Diet, microbiota and autoimmune diseases

Huang-Lian-Jie-Du decoction ameliorates sepsis through dynamic regulation of immune response and gut microbiota-metabolite axis

Sepsis remains a life-threatening condition with high mortality rates despite current therapeutic approaches. While Huang-Lian-Jie-Du Decoction (HLJDD), a traditional Chinese medicine formula, has been historically used to treat inflammatory conditions, its therapeutic potential in sepsis and underlying mechanisms remain unexplored. This study investigated HLJDD's comprehensive effects on sepsis pathophysiology using a rat cecal ligation and puncture (CLP) model. HLJDD significantly improved survival rates and demonstrated sophisticated immunomodulatory effects through temporal regulation of the biphasic immune response characteristic of sepsis. In early sepsis, HLJDD suppressed pro-inflammatory cytokines (IL-1β, IL-6) while maintaining defensive inflammation. During late sepsis, it counteracted immunosuppression by reducing IL-10 levels and CD4+CD25+ T cell populations while protecting CD4+ and CD8+ T cells from apoptosis. Notably, HLJDD demonstrated dynamic regulation of the gut microbiota-metabolite axis. It enhanced beneficial bacterial populations (Firmicutes, Lactobacillus) while suppressing potentially pathogenic species (Bacteroides, Parabacteroides). Metabolomic analysis revealed time-dependent modulation of short-chain fatty acids, with elevated levels at 12 h followed by strategic reduction at 18-30 h, coordinating with changes in SCFA-producing bacteria. This temporal metabolic regulation corresponded with improved intestinal barrier function and balanced immune responses. The study unveils HLJDD's novel mechanism of action through synchronized modulation of immune responses, gut microbiota, and metabolite profiles, presenting a multi-target therapeutic approach that addresses the complex pathophysiology of sepsis. These findings provide a strong foundation for further clinical investigation of HLJDD as an innovative treatment strategy for sepsis.

Oral Microbiome Dysbiosis and Citrullination in Rheumatoid Arthritis

Rheumatoid arthritis and periodontal diseases, both characterized by chronic inflammation, share many common risk factors, sparking interest in understanding their established association. Emerging research has shed light on the link between these two diseases potentially occurring through the intricate interactions within the oral microbiome. The enrichment of pathogenic strains and species in this microbial community disrupts the delicate balance of both ecological and immunological homeostasis with the host. Particular attention has been paid to the role of key pathogens, such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, known for their immunomodulatory abilities. The generation of an autoimmune response against proteins modified by citrullination is known to be a key step in the pathogenesis of RA. Importantly, the bidirectional citrullination mediated by both host innate immune cells and oral bacteria generates citrullinated peptide neoepitopes, which may serve as potential triggers for the loss of tolerance and subsequent autoimmunity in susceptible individuals. This review highlights the importance of understanding the mechanisms through which oral microbiome dysbiosis and citrullination contribute to the onset and progression of RA. Insights into these mechanisms not only advance pathobiological understanding but also offer potential therapeutic targets. Furthermore, we discuss the potential impact of nonsurgical periodontal treatment in modifying disease progression or mitigating RA, underscoring the critical role of periodontal health in managing systemic inflammatory conditions.

The role of gut microbiota in different murine models of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by immune system dysfunction that can lead to serious health issues and mortality. Recent investigations highlight the role of gut microbiota alterations in modulating inflammation and disease severity in SLE. This review specifically summaries the variations in gut microbiota composition across various murine models of lupus. By focusing on these differences, we aim to elucidate the intricate relationship between gut microbiota dysbiosis and the development and progression of SLE in preclinical settings.

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

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

Understanding Autoimmunity: Mechanisms, Predisposing Factors, and Cytokine Therapies

Autoimmunity refers to an organism's immune response against its own healthy cells, tissues, or components, potentially leading to irreversible damage to vital organs. Central and peripheral tolerance mechanisms play crucial roles in preventing autoimmunity by eliminating self-reactive T and B cells. The disruption of immunological tolerance, characterized by the failure of these mechanisms, results in the aberrant activation of autoreactive lymphocytes that target self-tissues, culminating in the pathogenesis of autoimmune disorders. Genetic predispositions, environmental exposures, and immunoregulatory disturbances synergistically contribute to the susceptibility and initiation of autoimmune pathologies. Within the realm of immune therapies for autoimmune diseases, cytokine therapies have emerged as a specialized strategy, targeting cytokine-mediated regulatory pathways to rectify immunological imbalances. Proinflammatory cytokines are key players in inducing and propagating autoimmune inflammation, highlighting the potential of cytokine therapies in managing autoimmune conditions. This review discusses the etiology of autoimmune diseases, current therapeutic approaches, and prospects for future drug design.

Familial clustering of dysbiotic oral and fecal microbiomes in juvenile dermatomyositis

Juvenile dermatomyositis (JDM) is a rare immune-mediated disease of childhood with putative links to microbial exposures. In this multi-center, prospective, observational cohort study, we evaluated whether JDM is associated with discrete oral and gut microbiome signatures. We generated 16S rRNA sequencing data from fecal, saliva, supragingival, and subgingival plaque samples from JDM probands (n = 28). To control for genetic and environmental determinants of microbiome community structure, we also profiled microbiomes of unaffected family members (n = 27 siblings, n = 26 mothers, and n = 17 fathers). Sample type (oral-vs-fecal) and nuclear family unit were the predominant variables explaining variance in microbiome diversity, more so than having a diagnosis of JDM. The oral and gut microbiomes of JDM probands were more similar to their own unaffected siblings than they were to the microbiomes of other JDM probands. In a sibling-paired within-family analysis, several potentially immunomodulatory bacterial taxa were differentially abundant in the microbiomes of JDM probands compared to their unaffected siblings, including Faecalibacterium (gut) and Streptococcus (oral cavity). While microbiome features of JDM are often shared by unaffected family members, the loss or gain of specific fecal and oral bacteria may play a role in disease pathogenesis or be secondary to immune dysfunction in susceptible individuals.

Microbial dysbiosis in systemic lupus erythematosus: a scientometric study

Introduction

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. Mounting evidence suggests microbiota dysbiosis augment autoimmune response. This study aims to provide a systematic overview of this research field in SLE through a bibliometric analysis.

Methods

We conducted a comprehensive search and retrieval of literature related to microbial researches in SLE from the Web of Science Core Collection (WOSCC) database. The retrieved articles were subjected to bibliometric analysis using VOSviewer and Bibliometricx to explore annual publication output, collaborative patterns, research hotspots, current research status, and emerging trends.

