Dysbiosis and pouchitis

Relationship between pouch microbiota and pouchitis following restorative proctocolectomy for ulcerative colitis

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) has become the surgical treatment of choice for many patients with medically refractory ulcerative colitis (UC) and familial adenomatous polyposis (FAP). UC patients with IPAA (UC-IPAA) are, nevertheless, susceptible to inflammatory and noninflammatory sequelae such as pouchitis, which is only rarely noted in FAP patients with IPAA. Pouchitis is the most frequent long-term complication of UC-IPAA patients, with a cumulative prevalence of up to 50%. Although the aetiology of pouchitis remains unclear, accumulating evidence suggests that a dysbiosis of the pouch microbiota and an abnormal mucosal immune response are implicated in its pathogenesis. Studies using culture and molecular techniques have detected a dysbiosis of the pouch microbiota in patients with pouchitis. Risk factors, genetic associations, and serological markers suggest that interactions between the host immune response and the pouch microbiota underlie the aetiology of this idiopathic inflammatory condition. This systematic review focuses on the dysbiosis of the microbiota that inhabit the pouch in UC and FAP patients and its interaction with the mucosal immune system. A meta-analysis was not attempted due to the highly heterogeneous microbiota composition and the different detection methods used by the various studies. Although no specific bacterial species, genus, or family has as yet been identified as pathogenic, there is evidence that a dysbiosis characterized by decreased gut microbiota diversity in UC-IPAA patients may, in genetically predisposed subjects, lead to aberrant mucosal immune regulation triggering an inflammatory process.

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 gut microflora and its variety of roles in health and disease

The intestinal microbiota is a complex community of microorganisms that colonizes the gastrointestinal tract. The composition of the intestinal microbiota and the number of microorganisms differ in dependency of the local environmental conditions. The intestinal microbiota has an important impact on the development of the intestinal architecture and function, it influences the development of the gut-associated immune system, and epithelial cell functions. One of the most important functions of the intestinal microbiota is the prevention of bacterial overgrowth and susceptibility to infection with enteropathogenic organisms. Additionally, the intestinale microbiota plays a crucial role in the development of the systemic immunity and has an important influence on the host nutrition and metabolism. However, in genetically predisposed hosts, the intestinal microbiota is involved in the pathophysiology of inflammatory bowel diseases and pouchitis. Additionally, recent studies suggest that there might be an inflammation triggering effect of the intestinal microbiota in necrotizing enterocolitis. Here, we give an overview of the intestinal microbiota and its variety of roles in health and disease.

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.

Bacteriology in the etiopathogenesis of pouchitis

BACKGROUND

Pouchitis is the most common long-term complication in ulcerative colitis that follows restorative proctocolectomy. Clinical evidence suggests that dysbiosis plays a key role in its pathogenesis.

METHODS

Current literature on the topic was reviewed. A therapeutic approach was proposed based on the literature along with personal experience from the subspecialty Pouchitis Clinic.

RESULTS

Pouchitis represents a disease spectrum in the reservoir, with ranging etiopathogenesis, clinical phenotypes, disease courses and prognoses. Dysbiosis plays a critical role in disease initiation and progress, with antibiotic therapy as the mainstay for treatment. On the other hand, superimposed infection from pathogens contributes to flare-up of the disease. Pouchitis can progress into an 'IBD-like' condition, requiring anti-inflammatory, immunomodulator or even biological therapy.

CONCLUSION

Pouchitis represents a unique form of IBD. Investigation on the evolution from an antibiotic-responsive phenotype to chronic antibiotic-refractory pouchitis may shed some light on the pathogenesis and therapeutic targets of IBD.

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.

