Administration of bifidobacterium and lactobacillus strains modulates experimental myasthenia gravis and experimental encephalomyelitis in Lewis rats

Mendelian randomization study revealed a gut microbiota-neuromuscular junction axis in myasthenia gravis

A growing number of studies have implicated that gut microbiota abundance is associated with myasthenia gravis (MG). However, the causal relationship underlying the associations is still unclear. Here, we aim to investigate the causal effect of gut microbiota on MG using Mendelian randomization (MR) method. Publicly available Genome-wide association study (GWAS) summary-level data for gut microbiota and for MG were extracted. Inverse variance weighted was used as the main method to analyze causality. The robustness of the results was validated with sensitivity analyses. Our results indicated that genetically predicted increased phylum Lentisphaerae (OR = 1.319, p = 0.026), class Lentisphaerae (OR = 1.306, p = 0.044), order Victivallales (OR = 1.306, p = 0.044), order Mollicutes (OR = 1.424, p = 0.041), and genus Faecalibacterium (OR = 1.763, p = 0.002) were potentially associated with a higher risk of MG; while phylum Actinobacteria (OR = 0.602, p = 0.0124), class Gammaproteobacteria (OR = 0.587, p = 0.036), family Defluviitaleaceae (OR = 0.695, p = 0.047), family Peptococcaceae (OR = 0.698, p = 0.029), and family Family XIII (OR = 0.614, p = 0.017) were related to a lower risk of MG. The present study provides genetic evidence for the causal associations between gut microbiota and MG, thus suggesting novel insights into the gut microbiota-neuromuscular junction axis in the pathogenesis of MG.

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.

Bifidobacterium mechanisms of immune modulation and tolerance

Bifidobacterium is a widely distributed commensal bacterial genus that displays beneficial pro-homeostatic and anti-inflammatory immunomodulatory properties. Depletion or absence of Bifidobacterium in humans and model organisms is associated with autoimmune responses and impaired immune homeostasis. At the cellular level, Bifidobacterium upregulates suppressive regulatory T cells, maintains intestinal barrier function, modulates dendritic cell and macrophage activity, and dampens intestinal Th2 and Th17 programs. While there has been a large volume of literature characterizing the probiotic properties of various Bifidobacterial species, the likely multifactorial mechanisms underlying these effects remain elusive, in particular, its immune tolerogenic effect. However, recent work has shed light on Bifidobacterium surface structural polysaccharide and protein elements, as well as its metabolic products, as commensal mediators of immune homeostasis. This review aims to discuss several mechanisms Bifidobacterium utilizes for immune modulation as well as their indirect impact on the regulation of gut microbiome structure and function, from structural molecules to produced metabolites. These mechanisms are pertinent to an increasingly networked understanding of immune tolerance and homeostasis in health and disease.

Unraveling the Gut-Brain Axis in Multiple Sclerosis: Exploring Dysbiosis, Oxidative Stress, and Therapeutic Insights

This comprehensive review delves into the intricate relationship between the gut microbiota and multiple sclerosis (MS), shedding light on the potential therapeutic avenues for this complex autoimmune disease. It emphasizes the multifactorial nature of MS, including genetic, environmental, and gender-related factors. Furthermore, the article highlights the emerging role of gut microbiota in MS pathophysiology, particularly in terms of gut dysbiosis, oxidative stress, and inflammasome activation within the gut-brain axis. This interplay raises intriguing questions about how the gut microbiota influences the onset and progression of MS. Environmental factors, such as diet and pollutants, add further layers of complexity to the connection between gut health and MS risk. This review also discusses promising therapeutic interventions, such as fecal microbiota transplantation, probiotics, dietary adjustments, and gut-derived metabolites that offer potential avenues for managing MS. It underscores the need for ongoing research to fully unravel the complexities of the role of the gut-brain axis in MS. Ultimately, this article provides a comprehensive exploration of the topic, offering hope for novel preventive and therapeutic strategies that could significantly improve the lives of individuals affected by this challenging autoimmune condition.

Astragaloside IV ameliorates experimental autoimmune myasthenia gravis by regulating CD4 + T cells and altering gut microbiota

BACKGROUND

Myasthenia gravis (MG) is an antibody-mediated autoimmune disease and its pathogenesis is closely related to CD4 + T cells. In recent years, gut microbiota is considered to play an important role in the pathogenesis of MG. Astragaloside IV (AS-IV) is one of the main active components extracted from Astragalus membranaceus and has immunomodulatory effects. To study the immunomodulatory effect of AS-IV and the changes of gut microbiota on experimental autoimmune myasthenia gravis (EAMG) mice, we explore the possible mechanism of AS-IV in improving MG.

