Mucosa-associated gut microbiota reflects clinical course of ulcerative colitis

Alzheimer's Disease-Derived Outer Membrane Vesicles Exacerbate Cognitive Dysfunction, Modulate the Gut Microbiome, and Increase Neuroinflammation and Amyloid-β Production

Although our understanding of the molecular biology of Alzheimer's disease (AD) continues to improve, the etiology of the disease, particularly the involvement of gut microbiota disturbances, remains a challenge. Outer membrane vesicles (OMVs) play a key role in central nervous system diseases, but the impact of OMVs on AD progression remains unclear. In this study, we hypothesized that AD-derived OMVs (OMVsAD) were a risk factor in AD pathology. To test our hypothesis, young APP/PS1 mice (AD mice) were given OMVsAD by gavage. Young AD mice were euthanized 120 days after gavage to assess the intestinal barrier, gut microbiota diversity, mediators of neuroinflammation, glial markers, amyloid burden, and short-chain fatty acid (SCFA) levels. Our results showed that OMVsAD accelerated cognitive dysfunction after 120 days of intragastric administration. Morris water maze experiment and new object recognition test showed that OMVsAD caused significantly poorer spatial ability learning and memory of the AD mice. We observed the OMVsAD-treated APP/PS1 mice display OMVs disrupting the intestinal barrier compared with controls of normal human-derived OMVs. Compared with the OMVsHC group, claudin-5 and ZO-1 related to the intestinal barrier were significantly downregulated in the OMVsAD group. The OMVsAD activate microglia in the cerebral cortex and hippocampus of AD mice, and the levels of IL-1β, IL-6, TNF-α, and NF-Κb were upregulated. We also found that OMVsAD increased Aβ production. 16S rRNA sequencing showed that OMVsAD negatively regulated the α- and β-diversity index of intestinal flora and reduced the levels of SCFA. OMVsAD may change the intestinal flora of young AD, damage the intestinal mucosa and blood-brain barrier, and accelerate AD neuropathological damage.

Recent developments in managing luminal microbial ecology in patients with inflammatory bowel disease: from evidence to microbiome-based diagnostic and personalized therapy

INTRODUCTION

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic condition characterized by abnormal immune responses and intestinal inflammation. Emerging evidence highlights the vital role of gut microbiota in IBD's onset and progression. Recent advances have shaped diagnostic and therapeutic strategies, increasingly focusing on microbiome-based personalized care. Methodology: this review covers studies from 2004 to 2024, reflecting the surge in research on luminal microbial ecology in IBD. Human studies were prioritized, with select animal studies included for mechanistic insights. Only English-language, peer-reviewed articles - clinical trials, systematic reviews, and meta-analyses - were considered. Studies without clinical validation were excluded unless offering essential insights. Searches were conducted using PubMed, Scopus, and Web of Science.

AREAS COVERED

we explore mechanisms for managing IBD-related microbiota, including microbial markers for diagnosis and novel therapies such as fecal microbiota transplantation, metabolite-based treatments, and precision microbiome modulation. Additionally, we review technologies and diagnostic tools used to analyze gut microbiota composition and function in clinical settings. Emerging data supporting personalized therapeutic strategies based on individual microbial profiles are discussed.

EXPERT OPINION

Standardized microbiome research integration into clinical practice will enhance precision in IBD care, signaling a shift toward microbiota-based personalized medicine.

Importance of rectal over colon status in ulcerative colitis remission: the role of microinflammation and mucosal barrier dysfunction in relapse

BACKGROUND

Ulcerative colitis (UC) is a refractory inflammatory disease that affects the rectum and colon, with pivotal involvement of the rectal environment in relapse initiation. This study was conducted in two phases to examine the differences in gene expression between the rectum and colon and to identify relapse factors.

METHODS

In ***Study 1, RNA sequencing was performed on biopsies from the colon and rectum of patients with active UC, those with remission UC, and controls. In Study 2, the mucosal impedance (MI) values reflecting mucosal barrier function and the mRNA expression of tight junction proteins and inflammatory cytokines were examined in 32 patients with remission UC and 22 controls. Relapse was monitored prospectively.

RESULTS

In Study 1, comprehensive genetic analysis using RNA sequencing revealed distinct gene profiles in the rectum and sigmoid colon of patients with remission UC. The rectum of these patients exhibited an enriched immune response and apical junction phenotype with persistent upregulation of CLDN2 gene expression. In Study 2, even in patients with remission UC, the MI values in the rectum, but not in the sigmoid colon, were significantly decreased, whereas they were negatively correlated with CLDN2, IL-1β, and IL-6 expressions.

CONCLUSION

The status of the rectum in patients with remission UC differs from that of the colon, with microinflammation and impaired mucosal barrier function, which are associated with the upregulation of CLDN2, playing a role in relapse.

Bacterial membrane vesicles restore gut anaerobiosis

Inflammation damages the epithelial cell barrier, allowing oxygen to leak into the lumen of the gut. Respiring E. coli and other Enterobacteriaceae produce proinflammatory lipopolysaccharide, exacerbating inflammatory bowel disease. Here we show that respiring membrane vesicles (MV) from E. coli ameliorate symptoms in a mouse model of gut inflammation. Membrane vesicle treatment diminished weight loss and limited shortening of the colon. Notably, oxygenation of the colonic epithelium was significantly decreased in animals receiving wild type MVs, but not MVs from an E. coli mutant lacking cytochromes. Metatranscriptomic analysis of the microbiome shows an increase in anaerobic Lactobacillaceae and a decrease in Enterobacteriaceae, as well as a general shift towards fermentation in MV-treated mice. This is accompanied by a decrease in proinflammatory TNF-α. We report that MVs may lead to the development of a novel type of a therapeutic for dysbiosis, and for treating IBD.

