Increased Ileal Immunoglobulin A Production and Immunoglobulin A-Coated Bacteria in Diarrhea-Predominant Irritable Bowel Syndrome

Exploring the diagnostic potential of immunoglobulin A-microbiota interplay in liver cirrhosis and spontaneous bacterial peritonitis

The human gut microbiota significantly impacts health, including liver conditions like liver cirrhosis (LC) and spontaneous bacterial peritonitis (SBP). Immunoglobulin A (IgA) plays a central role in maintaining gut microbial balance. Understanding IgA's interplay with gut microbiota and liver health is crucial. This study explores the relationship between fecal IgA levels, gut microbiota, and liver injury severity. A total of 69 LC patients and 30 healthy controls were studied. Fecal IgA levels were measured using ELISA, and IgA-coated bacteria were quantified via flow cytometry. Microbiota diversity and composition were assessed through 16S rRNA sequencing. Liver injury severity was graded using the Child-Pugh score. Statistical analyses determined correlations. LC patients had higher fecal IgA levels than controls, correlating positively with liver injury severity. Microbiota diversity decreased with severity, accompanied by shifts in composition favoring pro-inflammatory species. Ralstonia abundance positively correlated with liver injury, whereas Faecalibacterium showed a negative correlation. Specific microbial markers for SBP were identified. Functional profiling revealed altered microbial functionalities in LC and SBP. Elevated fecal IgA levels, coupled with microbiota alterations, correlate with liver injury severity in LC patients. Modulating gut microbiota could be a promising strategy for managing liver-related conditions. Further research is needed to understand underlying mechanisms and translate findings into clinical practice, potentially improving patient outcomes.

Distinct characteristics of the gut virome in patients with osteoarthritis and gouty arthritis

BACKGROUND/PURPOSE(S)

The gut microbiota and its metabolites play crucial roles in pathogenesis of arthritis, highlighting gut microbiota as a promising avenue for modulating autoimmunity. However, the characterization of the gut virome in arthritis patients, including osteoarthritis (OA) and gouty arthritis (GA), requires further investigation.

METHODS

We employed virus-like particle (VLP)-based metagenomic sequencing to analyze gut viral community in 20 OA patients, 26 GA patients, and 31 healthy controls, encompassing a total of 77 fecal samples.

RESULTS

Our analysis generated 6819 vOTUs, with a considerable proportion of viral genomes differing from existing catalogs. The gut virome in OA and GA patients differed significantly from healthy controls, showing variations in diversity and viral family abundances. We identified 157 OA-associated and 94 GA-associated vOTUs, achieving high accuracy in patient-control discrimination with random forest models. OA-associated viruses were predicted to infect pro-inflammatory bacteria or bacteria associated with immunoglobulin A production, while GA-associated viruses were linked to Bacteroidaceae or Lachnospiraceae phages. Furthermore, several viral functional orthologs displayed significant differences in frequency between OA-enriched and GA-enriched vOTUs, suggesting potential functional roles of these viruses. Additionally, we trained classification models based on gut viral signatures to effectively discriminate OA or GA patients from healthy controls, yielding AUC values up to 0.97, indicating the clinical utility of the gut virome in diagnosing OA or GA.

CONCLUSION

Our study highlights distinctive alterations in viral diversity and taxonomy within gut virome of OA and GA patients, offering insights into arthritis etiology and potential treatment and prevention strategies.

Single cell sequencing data identify distinct B cell and fibroblast populations in stricturing Crohn's disease

Single cell RNA sequencing of human full thickness Crohn's disease (CD) small bowel resection specimens was used to identify potential therapeutic targets for stricturing (S) CD. Using an unbiased approach, 16 cell lineages were assigned within 14,539 sequenced cells from patient-matched SCD and non-stricturing (NSCD) preparations. SCD and NSCD contained identical cell types. Amongst immune cells, B cells and plasma cells were selectively increased in SCD samples. B cell subsets suggested formation of tertiary lymphoid tissue in SCD and compared with NSCD there was an increase in IgG, and a decrease in IgA plasma cells, consistent with their potential role in CD fibrosis. Two Lumican-positive fibroblast subtypes were identified and subclassified based on expression of selectively enriched genes as fibroblast clusters (C) 12 and C9. Cells within these clusters expressed the profibrotic genes Decorin (C12) and JUN (C9). C9 cells expressed ACTA2; ECM genes COL4A1, COL4A2, COL15A1, COL6A3, COL18A1 and ADAMDEC1; LAMB1 and GREM1. GO and KEGG Biological terms showed extracellular matrix and stricture organization associated with C12 and C9, and regulation of WNT pathway genes with C9. Trajectory and differential gene analysis of C12 and C9 identified four sub-clusters. Intra sub-cluster gene analysis detected 13 co-regulated gene modules that aligned along predicted pseudotime trajectories. CXCL14 and ADAMDEC1 were key markers in module 1. Our findings support further investigation of fibroblast heterogeneity and interactions with local and circulating immune cells at earlier time points in fibrosis progression. Breaking these interactions by targeting one or other population may improve therapeutic management for SCD.

