Specific members of the predominant gut microbiota predict pouchitis following colectomy and IPAA in UC

Toxigenic Clostridium perfringens Isolated from At-Risk Paediatric Inflammatory Bowel Disease Patients

BACKGROUND AND AIMS

This study aimed to identify microbial drivers of inflammatory bowel disease [IBD], by investigating mucosal-associated bacteria and their detrimental products in IBD patients.

METHODS

We directly cultured bacterial communities from mucosal biopsies from paediatric gastrointestinal patients and examined for pathogenicity-associated traits. Upon identifying Clostridium perfringens as toxigenic bacteria present in mucosal biopsies, we isolated strains and further characterized toxicity and prevalence.

RESULTS

Mucosal biopsy microbial composition differed from corresponding stool samples. C. perfringens was present in eight of nine patients' mucosal biopsies, correlating with haemolytic activity, but was not present in all corresponding stool samples. Large IBD datasets showed higher C. perfringens prevalence in stool samples of IBD adults [18.7-27.1%] versus healthy controls [5.1%]. In vitro, C. perfringens supernatants were toxic to cell types beneath the intestinal epithelial barrier, including endothelial cells, neuroblasts, and neutrophils, while the impact on epithelial cells was less pronounced, suggesting C. perfringens may be particularly damaging when barrier integrity is compromised. Further characterization using purified toxins and genetic insertion mutants confirmed perfringolysin O [PFO] toxin was sufficient for toxicity. Toxin RNA signatures were found in the original patient biopsies by PCR, suggesting intestinal production. C. perfringens supernatants also induced activation of neuroblast and dorsal root ganglion neurons in vitro, suggesting C. perfringens in inflamed mucosal tissue may directly contribute to abdominal pain, a frequent IBD symptom.

CONCLUSIONS

Gastrointestinal carriage of certain toxigenic C. perfringens may have an important pathogenic impact on IBD patients. These findings support routine monitoring of C. perfringens and PFO toxins and potential treatment in patients.

Antibiotic Use in the 12 Months Prior to Ileal Pouch-Anal Anastomosis Increases the Risk for Pouchitis

BACKGROUND & AIMS

Pouchitis is the most common complication after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC); however, clinical and environmental risk factors for pouchitis remain poorly understood. We explored the relationship between specific clinical factors and the incidence of pouchitis.

METHODS

We established a population-based cohort of all adult persons in Denmark undergoing proctocolectomy with IPAA for UC from 1996-2020. We used Cox proportional hazard modeling to assess the impact of antibiotic, nonsteroidal anti-inflammatory drug (NSAID) exposure, and appendectomy on diagnosis of acute pouchitis in the first 2 years after IPAA surgery.

RESULTS

Among 1616 eligible patients, 46% developed pouchitis in the first 2 years after IPAA. Antibiotic exposure in the 12 months before IPAA was associated with an increased risk of pouchitis (adjusted hazard ratio [aHR], 1.41; 95% confidence interval [CI], 1.22-1.64) after adjusting for anti-tumor necrosis factor alpha use and sex. Compared with persons without any antibiotic prescriptions in the 12 months before IPAA, the risk of pouchitis was increased in those with 1 or 2 courses of antibiotics in that period (aHR, 1.30; 95% CI, 1.11-1.52) and 3 or more courses (aHR, 1.77; 95% CI, 1.41-2.21). NSAID exposure in the 12 months before IPAA and appendectomy were not associated with risk of acute pouchitis (P = .201 and P = .865, respectively).

CONCLUSIONS

In this population-based cohort study, we demonstrated that antibiotic exposure in the 12 months before IPAA is associated with an increased risk of acute pouchitis. Future prospective studies may isolate specific microbial changes in at-risk patients to drive earlier interventions.

Acupuncture influences multiple diseases by regulating gut microbiota

Acupuncture, an important green and side effect-free therapy in traditional Chinese medicine, is widely use both domestically and internationally. Acupuncture can interact with the gut microbiota and influence various diseases, including metabolic diseases, gastrointestinal diseases, mental disorders, nervous system diseases, and other diseases. This review presents a thorough analysis of these interactions and their impacts and examines the alterations in the gut microbiota and the potential clinical outcomes following acupuncture intervention to establish a basis for the future utilization of acupuncture in clinical treatments.

Altered Bile Acid and Pouch Microbiota Composition in Patients With Chronic Pouchitis

BACKGROUND

Patients with ulcerative colitis and total abdominal proctocolectomy with ileal pouch-anal anastomosis have a 50% risk of pouchitis and a 5% to 10% risk of chronic pouchitis.

AIMS

The goal of the study was to compare pouch microbiota and stool bile acid composition in patients with chronic pouchitis, chronic pouchitis and primary sclerosing cholangitis, and normal pouch.

METHODS

Patients with ulcerative colitis and ileal pouch-anal anastomosis were recruited from March 20, 2014, to August 6, 2019, and categorized into normal pouch, chronic pouchitis, and chronic pouchitis/primary sclerosing cholangitis groups. Stool samples were subjected to bile acid quantification and 16S rRNA gene sequencing. Statistical comparisons of absolute bile acid abundance and pouch microbiota α-diversity, β-diversity, and taxa abundance were performed among the patient groups.

RESULTS

A total of 51 samples were analyzed. Both α-diversity (P = .01, species richness) and β-diversity (P = .001) significantly differed among groups. Lithocholic acid was significantly lower in patients with chronic pouchitis/primary sclerosing cholangitis than in those with chronic pouchitis (P = .01) or normal pouch (P = .03). Decreased α-diversity was associated with an increased primary to secondary bile acid ratio (P = .002), which was also associated with changes in β-diversity (P = .006).

CONCLUSIONS

Pouch microbiota α- and β-diversity differed among patients with normal pouch, chronic pouchitis, and chronic pouchitis/primary sclerosing cholangitis. Lithocholic acid level and primary to secondary bile acid ratio were highly associated with pouch microbiota richness, structure, and composition. These findings emphasize the associations between pouch microbiota and bile acid composition in dysbiosis and altered metabolism, suggesting that secondary bile acids are decreased in chronic pouchitis.

Pouchitis: pathophysiology and management

Pouchitis is an acute or chronic inflammatory disease of the ileal reservoir. It is common after restorative proctocolectomy with ileal pouch-anal anastomosis, and treatment of chronic antibiotic-refractory pouchitis has proven challenging. Most cases of acute pouchitis evolve into chronic pouchitis. The aetiology of acute pouchitis is likely to be partly related to the gut microbiota, whereas the pathophysiology of chronic pouchitis involves abnormal interactions between genetic disposition, faecal stasis, the gut microbiota, dysregulated host immunity, surgical techniques, ischaemia and mesentery-related factors. Pouchoscopy with biopsy is the most valuable modality for diagnosis, disease monitoring, assessment of treatment response, dysplasia surveillance and delivery of endoscopic therapy. Triggering or risk factors, such as Clostridioides difficile infection and use of non-steroidal anti-inflammatory drugs, should be modified or eradicated. In terms of treatment, acute pouchitis usually responds to oral antibiotics, whereas chronic antibiotic-refractory pouchitis often requires induction and maintenance therapy with integrin, interleukin or tumour necrosis factor inhibitors. Chronic pouchitis with ischaemic features, fistulae or abscesses can be treated with hyperbaric oxygen therapy.

The urinary and prostatic microbiome in non-neurogenic male LUTS/BPH: A systematic review

INTRODUCTION

Despite advancements in the treatment of benign prostatic hyperplasia (BPH), the mechanisms underlying BPH development and progression remain elusive and lacks a one-size-fits-all therapeutic solution. Prostatic inflammation contributes to BPH and lower urinary tract symptoms (LUTS), but the initial trigger remains unknown. Current research suggests dysbiosis of the urinary microbiome as a potential culprit. This systematic review explores the emerging field of the male urinary and prostatic microbiome and its relationship with BPH/LUTS.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A systematic search in the Pubmed and Scopus databases was performed using specific terms. Inclusion criteria considered male non-neurogenic patients with LUTS due to BPH with analyses of urinary microbiome, concerning evaluation of English-language publications with relevance.

