Prevalence of pouchitis in both ulcerative colitis and familial adenomatous polyposis: A systematic review and meta-analysis

Cellular and molecular mechanisms in the pathogenesis of pouchitis: more than just the microbiota

Pouchitis, defined as inflammation of the ileal pouch, is the most common complication following restorative proctocolectomy for refractory ulcerative colitis. Antibiotics remain the first line of therapy for pouchitis, but the majority of patients develop subsequent episodes and some are refractory to antibiotic therapy. This highlights the need for more effective treatment options and points to a more complex pathophysiology beyond the role of th pouch microbiome, similar to what is seen in inflammatory bowel disease. In this review, we outline the putative mechanisms of pouchitis, including genetic predisposition, microbiome alterations, dysfunction of the intestinal barrier and the immune system and review the available animal models of pouchitis. In addition, we introduce the concept of pouchitis as a possible transmural disease and discuss the potential role of non-immune cells, including stromal cells, in perpetuating inflammation and intestinal barrier dysfunction. We discuss future directions, implications for novel therapies and propose novel multicellular disease models that can better capture the complexity of pouchitis pathogenesis.

Comparative Effectiveness of Bile Acid Sequestrants and Antibiotics in the Management of Acute Pouchitis: A Matched Cohort Study from the United States

BACKGROUND AND AIMS

Bile acid sequestrants (BAS) are an emerging option for treatment of pouchitis. We aimed to compare BAS monotherapy, antibiotics, and combination therapy with both in the treatment of pouchitis after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC).

METHODS

We conducted a retrospective cohort study using the US-Collaborative TriNetX database to identify patients with acute pouchitis and UC. Treatment groups were divided into BAS (cholestyramine, colesevelam, colestipol), antibiotics (ciprofloxacin and/or metronidazole), and combination therapy of both BAS and antibiotics. Primary outcomes were failure of initial therapy (early relapse or nonresponse) and the development of recurrent pouchitis in the first 12 months after an initial episode of pouchitis.

RESULTS

Our analysis included 1,136 patients (mean age: 37.8 ± 15.4 years, and 45.9% female) of whom 727 (64%) were diagnosed with recurrent pouchitis. After adjusting for confounders by propensity-score matching, there was no significant difference in the odds of early relapse or nonresponse with BAS compared with antibiotic monotherapy (aOR: 0.74; 95% CI: 0.40-1.38; p = 0.34) or combination therapy (aOR: 0.94; 95% CI: 0.47-1.88; p = 0.86). Patients treated with BAS had a statistically significant lower recurrent pouchitis rate (aHR: 0.57; 95% CI: 0.42-0.79; p < 0.001) compared with patients treated with antibiotics. Patients treated with BAS had a statistically significant longer time (median: 225 days) to recurrent pouchitis (p < 0.001) compared to antibiotics (median: 99 days).

CONCLUSION

Using real-world evidence regarding treatment of pouchitis compared to standard antibiotic therapy, BAS monotherapy was not inferior for initial treatment response and significantly prolonged time to recurrent pouchitis.

Anti-integrin αvβ6 Antibodies Predict Pouchitis in Patients With Ulcerative Colitis After Restorative Proctocolectomy With Ileal Pouch-Anal Anastomosis

BACKGROUND

Pouchitis is the most common complication of restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis (IPAA) in patients with ulcerative colitis (UC). We previously reported the presence of anti-integrin αvβ6 antibodies in the serum of patients with UC. This study investigated the association between anti-integrin αvβ6 antibodies and the development of pouchitis in patients with UC.

METHODS

Serum levels of anti-integrin αvβ6 antibodies were measured by enzyme-linked immunosorbent assay in 16 patients with UC who underwent RPC with IPAA. Integrin αvβ6 expression in the colonic, terminal ileal, and pouch epithelium was examined using immunohistochemistry and western blot analysis.