IgA coating of vaginal bacteria is reduced in the setting of bacterial vaginosis (BV) and preferentially targets BV-associated species

Immunoglobulin (Ig) bacterial coating has been described in the gastrointestinal tract and linked to inflammatory bowel disease; however, little is known about Ig coating of vaginal bacteria and whether it plays a role in vaginal health including bacterial vaginosis (BV). We examined Ig coating in 18 women with symptomatic BV followed longitudinally before, 1 week, and 1 month after oral metronidazole treatment. Immunoglobulin A (IgA) and/or immunoglobulin G (IgG) coating of vaginal bacteria was assessed by flow cytometry, and Ig coated and uncoated bacteria were sorted and characterized using 16S rRNA sequencing. Despite higher levels of IgG compared to IgA in cervicovaginal fluid, the predominant Ig coating the bacteria was IgA. The majority of bacteria were uncoated at all visits, but IgA coating significantly increased after treatment for BV. Despite similar amounts of uncoated and IgA coated majority taxa ( >1% total) across all visits, there was preferential IgA coating of minority taxa (0.2%-1% total) associated with BV including Sneathia, several Prevotella species, and others. At the time of BV, we identified a principal component (PC) driven by proinflammatory mediators that correlated positively with an uncoated BV-associated bacterial community and negatively with an IgA coated protective Lactobacillus bacterial community. The preferential coating of BV-associated species, increase in coating following metronidazole treatment, and positive correlation between uncoated BV-associated species and inflammation suggest that coating may represent a host mechanism designed to limit bacterial diversity and reduce inflammatory responses. Elucidating the role of Ig coating in vaginal mucosal immunity may promote new strategies to prevent recurrent BV.

Baizhu shaoyao decoction restores the intestinal barrier and brain-gut axis balance to alleviate diarrhea-predominant irritable bowel syndrome via FoxO1/FoxO3a

BACKGROUND

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common functional gastrointestinal disease. Besides, baizhu shaoyao decoction (BSD) is an effective treatment for IBS-D; however, its mechanism of action remains unclear.

PURPOSE

This study aims to assess the ability of BSD to therapy IBS-D and to elucidate the underlying mechanism.

METHODS

First, comprehensive analyses, including ADME (absorption, distribution, metabolism, excretion) screening, Venn analysis, Gene Ontology (GO) analysis, and network construction, were performed to characterize IBS-D-related pathways and explore the synergistic effects of BSD active compounds. Next, an IBS-D model was constructed using a three-factor superposition method of neonatal maternal separation, chronic immobilization stress stimulation, and Sennae folium aqueous extract lavage. Moreover, the impact of BSD was assessed based on the body weight, fecal water content, and abdominal withdrawal reflex (AWR), and the results of the open field test, sucrose preference test, intestinal permeability assessment, transmission electron microscopy, and TdT-mediated dUTP nick-end labeling (TUNEL) analysis. The factors that regulate the BSD effects on IBS-D were estimated using immunoblotting, quantitative reverse transcription polymerase chain reaction (q-RTPCR), immunohistochemistry, and transcriptome sequencing analyses.

RESULTS

We found that BSD improved depressive behavior, brain-gut peptide levels, and intestinal permeability induced by IBS-D by increasing the abundance of intestinal tight junctions. In addition, BSD reduced secretory immunoglobulin A levels and the number of intestinal mast cells in IBS-D rats. Network pharmacology and transcriptome sequencing analysis further revealed that the forkhead box O (FoxO) signaling pathway contributed to the BSD-induced alleviation of IBS-D, as BSD regulated the protein and mRNA levels of FoxO1, glycogen synthase kinase 3β, and FoxO3a. Importantly, a FoxO1 inhibitor effectively alleviated IBS-D symptoms in rats, whereas a FoxO3a agonist had the opposite effects.

CONCLUSION

These results demonstrate that BSD alleviates depression and intestinal symptoms by regulating brain-gut peptide expression and restoring the intestinal barrier function via the FoxO signaling pathway. Furthermore, our study uses serum pharmacochemistry technology to analyze the in vivo components of TCM formula under effective condition, solving the problem of the discovery of the effective components of TCM to some extent.

Alteration of intestinal mucosal microbiota in mice with Chinese dampness-heat syndrom diarrhea by improper diet combined with high temperature and humidity environments

Background

Environment, diet, and emotion may trigger diarrhea, but the mechanism is unclear. Dietary habits or environmental factors affect the composition of gut microbiota. This study aimed to investigate the effects of improper diet combined with high humidity and temperature (HTH) environment on the intestinal mucosal microbiota.

Materials and methods

Kunming mice were randomly assigned to two equal groups of five mice, namely the control (ccm) group and the model (cmm) group. Diarrhea mice with dampness-heat (DSH) were established by improper diet combined with HTH environments. We used 16S rRNA gene amplicon sequencing to analyze the characteristics of intestinal mucosal microbiota and the interaction relationship of function.

Results

Our study shows that the intestinal mucosal microbiota of mice changed significantly after an improper diet combined with the HTH environments. The abundance of Fusobacteria and Haemophilus increased dramatically in the cmm group compared to the ccm group (P<0.05). And the abundance of Firmicutes, Lactobacillus, and Lonsdalea was significantly decreased in the cmm group (P<0.05). According to the functional predictive analysis, we found that Lactobacillus showed a significant negative correlation with Protein export, Homologous recombination, Phenylalanine, tyrosine, tryptophan biosynthesis, Citrate cycle, and Lipoic acid metabolism.

Conclusion

Diarrhea with DSH constructed under improper diet and HTH environment may be related to Lactobacillus and Haemophilus. And long-term consumption of improper diet and the HTH environment may affect metabolism.

