The gastrointestinal microbiota in the development of ME/CFS: a critical view and potential perspectives.

Like other infections, a SARS-CoV-2 infection can also trigger Post-Acute Infection Syndromes (PAIS), which often progress into myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS, characterized by post-exercise malaise (PEM), is a severe multisystemic disease for which specific diagnostic markers or therapeutic concepts have not been established. Despite numerous indications of post-infectious neurological, immunological, endocrinal, and metabolic deviations, the exact causes and pathophysiology remain unclear. To date, there is a paucity of data, that changes in the composition and function of the gastrointestinal microbiota have emerged as a potential influencing variable associated with immunological and inflammatory pathways, shifts in ME/CFS. It is postulated that this dysbiosis may lead to intestinal barrier dysfunction, translocation of microbial components with increased oxidative stress, and the development or progression of ME/CFS. In this review, we detailed discuss the findings regarding alterations in the gastrointestinal microbiota and its microbial mediators in ME/CFS. When viewed critically, there is currently no evidence indicating causality between changes in the microbiota and the development of ME/CFS. Most studies describe associations within poorly defined patient populations, often combining various clinical presentations, such as irritable bowel syndrome and fatigue associated with ME/CFS. Nevertheless, drawing on analogies with other gastrointestinal diseases, there is potential to develop strategies aimed at modulating the gut microbiota and/or its metabolites as potential treatments for ME/CFS and other PAIS. These strategies should be further investigated in clinical trials.

Metabolic and inflammatory perturbation of diabetes associated gut dysbiosis in people living with and without HIV infection.

BACKGROUND: Gut dysbiosis has been linked with both HIV infection and diabetes, but its interplay with metabolic and inflammatory responses in diabetes, particularly in the context of HIV infection, remains unclear. METHODS: We first conducted a cross-sectional association analysis to characterize the gut microbial, circulating metabolite, and immune/inflammatory protein features associated with diabetes in up to 493 women (~ 146 with prevalent diabetes with 69.9% HIV +) of the Women's Interagency HIV Study. Prospective analyses were then conducted to determine associations of identified metabolites with incident diabetes over 12 years of follow-up in 694 participants (391 women from WIHS and 303 men from the Multicenter AIDS Cohort Study; 166 incident cases were recorded) with and without HIV infection. Mediation analyses were conducted to explore whether gut bacteria-diabetes associations are explained by altered metabolites and proteins. RESULTS: Seven gut bacterial genera were identified to be associated with diabetes (FDR-q < 0.1), with positive associations for Shigella, Escherichia, Megasphaera, and Lactobacillus, and inverse associations for Adlercreutzia, Ruminococcus, and Intestinibacter. Importantly, the associations of most species, especially Adlercreutzia and Ruminococcus, were largely independent of antidiabetic medications use. Meanwhile, 18 proteins and 76 metabolites, including 3 microbially derived metabolites (trimethylamine N-oxide, phenylacetylglutamine (PAGln), imidazolepropionic acid (IMP)), 50 lipids (e.g., diradylglycerols (DGs) and triradylglycerols (TGs)) and 23 non-lipid metabolites, were associated with diabetes (FDR-q < 0.1), with the majority showing positive associations and more than half of them (59/76) associated with incident diabetes. In mediation analyses, several proteins, especially interleukin-18 receptor 1 and osteoprotegerin, IMP and PAGln partially mediate the observed bacterial genera-diabetes associations, particularly for those of Adlercreutzia and Escherichia. Many diabetes-associated metabolites and proteins were altered in HIV, but no effect modification on their associations with diabetes was observed by HIV. CONCLUSION: Among individuals with and without HIV, multiple gut bacterial genera, blood metabolites, and proinflammatory proteins were associated with diabetes. The observed mediated effects by metabolites and proteins in genera-diabetes associations highlighted the potential involvement of inflammatory and metabolic perturbations in the link between gut dysbiosis and diabetes in the context of HIV infection.