RESULTS

Among seven articles involving 542 patients, there was an association between male LUTS/BPH and the urinary microbiome. Findings indicate a correlation between urinary microbiome dysbiosis and LUTS severity, with specific bacterial genera such as Streptococcus and Haemophilus linked to higher International Prostate Symptom Score (IPSS) scores and PSA levels. The fecal microbiome may be associated with LUTS, although contradictory findings are reported. The review also highlights methodological inconsistencies, small sample sizes, few negative controls and a lack of comprehensive clinical data as major limitations.

CONCLUSIONS

While there is an undeniable correlation between the microbiome and LUTS/BPH, future research should aim to standardize sampling techniques and expand the score to include functional microbiome characterization, potentially leading to novel, microbiome-targeted therapeutic strategies for BPH.

Gut microbiome in the Graves' disease: Comparison before and after anti-thyroid drug treatment

While several studies have proposed a connection between the gut microbiome and the pathogenesis of Graves's disease (GD), there has been a lack of reports on alteration in microbiome following using anti-thyroid drug treatment (ATD) to treat GD. Stool samples were collected from newly diagnosed GD patients provided at baseline and after 6 months of ATD treatment. The analysis focused on investigating the association between the changes in the gut microbiome and parameter including thyroid function, thyroid-related antibodies, and the symptom used to assess hyperthyroidism before and after treatment. A healthy control (HC) group consisting of data from 230 healthy subjects (110 males and 120 females) sourced from the open EMBL Nucleotide Sequence Database was included. Twenty-nine GD patients (14 males and 15 females) were enrolled. The analysis revealed a significant reduction of alpha diversity in GD patients. However, after ATD treatment, alpha diversity exhibited a significant increase, restored to levels comparable to the HC levels. Additionally, GD patients displayed lower levels of Firmicutes and higher levels of Bacteroidota. Following treatment, there was an increased in Firmicutes and a decrease in Bacteroidota, resembling levels found in the HC levels. The symptoms of hyperthyroidism were negatively associated with Firmicutes and positively associated with Bacteroidota. GD had significantly lower levels of Roseburia, Lachnospiraceaea, Sutterella, Escherichia-shigella, Parasuterella, Akkermansia, and Phascolarctobacterium compared to HC (all p < 0.05). Post-treatment, Subdoligranulum increased (p = 0.010), while Veillonella and Christensenellaceaea R-7 group decreased (p = 0.023, p = 0.029, respectively). Anaerostipes showed a significant association with both higher smoking pack years and TSHR-Ab levels, with greater abundantce observed in smokers among GD (p = 0.16). Although reduced ratio of Firmicutes/Bacteroidetes was evident in GD, this ratio recovered after treatment. This study postulates the involvement of the gut microbiome in the pathogenesis of GD, suggesting potential restoration after treatment.

The aetiology of pouchitis in patients with inflammatory bowel disease

Restorative proctocolectomy with ileal pouch-anal anastomosis is a treatment option for patients with refractory ulcerative colitis. Pouchitis is the most common complication, representing a spectrum of diseases ranging from acute antibiotic-responsive type to chronic antibiotic-refractory. Early accurate diagnosis using a combined assessment of symptoms, endoscopy and histology is important for both treatment and prognostication. Most patients respond well to antibiotic therapy; however, management of chronic antibiotic-refractory pouchitis remains a challenge, and treatment options are based on small studies. Pouchitis is thought to be driven by the interaction between genetics, the immune system and the environment but as yet a causal relationship has yet to be identified. Further longitudinal assessment of the pouch integrating new technologies may help us understand the factors driving pouchitis. This review outlines the currently understood risk factors and aetiology of pouchitis.

An Update on the Role and Potential Molecules in Relation to Ruminococcus gnavus in Inflammatory Bowel Disease, Obesity and Diabetes Mellitus

Ruminococcus gnavus (R. gnavus) is a gram-positive anaerobe commonly resides in the human gut microbiota. The advent of metagenomics has linked R. gnavus with various diseases, including inflammatory bowel disease (IBD), obesity, and diabetes mellitus (DM), which has become a growing area of investigation. The initial focus of research primarily centered on assessing the abundance of R. gnavus and its potential association with disease presentation, taking into account variations in sample size, sequencing and analysis methods. However, recent investigations have shifted towards elucidating the underlying mechanistic pathways through which R. gnavus may contribute to disease manifestation. In this comprehensive review, we aim to provide an updated synthesis of the current literature on R. gnavus in the context of IBD, obesity, and DM. We critically analyze relevant studies and summarize the potential molecular mediators implicated in the association between R. gnavus and these diseases. Across numerous studies, various molecules such as methylation-controlled J (MCJ), glucopolysaccharides, ursodeoxycholic acid (UDCA), interleukin(IL)-10, IL-17, and capric acid have been proposed as potential contributors to the link between R. gnavus and IBD. Similarly, in the realm of obesity, molecules such as hydrogen peroxide, butyrate, and UDCA have been suggested as potential mediators, while glycine ursodeoxycholic acid (GUDCA) has been implicated in the connection between R. gnavus and DM. Furthermore, it is imperative to emphasize the necessity for additional studies to evaluate the potential efficacy of targeting pathways associated with R. gnavus as a viable strategy for managing these diseases. These findings have significantly expanded our understanding of the functional role of R. gnavus in the context of IBD, obesity, and DM. This review aims to offer updated insights into the role and potential mechanisms of R. gnavus, as well as potential strategies for the treatment of these diseases.

The practice of fecal microbiota transplantation in inflammatory bowel disease

Current evidence posits a central role for gut microbiota and the metabolome in the pathogenesis and progression of inflammatory bowel disease (IBD). Fecal microbiota transplantation (FMT) has been established as a means to manipulate this microbiome safely and sustainably. Several aspects of the technical improvement including pretreatment with antibiotics, use of frozen stool samples as well as short donor-to-recipient time are proposed to improve its response rates. Its efficacy in ulcerative colitis has been proven in clinical trials while data is emerging for Crohn's disease. This review describes briefly the biology behind FMT, the available evidence for its use in IBD, and the host, recipient and procedural factors which determine the clinical outcomes.

Elucidating the role of diet in maintaining gut health to reduce the risk of obesity, cardiovascular and other age-related inflammatory diseases: recent challenges and future recommendations

A healthy balanced diet is crucial in protecting the immune system against infections and diseases. Poor diets, such as the Western diet, contribute to the development of metabolic diseases, hypertension, and obesity. Microbiota, primarily composed of different microorganisms and residing in the gastrointestinal tract (GIT), also play a significant role in maintaining gut health. Polyphenols and probiotics found in fruits, vegetables, whole grains, legumes, nuts, and seeds promote gut health and support the growth of beneficial bacteria. Different types of diets, their categories, and their impact on health are also mentioned. The relationship between diet, gut health, and the risk of developing obesity, cardiovascular diseases, and inflammatory diseases is discussed in this review article. The rationale behind the review concludes future recommendations for maintaining gut health and reducing the occurrence of obesity, cardiometabolic diseases, and other inflammatory diseases. There is also the need for standardized research methods, long-term studies, and translating scientific knowledge into practical dietary recommendations.

Tuft cells utilize taste signaling molecules to respond to the pathobiont microbe Ruminococcus gnavus in the proximal colon

Tuft cells are a type of rare epithelial cells that have been recently found to utilize taste signal transduction pathways to detect and respond to various noxious stimuli and pathogens, including allergens, bacteria, protists and parasitic helminths. It is, however, not fully understood how many different types of pathogens they can sense or what exact molecular mechanisms they employ to initiate targeted responses. In this study, we found that an anaerobic pathobiont microbe, Ruminococcus gnavus (R. gnavus), can induce tuft cell proliferation in the proximal colon whereas the microbe's lysate can stimulate these proximal colonic tuft cells to release interleukin-25 (IL-25). Nullification of the Gng13 and Trpm5 genes that encode the G protein subunit Gγ13 and transient receptor potential ion channel Trpm5, respectively, or application of the Tas2r inhibitor allyl isothiocyanate (AITC), G protein Gβγ subunit inhibitor Gallein or the phospholipase Cβ2 (PLCβ2) inhibitor U73122 reduces R. gnavus-elicited tuft cell proliferation or IL-25 release or both. Furthermore, Gng13 conditional knockout or Trpm5 knockout diminishes the expression of gasdermins C2, C3 and C4, and concomitantly increases the activated forms of caspases 3, 8 and 9 as well as the number of TUNEL-positive apoptotic cells in the proximal colon. Together, our data suggest that taste signal transduction pathways are not only involved in the detection of R. gnavus infection, but also contribute to helping maintain gasdermin expression and prevent apoptotic cell death in the proximal colon, and these findings provide another strategy to combat R. gnavus infection and sheds light on new roles of taste signaling proteins along with gasdermins in protecting the integrity of the proximal colonic epithelium.