Innate immune environment in ileal pouch mucosa: α5 defensin up-regulation as predictor of chronic/relapsing pouchitis

Defensins are small cationic peptides with antibacterial activity expressed in Paneth cells (α-defensins) or generally in intestinal epithelial cells (β-defensins) that have a profound effect on gut microbiota. Chronic pouchitis, which occurs in 5% of patients after restorative proctocolectomy and can cause pouch failure, is associated to a significant increase of Clostridiaceae spp. The aim of this study was to gain further insight in the pathogenesis of pouch dysbiosis by exploring defensin expression. Thirty-two consecutive patients coming for follow-up endoscopy were recruited. On pouch biopsies, we cultured bacteria adherent to the mucosa and determined α- and β-defensins and toll-like receptor-4 and -2 mRNA by quantitative real-time RT-PCR. Serum and mucosal levels of IL-1β, IL-6 and TNF-α were measured with immunometric assays. Faecal lactoferrin was analysed by quantitative ELISA. After a median follow-up of 23 (IQR 20-24) months, the patients were contacted for a reassessment of current and past disease activity. During the follow-up, chronic/relapsing pouchitis was diagnosed in six patients. The mucosal level of α-5 and α-6 defensins correlated with chronic/relapsing pouchitis onset (τ = 0.30, p = 0.034 and τ = 0.28, p = 0.053, respectively). High levels of α-5 defensin resulted to be predictive of chronic/relapsing pouchitis [AUC = 74% (95% CI = 53-89%), p = 0.052]. Patients with high levels of α-5 and α-6 defensins had earlier pouchitis relapses (p = 0.009 and p = 0.034, respectively). High levels of α-5 defensin were associated to a significant risk of chronic/relapsing pouchitis [OR = 10.6 (95% CI = 1.2-97.6), p = 0.027]. At multivariate analysis, the mucosal levels of α-5 defensin and the number of CFU of mucosa-associated Clostridiaceae spp resulted to be independent predictors of chronic/relapsing pouchitis [β = 0.46 (0.18), p = 0.024 and β = 0.44 (0.18), p = 0.027, respectively]. In conclusion, chronic/relapsing pouchitis is associated to increased expression of mucosal HD-5 and to increased antimicrobial activity against Escherichia coli. In patients with chronic/relapsing pouchitis, HD-5 and TLR-4 over-expression is likely to create a hostile environment against Enterobacteriaceae, thus favouring Clostridiaceae spp by decreasing competing bacteria families.

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.

Relationship between mucosa-associated microbiota and inflammatory parameters in the ileal pouch after restorative proctocolectomy for ulcerative colitis

BACKGROUND

Our aim was to assess the relationship between the ileal-pouch microbiota and inflammatory parameters in patients operated on for ulcerative colitis.

METHODS

In this cross-sectional study, 32 consecutive outpatients returning for follow-up endoscopy were recruited. Pouch biopsies were obtained during endoscopy for culture of bacteria adherent to the mucosa, histology, and analysis of local inflammation (IL-1β, IL-6, and TNFα by immunometric assay; and toll-like receptor [TLR] 2 and 4 mRNA by quantitative real-time PCR). Fecal samples were collected for analysis of lactoferrin by ELISA.

RESULTS

Granulocyte and monocyte mucosal infiltration correlated directly with mucosal Bacteriodiaceae spp. counts. Clostridiaceae spp. counts showed a direct correlation with mucosal ulceration and number of daily stools. In patients with pouchitis, Enterococcaceae spp. counts were less than in healthy patients. Enterobacteriaceae spp., Streptococcaceae spp. and Enterococcaceae spp. counts correlated inversely with immune cell infiltration. TLR-2 and TLR-4 mRNA, and mucosal levels of IL-1β levels all correlated directly with Veilonella spp. counts.

CONCLUSION

Bacteriodaceae spp. and, Clostridiaceae spp. may be associated with inflammation of the pouch mucosa. Conversely, Enterococcaceae spp., and possibly Enterobacteriaceae spp. and Streptococcaceae spp., may have an active role in maintaining immunologic homeostasis within the pouch mucosa.