Intestinal IgA-Coated Bacteria in Healthy- and Altered-Microbiomes (Dysbiosis) and Predictive Value in Successful Fecal Microbiota Transplantation

IgA-coated bacteria in the gut (IgA-biome) provide a homeostatic function in healthy people through inhibition of microbial invaders and by protecting the epithelial monolayer of the gut. The laboratory methods used to detect this group of bacteria require flow cytometry and DNA sequencing (IgA-Seq). With dysbiosis (reduced diversity of the microbiome), the IgA-biome also is impaired. In the presence of enteric infection, oral vaccines, or an intestinal inflammatory disorder, the IgA-biome focuses on the pathogenic bacteria or foreign antigens, while in other chronic diseases associated with dysbiosis, the IgA-biome is reduced in capacity. Fecal microbiota transplantation (FMT), the use of fecal product from well-screened, healthy donors administered to patients with dysbiosis, has been successful in engrafting the intestine with healthy microbiota and metabolites leading to improve health. Through FMT, IgA-coated bacteria have been transferred to recipients retaining their immune coating. The IgA-biome should be evaluated in FMT studies as these mucosal-associated bacteria are more likely to be associated with successful transplantation than free luminal organisms. Studies of the microbiome pre- and post-FMT should employ metagenomic methods that identify bacteria at least at the species level to better identify organisms of interest while allowing comparisons of microbiota data between studies.

Compound mycotoxin detoxifier alleviating aflatoxin B1 toxic effects on broiler growth performance, organ damage and gut microbiota

The aim of this study was to evaluate the effects of compound mycotoxin detoxifier (CMD) on alleviating the toxic effect of aflatoxin B₁ (AFB₁) for broiler growth performance. One-kilogram CMD consists of 667 g aflatoxin B₁-degrading enzyme (ADE, 1,467 U/g), 200 g montmorillonite and 133 g compound probiotics (CP). The feeding experiment was divided into 2 stages (1-21 d and 22-42 d). In the early stage, a total of 300 one-day-old Ross broilers were randomly divided into 6 groups, 5 replications for each group, 10 broilers (half male and half female) in each replication. In the later feeding stage, about 240 twenty-two-day-old Ross broilers were randomly divided into 6 groups, 8 replications for each group, 5 broilers in each replication. Group A: basal diet; group B: basal diet with 40 μg/kg AFB₁; group C: basal diet with 1 g/kg CMD; groups D, E, and F: basal diet with 40 μg/kg AFB₁ plus 0.5, 1.0 and 1.5 g/kg CMD, respectively. The results indicated that AFB₁ significantly decreased average daily gain (ADG), protein metabolic rate, organ index of thymus, bursa of Fabricius (BF), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and catalase activities in serum, and increased AFB₁ residues in serum and liver (P < 0.05). Hematoxylin-Eosin (HE) staining analysis of jejunum, liver and kidney showed that AFB₁ caused the main pathological changes with different degrees of inflammatory cell infiltration. However, CMD additions could alleviate the negative effects of AFB₁ on the above parameters. The gut microbiota analysis indicated that AFB₁ could significantly increase the abundances of Staphylococcus-xylosu, Esherichia-coli-g-Escherichia-Shigella, and decrease Lactobacillus-aviarius abundance (P < 0.05), but which were adjusted to almost the same levels as the control group by CMD addition. The correlative analysis showed that Lactobacillus-aviarius abundance was positively correlated with ADG, SOD and BF (P < 0.05), whereas Staphylococcus-xylosus abundance was positively correlated with AFB₁ residues in serum and liver (P < 0.05). In conclusion, CMD could keep gut microbiota stable, alleviate histological lesions, increase growth performance, and reduce mycotoxin toxicity. The optimal CMD addition should be 1 g/kg in AFB₁-contaminated broilers diet.

IgA in human health and diseases: Potential regulator of commensal microbiota

Gut microbiota has extensive and tremendous impacts on human physiology and pathology. The regulation of microbiota is therefore a cardinal problem for the mutualistic relationship, as both microbial overgrowth and excessive immune reactions toward them could potentially be detrimental to host homeostasis. Growing evidence suggests that IgA, the most dominant secretory immunoglobulin in the intestine, regulates the colonization of commensal microbiota, and consequently, the microbiota-mediated intestinal and extra-intestinal diseases. In this review, we discuss the interactions between IgA and gut microbiota particularly relevant to human pathophysiology. We review current knowledge about how IgA regulates gut microbiota in humans and about the molecular mechanisms behind this interaction. We further discuss the potential role of IgA in regulating human diseases by extrapolating experimental findings, suggesting that IgA can be a future therapeutic strategy that functionally modulates gut microbiota.