Microbial Dynamics in Ophthalmic Health: Exploring the Interplay between Human Microbiota and Glaucoma Pathogenesis.

The human microbiome has a crucial role in the homeostasis and health of the host. These microorganisms along with their genes are involved in various processes, among these are neurological signaling, the maturation of the immune system, and the inhibition of opportunistic pathogens. In this sense, it has been shown that a healthy ocular microbiota acts as a barrier against the entry of pathogens, contributing to the prevention of infections. In recent years, a relationship has been suggested between microbiota dysbiosis and the development of neurodegenerative diseases. In patients with glaucoma, it has been observed that the microbiota of the ocular surface, intraocular cavity, oral cavity, stomach, and gut differ from those observed in healthy patients, which may suggest a role in pathology development, although the evidence remains limited. The mechanisms involved in the relationship of the human microbiome and this neurodegenerative disease remain largely unknown. For this reason, the present review aims to show a broad overview of the influence of the structure and composition of the human oral and gut microbiota and relate its dysbiosis to neurodegenerative diseases, especially glaucoma.

Updated mechanisms of MASLD pathogenesis.

Metabolic dysfunction-associated steatotic liver disease (MASLD) has garnered considerable attention globally. Changing lifestyles, over-nutrition, and physical inactivity have promoted its development. MASLD is typically accompanied by obesity and is strongly linked to metabolic syndromes. Given that MASLD prevalence is on the rise, there is an urgent need to elucidate its pathogenesis. Hepatic lipid accumulation generally triggers lipotoxicity and induces MASLD or progress to metabolic dysfunction-associated steatohepatitis (MASH) by mediating endoplasmic reticulum stress, oxidative stress, organelle dysfunction, and ferroptosis. Recently, significant attention has been directed towards exploring the role of gut microbial dysbiosis in the development of MASLD, offering a novel therapeutic target for MASLD. Considering that there are no recognized pharmacological therapies due to the diversity of mechanisms involved in MASLD and the difficulty associated with undertaking clinical trials, potential targets in MASLD remain elusive. Thus, this article aimed to summarize and evaluate the prominent roles of lipotoxicity, ferroptosis, and gut microbes in the development of MASLD and the mechanisms underlying their effects. Furthermore, existing advances and challenges in the treatment of MASLD were outlined.

Vaginal dysbiosis - the association with reproductive outcomes in IVF patients: a systematic review and meta-analysis.

PURPOSE OF REVIEW: To examine impact of vaginal dysbiosis (VD), including bacterial vaginosis (BV) and aerobic vaginitis (AV) on reproductive outcomes of in vitro fertilization (IVF) patients. RECENT FINDINGS: BV-bacteria (e.g. Gardnerella ) and AV-bacteria (e.g. Streptococci and Enterococci ) have been identified in the endometrium. However, there is inconclusive evidence whether IVF patients with VD have lower success rates. SUMMARY: The present systematic review and meta-analysis of PubMed/Medline, until December 2023 included 25 studies, involving 6835 IVF patients. Overall VD was defined as an approximation of community state type IV, including BV and AV-type dysbiosis based on either molecular or microscopy methods. Outcomes were live birth rate (LBR), early pregnancy loss (EPL), clinical pregnancy rate (CPR), and biochemical pregnancy rate (BPR).Vaginal dysbiosis prevalence was 19% [1271/6835, 95% confidence interval (CI) 18-20%]. Six studies examined AV-type dysbiosis with a prevalence of 4% (26/628, 95% CI 3-6%). Vaginal dysbiosis correlates with a higher EPL [relative risk (RR) = 1.49, 95% CI 1.15-1.94] and lower CPR (RR = 0.82, 95% CI 0.70-0.95). No statistically significant impact of VD, BV, or AV was found on LBR and BPR.Thus, the association between VD and reproductive outcome remains puzzling as it is difficult to explain how VD impacts CPR and EPL but not LBR and BPR.