Impact of Microbiota Diversity on Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic condition that includes two main types, Crohn's disease (CD) and ulcerative colitis (UC), involving inflammation of the gastrointestinal (GI) tract. The exact cause of IBD is unknown but could be a combination of genetic, environmental, and immune system factors. This study investigated the impact of IBD on microbiota diversity by evaluating the differences in microbial composition and the microbiota of a control group (A) of healthy individuals and a group (B) of IBD patients. Sixty biopsies were collected from participants recruited from hospitals in Makkah, Saudi Arabia. Biopsy specimens were taken during colonoscopy examination, and bacterial identification was performed by extracting ribosomal DNA from sigmoid colon biopsies using a DNeasy Blood & Tissue Kit. Metagenomics and bioinformatics analyses were then conducted to analyze and compare the microbiota in the two groups. The results showed that the varieties of core microbiome species were 3.81% greater in the IBD patients than in the members of the control group. Furthermore, the differences between the groups were significantly greater than the variations within each group. Differences between the two groups were detected in the relative abundance of Clostridium nexile, Ruminococcus gnavus, Ruminococcus faecis, and Escherichia coli. These results indicate that microbiota could play a role in the pathogenesis of IBD and suggest that microbial diversity can serve as a biomarker for diagnosing the disease and monitoring its progression.

Meta-Analysis: Exclusive Enteral Nutrition in Adults With Ulcerative Colitis

BACKGROUND

Exclusive enteral nutrition (EEN) is an established dietary therapy for Crohn's disease but its role in ulcerative colitis remains unclear.

AIMS

To investigate the efficacy of EEN in adults with active ulcerative colitis and compare variations in treatment protocols, safety, tolerability and adherence.

METHODS

We conducted a systematic search of MEDLINE, Embase, Cochrane CENTRAL, Emcare, CINAHL, Web of Science and trial registries for articles published from inception until July 21, 2024. We included all experimental and observational studies that described the use of EEN in adults with active ulcerative colitis. This review was registered on PROSPERO (CRD42022319584).

RESULTS

Of 3273 articles screened, we included 10 studies (334 adults). Overall, there was no difference between EEN and comparator for ulcerative colitis remission induction (median follow-up 14 days, risk ratio (RR) 1.15, 95% confidence interval (CI) 0.71-1.85; 2 studies). In acute severe ulcerative colitis, there was no difference between EEN and comparator for corticosteroid failure (RR 0.76, 95% CI 0.48-1.20; 2 studies) or risk of colectomy (RR 0.88, 95% CI 0.51-1.51, n = 2 studies) during index admission. The pooled discontinuation rate was 3% (95% CI 0-10; 9 studies). There was heterogeneity in trial design, methodology and assessment of outcomes.

CONCLUSION

EEN was well tolerated with low therapy discontinuation in adults with active ulcerative colitis. However, there is insufficient evidence to support the use of EEN as an adjunctive therapy to standard of care. Further, well-designed studies with reproducible methodology and endpoints are necessary to evaluate its effectiveness.

REGISTRY NUMBER FOR SYSTEMATIC REVIEW

PROSPERO 2022 CRD42022319584.

CGRPβ suppresses the pathogenesis of ulcerative colitis via the immunoproteasome

Various factors have been implicated in the pathogenesis of ulcerative colitis (UC), with immune system failure being the most important one. Calcitonin gene-related peptide (CGRP), a neuropeptide with two isoforms, CGRPα and CGRPβ, has been reported to regulate the immune system. In this study, we investigated the role of CGRP isoforms in UC pathogenesis. We induced UC-like symptoms in CGRPα and CGRPβ knockout (KO) mice using dextran sulphate sodium. Compared to wild-type and CGRPα KO mice, CGRPβ-deficient mice exhibited severe symptoms with increased blood in the stool and diarrhoea. Proteome analysis revealed significant up-regulation of immune-related proteins and immunoproteasome components in CGRPβ-deficient mice, suggesting that an enhanced immune response contributes to the severity of this disease. Treatment with ONX-0914, an immunoproteasome inhibitor, markedly improved these symptoms, highlighting the role of the immunoproteasome in exacerbating UC. This study provides the first evidence that CGRPβ protects against UC by modulating immune responses, particularly those mediated by the immunoproteasome. Our findings suggest that functional differences in CGRP isoforms may influence the severity and management of UC. This insight into the neuro-immune mechanism of UC opens avenues for novel therapies that address both the neural and immune aspects of this disease.

Dynamics of Gut Microbiota After Fecal Microbiota Transplantation in Ulcerative Colitis: Success Linked to Control of Prevotellaceae

BACKGROUND

Fecal microbiota transplantation (FMT) is an experimental treatment for ulcerative colitis (UC). We aimed to study microbial families associated with FMT treatment success.

METHODS

We analyzed stools from 24 UC patients treated with 4 FMTs weekly after randomization for pretreatment during 3 weeks with budesonide (n = 12) or placebo (n = 12). Stool samples were collected 9 times pre-, during, and post-FMT. Clinical and endoscopic response was assessed 14 weeks after initiation of the study using the full Mayo score. Early withdrawal due to worsening of UC symptoms was classified as non-response.

RESULTS

Nine patients (38%) reached remission at week 14, and 15 patients had a partial response or non-response at or before week 14. With a Dirichlet multinomial mixture model, we identified 5 distinct clusters based on the microbiota composition of 180 longitudinally collected patient samples and 27 donor samples. A Prevotellaceae-dominant cluster was associated with poor response to FMT treatment. Conversely, the families Ruminococcaceae and Lachnospiraceae were associated with a successful clinical response. These associations were already visible at the start of the treatment for a subgroup of patients and were retained in repeated measures analyses of family-specific abundance over time. Responders were also characterized by a significantly lower Simpson dominance compared to non-responders.

CONCLUSIONS

The success of FMT treatment of UC patients appears to be associated with specific gut microbiota families, such as control of Prevotellaceae. Monitoring the dynamics of these microbial families could potentially be used to inform treatment success early during FMT.

CLINICAL TRIAL REGISTRATION NUMBER

The study was registered in the Netherlands Trial Register, with reference number NL9858.