Results

In this study, we conducted a comprehensive analysis of 218 research articles and 118 review articles. The quantity of publications rises annually, notably surging in 2015 and 2018. The United States and China emerged as the leading contributors in microbial research of SLE. Mashhad University of Medical Sciences had the highest publication outputs among the institutions. Frontiers in Immunology published the most papers. Luo XM and Margolles A were the most prolific and highly cited contributors among individual authors. Microbial research in SLE primarily focused on changes in microbial composition, particularly gut microbiota, as well as the mechanisms and practical applications in SLE. Recent trends emphasize "metabolites," "metabolomics," "fatty acids," "T cells," "lactobacillus," and "dietary supplementation," indicating a growing emphasis on microbial metabolism and interventions in SLE.

Conclusion

This study provides a thorough analysis of the research landscape concerning microbiota in SLE. The microbial research in SLE mainly focused on three aspects: microbial dysbiosis, mechanism studies and translational studies (microbiota-based therapeutics). It identifies current research trends and focal points, offering valuable guidance for scholars in the field.

Unraveling the intricate dance of the Mediterranean diet and gut microbiota in autoimmune resilience

The nutritional habits regulate the gut microbiota and increase risk of an autoimmune disease. Western diet is rich in sugars, meat, and poly-unsaturated fatty acids, which lead to dysbiosis of intestinal microbiota, disruption of gut epithelial barrier and chronic mucosal inflammation. In contrast, the Mediterranean Diet (MedDiet) is abundant in ω3 fatty acids, fruits, and vegetables, possessing anti-inflammatory properties that contribute to the restoration of gut eubiosis. Numerous studies have extensively examined the impact of MedDiet and its components on both health and various disease states. Additionally, specific investigations have explored the correlation between MedDiet, microbiota, and the risk of autoimmune diseases. Furthermore, the MedDiet has been linked to a reduced risk of cardiovascular diseases, playing a pivotal role in lowering mortality rates among individuals with autoimmune diseases and comorbidities. The aim of the present review is to specifically highlight current knowledge regarding possible interactions of MedDiet with the patterns of intestinal microbiota focusing on autoimmunity and a blueprint through dietary modulations for the prevention and management of disease's activity and progression.

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

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

Unravelling the Link between the Gut Microbiome and Autoimmune Kidney Diseases: A Potential New Therapeutic Approach

The gut microbiota and short chain fatty acids (SCFA) have been associated with immune regulation and autoimmune diseases. Autoimmune kidney diseases arise from a loss of tolerance to antigens, often with unclear triggers. In this review, we explore the role of the gut microbiome and how disease, diet, and therapy can alter the gut microbiota consortium. Perturbations in the gut microbiota may systemically induce the translocation of microbiota-derived inflammatory molecules such as liposaccharide (LPS) and other toxins by penetrating the gut epithelial barrier. Once in the blood stream, these pro-inflammatory mediators activate immune cells, which release pro-inflammatory molecules, many of which are antigens in autoimmune diseases. The ratio of gut bacteria Bacteroidetes/Firmicutes is associated with worse outcomes in multiple autoimmune kidney diseases including lupus nephritis, MPO-ANCA vasculitis, and Goodpasture's syndrome. Therapies that enhance SCFA-producing bacteria in the gut have powerful therapeutic potential. Dietary fiber is fermented by gut bacteria which in turn release SCFAs that protect the gut barrier, as well as modulating immune responses towards a tolerogenic anti-inflammatory state. Herein, we describe where the current field of research is and the strategies to harness the gut microbiome as potential therapy.

Dietary tryptophan and genetic susceptibility expand gut microbiota that promote systemic autoimmune activation

Tryptophan modulates disease activity and the composition of microbiota in the B6.Sle1.Sle2.Sle3 (TC) mouse model of lupus. To directly test the effect of tryptophan on the gut microbiome, we transplanted fecal samples from TC and B6 control mice into germ-free or antibiotic-treated non-autoimmune B6 mice that were fed with a high or low tryptophan diet. The recipient mice with TC microbiota and high tryptophan diet had higher levels of immune activation, autoantibody production and intestinal inflammation. A bloom of Ruminococcus gnavus (Rg), a bacterium associated with disease flares in lupus patients, only emerged in the recipients of TC microbiota fed with high tryptophan. Rg depletion in TC mice decreased autoantibody production and increased the frequency of regulatory T cells. Conversely, TC mice colonized with Rg showed higher autoimmune activation. Overall, these results suggest that the interplay of genetic and tryptophan can influence the pathogenesis of lupus through the gut microbiota.

Phenoptosis and the Various Types of Natural Selection

In the first description of evolution, the fundamental mechanism is the natural selection favoring the individuals best suited for survival and reproduction (selection at the individual level or classical Darwinian selection). However, this is a very reductive description of natural selection that does not consider or explain a long series of known phenomena, including those in which an individual sacrifices or jeopardizes his life on the basis of genetically determined mechanisms (i.e., phenoptosis). In fact, in addition to (i) selection at the individual level, it is essential to consider other types of natural selection such as those concerning: (ii) kin selection and some related forms of group selection; (iii) the interactions between the innumerable species that constitute a holobiont; (iv) the origin of the eukaryotic cell from prokaryotic organisms; (v) the origin of multicellular eukaryotic organisms from unicellular organisms; (vi) eusociality (e.g., in many species of ants, bees, termites); (vii) selection at the level of single genes, or groups of genes; (viii) the interactions between individuals (or more precisely their holobionts) of the innumerable species that make up an ecosystem. These forms of natural selection, which are all effects and not violations of the classical Darwinian selection, also show how concepts as life, species, individual, and phenoptosis are somewhat not entirely defined and somehow arbitrary. Furthermore, the idea of organisms selected on the basis of their survival and reproduction capabilities is intertwined with that of organisms also selected on the basis of their ability to cooperate and interact, even by losing their lives or their distinct identities.

Intermittent Fasting on Neurologic Diseases: Potential Role of Gut Microbiota

As the global population ages, the prevalence of neurodegenerative diseases is surging. These disorders have a multifaceted pathogenesis, entwined with genetic and environmental factors. Emerging research underscores the profound influence of diet on the development and progression of health conditions. Intermittent fasting (IF), a dietary pattern that is increasingly embraced and recommended, has demonstrated potential in improving neurophysiological functions and mitigating pathological injuries with few adverse effects. Although the precise mechanisms of IF's beneficial impact are not yet completely understood, gut microbiota and their metabolites are believed to be pivotal in mediating these effects. This review endeavors to thoroughly examine current studies on the shifts in gut microbiota and metabolite profiles prompted by IF, and their possible consequences for neural health. It also highlights the significance of dietary strategies as a clinical consideration for those with neurological conditions.

