Department of Child Health and Development, Graduate School of Medical and Dental Sciences , Tokyo Medical and Dental University (TMDU) , Tokyo , Japan
Inflammatory bowel diseases and primary immunodeficiency diseases.
Recent advances in molecular biology have provided important insights into the genetic background of various inflammatory diseases. In particular, genome-wide association studies of inflammatory diseases have revealed genetic loci that play critical roles in the pathology of inflammation. Whole-exome and whole-genome sequencing analyses have also identified more than 300 causative genes for primary immunodeficiency diseases (PIDs). Some genetic loci that are associated with inflammatory diseases are mutated in PIDs, suggesting close relationships between inflammation and PIDs. Inflammatory diseases for which genetic associations have been described include inflammatory bowel disease (IBD), multiple sclerosis, rheumatoid arthritis, type 1 diabetes mellitus, and systemic lupus erythematosus. Herein, I discuss about the genetic interactions between IBD and PIDs.
Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India
Gut microbiota in neurodegenerative disorders.
Gut dysbiosis, a primary factor behind various gastrointestinal disorders may also augment lipopolysaccharides, pro-inflammatory cytokines, T helper cells and monocytes causing increased intestinal and BBB permeability via microbiota-gut-brain axis. Consequentially, accumulation of misfolded proteins, axonal damage and neuronal demyelination sets in, thus facilitating the pathogenesis of neurodegenerative disorders like Parkinson's disease, Alzheimer's disease, multiple sclerosis and amyotrophic lateral sclerosis. Studies revealed that intake of probiotics may help in the integrity of intestinal and BBB thus ameliorating the above neurodegenerative disorders. This review summarizes the current understanding of the role of gut microbiota in neurodegenerative disorders and possible intervention strategies.
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Department of Immunology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo, Japan
Gut microbiota-dependent CCR9+CD4+ T cells are altered in secondary progressive multiple sclerosis.
The mechanism underlying the progression of relapsing-remitting multiple sclerosis to secondary progressive multiple sclerosis (SPMS), characterized by accumulating fixed disability, is yet to be fully understood. Although alterations in the gut microbiota have recently been highlighted in multiple sclerosis pathogenesis, the mechanism linking the altered gut environment with the remote CNS pathology remains unclear. Here, we analyse human CD4+ memory T cells expressing the gut-homing chemokine receptor CCR9 and found a reduced frequency of CCR9+ memory T cells in the peripheral blood of patients with SPMS relative to healthy controls. The reduction in the proportion of CCR9+ cells among CD4+ memory T cells (%CCR9) in SPMS did not correlate with age, disease duration or expanded disability status scale score, although %CCR9 decreased linearly with age in healthy controls. During the clinical relapse of both, relapsing-remitting multiple sclerosis and neuromyelitis optica, a high proportion of cells expressing the lymphocyte activating 3 gene (LAG3) was detected among CCR9+ memory T cells isolated from the CSF, similar to that observed for mouse regulatory intraepithelial lymphocytes. In healthy individuals, CCR9+ memory T cells expressed higher levels of CCR6, a CNS-homing chemokine receptor, and exhibited a regulatory profile characterized by both the expression of C-MAF and the production of IL-4 and IL-10. However, in CCR9+ memory T cells, the expression of RORγt was specifically upregulated, and the production of IL-17A and IFNγ was high in patients with SPMS, indicating a loss of regulatory function. The evaluation of other cytokines supported the finding that CCR9+ memory T cells acquire a more inflammatory profile in SPMS, reporting similar aspects to CCR9+ memory T cells of the elderly healthy controls. CCR9+ memory T cell frequency decreased in germ-free mice, whereas antibiotic treatment increased their number in specific pathogen-free conditions. Here, we also demonstrate that CCR9+ memory T cells preferentially infiltrate into the inflamed CNS resulting from the initial phase and that they express LAG3 in the late phase in the experimental autoimmune encephalomyelitis mouse model of multiple sclerosis. Antibiotic treatment reduced experimental autoimmune encephalomyelitis symptoms and was accompanied by an increase in CCR9+ memory T cells in the peripheral blood. Antibodies against mucosal vascular addressin cell adhesion molecule 1 (MADCAM1), which is capable of blocking cell migration to the gut, also ameliorated experimental autoimmune encephalomyelitis. Overall, we postulate that the alterations in CCR9+ memory T cells observed, caused by either the gut microbiota changes or ageing, may lead to the development of SPMS.