METHODS

In this study, network pharmacology was utilized to screen the crucial targets of AS-IV in the treatment of MG. Subsequently, a Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed to identify potential pathways through which AS-IV acts against MG. Furthermore, experimental investigations were conducted to validate the underlying mechanism of AS-IV in MG treatment. Before modeling, 5 mice were randomly selected as the control group (CFA group), and the other 10 were induced to EAMG model. These mice were randomly divided into EAMG group and EAMG + AS-IV group, n = 5/group. In EAMG + AS-IV group, AS-IV was administered by gavage. CFA and EAMG groups were given the same volume of PBS. Body weight, grip strength and clinical symptoms were assessed and recorded weekly. At the last administration, the feces were collected for 16S RNA microbiota analysis. The levels of Treg, Th1 and Th17 cells in spleen and Th1 and Th17 cells in thymus were detected by flow cytometry. The levels of IFN-γ, IL-17 and TGF-β in serum were measured by ELISA. Furthermore, fecal microbial transplantation (FMT) experiments were performed for exploring the influence of changed intestinal flora on EAMG. After EAMG model was induced, the mice were treated with antibiotics daily for 4 weeks to germ-free. Then germ-free EAMG mice were randomly divided into two groups: FMT EAMG group, FMT AS-IV group, n = 3/group. Fecal extractions from EAMG and EAMG + AS-IV groups as gathered above were used to administered daily to the respective groups for 4 weeks. Body weight, grip strength and clinical symptoms were assessed and recorded weekly. The levels of Treg, Th1 and Th17 cells in spleen and Th1 and Th17 cells in thymus were detected at the last administration. The levels of IFN-γ, IL-17 and TGF-β in serum were measured by ELISA.

RESULTS

The network pharmacology and KEGG pathway analysis revealed that AS-IV regulates T cell pathways, including T cell receptor signaling pathway and Th17 cell differentiation, suggesting its potential in improving MG. Further experimental verification demonstrated that AS-IV administration improved muscle strength and body weight, reduced the level of Th1 and Th17 cells, enhanced the level of Treg cells, and resulted in alterations of the gut microbiota, including changes in beta diversity, the Firmicutes/Bacteroidetes (F/B) ratio, and the abundance of Clostridia in EAMG mice. We further conducted FMT tests and demonstrated that the EAMG Abx-treated mice which were transplanted the feces of mice treated with AS-IV significantly alleviated myasthenia symptoms, reduced Th1 and Th17 cells levels, and increased Treg cell levels.

CONCLUSION

This study speculated that AS-IV ameliorates EAMG by regulating CD4 + T cells and altering the structure and species of gut microbiota of EAMG.

Gut microbiota: a new insight into neurological diseases

ABSTRACT

In the last decade, it has become increasingly recognized that a balanced gut microbiota plays an important role in maintaining the health of the host. Numerous clinical and preclinical studies have shown that changes in gut microbiota composition are associated with a variety of neurological diseases, e.g., Parkinson's disease, Alzheimer's disease, and myasthenia gravis. However, the underlying molecular mechanisms are complex and remain unclear. Behavioral phenotypes can be transmitted from humans to animals through gut microbiota transplantation, indicating that the gut microbiota may be an important regulator of neurological diseases. However, further research is required to determine whether animal-based findings can be extended to humans and to elucidate the relevant potential mechanisms by which the gut microbiota regulates neurological diseases. Such investigations may aid in the development of new microbiota-based strategies for diagnosis and treatment and improve the clinical management of neurological disorders. In this review, we describe the dysbiosis of gut microbiota and the corresponding mechanisms in common neurological diseases, and discuss the potential roles that the intestinal microbiome may play in the diagnosis and treatment of neurological disorders.

Microbiota dysbiosis and myasthenia gravis: Do all roads lead to Rome?

Dysregulated immune system with a failure to recognize self from non-self-antigens is one of the common pathogeneses seen in autoimmune diseases. The complex interplay of genetic and environmental factors is important for the occurrence and development of the disease. Among the environmental factors, disturbed gut microbiota (gut dysbiosis) has recently attracted particular attention, especially with advancement in human microbiome research. Although the alterations in microbiota have been seen in various autoimmune diseases, including those of nervous system, there is paucity of information on neuromuscular system diseases. Myasthenia gravis (MG) is one such rare autoimmune disease of neuromuscular junction, and is caused by generation of pathogenic autoantibodies to components of the postsynaptic muscle endplate. In the recent years, accumulating evidences have endorsed the key role of host microbiota, particularly those of gut, in the pathogenesis of MG. Differential microbiota composition, characterized by increased abundance of Fusobacteria, Bacteroidetes, and Proteobacteria, and decreased abundance of Actinobacteria and Firmicutes, has been seen in MG patients in comparison to healthy subjects. Disturbance of microbiota composition, particularly reduced ratio of Firmicutes/Bacteroidetes, alter the gut permeability, subsequently triggering the immunological response. Resultant reduction in levels of short chain fatty acids (SCFAs) is another factor contributing to the immunological response in MG patients. Modulation of gut microbiota via intervention of probiotics, prebiotics, synbiotics, postbiotics (metabiotics), and fecal microbiota transplantation (FMT) is considered to be the futuristic approach for the management of MG. This review summarizes the role of gut microbiota and their metabolites (postbiotics) in the progression of MG. Also, various bacteriotherapeutic approaches involving gut microbiota are discussed for the prevention of MG progression.

