Role of diet in regulating the gut microbiota and multiple sclerosis

A diet-dependent host metabolite shapes the gut microbiota to protect from autoimmunity

Diet can protect from autoimmune disease; however, whether diet acts via the host and/or microbiome remains unclear. Here, we use a ketogenic diet (KD) as a model to dissect these complex interactions. A KD rescued the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis in a microbiota-dependent fashion. Dietary supplementation with a single KD-dependent host metabolite (β-hydroxybutyrate, βHB) rescued EAE whereas transgenic mice unable to produce βHB in the intestine developed more severe disease. Transplantation of the βHB-shaped gut microbiota was protective. Lactobacillus sequence variants were associated with decreased T helper 17 (Th17) cell activation in vitro . Finally, we isolated a L. murinus strain that protected from EAE, which was phenocopied by the Lactobacillus metabolite indole lactic acid. Thus, diet alters the immunomodulatory potential of the gut microbiota by shifting host metabolism, emphasizing the utility of taking a more integrative approach to study diet-host-microbiome interactions.

Targeting gut microbiota: new therapeutic opportunities in multiple sclerosis

Multiple sclerosis (MS) causes long-lasting, multifocal damage to the central nervous system. The complex background of MS is associated with autoimmune inflammation and neurodegeneration processes, and is potentially affected by many contributing factors, including altered composition and function of the gut microbiota. In this review, current experimental and clinical evidence is presented for the characteristics of gut dysbiosis found in MS, as well as for its relevant links with the course of the disease and the dysregulated immune response and metabolic pathways involved in MS pathology. Furthermore, therapeutic implications of these investigations are discussed, with a range of pharmacological, dietary and other interventions targeted at the gut microbiome and thus intended to have beneficial effects on the course of MS.

Ketogenic diet may improve sleep quality and daytime somnolence in patients affected by multiple sclerosis. Results of an exploratory study

OBJECTIVE/BACKGROUND

Patients with multiple sclerosis (MS) frequently report sleep complaints. The ketogenic diet (KD) is safe and tolerable in MS patients. Our aim was: 1) to investigate the effects of KD on sleep complaints in patients affected by relapsing-remitting MS and 2) to verify if sleep changes can positively impact on psychological status and quality of life (QoL) in these patients.

PATIENTS/METHODS

From January 2020 to November 2022, we consecutively enrolled 21 non-disabled or minimally disabled MS patients. We collected information regarding: 1) anthropometric measures; 2) psychological status by the Depression Anxiety Stress Scale-21; 3) QoL by the Multiple Sclerosis Quality of Life-54 (MSQOL-54); 4) subjective sleep complaints, i.e. sleep quality, by the Pittsburgh Sleep Quality Index (PSQI), and excessive daytime sleepiness (EDS), by the Epworth Sleepiness Scale (ESS).

RESULTS

After 6 months of KD therapy, anthropometric measures considerably changed, psychological status significantly improved, and almost all the MSQOL-54 subscales ameliorated. Regarding sleep, we observed that the global PSQI (T0: 7.7 ± 3.1 versus T1: 4.4 ± 3.1, p = 0.002) and the ESS (T0: 7.5 ± 3.9 versus T1: 4.9 ± 3.2, p = 0.001) scores significantly decreased after KD therapy. At T1, only the global PSQI score was an independent predictor of anxiety, stress, and mental health.

CONCLUSIONS

For the first time, we demonstrated that KD may improve sleep complaints in MS patients. In addition, KD seems to have a positive impact on psychological status and QoL of MS patients, mainly through improving sleep quality. Further controlled studies with larger sample sizes are needed to confirm these preliminary results.

Multiple Sclerosis-Associated Gut Microbiome in the Israeli Diverse Populations: Associations with Ethnicity, Gender, Disability Status, Vitamin D Levels, and Mediterranean Diet

Microbiome dysbiosis is increasingly being recognized as implicated in immune-mediated disorders including multiple sclerosis (MS). The microbiome is modulated by genetic and environmental factors including lifestyle, diet, and drug intake. This study aimed to characterize the MS-associated gut microbiome in the Israeli populations and to identify associations with demographic, dietary, and clinical features. The microbiota from 57 treatment-naive patients with MS (PwMS) and 43 age- and gender-matched healthy controls (HCs) was sequenced and abundance compared. Associations between differential microbes with demographic or clinical characteristics, as well as diet and nutrient intake, were assessed. While there was no difference in α- or β-diversity of the microbiome, we identified 40 microbes from different taxonomic levels that differ in abundance between PwMS and HCs, including Barnesiella, Collinsella, Egerthella, Mitsuokella, Olsenella Romboutsia, and Succinivibrio, all enhanced in PwMS, while several members of Lacnospira were reduced. Additional MS-differential microbes specific to ethnicity were identified. Several MS-specific microbial patterns were associated with gender, vitamin D level, Mediterranean diet, nutrient intake, or disability status. Thus, PwMS have altered microbiota composition, with distinctive patterns related to geographic locations and population. Microbiome dysbiosis seem to be implicated in disease progression, gender-related differences, and vitamin D-mediated immunological effects recognized in MS. Dietary interventions may be beneficial in restoring a "healthy microbiota" as part of applying comprehensive personalized therapeutic strategies for PwMS.