Autoimmunity in people with cystic fibrosis

Cystic fibrosis (CF) clinicians may see patients who have difficult-to-manage symptoms that do not have a clear CF-related etiology, such as unusual gastrointestinal (GI) complaints, vasculitis, or arthritis. Alterations in immunity, inflammation and intraluminal dysbiosis create a milieu that may lead to autoimmunity, and the CF transmembrane regulator protein may have a direct role as well. While autoantibodies and other autoimmune markers may develop, these may or may not lead to organ involvement, therefore they are helpful but not sufficient to establish an autoimmune diagnosis. Autoimmune involvement of the GI tract is the best-established association. Next steps to understand autoimmunity in CF should include a more in-depth assessment of the community perspective on its impact. In addition, bringing together specialists in various fields including, but not limited to, pulmonology, gastroenterology, immunology, and rheumatology, would lead to cross-dissemination and help define the path forward in basic science and clinical practice.

Analysis of microbiota profile and nutritional status in male professional football players

BACKGROUND

The interest in the effect of gut microbiota on athlete health has increased in recent years. Available data indicate a relationship between gut microbiota composition and physical activity, suggesting that changes in the microbiota may contribute to the host's physical performance. Studies show that leaky gut syndrome is highly correlated with upper respiratory infections and gastrointestinal disorders in endurance sports. This study aims to reveal the relationship between microbiota profiles, and the nutritional status of football players who perform endurance exercises.

METHODS

Twenty male professional football players playing in one of the Turkish Football Federation Second League clubs participated in the study. Fecal samples were collected and stored at -86 °C, and the fecal microbiota was analyzed through 16s rRNA gene sequencing. The body composition of the football players was measured using a bioelectrical impedance analyzer. In addition, the 3-day food intake of the participants was recorded with the help of a dietitian.

RESULTS

In the microbiota of football players, four phyla, 10 genera, and four species with densities above 1% were found. Body fat percentage was observed to be negatively correlated with the species of Faecalibacterium prausnitzii and Bacteroides vulgatus and the genus of Faecalibacterium (P<0.05). Considering the nutritional status, the fat intake was found to be positively correlated with Actinobacteria and Blautia coccoides; energy and fiber intake with Prevotella and Prevotella copri (P<0.05). In addition, there was a negative correlation between carbohydrate intake and Faecalibacterium (P<0.05).

CONCLUSIONS

Our study is the first to reveal the microbiota profile of professional Turkish football players. It was found that football players' nutritional status and anthropometric measurements of are significantly related to phylum, genus and species ranks in the microbiota. These results support the bidirectional interaction between microbiota and sports. The relationship between microbiota and sports health/performance is thought to be further clarified with future studies.

Increased Risk of Systemic Lupus Erythematosus in Patients with Chronic Urticaria: A Systematic Review and Meta-analysis

Introduction

The association between systemic lupus erythematosus (SLE) and chronic urticaria (CU) has been suggested in the literature although the amount of evidence is still relatively limited. We aimed to combine all available studies on this association using systematic review and meta-analysis technique.

Methods

Potentially eligible studies were identified from Medline and EMBASE from inception to February 2023 using search strategy that comprised of terms for "chronic urticaria" and "systemic lupus erythematosus". The eligible study must consist of one group of patients with CU and another group of comparators without CU and must compare the prevalence of SLE in each group and report effect size with 95% confidence intervals (95% CIs). We extracted such data from each study to calculate a pooled odds ratio using the generic inverse variance method with random-effect model. Funnel plot was used to evaluate publication bias. Newcastle-Ottawa Scale was used to appraise the methodological quality of the included studies.

Results

A total of 5,155 articles were identified. After two rounds of independent review by four investigators, five studies met the eligibility criteria and were included in the meta-analysis. The meta-analysis found an increased prevalence of SLE among patients with CU compared with individuals without CU with the pooled odds ratio of 5.03 (95% CI, 2.57-9.85, I2 of 93%).

Conclusion

This systematic review and meta-analysis found that patients with CU had a significantly increased risk of SLE compared to individuals without CU.

Incorporating the Molecular Mimicry of Environmental Antigens into the Causality of Autoimmune Hepatitis

Molecular mimicry between foreign and self-antigens has been implicated as a cause of autoimmune hepatitis in experimental models and cross-reacting antibodies in patients. This review describes the experimental and clinical evidence for molecular mimicry as a cause of autoimmune hepatitis, indicates the limitations and uncertainties of this premise, and encourages investigations that assess diverse environmental antigens as sources of disease-relevant molecular mimics. Pertinent articles were identified in PubMed using multiple search phrases. Several pathogens have linear or conformational epitopes that mimic the self-antigens of autoimmune hepatitis. The occurrence of an acute immune-mediated hepatitis after vaccination for severe acute respiratory syndrome (SARS)-associated coronavirus 2 (SARS-CoV-2) has suggested that vaccine-induced peptides may mimic disease-relevant tissue antigens. The intestinal microbiome is an under-evaluated source of gut-derived antigens that could also engage in molecular mimicry. Chaperone molecules may enhance the pathogenicity of molecular mimics, and they warrant investigation. Molecular mimics of immune dominant epitopes within cytochrome P450 IID6, the autoantigen most closely associated with autoimmune hepatitis, should be sought in diverse environmental antigens and assessed for pathogenicity. Avoidance strategies, dietary adjustments, vaccine improvement, and targeted manipulation of the intestinal microbiota may emerge as therapeutic possibilities. In conclusion, molecular mimicry may be a missing causality of autoimmune hepatitis. Molecular mimics of key immune dominant epitopes of disease-specific antigens must be sought in diverse environmental antigens. The ubiquity of molecular mimicry compels rigorous assessments of peptide mimics for immunogenicity and pathogenicity in experimental models. Molecular mimicry may complement epigenetic modifications as causative mechanisms of autoimmune hepatitis.

Gut microbiota in SLE: from animal models to clinical evidence and pharmacological perspectives

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease driven by complex interactions between genetics and environmental factors. SLE is characterised by breaking self-immune tolerance and autoantibody production that triggers inflammation and damage of multiple organs. Given the highly heterogeneous nature of SLE, the treatments currently used are still not satisfactory with considerable side effects, and the development of new therapies is a major health issue for better patient management. In this context, mouse models significantly contribute to our knowledge of the pathogenesis of SLE and are an invaluable tool for testing novel therapeutic targets. Here, we discuss the role of the most used SLE mouse models and their contribution to therapeutic improvement. Considering the complexity of developing targeted therapies for SLE, adjuvant therapies are also increasingly proposed. Indeed, murine and human studies have recently revealed that gut microbiota is a potential target and holds great promises for successful new SLE therapies. However, the mechanisms of gut microbiota dysbiosis in SLE remain unclear to date. In this review, we propose an inventory of existing studies investigating the relationship between gut microbiota dysbiosis and SLE to establish microbiome signature that may serve as a potential biomarker of the disease and its severity as well as a new potential therapy target. This approach may open new possibilities for early diagnosis, prevention and therapeutic perspectives of SLE based on gut microbiome.