The Role of Human Microbiota in Myasthenia Gravis: A Narrative Review

Myasthenia gravis (MG) is an autoimmune neuromuscular disease characterized by fluctuating weakness of the skeletal muscles. Although antibodies against the neuromuscular junction components are recognized, the MG pathogenesis remains unclear, even if with a well-known multifactorial character. However, the perturbations of human microbiota have been recently suggested to contribute to MG pathogenesis and clinical course. Accordingly, some products derived from commensal flora have been demonstrated to have anti-inflammatory effects, while other have been shown to possess pro-inflammatory properties. In addition, patients with MG when compared with age-matched controls showed a distinctive composition in the oral and gut microbiota, with a typical increase in Streptococcus and Bacteroides and a reduction in Clostridia as well as short-chain fatty acid reduction. Moreover, restoring the gut microbiota perturbation has been evidenced after the administration of probiotics followed by an improvement of symptoms in MG cases. To highlight the role of the oral and gut microbiota in MG pathogenesis and clinical course, here, the current evidence has been summarized and reviewed.

The Effect of Aerobic Training With the Consumption of Probiotics on the Myelination of Nerve Fibers in Cuprizone-induced Demyelination Mouse Model of Multiple Sclerosis

Introduction

Extensive human and animal research shows that exercise has beneficial effects on multiple clinical outcomes for patients suffering from multiple sclerosis (MS). This research was conducted to examine the effect of aerobic exercise with probiotic consumption on the myelination of nerve fibers in a cuprizone-induced demyelination mouse model of MS.

Methods

Rats exposed to cuprizone (CPZ) for 13 weeks were subjected to motor and balance tests in week 5. They (5 people in each group) were assigned to five groups of control (C), MS, MS with exercise (MS+Exe), MS with probiotic (MS+Pro), and MS with probiotic and exercise (MS+Pro+Exe) randomly. The exercise groups conducted aerobic exercises 5 days a week for 60 days. The rats received probiotics by gavage. Performance and balance tests were repeated when the eight-week protocol of exercise and probiotic consumption was finished. One day after these interventions, they were sacrificed to undergo biochemical and molecular biology assays.

Results

The results showed that Myelin basic protein (MBP) was increased in the MS+Pro+Exe, MS+Pro, and MS+Exe compared to the MS group (P<0.05).The nestin mRNA showed an increase in MS+Pro+Exe, MS+Exe, and MS+Pro groups compared to the MS group, but this increase was not significant in MS+Pro+Exe and MS+Exe groups compared to the control and MS groups (P>0.05).

Conclusion

According to the results, lifestyle interventions can effectively alleviate demyelinating-inflammatory processes that happen in the brains of MS patients.

Advantages and limitations of experimental autoimmune encephalomyelitis in breaking down the role of the gut microbiome in multiple sclerosis

Since the first model of experimental autoimmune encephalomyelitis (EAE) was introduced almost a century ago, there has been an ongoing scientific debate about the risks and benefits of using EAE as a model of multiple sclerosis (MS). While there are notable limitations of translating EAE studies directly to human patients, EAE continues to be the most widely used model of MS, and EAE studies have contributed to multiple key breakthroughs in our understanding of MS pathogenesis and discovery of MS therapeutics. In addition, insights from EAE have led to a better understanding of modifiable environmental factors that can influence MS initiation and progression. In this review, we discuss how MS patient and EAE studies compare in our learning about the role of gut microbiome, diet, alcohol, probiotics, antibiotics, and fecal microbiome transplant in neuroinflammation. Ultimately, the combination of rigorous EAE animal studies, novel bioinformatic approaches, use of human cell lines, and implementation of well-powered, age- and sex-matched randomized controlled MS patient trials will be essential for improving MS patient outcomes and developing novel MS therapeutics to prevent and revert MS disease progression.

A multistrain probiotic improves handgrip strength and functional capacity in patients with COPD: A randomized controlled trial

PURPOSE

The age-related muscle loss, termed sarcopenia and functional dependency, are common findings in patients with chronic obstructive pulmonary disease (COPD). However, an effective bedside treatment remains elusive.

OBJECTIVE

To assess the effects of probiotics on sarcopenia and physical capacity in COPD patients.

METHODS

Randomized, double-blind, computer-controlled, multicenter trial in two tertiary-care hospitals for 16 weeks. A central computer system randomly allocated male, 63-73 years old COPD patients into placebo (n=53) and probiotic (n=51) groups. The intervention was Vivomix 112 billion*, one capsule a day for 16 weeks. The main outcomes measured were sarcopenia phenotype, short physical performance battery (SPPB), plasma markers of intestinal permeability (zonulin and claudin-3) and neuromuscular junction degradation (CAF22), body composition, and handgrip strength (HGS) before and following the probiotics treatment.

FINDINGS

4 patients discontinued intervention due to poor compliance and 100 patients, including placebo (n=53) and probiotic (n=47) groups were analyzed. Probiotics reduced plasma zonulin, claudin-3, and CAF22, along with an improvement in HGS, gait speed, and SPPB scores (all p<0.05). Probiotic treatment also reduced the plasma c-reactive proteins and 8-isoprostane levels, the markers of systemic inflammation and oxidative stress (p<0.05). Correlation analysis revealed varying degrees of association of plasma biomarkers with sarcopenia indexes. Despite a statistical trend, we did not find a reduction in sarcopenia prevalence in the probiotic group.