Constitution of mucosa‐associated microbiota in the lower digestive tract does not change in early stage of non‐alcoholic fatty liver disease with fecal dysbiosis

Background and Aim

Methods

Results

Conclusion

Detection of Intestinal Dysbiosis in Post-COVID-19 Patients One to Eight Months after Acute Disease Resolution

The intestinal microbiota plays an important role in the immune response against viral infections, modulating both innate and adaptive immune responses. The cytokine storm is associated with COVID-19 severity, and the patient's immune status is influenced by the intestinal microbiota in a gut-lung bidirectional interaction. In this study, we evaluate the intestinal microbiota of Brazilian patients in different post-COVID-19 periods, and correlate this with clinical data and the antibiotic therapy used during the acute phase. DNA extracted from stool samples was sequenced and total anti-SARS-CoV-2 antibodies and C-reactive protein were quantified. Compared with controls, there were significant differences in the microbiota diversity in post-COVID-19 patients, suggesting an intestinal dysbiosis even several months after acute disease resolution. Additionally, we detected some genera possibly associated with the post-COVID-19 dysbiosis, including Desulfovibrio, Haemophillus, Dialister, and Prevotella, in addition to decreased beneficial microbes, associated with antibiotic-induced dysbiosis, such as Bifidobacterium and Akkermansia. Therefore, our hypothesis is that dysbiosis and the indiscriminate use of antibiotics during the pandemic may be associated with post-COVID-19 clinical manifestations. In our study, 39% (n = 58) of patients reported symptoms, including fatigue, dyspnea, myalgia, alopecia, anxiety, memory loss, and depression. These data suggest that microbiota modulation may represent a target for recovery from acute COVID-19 and a therapeutic approach for post-COVID-19 sequelae.

Mucosal Plasma Cell Activation and Proximity to Nerve Fibres Are Associated with Glycocalyx Reduction in Diarrhoea-Predominant Irritable Bowel Syndrome: Jejunal Barrier Alterations Underlying Clinical Manifestations

Irritable bowel syndrome (IBS) is a disorder of brain-gut interaction characterised by abdominal pain and changes in bowel habits. In the diarrhoea subtype (IBS-D), altered epithelial barrier and mucosal immune activation are associated with clinical manifestations. We aimed to further evaluate plasma cells and epithelial integrity to gain understanding of IBS-D pathophysiology. One mucosal jejunal biopsy and one stool sample were obtained from healthy controls and IBS-D patients. Gastrointestinal symptoms, stress, and depression scores were recorded. In the jejunal mucosa, RNAseq and gene set enrichment analyses were performed. A morphometric analysis by electron microscopy quantified plasma cell activation and proximity to enteric nerves and glycocalyx thickness. Immunoglobulins concentration was assessed in the stool. IBS-D patients showed differential expression of humoral pathways compared to controls. Activation and proximity of plasma cells to nerves and IgG concentration were also higher in IBS-D. Glycocalyx thickness was lower in IBS-D compared to controls, and this reduction correlated with plasma cell activation, proximity to nerves, and clinical symptoms. These results support humoral activity and loss of epithelial integrity as important contributors to gut dysfunction and clinical manifestations in IBS-D. Additional studies are needed to identify the triggers of these alterations to better define IBS-D pathophysiology.

The difference of disrupted rhythms of life, work and entertainment between patients with FGIDs and healthy people and their associations with psychological disorders under COVID-19 pandemic

AIMS

To investigate the differences in disrupted rhythms between healthy people and patients with functional gastrointestinal disorders (FGIDs) and their associations with mood disorders during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

The rhythm scales were composed of subscales 1 and 2 for the assessment of life-work and entertainment rhythms, respectively; Zung's Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) were used to assess mood disorders.

RESULTS

A total of 671 patients with FGIDs and 4373 healthy people successfully participated. The scores of subscales 1 and 2 for patients with FGIDs were significantly higher than those for healthy people (p < .005). The SAS and SDS scores, their prevalence rates were significantly higher than those for the healthy group (all p < .001). Health status, current occupation, life-work rhythm, SDS, and SAS were independent related factors of FGIDs. The score of life-work-entertainment rhythm was significantly positively correlated with SDS and SAS (both p < .001).

CONCLUSION

Disrupted rhythms in patients with FGIDs under the COVID-19 pandemic were more frequently and significantly positively associated with mood disorders.

Effect of Shugan Jianpi Recipe Combined with Cross Moxibustion on Biochemical Examination Indexes and Total Score of TCM Symptoms in Patients with Spleen-Stomach Damp-Heat Diarrhea Irritable Bowel Syndrome

Objective

To explore the effect of Shugan Jianpi recipe combined with cross moxibustion on biochemical examination indexes and total score of TCM symptoms in patients with spleen-stomach damp-heat diarrhea irritable bowel syndrome (IBS).

Methods

Sixty patients with spleen-stomach damp-heat diarrhea (IBS) treated in our hospital from January 2019 to September 2021 were enrolled. The patients were randomly assigned into the control group and study group. The control group was treated with Chang Shugan Jianpi recipe, and the study group was treated with Shugan Jianpi recipe combined with cross moxibustion. The curative effect, single symptom score, total score of TCM clinical symptoms, plasma gastrointestinal hormone level, IBS-QOL score, and recurrence were compared.

Results

First of all, we compared the curative effects. The study group was significantly effective in 24 cases, effective in 5 cases, and ineffective in 1 case, and the effective rate was 96.67%. In the control group, 13 cases were markedly effective, 10 cases were effective, and 7 cases were ineffective, and the effective rate was 76.67%. The effective rate of the study group was higher compared to the control group (P < 0.05). Secondly, the individual symptom scores were compared. Compared between the two groups, the scores of diarrhea times, stool characteristics, abdominal pain, and abdominal distension in the study group were lower compared to the control group (P < 0.05). After treatment, the total score of TCM clinical symptoms decreased. Compared between the two groups, the total score of TCM clinical symptoms in the study group was lower compared to the control group at 1 week, 2 weeks, and 4 weeks after treatment (P < 0.05). After treatment, the levels of 5-HT and VIP decreased. The levels of 5-HT and VIP in the study group were lower compared to the control group (P < 0.05). The scores of anxieties, health worry, behavioral disorder, social reaction, somatic intention, interpersonal relationship, dietary concern, and sexual behavior in the study group were lower compared to the control group. The IBS-QOL scores were significantly lower compared to the control group (P < 0.05). Finally, we compared the recurrence. The recurrence rate in the study group was lower compared to the control group (P < 0.05).

