and Bacteroides), with higher relative abundance of Firmicutes (Lactobacillus, Lachnoclostridium, Romboutsia, and Ruminiclostridium_9) and Firmicutes/Bacteroidetes. The gene expressions of proinflammatory cytokines (Ccl2, Ccl4 and interleukin-1β) and lipid transportation molecules (Ffar3, Fabp4, and Fabp1) were higher, and the levels of intestinal barrier function (Occludin, ZO-1, and Claudin-1) were lower in the VD-D-HFD group than those in the VD-C-HFD group. Furthermore, there were significant correlations between the dysbiosis of intestinal microbials and expressions of genes related to barrier function, inflammation, and lipid transportation in the ileum and/or colon.

CONCLUSIONS

Maternal VD deficiency during pregnancy and lactation could aggravate the dysbiosis of gut microbiota to affect the progression of obesity among male offspring, which might be regulated by genes associated with barrier function, inflammation, and lipid transportation. So early life appropriate VD intake could play a significant role in preventing later obesity.

The correlation between serum 25-hydroxy-vitamin D levels and anti-SARS-CoV-2 S-RBD IgG and neutralizing antibody levels among cancer patients receiving COVID-19 vaccines

Introduction

During the coronavirus disease 2019 (COVID-19) pandemic, vitamin D has been established as an immune-modulator that reduces pro-inflammatory damage which effectively diminish the severity of COVID-19. Vitamin D also has a significant effect against influenza and dengue and increase the seroconversion following influenza vaccination. To date, the role of vitamin D in optimizing the efficacy of COVID-19 vaccines remains unclear. This study aimed to analyze the correlation between serum 25-hydroxy-cholecalciferol or 25(OH)D levels and anti-SARS-CoV-2 S-RBD IgG and neutralizing antibody levels among cancer patients.

Methodology

A multicenter cross-sectional study was conducted among solid and hematologic cancer patients who were vaccinated with two doses of the same types of COVID-19 vaccines (either mRNA, non-replicating viral vector, or inactivated) within 6 months.

Result

The median serum 25(OH)D level in 119 cancer patients was 36.36 [IQR = 30.30] ng/mL. The seropositivity of S-RBD IgG and NAb reached 93.3 and 94.1%, respectively. The S-RBD IgG level was significantly higher in the sufficient group (median = 414.07 [1,441.83] AU/mL) than in the deficient group (median = 91.56 [652.00] AU/mL) (p-value = 0.049). Among non-chemotherapy subjects, the anti-SARS-CoV-2 S-RBD IgG levels had a significant positive correlation with 25(OH)D levels (p-value = 0.03; R = 0.588). The NAb levels also showed significantly positive correlation with 25(OH)D level (p-value = 0.005; R = 0.561). The 25(OH)D levels were positively correlated with S-RBD IgG levels among subjects younger than 60 years old (p-value = 0.047; R = 0.136). However, serum 25 (OH)D levels showed no such correlation with S-RBD IgG levels among subjects older than 60 years old (p-value = 0.933; R = 0.136).

Conclusion

Both anti-SARS-CoV-2 S-RBD IgG and NAb levels developed moderate correlation with 25(OH)D levels among subjects treated without chemotherapy. The S-RBD IgG levels also had positive correlation with 25(OH)D levels among subjects younger than 60 years old. Thus, we recommended cancer patients to maintain serum 25(OH)D levels above 30 ng/mL (75 nmol/L) to enhance the efficacy of COVID-19 vaccines.

An Update on the Effects of Vitamin D on the Immune System and Autoimmune Diseases

Vitamin D intervenes in calcium and phosphate metabolism and bone homeostasis. Experimental studies have shown that 1,25-dihydroxyvitamin D (calcitriol) generates immunologic activities on the innate and adaptive immune system and endothelial membrane stability. Low levels of serum 25-hydroxyvitamin D (25(OH)D) are associated with an increased risk of developing immune-related diseases such as psoriasis, type 1 diabetes, multiple sclerosis, and autoimmune diseases. Various clinical trials describe the efficacy of supplementation of vitamin D and its metabolites for treating these diseases that result in variable outcomes. Different disease outcomes are observed in treatment with vitamin D as high inter-individual difference is present with complex gene expression in human peripheral blood mononuclear cells. However, it is still not fully known what level of serum 25(OH)D is needed. The current recommendation is to increase vitamin D intake and have enough sunlight exposure to have serum 25(OH)D at a level of 30 ng/mL (75 nmol/L) and better at 40–60 ng/mL (100–150 nmol/L) to obtain the optimal health benefits of vitamin D.

An Overview of Systematic Reviews of the Role of Vitamin D on Inflammation in Patients with Diabetes and the Potentiality of Its Application on Diabetic Patients with COVID-19

Almost two years have passed since the outbreak reported for the first time in Wuhan of coronavirus disease 2019 (COVID-19), due to severe acute respiratory syndrome (SARS)-CoV-2 coronavirus, rapidly evolved into a pandemic. This infectious disease has stressed global health care systems. The mortality rate is higher, particularly in elderly population and in patients with comorbidities such as hypertension, diabetes mellitus, cardiovascular disease, chronic lung disease, chronic renal disease, and malignancy. Among them, subjects with diabetes have a high risk of developing severe form of COVID-19 and show increased mortality. How diabetes contributes to COVID-19 severity remains unclear. It has been hypothesized that it may be correlated with the effects of hyperglycemia on systemic inflammatory responses and immune system dysfunction. Vitamin D (VD) is a modulator of immune-response. Data from literature showed that vitamin D deficiency in COVID-19 patients increases COVID-19 severity, likely because of its negative impact on immune and inflammatory responses. Therefore, the use of vitamin D might play a role in some aspects of the infection, particularly the inflammatory state and the immune system function of patients. Moreover, a piece of evidence highlighted a link among vitamin D deficiency, obesity and diabetes, all factors associated with COVID-19 severity. Given this background, we performed an overview of the systematic reviews to assess the association between vitamin D supplementation and inflammatory markers in patients with diabetes; furthermore, vitamin D’s possible role in COVID-19 patients was assessed as well. Three databases, namely MEDLINE, PubMed Central and the Cochrane Library of Systematic Reviews, were reviewed to retrieve the pertinent data. The aim of this review is to provide insight into the recent advances about the molecular basis of the relationship between vitamin D, immune response, inflammation, diabetes and COVID-19.