From-Toilet-to-Freezer: A Review on Requirements for an Automatic Protocol to Collect and Store Human Fecal Samples for Research Purposes

The composition, viability and metabolic functionality of intestinal microbiota play an important role in human health and disease. Studies on intestinal microbiota are often based on fecal samples, because these can be sampled in a non-invasive way, although procedures for sampling, processing and storage vary. This review presents factors to consider when developing an automated protocol for sampling, processing and storing fecal samples: donor inclusion criteria, urine-feces separation in smart toilets, homogenization, aliquoting, usage or type of buffer to dissolve and store fecal material, temperature and time for processing and storage and quality control. The lack of standardization and low-throughput of state-of-the-art fecal collection procedures promote a more automated protocol. Based on this review, an automated protocol is proposed. Fecal samples should be collected and immediately processed under anaerobic conditions at either room temperature (RT) for a maximum of 4 h or at 4 °C for no more than 24 h. Upon homogenization, preferably in the absence of added solvent to allow addition of a buffer of choice at a later stage, aliquots obtained should be stored at either -20 °C for up to a few months or -80 °C for a longer period-up to 2 years. Protocols for quality control should characterize microbial composition and viability as well as metabolic functionality.

Ruminococcus gnavus bacteremia: Literature review and a case report associated with acute flare of ulcerative colitis in an immunocompromised patient

We present a case of bacteremia caused by Ruminococcus gnavus in an immunocompromised patient. R. gnavus is a Gram-positive strict anaerobe bacterium that forms chains. The bacteremia has been associated with an acute flare of ulcerative colitis. Anaerobic bacteremia is becoming increasingly frequent in patients with compromised gastrointestinal barrier. The role of the human microbiota and its alterations in the pathogenesis of immune-related diseases is an expanding area of interest. R. gnavus has been identified as a microorganism that may be responsible for the development of these diseases. The contribution of anaerobic bacteria to the pathogenesis of inflammatory bowel disease (IBD) is discussed, and cases reported up until 2023 were reviewed.

Potential risk of tamoxifen: gut microbiota and inflammation in mice with breast cancer

Objective

Tamoxifen is an effective anti-tumor medicine, but evidence has been provided on tamoxifen-related inflammation as well as its impact on gut microbiota. In this study, we aimed to investigate tamoxifen-induced gut microbiota and inflammation alteration.

Methods

We established a BC xenograft mouse model using the MCF-7 cell line. 16S rRNA gene sequencing was used to investigate gut microbiota. qRT-PCR, western blotting, and cytometric bead array were used to investigate inflammation-related biomarkers. Various bioinformatic approaches were used to analyze the data.

Results

Significant differences in gut microbial composition, characteristic taxa, and microbiome phenotype prediction were observed between control, model, and tamoxifen-treated mice. Furthermore, protein expression of IL-6 and TLR5 was up-regulated in tamoxifen-treated mice, while the mRNA of Tlr5 and Il-6, as well as protein expression of IL-6 and TLR5 in the model group, were down-regulated in the colon. The concentration of IFN-γ, IL-6, and IL12P70 in serum was up-regulated in tamoxifen-treated mice. Moreover, correlation-based clustering analysis demonstrated that inflammation-negatively correlated taxa, including Lachnospiraceae-UCG-006 and Anaerotruncus, were enriched in the model group, while inflammation-positively correlated taxa, including Prevotellaceae_UCG_001 and Akkermansia, were enriched in the tamoxifen-treated group. Finally, colon histologic damage was observed in tamoxifen-treated mice.

Conclusion

Tamoxifen treatment significantly altered gut microbiota and increased inflammation in the breast cancer xenograft mice model. This may be related to tamoxifen-induced intestinal epithelial barrier damage and TLR5 up-regulation.

Dietary Implications of the Bidirectional Relationship between the Gut Microflora and Inflammatory Diseases with Special Emphasis on Irritable Bowel Disease: Current and Future Perspective

The immune system is vital for safeguarding the human body against infections and inflammatory diseases. The role of diet and meal patterns in modulating immune function is complex, and highlighting this topic is crucial for identifying potential ways to improve immune health. In Europe, the Mediterranean diet and Western diet are the most common dietary patterns, and gaining an understanding of how they affect immune function is essential for public health. There are numerous inflammatory diseases that are observed in younger and older people. Some of the common diseases include polymyalgia rheumatica (PMR), spinal muscular atrophy (SMA), vasculitis, sarcopenia, cirrhosis, cancer, and fibromyalgia, but the main focus in this review article is on irritable bowel disease (IBD). In general, dietary choices can have an immense impact on the microbial flora of the gut in people with inflammatory diseases. The intake of Mediterranean-style foods promotes the growth of healthy bacteria that enhances the function of the immune system. On the other hand, it is mostly seen that the intake of Western-style foods leads to the growth of harmful gut bacteria that contributes to inflammation and disease development by weakening the immune system. Additionally, inflammation in the gut can impact brain function, leading to mood disorders, such as anxiety and depression. Rare inflammatory diseases, such as psoriasis and sarcoidosis, are of main interest in this article. All the above-mentioned common and rare inflammatory diseases have a certain relationship with the microbiota of the gut. The gut microbiome plays a significant role in IBD; fiber and prebiotic interventions may represent promising adjunct therapies for pediatric IBD by targeting the gut microbiome. By advancing a good overall arrangement of microorganisms in the stomach through dietary mediations, working on the side effects and alleviating of diseases might be conceivable. The gut microbiota can be affected differently by various dietary fatty acid types. There is also an involvement of genetics in the progression of IBD, such as transcriptional factors, and one gene of interest is the LCT gene, which encodes for lactase, an enzyme responsible for digesting lactose in the gut.

Bacillus licheniformis prevents and reduces anxiety-like and depression-like behaviours

As common mental disorders, depression and anxiety impact people all around the world. Recent studies have found that the gut microbiome plays an important role in mental health. It is becoming possible to treat mental disorders by regulating the composition of the gut microbiota. Bacillus licheniformis is a probiotic used to treat gut diseases through balancing the gut microbiome during lasting years. Considering the role of gut microbiota in the gut-brain axis, this study used chronic unpredictable mild stress (CUMS) model rats to explore whether Bacillus licheniformis can prevent and treat depression and anxiety. We found that B. licheniformis reduced the depressive-like and anxiety-like behaviours of the rats during the CUMS process. Meanwhile, B. licheniformis changed the gut microbiota composition; increased the short chain fatty acids (SCFAs) in the colon, decreased kynurenine, norepinephrine, and glutamate levels; and increased the tryptophan, dopamine, epinephrine, and γ-aminobutyric acid (GABA) in the brain. After correlation analysis, we found Parabacteroides, Anaerostipes, Ruminococcus-2, and Blautia showed significant correlation with neurotransmitters and SCFAs, indicating the gut microbiome plays an important role in B. licheniformis reducing depressive-like behaviours. Therefore, this study suggested B. licheniformis may prevent depressive-like and anxiety-like behaviours while regulating the gut microbiota composition and increasing the SCFA levels in the colon to alter the levels of the neurotransmitters in the brain. KEY POINTS: • B. licheniformis reduced depressive-like and anxiety-like behaviours induced by the chronic unpredictable mild stress. • GABA levels in the brain are assonated with B. licheniformis regulating depressive-like and anxiety-like behaviours. • Gut microbiota composition alteration followed by metabolic changes may play a role in the GABA levels increase.