Conclusion

The prescription combined with cross moxibustion has the effect of soothing the liver and invigorating the spleen, resolving dampness and stomach, and can reduce the main clinical symptoms of patients with diarrhea IBS of spleen-stomach damp-heat type, and the overall effect is significant. It can also enhance the emotional state of anxiety and depression and achieve the overall psychological and physical balance and health state, and the recurrence rate is low, which can be further applied in clinic.

Immune responses in the irritable bowel syndromes: time to consider the small intestine

BACKGROUND

Irritable bowel syndrome (IBS) is considered a disorder of gut-brain interaction (DGBI), presenting as chronic abdominal pain and altered defaecation. Symptoms are often food related. Much work in the field has focused on identifying physiological, immune and microbial abnormalities in the colon of patients; however, evidence of small intestinal immune activation and microbial imbalance has been reported in small studies. The significance of such findings has been largely underappreciated despite a growing body of work implicating small intestinal homeostatic imbalance in the pathogenesis of DGBIs.

MAIN TEXT

Small intestinal mechanosensation is a characteristic feature of IBS. Furthermore, altered small intestinal barrier functions have been demonstrated in IBS patients with the diarrhoea-predominant subtype. Small intestinal bacterial overgrowth and increased populations of small intestinal mast cells are frequently associated with IBS, implicating microbial imbalance and low-grade inflammation in the pathogenesis of IBS. Furthermore, reports of localised food hypersensitivity responses in IBS patients implicate the small intestine as the site of immune-microbial-food interactions.

CONCLUSIONS

Given the association of IBS symptoms with food intake in a large proportion of patients and the emerging evidence of immune activation in these patients, the current literature suggests the pathogenesis of IBS is not limited to the colon but rather may involve dysfunction of the entire intestinal tract. It remains unclear if regional variation in IBS pathology explains the various symptom phenotypes and further work should consider the intestinal tract as a whole to answer this question.

Gut Microbiome and Neuroinflammation in Hypertension

Hypertension is a worldwide problem with major impacts on health including morbidity and mortality, as well as consumption of health care resources. Nearly 50% of American adults have high blood pressure, and this rate is rising. Even with multiple antihypertensive drugs and aggressive lifestyle modifications, blood pressure is inadequately controlled in about 1 of 5 hypertensive individuals. This review highlights a hypothesis for hypertension that suggests alternative mechanisms for blood pressure elevation and maintenance. A better understanding of these mechanisms could open avenues for more successful treatments. The hypothesis accounts for recent understandings of the involvement of gut physiology, gut microbiota, and neuroinflammation in hypertension. It includes bidirectional communication between gut microbiota and gut epithelium in the gut-brain axis that is involved in regulation of autonomic nervous system activity and blood pressure control. Dysfunction of this gut-brain axis, including dysbiosis of gut microbiota, gut epithelial dysfunction, and deranged input to the brain, contributes to hypertension via inflammatory mediators, metabolites, bacteria in the circulation, afferent information alterations, etc resulting in neuroinflammation and unbalanced autonomic nervous system activity that elevates blood pressure. This in turn negatively affects gut function and its microbiota exacerbating the problem. We focus this review on the gut-brain axis hypothesis for hypertension and possible contribution to racial disparities in hypertension. A novel idea, that immunoglobulin A-coated bacteria originating in the gut with access to the brain could be involved in hypertension, is raised. Finally, minocycline, with its anti-inflammatory and antimicrobial properties, is evaluated as a potential antihypertensive drug acting on this axis.

Cocultivation of Chinese prescription and intestine microbiota: SJZD alleviated the major symptoms of IBS-D subjects by tuning neurotransmitter metabolism

OBJECTIVE

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a recurrent and common disease featuring dysbiotic intestinal microbiota, with limited treatments. Si-Jun-Zi Decoction (SJZD), a classic Chinese prescription, has been extensively used for IBS-D. This work aimed to explore the ex vivo interactions of SJZD and IBS-D's intestinal microbiota.

METHODS

Five samples of intestinal microbiota collected from IBS-D volunteers and five age-matched healthy controls were recruited from the Affiliated Hospital, Chengdu University of Traditional Chinese Medicine (TCM). A representative mixture of intestinal microbiota was composed of an equal proportion of these fecal samples. To simulate the clinical interaction, this microbiota was cocultivated with SJZD at clinical dosage in an anaerobic incubator at 37°C for 35 h. Microbiota and metabolic alterations were assessed by 16S rRNA gene sequencing in the V3/V4 regions and a nontargeted metabolome platform, respectively.

