Inflammation in ileal reservoirs: 'pouchitis'

Alteration in Urease-producing Bacteria in the Gut Microbiomes of Patients with Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Bacterial urease is a major virulence factor of human pathogens, and murine models have shown that it can contribute to the pathogenesis of inflammatory bowel diseases [IBD].

METHODS

The distribution of urease-producing bacteria in IBD was assessed using public faecal metagenomic data from various cohorts, including non-IBD controls [n = 55], patients with Crohn's disease [n = 291] or ulcerative colitis [n = 214], and patients with a pouch [n = 53]. The ureA gene and the taxonomic markers gyrA, rpoB, and recA were used to estimate the percentage of urease producers in each sample.

RESULTS

Levels of urease producers in patients with IBD and non-IBD controls were comparable. In non-IBD controls and most IBD patients, urease producers were primarily acetate-producing genera such as Blautia and Ruminococcus. A shift in the type of the dominant urease producers towards Proteobacteria and Bacilli was observed in a subset of all IBD subtypes, which correlated with faecal calprotectin levels in one cohort. Some patients with IBD had no detectable urease producers. In patients with a pouch, the probiotic-associated species Streptococcus thermophilus was more common as a main urease producer than in other IBD phenotypes, and it generally did not co-occur with other Bacilli or with Proteobacteria.

CONCLUSIONS

Unlike all non-IBD controls, patients with IBD often showed a shift towards Bacilli or Proteobacteria or a complete loss of urease production. Probiotics containing the species S. thermophilus may have a protective effect against colonisation by undesirable urease-producing bacteria in a subset of patients with a pouch.

Systematic review with meta-analysis: a history of smoking is not associated with a higher risk of pouchitis

BACKGROUND

Ileal pouch-anal anastomosis is a common surgical procedure in patients with an initial diagnosis of ulcerative colitis or indeterminate colitis. Tobacco smoking has been associated with protection from onset of ulcerative colitis. Smoking has been reported to be both a protective factor and a risk factor for the development of pouchitis.

AIM

To examine the influence of smoking on the risk of pouchitis.

METHODS

We identified 15 studies evaluating smoking as a risk factor for developing pouchitis in ulcerative colitis or indeterminate colitis patients with a history of ileal pouch-anal anastomosis in a systematic search performed from inception through May 4, 2020. A meta-analysis was then performed using a random-effects model to generate risk ratios (RR) and 95% confidence intervals (CI).

RESULTS

A history of smoking compared with never smoking was not associated with an increased risk of developing pouchitis (RR = 0.94, 95% CI 0.76-1.18, I²  = 73.7%). There was also no significant risk of pouchitis when comparing current smokers vs nonsmokers (RR = 0.93, 95% CI 0.70-1.24, I²  = 78.5%) and former smokers vs nonsmokers (RR = 0.96, 95% CI 0.74-1.23, I²  = 78.5%).

CONCLUSIONS

Smoking, past or present, is not associated with an increased risk for the development of pouchitis in patients with ulcerative colitis or indeterminate colitis.

An Update on the Medical Management of Inflammatory Pouch Complications

Total proctocolectomy with ileal pouch-anal anastomosis is the surgical procedure of choice for patients with medically-refractory ulcerative colitis or ulcerative colitis with associated dysplasia. Although most patients after ileal pouch-anal anastomosis experience good functional outcomes, a number of complications may develop. Of the long-term complications, pouchitis is most common. Although most respond to antibiotic treatment, some patients develop chronic pouchitis, leading to substantial morbidity and occasionally pouch failure. In patients with pouchitis who are not responsive to conventional antimicrobial therapy, secondary causes of chronic pouchitis need to be considered, including Crohn's disease of the pouch. In recent years, more literature has become available regarding the medical management of chronic pouchitis and Crohn's disease of the pouch, including the use of newer biologic agents. We herein provide a concise review on inflammatory complications involving the ileal pouch, including a focused approach to diagnosis and medical management.

Continent Ileostomy as an Alternative to End Ileostomy

Continent ileostomy (CI) was once a prevalent surgical technique for patients who required total proctocolectomy but then gave way to ileal pouch-anal anastomosis (IPAA) after 1980. Although IPAA has been the gold standard procedure preferred by most patients when total proctocolectomy is required, due to its imitation of physiological function of rectum and preserved function of anus, various complications have been observed with a relatively high rate of morbidity that could affect pouch longevity. Once serious complications such as pelvic abscesses and/or fistula occur, the pouch often needs to be removed. In addition, for some patients with a shortened small intestine or foreshortened mesentery, it is impossible for the ileal pouch to reach the pelvic floor, thus making the creation of an IPAA difficult. Previously, most of these patients would be referred for an end ileostomy, with an associated poor quality of life. In this circumstance, we propose that CI may deserve a reappraisal and serve as an alternative. In this article, we review the indications, contraindications, technique evolution, and outcomes of CI.

Management of Pouchitis and Other Common Complications of the Pouch

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) has become the preferred surgical treatment for refractory or complicated ulcerative colitis (UC) and familial adenomatous polyposis (FAP). Pouchitis is the most common complication of this procedure and can occur in about 50% of patients. Treatment of pouchitis depends on the phenotype of disease. Pouchitis can be classified as acute, chronic/refractory, or secondary pouchitis, which includes pouchitis occurring due to Crohn's disease (CD). CD of the pouch is becoming an increasingly recognized problem, and management is challenging. This article reviews the literature and offers treatment recommendations regarding management of pouchitis and CD of the pouch.

PROBIOTIC APPROACHES FOR TARGETING INFLAMMATORY BOWEL DISEASE: AN UPDATE ON ADVANCES AND OPPORTUNITIES IN MANAGING THE DISEASE

Various commensal enteric and pathogenic bacteria may be involved in the pathogenesis of inflammatory bowel diseases (IBDs), a chronic condition with a pathogenic background that involves both immunogenetic and environmental factors. IBDs comprising of Crohn's disease, and ulcerative colitis, and pauchitis are chronic inflammatory conditions, and known for causing disturbed homeostatic balance among the intestinal immune compartment, gut epithelium and microbiome. An increasing trend of IBDs in incidence, prevalence, and severity has been reported during recent years. Probiotic strains have been reported to manage the IBDs and related pathologies, and hence are current hot topics of research for their potential to manage metabolic diseases as well as various immunopathologies. However, the probiotics industry will need to undergo a transformation, with increased focus on stringent manufacturing guidelines and high-quality clinical trials. This article reviews the present state of art of role of probiotic bacteria in reducing inflammation and strengthening the host immune system with reference to the management of IBDs. We infer that t healthcare will move beyond its prevailing focus on human physiology, and embrace the superorganism as a paradigm to understand and ameliorate IBDs.

