Bifidobacterium-Rich Fecal Donor May Be a Positive Predictor for Successful Fecal Microbiota Transplantation in Patients with Irritable Bowel Syndrome

Faecal microbiota transplantation in children: A systematic review

AIM

Novel technologies offer insights into the potential role of the intestinal microbiota in human health and disease. Dysbiosis has been associated with several diseases, and it is thought to play a role in the pathogenesis of different gastrointestinal diseases. Faecal microbiota transplantation (FMT) is emerging as a method to modulate the gastrointestinal microbial ecosystem. While recurrent Clostridioides difficile infection is the recognised FMT indication, exploration of other therapeutic uses is ongoing.

METHODS

Following PRISMA guidelines, we conducted a systematic review, extracting 583 articles from Embase and PubMed (index date to October 2022).

RESULTS

The search yielded 58 studies for full review, with 50 included in the systematic review. Articles were categorised by FMT indication, study design, efficacy, adverse events, donor selection and administration route. FMT appears safe and effective for recurrent Clostridioides difficile infection, although severe adverse events are reported in children. However, there are currently insufficient data to support the use of FMT for other potential therapeutic indications (such as irritable or inflammatory bowel disease or obesity), beside the potential to decolonise multi-drug resistant organisms.

CONCLUSION

This underscores the need for randomised, controlled, prospective cohort studies in children to assess FMT effectiveness in diverse conditions and counteract publication bias.

Fecal Microbiota Transplantation Regulates Blood Pressure by Altering Gut Microbiota Composition and Intestinal Mucosal Barrier Function in Spontaneously Hypertensive Rats

Hypertension is accompanied by gut microbiota imbalance, but the role of bacteria in the pathogenesis of hypertension requires further study. In this study, we used fecal microbiota transplantation to determine the impact of microbiota composition on blood pressure in spontaneous hypertensive rats (SHRs), using normotensive Wistar Kyoto (WKY) rats as controls. SHRs were randomly divided into two groups (n = 10/group), SHR and SHR-T (SHR plus fecal transplantation) and WKY into WKY and WKY-T (WKY plus fecal transplantation). SHR-T received fecal transplantation from WKY, while WKY-T received fecal transplantation from SHR. Blood pressure was measured from the tail artery in conscious rats. 16S rDNA gene amplicon sequencing was used to analyze bacterial composition. Circulating levels of diamine oxidase, D-lactate, FITC-Dextrans, and lipopolysaccharide were determined. Hematoxylin and eosin (H&E) staining was used to observe structural changes in the intestinal mucosa. Immunofluorescence, Western blot, and RT-PCR were utilized to determine changes in the expression of tight junction proteins. Following cross fecal transplantation, blood pressure decreased in SHR and increased in WKY. Significant differences in gut microbial composition were found between hypertensive and normotensive rats, specifically regarding the relative abundance of lactic and butyric acid-producing bacteria. Changes in gut microbiota composition also impacted the intestinal mucosal barrier integrity. Moreover, fecal transplantation affected the expression of tight junction proteins that may impact intestinal mucosal permeability and structural integrity. Blood pressure may be associated with butyric acid-producing intestinal microbiota and its function in regulating the integrity of intestinal mucosal barrier.

Impacts of microbiota and its metabolites through gut-brain axis on pathophysiology of major depressive disorder

Major depressive disorder (MDD) is characterized by a high rate of recurrence and disability, which seriously affects the quality of life of patients. That's why a deeper understanding of the mechanisms of MDD pathology is an urgent task, and some studies have found that intestinal symptoms accompany people with MDD. The microbiota-gut-brain axis is the bidirectional communication between the gut microbiota and the central nervous system, which was found to have a strong association with the pathogenesis of MDD. Previous studies have focused more on the communication between the gut and the brain through neuroendocrine, neuroimmune and autonomic pathways, and the role of gut microbes and their metabolites in depression is unclear. Metabolites of intestinal microorganisms (e.g., tryptophan, kynurenic acid, indole, and lipopolysaccharide) can participate in the pathogenesis of MDD through immune and inflammatory pathways or by altering the permeability of the gut and blood-brain barrier. In addition, intestinal microbes can communicate with intestinal neurons and glial cells to affect the integrity and function of intestinal nerves. However, the specific role of gut microbes and their metabolites in the pathogenesis of MDD is not well understood. Hence, the present review summarizes how gut microbes and their metabolites are directly or indirectly involved in the pathogenesis of MDD.

Reduction of product composition variability using pooled microbiome ecosystem therapy and consequence in two infectious murine models

Growing evidence demonstrates the key role of the gut microbiota in human health and disease. The recent success of microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on its potential in conditions associated with gut dysbiosis, such as acute graft-versus-host disease, intestinal bowel diseases, neurodegenerative diseases, or even cancer. However, the difficulty in defining a "good" donor as well as the intrinsic variability of donor-derived products' taxonomic composition limits the translatability and reproducibility of these studies. Thus, the pooling of donors' feces has been proposed to homogenize product composition and achieve higher taxonomic richness and diversity. In this study, we compared the metagenomic profile of pooled products to corresponding single donor-derived products. We demonstrated that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria known to produce anti-inflammatory short chain fatty acids compared to single donor-derived products. We then evaluated pooled products' efficacy compared to corresponding single donor-derived products in Salmonella and C. difficile infectious mouse models. We were able to demonstrate that pooled products decreased pathogenicity by inducing a structural change in the intestinal microbiota composition. Single donor-derived product efficacy was variable, with some products failing to control disease progression. We further performed in vitro growth inhibition assays of two extremely drug-resistant bacteria, Enterococcus faecium vanA and Klebsiella pneumoniae oxa48, supporting the use of pooled microbiotherapies. Altogether, these results demonstrate that the heterogeneity of donor-derived products is corrected by pooled fecal microbiotherapies in several infectious preclinical models.IMPORTANCEGrowing evidence demonstrates the key role of the gut microbiota in human health and disease. Recent Food and Drug Administration approval of fecal microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on their potential to treat pathological conditions associated with gut dysbiosis. In this study, we combined metagenomic analysis with in vitro and in vivo studies to compare the efficacy of pooled microbiotherapy products to corresponding single donor-derived products. We demonstrate that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria compared to single donor-derived products. We further reveal that pooled products decreased Salmonella and Clostridioides difficile pathogenicity in mice, while single donor-derived product efficacy was variable, with some products failing to control disease progression. Altogether, these findings support the development of pooled microbiotherapies to overcome donor-dependent treatment efficacy.

Existing and Future Strategies to Manipulate the Gut Microbiota With Diet as a Potential Adjuvant Treatment for Psychiatric Disorders

Nutrition and diet quality play key roles in preventing and slowing cognitive decline and have been linked to multiple brain disorders. This review compiles available evidence from preclinical studies and clinical trials on the impact of nutrition and interventions regarding major psychiatric conditions and some neurological disorders. We emphasize the potential role of diet-related microbiome alterations in these effects and highlight commonalities between various brain disorders related to the microbiome. Despite numerous studies shedding light on these findings, there are still gaps in our understanding due to the limited availability of definitive human trial data firmly establishing a causal link between a specific diet and microbially mediated brain functions and symptoms. The positive impact of certain diets on the microbiome and cognitive function is frequently ascribed with the anti-inflammatory effects of certain microbial metabolites or a reduction of proinflammatory microbial products. We also critically review recent research on pro- and prebiotics and nondietary interventions, particularly fecal microbiota transplantation. The recent focus on diet in relation to brain disorders could lead to improved treatment outcomes with combined dietary, pharmacological, and behavioral interventions.

Multi-omics analysis of fecal microbiota transplantation's impact on functional constipation and comorbid depression and anxiety

BACKGROUND

Depression and anxiety are common comorbid diseases of constipation. Fecal microbiota transplantation (FMT) significantly relieves gastrointestinal-related symptoms, but its impact on psychiatric symptoms remains uncharted.

METHODS

We collected fecal and serum samples before and after FMT from 4 functional constipation patients with psychiatric symptoms and corresponding donor stool samples. We categorized the samples into two groups: before FMT (Fb) and after FMT (Fa). Parameters associated with constipation, depression, and anxiety symptoms were evaluated. Metagenomics and targeted neurotransmitter metabolomics were performed to investigate the gut microbiota and metabolites. 5-hydroxytryptamine (5-HT) biosynthesis was detected in patients' fecal supernatants exposed to the QGP-1 cell model in vitro.

