Pathogenesis of and unifying hypothesis for 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.

Normal Ileal Mucus Is Inadequate for Epithelial Protection in Ileal Pouch Mucosa

BACKGROUND

Clinical, nonspecific pouchitis is common after restorative proctocolectomy for ulcerative colitis, but its cause is unknown. A possible lack of protection for the ileal mucosa in its role as a reservoir for colonic-type bacteria may be the missing piece in defining the causes of pouchitis.

OBJECTIVE

The study aimed to review the causes of pouchitis and introduce the hypothesis that inadequate mucus protection in the pouch, combined with a predisposition to abnormal inflammation, is the most common cause of nonspecific pouchitis.

DATA SOURCES

Review of PubMed and MEDLINE for articles discussing pouchitis and intestinal mucus.

STUDY SELECTION

Studies published from 1960 to 2023. The main search terms were "pouchitis," and "intestinal mucus," whereas Boolean operators were used with multiple other terms to refine the search. Duplicates and case reports were excluded.

MAIN OUTCOME MEASURES

Current theories about the cause of pouchitis, descriptions of the role of mucus in the physiology of intestinal protection, and evidence of the effects of lack of mucus on mucosal inflammation.

RESULTS

The crossreference of "intestinal mucus" with "pouchitis" produced 9 references, none of which discussed the role of mucus in the development of pouchitis. Crossing "intestinal mucus" with "pouch" resulted in 32 articles, combining "pouchitis" with "barrier function" yielded 37 articles, and "pouchitis" with "permeability" yielded only 8 articles. No article discussed the mucus coat as a barrier to bacterial invasion of the epithelium or mentioned inadequate mucus as a factor in pouchitis. However, an ileal pouch produces a colonic environment in the small bowel, and the ileum lacks the mucus protection needed for this sort of environment. This predisposes pouch mucosa to bacterial invasion and chronic microscopic inflammation that may promote clinical pouchitis in patients prone to an autoimmune response.

LIMITATIONS

No prior studies address inadequate mucus protection and the origin of proctitis. There is no objective way of measuring the autoimmune tendency in patients with ulcerative colitis.

CONCLUSIONS

Studies of intestinal mucus in the ileal pouch and its association with pouchitis are warranted.

Use of Biologics for the Treatment of Inflammatory Conditions of the Pouch: A Systematic Review

BACKGROUND

Patients with medically-refractory ulcerative colitis or advanced neoplasia are often offered an ileal-pouch-anal anastomosis to restore bowel continuity. However, up to 50% of patients can suffer from inflammatory conditions of the pouch, some of which require biological therapy to treat. The aim of this study was to determine the efficacy of each biological agent for the treatment of inflammatory conditions of the pouch.

MATERIALS AND METHODS

A comprehensive literature search was performed in the major databases from inception through February 11, 2020, for studies assessing the efficacy of biologics in chronic antibiotic-refractory pouchitis (CARP) and Crohn's disease (CD) of the pouch. Both prospective and retrospective studies were included. The primary outcomes of interest were complete and partial responses were defined within each study. χ 2 test was used to compare variables.

RESULTS

Thirty-four studies were included in the systematic review and meta-analysis. Sixteen studies (N=247) evaluated the use of infliximab (IFX), showing complete response in 50.7% and partial response in 28.1% for CARP, and complete response in 66.7% and partial response in 20% for CD of the pouch. Seven studies (n=107) assessed the efficacy of adalimumab. For CARP, 33.3% of patients had a complete response, and 38.1% had a partial response, whereas for CD of the pouch, 47.7% experienced a complete response, and 24.6% had a partial response. Three studies (n=78) reported outcomes with the use of ustekinumab, showing 50% complete response and 3.8% partial response for CARP. For the CD of the pouch, 5.8% had a complete response and 78.8% had a partial response. Seven studies (n=151) reported the efficacy of vedolizumab, showing 28.4% complete response and 43.2% partial response in patients with CARP, whereas 63% of patients experienced partial response in CD of the pouch. IFX had higher rates of complete response in CARP compared with adalimumab ( P =0.04) and compared with vedolizumab ( P =0.005), but not compared with ustekinumab ( P =0.95). There were no new safety signals reported in any of the studies.

CONCLUSIONS

Biologics are safe and efficacious in the treatment of chronic, refractory inflammatory conditions of the pouch. IFX seems to be more efficacious than adalimumab and vedolizumab for CARP. Further prospective, head-to-head evaluations are needed to compare biological therapies in the treatment of CARP and CD of the pouch.

Pouchitis Is Associated with Paneth Cell Dysfunction and Ameliorated by Exogenous Lysosome in a Rat Model Undergoing Ileal Pouch Anal Anastomosis

BACKGROUND

Pouchitis is a common complication of restorative proctocolectomy and ileal pouch anal anastomosis (IPAA) for ulcerative colitis (UC), significantly affecting the postoperative quality of life. Paneth cells play an important role in the maintenance of gut homeostasis. This study aimed to investigate the role of Paneth cells in the pathogenesis of pouchitis.

METHOD

Endoscopic biopsies from the pouch body and terminal ileum of UC patients undergoing IPAA with or without pouchitis were obtained to analyze Paneth cell function. Acute pouchitis was induced with 5% dextran sulfate sodium (DSS) for seven consecutive days in a rat model of IPAA. The Paneth cell morphology was examined by immunofluorescence and electron microscopy. The effect of exogenous lysozyme supplementation on pouchitis was also investigated. The fecal microbiota profile after DSS and lysozyme treatment was determined by 16s rRNA ITS2 sequence analysis.

RESULT

Abnormal mucosal lysozyme expression was observed in patients with pouchitis. The rat model of pouchitis showed increased pouch inflammation, increased CD3+ and CD45+ T cell infiltration, and decreased tight junction proteins, including ZO-1 and Occludin. There is a significant deficiency of Paneth cell-derived lysozyme granules in the rat model of pouchitis. Supplementation with exogenous lysozyme significantly ameliorated pouchitis, lowering the levels of inflammatory cytokines such as TNF-α and IL-6 in the pouch tissue. 16s rRNA analysis revealed a higher Lachnospiraceae level after lysosome treatment.

CONCLUSIONS

Paneth cell dysfunction is prominent in patients and rat models of pouchitis and may be one of its causes. The decrease in Lachnospiraceae, a characteristic of dysbiosis in pouchitis, could be reserved by lysosome treatment. Lysozyme supplementation shows promise as a novel treatment strategy for pouchitis.

The emerging role of the small intestinal microbiota in human health and disease

The human gut microbiota continues to demonstrate its importance in human health and disease, largely owing to the countless number of studies investigating the fecal microbiota. Underrepresented in these studies, however, is the role played by microbial communities found in the small intestine, which, given the essential function of the small intestine in nutrient absorption, host metabolism, and immunity, is likely highly relevant. This review provides an overview of the methods used to study the microbiota composition and dynamics along different sections of the small intestine. Furthermore, it explores the role of the microbiota in facilitating the small intestine in its physiological functions and discusses how disruption of the microbial equilibrium can influence disease development. The evidence suggests that the small intestinal microbiota is an important regulator of human health and its characterization has the potential to greatly advance gut microbiome research and the development of novel disease diagnostics and therapeutics.