Colonic phenotype of the ileum in Crohn's disease: a prospective study before and after ileocolonic resection

BACKGROUND

Colonic metaplasia has been described in pouchitis. In a prospective study, we investigated whether colonic phenotype may develop in Crohn's disease (CD) ileum. The expression of sulfomucins (colonic mucin), sialomucins, and CD10 (small intestine mucin and phenotype) was evaluated before and after ileocolonic resection for CD.

METHODS

From February 2007 to March 2010, 22 patients with CD undergoing surgery were enrolled. Clinical (Crohn's Disease Activity Index >150) and endoscopic recurrence (Rutgeerts score ≥1) rates were assessed at 6 and 12 months. Ileal samples were taken at surgery (T0), at 6 (T1), and 12 months (T2) for histology, histochemistry (High Iron Diamine-Alcian Blue), and immunohistochemistry (anti-CD10).

RESULTS

In 22 patients, recurrence was assessed at 6 and 12 months (clinical recurrence 9% and 18%; endoscopic recurrence 73% and 77%). In all 22 patients, ileal samples were taken at 6 and 12 months (involved area in patients with recurrence). In 19 of 22 (86.3%) patients, the involved ileum was also studied at surgery. At T0, T1, and T2, the expression of sialomucins and CD10 (small intestine mucin and phenotype) was comparable and higher (P < 0.0001) than the expression of sulfomucins (colonic mucin) (mean [range], T0:82 [35-100] versus 75 [0-100] versus 16 [0-50]; T1:96 [60-100] versus 94.7 [50-100] versus 3.89 [0-40]; T2:93.3 [60-100] versus 88.1 [25-100] versus 6.6 [0-40]). The expression of small-intestine mucin and phenotype was higher at T1 (P = 0.025) versus T0 (P = 0.026). Differently, the expression of colonic mucin was lower at T1 versus T0 (P = 0.027).

CONCLUSIONS

In CD, the ileum involved by severe/established lesions develops a "metaplastic" colonic mucosa phenotype. Differently, CD ileum with no lesions or with early recurrence maintains the "native" small intestine type mucin secretion and phenotype.

Ileal pouch symptoms do not correlate with inflammation of the pouch

BACKGROUND & AIMS

Pouchitis is the most common complication after ileal pouch-anal anastomosis (IPAA). However, symptoms are not specific. The Pouchitis Disease Activity Index (PDAI) and the Pouchitis Activity Score (PAS) have been used to diagnose pouchitis. We evaluated the correlation between the clinical components of these scores and endoscopic and histologic findings.

METHODS

We performed a cross-sectional study, analyzing data from 278 patients from Mount Sinai Hospital (Toronto, Canada) who had an IPAA. Patients underwent pouchoscopy with a biopsy, and data were collected on patients' clinical status. The PDAI and PAS were calculated for each subject. The Spearman rank correlation (ρ) statistical test was used to evaluate correlations between the PDAI scores and PAS, and between total scores and subscores.

RESULTS

The total PDAI scores and PAS scores were correlated; the clinical components of each correlated with the total score (ρ = 0.59 and ρ = 0.71, respectively). However, we observed a low level of correlation between clinical and endoscopic or histologic subscores, with ρ of 0.20 and 0.10, respectively, by PDAI, and ρ of 0.19 and 0.04, respectively, by PAS.

CONCLUSIONS

There is a low level of correlation between clinical and endoscopic and histologic subscores of patients with IPAA; clinical symptoms therefore might not reflect objective evidence of inflammation. These findings, along with evidence of correlation between total scores and clinical symptoms, indicate that these indices do not accurately identify patients with pouch inflammation. Further research is required to understand additional factors that contribute to clinical symptoms in the absence of objective signs of pouch inflammation.

Pouchitis: a practical guide

Up to 30% of patients with ulcerative colitis (UC) will require surgical management. The established surgical procedure of choice is colectomy with ileal pouch-anal anastomosis (IPAA) for most patients. Patients with UC who have undergone IPAA are prone to develop inflammatory and non-inflammatory complications. Up to 50% of patients can be expected to experience at least one episode of pouchitis, and most of these patients will experience at least one additional acute episode within 2 years. In other cases, pouchitis might follow a relapsing-remitting course or a chronically active course. The specific aetiology of pouchitis is unknown and the optimal means of diagnosis and classification of pouchitis is not completely agreed upon. Diagnosis of pouchitis based on symptoms alone has been shown to be non-specific due to the fact that symptoms can originate from a myriad of aetiologies, not necessarily inflammatory in nature. As a result, the diagnosis of pouchitis should generally be based on the appropriate constellation of symptoms, combined with endoscopic and histological assessment. Due to the frequently relapsing course of pouchitis, and the fact that the aetiology and pathogenesis are not entirely clear, the long-term management can sometimes be challenging. This review outlines the features suggestive of deviation from 'normal' pouch function and provides an approach to the optimal use of diagnostic modalities and medical therapies to treat pouchitis in its various forms.

Antibiotics and probiotics in chronic pouchitis: A comparative proteomic approach

AIM: To profile protein expression in mucosal biopsies from patients with chronic refractory pouchitis following antibiotic or probiotic treatment, using a comparative proteomic approach.

METHODS: Two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to characterize the changes related to antibiotic therapy in the protein expression profiles of biopsy samples from patients with chronic refractory pouchitis. The same proteomic approach was applied to identify differentially expressed proteins in the non-inflamed pouch before and after probiotic administration.

RESULTS: In the first set of 2D gels, 26 different proteins with at least 2-fold changes in their expression levels between the pouchitis condition and antibiotic-induced remission were identified. In the second set of analysis, the comparison between mucosal biopsy proteomes in the normal and probiotic-treated pouch resulted in 17 significantly differently expressed proteins. Of these, 8 exhibited the same pattern of deregulation as in the pouchitis/pouch remission group.

CONCLUSION: For the first time, 2D protein maps of mucosal biopsies from patients with ileal pouch-anal anastomosis were provided, and differentially expressed proteins following antibiotic/probiotic treatment were identified.

Bacterial community diversity in cultures derived from healthy and inflamed ileal pouches after restorative proctocolectomy

BACKGROUND

Pouchitis is believed to occur as a reaction to dysbiosis. In this study we assessed differences between mucosal bacterial communities cultured from noninflamed and inflamed ileal pouches.

METHODS

Thirty-two ileal pouch patients, 22 with ulcerative colitis (UC) and 10 with familial adenomatous polyposis (FAP), underwent symptomatic, endoscopic, and histological assessment. The Objective Pouchitis Score (OPS) and the Pouch Disease Activity Index (PDAI) were used to diagnose pouchitis. Seven UC patients had pouchitis (UC+), 15 had a noninflamed pouch (UC-), 9 had a noninflamed pouch (FAP-), and 1 FAP patient had pouchitis (FAP+). Biopsies taken from the ileal mucosa of the pouch were cultured under aerobic and anaerobic conditions. Following standardized DNA extraction a polymerase chain reaction (PCR) was performed to generate 16S rRNA gene products. A "fingerprint" of the bacterial community within each sample was created using terminal-restriction fragment length polymorphism (T-RFLP) profiling. Species richness and evenness were determined using T-RF band lengths and relative band intensities.

