Intermittent Fasting Confers Protection in CNS Autoimmunity by Altering the Gut Microbiota

Multiple sclerosis (MS) is more common in western countries with diet being a potential contributing factor. Here we show that intermittent fasting (IF) ameliorated clinical course and pathology of the MS model, experimental autoimmune encephalomyelitis (EAE). IF led to increased gut bacteria richness, enrichment of the Lactobacillaceae, Bacteroidaceae, and Prevotellaceae families and enhanced antioxidative microbial metabolic pathways. IF altered T cells in the gut with a reduction of IL-17 producing T cells and an increase in regulatory T cells. Fecal microbiome transplantation from mice on IF ameliorated EAE in immunized recipient mice on a normal diet, suggesting that IF effects are at least partially mediated by the gut flora. In a pilot clinical trial in MS patients, intermittent energy restriction altered blood adipokines and the gut flora resembling protective changes observed in mice. In conclusion, IF has potent immunomodulatory effects that are at least partially mediated by the gut microbiome.

Link between overweight/obese in children and youngsters and occurrence of multiple sclerosis

BACKGROUND/AIMS

The prevalence of overweight/obesity is a major problem in the world, and the number of MS cases is increasing. This literature study examines the relationship between overweight/obesity in children and adolescents and later occurrence of MS.

METHOD

This is a complete literature survey. The search database is primarily Pubmed using MeSH terms "multiple sclerosis", "obesity", and "overweight", and text words not to restrict searches.

RESULTS

All included studies show a link between being overweight/obese and the presence of MS among people below 20 years of age. The relation is especially true for young girls. The same relation in boys is not significant.

CONCLUSION

The literature survey convincingly revealed a link between young overweight/obese and occurrence of MS, in particular for girls. There is a need for more and larger studies to investigate the molecular mechanisms that link obesity and MS.

Symptom Management and Lifestyle Modifications in Multiple Sclerosis

PURPOSE OF REVIEW

This article reviews the rationale and approach to symptom management and lifestyle modifications in multiple sclerosis (MS).

RECENT FINDINGS

MS symptoms are important to treat because they affect quality of life and daily activity. Appreciation of cluster symptoms (where one symptom contributes to another), changes over time, and multimodality therapeutic approaches are guiding optimized symptom management. Equally important are lifestyle modifications that enhance central nervous system reserve and function. These modifications are the foundation for a health maintenance, wellness, and vascular risk factor control program.

SUMMARY

Symptom management and lifestyle modifications are important therapeutic targets to improve the lives of patients with MS.

Environmental factors and their interactions with risk genotypes in MS susceptibility

PURPOSE OF REVIEW

The area of multiple sclerosis (MS) epidemiology has expanded during the last few years. Established lifestyle and environmental factors influencing MS risk are Epstein-Barr virus infection, sun exposure/vitamin D, and smoking. We review these factors and a series of other potential candidates implicated in the pathogenesis of MS and how environmental factors interact with genetic susceptibility with regard to disease risk.

RECENT FINDINGS

On top of established MS-associated factors, there is now strong evidence for influence of adolescent obesity, exposure to organic solvents and shift work, all demonstrating increased risk of disease. Other factors, such as nicotine, alcohol, and high coffee consumption are associated with decreased MS risk. A number of lifestyle/environmental factors, including smoking and obesity, seem to interact with MS risk human leukocyte antigen genes, conferring much stronger effects on disease risk among those exposed to both factors. Furthermore, an interaction between two environmental factors, obesity and infectious mononucleosis, with regard to MS risk, has been demonstrated in two independent studies.

SUMMARY

MS is a complex disease for which both genetic susceptibility and lifestyle/environmental factors are important, and where the latter may be of great importance. Lifestyle and environmental factors can often be modified and may denote pathogenic pathways.