PPARγ Gene as a Possible Link between Acquired and Congenital Lipodystrophy and its Modulation by Dietary Fatty Acids

Lipodystrophy syndromes are rare diseases that could be of genetic or acquired origin. The main complication of lipodystrophy is the dysfunction of adipose tissue, which leads to an ectopic accumulation of triglycerides in tissues such as the liver, pancreas and skeletal muscle. This abnormal fat distribution is associated with hypertriglyceridemia, insulin resistance, liver steatosis, cardiomyopathies and chronic inflammation. Although the origin of acquired lipodystrophies remains unclear, patients show alterations in genes related to genetic lipodystrophy, suggesting that this disease could be improved or aggravated by orchestrating gene activity, for example by diet. Nowadays, the main reason for adipose tissue dysfunction is an imbalance in metabolism, caused in other pathologies associated with adipose tissue dysfunction by high-fat diets. However, not all dietary fats have the same health implications. Therefore, this article aims to summarize the main genes involved in the pathophysiology of lipodystrophy, identify connections between them and provide a systematic review of studies published between January 2017 and January 2022 of the dietary fats that can modulate the development of lipodystrophy through transcriptional regulation or the regulation of protein expression in adipocytes.

Role of the gut microbiome in multiple sclerosis: From etiology to therapeutics

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS that affects around one million people in the United States. Predisposition or protection from this disease is linked with both genetic and environmental factors. In recent years, gut microbiome has emerged as an important environmental factor in the pathobiology of MS. The gut microbiome supports various physiologic functions, including the development and maintenance of the host immune system, the perturbation of which is known as dysbiosis and has been linked with multiple diseases including MS. We and others have shown that people with MS (PwMS) have gut dysbiosis that is characterized by specific gut bacteria being enriched or depleted. Consequently, there is an emphasis on determining the mechanism(s) through which gut bacteria and/or their metabolites alter the course of MS through their ability to provide protection, predispose individuals, or promote disease progression. Improving our understanding of these mechanisms will allow us to harness the enormous potential of the gut microbiome as a diagnostic and/or therapeutic agent. In this chapter, we will discuss current advances in microbiome research in the context of MS, including a review of specific bacteria that are currently linked with this disease, potential mechanisms of disease pathogenesis, and the utility of microbiome-based therapy for PwMS.

Microbiome Changes in Connective Tissue Diseases and Vasculitis: Focus on Metabolism and Inflammation

The microbial community acts as an active player in maintaining homeostasis and immune functions through a continuous and changeable cross-talk with the host immune system. Emerging evidence suggests that altered microbial composition, known as dysbiosis, might perturb the delicate balance between the microbiota and the immune system, triggering inflammation and potentially contributing to the pathogenesis and development of chronic inflammatory diseases. This review will summarize the current evidence about the microbiome-immunity cross-talk, especially focusing on the microbiota alterations described in patients with rheumatic diseases and on the recent findings concerning the interaction between microbiota, metabolic function, and the immune system.

Impact of Nutritional Profile on Gut Microbiota Diversity in Patients with Celiac Disease

The pathogenesis of celiac disease (CD) is significantly influenced by gut microbiota. Daily nutritional profile influences the diversity of gut microbiota. This study was aimed to compare the abundance of gut microbiota in CD patients compared to normal control (NC), and to investigate the impact of nutritional factors on their fecal microbiota diversity. In this study, a selected panel of intestinal bacteria was assessed in 31 confirmed CD patients adhering to gluten-free diet (GFD) for more than 6 months and in 20 NC subjects. Stool samples were collected from each participant, DNA was extracted, and absolute quantitative real-time PCR (qPCR) was carried out. The gut microbiota including Bacteroidetes, Bifidobacterium, Clostridium, Staphylococcus, Enterobacteiaceae, Firmicutes, and Lactobacillus were assessed. The quantities of fruits, vegetables, meat, liquids, sugar and gluten-free candy/bread consumption were evaluated using a questionnaire. The proportion of Bifidobacterium, Firmicutes, and Lactobacillus in CD cases was significantly lower than NC (P < 0.005). Significant correlation coefficients between Bifidobacterium and Lactobacillus (P < 0.001), and also Firmicutes and Lactobacillus (P < 0.001) were recorded. Moreover, a significant association between medium amount of meat and bean consumptions and low abundance of Lactobacillus and Firmicutes (P = 0.024 and P = 0.027, respectively), and also high amount of bean consumptions and low abundance of Lactobacillus (P = 0.027) in CD were observed. The results showed that meat and bean consumptions could reduce the beneficial bacteria including Firmicutes and Lactobacillus in CD patients. Therefore, changes in the gut microbiota abundance may contribute to dietary changes and unimproved CD symptoms.

Patients with ankylosing spondylitis have high risk of irritable bowel syndrome. A long-term nationwide population-based cohort study

OBJECTIVE

Ankylosing spondylitis (AS) is a chronic inflammatory disease, might carry a high risk of irritable bowel syndrome (IBS) due to abnormal gut microbiota or inflammatory reaction.

METHODS

We conducted a 14-year retrospective cohort study based on Taiwan's National Health Insurance Research Database (NHIRD). A total of 4007 patients with newly diagnosed AS (outpatient visits≧3 times, or hospitalization≧1 time) and 988,084 non-AS comparisons were enrolled during 2000-2012. To ensure baseline comparability, the propensity score was matched by age, gender, comorbidities, and other possible confounders. The outcome was the incidence of IBS, followed up to the end of 2013. Cox proportional hazard model calculated adjusted hazard ratio (aHR) and the cumulative incidence of both groups was analyzed by the Kaplan-Meier method.

RESULT

After propensity score matching, baseline demographic characteristics were comparable between AS patients and the comparison group. The crude HR for IBS in the AS group was significantly higher 2.41 (95%C.I. =1.84-3.16) than comparison group. After adjusting for possible confounders, adjusted HR was 2.50 (95%C.I.=1.91-3.29). The cumulative incidence of IBS in AS was significantly higher than non-AS comparisons during the 14-year follow-up (P<0.001).

CONCLUSION

This nationwide population-based cohort study showed that patients with AS have higher risks of IBS than those of the non-AS comparison group.

Alterations of host-gut microbiome interactions in multiple sclerosis

Background

Multiple sclerosis (MS) has a complex genetic, immune and metabolic pathophysiology. Recent studies implicated the gut microbiome in MS pathogenesis. However, interactions between the microbiome and host immune system, metabolism and diet have not been studied over time in this disorder.

Methods

We performed a six-month longitudinal multi-omics study of 49 participants (24 untreated relapse remitting MS patients and 25 age, sex, race matched healthy control individuals. Gut microbiome composition and function were characterized using 16S and metagenomic shotgun sequencing. Flow cytometry was used to characterize blood immune cell populations and cytokine profiles. Circulating metabolites were profiled by untargeted UPLC-MS. A four-day food diary was recorded to capture the habitual dietary pattern of study participants.

