Systematic Review and Meta-analysis: Fecal Microbiota Transplantation for Treatment of Active Ulcerative Colitis

Insect meal in aquafeeds: A sustainable path to enhanced mucosal immunity in fish

The mucosal surfaces of fish, including their intestines, gills, and skin, are constantly exposed to various environmental threats, such as water quality fluctuations, pollutants, and pathogens. However, various cells and microbiota closely associated with these surfaces work in tandem to create a functional protective barrier against these conditions. Recent research has shown that incorporating specific feed ingredients into fish diets can significantly boost their mucosal and general immune response. Among the various ingredients being investigated, insect meal has emerged as one of the most promising options, owing to its high protein content and immunomodulatory properties. By positively influencing the structure and function of mucosal surfaces, insect meal (IM) has the potential to enhance the overall immune status of fish. This review provides a comprehensive overview of the potential benefits of incorporating IM into aquafeed as a feed ingredient for augmenting the mucosal immune response of fish.

Comparison of the use of a spiral nasojejunal tube and transendoscopic enteral tubing in washed microbiota transplantation via the mid-gut route

Background

Methods for washed microbiota transplantation (WMT) through the mid-gut include transendoscopic enteral tubing (TET) and manual spiral nasojejunal tube (SNT) placement have not been studied.

Methods

This prospective interventional study was performed at a single centre. Patients were divided into the SNT and mid-gut TET groups based on their conditions and wishes. In the SNT group, an SNT was passively inserted into the stomach, and abdominal X-rays were taken within 24 h to confirm tube placement in the small intestine. In the mid-gut TET group, mid-gut TET was placed in the small intestine for gastroscopy. Data on the clinical efficacy of WMT, intubation time, cost, overall comfort score, adverse reactions, etc., were collected from the two groups.

Results

Sixty-three patients were included in the study (SNT group (n = 40) and mid-gut TET group (n = 23)). The clinical efficacy of WMT in the SNT and mid-gut TET groups was 90 % and 95.7 %, respectively (P = 0.644). Compared with the mid-gut TET group, the SNT group showed a shorter operation time (120 s vs. 258 s, P = 0.001) and a lower average cost (641.7 yuan vs. 1702.1 yuan, P = 0.001). There was no significant difference in the overall comfort score or the incidence of common discomfort symptoms between the two groups.

Conclusion

The different implantation methods have different advantages; compared with mid-gut TET placement, manual SNT placement provides some benefits.

Categorization of the effects of E. coli LF82 and mutants lacking the chuT and shuU genes on survival, the transcriptome, and metabolome in germ-free honeybee

The precise etiology of inflammatory bowel diseases (IBDs) remains elusive. The Escherichia coli strain LF82 (LF82) is known to be associated with IBD, and we hypothesized that this association may be related to the chuT and shuU genes. Here we constructed a germ-free (GF) honeybee model to investigate the effects of LF82 chuT and shuU genes on the honeybee intestine and their mechanisms. The chuT and shuU gene deletion strains LF82∆chuT and LF82∆shuU were generated by CRISPR-Cas9. These strains, together with nonpathogenic E. coli MG1655 (MG1655) and wildtype LF82, were allowed to colonize the guts of GF honeybees to establish single bacterial colonization models. Intestinal permeability was assessed following the administration of a sterile Brilliant Blue (FCF) solution. Comprehensive transcriptomic and metabolomic analyses of intestinal samples indicated that MG1655 had few disadvantageous effects on honeybees. Conversely, colonization with LF82 and its gene-deletion mutants provoked pronounced activation of genes associated with innate immune pathways, stimulated defensive responses, and induced expression of genes associated with inflammation, oxidative stress, and glycosaminoglycan degradation. Crucially, the LF82∆chuT and LF82∆shuU strains perturbed host heme and iron regulation, as well as tryptophan metabolism. These findings suggest that the deletion of chuT and shuU genes in E. coli LF82 may alleviate intestinal inflammation by partially modulating tryptophan catabolism. Our study proposes that targeting iron uptake mechanisms could be a potential strategy to mitigate the virulence of IBD-associated bacteria.

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

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

Dynamics of the Gut Mycobiome in Patients With Ulcerative Colitis

BACKGROUND & AIMS

Intestinal fungi have been implicated in the pathogenesis of ulcerative colitis (UC). However, it remains unclear if fungal composition is altered during active versus quiescent disease.

METHODS

We analyzed clinical and metagenomic data from the Study of a Prospective Adult Research Cohort with Inflammatory Bowel Disease (SPARC IBD), available via the IBD Plexus Program of the Crohn's & Colitis Foundation. We evaluated the fungal composition of fecal samples from 421 patients with UC during clinical activity and remission. Within a longitudinal subcohort (n = 52), we assessed for dynamic taxonomic changes across alterations in clinical activity over time. We examined if fungal amplicon sequence variants and fungal-bacterial relationships were altered during activity versus remission. Finally, we classified activity in UC using a supervised machine learning random forest model trained on fungal abundance data.

RESULTS

During clinical activity, the relative abundance of genus Candida was increased 3.5-fold (P-adj < 1 × 10-4) compared with during remission. Patients with longitudinal reductions in clinical activity demonstrated parallel reductions in Candida relative abundance (P < .05). Candida relative abundance correlated with Parabacteroides diastonis, Faecalibacterium prausnitzii, and Bacteroides dorei relative abundance (P < .05) during remission; however, these correlations were disrupted during activity. Fungal abundance data successfully classified patients with active or quiescent UC (area under the curve ∼0.80), with Candida relative abundance critical to the success of the model.

CONCLUSIONS

Clinical activity in UC is associated with an increased relative abundance of Candida, cross-sectionally and dynamically over time. The role of fecal Candida as a target for therapeutics in UC should be evaluated.

From gut to brain: understanding the role of microbiota in inflammatory bowel disease

With the proposal of the "biological-psychological-social" model, clinical decision-makers and researchers have paid more attention to the bidirectional interactive effects between psychological factors and diseases. The brain-gut-microbiota axis, as an important pathway for communication between the brain and the gut, plays an important role in the occurrence and development of inflammatory bowel disease. This article reviews the mechanism by which psychological disorders mediate inflammatory bowel disease by affecting the brain-gut-microbiota axis. Research progress on inflammatory bowel disease causing "comorbidities of mind and body" through the microbiota-gut-brain axis is also described. In addition, to meet the needs of individualized treatment, this article describes some nontraditional and easily overlooked treatment strategies that have led to new ideas for "psychosomatic treatment".

Faecal Microbiota Transplantation [FMT] in the Treatment of Chronic Refractory Pouchitis: A Systematic Review and Meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis is to assess the efficacy and safety of faecal microbiota transplantation [FMT] in the treatment of chronic pouchitis.

METHODS

A PRISMA-compliant systematic review and meta-analysis was conducted using the following databases and clinical trial registers: Medline, Embase, Scopus, Cochrane Database of Systematic Reviews [CENTRAL], clinical trials.gov, ScienceDirect, and VHL [virtual health library]. The primary outcome was clinical response/remission in patients treated with FMT. Secondary outcomes included safety profile, quality of life, and changes in the gut microbiome.

RESULTS

Seven observational cohort studies/case series and two randomised, controlled trials with a total of 103 patients were included. The route, preparation, and quantity of FMT administered varied among the included studies. Clinical response rate of 42.6% with a remission rate of 29.8% was estimated in our cohort following FMT therapy. Minor, self-limiting, adverse events were reported, and the treatment was well tolerated with good short- and long-term safety profiles. Successful FMT engraftment in recipients varied and, on average, microbial richness and diversity was lower in patients with pouchitis. In some instances, shifts with specific changes towards abundance of species, suggestive of a 'healthier' pouch microbiota, were observed following treatment with FMT.

CONCLUSION

The evidence for FMT in the treatment of chronic pouchitis is sparse, which limits any recommendations being made for its use in clinical practice. Current evidence from low-quality studies suggests a variable clinical response and remission rate, but the treatment is well tolerated, with a good safety profile. This review emphasises the need for rationally designed, well-powered, randomised, placebo-controlled trials to understand the efficacy of FMT for the treatment of pouchitis.

