The gut microbiota in multiple sclerosis varies with disease activity

The emerging role of circular RNAs in cisplatin resistance in ovarian cancer: From molecular mechanism to future potential

Ovarian cancer (OC) is the most common cause of death in female cancers. The prognosis of OC is very poor due to delayed diagnosis and identification of most patients in advanced stages, metastasis, recurrence, and resistance to chemotherapy. As chemotherapy with platinum-based drugs such as cisplatin (DDP) is the main treatment in most OC cases, resistance to DDP is an important obstacle to achieving satisfactory therapeutic efficacy. Consequently, knowing the different molecular mechanisms involved in resistance to DDP is necessary to achieve new therapeutic approaches. According to numerous recent studies, non-coding RNAs (ncRNAs) could regulate proliferation, differentiation, apoptosis, and chemoresistance in many cancers, including OC. Most of these ncRNAs are released by tumor cells into human fluid, allowing them to be used as tools for diagnosis. CircRNAs are ncRNA family members that have a role in the initiation, progression, and chemoresistance regulation of various cancers. In the current study, we investigated the roles of several circRNAs and their signaling pathways on OC progression and also on DDP resistance during chemotherapy.

A randomized cross-over trial of prebiotics and probiotics in multiple sclerosis: Trial feasibility, supplement tolerability and symptom abatement

BACKGROUND

Dietary supplements can modulate the gut microbial ecosystem and affect the immune system. This has potential implications for autoimmune diseases, including multiple sclerosis (MS). Prior studies explored tolerability, symptomatic improvement, and immunologic effects of probiotics in people with MS (pwMS), but no study has examined prebiotics in this population or compared prebiotics with probiotics.

METHODS

This is a randomized, open-label trial of participants with relapsing-remitting MS on B-cell depletion therapy from two MS centers. 22 participants enrolled in the original cross-over study in which probiotic (Visbiome, containing Lactobacillus, Bifidobacterium and Streptococcus species) or prebiotic (Prebiotin, containing oligofructose enriched inulin) supplementation for 6 weeks was randomized, each followed by a washout period. Due to pandemic-related interruptions and expiration of the study supply of probiotics, another 15 participants enrolled in a single-arm study to receive prebiotic supplementation for 6 weeks followed by a washout period. We assessed supplement tolerability and patient-reported outcomes (PRO) relevant to MS (disability, fatigue, mood, and bowel symptoms) before and after each supplement administration period and each washout period. We bio-archived plasma, serum, peripheral blood mononuclear cells and stool samples at each timepoint for future multi-omic assessment.

RESULTS

Prebiotics and probiotics had comparable adherence rates and both supplements were well tolerated in pwMS. Participants on either supplement reported minor adverse events, most of which were mild and self-limited. There was a subjective preference for prebiotics over probiotics. Comparing supplement-associated changes in PRO scores from baseline to 6 weeks post-supplementation, there were significant difference between prebiotics and probiotics for the change in patient-reported global symptom burden (MSRS-R Total) and bowel control (BWCS), but only probiotics statistically improved bowel control from baseline to post-supplementation.

CONCLUSION

Supplementation with either prebiotics or probiotics is reasonably well-tolerated and safe. Probiotics improved bowel control, but did not improve other PROs in a 6-week time frame. These data regarding feasibility, tolerability, adherence, and adverse events of supplements will inform future clinical trial designs to definitively compare the efficacy and safety of prebiotics and probiotics. The biological data that will be generated from this study in the future will provide mechanistic insights into the effects of these dietary supplements on MS pathophysiology.

Identification of commensal gut microbiota signatures as predictors of clinical severity and disease progression in multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system and a leading cause of neurological disability in young adults. Clinical presentation and disease course are highly heterogeneous. Typically, disease progression occurs over time and is characterized by the gradual accumulation of disability. The risk of developing MS is driven by complex interactions between genetic and environmental factors, including the gut microbiome. How the commensal gut microbiota impacts disease severity and progression over time remains unknown. In a longitudinal study, disability status and associated clinical features in 58 MS patients were tracked over 4.2 ± 0.98 years, and the baseline fecal gut microbiome was characterized via 16S amplicon sequencing. Progressor status, defined as patients with an increase in Expanded Disability Status Scale (EDSS), were correlated with features of the gut microbiome to determine candidate microbiota associated with risk of MS disease progression. We found no overt differences in microbial community diversity and overall structure between MS patients exhibiting disease progression and non-progressors. However, a total of 41 bacterial species were associated with worsening disease, including a marked depletion in Akkermansia, Lachnospiraceae, and Oscillospiraceae, with an expansion of Alloprevotella, Prevotella-9, and Rhodospirillales. Analysis of the metabolic potential of the inferred metagenome from taxa associated with progression revealed enrichment in oxidative stress-inducing aerobic respiration at the expense of microbial vitamin K2 production (linked to Akkermansia), and a depletion in SCFA metabolism (linked to Oscillospiraceae). Further, as a proof of principle, statistical modeling demonstrated that microbiota composition and clinical features were sufficient to predict disease progression. Additionally, we found that constipation, a frequent gastrointestinal comorbidity among MS patients, exhibited a divergent microbial signature compared with progressor status. These results demonstrate a proof of principle for the utility of the gut microbiome for predicting disease progression in MS in a small well-defined cohort. Further, analysis of the inferred metagenome suggested that oxidative stress, vitamin K2, and SCFAs are associated with progression, warranting future functional validation and mechanistic study.