Findings

Together with changes in blood immune cells, metagenomic analysis identified a number of gut microbiota decreased in MS patients compared to healthy controls, and microbiota positively or negatively correlated with degree of disability in MS patients. MS patients demonstrated perturbations of their blood metabolome, such as linoleate metabolic pathway, fatty acid biosynthesis, chalcone, dihydrochalcone, 4-nitrocatechol and methionine. Global correlations between multi-omics demonstrated a disrupted immune-microbiome relationship and a positive blood metabolome-microbiome correlation in MS. Specific feature association analysis identified a potential correlation network linking meat servings with decreased gut microbe B. thetaiotaomicron, increased Th17 cell and greater abundance of meat-associated blood metabolites. The microbiome and metabolome profiles remained stable over six months in MS and control individuals.

Interpretation

Our study identified multi-system alterations in gut microbiota, immune and blood metabolome of MS patients at global and individual feature level. Multi-OMICS data integration deciphered a potential important biological network that links meat intakes with increased meat-associated blood metabolite, decreased polysaccharides digesting bacteria, and increased circulating proinflammatory marker.

Funding

This work was supported by the Washington University in St. Louis Institute of Clinical and Translational Sciences, funded, in part, by Grant Number # UL1 TR000448 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award (Zhou Y, Piccio, L, Lovett-Racke A and Tarr PI); R01 NS10263304 (Zhou Y, Piccio L); the Leon and Harriet Felman Fund for Human MS Research (Piccio L and Cross AH). Cantoni C. was supported by the National MS Society Career Transition Fellowship (TA-180531003) and by donations from Whitelaw Terry, Jr. / Valerie Terry Fund. Ghezzi L. was supported by the Italian Multiple Sclerosis Society research fellowship (FISM 2018/B/1) and the National Multiple Sclerosis Society Post-Doctoral Fellowship (FG-190734474). Anne Cross was supported by The Manny & Rosalyn Rosenthal-Dr. John L. Trotter MS Center Chair in Neuroimmunology of the Barnes-Jewish Hospital Foundation. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

The Role of the Microbiota in Graves' Disease and Graves' Orbitopathy

Graves' disease (GD) is a clinical syndrome with an enlarged and overactive thyroid gland, an accelerated heart rate, Graves' orbitopathy (GO), and pretibial myxedema (PTM). GO is the most common extrathyroidal complication of GD. GD/GO has a significant negative impact on the quality of life. GD is the most common systemic autoimmune disorder, mediated by autoantibodies to the thyroid-stimulating hormone receptor (TSHR). It is generally accepted that GD/GO results from complex interactions between genetic and environmental factors that lead to the loss of immune tolerance to thyroid antigens. However, the exact mechanism is still elusive. Systematic investigations into GD/GO animal models and clinical patients have provided important new insight into these disorders during the past 4 years. These studies suggested that gut microbiota may play an essential role in the pathogenesis of GD/GO. Antibiotic vancomycin can reduce disease severity, but fecal material transfer (FMT) from GD/GO patients exaggerates the disease in GD/GO mouse models. There are significant differences in microbiota composition between GD/GO patients and healthy controls. Lactobacillus, Prevotella, and Veillonella often increase in GD patients. The commonly used therapeutic agents for GD/GO can also affect the gut microbiota. Antigenic mimicry and the imbalance of T helper 17 cells (Th17)/regulatory T cells (Tregs) are the primary mechanisms proposed for dysbiosis in GD/GO. Interventions including antibiotics, probiotics, and diet modification that modulate the gut microbiota have been actively investigated in preclinical models and, to some extent, in clinical settings, such as probiotics (Bifidobacterium longum) and selenium supplements. Future studies will reveal molecular pathways linking gut and thyroid functions and how they impact orbital autoimmunity. Microbiota-targeting therapeutics will likely be an essential strategy in managing GD/GO in the coming years.

Helicobacter pylori and its association with autoimmune diseases: systemic lupus erythematosus, rheumatoid arthritis and Sjögren syndrome

Helicobacter pylori (H. pylori) is a gram-negative bacterium that adapts to the gastric mucosa and provokes symptoms associated with gastritis. Chronic H. pylori infection in patients with a genetic predisposition can trigger autoimmune diseases due to the immune interaction of cellular and humoral responses. Infections are a triggering factor for systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjögren syndrome (SS), although the association between H. pylori and these diseases is unclear. Therefore, we reviewed this interaction and its clinical importance.

Impact of Body Mass Index on the Age of Relapsing-Remitting Multiple Sclerosis Onset: A Retrospective Study

A BACKROUND: Multiple sclerosis (MS) is a complex chronic disease of the central nervous system (CNS). Body mass index (BMI), a component of metabolic syndrome (MetS), is considered among the risk factors for MS. However, its role in MS remains ambiguous. OBJECTIVE: To examine the impact of BMI on the age of onset in patients with relapsing-remitting MS (RRMS) in a Greek cohort. METHODS: Data from 821 Greek patients with RRMS were collected. The BMI values were considered as quartiles. Comparisons for the demographic characteristics between the quartiles were made by Pearson’s chi-square test for the categorical variables and by ANOVA for the continuous variables. An overall p-value was calculated corresponding to trend for association. In case of significant association, further post-hoc analysis was performed in order to identify differences in demographic characteristics between specific BMI quartiles groups. Linear regression analyses were used to assess the relationship between BMI and age at onset of MS. RESULTS: Comparisons of participant characteristics by quartiles of BMI revealed that participants with the highest BMI had an older age of disease onset. Results from linear regression analysis showed that with each increase of 1 BMI unit, the age of RRMS onset increases by 0.255 (95% CI 0.136 to 0.374) years, p < 0.001. CONCLUSIONS: Patients with higher BMI, as a parameter of MetS, exhibit increased age of RRMS onset. Our results may present an alternative personalized approach for diagnosis, prognosis, and/or prevention of RRMS.

Single and Combinative Impacts of Healthy Eating Behavior and Physical Activity on COVID-19-like Symptoms among Outpatients: A Multi-Hospital and Health Center Survey

BACKGROUND

Healthy eating and physical activity are effective non-pharmacological approaches to boost immune function and contain the pandemic. We aimed to explore the associations and interactions between physical activity and healthy eating behavior with COVID-19-like symptoms (Slike-CV19S).

METHODS

A cross-sectional study was conducted on 3947 outpatients, from 14 February to 2 March 2020, at nine health facilities in Vietnam. Data collection included sociodemographic characteristics, healthy eating behavior (using the healthy eating score (HES) questionnaire), physical activity (using the short form international physical activity questionnaire), and Slike-CV19S. The associations and interactions were tested using logistic regression models.