Impact of High Salt-Intake on a Natural Gut Ecosystem in Wildling Mice

The mammalian holobiont harbors a complex and interdependent mutualistic gut bacterial community. Shifts in the composition of this bacterial consortium are known to be a key element in host health, immunity and disease. Among many others, dietary habits are impactful drivers for a potential disruption of the bacteria–host mutualistic interaction. In this context, we previously demonstrated that a high-salt diet (HSD) leads to a dysbiotic condition of murine gut microbiota, characterized by a decrease or depletion of well-known health-promoting gut bacteria. However, due to a controlled and sanitized environment, conventional laboratory mice (CLM) possess a less diverse gut microbiota compared to wild mice, leading to poor translational outcome for gut microbiome studies, since a reduced gut microbiota diversity could fail to depict the complex interdependent networks of the microbiome. Here, we evaluated the HSD effect on gut microbiota in CLM in comparison to wildling mice, which harbor a natural gut ecosystem more closely mimicking the situation in humans. Mice were treated with either control food or HSD and gut microbiota were profiled using amplicon-based methods targeting the 16S ribosomal gene. In line with previous findings, our results revealed that HSD induced significant loss of alpha diversity and extensive modulation of gut microbiota composition in CLM, characterized by the decrease in potentially beneficial bacteria from Firmicutes phylum such as the genera Lactobacillus, Roseburia, Tuzzerella, Anaerovorax and increase in Akkermansia and Parasutterella. However, HSD-treated wildling mice did not show the same changes in terms of alpha diversity and loss of Firmicutes bacteria as CLM, and more generally, wildlings exhibited only minor shifts in the gut microbiota composition upon HSD. In line with this, 16S-based functional analysis suggested only major shifts of gut microbiota ecological functions in CLM compared to wildling mice upon HSD. Our findings indicate that richer and wild-derived gut microbiota is more resistant to dietary interventions such as HSD, compared to gut microbiota of CLM, which may have important implications for future translational microbiome research.

Body size perceptions & diet modification in youth with multiple sclerosis

BACKGROUND

Investigate the perceptions of pediatric multiple sclerosis (MS) patients regarding their body size and assess the feasibility of recruitment for a study of diet modification in this unique population.

METHODS

This cross-sectional study surveyed a cohort of 43 consecutive youth with MS. The survey queried participant demographics, clinical disease characteristics, body size perception, and opinions of diet modification RESULTS: : While over three quarters of surveyed participants were overweight/obese, 58% of these participants did not self-identify as such. A single participant was attempting a diet at the time of survey, but 88% of participants indicated interest in pursuing diet modification. BMI category did not impact an individual's willingness to pursue diet intervention; however, obese participants were more willing to participate in diet intervention for longer durations.

CONCLUSION

A significant proportion of MS youth have an elevated BMI, yet the majority have the self-perception that they are not overweight or obese. Regardless of BMI, most youth with MS have an interest in pursuing diet modification in attempts to benefit their disease course.

Obesity and Multiple Sclerosis-A Multifaceted Association

BACKGROUND

Given the common elements in the pathophysiological theories that try to explain the appearance and evolution of obesity and multiple sclerosis, the association between the two pathologies has become an increasingly researched topic in recent years. On the one hand, there is the chronic demyelinating inflammation caused by the autoimmune cascade of multiple sclerosis, while on the other hand, according to the latest research, it has been shown that obesity shares an inflammatory component with most chronic diseases.

METHODS

The authors performed independent research of the available literature in the most important electronic databases (PubMed, Google Scholar, Embase, and Science Direct) in February 2021. After applying the exclusion criteria, the reviewers focused on the most relevant articles published during the last 10 years with respect to epidemiology and pathophysiology.

RESULTS

The data presented are a step forward in trying to elucidate the intricate relationship between obesity and MS, especially the causal relationship between childhood and adolescent obesity and MS, focusing on the epidemiological associations observed in the most relevant observational studies conducted in recent years. In the second part, the authors comment on the latest findings related to the pathophysiological mechanisms that may explain the correlations between obesity and multiple sclerosis, focusing also on the role of adipokines.