Ruminococcus gnavus: friend or foe for human health

Ruminococcus gnavus was first identified in 1974 as a strict anaerobe in the gut of healthy individuals, and for several decades, its study has been limited to specific enzymes or bacteriocins. With the advent of metagenomics, R. gnavus has been associated both positively and negatively with an increasing number of intestinal and extraintestinal diseases from inflammatory bowel diseases to neurological disorders. This prompted renewed interest in understanding the adaptation mechanisms of R. gnavus to the gut, and the molecular mediators affecting its association with health and disease. From ca. 250 publications citing R. gnavus since 1990, 94% were published in the last 10 years. In this review, we describe the biological characterization of R. gnavus, its occurrence in the infant and adult gut microbiota and the factors influencing its colonization of the gastrointestinal tract; we also discuss the current state of our knowledge on its role in host health and disease. We highlight gaps in knowledge and discuss the hypothesis that differential health outcomes associated with R. gnavus in the gut are strain and niche specific.

Managing ulcerative colitis after surgery

Management of ulcerative colitis after surgery suggested by guidelines (total proctocolectomy with ileal-pouch anal anastomosis) is a big challenge for physicians because patients who believed that their disease had been cured started experiencing very uncomfortable symptoms repeatedly. A high number of patients develop episodes of pouchitis, which is a non-specific inflammation of the pouch whose etiology is unknown. Antibiotics are the elective treatment for acute pouchitis, but regarding chronic pouchitis, this condition is very complicated to treat due to the absence of well-designed specific studies for this group of patients. Antibiotics, budesonide, and biological therapies are some of the recommended drugs for these patients, but despite their use, some need a permanent ileostomy.

Relationship Between Stages of Ileal Pouch-Anal Anastomosis, Timing of Restoration of Fecal Continuity, and Pouchitis

BACKGROUND

The most common complication following ileal pouch-anal anastomosis (IPAA) in patients with ulcerative colitis (UC) is pouchitis.

AIMS

We aimed to investigate whether a shorter period between pouch creation and restoration of fecal flow through an IPAA was associated with an increased risk of development of pouchitis within the first 2 years after IPAA.

METHODS

We performed a retrospective cohort study evaluating patients undergoing colectomy with IPAA for UC between January 1, 2004 and December 31, 2016. We used Kaplan-Meier testing and Cox Proportional Hazards Modeling to evaluate the relationship between the time between restoration of fecal continuity and time to subsequent development of pouchitis, adjusting for other clinical and demographic factors.

RESULTS

We identified 624 patients who underwent proctocolectomy with IPAA for UC, of whom 246 (39%) developed pouchitis within the first 2 years after IPAA. There was no difference when comparing the median time to restoration of continuity among those patients who developed pouchitis and those who did not (49 days vs. 49 days, p = 0.85) or in multivariable analysis. Primary sclerosing cholangitis (Hazard Ratio [HR] 2.14, 95% CI 1.12-4.08), family history of inflammatory bowel disease (HR 1.49, 95% CI 1.08-2.06), and delayed pouch creation (HR 0.75, 95% CI 0.57-1.00) were significantly associated with time to development of pouchitis.

CONCLUSION

Although a staged approach to IPAA may have benefits in the surgical management of UC, the timing interval between pouch creation and restoration of continuity did not impact the subsequent development of early pouchitis in this cohort.

Biomarkers for the Evaluation of Pouch Inflammation: A Systematic Review

Background

Ileal pouch inflammation is a common problem following ileal pouch-anal anastomosis (IPAA). Despite its prevalence, diagnosis remains multimodal and requires endoscopy. The use of biomarkers in the prediction of and/or association with pouchitis has not been well characterized. We performed a systematic review to summarize the available evidence.

Method

A search of Ovid, MEDLINE, Cochrane Library, EMBASE, and Web of Science was conducted. Inclusion criteria included studies evaluating biomarkers for the evaluation and prediction of inflammation in patients with IPAA utilizing pouchoscopy as the gold standard. Exclusion criteria included studies on the role of the microbiome or genetic markers.

Results

A total of 28 studies, 5 case-control studies, and 23 observational cohort studies were identified. Fecal biomarkers were assessed in 23 studies, of which fecal calprotectin was the most commonly studied with sensitivities ranging from 57% to 92% and specificities from 19% to 92%. Six studies examined serum biomarkers. None of the serum biomarkers demonstrated a high sensitivity or specificity in association with pouch inflammation. Six studies described the longitudinal assessment of biomarkers. Of these studies, only three reported a predictive role of biomarkers in diagnosing endoscopic inflammation.

Conclusions

Biomarkers have emerged as a potential option to improve the management of pouchitis given the relative ease of sampling compared to pouchoscopy. Unfortunately, the evaluated biomarkers have not consistently demonstrated accuracy in predicting inflammation. Moreover, these biomarkers have not been reliably shown to be sensitive or specific in association with endoscopic pouch inflammation to merit their widespread use in clinical practice.

New insights into natural products that target the gut microbiota: Effects on the prevention and treatment of colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant carcinomas. CRC is characterized by asymptomatic onset, and most patients are already in the middle and advanced stages of disease when they are diagnosed. Inflammatory bowel disease (IBD) and the inflammatory-cancer transformation of advanced colorectal adenoma are the main causes of CRC. There is an urgent need for effective prevention and intervention strategies for CRC. In recent years, rapid research progress has increased our understanding of gut microbiota. Meanwhile, with the deepening of research on the pathogenesis of colorectal cancer, gut microbiota has been confirmed to play a direct role in the occurrence and treatment of colorectal cancer. Strategies to regulate the gut microbiota have potential value for application in the prevention and treatment of CRC. Regulation of gut microbiota is one of the important ways for natural products to exert pharmacological effects, especially in the treatment of metabolic diseases and tumours. This review summarizes the role of gut microbiota in colorectal tumorigenesis and the mechanism by which natural products reduce tumorigenesis and improve therapeutic response. We point out that the regulation of gut microbiota by natural products may serve as a potential means of treatment and prevention of CRC.

Role of gut microbiota in postoperative complications and prognosis of gastrointestinal surgery: A narrative review

Gastrointestinal surgery is often challenging because of unexpected postoperative complications such as pouchitis, malabsorption, anastomotic leak, diarrhea, inflammatory responses, and life-threatening infections. Moreover, the gut microbiota has been shown to be associated with the complications described above. Major intestinal reconstruction, such as Roux-en-Y gastric bypass (RYGB) and ileal pouch-anal anastomosis surgery, could result in altered gut microbiota, which might lead to some of the benefits of these procedures but could also contribute to the development of postsurgical complications. Moreover, postsurgical reestablishment of the gut microbiota population is still poorly understood. Here, we review evidence outlining the role of gut microbiota in complications of gastrointestinal surgery, especially malabsorption, anastomotic leak, pouchitis, and infections. In addition, this review will evaluate the risks and benefits of live biotherapeutics in the complications of gastrointestinal surgery.

Gut Microbiota Structure and Metabolites, Before and After Treatment in Early Rheumatoid Arthritis Patients: A Pilot Study

Rheumatoid Arthritis (RA) is a chronic systemic autoimmune disease. Modifications of gut microbiota seem to be associated with the disease, but the impact of gut microbiota on therapies’ outcome remains unclear. A role of T cells in RA pathogenesis has been addressed, particularly on the Th17/Treg cells balance. Our study aimed to evaluate in early RA (ERA) patients compared to a control group, fecal gut microbiota composition, short-chain fatty acids concentrations, and the levels of circulating Th17/Treg and their own cytokines, before and after 3 months of standard treatment (Methotrexate (MTX) plus glucocorticoids). Fecal microbiota characterization was carried out on 19 ERA patients and 20 controls matched for sex and age. Significant decreased biodiversity levels, and a partition on the base of the microbiota composition, between the ERA patients at baseline compared to controls, were observed. The co-occurrent analysis of interactions revealed a characteristic clustered structure of the microbial network in controls that is lost in ERA patients where an altered connection between microbes and clinical parameters/metabolites has been reported. Microbial markers such as Acetanaerobacterium elongatum, Cristiansella massiliensis, and Gracilibacter thermotolerans resulted significantly enriched in control group while the species Blautia gnavus emerged to be more abundant in ERA patients. Our results showed an alteration in Th17/Treg balance with higher Th17 levels and lower Treg levels in ERA group respect to control at baseline, those data improved after therapy. Treatment administration and the achievement of a low disease activity/remission appear to exert a positive pressure on the structure of intestinal microbiota with the consequent restoration of biodiversity, of the structure of microbial network, and of the abundance of taxa that became closer to those presented by the subject without the disease. We also found an association between Blautia gnavus and ERA patients characterized by a significant reduction of propionic acid level. Furthermore significant differences highlighted at baseline among controls and ERA patients are no more evident after treatment. These data corroborate the role played by gut microbiota in the disease and suggest that therapy aimed to restore gut microbiota would improve treatment outcome.