The bacterial pathogenesis and treatment of pouchitis

Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis is the operation of choice for patients with ulcerative colitis. Pouchitis is the most common cause of pouch dysfunction. Although the pathogenesis of this disease is not well understood, bacteria have been implicated in the disease process. Numerous bacterial studies have been reported over the last 25 years with few unifying findings. In addition, many different treatments for pouchitis have been reported with varying results. Antibiotic treatment remains the most studied and is the mainstay of treatment. In this article we review the aetiology of pouchitis and the evidenced-based treatment options.

The bacteriology of pouchitis: a molecular phylogenetic analysis using 16S rRNA gene cloning and sequencing

OBJECTIVE

To identify, compare, and contrast the microbiota in patients with and without pouchitis after restorative proctocolectomy (RPC) for ulcerative colitis (UC) and familial adenomatous polyposis (FAP).

SUMMARY BACKGROUND DATA

Pouchitis is the most common complication following RPC. An abnormal host-microbial interaction has been implicated. We investigated the pouch microbiota in patients with and without pouchitis undergoing restorative proctocolectomy for UC and FAP.

METHODS

Mucosal pouch biopsies, taken from 16 UC (pouchitis 8) and 8 FAP (pouchitis 3) patients were analyzed to the species (or phylotype) level by cloning and sequencing of 3184 full-length bacterial 16S rRNA genes.

RESULTS

There was a significant increase in Proteobacteria (P = 0.019) and a significant decrease in Bacteroidetes (P = 0.001) and Faecalibacterium prausnitzii (P = 0.029) in the total UC compared with the total FAP cohort, but only limited differences were found between the UC nonpouchitis and pouchitis groups and the FAP pouchitis and nonpouchitis groups. Bacterial diversity in the FAP nonpouchitis group was significantly greater than in UC nonpouchitis (P = 0.019) and significantly greater in UC nonpouchitis compared with UC pouchitis (P = 0.009). No individual species or phylotype specifically associated with either UC or FAP pouchitis was found.

CONCLUSIONS

UC pouch patients have a different, less diverse, gut microbiota than FAP patients. A further reduction in bacterial diversity but no significant dysbiosis occurs in those with pouchitis. The study suggests that a dysbiosis occurs in the ileal pouch of UC RPC patients which predisposes to, but may not directly cause, pouchitis.

An assessment of bacterial dysbiosis in pouchitis using terminal restriction fragment length polymorphisms of 16S ribosomal DNA from pouch effluent microbiota

PURPOSE

Previous studies on dysbiosis and pouchitis using conventional culture techniques have been disappointing because of inherent limitations associated with the technique. This study was designed to use terminal restriction fragment length polymorphism to evaluate patients with and without pouchitis.

METHODS

Bacterial microbiota in 20 pouch patients (15 healthy and 5 with inflamed) were studied. DNA was extracted from feces, and polymerase chain reaction was performed using primers (V6-V8 region) that were modified at the 5' end with cyanine dyes. Amplicons were digested with merozoite surface protein-1 enzyme. The restricted fragments were analyzed by capillary electrophoresis, and the electrophenograms were studied. Electrophenograms provide information about operational taxonomic units, which correspond to specific organisms. Principal component analysis was performed to identify dominant and important operational taxonomic units in the 20 patients. Bacterial diversity and counts of these operational taxonomic units were compared in the two groups of patients.

RESULTS

Total bacterial diversity in patients with pouchitis was similar to that in patients with healthy pouches (16 (11-20) vs. 12 (9-13), P = 0.279). Using principal component analysis, 29 operational taxonomic units were found to be important. Bacterial counts of seven dominant organisms (operational taxonomic unit 79 (enterococci), 85 (Pantoea), 88 (Enterobacteriaceae), 90 (eubacteria), 91 (Pseudomonas), 146 (clostridia), and 148 (bacilli)) were similar in patients with pouchitis and those with a healthy pouch (P > 0.05). Seventeen (operational taxonomic unit 73 (Leptospira), 93 (Pseudoalteromonas), 96, 100 (Desulfosporosinus), 114, 121, 134, 137, 141 (Microcystis), 159, 174 (Methylobacter), 193 (uncultured proteobacteria), 232, 376, 381, 414, and 465) of the remaining 22 nondominant organisms were seen exclusively in patients with pouchitis. The majority of these organisms were novel.