Dietary Interventions and Multiple Sclerosis

Multiple Sclerosis (MS) is a chronic, disabling neurologic disease that has its onset in young adulthood. While the knowledge about underlying pathogenesis of MS has improved significantly over the last few decades, the exact cause still eludes us. Despite the availability of several United States Food and Drug Administration-approved disease-modifying therapies (DMT) for MS in the last two decades, the disease remains disabling for many. DMT use is limited by its partial effectiveness, significant side effects in many cases, and high cost that leads people with MS (PwMS) to look for alternative management options. Dietary intervention as a possible mode to help MS seems very appealing to PwMS; however, scientific data supporting this notion remains sparse. New information on the role of various non-MS health factors, especially vascular disease risk factors such as hypertension, hyperlipidemia, salt intake, and obesity, that may play a role in MS pathogenesis appears very intriguing as it may partly explain the heterogeneity seen in MS activity and disability. This review will highlight the emerging information on various dietary approaches that may affect MS and their possible underlying mechanism.

Vitamin D and multiple sclerosis: An update

The most recent findings linking exposure to sun and vitamin D insufficiency to multiple sclerosis (MS) are reviewed. Due to insufficient sunshine and changing lifestyles, hypovitaminosis D is widespread in temperate countries. Numerous epidemiological studies have strongly suggested that sunshine and vitamin D insufficiency contributes to MS risk in these countries. Moreover, several large genetic studies in MS patients have recently stated unequivocally that diverse abnormalities involving vitamin D metabolism are related to the risk of the disease. The important implications of such results are discussed here. Then, the interactions of hypovitaminosis D with the other genetic and environmental protective and risk factors, such as the allele HLA DRB1*1501, Epstein-Barr virus infection, obesity, smoking and sexual hormones, are summarized. Vitamin D insufficiency and sufficiency could be a risk and a protective factor, respectively, among many other factors possibly continuously modulating the global MS risk from the mother's pregnancy to the triggering of MS in adulthood. However, many interactions between these different factors occur more particularly between conception and the end of adolescence, which corresponds to the period of maturation of the immune system and thymus and may be related to the dysimmune nature of the disease. The main mechanisms of action of vitamin D in MS appear to be immunomodulatory, involving the various categories of T and B lymphocytes in the general immune system, but neuroprotector and neurotrophic mechanisms could also be exerted at the central nervous system level. Furthermore, several controlled immunological studies performed in MS patients have recently confirmed that vitamin D supplementation has multiple beneficial immunomodulatory effects. However, there is still an enduring absence of major conclusive randomized clinical trials testing vitamin D supplementation in MS patients because of the quasi-insurmountable practical difficulties that exist nowadays in conducting and completing over several years such studies involving the use of a vitamin. Nevertheless, it should be noted that similar robust statistical models used in five different association studies have already predicted a favorable vitamin D effect reducing relapses by 50-70%. If there is now little doubt that vitamin D exerts a beneficial action on the inflammatory component of MS, the results are as yet much less clear for the progressive degenerative component. Lastly, until more information becomes available, vitamin D supplementation of MS patients, using a moderate physiological dose essentially correcting their vitamin insufficiency, is recommended.

Body size and physical exercise, and the risk of multiple sclerosis

BACKGROUND

Whether large body size increases multiple sclerosis (MS) risk in men is not well understood. Concurrently, physical exercise could be an independent protective factor.

OBJECTIVE

To prospectively investigate the association between body mass index (BMI) and aerobic fitness, indicators of body size and exercise, and MS risk in men.

METHODS

We performed a population-based nested case-control study within the historical cohort of all Norwegian men, born in 1950-1975, undergoing mandatory conscription at the age of 19 years. 1016 cases were identified through linkage to the Norwegian MS registry, while 19,230 controls were randomly selected from the cohort. We estimated the effect of BMI and fitness at conscription on MS risk using Cox regression.

RESULTS

Higher BMI (≥25 vs 18.5-<25 kg/m²) was significantly associated with increased MS risk (adjusted relative risk (RR_adj) = 1.36, 95% confidence interval (CI): 1.05-1.76). We also found a significant inverse association between aerobic fitness (high vs low) and MS risk independent of BMI (RR_adj = 0.69, 95% CI: 0.55-0.88, p-trend = 0.003), remaining similar when men with MS onset within 10 years from conscription were excluded ( p-trend = 0.03).

CONCLUSION

These findings add weight to evidence linking being overweight to an increased MS risk in men. Furthermore, they suggest that exercise may be an additional modifiable protective factor for MS.