RESULTS

From the 64 DNA samples, 834 bands were detected, of which 179 represented different species (operational taxonomic units [OTUs]). The average species richness for the FAP-, FAP+, UC-, and UC+ groups was 26, 35, 23.9, and 29.6 per patient, with the average species diversity within the groups of 10.6, 29, 8.3, and 11.4, respectively. Similar trends were observed when the anaerobic and aerobic-derived bacterial groups were analyzed separately.

CONCLUSIONS

No significant differences were found between the bacterial cultures derived from any of the clinical groups or between pouchitis and nonpouchitis patients.

Pouchitis, similar to active ulcerative colitis, is associated with impaired butyrate oxidation by intestinal mucosa

BACKGROUND

Healthy colonic mucosa uses butyrate as the major energy source. In ulcerative colitis (UC) butyrate oxidation has been shown to be disturbed, but it remains unclear whether this is a primary defect. The aim of this study was to measure mucosal butyrate oxidation in UC (involved and noninvolved colon) and in pouchitis and to study the relationship with endoscopic as well as histological disease activity.

METHODS

Butyrate oxidation was measured in 73 UC patients, 22 pouchitis patients, and 112 controls (95 colon, 17 ileum) by incubating biopsies with 1 mM 14C-labeled Na-butyrate and measuring the released 14CO2.

RESULTS

Compared with that in normal colon, butyrate oxidation was significantly impaired in endoscopically active but not in quiescent disease or uninvolved colon segments. The severity of the metabolic defect was related to histological disease activity and decreased epithelial cell height. In active pouchitis, butyrate oxidation was significantly decreased compared with that in normal ileum and excluded pouches without inflammation. The histological pouchitis score correlated significantly with butyrate oxidation.

CONCLUSIONS

Active UC and pouchitis show the same inflammation-related metabolic defect. Our data suggest that the defect is a consequence of inflammation and that pouchitis is metabolically similar to active UC.

Ileal lesions in patients with ulcerative colitis after ileo-rectal anastomosis: Relationship with colonic metaplasia

AIM: To assess whether in ulcerative colitis (UC) patients with ileo-rectal anastomosis (IRA), ileal lesions may develop in the neo-terminal-ileum and their possible relation with phenotypic changes towards colonic epithelium.

METHODS: A total of 19 patients with IRA under regular follow up were enrolled, including 11 UC and 8 controls (6 Crohn’s disease, CD; 1 familial adenomatous polyposis, FAP; 1 colon cancer, colon K). Ileal lesions were identified by ileoscopy with biopsies taken from the ileum (involved and uninvolved) and from the rectal stump. Staining included HE and immunohistochemistry using monoclonal antibodies against colonic epithelial protein CEP (Das-1) and human tropomyosin isoform 5, hTM5 (CG3). Possible relation between development of colonic metaplasia and ileal lesions was investigated.

RESULTS: Stenosing adenocarcinoma of the rectal stump was detected in 1 UC patient. The neo-terminal ileum was therefore investigated in 10/11 UC patients. Ileal ulcers were detected in 7/10 UC, associated with colonic metaplasia in 4/7 (57.1%) and Das-1 and CG3 reactivity in 3/4 UC. In controls, recurrence occurred in 4/6 CD, associated with colonic metaplasia in 3/4 and reactivity with Das-1 and CG3 in 2/3.

CONCLUSION: Present findings suggest that in UC, ileal lesions associated with changes towards colonic epithelium may develop also after IRA. Changes of the ileal content after colectomy may contribute to the development of colonic metaplasia, leading to ileal lesions both in the pouch and in the neo-terminal ileum after IRA.

Proliferation of immature plasma cells in pouchitis mucosa in patients with ulcerative colitis

BACKGROUND

Pouchitis is the most common complication of restorative proctocolectomy in patients with ulcerative colitis (UC). The etiology of pouchitis is not known. We have previously reported the specific and significant proliferation of immature plasma lineage cells in the ulcer bases and inflamed mucosa of UC. In the present study we report the results of a phenotypic study of ileal pouch mucosa.

METHODS

Biopsy samples were taken from the ileal pouch of 22 patients with UC (12 with pouchitis, 10 with a normal pouch) and 5 patients with familial adenomatous polyposis (FAP) (with a normal pouch) who underwent restorative proctocolectomy, and normal ileum of 10 patients with UC yet to undergo pouch surgery. Frozen sections were cut from fixed samples and reacted with various lymphocyte markers and anti-Ki-67 antibodies. Ki-67+ cells, CD19+ cells, and CD138+ cells were significantly increased in the pouchitis mucosa of patients with UC.

RESULTS

Immunological double staining revealed significantly increased numbers of CD19+Ki-67+ cells and CD138+Ki-67+ cells in the pouchitis mucosa of patients with UC compared to noninflamed UC pouch, FAP pouch, and normal ileum of UC patients. The number of CD19+CD138+ cells was significantly increased in inflamed pouch mucosa. The increased number of CD19+CD138+ cells we observed represents proliferation of immature plasma cells. Moreover, the increase in labeling for Ki-67 among CD19 cells and CD138 cells suggests proliferative activity of these cells, consistent with their immaturity.

CONCLUSIONS

Proliferation of these immature plasma cells suggests the possibility of involvement of UC-derived abnormality in the pathogenesis of pouchitis.

Pouchitis atlas for objective endoscopic diagnosis

"Pouchitis" is a term for nonspecific mucosal inflammation of the pouch after total proctocolectomy and ileal pouch-anal anastomosis for ulcerative colitis. Pouchitis is the most frequent complication of the pelvic pouch at the late stage. To improve the accuracy of the pouchitis diagnosis, sets of clinical symptoms and endoscopic findings (with or without histology of biopsy samples) have previously been evaluated. Endoscopic findings are central to the diagnosis, and a universal consensus of various endoscopic findings must be the initial step toward an objective diagnosis of pouchitis. Since a proper signpost for the endoscopic evaluation of pouchitis has been absent, we developed this pouchitis atlas to minimize the diagnostic variation inherent among individual endoscopists. We also propose new criteria for the diagnosis of pouchitis: the Japanese criteria for diagnosis of pouchitis. These criteria are based on clinical symptoms and endoscopic findings that are clearly categorized in the atlas, and exclude infectious enteritis, anastomotic insufficiency, pelvic infection, anal dysfunction, and Crohn's disease. Advantages of the new criteria include ease of bedside diagnosis, without the calculation of points required by the other criteria for pouchitis. This pouchitis atlas, together with our new criteria, should contribute to the establishment of a clear-cut diagnosis for pouchitis and promote better evaluation and treatment of this novel intestinal inflammation.