RESULTS

Our study demonstrated that patient's constipation, depression, and anxiety were improved after FMT intervention. At the genus level, relative abundance of g_Bacteroides and g_Klebsiella decreased in the Fa group, while g_Lactobacillus, and g_Selenomonas content increased in the same group. These observations suggest a potential involvement of these genera in the pathogenesis of constipation with psychiatric symptoms. Metabolomics analysis showed that FMT intervention decreased serum 5-HT levels. Additionally, we found that species, including s_Klebsiella sp. 1_1_55, s_Odoribacter splanchnicus, and s_Ruminococcus gnavus CAG:126, were positively correlated with 5-HT levels. In contrast, s_Acetobacterium bakii, s_Enterococcus hermanniensis, s_Prevotella falsenii, s_Propionispira arboris, s_Schwartzia succinivorans, s_Selenomonas artemidis, and s_Selenomonas sp. FC4001 were negatively correlated with 5-HT levels. Furthermore, we observed that patients' fecal supernatants increased 5-HT biosynthesis in QGP-1 cells.

CONCLUSION

FMT can relieve patients' constipation, depression, and anxiety symptoms by reshaping gut microbiota. The 5-HT level was associated with an altered abundance of specific bacteria or metabolites. This study provides specific evidence for FMT intervention in constipation patients with psychiatric symptoms.

Promising new pharmacological targets for depression: The search for efficacy

Pharmacological treatment of major depressive disorder (MDD) still relies on the use of serotonergic drugs, despite their limited efficacy. A few mechanistically new drugs have been developed in recent years, but many fail in clinical trials. Several hypotheses have been proposed to explain MDD pathophysiology, indicating that physiological processes such as neuroplasticity, circadian rhythms, and metabolism are potential targets. Here, we review the current state of pharmacological treatments for MDD, as well as the preclinical and clinical evidence for an antidepressant effect of molecules that target non-serotonergic systems. We offer some insights into the challenges facing the development of new antidepressant drugs, and the prospect of finding more effectiveness for each target discussed.

Fecal microbiota transplantation for treatment of irritable bowel syndrome: Current advances and future perspectives

Irritable bowel syndrome (IBS) is a kind of functional gastroin-testinal disorder, characterized by recurrent abdominal pain and altered bowel habits. IBS adversely affects the quality of life of patients for the lack of effective treatment. The etiology of IBS remains poorly known. Previous studies suggested a possible role of gut dysbiosis in IBS pathogenesis. Fecal microbiota transplantation (FMT), which aims to reverse the gut dysbiosis, is a promising strategy in IBS management. In this review, we summarize the role of the gut microbiota in IBS pathogenesis from different aspects. We also review recent studies on efficacy evaluation of FMT in IBS. Besides, we discuss factors affecting the efficacy of FMT, hoping to provide a reference for future IBS treatment strategies targeting the gut microbiota.

[Fecal Microbiota Transplants in the Context of (Child and Adolescent) Psychiatric Disorders]

Fecal Microbiota Transplants in the Context of (Child and Adolescent) Psychiatric Disorders Abstract: There has recently been a significant increase in interest in gut microbiota and its interaction with the brain (gut-brain axis). Not only are the findings of microbiome research interesting for basic scientists, they also offer relevant insights for clinical practice. A causal relationship between gut microbiome and various somatic diseases such as diabetes mellitus, inflammatory bowel diseases, and obesity as well as psychiatric diseases such as major depression, anxiety disorders, and eating disorders seems plausible. To study the causal relationship of intestinal bacteria with individual phenotypes, researchers apply so-called stool transplantations (fecal microbiota transplantations) in the preclinical context. For this purpose, they transfer microbiota samples from patients into laboratory animals to observe possible changes in phenotype. In the clinical context, fecal microbiota transplantation is already being used with therapeutic intentions for selected diseases, for example, recurrent infections with Clostridioides difficile or inflammatory bowel diseases; they have already become part of the official clinical guidelines for C. difficile. For many other diseases, however, including mental illnesses, the potential of using fecal transplantations for therapeutic purposes is still being explored. Previous findings suggest that the intestinal microbiome, particularly fecal microbiota transplantations, represent a promising starting point for new therapeutic approaches.

Is there a role for microbiome-based approach in common variable immunodeficiency?

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by low levels of serum immunoglobulins and increased susceptibility to infections, autoimmune disorders and cancer. CVID embraces a plethora of heterogeneous manifestations linked to complex immune dysregulation. While CVID is thought to be due to genetic defects, the exact cause of this immune disorder is unknown in the large majority of cases. Compelling evidences support a linkage between the gut microbiome and the CVID pathogenesis, therefore a potential for microbiome-based treatments to be a therapeutic pathway for this disorder. Here we discuss the potential of treating CVID patients by developing a gut microbiome-based personalized approach, including diet, prebiotics, probiotics, postbiotics and fecal microbiota transplantation. We also highlight the need for a better understanding of microbiota-host interactions in CVID patients to prime the development of improved preventive strategies and specific therapeutic targets.

CE: Current and Emerging Applications of Fecal Microbiota Transplantation

ABSTRACT

Fecal microbiota transplantation (FMT) is a life-changing treatment for people with recurrent Clostridioides difficile infection (rCDI). Frequently acquired in the hospital, CDI can cause serious gastrointestinal symptoms, including persistent watery diarrhea, abdominal pain, and severe dehydration. Antibiotics, the primary treatment, can unfortunately disrupt the gut microbiome and lead to antimicrobial resistance. FMT involves introducing stool from a healthy donor into the affected recipient to strengthen their compromised microbiome. Individuals receiving this treatment have reported remarkable improvement in clinical outcomes and quality of life. In addition to a discussion of rCDI within the context of the gastrointestinal microbiome, this article provides an overview of the FMT procedure, discusses nursing management of individuals undergoing FMT, and highlights emerging applications beyond rCDI. A case scenario is also provided to illustrate a typical trajectory for a patient undergoing FMT.

Fecal microbiota transplantation for the treatment of irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is the most prevalent gastrointestinal disorder in developed countries and reduces patients’ quality of life, hinders their ability to work, and increases health care costs. A growing number of trials have demonstrated an aberrant gut microbiota composition in IBS, also known as ‘gut dysbiosis’. Fecal microbiota transplantation (FMT) has been suggested as a treatment for IBS.

AIM

To assess the efficacy and safety of FMT for the treatment of IBS.

METHODS

We searched Cochrane Central, MEDLINE, EMBASE and Web of Science up to 24 October 2022 for randomised controlled trials (RCTs) investigating the effectiveness of FMT compared to placebo (including autologous FMT) in treating IBS. The primary outcome was the number of patients with improvements of symptoms measured using a validated, global IBS symptoms score. Secondary outcomes were changes in quality-of-life scores, non-serious and serious adverse events. Risk ratios (RR) and corresponding 95%CI were calculated for dichotomous outcomes, as were the mean differences (MD) and 95%CI for continuous outcomes. The Cochrane risk of bias tool was used to assess the quality of the trials. GRADE criteria were used to assess the overall quality of the evidence.

RESULTS

Eight RCTs (484 participants) were included in the review. FMT resulted in no significant benefit in IBS symptoms three months after treatment compared to placebo (RR 1.19, 95%CI: 0.68-2.10). Adverse events were reported in 97 participants in the FMT group and in 45 participants in the placebo group (RR 1.17, 95%CI: 0.63-2.15). One serious adverse event occurred in the FMT group and two in the placebo group (RR 0.42, 95%CI: 0.07-2.60). Endoscopic FMT delivery resulted in a significant improvement in symptoms, while capsules did not. FMT did not improve the quality of life of IBS patients but, instead, appeared to reduce it, albeit non significantly (MD -6.30, 95%CI: -13.39-0.79). The overall quality of the evidence was low due to moderate-high inconsistency, the small number of patients in the studies, and imprecision.

CONCLUSION

We found insufficient evidence to support or refute the use of FMT for IBS. Larger trials are needed.

Gut Microbiome-Brain Alliance: A Landscape View into Mental and Gastrointestinal Health and Disorders

Gut microbiota includes a vast collection of microorganisms residing within the gastrointestinal tract. It is broadly recognized that the gut and brain are in constant bidirectional communication, of which gut microbiota and its metabolic production are a major component, and form the so-called gut microbiome-brain axis. Disturbances of microbiota homeostasis caused by imbalance in their functional composition and metabolic activities, known as dysbiosis, cause dysregulation of these pathways and trigger changes in the blood-brain barrier permeability, thereby causing pathological malfunctions, including neurological and functional gastrointestinal disorders. In turn, the brain can affect the structure and function of gut microbiota through the autonomic nervous system by regulating gut motility, intestinal transit and secretion, and gut permeability. Here, we examine data from the CAS Content Collection, the largest collection of published scientific information, and analyze the publication landscape of recent research. We review the advances in knowledge related to the human gut microbiome, its complexity and functionality, its communication with the central nervous system, and the effect of the gut microbiome-brain axis on mental and gut health. We discuss correlations between gut microbiota composition and various diseases, specifically gastrointestinal and mental disorders. We also explore gut microbiota metabolites with regard to their impact on the brain and gut function and associated diseases. Finally, we assess clinical applications of gut-microbiota-related substances and metabolites with their development pipelines. We hope this review can serve as a useful resource in understanding the current knowledge on this emerging field in an effort to further solving of the remaining challenges and fulfilling its potential.