RESULTS

Frequent intake of fruits (OR = 0.84; p = 0.016), vegetables (OR = 0.72; p = 0.036), and fish (OR = 0.43; p < 0.001) were associated with a lower Slike-CV19S likelihood, as compared with infrequent intake. Patients with higher HES levels (OR = 0.84; p = 0.033 for medium HES; OR = 0.77; p = 0.006 for high HES) or being physically active (OR = 0.69; p < 0.001) had a lower Slike-CV19S likelihood, as compared to those with low HES or physical inactivity, respectively. Patients with medium HES who were physically active (OR = 0.69; p = 0.005), or with high HES and physically active (OR = 0.58; p < 0.001), had a lower Slike-CV19S likelihood, as compared to those with low HES and physical inactivity.

CONCLUSIONS

Healthy eating behavior and physical activity showed single and combinative impacts on protecting people from Slike-CV19S. Strategic approaches are encouraged to improve healthy behaviors, which may further contribute to containing the pandemic.

Breast and gut microbiome in health and cancer

The microbiota plays essential roles in health and disease, in both the intestine and the extra-intestine. Dysbiosis of the gut microbiota causes dysfunction in the intestine, which leads to inflammatory, immune, and infectious diseases. Dysbiosis is also associated with diseases beyond the intestine via microbial translocation or metabolisms. The in situ breast microbiome, which may be sourced from the gut through lactation and sexual contact, could be altered and cause breast diseases. In this review, we summarize the recent progress in understanding the interactions among the gut microbiome, breast microbiome, and breast diseases. We discuss the intestinal microbiota, microbial metabolites, and roles of microbiota in immune system. We emphasize the novel roles and mechanisms of the microbiome (both in situ and gastrointestinal sourced) and bacterial products in the development and progression of breast cancer. The intestinal microbial translocation suggests that the gut microbiome is translocated to the skin and subsequently to the breast tissue. The gut bacterial translocation is also due to the increased intestinal permeability. The breast and intestinal microbiota are important factors in maintaining healthy breasts. Micronutrition queuine (Q) is derived from a de novo synthesized metabolite in bacteria. All human cells use queuine and incorporate it into the wobble anticodon position of specific transfer RNAs. We have demonstrated that Q modification regulates genes critical in tight junctions and migration in human breast cancer cells and a breast tumor model. We further discuss the challenges and future perspectives that can move the field forward for prevention, diagnosis, and treatment of breast diseases.

Immune-mediated inflammatory diseases and nutrition: results from an online survey on patients' practices and perceptions

Background

The central role of microbiota and the contribution of diet in immune-mediated inflammatory diseases (IMID) are increasingly examined. However, patients’ perspectives on nutrition and its impact on their disease has not received a lot of attention. We aimed to directly collect information from patients with IMID about their dietary behaviors and their perceptions of the influence of nutrition on their disease.

Methods

Adult patients with rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, Crohn’s disease, ulcerative colitis or psoriasis registered in an online patient community were invited to participate in the study and complete an online self-administered questionnaire. We assessed patients’ dietary knowledge and choices by collecting information on the diet regimens they were following or recommended and their perceptions of the diet and its consequences on their disease.

Results

Fifty patients per target disease were included with a mean age of 48.1 years (95%CI 46.7–49.6). Other sociodemographic and clinical characteristics varied across the diseases. Since diagnosis, 44% of the patients changed their eating habits, mainly patients with inflammatory bowel disease with 69% of these making the change on their own initiative. Patients who did not change their diet habits reported not having received nutritional advice from their healthcare professionals (HCP) in 69% of the cases. The perceived impact of nutrition on their symptoms was mixed (overall 74% of the patients reported positive consequences and 60% negative ones) and varied across the diseases. Patients with psoriasis only experienced positive consequences from changing their diet, such as reduction of stress and improved mental health, while patients with Crohn’s disease reported more negative effects such as increased fatigue and disturbed sleep. Patients with rheumatic diseases and ulcerative colitis reported weight loss and better physical fitness, but also increased fatigue.

Conclusions

Even if differences exist across diseases, the importance of nutrition and its potential positive role in symptom management is acknowledged by the majority of the patients. However, there is a need and a demand from patients to receive more dietary advice. Developing therapeutic education tools on nutrition for people with IMID and involving patients’ organizations would provide useful information and encourage communication between HCP and patients.

Dysbiosis of Gut Microbiota in Patients With Acute Myocardial Infarction

Acute myocardial infarction (AMI) continues as the main cause of morbidity and mortality worldwide. Interestingly, emerging evidence highlights the role of gut microbiota in regulating the pathogenesis of coronary heart disease, but few studies have systematically assessed the alterations and influence of gut microbiota in AMI patients. As one approach to address this deficiency, in this study the composition of fecal microflora was determined from Chinese AMI patients and links between gut microflora and clinical features and functional pathways of AMI were assessed. Fecal samples from 30 AMI patients and 30 healthy controls were collected to identify the gut microbiota composition and the alterations using bacterial 16S rRNA gene sequencing. We found that gut microflora in AMI patients contained a lower abundance of the phylum Firmicutes and a slightly higher abundance of the phylum Bacteroidetes compared to the healthy controls. Chao1 (P = 0.0472) and PD-whole-tree (P = 0.0426) indices were significantly lower in the AMI versus control group. The AMI group was characterized by higher levels of the genera Megasphaera, Butyricimonas, Acidaminococcus, and Desulfovibrio, and lower levels of Tyzzerella 3, Dialister, [Eubacterium] ventriosum group, Pseudobutyrivibrio, and Lachnospiraceae ND3007 group as compared to that in the healthy controls (P < 0.05). The common metabolites of these genera are mostly short-chain fatty acids, which reveals that the gut flora is most likely to affect the occurrence and development of AMI through the short-chain fatty acid pathway. In addition, our results provide the first evidence revealing remarkable differences in fecal microflora among subgroups of AMI patients, including the STEMI vs. NSTEMI, IRA-LAD vs. IRA-Non-LAD and Multiple (≥2 coronary stenosis) vs. Single coronary stenosis groups. Several gut microflora were also correlated with clinically significant characteristics of AMI patients, including LVEDD, LVEF, serum TnI and NT-proBNP, Syntax score, counts of leukocytes, neutrophils and monocytes, and fasting serum glucose levels. Taken together, the data generated enables the prediction of several functional pathways as based on the fecal microfloral composition of AMI patients. Such information may enhance our comprehension of AMI pathogenesis.

A systematic review and meta-analysis of observational studies on the association between animal protein sources and risk of rheumatoid arthritis

OBJECTIVE

The aim of this study was to investigate the linear and nonlinear dose-response associations of animal-based dietary protein intake and risk of developing rheumatoid arthritis (RA).

METHODS

A systematic search of MEDLINE, Scopus and Embase was conducted up to October 2020. Observational studies that report risk estimates of RA for animal-based protein consumption were included. We calculated pooled relative risks (RRs) by using a random-effects model. Linear and non-linear dose-response analyses were performed to examine the dose-response relations between animal-based protein consumption and RA.