Rethinking neurodegenerative diseases: neurometabolic concept linking lipid oxidation to diseases in the central nervous system

ABSTRACT

Currently, there is a lack of effective medicines capable of halting or reversing the progression of neurodegenerative disorders, including amyotrophic lateral sclerosis, Parkinson's disease, multiple sclerosis, or Alzheimer's disease. Given the unmet medical need, it is necessary to reevaluate the existing paradigms of how to target these diseases. When considering neurodegenerative diseases from a systemic neurometabolic perspective, it becomes possible to explain the shared pathological features. This innovative approach presented in this paper draws upon extensive research conducted by the authors and researchers worldwide. In this review, we highlight the importance of metabolic mitochondrial dysfunction in the context of neurodegenerative diseases. We provide an overview of the risk factors associated with developing neurodegenerative disorders, including genetic, epigenetic, and environmental factors. Additionally, we examine pathological mechanisms implicated in these diseases such as oxidative stress, accumulation of misfolded proteins, inflammation, demyelination, death of neurons, insulin resistance, dysbiosis, and neurotransmitter disturbances. Finally, we outline a proposal for the restoration of mitochondrial metabolism, a crucial aspect that may hold the key to facilitating curative therapeutic interventions for neurodegenerative disorders in forthcoming advancements.

Multiple Sclerosis and Clostridium perfringens Epsilon Toxin: Is There a Relationship?

Recent research has suggested a link between multiple sclerosis and the gut microbiota. This prospective pilot study aimed to investigate the composition of the gut microbiota in MS patients, the presence of Clostridium perfringens epsilon toxin in the serum of MS patients, and the influence of disease-modifying drugs (DMDs) on epsilon toxin levels and on the microbiota. Epsilon toxin levels in blood were investigated by two methods, a qualitative ELISA and a highly sensitive quantitative ELISA. Neither epsilon toxin nor antibodies against it were detected in the analyzed serum samples. 16S ribosomal RNA sequencing was applied to obtain insights into the composition of the gut microbiota of MS patients. No significant differences in the quantity, diversity, and the relative abundance of fecal microbiota were observed in the gut microbiota of MS patients receiving various DMDs, including teriflunomide, natalizumab, ocrelizumab, and fingolimod, or no therapy. The present study did not provide evidence supporting the hypothesis of a causal relationship between Clostridium perfringens epsilon toxin and multiple sclerosis.

The influence of aging and the microbiome in multiple sclerosis and other neurologic diseases

The human gut microbiome is well-recognized as a key player in maintaining health. However, it is a dynamic entity that changes across the lifespan. How the microbial changes that occur in later decades of life shape host health or impact age-associated inflammatory neurological diseases such as multiple sclerosis (MS) is still unclear. Current understanding of the aging gut microbiome is largely limited to cross-sectional observational studies. Moreover, studies in humans are limited by confounding host-intrinsic and extrinsic factors that are not easily disentangled from aging. This review provides a comprehensive summary of existing literature on the aging gut microbiome and its known relationships with neurological diseases, with a specific focus on MS. We will also discuss preclinical animal models and human studies that shed light on the complex microbiota-host interactions that have the potential to influence disease pathology and progression in aging individuals. Lastly, we propose potential avenues of investigation to deconvolute features of an aging microbiota that contribute to disease, or alternatively promote health in advanced age.

From Skin and Gut to the Brain: The Infectious Journey of the Human Commensal Fungus Malassezia and Its Neurological Consequences