Causal Effect of Genetic Variants Associated With Body Mass Index on Multiple Sclerosis Susceptibility

Multiple sclerosis (MS) is an autoimmune disease with both genetic and environmental risk factors. Recent studies indicate that childhood and adolescent obesity double the risk of MS, but this association may reflect unmeasured confounders rather than causal effects of obesity. We used separate-sample Mendelian randomization to estimate the causal effect of body mass index (BMI) on susceptibility to MS. Using data from non-Hispanic white members of the Kaiser Permanente Medical Care Plan of Northern California (KPNC) (2006-2014; 1,104 cases of MS and 10,536 controls) and a replication data set from Sweden (the Epidemiological Investigation of MS (EIMS) and the Genes and Environment in MS (GEMS) studies, 2005-2013; 5,133 MS cases and 4,718 controls), we constructed a weighted genetic risk score using 97 variants previously established to predict BMI. Results were adjusted for birth year, sex, education, smoking status, ancestry, and genetic predictors of MS. Estimates in KPNC and Swedish data sets suggested that higher genetically induced BMI predicted greater susceptibility to MS (odds ratio = 1.13, 95% confidence interval: 1.04, 1.22 for the KPNC sample; odds ratio = 1.09, 95% confidence interval: 1.03, 1.15 for the Swedish sample). Although the mechanism remains unclear, to our knowledge, these findings support a causal effect of increased BMI on susceptibility to MS for the first time, and they suggest a role for inflammatory pathways that characterize both obesity and the MS disease process.

Environmental modifiable risk factors for multiple sclerosis: Report from the 2016 ECTRIMS focused workshop

Multiple sclerosis (MS) is an inflammatory and neurodegenerative demyelinating disease of the central nervous system (CNS), most likely autoimmune in origin, usually beginning in early adulthood. The aetiology of the disease is not well understood; it is viewed currently as a multifactorial disease which results from complex interactions between genetic predisposition and environmental factors, of which a few are potentially modifiable. Improving our understanding of these factors can lead to new and more effective approaches to patient counselling and, possibly, prevention and management of the disease. The 2016 focused workshop of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) addressed the topic of environmental, modifiable risk factors for MS, gathering experts from around the world, to collate experimental and clinical research into environmental factors that have been associated with the disease onset and, in a few cases, disease activity and progression. A number of factors, including infections, vitamin D deficiency, diet and lifestyle factors, stress and comorbidities, were discussed. The meeting provided a forum to analyse available evidence, to identify inconsistencies and gaps in current knowledge and to suggest avenues for future research.

Interactions between genetic, lifestyle and environmental risk factors for multiple sclerosis

Genetic predisposition to multiple sclerosis (MS) only explains a fraction of the disease risk; lifestyle and environmental factors are key contributors to the risk of MS. Importantly, these nongenetic factors can influence pathogenetic pathways, and some of them can be modified. Besides established MS-associated risk factors - high latitude, female sex, smoking, low vitamin D levels caused by insufficient sun exposure and/or dietary intake, and Epstein-Barr virus (EBV) infection - strong evidence now supports obesity during adolescence as a factor increasing MS risk. Organic solvents and shift work have also been reported to confer increased risk of the disease, whereas factors such as use of nicotine or alcohol, cytomegalovirus infection and a high coffee consumption are associated with a reduced risk. Certain factors - smoking, EBV infection and obesity - interact with HLA risk genes, pointing at a pathogenetic pathway involving adaptive immunity. All of the described risk factors for MS can influence adaptive and/or innate immunity, which is thought to be the main pathway modulated by MS risk alleles. Unlike genetic risk factors, many environmental and lifestyle factors can be modified, with potential for prevention, particularly for people at the greatest risk, such as relatives of individuals with MS. Here, we review recent data on environmental and lifestyle factors, with a focus on gene-environment interactions.

Negative interaction between smoking and EBV in the risk of multiple sclerosis: The EnvIMS study

Background:

Results from previous studies on a possible interaction between smoking and Epstein–Barr virus (EBV) in the risk of multiple sclerosis (MS) are conflicting.

Objectives:

To examine the interaction between smoking and infectious mononucleosis (IM) in the risk of MS.