CONCLUSION

Terminal restriction fragment length polymorphism can be used to identify candidate organisms that may be associated with pouchitis.

Confocal laser endomicroscopy for the detection of mucosal changes in ileal pouch after restorative proctocolectomy

BACKGROUND

Pouchitis and dysplasia may affect the reservoir after restorative proctocolectomy.

AIMS

To assess the suitability of confocal laser endomicroscopy for the in vivo diagnosis of mucosal changes in ileal pouch for ulcerative colitis and familial adenomatous polyposis.

METHODS

Standard endoscopy and endomicroscopy were performed in 18 pouches. Confocal images were scored for the presence of villous atrophy, inflammation, ulceration, colonic metaplasia and dysplasia. Targeted biopsies were taken. Endomicroscopic and histological findings were compared.

RESULTS

At standard endoscopy, the signs of pouchitis were recorded in 7/18 (38.9%) patients. At endomicroscopy, pathological features were found in 16/18 (88.9%), villous atrophy in 15/18 (83.3%), inflammation in 13/18 (72.2%), ulceration in 3/18 (16.7%), and colonic metaplasia in 12/18 (67.7%). No dysplasia was observed. At histology, abnormalities were present in 17/18 (94.4%): villous atrophy in 15/18 (83.3%), inflammation in 17/18 (94.4%), ulceration in 6/18 (33.3%), colonic metaplasia in 15/18 (83.3%). Morphological changes of the ileal pouch could be predicted with an accuracy of 94.4% (95% CI: 74.2-99.0). The k-value for intra- and interobserver agreement was 0.93 and 0.78, respectively.

CONCLUSIONS

Endomicroscopy may be helpful in the evaluation of morphologic changes in ileal pouch. The small size of the population sample requires further studies for the results to be confirmed.

Pathogenesis of and unifying hypothesis for idiopathic pouchitis

Ileal pouch-anal anastomosis is the procedure of choice in the surgical management of refractory ulcerative colitis. Pouchitis affects up to 60% of patients following ileal pouch-anal anastomosis for ulcerative colitis. It overlaps significantly with ulcerative colitis such that improvements in our understanding of one will impact considerably on the other. The symptoms are distressing and impinge significantly on patients' quality of life. Despite 30 years of scientific and clinical investigation, the pathogenesis of pouchitis is unknown; however, recent advances in molecular and cell biology make a synergistic hypothesis possible. This hypothesis links interaction between epithelial metaplasia, changes in luminal bacteria (in particular sulfate-reducing bacteria), and altered mucosal immunity. Specifically, colonic metaplasia supports colonization by sulfate-reducing bacteria that produce hydrogen sulfide. This causes mucosal depletion and subsequent inflammation. Although in most cases antibiotics lead to bacterial clearance and symptom resolution, immunogenetic subpopulations can develop a chronic refractory variant of pouchitis. The aims of this paper are to discuss proposed pathogenic mechanisms and to describe a novel mechanism that combines many hypotheses and explains several aspects of pouchitis. The implications for the management of both pouchitis and ulcerative colitis are discussed.

The human gut microbiome: implications for future health care

In their intestine, humans possess an "extended genome" of millions of microbial genes-the microbiome. Because this complex symbiosis influences host metabolism, physiology, and gene expression, it has been proposed that humans are complex biologic "superorganisms." Advances in microbiologic analysis and systems biology are now beginning to implicate the gut microbiome in the etiology of localized intestinal diseases such as the irritable bowel syndrome, inflammatory bowel disease, and colon cancer. These approaches also suggest possible links between the gut and previously unassociated systemic conditions such as type 2 diabetes and obesity. The elucidation of the intestinal microbiome is therefore likely to underpin future disease prevention strategies, personalized health care regimens, and the development of novel therapeutic interventions. This review summarizes the research that is defining our understanding of the intestinal microbiome and highlights future areas of research in gastroenterology and human health in which the intestinal microbiome will play a significant role.

