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

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

Lactobacillus acidophilus alleviates pouchitis after ileal pouch-anal anastomosis in rats

AIM

To assess the therapeutic potential of Lactobacillus acidophilus (LA) for the treatment of pouchitis in a rat model.

METHODS

Sprague Dawley rats underwent proctocolectomy and ileal pouch-anal anastomosis followed by administration of dextran sulfate sodium (DSS) to induce pouchitis. Rats with pouchitis were randomly divided into three groups: no intervention (NI), normal saline (NS, 3 mL/d normal saline for 7 d), and LA (3 mL/d LA at 1× 10¹⁰ colony-forming units for 7 d). General body condition was recorded and pouch specimens were obtained for histological examination. mRNA expression levels of interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor-α were determined by RT-PCR. Zonula occludens protein 1 (ZO-1) levels were measured by immunohistochemistry.

RESULTS

LA reduced weight loss associated with pouchitis (P < 0.05) and improved the symptoms of pouchitis in rats. Compared with the NI and NS groups, rats in the LA group showed earlier disappearance of hematochezia (6.17 ± 0.75, 6.50 ± 0.55, 3.17 ± 0.75, P < 0.05) and higher fecal scores (2.67 ± 0.48, 2.50 ± 0.51, 4.42 ± 0.50, respectively, P < 0.05). Histological scores were also lower in the LA group compared with the other two groups (7.17 ± 0.98, 8.00 ± 0.89, 4.00 ± 0.89, respectively, P < 0.05). mRNA expression levels of IL-1β, IL-6, and tumor necrosis factor-α were significantly reduced, while IL-10 mRNA levels were significantly increased in the LA group (P < 0.05, respectively). ZO-1 protein levels were also significantly increased after administration of LA (P < 0.05).

CONCLUSION

LA alleviates pouchitis induced by DSS after ileal pouch-anal anastomosis by decreasing pro-inflammatory factors and increasing anti-inflammatory factors, and restoring ZO-1 expression in the mucosa.

Roles for Intestinal Bacteria, Viruses, and Fungi in Pathogenesis of Inflammatory Bowel Diseases and Therapeutic Approaches

Intestinal microbiota are involved in the pathogenesis of Crohn's disease, ulcerative colitis, and pouchitis. We review the mechanisms by which these gut bacteria, fungi, and viruses mediate mucosal homeostasis via their composite genes (metagenome) and metabolic products (metabolome). We explain how alterations to their profiles and functions under conditions of dysbiosis contribute to inflammation and effector immune responses that mediate inflammatory bowel diseases (IBD) in humans and enterocolitis in mice. It could be possible to engineer the intestinal environment by modifying the microbiota community structure or function to treat patients with IBD-either with individual agents, via dietary management, or as adjuncts to immunosuppressive drugs. We summarize the latest information on therapeutic use of fecal microbial transplantation and propose improved strategies to selectively normalize the dysbiotic microbiome in personalized approaches to treatment.

Tight junctions in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer

Inflammatory bowel diseases are characterised by inflammation that compromises the integrity of the epithelial barrier. The intestinal epithelium is not only a static barrier but has evolved complex mechanisms to control and regulate bacterial interactions with the mucosal surface. Apical tight junction proteins are critical in the maintenance of epithelial barrier function and control of paracellular permeability. The characterisation of alterations in tight junction proteins as key players in epithelial barrier function in inflammatory bowel diseases is rapidly enhancing our understanding of critical mechanisms in disease pathogenesis as well as novel therapeutic opportunities. Here we give an overview of recent literature focusing on the role of tight junction proteins, in particular claudins, in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer.

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.

Ki-67 and p53 expression in ileal pouches

Development of dysplastic lesions that may potentially lead to cancer is sometimes reported within the ileal pouches. Dysplasia is in turn associated with increased expression of proliferation indices. The goal of this study was to evaluate the mitotic activity and possible expression of p53 in the epithelium within the ileal pouches in patients with chronic ulcerative colitis. The study involved archive material consisting of ileal pouches surgically removed from 17 patients diagnosed with ulcerative colitis. Several specimens were collected from each pouch. The immunohistochemistry (Ki-67 and p53 protein) control group (14 cases) consisted of the resection line specimens of colons removed due to colorectal adenocarcinoma. Intensity of the expression of the markers under study within the inflammatory infiltrates was assessed using a 5-point scale proposed by Berstein et al. Ki-67 expression was observed in all studied patients with marked intensity (Bernstein scale score +3, +4). Protein p53 expression was observed only in eight patients, and was mostly of low intensity (Bernstein scale score +1, +2). Immunohistochemical results confirmed the histopathological results that revealed dysplastic lesions, which are often an indication for radical procedures in ulcerative colitis patients. Our results suggest the usefulness of these examinations, also in the ileal pouch material.