Ileal pouch surgery for ulcerative colitis

Ulcerative colitis (UC) is a relapsing and remitting disease characterised by chronic mucosal and submucosal inflammation of the colon and rectum. Treatment may vary depending upon the extent and severity of inflammation. Broadly speaking medical treatments aim to induce and then maintain remission. Surgery is indicated for inflammatory disease that is refractory to medical treatment or in cases of neoplastic transformation. Approximately 25% of patients with UC ultimately require colectomy. Ileal pouch-anal anastomosis (IPAA) has become the standard of care for patients with ulcerative colitis who ultimately require colectomy. This review will examine indications for IPAA, patient selection, technical aspects of surgery, management of complications and long term outcome following this procedure.

Quality of life after proctocolectomy with ileoanal anastomosis for patients with ulcerative colitis

Ulcerative colitis, a chronic inflammatory disease of the rectal and colonic mucosa, affects approximately 250,000 to 500,000 people in the United States, with 30% to 40% of patients requiring some form of surgical intervention during the course of their disease. The predominant reason for total proctocolectomy is for symptoms refractory to currently available medical therapy. Less common reasons are dysplasia or cancer. The goal of colectomy is to prevent recurrence of systemic inflammatory disease. Consequently, surgery with total proctocolectomy and creation of an ileal J-pouch-anal anastomosis has become the procedure of choice for many patients without other therapeutic options. Health-related quality of life (QOL) in patients with severe ulcerative colitis is so poor that, after ileal J-pouch-anal anastomosis, QOL is considered to improve in most clinical studies (8 studies, improved QOL; 1 study, no change; 1 study, QOL worse than general population). However, QOL and bowel function after such surgery cannot be considered "normal" in all patients, because a substantial number still have problems with urgency, leakage, nocturnal soiling, sexual dysfunction, and pouchitis, and some require conversion to a permanent ileostomy after ileal J-pouch-anal anastomosis failure. Thus, despite the availability of ileal J-pouch-anal anastomosis, surgery does not always restore all aspects of QOL to normal.

Bacterial and fungal microbiota in relation to probiotic therapy (VSL#3) in pouchitis

BACKGROUND

The intestinal microbiota plays a critical role in the pathophysiology of pouchitis, a major complication after ileal pouch anal anastomosis in patients with ulcerative colitis. Recently, controlled trials have demonstrated that probiotics are effective in maintenance of remission in pouchitis patients. However, the mechanism by which therapy with probiotics works remains elusive. This study explores the role of the bacterial and fungal flora in a controlled trial for maintenance of remission in pouchitis patients with the probiotic VSL#3 compound.

METHODS

The mucosa associated pouch microbiota was investigated before and after therapy with VSL#3 by analysis of endoscopic biopsies using ribosomal DNA/RNA based community fingerprint analysis, clone libraries, real time polymerase chain reaction (PCR), and fluorescence in situ hybridisation. Patients were recruited from a placebo controlled remission maintenance trial with VSL#3.

RESULTS

Patients who developed pouchitis while treated with placebo had low bacterial and high fungal diversity. Bacterial diversity was increased and fungal diversity was reduced in patients in remission maintained with VSL#3 (p = 0.001). Real time PCR experiments demonstrated that VSL#3 increased the total number of bacterial cells (p = 0.002) and modified the spectrum of bacteria towards anaerobic species. Taxa specific clone libraries for Lactobacilli and Bifidobacteria showed that the richness and spectrum of these bacteria were altered under probiotic therapy.

CONCLUSIONS

Probiotic therapy with VSL#3 increases the total number of intestinal bacterial cells as well as the richness and diversity of the bacterial microbiota, especially the anaerobic flora. The diversity of the fungal flora is repressed. Restoration of the integrity of a "protective" intestinal mucosa related microbiota could therefore be a potential mechanism of probiotic bacteria in inflammatory barrier diseases of the lower gastrointestinal tract.

Revolution and evolution: 30 years of ileoanal pouch surgery

Ileal pouch-anal anastomosis (IPAA) has become the standard of care for the 25% of patients with ulcerative colitis who ultimately require colectomy. IPAA is favored by patients because it avoids the necessity for a long-term stoma. This review examines how 3 decades of experience with IPAA has molded current practice, highlighting 5- and 10-year follow-up of large series to determine durability and functional performance, in addition to causes of failure and the management of complications.

The impact of the fecal stream and stasis on immunologic reactions in ileal pouch after restorative proctocolectomy for ulcerative colitis: a prospective, pilot study

OBJECTIVE

The etiology of pouch inflammation after restorative proctocolectomy is unknown. The fecal stream and immunological reactions are potential pathological factors. This study was performed to examine the impact of the fecal stream and stasis on immunological reactions in the pouch.

METHODS

Patients who underwent a restorative proctocolectomy with a covering ileostomy for ulcerative colitis were studied. Mucosal biopsy specimens were obtained from both the pouch and the proximal ileum at the time of ileostomy closure, and 3, 6, and 12 months after ileostomy closure. As a control group, normal ileal biopsies were obtained from patients with colonic polyps.

RESULTS

At the time of ileostomy closure, mucosal interleukin-1beta, interleukin-6, interleukin-8, and tumor necrosis factor-alpha levels in the pouch and the proximal ileum were not significantly different from those in the normal control group. At 3 months after ileostomy closure, the mucosal cytokine levels in the pouch increased significantly compared with those at ileostomy closure, and their levels were significantly higher than those in the proximal ileum. At 6 and 12 months after ileostomy closure, the mucosal cytokine levels in the pouch did not change significantly compared with those at 3 months after ileostomy closure. The mucosal cytokine levels in the proximal ileum did not change significantly during the entire study.

CONCLUSIONS

The immunological reactions in the pouch occurred soon after ileostomy closure, and continued for at least 1 yr. The fecal stream and stasis play an important part in the pathogenesis of immunological reactions in the ileal pouch.

Human lymphocyte stimulation with pouchitis flora is greater than with flora from a healthy pouch but is suppressed by metronidazole

BACKGROUND/AIMS

The gut flora may play an important role in the pathogenesis of inflammatory bowel disease. An ileal reservoir or pouch can be created to replace the excised rectum after proctocolectomy. In patients with ulcerative colitis this is subject to inflammation and termed pouchitis. Using bacteria from patients the authors sought evidence for the presence rather than the identity of a pathogenic species in pouchitis, and for its absence in healthy pouches by the differential effect on lymphocyte proliferation.

METHODS

An ex vivo cell culture assay was used in which peripheral blood mononuclear cells or lamina propria mononuclear cells were cultured with sterile sonicates of gut flora from patients with or without pouchitis in the presence of antigen presenting cells.

RESULTS

Sonicated pouchitis flora produced a consistent and intense proliferation of the mononuclear cells but that produced by sonicates from healthy pouches was minimal (p = 0.012 or 0.018, peripheral blood or lamina propria mononuclear cells). Preparation of the sonicates with the antibiotic metronidazole abolished their stimulatory ability (p = 0.005, peripheral blood mononuclear cells). In separate assays neither direct addition of metronidazole nor of its hydroxy metabolite affected the mononuclear cells' proliferation with alternative stimuli.