Moxibustion improved the effect of fecal microbiota transplantation donor to dextran sulfate sodium-induced colitis in mice

Fecal microbiota transplantation (FMT) is beneficial for several gastrointestinal diseases because it alters the intestinal microbiota of recipients. The efficacy of FMT is related to the microbial structure and composition of the donor. Mild moxibustion is a non-invasive and safe traditional Chinese therapy that can regulate the gut microbiota. In this study, we investigated whether moxibustion improved the efficacy of FMT in donors using a dextran sulfate sodium (DSS)-induced colitis mouse model. Normal mice were treated with mild moxibustion at acupoints ST25 and ST36 for 7 days. DSS (2%) was administered for 7 days to induce colitis. FMT was performed on Day 8 and lasted for 7 days. The effect of FMT on mice with DSS was observed on Day 21. Using hematoxylin and eosin staining and immunofluorescence, we analyzed the pathology and cell proliferation after FMT in DSS mice. In addition, using 16 S rDNA sequencing analysis, we investigated the gut microbiota of mice. The results indicated that moxibustion altered the colonic microbial community and increased the relative abundance of specific bacteria without changes in morphology and physiological function in normal mice. FMT using donors with moxibustion reduced body weight loss, inflammation, abnormal microbial community structure, and the relative abundance of some bacteria. These results provide potential strategies for the safe and targeted improvement of FMT donors.

Role of Fecal Microbiota Transplantation in Managing Clostridium Difficile Infection and Inflammatory Bowel Disease: A Narrative Review

Fecal microbiota transplantation (FMT) has been emerging as an alternate treatment modality in the management of patients with dysbiosis by restoring abnormal gut microbiota composition through the transplantation of normal fecal microbiota from healthy donors. This technique has lately gained a lot of attention in the treatment of recurrent or refractory Clostridium difficile infection (CDI) owing to its high success rates combined with its favorable safety profile. FMT has also been attracting the interest of clinicians as a new treatment option for inflammatory bowel diseases (IBD). Here, we reviewed most of the recent advancements in the use of FMT for CDI as well as its use in the treatment of IBD.

The role of the microbiota in glaucoma

Glaucoma is a common irreversible vision loss disorder because of the gradual loss of retinal ganglion cells (RGCs) and the optic nerve axons. Major risk factors include elder age and high intraocular pressure (IOP). However, high IOP is neither necessary nor sufficient to cause glaucoma. Some non-IOP signaling cascades can mediate RGC degeneration. In addition, gender, diet, obesity, depression, or anxiety also contribute to the development of glaucoma. Understanding the mechanism of glaucoma development is crucial for timely diagnosis and establishing new strategies to improve current IOP-reducing therapies. The microbiota exerts a marked influence on the human body during homeostasis and disease. Many glaucoma patients have abnormal compositions of the microbiota (dysbiosis) in multiple locations, including the ocular surface, intraocular cavity, oral cavity, stomach, and gut. Here, we discuss findings in the last ten years or more about the microbiota and metabolite changes in animal models, patients with three risk factors (aging, obesity, and depression), and glaucoma patients. Antigenic mimicry and heat stress protein (HSP)-specific T-cell infiltration in the retina may be responsible for commensal microbes contributing to glaucomatous RGC damage. LPS-TLR4 pathway may be the primary mechanism of oral and ocular surface dysbiosis affecting glaucoma. Microbe-derived metabolites may also affect glaucoma pathogenesis. Homocysteine accumulation, inflammatory factor release, and direct dissemination may link gastric H. pylori infection and anterior chamber viral infection (such as cytomegalovirus) to glaucoma. Potential therapeutic protocols targeting microbiota include antibiotics, modified diet, and stool transplant. Later investigations will uncover the underlying molecular mechanism connecting dysbiosis to glaucoma and its clinical applications in glaucoma management.

Fecal microbiota transplantation as a therapy for treating ulcerative colitis: an overview of systematic reviews

AIM

The current overview on published systematic reviews (SRs) and meta-analysis (MAs) aimed to systematically gather, evaluate, and synthesize solid evidence for using fecal microbiota transplantation (FMT) to treat ulcerative colitis (UC).

METHODS

Relevant articles published before January 2023 were collected from Web of Science, Embase, PubMed, and Cochrane Library. Two authors used Assessment of Multiple Systematic Reviews 2 (AMSTAR-2) tool, PRISMA checklists, and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system were applied by two authors to independently evaluate the methodological quality, reporting quality, and evidence quality, respectively. Re-meta-analysis on the primary RCTs was conducted after excluding overlapping randomized controlled trials (RCTs).

RESULTS

Six SRs/MAs involving 12 primary RCTs and 544 participants were included. According to the AMSTAR-2 tool and PRISMA checklist, methodological quality and reporting quality of the included studies was overall satisfactory. The evidence quality of a great majority of outcomes was rated as moderate to high according to the GRADE system. Compared to placebo, the re-meta-analysis found a great advantage of use FMT in inducing combined clinical and endoscopic remission (OR 3.83 [2.31, 6.34]), clinical remission (3.31 [2.09, 5.25]), endoscopic remission (OR 3.75 [2.20, 6.39]), clinical response (OR 2.56 [1.64, 4.00]), and endoscopic response (OR 2.18 [1.12, 4.26]). Pooled data showed no significant difference in serious adverse events between patients receiving FMT and those receiving placebo (OR 1.53 [0.74, 3.19]). Evidence quality of the outcomes derived from re-meta-analysis was significantly higher after overcoming the limitations of previous SRs/MAs.

CONCLUSION

In conclusion, moderate- to high-quality evidence supported a promising use of FMT to safely induce remission in UC. However, further trials with larger sample size are still required to comprehensively analyze the delivery route, total dosage, frequency, and donor selection in FMT.

Safety and feasibility of faecal microbiota transplantation for patients with Parkinson's disease: a protocol for a self-controlled interventional donor-FMT pilot study

INTRODUCTION

Experimental studies suggest a role of gut microbiota in the pathophysiology of Parkinson's disease (PD) via the gut-brain axis. The gut microbiota can also influence the metabolism of levodopa, which is the mainstay of treatment of PD. Therefore, modifying the gut microbiota by faecal microbiota transplantation (FMT) could be a supportive treatment strategy.

METHODS AND ANALYSIS

We have developed a study protocol for a single-centre, prospective, self-controlled, interventional, safety and feasibility donor-FMT pilot study with randomisation and double-blinded allocation of donor faeces. The primary objectives are feasibility and safety of FMT in patients with PD. Secondary objectives include exploring whether FMT leads to alterations in motor complications (fluctuations and dyskinesias) and PD motor and non-motor symptoms (including constipation), determining alterations in gut microbiota composition, assessing donor-recipient microbiota similarities and their association with PD symptoms and motor complications, evaluating the ease of the study protocol and examining FMT-related adverse events in patients with PD. The study population will consist of 16 patients with idiopathic PD that use levodopa and experience motor complications. They will receive FMT with faeces from one of two selected healthy human donors. FMT will be administered via a gastroscope into the duodenum, after treatment with oral vancomycin, bowel lavage and domperidone. There will be seven follow-up moments during 12 months.

ETHICS AND DISSEMINATION

This study was approved by the Medical Ethical Committee Leiden Den Haag Delft (ref. P20.087). Study results will be disseminated through publication in peer-reviewed journals and international conferences.

TRIAL REGISTRATION NUMBER

International Clinical Trial Registry Platform: NL9438.

Exploring gut microbiota in adult Atlantic salmon (Salmo salar L.): Associations with gut health and dietary prebiotics

BACKGROUND

The importance of the gut microbiota for physiological processes in mammals is well established, but the knowledge of their functional roles in fish is still limited. The aims of this study were to investigate associations between variation in taxonomical composition of the gut microbiota and gut health status in Atlantic salmon and to explore possible modulatory effects of dietary prebiotics in one net-pen farm in open water. The fish with initial mean body weight of around 240 g were fed diets based on the same basal composition, either without (Ref diet) or with (Test diet) yeast cell wall based-prebiotics, during the marine production phase from December to September the following year. Sampling was conducted at three sampling time points: January, April, and September, with average water temperature of 3.9 ℃, 3.4 ℃ and 9.6 ℃, respectively.