Inulin supplementation in rat model of pouchitis

Available data indicates potential effectiveness of prebiotic therapy in alleviating inflammation and prolonging the remission in inflammatory bowel disease. Documented successes of such therapies were the basis for this study. So far, there is no data related to the effectiveness of inulin application in symptomatic or severe pouchitis in humans or in animal model. The aim of the study was to determine the effect of inulin supplementation on the expression of intestinal inflammation and feeding efficiency in rats with induced pouchitis. Twenty-four Wistar rats were operated. After induction of pouchitis animals were randomly divided into control and supplementation groups receiving, respectively, semi-synthetic diet with or without inulin (in a lower (LD) or higher (HD) dose: 2.5 % or 5 % of total dietary content of mass) for a period of 6 weeks. Selected nutritional parameters were assessed throughout the study. Histopathological and immunohistochemical analysis of pouch mucosa specimens was also performed. The energy intake, weight gain, feeding efficiency, quality of stools were comparable in all studied groups. The intensity of inflammation (Moskovitz scale) and adaptive changes (Laumonier scale) did not differ between compared groups. The tissue expression of pro- and anti-inflammatory interleukins (IL-1α, IL-6, IL-10 and IL-12) was not different either. Inulin supplementation does not improve the quality of stools or the expression of intestinal inflammation in rats with induced pouchitis. It has no impact on the intensity of pouch adaptation or on feeding efficiency.

Activation of signal transducer and activator of transcription-1 (STAT-1) and differential expression of interferon-gamma and anti-inflammatory proteins in pelvic ileal pouches for ulcerative colitis and familial adenomatous polyposis

Pouchitis after total rectocolectomy is the most common complication of ulcerative colitis (UC). The immunological mechanisms involved in the genesis of pouchitis are unclear. Therefore, we evaluated the inflammatory activity in normal ileal pouch mucosa by determining signal transducers and activators of transcription (STAT-1) activation and cytokine expression in patients operated for UC and familial adenomatous polyposis (FAP). Eighteen asymptomatic patients, who underwent total rectocolectomy and J pouch, were evaluated: nine with UC and nine with FAP. The activation of STAT-1 and cytokine expression were determined by immunoblot of total protein extracts from pouch mucosal biopsies. The absence of pouchitis was assessed by clinical, histological and endoscopic parameters, according to the Pouchitis Disease Activity Index. The patients were not receiving any medication. Analysis of variance (anova) and Tukey-Kramer's test were applied. The local ethical committee approved the study and informed consent was signed by all participants. STAT-1 activation was increased in UC when compared to FAP and controls (P < 0.05). Higher levels of interferon (IFN)-gamma expression were observed in UC patients when compared to the control group (P < 0.05), but were similar to FAP. In contrast, cytokine signalling (SOCS-3) and interleukin (IL)-10 expression were similar in all groups (P > 0.05). These findings could explain the higher susceptibility to this inflammatory complication in UC when compared to FAP. A tendency towards increased levels of IFN-gamma and STAT-1 in patients with UC, even without clinical and endoscopic evidence of pouchitis, was observed; studying inflammatory activity in asymptomatic ileal pouches may help understanding of the pathogenesis of pouchitis.

Inflamed pouch mucosa possesses altered tight junctions indicating recurrence of inflammatory bowel disease

BACKGROUND AND AIMS

The etiology of pouchitis after coloproctomucosectomy with ileal pouch-anal anastomosis in patients with ulcerative colitis is still unknown. Beside changes in luminal antigens, the immunological predisposition is assumed to be responsible. In previous electrophysiological studies, we showed that mucosal barrier and transport function in pouchitis is markedly reduced. Thus, the aim of the present study was to analyze barrier function on the molecular level.

MATERIAL AND METHODS

Pouch biopsies of 36 ulcerative colitis patients were analyzed. Time points were (1) intraoperative immediately prior to ileal pouch-anal anastomosis (n = 13), (2) >1 year after ileostomy closure (pouch, n = 12), and (3) during pouchitis (n = 11). Control terminal ileum biopsies were obtained from eight patients undergoing hemicolectomy due to carcinoma. Expression of tight junction proteins was analyzed by Western blotting and confocal laser-scanning microscopy. To elucidate effects on epithelial barrier properties, impedance spectroscopy was performed in miniaturized Ussing chambers.