Department of human medicine, University of Zurich, Switzerland
Brain Aging and Gut⁻Brain Axis.
In the last decade, the microbiome in general and the gut microbiome in particular have been associated not only to brain development and function, but also to the pathophysiology of brain aging and to neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), depression, or multiple sclerosis (MS) ..
Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester
Microbiome, Immunomodulation, and the Neuronal System.
Vertebrates harbor both symbiotic and pathogenic bacteria on the body and various mucosal surfaces. Of these surfaces, the intestine has the most diverse composition. This composition is dependent upon various environmental and genetic factors, with diet exerting the maximum influence. Significant roles of the intestinal bacteria are to stimulate the development of a competent mucosal immune system and to maintain tolerance within the intestine. One manner in which this is achieved is by the establishment of epithelial integrity by microbiota found in healthy individuals (healthy microbiota); however, in the case of a disrupted intestinal microbiome (dysbiosis), which can be caused by various conditions, the epithelial integrity is compromised. This decreased epithelial integrity can then lead to luminal products crossing the barrier, generating a systemic proinflammatory response. In addition to epithelial integrity, healthy intestinal commensals metabolize indigestible dietary substrates and produce short-chain fatty acids, which are bacterial metabolites that are essential for colonic health and regulating the function of the intestinal immune system. Intestinal commensals are also capable of producing neuroactive molecules and neurotransmitters that can affect the function of the vagus nerve. The observations that intestinal dysbiosis is associated with different diseases of the nervous system, suggests that cross-talk occurs amongst the gut, the nervous system, and the immune system.
Free full text. https://www.ncbi.nlm.nih.gov/pmc/articl ... le_601.pdf
Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medic, Japan
Intestinal microbiome as a novel therapeutic target for local and systemic inflammation.
Recently, the pathogenesis of systemic inflammatory disease such as inflammatory bowel disease (IBD), multiple sclerosis (MS), systemic inflammatory arthritis, asthma, and non-alcoholic fatty liver disease has been reported to be related to the dysbiosis of gut microbiota. The contribution of special bacteria for the development of those diseases has been elucidated by disease animal models such as germ-free mice. Besides, the contribution by several bacteria for the pathogenesis of those diseases has been suggested by detailed analysis of the 16 small ribosomal subunit RNA (16S rRNA) from stool samples of the patients. Gut microbiota-targeted treatment for systemic inflammatory diseases such as fecal microbiota transplant (FMT), and probiotics has been now reported. Though there are several issues to be understood, these treatments have been highlighted as an innovative approach to intractable systemic inflammatory disease. In the present review, recent reports regarding the relation between gut microbiota and systemic inflammatory diseases are discussed with treatments to target gut microbiota.
Division of Gastroenterology, Departments of Pediatrics, The University of Texas Health Science Center at Houston-McGovern Medical School, Houston
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 TH17 and TH1 cells. We discovered that L. reuteri treatment reduced TH1/TH17 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.
They forget one crucial step between the microbiome and the immune response.Petr75 wrote: ↑Sun Dec 16, 2018 3:45 am2018 Nov 6
UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, California
Multiple Sclerosis-Associated Changes in the Composition and Immune Functions of Spore-Forming Bacteria
PMC Article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6222044/
... We specifically show that while small differences exist between the microbiomes of MS patients and healthy subjects, these differences are exacerbated in the chloroform-resistant fraction. We further demonstrate that, when purified from MS patients, this fraction is correlated with impaired immunomodulatory responses in vitro.