RESULTS

As the fish progressed towards September, growth, brush border membrane enzyme activities, and the expression in the gut of most of the observed genes involved in immune (e.g., il8, cd4a, myd88, il1b, gilt, tgfb, cd8b and cd3), barrier (e.g., zo1, occludin, ecad, claudin25b and claudin15), and metabolism increased significantly. Lipid accumulation in pyloric enterocytes decreased remarkably, suggesting improvement of gut health condition. The growth of the fish did not differ between dietary treatments. Further, dietary prebiotics affected the gut health only marginally regardless of duration of administration. Regarding gut microbiota composition, a decrease in alpha diversity (Observed species, Pielou and Shannon) over time was observed, which was significantly associated with an increase in the relative abundance of genus Mycoplasma and decrease in 32 different taxa in genus level including lactic acid bacteria (LAB), such as Lactobacillus, Leuconostoc, and Lactococcus. This indicates that developmental stage of Atlantic salmon is a determinant for microbial composition. Multivariate association analysis revealed that the relative abundance of Mycoplasma was positively correlated with gut barrier gene expression, negatively correlated with plasma glucose levels, and that its relative abundance slightly increased by exposure to prebiotics. Furthermore, certain LAB (e.g., Leuconostoc), belonging to the core microbiota, showed a negative development with time, and significant associations with plasma nutrients levels (e.g., triglyceride and cholesterol) and gene expression related to gut immune and barrier function.

CONCLUSIONS

As Atlantic salmon grew older under large-scale, commercial farm settings, the Mycoplasma became more prominent with a concomitant decline in LAB. Mycoplasma abundance correlated positively with time and gut barrier genes, while LAB abundance negatively correlated to time. Dietary prebiotics affected gut health status only marginally.

The first international Rome consensus conference on gut microbiota and faecal microbiota transplantation in inflammatory bowel disease

BACKGROUND

Several randomised clinical trials (RCTs) performing faecal microbiota transplantation (FMT) for the management of inflammatory bowel disease (IBD), particularly for ulcerative colitis, have recently been published, but with major variations in study design. These include differences in administered dose, route and frequency of delivery, type of placebo and evaluated endpoints. Although the overall outcomes appear to be promising, they are highly dependent on both donor and recipient factors.

OBJECTIVE

To develop concensus-based statements and recommendations for the evaluation, management and potential treatment of IBD using FMT in order to move towards standardised practices.

DESIGN

An international panel of experts convened several times to generate evidence-based guidelines by performing a deep evaluation of currently available and/or published data. Twenty-five experts in IBD, immunology and microbiology collaborated in different working groups to provide statements on the following key issues related to FMT in IBD: (A) pathogenesis and rationale, (B) donor selection and biobanking, (C) FMT practices and (D) consideration of future studies and perspectives. Statements were evaluated and voted on by all members using an electronic Delphi process, culminating in a plenary consensus conference and generation of proposed guidelines.

RESULTS AND CONCLUSIONS

Our group has provided specific statements and recommendations, based on best available evidence, with the end goal of providing guidance and general criteria required to promote FMT as a recognised strategy for the treatment of IBD.

The role of sphingosine-1-phosphate in the gut mucosal microenvironment and inflammatory bowel diseases

Sphingosine-1-phosphate (S1P), a type of bioactive sphingolipid, can regulate various cellular functions of distinct cell types in the human body. S1P is generated intracellularly by the catalysis of sphingosine kinase 1/2 (SphK1/2). S1P is transferred to the extracellular environment via the S1P transporter, binds to cellular S1P receptors (S1PRs) and subsequently activates S1P-S1PR downstream signaling. Dysbiosis of the intestinal microbiota, immune dysregulation and damage to epithelial barriers are associated with inflammatory bowel disease (IBD). Generally, S1P mainly exerts a proinflammatory effect by binding to S1PR1 on lymphocytes to facilitate lymphocyte migration to inflamed tissues, and increased S1P was found in the intestinal mucosa of IBD patients. Notably, there is an interaction between the distribution of gut bacteria and SphK-S1P signaling in the intestinal epithelium. S1P-S1PR signaling can also regulate the functions of intestinal epithelial cells (IECs) in mucosa, including cell proliferation and apoptosis. Additionally, increased S1P in immune cells of the lamina propria aggravates the inflammatory response by increasing the production of proinflammatory cytokines. Several novel drugs targeted at S1PRs have recently been used for IBD treatment. This review provides an overview of the S1P-S1PR signaling pathway and, in particular, summarizes the various roles of S1P in the gut mucosal microenvironment to deeply explore the function of S1P-S1PR signaling during intestinal inflammation and, more importantly, to identify potential therapeutic targets for IBD in the SphK-S1P-S1PR axis.

Fecal microbiota transplantation refurbishes the crypt-associated microbiota in ulcerative colitis

A crypt autochthonous microbial population called crypt-associated microbiota (CAM) is localized intimately with gut regenerative and immune machinery. The present report utilizes laser capture microdissection coupled with 16S amplicon sequencing to characterize the CAM in patients with ulcerative colitis (UC) before and after fecal microbiota transplantation with anti-inflammatory diet (FMT-AID). Compositional differences in CAM and its interactions with mucosa-associated microbiota (MAM) were compared between the non-IBD controls and in patients with UC pre- and post-FMT (n = 26). Distinct from the MAM, CAM is dominated by aerobic members of Actinobacteria and Proteobacteria and exhibits resilience of diversity. CAM underwent UC-associated dysbiosis and demonstrated restoration post-FMT-AID. These FMT-restored CAM taxa correlated negatively with disease activity in patients with UC. The positive effects of FMT-AID extended further in refurbishing CAM-MAM interactions, which were obliterated in UC. These results encourage investigation into host-microbiome interactions established by CAM, to understand their role in disease pathophysiology.

The Association of Antibiotic Exposure with New-Onset Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

INTRODUCTION

The role of antibiotics in the development of inflammatory bowel disease (IBD) remains controversial, primarily due to conflicting data from individual studies. We conduct a systematic review and meta-analysis to study the effect of antibiotic exposure on IBD development.

METHODOLOGY

The MEDLINE and Cochrane CENTRAL databases were queried from their inception to April 2021 for published articles studying the association between antibiotic exposure and new-onset IBD. Our analysis was stratified by timing of antibiotic exposure - exposure in childhood and any lifetime exposure. Adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs) from each study were pooled using a random-effects model.

RESULTS

10 case-control studies and 2 cohort studies (N=29,880 IBD patients and N=715,548 controls) were included. Patients with Crohn's Disease (CD), compared with controls, were associated significantly with antibiotic exposure in childhood and any lifetime exposure to antibiotics (OR 1.52 [1.23-1.87]; p<0.00001). Patients with Ulcerative Colitis (UC), compared with controls, reported non-significant association with antibiotic exposure in childhood and any lifetime exposure. (OR 1.11 [0.93-1.33]; p=0.25) CONCLUSION: This meta-analysis suggests that exposure to antibiotics significantly increases the odds of developing CD and IBD in general. These findings re-emphasize the importance of cautious and judicious use of antibiotics.