The role of NK and NKT cells in the pathogenesis and improvement of multiple sclerosis following disease-modifying therapies

BACKGROUND

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS) that T cells become autoreactive by recognizing CNS antigens. Both innate and adaptive immune systems are involved in the pathogenesis of MS. In recent years, the impact of innate immune cells on MS pathogenesis has received more attention. CD56bright NK cells, as an immunoregulatory subset of NK cells, can increase the production of cytokines that modulate adaptive immune responses, whereas CD56dim NK cells are more active in cytolysis functions. These two main subsets of NK cells may have different effects on the onset or progression of MS. Invariant NKT (iNKT) cells are other immune cells involved in the control of autoimmune diseases; however, variant NKT (vNKT) cells, despite limited information, could play a role in MS remission via an immunoregulatory pathway.

AIM

We aimed to evaluate the influence of MS therapeutic agents on NK and NKT cells and NK cell subtypes.

MATERIALS AND METHODS

The possible mechanism of each MS therapeutic agent has been presented here, focusing on the effects of different disease-modifying therapies on the number of NK and NKT subtypes.

RESULTS

Expansion of CD56bright NK cells, reduction in the CD56dim cells, and enhancement in NKT cells are the more important innate immune cells alterations following the disease-modifying therapies.

CONCLUSION

Expansion of CD56bright NK cells or reduction in the CD56dim cells has been associated with a successful response to different treatments in MS. iNKT and vNKT cells could have beneficial effects on MS improving. It seems that they are enhanced due to some of MS drugs, leading to disease improvement. However, a reduction in the number of NKT cells could be due to the adverse effects of some of MS drugs on the bone marrow.

Impact of Vitamin D Supplementation on Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease affecting a large number of people every year. The exact causal factor for this disease is unclear, but it commonly affects middle-aged women, with known triggers like stress, childbirth, infections, poor diet, lack of sleep, etc.

Many epidemiological studies have indicated that various genetic abnormalities are also critical drivers of the onset of MS. The major risk factors of MS identified include hypovitaminosis D while environmental protective factors include allele HLA DRB1 1501, obesity, Epstein-Barr virus infection, sexual hormones, and smoking.

Our article explores the correlation between the deficiency of vitamin D and the onset and progression of MS. The study uses a systematic review methodology by researching and reviewing scholarly articles exploring the topic. We conducted online searches of literature on Google Scholar and PubMed using the keywords "vitamin D deficiency" and "multiple sclerosis" and accessed the relevant secondary literature sources for review. The variables under study included vitamin D insufficiency as the dependent variable while MS was the independent variable. Causal variables included environmental, genetic, and protective factors.

We hypothesized that there is indeed a correlation between vitamin D deficiency and MS. The findings from our review indicate a strong correlation between the insufficiency of vitamin D and the onset and progression of MS. These results are essential in devising interventions to accomplish primary and secondary prevention of MS, as well as integrating vitamin D supplementation in current treatment protocols for MS.

Vitamin D in infectious complications in critically ill patients with or without COVID-19

25-hydroxyvitamin D [25(OH)D] is an important immunomodulator, whose deficiency may aggravate the incidence and outcome of infectious complications in patients admitted to the intensive care unit. The most recognized extra-skeletal action of vitamin D is the regulation of immune function. Host defense against intracellular pathogens depends upon both innate and adaptive immunity. It has been suggested that vitamin D regulates the pro-inflammatory endothelial response to lipopolysaccharide, rendering it a role in the sepsis cascade. Recent studies have indicated that vitamin D deficiency may be associated with worse outcomes in patients with coronavirus disease 2019 (COVID-19), such as more severe disease and higher mortality rates. To this end, clinical trials with vitamin D supplementation are being carried out in an effort to improve COVID-19 outcomes. In this review, we will discuss the role of vitamin D in the immune response, and more specifically its effect on immune cells. Subsequently, we will provide an overview of the studies that have investigated the predictive value of vitamin D in critical illness outcomes, and its therapeutic value as a supplement in critically ill patients. Finally, the emerging role of vitamin D deficiency in COVID-19 infection risk, and worse outcomes will be discussed.

Immunologic Effects of Vitamin D on Human Health and Disease

Vitamin D is responsible for regulation of calcium and phosphate metabolism and maintaining a healthy mineralized skeleton. It is also known as an immunomodulatory hormone. Experimental studies have shown that 1,25-dihydroxyvitamin D, the active form of vitamin D, exerts immunologic activities on multiple components of the innate and adaptive immune system as well as endothelial membrane stability. Association between low levels of serum 25-hydroxyvitamin D and increased risk of developing several immune-related diseases and disorders, including psoriasis, type 1 diabetes, multiple sclerosis, rheumatoid arthritis, tuberculosis, sepsis, respiratory infection, and COVID-19, has been observed. Accordingly, a number of clinical trials aiming to determine the efficacy of administration of vitamin D and its metabolites for treatment of these diseases have been conducted with variable outcomes. Interestingly, recent evidence suggests that some individuals might benefit from vitamin D more or less than others as high inter-individual difference in broad gene expression in human peripheral blood mononuclear cells in response to vitamin D supplementation has been observed. Although it is still debatable what level of serum 25-hydroxyvitamin D is optimal, it is advisable to increase vitamin D intake and have sensible sunlight exposure to maintain serum 25-hydroxyvitamin D at least 30 ng/mL (75 nmol/L), and preferably at 40-60 ng/mL (100-150 nmol/L) to achieve the optimal overall health benefits of vitamin D.

Evaluation of nasal mucociliary clearance time in patients with Vitamin-D deficiency

OBJECTIVES

The main purpose of the current study was to investigate nasal mucociliary clearance time (NMC) in patients with Vitamin-D deficiency.

METHODS

A total of 55 patients with Vitamin-D deficiency and 32 controls were evaluated. NMC time was measured with subjective saccharine test and compared between study and control groups. In addition, NMC time was re-evaluated after Vitamin-D replacement protocol in patients with Vitamin-D deficiency.