Prolonged Intake of Luvos Healing Earth does not alter the Composition of the Gut Microbiota in Patients with Diarrhea-predominant Irritable Bowel Syndrome and Healthy Controls.

BACKGROUND AND AIMS: The mineral compound Luvos Healing Earth (LHE) is a commercially available remedy empirically used for a variety of gastrointestinal disorders. The aim of this study was to investigate the possible effect of prolonged LHE therapy on gut microbiota in healthy individuals and in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). METHODS: In this prospective exploratory study, a total of 20 participants, including 12 healthy controls and 8 patients with IBS-D, received treatment with LHE (Magenfein Granulat, 1 sachet bid) for 6 weeks. Fecal samples were collected for microbiota analysis in the morning fasting state at regular intervals at 6 different timepoints: 2 weeks before starting therapy (Screen), and every 2 weeks during LHE therapy (V0-V3). Additionally, a follow-up visit was scheduled 4 weeks after the end of treatment (V4). Microbiota analysis was performed using the GA-map® Dysbiosis Test Lx v2. Dysbiosis Index, bacterial diversity, as well as the balance or imbalance of functionally important bacteria were assessed. RESULTS: The microbiota analysis revealed an overlap in gut microbiota profiles between healthy controls and patients with IBS-D. Bacterial communities were consistently stable during the entire treatment period, and no significant variations in composition were observed 4 weeks after the end of the therapeutic intervention. There was a remarkable stability of microbiota profiles over time within each individual and a high inter-individual variation. The majority of fecal samples exhibited profiles, reflecting an eubiotic state, with no significant changes in dysbiosis index, functional bacteria profiles, or bacterial diversity. CONCLUSION: Our findings indicate intraindividual resilience of microbiota consortia during the entire study period. Prolonged intake of LHE does not cause significant alterations in fecal microbiota profiles in healthy controls and patients with IBS-D. Luvos Healing Earth does not affect the stability of gut microbial diversity and bacterial functions.

Gut Microbiome-Related Anti-Inflammatory Effects of Aryl Hydrocarbon Receptor Activation on Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is one of the most prevalent chronic inflammations of the gastrointestinal tract (GIT). The gut microbial population, the cytokine milieu, the aryl hydrocarbon receptor (AHR) expressed by immune and nonimmune cells and the intrinsic pathway of Th-cell differentiation are implicated in the immunopathology of IBD. AHR activation requires a delicate balance between regulatory and effector T-cells; loss of this balance can cause local gut microbial dysbiosis and intestinal inflammation. Thus, the study of the gut microbiome in association with AHR provides critical insights into IBD pathogenesis and interventions. This review will focus on the recent advancements to form conceptional frameworks on the benefits of AHR activation by commensal gut bacteria in IBD.

Gut microbial dysbiosis in the pathogenesis of leukemia: an immune-based perspective.

Leukemias are a set of clonal hematopoietic malignant diseases that develop in the bone marrow. Several factors influence leukemia development and progression. Among these, the gut microbiota is a major factor influencing a wide array of its processes. The gut microbial composition is linked to the risk of tumor development and the host's ability to respond to treatment, mostly due to the immune-modulatory effects of their metabolites. Despite such strong evidence, its role in the development of hematologic malignancies still requires attention of investigators worldwide. In this review, we make an effort to discuss the role of host gut microbiota-immune crosstalk in leukemia development and progression. Additionally, we highlight certain recently developed strategies to modify the gut microbial composition that may help to overcome dysbiosis in leukemia patients in the near future.

Potential effects of nutrition-induced alteration of gut microbiota on inflammatory bowel disease: A review.