Key determinants of success in fecal microbiota transplantation: From microbiome to clinic

Fecal microbiota transplantation (FMT) has achieved satisfactory results in preventing the recurrence of Clostridioides difficile infection, but these positive outcomes have only been partially replicated in other diseases. Several factors influence FMT success, including those related to donors and recipients (including diversity and specific composition of the gut microbiome, immune system, and host genetics) as well as to working protocols (fecal amount and number of infusions, route of delivery, and adjuvant treatments). Moreover, initial evidence suggests that the clinical success of FMT may be related to the degree of donor microbial engraftment. The application of cutting-edge technologies for microbiome assessment, along with changes in the current vision of fecal transplants, are expected to improve FMT protocols and outcomes. Here, we review the key determinants of FMT success and insights and strategies that will enable a close integration of lab-based and clinical approaches for increasing FMT success.

Bifidobacterium: a probiotic for the prevention and treatment of depression

Depression is a common psychological disease, which has become one of the main factors affecting human health. It has a serious impact on individuals, families, and society. With the prevalence of COVID-19, the incidence of depression has further increased worldwide. It has been confirmed that probiotics play a role in preventing and treating depression. Especially, Bifidobacterium is the most widely used probiotic and has positive effects on the treatment of depression. The mechanisms underlying its antidepressant effects might include anti-inflammation and regulation of tryptophan metabolism, 5-hydroxytryptamine synthesis, and the hypothalamus-pituitary-adrenal axis. In this mini-review, the relationship between Bifidobacterium and depression was summarized. It is hoped that Bifidobacterium-related preparations would play a positive role in the prevention and treatment of depression in the future.

Gut Bacterial Dysbiosis in Irritable Bowel Syndrome: a Case-Control Study and a Cross-Cohort Analysis Using Publicly Available Data Sets

Research on the gut microbiota in irritable bowel syndrome (IBS) shows discordant results due to inconsistent study designs or small sample sizes. This study aimed to characterize how gut microbiota in IBS patients differs from that in healthy controls by performing a case-control study and cross- and mega-cohort analysis. Multiple publicly shared data sets were examined by using a unified analytical approach. We performed 16S rRNA gene (V3-4) sequencing and taxonomic profiling of the gut bacterial communities. Fecal samples from children with IBS (n = 19) and age-matched healthy controls (n = 24) were used. Next, we analyzed 10 separate data sets using a unified data-processing and analytical approach. In total, 567 IBS patients and 487 healthy controls were examined. In our data sets, no significant differences existed in stool α-diversity between IBS patients and healthy controls. After combining all the data sets using a unified data-processing method, we found significantly lower α-diversity in IBS patients than in healthy controls. In addition, the relative abundance of 21 bacterial species differed between the IBS patients and healthy participants. Although the causal relationship is uncertain, gut bacterial dysbiosis is associated with IBS. Further functional studies are needed to assess whether the change in gut microorganisms contributes to the development of IBS. IMPORTANCE Research on the gut bacteria in irritable bowel syndrome (IBS) shows discordant results due to inconsistent study designs or small sample sizes. To overcome these issues, we analyzed microbiota of 567 IBS patients and 487 healthy people from 10 shared data sets using a unified method. We demonstrated that gut bacteria are less diverse in IBS patients than in healthy people. In addition, the abundance of 21 bacterial species is different between the two groups. Altered bacterial balance, called dysbiosis, has been reported in several disease states. Although the causal relationship is uncertain, gut bacterial dysbiosis also seems to be associated with IBS.

Fecal microbiota transplantation in non-communicable diseases: Recent advances and protocols

Fecal microbiota transplant (FMT) is a therapeutic method that aims to restore normal gut microbial composition in recipients. Currently, FMT is approved in the USA to treat recurrent and refractory Clostridioides difficile infection and has been shown to have great efficacy. As such, significant research has been directed toward understanding the potential role of FMT in other conditions associated with gut microbiota dysbiosis such as obesity, type 2 diabetes mellitus, metabolic syndrome, neuropsychiatric disorders, inflammatory bowel disease, irritable bowel syndrome, decompensated cirrhosis, cancers and graft-versus-host disease. This review examines current updates and efficacy of FMT in treating conditions other than Clostridioides difficile infection. Further, protocols for administration of FMT are also discussed including storage of fecal samples in stool banks, inclusion/exclusion criteria for donors, fecal sample preparation and methods of treatment administration. Overall, understanding the mechanisms by which FMT can manipulate gut microbiota to provide therapeutic benefit as well as identifying potential adverse effects is an important step in clarifying its long-term safety and efficacy in treating multiple conditions in the future.

Ischemic stroke and concomitant gastrointestinal complications- a fatal combination for patient recovery

Stroke is primarily a neurodegenerative disease but can also severely impact the functions of other vital organs and deteriorate disease outcomes. A malfunction of the gastrointestinal tract (GIT), commonly observed in stroke patients, is often characterized by severe bowel obstruction, intestinal microbiota changes and inflammation. Over-activated immune cells after stroke are the major contributors to endorse intestinal inflammation and may induce damage to single-layer epithelial cell barriers. The post-stroke leakage of intestinal barriers may allow the translocation and dissemination of resident microflora to systemic organs and cause sepsis. This overshooting systemic immune reaction fuels ongoing inflammation in the degenerating brain and slows recovery. Currently, the therapeutic options to treat these GIT-associated anomalies are very limited and further research is required to develop novel treatments. In this mini-review, we first discuss the current knowledge from clinical studies and experimental stroke models that provide strong evidence of the existence of post-stroke GIT complications. Then, we review the literature regarding novel therapeutic approaches that might help to maintain GIT homeostasis and improve neurological outcomes in stroke patients.

An observational investigation of the faical microbiota and metabonome of gastrostomy fed children, on blended and formula diets

Gastrostomy fed children traditionally have a Formulae diet (FD), which fulfills nutritional requirements; however, many families are adopting Blended diets (BD), which are what the whole family would eat. We undertook an observational investigation of the colonic microbiota and metabonome in a small group of gastrostomy fed children, who were either on an FD or BD, and compared, where possible to their siblings (17 FD, 28 BD, 19 HS). There was no increase in complications in tube blockage or infection rates, but a significant improvement in the prevalence of bowel problems, a reduction in medication and an increase in quality of life. Metataxonomic analysis showed that the FD group was significantly different to the Sibling group, and that families did not cluster together. Whole sample metabonomics showed no differences between groups; however, univariate analysis of biologically important metabolites did differ. Changing to a BD resulted in no increase in complications or risks, but improved the overall quality of life for the children and families.

Pre-Antibiotic Treatment Followed by Prolonged Repeated Faecal Microbiota Transplantation Improves Symptoms and Quality of Life in Patients with Irritable Bowel Syndrome: An Observational Australian Clinical Experience

Background. The use of faecal microbiota transplantation (FMT) in irritable bowel syndrome (IBS) has frequently failed to induce long-term symptomatic improvement. The use of multiple FMT infusions is one proposed mechanism through which the efficacy of FMT can be amplified. Aims. To evaluate the safety and efficacy of a novel six-month FMT treatment protocol in IBS. Methods. Patients diagnosed with IBS confirmed by Rome IV Criteria were recruited for single-centre, single-arm, prospective clinical observational study. Participants received one colonoscopically delivered FMT followed by 36 rectal enemas across a six-month period. Validated abdominal symptoms and Short-Form (SF-36) Quality of Life (QOL) questionnaires were collected at baseline, week-12, week-24, and week-56, respectively. Wilcoxon matched-pairs signed-rank tests were conducted to compare differences in abdominal symptom and SF-36 QOL scores over the follow-up timepoints. Statistical significance was set at 5%. Results. Sixty participants diagnosed with IBS [IBS-constipation ( $n=27$ ), IBS-diarrhoea ( $n=18$ ), and IBS-mixed ( $n=15$ )] received the six-month FMT treatment. IBS symptom severity reduction was achieved in up to 61% of respondents at week-12, 64% of respondents at week-24, and maintained in up to 75% of respondents at week-52. Long-term reduction in symptom severity was associated with an increase in QOL, achieved in up to 64% of respondents at week-52 when compared to baseline. Adverse events were experienced in 28% of participants, though they were both transient and mild in nature. Conclusions. Six-month sustained FMT appears to be both safe and effective in the short- and long-term alleviation of IBS associated symptoms as well as improving participant QOL.