RESULTS

The mean 25(HO)Vitamin-D levels were 14.32 ± 4.23 ng/mL (7-24.6) and 29.38 ± 7.05 ng/mL (25-53.8) in study and control groups, respectively (p < 0.001). The mean NMC time was 11.15 ± 3.05 (6.3-17.6) and 8.40 ± 2.33 (6-13.2) in study and control groups, respectively (p < 0.001). The mean 25(HO)Vitamin-D level after the replacement protocol was 33.38 ± 10.03 and the mean NMC time was 9.56 ± 2.54 (p < 0.001).

CONCLUSION

The mean NMC time was significantly increased in patients with Vitamin-D deficiency which can be corrected after Vitamin-D replacement protocols. The prolonged mucociliary clearance might be one of the pathophysiologic pathways at increased upper respiratory tract infections, and sinonasal and ear infections in patients with Vitamin-D deficiency.

Association of vitamin D receptor expression with inflammatory changes and prognosis of asthma

The expression level of vitamin D receptor in patients with asthma was investigated to study the association between vitamin D receptor and inflammatory changes in asthma. Thirty patients with bronchial asthma treated in the Tianjin Hospital of ITCWM Nankai Hospital were selected as the experimental group, while 30 healthy individuals were selected as the control group. The mRNA expression level of vitamin D receptor in blood was detected via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The protein expression level of vitamin D receptor in blood was detected via western blot analysis and the levels of inflammatory factors were detected via enzyme-linked immune sorbent assay (ELISA). Correlations between the expression level of vitamin D and inflammatory factors were studied via Pearsons analysis. Finally, the prognoses of patients were recorded and analyzed. The results showed that the mRNA and protein expression levels of vitamin D receptor in the experimental group were significantly lower than those in control group (P<0.01). The content of 25-(OH) D₃ in serum in the experimental group was significantly lower than that in the control group (P<0.01). The contents of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in serum in the experimental group were obviously higher than those in the control group, but the contents of IL-10 and transforming growth factor-β (TGF-β) were obviously lower than those in the control group (P<0.01). Moreover, the correlation analysis revealed that IL-6 and TNF-α were negatively correlated with the expression of vitamin D receptor (P<0.05), whereas IL-10 and TGF-β were positively correlated with the expression of vitamin D receptor (P<0.05). In conclusion, the expression of vitamin D receptor is positively correlated with the levels of pro-inflammatory factors. Moreover, the vitamin D receptor affects the prognosis and recovery of lung function of patients with asthma.

Clinical role of vitamin D in prognosis of otitis media with effusion

OBJECTIVE

To investigate the clinical role of Vitamin D in prognosis of Otitis media with effusion.

METHODS

This prospective-controlled study was conducted at otolaryngology department in Duzce University, Turkey. The study group comprised children who were diagnosed with Otitis media with effusion between September 2016 and February 2017. Control group was conducted with children underwent circumcision or inguinal hernia repair operations that confirmed with ENT examination they do not have any sign of otitis media. After 3 months of follow-up without any treatment, unresolved cases who were accepted as chronic otitis media with effusion were operated under general anesthesia for ventilation tube application. Study and control groups were assessed depending on the serum 25(OH)Vitamin D levels at the end of 3 months; < 15 ng/mL was accepted as vitamin D deficiency. The results were compared with the control group in terms of vitamin D levels. Also, subgroup analysis was performed addressing to the complete recovery otitis media with effusion and chronic otitis media with effusion.

RESULTS

One-hundred-seventy-four children with otitis media with effusion and 80 control patients were included to the study. One-hundred-eight (62%) out of 174 patients with otitis media with effusion was completely recovered after a 3-months follow up. Of those 66 out of 174 children, they had persistent diseases, underwent ventilation tube insertion after a 3-months follow-up. The mean 25(OH)Vitamin D level was 18.98 ± 10.60 in otitis media with effusion group and 28.07 ± 14.10 in control group and the difference was statistically significant between the study and control group (p < 0.001). Vitamin D deficiency was observed in 33 out of 66 patients (50.0%) in chronic otitis media with effusion group whilst 35 out of 108 patients (32.4%) in complete recovery otitis media with effusion group (p = 0.021). The rate of 25(OH)Vitamin D deficiency was 25% in control group which was statistically different from chronic otitis media with effusion and recovery chronic otitis media with effusion groups (p = 0.006).

CONCLUSIONS

This study not only shows the relationship between Vitamin D and otitis media with effusion development, but also demonstrates the effects of Vitamin D on otitis media with effusion prognosis. There is a significant association between 25(OH)Vitamin D deficiency and follow-up outcomes of otitis media with effusion.

Lower 25-Hydroxyvitamin D Is Associated with Higher Relapse Risk in Patients with Relapsing-Remitting Multiple Sclerosis

OBJECTIVES

To investigate the association between serum circulating 25-hydroxyvitamin D [25(OH) D] concentrations and exacerbation risk in Chinese patients with relapsing-remitting multiple sclerosis (RR-MS).

METHODS

From January 2014 to December 2014, consecutive RR-MS patients admitted to the Department of Neurology of our hospital were identified. Blood samples for 25(OH) D measurements were taken at admission. All included patients visited the outpatient clinic of our hospital 1 year after admission. The influence of serum 25[OH] D levels on exacerbation was performed by binary logistic regression analysis.

RESULTS

In this study, 109 patients finished the follow-up. Median follow-up time was 1 year (range 1.0-1.1). Twenty-one out of the 109 was at risk period for infection. A total of 32 patients experienced a total of 76 exacerbations during the study. In the follow-up, a total of 32 patients experienced exacerbations. Thus, the exacerbation rate was 29.4% (95%CI: 20.8%-37.9%). Exacerbation rates were found to decrease with increasing levels of serum 25-OH-D concentrations. For the quartiles category, the risk of an exacerbation was significantly increased in the group with first quartile compared to the group with fourth. Rate ratios for the first, second and third group were 4.2, 3.3 and 2.0, respectively (p for trend =0.011) when compared with the fourth group. Simultaneous evaluation of quartile categories of levels of serum 25(OH) D and infections showed that both factors were related to the exacerbation rate.

