Vitamin D and multiple sclerosis

Vitamin D insufficiency

Vitamin D deficiency, which classically manifests as bone disease (either rickets or osteomalacia), is characterized by impaired bone mineralization. More recently, the term vitamin D insufficiency has been used to describe low levels of serum 25-hydroxyvitamin D that may be associated with other disease outcomes. Reliance on a single cutoff value to define vitamin D deficiency or insufficiency is problematic because of the wide individual variability of the functional effects of vitamin D and interaction with calcium intakes. In adults, vitamin D supplementation reduces the risk of fractures and falls. The evidence for other purported beneficial effects of vitamin D is primarily based on observational studies. We selected studies with the strongest level of evidence for clinical decision making related to vitamin D and health outcomes from our personal libraries of the vitamin D literature and from a search of the PubMed database using the term vitamin D in combination with the following terms related to the potential nonskeletal benefits of vitamin D: mortality, cardiovascular, diabetes mellitus, cancer, multiple sclerosis, allergy, asthma, infection, depression, psychiatric, and pain. Conclusive demonstration of these benefits awaits the outcome of controlled clinical trials.

Vitamin D as a T-cell modulator in multiple sclerosis

Vitamin D is a potent immune modulator, keeping the T-cell compartment in a more tolerogenic state. Multiple sclerosis (MS), a disease in which an autoreactive T-cell response contributes to inflammation in the central nervous system, has been associated with vitamin D deficiency. The effects of vitamin D on the immune system are believed to be an important driver of this association. In this chapter, we elaborate on vitamin D as a modulator of the T-cell response. This discussion will be placed in the perspective of MS as a T-cell-mediated disease and in the perspective of the numerous association studies on vitamin D deficiency and multiple health outcomes. We conclude that there is a firm experimental and epidemiological basis supporting the model of vitamin D as a physiological immune modulator, on which intervention studies assessing clinical and immunological outcome measures should be designed.

Safety and T cell modulating effects of high dose vitamin D3 supplementation in multiple sclerosis

BACKGROUND

A poor vitamin D status has been associated with a high disease activity of multiple sclerosis (MS). Recently, we described associations between vitamin D status and peripheral T cell characteristics in relapsing remitting MS (RRMS) patients. In the present study, we studied the effects of high dose vitamin D3 supplementation on safety and T cell related outcome measures.

METHODOLOGY/PRINCIPAL FINDINGS

Fifteen RRMS patients were supplemented with 20,000 IU/d vitamin D3 for 12 weeks. Vitamin D and calcium metabolism were carefully monitored, and T cell characteristics were studied by flowcytometry. All patients finished the protocol without side-effects, hypercalcaemia, or hypercalciuria. The median vitamin D status increased from 50 nmol/L (31-175) at week 0 to 380 nmol/L (151-535) at week 12 (P<0.001). During the study, 1 patient experienced an exacerbation of MS and was censored from the T cell analysis. The proportions of (naïve and memory) CD4+ Tregs remained unaffected. Although Treg suppressive function improved in several subjects, this effect was not significant in the total cohort (P=0.143). An increased proportion of IL-10+ CD4+ T cells was found after supplementation (P=0.021). Additionally, a decrease of the ratio between IFN-γ+ and IL-4+ CD4+ T cells was observed (P=0.035).

CONCLUSION/SIGNIFICANCE

Twelve week supplementation of high dose vitamin D3 in RRMS patients was well tolerated and did not induce decompensation of calcium metabolism. The skewing towards an anti-inflammatory cytokine profile supports the evidence on vitamin D as an immune-modulator, and may be used as outcome measure for upcoming randomized placebo-controlled trials.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00940719.

Heterogeneity in multiple sclerosis: scratching the surface of a complex disease

Multiple Sclerosis (MS) is the most common demyelinating disease of the central nervous system. Although the etiology and the pathogenesis of MS has been extensively investigated, no single pathway, reliable biomarker, diagnostic test, or specific treatment have yet been identified for all MS patients. One of the reasons behind this failure is likely to be the wide heterogeneity observed within the MS population. The clinical course of MS is highly variable and includes several subcategories and variants. Moreover, apart from the well-established association with the HLA-class II DRB1*15:01 allele, other genetic variants have been shown to vary significantly across different populations and individuals. Finally both pathological and immunological studies suggest that different pathways may be active in different MS patients. We conclude that these "MS subtypes" should still be considered as part of the same disease but hypothesize that spatiotemporal effects of genetic and environmental agents differentially influence MS course. These considerations are extremely relevant, as outcome prediction and personalised medicine represent the central aim of modern research.