Antitumor effects of fecal microbiota transplantation: Implications for microbiome modulation in cancer treatment

Fecal microbiome transplantation (FMT) from healthy donors is one of the techniques for restoration of the dysbiotic gut, which is increasingly being used to treat various diseases. Notably, mounting evidence in recent years revealed that FMT has made a breakthrough in the oncology treatment area, especially by improving immunotherapy efficacy to achieve antitumor effects. However, the mechanism of FMT in enhancing antitumor effects of immune checkpoint blockers (ICBs) has not yet been fully elucidated. This review systematically summarizes the role of microbes and their metabolites in the regulation of tumor immunity. We highlight the mechanism of action of FMT in the treatment of refractory tumors as well as in improving the efficacy of immunotherapy. Furthermore, we summarize ongoing clinical trials combining FMT with immunotherapy and further focus on refined protocols for the practice of FMT in cancer treatment, which could guide future directions and priorities of FMT scientific development.

Efficacy and safety of fecal microbiota transplant in irritable bowel syndrome: An update based on meta-analysis of randomized control trials

Background and Aims

Fecal microbiota transfer (FMT) is a potential treatment for irritable bowel syndrome (IBS). Several randomized trials have tested FMT effects using different routes of administration, doses, and sample sizes. We aim to assess the overall efficacy of FMT for IBS patients and the safety of the intervention.

Methods

We systematically searched four databases for randomized control trials that studied the efficacy and safety of FMT in IBS patients.

Results

We included 8 randomized trials (472 patients) that compared FMT with placebo in IBS patients. Pooled results showed no statistically significant difference between FMT and control groups in the overall change in IBS symptom severity (IBS-SSS) at 1 month (p = 0.94), 3/4 months (p = 0.82), and at the end of trials (p = 0.67). No significant difference in the total number of respondents between the FMT and control groups (risk ratios = 1.84, [95% confidence interval (CI) = 0.82-2.65], p = 0.19). Although the oral route of administration showed a significant difference in the number of respondents (p = 0.004), there was no statistically significant difference in the IBS-SSS when subgrouping the oral route of administration (mean difference = 47.57, [95% CI = -8.74-103.87], p = 0.10).

Conclusion

FMT is not an effective treatment to relieve all the symptoms of IBS. Even in the groups that showed relatively significant improvement after FMT, the effect was proven to wear off over time and the re-administration carries a low success rate. Future research should consider different bacterial-based interventions such as probiotics or specific antibiotics.

Studies on irritable bowel syndrome associated with anxiety or depression in the last 20 years: A bibliometric analysis

Irritable bowel syndrome (IBS) associated with anxiety or depression is ubiquitous in clinical practice, and multiple related articles have been published. However, studies that utilize bibliometric analyses to address this topic are rare. In our study, we aimed to reveal research trends in IBS with anxiety or depression. Publications on IBS in relation to anxiety or depression in the last 20 years were obtained from the Web of Science Core Collection (WoSCC). CiteSpace software (5.8.R3) and GraphPad Prism 8 were used to perform bibliometric analysis of authors, countries, institutions, journals, keywords, and references involved in this topic. A total of 2,562 publications from 716 academic journals were included in this study. The majority of publications (n = 833, 32.51%) were from the USA, and the University of California, Los Angeles, contributed the most publications (n = 97, 3.79%). Active cooperations among countries and institutions were observed. Neurogastroenterology and Motility [impact factor (IF) 2020 = 3.598] published the most papers (170 publications, 6.64%), followed by Alimentary Pharmacology Therapeutics (IF 2020 = 8.171; 88 publications; 3.44%). The literatures related to IBS and anxiety or depression were primarily published in journals related to medicine/medical/clinical, neurology/sports/ophthalmology, and molecular/biology/immunology. Cryan JF and Drossman DA, with the largest number of articles (84 publications) and citations (917 citations), respectively, were considered as the most influential authors in this field. A total of 336 co-cited references were divided into 17 clusters, and #1 fecal microbiota transplantation contained most of the documents published in recent years. Moreover, the keyword "psychosocial factor" had the largest burst strength of 13.52, followed by the keyword "gut microbiota" with a burst strength of 11.71. This study shows the research performance of IBS related to anxiety or depression from 2002 to 2021 and helps researchers master the trend in this field, which should receive more attention.

Feeding Our Microbiota: Stimulation of the Immune/Semiochemical System and the Potential Amelioration of Non-Communicable Diseases

Non-communicable diseases are those conditions to which causative infectious agents cannot readily be assigned. It is increasingly likely that at least some of these conditions are due to the breakdown of the previously mutualistic intestinal microbiota under the influence of a polluted, biocide-rich, environment. Following the mid-20th century African studies of Denis Burkitt, the environmental cause of conditions such as obesity has been ascribed to the absence of sufficient fibre in the modern diet, however in itself that is insufficient to explain the parallel rise of problems with both the immune system and of mental health. Conversely, Burkitt himself noted that the Maasai, a cattle herding people, remained healthy even with their relatively low intake of dietary fibre. Interestingly, however, Burkitt also emphasised that levels of non-communicable disease within a population rose as faecal weight decreased significantly, to about one third of the levels found in healthy populations. Accordingly, a more cogent explanation for all the available facts is that the fully functioning, adequately diverse microbiome, communicating through what has been termed the microbiota-gut-brain axis, helps to control the passage of food through the digestive tract to provide itself with the nutrition it needs. The method of communication is via the production of semiochemicals, interkingdom signalling molecules, potentially including dopamine. In turn, the microbiome aids the immune system of both adult and, most importantly, the neonate. In this article we consider the role of probiotics and prebiotics, including fermented foods and dietary fibre, in the stimulation of the immune system and of semiochemical production in the gut lumen. Finally, we reprise our suggestion of an ingestible sensor, calibrated to the detection of such semiochemicals, to assess both the effectiveness of individual microbiomes and methods of amelioration of the associated non-communicable diseases.

Fecal Microbiota Transplantation as New Therapeutic Avenue for Human Diseases

The human body is home to a variety of micro-organisms. Most of these microbial communities reside in the gut and are referred to as gut microbiota. Over the last decades, compelling evidence showed that a number of human pathologies are associated with microbiota dysbiosis, thereby suggesting that the reinstatement of physiological microflora balance and composition might ameliorate the clinical symptoms. Among possible microbiota-targeted interventions, pre/pro-biotics supplementations were shown to provide effective results, but the main limitation remains in the limited microbial species available as probiotics. Differently, fecal microbiota transplantation involves the transplantation of a solution of fecal matter from a donor into the intestinal tract of a recipient in order to directly change the recipient's gut microbial composition aiming to confer a health benefit. Firstly used in the 4th century in traditional Chinese medicine, nowadays, it has been exploited so far to treat recurrent Clostridioides difficile infections, but accumulating data coming from a number of clinical trials clearly indicate that fecal microbiota transplantation may also carry the therapeutic potential for a number of other conditions ranging from gastrointestinal to liver diseases, from cancer to inflammatory, infectious, autoimmune diseases and brain disorders, obesity, and metabolic syndrome. In this review, we will summarize the commonly used preparation and delivery methods, comprehensively review the evidence obtained in clinical trials in different human conditions and discuss the variability in the results and the pivotal importance of donor selection. The final aim is to stimulate discussion and open new therapeutic perspectives among experts in the use of fecal microbiota transplantation not only in Clostridioides difficile infection but as one of the first strategies to be used to ameliorate a number of human conditions.

Fecal microbiota transplantation in the treatment of irritable bowel syndrome: a single-center prospective study in Japan

Background

Fecal microbiota transplantation (FMT) is a potential treatment for irritable bowel syndrome (IBS), but its efficacy in Japanese IBS patients is unknown. This study aimed to evaluate the efficacy, side effects, and microbiome changes following FMT in Japanese IBS patients.

Methods

Seventeen Japanese patients with refractory IBS received FMT (4 donors) under colonoscopy. Responders were defined by an improvement in the IBS severity index (IBS-SI) of 50 points or more after 12 weeks. We evaluated the IBS-SI and Bristol Stool Form Scale (BSFS) and compared the diversity and microbiome before and 12 weeks after FMT. For the microbiome, we analyzed the V3–V4 region of the 16S rRNA gene.

Results

IBS-SI decreased an average of 115.58 points after 12 weeks, and 10 patients (58.8%) were considered responders. Eight patients with diarrhea (66.7%) and three patients with constipation (60.0%) showed improvement in the BSFS. Two patients complained of mild abdominal pain, but there were no cases with severe side-effects. α-diversity was increased only in the responder group (p = 0.017). Patients who closely paralleled the donor microbiome had a higher rate of IBS-SI improvement. The relative abundance of Neisseria and Akkermansia increased and Desulfovibrio and Delftia were decreased in the responder group after FMT.