CONCLUSION

Taken together, the multistrain probiotic improves muscle strength and functional performance in COPD patients by reducing intestinal permeability and stabilizing neuromuscular junction.

TRIAL REGISTRATION

GMC clinical trial unit, GMC-CREC-00263.

Current understanding of the human microbiome in glioma

There is mounting evidence that the human microbiome is highly associated with a wide variety of central nervous system diseases. However, the link between the human microbiome and glioma is rarely noticed. The exact mechanism of microbiota to affect glioma remains unclear. Recent studies have demonstrated that the microbiome may affect the development, progress, and therapy of gliomas, including the direct impacts of the intratumoral microbiome and its metabolites, and the indirect effects of the gut microbiome and its metabolites. Glioma-related microbiome (gut microbiome and intratumoral microbiome) is associated with both tumor microenvironment and tumor immune microenvironment, which ultimately influence tumorigenesis, progression, and responses to treatment. In this review, we briefly summarize current knowledge regarding the role of the glioma-related microbiome, focusing on its gut microbiome fraction and a brief description of the intratumoral microbiome, and put forward the prospects in which microbiome can be applied in the future and some challenges still need to be solved.

The regulatory effects of lactic acid on neuropsychiatric disorders

Lactic acid is produced mainly in astrocytes in the brain and serves as a substance that supplies energy to neurons. In recent years, numerous studies identified the potential effects of lactic acid on the central nervous system and demonstrated its role in regulating brain function as an energy metabolism substrate or cellular signaling molecule. Both deficiency and accumulation of lactic acid cause neurological dysfunction, which further lead to the development of neuropsychiatric disorders, such as Major depressive disorder, Schizophrenia, Alzheimer's disease, and Multiple sclerosis. Although an association between lactic acid and neuropsychiatric disorders was reported in previous research, the underlying pathogenic mechanisms remain unclear. Therefore, an in-depth understanding of the molecular mechanisms by which lactic acid regulates brain function is of significance for the early diagnosis and prevention of neuropsychiatric disorders. In this review, we summarize evidence that is focused on the potential mechanisms of lactic acid as a signaling molecule involved in the pathogenesis of neuropsychiatric disorders and propose a new mechanism by which lactic acid regulates brain function and disease through the microbiota-gut-brain axis to offer new insight into the prevention and treatment of neuropsychiatric diseases.

Effect of Fufang Huangqi Decoction on the Gut Microbiota in Patients With Class I or II Myasthenia Gravis

Objective

To investigate the effect of Fufang Huangqi Decoction on the gut microbiota in patients with class I or II myasthenia gravis (MG) and to explore the correlation between gut microbiota and MG (registration number, ChiCTR2100048367; registration website, http://www.chictr.org.cn/listbycreater.aspx; NCBI: SRP338707).

Methods

In this study, microbial community composition and diversity analyses were carried out on fecal specimens from MG patients who did not take Fufang Huangqi Decoction (control group, n = 8) and those who took Fufang Huangqi Decoction and achieved remarkable alleviation of symptoms (medication group, n = 8). The abundance, diversity within and between habitats, taxonomic differences and corresponding discrimination markers of gut microbiota in the control group and medicated group were assessed.

Results

Compared with the control group, the medicated group showed a significantly decreased abundance of Bacteroidetes (P < 0.05) and significantly increased abundance of Actinobacteria at the phylum level, a significantly decreased abundance of Bacteroidaceae (P < 0.05) and significantly increased abundance of Bifidobacteriaceae at the family level and a significantly decreased abundance of Blautia and Bacteroides (P < 0.05) and significantly increased abundance of Bifidobacterium, Lactobacillus and Roseburia at the genus level. Compared to the control group, the medicated group had decreased abundance, diversity, and genetic diversity of the communities and increased coverage, but the differences were not significant (P > 0.05); the markers that differed significantly between communities at the genus level and influenced the differences between groups were Blautia, Bacteroides, Bifidobacterium and Lactobacillus.

Conclusions

MG patients have obvious gut microbiota-associated metabolic disorders. Fufang Huangqi Decoction regulates the gut microbiota in patients with class I or II MG by reducing the abundance of Blautia and Bacteroides and increasing the abundance of Bifidobacterium and Lactobacillus. The correlation between gut microbiota and MG may be related to cell-mediated immunity.

Effects of dietary restriction on gut microbiota and CNS autoimmunity

Multiple sclerosis (MS) is the most common central nervous system (CNS) autoimmune disease. It is due to the interplay of genetic and environmental factors. Current opinion is that diet could play a pathogenic role in disease onset and development. Dietary restriction (DR) without malnutrition markedly improves health and increases lifespan in multiple model organisms. DR regimens that utilize continuous or intermittent food restriction can induce anti-inflammatory, immuno-modulatory and neuroendocrine adaptations promoting health. These adaptations exert neuroprotective effects in the main MS animal model, experimental autoimmune encephalomyelitis (EAE). This review summarizes the current knowledge on DR-induced changes in gut microbial composition and metabolite production and its impact on underlying functional mechanisms. Studies demonstrating the protective effects of DR regimens on EAE and people with MS are also presented. This is a rapidly developing research field with important clinical implications for personalized dietary interventions in MS prevention and treatment.