CONCLUSIONS

Based on available epidemiological data, obesity in early life appears to be strongly associated with a higher risk of MS development, independent of other risk factors. Although much research has been done on the pathophysiology of obesity, MS, their possible common mechanism, and the role of adipokines, further studies are needed in order to explain what remains unknown. No relevant data were found regarding the association between obesity, disability (high EDSS score), and mortality risk in MS patients. Thus, we consider that this topic should be elucidated in future research.

Self-Reported Diet and Health Outcomes of Participants of the CCSVI-Tracking Survey Study

Of the 1575 participants of the CCSVI-Tracking Survey, 475 patients recorded their quality of life and EDSS outcomes for at least 2 months. Self-reported use of complementary and conventional therapies included diet, use of drug therapy, symptoms, quality of life, and mobility. Analysis included comparing outcomes related to different diets within and between groups. Adherence to the MS diet was not associated with a greater quality of life, less disability, a lower Symptom Score, or faster walking speed compared to other diets. Alternately, the participants from the Mediterranean diet region as a whole (µ = 32.65 (SD = 11.37, SE_M = 2.37, p = 0.05) had a significantly greater QoL (µ = 60, p = 0.05) and a lower MS symptom score, µ = 32.65 (11.37), p = 0.0029. A decline of symptoms was observed in all diet groups over 3 months with the most dramatic decline observed in participants from the Eastern Mediterranean diet region. The main effect for the within-subjects factor was significant, F(3, 1056) = 55.95, p < 0.001, indicating that there were significant differences between the groups.

The Role of Vitamin K in Humans: Implication in Aging and Age-Associated Diseases

As human life expectancy is rising, the incidence of age-associated diseases will also increase. Scientific evidence has revealed that healthy diets, including good fats, vitamins, minerals, or polyphenolics, could have antioxidant and anti-inflammatory activities, with antiaging effects. Recent studies demonstrated that vitamin K is a vital cofactor in activating several proteins, which act against age-related syndromes. Thus, vitamin K can carboxylate osteocalcin (a protein capable of transporting and fixing calcium in bone), activate matrix Gla protein (an inhibitor of vascular calcification and cardiovascular events) and carboxylate Gas6 protein (involved in brain physiology and a cognitive decline and neurodegenerative disease inhibitor). By improving insulin sensitivity, vitamin K lowers diabetes risk. It also exerts antiproliferative, proapoptotic, autophagic effects and has been associated with a reduced risk of cancer. Recent research shows that protein S, another vitamin K-dependent protein, can prevent the cytokine storm observed in COVID-19 cases. The reduced activation of protein S due to the pneumonia-induced vitamin K depletion was correlated with higher thrombogenicity and possibly fatal outcomes in COVID-19 patients. Our review aimed to present the latest scientific evidence about vitamin K and its role in preventing age-associated diseases and/or improving the effectiveness of medical treatments in mature adults ˃50 years old.

Molecular patterns from a human gut-derived Lactobacillus strain suppress pathogenic infiltration of leukocytes into the central nervous system

BACKGROUND

Multiple sclerosis (MS) is an inflammatory demyelinating disease that affects 2.5 million people worldwide. Growing evidence suggests that perturbation of the gut microbiota, the dense collection of microorganisms that colonize the gastrointestinal tract, plays a functional role in MS. Indeed, specific gut-resident bacteria are altered in patients with MS compared to healthy individuals, and colonization of gnotobiotic mice with MS-associated microbiota exacerbates preclinical models of MS. However, defining the molecular mechanisms by which gut commensals can remotely affect the neuroinflammatory process remains a critical gap in the field.

METHODS

We utilized monophasic experimental autoimmune encephalomyelitis (EAE) in C57BL/6J mice and relapse-remitting EAE in SJL/J mice to test the effects of the products from a human gut-derived commensal strain of Lactobacillus paracasei (Lb).

RESULTS

We report that Lb can ameliorate preclinical murine models of MS with both prophylactic and therapeutic administrations. Lb ameliorates disease through a Toll-like receptor 2-dependent mechanism via its microbe-associated molecular patterns that can be detected in the systemic circulation, are sufficient to downregulate chemokine production, and can reduce immune cell infiltration into the central nervous system (CNS). In addition, alterations in the gut microbiota mediated by Lb-associated molecular patterns are sufficient to provide partial protection against neuroinflammatory diseases.

CONCLUSIONS

Local Lb modulation of the gut microbiota and the shedding of Lb-associated molecular patterns into the circulation may be important physiological signals to prevent aberrant peripheral immune cell infiltration into the CNS and have relevance to the development of new therapeutic strategies for MS.