Association between bowel movement frequency and erectile dysfunction in patients with ulcerative colitis: a cross-sectional study

The association between ulcerative colitis (UC) and erectile dysfunction (ED) has been previously reported. Numerous previous studies have also reported an association between gastrointestinal symptoms and ED. Constipation and diarrhea are common in patients with UC. However, the specific association between bowel movement frequency and ED remains unclear. The aim of this study is to investigate the association between bowel movement frequency and ED in 164 patients with UC. The definition of ED, moderate to severe ED, and severe ED was the Sexual Health Inventory for Men score <22, <12, and <8, respectively. Bowel movement frequency was divided into three categories: (1) high (More than once a day), (2) normal (once a day, reference), and low (less than one time/day). The definition of constipation was based on the Rome I criteria and/or medication for constipation. The prevalence of constipation and ED was 10.4% and 86.0%, respectively. The rate of high, normal, and low bowel movement frequency was 56.1%, 25.0%, and 18.9%, respectively. High bowel movement frequency was independently and positively associated with ED and moderate to severe ED (ED: adjusted odds ratio [OR] 4.42, 95% confidence interval [CI] 1.35-15.98; moderate to severe: adjusted OR 2.98, 95% CI 1.22-7.61). Low bowel movement frequency was independently and positively associated with moderate to severe ED and severe ED (moderate to severe: adjusted OR 3.96, 95% CI 1.27-13.08; severe: adjusted OR 3.20, 95% CI 1.08-9.86). No association between constipation and ED was found. In conclusion, in Japanese patients with UC, both high and low bowel movement frequency were independently and positively associated with ED.

Uniform bacterial genetic diversity along the guts of mice inoculated with human stool

Environmental gradients exist throughout the digestive tract, driving spatial variation in the membership and abundance of bacterial species along the gut. However, less is known about the distribution of genetic diversity within bacterial species along the gut. Understanding this distribution is important because bacterial genetic variants confer traits important for the functioning of the microbiome and are also known to impart phenotypes to the hosts, including local inflammation along the gut and the ability to digest food. Thus, to be able to understand how the microbiome functions at a mechanistic level, it is essential to understand how genetic diversity is organized along the gut and the ecological and evolutionary processes that give rise to this organization. In this study, we analyzed bacterial genetic diversity of approximately 30 common gut commensals in five regions along the gut lumen in germ-free mice colonized with the same healthy human stool sample. While species membership and abundances varied considerably along the gut, genetic diversity within species was substantially more uniform. Driving this uniformity were similar strain frequencies along the gut, implying that multiple, genetically divergent strains of the same species can coexist within a host without spatially segregating. Additionally, the approximately 60 unique evolutionary adaptations arising within mice tended to sweep throughout the gut, showing little specificity for particular gut regions. Together, our findings show that genetic diversity may be more uniform along the gut than species diversity, which implies that species presence-absence may play a larger role than genetic variation in responding to varied environments along the gut.

Tremella aurantialba polysaccharides alleviate ulcerative colitis in mice by improving intestinal barrier via modulating gut microbiota and inhibiting ferroptosis

We aimed to investigate the effect of a polysaccharide from Tremella aurantialba on ulcerative colitis (UC), which targets ferroptosis in epithelial cells. TA 2-1 (127 kDa) was isolated from T. aurantialba and consisted of Man, Xyl, GlcA, Glc, Fuc and Rha with a molar ratio of 59.2: 23.2: 13.9: 1.6: 1.7: 0.4, exhibited a 1, 3-Man structure with branch chains of T-Xylp, 1,3-Xylp, 1,4-GlcAp, and T-Manp at its O-2 position. TA 2-1 (100 μg/mL) inhibited the cell viability of ferroptosis (19.8 %) in RLS3-induced Caco-2 cells and significantly ameliorated symptoms in the colons of mice with dextran sodium sulfate (DSS)-induced UC. TA 2-1 remarkably repaired the intestinal barrier by upregulating claudin-1 and zonula occludens-1 levels. Further analysis found TA 2-1 significantly suppressed lipid peroxidation by regulating ferroptosis-related proteins in UC mice, suggesting that its protective effects are partially mediated by inhibiting ferroptosis. Further analysis of the gut microbiota and fecal microbiota transplantation revealed TA 2-1 might relieve UC symptoms or inhibit ferroptosis by modulating the gut microbiota's composition or metabolites. Results suggest the protective effects of TA 2-1 on the intestinal barrier by inhibiting ferroptosis of epithelial cells, at least by regulating the gut microbiota, highlighting the potential of TA 2-1 in UC treatment.

The Potential Role of Plant Polysaccharides in Treatment of Ulcerative Colitis

Ulcerative colitis (UC) results in inflammation and ulceration of the colon and the rectum's inner lining. The application of herbal therapy in UC is increasing worldwide. As natural macromolecular compounds, polysaccharides have a significant role in the treatment of UC due to advantages of better biodegradation, good biocompatibility, immunomodulatory activity, and low reactogenicity. Therefore, polysaccharide drug formulation is becoming a potential candidate for UC treatment. In this review, we summarize the etiology and pathogenesis of UC and the therapeutic effects of polysaccharides on UC, such as regulating the expression of cytokines and tight junction proteins and modulating the balance of immune cells and intestinal microbiota. Polysaccharides can also serve as drug delivery carriers to enhance drug targeting and reduce side effects. This review provides a theoretical basis for applying natural plant polysaccharides in the prevention and treatment of UC.

The interplay between alterations in esophageal microbiota associated with Th17 immune response and impaired LC20 phosphorylation in achalasia

BACKGROUND

Achalasia is an esophageal motility disorder with an unknown etiology. We aimed to determine the pathogenesis of achalasia by studying alterations in esophageal smooth muscle contraction and the associated inflammatory response, and evaluate the role of esophageal microbiota in achalasia development.

METHODS

We analyzed esophageal mucosa and lower esophageal sphincter (LES) samples, obtained from patients with type II achalasia who underwent peroral endoscopic myotomy. Esophageal conditioned media obtained from patients were transferred into the mouse esophagus to determine whether the esophageal intraluminal environment is associated with achalasia.

RESULTS

Approximately 30% of 20-kDa myosin light chains (LC20) was phosphorylated in LES from the control group under resting and stimulated conditions, whereas less than 10% of LC20 phosphorylation was detected in achalasia under all conditions. The hypophosphorylation of LC20 in achalasia was associated with the downregulation of the myosin phosphatase-inhibitor protein CPI-17. Th17-related cytokines, including IL-17A, IL-17F, IL-22, and IL-23A, were significantly upregulated in achalasia. α-Diversity index of esophageal microbiota and the proportion of several microbes, including Actinomyces and Dialister, increased in achalasia. Actinomyces levels positively correlated with IL-23A levels, whereas Dialister levels were positively associated with IL-17A, IL-17F, and IL-22 levels. Esophageal IL-17F levels increased in mice after oral administration of the conditioned media.