RESULTS

Seven cohort studies (n = 457,554) with 3545 incident cases and six case-control studies with 3994 cases and 5252 controls were identified. Highest compared with the lowest category of fish consumption was inversely associated with risk of RA (RR: 0.89; 95% CI, 0.80 to 0.99; I² = 0%, n = 10). Also, a 100 g/day increment in fish intake was associated with a 15% decreased risk of RA. Dose-response analysis showed a modest U-shaped association between fish consumption and incidence of RA, with the lowest risk at a fish intake of 20-30 g/day (P_{non-linearity} = 0.04). We found no significant association between consumption of red meat, poultry or dairy and the risk of RA.

CONCLUSION

The present study revealed a significant reverse association between fish consumption and risk of RA. While we observed no association between red meat, dairy or poultry consumption and risk of RA. Further well-designed prospective studies are needed to support our findings.

Ginsenoside Rk3 alleviates gut microbiota dysbiosis and colonic inflammation in antibiotic-treated mice

Ginsenoside Rk3 is a natural prebiotic found in ginseng, has excellent pharmacological efficacy, especially antitumor effects, and can greatly benefit human health. Here, we investigated the impact of Rk3 intake on modulation of the gut microbiota and their metabolites as well as its effect on low-grade inflammation in mice. C57BL/6JFandd mice were administered different doses of Rk3 for two weeks after establishment of an antibiotic-mediated gut microbiota disturbance model. Interestingly, Rk3 intake induced substantial changes in the gut microbiota composition, enriched the Bacteroides, Alloprevotella and Blautia genera, and effectively ameliorated gut microbiota dysbiosis, with significantly decreased Firmicutes/Bacteroidetes ratios. These changes were accompanied by beneficial alterations in gut microbiota diversity and improved short-chain fatty acid levels. In addition, we found that Rk3 intervention repaired intestinal barrier dysfunction by increasing the expression of tight junction proteins (ZO-1, Occludin and Claudin-1), reducing colonic inflammatory cytokine levels, and suppressing TNF-α, IL-1β, and IL-6 overproduction. In conclusion, Rk3 improves intestinal inflammation and induces potentially beneficial changes in the gut microbiota, and these findings help elucidate host-microbe interactions.

Bidirectional communication between mast cells and the gut-brain axis in neurodegenerative diseases: Avenues for therapeutic intervention

Although the global incidence of neurodegenerative diseases has been steadily increasing, especially in adults, there are no effective therapeutic interventions. Neurodegeneration is a heterogeneous group of disorders that is characterized by the activation of immune cells in the central nervous system (CNS) (e.g., mast cells and microglia) and subsequent neuroinflammation. Mast cells are found in the brain and the gastrointestinal tract and play a role in "tuning" neuroimmune responses. The complex bidirectional communication between mast cells and gut microbiota coordinates various dynamic neuro-cellular responses, which propagates neuronal impulses from the gastrointestinal tract into the CNS. Numerous inflammatory mediators from degranulated mast cells alter intestinal gut permeability and disrupt blood-brain barrier, which results in the promotion of neuroinflammatory processes leading to neurological disorders, thereby offsetting the balance in immune-surveillance. Emerging evidence supports the hypothesis that gut-microbiota exert a pivotal role in inflammatory signaling through the activation of immune and inflammatory cells. Communication between inflammatory cytokines and neurocircuits via the gut-brain axis (GBA) affects behavioral responses, activates mast cells and microglia that causes neuroinflammation, which is associated with neurological diseases. In this comprehensive review, we focus on what is currently known about mast cells and the gut-brain axis relationship, and how this relationship is connected to neurodegenerative diseases. We hope that further elucidating the bidirectional communication between mast cells and the GBA will not only stimulate future research on neurodegenerative diseases but will also identify new opportunities for therapeutic interventions.

Beneficial effect of Mediterranean diet on disease activity and cardiovascular risk in systemic lupus erythematosus patients: a cross-sectional study

OBJECTIVE

To analyse the influence of the Mediterranean diet (Med Diet) on SLE activity, damage accrual and cardiovascular disease risk markers.

METHODS

A cross-sectional study was conducted on 280 patients with SLE [46.9 (12.85) years]. Med Diet adherence was assessed through a 14-item questionnaire on food consumption frequency and habits (total score from 0 to 14 points; higher score is greater adherence to the Med Diet). CRP, homocysteine, SLEDAI-2K (SLE disease activity), and SLICC/ACR and SDI (damage accrual) were measured. Obesity, diabetes mellitus, hypertension and blood lipids, among others, were considered cardiovascular disease risk factors.

RESULTS

Greater adherence to the Med Diet was significantly associated with better anthropometric profiles, fewer cardiovascular disease risk factors, and lower disease activity and damage accrual scores (P ≤ 0.001 for SLEDAI and SDI). An inverse relationship between the Med Diet score and SLEDAI (P ≥ 0.001; β = -0.380), SDI (P ≤ 0.001; β = -0.740) and hsCRP (P = 0.039; β = -0.055) was observed. The odds ratio for having active SLE (SLEDAI ≥5) or the presence of damage (SDI ≥1) was lower among patients whose Med Diet score was higher (P ≤ 0.001). Finally, greater consumption of Med Diet foods (olive oil, fruits, vegetables, fish, etc.) and abstaining from red meat and meat products, sugars and pastries was associated with less SLE clinical activity and damage.

CONCLUSION

Greater adherence to the Med Diet seems to exert a beneficial effect on disease activity and cardiovascular risk in SLE patients. To confirm these findings, further longitudinal studies would be of interest.

Effects of PD-1/PD-L1 signaling pathway on intestinal flora in patients with colorectal cancer

OBJECTIVE

To explore the effects of the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) signaling pathway on the intestinal flora in patients with colorectal cancer (CRC).

METHODS

A total of 30 CRC patients treated with PD-1 monoclonal antibody therapy in the Oncology Department of our hospital from January 2018 to January 2019, and another 30 patients treated with routine non-immune therapy were enrolled. The feces specimens were collected for sequencing, the CRC model was established, and the 16S rRNA gene sequences in intestinal flora in feces specimens of mice were analyzed.

RESULTS

The 3-month progression-free survival could not be predicted through the gene count or abundance of metagenomic species (MGS) in intestinal microflora of patients. The gene count or MGS abundance was related to the clinical progression-free response. There were abundant unclassified Escherichia coli, s_lactobacillus and s_unclassified parasutterella in patients treated with PD-1. The reflection curve of microbiota had an obvious difference in richness (Chao1), but had no apparent difference in diversity (Shannon).

CONCLUSION

The PD-1/PD-L1 signaling pathway can regulate the metabolic activity of intestinal flora, thereby promoting immune surveillance of tumors.