CONCLUSION

The data demonstrates that lower vitamin D status is a sign of more active disease in patients with RR-MS and suggests a beneficial effect of vitamin D on disease course in MS.

Vitamin D signaling in intestinal innate immunity and homeostasis

The lumen of the gut hosts a plethora of microorganisms that participate in food assimilation, inactivation of harmful particles and in vitamin synthesis. On the other hand, enteric flora, a number of food antigens, and toxins are capable of triggering immune responses causing inflammation, which, when unresolved, may lead to chronic conditions such as inflammatory bowel disease (IBD). It is important, therefore, to contain the gut bacteria within the lumen, control microbial load and composition, as well as ensure adequate innate and adaptive immune responses to pathogenic threats. There is growing evidence that vitamin D signaling has impacts on all these aspects of intestinal physiology, contributing to healthy enteric homeostasis. VD was first discovered as the curative agent for nutritional rickets, and its classical actions are associated with calcium absorption and bone health. However, vitamin D exhibits a number of extra-skeletal effects, particularly in innate immunity. Notably, it stimulates production of pattern recognition receptors, anti-microbial peptides, and cytokines, which are at the forefront of innate immune responses. They play a role in sensing the microbiota, in preventing excessive bacterial overgrowth, and complement the actions of vitamin D signaling in enhancing intestinal barrier function. Vitamin D also favours tolerogenic rather than inflammogenic T cell differentiation and function. Compromised innate immune function and overactive adaptive immunity, as well as defective intestinal barrier function, have been associated with IBD. Importantly, observational and intervention studies support a beneficial role of vitamin D supplementation in patients with Crohn's disease, a form of IBD. This review summarizes the effects of vitamin D signaling on barrier integrity and innate and adaptive immunity in the gut, as well as on microbial load and composition. Collectively, studies to date reveal that vitamin D signaling has widespread effects on gut homeostasis, and provide a mechanistic basis for potential therapeutic benefit of vitamin D supplementation in IBD.

Vitamin D treatment attenuates 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis but not oxazolone-induced colitis

Crohn's disease (CD) and ulcerative colitis (UC) have different immunological mechanisms, while both of them are potential targets of vitamin D treatment. In this study, we have tried to address the role of vitamin D in CD and UC using two mouse models. Mice of C57B6L were given vitamin D before the induction of colitis. Our results showed that vitamin D attenuated 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis but not oxazolone-induced colitis. Vitamin D could preserve the local histology, alleviate inflammation, suppress apoptosis, maintain tight junction function and decrease permeability. Interestingly, it has more of an effect on local structure preservation and inflammation inhibition in CD than in UC mice. Vitamin D blocked the increase of helper T-cell type 1 (Th1)- and helper T-cell type 17 (Th17)-related cytokines in TNBS-induced colitis. But the increase of helper T-cell type 2 (Th2)- and regulatory T cells (Treg)-related cytokines was augmented at the same time in oxazolone-induced colitis which counteracted each other. Our study helps elucidate the differential protective effects of vitamin D on CD and UC patients, as reported in literature.

Vitamin D machinery and metabolism in porcine adipose-derived mesenchymal stem cells

BACKGROUND

Vitamin D, a hormone once thought to have a role limited to calcium homeostasis and bone mineralization, has pleiotropic effects on different types of cells. Vitamin D receptors are reported in vascular smooth muscle cells, endothelial cells, and cardiomyocytes. Adipose-derived MSCs (ADMSCs) are multipotent cells with the capacity to differentiate into cells of different lineages. To our knowledge, the presence of vitamin D machinery on porcine ADMSCs has not yet been examined. In this study, we investigated the presence of vitamin D machinery and metabolism in ADMSCs by analyzing the expression levels of vitamin D receptor (VDR), vitamin D metabolizing enzymes (CYP24A1 and CYP27B1) after in vitro stimulation with active vitamin D, calcitriol.

METHODS AND RESULTS

ADMSCs isolated from porcine adipose tissue were characterized by positive staining for ADMSC markers, CD44, CD73, and CD90, and negative staining for macrophage marker CD11b and hematopoietic stem cell markers CD34 and CD45, and trilineage differentiation to osteocytes, chondrocytes, and adipocytes. No cytotoxicity was observed when MSCs were stimulated with 0.1-10 nM calcitriol. The ADMSCs were analyzed for mRNA and protein expression of CYP24A1, CYP27B1, and VDR by immunostaining, qPCR, and ELISA. A significant increase (p <0.01) in the mRNA expression of CYP24A1, CYP27B1, and VDR was observed after stimulation of ADMSCs with calcitriol (10 nM). The in vitro time-dependent effect of calcitriol (10 nM) on the components of vitamin D machinery in cultured MSCs was determined by qPCR. The VDR and CYP27B1 expression peaked at 3 h and CYP24A1 at 24 h, respectively. The in vitro biosynthesis of 1, 25(OH)2D3 by ADMSCs was analyzed by ELISA and Western blot. The levels of the active form of vitamin D were significantly decreased once the CYP enzymes were inhibited (p <0.01), demonstrating the ability of ADMSCs to convert inactive vitamin D into active vitamin D for cellular action.

CONCLUSIONS

Porcine ADMSCs possess vitamin D hydrolases and VDR to metabolize and respond to vitamin D. Hence, in vivo circulating 25-hydroxy vitamin D levels may have a significant role in regulating the differentiation of ADMSCs into different lineages, which might assist in stem cell-based therapy.