CONCLUSIONS

In LES of patients with achalasia, hypophosphorylation of LC20, a possible cause of impaired contractility, was associated with CPI-17 downregulation and an increased Th17-related immune response. The esophageal intraluminal environment, represented by the esophageal microbiota, could be associated with the development and exacerbation of achalasia.

Intestinal Epithelial Axin1 Deficiency Protects Against Colitis via Altered Gut Microbiota

Intestinal homeostasis is maintained by specialized host cells and the gut microbiota. Wnt/β-catenin signaling is essential for gastrointestinal development and homeostasis, and its dysregulation has been implicated in inflammation and colorectal cancer. Axin1 negatively regulates activated Wnt/β-catenin signaling, but little is known regarding its role in regulating host-microbial interactions in health and disease. Here, we aim to demonstrate that intestinal Axin1 determines gut homeostasis and host response to inflammation. Axin1 expression was analyzed in human inflammatory bowel disease datasets. To explore the effects and mechanism of intestinal Axin1 in regulating intestinal homeostasis and colitis, we generated new mouse models with Axin1 conditional knockout in intestinal epithelial cell (IEC; Axin1 ΔIEC) and Paneth cell (PC; Axin1 ΔPC) to compare with control (Axin1 LoxP; LoxP: locus of X-over, P1) mice. We found increased Axin1 expression in the colonic epithelium of human inflammatory bowel disease (IBD). Axin1 ΔIEC mice exhibited altered goblet cell spatial distribution, PC morphology, reduced lysozyme expression, and enriched Akkermansia muciniphila (A. muciniphila). The absence of intestinal epithelial and PC Axin1 decreased susceptibility to dextran sulfate sodium (DSS)-induced colitis in vivo. Axin1 ΔIEC and Axin1 ΔPC mice became more susceptible to DSS-colitis after cohousing with control mice. Treatment with A. muciniphila reduced DSS-colitis severity. Antibiotic treatment did not change the IEC proliferation in the Axin1 Loxp mice. However, the intestinal proliferative cells in Axin1 ΔIEC mice with antibiotic treatment were reduced compared with those in Axin1 ΔIEC mice without treatment. These data suggest non-colitogenic effects driven by the gut microbiome. In conclusion, we found that the loss of intestinal Axin1 protects against colitis, likely driven by epithelial Axin1 and Axin1-associated A. muciniphila. Our study demonstrates a novel role of Axin1 in mediating intestinal homeostasis and the microbiota. Further mechanistic studies using specific Axin1 mutations elucidating how Axin1 modulates the microbiome and host inflammatory response will provide new therapeutic strategies for human IBD.

Constituents of stable commensal microbiota imply diverse colonic epithelial cell reactivity in patients with ulcerative colitis

BACKGROUND

Despite extensive research on microbiome alterations in ulcerative colitis (UC), the role of the constituent stable microbiota remains unclear.

RESULTS

This study, employing 16S rRNA-gene sequencing, uncovers a persistent microbial imbalance in both active and quiescent UC patients compared to healthy controls. Using co-occurrence and differential abundance analysis, the study highlights microbial constituents, featuring Phocaeicola, Collinsella, Roseburia, Holdemanella, and Bacteroides, that are not affected during the course of UC. Co-cultivation experiments, utilizing commensal Escherichia coli and Phocaeicola vulgatus, were conducted with intestinal epithelial organoids derived from active UC patients and controls. These experiments reveal a tendency for a differential response in tight junction formation and maintenance in colonic epithelial cells, without inducing pathogen recognition and stress responses, offering further insights into the roles of these microorganisms in UC pathogenesis. These experiments also uncover high variation in patients' response to the same bacteria, which indicate the need for more comprehensive, stratified analyses with an expanded sample size.

CONCLUSION

This study reveals that a substantial part of the gut microbiota remains stable throughout progression of UC. Functional experiments suggest that members of core microbiota - Escherichia coli and Phocaeicola vulgatus - potentially differentially regulate the expression of tight junction gene in the colonic epithelium of UC patients and healthy individuals.

Microbial butyrate capacity is reduced in inflamed mucosa in patients with ulcerative colitis

Reduced butyrate-production capacity has been reported in fecal microbial communities in patients with active ulcerative colitis. However, the butyrate-production capacity of the mucosal microbiome from active vs quiescent mucosa in ulcerative colitis has been unexplored. We sought to determine the diversity and relative abundance of mucosal bacterial and fungal communities from endoscopically active vs quiescent mucosa in patients with UC, and aimed to predict contributions of mucosal microbial communities to butyrate synthesis. Systematic, segmental right- and left-sided biopsies were obtained from endoscopically active (n = 13) or quiescent (n = 17) colonic mucosa, among 15 patients with pan-colonic ulcerative colitis. Dietary fiber intake of patients was performed using the validated five-item FiberScreen questionnaire. Amplicon sequencing of mucosal bacteria and fungi was performed. The diversity and relative abundance of mucosal bacterial and fungal taxa were quantified, and predicted contributions to butyrate synthesis were ascertained. Bacterial alpha and beta diversity were similar between active vs quiescent mucosa. Butyrogenic taxa were significantly increased in quiescence, including Butyricimonas, Subdoligranulum, and Alistipes. Predicted butyrate kinase activity was significantly and concomitantly increased in quiescent mucosa. Fiber intake was positively correlated with butyrogenic microbes. Compared to mucosal bacterial prevalence, mucosal fungi were detected in low prevalence. Butyrogenic microbes are relatively increased in quiescent mucosa in ulcerative colitis, and may be related to increased fiber intake during quiescence. Manipulation of the mucosal microbiome towards butyrate-producing bacteria may be associated with endoscopic quiescence.

Traditional Chinese Medicine: A promising strategy to regulate the imbalance of bacterial flora, impaired intestinal barrier and immune function attributed to ulcerative colitis through intestinal microecology

ETHNOPHARMACOLOGICAL RELEVANCE

Globally, plant materials are widely used as an additional and alternative therapy for the treating of diverse diseases. Ulcerative colitis (UC) is a chronic, recurrent and nonspecific inflammation of the bowel, referred to as "modern intractable disease" according to the World Health Organization. With the continuous development of theoretical research in Traditional Chinese Medicine (TCM) and the advantages of TCM in terms of low side effects, TCM has shown great progress in the research of treating UC.