CONCLUSIONS

These results strongly support a bacterial aetiology for pouchitis.

Pouchitis

Pouchitis is one of the commonest and most debilitating complications of a restorative proctocolectomy. The cause remains elusive, though a number of approaches have been shown to alleviate the condition. This review outlines current evidence relating to pouchitis, obtained from randomised and nonrandomised studies. Medline, the Bath Information Data Service (BIDS) and PubMed were searched using the keywords 'pouchitis' and 'inflammatory bowel disease'. In addition, articles were cross-referenced, and the abstracts of recent colorectal meetings studied.

CXC and CC chemokine expression in inflamed and noninflamed pelvic ileal pouch tissue

BACKGROUND AND AIMS

Pouchitis is the major long-term complication after ileal pouch-anal anastomosis (IPAA) in patients operated on for ulcerative colitis. The cause is unknown, but both the history of ulcerative colitis and increased bacterial concentration are important factors. Chemokines are mediators for the recruitment of inflammatory cells to the site of inflammation. This study examined the tissue expression of a panel of specific chemokines and the corresponding recruitment of inflammatory cells in IPAA tissue with and without inflammation and after antibiotic treatment.

PATIENTS AND METHODS

Biopsy specimens postoperatively from ulcerative colitis patients with IPAA were obtained by endoscopy. Biopsies were taken from 8 patients with noninflamed IPAA and from 14 patients with an episode of acute pouchitis, before and after antibiotic treatment. Biopsies were stained for CD68, CD3, elastase, eotaxin, IP-10, MCP-1, MCP-3, and IL-8 and analyzed by NIH Image analyzer.

RESULTS

Expression of IL-8, MCP-1, MCP-3, and IP-10 was significantly higher in pouchitis than normal pouch. The expression of MCP-1, MCP-3 and IP-10 were significantly lower after antibiotic treatment.

CONCLUSION

These data support the importance of chemokines for the leukocyte recruitment in pouch tissue during acute pouchitis.

Surgery for inflammatory bowel disease

Ulcerative colitis is potentially cured by total excision of the colon and rectum. Crohn's disease is an unremitting condition in which operations are frequently multiple and in which the minimum amount of bowel possible should be excised.

Tropomyosin expression in the ileal pouch: a relationship with the development of pouchitis in ulcerative colitis

OBJECTIVE

Human tropomyosin isoform 5 (hTM5) is a cytoskeletal protein expressed in normal epithelial cells, predominantly in the colon. An autoimmune response toward hTM5 has been reported in ulcerative colitis (UC). Whether hTM5 expression in the ileum is involved in pouchitis is unknown. We assessed hTM5 expression on ileal epithelial cells at surgery and subsequently on development of pouchitis in UC.

METHODS

In a prospective longitudinal study, 28 UC patients undergoing ileal pouch procedures were included. Biopsy samples were taken from the rectum at surgery, as well as from the ileal pouch at surgery and at 6 months. The specimens were stained by immunoperoxidase using the anti-hTM5 monoclonal antibody CG3. Pouchitis was assessed by the Pouchitis Disease Activity Index and hTM5 expression on a scale of 0-3.

RESULTS

At surgery, in rectal samples, hTM5 expression was strong in all epithelial cells including the luminal surface, whereas in ileal samples hTM5 was not expressed or focally expressed only in the goblet cells. At 6 months, the ileum was found to have undergone morphological changes, becoming similar to the colon and showing shortening or reduced number of villi. These changes were associated with a diffuse hTM5 staining in the goblet cells and in the nongoblet epithelial cells lining the crypts and the lumen. The hTM5 score was related to the Pouchitis Disease Activity Index at 6 months (r = 0.82; p = 0.01).

CONCLUSIONS

Expression of hTM5 shows a different pattern in the ileal pouch in UC after surgery. This event is associated with morphological changes of the ileum toward colonic epithelium, related to the development of pouchitis.

Probiotics for the treatment of postoperative complications following intestinal surgery

Probiotics are living micro-organisms that belong to the normal enteric flora and exert a beneficial effect on health and well-being. The rationale for the therapeutic use of probiotics in pouchitis (the most frequent long-term complication following pouch surgery for ulcerative colitis) and postoperative recurrence in Crohn's disease is based on convincing evidence suggesting a crucial role for the endogenous intestinal microflora in the pathogenesis of these conditions. Positive results have been obtained with the administration of highly concentrated probiotic preparations in preventing the onset and relapses of pouchitis. Further controlled studies are needed to establish the efficacy of probiotics in the prophylaxis of postoperative recurrences of Crohn's disease and in the treatment of mild pouchitis.

Short- and long-term outcomes of ileal pouch-anal anastomosis for ulcerative colitis

Ileal pouch-anal anastomosis was an important advancement in the treatment of ulcerative colitis. The aim of this study was to determine whether early complications of ileal pouch-anal anastomosis in patients with ulcerative colitis are associated with poor late functional results.

PATIENTS AND METHODS

Eighty patients were operated on from 1986 to 2000, 62 patients with ileostomy and 18 without. The early and late complications were recorded. Specific emphasis has been placed on the incidence of pouchitis with prolonged follow-up.

RESULTS

The ileostomy was closed an average of 9.2 months after the first operation. Fourteen patients were excluded from the long-term evaluation; 6 patients were lost to regular follow-up, 4 died, and 4 patients still have the ileostomy. Of the 4 patients that died, 1 died from surgical complications. Early complications after operation (41) occurred in 34 patients (42.5%). Late complications (29) occurred in 25 patients as follows: 16 had pouchitis, 3 associated with stenosis and 1 with sexual dysfunction; 5 had stenosis; and there was 1 case each of incisional hernia, ileoanal fistula, hepatic cancer, and endometriosis. Pouchitis occurred in 6 patients (9.8%) 1 year after ileal pouch-anal anastomosis, 9 (14.8%) after 3 years, 13 (21.3%) after 5 years, and 16 (26.2%) after more than 6 years. The mean daily stool frequency was 12 before and 5.8 after operation. One pouch was removed because of fistulas that appeared 2 years later.

CONCLUSIONS

Ileal pouch-anal anastomosis is associated with a considerable number of early complications. There was no correlation between pouchitis and severe disease, operation with or without ileostomy, or early postoperative complications. The incidence of pouchitis was directly proportional to duration of time of follow-up.

Long-term failure after restorative proctocolectomy for ulcerative colitis

OBJECTIVE

To establish the incidence and causes of late failure in patients undergoing restorative proctocolectomy for a preoperative diagnosis of ulcerative colitis was the objective of this investigation.

SUMMARY BACKGROUND DATA

Restorative proctocolectomy is the elective surgical procedure of choice for ulcerative colitis. Most patients have a satisfactory outcome but failures occur. The reasons and rates of early failure are well documented, but there is little information on long-term failure.