Protective links between vitamin D, inflammatory bowel disease and colon cancer

Vitamin D deficiency has been associated with a wide range of diseases and multiple forms of cancer including breast, colon, and prostate cancers. Relatively recent work has demonstrated vitamin D to be critical in immune function and therefore important in inflammatory diseases such as inflammatory bowel disease (IBD). Because vitamin D deficiency or insufficiency is increasingly prevalent around the world, with an estimated 30%-50% of children and adults at risk for vitamin D deficiency worldwide, it could have a significant impact on IBD. Epidemiologic studies suggest that low serum vitamin D levels are a risk factor for IBD and colon cancer, and vitamin D supplementation is associated with decreased colitis disease activity and/or alleviated symptoms. Patients diagnosed with IBD have a higher incidence of colorectal cancer than the general population, which supports the notion that inflammation plays a key role in cancer development and underscores the importance of understanding how vitamin D influences inflammation and its cancer-promoting effects. In addition to human epidemiological data, studies utilizing mouse models of colitis have shown that vitamin D is beneficial in preventing or ameliorating inflammation and clinical disease. The precise role of vitamin D on colitis is unknown; however, vitamin D regulates immune cell trafficking and differentiation, gut barrier function and antimicrobial peptide synthesis, all of which may be protective from IBD and colon cancer. Here we focus on effects of vitamin D on inflammation and inflammation-associated colon cancer and discuss the potential use of vitamin D for protection and treatment of IBD and colon cancer.

Genes and life-style factors in BELFAST nonagenarians: Nature, Nurture and Narrative

Understanding how to 'Age Longer and Age Well' is a priority for people personally, for populations globally and for government policy. Nonagenarians are the oldest members of our societies and survivors of their generation. Approximately 10 % of nonagenarians reach 90 years and beyond in good condition and seem to have a combination of both age-span and health-span. But what are the factors which help people reach their ninetieth birthday and beyond in good condition? Are they genetics, as in 'nature', or do they depend on 'nurture' and are related to environment, or are both factors inextricably intertwined within the concept of behavioural genetics? Nonagenarians have rich life experiences that can teach us much about ageing well; they are reservoirs of genetic, life-style and behavioural information which can help dissect out how to live not only longer but better. Personal family history and narrative are powerful tools that help to determine familial traits, beliefs and social behaviours and when used in parallel with new biotechnology methods inform and elaborate causality. Here we present themes and insights from personal narrative enquiry from nonagenarian participants from the Belfast Elderly Longitudinal Free-living Ageing STudy (BELFAST) about factors they consider important for good quality ageing and relate these insights to the emerging genetics and life-style evidence associated with healthy longevity.

mTOR and its tight regulation for iNKT cell development and effector function

Invariant NKT (iNKT) cells, which express the invariant Vα14Jα18 TCR that recognizes lipid antigens, have the ability to rapidly respond to agonist stimulation, producing a variety of cytokines that can shape both innate and adaptive immunity. iNKT cells have been implicated in host defense against microbial infection, in anti-tumor immunity, and a multitude of diseases such as allergies, asthma, graft versus host disease, and obesity. Emerging evidence has demonstrated crucial role for mammalian target of rapamycin (mTOR) in immune cells, including iNKT. In this review we will discuss current understanding of how mTOR and its tight regulation control iNKT cell development, effector lineage differentiation, and function.

Cell mediators of autoimmune hepatitis and their therapeutic implications

Autoimmune hepatitis is associated with interactive cell populations of the innate and adaptive immune systems, and these populations are amenable to therapeutic manipulation. The goals of this review are to describe the key cell populations implicated in autoimmune hepatitis and to identify investigational opportunities to develop cell-directed therapies for this disease. Studies cited in PubMed from 1972 to 2014 for autoimmune hepatitis, innate and adaptive immune systems, and therapeutic interventions were examined. Dendritic cells can promote immune tolerance to self-antigens, present neo-antigens that enhance the immune response, and expand the regulatory T cell population. Natural killer cells can secrete pro-inflammatory and anti-inflammatory cytokines and modulate the activity of dendritic cells and antigen-specific T lymphocytes. T helper 2 lymphocytes can inhibit the cytotoxic activities of T helper 1 lymphocytes and limit the expansion of T helper 17 lymphocytes. T helper 17 lymphocytes can promote inflammatory activity, and they can also up-regulate genes that protect against oxidative stress and hepatocyte apoptosis. Natural killer T cells can expand the regulatory T cell population; gamma delta lymphocytes can secrete interleukin-10, stimulate hepatic regeneration, and induce the apoptosis of hepatic stellate cells; and antigen-specific regulatory T cells can dampen immune cell proliferation and function. Pharmacological agents, neutralizing antibodies, and especially the adoptive transfer of antigen-specific regulatory T cells that have been freshly generated ex vivo are evolving as management strategies. The cells within the innate and adaptive immune systems are key contributors to the occurrence of autoimmune hepatitis, and they are attractive therapeutic targets.

Modulation of the immune response to respiratory viruses by vitamin D

Background: Vitamin D deficiency has been shown to be independently associated with increased risk of viral acute respiratory infection (ARI) in a number of observational studies, and meta-analysis of clinical trials of vitamin D supplementation for prevention of ARI has demonstrated protective effects. Several cellular studies have investigated the effects of vitamin D metabolites on immune responses to respiratory viruses, but syntheses of these reports are lacking. Scope: In this article, we review the literature reporting results of in vitro experiments investigating immunomodulatory actions of vitamin D metabolites in human respiratory epithelial cells infected with respiratory viruses. Key findings: Vitamin D metabolites do not consistently influence replication or clearance of rhinovirus, respiratory syncytial virus (RSV) or influenza A virus in human respiratory epithelial cell culture, although they do modulate expression and secretion of type 1 interferon, chemokines including CXCL8 and CXCL10 and pro-inflammatory cytokines, such as TNF and IL-6. Future research: More studies are needed to clarify the effects of vitamin D metabolites on respiratory virus-induced expression of cell surface markers mediating viral entry and bacterial adhesion to respiratory epithelial cells.

Vitamin D and its effects on glucose homeostasis, cardiovascular function and immune function

In recent years there has been increasing interest in the non-skeletal effects of vitamin D. It has been suggested that vitamin D deficiency may influence the development of diabetes, cardiovascular dysfunction and autoimmune diseases. This review focuses on the current knowledge of the effects of vitamin D and its deficiency on cardiovascular function, glucose homeostasis and immune function, with a particular focus on children. Although, there is good evidence to show that there is an association between vitamin D deficiency and an abnormality of the above systems, there is little evidence to show that vitamin D supplementation leads to an improvement in function, especially in childhood.