AIM OF THIS REVIEW

This review aimed to explore the correlation between intestinal microbiota and UC, summarize research advances in TCM for treating UC, and discuss the mechanism of action of TCM remedies in regulating intestinal microbiota and repairing damaged intestinal barrier, which will provide a theoretical basis for future studies to elucidate the mechanism of TCM remedies based on gut microbiota and provide novel ideas for the clinical treatment of UC.

METHODS

We have collected and collated relevant articles from different scientific databases in recent years on the use of TCM in treating UC in relation to intestinal microecology. Based on the available studies, the therapeutic effects of TCM are analysed and the correlation between the pathogenesis of UC and intestinal microecology is explored.

RESULTS

TCM is used to further protect the intestinal epithelium and tight junctions, regulate immunity and intestinal flora by regulating intestinal microecology, thereby achieving the effect of treating UC. Additionally, TCM remedies can effectively increase the abundance of beneficial bacteria that produce short-chain fatty acids, decrease the abundance of pathogenic bacteria, restore the balance of intestinal microbiota, and indirectly alleviate intestinal mucosal immune barrier dysfunction and promote the repair of damaged colorectal mucosa.

CONCLUSION

Intestinal microbiota is closely related to UC pathogenesis. The alleviation of intestinal dysbiosis can be a potential novel therapeutic strategy for UC. TCM remedies can exert protective and therapeutic effects on UC through various mechanisms. Although intestinal microbiota can aid in the identification of different TCM syndromes types, further studies are needed using modern medical technology. This will improve the clinical therapeutic efficacy of TCM remedies in UC and promote the application of precision medicine.

Impact of gut Microbiome alteration in Ulcerative Colitis patients on disease severity and outcome

BACKGROUND

Ulcerative colitis is a heterogeneous disease in terms of disease course, location, and therapeutic response. The current study was done to assess the alteration of the gut microbiome in UC patients and its relationship to severity, response to therapy, and outcome.

PATIENTS AND METHODS

The study included 96 participants who were divided into a case group (n = 48, recent onset, treatment naive ulcerative colitis patients who were subdivided into mild, moderate, and severe subgroups based on Truelove-Witts and endoscopic severity) and a healthy control group (n = 48). All were subjected to a thorough history, clinical examination, colonoscopy, routine laboratory tests, and quantitative real-time PCR to quantify Bacteroides, Lactobacilli, Faecalibacterium prausnitzii, Veillonella, and Hemophilus in fecal samples at baseline and 6 months after treatment.

RESULTS

Bacterial 16S rRNA gene sequencing revealed a significant reduction in the phylum Firmicutes in UC patients, with a significant predominance of the phylum Bacteriodetes. F. prausnitzii and lactobacilli were inversely proportional to disease severity, whereas Bacteroides, Hemophilus, and Veillonella were directly proportional to it. Six months after therapy, a statistically significant increase in F. prausnitzii and lactobacilli was observed, with a decrease in the levels of other bacteria. Lower baseline F. praustinizii (< 8.5) increased the risk of relapse; however, lower ESR (< 10), lower post-treatment CRP (< 6), lower Bacteroides (< 10.6) indefinitely protect against relapse.

CONCLUSION

The gut microbiome of recently diagnosed UC showed lower levels of Lactobacilli, Faecalibacterium, and higher levels of Bacteroides and Veillonella, and the change in their levels can be used to predict response to therapy.

Emerging roles of host and microbial bioactive lipids in inflammatory bowel diseases

The intestinal tract harbors diverse microorganisms, host- and microbiota-derived metabolites, and potentially harmful dietary antigens. The epithelial barrier separates the mucosa, where diverse immune cells exist, from the lumen to avoid excessive immune reactions against microbes and dietary antigens. Inflammatory bowel disease (IBD), such as ulcerative colitis and Crohn's disease, is characterized by a chronic and relapsing disorder of the gastrointestinal tract. Although the precise etiology of IBD is still largely unknown, accumulating evidence suggests that IBD is multifactorial, involving host genetics and microbiota. Alterations in the metabolomic profiles and microbial community are features of IBD. Advances in mass spectrometry-based lipidomic technologies enable the identification of changes in the composition of intestinal lipid species in IBD. Because lipids have a wide range of functions, including signal transduction and cell membrane formation, the dysregulation of lipid metabolism drastically affects the physiology of the host and microorganisms. Therefore, a better understanding of the intimate interactions of intestinal lipids with host cells that are implicated in the pathogenesis of intestinal inflammation might aid in the identification of novel biomarkers and therapeutic targets for IBD. This review summarizes the current knowledge on the mechanisms by which host and microbial lipids control and maintain intestinal health and diseases.

Metabarcoding of colonic cleansing fluid reveals unique bacterial members of mucosal microbiota associated with Inflammatory Bowel Disease

BACKGROUND

Inflammatory Bowel Disease (IBD) is a group of chronic idiopathic inflammatory diseases of the gastrointestinal (GI) tract associated with the dysbiosis of gut microbiota. Metabarcoding-based profiling of the gut microbiota of IBD patients is generally based on the stool samples collected from individual patients which rarely represent the mucosa-associated microbiota. The ideal sampling strategy for routine monitoring of the mucosal component of IBD has yet to be determined.

METHODS

We hereby compare the microbiota composition of the colonic cleansing fluid (CCF) collected during colonoscopy with stool samples from IBD patients. The relationship between IBD and gut microbiota was revealed through the application of the 16S rRNA amplicon sequencing-based metabarcoding approach. CCF and stool samples were collected from IBD patients with Crohn's disease and ulcerative colitis.

RESULTS

The present study shows significant differences in the microbial composition of CCF samples, presumably indicating changes in the mucosal microbiota of IBD patients as compared to the control group. Short-chain fatty acid-producing bacteria under the family Lachnospiraceae, the actinobacterial genus Bifidobacterium, the proteobacterial Sutterella and Raoultella are found to contribute to the microbial dysbiosis of the mucosal flora in IBD patients.

CONCLUSIONS

CCF microbiota has the capacity to distinguish IBD patients from healthy controls and, thus, may constitute an alternative analysis strategy for the early diagnosis and disease progression in IBD biomarker research.