METHODS

A series of 634 patients (298 females, 336 males) underwent restorative proctocolectomy for inflammatory bowel disease between 1976-1997, with a mean follow-up of 85 +/- 58 months. Failure was defined as removal of the pouch or the need for an indefinite ileostomy. It was divided into early and late, occurring within 1 year or more than 1 year postoperatively. RESULTS There were 3 (0.5%) postoperative deaths, leaving 631 patients for analysis. Of these, 23 subsequently died (disseminated large bowel cancer, 12; unrelated causes, 9; related causes, 2). There were 61 (9.7%) failures (15 early [25%], 46 late [75%]) due to pelvic sepsis (32 [52%]: 7 early, 25 late), poor function (18 [30%]: 2 early, 16 late), pouchitis (7 [11%]: 2 early, 5 late) and miscellaneous (4, all early). A final diagnosis of Crohn's disease, type of reservoir (J,S), female gender, postoperative pelvic sepsis and a one-stage procedure were significantly associated with failure. Failure rate rose with time of follow-up from 9% at 5 years to 13% at 10 years.

CONCLUSIONS

Pelvic sepsis and poor function were the main reasons for later failure. Failure rates should be reported based on the duration of follow-up.

Diagnosis and treatment of pouchitis

Total proctocolectomy with ileal pouch-anal anastomosis is the surgical procedure of choice for the management of ulcerative colitis. Pouchitis, a non-specific inflammation of the ileal reservoir, is the most frequent complication that patients experience in the long-term. Diagnosis should be made on the basis of clinical, endoscopic and histological aspects. The Pouchitis Disease Activity Index (PDAI) represents an objective and reproducible scoring system for pouchitis: active pouchitis is defined as a score > or = 7 and remission as a score < 7. About 15% of patients develop a chronic disease. Treatment of pouchitis is empirical, and very few controlled studies have been carried out. Antibiotics, particularly metronidazole and ciprofloxacin, are the treatment of choice. Chronic pouchitis may benefit from a prolonged course of a combination of antibiotics. Highly concentrated probiotics are effective for both prevention of relapses and prevention of pouchitis onset. There is no convincing evidence of the efficacy of other therapeutic agents.

The role of endoscopy in the evaluation of pouches and ostomies

Patients with ileal pouches and ostomies present with management issues that are challenging to the clinician. Endoscopy plays a significant role in diagnosing and guiding therapy in such patients. Unfortunately, there are very few prospective studies that evaluates endoscopy in these situations. Nevertheless, it is clear that endoscopy remains a powerful tool that is important for diagnosis and therapy of complications unique to these surgical procedures. It seems prudent to advocate endoscopic cancer surveillance for patients with pouches and ostomies; however, it remains to be seen whether these efforts will ultimately have an impact on long-term patient morbidity and mortality.

Expression of cytokines, inducible nitric oxide synthase, and matrix metalloproteinases in pouchitis: effects of probiotic treatment

OBJECTIVE

The efficacy of probiotic organisms in the treatment of pouchitis has been reported. In the present study, we evaluated the tissue levels of pro- and anti-inflammatory cytokines, nitric oxide synthase, and matrix metalloproteinases in control and inflamed pouches before and after antibiotic and probiotic treatment of patients with acute pouchitis.

METHODS

Pouch biopsy samples were obtained from seven patients with pouchitis before and after antibiotic and probiotic treatment. Tissue samples from five patients with normal pouches were used as controls. Cytokines were determined by ELISA, matrix metalloproteinase activity was evaluated by zymograms, and nitric oxide synthase activity was determined by measuring arginine to citrulline conversion.

RESULTS

Tissue levels of tumor necrosis factor a increased (p < 0.01) in pouchitis relative to uninflamed pouches and reduced after antibiotic and probiotic treatment. Also, interferon y and interleukin 1alpha (IL-1alpha) augmented in pouchitis, but their increase did not reach statistical significance. The latter, however, were lower (p < 0.05) after treatment with the antibiotics and probiotics. Tissue levels of IL-4 and IL-10 were unchanged in inflamed pouches and unaffected by antibiotic treatment. However, IL-10 increased (p < 0.05) after probiotic treatment. Moreover, inflamed pouches had higher levels of inducible nitric oxide synthase and gelatinase activities, which decreased after treatment.

CONCLUSIONS

The ability of antibiotic and probiotic treatments to increase tissue levels of IL-10, at a higher level than those observed in control pouches, and to decrease, to levels present in control pouches, proinflammatory cytokine, inducible nitric oxide synthase, and matrix metalloproteinase activity may suggest a mechanism of action to explain the efficacy of this therapeutic regime in pouchitis.

Upregulation of Fas-Fas-L (CD95/CD95L)-mediated epithelial apoptosis--a putative role in pouchitis?

INTRODUCTION

Ileal pouch-anal anastomosis (IPAA) remains the gold standard for patients with refractory ulcerative colitis. Pouchitis causes considerable morbidity in 40% of patients with IPAA. This study examined the role of increased epithelial apoptosis in the etiology of pouchitis.

METHODS

Following ethical approval pouch biopsies taken from patients with a history of pouchitis were compared with age-matched controls from patients who were pouchitis free. Apoptosis was detected immunohistochemically using a monoclonal antibody (M30) and terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin end labeling (TUNEL). Villous atrophy was assessed histologically and correlated with levels of apoptosis. Epithelial Fas-ligand (L) was also assessed immunohistochemically.

RESULTS

A significant increase in TUNEL staining was seen at the epithelial but not at the lamina propria level for known pouchitis patients versus controls (0.091 vs 0.035; P < 0.01). Similarly, epithelial M30 immunoreactivity (0.225 vs 0.082; P < 0.05) and villous atrophy (0.035 vs 0.10; P < 0.05) were significantly increased in pouches with previous pouchitis when compared with normal pouches. Upregulation of Fas-L expression was characteristic of this epithelium. Mononuclear cells were strongly positive for Fas-L. Increased epithelial levels of apoptosis correlated with increased levels of villous atrophy.

CONCLUSIONS

Our data suggest a role for elevated Fas-Fas-L (CD95-CD95L)-mediated epithelial apoptosis in the etiology of pouchitis. Increased levels of villous atrophy may result from increased apoptosis and thereby predispose to infection by otherwise apathogenic organisms.

Long-term follow-up after ileoanal pouch procedure: algorithm for diagnosis, classification, and management of pouchitis

PURPOSE

Inflammation of the ileoanal pouch (pouchitis) is one of the main complications after restorative proctocolectomy, yet its cause remains poorly understood. A standardized definition and diagnostic procedures in pouchitis are lacking.