The potential of tailoring the gut microbiome to prevent and treat cardiometabolic disease

Despite milestones in preventive measures and treatment, cardiovascular disease (CVD) remains associated with a high burden of morbidity and mortality. The protracted nature of the development and progression of CVD motivates the identification of early and complementary targets that might explain and alleviate any residual risk in treated patients. The gut microbiota has emerged as a sentinel between our inner milieu and outer environment and relays a modified risk associated with these factors to the host. Accordingly, numerous mechanistic studies in animal models support a causal role of the gut microbiome in CVD via specific microbial or shared microbiota-host metabolites and have identified converging mammalian targets for these signals. Similarly, large-scale cohort studies have repeatedly reported perturbations of the gut microbial community in CVD, supporting the translational potential of targeting this ecological niche, but the move from bench to bedside has not been smooth. In this Review, we provide an overview of the current evidence on the interconnectedness of the gut microbiome and CVD against the noisy backdrop of highly prevalent confounders in advanced CVD, such as increased metabolic burden and polypharmacy. We further aim to conceptualize the molecular mechanisms at the centre of these associations and identify actionable gut microbiome-based targets, while contextualizing the current knowledge within the clinical scenario and emphasizing the limitations of the field that need to be overcome.

Higher alpha diversity and Lactobacillus blooms are associated with better engraftment after Fecal Microbiota Transplant in Inflammatory Bowel Disease

Background

Fecal Microbiota Transplant (FMT) has proven effective in treating recurrent Clostridioides difficile infection (rCDI) and has shown some success in treating inflammatory bowel diseases (IBD). There is emerging evidence that host engraftment of donor taxa is a tenet of successful FMT. However, there is little known regarding predictors of engraftment. We undertook a double-blind, randomized, placebo-controlled pilot study to characterize the response to FMT in children and young adults with mild to moderate active Crohn's disease (CD) and ulcerative colitis (UC).

Results

Subjects with CD or UC were randomized to receive antibiotics and weekly FMT or placebo in addition to baseline medications. The treatment arm received seven days of antibiotics followed by FMT enema and then capsules weekly for seven weeks. We enrolled four subjects with CD and 11 with UC, ages 14-29 years. Due to weekly stool sampling, we were able to create a time series of alpha diversity, beta diversity and engraftment as they related to clinical response. Subjects exhibited a wide range of microbial diversity and donor engraftment as FMT progressed. Specifically, engraftment ranged from 26% to 90% at week 2 and 3% to 92% at two months. Consistent with the current literature, increases over time of both alpha diversity (p< 0.05) and donor engraftment (p< 0.05) correlated with improved clinical response. Additionally, our weekly time series enabled an investigation into the clinical and microbial correlates of engraftment at various time points. We discovered that the post-antibiotic but pre-FMT time point, often overlooked in FMT trials, was rich in microbial correlates of eventual engraftment. Greater residual alpha diversity after antibiotic treatment was positively correlated with engraftment and subsequent clinical response. Interestingly, a transient rise in the relative abundance of Lactobacillus was also positively correlated with engraftment, a finding that we recapitulated with our analysis of another FMT trial with publicly available weekly sequencing data.

Conclusions

We found that higher residual alpha diversity and Lactobacillus blooms after antibiotic treatment correlated with improved engraftment and clinical response to FMT. Future studies should closely examine the host microbial communities pre-FMT and the impact of antibiotic preconditioning on engraftment and response.

Immunological consequences of microbiome-based therapeutics

The complex network of microscopic organisms living on and within humans, collectively referred to as the microbiome, produce wide array of biologically active molecules that shape our health. Disruption of the microbiome is associated with susceptibility to a range of diseases such as cancer, diabetes, allergy, obesity, and infection. A new series of next-generation microbiome-based therapies are being developed to treat these diseases by transplanting bacteria or bacterial-derived byproducts into a diseased individual to reset the recipient's microbiome and restore health. Microbiome transplantation therapy is still in its early stages of being a routine treatment option and, with a few notable exceptions, has had limited success in clinical trials. In this review, we highlight the successes and challenges of implementing these therapies to treat disease with a focus on interactions between the immune system and microbiome-based therapeutics. The immune activation status of the microbiome transplant recipient prior to transplantation has an important role in supporting bacterial engraftment. Following engraftment, microbiome transplant derived signals can modulate immune function to ameliorate disease. As novel microbiome-based therapeutics are developed, consideration of how the transplants will interact with the immune system will be a key factor in determining whether the microbiome-based transplant elicits its intended therapeutic effect.

Efficacy and safety of fecal microbiota transplantation via colonoscopy as add-on therapy in patients with mild-to-moderate ulcerative colitis: A randomized clinical trial

Introduction

Growing evidence supports the effectiveness of fecal microbiota transplantation (FMT) in treating ulcerative colitis (UC), although its effects seem to depend on the method of introduction, the number of procedures, the donor material, and the severity of UC.

Aim

This study aimed to assess FMT's clinical and microbiological efficacy, tolerability, and safety in patients with mild-to-moderate UC.

Material and methods

Patients with mild-to-moderate UC were randomized into two groups. The first group (standard-care, n = 27) was treated with basic therapy-mesalazine-at a daily dose of 3 g (2 g orally + 1 g rectally). In the second group (FMT group, n = 26), while taking mesalazine at the indicated dose, each patient with UC as add-on therapy underwent a single FMT procedure with fresh material delivered by colonoscopy from a healthy donor. The clinical efficacy of treatment in both groups was evaluated after 4 and 8 weeks. The primary outcome was remission of UC, defined as a partial Mayo score ≤2, and decreased fecal calprotectin. All patients underwent bacteriological examination of feces for quantitative microbiota composition changes.

Results

Clinical response in the form of a significant decrease in stool frequency and a tendency to normalize its consistency after 4 weeks was detected in 14 (51.9%) patients of the standard care group and 16 patients (61.5%) of the FMT group (p = 0.583). The Mayo score in the standard care group was 3.59 ± 1.21 and in the FMT group-3.15±1.04 (p=0.166). After 8 weeks, the main primary endpoint was achieved in 70.4% of the standard-care group patients as compared to 84.6% of participants who received FMT as add-on therapy (p = 0.215). A more pronounced decrease in Mayo score was observed in the FMT group compared to the standard-care group (1.34 ± 1.44 vs. 2.14 ± 1.4; p = 0.045). All patients also showed a significant decrease in fecal calprotectin levels, which correlated with clinical data, stool frequency, and clinical remission. An improvement in gut microbiota composition was noted in both groups, albeit it was significantly more pronounced in the FMT group.

Conclusions

FTM in patients with mild-to-moderate UC is a well-tolerated, effective, and safe method of treatment in comparison to basic therapy.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT05538026?term=kobyliak&draw=2&rank=4, identifier: NCT05538026.

Fecal Microbiota Transplantation Research over the Past Decade: Current Status and Trends

Background

Fecal microbiota transplantation (FMT) is a current research hotspot, with a surge in the output of publications over the past decade. This study dedicates to the exploration of the research status and highlights significant themes and future trends in FMT research with the aid of bibliometric analysis.

Methods

FMT publications from 2012 to 2021 were retrieved on August 12, 2022, using the SCI-Expanded of Web of Science (WoS). The Bibliometrix in R program, Microsoft Office Excel, VOSviewer, and CiteSpace were utilized for bibliometrics and visual analysis, revealing the main publications, journals, countries, agencies, authors, and keywords distribution in FMT research.

Results

There were 2,931 papers included. FMT research presented a growing trend from 2012 to 2021. The countries with the most publications and contributions in FMT area were China and the United States. The high-yield institutions were Harvard University, Udice French Research Universities, and the University of California System. The primary authors were Nieuwdorp Max, Allegretti Jessica R, and Kassam Zain. Frontiers in Microbiology and Science were the top-ranked journals in publications and total citations, respectively. The important topics primarily included FMT-related mechanisms and the usage of FMT in Clostridium difficile infection (CDI), inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), metabolic disease, neurological disorders, and psychiatric disorders. Future research would primarily concentrate on neurological disorders, chemotherapy and immunotherapy for malignant tumors, and FMT-related consensus and guidelines.

Conclusion

With the help of bibliometric analysis, we were able to obtain the understanding of the status and trends of global FMT-related research. The field of FMT is undergoing tremendous progress, and our findings can guide clinical researchers' and practitioners' future work in the rapidly evolving field of FMT.