Oral Administration of Probiotic Enterococcus durans to Ameliorate Experimental Autoimmune Encephalomyelitis in Mice

Introduction

Probiotics, including lactobacilli, have immunomodulatory activities with promising effects on inflammatory diseases. In this study, we evaluate the effect of Enterococcus durans (Edu) and three various strains of lactobacilli (Lacto-mix), including L. rhamnosus, L. casei, and L. plantarum, to prevent Experimental Autoimmune Encephalomyelitis (EAE) features.

Methods

C57BL/6 female mice were inoculated with Myelin Oigodendrocyte Glycoprotein (MOG35-55) in CFA (complete Freund's adjuvant) to induce EAE. Five groups (n=6 in each group) of animals received saline or probiotics by oral gavage with 200 μL of lactobacilli (1.5×108 CFU/mL) for 2 weeks before the immunization and during the test for one month.

Results

Histopathological studies showed an increase in infiltration of inflammatory cells and destruction of the myelin membrane in the EAE group but a decrease in inflammatory cells in the probiotic-treated animals. Pro-inflammatory cytokines (Interleukin [IL]-17 and Interferon [IFN]-γ) concentration in the supernatant of the brain and spinal cord tissues showed a significant increase in the EAE compared with the normal saline group (P<0.01). While in the spinal cord tissue, there was a decrease in IL-17 in those animals treated with the Lactomix and Edu + Lacto-mix (P<0.01) and a significant decrease in IFN-γ in those animals that received Edu (P<0.05). Western blot analysis of matrix metalloproteinase-9 and myelin basic protein showed a decrease and increase in treatment and EAE groups, respectively, compared to the normal control group.

Conclusion

Our data suggest that probiotic Enterococcus durans and Lacto-mix prevents EAE, but further studies are needed to clarify the exact mechanisms and their application in preclinical and clinical trials.

Highlights

Dysfunction of the blood-brain barrier, migration of inflammatory cells into the Central Nervous System (CNS), and an increase in the pro-inflammatory factors, are the hallmarks in the pathogenesis of Multiple Sclerosis (MS) and Experimental Autoimmune Encephalomyelitis (EAE).The optimal effects of probiotic strains may involve the simultaneous use of more than one strain.Probiotic Enterococcus durans and Lacto-mix have a preventive effect against EAE.

Plain Language Summary

Multiple Sclerosis (MS) is a myelin-degenerating autoimmune disease in the central nervous system. Experimental Autoimmune Encephalomyelitis (EAE), due to its similar clinical and pathologic features to MS, is widely used in many model studies of this disease. The microbiome refers to a genomic set of germs (bacteria, arches, fungi, and viruses), a commensal flora that lives in the intestine and niche of humans and other mammals. The microbiome affects the host's physiological system, especially the balance between health and disease. Additionally, the importance of the microbiome is evident in regulating the intestine-brain axis, or the coordination of the digestive and the central nervous system. In this regard, probiotics, including lactobacilli, have antioxidant and anti-inflammatory properties in vitro and in vivo. Probiotic strains have a wide range of health-improvement effects, and a combination of strains with specific properties provides a broader range of antimicrobial spectrum and stronger anti-inflammatory effects. Considering the critical role of probiotics in the immune system, this study aimed to investigate the possible role of Enterococcus durans alone or in combination with Lactobacillus mixture (L. rhamnosus, L. casei, and L. plantarum) on the EAE animal model of MS.

The efficacy of probiotics in experimental autoimmune encephalomyelitis (an animal model for MS): a systematic review and meta-analysis

Probiotics immunomodulatory properties and their beneficial effects for diseases such as multiple sclerosis (MS) are reported by several studies. The current systematic review and meta-analysis aimed to investigate the favourable effects of probiotics in improving experimental autoimmune/allergic encephalomyelitis (EAE) as an animal model of MS. We systematically searched Scopus, Web of Sciences (ISI), and PubMed databases to identify relevant studies from the inception of these databases to December 2019. A total of 15 animal studies met the inclusion criteria, while no human study met the inclusion criteria. The association between consumption of probiotics and each sign was calculated using the producing pooled odd ratios (95% confidence interval [95% CI]) in a random effect model. The meta-analysis revealed the significant effect of probiotics on the incidence of EAE, weight gain, and clinical symptoms. However, the effects of probiotics on the duration of the disease varied by probiotic strain. The administration of probiotics was associated with a significant reduction in the risk of mortality only in female animals. Moreover, the meta-analysis revealed the promising effects of probiotics on the prevention and management of EAE.