RESULTS

Anti-integrin αvβ6 antibody levels in patients with UC were significantly decreased at 3, 9, and 12 months after RPC (P < .05). However, in patients who developed pouchitis, antibody levels remained high. The antibody levels at the time of RPC were significantly higher in patients who developed pouchitis compared to those who did not. Kaplan-Meier analysis revealed a significantly higher incidence of pouchitis in patients with antibody levels above the cutoff at the time of RPC. Although integrin αvβ6 was not expressed in the terminal ileal epithelium at the time of RPC, expression became positive in the pouch epithelium of patients with pouchitis.

CONCLUSIONS

The anti-integrin αvβ6 antibody levels in patients with UC were decreased after RPC but remained high in patients who developed pouchitis. The antibody levels at the time of RPC may serve as a potential prognostic biomarker for predicting the risk of pouchitis in patients with UC.

Pouchitis unveiled: exploring clinical features, diagnosis, and cutting-edge treatments

Last decades led to a revolution in the management of ulcerative colitis (UC), due to the development of novel advanced therapies and the identification of increasingly ambitious therapeutic goals. Nevertheless, a subset of patients, refractory to available therapies, still requires proctocolectomy with ileal pouch-anal anastomosis (IPAA). Pouchitis, an inflammatory condition of the ileal pouch, is the most common long-term complication of IPAA, affecting almost one-half of patients in the first 10 years after surgery. Symptoms of pouchitis include increased stool frequency, urgency, and abdominal discomfort, significantly affecting patients' quality of life. Traditionally the mainstay treatment of acute pouchitis involves the use of antibiotics, but one-fifth of patients develop chronic pouchitis (CP), which may be dependent or resistant to antibiotics, posing significant challenges in the management of this condition. Currently, there is still no consensus on the optimal management for CP, though recent progress in understanding the pathophysiology of pouchitis has paved the way for innovative therapeutic approaches, based on biological therapies and small molecules. This review aims to discuss the recent advanced therapies available for pouchitis and provide a comprehensive review on the topic to guide physicians in their clinical practice.

Multiomic analysis reveals cellular, transcriptomic and epigenetic changes in intestinal pouches of ulcerative colitis patients

Total proctocolectomy with ileal pouch anal anastomosis is the standard of care for patients with severe ulcerative colitis. We generated a cell-type-resolved transcriptional and epigenetic atlas of ileal pouches using scRNA-seq and scATAC-seq data from paired biopsy samples of the ileal pouch and the ileal segment above the pouch (pre-pouch) from patients (male=4, female=2), and paired biopsies of the terminal ileum and ascending colon from healthy individuals (male=3, female=3) serving as reference. Our study finds an additional population of absorptive and secretory epithelial cells within the pouch but not the pre-pouch. These pouch-specific enterocytes express a subset of colon-specific genes, including CEACAM5 and CD24. However, compared to normal colonocytes, expression of these genes is lower, and these enterocytes also express inflammatory and secretory genes while maintaining expression of some ileal-specific genes. This cell-type-resolved transcriptomic and epigenetic atlas of the ileal pouch establishes a reference for investigating pouch physiology and pathology.

Multiomic analysis reveals cellular, transcriptomic and epigenetic changes in intestinal pouches of ulcerative colitis patients

Total proctocolectomy with ileal pouch anal anastomosis is the standard of care for patients with severe ulcerative colitis. We generated a cell-type-resolved transcriptional and epigenetic atlas of ileal pouches using scRNA-seq and scATAC-seq data from paired biopsy samples of the ileal pouch and the ileal segment above the pouch (pre-pouch) from patients (male=4, female=2), and paired biopsies of the terminal ileum and ascending colon from healthy individuals (male=3, female=3) serving as reference. Our study finds previously uncharacterized populations of absorptive and secretory epithelial cells within the pouch but not the pre-pouch. These pouch-specific enterocytes express a subset of colon-specific genes, including CEACAM5 and CD24. However, compared to normal colonocytes, expression of these genes is lower, and these enterocytes also express inflammatory and secretory genes while maintaining expression of some ileal-specific genes. This cell-type-resolved transcriptomic and epigenetic atlas of the ileal pouch establishes a reference for investigating pouch physiology and pathology.