METHOD

We analyzed all cases of pouchitis occurring in a group of 308 patients (210 with ulcerative colitis, 98 with familial adenomatous polyposis) who took part in a prospective long-term follow-up program. The severity of pouchitis was measured using a pouchitis activity score (Heidelberg Pouchitis Activity Score). An algorithm for the classification and management of pouchitis was established which enables the clinician: 1) to determine the severity of pouchitis, 2) to differentiate between primary pouchitis and pouchitis caused by surgical complications (secondary pouchitis), and 3) to evaluate the course (acute vs. chronic (> 3 months)).

RESULTS

The median duration of follow-up was 48 (range, 13-119) months. At least one episode of pouchitis was diagnosed in 29 percent of patients with ulcerative colitis and in 2 percent of familial adenomatous polyposis patients. Secondary pouchitis occurred in 6 percent of ulcerative colitis patients and was cured by surgical treatment in 13 (87 percent) of 15 cases. Primary pouchitis was diagnosed in 23 percent of ulcerative colitis patients, including 6 percent of all ulcerative colitis patients with chronic primary pouchitis. The latter showed poor response to medical treatment. In one case multifocal high-grade dysplasia occurred. Histologic examination of the excised pouch identified a carcinoma originating from the ileal mucosa.

CONCLUSIONS

Ulcerative colitis patients after restorative proctocolectomy face a high risk of developing pouchitis. The algorithm used in this study was highly efficient in identifying patients with a secondary pouchitis who require surgical treatment and patients with chronic primary pouchitis. For the latter, long-term surveillance seems mandatory because of the risk of malignant transformation of the pouch mucosa.

Pouch and pouchitis

Pouchitis is an inflammation of unknown origin occurring in the ileal pouch after IPAA. It is considered by many to be a form of ulcerative colitis that recurs in the pouch and rarely, if ever, occurs in patients with FAP. Most patients respond to a short course of antibiotics. When remission cannot be maintained or the disease is nonresponsive to prolonged treatment with antibiotics, anti-inflammatory agents or steroids may be useful. A variety of alternative drugs have been tried with mixed success and should be considered as experimental. Rarely, when pouchitis is refractory to medical management, excision of the pouch may be required.

Oral bacteriotherapy as maintenance treatment in patients with chronic pouchitis: a double-blind, placebo-controlled trial

BACKGROUND & AIMS

Pouchitis is the major long-term complication after ileal pouch-anal anastomosis for ulcerative colitis. Most patients have relapsing disease, and no maintenance treatment study has been performed. We evaluated the efficacy of a probiotic preparation (VSL#3) containing 5 x 10(11) per gram of viable lyophilized bacteria of 4 strains of lactobacilli, 3 strains of bifidobacteria, and 1 strain of Streptococcus salivarius subsp. thermophilus compared with placebo in maintenance of remission of chronic pouchitis.

METHODS

Forty patients in clinical and endoscopic remission were randomized to receive either VSL#3, 6 g/day, or an identical placebo for 9 months. Patients were assessed clinically every month and endoscopically and histologically every 2 months or in the case of a relapse. Fecal samples were collected for stool culture before and after antibiotic treatment and each month during maintenance treatment.

RESULTS

Three patients (15%) in the VSL#3 group had relapses within the 9-month follow-up period, compared with 20 (100%) in the placebo group (P < 0.001). Fecal concentration of lactobacilli, bifidobacteria, and S. thermophilus increased significantly from baseline levels only in the VSL#3-treated group (P < 0.01).

CONCLUSIONS

These results suggest that oral administration of this new probiotic preparation is effective in preventing flare-ups of chronic pouchitis.

The role of probiotic cultures in the control of gastrointestinal health

The use of probiotics to enhance intestinal health has been proposed for many years. Probiotics are traditionally defined as viable microorganisms that have a beneficial effect in the prevention and treatment of specific pathologic conditions when they are ingested. There is a relatively large volume of literature that supports the use of probiotics to prevent or treat intestinal disorders. However, the scientific basis of probiotic use has been firmly established only recently, and sound clinical studies have begun to be published. Currently, the best-studied probiotics are the lactic acid bacteria, particularly Lactobacillus sp. and Bifidobacterium sp. However, other organisms used as probiotics in humans include Escherichia coli, Streptococcus sp., Enterococcus sp., Bacteroides sp., Bacillus sp., Propionibacterium sp. and various fungi. Some probiotic preparations contain mixtures of more than one bacterial strain. Probiotics have been examined for their effectiveness in the prevention and treatment of a diverse spectrum of gastrointestinal disorders such as antibiotic-associated diarrhea (including Clostridium difficile-associated intestinal disease), infectious bacterial and viral diarrhea (including diarrhea caused by rotavirus, Shigella, Salmonella, enterotoxigenic E. coli, Vibrio cholerae and human immunodeficiency virus/acquired immunodeficiency disorder, enteral feeding diarrhea, Helicobacter pylori gastroenteritis, sucrase maltase deficiency, inflammatory bowel disease, irritable bowel syndrome, small bowel bacterial overgrowth and lactose intolerance. Probiotics have been found to inhibit intestinal bacterial enzymes involved in the synthesis of colonic carcinogens. There are many mechanisms by which probiotics enhance intestinal health, including stimulation of immunity, competition for limited nutrients, inhibition of epithelial and mucosal adherence, inhibition of epithelial invasion and production of antimicrobial substances. Probiotics represent an exciting prophylactic and therapeutic advance, although additional investigations must be undertaken before their role in intestinal health can be delineated clearly.

A rat model of ileal pouch-rectal anastomosis

After colectomy and ileal pouch-rectal anastomosis, pouchitis may occur. Pouchitis is a poorly defined condition with unknown etiology. The aim of this study was to develop an animal model of pouchitis. Ileal pouch-rectal anastomosis was created in Lewis and Sprague-Dawley rats. Rats were studied 4 and 8 weeks after surgery, and pouchitis was assessed by stool output, histology, and tissue myeloperoxidase (MPO) levels. Some rats were treated with allopurinol or metronidazole beginning the day of surgery. Rats with pouches demonstrated inflammation with a monocytic infiltration, luminal exudate, mucosal ulcerations, and serosal inflammation. Rats with pouches had increased anaerobic bacterial flora compared with normal ileum. After creation of pouches, Lewis rats (histology score = 8.4 +/- 1.6; MPO = 17.3 +/- 3.6, mean +/- SD) developed more severe inflammation than Sprague-Dawley rats did (histology score = 4.3 +/- 1.8; MPO = 5.5 +/- 3.6) within 4 weeks, p < 0.001 and 8 weeks after surgery, p < 0.05. Stool output was also greater in Lewis (55 +/- 7 g/kg/day) compared with Sprague-Dawley rats with pouches (43 +/- 5 g/kg/day), p < 0.05. Metronidazole treatment reduced histology score (6.0 +/- 0.5) p < 0.05 and MPO (5.9 +/- 1.6) p < 0.001 in rats with pouches compared with rats with pouches that had no treatment. Allopurinol treatment in rats with pouches reduced histology score (4.0 +/- 1.7) and MPO (3.9 +/- 1.6), p < 0.001, compared with rats with pouches that had no treatment. Ileal pouch-rectal anastomosis in rats induced inflammation within 4 weeks, demonstrated differential host genetic susceptibility, and was associated with increased number of pouch bacteria. Anaerobes, especially bacteroides sp. and free radical, may mediate inflammation. Ileal pouch-rectal anastomosis surgery in rats may be a useful animal model for the study pouchitis.