Conclusions

Following FMT, about 60% of Japanese patients with IBS showed improvement in both the IBS-SI and BSFS, without severe side effects. Increased α-diversity and similarity to the donor microbiome after FMT may be associated with better treatment effects.

Trial registration: This study was registered in the University Hospital Medical Information Network Clinical Trial Registration (UMIN000026363). Registered 31 May 2017, https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000026363. The study was registered prospectively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02408-5.

An Updated Narrative Mini-Review on the Microbiota Changes in Antenatal and Post-Partum Depression

Background: Antenatal depression (AND) and post-partum depression (PPD) are long-term debilitating psychiatric disorders that significantly influence the composition of the gut flora of mothers and infants that starts from the intrauterine life. Not only does bacterial ratio shift impact the immune system, but it also increases the risk of potentially life-threatening disorders. Material and Methods: Therefore, we conducted a narrative mini-review aiming to gather all evidence published between 2018–2022 regarding microflora changes in all three stages of pregnancy. Results: We initially identified 47 potentially eligible studies, from which only 7 strictly report translocations; 3 were conducted on rodent models and 4 on human patients. The remaining studies were divided based on their topic, precisely focused on how probiotics, breastfeeding, diet, antidepressants, exogenous stressors, and plant-derived compounds modulate in a bidirectional way upon behavior and microbiota. Almost imperatively, dysbacteriosis cause cognitive impairments, reflected by abnormal temperament and personality traits that last up until 2 years old. Thankfully, a distinct technique that involves fecal matter transfer between individuals has been perfected over the years and was successfully translated into clinical practice. It proved to be a reliable approach in diminishing functional non- and gastrointestinal deficiencies, but a clear link between depressive women’s gastrointestinal/vaginal microbiota and clinical outcomes following reproductive procedures is yet to be established. Another gut-dysbiosis-driving factor is antibiotics, known for their potential to trigger inflammation. Fortunately, the studies conducted on mice that lack microbiota offer, without a shadow of a doubt, insight. Conclusions: It can be concluded that the microbiota is a powerful organ, and its optimum functionality is crucial, likely being the missing puzzle piece in the etiopathogenesis of psychiatric disorders.

Microbiome–Gut Dissociation in the Neonate: Obesity and Coeliac Disease as Examples of Microbiome Function Deficiency Disorder

The purpose of this article is to provide a direction for translational research based on an analysis of the nature of complex, immune-related conditions such as obesity and coeliac disease. In essence, it seems that the prevalence of these non-communicable diseases is related to the degradation of the microbiome during the industrialisation of society, and that their nature can be used to infer the functions of the “pre-industrial” microbiome. Based on this analysis, the key point is the necessity for the fully functioning microbiome, acting alongside the parental genetic inheritance of the child, to be in place immediately after birth. In our view, this is achieved by the seemingly accidental process of maternal microbial inheritance during normal birth. Note, however, that this is not possible if the microbiome of the mother is itself degraded following previous problems. Under these conditions the health of a child may be affected from the moment of birth, although, with the exception of atopic diseases, such as eczema and food allergy, the consequences may not become apparent until late childhood or as an adult. In this way, this microbiome function deficiency hypothesis incorporates the epidemiological observations of David Strachan and David Barker in that their onset can be traced to early childhood. Coeliac disease has been chosen as an illustrative example of a multifactorial disorder due to the fact that, in addition to a series of immune system manifestations and a potential problem with food absorption, there is also a significant psychological component. Finally, it is worth noting that an ingestible sensor calibrated to the detection of interkingdom communication molecules (semiochemicals) within the intestine may offer a practical way of assessment and, perhaps, amelioration of at least some of the consequences of non-communicable disease.

Donor-dependent fecal microbiota transplantation efficacy against necrotizing enterocolitis in preterm pigs

The development of necrotizing enterocolitis (NEC), a life-threatening inflammatory bowel disease affecting preterm infants, is connected with gut microbiota dysbiosis. Using preterm piglets as a model for preterm infants we recently showed that fecal microbiota transplantation (FMT) from healthy suckling piglet donors to newborn preterm piglets decreased the NEC risk. However, in a follow-up study using donor stool from piglets recruited from another farm, this finding could not be replicated. This allowed us to study donor-recipient microbiota dynamics in a controlled model system with a clear difference in NEC phenotype. Preterm piglets (n = 38) were randomly allocated to receive control saline (CON), or rectal FMT using either the ineffective (FMT1) or the effective donor stool (FMT2). All animals were followed for four days before necropsy and gut pathological evaluation. Donor and recipient colonic gut microbiota (GM) were analyzed by 16 S rRNA gene amplicon sequencing and shotgun metagenomics. As expected, only FMT2 recipients were protected against NEC. Both FMT groups had shifted GM composition relative to CON, but FMT2 recipients had a higher lactobacilli relative abundance compared to FMT1. Limosilactobacillus reuteri and Lactobacillus crispatus strains of FMT recipients showed high phylogenetic similarity with their respective donors, indicating engraftment. Moreover, the FMT2 group had a higher lactobacilli replication rate and harbored specific glycosaminoglycan-degrading Bacteroides. In conclusion, subtle species-level donor differences translate to major changes in engraftment dynamics and the ability to prevent NEC. This could have implications for proper donor selection in future FMT trials for NEC prevention.

Gut microbial β-glucuronidases regulate host luminal proteases and are depleted in irritable bowel syndrome

Intestinal proteases mediate digestion and immune signaling, while increased gut proteolytic activity disrupts the intestinal barrier and generates visceral hypersensitivity, which in common in irritable bowel syndrome (IBS). However, the mechanisms controlling protease function are unclear. Here we show that members of the gut microbiota suppress intestinal proteolytic activity through production of unconjugated bilirubin. This occurs via microbial β-glucuronidase-mediated conversion of bilirubin conjugates. Metagenomic analysis of fecal samples from patients with post-infection IBS (n=52) revealed an altered gut microbiota composition, in particular a reduction in Alistipes taxa, and high gut proteolytic activity driven by specific host serine proteases compared to controls. Germ-free mice showed 10-fold higher proteolytic activity compared with conventional mice. Colonization with microbiota from high proteolytic activity IBS patients failed to suppress proteolytic activity in germ-free mice, but suppression of proteolytic activity was achieved with colonization using microbiota from healthy donors. High proteolytic activity mice had higher intestinal permeability, a higher relative abundance of Bacteroides and a reduction in Alistipes taxa compared with low proteolytic activity mice. High proteolytic activity IBS patients had lower fecal β-glucuronidase activity and end-products of bilirubin deconjugation. Mice treated with unconjugated bilirubin and β-glucuronidase overexpressing E. coli, which significantly reduced proteolytic activity, while inhibitors of microbial β-glucuronidases increased proteolytic activity. Together, these data define a disease-relevant mechanism of host-microbial interaction that maintains protease homeostasis in the gut.

Bile acid-gut microbiota crosstalk in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction with an increasing prevalence, and its precise aetiology remains unclear. Gut microbiota dysbiosis has been found to be associated with IBS pathogenesis. In addition, a high incidence of bile acid diarrhoea and disturbed bile acid metabolism has been observed in IBS patients. The abundant microorganisms inhabited in human gut have essential functions in bile acid biotransformation, and can immensely affect the size and constitution of bile acid pool. Meanwhile, the alterations of bile acid profile can inversely interfere with the gut microbiota. This review discussed the role of intricate correlations between bile acids and gut microbiota in IBS pathogenesis and delineated the possible molecular mechanisms, mainly the signalling induced by farnesoid X receptor and transmembrane G protein-coupled receptor 5. Besides, some biomarkers for identifying bile acid diarrhoea in IBS population were listed, assisting the diagnosis and classification of IBS. Moreover, it also assessed some therapeutic strategies for IBS that regulate the bile acid-gut microbiota axis, such as dietary modulation, probiotics/prebiotics, faecal microbiota transplantation, and antibiotics. Collectively, this article illustrated the relationship between bile acids and gut microbiota in IBS pathophysiology and might offer some novel therapeutic options for IBS.