Risk Factors and Postoperative Outcomes in Pouchitis Following Restorative Proctocolectomy: An 18-Year Single-Center Study

Background/Objectives: Restorative proctocolectomy with ileo-anal pouch anastomosis (IPAA) remains the preferred surgical treatment for ulcerative colitis (UC). However, complications like pouchitis can occur. This study aimed to describe patients who underwent IPAA for inflammatory bowel disease (IBD) at Padua Hospital from 2005 to 2023 and identify risk factors for pouchitis. Secondary objectives included evaluating the effectiveness of biological therapy in chronic antibiotic-refractory pouchitis (CARP), Crohn’s disease of the pouch (CDP), and Crohn’s-like inflammation of the pouch (CDLPI), and assessing risk factors for pouch failure. Methods: This retrospective, observational study included 109 patients whose data were collected from medical records. Univariate logistic regression was used to analyze associations between preoperative and postoperative factors and outcomes such as acute pouchitis and pouch failure. The effectiveness of biological therapy was assessed by measuring changes in the Pouchitis Disease Activity Index (PDAI) and the Modified Pouchitis Disease Activity Index (mPDAI) over a 12-month treatment period. Results: Univariate logistic regression revealed significant associations between preoperative extraintestinal manifestations (OR 3.569, 95% CI 1.240–10.720), previous diagnosis of Crohn’s disease (OR 10.675, 95% CI 1.265–90.089), and transmural inflammation at cross-sectional imaging before surgery (OR 3.453, 95% CI 1.193–9.991) with an acute pouchitis risk. Pouch failure was significantly associated with a previous diagnosis of Crohn’s disease (OR 9.500, 95% CI 1.821–49.571) and post-surgical fistulas (OR 41.597, 95% CI 4.022–430.172). Biological therapy led to a significant reduction in the PDAI score in patients with CARP, decreasing from a median of 10 to 4 (p = 0.006). Similarly, in patients with CDP or CDLPI, the mPDAI score was significantly reduced from a median of 9 to 1 (p = 0.034), with remission achieved in 5/6 (83.3%) of these patients. Conclusions: This study provides valuable insights into the management of IPAA patients and highlights the importance of early identification and treatment of risk factors for pouchitis and failure. Biological therapy demonstrated significant effectiveness in reducing disease activity in patients with CARP, CDP, and CDLPI, suggesting its role as a crucial component in managing these complications.

Diet and Microbiota Modulation for Chronic Pouchitis: Evidence, Challenges, and Opportunities

Chronic pouchitis occurs in about 50% of patients undergoing a restorative proctocolectomy for ulcerative colitis. This affection represents a significant therapeutic challenge, particularly for symptomatic patients who do not respond to antibiotic treatments and biologic therapies. Several dietary approaches, including low FODMAP diets and the Mediterranean diet, have shown promising results in improving symptoms and disease burden. The rationale for dietary intervention lies in the reduction in inflammation and modulation of gut microbiota. However, conflicting results and methodological heterogeneity jeopardize the transition of these approaches from the field of research to clinical practice. Together with a nutritional approach, innovative methods of microbiota modulation, including probiotics and fecal microbiota transplantation, are emerging as safe and effective strategies in managing chronic pouchitis. This narrative review analyzes recent advancements in nutritional therapies and microbiota modulation as innovative and complementary approaches for managing chronic pouchitis. After examining microbiota modulation strategies, specifically the effectiveness of probiotics, prebiotics, and fecal microbiota transplantation in restoring microbial diversity and their potential role in alleviating symptoms, the review assesses the available clinical evidence concerning dietary interventions and their impact on gut microbiota. A comprehensive understanding of interventions aimed at modulating the microbiota is crucial for enhancing the effectiveness of conventional therapies. Such strategies may lead to significant improvements in patients' quality of life and their perception of the disease. However, the variability in microbiota composition, the use of restrictive diets, and the lack of standardized methods for evaluating these interventions remain significant challenges. Future research is essential to improve our understanding of the underlying mechanisms and optimize clinical application.