RESULTS

After being cocultivated with SJZD, the dysbiotic intestine microbiota from IBS-D subjects was largely restored to those of the healthy controls. A total of 624 differentially expressed metabolites were detected by nontargeted metabolomics, of which 16 biomarkers were identified. These metabolites were then enriched into 11 pathways by KEGG, particularly those involved in neurotransmitter metabolism responses for the major symptom of IBS-D. Correlation analysis of bacterial metabolites demonstrated a synergistic pattern of neurotransmitter metabolism between Streptococcus and E. Shigella.

CONCLUSION

SJZD rescued the dysbiotic intestinal microbiota and ameliorated the dysfunctional neurotransmitter metabolism involved in IBS-D's major symptoms.

Gut microbiome characteristics of comorbid generalized anxiety disorder and functional gastrointestinal disease: Correlation with alexithymia and personality traits

OBJECTIVE

The aim of this study was to investigate the characteristics of intestinal flora in patients with functional gastroenteropathy and generalized anxiety disorder (GAD) and the relationship between intestinal flora and psychological factors.

MATERIALS AND METHODS

From March 2020 to December 2020, a total of 35 patients with functional gastroenteropathy and generalized anxiety disorder, 30 healthy controls, 16 patients with functional gastroenteropathy, and 44 patients with generalized anxiety disorder were selected from the Affiliated Hospital of Guizhou Medical University. Fecal samples were collected from each group, and the related psychophysiological factors scales (Hamilton Anxiety Scale, Hamilton Depression Scale, Neurotic Personality Questionnaire, concept of illness questionnaire, Toronto Alexithymia Scale, Severity of Physical Symptoms Scale, and Cognitive Emotion Regulation Questionnaire) were improved. 16S rRNA high-pass sequencing was used to determine the correlation between intestinal flora changes and functional gastroenteropathy with generalized anxiety disorder. Then, the scale and gut microbiota results were analyzed for correlation to determine the correlation between personality traits and gut microbiota.

RESULTS

We found similar intestinal microbiota in patients with functional gastroenterology, generalized anxiety disorder, and functional gastroenteropathy with generalized anxiety disorder. But the relative abundance of Clostridium was significantly increased in patients with functional gastrointestinal disease (FGID) and generalized anxiety. The relative abundance of Haemophilus influenzae was significantly increased in patients with functional gastrointestinal disease without a generalized anxiety disorder. The intestinal microecological composition was significantly correlated with personality traits.

CONCLUSION

Functional gastrointestinal disease comorbidity GAD may be related to an increase in the relative abundance of Fusobacterium. FGID non-comorbidity GAD may be related to the increased relative abundance of Hemophilus. The increased relative abundance of Fusobacterium and Megamonas is associated with personality traits such as difficulty describing feelings and difficulty identifying feelings, neuroticism, and negative cognition of disease.

Lactobacillus plantarum CCFM1143 Alleviates Chronic Diarrhea via Inflammation Regulation and Gut Microbiota Modulation: A Double-Blind, Randomized, Placebo-Controlled Study

Irritable bowel syndrome with diarrhea and functional diarrhea are both functional bowel disorders that cause chronic diarrhea. Chronic diarrhea is closely related to daily life and the psychological condition of diarrhea in patients, and probiotics can play a significant role in alleviating chronic diarrhea in some research. Lactobaccilus plantarum CCFM1143 can relieve diarrhea in mice caused by enterotoxigenic Escherichia coli (ETEC); however, its clinical effects remain unclear. This study aimed to assess the effects of CCFM1143 as a therapy for chronic diarrhea patients. Fifty-five patients with chronic diarrhea were randomly assigned into the probiotic group (n = 28) and the placebo group (n = 27), receiving the routine regimen with or without probiotics for 4 weeks, respectively. CCFM1143 can mitigate the apparent clinical symptoms and improve the health status and quality of life of patients. In addition, it could inhibit the increase in interleukin 6 (IL-6) and the decrease in motilin; modulate the short-chain fatty acids, especially acetic and propionic acids; and regulate the gut microbiota, particularly reducing the abundance of Bacteroides and Eggerthella and enriching the abundance of Akkermansia, Anaerostipes, and Terrisporobacter. In addition, treatment with probiotics showed clinical effectiveness in managing chronic diarrhea when compared with the placebo group. The findings could help to develop and further the application of probiotics for chronic diarrhea.

Gut microbiota is involved in the antidepressant-like effect of (S)-norketamine in an inflammation model of depression

The non-competitive glutamatergic N-methyl-d-aspartate receptor (NMDAR) antagonist, (R, S)-ketamine (ketamine), is known to exert rapid and long-lasting antidepressant-like effects. However, the widely use of ketamine is restricted owing to severe psychotomimetic side-effects and abuse liability. Very recently, we demonstrated that a major metabolite of ketamine, norketamine, in particular the (S)-enantiomer, had a potent antidepressant-like effect. We here examined the effects of a low-dose of norketamine enantiomers on depression symptoms and detected the changes in the composition of gut microbiota. In the behavioral tests, (S)-norketamine, but not (R)-norketamine, showed antidepressant-like effects in the lipopolysaccharide (LPS)-induced mice. At the genus level, (S)-norketamine, but not (R)-norketamine, significantly attenuated the increase in the levels of Escherichia-Shigella and Adlercreutzia, as well as the reduction in the levels of Harryflintia. At the species level, both (S)-norketamine and (R)-norketamine significantly attenuated the increase in the levels of bacterium ic1379 and Bacteroides sp. Marseille-P3166. Notably, (S)-norketamine was more potent than (R)-norketamine at reducing the levels of bacterium ic1379 and Bacteroides sp. Marseille-P3166. Furthermore, (S)-norketamine, but not (R)-norketamine, significantly attenuated the increased levels of Bacteroides caecigallinarum. In conclusion, this study suggests that the antidepressant-like effects of (S)-norketamine might be associated with the changes in the composition of gut microbiota. Therapeutic strategies improving the gut microbiota might facilitate the benefits for depression treatment.