Bi-Directionality of the Microbiota-Gut-Brain Axis in Patients With Functional Dyspepsia: Relevance of Psychotherapy and Probiotics

Functional dyspepsia is one of the most commonly diagnosed disorders of the gut-brain interaction worldwide. The precise pathogenesis of functional dyspepsia is complex and remains incompletely understood. Therefore, advances in the understanding of functional dyspepsia could change clinical practice. The aim of this review is to highlight the relevance of psychotherapy and probiotics in the context of the microbiota-gut-brain axis in the pathophysiology and especially in the treatment of functional dyspepsia. Therefore, studies which have been conducted to investigate the role of psychotherapy and probiotics in FD and the microbiota-gut-brain axis in the pathophysiology of functional dyspepsia were examined, and the outcomes of this research summarized. There might be a link between changes in the microbiome and functional dyspepsia. Even though, specific alterations in the microbiome that may be pathognomonic in functional dyspepsia remain unclear, the use of probiotics became a viable treatment option for patients with functional dyspepsia. Since mental illness also plays an important role in the pathophysiology of functional dyspepsia, psychotherapy is a useful treatment method, with additional study results indicating that psychotherapy may also shift the microbiome in a favorable direction. Moreover, other findings suggest that probiotics can be used not only to alleviate gastrointestinal symptoms in functional dyspepsia, but also to treat or even prevent mental disorders in these patients. In summary, in this review we highlight the bi-directionality of the microbiota-gut-brain axis in the pathophysiology of functional dyspepsia. Although there are multiple treatment approaches, the burden of disease in patients with functional dyspepsia is still enormous and a definitive therapy to cure this disease does not (yet) exist. Lastly, there is a lack of studies on the impact of dysbiosis, mental health and probiotics on pathophysiology and symptomatology in functional dyspepsia which should be investigated in future studies.

How Microbes Affect Depression: Underlying Mechanisms via the Gut-Brain Axis and the Modulating Role of Probiotics

Accumulating evidence suggests that the gut microbiome influences the brain functions and psychological state of its host via the gut-brain axis, and gut dysbiosis has been linked to several mental illnesses, including major depressive disorder (MDD). Animal experiments have shown that a depletion of the gut microbiota leads to behavioral changes, and is associated with pathological changes, including abnormal stress response and impaired adult neurogenesis. Short-chain fatty acids such as butyrate are known to contribute to the up-regulation of brain-derived neurotrophic factor (BDNF), and gut dysbiosis causes decreased levels of BDNF, which could affect neuronal development and synaptic plasticity. Increased gut permeability causes an influx of gut microbial components such as lipopolysaccharides, and the resultant systemic inflammation may lead to neuroinflammation in the central nervous system. In light of the fact that gut microbial factors contribute to the initiation and exacerbation of depressive symptoms, this review summarizes the current understanding of the molecular mechanisms involved in MDD onset, and discusses the therapeutic potential of probiotics, including butyrate-producing bacteria, which can mediate the microbiota-gut-brain axis.

Efficacy of Fecal Microbiota Transplantation in Irritable Bowel Syndrome Patients: An Updated Systematic Review and Meta-Analysis

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disease characterized by abdominal discomfort and bloating, diarrhea, and/or constipation. Fecal microbiota transplantation (FMT) is transferring the fecal bacteria and other microorganisms from a healthy person to another. We performed this systematic review and meta-analysis to assess the efficacy of FMT in treating IBS patients. We searched Scopus, PubMed, Cochrane, and Web of Science databases through June 2021 using relevant key words. We included 19 studies. Fecal microbiota transplantation was significantly superior to placebo in IBS quality of life after 4 weeks (mean difference [MD] = 7.47, 95% confidence interval [CI]: 2.05-12.89, p = .04), 12 weeks (MD = 9.99, 95% CI: 5.78-14.19, p < .00001), and 24 weeks (MD = 8.49, 95% CI: 0.47-16.52, p = .04), with no difference regarding IBS improvement symptoms and the IBS Severity Scoring System (SSS). Single-arm analysis revealed that the incidence of improvement of IBS symptoms was 57.8% (45.6%-69.9%) with reduction in IBS-SSS (MD = -74, 95% CI: -101.7 to -46.3). Fecal microbiota transplantation was superior to placebo in improving quality of life after 4, 12, and 24 weeks. Also, FMT improved IBS symptoms and reduced the IBS-SSS score. However, no deference was detected between FMT and placebo in IBS-SSS score and IBS symptoms improvement.

Is the Gut Microbiota a Neglected Aspect of Gut and Brain Disorders?

The gut microbiota is a quickly developing bacterial ecosystem with biodiversity. It is an adaptive immunity that varies with food intake, environmental conditions, and human habits, among other factors. Various external stimuli, such as drugs, can influence the gut microbial environment and lead to gut dysbiosis. Recently, gut dysbiosis has been identified as an important factor that leads to several diseases either by the released metabolites or by the gut neuronal connection. In brain disorders, gut dysbiosis is involved in neuropsychiatric manifestations, including autism spectrum disorder, anxiety, and depression by interfering with neurotransmitter homeostasis, and neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease by releasing abnormal metabolites from the gut. Gut dysbiosis has been documented in gut disorders, including inflammatory bowel disease or irritable bowel syndrome. Immune cells in the gut are modulated by external factors such as stress, diet, and drugs to produce inflammatory cytokines, including interleukins (IL-4, IL-6, IL-17, IL-23, etc.). Inflammatory cytokines lead to a cascade of events, which lead to various ailments in the bowel. Beneficial bacteria in the form of probiotics ameliorate the condition and have healthful effects in disease conditions. This warrants further research to identify newer therapeutic strategies for diseases that cannot be cured or are difficult to treat.

Hepatic encephalopathy and depression in chronic liver disease: is the common link systemic inflammation?

Hepatic encephalopathy and depression share a number of clinical features, such as cognitive impairment and psychomotor retardation, and are highly prevalent in patients with chronic liver disease. Both conditions signify a poor prognosis, carry an increased mortality and are major determinants of reduced health related quality of life. The pathophysiology of hepatic encephalopathy is complex. Whilst cerebral accumulation of ammonia is well-recognised as being central to the development of hepatic encephalopathy, systemic inflammation, which acts in synergy with hyperammonaemia, is emerging as a key driver in its development. The pro-inflammatory state is also widely documented in depression, and peripheral to brain communication occurs resulting in central inflammation, behavioural changes and depressive symptoms. Gut dysbiosis, with a similar reduction in beneficial bacteria, increase in pathogens and decreased bacterial diversity, has been observed in both hepatic encephalopathy and depression, and it may be that the resultant increased bacterial translocation causes their shared inflammatory pathophysiology. Whilst the literature on a positive association between hepatic encephalopathy and depression in cirrhosis remains to be substantiated, there is evolving evidence that treatment with psychobiotics may be of dual benefit, improving cognition and mood in cirrhosis.

Dietary Management for Faecal Microbiota Transplant: An International Survey of Clinical and Research Practice, Knowledge and Attitudes

Faecal microbiota transplantation (FMT) involves homogenisation and infusion of stool from a healthy, highly screened individual into the bowel of an unwell recipient. Dietary intake is an important modulator of the gut microbiota. Currently there are no clinical practice recommendations available to provide patients or stool donors with dietary advice for FMT. This study aimed to conduct an international survey to examine health professionals and researchers' attitudes, knowledge and current practice recommendations for diet in patients undergoing FMT. An online, cross-sectional, international survey comprising of health professionals and researchers managing patients undergoing treatment with FMT was conducted between July-October 2020. Purposeful and snowball sampling techniques were employed to identify eligible participants who were sent an email invitation and two email reminders with a link to participate in the electronic survey. The survey comprised 21 questions covering demographics, current practice, beliefs and future directions regarding FMT and diet. Closed responses were calculated as proportions of total responses. Open-ended responses were systematically categorised. Common themes were identified from recurring categories. Fifty-eight (M 60%) participants from 14 countries completed the survey. Participants were gastroenterologists (55%), with 1-5 years' experience working in FMT (48%) and treating up to ten patients with FMT per month (74%). Participants agreed that diet was an important consideration for FMT recipients and stool donors (both 71%), and that it would affect the outcomes of FMT. However, they did not feel confident in providing dietary advice to patients, nor that there was sufficient evidence to provide dietary advice and this was reflected in their practice. Future research must collect information on the dietary intake of patients and donors to better understand the relationship between diet and FMT outcomes. In clinical practice, promotion of healthy eating guidelines aligns with current practice and literature.

The prevalence of disorders of the gut-brain axis in type 2 diabetes mellitus patients with metabolic dysfunction-associated fatty liver disease: an observational study

BACKGROUND AND STUDY AIM

Disorders of the gut-brain axis (DGBI) and metabolic dysfunction-associated liver disease (MAFLD) are frequently diagnosed and exhibit pathophysiological similarities. This study aimed to estimate the prevalence of DGBI in type 2 diabetes mellitus (T2DM) patients with MAFLD.

PATIENTS AND METHODS

In this single center, observational study, in adults with T2DM demographics, diabetes-related parameters and liver tests were recorded. MAFLD was defined by the presence of hepatic steatosis on imaging. Functional dyspepsia (FD) and irritable bowel syndrome (IBS) were diagnosed based on Rome IV criteria. Quality of life (QOL), anxiety levels and depression levels were documented by validated questionnaires.