The human mycobiome encompasses diverse communities of fungal organisms residing within the body and has emerged as a critical player in shaping health and disease. While extensive research has focused on the skin and gut mycobiome, recent investigations have pointed toward the potential role of fungal organisms in neurological disorders. Among those fungal organisms, the presence of the commensal fungus Malassezia in the brain has created curiosity because of its commensal nature and primary association with the human skin and gut. This budding yeast is responsible for several diseases, such as Seborrheic dermatitis, Atopic dermatitis, Pityriasis versicolor, Malassezia folliculitis, dandruff, and others. However recent findings surprisingly show the presence of Malassezia DNA in the brain and have been linked to diseases like Alzheimer's disease, Parkinson's disease, Multiple sclerosis, and Amyotrophic lateral sclerosis. The exact role of Malassezia in these disorders is unknown, but its ability to infect human cells, travel through the bloodstream, cross the blood-brain barrier, and reside along with the lipid-rich neuronal cells are potential mechanisms responsible for pathogenesis. This also includes the induction of pro-inflammatory cytokines, disruption of the blood-brain barrier, gut-microbe interaction, and accumulation of metabolic changes in the brain environment. In this review, we discuss these key findings from studies linking Malassezia to neurological disorders, emphasizing the complex and multifaceted nature of these cases. Furthermore, we discuss potential mechanisms through which Malassezia might contribute to the development of neurological conditions. Future investigations will open up new avenues for our understanding of the fungal gut-brain axis and how it influences human behavior. Collaborative research efforts among microbiologists, neuroscientists, immunologists, and clinicians hold promise for unraveling the enigmatic connections between human commensal Malassezia and neurological disorders.

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

Host-microbe interactions: communication in the microbiota-gut-brain axis

Animals harbor a diverse array of symbiotic micro-organisms that coexist in communities across different body sites. These microbes maintain host homeostasis and respond to environmental insults to impact host physiological processes. Trillions of indigenous microbes reside in the gastrointestinal tract and engage with the host central nervous system (microbiota-gut-brain axis) by modulating immune responses, interacting with gut intrinsic and extrinsic nervous system, and regulating neuromodulators and biochemicals. These gut microbiota to brain signaling pathways are constantly informed by each other and are hypothesized to mediate brain health across the lifespan. In this review, we will examine the crosstalk of gut microbiota to brain communications in neurological pathologies, with an emphasis on microbial metabolites and neuromodulators, and provide a discussion of recent advances that help elucidate the microbiota as a therapeutic target for treating brain and behavioral disorders.

The Impact of Pulmonary Disorders on Neurological Health (Lung-Brain Axis)

The brain and lungs, vital organs in the body, play essential roles in maintaining overall well-being and survival. These organs interact through complex and sophisticated bi-directional pathways known as the 'lung-brain axis', facilitated by their close proximity and neural connections. Numerous studies have underscored the mediation of the lung-brain axis by inflammatory responses and hypoxia-induced damage, which are pivotal to the progression of both pulmonary and neurological diseases. This review aims to delve into how pulmonary diseases, including acute/chronic airway diseases and pulmonary conditions, can instigate neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. Additionally, we highlight the emerging research on the lung microbiome which, drawing parallels between the gut and lungs in terms of microbiome contents, may play a significant role in modulating brain health. Ultimately, this review paves the way for exciting avenues of future research and therapeutics in addressing respiratory and neurological diseases.

Cognitive impairment in multiple sclerosis: from phenomenology to neurobiological mechanisms

Multiple sclerosis (MS) is an autoimmune-mediated disease of the central nervous system characterized by inflammation, demyelination and chronic progressive neurodegeneration. Among its broad and unpredictable range of clinical symptoms, cognitive impairment (CI) is a common and disabling feature greatly affecting the patients' quality of life. Its prevalence is 20% up to 88% with a wide variety depending on the phenotype of MS, with highest frequency and severity in primary progressive MS. Involving different cognitive domains, CI is often associated with depression and other neuropsychiatric symptoms, but usually not correlated with motor and other deficits, suggesting different pathophysiological mechanisms. While no specific neuropathological data for CI in MS are available, modern research has provided evidence that it arises from the disease-specific brain alterations. Multimodal neuroimaging, besides structural changes of cortical and deep subcortical gray and white matter, exhibited dysfunction of fronto-parietal, thalamo-hippocampal, default mode and cognition-related networks, disruption of inter-network connections and involvement of the γ-aminobutyric acid (GABA) system. This provided a conceptual framework to explain how aberrant pathophysiological processes, including oxidative stress, mitochondrial dysfunction, autoimmune reactions and disruption of essential signaling pathways predict/cause specific disorders of cognition. CI in MS is related to multi-regional patterns of cerebral disturbances, although its complex pathogenic mechanisms await further elucidation. This article, based on systematic analysis of PubMed, Google Scholar and Cochrane Library, reviews current epidemiological, clinical, neuroimaging and pathogenetic evidence that could aid early identification of CI in MS and inform about new therapeutic targets and strategies.

Potential Applications of Blautia wexlerae in the Regulation of Host Metabolism

Blautia wexlerae (B. wexlerae) is a strong candidate with the potential to become a next-generation probiotics (NGPs) and has recently been shown for the first time to exhibit potential in modulating host metabolic levels and alleviating metabolic diseases. However, the factors affecting the change in abundance of B. wexlerae and the pattern of its abundance change in the associated indications remain to be further investigated. Here, we summarize information from published studies related to B. wexlerae; analyze the effects of food source factors such as prebiotics, probiotics, low protein foods, polyphenols, vitamins, and other factors on the abundance of B. wexlerae; and explore the patterns of changes in the abundance of B. wexlerae in metabolic diseases, neurological diseases, and other diseases. At the same time, the development potential of B. wexlerae was evaluated in the direction of functional foods and special medical foods.