The Effect of Non-pooled Multidonor Faecal Microbiota Transplantation for Inducing Clinical Remission in Patients with Chronic Pouchitis: Results from a Multicentre, Randomised, Double-blinded, Placebo-controlled Trial [MicroPouch]

BACKGROUND AND AIMS

To investigate if treatment with non-pooled, multidonor faecal microbiota transplantation [FMT] for 4 weeks was superior to placebo to induce clinical remission in patients with chronic pouchitis.

METHODS

The study was a randomised, double-blinded, placebo-controlled study with a 4-week intervention period and 12-month follow-up. Eligible patients with chronic pouchitis were recruited from five Danish hospitals. Participants were randomised to non-pooled, multidonor FMT derived from four faecal donors, or placebo. Treatment was delivered daily by enema for 2 weeks, followed by every second day for 2 weeks. Disease severity was accessed at inclusion and 30-day follow-up, using the Pouchitis Disease Activity Index [PDAI]; PDAI <7 was considered equivalent to clinical remission. Faecal samples from participants and donors were analysed by shotgun metagenomic sequencing.

RESULTS

Inclusion was stopped after inclusion of 30 participants who were randomised 1:1 for treatment with FMT or placebo. There was no difference in participants achieving clinical remission between the two groups at 30-day follow-up, relative risk 1.0 (95% CI [0.55; 1.81]). Treatment with FMT resulted in a clinically relevant increase in adverse events compared with placebo, incidence rate ratio 1.67 (95% CI [1.10; 2.52]); no serious adverse events within either group. Faecal microbiota transplantation statistically significantly increased the similarity of participant faecal microbiome to the faecal donor microbiome at 30-day follow-up [p = 0.01], which was not seen after placebo.

CONCLUSIONS

Non-pooled, multidonor FMT was comparable to placebo in inducing clinical remission in patients with chronic pouchitis, but showed a clinically relevant increase in adverse events compared with placebo. ClincialTrials.gov number, NCT04100291.

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.

Diagnosis and Medical Treatment of Acute and Chronic Idiopathic Pouchitis in Inflammatory Bowel Disease

Despite the decreased rates in inflammatory bowel disease (IBD) colectomies due to high advances in therapeutic options, a significant number of patients still require proctocolectomy with ileal pouch-anal anastomosis (IPPA) for ulcerative colitis (UC). Pouchitis is the most common complication in these patients, where up to 60% develop one episode of pouchitis in the first two years after UC surgery with IPAA with severe negative impact on their quality of life. Acute cases usually respond well to antibiotics, but 15% of patients will still develop a refractory disease that requires the initiation of advanced immunosuppressive therapies. For chronic idiopathic pouchitis, current recommendations suggest using the same therapeutic options as for IBD in terms of biologics and small molecules. However, the available data are limited regarding the effectiveness of different biologics or small molecules for the management of this condition, and all evidences arise from case series and small studies. Vedolizumab is the only biologic agent that has received approval for the treatment of adult patients with moderately to severely active chronic refractory pouchitis. Despite the fact that IBD treatment is rapidly evolving with the development of novel molecules, the presence of pouchitis represents an exclusion criterion in these trials. Recommendations for the approach of these conditions range from low to very low certainty of evidence, resulting from small randomized controlled trials and case series studies. The current review focuses on the therapeutic management of idiopathic pouchitis.

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.

Ouch, my pouch! a clinician's guide to pouchitis

Pouchitis is defined as inflammation of the ileal pouch created during a restorative proctocolectomy with ileal pouch-anal anastomosis. Although the incidence of this inflammatory condition is high, the exact etiology often remains unclear and the management challenging. In this review, we summarize the clinical presentation, pathogenesis, diagnosis, and management of this common complication.

Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient

IMPORTANCE

The Gram-negative bacterium Bacteroides fragilis is a common member of the human gut microbiota that colonizes multiple host niches and can influence human physiology through a variety of mechanisms. Identification of genes that enable B. fragilis to grow across a range of host environments has been impeded in part by the relatively limited genetic tractability of this species. We have developed a high-throughput genetic resource for a B. fragilis strain isolated from a UC pouchitis patient. Bile acids limit microbial growth and are altered in abundance in UC pouches, where B. fragilis often blooms. Using this resource, we uncovered pathways and processes that impact B. fragilis fitness in bile and that may contribute to population expansions during bouts of gut inflammation.

Microbiota and mucosal gene expression of fecal microbiota transplantation or placebo treated patients with chronic pouchitis

Altered microbiota and impaired host immune function have been linked to the pathogenesis of pouchitis. We used 16S rRNA gene sequencing and RNA sequencing data from a previous randomized clinical trial (RCT) on fecal microbiota transplantation (FMT) therapy in 26 chronic pouchitis patients with one-year follow-up. We analyzed changes in both luminal and mucosal microbiota composition, as well as in host mucosal gene expression to gain insights into the host-microbiota interactions possibly underlying clinical outcomes of the patients. Antibiotic type and pattern of use were significant drivers of the luminal microbiota at baseline. Differential gene expression analysis indicated transition from ileal to colonic gene expression in the pouch, and upregulation in inflammation- and immune system-related pathways in the pouch. At 4 weeks, the non-relapsed FMT patients had a lower microbiota dissimilarity to the donor than the non-relapsed placebo patients (p = .02). While two FMT-treated patients showed a shift toward the donor's microbiota during the one-year follow-up, the overall FMT microbiota modulation effect was low. Patient's luminal and mucosal microbiota profiles were unstable in both FMT and placebo groups. Expression of the chemokine receptor CXCR4 was downregulated at 52 weeks compared to the baseline in the non-relapsed patients in both FMT and placebo groups. Microbiota modulation by FMT seems to be low in this patient group. The microbiota composition or alterations did not explain the relapse status of the patients. Some evidence for remission-related host gene expression pattern was found; specifically, CXCR4 expression may have a role in sustained remission.

DECIDE: Delphi Expert Consensus Statement on Inflammatory Bowel Disease Dysplasia Shared Management Decision-Making

BACKGROUND AND AIMS

Inflammatory bowel disease colitis-associated dysplasia is managed with either enhanced surveillance and endoscopic resection or prophylactic surgery. The rate of progression to cancer after a dysplasia diagnosis remains uncertain in many cases and patients have high thresholds for accepting proctocolectomy. Individualised discussion of management options is encouraged to take place between patients and their multidisciplinary teams for best outcomes. We aimed to develop a toolkit to support a structured, multidisciplinary and shared decision-making approach to discussions about dysplasia management options between clinicians and their patients.

METHODS

Evidence from systematic literature reviews, mixed-methods studies conducted with key stakeholders, and decision-making expert recommendations were consolidated to draft consensus statements by the DECIDE steering group. These were then subjected to an international, multidisciplinary modified electronic Delphi process until an a priori threshold of 80% agreement was achieved to establish consensus for each statement.

RESULTS

In all, 31 members [15 gastroenterologists, 14 colorectal surgeons and two nurse specialists] from nine countries formed the Delphi panel. We present the 18 consensus statements generated after two iterative rounds of anonymous voting.

CONCLUSIONS

By consolidating evidence for best practice using literature review and key stakeholder and decision-making expert consultation, we have developed international consensus recommendations to support health care professionals counselling patients on the management of high cancer risk colitis-associated dysplasia. The final toolkit includes clinician and patient decision aids to facilitate shared decision-making.