Inflammatory bowel disease (IBD), mainly comprising ulcerative colitis and Crohn's disease, is a group of gradually progressive diseases bringing significant mental anguish and imposes serious economic burdens. Interplay of genetic, environmental, and immunological factors have been implicated in its pathogenesis. Nutrients, as crucial environmental determinants, mainly encompassing carbohydrates, fats, proteins, and micronutrients, are closely related to the pathogenesis and development of IBD. Nutrition is essential for maintaining the dynamic balance of intestinal eco-environments to ensure intestinal barrier and immune homeostasis, while this balance can be disrupted easily by maladjusted nutrition. Research has firmly established that nutrition has the potential to shape the composition and function of gut microbiota to affect the disease course. Unhealthy diet and eating disorders lead to gut microbiota dysbiosis and further destroy the function of intestinal barrier such as the disruption of membrane integrity and increased permeability, thereby triggering intestinal inflammation. Notably, appropriate nutritional interventions, such as the Mediterranean diet, can positively modulate intestinal microecology, which may provide a promising strategy for future IBD prevention. In this review, we provide insights into the interplay between nutrition and gut microbiota and its effects on IBD and present some previously overlooked lines of evidence regarding the role of derived metabolites in IBD processes, such as trimethylamine N-oxide and imidazole propionate. Furthermore, we provide some insights into reducing the risk of onset and exacerbation of IBD by modifying nutrition and discuss several outstanding challenges and opportunities for future study.

Impact of Helicobacter pylori and metabolic syndrome on mast cell activation-related pathophysiology and neurodegeneration.

Both Helicobacter pylori (H. pylori) infection and metabolic syndrome (MetS) are highly prevalent worldwide. The emergence of relevant research suggesting a pathogenic linkage between H. pylori infection and MetS-related cardio-cerebrovascular diseases and neurodegenerative disorders, particularly through mechanisms involving brain pericyte deficiency, hyperhomocysteinemia, hyperfibrinogenemia, elevated lipoprotein-a, galectin-3 overexpression, atrial fibrillation, and gut dysbiosis, has raised stimulating questions regarding their pathophysiology and its translational implications for clinicians. An additional stimulating aspect refers to H. pylori and MetS-related activation of innate immune cells, mast cells (MC), which is an important, often early, event in systemic inflammatory pathologies and related brain disorders. Synoptically, MC degranulation may play a role in the pathogenesis of H. pylori and MetS-related obesity, adipokine effects, dyslipidemia, diabetes mellitus, insulin resistance, arterial hypertension, vascular dysfunction and arterial stiffness, an early indicator of atherosclerosis associated with cardio-cerebrovascular and neurodegenerative disorders. Meningeal MC can be activated by triggers including stress and toxins resulting in vascular changes and neurodegeneration. Likewise, H.pylori and MetS-related MC activation is linked with: (a) vasculitis and thromboembolic events that increase the risk of cardio-cerebrovascular and neurodegenerative disorders, and (b) gut dysbiosis-associated neurodegeneration, whereas modulation of gut microbiota and MC activation may promote neuroprotection. This narrative review investigates the intricate relationship between H. pylori infection, MetS, MC activation, and their collective impact on pathophysiological processes linked to neurodegeneration. Through a comprehensive search of current literature, we elucidate the mechanisms through which H. pylori and MetS contribute to MC activation, subsequently triggering cascades of inflammatory responses. This highlights the role of MC as key mediators in the pathogenesis of cardio-cerebrovascular and neurodegenerative disorders, emphasizing their involvement in neuroinflammation, vascular dysfunction and, ultimately, neuronal damage. Although further research is warranted, we provide a novel perspective on the pathophysiology and management of brain disorders by exploring potential therapeutic strategies targeting H. pylori eradication, MetS management, and modulation of MC to mitigate neurodegeneration risk while promoting neuroprotection.

Rheumatoid arthritis and the intestinal microbiome: probiotics as a potential therapy.

Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by swollen joints, discomfort, stiffness, osteoporosis, and reduced functionality. Genetics, smoking, dust inhalation, high BMI, and hormonal and gut microbiota dysbiosis are all likely causes of the onset or development of RA, but the underlying mechanism remains unknown. Compared to healthy controls, patients with RA have a significantly different composition of gut microbiota. It is well known that the human gut microbiota plays a key role in the initiation, maintenance, and operation of the host immune system. Gut microbiota dysbiosis has local or systematic adverse effects on the host immune system, resulting in host susceptibility to various diseases, including RA. Studies on the intestinal microbiota modulation and immunomodulatory properties of probiotics have been reported, in order to identify their potential possibility in prevention and disease activity control of RA. This review summarized current studies on the role and potential mechanisms of gut microbiota in the development and progression of RA, as well as the preventative and therapeutic effects and potential mechanisms of probiotics on RA. Additionally, we proposed the challenges and difficulties in the application of probiotics in RA, providing the direction for the research and application of probiotics in the prevention of RA.

Role of polyphenols in remodeling the host gut microbiota in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a common reproductive and metabolic condition in women of childbearing age and a major cause of anovulatory infertility. The pathophysiology of PCOS is complex. Recent studies have reported that apart from hyperandrogenism, insulin resistance, systemic chronic inflammation, and ovarian dysfunction, gut microbiota dysbiosis is also involved in PCOS development and may aggravate inflammation and metabolic dysfunction, forming a vicious cycle. As naturally occurring plant secondary metabolites, polyphenols have been demonstrated to have anticancer, antibacterial, vasodilator, and analgesic properties, mechanistically creating putative bioactive, low-molecular-weight metabolites in the human gut. Here, we summarize the role of gut microbiota dysbiosis in the development of PCOS and demonstrate the ability of different polyphenols - including anthocyanin, catechins, and resveratrol - to regulate gut microbes and alleviate chronic inflammation, thus providing new insights that may assist in the development of novel therapeutic strategies to treat women with PCOS.

Alteration in gut microbiota is associated with immune imbalance in Graves' disease.

Background: Graves' disease (GD), characterized by immune aberration, is associated with gut dysbiosis. Despite the growing interest, substantial evidence detailing the precise impact of gut microbiota on GD's autoimmune processes remains exceedingly rare. Objective: This study was designed to investigate the influence of gut microbiota on immune dysregulation in GD. Methods: It encompassed 52 GD patients and 45 healthy controls (HCs), employing flow cytometry and enzyme-linked immunosorbent assay to examine lymphocyte and cytokine profiles, alongside lipopolysaccharide (LPS) levels. Gut microbiota profiles and metabolic features were assessed using 16S rRNA gene sequencing and targeted metabolomics. Results: Our observations revealed a disturbed B-cell distribution and elevated LPS and pro-inflammatory cytokines in GD patients compared to HCs. Significant differences in gut microbiota composition and a marked deficit in short-chain fatty acid (SCFA)-producing bacteria, including ASV263(Bacteroides), ASV1451(Dialister), and ASV503(Coprococcus), were observed in GD patients. These specific bacteria and SCFAs showed correlations with thyroid autoantibodies, B-cell subsets, and cytokine levels. In vitro studies further showed that LPS notably caused B-cell subsets imbalance, reducing conventional memory B cells while increasing naïve B cells. Additionally, acetate combined with propionate and butyrate showcased immunoregulatory functions, diminishing cytokine production in LPS-stimulated cells. Conclusion: Overall, our results highlight the role of gut dysbiosis in contributing to immune dysregulation in GD by affecting lymphocyte status and cytokine production.

Polyphenols Influence the Development of Endometrial Cancer by Modulating the Gut Microbiota.

Dysbiosis of the microbiota in the gastrointestinal tract can induce the development of gynaecological tumours, particularly in postmenopausal women, by causing DNA damage and alterations in metabolite metabolism. Dysbiosis also complicates cancer treatment by influencing the body's immune response and disrupting the sensitivity to chemotherapy drugs. Therefore, it is crucial to maintain homeostasis in the gut microbiota through the effective use of food components that affect its structure. Recent studies have shown that polyphenols, which are likely to be the most important secondary metabolites produced by plants, exhibit prebiotic properties. They affect the structure of the gut microbiota and the synthesis of metabolites. In this review, we summarise the current state of knowledge, focusing on the impact of polyphenols on the development of gynaecological tumours, particularly endometrial cancer, and emphasising that polyphenol consumption leads to beneficial modifications in the structure of the gut microbiota.