Emerging concepts in pediatric-onset multiple sclerosis and related disorders

PURPOSE OF REVIEW

Pediatric-onset multiple sclerosis (MS) is increasingly recognized. Conversely, MS diagnosis in the pediatric population continues to be challenging, particularly in the youngest group of patients. An interesting amount of data has been recently published concerning immunopathogenesis, environmental factors, diagnosis, and treatment of MS in pediatric patients.

RECENT FINDINGS

Recent studies have demonstrated that brain MRI criteria may distinguish MS from acute disseminated encephalomyelitis, and from nondemyelinating disorders in children. The presence of native myelin oligodendrocyte glycoprotein antibodies strongly correlates with a particular pediatric MS phenotype. Vitamin D, Epstein-Barr virus infection, and cigarette smoke are risk factors likely to act at specific stages during life. Diffuse tissue damage was confirmed in normal-appearing white matter at early stages of disease in children with MS, pointing to the need for early treatment interventions. The cognitive involvement of MS in children is progressive.

SUMMARY

Pediatric-onset MS needs a prompt identification and early treatment. Further multinational research studies are still necessary to advance on genetic, immunologic, and imaging features on the initial and ongoing aspects of this disorder in the pediatric population.

Transgenic mouse models of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease affecting the central nervous system (CNS) and a frequent cause of neurological disability in young adults. Multifocal inflammatory lesions in the CNS white matter, demyelination, oligodendrocyte loss, axonal damage, as well as astrogliosis represent the histological hallmarks of the disease. These pathological features of MS can be mimicked, at least in part, using animal models. This review discusses the current concepts of the immune effector mechanisms driving CNS demyelination in murine models. It highlights the fundamental contribution of transgenesis in identifying the mediators and mechanisms involved in the pathophysiology of MS models.

Rediscovering vitamin D

Over the past 2 years there has been a radical change in standard clinical practice with respect to vitamin D. As a result of a growing body of knowledgeable physicians are assessing the vitamin D nutritional status of their patients and prescribing aggressive repletion regimens of a vitamin D supplement. The present paper summarizes some basic information about this essential nutrient and reviews some of the more recent data implicating vitamin D deficiency in disease etiology with an emphasis on cardiovascular disease and cancer. Finally a rational approach to the dosing of vitamin D in different patient populations is provided.

Vitamin d and multiple sclerosis: correlation, causality, and controversy

The last years, many studies reported associations between correlates of vitamin D exposure and several correlates of multiple sclerosis (MS) disease activity. This review discusses studies on vitamin D status, Expanded Disability Status Scale (EDSS) score, and relapse activity of MS. Furthermore, several considerations for intervention studies on vitamin D supplementation in MS are provided.

Cytokine patterns after therapy with Avonex®, Rebif®, Betaferon® and CinnoVex™ in relapsing–remitting multiple sclerosis in Iranian patients

Aim: Several lines of evidence exist which suggest that changes in the expression of circulating cytokines are linked to the development or reoccurrence of multiple sclerosis (MS). This study aimed to evaluate the serum levels of relevant cytokines after therapy with IFN-β formulations in MS patients. Materials & methods: In this study, blood samples were collected from 70 MS patients undergoing four different types of IFN-β formulation treatment and 100 healthy controls. After 24 months of treatment, the serum levels of IL-17A, IL-12, IFN-γ and IL-10 in patients and healthy controls were analyzed by ELISA. Results: Our results demonstrated that serum levels of IL-17A were significantly higher in patients treated with CinnoVex™ and Avonex® when compared with healthy controls. Serum levels of IL-10 were significantly decreased after therapy with CinnoVex, whereas serum levels of IFN-β were elevated. No difference in serum levels of IL-12 were detected between patients and controls. Conclusion: Results of our study suggest that CinnoVex and Avonex modulate the immune system less than Rebif® and Betaferon® in MS patients, and an elevated dose of CinnoVex and Avonex may be required for better regulation of the immune system in MS patients.

Gender differences in 1,25 dihydroxyvitamin D3 immunomodulatory effects in multiple sclerosis patients and healthy subjects