Prevention and Medical Treatment of Pouchitis In Ulcerative Colitis

Approximately 50% of patients who have undergone IPAA surgery for Ulcerative Colitis (UC) develop at least 1 episode of pouchitis. Patients with pouchitis have a wide range of symptoms, endoscopic and histologic features, disease course, and prognosis. To date, there are no universally accepted diagnostic criteria in terms of endoscopy and histology; though, semi-objective assessments to diagnose pouchitis in patients with ileal pouch- anal anastomosis (IPAA) have been proposed using composite scores such as the Pouchitis Triad, Heidelberg Pouchitis Activity Score and Pouchitis Disease Activity Index (PDAI). In a systematic review that included four randomized trials evaluating five agents for the treatment of acute pouchitis, ciprofloxacin was more effective at inducing remission as compared with metronidazole. Rifaximin was not more effective than placebo, while budesonide enemas and metronidazole were similarly effective for inducing remission of acute pouchitis. Patients with pouchitis relapsing more than three times per year are advised maintenance therapy, and guidelines recommend ciprofloxacin or the probiotic VSL#3. In patients with antibiotic-refractory pouchitis, secondary factors associated with an antibiotic-refractory course should be sought and treated. In this review, we will discuss the prevention and management of pouchitis in Ulcerative Colitis patients.

The relationship between preoperative T helper cytokines in the ileal mucosa and the pathogenesis of pouchitis

BACKGROUND

Although the etiology of pouchitis remains unknown, inflammatory cytokines are significantly associated with the pathogenesis of pouchitis. The cytokine responses that characterize inflammatory bowel diseases (IBD) are key pathogenic components of the disease. Although cytokine profiles in the colonic mucosa have been investigated in experimental colitis models or IBD patients, cytokine profiles in the ileal mucosa at colectomy have been rarely assessed.

AIM

To assess the relationship between pouchitis and T helper (Th) cytokines in the ileal mucosa collected at the time of colectomy and pouch construction.

METHODS

This retrospective study involved 68 consecutive patients from January 2004 to May 2011 who underwent ileal pouch-anal anastomosis for ulcerative colitis. Samples were obtained from the terminal ileum of resected specimens at time of total colectomy or subtotal colectomy. mRNA expression levels of Th cytokines (IFN-γ, IL-23A, IL-5, IL-13 and IL-17A) were determined.

RESULTS

Forty of 68 patients (58.8%) developed pouchitis. There was no association between IL-23A expression levels and incidence of pouchitis (p = 0.301). Patients with elevated IFN-γ had a significantly higher incidence of pouchitis compared with low IFN-γ patients (p = 0.043). Univariate analysis demonstrated a total dose of prednisolone > 7000 mg administered before colectomy (p = 0.04) and high IFN-γ expression (p = 0.02) were significant risk factors for pouchitis onset. In multivariate analysis, elevated IFN-γ messenger(m)RNA levels were significantly associated with pouchitis onset (p = 0.03).

CONCLUSION

IFN-γ expression in the normal ileal mucosa at the time of colectomy may be an important factor in the pathophysiology of pouchitis.

A Systematic Review of Fecal Microbiota Transplant for the Management of Pouchitis

Background

Manipulation of the pouch microbiota via fecal microbiota transplant (FMT) has been theorized to be a promising therapeutic approach for pouchitis. The goal of this systematic review was to summarize the available, high-quality data on the efficacy and safety of FMT for acute and chronic pouchitis.

Methods

A systematic electronic literature search was conducted on Embase, MEDLINE, Scopus, and Cochrane CENTRAL. Randomized controlled trials and observational studies that assessed the efficacy and safety of FMT for the treatment of acute and/or chronic pouchitis in patients with ulcerative colitis who underwent total proctocolectomy with ileal pouch-anal anastomosis were included.

Results

Four studies involving the use of FMT for chronic pouchitis were considered eligible for data extraction. No study involving the use of FMT for the management of acute pouchitis was identified. In 1 study, 3/5 (75%) patients achieved sustained clinical remission at 3 months. In the remaining 3 studies, 2/8, 1/11, and 1/5 patients achieved clinical response defined as a decrease in pouchitis disease activity index at least 3. Stool donor engraftment as determined by 16s rRNA gene sequencing occurred only in those patients with clinical response.

Conclusions

The 4 studies that met inclusion criteria for this systematic review indicate FMT is safe in chronic pouchitis, however largely not efficacious. These data are limited by study heterogeneity. Additional studies are required to guide the use of FMT in patients with acute and chronic pouchitis.

The Structure and Function of the Human Small Intestinal Microbiota: Current Understanding and Future Directions

Despite growing literature characterizing the fecal microbiome and its association with health and disease, few studies have analyzed the microbiome of the small intestine. Here, we examine what is known about the human small intestinal microbiota in terms of community structure and functional properties. We examine temporal dynamics of select bacterial populations in the small intestine, and the effects of dietary carbohydrates and fats on shaping these populations. We then evaluate dysbiosis in the small intestine in several human disease models, including small intestinal bacterial overgrowth, short-bowel syndrome, pouchitis, environmental enteric dysfunction, and irritable bowel syndrome. What is clear is that the bacterial biology, and mechanisms of bacteria-induced pathophysiology, are enormously broad and elegant in the small intestine. Studying the small intestinal microbiota is challenged by rapidly fluctuating environmental conditions in these intestinal segments, as well as the complexity of sample collection and bioinformatic analysis. Because the functionality of the digestive tract is determined primarily by the small intestine, efforts must be made to better characterize this unique and important microbial ecosystem.

Vedolizumab for chronic antibiotic-refractory pouchitis

Background

Chronic antibiotic-refractory pouchitis (CARP) is a complication of ileal pouch-anal anastomosis (IPAA), which poses a therapeutic challenge. Vedolizumab, a gut-selective monoclonal antibody to the α4β7 of integrin, has been used in such patients, but data on its efficacy are limited. Our aim was to assess the efficacy and safety of vedolizumab as induction therapy in CARP patients.

Methods

In this single-center, historic cohort, patients with CARP who received vedolizumab between January 2015 to June 2017 were identified and analysed. Patients were included if they had active pouchitis with a total of modified pouch disease activity index (mPDAI) score ≥5 or if unavailable clinician diagnosis of active pouchitis. Pre-treatment and at 3-month post-therapy pouchoscopy and clinical visits were used to calculate mPDAI.

Results

A total of 19 patients were included in the study. The mean age was 26.7 ± 12.8 years, with 10 (53%) males. Nine (47%) patients had been treated with anti-tumor necrosis factor (TNF) agents before colectomy and 10 (53%) had anti-TNFs after colectomy and IPAA. Six (32%) patients had improvement in the mPDAI symptom subscores (P = 0.031) and 14 (74%) had improvement in both endoscopic and total mPDAI scores with a median change of -2 units (both P = 0.031). Adverse events were noted only in two (11%) patients and four (21%) required surgery for CARP.

Conclusions

Our study suggests that vedolizumab has efficacy and can be safely used for CARP patients. Larger studies with a higher number of patients are required to confirm these findings.

Clinical Research on the Comprehensive Curative Effect of Acupuncture and Traditional Chinese Medicine for Pelvic Inflammatory Sequelae

Background

This randomized, controlled trial was designed to assess whether acupuncture plus an oral administration of Chinese herbal medicine provides greater relief of symptoms than oral administration of Chinese herbal medicine alone for treatment of pelvic inflammatory sequelae.

Material/Methods

Sixty-two patients ages 22 to 45 years with pelvic inflammatory sequelae were randomly assigned into one of 2 groups: an herbal group (n=30) and an herbal with acupuncture group (n=32). Both groups were treated for 3 courses of 3 months each.

Results

Significant improvement of clinical symptoms and signs of pelvic inflammatory sequelae occurred in both treatment groups. The total effective rate for the herbal group was 83.33%, and for the herbal with acupuncture group it was 100% (P=0.354 for difference between groups). During treatment, 5 patients had adverse reactions of nausea, loss of appetite, and diarrhea. After adjustment of the herb prescription, all adverse reactions disappeared.

Conclusions

Our results highlight the benefit of oral administration of Chinese herbal medicine along with acupuncture; this had a greater clinical curative effect rate than oral administration of Chinese herbal medicine alone when treating pelvic inflammatory sequelae.