The gut microbiota contributes to the infection of bovine viral diarrhea virus in mice.

Bovine viral diarrhea virus (BVDV) is prevalent worldwide and causes significant economic losses. Gut microbiota is a large microbial community and has a variety of biological functions. However, whether there is a correlation between gut microbiota and BVDV infection and what kind of relation between them have not been reported. Here, we found that gut microbiota composition changed in normal mice after infecting with BVDV, but mainly the low abundance microbe was affected. Interestingly, BVDV infection significantly reduced the diversity of gut microbiota and changed its composition in gut microbiota-dysbiosis mice. Furthermore, compared with normal mice of BVDV infection, there were more viral loads in the duodenum, jejunum, spleen, and liver of the gut microbiota-dysbiosis mice. However, feces microbiota transplantation (FMT) reversed these effects. The data above indicated that the dysbiosis of gut microbiota was a key factor in the high infection rate of BVDV. It is found that the IFN-I signal was involved by investigating the underlying mechanisms. The inhibition of the proliferation and increase in the apoptosis of peripheral blood lymphocytes (PBL) were also observed. However, FMT treatment reversed these changes by regulating PI3K/Akt, ERK, and Caspase-9/Caspase-3 pathways. Furthermore, the involvement of butyrate in the pathogenesis of BVDV was also further confirmed. Our results showed for the first time that gut microbiota acts as a key endogenous defense mechanism against BVDV infection; moreover, targeting regulation of gut microbiota structure and abundance may serve as a new strategy to prevent and control the disease.IMPORTANCEWhether the high infection rate of BVDV is related to gut microbiota has not been reported. In addition, most studies on BVDV focus on in vitro experiments, which limits the study of its prevention and control strategy and its pathogenic mechanism. In this study, we successfully confirmed the causal relationship between gut microbiota and BVDV infection as well as the potential molecular mechanism based on a mouse model of BVDV infection and a mouse model of gut microbiota dysbiosis. Meanwhile, a mouse model which is more susceptible to BVDV provided in this study lays an important foundation for further research on prevention and control strategy of BVDV and its pathogenesis. In addition, the antiviral effect of butyrate, the metabolites of butyrate-producing bacteria, has been further revealed. Overall, our findings provide a promising prevention and control strategy to treat this infectious disease which is distributed worldwide.

Impact of bread diet on intestinal dysbiosis and irritable bowel syndrome symptoms in quiescent ulcerative colitis: A pilot study.

Gut microbiota may be involved in the presence of irritable bowel syndrome (IBS)-like symptomatology in ulcerative colitis (UC) patients in remission. Bread is an important source of dietary fiber, and a potential prebiotic. To assess the effect of a bread baked using traditional elaboration, in comparison with using modern elaboration procedures, in changing the gut microbiota and relieving IBS-like symptoms in patients with quiescent ulcerative colitis. Thirty-one UC patients in remission with IBS-like symptoms were randomly assigned to a dietary intervention with 200 g/d of either treatment or control bread for 8 weeks. Clinical symptomatology was tested using questionnaires and inflammatory parameters. Changes in fecal microbiota composition were assessed by high-throughput sequencing of the 16S rRNA gene. A decrease in IBS-like symptomatology was observed after both the treatment and control bread interventions as reductions in IBS-Symptom Severity Score values (p-value < 0.001) and presence of abdominal pain (p-value < 0.001). The treatment bread suggestively reduced the Firmicutes/Bacteroidetes ratio (p-value = 0.058). In addition, the Firmicutes/Bacteroidetes ratio seemed to be associated with improving IBS-like symptoms as suggested by a slight decrease in patient without abdominal pain (p-value = 0.059). No statistically significant differential abundances were found at any taxonomic level. The intake of a bread baked using traditional elaboration decreased the Firmicutes/Bacteroidetes ratio, which seemed to be associated with improving IBS-like symptoms in quiescent ulcerative colitis patients. These findings suggest that the traditional bread elaboration has a potential prebiotic effect improving gut health (ClinicalTrials.gov ID number of study: NCT05656391).