The infant gut microbiome and cognitive development in malnutrition

Malnutrition affects 195 million children under the age of five worldwide with long term effects that include impaired cognitive development. Brain development occurs rapidly over the first 36 months of life. Whilst seemingly independent, changes to the brain and gut microbiome are linked by metabolites, hormones, and neurotransmitters as part of the gut-brain axis. In the context of severe malnutrition, the composition of the gut microbiome and the repertoire of biochemicals exchanged via the gut-brain axis vary when compared to healthy individuals. These effects are primarily due to the recognized interacting determinants, macro- and micronutrient deficiencies, infection, infestations and toxins related to poor sanitation, and a dearth of psycho-social stimulation. The standard of care for the treatment of severe acute malnutrition is focused on nutritional repletion and weight restoration through the provision of macro- and micronutrients, the latter usually in excess of recommended dietary allowances (RDA). However, existing formulations and supplements have not been designed to specifically address key recovery requirements for brain and gut microbiome development. Animal model studies indicate that treatments targeting the gut microbiome could improve brain development. Despite this, research on humans targeting the gut microbiome with the aim of restoring brain functionality are scarce. We conclude that there is a need for assessment of cognition and the use of various tools that permit visualization of the brain anatomy and function (e.g., Magnetic resonance imaging (MRI), functional near-infrared spectroscopy (fNIRS), electroencephalogram (EEG)) to understand how interventions targeting the gut microbiome impact brain development.

Advances in molecular mechanisms and therapeutic strategies for central nervous system diseases based on gut microbiota imbalance

BACKGROUD

Central nervous system (CNS) diseases pose a serious threat to human health, but the regulatory mechanisms and therapeutic strategies of CNS diseases need to be further explored. It has been demonstrated that the gut microbiota (GM) is closely related to CNS disease. GM structure disorders, abnormal microbial metabolites, intestinal barrier destruction and elevated inflammation exist in patients with CNS diseases and promote the development of CNS diseases. More importantly, GM remodeling alleviates CNS pathology to some extent.

AIM OF REVIEW

Here, we have summarized the regulatory mechanism of the GM in CNS diseases and the potential treatment strategies for CNS repair based on GM regulation, aiming to provide safer and more effective strategies for CNS repair from the perspective of GM regulation.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The abundance and composition of GM is closely associated with the CNS diseases. On the basis of in-depth analysis of GM changes in mice with CNS disease, as well as the changes in its metabolites, therapeutic strategies, such as probiotics, prebiotics, and FMT, may be used to regulate GM balance and affect its microbial metabolites, thereby promoting the recovery of CNS diseases.

In-silico characterization of GABAT protein found in gut-brain axis associated bacteria of healthy individuals and multiple sclerosis patients

Background

Multiple sclerosis (MS) is a neurodegenerative disease characterized by inflammation and demyelination of neurons. There is evidence to suggest that level of a neurotransmitter gamma-aminobutyric acid (GABA), due to the degradation by γ-aminobutyric acid transaminase (GABAT), is reduced in certain areas of the brain in MS patients. MS is always accompanied by gut bacteria dysbiosis. In healthy individuals, Faecalibacterium sp. while in MS patients A. calcoaceticus, Clostridium sp. and S. typhimurium are found abundantly. Although all these microbes produce GABAT but only in MS patients this enzyme significantly degrades GABA.

Objective

Present study is an attempt to characterize the GABAT protein sequences of these bacteria.

Methodology

Sequences of GABAT protein were retrieved from Uniprot database. Sequences were analyzed by Protparam, Gneg-mPLoc, SOSUI, PFP-FunDSeqE, Pepwheel program, PROTEUS and Alphafold and SAVES servers, MEME suite and HDOCK server.

Results

In healthy individuals gastrointestinal tract (GIT) bacteria, GABAT protein was present in inner-membrane with α helix content (61 and 62%) and β sheet content (5%), 4-helical cytokines functional domains. It has greater number of B-cell epitopes and more complex 3D configuration as compared to MS patients GIT bacterial enzymes.

Conclusion

Present study might enable us to modify the GABAT encoding gene and enzyme through site-directed mutagenesis in pathogenic bacteria thus reducing their potential of causing MS.