Methods:

Within the case–control study on Environmental Factors In Multiple Sclerosis (EnvIMS), 1904 MS patients and 3694 population-based frequency-matched healthy controls from Norway, Italy, and Sweden reported on prior exposure to smoking and history of IM. We examined the interaction between the two exposures on the additive and multiplicative scale.

Results:

Smoking and IM were each found to be associated with an increased MS risk in all three countries, and there was a negative multiplicative interaction between the two exposures in each country separately as well as in the pooled analysis ( p = 0.001). Among those who reported IM, there was no increased risk associated with smoking (odds ratio (OR): 0.95, 95% confidence interval (CI): 0.66–1.37). The direction of the estimated interactions on the additive scale was consistent with a negative interaction in all three countries (relative excess risk due to interaction (RERI): −0.98, 95% CI: −2.05–0.15, p = 0.09).

Conclusion:

Our findings indicate competing antagonism, where the two exposures compete to affect the outcome.

Multiple Sclerosis and Obesity: Possible Roles of Adipokines

Multiple Sclerosis (MS) is an autoimmune disorder of the Central Nervous System that has been associated with several environmental factors, such as diet and obesity. The possible link between MS and obesity has become more interesting in recent years since the discovery of the remarkable properties of adipose tissue. Once MS is initiated, obesity can contribute to increased disease severity by negatively influencing disease progress and treatment response, but, also, obesity in early life is highly relevant as a susceptibility factor and causally related risk for late MS development. The aim of this review was to discuss recent evidence about the link between obesity, as a chronic inflammatory state, and the pathogenesis of MS as a chronic autoimmune and inflammatory disease. First, we describe the main cells involved in MS pathogenesis, both from neural tissue and from the immune system, and including a new participant, the adipocyte, focusing on their roles in MS. Second, we concentrate on the role of several adipokines that are able to participate in the mediation of the immune response in MS and on the possible cross talk between the latter. Finally, we explore recent therapy that involves the transplantation of adipocyte precursor cells for the treatment of MS.

Disability Progression in Multiple Sclerosis Is Affected by the Emergence of Comorbid Arterial Hypertension

BACKGROUND AND PURPOSE

We assessed the prevalence and potential association of hypertension with multiple sclerosis (MS)-related disability progression.

METHODS

This was a retrospective study of 2,813 patients who were followed for 20 years. We modeled the associations of several risk factors with the pattern of disability progression. The primary end point was the rate of disability progression.

RESULTS

In total, 2,396 patients were available for analysis, of which 1,074 (44.8%) scored 4 (EDSS4) on the Expanded Disability Status Scale (EDSS), 717 (29.9%) scored 6 (EDSS6), and 261 (10.9%) scored 8 (EDSS8). The mean times to reach scores of 4, 6, and 8 were 123.5, 163.1, and 218.9 months, respectively. Hypertension was present in 207 (8.6%) patients during follow-up. Hypertension was associated with a higher probability of reaching each EDSS score compared to non-hypertensive patients: 62% vs. 43% for EDSS4 (p<0.01), 51% vs. 28% for EDSS6 (p<0.01), and 17% vs. 10% for EDSS8 (p<0.01). Nevertheless, hypertensive MS patients experienced longer intervals to reach each EDSS score: longer by 51.6, 38.9, and 62.7 months to EDSS4, EDSS6, and EDSS8, respectively (p<0.01) when compared to non-hypertensive MS patients reaching the same EDSS scores.

CONCLUSIONS

Disability progression is more prevalent amongst hypertensive MS patients. However, they experience longer time intervals between the stages of disability progression.

Weighing Evidence from Mendelian Randomization-Early-Life Obesity as a Causal Factor in Multiple Sclerosis?

In this Perspective, Alberto Ascherio and Kassandra Munger discuss the implications of Richards and colleagues' study exploring the role of early-life obesity in risk of multiple sclerosis.