Gut microbiota regulates hepatic ischemia-reperfusion injury-induced cognitive dysfunction via the HDAC2-ACSS2 axis in mice.

AIMS: Hepatic ischemia-reperfusion injury (HIRI) resulting from hepatic inflow occlusion, which is a common procedure in liver surgery is inevitable. Previous research has confirmed that the cognitive dysfunction induced by HIRI is closely related to dysbiosis of the gut microbiota. This research aims to investigate the mechanisms underlying this complication. METHODS: C57BL/6 mice underwent hepatic ischemia experimentally through the occlusion of the left hepatic artery and portal vein. To assess the HDAC2-ACSS2 axis, gut microbiota transplantation. Enzyme-linked immunosorbent assay and LC/MS short-chain fatty acid detection were utilized. RESULTS: The findings indicated a notable decline in ACSS2 expression in the hippocampus of mice experiencing hepatic ischemia-reperfusion injury, emphasizing the compromised acetate metabolism in this particular area. Furthermore, the cognitive impairment phenotype and the dysregulation of the HDAC2-ACSS2 axis could also be transmitted to germ-free mice via fecal microbial transplantation. Enzyme-linked immunosorbent assay revealed reduced Acetyl-coenzyme A (acetyl-CoA) and Acetylated lysine levels in the hippocampus. CONCLUSION: These findings suggest that acetate metabolism is impaired in the hippocampus of HIRI-induced cognitive impairment mice and related to dysbiosis, leading to compromised histone acetylation.

[Autoimmunity and oral cavity, where are we in 2023?] / Auto-immunité et cavité orale, où en est-on en 2023 ?

Autoimmune diseases (AIDs) remain an enigma to the current understanding of immune system functioning. Identifying their etiologies remains a major challenge, despite growing knowledge. The oral cavity has a very special place in regard to AIDs. The oral mucosa, the most exposed body's natural barrier to pathogens, plays a role in both education of the immune system and the organism's daily protection. On the one hand, systemic disturbance of the immune system can impact the oral sphere with early signs which are useful diagnostic tools. On the other hand, the current research efforts on interactions between microbiota and the immune system allow an update of the old hypothesis involving an initial infection to trigger autoimmunity. Dysbiosis of our microbiota, especially in the oral sphere, could lead to a breakdown in tolerance mechanisms. Immune tolerance has to maintain the integrity of the organism but also cohabitation with commensal microbiota. The relationship between periodontitis, a chronic infectious disease, and rheumatoid arthritis, one of the most common systemic autoimmune disorders, illustrates the possible relationship between chronic infections and the etiopathogenesis of autoimmunity. Indeed, its association with oral pathogens involved in periodontal damage raises questions about a possible infectious etiology of rheumatoid arthritis (RA) which would place the management of periodontitis not only as mandatory RA's support therapy but also as a prophylactic gesture to prevent autoimmunity.