Value of routine stool testing for pathogenic bacteria in the evaluation of symptomatic patients with ileal pouches

BACKGROUND

In symptomatic patients with an ileal pouch, stool studies are often sent to diagnose enteric pathogens. Aim of this study is to find the value of routine stool studies in the evaluation of symptomatic patients and the clinical implications of such pathogens in patients with ileal pouches.

METHODS

Consecutive ileal pouch-anal anastomosis (IPAA) patients who had stool tests out of a 2283-case registry from 2002 to 2015 were included in the study. Patients with positive stool cultures were compared with controls (symptomatic without positive stool culture) in a 1:4 ratio. Response to antibiotic therapy, recurrence rate and rate of hospitalization at 1 and 3 months were assessed.

RESULTS

A total of 643 (28%) had stool cultures done and only 1.7% (11/643) were found to be positive for stool cultures. Campylobacter spp. (45%) was the most common pathogen followed by Aeromonas spp. (36%). Non-smokers and patients without any antibiotic use in the last 3 months were found to have higher prevalence of positive stool cultures than controls (p < 0.001 and p = 0.023). Patients with pathogenic bacteria were found to have a higher risk of acute kidney injury (27.3% vs 4.5%, p = 0.049), hospitalization within 3 months of initial stool testing (36.4% vs 6.8%, p = 0.009) and mortality (18.2% vs 0%, p = 0.040). However, there were no statistically significant differences in the clinical outcomes in patients with positive stool cultures who received pathogen-directed therapy.

CONCLUSIONS

We found that the yield of stool tests for bacterial pathogens in symptomatic pouch patients was extremely low and the treatment of detected pathogens had a minimum impact on the disease course of pouchitis. The clinical utility of routine stool culture in those patients warrants further study.

Festschrift for Ronan O'Connell: pouchitis, ulcerative colitis and the microbiome

The hypothesis of altered bacterial communities contributing to the development of pouchitis began a scientific quest to link host mucosal factors, microbial metabolism and spatial structure of the colonic microbiome in ulcerative colitis, reaching its apotheosis with the integration of advanced spatial sampling with laser capture microdissection, mucin array profiling, molecular microbiology and next-generation sequencing technologies. This article, part of a festschrift, summarises the contributions of the O'Connell lab to the field of host-microbial interactions in inflammatory bowel disease.

Tripterygium wilfordii polyglycosidium ameliorates pouchitis induced by dextran sulfate sodium in rats

BACKGROUND

The aim of this study was to investigate the therapeutic effects of Tripterygium wilfordii polyglycosidium (TWP) to rats with dextran sulfate sodium (DSS)-induced pouchitis and its possible mechanism.

METHODS

Sprague-Dawley rats underwent surgery of ileal pouch anal anastomosis (IPAA) and pouchitis was induced by DSS. Rats were randomly divided into no intervention (NI), normal saline (NS) and TWP groups. Rats were lavaged with normal saline (3ml/day in NS group) or TWP (12mg/kg/day in TWP group) for 7days. General conditions of animals and histopathological examinations were evaluated. Interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF)-α mRNA expression was measured. Levels of occludin and Zo-1 proteins were measured by immunohistochemistry. In addition, ALT and AST were assessed.

RESULTS

TWP significantly attenuated the symptoms of pouchitis characterized by body weight loss, diarrhea, and bloody stool. Furthermore, TWP diminished histological damage compared with other groups. There was a significant reduction in levels of IL-1β, IL-6, and TNF-α, as well as an increase in IL-10 in the TWP group. The expression of tight junction proteins occludin and Zo-1 were increased in the TWP group. There were no statistical differences in serum ALT and AST among the three groups.

CONCLUSIONS

TWP significantly ameliorated pouchitis and inhibited the production of IL-1β, IL-6, and TNF-α as well as increased the levels of IL-10, occludin, and Zo-1 protein in rats. These findings suggest TWP might be a potential therapeutic agent for patients with pouchitis.

Review article: the pathogenesis of pouchitis

BACKGROUND

A total proctocolectomy followed by ileal pouch-anal anastomosis is a potentially curative surgery for ulcerative colitis or familial adenomatous polyposis. About 5-35% of patients with ulcerative colitis and 0-11% of patients with familial adenomatous polyposis develop subsequent inflammation of the ileal pouch termed pouchitis.

AIM

To provide a comprehensive analysis of the research studying the possible pathogenesis of pouchitis. The goals were to identify promising areas of investigation, to help focus clinicians, researchers and patients on how to better understand and then potentially manage ileal pouchitis, and to provide avenues for future research investigations.

METHODS

This review examined manuscripts from 1981 to 2015 that discussed and/or proposed hypotheses with supportive evidence for the potential underlying pathogenic mechanism for pouchitis.

RESULTS

The pathogenesis of pouchitis is not definitively understood, but various hypotheses have been proposed, including (i) recurrence of ulcerative colitis, (ii) dysbiosis of the ileal pouch microbiota, (iii) deprivation of nutritional short-chain fatty acids, (iv) mucosal ischaemia and oxygen-free radical injury, (v) host genetic susceptibility and (vi) immune dysregulation. However, none of these alone are able to fully explain pouchitis pathogenesis.

CONCLUSIONS

Pouchitis, similar to inflammatory bowel disease, is a complex disorder that is not caused by any one single factor. More likely, pouchitis occurs through a combination of both dysregulated host inflammatory mechanisms and interaction with luminal microbiota.

Detrimental effects for colonocytes of an increased exposure to luminal hydrogen sulfide: The adaptive response

Protein fermentation by the gut microbiota releases in the large intestine lumen various amino-acid derived metabolites. Among them, hydrogen sulfide (H2S) in excess has been suspected to be detrimental for colonic epithelium energy metabolism and DNA integrity. The first objective of this study was to evaluate in rats the epithelial response to an increased exposure to H2S. Experiments from colonocyte incubation and intra-colonic instillation indicate that low millimolar concentrations of the sulfide donor NaHS reversibly inhibited colonocyte mitochondrial oxygen consumption and increased gene expression of hypoxia inducible factor 1α (Hif-1α) together with inflammation-related genes namely inducible nitric oxide synthase (iNos) and interleukin-6 (Il-6). Additionally, rat colonocyte H2S detoxification capacity was severely impaired in the presence of nitric oxide. Based on the γH2AX ICW technique, NaHS did not induce DNA damage in colonocytes. Since H2S is notably produced by the gut microbiota from sulfur containing amino acids, the second objective of the study was to investigate the effects of a high protein diet (HPD) on large intestine luminal sulfide content and on the expression of genes involved in H2S detoxification in colonocytes. We found that HPD markedly increased H2S content in the large intestine but the concomitant increase of the content mass maintained the luminal sulfide concentration. HPD also provoked an increase of sulfide quinone reductase (Sqr) gene expression in colonocytes, indicating an adaptive response to increased H2S bacterial production. In conclusion, low millimolar NaHS concentration severely affects colonocyte respiration in association with increased expression of genes associated with intestinal inflammation. Although HPD increases the sulfide content of the large intestine, the colonic adaptive responses to this modification limit the epithelial exposure to this deleterious bacterial metabolite.

Use of Biologics in Pouchitis: A Systematic Review

Data about the effectiveness of biologics, including anti-tumor necrosis factor (TNF) therapy and anti-integrin strategies, in antibiotic refractory pouchitis or Crohn's disease-associated pouch complications are sparse. We performed a systematic review of the literature in Medline and Web of Science. All English language publications and meeting abstracts describing patients with pouchitis treated with anti-TNF or anti-integrin therapies were included. We identified a total of 17 papers and 2 abstracts, most of these retrospective case series, including a total of 192 patients treated either with infliximab (n=140) or adalimumab (n=52). No reports were found for anti-integrin therapies or other anti-TNF agents such as certolizumab pegol or golimumab. Because of the heterogeneity of the studies, small numbers of patients, differing cotreatments, and subjective outcome definitions, the exact efficacy of these biological therapies cannot be assessed in a combined fashion. Overall infliximab appears to have good clinical effectiveness in selected patients achieving up to 80% short-term and around 50% long-term response, whereas the few data available for adalimumab are not sufficient to draw valid conclusions. Larger prospectively collected multicenter data with clearly defined inclusion criteria and outcomes are necessary to better define the clinical value of anti-TNF therapy in patients with antibiotic refractory pouchitis or Crohn's-like complications of the pouch.