Safety and Efficacy of Fecal Microbiota Transplantation in Treatment of Inflammatory Bowel Disease in the Pediatric Population: A Systematic Review and Meta-Analysis

Background and Aims: Fecal microbiota transplantation (FMT) has been increasingly studied in the inflammatory bowel disease (IBD) population. However, most studies have focused on the adult population, and the safety and efficacy of FMT in a pediatric population is less well understood. This systematic review and meta-analysis investigates the safety and efficacy of FMT in a pediatric IBD population. Methods: A comprehensive literature search of publications published prior to 30 June 2022 was undertaken. Safety data, IBD-related outcomes, and microbiome analysis were obtained from these studies when accessible. Individual estimates of each study were pooled, and sensitivity analysis was conducted. Results: Eleven studies satisfied our eligibility criteria. The calculated pooled rate of adverse events was 29% (95% confidence interval [CI]: 15.0%, 44.0%; p < 0.001; I2 = 89.0%, Q = 94.53), and the calculated pooled rate of serious adverse events was 10% (95% confidence interval [CI]: 6.0%, 14.0%; p = 0.28; I2 = 18.0%, Q = 9.79). One month after FMT, clinical response was achieved in 20/34 (58.8%) pediatric IBD patients, clinical remission was achieved in 22/34 (64.7%), and both clinical response and remission were achieved in 15/34 (44.1%) pediatric IBD patients. Conclusions: FMT can be a safe and effective treatment in the pediatric IBD population and may demonstrate improved safety and efficacy in the pediatric population compared to the adult population. However, our results are limited by a lack of established protocol as well as long-term follow-up for FMT in a pediatric IBD population.

Synbiotic-IgY Therapy Modulates the Mucosal Microbiome and Inflammatory Indices in Dogs with Chronic Inflammatory Enteropathy: A Randomized, Double-Blind, Placebo-Controlled Study

Chronic inflammatory enteropathy (CE) is a common cause of persistent gastrointestinal signs and intestinal inflammation in dogs. Since evidence links dysbiosis to mucosal inflammation, probiotics, prebiotics, or their combination (synbiotics) may reduce intestinal inflammation and ameliorate dysbiosis in affected dogs. This study's aim was to investigate the effects of the synbiotic-IgY supplement on clinical signs, inflammatory indices, and mucosal microbiota in dogs with CE. Dogs with CE were enrolled in a randomized prospective trial. Twenty-four client-owned dogs were fed a hydrolyzed diet and administered supplement or placebo (diet) for 6 weeks. Dogs were evaluated at diagnosis and 2- and 6-week post-treatment. Outcome measures included clinical activity, endoscopic and histologic scores, inflammatory markers (fecal calprotectin, C-reactive protein), and composition of the mucosal microbiota via FISH. Eleven supplement- and nine placebo-treated dogs completed the trial. After 6 weeks of therapy, clinical activity and endoscopic scores decreased in both groups. Compared to placebo-treated dogs, dogs administered supplement showed decreased calprotectin at 2-week post-treatment, decreased CRP at 2- and 6-week post-treatment increased mucosal Clostridia and Bacteroides and decreased Enterobacteriaceae in colonic biopsies at trial completion. Results suggest a beneficial effect of diet and supplements on host responses and mucosal microbiota in dogs with CE.

Efficacy and Safety of Bifidobacterium Quadruple Viable Bacteria Combined with Mesalamine against UC Management: A Systematic Review and Meta-Analysis

Objective

To systematically assess effectiveness and safety of Bifidobacterium quadruple viable bacteria combined with mesalamine against ulcerative colitis (UC) in the Asian population.

Methods

An electronic search was conducted in PubMed, Embase, Cochrane Library, CNKI, VIP, and Wanfang databases for a random collection of controlled trials of Bifidobacterium quadruple viable bacteria combined with mesalamine against UC. Following data screening and extraction, a Cochrane risk assessment tool was adopted to evaluate the quality of the included studies, and RevMan 5.3 and Stata/SE 15.1 software were used for meta-analysis.

Results

Nineteen articles which enrolled 1,707 subjects were included ultimately in this study. The experimental group performed better than the control group in improving the Mayo score (MD = -1.94, 95% CI = (-2.69, -1.19), P < 0.00001), increasing the total clinical efficiency (OR = 5.10, 95% CI (3.53, 7.38), P < 0.00001), reducing the levels of IL-8 (SMD = -1.79, 95% CI (-2.36, -1.12), P < 0.00001), increasing the levels of IL-4 (SMD = 1.00, 95% CI (0.60, 1.41), P < 0.00001), and reducing the levels of hsCRP (MD = -3.26, 95% CI (-4.28, -2.25), P < 0.00001), TNF-α (MD = -7.11, 95% CI (-9.23, -5.00), P < 0.00001), ox-LDL (MD = -14.46, 95% CI (-17.20, -11.72), P < 0.00001), and LPO (MD = -3.55, 95% CI (-4.70, -2.39), P < 0.0001) as well as increasing SOD level (SMD = 1.68, 95% CI (1.02, 2.35), P < 0.00001), and adverse reactions were substantially less than that of control (OR = 0.43, 95% CI = (0.28, 0.66), P = 0.0001).

Conclusion

In conclusion, the current meta-analysis shows that Bifidobacterium quadruple viable bacterium combined with mesalamine has a satisfactory effect in the treatment of UC in China, and its safety is better than that of mesalamine or Bifidobacterium quadruple viable bacteria alone. However, randomized controlled trials with standardized designs and large sample sizes are still needed for further validation.

Probiotic-Based Intervention in the Treatment of Ulcerative Colitis: Conventional and New Approaches

Although there are number of available therapies for ulcerative colitis (UC), many patients are unresponsive to these treatments or experience secondary failure during treatment. Thus, the development of new therapies or alternative strategies with minimal side effects is inevitable. Strategies targeting dysbiosis of gut microbiota have been tested in the management of UC due to the unquestionable role of gut microbiota in the etiology of UC. Advanced molecular analyses of gut microbiomes revealed evident dysbiosis in UC patients, characterized by a reduced biodiversity of commensal microbiota. Administration of conventional probiotic strains is a commonly applied approach in the management of the disease to modify the gut microbiome, improve intestinal barrier integrity and function, and maintain a balanced immune response. However, conventional probiotics do not always provide the expected health benefits to a patient. Their benefits vary significantly, depending on the type and stage of the disease and the strain and dose of the probiotics administered. Their mechanism of action is also strain-dependent. Recently, new candidates for potential next-generation probiotics have been discovered. This could bring to light new approaches in the restoration of microbiome homeostasis and in UC treatment in a targeted manner. The aim of this paper is to provide an updated review on the current options of probiotic-based therapies, highlight the effective conventional probiotic strains, and outline the future possibilities of next-generation probiotic and postbiotic supplementation and fecal microbiota transplantation in the management of UC.