Nourishing the Mind: How Food Security Influences Mental Wellbeing

Food insecurity is a significant public health problem worldwide and critical to mental health. There is a complex relationship between food security and mental health. We carried out a narrative review study aiming to address how food insecurity impacts mental wellbeing by focusing on the mental health repercussions of food insecurity, recognizing its pivotal role in attaining Sustainable Development Goals 2 (on hunger) and 3 (on enhancing global wellbeing). A comprehensive search was conducted on PubMed and Google Scholar, incorporating Google searches for pertinent reports and policy documents. To address these questions, we emphasized and elucidated the interconnectedness between food security and mental health. The review shows that food security and mental health share a profound relationship influenced by multifaceted factors like socioeconomic conditions, access to nutritious food, and societal inequalities. We then provide recommendations for integrating food security into mental health strategies based on the insights and conclusions drawn. Strategies ranging from sustainable farming practices to urban agriculture initiatives and digital mental health services demonstrate avenues for enhancing food safety and mental wellbeing. This highlights the need for collaborative interdisciplinary efforts and systemic reforms to address these interconnected challenges.

Potential effects of the most prescribed drugs on the microbiota-gut-brain-axis: A review

The link between drug-induced dysbiosis and its influence on brain diseases through gut-residing bacteria and their metabolites, named the microbiota-gut-brain axis (MGBA), remains largely unexplored. This review investigates the effects of commonly prescribed drugs (metformin, statins, proton-pump-inhibitors, NSAIDs, and anti-depressants) on the gut microbiota, comparing the findings with altered bacterial populations in major brain diseases (depression, multiple sclerosis, Parkinson's and Alzheimer's). The report aims to explore whether drugs can influence the development and progression of brain diseases via the MGBA. Central findings indicate that all explored drugs induce dysbiosis. These dysbiosis patterns were associated with brain disorders. The influence on brain diseases varied across different bacterial taxa, possibly mediated by direct effects or through bacterial metabolites. Each drug induced both positive and negative changes in the abundance of bacteria, indicating a counterbalancing effect. Moreover, the above-mentioned drugs exhibited similar effects, suggesting that they may counteract or enhance each other's effects on brain diseases when taken together by comorbid patients. In conclusion, the interplay of bacterial species and their abundances may have a greater impact on brain diseases than individual drugs or bacterial strains. Future research is needed to better understand drug-induced dysbiosis and the implications for brain disease pathogenesis, with the potential to develop more effective therapeutic options for patients with brain-related diseases.

The effects of intermittent fasting for patients with multiple sclerosis (MS): a systematic review

Some studies have investigated the impact of intermittent fasting (IF) for patients with multiple sclerosis (MS). We aimed to conduct a comprehensive systematic review to analyze and summarize all clinical studies concerning the effects of IF on patients with MS. We conducted an exhaustive review of information available in the Embase, Cochrane, and PubMed databases up until 1 September 2023. All clinical research relating to the impacts of IF for patients with MS were included. In total, this systematic review encompassed 5 studies, which included four RCTs and one pilot study. Each study involved was assessed of high quality. The results from these studies demonstrate that IF protocols could potentially serve as an effective dietary strategy for managing symptoms and improving the quality of life in individuals afflicted with MS. In conclusion, IF might be a potential beneficial dietary intervention for MS. However, the number of trials in this field is relatively limited. The large-scale clinical trials to investigate the effects of IF for MS are urgently needed, which may be helpful to manage this intricate neuroimmune disorder.

Systematic review registration

https://inplasy.com, identifier INPLASY2023100021.

Design and validation of a Questionnaire on the factors influencing self-care behaviors in patients with Multiple sclerosis (QFASMS)

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). Since MS does not have a definitive cure, individuals affected by it need to adapt and coordinate with their chronic illness in order to fulfill their duties and responsibilities. The first step in helping patients to better care for and manage their illness is to engage in self-care behaviors. This study was conducted with the aim of design and validation of a questionnaire on the factors influencing self-care behaviors in patients with Multiple sclerosis.

METHODS

This cross-sectional study was conducted on Multiple sclerosis patients in Iran in 2023. The age range of patients varied between 22 and 52 years. Having MS disease, passing one year of the disease duration, living in Mashhad city, having informed consent to participate in the study and not completing the questionnaire were the entry and exit criteria of the study.

RESULTS

This study was conducted on 500 patients with multiple sclerosis. Based on the results of psychometrics (face, content and construct validity), the number of questions was reduced from 120 to 47 questions and 73 questions were eliminated. Finally, the questionnaire was approved with 47 questions and 4 subscales of understanding the symptoms of the disease (9 questions), tendency to conscious and targeted care (21 questions), laziness in care (8 questions) and tendency to receive therapy services (9 questions). Cronbach's alpha and McDonald's omega index for all questionnaire questions were 0.877 and 0.881, respectively.

CONCLUSIONS

Based on the results of this questionnaire, 47 questions and 4 subscales can be used to measure the factors influencing the adoption of self-care behaviour's in patients with multiple sclerosis.