FK506-Binding Protein 5 mRNA Levels in Ileal Mucosa Are Associated with Pouchitis in Patients with Ulcerative Colitis

BACKGROUND

Although the pathogenesis of pouchitis is incompletely understood, steroid and FK506 therapy are significantly associated with pouchitis. These medical treatments are regulated by the FK506-binding protein (FKBP) 4 and FKBP5 genes.

AIM

This study aimed to evaluate the relationship between pouchitis and FKBP4 and FKBP5 mRNA expression in ileal mucosa at the time of colectomy.

METHODS

Ileal mucosa specimens were collected from 71 patients who underwent ileal pouch-anal anastomosis for ulcerative colitis. FKBP4 and FKBP5 mRNA expression was evaluated. The relationship between mRNA expression and clinicopathological factors, including developed pouchitis, was investigated.

RESULTS

Of these 71 patients, 25 (35.2 %) patients developed pouchitis in a mean duration of 20.2 months (range 0-68 months). FKBP4 mRNA levels in patients who received an immunomodulator were significantly higher than those in untreated patients (0.167 ± 0.060 vs 0.131 ± 0.065, p = 0.009). However, FKBP5 mRNA levels in patients who received a three-stage operation were significantly lower than those in the other patients (1.97 ± 1.15 vs 2.70 ± 1.12, p = 0.02). A total dose of prednisolone >9.4 g (HR 2.84, p = 0.02) before colectomy and FKBP5 mRNA level higher than the median (HR 4.49, p = 0.01) were identified as factors related to pouchitis.

CONCLUSIONS

FKBP5 mRNA levels in ileal mucosa at the time of colectomy are significantly associated with pouchitis and may be a predictive factor for developing pouchitis.

Cyclosporine A regulates pro-inflammatory cytokine production in ulcerative colitis

Crohn's disease (CD) and ulcerative colitis (UC) are the two major forms of inflammatory bowel diseases (IBD), which are defined as relapsing inflammations of the gastrointestinal tract. Cyclosporine A (CsA) is a potential rescue treatment to avoid colectomy in severe steroid-refractory UC patients. The molecular mechanism of action of CsA in UC is nevertheless still not well understood. The aim of this study was to investigate the effect of CsA on a possible modulation of cytokine production by peripheral blood mononuclear cells (PBMCs) of controls and patients with UC or CD. Upon CsA treatment, analyses of cytokine levels revealed a significant reduction of IL-13 expression in PBMCs from patients with UC, whereas other cytokine expression levels remained unaffected. To address the question whether CsA treatment impinges on the induction of cell death, apoptosis assays were performed using CD4(+) T cells from peripheral blood of patients suffering from either UC or CD. It became clear that CsA treatment resulted in a specific induction of apoptosis in samples from controls and patients with UC but not with CD. Apoptosis induction was not mediated via the mitochondrial apoptosis pathway. The present data support the concept that CsA treatment modulates pro-inflammatory cytokine production and T cell survival in UC via the induction of apoptosis and might therefore help to explain the clinical efficacy of CsA in patients with UC.

Role of intestinal bacteria in the pathogenesis of pouchitis

Pouchitis is a common complication seen in patients with ulcerative colitis who undergo total proctocolectomy with ileal pouch anal anastomosis. Bacteria seem to play an important role in the development of pouchitis, although this role is not well defined. Because technology has advanced, we are able to apply molecular techniques to describe the structure and function of the pouch microbial community. In recent years, several studies have been performed comparing the pouch microbiota in patients with ulcerative colitis with healthy pouches and pouchitis. Many of these studies have suggested that pouchitis is characterized by dysbiosis and/or decreased microbial diversity. There has not been a clear pattern identifying a pathogenic organism or a group of organisms responsible for pouchitis. This review summarizes recent studies exploring the pouch microbiota in health and disease, the relationship of bacterial metabolites and pouchitis, and the role of antibiotics and probiotics for the treatment and prevention of pouchitis.

Synchronous cytomegalovirus and Clostridium difficile infection of the pouch: a trigger for chronic pouchitis?

Pouchitis occurs in up to one half of patients after restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). Cytomegalovirus (CMV) and Clostridium difficile are among the commonest secondary identifiable etiologies. A 17-year-old male with ulcerative colitis underwent IPAA due to refractory disease. Nine months later he experienced bloody diarrhea and fever. Laboratory testing and endoscopy confirmed pouch inflammation. Testing for C. difficile toxins A and B was positive. Histology revealed affluent inclusion bodies and immunohistochemistry detected reactivity against CMV protein. Treatment with metronidazole and vancomycin offered partial improvement, whereas the addition of gancyclovir led to a successful recovery. One month after completion of treatment symptoms recurred. Repeat testing precluded an identifiable infectious cause and the diagnosis of idiopathic chronic pouchitis was established. The patient is currently on maintenance treatment with the probiotic compound VSL#3.

Pouchitis: what every gastroenterologist needs to know

Pouchitis is the most common complication among patients with ulcerative colitis who have undergone restorative proctocolectomy with ileal pouch-anal anastomosis. Pouchitis is actually a spectrum of diseases that vary in etiology, pathogenesis, phenotype, and clinical course. Although initial acute episodes typically respond to antibiotic therapy, patients can become dependent on antibiotics or develop refractory disease. Many factors contribute to the course of refractory pouchitis, such as the use of nonsteroidal anti-inflammatory drugs, infection with Clostridium difficile, pouch ischemia, or concurrent immune-mediated disorders. Identification of these secondary factors can help direct therapy.

The effects of probiotics on barrier function and mucosal pouch microbiota during maintenance treatment for severe pouchitis in patients with ulcerative colitis

BACKGROUND

A total of 10-15% of patients with an ileoanal pouch develop severe pouchitis necessitating long-term use of antibiotics or pouch excision. Probiotics reduce the risk of recurrence of pouchitis, but mechanisms behind these effects are not fully understood.

AIM

To examine mucosal barrier function in pouchitis, before and after probiotic supplementation and to assess composition of mucosal pouch microbiota.

METHODS

Sixteen patients with severe pouchitis underwent endoscopy with biopsies of the pouch on three occasions: during active pouchitis; clinical remission by 4 weeks of antibiotics; after 8 weeks of subsequent probiotic supplementation (Ecologic 825, Winclove, Amsterdam, the Netherlands). Thirteen individuals with a healthy ileoanal pouch were sampled once as controls. Ussing chambers were used to assess transmucosal passage of Escherichia coli K12, permeability to horseradish peroxidase (HRP) and ⁵¹Cr-EDTA. Composition and diversity of the microbiota was analysed using Human Intestinal Tract Chip.

RESULTS

Pouchitis Disease Activity Index (PDAI) was significantly improved after antibiotic and probiotic supplementation. Escherichia coli K12 passage during active pouchitis [3.7 (3.4-8.5); median (IQR)] was significantly higher than in controls [1.7 (1.0-2.4); P < 0.01], did not change after antibiotic treatment [5.0 (3.3-7.1); P = ns], but was significantly reduced after subsequent probiotic supplementation [2.2 (1.7-3.3); P < 0.05]. No significant effects of antibiotics or probiotics were observed on composition of mucosal pouch microbiota; however, E. coli passage correlated with bacterial diversity (r = -0.40; P = 0.018). Microbial groups belonging to Bacteroidetes and Clostridium clusters IX, XI and XIVa were associated with healthy pouches.