Vitamin D: Photobiological and Ecological Aspects

Vitamin D was discovered as a result of its ability to cure rickets, but recently a wide range of other functions for it in the human body has been suggested. Vitamin D is not a vitamin in the strict sense as it can be synthesised in the human body following exposure of the skin to ultraviolet radiation. Provitamin D (7-dehydrocholesterol) is converted to previtamin D which is further modified by a series of reactions to the active form, 1,25-dihydroxyvitamin D. This Chapter summarises the discovery of vitamin D and reviews the chemistry and photochemistry of its precursors, transformations and metabolites. The production of vitamin D in various human populations is described, and how to assess vitamin D status. The skeletal and non-skeletal effects of vitamin D are discussed, particularly its role in immunomodulation with consequences for protection against a variety of human diseases. The Chapter concludes with evolutionary aspects, the occurrence and role of vitamin D in the plant kingdom, biogeographical considerations, and the nonphotochemical production of vitamin D in certain plants.

Simultaneous Quantification of 25-Hydroxyvitamin D3 and 24,25-Dihydroxyvitamin D3 in Rats Shows Strong Correlations between Serum and Brain Tissue Levels

While vitamin D3 is recognized as a neuroactive steroid affecting both brain development and function, efficient analytical method in determining vitamin D3 metabolites in the brain tissue is still lacking, and the relationship of vitamin D3 status between serum and brain remains elusive. Therefore, we developed a novel analysis method by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to simultaneously quantify the concentrations of 25-hydroxyvitamin D3 (25(OH)D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) in the serum and brain of rats fed with different dose of vitamin D3. We further investigated whether variations of serum vitamin D3 metabolites could affect vitamin D3 metabolite levels in the brain. Serum and brain tissue were analyzed by HPLC-MS/MS with electrospray ionization following derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD). The method is highly sensitive, specific, and accurate to quantify 25(OH)D3 and 24,25(OH)2D3 in animal brain tissue. Vitamin D3 metabolites in brain tissue were significantly lower in rats fed with a vitamin D deficiency diet than in rats fed with high vitamin D3 diet. There was also a strong correlation of vitamin D3 metabolites in serum and brain. These results indicate that vitamin D3 status in serum affects bioavailability of vitamin D3 metabolites in the brain.

Vitamin D deficiency and adult asthma exacerbations

OBJECTIVES

There is growing evidence indicating a connection between vitamin D deficiency and the severity of asthma exacerbations. This study seeks to assess the relationship between vitamin D deficiency and the number and severity of asthma exacerbation in adults.

METHODS

A retrospective analysis was conducted in 92 patients being treated for asthma at the University of New Mexico Adult Asthma Clinic. Serum 25-hydroxyvitamin D3 levels were analyzed in adults with mild to severe persistent asthma. Using multi-variant modeling, the relationship was examined between serum vitamin D levels and the odds of asthma exacerbations ranging in severity from moderate to severe over the span of five years.

RESULTS

This study demonstrates that vitamin D sufficiency was significantly associated with a decreased total number of asthma exacerbations (incidence rate ratio [IRR]: 0.61, 95% confidence interval [CI]: 0.44-0.84, p = 0.002), decreased total severe asthma exacerbations (IRR: 0.41, 95% CI: 0.24-0.72, p = 0.002) and decreased emergency room visits (IRR: 0.42, 95% CI: 0.20-0.88, p = 0.023).

CONCLUSION

Vitamin D deficiency may be linked to the risk of severe asthma exacerbations in adults.

[Role of vitamin D in the physiopathology of neurodegenerative diseases]

The involvement of vitamin D in brain function has been discovered in the past 25 years by epidemiological and fundamental studies. Research on neurodegenerative diseases and their animal or cellular models unveiled converging lines of evidence indicating that hypovitaminosis D is not just an effect of the progression of neurodegenerative diseases, but truly an aggravating co-factor, sometimes very closely related to their physiopathology. Vitamin D is a steroid hormone capable of regulating the expression of hundreds of genes through both genetic and epigenetic mechanisms. This reflects the highly pleiotropic nature of its action in its conventional bone and phosphocalcic metabolism targets. Its role in the central nervous system and neurodegenerative diseases makes no exception to this rule. Here we focus on the identified role and mechanisms of vitamin D in multiple sclerosis, Alzheimer's disease and Parkinson's disease. The important prevalence of hypovitaminosis D under our latitudes in general and in at-risk groups in particular, its easy evaluation and correction, and the results of early clinical studies, suggest that vitamin D supplementation could usefully complement our therapeutic armory to fight these diseases.

Vitamin D regulates the gut microbiome and protects mice from dextran sodium sulfate-induced colitis

The active form of vitamin D [1,25-dihydroxycholecalciferol, 1,25(OH)2D3] and the vitamin D receptor (VDR) regulate susceptibility to experimental colitis. The effect of the bacterial microflora on the susceptibility of C57BL/6 mice to dextran sodium sulfate-induced colitis was determined. Mice that cannot produce 1,25(OH)2D3 [Cyp27b1 (Cyp) knockout (KO)], VDR KO as well as their wild-type littermates were used. Cyp KO and VDR KO mice had more bacteria from the Bacteroidetes and Proteobacteria phyla and fewer bacteria from the Firmicutes and Deferribacteres phyla in the feces compared with wild-type. In particular, there were more beneficial bacteria, including the Lactobacillaceae and Lachnospiraceae families, in feces from Cyp KO and VDR KO mice than in feces from wild-type. Helicobacteraceae family member numbers were elevated in Cyp KO compared with wild-type mice. Depletion of the gut bacterial flora using antibiotics protected mice from colitis. 1,25(OH)2D3 treatment (1.25 μg/100 g diet) of Cyp KO mice decreased colitis severity and reduced the numbers of Helicobacteraceae in the feces compared with the numbers in the feces of untreated Cyp KO mice. The mechanisms by which the dysbiosis occurs in VDR KO and Cyp KO mice included lower expression of E-cadherin on gut epithelial and immune cells and fewer tolerogenic dendritic cells that resulted in more gut inflammation in VDR and Cyp KO mice compared with wild-type mice. Increased host inflammation has been shown to provide pathogens with substrates to out-compete more beneficial bacterial species. Our data demonstrate that vitamin D regulates the gut microbiome and that 1,25(OH)2D3 or VDR deficiency results in dysbiosis, leading to greater susceptibility to injury in the gut.