Sensitivity and specificity of diagnostic modalities in pouchitis: a systematic review and meta-analysis

Restorative proctocolectomy (RPC) is the most common surgical procedure to restore gastrointestinal continuity after surgical resection of the colon and rectum. Pouchitis is a common complication with several different modalities that can be used to aid diagnosis. This systematic review and meta-analysis aimed at exploring the sensitivity and specificity these diagnostic modalities. The medical literature was searched using MEDLINE, EMBASE and EMBASE classic and PubMed from 1978 to June 2022. We calculated descriptive statistics using sensitivity, specificity, and false-positive rate of the primary studies and also their positive and negative likelihood ratios, and their diagnostic odds ratios. The screen found 5477 records with 13 studies being included. Faecal lactoferrin was found to have the highest pooled sensitivity and specificity of 98% and 88% respectively with imaging modalities coming in second and faecal calprotectin third with pooled sensitivities and specificities of 87% and 79% and 74% and 81% respectively. Faecal biomarkers particularly lactoferrin and imaging modalities may have an important role to play in diagnosing pouchitis. Importantly due to delays in availability of pouchoscopy, our data supports early ordering of these tests to help delineate from other causes. Further studies are required with larger cohort sizes to further validate these tests.

A Systematic Review and Meta-analysis of Randomized Clinical Trials on the Prevention and Treatment of Pouchitis after Ileoanal Pouch Anastomosis

BACKGROUND

This systematic review explored different medications and methods for prevention and treatment of pouchitis after restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA).

METHODS

PubMed, Scopus, and Web of Science were searched for randomized clinical trials that assessed prevention or treatment of pouchitis. The systematic review was reported in line with updated 2020 PRISMA guidelines. Risk of bias in the trials included was assessed using the ROB-2 tool and certainty of evidence was assessed using GRADE. The main outcomes were the incidence of new pouchitis episodes in the preventative studies and resolution or improvement of active pouchitis in the treatment studies.

RESULTS

Fifteen randomized trials were included. A meta-analysis of 7 trials on probiotics revealed significantly lower odds of pouchitis with the use of probiotics (RR: 0.26, 95% CI: 0.16-0.42, I2 = 20%, p < 0.001) and similar odds of adverse effects to placebo (RR: 2.43, 95% CI: 0.11-55.9, I2 = 0, p = 0.579). One trial investigated the prophylactic role of allopurinol in preventing pouchitis and found a comparable incidence of pouchitis in the two groups (31% vs 28%; p = 0.73). Seven trials assessed different treatments for active pouchitis. One recorded the resolution of pouchitis in all patients treated with ciprofloxacin versus 67% treated with metronidazole. Both budesonide enema and oral metronidazole were associated with similar significant improvement in pouchitis (58.3% vs 50%, p = 0.67). Rifaximin, adalimumab, fecal microbiota transplantation, and bismuth carbomer foam enema were not effective in treating pouchitis.

CONCLUSIONS

Probiotics are effective in preventing pouchitis after IPAA. Antibiotics, including ciprofloxacin and metronidazole, are likely effective in treating active pouchitis.

Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient

Bacteroides fragilis comprises 1-5% of the gut microbiota in healthy humans but can expand to >50% of the population in ulcerative colitis (UC) patients experiencing inflammation. The mechanisms underlying such microbial blooms are poorly understood, but the gut of UC patients has physicochemical features that differ from healthy patients and likely impact microbial physiology. For example, levels of the secondary bile acid deoxycholate (DC) are highly reduced in the ileoanal J-pouch of UC colectomy patients. We isolated a B. fragilis strain from a UC patient with pouch inflammation (i.e. pouchitis) and developed it as a genetic model system to identify genes and pathways that are regulated by DC and that impact B. fragilis fitness in DC and crude bile. Treatment of B. fragilis with a physiologically relevant concentration of DC reduced cell growth and remodeled transcription of one-quarter of the genome. DC strongly induced expression of chaperones and select transcriptional regulators and efflux systems and downregulated protein synthesis genes. Using a barcoded collection of ≈50,000 unique insertional mutants, we further defined B. fragilis genes that contribute to fitness in media containing DC or crude bile. Genes impacting cell envelope functions including cardiolipin synthesis, cell surface glycosylation, and systems implicated in sodium-dependent bioenergetics were major bile acid fitness factors. As expected, there was limited overlap between transcriptionally regulated genes and genes that impacted fitness in bile when disrupted. Our study provides a genome-scale view of a B. fragilis bile response and genetic determinants of its fitness in DC and crude bile.