CONCLUSIONS

Probiotics restored the mucosal barrier to E. coli and HRP in patients with pouchitis, a feasible factor in prevention of recurrence during maintenance treatment. Restored barrier function did not translate into significant changes in mucosal microbiota composition, but bacterial diversity correlated with barrier function.

Cytomegalovirus infection of the ileoanal pouch: clinical characteristics and outcomes

BACKGROUND

Up to 30% of cases of pouchitis are felt to have a secondary cause. Cytomegalovirus (CMV) may represent a possible etiopathological agent. Here, we report our experience with CMV involvement of the pouch, including risk factors, clinical features, and pouch outcomes in patients with inflammatory bowel disease after proctocolectomy with ileal pouch-anal anastomosis.

METHODS

The pathology database at Mayo Clinic in Rochester was searched between January 1995 and October 2012 for patients with a tissue diagnosis of CMV of the pouch following ileal pouch-anal anastomosis.

RESULTS

Seven patients with CMV inclusions of the pouch were identified. The median age was 35 (range, 10-53) years, and the majority were female (71%). Five patients (71%) were on immunosuppressive medications including 4 who had undergone orthotopic liver transplantation for primary sclerosing cholangitis. The clinical presentation was similar among all patients: the majority had diarrhea (86%), fever (71%), and abdominal pain (57%). All had mucosal inflammation, with 71% having focal ulcerations in the pouch and 60% having inflammatory changes in the prepouch ileum. All patients improved with ganciclovir. None required pouch excision or had recurrent CMV infection. Three patients had recurrent nonspecific pouchitis.

CONCLUSIONS

A high index of suspicion is needed to diagnose CMV of the pouch. An increase in stool frequency and fever in patients on immune suppression or in those who have failed empiric antibiotics should prompt assessment for CMV infection. Antiviral therapy seems to be effective, and postinfection pouch outcomes seem favorable, particularly in those presenting with their first episode of pouchitis.

Fecal lactoferrin: a noninvasive fecal biomarker for the diagnosis and surveillance of pouchitis

BACKGROUND

Fecal lactoferrin is a marker of intestinal inflammation and can be assessed with a simple qualitative immunochromatographic rapid test.

OBJECTIVE

We aimed to assess the sensitivity and specificity of the test in the diagnosis of pouchitis and evaluate its clinical utility in the surveillance of inflammation of the pouch after antibiotic therapy.

DESIGN

Between October 2005 and September 2009, we recruited a consecutive series of patients who had their ileal pouch examined under a general anesthetic. Distinctions between healthy and inflamed pouches were made by the use of the Pouch Disease Activity Index. Fecal samples were taken before biopsy of the pouch, and a clinician blinded to the examination findings performed the lactoferrin test. After antimicrobial treatment, a number of patients with pouchitis had a repeat examination and lactoferrin test.

RESULTS

There were 85 (41 male) patients. Median age was 42 (interquartile range, 36-49) years. Twenty-four patients had pouchitis. The test was positive in all 24 patients with pouchitis and 5 patients with a healthy pouch. The sensitivity and specificity of the test for pouchitis was 100% and 92%. The positive predictive value was 82%. In 7 patients who received antibiotic treatment for their pouchitis, the test was able to accurately predict the resolution and/or persistence of pouchitis.

CONCLUSION

The qualitative fecal lactoferrin rapid test is a sensitive method for the diagnosis and confirmation of resolution of pouchitis. The test provides clinicians with greater confidence in the prescription of antibiotics for suspected pouchitis and its surveillance.

Considerations and complications in patients undergoing ileal pouch anal anastomosis

Total proctocolectomy with ileal pouch anal anastomosis (IPAA) preserves fecal continence as an alternative to permanent end ileostomy in select patients with ulcerative colitis and familial adenomatous polyposis. The procedure is technically demanding, and surgical complications may arise. This article outlines both the early and late complications that can occur after IPAA, as well as the workup and management of these potentially morbid conditions.

Microbial pathways in colonic sulfur metabolism and links with health and disease

Sulfur is both crucial to life and a potential threat to health. While colonic sulfur metabolism mediated by eukaryotic cells is relatively well studied, much less is known about sulfur metabolism within gastrointestinal microbes. Sulfated compounds in the colon are either of inorganic (e.g., sulfates, sulfites) or organic (e.g., dietary amino acids and host mucins) origin. The most extensively studied of the microbes involved in colonic sulfur metabolism are the sulfate-reducing bacteria (SRB), which are common colonic inhabitants. Many other microbial pathways are likely to shape colonic sulfur metabolism as well as the composition and availability of sulfated compounds, and these interactions need to be examined in more detail. Hydrogen sulfide is the sulfur derivative that has attracted the most attention in the context of colonic health, and the extent to which it is detrimental or beneficial remains in debate. Several lines of evidence point to SRB or exogenous hydrogen sulfide as potential players in the etiology of intestinal disorders, inflammatory bowel diseases (IBDs) and colorectal cancer in particular. Generation of hydrogen sulfide via pathways other than dissimilatory sulfate reduction may be as, or more, important than those involving the SRB. We suggest here that a novel axis of research is to assess the effects of hydrogen sulfide in shaping colonic microbiome structure. Clearly, in-depth characterization of the microbial pathways involved in colonic sulfur metabolism is necessary for a better understanding of its contribution to colonic disorders and development of therapeutic strategies.

A shift from colon- to ileum-predominant bacteria in ileal-pouch feces following total proctocolectomy

BACKGROUND

We previously investigated fecal flora of the pouch after total proctocolectomy using terminal restriction fragment polymorphism analysis. Although the results of the cluster analysis demonstrated clearly that bacterial populations, including an unidentified bacteria generating a 213-bp PCR fragment, moved toward a colon-like community in the pouch, it did not track changes in the individual species of fecal bacteria.

AIMS

The aim of the present study was to estimate genome copy number of ten bacterial species, clusters, groups, or subgroups (including the bacteria generating 213-bp fragment in the previous study) in feces samples from pouches at various times following ileostomy closure.

METHODS

A total of 117 stool samples were collected from patients with ulcerative colitis after surgery as well as healthy volunteers. We used real-time polymerase chain reaction of the 16S rRNA gene to estimate genome copy numbers for the nine bacterial populations and the bacteria generating 213-bp fragment after identification by DNA sequencing.

RESULTS

We demonstrated a time-dependent increase in the number of anaerobic and colon-predominant bacteria (such as Clostridium coccoides, C. leptum, Bacteroides fragilis and Atopobium) present in proctocolectomy patients after stoma closure. In contrast, numbers of ileum-predominant bacterial species (such as Lactobacillus and Enterococcus faecalis) declined.

CONCLUSIONS

Our data confirm previous findings that fecal flora in the pouch after total proctocolectomy changes significantly, and further demonstrate that the number and diversity of ileal bacteria decreases while a more colon-like community develops. The present data are essential for the future analysis of pathological conditions in the ileal pouch.

Contributions of the microbial hydrogen economy to colonic homeostasis

Colonic gases are among the most tangible features of digestion, yet physicians are typically unable to offer long-term relief from clinical complaints of excessive gas. Studies characterizing colonic gases have linked changes in volume or composition with bowel disorders and shown hydrogen gas (H(2)), methane, hydrogen sulphide, and carbon dioxide to be by-products of the interplay between H(2)-producing fermentative bacteria and H(2) consumers (reductive acetogens, methanogenic archaea and sulphate-reducing bacteria [SRB]). Clinically, H(2) and methane measured in breath can indicate lactose and glucose intolerance, small intestinal bacterial overgrowth and IBS. Methane levels are increased in patients with constipation or IBS. Hydrogen sulphide is a by-product of H(2) metabolism by SRB, which are ubiquitous in the colonic mucosa. Although higher hydrogen sulphide and SRB levels have been detected in patients with IBD, and to a lesser extent in colorectal cancer, this colonic gas might have beneficial effects. Moreover, H(2) has been shown to have antioxidant properties and, in the healthy colon, physiological H(2) concentrations might protect the mucosa from oxidative insults, whereas an impaired H(2) economy might facilitate inflammation or carcinogenesis. Therefore, standardized breath gas measurements combined with ever-improving molecular methodologies could provide novel strategies to prevent, diagnose or manage numerous colonic disorders.

