Vitamin D and multiple sclerosis: Potential pathophysiological role and clinical implications

The protective role of interaction between vitamin D, sex hormones and calcium in multiple sclerosis

Multiple sclerosis (MS) is a neurological disorder that causes disability and paralysis, especially among young adults. Although interactions of several factors, such as viral infections, autoimmunity, genetic and environmental factors, performance a role in the beginning and progression of the disease, the exact cause of MS is unknown to date. Different immune cells such as Th1 and Th17 play an impressive role in the immunopathogenesis of MS, while, regulatory cells such as Th2 and Treg diminish the severity of the illness. Sex hormones have a vital role in many autoimmune disorders, including multiple sclerosis. Testosterone, estrogen and progesterone have various roles in the progress of MS, which higher prevalence of disease in women and more severe in men reveals the importance of sex hormones' role in this disease. Vitamin D after chemical changes in the body, as an active hormone called calcitriol, plays an important role in regulating immune responses and improves MS by modulating the immune system. The optimum level of calcium in the body with vitamin D modulates immune responses and calcium as an essential ion in the body plays a key role in the treatment of autoimmune diseases. The interaction between vitamin D and sex hormones has protective and therapeutic effects against MS and functional synergy between estrogen and calcitriol occurs in disease recovery. Moreover, vitamin D and calcium interact with each other to regulate the immune system and shift them to anti-inflammatory responses.

Adrenoceptors as potential target for add-on immunomodulatory therapy in multiple sclerosis

This review summarizes recent findings related to the role of the sympathetic nervous system (SNS) in pathogenesis of multiple sclerosis (MS) and its commonly used experimental model - experimental autoimmune encephalomyelitis (EAE). They indicate that noradrenaline, the key end-point mediator of the SNS, acting through β-adrenoceptor, has a contributory role in the early stages of MS/EAE development. This stage is characterized by the SNS hyperactivity (increased release of noradrenaline) reflecting the net effect of different factors, such as the disease-associated inflammation, stress, vitamin D hypovitaminosis, Epstein-Barr virus infection and dysbiosis. Thus, the administration of propranolol, a non-selective β-adrenoceptor blocker, readily crossing the blood-brain barrier, to experimental rats before the autoimmune challenge and in the early (preclinical/prodromal) phase of the disease mitigates EAE severity. This phenomenon has been ascribed to the alleviation of neuroinflammation (due to attenuation of primarily microglial activation/proinflammatory functions) and the diminution of the magnitude of the primary CD4+ T-cell autoimmune response (the effect associated with impaired autoantigen uptake by antigen presenting cells and their migration into draining lymph nodes). The former is partly related to breaking of the catecholamine-dependent self-amplifying microglial feed-forward loop and the positive feedback loop between microglia and the SNS, leading to down-regulation of the SNS hyperactivity and its enhancing influence on microglial activation/proinflammatory functions and the magnitude of autoimmune response. The effects of propranolol are shown to be more prominent in male EAE animals, the phenomenon important as males (like men) are likely to develop clinically more severe disease. Thus, these findings could serve as a firm scientific background for formulation of a new sex-specific immune-intervention strategy for the early phases of MS (characterized by the SNS hyperactivity) exploiting anti-(neuro)inflammatory and immunomodulatory properties of propranolol and other relatively cheap and safe adrenergic drugs with similar therapeutic profile.

Association of Multiple Sclerosis Prevalence With Sociodemographic, Health Systems, and Lifestyle Factors on a National and Regional Level

BACKGROUND AND OBJECTIVES

Multiple sclerosis (MS) prevalence varies widely by country and world region, variation that is often attributed to latitude and its association with vitamin D exposure. Given that increasing latitude is also associated with higher national wealth, this study investigated associations between MS prevalence and other factors driving regional differences, with a focus on sociodemographic, health systems, and lifestyle factors on a national and regional level.

METHODS

Using data from multilateral organizations and scientific literature, an ecological study was conducted to evaluate associations between age- and sex-adjusted MS prevalence and prespecified sociodemographic (gross domestic product [GDP] per capita and gross national income [GNI] per capita), health systems (current health expenditure per capita and by percentage of GDP, universal health coverage [UHC] index, and medical doctors per capita), neurology-specific (MRI unit density and neurologists per capita), and lifestyle (obesity and tobacco use) factors. National, regional, and income-stratified data were aggregated and employed in relevant univariable and multivariable regression models. Stepwise variable selection techniques identified independent predictors of MS prevalence.

RESULTS

Univariable regression analyses showed significant associations at the national level for all investigated factors, except obesity prevalence and tobacco use. Latitude was significantly associated with MS prevalence in all world regions (β = 0.16-2.16), whereas the UHC index was significantly associated in 5 of 6 world regions (β = 0.18-3.17). MS prevalence was significantly associated with all factors except lifestyle factors and MRI unit density in high-income countries, but no associations were observed in low-income countries. Latitude was associated with MS prevalence for all income strata except low-income countries (β = 0.55-1.62). In multivariable analyses, current health expenditure per capita (β = 0.083, 95% CI 0.048-0.12, p < 0.01) and latitude (β = 1.05, 95% CI 0.63-1.47, p < 0.01) remained significantly associated with MS prevalence.