Hot topics on fecal microbiota transplantation for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic intestinal mucosal inflammatory disease with complex etiology. Traditional anti-inflammatory treatment regimens have yielded unsatisfactory results. As research continues to deepen, it has been found that the gut microbiota of patients with IBD is generally altered. The presence of microorganisms in the human gastrointestinal tract is inextricably linked to the regulation of health and disease. Disruption of the microbiotic balance of microbiota in the gastrointestinal tract is called dysbiosis, which leads to disease. Therefore, in recent years, the exploration of therapeutic methods to restore the homeostasis of the gut microbiota has attracted attention. Moreover, the use of the well-established fecal microbiota transplantation (FMT) regimen for the treatment of Clostridioides difficile infection has attracted the interest of IBD researchers. Therefore, there are an increasing number of clinical studies regarding FMT for IBD treatment. However, a series of questions regarding FMT in the treatment of IBD warrants further investigation and discussion. By reviewing published studies, this review explored hot topics such as the efficacy, safety, and administration protocol flow of FMT in the treatment of IBD. Different administration protocols have generally shown reassuring results with significant efficacy and safety. However, the FMT treatment regimen needs to be further optimized. We believe that in the future, individual customized or standard FMT implementation will further enhance the relevance of FMT in the treatment of IBD.

Microbial Modulation in Inflammatory Bowel Diseases

Gut dysbiosis is one of prominent features in inflammatory bowel diseases (IBDs) which are of an unknown etiology. Although the cause-and-effect relationship between IBD and gut dysbiosis remains to be elucidated, one area of research has focused on the management of IBD by modulating and correcting gut dysbiosis. The use of antibiotics, probiotics either with or without prebiotics, and fecal microbiota transplantation from healthy donors are representative methods for modulating the intestinal microbiota ecosystem. The gut microbiota is not a simple assembly of bacteria, fungi, and viruses, but a complex organ-like community system composed of numerous kinds of microorganisms. Thus, studies on specific changes in the gut microbiota depending on which treatment option is applied are very limited. Here, we review previous studies on microbial modulation as a therapeutic option for IBD and its significance in the pathogenesis of IBD.

Nutritional factors influencing microbiota-mediated colonization resistance of the oral cavity: A literature review

The oral cavity is a key biocenosis for many distinct microbial communities that interact with both the external environment and internal body systems. The oral microbiota is a vital part of the human microbiome. It has been developed through mutual interactions among the environment, host physiological state, and microbial community composition. Indigenious microbiota of the oral cavity is one of the factors that prevent adhesion and invasion of pathogens on the mucous membrane, i.e., the development of the infectious process and thereby participating in the implementation of one of the mechanisms of local immunity-colonization resistance. The balance between bacterial symbiosis, microbial virulence, and host resistance ensures the integrity of the oral cavity. In this review we have tried to address how nutritional factors influence integrity of the oral indigenous microbiota and its involvement in colonization resistance.

Drivers and determinants of strain dynamics following fecal microbiota transplantation

Fecal microbiota transplantation (FMT) is a therapeutic intervention for inflammatory diseases of the gastrointestinal tract, but its clinical mode of action and subsequent microbiome dynamics remain poorly understood. Here we analyzed metagenomes from 316 FMTs, sampled pre and post intervention, for the treatment of ten different disease indications. We quantified strain-level dynamics of 1,089 microbial species, complemented by 47,548 newly constructed metagenome-assembled genomes. Donor strain colonization and recipient strain resilience were mostly independent of clinical outcomes, but accurately predictable using LASSO-regularized regression models that accounted for host, microbiome and procedural variables. Recipient factors and donor–recipient complementarity, encompassing entire microbial communities to individual strains, were the main determinants of strain population dynamics, providing insights into the underlying processes that shape the post-FMT gut microbiome. Applying an ecology-based framework to our findings indicated parameters that may inform the development of more effective, targeted microbiome therapies in the future, and suggested how patient stratification can be used to enhance donor microbiota colonization or the displacement of recipient microbes in clinical practice.

Research trends in ulcerative colitis: A bibliometric and visualized study from 2011 to 2021

Background: Ulcerative colitis (UC) is an idiopathic inflammatory bowel disease with repeated relapses and remissions. Despite decades of effort, numerous aspects, including the initiating event and pathogenesis of UC, still remain ambiguous, which requires ongoing investigation. Given the mass of publications on UC, there are multidimensional challenges to evaluating the scientific impact of relevant work and identifying the current foci of the multifaceted disease. Accordingly, herein, we aim to assess the global growth of UC research production, analyze patterns of research areas, and evaluate trends in this area.

Methods: The Web of Science Core Collection of Clarivate Analytics was searched for articles related to UC published from 2011 to 2021. Microsoft Office Excel 2019 was used to visualize the number of publications over time. Knowledge maps were generated using CiteSpace and VOSviewer to analyze collaborations among countries, institutions, and authors and to present the journey of UC research as well as to reveal the current foci of UC research.

Results: A total of 5,088 publications were evaluated in the present study. China had the most publications (1,099, 22.5%). Univ Calif San Diego was the most productive institution (126, 2.48%). William J Sandborn published the greatest number of articles (100, 1.97%). Toshifumi Hibi was the most influential author in the field with a betweenness centrality of 0.53. Inflammatory bowel diseases was identified as the most prolific journal (379, 7.45%). Gastroenterology was the most co-cited journal (3,730, 4.02%). “Vedolizumab,” “tofacitinib,” “Faecalibacterium prausnitzii,” “fecal microbiota transplantation (FMT),” “toll-like receptor 4,” and “nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome” were considered the hot topics.

Conclusion: In UC research, manuscripts that had high impacts on the scientific community provided an evidence base. UC therapy has entered the era of personalized and precision therapy. As research on FMT, anti-integrin antibodies, Janus kinase inhibitors, and anti-tumor necrosis factor drugs continues to grow, their use in the clinical setting may also expand.

Gastrointestinal Microbiome and Multiple Health Outcomes: Umbrella Review

In recent years, there has been growing concern about the impact of the gastrointestinal microbiome on human health outcomes. To clarify the evidence for a link between the gastrointestinal microbiome and a variety of health outcomes in humans, we conducted an all-encompassing review of meta-analyses and systematic reviews that included 195 meta-analyses containing 950 unique health outcomes. The gastrointestinal microbiome is related to mortality, gastrointestinal disease, immune and metabolic outcomes, neurological and psychiatric outcomes, maternal and infant outcomes, and other outcomes. Existing interventions for intestinal microbiota (such as probiotics, fecal microbiota transplant, etc.) are generally safe and beneficial to a variety of human health outcomes, but the quality of evidence is not high, and more detailed and well-designed randomized controlled trials are necessary.

An updated systematic review and meta-analysis of fecal microbiota transplantation for the treatment of ulcerative colitis

BACKGROUND

Fecal microbiota transplantation (FMT) as a promising therapy for ulcerative colitis (UC) remains controversial. We conducted a systematic review and meta-analysis to assess the efficiency and safety of FMT as a treatment for UC.

METHODS

The target studies were identified by searching PubMed, EMBASE, the Cochrane Library, Web of Science, and ClinicalTrials and by manual supplementary retrieval. We conducted a general review and quantitative synthesis of included studies. We used the RevMan and Stata programs in the meta-analysis. The outcomes were total remission, clinical remission, steroid-free remission, and serious adverse events. We also performed subgroup analyses based on different populations.

RESULTS

A total of 34 articles were included in the general review. Only 16 articles, including 4 randomized controlled trials, 2 controlled clinical trials, and 10 cohort studies, were selected for the meta-analysis. We found that donor FMT might be more effective than placebo for attaining total remission (risk ratio [RR]: 2.77, 95% confidence interval [CI]: 1.54-4.98; P = .0007), clinical remission (RR: 0.33, 95% CI: 0.24-0.41; P < .05), and steroid-free remission (RR: 3.63, 95% CI: 1.57-8.42; P = .003), but found no statistically significant difference in the incidence of serious adverse events (RR: 0.88, 95% CI: 0.34-2.31, P = .8). The subgroup analyses revealed significant differences between the pooled clinical remission rates for different regions, degrees of severity of the disease, and patients with steroid- or nonsteroid-dependent UC.