Increased crypt apoptosis is a feature of autoimmune-associated chronic antibiotic refractory pouchitis

BACKGROUND

Restorative proctocolectomy with IPAA is the surgical treatment of choice in patients with ulcerative colitis who require colectomy. Pouchitis is the most common long-term complication in patients with IPAA. While immune-mediated disorders frequently coexist with IBD, they appear to be associated with an increased risk for chronic antibiotic-refractory pouchitis.

OBJECTIVE

This study aimed to evaluate histologic features of autoimmune-associated chronic antibiotic-refractory pouchitis in comparison with controls and to assess their possible diagnostic utility.

DESIGN

Clinical definition for autoimmune-associated chronic pouchitis included 1) chronic antibiotic-refractory pouchitis with response only to corticosteroids, immunomodulators, or biologics; 2) positive serum autoantibodies, including antinuclear antibody, rheumatoid factor, and antimicrosomal antibody; and 3) concurrent immune-mediated disorders. Various histologic features of pouch biopsy specimens were evaluated.

SETTING

The investigation was conducted at a tertiary referral center.

PATIENTS

From our Pouchitis Registry, all eligible patients with autoimmune-associated pouchitis (n = 17) were included. The control groups included 16 patients with nonautoimmune-associated chronic antibiotic-refractory pouchitis, 39 with antibiotic-responsive pouchitis, and 19 patients with normal pouches. Various histologic features of pouch biopsy specimens were evaluated.

RESULTS

In comparison with the control groups, the autoimmune-associated pouchitis group showed a significant increase in deep crypt apoptosis (p < 0.001). It also showed more pyloric gland metaplasia in comparison with antibiotic-responsive pouchitis and normal pouches. With the use of apoptosis score which we developed as a diagnostic marker for autoimmune-associated chronic antibiotic-refractory pouchitis, we constructed a receiver operating curve and obtained an area-under-curve value of 0.89 (95% CI: 0.79, 0.99).

CONCLUSION

Increased deep crypt apoptosis is a distinctive histologic feature of autoimmune-associated chronic antibiotic-refractory pouchitis, and this feature may aid in the diagnosis and differential diagnosis in pouchitis.

Acute and chronic pouchitis--pathogenesis, diagnosis and treatment

Restorative proctocolectomy with ileal pouch-anal anastomosis has become the procedure of choice for the majority of patients with ulcerative colitis who require surgical treatment. Pouchitis, the most common long-term complication of the procedure, involves a spectrum of disease processes with heterogeneous risk factors, clinical features, disease courses and prognoses. In addition, clinical symptoms of pouchitis are not specific and often overlap with those of other inflammatory and functional pouch disorders, such as Crohn's disease of the pouch and irritable pouch syndrome. Pouchoscopy and biopsy, along with laboratory and radiographic evaluations, are often required for accurate diagnosis in patients with symptoms indicative of pouchitis. Dysbiosis has been implicated as a triggering factor for pouchitis, and concurrent infection with pathogens, such as Clostridium difficile, might contribute to disease relapse and exacerbation. Antibiotic therapy is the main treatment modality. However, the management of antibiotic-dependent and antibiotic-refractory pouchitis remains challenging. Secondary causes of pouchitis, such as ischaemia, NSAID use, the presence of concurrent primary sclerosing cholangitis and other systemic immune-mediated disorders, should be evaluated and properly managed.

Mechanisms of microbial hydrogen disposal in the human colon and implications for health and disease

In the human gastrointestinal tract, dietary components, including fiber, that reach the colon are fermented principally to short-chain fatty acids, hydrogen, and carbon dioxide. Microbial disposal of the hydrogen generated during anaerobic fermentation in the human colon is critical to optimal functioning of this ecosystem. However, our understanding of microbial hydrogenotrophy is fragmented and, at least as it occurs in the colon, is mostly theoretical in nature. Thorough investigation and integration of knowledge on the diversity of hydrogenotrophic microbes, their metabolic variation and activities as a functional group, as well as the nature of their interactions with fermentative bacteria, are necessary to understand hydrogen metabolism in the human colon. Here, we review the limited data available on the three major groups of H(2)-consuming microorganisms found in the human colon [methanogens, sulfate-reducing bacteria (SRB), and acetogens] as well as evidence that end products of their metabolism have an important impact on colonic health.

Pouchitis may increase the risk of dysplasia after restorative proctocolectomy in patients with ulcerative colitis

AIM

Dysplasia of the pouch mucosa after restorative proctocolectomy is rare. The aim of this study was to establish whether there is a correlation between pouchitis and dysplasia.

METHOD

A group of 276 patients treated for ulcerative colitis by restorative proctocolectomy between 1984 and 2009 was analysed. The presence or absence of pouchitis and dysplasia within the pouch was evaluated.

RESULTS

Inflammation was diagnosed in 66 (23.9%) patients, low-grade dysplasia in five (1.8%), high-grade dysplasia in three (1.1%), and cancer in one patient (0.4%). The prevalence of low-grade dysplasia was significantly higher in patients with inflammation than in those without (P < 0.04). High-grade dysplasia was significantly more frequent in pouchitis than in non-inflamed pouches (P < 0.01). Logistic regression analysis suggested that the occurrence of mucosal inflammation increased the risk of low grade dysplasia.

CONCLUSION

Patients with chronic pouchitis are at risk of dysplasia and require surveillance of the pouch.

Intestinal pouch complications in patients who underwent restorative proctocolectomy for ulcerative colitis and familial adenomatous polyposis in 1985-2008

Restorative proctocolectomy is considered a surgical treatment of choice in ulcerative colitis (UC) and familial adenomatous polyposis (FAP).The aim of the study was to evaluate postoperative complications in patients who underwent surgery for familial adenomatous polyposis and ulcerative colitis, on the basis of a retrospective data analysis.

MATERIAL AND METHODS

Data of 138 patients after restorative proctocolectomy performed between 1985 and 2008 were collected at routine follow-up visits in 2004-2008. We evaluated the presence of pouchitis, the degree of ileal pouch mucosa atrophy, the presence of ileal pouch mucosal metaplasia, the presence of ileal pouch malignancies, the necessity for diverting ileostomy, the necessity for pouch resection, and severe faecal incontinence.

RESULTS

Complications were observed in 45 (32.4%) patients. Thirty-seven patients developed pouchitis (26.6%). Low-degree dysplasia, severe dysplasia or malignancies were observed in total in 20 patients (14.4%). Six (4.3%) operated patients developed other analysed complications.

CONCLUSIONS

The most common complications of restorative proctocolectomy were dysplasia and pouchitis. The most common complication in patients operated for UC was pouchitis. The low observed incidence of intestinal pouchitis may be attributed to the implemented prophylaxis of inflammation. Dysplasia was the most common complication in patients undergoing proctocolectomy for FAP. Due to an increased risk of dysplastic lesions as compared with UC patients, careful endoscopic follow-up examinations are obligatory in this patient group. Other analysed complications were uncommon and were mostly a consequence of chronic pouchitis. Clinical symptoms of pouch-related problems were similar in both analysed groups.