Outcomes of Inflammatory Bowel Disease in Hospitalized Patients With Generalized Anxiety Disorder

Background

The development of inflammatory bowel disease (IBD), which encompasses ulcerative colitis and Crohn’s disease, is multifactorial. Stress from anxiety is a risk factor for IBD. Generalized anxiety disorder (GAD) is twice as likely in IBD patients. This study explores the outcomes of patients hospitalized for IBD with comorbid GAD.

Methods

A retrospective analysis utilizing the 2014 USA National Inpatient Sample database was performed to assess the outcomes of hospitalized IBD patients with and without GAD. The outcomes analyzed were sepsis, acute hepatic failure, hypotension/shock, acute respiratory failure, acute deep vein thrombosis, acute renal failure, intestinal obstruction, myocardial infarction, ileus, inpatient mortality, colectomy, intestinal abscess, intestinal perforation, and megacolon. A multivariate logistic regression analysis was employed to explore whether GAD is a risk factor for these outcomes.

Results

Among 28,173 IBD hospitalized patients in the study, GAD was a comorbid diagnosis in 3,400 of those patients. IBD patients with coexisting GAD were found to be at increased risk for acute hepatic failure (adjusted odds ratio (aOR) 1.80, p = 0.006), sepsis (aOR 1.33, p < 0.001), acute respiratory failure (aOR 1.24, p = 0.018), inpatient mortality (aOR 1.87, p < 0.001), intestinal abscess (aOR 2.35, p = 0.013), and intestinal perforation (aOR 1.44, p = 0.019). The aORs for the remaining outcomes were not statistically significant.

Conclusions

In hospitalized IBD patients, GAD is a risk factor for sepsis, acute hepatic failure, acute respiratory failure, intestinal abscess, intestinal perforation, and inpatient mortality. IBD and GAD are becoming increasingly common, which will likely lead to a larger number of complications among inpatients with these comorbidities.

Prevotella: An insight into its characteristics and associated virulence factors

Prevotella species, a gram-negative obligate anaerobe, is commonly associated with human infections such as dental caries and periodontitis, as well as other conditions such as chronic osteomyelitis, bite-related infections, rheumatoid arthritis and intestinal diseases like ulcerative colitis. This generally harmless commensal possesses virulence factors such as adhesins, hemolysins, secretion systems exopolysaccharide, LPS, proteases, quorum sensing molecules and antibiotic resistance to evolve into a well-adapted pathogen capable of causing successful infection and proliferation in the host tissue. This review describes several of these virulence factors and their advantage to Prevotella spp. in causing inflammatory diseases like periodontitis. In addition, using genome analysis of Prevotella reference strains, we examined other putative virulence determinants which can provide insights as biomarkers and be the targets for effective interventions in Prevotella related diseases like periodontitis.

Zingiber officinale and Panax ginseng ameliorate ulcerative colitis in mice via modulating gut microbiota and its metabolites

Zingiber officinale and Panax ginseng, as well-known traditional Chinese medicines, have been used together to clinically treat ulcerative colitis with synergistic effects for thousands of years. However, their compatibility mechanism remains unclear. In this study, the shift of gut microbiome and fecal metabolic profiles were monitored by 16S rRNA sequencing technology and ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry analysis, respectively, which aimed to reveal the synergistic mechanism of Zingiber officinale and Panax ginseng on the amelioration of ulcerative colitis. The results showed that the relative abundance of beneficial bacteria (such as Muribaculaceae_norank, Lachnospiraceae NK4A136 group and Akkermansia) was significantly increased and the abundance of pathogenic bacteria (such as Bacteroides, Parabacteroides and Desulfovibrio) was markedly decreased after the intervention of Zingiber officinale-Panax ginseng herb pair. And a total of 16 differential metabolites related to ulcerative colitis were identified by the metabolomics analysis, which were majorly associated with the metabolic pathways, including arachidonic acid metabolism, tryptophan metabolism, and steroid biosynthesis. Based on these findings, it was suggested that the regulation of the gut microbiota-metabolite axis might be a potential target for the synergistic mechanism of Zingiber officinale-Panax ginseng herb pair in the treatment of ulcerative colitis. Furthermore, the integrated analysis of microbiome and metabolomics used in this study could also serve as a useful template for exploring the mechanism of other drugs.

Intestinal Microbiota - An Unmissable Bridge to Severe Acute Pancreatitis-Associated Acute Lung Injury

Severe acute pancreatitis (SAP), one of the most serious abdominal emergencies in general surgery, is characterized by acute and rapid onset as well as high mortality, which often leads to multiple organ failure (MOF). Acute lung injury (ALI), the earliest accompanied organ dysfunction, is the most common cause of death in patients following the SAP onset. The exact pathogenesis of ALI during SAP, however, remains unclear. In recent years, advances in the microbiota-gut-lung axis have led to a better understanding of SAP-associated lung injury (PALI). In addition, the bidirectional communications between intestinal microbes and the lung are becoming more apparent. This paper aims to review the mechanisms of an imbalanced intestinal microbiota contributing to the development of PALI, which is mediated by the disruption of physical, chemical, and immune barriers in the intestine, promotes bacterial translocation, and results in the activation of abnormal immune responses in severe pancreatitis. The pathogen-associated molecular patterns (PAMPs) mediated immunol mechanisms in the occurrence of PALI via binding with pattern recognition receptors (PRRs) through the microbiota-gut-lung axis are focused in this study. Moreover, the potential therapeutic strategies for alleviating PALI by regulating the composition or the function of the intestinal microbiota are discussed in this review. The aim of this study is to provide new ideas and therapeutic tools for PALI patients.