The Norwegian Multiple Sclerosis Registry and Biobank

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with unknown cause and various benefits from disease modifying therapies. Systematic recording of data into national MS registries is therefore needed to optimize treatment and define the pathogenesis of the disease. The Norwegian MS Registry and Biobank was established for systematic collection of clinical and epidemiological data, as well as biological samples. Data collection is based on informed consent from the individual patients and recordings by treating neurologists. All researchers have, by application, access to data and biological samples from the Norwegian Multiple Sclerosis Registry and Biobank. By this combined effort from both patients and healthcare personnel, the Registry and Biobank aims to facilitate research for improved understanding of disease mechanisms and improved health care in MS.

Time trends in the incidence and prevalence of multiple sclerosis in Norway during eight decades

Norway has been subjected to numerous epidemiological investigations on the prevalence and incidence of multiple sclerosis (MS), dating back to 1935. The objective of this study was to review the studies on the prevalence and incidence of MS in Norway, provide an update on the prevalence of MS in Norway, and describe the time trends in the prevalence and incidence of MS in relation to risk factors, case ascertainment, and data. We performed a systematic search on PubMed and MEDLINE up to November 2014 using the search string ‘multiple sclerosis prevalence in Norway’ or ‘multiple sclerosis incidence in Norway’. In addition, we scrutinized the reference lists of the publications identified for relevant citations. We retrieved data on the distribution of MS in Norway on December 31, 2013 from the Norwegian Multiple Sclerosis Registry and Biobank and the Norwegian Patient Registry. We identified 29 articles. From 1961 to 2014, the reported prevalence of MS increased from 20 to 203 per 100,000 inhabitants, and the incidence increased from 1.9 to 8.0 per 100,000. The nationwide crude prevalence in Norway, based on the Norwegian Patient Registry, was 208 per 100,000 on December 31, 2013. The reported prevalence of MS in Norway has increased 10-fold, with several possible causes. During eight decades, neurological health services have generally become more accessible to the population, and transforming diagnostic criteria has made the diagnosis of MS more precise and valid. There have also been changes in lifestyle behavior and known risk factors, such as vitamin D and smoking, that might have contributed to the increased incidence of MS. A possible role of increased survival in MS needs to be examined further.

This article is commented on by Berg-Hansen et al, published in 132: 364–367 (DOI: 10.1111/ane.12489).

The epidemiology of multiple sclerosis: insights to a causal cascade

MS-pathogenesis involves both genetic-susceptibility and environmental determinants. Three (or more) sequential environmental-factors are implicated. The first acts near birth, the second acts during childhood/adolescence, and the third acts subsequently. Two candidate factors (vitamin D deficiency and Epstein-Barr viral infection) seem particularly well-suited to the first two environmental-events but other factors (e.g., obesity and smoking behavior) seem also to be involved in the causal scheme. MS-pathogenesis can be modeled by incorporating both the environmental and genetic-factors into a causal scheme, which can then help to explain some of the changes in MS-epidemiology (e.g., increasing disease-prevalence, changing sex-ratio, and regional-variations in monozygotic-twin-concordance-rates), which have been taking place recently. This model suggests that genetic-susceptibility is overwhelmingly the most important determinant of MS and that, at least, 92.5% of individuals (and likely much more) are, essentially, incapable of developing MS, regardless of their specific environmental-exposures. Nevertheless, the genetics is complex and the contribution of any specific gene to MS-susceptibility seems to be quite modest. Thus, even for the DRB1*1501 allele (the strongest known MS-susceptibility marker), most carriers are not in the genetically-susceptible group. Moreover, 45-50% of individuals with MS lack this allele entirely and some of the haplotypes that carry this allele don't also confer any disease-risk. Finally, because the prevalence of genetic-susceptibility seems to be so similar throughout North America and Europe, and despite the crucial importance of a person's genetic make-up to disease pathogenesis, it is the environmental-factors, which largely responsible for the observed regional variations in disease-characteristics. Thus, despite MS being more common in women, men are more likely to be genetically-susceptible. This apparent paradox seems to relate to the fact that women are much more responsive than men to the recent changes in environmental-exposure (whatever these have been). These gender-differences may help to explain changes in the sex-ratio and the increasing disease-prevalence, which have both been observed recently. The potential importance of these conclusions regarding the role of environment in MS-pathogenesis is that they open the door to the possibility of pursuing strategies for primary primary disease prevention in the future.