Pharmacotherapy for acute pouchitis

OBJECTIVE

To review the current literature concerning the medical treatment of acute and chronic pouchitis.

DATA SOURCES

MEDLINE and International Pharmaceutical Abstracts were searched (both 1965-February 2011) using the following terms: pouchitis, Crohn's, ulcerative colitis, diagnosis, prophylaxis, and treatment. Bibliographies from key articles were also searched, and all pertinent articles were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All available primary literature published in English on treatment for pouchitis was considered, with controlled trials receiving highest priority.

DATA SYNTHESIS

Pouchitis occurs in up to 50% of ileal pouch-anal anastomosis (IPAA) patients with inflammatory bowel disease within 10 years of the procedure. Symptoms include abdominal pain, bloating, and fecal incontinence with frequent diarrhea. The diagnosis of pouchitis is usually made based on symptoms as well as endoscopic and histologic findings. Treatment of acute pouchitis includes antimicrobials such as ciprofloxacin, metronidazole, and rifaximin. If these fail, limited data suggest that oral budesonide, mesalamine, or infliximab may be effective treatments. Surgical revision may be necessary if medical treatments fail. Emerging evidence suggests that the probiotic compound VSL#3 may be effective in preventing the recurrence of pouchitis.

CONCLUSIONS

Pouchitis is a common complication of IPAA surgery. The strongest data suggest that antimicrobial therapy is an effective first-line treatment for acute pouchitis, and VSL#3 may be effective for prevention of recurrence.

The diameter of the ileal J-pouch-anal anastomosis as an important risk factor of pouchitis - clinical observations

BACKGROUND

Patients' quality of life after restorative proctocolectomy depends on the potential complications. Stricture of the ileal pouch-anal anastomosis is one of the complications following restorative proctocolectomy.

MATERIAL/METHODS

We analyzed the correlation between the diameter of the anastomosis and clinical parameters, including pouchitis disease activity index (PDAI), the activity of fecal M2-pyruvate kinase and maximum tolerable volume of the pouch. The study group consisted of 31 patients in whom covering ileostomy had been closed 72 ± 50 months before enrolement to the study. Restorative proctocolectomy for ulcerative colitis or familial adenomatous polyposis coli had been performed in this group.

RESULTS

The study did not show any correlation between the diameter of the anastomosis and primary indication for surgery, the time elapsed after restoration of the bowel continuity, the activity of fecal M2-pyruvate kinase, or maximum tolerable volume. However, meaningful correlations between the stricture of the anastomosis and the presence and activity of pouchitis, together with the ileal villi atrophy, were detected.

CONCLUSIONS

Stricture of the anastomosis appears to be an important factor increasing the incidence of pouchitis, and is independent of the underlying condition and time after the operation. Dilation of the anastomosis and prevention of stricture should constitute a permanent element of postoperative follow-up.

TLR2 and TLR4 up-regulation and colonization of the ileal mucosa by Clostridiaceae spp. in chronic/relapsing pouchitis

BACKGROUND

Chronic pouchitis, which can lead to pouch failure, occurs in approximately 5% of patients after restorative proctocolectomy for ulcerative colitis (UC). This work examined the interplay between the microbiota adherent to the ileal pouch mucosa and the mucosal immune system in chronic/relapsing pouchitis.

PATIENTS AND METHODS

Thirty-two consecutive patients attending our surgical gastroenterological department following restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) for UC were considered eligible candidates for this study. Biopsy samples of bacteria adherent to the mucosa were collected. TLR4 and TLR2 mucosal expression was measured by Real Time RT-PCR. Serum and mucosal IL-1β, IL-6, and TNF-α levels were assessed using immunometric assays. Fecal lactoferrin concentrations were determined by quantitative ELISA. After a median follow-up of 23 months (IQR 20-24 months) each patient underwent a global assessment of their clinical condition and disease activity status.

RESULTS

Six patients were diagnosed with relapsing/chronic pouchitis during the follow-up period. Mucosal TLR2 and TLR4 expression was higher in the chronic/relapsing pouchitis group than in the no or only one episode of pouchitis group (P = 0.036 and P = 0.016, respectively). The number of colony forming units (CFU) of mucosa-associated Clostridiaceae spp. was higher in the former than in the latter group (P = 0.031). Clostridiaceae were associated to a significant risk of chronic/relapsing pouchitis [OR: 14 (95% CI 0.887-224.021), P = 0.045].

CONCLUSION

Chronic/relapsing pouchitis is associated to higher mucosal TLR2 and TLR4 expression. Mucosal colonization by Clostridiaceae spp seems to play a role in the pathogenesis of chronic/relapsing pouchitis.

Perioperative factors during ileal pouch-anal anastomosis predict pouchitis

PURPOSE

Pouchitis is the most common complication of IPAA. Identifying factors predictive of pouchitis may improve outcomes by modifying contributing factors and enhancing patient selection. The most objective means for confirming pouchitis is by histology because the clinical and endoscopic diagnoses rely on more subjective assessments. The importance of histological pouchitis in the absence of clinical or endoscopic findings is unknown.

METHODS

Prospectively collected data on patients with IPAA and pouch surveillance were evaluated. Patients who developed pouchitis, defined as symptoms of pouchitis confirmed by endoscopic biopsy (group B) were compared with those without any episode of clinical, endoscopic, or histological pouchitis (group A) for pre- and intraoperative factors and outcomes. Asymptomatic patients with histological pouchitis on surveillance biopsies (group C) were further compared with group A. Patients with Crohn's disease were excluded.

RESULT

Of the 673 patients with pouch biopsies, 422 (62.7%) were in group A, 161 (23.9%) in group B, and 90 (13.4%) in group C. Mean follow-up was 9.8 (±5.1), 12.4 (±5.4), and 13. (±4.7) years. Of the 43 preoperative factors evaluated, those associated with group B included leukocytosis (P < .001), rheumatologic extraintestinal disease (P < .001), disease proximal to splenic flexure (P = .001), pulmonary comorbidity (P = .004), prior steroid use (P = .006), and age at operation and diagnosis (P = .018 and .021). Of the 10 intraoperative factors evaluated, pouchitis was associated with S-pouch reconstruction (P < .001), transfusion (P < .001), and 2-stage instead of 3-stage operation (P = .05), all surrogates for operative complexity. On multivariate analysis, pulmonary comorbidity (OR 3.38, 95% CI 1.62-7.07), disease proximal to splenic flexure (OR 2.37, 95% CI 1.18-4.77), extraintestinal disease manifestations (OR 1.6, 95% CI 1.01-2.54), and S-pouch reconstruction (OR 1.59, 95% CI 0.99 - 2.54) were associated with pouchitis. Patients in group B had worse outcomes, including more strictures (P = .015), bowel obstructions (P = .019), fistulas (P = .18), and lower quality of life (P < .001). Group C patients had the same outcomes as those in group A and the finding was not predicted by the above-mentioned parameters.

CONCLUSION

Patients with symptomatic, biopsy-confirmed pouchitis have worse long-term outcomes than those without pouchitis. This complication is associated with specific pre- and intraoperative factors. Histological pouchitis incidentally found on surveillance biopsy in asymptomatic patients is of no clinical relevance and does not influence outcome. Identification of these preoperative factors associated with the subsequent development of pouchitis will strengthen patient counseling and may facilitate risk stratification.

Small intestine and microbiota

PURPOSE OF REVIEW

To highlight the recent studies which have enhanced our appreciation of the composition of the microbiota in the human small intestine and its relevance to the health of the host.

RECENT FINDINGS

In the past number of years, the composition of the microorganisms present in our small intestines has been the subject of greater scrutiny than ever before. These investigations have been possible as a consequence of the development and utilization of new molecular tools which have revolutionized the field of microbial ecology and have focused predominantly on the small intestinal microbiota associated with pediatric celiac disease, inflammatory bowel disease, irritable bowel syndrome and pouchitis. The impact of invasive procedures, such as small bowel transplant, ileostomy and ileal pouch anal anastomosis, on the ileal microbiota has also been investigated.