RESULTS

We included 77 patients, 44 with and 33 without steatosis. There were no significant differences in age, body mass index (BMI), waist circumference, HbA1c levels or metformin use between groups. IBS was significantly more prevalent in the liver steatosis group (9/44 vs. 2/33, p = .037), while a similar trend was observed for FD (9/35 vs. 2/31, p = .103). No differences were found in anxiety, depression and overall QOL. However, QOL subscales for health worry, food avoidance and social reaction were significantly higher in the liver steatosis group.

CONCLUSIONS

In otherwise comparable T2DM patients, DGBI, and especially IBS, are more prevalent in the presence of MAFLD. This difference could not be attributed to increased levels of anxiety or depression. Future research should target the underlying pathophysiological mechanisms.

Microbiome–Gut Dissociation: Investigating the Origins of Obesity

The reduction of excessive weight remains a major public health challenge, with control currently limited to a calorie reduction strategy. Currently, attempts are being made at revisiting the fibre hypothesis based on the African studies of Denis Burkitt, that the lack of dietary fibre in the modern diet was responsible for the occurrence of obesity and many of the other non-communicable diseases of what he called “Western civilization”. However, the dilemma is that Burkitt himself stressed that other peoples of his day, such as the Maasai, remained healthy without consuming such high fibre diets. Equally, the present obesity epidemic is accompanied by diseases of a malfunctioning immune system and of poor mental health that do not seem to be adequately explained simply by a deficiency of dietary fibre. Though unknown in Burkitt’s day, an increasing degradation of a mutualistic intestinal microbiome would offer a better fit to the observed epidemiology, especially if the microbiome is not effectively passed on from mother to child at birth. Taking the broader view, in this article we posit a view of the microbiome as a cofactor of mammalian evolution, in which a maternal microbial inheritance complements the parental genetic inheritance of the animal, both engaging epigenetic processes. As this would require the microbiome to be fully integrated with the animal as it develops into an adult, so we have a meaningful evolutionary role for the microbiome–gut–brain axis. By a failure to correctly establish a microbiome–gut interface, the inhibition of maternal microbial inheritance sets the scene for the future development of non-communicable disease: compromised immune system function on the one hand and dysfunctional gut–brain communication on the other. The basic principle is that the fully functioning, diverse, microbiome achieves interkingdom communication by the generation of messenger chemicals, semiochemicals. It is envisaged that the in situ detection of these as yet ill-defined chemical entities by means of an ingestible sensor would indicate the severity of disease and provide a guide as to its amelioration.

NIR light-responsive bacteria with live bio-glue coatings for precise colonization in the gut

Recombinant bacterial colonization plays an indispensable role in disease prevention, alleviation, and treatment. Successful application mainly depends on whether bacteria can efficiently spatiotemporally colonize the host gut. However, a primary limitation of existing methods is the lack of precise spatiotemporal regulation, resulting in uncontrolled methods that are less effective. Herein, we design upconversion microgels (UCMs) to convert near-infrared light (NIR) into blue light to activate recombinant light-responsive bacteria (Lresb) in vivo, where autocrine "functional cellular glues" made of adhesive proteins assist Lresb inefficiently colonizing the gut. The programmable engineering platform is further developed for the controlled and effective colonization of Escherichia coli Nissle 1917 (EcN) in the gut. The colonizing bacteria effectively alleviate DSS-induced colitis in mice. We anticipate that this approach could facilitate the clinical application of engineered microbial therapeutics to accurately and effectively regulate host health.

The role of microbiota-gut-brain axis in neuropsychiatric and neurological disorders

Emerging evidence indicates that the gut microbiota play a crucial role in the bidirectional communication between the gut and the brain suggesting that the gut microbes may shape neural development, modulate neurotransmission and affect behavior, and thereby contribute to the pathogenesis and/or progression of many neurodevelopmental, neuropsychiatric, and neurological conditions. This review summarizes recent data on the role of microbiota-gut-brain axis in the pathophysiology of neuropsychiatric and neurological disorders including depression, anxiety, schizophrenia, autism spectrum disorders, Parkinson's disease, migraine, and epilepsy. Also, the involvement of microbiota in gut disorders co-existing with neuropsychiatric conditions is highlighted. We discuss data from both in vivo preclinical experiments and clinical reports including: (1) studies in germ-free animals, (2) studies exploring the gut microbiota composition in animal models of diseases or in humans, (3) studies evaluating the effects of probiotic, prebiotic or antibiotic treatment as well as (4) the effects of fecal microbiota transplantation.

Mucosa-Associated Microbiota in Patients with Irritable Bowel Syndrome: A Comparison of Subtypes

BACKGROUND

Most studies on gut microbiome of irritable bowel syndrome (IBS) have focused on fecal microbiota, instead of mucosa-associated microbiota (MAM).

AIMS

The aim of this study wasto investigate the MAM in IBS patients including the difference in subtypes of IBS, namely, diarrhea-predominant IBS (IBS-D) and constipation-predominant IBS (IBS-C).

METHODS

Endoscopic brush samples were taken from terminal ileum and sigmoid colon of patients with IBS (17 IBS-D patients and 7 IBS-C patients) and 10 healthy controls. The MAM of samples was profiled by 16S rRNA gene amplicon sequencing. Potential changes in the MAM at the functional level were evaluated using PICRUSt software and the KEGG database.

RESULTS

There were no differences in MAM composition between terminal ileum and sigmoid colon according to β-diversity based on the UniFrac distance. In view of α-diversity, Shannon (evenness) but not Chao1 (richness) or observed operational taxonomic units tended to be lower in sigmoid colon MAM of IBS-C and IBS-D than the control group. The abundance of 4 genera in the sigmoid colon and 7 genera in the terminal ileum was significantly different among the 3 groups. Linear discriminant analysis effect size (LEfSe) showed that the genera of Ruminococcus, Akkermansia, Butyrivibrio, Methylobacterium, and Microbacterium and the family Erysipelotrichaceae were significantly higher in the IBS-C group, and the abundance of the genera Streptococcus, Acidaminococcus, Butyricicoccus, and Parvimonas was significantly higher in the IBS-D group. In addition, the proportion of genes responsible for the secretion system and LPS biosynthesis was significantly higher and that for methane metabolism, lysine biosynthesis, and enzyme families was significantly lower in the IBS-D group than in the IBS-C group.

CONCLUSION

Dysbiosis pattern and the function of the microbiome seem to be different among subtypes of IBS, and MAM may play a crucial role in IBS symptom generation.

Gut microbiota alteration and modulation in psychiatric disorders: Current evidence on fecal microbiota transplantation

The micro-organisms residing within the gastrointestinal tract, namely gut microbiota, form a dynamic population proper of each individual, mostly composed by bacteria which co-evolved symbiotically with human species. The advances of culture-independent techniques allowed the understanding of the multiple functions of the gut microbiota in human physiology and disease, the latter often recognising a predisposing condition in an imbalanced intestinal microbial ecosystem (dysbiosis). A complex mutual interconnection between the central nervous system (CNS), the intestine and the gut microbiota, known as "microbiota-gut-brain axis", has been hypothesized to play a pivotal role in maintaining central and peripheral functions, as well as mental health. Thus, dysbiosis with specific microbiota imbalances seems to be strongly associated with the onset psychiatric disorders by altering neurodevelopment, enhancing neurodegeneration, affecting behaviour and mood. Fecal microbiota transplantation (FMT) consists of transferring the fecal matter from a donor into the gastrointestinal tract of a recipient, and it is used to quickly modulate the gut microbiota. This review focuses on the uses of FMT in psychiatric disorders. FMT has been used to induce dysbiosis and to study the disease development, or to heal dysbiosis-related mental disorders. Overall, FMT of impaired microbiota resulted effective in enhancing psychiatric-like disturbances (mainly depression and anxiety) in recipient animals, plausibly by impairing immune system, inflammatory and metabolic pathways, neurochemical processes and neuro-transmission. On the other side, preclinical and clinical data suggest that reversing or mitigating dysbiosis seems a promising strategy to restore behavioural impairments or to obtain psychiatric symptom relief. However, current evidence is limited by the lack of procedural standardization, the paucity of human studies in the vastity of psychiatric conditions and the need of a microbiota-targeted donor-recipient matching.