Diet-microbiome-immune interplay in multiple sclerosis: Understanding the impact of phytoestrogen metabolizing gut bacteria

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS), with both genetic and environmental factors contributing to the pathobiology of the disease. Although HLA genes have emerged as the strongest genetic factor linked to MS, consensus on the environmental risk factors is lacking. Recently, the gut microbiota has garnered increasing attention as a potential environmental factor in MS, as mounting evidence suggests that individuals with MS exhibit microbial dysbiosis (changes in the gut microbiome). Thus, there has been a strong emphasis on understanding the role of the gut microbiome in the pathobiology of MS, specifically, factors regulating the gut microbiota and the mechanism(s) through which gut microbes may contribute to MS. Among all factors, diet has emerged to have the strongest influence on the composition and function of gut microbiota. As MS patients lack gut bacteria capable of metabolizing dietary phytoestrogen, we will specifically discuss the role of a phytoestrogen diet and phytoestrogen metabolizing gut bacteria in the pathobiology of MS. A better understanding of these mechanisms will help to harness the enormous potential of the gut microbiota as potential therapeutics to treat MS and other autoimmune diseases.

Mechanisms underlying the beneficial effects of physical exercise on multiple sclerosis: focus on immune cells

Multiple sclerosis (MS) is a prevalent neuroimmunological illness that leads to neurological disability in young adults. Although the etiology of MS is heterogeneous, it is well established that aberrant activity of adaptive and innate immune cells plays a crucial role in its pathogenesis. Several immune cell abnormalities have been described in MS and its animal models, including T lymphocytes, B lymphocytes, dendritic cells, neutrophils, microglia/macrophages, and astrocytes, among others. Physical exercise offers a valuable alternative or adjunctive disease-modifying therapy for MS. A growing body of evidence indicates that exercise may reduce the autoimmune responses triggered by immune cells in MS. This is partially accomplished by restricting the infiltration of peripheral immune cells into the central nervous system (CNS) parenchyma, curbing hyperactivation of immune cells, and facilitating a transition in the balance of immune cells from a pro-inflammatory to an anti-inflammatory state. This review provides a succinct overview of the correlation between physical exercise, immune cells, and MS pathology, and highlights the potential benefits of exercise as a strategy for the prevention and treatment of MS.

Interaction of the Gut Microbiome and Immunity in Multiple Sclerosis: Impact of Diet and Immune Therapy

The bidirectional communication between the gut and central nervous system (CNS) through microbiota is known as the microbiota-gut-brain axis. The brain, through the enteric neural innervation and the vagus nerve, influences the gut physiological activities (motility, mucin, and peptide secretion), as well as the development of the mucosal immune system. Conversely, the gut can influence the CNS via intestinal microbiota, its metabolites, and gut-homing immune cells. Growing evidence suggests that gut immunity is critically involved in gut-brain communication during health and diseases, including multiple sclerosis (MS). The gut microbiota can influence the development and function of gut immunity, and conversely, the innate and adaptive mucosal immunity can influence microbiota composition. Gut and systemic immunity, along with gut microbiota, are perturbed in MS. Diet and disease-modifying therapies (DMTs) can affect the composition of the gut microbial community, leading to changes in gut and peripheral immunity, which ultimately affects MS. A high-fat diet is highly associated with gut dysbiosis-mediated inflammation and intestinal permeability, while a high-fiber diet/short-chain fatty acids (SCFAs) can promote the development of Foxp3 Tregs and improvement in intestinal barrier function, which subsequently suppress CNS autoimmunity in the animal model of MS (experimental autoimmune encephalomyelitis or EAE). This review will address the role of gut immunity and its modulation by diet and DMTs via gut microbiota during MS pathophysiology.

Probiotic-Derived Ecto-5'-Nucleotidase Produces Anti-Inflammatory Adenosine Metabolites in Treg-Deficient Scurfy Mice

Probiotic Limosilactobacillus reuteri DSM 17938 (DSM 17938) prolongs the survival of Treg-deficient scurfy (SF) mice and reduces multiorgan inflammation by a process requiring adenosine receptor 2A (A2A) on T cells. We hypothesized that L. reuteri-derived ecto-5'-nucleotidase (ecto-5'NT) activity acts to generate adenosine, which may be a central mediator for L. reuteri protection in SF mice. We evaluated DSM 17938-5'NT activity and the associated adenosine and inosine levels in plasma, gut, and liver of SF mice. We examined orally fed DSM 17938, DSM 17938Δ5NT (with a deleted 5'NT gene), and DSM 32846 (BG-R46) (a naturally selected strain derived from DSM 17938). Results showed that DSM 17938 and BG-R46 produced adenosine while "exhausting" AMP, whereas DSM 17938∆5NT did not generate adenosine in culture. Plasma 5'NT activity was increased by DSM 17938 or BG-R46, but not by DSM 17938Δ5NT in SF mice. BG-R46 increased both adenosine and inosine levels in the cecum of SF mice. DSM 17938 increased adenosine levels, whereas BG-R46 increased inosine levels in the liver. DSM 17938Δ5NT did not significantly change the levels of adenosine or inosine in the GI tract or the liver of SF mice. Although regulatory CD73+CD8+ T cells were decreased in spleen and blood of SF mice, these regulatory T cells could be increased by orally feeding DSM 17938 or BG-R46, but not DSM 17938Δ5NT. In conclusion, probiotic-5'NT may be a central mediator of DSM 17938 protection against autoimmunity. Optimal 5'NT activity from various probiotic strains could be beneficial in treating Treg-associated immune disorders in humans.