Plasma and mucosal fatty acid pattern in colectomized ulcerative colitis patients

Patients with inflammatory bowel disease (IBD) have increased plasma n3 polyunsaturated fatty acids (PUFAs), which in ulcerative colitis (UC) patients persists six months after colectomy, suggesting a primary abnormality in fatty acid (FA) metabolism in IBD. This finding needed to be confirmed in a larger series of UC long-term colectomized patients. We aimed to assess the plasma FA pattern in UC colectomized patients with either Brooke's ileostomy (UC-BI) or ileal pouch anal anastomosis (UC-IPAA) and the mucosal FA pattern in the ileal reservoir of the UC-IPAA patients. Plasma FAs were assessed in 63 UC colectomized patients (31 with BI and 32 with IPAA) and 30 controls. In 26 UC-IPAA (8 with pouchitis and 18 without pouchitis) and in 13 healthy controls gut mucosal FAs were also investigated. FAs were detected by capillary column gas-liquid chromatography. Increased levels of saturated fatty acids (SFAs) and decreased percentages of monounsaturated fatty acids (MUFAs) were observed in both groups of patients. There were no changes in plasma n3 and n6 PUFAs. The mucosal FA pattern of the ileal reservoir consisted of increased long-chain PUFAs, specially n6 PUFA, and a decrease of their essential precursors. High percentages of SFAs and low percentages of MUFAs were also seen. The plasma FA profile previously described in IBD is not observed long-term after colectomy in UC, suggesting that it is related with the presence of inflamed intestine. High concentrations of SFAs and decreased percentages of MUFAs might represent early events in disturbed FA metabolism in IBD. The changes in FAs of the ileal reservoir, which closely resemble those found in human and experimental IBD, probably represent a common pattern of intestinal inflammation.

Preoperative terminal ileal and colonic resection histopathology predicts risk of pouchitis in patients after ileoanal pull-through procedure

OBJECTIVE

This study seeks to compare the histopathology of preoperative terminal ileal and colonic resection specimens with pouch biopsies after the ileoanal pull-through (IAPT) procedure.

SUMMARY BACKGROUND DATA

Pouchitis is the most frequent complication of transanal continent reservoirs in patients after IAPT.

METHODS

The authors conducted 751 consecutive pouch biopsies on 73 patients with inflammatory bowel disease or familial adenomatous polyposis who underwent IAPT by a single surgeon over a 10-year period. In this preliminary report, a pathologist, in blinded fashion, has graded 468 of the IAPT pouch biopsies and 67 of the patients' preoperative terminal ileal and colonic resection histopathology to date. Colonic histopathology was graded by the extent and severity of disease, terminal ileal and pouch histopathology by active inflammation, chronic inflammation, lymphocyte aggregates, intraepithelial lymphocytes, eosinophils, and villous blunting.

RESULTS

Extent of colonic disease (gross and microscopic) was a significant predictor of active inflammation in subsequent IAPT pouch biopsy specimens. Also, the gross extent of colonic disease exhibited a significant linear association with pouch inflammation. However, the severity of colonic disease was not significantly predictive of active inflammation in subsequent IAPT pouch biopsies. Terminal ileal active and chronic inflammation were significant predictors of subsequent IAPT pouch inflammation. Although lymphocyte aggregates and intraepithelial lymphocytes were not predictive, terminal ileum eosinophils and villous blunting were significant predictors of active inflammation in subsequent IAPT pouch biopsy specimens.

CONCLUSIONS

Preoperative terminal ileal and colonic histopathology predicts active inflammation of pouches after IAPT. Patients who are preoperatively assessed to have extensive disease of the colon, ileal disease ("backwash ileitis"), or both appear to be at greater risk for the development of pouchitis after IAPT.

Pouchitis

Pouchitis is a major long-term complication of the continent ileostomy as well as the ileoanal pouch anastomosis. When diagnosed on the basis of clinical, endoscopic and histologic features, this syndrome has been demonstrated almost exclusively in patients with ulcerative colitis. The clinical course, the endoscopic findings and the histologic abnormalities resemble those of ulcerative colitis. The association with extra-intestinal manifestations further supports the hypothesis that pouchitis represents ulcerative colitis in the small bowel. All ileal reservoirs show bacterial overgrowth, especially of anaerobes. As a response to this altered intraluminal environment chronic inflammation and incomplete colonic metaplasia occur. The efficiency of metronidazole does suggest that bacteriological factors play an important role in the pathogenesis of pouchitis.

Crohn's-like complications in patients with ulcerative colitis after total proctocolectomy and ileal pouch-anal anastomosis

Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) has become an established surgical procedure for ulcerative colitis. Occasional patients who have undergone IPAA develop persistent or recurrent episodes of pouchitis (chronic pouchitis), from which a subset also develop gastrointestinal and systemic complications that are identical to those seen in Crohn's disease. These complications include enteric stenoses or fistulas in the pouch or pouch inlet segment, perianal fistulas or abscesses, pouch fistulas, arthritis, iridocyclitis, and pyoderma gangrenosum. The development of Crohn's-like gastrointestinal complications in a patient with chronic pouchitis frequently engenders concern that the pathologist misinterpreted the proctocolectomy specimen as ulcerative colitis instead of Crohn's disease. We describe eight patients who developed chronic pouchitis and Crohn's-like complications after IPAA and total proctocolectomy. In each case, concern was voiced about misinterpretation of the proctocolectomy specimen as ulcerative colitis instead of Crohn's disease after the development of the Crohn's-like complications. Preoperatively, all eight patients had characteristic clinical, radiographic, and pathologic features of ulcerative colitis. Review of the pathology specimens indicated that all eight had ulcerative colitis. Crohn's-like complications are most likely related to chronic pouchitis, which probably is a form of recrudescent ulcerative colitis within the novel environment of the pouch. A diagnosis of Crohn's disease after IPAA surgery should only be made when reexamination of the original proctocolectomy specimen shows typical pathologic features of Crohn's disease, Crohn's disease arises in parts of the gastrointestinal tract distant from the pouch, pouch biopsies contain active enteritis with granulomas, or excised pouches show the characteristic features of Crohn's disease, including granulomas. There were no histologic differences in the total colectomy specimens between the eight ulcerative colitis study patients and 16 control ulcerative colitis patients who had a favorable clinical outcome after IPAA surgery groups. Crohn's-like complications and chronic pouchitis does not necessarily imply an incorrect original interpretation of ulcerative colitis by the pathologist.