Nuances of Ileal Pouch-Anal Anastomosis in Familial Adenomatous Polyposis

BACKGROUND

Patients with familial adenomatous polyposis are sometimes treated with prophylactic or therapeutic proctocolectomy to either prevent or treat the almost inevitable colorectal cancer that develops in the numerous, early onset tubular adenomas to which they are prone. These patients are potential candidates for a restorative IPAA.

OBJECTIVE

This study aimed to highlight the particular nuances of ileal pouch-anal surgery faced by patients with familial adenomatous polyposis and point out the implications of the syndrome for patients who are candidates for an IPAA and the surgeons operating on them.

STUDY SELECTION

A literature search was performed on PubMed and MEDLINE using the terms "ulcerative colitis," "familial adenomatous polyposis," "surgery," and "ileal pouch-anal anastomosis."

CONCLUSIONS

As a result of a fundamental difference in pathophysiology, there are significant differences in demographics, presentation, surgical strategy, and sequelae of proctocolectomy and IPAA between familial adenomatous polyposis and ulcerative colitis. Proctocolectomy with IPAA in selected familial adenomatous polyposis patients can be performed in 1 stage, but their lack of symptoms means that any complications assume a greater significance. In polyposis patients, postoperative endoscopic surveillance of residual large intestine begins immediately, whereas surveillance of the pouch itself becomes increasingly important. Symptoms leading to a diagnosis of pouchitis are instead often due to structural and functional issues.

A systematic review and meta-analysis of the outcome of ileal pouch-anal anastomosis in patients with ulcerative colitis versus patients with familial adenomatous polyposis

BACKGROUND

Ileal pouch-anal anastomosis (IPAA) is commonly used to restore gastrointestinal continuity after surgical treatment of mucosal ulcerative colitis (MUC) and familial adenomatous polyposis (FAP). The aim of the present systematic review was to compare the outcomes of patients with MUC and patients with FAP who underwent IPAA.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant systematic review was performed. PubMed, Scopus, and Web of Science were searched through December 2021. Cohort and randomized studies were eligible for inclusion if they directly compared patients with MUC and FAP who underwent IPAA. The main outcome measures were pouch failure, complications, and need for pouch excision or revision. ROBINS-I tool was used to assess the risk of bias across the studies. A random-effect meta-analysis was conducted.

RESULTS

Twenty-three studies (9200 patients) were included in this meta-analysis. Seven thousand nine hundred fifty (86.4%) had MUC and 1250 (13.6%) had FAP. The median age of patients was 33.1 years. The male to female ratio was 1.4:1. MUC had higher odds of pouchitis (OR 3.9, 95% CI 2.8-5.4, p < 0.001), stricture (OR 1.82, 95% CI 1.25-2.65, p = 0.002), fistula (OR 1.74, 95% CI 1.18-2.54, p = 0.004), and total complications (OR 1.89, 95% CI 1.3-2.77, p < 0.001) as compared to FAP. Both groups had similar odds of pelvic sepsis, leakage, pouch failure, excision, revision, and fecal incontinence.

CONCLUSIONS

Although patients with MUC undergoing IPAA may be at a higher risk of developing complications, particularly pouchitis, stricture, and fistula; the ultimate and functional outcome of the pouch is similar to patients with FAP. Pouch failure, excision and revision were similar in the two groups.