Targeting the gut to treat multiple sclerosis

The gut-brain axis (GBA) refers to the complex interactions between the gut microbiota and the nervous, immune, and endocrine systems, together linking brain and gut functions. Perturbations of the GBA have been reported in people with multiple sclerosis (pwMS), suggesting a possible role in disease pathogenesis and making it a potential therapeutic target. While research in the area is still in its infancy, a number of studies revealed that pwMS are more likely to exhibit altered microbiota, altered levels of short chain fatty acids and secondary bile products, and increased intestinal permeability. However, specific microbes and metabolites identified across studies and cohorts vary greatly. Small clinical and preclinical trials in pwMS and mouse models, in which microbial composition was manipulated through the use of antibiotics, fecal microbiota transplantation, and probiotic supplements, have provided promising outcomes in preventing CNS inflammation. However, results are not always consistent, and large-scale randomized controlled trials are lacking. Herein, we give an overview of how the GBA could contribute to MS pathogenesis, examine the different approaches tested to modulate the GBA, and discuss how they may impact neuroinflammation and demyelination in the CNS.

Probiotics alleviate depressive behavior in chronic unpredictable mild stress rat models by remodeling intestinal flora

OBJECTIVE

To explore the effects of probiotics on depressive behavior in a chronic unpredictable mild stress (CUMS) rat model by remodeling intestinal flora.

METHODS

Twenty-four male SD rats aged 6-8 weeks were randomly divided into four groups: control group, depression group (CUMS), depression+paroxetine group (Paro) and depression+probiotics group (Pro). Sucrose preference, open field and forced swimming tests were used to assess depression-like behavior in rats. ELISA was used to detect the levels of adrenocorticotropic hormone (ACTH), and corticosterone, norepinephrine and 5-hydroxytryptamine in rat serum. Real-time PCR was used to determine the changes of Lactobacillus, Bifidobacterium, Enterococcus faecalis and Escherichia coli in rat cecum.

RESULTS

Compared with the control group, CUMS led to significant decreases of body weight, total traveled distance, duration in central area, immobility time, norepinephrine and 5-hydroxytryptamine contents in hippocampal tissues, as well as Lactobacillus and Bifidobacterium in the cecum. It also resulted in marked increases of the contents of E. faecalis and E. coli in the cecum, ACTH and corticosterone contents in the serum of rats. Paroxetine and probiotic treatment each diminished or prevented these changes.

CONCLUSION

By remodeling intestinal flora, probiotics can reduce the CUMS-induced depressive behavior of rats, increase the levels of norepinephrine and 5-hydroxytryptamine, and inhibit the expression of ACTH and corticosterone. Significantly, the effect of both paroxetine and probiotic on microorganisms is similar.

Gut microbiota in mental health and depression: role of pre/pro/synbiotics in their modulation

The microbiome residing in the human gut performs a wide range of biological functions. Recently, it has been elucidated that a change in dietary habits is associated with alteration in the gut microflora which results in increased health risks and vulnerability towards various diseases. Falling in line with the same concept, depression has also been shown to increase its prevalence around the globe, especially in the western world. Various research studies have suggested that changes in the gut microbiome profile further result in decreased tolerance of stress. Although currently available medications help in relieving the symptoms of depressive disorders briefly, these drugs are not able to completely reverse the multifactorial pathology of depression. The discovery of the communication pathway between gut microbes and the brain, i.e. the Gut-Brain Axis, has led to new areas of research to find more effective and safer alternatives to current antidepressants. The use of probiotics and prebiotics has been suggested as being effective in various preclinical studies and clinical trials for depression. Therefore, in the present review, we address the new antidepressant mechanisms via gut microbe alterations and provide insight into how these can provide an alternative to antidepressant therapy without the side effects and risk of adverse drug reactions.

Temozolomide-Induced Changes in Gut Microbial Composition in a Mouse Model of Brain Glioma

Background

Gut microbiota is associated with the progression of brain tumors. However, the alterations in gut microbiota observed during glioma growth and temozolomide (TMZ) therapy remain poorly understood.

Methods

C57BL/6 male mice were implanted with GL261 glioma cells. TMZ/sodium carboxymethyl cellulose (SCC) was administered through gavage for five consecutive days (from 8 to 12 days after implantation). Fecal samples were collected before (T0) and on days 7 (T1), 14 (T2), and 28 (T3) after implantation. The gut microbiota was analyzed using 16S ribosomal DNA sequencing followed by absolute and relative quantitation analyses.

Results

Nineteen genera were altered during glioma progression with the most dramatic changes in Firmicutes and Bacteroidetes phyla. During glioma growth, Lactobacillus abundance decreased in the early stage (T1) and then gradually increased (T2, T3); Intestinimonas abundance exhibited a persistent increase; Anaerotruncus showed a transient increase (T2) and then a subsequent decrease (T3). Similar longitudinal changes in Intestinimonas and Anaerotruncus abundance were observed in TMZ-treated mice, but the decrease of Anaerotruncus at T3 in the TMZ-treated group was less than that in the vehicle-treated group. No significant change in Lactobacillus was observed after TMZ treatment. Additionally, compared to vehicle control, TMZ treatment led to an enrichment in Akkermansia and Bifidobacterium.

Conclusion

Glioma development and progression altered the composition of gut microbiota. Induction of Akkermansia and Bifidobacterium as well as the prevention of the reduction in Anaerotruncus may contribute to the anti-tumor effect of TMZ. This study helps to reveal the association between levels of specific microbial species in the gut and the anti-tumor effect of TMZ.

Efficacy of probiotics in multiple sclerosis: a systematic review of preclinical trials and meta-analysis of randomized controlled trials

Preliminary evidence shows the potential role of probiotics in ameliorating multiple sclerosis (MS); however, the effects of probiotics on MS remain unclear.