Gut Microbiota Associated with Clinical Relapse in Patients with Quiescent Ulcerative Colitis

The microbiota associated with relapse in patients with quiescent ulcerative colitis (qUC) remains unclear. Our objective was to analyze the fecal microbiota of Japanese patients with qUC and identify the relapse-associated microbiota. In this study, 59 patients with qUC and 59 healthy controls (HCs) were enrolled (UMIN 000019486), and their fecal microbiota was compared using 16S rRNA gene amplicon sequencing. We followed their clinical course up to 3.5 years and analyzed the relapse-associated microbiota. Potential functional changes in the fecal microbiota were evaluated using PICRUSt software and the Kyoto Encyclopedia of Genes and Genomes database. There were significant differences in fecal microbiota diversity between HC and qUC subjects, with 13 taxa characterizing each subject. Despite no significant difference in variation of microbiota in a single sample (α diversity) between patients in sustained remission and relapsed patients, the variation in microbial communities between samples (β diversity) was significantly different. Prevotella was more abundant in the sustained remission patients, whereas Faecalibacterium and Bifidobacterium were more abundant in the relapsed patients. We clustered the entire cohort into four clusters, and Kaplan-Meier analysis revealed the subsequent clinical course of each cluster was different. We identified 48 metabolic pathways associated with each cluster using linear discriminant analysis effect size. We confirmed the difference in microbiota between patients with qUC and HCs and identified three genera associated with relapse. We found that the clusters based on these genera had different subsequent clinical courses and activated different metabolic pathways.

Dynamic Changes in Gut Microbiome of Ulcerative Colitis: Initial Study from Animal Model

Background

An animal model of DSS-induced UC has been widely used in basic research, and the dysbiosis of gut microbiome is one of the important pathogenetic mechanisms of DSS-induced UC, but its dynamic changes and correlation with inflammatory factors are not clear yet.

Methods

Clinical signs and tissue damage degree of C57BL/6 ulcerative colitis mice model induced by different concentrations of DSS were compared with that of normal mice, and finally the optimal concentration of DSS was determined. Then we analyzed the sequencing results of gut microbiome and inflammatory factors to determine the dynamic patterns of gut microbiome and their correlation with the inflammatory factors.

Results

DSS at 2.5% and 3.0% concentration could cause intestinal injury and induce colitis. However, 3.0% DSS resulted in higher mortality. In addition, there were dynamic changes of gut microbiome in DSS-induced UC model: the relative abundance of intestinal flora increased first and then decreased in Bacteroides, Parabacteroides, Romboutsia, Clostridium_sensu_stricto_1, Lachnospiraceae_NK4A136_group, norank_f_norank_o_Clostridia_UCG-014, Parasutterella, and decreased first and then increased in Lactobacillus, Muribaculum, norank_f_Muribaculaceae, in addition, Bifidobacterium, Coriobacteriaceae_UCG-002 and Enterorhabdus did not change in the first 14 days but increased significantly on day 21. Moreover, inflammatory cytokines were closely associated with the imbalance of the intestinal microbiota in mice with UC: most pathogenic bacteria in the intestinal tract of the UC animal model were positively correlated with pro-inflammatory factors and negatively correlated with anti-inflammatory factors, while beneficial bacteria were the opposite.

Conclusion

Intestinal microecology plays an important role in DSS-induced UC model, and the relative abundance of gut microbiome changes dynamically in the occurrence and development of ulcerative colitis.

Bifidobacterium infantis Maintains Genome Stability in Ulcerative Colitis via Regulating Anaphase-Promoting Complex Subunit 7

Probiotics represents a promising intestinal microbiota-targeted therapeutic method for the treatment of ulcerative colitis (UC). Several lines of evidence implicate that Bifidobacterium infantis serves as a probiotic strain with proven efficacy in maintaining the remission of UC. However, the exact mechanisms underlying the beneficial effects of B. infantis on UC progression have yet to be elucidated. Herein, we provide evidence that B. infantis acts as a key predisposing factor for the maintenance of host genome stability. First, we showed that the fecal microbiota transplantation (FMT) of UC-derived feces contributes to more severely DNA damage in dextran sodium sulfate (DSS)-induced mice likely due to mucosa-associated microbiota alterations, as reflected by the rapid appearance of DNA double strand breaks (DSBs), a typical marker of genome instability. Genomic DNA damage analysis of colon tissues derived from healthy controls, patients with UC or dysplasia, and colitis associated cancer (CAC) patients, revealed an enhanced level of DSBs with aggravation in the degree of the intestinal mucosal lesions. To evaluate whether B. infantis modulates the host genome stability, we employed the DSS-induced colitis model and a TNFα-induced intestinal epithelial cell model. Following the administration of C57BL/6 mice with B. infantis via oral gavage, we found that the development of DSS-induced colitis in mice was significantly alleviated, in contrast to the colitis model group. Notably, B. infantis administration decreased DSB levels in both DSS-induced colitis and TNF-treated colonial cell model. Accordingly, our bioinformatic and functional studies demonstrated that B. infantis altered signal pathways involved in ubiquitin-mediated proteolysis, transcriptional misregulation in cancer, and the bacterial invasion of epithelial cells. Mechanistically, B. infantis upregulated anaphase-promoting complex subunit 7 (APC7), which was significantly suppressed in colitis condition, to activate the DNA repair pathway and alter the genome stability, while downregulation of APC7 abolished the efficiency of B. infantis treatment to induce a decrease in the level of DSBs in TNFα-induced colonial cells. Collectively, our results support that B. infantis orchestrates a molecular network involving in APC7 and genome stability, to control UC development at the clinical, biological, and mechanistic levels. Supplying B. infantis and targeting its associated pathway will yield valuable insight into the clinical management of UC patients.

Microbiota-Immune Interactions in Ulcerative Colitis and Colitis Associated Cancer and Emerging Microbiota-Based Therapies

Ulcerative colitis (UC) is a chronic autoimmune disorder affecting the colonic mucosa. UC is a subtype of inflammatory bowel disease along with Crohn's disease and presents with varying extraintestinal manifestations. No single etiology for UC has been found, but a combination of genetic and environmental factors is suspected. Research has focused on the role of intestinal dysbiosis in the pathogenesis of UC, including the effects of dysbiosis on the integrity of the colonic mucosal barrier, priming and regulation of the host immune system, chronic inflammation, and progression to tumorigenesis. Characterization of key microbial taxa and their implications in the pathogenesis of UC and colitis-associated cancer (CAC) may present opportunities for modulating intestinal inflammation through microbial-targeted therapies. In this review, we discuss the microbiota-immune crosstalk in UC and CAC, as well as the evolution of microbiota-based therapies.