Level of education and multiple sclerosis risk after adjustment for known risk factors: The EnvIMS study

BACKGROUND

Several recent studies have found a higher risk of multiple sclerosis (MS) among people with a low level of education. This has been suggested to reflect an effect of smoking and lower vitamin D status in the social class associated with lower levels of education.

OBJECTIVE

The objective of this paper is to investigate the association between level of education and MS risk adjusting for the known risk factors smoking, infectious mononucleosis, indicators of vitamin D levels and body size.

METHODS

Within the case-control study on Environmental Factors In MS (EnvIMS), 953 MS patients and 1717 healthy controls from Norway reported educational level and history of exposure to putative environmental risk factors.

RESULTS

Higher level of education were associated with decreased MS risk (p trend = 0.001) with an OR of 0.53 (95% CI 0.41-0.68) when comparing those with the highest and lowest level of education. This association was only moderately reduced after adjusting for known risk factors (OR 0.61, 95% CI 0.44-0.83). The estimates remained similar when cases with disease onset before age 28 were excluded.

CONCLUSION

These findings suggest that factors related to lower socioeconomic status other than established risk factors are associated with MS risk.

Body mass index during adolescence, rather than childhood, is critical in determining MS risk

OBJECTIVE

Obesity in childhood and during adolescence has repeatedly been associated with increased risk of developing multiple sclerosis (MS). We aimed to investigate whether the most critical period occurs during childhood or later, during adolescence.

METHODS

Using a population-based case-control study (1586 cases and 2800 controls), individuals with different body sizes at age 10 and different body mass indices at age 20 were compared regarding MS risk, by calculating odds ratios with 95% confidence intervals. Potential interactions between HLA-DRB1*15 and absence of HLA-A*02, respectively, and both childhood and adolescent obesity were evaluated by calculating the attributable proportion due to interaction.

RESULTS

Regardless of body size at age 10, individuals with adolescent obesity had a 90% increased risk of MS. Among participants who were not obese at age 20, no association was observed between body size at age 10 and subsequent MS risk. An interaction was observed between the HLA MS risk genes and adolescent, but not childhood, obesity.

CONCLUSIONS

Our results suggest that BMI during adolescence, rather than childhood, is critical in determining MS risk.

Does the changing sex ratio of multiple sclerosis give opportunities for intervention?

In several international studies, an increasing women-to-men (w/m) ratio in patients with multiple sclerosis (MS) has been reported. Such sex ratios have been analysed by year of onset or by year of birth. In a Swedish study, data from the Swedish MS register (SMSreg) were used to analyse the w/m ratio in Sweden. The sex ratio was analysed both by year of birth (8834 patients) and by year of onset (9098 patients). No increased w/m ratio was seen in this study. The age-specific sex ratio did not demonstrate any significant changes. However, a new investigation of the sex ratio in Sweden, based on data from all available data sources (19,510 patients), showed a significantly increased w/m ratio of MS in Sweden from 1.70 to 2.67. Environmental factors such as cigarette smoking, hormonal factors and nutrition are of interest in this context, but the cause of the increasing w/m ratio in MS is yet not possible to explain.

The EnvIMS Study: Design and Methodology of an International Case-Control Study of Environmental Risk Factors in Multiple Sclerosis

Background: Multiple sclerosis (MS) is a chronic disease of the central nervous system, often resulting in significant neurological disability. The causes of MS are not known; however, the incidence of MS is increasing, thereby suggesting that changes in lifestyle and/or environmental factors may be responsible. On this background, the Environmental Risk Factors in MS Study or EnvIMS study was designed to further explore the etiology of MS. The design and methodology are described, providing details to enable investigators to (i) use our experiences to design their own studies; (ii) take advantage of, and build on the methodological work completed for, the EnvIMS study; (iii) become aware of this data source that is available for use by the research community. Methods: EnvIMS is a multinational case-control study, enrolling 2,800 cases with MS and 5,012 population-based controls in Canada, Italy, Norway, Serbia and Sweden. The study was designed to investigate the most commonly implicated risk factors for MS etiology using a self-report questionnaire. Results/Conclusions: The use of a common methodology to study MS etiology across several countries enhances the comparability of results in different geographic regions and research settings, reduces the resources required for study design and enhances the opportunity for data harmonization.