Vitamin D(3) is best known as a calcium homeostasis modulator; however, it also has immune-modulating potential. In this study, we demonstrated that immunomodulatory effects of vitamin D(3) are significantly stronger in females than in males in multiple sclerosis patients, as well as in healthy subjects. Inhibition of self-reactive T cell proliferation and reduction in IFN-γ- and IL-17-secreting cell numbers were considerably greater in females. Furthermore, the increase in IL-10-secreting and CD4(+)CD25(+)FoxP3(+) regulatory T cell numbers were also greater in females. In parallel with these findings, female subjects had fewer CYP24A1 transcripts encoding the 1,25-dihydroxyvitamin D(3)-inactivating enzyme, as well as greater binding and internalization of vitamin D(3)-binding protein, a transporter for vitamin D(3) and its metabolites. These gender-based disparities lead to the accumulation of vitamin D(3) and its metabolites in target cells from female subjects and result in a more potent anti-inflammatory effect. Interestingly, 17-β estradiol reproduced these effects on self-reactive T cells and macrophages from male subjects, suggesting a functional synergy between 1,25-dihydroxyvitamin D(3) and 17-β estradiol, mediated through estrogen receptor α. Collectively, these results demonstrate estrogen-promoted differences in vitamin D(3) metabolism, suggesting a greater protective effect of vitamin D(3)-based therapeutic strategies in women.

Is hypovitaminosis D one of the environmental risk factors for multiple sclerosis?

The role of hypovitaminosis D as a possible risk factor for multiple sclerosis is reviewed. First, it is emphasized that hypovitaminosis D could be only one of the risk factors for multiple sclerosis and that numerous other environmental and genetic risk factors appear to interact and combine to trigger the disease. Secondly, the classical physiological notions about vitamin D have recently been challenged and the main new findings are summarized. This vitamin could have an important immunological role involving a number of organs and pathologies, including autoimmune diseases and multiple sclerosis. Furthermore, human requirements for this vitamin are much higher than previously thought, and in medium- or high-latitude countries, they might not be met in the majority of the general population due to a lack of sunshine and an increasingly urbanized lifestyle. Thereafter, the different types of studies that have helped to implicate hypovitaminosis D as a risk factor for multiple sclerosis are reviewed. In experimental autoimmune encephalomyelitis, vitamin D has been shown to play a significant immunological role. Diverse epidemiological studies suggest that a direct chain of causality exists in the general population between latitude, exposure to the sun, vitamin D status and the risk of multiple sclerosis. New epidemiological analyses from France support the existence of this chain of links. Recently reported immunological findings in patients with multiple sclerosis have consistently shown that vitamin D significantly influences regulatory T lymphocyte cells, whose role is well known in the pathogenesis of the disease. Lastly, in a number of studies on serum levels of vitamin D in multiple sclerosis, an insufficiency was observed in the great majority of patients, including at the earliest stages of the disease. The questionable specificity and significance of such results is detailed here. Based on a final global analysis of the cumulative significance of these different types of findings, it would appear likely that hypovitaminosis D is one of the risk factors for multiple sclerosis.

Multiple sclerosis: risk factors, prodromes, and potential causal pathways

Multiple sclerosis (MS) is a common, complex neurological disease. The precise aetiology of MS is not yet known, although epidemiological data indicate that both genetic and environmental factors are important. The evidence that the environment acts long before MS becomes clinically evident is well established and suggests the existence of a prodromal phase for the disease. The increasing incidence of MS emphasises the need for strategies to prevent this chronic disorder, and the possibility of a prodrome indicates a window of opportunity to potentially reverse early disease processes before clinical disease becomes evident. Studying a prodrome requires techniques other than clinical observation such as monitoring endophenotypes that result from associated risk factors. However, our current knowledge of causal pathways and endophenotypes in MS is limited. Identifying and studying individuals with a high risk of developing the disease provides a powerful opportunity to understand the MS causal cascade and is highly relevant to strategies that are aimed at preventing this debilitating disease.

An ecological study of cancer incidence and mortality rates in France with respect to latitude, an index for vitamin D production

France has unexplained large latitudinal variations in cancer incidence and mortality rates. Studies of cancer rate variations in several other countries, as well as in multicountry studies, have explained such variations primarily in terms of gradients in solar ultraviolet-B (UVB) doses and vitamin D production. To investigate this possibility in France, I obtained data on cancer incidence and mortality rates for 21 continental regions and used this information in regression analyses with respect to latitude. This study also used dietary data. Significant positive correlations with latitude emerged for breast, colorectal, esophageal (males), lung (males), prostate, both uterine cervix and uterine corpus, all and all less lung cancer. Although correlations with latitude were similar for males and females, the regression variance for all and all less lung cancer was about twice as high for males than for females. Lung cancer incidence and mortality rates for females had little latitudinal gradient, indicating that smoking may have also contributed to the latitudinal gradients for males. On the basis of the available dietary factor, micro- and macronutrient data, dietary differences do not significantly affect geographical variation in cancer rates. These results are consistent with solar UVB's reducing the risk of cancer through production of vitamin D. In the context of serum 25-hydroxyvitamin D level-cancer incidence relations, cancer rates could be reduced significantly in France if everyone obtained an additional 1,000 IU/day of vitamin D. Many other benefits of vitamin D exist as well.