The Emerging World of Microbiome in Autoimmune Disorders: Opportunities and Challenges

Trillions of commensal bacteria colonizing humans (microbiome) have emerged as essential player(s) in human health. The alteration of the same has been linked with diseases including autoimmune disorders such as multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis. Gut bacteria are separated from the host through a physical barrier such as skin or gut epithelial lining. However, the perturbation in the healthy bacterial community (gut dysbiosis) can compromise gut barrier integrity, resulting in translocation of bacterial contents across the epithelial barrier (leaky gut). Bacterial contents such as lipopolysaccharide and bacterial antigens can induce a systemic inflammatory environment through activation and induction of immune cells. The biggest question in the field is whether inflammation causes gut dysbiosis or dysbiosis leads to disease induction or propagation, i.e., it is inside out or outside in or both. In this review, we first discuss the microbiome profiling studies in various autoimmune disorders, followed by a discussion of potential mechanisms through which microbiome is involved in the pathobiology of diseases. A better understanding of the role of the microbiome in health and disease will help us harness the power of commensal bacteria for the development of novel therapeutic agents to treat autoimmune disorders.

The microbiome links between aging and lupus

BACKGROUND AND AIMS

Many forms of immune dysregulation, which lead to inflammaging and senescence, have been demonstrated in patients with systemic lupus erythematosus (SLE; lupus) and in the aging population. The discovery of the microbiome and its association with human health and pathology has led it to be the center of investigation as a major contributor to the pathogenesis of immunosenescence in both populations. Similar alterations to the microbiome in the form of dysbiosis, that are demonstrated in both aging and in lupus patients, may help explain the significant overlap in clinical manifestations seen in these groups.

METHODS

We performed an extensive literature review, utilizing the Pubmed search engine and Google Scholar for studies evaluating the microbiome in two groups, elderly populations and lupus patients (both murine and human models), between the years 2000-2019. We searched for the terms: microbiome, dysbiosis, lupus, elderly, aging and inflammaging, which yielded hundreds of articles, of which 114 were used for preparation of this paper. We compared the similarities between the populations.

RESULTS

We found that the similar processes of immune dysregulation, in both aging populations and lupus patients, extend to the microbiome, in the form of dysbiosis. Some of these similarities include loss of microbiota biodiversity, increased representation of microbes that are associated with inflammation and disease (i.e Proteobacteria, Bacteroidetes), a relative decrease in protective microbes with "anti-inflammatory" properties (i.e Firmicutes) and a subsequent compromise to the intestinal barrier, leading to leakage of proinflammatory microbial components in both groups.

CONCLUSIONS

We conclude that there are several similar alterations in the composition and function of the microbiome of lupus patients and aging individuals, leading to immunosenescence, which may also be a contributing mechanism in lupus. It seems in fact that the microbiome of SLE may actually be analogous to immunosenescence. This knowledge may help the continuous efforts in finding a solution for both conditions.

Microbiome-based interventions: therapeutic strategies in cancer immunotherapy

The composition of the commensal microbiota has recently emerged as a key element influencing the efficacy of cancer treatments. It has become apparent that the interplay between the microbiome and immune system within the host influences the response to immunotherapy, particularly immune checkpoint inhibitor therapy. Identifying the key components of the gut microbiota that influence this response is paramount for designing therapeutic interventions to enhance the response to cancer therapy. This review will discuss strategies being considered to modulate the gut microbiota, including fecal microbiota transplantation, administration of defined bacterial isolates as well as bacterial consortia, supplementation with probiotics, and lifestyle modifications such as dietary changes. Understanding the influence of the complex variables of the human microbiota on the effectiveness of cancer therapy will help drive the clinical design of microbial-based interventions in the field of oncology.

Diet and Nutrients in Gastrointestinal Chronic Diseases

Diet and nutrition are known to play key roles in many chronic gastrointestinal diseases, regarding both pathogenesis and therapeutic possibilities. A strong correlation between symptomatology, disease activity and eating habits has been observed in many common diseases, both organic and functional, such as inflammatory bowel disease and irritable bowel syndrome. New different dietary approaches have been evaluated in order improve patients’ symptoms, modulating the type of sugars ingested, the daily amount of fats or the kind of metabolites produced in gut. Even if many clinical studies have been conducted to fully understand the impact of nutrition on the progression of disease, more studies are needed to test the most promising approaches for different diseases, in order to define useful guidelines for patients.

Consumption of a Western-Style Diet Modulates the Response of the Murine Gut Microbiome to Ciprofloxacin

Dietary composition and antibiotic use have major impacts on the structure and function of the gut microbiome, often resulting in dysbiosis. Despite this, little research has been done to explore the role of host diet as a determinant of antibiotic-induced microbiome disruption. Here, we utilize a multi-omic approach to characterize the impact of Western-style diet consumption on ciprofloxacin-induced changes to gut microbiome structure and transcriptional activity. We found that Western diet consumption dramatically increased Bacteroides abundances and shifted the community toward the metabolism of simple sugars and mucus glycoproteins. Mice consuming a Western-style diet experienced a greater expansion of Firmicutes following ciprofloxacin treatment than those eating a control diet. Transcriptionally, we found that ciprofloxacin reduced the abundance of tricarboxylic acid (TCA) cycle transcripts on both diets, suggesting that carbon metabolism plays a key role in the response of the gut microbiome to this antibiotic. Despite this, we observed extensive diet-dependent differences in the impact of ciprofloxacin on microbiota function. In particular, at the whole-community level we detected an increase in starch degradation, glycolysis, and pyruvate fermentation following antibiotic treatment in mice on the Western diet, which we did not observe in mice on the control diet. Similarly, we observed diet-specific changes in the transcriptional activity of two important commensal bacteria, Akkermansia muciniphila and Bacteroides thetaiotaomicron, involving diverse cellular processes such as nutrient acquisition, stress responses, and capsular polysaccharide (CPS) biosynthesis. These findings demonstrate that host diet plays a role in determining the impacts of ciprofloxacin on microbiome composition and microbiome function.IMPORTANCE Due to the growing incidence of disorders related to antibiotic-induced dysbiosis, it is essential to determine how our "Western"-style diet impacts the response of the microbiome to antibiotics. While diet and antibiotics have profound impacts on gut microbiome composition, little work has been done to examine their combined effects. Previous work has shown that nutrient availability, influenced by diet, plays an important role in determining the extent of antibiotic-induced disruption to the gut microbiome. Thus, we hypothesize that the Western diet will shift microbiota metabolism toward simple sugar and mucus degradation and away from polysaccharide utilization. Because of bacterial metabolism's critical role in antibiotic susceptibility, this change in baseline metabolism will impact how the structure and function of the microbiome are impacted by ciprofloxacin exposure. Understanding how diet modulates antibiotic-induced microbiome disruption will allow for the development of dietary interventions that can alleviate many of the microbiome-dependent complications of antibiotic treatment.