Should vitamin D supplementation be a regular part of asthma care?

Vitamin D (vitD3) deficiency occurs frequently and has profound effects on health, especially asthma. This article examines how current knowledge of vitD3 actions and the worldwide distribution of vitD3 deficiency influences everyday clinical allergy practice. Within the limits of current knowledge, the article concisely explains the molecular nature of vitD3 actions, reviews key vitD3 research as it applies to clinical care, answers questions about the potential clinical impact of low vitD3 levels, and discusses use and safety of vitD3 supplements.

Vitamin D and solar ultraviolet radiation in the risk and treatment of tuberculosis

Improved understanding of the association between tuberculosis and vitamin D is needed to inform clinical practice. Vitamin D has both immunostimulatory and immunosuppressive effects relevant to human antimycobacterial responses. Ultraviolet radiation, the main source of vitamin D, also induces immunomodulation and could affect the relation between vitamin D and tuberculosis. Clinical trials of vitamin D supplementation in patients with tuberculosis have produced largely negative results, prompting the review of dosing regimens-an explanation for low 25-hydroxyvitamin D status in patients with active tuberculosis is also needed. The reporting of vitamin D deficiency needs to address assay inaccuracies, rising thresholds to define sufficiency, and scarce knowledge of the concentrations needed for optimum immune responses. Future research to measure the effect of the inflammatory setting on serum concentrations of 25-hydroxyvitamin D, at tuberculosis diagnosis and during recovery, could help to account for 25-hydroxyvitamin D changes in these concentrations in patients with tuberculosis. Studies into the role of vitamin D supplementation in latent tuberculosis justify clinical trials in this population, but pose methodological challenges. Vitamin D trials in patients with active tuberculosis should be done in well selected populations using adequate vitamin D doses, although such doses remain undefined.

Contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis

The contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis (MS) is reviewed. Among the multiple recently discovered actions of vitamin D, an immunomodulatory role has been documented in experimental autoimmune encephalomyelitis and in humans. This action in the peripheral immune system is currently the main known mechanism through which vitamin D might influence MS, but other types of actions could be involved within the central nervous system. Furthermore, vitamin D insufficiency is widespread in temperate countries and in patients with MS at the earliest stages of the disease, suggesting that the deleterious effects related to vitamin D insufficiency may be exerted in these patients. In fact, many genetic and environmental risk factors appear to interact and contribute to MS. In genetics, several human leukocyte antigen (HLA) alleles (more particularly HLA-DRB1*1501) could favour the disease whereas some others could be protective. Some of the genes involved in vitamin D metabolism (e.g. CYP27B1) also play a significant role. Furthermore, three environmental risk factors have been identified: past Epstein-Barr virus infection, vitamin D insufficiency and cigarette smoking. Interactions between genetic and environmental risk or protective factors may occur during the mother's pregnancy and could continue during childhood and adolescence and until the disease is triggered in adulthood, therefore possibly modulating the MS risk throughout the first decades of life. Furthermore, some clinical findings already strongly suggest that vitamin D status influences the relapse rate and radiological lesions in patients with MS, although the results of adequately powered randomized clinical trials using vitamin D supplementation have not yet been reported. While awaiting these incontrovertible results, which might be long in coming, patients with MS who are currently in vitamin D insufficiency should be supplemented, at least for their general health status, using moderate doses of the vitamin.

Mechanisms underlying therapeutic effects of 1,25(OH)2D3 against experimental ulcerative colitis in mice

AIM: To explore the mechanisms underlying the therapeutic effects of 1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] against experimental ulcerative colitis (UC).

METHODS: Thirty Balb/c mice were randomly assigned to groups A to E: control group, model group, low-, medium-, and high-dose intervention groups. Groups B-E were given 5% DSS solution for seven days to induce UC, while group A was given equal volume of distilled water. On days 1, 3, 5, and 7, groups C-E were intraperitoneally injected with 50, 100 and 200 ng of 1,25(OH)₂D₃, respectively. Disease activity index (DAI) and histopathological score (HPS) were calculated. The protein expression of interferon-γ (IFN-γ), interleukin (IL)-17 and IL-4 in colonic tissues was measured by immunohistochemistry.

RESULTS: Compared to the control group, the DAI and HPS were significantly higher in the model group (7.33 ± 1.03 vs 0.33 ± 0.52, 12.00 ± 0.63 vs 0.17 ± 0.41, both P < 0.01). Compared to the model group, the DAI (2.83 ± 0.40, 2.83 ± 0.75, 2.33 ± 0.52) and HPS (10.83 ± 0.98, 7.50 ± 0.84, 6.67 ± 0.52) significantly decreased in the three intervention groups (all P < 0.01). The expression of IFN-γ and IL-17 was significantly higher in the model group than in the control group (both P < 0.01), and was significantly lower in the intervention groups than in the model group (all P < 0.01). IL-4 expression was significantly lower in the model group than in the control group (P < 0.01), and was significantly higher in the intervention group than in the model group (P < 0.01).

CONCLUSION: 1,25(OH)₂D₃ can maintain local immune balance in the colonic mucosa and reduce inflammation in ulcerative colitis.