Precision medicine: how multiomics will shape the future of inflammatory bowel disease?

PURPOSE OF REVIEW

In this article, we provide an overview of studies examining multiomic profiling in various clinical scenarios in the management of inflammatory bowel diseases (IBDs).

RECENT FINDINGS

IBD arises as a result of an interplay between genetic, environmental, microbial and immunologic perturbations. The access to high throughput technology as well as the decrease in costs associated with such studies has led to a growing wealth of literature examining the utility of single or multiomic profiles in the management of IBD. Such studies have commonly examined the genome (and less frequently the epigenome), transcriptome, metabolome, proteome and the gut microbial metagenome in the context of overall IBD status or specific clinical scenarios, including the disease progression or response to treatment. The findings have provided important insight into how each of these compartments reflect underlying disease pathophysiologic processes and, in turn, can influence stratification of patients for clinical management.

SUMMARY

Multiomic profiling in IBD has the potential to advance the field of personalized precision medicine in the management of IBDs.

Composite Sophora Colon-Soluble Capsule Ameliorates DSS-Induced Ulcerative Colitis in Mice via Gut Microbiota-Derived Butyric Acid and NCR+ ILC3

OBJECTIVE

To investigate the effects of composite Sophora colon-soluble Capsule (CSCC) on gut microbiota-mediated short-chain fatty acids (SCFAs) production and downstream group 3 innate lymphoid cells (ILC3s) of dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice model.

METHODS

The main components of CSCC were analyzed by hybrid ultra-high-performance liquid chromatography ion mobility spectromety quadrupole time-of-flight mass spectrometry (UHPLC-IM-QTOF/MS). Twenty-four male BALB/c mice were randomly divided into 4 groups (n=6) by using a computer algorithm-generated random digital, including control, DSS model, mesalazine, and CSCC groups. A DSS-induced colitis mice model was established to determine the effects of CSCC by recording colonic weight, colonic length, index of colonic weight, and histological colonic score. The variations in ILC3s were assessed by immunofluorescence and flow cytometry. The results of gut microbiota and SCFAs were acquired by 16s rDNA and gas chromatography-mass spectrometry (GC-MS) analysis. The expression levels of NCR⁺ ILC3^-, CCR6⁺ Nkp46^- (Lti) ILC3^-, and ILCreg-specific markers were detected by enzyme-linked immunosorbent assay, and real-time quantitative polymerase chain reaction and Western blot, respectively.

RESULTS

The main components of CSCC were matrine, ammothamnine, Sophora flavescens neoalcohol J, and Sophora oxytol U. After 7 days of treatment, CSCC significantly alleviated colitis by promoting the reproduction of intestinal probiotics manifested as upregulation of the abundance of Bacteroidetes species and specifically the Bacteroidales_S24-7 genus (P<0.05). Among the SCFAs, the content of butyric acid increased the most after CSCC treatment. Meanwhile, compared with the model group, Lti ILC3s and its biomarkers were significantly downregulated and NCR⁺ ILC3s were significantly elevated in the CSCC group (P<0.01). Further experiments revealed that ILC3s were differentiated from Lti ILC3s to NCR⁺ ILC3s, resulting in interleukin-22 production which regulates gut epithelial barrier function.

CONCLUSION

CSCC may exert a therapeutic effect on UC by improving the gut microbiota, promoting metabolite butyric acid production, and managing the ratio between NCR⁺ ILC3s and Lti ILC3s.

Preliminary Observation of the Changes in the Intestinal Flora of Patients With Graves’ Disease Before and After Methimazole Treatment

Immune dysfunction caused by environmental factors plays an important role in the development of Graves’ disease (GD), and environmental factors are closely related to the intestinal flora. Our previous study showed significant changes in the intestinal flora in GD patients compared with healthy volunteers. This study analyzed the relationships between changes in the intestinal flora, thyroid function and relevant thyroid antibodies in GD patients before and after methimazole treatment. The subjects were divided into the UGD group (18 newly diagnosed GD patients), the TGD group (10 GD patients with normal or approximately normal thyroid function after methimazole treatment) and the NC group (11 healthy volunteers). Their fresh stool samples were sent for 16S rRNA gene amplification and Illumina platform sequencing. The correlations of the relative abundance of Bifidobacterium with the levels of TRAb, TgAb and TPOAb in the NC group and the UGD group were analyzed. A total of 1,562,445 high-quality sequences were obtained. In the UGD group, the abundances of Bifidobacterium and Collinsella were higher than that in the NC group; Bacteroides abundance in the TGD group was higher than that in the NC group, while Prevotella and Dialister abundances were lower than that in the NC group; Prevotella and Collinsella abundances in the UGD group were higher than that in the TGD group. The predominant abundance distribution of Bifidobacteriaceae in the UGD group at the family level was superior to that in the NC group. The abundance of Bifidobacterium was positively correlated with the levels of TRAb, TgAb, and TPOAb. The biological diversity of the intestinal flora was reduced in GD patients. After methimazole treatment, the composition of the intestinal flora was significantly altered. The change in Bifidobacterium abundance was positively correlated with TRAb, TgAb and TPOAb, suggesting that it might be related to the immune mechanism of GD. The results of this study may deepen our understanding of the pathogenesis of GD and provide a new idea for the treatment of GD.

Nutraceuticals in the Modulation of the Intestinal Microbiota: Current Status and Future Directions

Pharmaceutical interest in the human intestinal microbiota has increased considerably, because of the increasing number of studies linking the human intestinal microbial ecology to an increasing number of non-communicable diseases. Many efforts at modulating the gut microbiota have been made using probiotics, prebiotics and recently postbiotics. However, there are other, still little-explored opportunities from a pharmaceutical point of view, which appear promising to obtain modifications of the microbiota structure and functions. This review summarizes all in vitro, in vivo and clinical studies demonstrating the possibility to positively modulate the intestinal microbiota by using probiotics, prebiotics, postbiotics, essential oils, fungus and officinal plants. For the future, clinical studies investigating the ability to impact the intestinal microbiota especially by using fungus, officinal and aromatic plants or their extracts are required. This knowledge could lead to effective microbiome modulations that might support the pharmacological therapy of most non-communicable diseases in a near future.

Treatment of pouchitis, Crohn's disease, cuffitis, and other inflammatory disorders of the pouch: consensus guidelines from the International Ileal Pouch Consortium

Pouchitis, Crohn's disease of the pouch, cuffitis, polyps, and extraintestinal manifestations of inflammatory bowel disease are common inflammatory disorders of the ileal pouch. Acute pouchitis is treated with oral antibiotics and chronic pouchitis often requires anti-inflammatory therapy, including the use of biologics. Aetiological factors for secondary pouchitis should be evaluated and managed accordingly. Crohn's disease of the pouch is usually treated with biologics and its stricturing and fistulising complications can be treated with endoscopy or surgery. The underlying cause of cuffitis determines treatment strategies. Endoscopic polypectomy is recommended for large, symptomatic inflammatory polyps and polyps in the cuff. The management principles of extraintestinal manifestations of inflammatory bowel disease in patients with pouches are similar to those in patients without pouches.

Compositional and functional alterations of gut microbiota in patients with stroke

BACKGROUND AND AIMS

There is accumulating evidence that gut microbiota plays a key role in cardiovascular diseases. Gut bacteria can transform dietary choline, l-carnitine, and trimethylamine N-oxide (TMAO) into trimethylamine, which can be oxidized into TMAO again in the liver. However, the alterations of the gut microbiota in large artery atherosclerotic (LAA) stroke and cardioembolic (CE) stroke have been less studied.