Identification of commensal gut microbiota signatures as predictors of clinical severity and disease progression in multiple sclerosis

Background

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system and a leading cause of neurological disability in young adults. Clinical presentation and disease course are highly heterogeneous. Typically, disease progression occurs over time and is characterized by the gradual accumulation of disability. The risk of developing MS is driven by complex interactions between genetic and environmental factors, including the gut microbiome. How the commensal gut microbiota impacts disease severity and progression over time remains unknown.

Methods

In a longitudinal study, disability status and associated clinical features in 60 MS patients were tracked over 4.2 ± 0.97 years, and the baseline fecal gut microbiome was characterized via 16S amplicon sequencing. Progressor status, defined as patients with an increase in Expanded Disability Status Scale (EDSS), were correlated with features of the gut microbiome to determine candidate microbiota associated with risk of MS disease progression.

Results

We found no overt differences in microbial community diversity and overall structure between MS patients exhibiting disease progression and non-progressors. However, a total of 45 bacterial species were associated with worsening disease, including a marked depletion in Akkermansia , Lachnospiraceae, and Oscillospiraceae , with an expansion of Alloprevotella , Prevotella-9 , and Rhodospirillales . Analysis of the metabolic potential of the inferred metagenome from taxa associated with progression revealed a significant enrichment in oxidative stress-inducing aerobic respiration at the expense of microbial vitamin K 2 production (linked to Akkermansia ), and a depletion in SCFA metabolism (linked to Lachnospiraceae and Oscillospiraceae ). Further, statistical modeling demonstrated that microbiota composition and clinical features were sufficient to robustly predict disease progression. Additionally, we found that constipation, a frequent gastrointestinal comorbidity among MS patients, exhibited a divergent microbial signature compared with progressor status.

Conclusions

These results demonstrate the utility of the gut microbiome for predicting disease progression in MS. Further, analysis of the inferred metagenome revealed that oxidative stress, vitamin K 2 and SCFAs are associated with progression.

Abstract Figure

Feeding the gut microbiome: impact on multiple sclerosis

Multiple sclerosis (MS) is a multifactorial neurological disease characterized by chronic inflammation and immune-driven demyelination of the central nervous system (CNS). The rising number of MS cases in the last decade could be partially attributed to environmental changes, among which the alteration of the gut microbiome driven by novel dietary habits is now of particular interest. The intent of this review is to describe how diet can impact the development and course of MS by feeding the gut microbiome. We discuss the role of nutrition and the gut microbiota in MS disease, describing preclinical studies on experimental autoimmune encephalomyelitis (EAE) and clinical studies on dietary interventions in MS, with particular attention to gut metabolites-immune system interactions. Possible tools that target the gut microbiome in MS, such as the use of probiotics, prebiotics and postbiotics, are analyzed as well. Finally, we discuss the open questions and the prospects of these microbiome-targeted therapies for people with MS and for future research.

The gut microbiota contributes to the pathogenesis of anorexia nervosa in humans and mice

Anorexia nervosa (AN) is an eating disorder with a high mortality. About 95% of cases are women and it has a population prevalence of about 1%, but evidence-based treatment is lacking. The pathogenesis of AN probably involves genetics and various environmental factors, and an altered gut microbiota has been observed in individuals with AN using amplicon sequencing and relatively small cohorts. Here we investigated whether a disrupted gut microbiota contributes to AN pathogenesis. Shotgun metagenomics and metabolomics were performed on faecal and serum samples, respectively, from a cohort of 77 females with AN and 70 healthy females. Multiple bacterial taxa (for example, Clostridium species) were altered in AN and correlated with estimates of eating behaviour and mental health. The gut virome was also altered in AN including a reduction in viral-bacterial interactions. Bacterial functional modules associated with the degradation of neurotransmitters were enriched in AN and various structural variants in bacteria were linked to metabolic features of AN. Serum metabolomics revealed an increase in metabolites associated with reduced food intake (for example, indole-3-propionic acid). Causal inference analyses implied that serum bacterial metabolites are potentially mediating the impact of an altered gut microbiota on AN behaviour. Further, we performed faecal microbiota transplantation from AN cases to germ-free mice under energy-restricted feeding to mirror AN eating behaviour. We found that the reduced weight gain and induced hypothalamic and adipose tissue gene expression were related to aberrant energy metabolism and eating behaviour. Our 'omics' and mechanistic studies imply that a disruptive gut microbiome may contribute to AN pathogenesis.