Gastric dysmotility and low serum vitamin D levels in patients with gastroparesis

Nutritional abnormalities are common in patients with gastroparesis (Gp), a disorder that may affect gastric motility and may delay emptying. The aim of this work was to identify relationships between serum nutrition markers including 25-OH vitamin D and gastric motility measures in Gp patients. We enrolled 59 consecutive gastric motility clinic patients (48 females, 11 males; mean age 44 years; 42 idiopathic; 17 diabetes mellitus) with Gp symptoms. The 25-OH vitamin D levels, for most patients slightly above the lower limit of normal (96.98 nmol/l ± 60.99), were lowest in diabetic range (DM) (75.68 nmol/l ± 34.22) vs. idiopathic (ID) (105.03 nmol/l ± 67.08) gastroparesis patients. First hour GET: one unit increase in 25-OH vitamin D level was associated 0.11% improvement (95% CI -0.22, 0.01 p=0.056) in gastric motility in all patients; this association, although marked in ID Gp patients, (-0.13, CI -0.25, -0.01 p=0.034), was not seen in DM Gp, (0.2, CI -0.45, 0.87, p=0.525). Fourth hour GET: Every unit increase of 25-OH vitamin D was associated with significant improvement in all patients, ( 0.11% CI -0.23, 0.01, p=0.053), and some weak improvement in ID group, (0.11% -0.24, 0.01, p=0.076) and absent in patients with DM (0.03, CI -0.66, 0.72, p=0.932). It is concluded that 25-OH vitamin D levels may influence gastric emptying. Underlying mechanisms for this observation might include the impact of 25-OH vitamin D on the health of the enteric nervous system. 25-OH vitamin D contributions to enteric nerve functions should be explored, particularly where autonomic nervous system comorbidities exist.

Analytical measurement of serum 25-OH-vitamin D₃, 25-OH-vitamin D₂ and their C3-epimers by LC-MS/MS in infant and pediatric specimens

OBJECTIVES

To develop a simple and sensitive LC-MS/MS procedure for quantification of serum 25-OH-vitamin D₃ (25-OH-D₃), 25-OH-vitamin D₂ (25-OH-D₂), and their C3-epimers.

METHODS

Serum 25-OH-vitamin D metabolites were extracted with MTBE and quantified by LC-MS/MS. Commercially available calibrators and QC materials were employed. The ion-transition 401.2→365.2 was monitored for 25-OH-D₃ and C3-epi-25-OH-D₃, 407.2→371.3 for d6-25-OH-D₃, 413.2→331.2 for 25-OH-D₂ and C3-epi-25-OH-D₂ and 419.2→337.1 for, d6-25-OH-D₂. As a proof-of-principle, 25-OH-D₃ and C3-epi-25-OH-D₃ were quantified in 200 pediatric subjects (0-20 years of age). Cholecalciferol supplements were examined as a potential source of C3-epimer.

RESULTS

The assay provided an LLOQ of ≤2.8 nmol/L for all 25-OH-D metabolites, with a linear response up to 400 nmol/L. The CV was <10% for 25-OH-D₂/₃ and <15% for C3-epi-25-OH-D₃. C3-epi-25-OH-D₃ was quantified in all subjects, with higher concentrations observed in infants ≤1 year of age (11.44 nmol/L vs. 4.4 nmol/L; p<0.001). Within the first year of life, 25-OH-D₃ concentrations increased linearly, while C3-epi-25-OH-D₃ concentrations remained constant. At 12 months of age, C3-epi-25-OH-D₃ concentration dropped by almost 50% (11.4 nmol/L in infants ≤1year of age vs. 5.4 nmol/L in infants 1-2years of age; p<0.001). Liquid vitamin D₃ supplements did not contain appreciable amounts of C3-epi-D₃.

CONCLUSIONS

The proposed LC-MS/MS procedure is suitable for quantifying 25-OH-D₃ metabolites. Although the C3-epimer is present in all pediatric subjects, it is significantly elevated in individuals ≤1 year of age and drops at 12 months of age. Oral vitamin D supplements are unlikely to be a significant source of C3-vitamin D epimer.

Kynurenines in the CNS: recent advances and new questions

Various pathologies of the central nervous system (CNS) are accompanied by alterations in tryptophan metabolism. The main metabolic route of tryptophan degradation is the kynurenine pathway; its metabolites are responsible for a broad spectrum of effects, including the endogenous regulation of neuronal excitability and the initiation of immune tolerance. This Review highlights the involvement of the kynurenine system in the pathology of neurodegenerative disorders, pain syndromes and autoimmune diseases through a detailed discussion of its potential implications in Huntington's disease, migraine and multiple sclerosis. The most effective preclinical drug candidates are discussed and attention is paid to currently under-investigated roles of the kynurenine pathway in the CNS, where modulation of kynurenine metabolism might be of therapeutic value.

The influence of nutritional factors on the prognosis of multiple sclerosis

The effect of nutrition and dietary supplements on the course of multiple sclerosis (MS) is a topic of great interest to both patients and clinicians. In particular, vitamin D status has been shown to influence both the incidence and the course of MS. High vitamin D levels are probably protective against the development of MS, although the efficacy of vitamin D supplementation in slowing progression of MS remains to be established. The influence of polyunsaturated fatty acids (PUFAs) on the development and course of MS has also long been under investigation. Small clinical trials suggest a modest reduction in the severity and duration of relapses in patients with MS receiving PUFA supplements. Other nutritional factors have been evaluated for their effect on MS disease progression, including milk proteins, gluten, probiotics, antioxidants (uric acid, vitamins A, C and E, lipoic acid), polyphenols, Ginkgo biloba extracts and curcumin. However, further studies are needed to evaluate the effects of these dietary components on the relapse rate and progression of MS. This Review gives an overview of the literature on the nutritional factors most commonly implicated as having an effect on MS and discusses the biological rationale that is thought to underlie their influence.

Prenatal vitamin D deficiency induces an early and more severe experimental autoimmune encephalomyelitis in the second generation

In a previous study, we demonstrated that mouse adult F(1) offspring, exposed to a vitamin D deficiency during pregnancy, developed a less severe and delayed Experimental Autoimmune Encephalomyelitis (EAE), when compared with control offspring. We then wondered whether a similar response was observed in the subsequent generation. To answer this question, we assessed F(2) females whose F(1) parents (males or females) were vitamin D-deprived when developing in the uterus of F(0) females. Unexpectedly, we observed that the vitamin D deficiency affecting the F(0) pregnant mice induced a precocious and more severe EAE in the F(2) generation. This paradoxical finding led us to assess its implications for the epidemiology of Multiple Sclerosis (MS) in humans. Using the REFGENSEP database for MS trios (the patient and his/her parents), we collected the parents' dates of birth and assessed a potential season of birth effect that could potentially be indicative of the vitamin D status of the pregnant grandmothers. A trend for a reduced number of births in the Fall for the parents of MS patients was observed but statistical significance was not reached. Further well powered studies are warranted to validate the latter finding.