The issue is that a bad gut leads to a failure in epigenetic regulation and cells come to expression.
At that point, there is cross reaction between B cells and endothelial cells because of common epitopes.
Often herpes will underly; the mechanism is called autoimmunity.
Petr75 wrote: ↑Mon Dec 17, 2018 11:22 pm2018 Nov 10
Servicio de Neurología. Hospital San Pedro, Logroño, La Rioja, España
Disease of the holobiont, the example of multiple sclerosis
... It is also well documented that there are differences in the microbiota of patients with MS that are associated with a different expression of genes related to inflammation.
see also viewtopic.php?f=1&t=15188&start=885#p257234
Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
Bowel symptoms predate the diagnosis among many patients with multiple sclerosis: A 14-year cohort study
Multiple sclerosis (MS) is an autoimmune, neurodegenerative disease frequently complicated by bowel symptoms. Multiple sclerosis typically first manifests with a demyelination event, also known as a clinically isolated syndrome (CIS). We sought to examine the prevalence of prodromal bowel symptoms predating a CIS in patients with MS as part of a recently characterized prodromal phase of disease.
We constructed a retrospective cohort of MS patients with bowel symptoms and an identifiable CIS at two tertiary care centers over 14 years using administrative and billing data. We determined the date of onset of reported bowel symptoms in comparison with the date of first CIS and determined the overall prevalence of prediagnosis bowel symptoms within 1, 2, 3, and >3 years from a CIS. We used multivariable modeling to determine demographic and clinical risk factors for prediagnosis bowel symptoms.
Among 385 MS patients with reported bowel symptoms, 122 (31.6%) reported bowel symptoms prior to CIS. The most common first bowel symptom was constipation (50.0%), followed by diarrhea (29.5%). The average lead time between a first bowel symptom and a CIS event was 3.7 ± 3.4 years. Pre-CIS fatigue (OR 4.48, 95% CI: 2.68-7.51, P < 0.001) and pre-CIS sensory disturbances (OR 1.88, 95% CI: 1.15-3.08, P < 0.05) were all associated with bowel symptoms prior to a CIS event.
CONCLUSIONS AND INFERENCES:
Nearly a third of MS patients with bowel symptoms reported bowel symptoms prior to a demyelinating event/CIS. Characterization of a prodromal phase of disease may provide important insights into understanding disease progression.
Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
Dietary Modulation of Intestinal Microbiota: Future Opportunities in Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis.
Multiple sclerosis (MS) is an autoimmune disease that affects the functioning of the central nervous system (CNS). Recent studies on MS and its animal model, experimental autoimmune encephalomyelitis (EAE), have shown that the composition and abundance of microbes in the intestinal microbiota are an environmental risk factor for the development of MS and EAE. Changes in certain microbial populations in the gastrointestinal tract can cause MS in humans, but MS inflammation can be reduced or even prevented by introducing other commensal microbes that produce beneficial metabolites. Other risk factors for MS include the presence of an altered gut physiology and the interaction between the intestinal microbiota and the immune system. Metabolites including short-chain fatty acids (SCFAs), such as butyrate, are the primary signaling molecules produced by the intestinal microbiota that interact with the host immune system, suggesting an association between MS pathophysiology and gut microbiota. In addition, several host microRNAs present in the gut have been found to interact with the intestinal microbial community, these interactions may indirectly affect the neurological system. Increasing evidence has shown that regulation of the intestinal microbiota is an important approach for reducing MS inflammation. Thus, here we review the use of diet to alter the gut microbiota and its application in the treatment and prevention of MS.
Department of Pathology, Microbiology and Immunology, University of South Carolina, School of Medicine, Columbia
The role of gut microbiota in shaping the relapse-remitting and chronic-progressive forms of multiple sclerosis in mouse models.