CONCLUSIONS

FMT can achieve clinical remission and clinical response in patients with UC.

Fecal microbiota transplantation: a review on current formulations in Clostridioides difficile infection and future outlooks

INTRODUCTION

The role of the gut microbiota in health and the pathogenesis of several diseases has been highlighted in recent years. Even though the precise mechanisms involving the microbiome in these ailments are still unclear, microbiota-modulating therapies have been developed. Fecal microbiota transplantation (FMT) has shown significant results against Clostridioides difficile infection (CDI), and its potential has been investigated for other diseases. Unfortunately, the technical aspects of the treatment make it difficult to implement. Pharmaceutical technology approaches to encapsulate microorganisms could play an important role in providing this treatment and render the treatment modalities easier to handle.

AREAS COVERED

After an overview of CDI, this narrative review aims to discuss the current formulations for FMT and specifically addresses the technical aspects of the treatment. This review also distinguishes itself by focusing on the hurdles and emphasizing the possible improvements using pharmaceutical technologies.

EXPERT OPINION

FMT is an efficient treatment for recurrent CDI. However, its standardization is overlooked. The approach of industrial and hospital preparations of FMT are different, but both show promise in their respective methodologies. Novel FMT formulations could enable further research on dysbiotic diseases in the future.

Multiomics to elucidate inflammatory bowel disease risk factors and pathways

Inflammatory bowel disease (IBD) is an immune-mediated disease of the intestinal tract, with complex pathophysiology involving genetic, environmental, microbiome, immunological and potentially other factors. Epidemiological data have provided important insights into risk factors associated with IBD, but are limited by confounding, biases and data quality, especially when pertaining to risk factors in early life. Multiomics platforms provide granular high-throughput data on numerous variables simultaneously and can be leveraged to characterize molecular pathways and risk factors for chronic diseases, such as IBD. Herein, we describe omics platforms that can advance our understanding of IBD risk factors and pathways, and available omics data on IBD and other relevant diseases. We highlight knowledge gaps and emphasize the importance of birth, at-risk and pre-diagnostic cohorts, and neonatal blood spots in omics analyses in IBD. Finally, we discuss network analysis, a powerful bioinformatics tool to assemble high-throughput data and derive clinical relevance.

Long-term Outcomes Following Multiply Recurrent Clostridioides difficile Infection and Fecal Microbiota Transplantation

BACKGROUND AND AIMS

Fecal microbiota transplantation (FMT) is a commonly used therapy for multiply recurrent Clostridioides difficile (mrCDI). By altering the gut microbiota, there is the potential for FMT to impact the risk for cardiometabolic, intestinal or immune-mediated conditions. Likewise, the microbiota disturbance associated with mrCDI could potentially lead to these conditions. We aimed to assess the associations of mrCDI and FMT with cardiometabolic, immune-mediated diseases, and irritable bowel syndrome.

METHODS

This retrospective cohort study using a United States commercial claims database included persons diagnosed with CDI or undergoing FMT. We created 2 pairwise comparisons: mrCDI vs non-mrCDI, and non-mrCDI or mrCDI treated with FMT vs mrCDI without FMT.

RESULTS

We found no significant association between mrCDI (vs non-mrCDI) and inflammatory bowel disease (adjusted hazard ratio (aHR) = 1.65; 95% confidence interval, 0.67-4.04), rheumatoid arthritis (HR = 0.86; 0.47-1.56), psoriasis (HR = 0.72; 0.23-2.27), diabetes (aHR = 0.97; 0.67-1.40), hypertension (aHR = 1.05; 0.76-1.44), myocardial infarction (aHR = 0.82; 0.63-1.06), stroke (aHR = 0.83; 0.62-1.12), or irritable bowel syndrome (HR = 0.94; 0.61-1.45). Similarly, we found no association of CDI with FMT (vs mrCDI without FMT) and diabetes (aHR = 0.92; 0.27-3.11), hypertension (aHR = 1.41; 0.64-3.15), stroke (aHR = 1.27; 0.69-2.34) or inflammatory bowel syndrome (aHR = 0.80; 0.26-2.46). However, the incidence of myocardial infarction was increased following FMT (aHR = 1.68; 1.01-2.81).

CONCLUSION

Relative to those with CDI, persons with mrCDI do not appear to be intrinsically at higher risk of cardiometabolic, immune-mediated diseases, or irritable bowel syndrome. However, those who underwent FMT for CDI had a higher incidence of myocardial infarction. Future studies should assess this association to assess reproducibility.

Next-generation sequencing: insights to advance clinical investigations of the microbiome

Next-generation sequencing (NGS) technology has advanced our understanding of the human microbiome by allowing for the discovery and characterization of unculturable microbes with prediction of their function. Key NGS methods include 16S rRNA gene sequencing, shotgun metagenomic sequencing, and RNA sequencing. The choice of which NGS methodology to pursue for a given purpose is often unclear for clinicians and researchers. In this Review, we describe the fundamentals of NGS, with a focus on 16S rRNA and shotgun metagenomic sequencing. We also discuss pros and cons of each methodology as well as important concepts in data variability, study design, and clinical metadata collection. We further present examples of how NGS studies of the human microbiome have advanced our understanding of human disease pathophysiology across diverse clinical contexts, including the development of diagnostics and therapeutics. Finally, we share insights as to how NGS might further be integrated into and advance microbiome research and clinical care in the coming years.

A Randomized Placebo-Controlled Trial of Combination Therapy With Post-triple-antibiotic-therapy Fecal Microbiota Transplantation and Alginate for Ulcerative Colitis: Protocol

Background

Fecal microbiota transplantation (FMT) has been widely performed for ulcerative colitis (UC) treatment at the clinical trial stage. Previous reports have used multiple FMT methods to enhance the colonization of healthy donor microbiota in the recipient's intestines. FMT following triple antibiotic therapy with amoxicillin, fosfomycin, and metronidazole (A-FMT) is not only effective but also requires only one FMT, which improves dysbiosis caused by reduced Bacteroidetes diversity in patients with UC. Alginate and its derivatives have the potential to induce the growth of intestinal bacteria including Bacteroides members and produce short-chain fatty acids (SCFAs), which are beneficial in regulating overactive autoimmunity. Our trial aims to investigate whether post-intervention with alginate, which can improve the intestinal environment, will enhance the therapeutic effect of A-FMT in UC and increase the long-term remission rate.

Methods and Analysis

This trial is a double-blinded, randomized, placebo-controlled, parallel assignment trial. Patients with UC and fecal donation candidates will undergo strict screening before being involved in the trial. Eligible patients are randomly divided into two groups: one group will drink one bottle of alginate twice a day for 8 consecutive weeks after A-FMT, while the other group will take a placebo instead of the alginate drink. The primary endpoints are the changes in the Total Mayo Score at 8 weeks after study initiation and A-FMT from baseline. The secondary endpoint is the comparison of clinical features, microbiota, and metabolomic analysis before and after 8 weeks of study food intake. Changes at 6, 12, 18, and 24 months after A-FMT will be assessed. Finally, a subpopulation analysis of the relationship between patients and donors is an exploratory endpoint.

Discussion

The FMT post-treatment used in this study is an oral alginate drink that is easily accepted by patients. If the regimen achieves the desired results, it can further improve the A-FMT regimen and provide evidence for clinical practice guidelines for UC.

Clinical Trial Registration

https://jrct.niph.go.jp/latest-detail/jRCTs031200103, identifier: jRCTs031200103.

Donor Screening Revisions of Fecal Microbiota Transplantation in Patients with Ulcerative Colitis

Fecal microbiota transplantation (FMT) has been recognized as a promising treatment for dysbiosis-related diseases. Since 2014, FMT has been utilized to treat ulcerative colitis (UC) in our clinical studies and has shown efficacy and safety. As donor screening (DS) is the primary step to ensure the safety of FMT, we report our experience with DS and present the screening results to improve the prospective DS criteria and provide references for future studies. The donor candidates were screened according to the DS criteria. The first DS criteria were proposed in June 2014 and revised substantially in May 2018. We further sorted the screening results and costs of laboratory tests. From June 2014 to April 2018, the DS eligibility rate was 50%. The total laboratory testing cost for each candidate was JPY 17,580/USD 160.21. From May 2018 to September 2021, the DS eligibility rate was 25.6%. The total laboratory testing cost for each candidate was JPY 40,740/USD 371.36. The reduction in donor eligibility rates due to more stringent criteria should be considered for cost and safety. Studies must consider the latest updates and make timely modifications in the DS criteria to ensure patient safety.