DISCUSSION

Health expenditure per capita is strongly associated with national MS prevalence, suggesting that theories that attribute variations in MS prevalence primarily to latitude effects on vitamin D are incomplete. Health care access significantly contributes to the global variations in MS prevalence, especially since national wealth rises with latitude and likely results in significant underestimation of MS prevalence in countries with lower health expenditure.

Early-Onset Multiple Sclerosis With Frequent Relapses: A Challenging Diagnosis With a Less Favorable Prognosis

Pediatric multiple sclerosis (MS) is a rare demyelinating disease of the brain, spinal cord, and optic nerve caused by immune modulators mediating against the neuronal axons of the central nervous system. MS is usually characterized by a series of neurological events, without any features of encephalopathy, separated in time and space. The complications arise from the permanent degeneration of the nerves. This condition can be diagnosed based on International Pediatric Multiple Sclerosis Study Group diagnostic criteria, and there is no definitive treatment for MS. We report the case of a male child who was diagnosed with MS at the age of six years when he presented with right hemiparesis and visual impairment. Subsequently, he had multiple relapses with varied neurological presentations, and each relapse was treated with methylprednisolone.

A Review of Various Antioxidant Compounds and their Potential Utility as Complementary Therapy in Multiple Sclerosis

Multiple sclerosis (MS) is a complex disease of the central nervous system (CNS). The etiology of this multifactorial disease has not been clearly defined. Conventional medical treatment of MS has progressed, but is still based on symptomatic treatment. One of the key factors in the pathogenesis of MS is oxidative stress, enhancing inflammation and neurodegeneration. In MS, both reactive oxygen and nitrogen species are formed in the CNS mainly by activated macrophages and microglia structures, which can lead to demyelination and axon disruption. The course of MS is associated with the secretion of many inflammatory and oxidative stress mediators, including cytokines (IL-1b, IL-6, IL-17, TNF-α, INF-γ) and chemokines (MIP-1a, MCP-1, IP10). The early stage of MS (RRMS) lasts about 10 years, and is dominated by inflammatory processes, whereas the chronic stage is associated with neurodegenerative axon and neuron loss. Since oxidative damage has been known to be involved in inflammatory and autoimmune-mediated processes, antioxidant therapy could contribute to the reduction or even prevention of the progression of MS. Further research is needed in order to establish new aims for novel treatment and provide possible benefits to MS patients. The present review examines the roles of oxidative stress and non-pharmacological anti-oxidative therapies in MS.

Latitude, Vitamin D, Melatonin, and Gut Microbiota Act in Concert to Initiate Multiple Sclerosis: A New Mechanistic Pathway

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). While the etiology of MS is still largely unknown, scientists believe that the interaction of several endogenous and exogenous factors may be involved in this disease. Epidemiologists have seen an increased prevalence of MS in countries at high latitudes, where the sunlight is limited and where the populations have vitamin D deficiency and high melatonin levels. Although the functions and synthesis of vitamin D and melatonin are contrary to each other, both are involved in the immune system. While melatonin synthesis is affected by light, vitamin D deficiency may be involved in melatonin secretion. On the other hand, vitamin D deficiency reduces intestinal calcium absorption leading to gut stasis and subsequently increasing gut permeability. The latter allows gut microbiota to transfer more endotoxins such as lipopolysaccharides (LPS) into the blood. LPS stimulates the production of inflammatory cytokines within the CNS, especially the pineal gland. This review summarizes the current findings on the correlation between latitude, sunlight and vitamin D, and details their effects on intestinal calcium absorption, gut microbiota and neuroinflammatory mediators in MS. We also propose a new mechanistic pathway for the initiation of MS.

Ability of vitamin D to reduce inflammation in adults without acute illness

In vitro studies and some clinical studies suggest that vitamin D plays an important role in reducing inflammation. The objective of this review was to examine recent evidence that vitamin D status influences the level of inflammation in adults without acute illness or injury. Five large cross-sectional studies and two randomized controlled trials are the focus of this review. Associations between 25-hydroxyvitamin D (25OHD) and inflammation markers are significant and inverse in study populations with low 25OHD levels (<21 ng/mL). They are also inverse in adults with relatively high inflammation levels. These associations in the few available randomized controlled vitamin D intervention trials have been null; this may be because they were not examined in populations with sufficiently low levels of 25OHD or high levels of inflammation.

New insights into an autoimmune mechanism, pharmacological treatment and relationship between multiple sclerosis and inflammatory bowel disease

Inflammatory bowel disease (IBD) and multiple sclerosis (MS) are autoimmune diseases with a close relationship to their disease pattern and immunologic cascade with considerable morbidity and mortality. This article provides insight of why tumor necrosis factor blockers couldn't work in multiple sclerosis and why interferon-beta doesn't work in inflammatory bowel disease. In this article, we provide a detailed review of the linkage and potential interchangeable medication between IBD and MS in addition to Natalizumab, Trichuris suis egg therapy and vitamin D. Different treatment strategies may have potential in treating both diseases in the future.