Probiotic and commensal gut microbial therapies in multiple sclerosis and its animal models: a comprehensive review

The need for alternative treatments for multiple sclerosis (MS) has triggered copious amounts of research into microbial therapies focused on manipulating the microbiota-gut-brain axis. This comprehensive review was intended to present and systematically evaluate the current clinical and preclinical evidence for various probiotic and commensal gut microbial therapies as treatments for MS, using the Bradford Hill criteria (BHC) as a multi-parameter assessment rubric. Literature searches were performed to identify a total of 37 relevant studies (6 human, 31 animal), including 28 probiotic therapy and 9 commensal therapy studies. In addition to presenting qualitative summaries of these findings, therapeutic evidence for each bacterial formulation was assessed using the BHC to generate summative scores. These scores, which encompassed study quality, replication, and other considerations, were used to rank the most promising therapies and highlight deficiencies. Several therapeutic formulations, including VSL#3, Lactobacillus paracasei, Bifidobacterium animalis, E. coli Nissle 1917, and Prevotella histicola, emerged as the most promising. In contrast, a number of other therapies were hindered by limited evidence of replicable findings and other criteria, which need to be addressed by future studies in order to harness gut microbial therapies to ultimately provide cheaper, safer, and more durable treatments for MS.

A Commercial Probiotic Induces Tolerogenic and Reduces Pathogenic Responses in Experimental Autoimmune Encephalomyelitis

Previous studies in experimental autoimmune encephalomyelitis (EAE) models have shown that some probiotic bacteria beneficially impact the development of this experimental disease. Here, we tested the therapeutic effect of two commercial multispecies probiotics—Lactibiane iki and Vivomixx—on the clinical outcome of established EAE. Lactibiane iki improves EAE clinical outcome in a dose-dependent manner and decreases central nervous system (CNS) demyelination and inflammation. This clinical improvement is related to the inhibition of pro-inflammatory and the stimulation of immunoregulatory mechanisms in the periphery. Moreover, both probiotics modulate the number and phenotype of dendritic cells (DCs). Specifically, Lactibiane iki promotes an immature, tolerogenic phenotype of DCs that can directly induce immune tolerance in the periphery, while Vivomixx decreases the percentage of DCs expressing co-stimulatory molecules. Finally, gut microbiome analysis reveals an altered microbiome composition related to clinical condition and disease progression. This is the first preclinical assay that demonstrates that a commercial probiotic performs a beneficial and dose-dependent effect in EAE mice and one of the few that demonstrates a therapeutic effect once the experimental disease is established. Because this probiotic is already available for clinical trials, further studies are being planned to explore its therapeutic potential in multiple sclerosis patients.

Osteopontin exacerbates the progression of experimental autoimmune myasthenia gravis by affecting the differentiation of T cell subsets

Osteopontin (OPN) is a multifunctional extracellular matrix phosphoprotein that has a specific and complicated structure, and contributes to numerous physiological and pathological activities. The mechanism of OPN in many diseases has been confirmed; however, the role of OPN in myasthenia gravis (MG) remains unclear. In this study, we recombined rat OPN protein in vitro, and assessed how OPN affects the development of autoimmunity using an experimental autoimmune myasthenia gravis (EAMG) rat model. The results showed that the concentration of OPN in serum was up-regulated. Both mRNA and protein levels in splenocytes increased in the EAMG model. OPN treatment in vitro strongly promoted the differentiation of Th1 cells, and inhibited the differentiation of Treg cells. Intraperitoneal injection of OPN revealed the early incidence of EAMG, and more serious disease. This effect was accompanied by an increased percentage of Th1 cells. In conclusion, OPN likely exacerbates the pathogenesis of EAMG by promoting the differentiation of Th1 cells and inhibiting the differentiation of Treg cells.

Streptococcus thermophilus ST285 Alters Pro-Inflammatory to Anti-Inflammatory Cytokine Secretion against Multiple Sclerosis Peptide in Mice

Probiotic bacteria have beneficial effects to the development and maintenance of a healthy microflora that subsequently has health benefits to humans. Some of the health benefits attributed to probiotics have been noted to be via their immune modulatory properties suppressing inflammatory conditions. Hence, probiotics have become prominent in recent years of investigation with regard to their health benefits. As such, in the current study, we determined the effects of Streptococcus thermophilus to agonist MBP_83-99 peptide immunized mouse spleen cells. It was noted that Streptococcus thermophilus induced a significant increase in the expression of anti-inflammatory IL-4, IL-5, IL-10 cytokines, and decreased the secretion of pro-inflammatory IL-1β and IFN-γ Regular consumption of Streptococcus thermophilus may therefore be beneficial in the management and treatment of autoimmune diseases such as multiple sclerosis.