Intestinal Homeostasis under Stress Siege

Intestinal homeostasis encompasses a complex and balanced interplay among a wide array of components that collaborate to maintain gut barrier integrity. The appropriate function of the gut barrier requires the mucus layer, a sticky cushion of mucopolysaccharides that overlays the epithelial cell surface. Mucus plays a critical anti-inflammatory role by preventing direct contact between luminal microbiota and the surface of the epithelial cell monolayer. Moreover, mucus is enriched with pivotal effectors of intestinal immunity, such as immunoglobulin A (IgA). A fragile and delicate equilibrium that supports proper barrier function can be disturbed by stress. The impact of stress upon intestinal homeostasis results from neuroendocrine mediators of the brain-gut axis (BGA), which comprises a nervous branch that includes the enteric nervous system (ENS) and the sympathetic and parasympathetic nervous systems, as well as an endocrine branch of the hypothalamic-pituitary-adrenal axis. This review is the first to discuss the experimental animal models that address the impact of stress on components of intestinal homeostasis, with special emphasis on intestinal mucus and IgA. Basic knowledge from animal models provides the foundations of pharmacologic and immunological interventions to control disturbances associated with conditions that are exacerbated by emotional stress, such as irritable bowel syndrome.

The gut microbiota is associated with the small intestinal paracellular permeability and the development of the immune system in healthy children during the first two years of life

BACKGROUND

The intestinal barrier plays an important role in the defense against infections, and nutritional, endocrine, and immune functions. The gut microbiota playing an important role in development of the gastrointestinal tract can impact intestinal permeability and immunity during early life, but data concerning this problem are scarce.

METHODS

We analyzed the microbiota in fecal samples (101 samples in total) collected longitudinally over 24 months from 21 newborns to investigate whether the markers of small intestinal paracellular permeability (zonulin) and immune system development (calprotectin) are linked to the gut microbiota. The results were validated using data from an independent cohort that included the calprotectin and gut microbiota in children during the first year of life.

RESULTS

Zonulin levels tended to increase for up to 6 months after childbirth and stabilize thereafter remaining at a high level while calprotectin concentration was high after childbirth and began to decline from 6 months of life. The gut microbiota composition and the related metabolic potentials changed during the first 2 years of life and were correlated with zonulin and calprotectin levels. Faecal calprotectin correlated inversely with alpha diversity (Shannon index, r = - 0.30, FDR P (Q) = 0.039). It also correlated with seven taxa; i.a. negatively with Ruminococcaceae (r = - 0.34, Q = 0.046), and Clostridiales (r = - 0.34, Q = 0.048) and positively with Staphylococcus (r = 0.38, Q = 0.023) and Staphylococcaceae (r = 0.35, Q = 0.04), whereas zonulin correlated with 19 taxa; i.a. with Bacillales (r = - 0.52, Q = 0.0004), Clostridiales (r = 0.48, Q = 0.001) and the Ruminococcus (torques group) (r = 0.40, Q = 0.026). When time intervals were considered only changes in abundance of the Ruminococcus (torques group) were associated with changes in calprotectin (β = 2.94, SE = 0.8, Q = 0.015). The dynamics of stool calprotectin was negatively associated with changes in two MetaCyc pathways: pyruvate fermentation to butanoate (β = - 4.54, SE = 1.08, Q = 0.028) and Clostridium acetobutylicum fermentation (β = - 4.48, SE = 1.16, Q = 0.026).

CONCLUSIONS

The small intestinal paracellular permeability, immune system-related markers and gut microbiota change dynamically during the first 2 years of life. The Ruminococcus (torques group) seems to be especially involved in controlling paracellular permeability. Staphylococcus, Staphylococcaceae, Ruminococcaceae, and Clostridiales, may be potential biomarkers of the immune system. Despite observed correlations their clear causation and health consequences were not proven. Mechanistic studies are required.

Co-Occurrence of Symptoms and Gut Microbiota Composition Before Neoadjuvant Chemotherapy and Radiation Therapy for Rectal Cancer: A Proof of Concept

PURPOSE

To examine a) whether there are significant differences in gut microbial diversity and in the abundance of gut microbial taxa; and b) differences in predicted functional pathways of the gut microbiome between those participants with high co-occurring symptoms and those with low co-occurring symptoms, prior to neoadjuvant chemotherapy and radiation therapy (CRT) for rectal cancer.

METHODS

Rectal cancer patients (n = 41) provided stool samples for 16 S rRNA gene sequencing and symptom ratings for fatigue, sleep disturbance, and depressive symptoms prior to CRT. Descriptive statistics were computed for symptoms. Gut microbiome data were analyzed using QIIME2, LEfSe, and the R statistical package.