METHODS AND RESULTS

We performed a case-control study in patients with LAA and CE types of strokes. We profiled the gut microbiome using Illumina sequencing of the 16S ribosomal RNA gene (V4-V5 regions), and TMAO was determined via liquid chromatography-tandem mass spectrometry. Our results showed that the TMAO levels in the plasma of patients with LAA and CE strokes were significantly higher than those in controls (LAA stroke, 2931 ± 456.4 ng/mL; CE stroke, 4220 ± 577.6 ng/mL; healthy control, 1663 ± 117.8 ng/mL; adjusted p < 0.05). The TMAO level in the plasma of patients with LAA stroke was positively correlated with the carotid plaque area (rho = 0.333, 95% CI = 0.08-0.55, p = 0.0093). Notably, the composition and the function of gut microbiota in the LAA stroke group were significantly different from those in the control group (FDR-adjusted p-value < 0.05). There was no significant association between gut microbiota and CE stroke in our study.

CONCLUSION

This study provides evidence for significant compositional and functional alterations of the gut microbiome in patients with LAA stroke. Gut microbiota might serve as a potential biomarker for patients with LAA stroke.

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

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

Microbiome Analysis of Mucosal Ileoanal Pouch in Ulcerative Colitis Patients Revealed Impairment of the Pouches Immunometabolites

The pathogenesis of ulcerative colitis (UC) is unknown, although genetic loci and altered gut microbiota have been implicated. Up to a third of patients with moderate to severe UC require proctocolectomy with ileal pouch ano-anastomosis (IPAA). We aimed to explore the mucosal microbiota of UC patients who underwent IPAA.

METHODS

For microbiome analysis, mucosal specimens were collected from 34 IPAA individuals. Endoscopic and histological examinations of IPAA were normal in 21 cases, while pouchitis was in 13 patients. 19 specimens from the healthy control (10 from colonic and 9 from ileum) were also analyzed. Data were analyzed using an ensemble of software packages: QIIME2, coda-lasso, clr-lasso, PICRUSt2, and ALDEx2.

RESULTS

IPAA specimens had significantly lower bacterial diversity as compared to normal. The microbial composition of the normal pouch was also decreased also when compared to pouchitis. Faecalibacterium prausnitzii, Gemmiger formicilis, Blautia obeum, Ruminococcus torques, Dorea formicigenerans, and an unknown species from Roseburia were the most uncommon in pouch/pouchitis, while an unknown species from Enterobacteriaceae was over-represented. Propionibacterium acnes and Enterobacteriaceae were the species most abundant in the pouchitis and in the normal pouch, respectively. Predicted metabolic pathways among the IPAA bacterial communities revealed an important role of immunometabolites such as SCFA, butyrate, and amino acids.

CONCLUSIONS

Our findings showed specific bacterial signature hallmarks of dysbiosis and could represent bacterial biomarkers in IPAA patients useful to develop novel treatments in the future by modulating the gut microbiota through the administration of probiotic immunometabolites-producing bacterial strains and the addition of specific prebiotics and the faecal microbiota transplantation.

Computational Learning of microRNA-Based Prediction of Pouchitis Outcome After Restorative Proctocolectomy in Patients With Ulcerative Colitis

BACKGROUND

Ileal pouch-anal anastomosis (IPAA) is the standard of care after total proctocolectomy for ulcerative colitis (UC). However, inflammation often develops in the pouch, leading to acute or recurrent/chronic pouchitis (R/CP). MicroRNAs (miRNA) are used as accurate diagnostic and predictive biomarkers in many human diseases, including inflammatory bowel diseases. Therefore, we aimed to identify an miRNA-based biomarker to predict the occurrence of R/CP in patients with UC after colectomy and IPAA.

METHODS

We conducted a retrospective study in 3 tertiary centers in France. We included patients with UC who had undergone IPAA with or without subsequent R/CP. Paraffin-embedded biopsies collected from the terminal ileum during the proctocolectomy procedure were used for microarray analysis of miRNA expression profiles. Deep neural network-based classifiers were used to identify biomarkers predicting R/CP using miRNA expression and relevant biological and clinical factors in a discovery cohort of 29 patients. The classification algorithm was tested in an independent validation cohort of 28 patients.

RESULTS

A combination of 11 miRNA expression profiles and 3 biological/clinical factors predicted the outcome of R/CP with 88% accuracy (area under the curve = 0.94) in the discovery cohort. The performance of the classification algorithm was confirmed in the validation cohort with 88% accuracy (area under the curve = 0.90). Apoptosis, cytoskeletal regulation by Rho GTPase, and fibroblast growth factor signaling were the most dysregulated targets of the 11 selected miRNAs.

CONCLUSIONS

We developed and validated a computational miRNA-based algorithm for accurately predicting R/CP in patients with UC after IPAA.

Preoperative Endoscopic Activity Predicts the Occurrence of Pouchitis After Ileal Pouch-Anal Anastomosis in Ulcerative Colitis: A Multicenter Retrospective Study in China

Background: Pouchitis is the most common long-term complication after ileal pouch–anal anastomosis (IPAA) in patients with ulcerative colitis (UC). Ulcerative colitis endoscopic index of severity (UCEIS) and Mayo endoscopic score (MES) are widely used indices to evaluate endoscopic activity. This study aimed to clarify the predictive value of preoperative endoscopic activity on the occurrence of pouchitis after IPAA.

Methods: Data of patients with UC who underwent IPAA from January 2008 to January 2020 were collected retrospectively. UCEIS and MES were based on the preoperative colonoscopy findings of two independent endoscopists.

Results: A total of 102 patients with a median follow-up of 5 (interquartile range, 2–9) years were included in the study. Among them, 21.6% developed pouchitis. Compared with MES, UCEIS had a stronger correlation with pouchitis disease activity index. UCEIS ≥ 7 had the most significant receiver-operating characteristic (ROC) curve area of 0.747 with a sensitivity of 68.2% and specificity of 81.2% in predicting pouchitis, which outperformed MES of 3 with an ROC area of 0.679 with a sensitivity of 54.5% and specificity of 81.2%. Furthermore, we found that UCEIS ≥ 7 was an independent risk factor for post-IPAA pouchitis [odds ratio (OR), 8.860; 95% CI, 1.969–39.865, p < 0.001] with a higher risk than MES of 3 (OR, 5.200; 95% CI, 1.895–14.273; p = 0.001).

Conclusion: Ulcerative colitis endoscopic index of severity performed better in predicting pouchitis after IPAA than MES. Earlier and more frequent postoperative colonoscopic surveillance should be considered in patients with preoperative UCEIS ≥ 7 to detect the occurrence of pouchitis earlier.

Appendiceal inflammation in colectomy is independently correlated with early pouchitis following ileal pouch anal anastomosis in ulcerative colitis and indeterminate colitis

BACKGROUND

Appendiceal inflammation in colectomy is one of the histologic predictors of pouchitis in ulcerative colitis (UC) following ileal pouch anal anastomosis (IPAA). Fecal calprotectin level has been shown to increase 2 months prior to the onset of pouchitis. We evaluated whether inflammation and calprotectin expression in appendiceal specimens correlate with early-onset pouchitis in UC and indeterminate colitis (IC).

MATERIALS AND METHODS

IPAA (2000-2018) cases with appendix blocks available in colectomy specimens were identified (n = 93, 90 UC, 3 IC). Histologic features thought to predict pouchitis were evaluated. The degree of appendiceal inflammation was scored. Calprotectin immunostain was performed on the appendix blocks and the extent of mucosal staining was quantified. Electronic medical records were reviewed for demographics, smoking history, clinical pouchitis, time of onset of pouchitis, and clinical and endoscopic components of the Pouchitis Disease Activity Index (PDAI) score. Follow-up pouch biopsies were reviewed and scored to generate histologic PDAI score, when available.

RESULTS

Among the patients with clinical pouchitis (n = 73), moderate to severe appendiceal inflammation independently correlated with earlier pouchitis compared to no/mild inflammation (median time to pouchitis 12.0 vs. 23.8, log rank p = 0.016). Calprotectin staining correlated with inflammatory scores of the appendix (Spearman's rho, r = 0.630, p < 0.001) but not with early pouchitis (p > 0.05).

CONCLUSIONS

The presence of moderate to severe appendiceal inflammation at the time of colectomy was associated with a shorter time to pouchitis following IPAA. Calprotectin immunostain may be used to demonstrate the presence of inflammation in the appendix but its role in predicting early pouchitis remains limited.