The Gut Microbiome in Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS)

Myalgic encephalomyelitis (ME) or Chronic Fatigue Syndrome (CFS) is a neglected, debilitating multi-systemic disease without diagnostic marker or therapy. Despite evidence for neurological, immunological, infectious, muscular and endocrine pathophysiological abnormalities, the etiology and a clear pathophysiology remains unclear. The gut microbiome gained much attention in the last decade with manifold implications in health and disease. Here we review the current state of knowledge on the interplay between ME/CFS and the microbiome, to identify potential diagnostic or interventional approaches, and propose areas where further research is needed. We iteratively selected and elaborated on key theories about a correlation between microbiome state and ME/CFS pathology, developing further hypotheses. Based on the literature we hypothesize that antibiotic use throughout life favours an intestinal microbiota composition which might be a risk factor for ME/CFS. Main proposed pathomechanisms include gut dysbiosis, altered gut-brain axis activity, increased gut permeability with concomitant bacterial translocation and reduced levels of short-chain-fatty acids, D-lactic acidosis, an abnormal tryptophan metabolism and low activity of the kynurenine pathway. We review options for microbiome manipulation in ME/CFS patients including probiotic and dietary interventions as well as fecal microbiota transplantations. Beyond increasing gut permeability and bacterial translocation, specific dysbiosis may modify fermentation products, affecting peripheral mitochondria. Considering the gut-brain axis we strongly suspect that the microbiome may contribute to neurocognitive impairments of ME/CFS patients. Further larger studies are needed, above all to clarify whether D-lactic acidosis and early-life antibiotic use may be part of ME/CFS etiology and what role changes in the tryptophan metabolism might play. An association between the gut microbiome and the disease ME/CFS is plausible. As causality remains unclear, we recommend longitudinal studies. Activity levels, bedridden hours and disease progression should be compared to antibiotic exposure, drug intakes and alterations in the composition of the microbiota. The therapeutic potential of fecal microbiota transfer and of targeted dietary interventions should be systematically evaluated.

Contribution of the Gut Microbiota to Intestinal Fibrosis in Crohn's Disease

In Crohn's disease (CD), intestinal fibrosis is a critical determinant of a patient's prognosis. Although inflammation may be a prerequisite for the initiation of intestinal fibrosis, research shows that the progression or continuation of intestinal fibrosis can occur independently of inflammation. Thus, once initiated, intestinal fibrosis may persist even if medical treatment controls inflammation. Clearly, an understanding of the pathophysiological mechanisms of intestinal fibrosis is required to diminish its occurrence. Accumulating evidence suggests that the gut microbiota contributes to the pathogenesis of intestinal fibrosis. For example, the presence of antibodies against gut microbes can predict which CD patients will have intestinal complications. In addition, microbial ligands can activate intestinal fibroblasts, thereby inducing the production of extracellular matrix. Moreover, in various animal models, bacterial infection can lead to the development of intestinal fibrosis. In this review, we summarize the current knowledge of the link between intestinal fibrosis in CD and the gut microbiota. We highlight basic science and clinical evidence that the gut microbiota can be causative for intestinal fibrosis in CD and provide valuable information about the animal models used to investigate intestinal fibrosis.

The Human Virome: Viral Metagenomics, Relations with Human Diseases, and Therapeutic Applications

The human body is colonized by a wide range of microorganisms. The field of viromics has expanded since the first reports on the detection of viruses via metagenomic sequencing in 2002. With the continued development of reference materials and databases, viral metagenomic approaches have been used to explore known components of the virome and discover new viruses from various types of samples. The virome has attracted substantial interest since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic. Increasing numbers of studies and review articles have documented the diverse virome in various sites in the human body, as well as interactions between the human host and the virome with regard to health and disease. However, there have been few studies of direct causal relationships. Viral metagenomic analyses often lack standard references and are potentially subject to bias. Moreover, most virome-related review articles have focused on the gut virome and did not investigate the roles of the virome in other sites of the body in human disease. This review presents an overview of viral metagenomics, with updates regarding the relations between alterations in the human virome and the pathogenesis of human diseases, recent findings related to COVID-19, and therapeutic applications related to the human virome.

Consistent changes in the intestinal microbiota of Atlantic salmon fed insect meal diets

BACKGROUND

Being part of fish's natural diets, insects have become a practical alternative feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon (Salmo salar) were fed either a commercially relevant reference diet or an insect meal diet wherein black soldier fly (Hermetia illucens) larvae meal comprised 60% of total ingredients. Microbiota of digesta and mucosa origin from the proximal and distal intestine were collected and profiled along with feed and water samples.

RESULTS

The insect meal diet markedly modulated the salmon intestinal microbiota. Salmon fed the insect meal diet showed similar or lower alpha-diversity indices in the digesta but higher alpha-diversity indices in the mucosa. A group of bacterial genera, dominated by members of the Bacillaceae family, was enriched in salmon fed the insect meal diet, which confirms our previous findings in a seawater feeding trial. We also found that microbiota in the intestine closely resembled that of the feeds but was distinct from the water microbiota. Notably, bacterial genera associated with the diet effects were also present in the feeds.

CONCLUSIONS

We conclude that salmon fed the insect meal diets show consistent changes in the intestinal microbiota. The next challenge is to evaluate the extent to which these alterations are attributable to feed microbiota and dietary nutrients, and what these changes mean for fish physiology and health.

Current Status and Future Therapeutic Options for Fecal Microbiota Transplantation

The intestinal microbiota plays an important role in maintaining human health, and its alteration is now associated with the development of various gastrointestinal (ulcerative colitis, irritable bowel syndrome, constipation, etc.) and extraintestinal diseases, such as cancer, metabolic syndrome, neuropsychiatric diseases. In this context, it is not surprising that gut microbiota modification methods may constitute a therapy whose potential has not yet been fully investigated. In this regard, the most interesting method is thought to be fecal microbiota transplantation, which consists of the simultaneous replacement of the intestinal microbiota of a sick recipient with fecal material from a healthy donor. This review summarizes the most interesting findings on the application of fecal microbiota transplantation in gastrointestinal and extraintestinal pathologies.

Major yolk protein from sea cucumber (Stichopus japonicus) attenuates acute colitis via regulation of microbial dysbiosis and inflammatory responses

Inflammatory bowel disease afflicted individuals and most medications have adverse effects. The objection of this study is to investigate whether the major yolk protein (MYP) could aid in the remission of colitis. The function of MYP on acute colitis was assessed through a dextran sulfate sodium -induced colitis mice model. Compared to the model group, the anti-inflammatory cytokines increased significantly in the MYP group, whereas the pro-inflammatory cytokines were not significantly different between the model and treatment group. The results also showed that supplementation of MYP improved the shift in microbial community composition of mice with colitis induced by DSS. In addition, MYP supplementation enriched the contents of fecal short-chain fatty acids. The alleviation of MYP on the colitis was probably related to repair the dysbiosis state of colonic microbiota, which thus induced an increase in short-chain fatty acids level and secrete anti-inflammatory cytokines (IL-4 and IL-10). In sum, oral MYP may be a potential candidate for the attenuating of acute colitis.