Title: Auto-immunité et cavité orale, où en est-on en 2023 ? Abstract: Les maladies auto-immunes (MAI) restent une énigme dans notre compréhension du système immunitaire. L'identification de leurs étiologies demeure un défi majeur en dépit d'une augmentation exponentielle de nos connaissances sur le fonctionnement du système immunitaire. La cavité orale a une place particulière vis-à-vis des MAI. La muqueuse buccale présente les barrières naturelles de l'organisme parmi les plus exposées à des agents pathogènes. À ce titre, elles jouent un rôle dans l'éducation du système immunitaire, puis dans la protection quotidienne de l'organisme. Les perturbations du système immunitaire se manifestent fréquemment par des conséquences au niveau de la sphère buccale, le plus souvent précocement, permettant d'initier une démarche diagnostique. L'effort de recherche actuel sur les interactions entre microbiotes et système immunitaire permet de moderniser l'hypothèse historique liant une origine infectieuse à l'apparition de l'auto-immunité, en y apportant quelques nuances.

Integrated multi-omics analysis reveals gut microbiota dysbiosis and systemic disturbance in major depressive disorder.

Major depressive disorder (MDD) involves systemic changes in peripheral blood and gut microbiota, but the current understanding is incomplete. Herein, we conducted a multi-omics analysis of fecal and blood samples obtained from an observational cohort including MDD patients (n = 99) and healthy control (HC, n = 50). 16S rRNA sequencing of gut microbiota showed structural alterations in MDD, as characterized by increased Enterococcus. Metagenomics sequencing of gut microbiota showed substantial functional alterations including upregulation in the superpathway of the glyoxylate cycle and fatty acid degradation and downregulation in various metabolic pathways in MDD. Plasma metabolomics revealed decreased amino acids and bile acids, together with increased sphingolipids and cholesterol esters in MDD. Notably, metabolites involved in arginine and proline metabolism were decreased while sphingolipid metabolic pathway were increased. Mass cytometry analysis of blood immune cell subtypes showed rises in proinflammatory immune subsets and declines in anti-inflammatory immune subsets in MDD. Furthermore, our findings revealed disease severity-related factors of MDD. Interestingly, we classified MDD into two immune subtypes that were highly correlated with disease relapse. Moreover, we established discriminative signatures that differentiate MDD from HC. These findings contribute to a comprehensive understanding of the MDD pathogenesis and provide valuable resources for the discovery of biomarkers.

Unveiling the connection between gut microbiome and metabolic health in individuals with chronic spinal cord injury.

Accumulating evidence has revealed that alterations in the gut microbiome following spinal cord injury (SCI) exhibit similarities to those observed in metabolic syndrome. Considering the causal role of gut dysbiosis in metabolic syndrome development, SCI-induced gut dysbiosis may be a previously unidentified contributor to the increased risk of cardiometabolic diseases, which has garnered attention. With a cross-sectional design, we evaluated the correlation between gut microbiome composition and functional potential with indicators of metabolic health among 46 individuals with chronic SCI. Gut microbiome communities were profiled using next-generation sequencing techniques. Indices of metabolic health, including fasting lipid profile, glucose tolerance, insulin resistance, and inflammatory markers, were assessed through fasting blood tests and an oral glucose tolerance test. We used multivariate statistical techniques (i.e., regularized canonical correlation analysis) to identify correlations between gut bacterial communities, functional pathways, and metabolic health indicators. Our findings spotlight bacterial species and functional pathways associated with complex carbohydrate degradation and maintenance of gut barrier integrity as potential contributors to improved metabolic health. Conversely, those correlated with detrimental microbial metabolites and gut inflammatory pathways demonstrated associations with poorer metabolic health outcomes. This cross-sectional investigation represents a pivotal initial step toward comprehending the intricate interplay between the gut microbiome and metabolic health in SCI. Furthermore, our results identified potential targets for future research endeavors to elucidate the role of the gut microbiome in metabolic syndrome in this population.NEW & NOTEWORTHY Spinal cord injury (SCI) is accompanied by gut dysbiosis and the impact of this on the development of metabolic syndrome in this population remains to be investigated. Our study used next-generation sequencing and multivariate statistical analyses to explore the correlations between gut microbiome composition, function, and metabolic health indices in individuals with chronic SCI. Our results point to potential gut microbial species and functional pathways that may be implicated in the development of metabolic syndrome.