SUMMARY

The ever greater appreciation of the link between the small intestinal microbiota and the health status of the host has the potential to lead to the development of new strategies to alter this microbiota in a targeted way to prevent or treat specific disorders.

NOD2/CARD15 mutations correlate with severe pouchitis after ileal pouch-anal anastomosis

PURPOSE

Pouchitis and Crohn's-like complications can plague patients after IPAA. NOD2 is an intracellular sensor for bacterial cell wall peptidoglycan. NOD2 mutations compromise host response to enteric bacteria and are increased in Crohn's disease. We hypothesize that IPAA patients with complications (Crohn's disease-like/pouchitis) have a higher rate of NOD2 mutations compared with asymptomatic IPAA patients.

METHODS

Patients were retrospectively subclassified into the following groups: 1) IPAA with Crohn's-like complications (n = 28, perianal fistula, pouch inlet stricture/upstream small-bowel disease, or biopsies showing granulomata) occurring at least 6 months after ileostomy closure; 2) IPAA with mild pouchitis (n = 33, ≤3 episodes/y for 2 consecutive years); 3) IPAA with severe pouchitis (n = 9, ≥4 episodes/y for 2 consecutive years or need for continuous antibiotics); 4) IPAA without complications or pouchitis (n = 37); 5) patients with Crohn's disease with colitis undergoing total proctocolectomy/ileostomy (n = 11); and 6) healthy controls (n = 269). The 3 NOD2 single-nucleotide polymorphism mutations (rs2066844, rs2066845, and rs2066847) previously identified as associated with Crohn's disease were genotyped using polymerase chain reaction. Groups were compared by use of χ with Yates continuity correction.

RESULTS

NOD2 mutations were found in 8.5% of healthy controls. NOD2 mutations were significantly higher in the severe pouchitis group (67%) compared with both asymptomatic IPAA (5.4%, P < .001) and IPAA with Crohn's disease-like complications (14.3%, P = .008) groups.

CONCLUSIONS

1) Asymptomatic IPAA patients have a low incidence of NOD2 mutations not significantly different from patients with mild pouchitis or healthy controls. 2) Patients with severe pouchitis had the highest incidence of NOD2 mutations, suggesting that this group may have a compromised host defense mechanism to enteric bacteria. 3) Patients with Crohn's-like complications after IPAA have a significantly lower incidence of NOD2 mutations than patients with severe pouchitis, suggesting a different genetic makeup in these 2 patient groups. Preoperative assessment of NOD2 in the equivocal IPAA candidate may predict severe pouchitis and might assist in preoperative surgical decision making.

Desulfovibrio bacterial species are increased in ulcerative colitis

BACKGROUND

Debate persists regarding the role of Desulfovibrio subspecies in ulcerative colitis. Combined microscopic and molecular techniques enable this issue to be investigated by allowing precise enumeration of specific bacterial species within the colonic mucous gel. The aim of this study was to combine laser capture microdissection and quantitative polymerase chain reaction to determine Desulfovibrio copy number in crypt-associated mucous gel in health and in acute and chronic ulcerative colitis.

METHODS

Colonic mucosal biopsies were harvested from healthy controls (n = 19) and patients with acute (n = 10) or chronic (n = 10) ulcerative colitis. Crypt-associated mucous gel was obtained by laser capture microdissection throughout the colon. Pan-bacterial 16S rRNA and Desulfovibrio copy number/mm were obtained by polymerase chain reaction at each locus. Bacterial copy numbers were interrogated for correlation with location and disease activity. Data were evaluated using a combination of ordinary linear methods and linear mixed-effects models to cater for multiple interactions.

RESULTS

Desulfovibrio positivity was significantly increased in acute and chronic ulcerative colitis at multiple levels within the colon, and after normalization with total bacterial signal, the relative Desulfovibrio load was increased in acute colitis compared with controls. Desulfovibrio counts did not significantly correlate with age, disease duration, or disease activity but interlevel correlations were found in adjacent colonic segments in the healthy control and chronic ulcerative colitis groups.

CONCLUSION

The presence of Desulfovibrio subspecies is increased in ulcerative colitis and the data presented suggest that these bacteria represent an increased percentage of the colonic microbiome in acute ulcerative colitis.

Secondary pouchitis: those with identifiable etiopathogenetic or triggering factors

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the surgical treatment of choice for the majority of patients with medically refractory ulcerative colitis (UC) or UC with dysplasia, or familial adenomatous polyposis. Various forms of pouchitis frequently occur after surgery. In fact, pouchitis is the most frequent long-term complication of IPAA in patients with UC, with a cumulative prevalence of up to 50%. The etiology and pathogenesis of pouchitis are not entirely clear. It is generally believed that the initiation and development of the disease process of pouchitis is associated with dysbiosis of pouch reservoir, as evidenced by a favorable response to antibiotic therapy. However, the majority of the patients do not show identifiable etiopathogenetic or triggering factors, therefore being labeled to have idiopathic pouchitis. In contrast, a subgroup of patients, particularly those with antibiotic-refractory pouchitis, may have obvious triggering factors for disease flare-up and progression and may be considered to have secondary pouchitis. Therefore, pouchitis can be classified on the basis of etiology into idiopathic and secondary causes. Approximately 20-30% of patients who present with chronic pouchitis have secondary identifiable and triggering factors, including cytomegalovirus or Clostridium difficile infection, ischemia, concurrent immune-mediated disorders, radiation, collagen deposition, and use of nonsteroidal anti-inflammatory drugs. Careful evaluation of these secondary causes of pouchitis that may contribute to resistance to antibiotics should be performed before the introduction of next-line medical therapy.

Pouchitis and pouch dysfunction

Restorative proctocolectomy with ileal pouch-anal anastomosis has become the surgical treatment of choice for most patients with ulcerative colitis who require surgery. Although the surgical procedure offers a cure in some patients, postoperative inflammatory and noninflammatory complications are common. Pouchitis is the most common long-term complication of the procedure. Pouchitis represents a spectrum of disease processes with heterogeneous risk factors, clinical phenotypes, natural history, and prognosis. Accurate diagnosis and classification are important for proper treatment and prognosis.

Pouchitis and pouch dysfunction

Restorative proctocolectomy with ileal pouch-anal anastomosis has become the surgical treatment of choice for most patients with ulcerative colitis who require surgery. Although the surgical procedure offers a cure in some patients, postoperative inflammatory and noninflammatory complications are common. Pouchitis is the most common long-term complication of the procedure. Pouchitis represents a spectrum of disease processes with heterogeneous risk factors, clinical phenotypes, natural history, and prognosis. Accurate diagnosis and classification are important for proper treatment and prognosis.

Emerging drugs for the treatment of ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic, relapsing inflammatory disorder of the colon for which the etiology is currently unknown. At present, strategies to treat UC are primarily targeted to control inflammation during active phases of disease as well as maintain remission during quiescence. As such, several unmet needs in the treatment of UC still remain. In recent years, basic research has led to the recognition of several key factors in the pathogenesis of UC, translating into the development of several novel therapeutic agents.

OBJECTIVE

The aim of this study is to review emerging therapies that may advance the treatment and improve the overall care of UC patients.

METHODS

An extensive literature search on published manuscripts and meeting proceedings has been performed to provide a comprehensive review of future drug therapies to treat UC.

RESULTS/CONCLUSION

The translational application of new discoveries in the basic understanding of UC pathogenesis is continuing and critical for the development of novel treatment strategies. Design of novel biologic therapies to treat UC has the challenge of addressing potential safety issues, while more traditional drugs should be further developed to facilitate patient compliance to treat this chronic, debilitating disease.