Probiotic-derived ecto-5'-nucleotidase produces anti-inflammatory adenosine metabolites in Treg-deficient scurfy mice

Probiotic Limosilactobacillus reuteri DSM 17938 (DSM 17938) prolonges the survival of Treg-deficient scurfy (SF) mice and reduces multiorgan inflammation by a process requiring adenosine receptor 2A (A _2A ) on T cells. We hypothesized that L. reuteri -derived ecto-5'-nucleotidase (ecto-5'NT) activity acts to generate adenosine, which may be a central mediator for L. reuteri protection in SF mice. We evaluated DSM 17938-5'NT activity and the associated adenosine and inosine levels in plasma, gut and liver of SF mice. We examined orally fed DSM 17938, DSM 17938Δ5NT (with a deleted 5'NT gene), and DSM 32846 (BG-R46) (a naturally selected strain derived from DSM 17938). Results showed that DSM 17938 and BG-R46 produced adenosine while "exhausting" AMP, whereas DSM 17938∆5NT did not generate adenosine in culture. Plasma 5'NT activity was increased by DSM 17938 or BG-R46, but not by DSM 17938Δ5NT in SF mice. BG-R46 increased both adenosine and inosine levels in the cecum of SF mice. DSM 17938 increased adenosine levels, whereas BG-R46 increased inosine levels in the liver. DSM 17938Δ5NT did not significantly change the levels of adenosine or inosine in the GI tract or the liver of SF mice. Although regulatory CD73 ⁺ CD8 ⁺ T cells were decreased in spleen and blood of SF mice, these regulatory T cells could be increased by orally feeding DSM 17938 or BG-R46, but not DSM 17938Δ5NT. In conclusion, probiotic-5'NT may be a central mediator of DSM 17938 protection against autoimmunity. Optimal 5'NT activity from various probiotic strains could be beneficial in treating Treg-associated immune disorders in humans.

The Role of Gut Dysbiosis and Potential Approaches to Target the Gut Microbiota in Multiple Sclerosis

It has now been established that a perturbation in gut microbiome composition exists in multiple sclerosis (MS) and its interplay with the immune system and brain could potentially contribute to the development of the disease and influence its course. The effects of the gut microbiota on the disease may be mediated by direct interactions between bacteria and immune cells or through interactions of products of bacterial metabolism with immune and CNS cells. In this review article we summarize the ways in which the gut microbiome of people with MS differs from controls and how bacterial metabolites can potentially play a role in MS pathogenesis, and examine approaches to alter the composition of the gut microbiota potentially alleviating gut dysbiosis and impacting the course of MS.

[Microbiota markers level in the blood and cerebrospinal fluid of patients with different types of multiple sclerosis and radiologically isolated syndrome]

OBJECTIVE

To assess the level of microbiota markers in the blood and cerebrospinal fluid (CSF) of patients with different types of multiple sclerosis (MS), people with radiologically isolated syndrome (RIS) and control subjects.

MATERIAL AND METHODS

We used gas chromatography-mass spectrometry (GC-MS) to evaluate the levels of microbiota markers in 69 patients with different types of MS (27 patients in the acute stage, 35 patients with MS in remission, 7 patients with primary-progressive MS), 10 people with RIS, and 47 control subjects (different diseases of the nervous system of a non-autoimmune or inflammatory nature).

RESULTS

We showed a statistically significant increase in the content of various microbiota markers in the CSF of patients with MS compared with the control group. We found no change in the content of these markers in blood of patients with MS. This suggests a change of markers of microbial load at the level of the central nervous system, but not at the level of the whole organism. The greatest number of statistically significant differences with the control group was found in the content of markers in CSF of patients with MS in remission. In the acute stage, on the contrary, we found no statistically significant differences compared to the control group. In particular, in CSF of patients with MS in remission, a statistically significant increase in the content of bacterial plasmalogen (4.5 times), and increase in the level of microbial markers specific to Peptostreptococcus anaerobius, Pseudomonas aeruginosa, Eubacterium, Bifidobacterium, Butirivibrio, Moraxella, Acinetobacter, Propionibacterium acnes, as well as an increase of markers of the Epstein-Barr virus were found. In addition, there was an increase of campesterol, the likely source of which is campesterol-producing microfungi. In the CSF of subjects with RIS there were a statistically significant increase in the level of markers of the Epstein-Barr virus, Propionibacterium acnes, as well as Pseudomonas, Moraxella, and Acinetobacter.

CONCLUSION

An association of MS with polymicrobial infection is possible. It is also likely that there is a certain pattern of increase of microbiota markers in the CSF of patients with MS, but not in blood.