Recipient factors in faecal microbiota transplantation: one stool does not fit all

Faecal microbiota transplantation (FMT) is a promising therapy for chronic diseases associated with gut microbiota alterations. FMT cures 90% of recurrent Clostridioides difficile infections. However, in complex diseases, such as inflammatory bowel disease, irritable bowel syndrome and metabolic syndrome, its efficacy remains variable. It is accepted that donor selection and sample administration are key determinants of FMT success, yet little is known about the recipient factors that affect it. In this Perspective, we discuss the effects of recipient parameters, such as genetics, immunity, microbiota and lifestyle, on donor microbiota engraftment and clinical efficacy. Emerging evidence supports the possibility that controlling inflammation in the recipient intestine might facilitate engraftment by reducing host immune system pressure on the newly transferred microbiota. Deciphering FMT engraftment rules and developing novel therapeutic strategies are priorities to alleviate the burden of chronic diseases associated with an altered gut microbiota such as inflammatory bowel disease.

Consideration of Gut Microbiome in Murine Models of Diseases

The gut microbiome (GM), a complex community of bacteria, viruses, protozoa, and fungi located in the gut of humans and animals, plays significant roles in host health and disease. Animal models are widely used to investigate human diseases in biomedical research and the GM within animal models can change due to the impact of many factors, such as the vendor, husbandry, and environment. Notably, variations in GM can contribute to differences in disease model phenotypes, which can result in poor reproducibility in biomedical research. Variation in the gut microbiome can also impact the translatability of animal models. For example, standard lab mice have different pathogen exposure experiences when compared to wild or pet store mice. As humans have antigen experiences that are more similar to the latter, the use of lab mice with more simplified microbiomes may not yield optimally translatable data. Additionally, the literature describes many methods to manipulate the GM and differences between these methods can also result in differing interpretations of outcomes measures. In this review, we focus on the GM as a potential contributor to the poor reproducibility and translatability of mouse models of disease. First, we summarize the important role of GM in host disease and health through different gut–organ axes and the close association between GM and disease susceptibility through colonization resistance, immune response, and metabolic pathways. Then, we focus on the variation in the microbiome in mouse models of disease and address how this variation can potentially impact disease phenotypes and subsequently influence research reproducibility and translatability. We also discuss the variations between genetic substrains as potential factors that cause poor reproducibility via their effects on the microbiome. In addition, we discuss the utility of complex microbiomes in prospective studies and how manipulation of the GM through differing transfer methods can impact model phenotypes. Lastly, we emphasize the need to explore appropriate methods of GM characterization and manipulation.

Biodiversity of Gut Microbiota: Impact of Various Host and Environmental Factors

Human bodies encompass very important symbiotic and mutualistic relationships with tiny creatures known as microbiota. Trillions of these tiny creatures including protozoa, viruses, bacteria, and fungi are present in and on our bodies. They play important roles in various physiological mechanisms of our bodies. In return, our bodies provide them with the habitat and food necessary for their survival. In this review, we comprehend the gut microbial species present in various regions of the gut. We can get benefits from microbiota only if they are present in appropriate concentrations, as if their concentration is altered, it will lead to dysbiosis of microbiota which further contributes to various health ailments. The composition, diversity, and functionality of gut microbiota do not remain static throughout life as they keep on changing over time. In this review, we also reviewed the various biotic and abiotic factors influencing the quantity and quality of these microbiota. These factors serve a significant role in shaping the gut microbiota population.

What Makes a Successful Donor? Fecal Transplant from Anxious-Like Rats Does Not Prevent Spinal Cord Injury-Induced Dysbiosis

Spinal cord injury (SCI) causes gut dysbiosis and an increased prevalence of depression and anxiety. Previous research showed a link between these two consequences of SCI by using a fecal transplant from healthy rats which prevented both SCI-induced microbiota changes and the subsequent development of anxiety-like behaviour. However, whether the physical and mental state of the donor are important factors in the efficacy of FMT therapy after SCI remains unknown. In the present study, rats received a fecal transplant following SCI from uninjured donors with increased baseline levels of anxiety-like behaviour and reduced proportion of Lactobacillus in their stool. This fecal transplant increased intestinal permeability, induced anxiety-like behaviour, and resulted in minor but long-term alterations in the inflammatory state of the recipients compared to vehicle controls. There was no significant effect of the fecal transplant on motor recovery in rehabilitative training, suggesting that anxiety-like behaviour did not affect the motivation to participate in rehabilitative therapy. The results of this study emphasize the importance of considering both the microbiota composition and the mental state of the donor for fecal transplants following spinal cord injury.

Mining microbes for mental health: Determining the role of microbial metabolic pathways in human brain health and disease

There is increasing knowledge regarding the role of the microbiome in modulating the brain and behaviour. Indeed, the actions of microbial metabolites are key for appropriate gut-brain communication in humans. Among these metabolites, short-chain fatty acids, tryptophan, and bile acid metabolites/pathways show strong preclinical evidence for involvement in various aspects of brain function and behaviour. With the identification of neuroactive gut-brain modules, new predictive tools can be applied to existing datasets. We identified 278 studies relating to the human microbiota-gut-brain axis which included sequencing data. This spanned across psychiatric and neurological disorders with a small number also focused on normal behavioural development. With a consistent bioinformatics pipeline, thirty-five of these datasets were reanalysed from publicly available raw sequencing files and the remainder summarised and collated. Among the reanalysed studies, we uncovered evidence of disease-related alterations in microbial metabolic pathways in Alzheimer's Disease, schizophrenia, anxiety and depression. Amongst studies that could not be reanalysed, many sequencing and technical limitations hindered the discovery of specific biomarkers of microbes or metabolites conserved across studies. Future studies are warranted to confirm our findings. We also propose guidelines for future human microbiome analysis to increase reproducibility and consistency within the field.

Of bowels, brain and behavior: A role for the gut microbiota in psychiatric comorbidities in irritable bowel syndrome

BACKGROUND

The gastrointestinal microbiota has emerged as a key regulator of gut-brain axis signalling with important implications for neurogastroenterology. There is continuous bidirectional communication between the gut and the brain facilitated by neuronal, endocrine, metabolic, and immune pathways. The microbiota influences these signalling pathways via several mechanisms. Studies have shown compositional and functional alterations in the gut microbiota in stress-related psychiatric disorders. Gut microbiota reconfigurations are also a feature of irritable bowel syndrome (IBS), a gut-brain axis disorder sharing high levels of psychiatric comorbidity including both anxiety and depression. It remains unclear how the gut microbiota alterations in IBS align with both core symptoms and these psychiatric comorbidities.

METHODS

In this review, we highlight common and disparate features of these microbial signatures as well as the associated gut-brain axis signalling pathways. Studies suggest that patients with either IBS, depression or anxiety, alone or comorbid, present with alterations in gut microbiota composition and harbor immune, endocrine, and serotonergic system alterations relevant to the common pathophysiology of these comorbid conditions.

KEY RESULTS

Research has illustrated the utility of fecal microbiota transplantation in animal models, expanding the evidence base for a potential causal role of disorder-specific gut microbiota compositions in symptom set expression. Moreover, an exciting study by Constante and colleagues in this issue highlights the possibility of counteracting this microbiota-associated aberrant behavioral phenotype with a probiotic yeast, Saccharomyces boulardii CNCM I-745.

CONCLUSIONS AND INFERENCES

Such data highlights the potential for therapeutic targeting of the gut microbiota as a valuable strategy for the management of comorbid psychiatric symptoms in IBS.

Evidence-based clinical practice guidelines for irritable bowel syndrome 2020

Managing irritable bowel syndrome (IBS) has attracted international attention because single-agent therapy rarely relieves bothersome symptoms for all patients. The Japanese Society of Gastroenterology (JSGE) published the first edition of evidence-based clinical practice guidelines for IBS in 2015. Much more evidence has accumulated since then, and new pharmacological agents and non-pharmacological methods have been developed. Here, we report the second edition of the JSGE-IBS guidelines comprising 41 questions including 12 background questions on epidemiology, pathophysiology, and diagnostic criteria, 26 clinical questions on diagnosis and treatment, and 3 questions on future research. For each question, statements with or without recommendations and/or evidence level are given and updated diagnostic and therapeutic algorithms are provided based on new evidence. Algorithms for diagnosis are requisite for patients with chronic abdominal pain or associated symptoms and/or abnormal bowel movement. Colonoscopy is indicated for patients with one or more alarm symptoms/signs, risk factors, and/or abnormal routine examination results. The diagnosis is based on the Rome IV criteria. Step 1 therapy consists of diet therapy, behavioral modification, and gut-targeted pharmacotherapy for 4 weeks. For non-responders, management proceeds to step 2 therapy, which includes a combination of different mechanistic gut-targeted agents and/or psychopharmacological agents and basic psychotherapy for 4 weeks. Step 3 therapy is for non-responders to step 2 and comprises a combination of gut-targeted pharmacotherapy, psychopharmacological treatments, and/or specific psychotherapy. These updated JSGE-IBS guidelines present best practice strategies for IBS patients in Japan and we believe these core strategies can be useful for IBS diagnosis and treatment globally.