Both preoperative perinuclear antineutrophil cytoplasmic antibody and anti-CBir1 expression in ulcerative colitis patients influence pouchitis development after ileal pouch-anal anastomosis

BACKGROUND & AIMS

Acute pouchitis (AP) and chronic pouchitis (CP) are common after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis. The aim of this study was to assess associations of preoperative perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti-CBir1 flagellin on AP or CP development.

METHODS

Patients were assessed prospectively for clinically and endoscopically proven AP (antibiotic responsive) or CP (antibiotic-dependent or refractory to antibiotic therapy). Sera from 238 patients were analyzed for ANCA and anti-CBir1 using an enzyme-linked immunosorbent assay. pANCA(+) patients were substratified into high-level (>100 EU/mL) and low-level (<100 EU/mL) groups.

RESULTS

After a median follow-up period of 47 months, 72 patients (30%) developed pouchitis. Pouchitis developed in 36% of pANCA(+) patients versus 16% of pANCA(-) patients (P = .005), 46% of anti-CBir1(+) patients versus 26% of anti-CBir1(-) patients (P = .02), and 54% of 35 pANCA(+)/anti-CBir1(+) patients versus 31% of 136 pANCA(+)/anti-CBir1(-) patients (P = .02). AP developed in 37 pANCA(+) patients (22%) versus 6 pANCA(-) patients (9%) (P = .02), and 12 anti-CBir1(+) patients (26%) versus 31 anti-CBir1(-) patients (16%) (P = .1). Although AP was not influenced by pANCA level, AP was seen in 38% of low-level pANCA(+)/anti-CBir1(+) patients versus 18% low-level pANCA(+)/anti-CBir1(-) patients (P = .03). CP was seen in 29% of high-level pANCA(+) patients versus 11% of low-level pANCA(+) patients (P = .03).

CONCLUSIONS

Both pANCA and anti-CBir1 expression are associated with pouchitis after IPAA. Anti-CBir1 increases the incidence of AP only in patients who have low-level pANCA expression, and increases the incidence of CP only in patients who have high-level pANCA expression. Diverse patterns of reactivity to microbial antigens may manifest as different forms of pouchitis after IPAA.

Possible role of human cytomegalovirus in pouchitis after proctocolectomy with ileal pouch-anal anastomosis in patients with ulcerative colitis

AIM: To detect the presence of human cytomegalovirus (HCMV) proteins and genes on the ileal pouch of patients with ulcerative colitis who have undergone proctocolectomy with ileal pouch-anal anastomosis (IPAA).

METHODS: Immunohistochemistry, polymerase chain reaction (PCR) and PCR sequencing methods were utilized to test the presence of HCMV in pouch specimens taken from 34 patients in 86 endoscopies.

RESULTS: HCMV genes and proteins were detected in samples from 12 (35.2%) patients. The rate of detection was significant in the endoscopies from patients diagnosed with pouchitis (5 of 12, 41.6%), according to the Japanese classification of pouchitis, in comparison to patients with normal pouch (7 of 62, 11.2%; P = 0.021). In all patients with pouchitis in which the HCMV was detected, it was the first episode of pouchitis. The virus was not detected in previous biopsies taken in normal endoscopies of these patients. During the follow-up, HCMV was detected in one patient with recurrent pouchitis and in 3 patients whose pouchitis episodes improved but whose positive endoscopic findings persisted.

CONCLUSION: HCMV can take part in the inflammatory process of the pouch in some patients with ulcerative colitis who have undergone proctocolectomy with IPAA.