RESULTS

Participants with high co-occurring symptoms (n = 19) had significantly higher bacterial abundances of Ezakiella, Clostridium sensu stricto, Porphyromonas, Barnesiella, Coriobacteriales Incertae Sedis, Synergistiaceae, Echerichia-Shigella, and Turicibacter compared to those with low co-occurring symptoms before CRT (n = 22). Biosynthesis pathways for lipopolysaccharide, L-tryptophan, and colanic acid building blocks were enriched in participants with high co-occurring symptoms. Participants with low co-occurring symptoms showed enriched abundances of Enterococcus and Lachnospiraceae, as well as pathways for β-D-glucoronosides, hexuronide/hexuronate, and nicotinate degradation, methanogenesis, and L-lysine biosynthesis.

CONCLUSION

A number of bacterial taxa and predicted functional pathways were differentially abundant in patients with high co-occurring symptoms compared to those with low co-occurring symptoms before CRT for rectal cancer. Detailed examination of bacterial taxa and pathways mediating co-occurring symptoms is warranted.

Impact of Diabetes on the Gut and Salivary IgA Microbiomes

Mucosal surfaces like those present in the lung, gut, and mouth interface with distinct external environments. These mucosal gateways are not only portals of entry for potential pathogens but also homes to microbial communities that impact host health. Secretory immunoglobulin A (SIgA) is the single most abundant acquired immune component secreted onto mucosal surfaces and, via the process of immune exclusion, shapes the architecture of these microbiomes. Not all microorganisms at mucosal surfaces are targeted by SIgA; therefore, a better understanding of the SIgA-coated fraction may identify the microbial constituents that stimulate host immune responses in the context of health and disease. Chronic diseases like type 2 diabetes are associated with altered microbial communities (dysbiosis) that in turn affect immune-mediated homeostasis. 16S rRNA gene sequencing of SIgA-coated/uncoated bacteria (IgA-Biome) was conducted on stool and saliva samples of normoglycemic participants and individuals with prediabetes or diabetes (n = 8/group). These analyses demonstrated shifts in relative abundance in the IgA-Biome profiles between normoglycemic, prediabetic, or diabetic samples distinct from that of the overall microbiome. Differences in IgA-Biome alpha diversity were apparent for both stool and saliva, while overarching bacterial community differences (beta diversity) were also observed in saliva. These data suggest that IgA-Biome analyses can be used to identify novel microbial signatures associated with diabetes and support the need for further studies exploring these communities. Ultimately, an understanding of the IgA-Biome may promote the development of novel strategies to restructure the microbiome as a means of preventing or treating diseases associated with dysbiosis at mucosal surfaces.

No Impact of Long-Term Fingolimod Treatment on Fecal Secretory Immunoglobulin A Levels in Patients With Multiple Sclerosis

Background

Fingolimod (FTY) is a sphingosine 1 phosphate (S1P) agonist with significant effects on immune cell distribution used as an effective disease modifying therapy in multiple sclerosis (MS) patients. Animal studies have demonstrated that a dysregulation of egress of murine secretory Immunglobulin A (sIgA)+ plasmablasts from Peyer’s patches in FTY-treated mice reduced fecal sIgA levels. Alterations in intestinal levels of sIgA could modify the gut microbiome and homeostasis in humans. We analyzed the effect of FTY on the fecal and salivary sIgA levels as marker of the humoral immune system in the gut.

Methods

Twenty five people with confirmed MS diagnosis according to 2010 revised McDonald’s criteria and on long-term continuous treatment at the MS Center in Dresden, Germany were enrolled in this exploratory cross-sectional study. Fecal and salivary sIgA were analyzed after at least 12 months of treatment with FTY or Glatiramer acetate (GA).

Results

Fifteen MS patients on FTY and 10 on GA participated in this study. The mean fecal sIgA concentration of both groups was not decreased compared to reference values and did not demonstrate significant differences between them (FTY 3323.13 μg/g +/− 2094.72; GA 2040.65 μg/g +/− 1709.07). A similar pattern was seen in the salivary sIgA and serum immunoglobulins levels.

Conclusion

In this pilot study, we could not confirm the decrease of fecal sIgA after a long-term treatment with FTY. Further longitudinal studies should evaluate the effects of MS treatments on the gut immune system in more detail.

A Potential Role for Stress-Induced Microbial Alterations in IgA-Associated Irritable Bowel Syndrome with Diarrhea

Stress is a known trigger for flares of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS); however, this process is not well understood. Here, we find that restraint stress in mice leads to signs of diarrhea, fecal dysbiosis, and a barrier defect via the opening of goblet-cell associated passages. Notably, stress increases host immunity to gut bacteria as assessed by immunoglobulin A (IgA)-bound gut bacteria. Stress-induced microbial changes are necessary and sufficient to elicit these effects. Moreover, similar to mice, many diarrhea-predominant IBS (IBS-D) patients from two cohorts display increased antibacterial immunity as assessed by IgA-bound fecal bacteria. This antibacterial IgA response in IBS-D correlates with somatic symptom severity and was distinct from healthy controls or IBD patients. These findings suggest that stress may play an important role in patients with IgA-associated IBS-D by disrupting the intestinal microbial community that alters gastrointestinal function and host immunity to commensal bacteria.

Stress in mice causes diarrhea, dysbiosis, barrier defect, increased antibacterial IgA

Stress-induced microbial changes are sufficient to elicit the above effects

IBS-D patients from two cohorts display increased and unique antibacterial IgA

Antibacterial IgA in IBS-D correlates with patient symptom severity