Nutritional Therapies and Their Influence on the Intestinal Microbiome in Pediatric Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic, autoimmune disorder of the gastrointestinal tract with numerous genetic and environmental risk factors. Patients with Crohn’s disease (CD) or ulcerative colitis (UC) often demonstrate marked disruptions of their gut microbiome. The intestinal microbiota is strongly influenced by diet. The association between the increasing incidence of IBD worldwide and increased consumption of a westernized diet suggests host nutrition may influence the progression or treatment of IBD via the microbiome. Several nutritional therapies have been studied for the treatment of CD and UC. While their mechanisms of action are only partially understood, existing studies do suggest that diet-driven changes in microbial composition and function underlie the diverse mechanisms of nutritional therapy. Despite existing therapies for IBD focusing heavily on immune suppression, nutrition is an important treatment option due to its superior safety profile, potentially low cost, and benefits for growth and development. These benefits are increasingly important to patients. In this review, we will describe the clinical efficacy of the different nutritional therapies that have been described for the treatment of CD and UC. We will also describe the effects of each nutritional therapy on the gut microbiome and summarize the strength of the literature with recommendations for the practicing clinician.

Whole blood resuscitation restores intestinal perfusion and influences gut microbiome diversity

OBJECTIVE

Gut dysbiosis, an imbalance in the gut microbiome, occurs after trauma, which may be ameliorated with transfusion. We hypothesized that gut hypoperfusion following trauma causes dysbiosis and that whole blood (WB) resuscitation mitigates these effects.

METHODS

Anesthetized rats underwent sham (S; laparotomy only, n = 6); multiple injuries (T; laparotomy, liver and skeletal muscle crush injuries, and femur fracture, n = 5); multiple injuries and 40% hemorrhage (H; n = 7); and multiple injuries, hemorrhage, and WB resuscitation (R; n = 7), which was given as 20% estimated blood volume from donor rats 1 hour posttrauma. Baseline cecal mesenteric tissue oxygen (O2) concentration was measured following laparotomy and at 1 hour and 2 hours posttrauma. Fecal samples were collected preinjury and at euthanasia (2 hours). 16S rRNA sequencing was performed on purified DNA, and diversity and phylogeny were analyzed with QIIME (Knight Lab, La Jolla, CA; Caporaso Lab, Flagstaff, AZ) using the Greengenes 16S rRNA database (operational taxonomic units; 97% similarity). α and β diversities were estimated using observed species metrics. Permutational analysis of variance was performed for overall significance.

RESULTS

In H rats, an average decline of 36% ± 3.6% was seen in the mesenteric O2 concentration at 1 hour without improvement by 2 hours postinjury, which was reversed following resuscitation at 2 hours postinjury (4.1% ± 3.1% difference from baseline). There was no change in tissue O2 concentration in the S or T rats. β Diversity differed among groups for all measured indices except Bray-Curtis, with the spatial median of the S and R rats more similar compared with S and H rats (p < 0.05). While there was no difference in α diversity found among the groups, indices were significantly correlated with mesenteric O2 concentration. Members of the family Enterobacteriaceae were significantly enriched in only 2 hours.

CONCLUSION

Mesenteric perfusion after trauma and hemorrhage is restored with WB resuscitation, which influences β diversity of the gut microbiome. Whole blood resuscitation may also mitigate the effects of hemorrhage on intestinal dysbiosis, thereby influencing outcomes.

The Immunomodulatory Functions of Butyrate

The gastrointestinal (GI) system contains many different types of immune cells, making it a key immune organ system in the human body. In the last decade, our knowledge has substantially expanded regarding our understanding of the gut microbiome and its complex interaction with the gut immune system. Short chain fatty acids (SCFA), and specifically butyrate, play an important role in mediating the effects of the gut microbiome on local and systemic immunity. Gut microbial alterations and depletion of luminal butyrate have been well documented in the literature for a number of systemic and GI inflammatory disorders. Although a substantial knowledge gap exists requiring the need for further investigations to determine cause and effect, there is heightened interest in developing immunomodulatory therapies by means of reprogramming of gut microbiome or by supplementing its beneficial metabolites, such as butyrate. In the current review, we discuss the role of endogenous butyrate in the inflammatory response and maintaining immune homeostasis within the intestine. We also present the experimental models and human studies which explore therapeutic potential of butyrate supplementation in inflammatory conditions associated with butyrate depletion.

Effects of molecular weight of chitosan on anti-inflammatory activity and modulation of intestinal microflora in an ulcerative colitis model

This study investigated the therapeutic effects and mechanisms of chitosans (CSs) with different molecular weights on ulcerative colitis (UC). Three size classes of CSs (Mw ≤ 3, 50, and 200 kDa) were used in this study. The effect of large CSs (Mw ≤ 200 kDa) on UC was the best, followed by that of medium CSs (Mw ≤ 50 kDa), and that of small CSs (Mw ≤ 3 kDa) was the least in the LPS-induced Raw 264.7 cell model and DSS-induced UC mice model. The therapeutic mechanisms of three CSs are related to anti-oxidation, anti-inflammation, and regulation of immunoglobulin and intestinal flora by attenuating body weight loss, decreasing the disease activity index (DAI) and MPO activity, suppressing proinflammatory cytokines and IgG levels, down-regulating the level of oxidative stress, increasing anti-inflammatory cytokines, SOD activity and Prevotellaceae_UCG-001 levels, and reducing the abundance of Proteobacteria, Actinobacteria, and Escherichia-Shigella. In general, the molecular weight of CSs influences their efficacy against UC. CSs with an optimal molecular weight demonstrate good development prospects for ameliorating UC.

Adverse events of fecal microbiota transplantation: a meta-analysis of high-quality studies

BACKGROUND

Fecal microbiota transplantation (FMT) has shown excellent efficacy in treating Clostridioides difficile infection, as well as promise in several other diseases. The heightened interest is accompanied by concerns over adverse events (AE) and safety. To further understand that in FMT, we performed a systematic review of the literature and a meta-analysis of high-quality, prospective randomized controlled trials FMT.

METHODS

Studies were selected based on predefined exclusion criteria and were assessed for quality. Only prospective, randomized, controlled studies of high quality were included in the final analysis. Data were extracted on demographics, AE, indication, delivery method and follow-up duration.

RESULTS

Out of 334 articles reviewed, 9 high quality studies with 756 FMTs were selected for final analysis. The pooled rate of AE was 39.3% (95% confidence interval [CI] 0.19-0.642) as they were reported by 112 patients who received FMT. The SAE rate was 5.3% (95%CI 3.1-8.8%). The most common AE reported was abdominal pain, followed by diarrhea. The most common SAE was Clostridium difficile infection. Upper gastrointestinal tract delivery was associated with a higher rate of total AE, but not SAE.

CONCLUSIONS

Based on the selected studies, the AE rate of FMT is 39.3%, with most AE being mild and self-limiting. SAE were uncommon at 5.3%, and many were only possibly related to the FMT. Adherence to standardized reporting of AE as well as longitudinal studies and registries will help further clarify the safety of FMT in the future.

The Exopolysaccharide Produced by Lactobacillus paracasei IJH-SONE68 Prevents and Ameliorates Inflammatory Responses in DSS-Induced Ulcerative Colitis

Inflammatory bowel disease (IBD) is an autoimmune disease characterized by chronic inflammation of the gastrointestinal tract. IBD includes Crohn’s disease (CD) and ulcerative colitis (UC). CD can occur in any part of the gastrointestinal tract, whereas UC mainly occurs in the colon and rectum. We previously demonstrated that a novel exopolysaccharide (EPS) produced by a plant-derived bacterium, Lactobacillus paracasei IJH-SONE68, prevents and improves the inflammation in contact dermatitis model mice via oral administration. To evaluate the preventive effect of the EPS against other inflammatory diseases, in the present study, we employed dextran sulfate sodium (DSS)-induced UC model mice. The stool consistency, hematochezia, and colonic atrophy of the mice were improved by the orally administered EPS. We also evaluated the cytokine transcription. Overexpression of the mouse macrophage inflammatory protein 2 mRNA in the colon as a functional homolog of human interleukin-8 was decreased by the orally administered EPS. However, the expression of interleukin-10, which is known as an anti-inflammatory cytokine, was stimulated in the EPS-administrated group. Based on these results, we conclude that the IJH-SONE68-derived EPS is a promising lead material for the development of drugs useful in treating inflammatory diseases such as UC.

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.