Colectomy risk score predicts pouchitis in patients with ulcerative colitis

Risk stratification is required to improve the management of pouchitis with ulcerative colitis (UC) patients who undergo ileal pouch-anal anastomosis (IPAA). Recently, the colectomy risk score (CRS) has been used to assess UC severity and predict the need for surgery. We explored whether the CRS predicted pouchitis in patients with UC who underwent IPAA. This retrospective study included 168 UC patients who underwent IPAA. Pouchitis was diagnosed according to the pouchitis disease activity index. The primary endpoint was the cumulative incidence of pouchitis. The risk factors for pouchitis using preoperatively obtained data, including the CRS, were investigated. Based on their CRS, patients were assigned to low- (scores 0-3), intermediate- (scores 4-6), and high-risk (scores 7-9) groups. The incidence of pouchitis was estimated using the Kaplan-Meier curve. CRS validity was assessed using the Cox proportional hazards model. During the median 7.2 (interquartile range [IQR] 2.8-11.1) years' follow-up, 37 (28.5%) patients were diagnosed with pouchitis. Patients with pouchitis had significantly higher CRS than patients without pouchitis (median 7.0; IQR, 4.0-7.0 vs median 5.0; IQR, 3.0-7.0). The cumulative incidences of pouchitis in the low-, intermediate-, and high-risk groups were 10.3%, 18.3%, and 36.1% at 5 years, respectively. Thus, the incidence trended to increase significantly as CRS increased. Multivariate analysis revealed high-risk CRS status was an independent predictor of pouchitis (hazard ratio: 18.03; 95% confidence interval 1.55-210.05). CRS is useful in risk stratification for the development of subsequent pouchitis in patients with UC undergoing IPAA.

Dysbiosis of gut microbiota in inflammatory bowel disease: Current therapies and potential for microbiota-modulating therapeutic approaches

There is a growing body of evidence reinforcing the unique connections between the host microbiome, health, and diseases. Due to the extreme importance of the symbiotic relationship between the intestinal microbiome and the host, it is not surprising that any alteration in the gut microbiota would result in various diseases, including inflammatory bowel disease (IBD), Crohn's disease, (CD) and ulcerative colitis (UC). IBD is a chronic, relapsing-remitting condition that is associated with significant morbidity, mortality, compromised quality of life, and costly medical care. Dysbiosis is believed to exacerbate the progression of IBD. One of the currently used treatments for IBD are anti-tumor necrosis factor (TNF) drugs, representing a biologic therapy that is reported to have an impact on the gut microbiota composition. The efficacy of anti-TNF agents is hindered by the possibility of non-response, which occurs in 10-20% of treated patients, and secondary loss of response, which occurs in up to 30% of treated patients. This underscores the need for novel therapies and studies that evaluate the role of the gut microbiota in these conditions. The success of any therapeutic strategy for IBD depends on our understanding of the interactions that occur between the gut microbiota and the host. In this review, the health and disease IBD-associated microbiota patterns will be discussed, in addition to the effect of currently used therapies for IBD on the gut microbiota composition, as well as new therapeutic approaches that can be used to overcome the current treatment constraints.

The Microbiome as a Therapy in Pouchitis and Ulcerative Colitis

The gut microbiome has been implicated in a range of diseases and there is a rapidly growing understanding of this ecosystem's importance in inflammatory bowel disease. We are yet to identify a single microbe that causes either ulcerative colitis (UC) or pouchitis, however, reduced microbiome diversity is increasingly recognised in active UC. Manipulating the gut microbiome through dietary interventions, prebiotic and probiotic compounds and faecal microbiota transplantation may expand the therapeutic landscape in UC. Specific diets, such as the Mediterranean diet or diet rich in omega-3 fatty acids, may reduce intestinal inflammation or potentially reduce the risk of incident UC. This review summarises our knowledge of gut microbiome therapies in UC and pouchitis.

Putative Pathobionts in HLA-B27-Associated Spondyloarthropathy

Spondyloarthritis (SpA) is a group of immune mediated inflammatory diseases with a strong association to the major histocompatibility (MHC) class I molecule, HLA-B27. Although the association between HLA-B27 and AS has been known for almost 50 years, the mechanisms underlying disease pathogenesis are elusive. Over the years, three hypotheses have been proposed to explain HLA-B27 and disease association: 1) HLA B27 presents arthritogenic peptides and thus creates a pathological immune response; 2) HLA-B27 misfolding causes endoplasmic reticulum (ER) stress which activates the unfolded protein response (UPR); 3) HLA-B27 dimerizes on the cell surface and acts as a target for natural killer (NK) cells. None of these hypotheses explains SpA pathogenesis completely. Evidence supports the hypothesis that HLA-B27-related diseases have a microbial pathogenesis. In animal models of various SpAs, a germ-free environment abrogates disease development and colonizing these animals with gut commensal microbes can restore disease manifestations. The depth of microbial influence on SpA development has been realized due to our ability to characterize microbial communities in the gut using next-generation sequencing approaches. In this review, we will discuss various putative pathobionts in the pathogenesis of HLA-B27-associated diseases. We pursue whether a single pathobiont or a disruption of microbial community and function is associated with HLA-B27-related diseases. Furthermore, rather than a specific pathobiont, metabolic functions of various disease-associated microbes might be key. While the use of germ-free models of SpA have facilitated understanding the role of microbes in disease development, future studies with animal models that mimic diverse microbial communities instead of mono-colonization are indispensable. We discuss the causal mechanisms underlying disease pathogenesis including the role of these pathobionts on mucin degradation, mucosal adherence, and gut epithelial barrier disruption and inflammation. Finally, we review the various uses of microbes as therapeutic modalities including pre/probiotics, diet, microbial metabolites and fecal microbiota transplant. Unravelling these complex host-microbe interactions will lead to the development of new targets/therapies for alleviation of SpA and other HLA-B27 associated diseases.

An altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of postoperative ileus

BACKGROUND

The aim of this study is to investigate the altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of the postoperative ileus (POI).

METHODS

A laparotomy with cecal manipulation was performed to induce POI in guinea pigs. Fecal pellets were collected before the operation (the baseline) and 1, 3, and 5 days after the operation. The extracted fecal DNA was amplified and sequenced using the Illumina MiSeq sequencing system. The same POI procedures were performed after oral pretreatment of the probiotics for 7 days before operation. The effect of the probiotics on the selected taxa and fecal acetate were evaluated, as were the butyrate levels. The colonic transit was assessed by measurement of the fecal pellet output.

KEY RESULTS

The communities of the baseline and POI groups indicated significantly distinct composition. The genera Bifidobacterium and Lactobacillus were more abundant in the baseline group compared with the POI groups, and Bacteroides and Blautia were more abundant in the POI groups. Decreased abundances of the species Bifidobacterium bifidum and Bifidobacterium longum after the POI procedure were significantly increased in the probiotics group. The decreased fecal butyrate level after the POI procedure was significantly increased, and colonic transit was significantly improved in the probiotics group.

CONCLUSIONS AND INFERENCES

POI induces gut bacterial dysbiosis. Moreover, pretreatment of probiotics before operation restores the beneficial bacterial species, butyrate production, and bowel movement. The modulation of gut microbiota may help the treatment and prevention of POI.

FAM3D is essential for colon homeostasis and host defense against inflammation associated carcinogenesis

The physiological homeostasis of gut mucosal barrier is maintained by both genetic and environmental factors and its impairment leads to pathogenesis such as inflammatory bowel disease. A cytokine like molecule, FAM3D (mouse Fam3D), is highly expressed in mouse gastrointestinal tract. Here, we demonstrate that deficiency in Fam3D is associated with impaired integrity of colonic mucosa, increased epithelial hyper-proliferation, reduced anti-microbial peptide production and increased sensitivity to chemically induced colitis associated with high incidence of cancer. Pretreatment of Fam3D^−/− mice with antibiotics significantly reduces the severity of chemically induced colitis and wild type (WT) mice co-housed with Fam3D^−/− mice phenocopy Fam3D-deficiency showing increased sensitivity to colitis and skewed composition of fecal microbiota. An initial equilibrium of microbiota in cohoused WT and Fam3D^−/− mice is followed by an increasing divergence of the bacterial composition after separation. These results demonstrate the essential role of Fam3D in colon homeostasis, protection against inflammation associated cancer and normal microbiota composition.