Using a mouse model of multiple sclerosis (MS), experimental autoimmune encephalitis (EAE), we evaluated the role of gut microbiota in modulating chronic-progressive (CP) versus relapse-remitting (RR) forms of the disease. We hypothesized that clinical courses of EAE may be shaped by differential gut microbiota. Metagenomic sequencing of prokaryotic 16S rRNA present in feces from naïve mice and those exhibiting CP-EAE or RR-EAE revealed significantly diverse microbial populations. Microbiota composition was considerably different between naïve strains of mice, suggesting microbial components present in homeostatic conditions may prime mice for divergent courses of disease. Additionally, there were differentially abundant bacteria in CP and RR forms of EAE, indicating a potential role for gut microbiota in shaping tolerant or remittance-favoring, and pathogenic or pro-inflammatory-promoting conditions. Furthermore, immunization to induce EAE led to significant alterations in gut microbiota, some were shared between disease courses and others were course-specific, supporting a role for gut microbial composition in EAE pathogenesis. Moreover, using Linear Discriminant Analysis (LDA) coupled with effect size measurement (LEfSe) to analyze microbial content, biomarkers of each naïve and disease states were identified. Our findings demonstrate for the first time that gut microbiota may determine the susceptibility to CP or RR forms of EAE.
Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Georg-August-Universität Göttingen, Göttingen, Germany
Modification of the gut microbiome to combat neurodegeneration.
The gut microbiome was extensively researched for its biological variety and its potential role in propagating diseases outside of the gastrointestinal (GI) tract. Recently, a lot of effort was focused on comprehending the gut-brain axis and the bizarre communication between the GI system and the nervous system. Ample amount of studies being carried out also revealed the involvement of the gut microbiome in enhancing the degree of many neurological disorders, including neurodegenerative diseases. It was widely observed that there were distinct microbiome profiles and dysbiosis within patients suffering from Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. Various approaches to re-establish the balance of the gut microbiome, from antibiotic therapy, fecal microbiota transplant, or ingestion of psychobiotics, are discussed within this review within the specific context of combating neurodegenerative diseases. Present studies and clinical trials indicate that although there is an immense potential of gut microbiome modification to be preventive or therapeutic, there are still many intercalated components of the gut-brain axis at play and thus, more research needs to be carried out to delineate microbiome factors that may potentially alleviate symptoms of neurodegeneration.
Multiple Sclerosis Centre, Department of Neurology, Third Affiliated Hospital, Sun Yat-sen University, China
Gut dysbiosis and lack of short chain fatty acids in a Chinese cohort of patients with multiple sclerosis.
Recent studies, mostly conducted in Western countries, showed that gut microbes are involved in the pathogenesis of multiple sclerosis (MS).
The aim of this study was to investigate whether gut dysbiosis is relevant to the initiation and progression of MS in a Chinese population.
Next-generation sequencing (NGS) and gas chromatography (GC) were integrated and used to compare the fecal bacterial communities and the short-chain fatty acid (SCFA) levels among relapsing-remitting MS (RRMS) patients (n = 34), neuromyelitis optica spectrum disorder (NMOSD) patients (n = 34), and healthy controls (HCs) (n = 34). T-cell profile analyses were performed by flow cytometry for MS patients and matched controls (n = 12).
The gut microbiome of MS patients was characterized by an increase of Streptococcus and a decrease of Prevotella_9; additionally, compared to NMOSD patients, Prevotella 9 was found to be much more abundant in MS patients. (2) A striking depletion of fecal acetate, propionate, and butyrate was observed in MS patients compared to HCs. (3) The abundance of Streptococcus was negatively correlated with the proportion of pTregs (P < 0.05) and positively correlated with Th17 cells (P < 0.05) in the peripheral blood, while the abundance of Prevotella_9 was negatively correlated with the Th17 cell frequency (P < 0.01), and the fecal SCFA level was positively correlated with pTreg frequency (P < 0.05).
Gut dysbiosis and a lack of SCFAs exist in Chinese MS patients, which might be related to an aberrant immune response of MS; this relationship may have a diagnostic and therapeutic value for patients with MS.
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