Therapeutic Effect of Bifidobacterium Administration on Experimental Autoimmune Myasthenia Gravis in Lewis Rats

Beneficial effects of probiotics on gut microbiota homeostasis and inflammatory immune responses suggested the investigation of their potential clinical efficacy in experimental models of autoimmune diseases. Indeed, administration of two bifidobacteria and lactobacilli probiotic strains prevented disease manifestations in the Lewis rat model of Myasthenia Gravis (EAMG). Here, we demonstrate the clinical efficacy of therapeutic administration of vital bifidobacteria (i.e., from EAMG onset). The mechanisms involved in immunomodulation were investigated with ex vivo and in vitro experiments. Improvement of EAMG symptoms was associated to decreased anti-rat AChR antibody levels, and differential expression of TGFβ and FoxP3 immunoregulatory transcripts in draining lymph nodes and spleen of treated-EAMG rats. Exposure of rat bone marrow-derived dendritic cells to bifidobacteria or lactobacilli strains upregulated toll-like receptor 2 mRNA expression, a key molecule involved in bacterium recognition via lipotheicoic acid. Live imaging experiments of AChR-specific effector T cells, co-cultured with BMDCs pre-exposed to bifidobacteria, demonstrated increased percentages of motile effector T cells, suggesting a hindered formation of TCR-peptide-MHC complex. Composition of gut microbiota was studied by 16S rRNA gene sequencing, and α and β diversity were determined in probiotic treated EAMG rats, with altered ratios between Tenericutes and Verrucomicrobia (phylum level), and Ruminococcaceae and Lachnospiraceae (family level). Moreover, the relative abundance of Akkermansia genus was found increased compared to healthy and probiotic treated EAMG rats. In conclusion, our findings confirms that the administration of vital bifidobacteria at EAMG onset has beneficial effects on disease progression; this study further supports preclinical research in human MG to evaluate probiotic efficacy as supplementary therapy in MG.

Lactobacillus reuteri Reduces the Severity of Experimental Autoimmune Encephalomyelitis in Mice by Modulating Gut Microbiota

The gut microbiome plays an important role in immune function and has been implicated in multiple sclerosis (MS). However, how and if the modulation of microbiota can prevent or treat MS remain largely unknown. In this study, we showed that probiotic Lactobacillus reuteri DSM 17938 (L. reuteri) ameliorated the development of murine experimental autoimmune encephalomyelitis (EAE), a widely used animal model of MS, a model which is primarily mediated by T_H17 and T_H1 cells. We discovered that L. reuteri treatment reduced T_H1/T_H17 cells and their associated cytokines IFN-γ/IL-17 in EAE mice. We also showed that the loss of diversity of gut microbiota induced by EAE was largely restored by L. reuteri treatment. Taxonomy-based analysis of gut microbiota showed that three “beneficial” genera Bifidobacterium, Prevotella, and Lactobacillus were negatively correlated with EAE clinical severity, whereas the genera Anaeroplasma, Rikenellaceae, and Clostridium were positively correlated with disease severity. Notably, L. reuteri treatment coordinately altered the relative abundance of these EAE-associated taxa. In conclusion, probiotic L. reuteri changed gut microbiota to modulate immune responses in EAE, making it a novel candidate in future studies to modify the severity of MS.

Immunomodulatory effects of probiotics: Can they be used to treat allergies and autoimmune diseases?

As a person ages, physiological, immunological and gut microbiome changes collectively result in an array of chronic conditions. According to the 'hygiene hypothesis' the increasing prevalence of immune-mediated disorders may be related to intestinal dysbiosis, leading to immune dysfunction and associated conditions such as eczema, asthma, allergies and autoimmune diseases. Beneficial probiotic bacteria can be utilized by increasing their abundance within the gastrointestinal lumen, which in turn will modulate immune cells, such as, T helper (Th)-1, Th2, Th17, regulatory T (Treg) cells and B cells, which have direct relevance to human health and the pathogenesis of immune disorders. Here, we describe the cross-talk between probiotics and the gastrointestinal immune system, and their effects in relation to inflammatory bowel disease, multiple sclerosis, allergies and atopic dermatitis.

Oral Probiotics Ameliorate the Behavioral Deficits Induced by Chronic Mild Stress in Mice via the Gut Microbiota-Inflammation Axis

In recent years, a burgeoning body of research has revealed links between depression and the gut microbiota, leading to the therapeutic use of probiotics for stress-related disorders. In this study, we explored the potential antidepressant efficacy of a multi-strain probiotics treatment (Lactobacillus helveticus R0052, Lactobacillus plantarum R1012, and Bifidobacterium longum R0175) in a chronic mild stress (CMS) mouse model of depression and determined its probable mechanism of action. Our findings revealed that mice subjected to CMS exhibited anxiety- and depressive-like behaviors in the sucrose preference test, elevated plus maze, and forced swim test, along with increased interferon-γ, tumor necrosis factor-α, and indoleamine 2,3-dioxygenase-1 levels in the hippocampus. Moreover, the microbiota distinctly changed from the non-stress group and was characterized by highly diverse bacterial communities associated with significant reductions in Lactobacillus species. Probiotics attenuated CMS-induced anxiety- and depressive-like behaviors, significantly increased Lactobacillus abundance, and reversed the CMS-induced immune changes in the hippocampus. Thus, the possible mechanism involved in the antidepressant-like activity of probiotics is correlated with Lactobacillus species via the gut microbiota-inflammation-brain axis.