The cytokine like protein FAM3D (Fam3D in mice) is highly expressed in the digestive tract with unknown role in colon pathophysiology. Here, by using gene deficient mice, the authors show that Fam3D is critically involved in colon homeostasis, host defense against colitis-associated carcinogenesis, and the balance of microbiota.

Functional Anatomical Changes in Ulcerative Colitis Patients Determine Their Gut Microbiota Composition and Consequently the Possible Treatment Outcome

Gut microbial composition alters in some special situations, such as in ulcerative colits (UC) after total proctocolectomy and ileal pouch-anal anastomosis (IPAA) surgery. The aim of our study was to determine the composition of the intestinal microbiome in UC patients after IPAA surgery, compared with UC patients, familial adenomatous polyposis (FAP) patients after IPAA surgery and healthy controls. Clinical data of patients, blood and faecal samples were collected. Faecal microbiota structure was determined by sequencing the V4 hypervariable region of the 16S rRNA gene. Overall, 56 patients were enrolled. Compared to the Healthy group, both the Pouch active and UC active groups had higher Enterobacteriaceae, Enterococcaceae and Pasteurellaceae abundance. The Pouch and UC groups showed distinct separation based on their alpha and beta bacterial diversities. The UC group had higher Prevotellaceae, Rikenellaceae, Ruminococcaceae abundance compared to the Pouch active group. Pouch and FAP participants showed similar bacterial community composition. There was no significant difference in the bacterial abundance between the active and inactive subgroups of the Pouch or UC groups. Gut microbiome and anatomical status together construct a functional unit that has influence on diversity, in addition to intestinal inflammation that is a part of the pathomechanism in UC.

Short- and Long-term Outcomes Following Side-to-side Strictureplasty and its Modification Over the Ileocaecal Valve for Extensive Crohn's Ileitis

BACKGROUND AND AIMS

Postoperative recurrence remains a challenging problem in patients with Crohn's disease [CD]. To avoid development of short bowel syndrome, strictureplasty techniques have therefore been proposed. We evaluated short- and long-term outcomes of atypical strictureplasties in CD patients with extensive bowel involvement.

METHODS

Side-to-side isoperistaltic strictureplasty [SSIS] was performed according to the Michelassi technique or modification of this over the ileocaecal valve [mSSIS]. Ninety-day postoperative morbidity was assessed using the comprehensive complication index [CCI]. Clinical recurrence was defined as symptomatic, endoscopically or radiologically confirmed, stricture/inflammatory lesion requiring medical treatment or surgery. Surgical recurrence was defined as the need for any surgical intervention. Endoscopic remission was defined as ≤i1, according to the modified Rutgeerts score. Deep remission was defined as the combination of endoscopic remission and absence of clinical symptoms. Perioperative factors related to clinical recurrence were evaluated.

RESULTS

A total of 52 CD patients [SSIS n = 12; mSSIS n = 40] were included. No mortality occurred. Mean CCI was 10.3 [range 0-33.7]. Median follow-up was 5.9 years [range 0.8-9.9]. Clinical recurrence [19 patients] was 29.7% and 39.6% after 3 and 5 years, respectively. Surgical recurrence [seven patients] was 2% and 14.1% after 3 and 5 years, respectively. At the end of the follow-up, 92% of patients kept the original strictureplasty and deep remission was observed in 25.7% of the mSSIS patients. None of the perioperative variables considered showed a significant association with clinical recurrence.

CONCLUSIONS

SSIS is safe, effective, and provides durable disease control in patients with extensive CD ileitis.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps

It is known and accepted that the gut microbiota composition of an organism has an impact on its health. Many studies deal with this topic, the majority discussing gastrointestinal health. Adenomatous colon polyps have a high prevalence as colon cancer precursors, but in many cases, they are hard to diagnose in their early stages. Gut microbiota composition correlated with the presence of adenomatous colon polyps may be a noninvasive and efficient tool for diagnosis with a high impact on human wellbeing and favorable health care costs. This review is meant to analyze the gut microbiota correlated with the presence of adenomatous colon polyps as the first step for early diagnosis, prophylaxis, and treatment.

Iron at the host-microbe interface

Iron is an essential micronutrient for nearly all living organisms. In addition to facilitating redox reactions, iron is bound by metalloproteins that participate in a variety of biological processes. As the bioavailability of free iron in host environments is extremely low, iron lies at the center of a battle for nutrients between microbes and their host. Mucosal surfaces such as the respiratory and gastrointestinal tracts are constantly exposed to commensal and pathogenic microorganisms. Whereas a key strategy of mammalian antimicrobial defense is to deprive microbes of iron, pathogens and some commensals have evolved effective strategies to circumvent iron limitation. Here we provide an overview of mechanisms underpinning the tug-of-war for iron between microbes and their host, with a particular focus on mucosal surfaces.

Ruminococcus gnavus bacteraemia in a patient with multiple haematological malignancies

We present a case of Ruminococcus gnavus sepsis in a woman suffering from multiple myeloma and myelodysplastic syndrome. R. gnavus, a Gram-positive coccus and a gut commensal, has been described in nine cases of infection in the literature, with most infections having occurred in patients with either gastrointestinal symptoms or prosthesis infections. In this case, R gnavus was identified by mass spectrometry, and showed susceptibility to penicillin, meropenem, tetracycline, metronidazole and clindamycin. The patient was successfully treated initially with intravenous piperacillin/tazobactam and metronidazole, and then switched to oral penicillin and metronidazole. The cause of infection is hypothesized to have been a shift in the gut microbiota towards an excess growth of R. gnavus caused by immunosuppression, and bacterial translocation across a vulnerable mucosal barrier due to prednisolone treatment and severe thrombocytopenia.

Interplay of intestinal microbiota and mucosal immunity in inflammatory bowel disease: a relationship of frenemies

Inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn's disease, are chronic inflammatory disorders of the gastrointestinal tract. With in-depth studies on the mechanisms of the initiation and development of IBD, increasing lines of evidence have focused on the intestinal microbiota in the pathogenesis of IBD. The imbalance between the host and intestinal microbiota induces dysregulated immune response in intestinal mucosa and plays a pivotal role in the initiation of disease and ongoing bowel destruction. This review focuses on recent advances in intestinal microbiota regulation of mucosal immune response as well as novel approaches based on intestinal microbiota alterations in the diagnosis and evaluation of therapeutic response in IBD.

The role of fecal calprotectin in the diagnosis of acute pouchitis following IPAA for ulcerative colitis: a systematic clinical review

PURPOSE

Total proctocolectomy (TPC) with ileal pouch anal anastomosis (IPAA) is commonly performed for patients with refractory ulcerative colitis (UC). Pouchitis occurs in 20-50% of these patients. Fecal calprotectin is a biomarker that correlates well with the pouchitis disease activity index. However, its role in the diagnosis and management of acute pouchitis has not been thoroughly defined. The aim of this study is to review previously established cut-off values and contextualize the clinical utility of fecal calprotectin.

METHODS

Search of Medline, EMBASE, CENTRAL, and PubMed was performed. Articles were eligible if they measured fecal calprotectin in the setting of pouchitis in patients who underwent TPC with IPAA for UC. Risk of bias of the included studies was evaluated with the QUADAS-2.

RESULTS

From 117 relevant citations, seven studies with 256 patients (44.8% female, 39.88 years) met inclusion criteria. The pooled prevalence of pouchitis was 42%. The derived fecal calprotectin cut-off values ranged from 56 to 494 μg/g. The corresponding sensitivities and specificities ranged from 57 to 100% and 38 to 92%, respectively. The area under the curve was reported in three studies and ranged from 0.832 to 0.840.

CONCLUSION

Fecal calprotectin may be a reliable diagnostic tool for acute pouchitis in patients following TPC with IPAA for UC. The high sensitivity of fecal calprotectin for detection of pouchitis makes it a valuable test for ruling out pouchitis. When used in conjunction with other biomarkers, the high specificity offers value in ruling in pouchitis. However, given the complexity of this disease process, relying solely on biomarkers for diagnosis is currently unreasonable.