RESULTS

In pouchitis, epithelial resistance was markedly reduced compared to non-inflamed pouch and control ileum. Expression of tight junction proteins claudin-1, 3, 4, 5, and 7 and occludin revealed differential expression regulation with the tightening tight junction protein claudin-1 being decreased and an increase of the pore-forming claudin-2, whereas other claudins remained constant. Morphometry indicated the mucosal surface to be unchanged.

CONCLUSION

Pouchitis is characterized by a selective change of tight junction proteins in favor of opening the epithelial tight junction and, thus, the paracellular pathway, which contributes to the inflammatory process. This resembles changes in inflammatory bowel disease (IBD) and indicates IBD recurrence in pouchitis.

Increased bacterial permeation in long-lasting ileoanal pouches

BACKGROUND AND AIMS

Bacterial overgrowth appears to play an important role in the pathogenesis of ileoanal pouches. Therefore, the capability of bacterial permeation and its determinants is of great interest. The aim of this study was to examine bacterial permeation in the ileoanal pouch and to correlate the results with the degree of inflammation, the epithelial resistance, the mucosal transport function, and the age of the ileoanal pouches.

MATERIALS AND METHODS

Biopsies were taken from 54 patients before colectomy (n = 13; preileal pouch-anal anastomosis [IPAA]), and closure of ileostomy (n = 7; deviation), <1 year after closure of ileostomy (n = 8; intact pouch I), >1 year after closure of ileostomy (n = 16; intact pouch II), in the case of pouchitis (n = 11), and in 11 controls. Tissues were mounted in a miniaturized Ussing chamber. Escherichia coli was added to the mucosal side of the Ussing chamber, and the permeation was proven by serosal presence of E. coli. Epithelial and subepithelial resistance was determined by transmural impedance analysis. Active Na-glucose cotransport and active Cl secretion were measured. Specimens were analyzed by fluorescent in situ hybridization with oligonucleotide probes targeting the bacterial 16s ribosomal RNA. The bacteria in and on the tissue were enumerated.

RESULTS

Bacterial permeation occurred in 2 of 13 pre-IPAA, 2 of 7 deviations, 0 of 8 intact pouch I, 9 of 16 intact pouch II, 5 of 11 pouchitis specimens, and 0 of 11 ileum controls. The frequency of bacterial permeation in the intact pouch II group is higher than in the intact pouch I group (P < 0.001). Epithelial resistance, mannitol fluxes, electrogenic chloride secretion, sodium-glucose cotransport of the bacterially permeated specimens versus nonpermeated of the intact pouch II group, and the pouchitis group and subepithelial resistance remained unchanged. Intramural bacteria could be detected by fluorescence in situ hybridization mainly in long-lasting pouches, but there was no correlation with bacterial permeation.

CONCLUSIONS

The long-lasting ileoanal pouch is associated with increased bacterial permeability. This is not correlated with a disturbed function of the pouch mucosa but could be a precursor of pouchitis.

The expression patterns of Toll-like receptors in the ileal pouch mucosa of postoperative ulcerative colitis patients

The aim of this study was to evaluate the expression pattern of Toll-like receptors (TLRs) in the pouch mucosa of ulcerative colitis patients in comparison with that in the ileum mucosa of noninflammatory bowel disease patients. Pouch mucosal biopsy specimens were collected from postoperative patients who had undergone surgery for ulcerative colitis. Normal ileum specimens were collected from colon cancer patients. The specimens were assessed by immunofluorescence histochemistry using TLR2, TLR3, TLR4, and TLR5 polyclonal antibodies. The normal ileal mucosa constitutively expressed TLR3 and TLR5, whereas TLR2 and TLR4 were barely detectable. In the mucosa of active pouchitis, TLR2 and TLR4 was strongly upregulated, and TLR4 was upregulated even in a noninflamed pouch. No TLR3 or TLR5 expression was detectable. These data suggest that pouchitis may be associated with distinctive changes in selective TLR expression in the pouch mucosa, and that TLR4 alterations in the innate response system may contribute to the pathogenesis of these disorders in particular.

Increased cytokine transcripts in pouchitis reflect the degree of inflammation but not the underlying entity

BACKGROUND AND AIMS

After ileopouch anal anastomosis (IPAA), 10-40% of patients with ulcerative colitis (UC) but only 5% of patients with familial adenomatous polyposis (FAP) develop pouchitis. Immunoregulatory abnormalities might be of importance in the pathogenesis of the disease. Therefore, we characterized cytokine and chemokine transcripts in inflamed and non-inflamed pouches in patients with UC compared to those with FAP and Crohn's disease (CD).

PATIENTS AND METHODS

Mucosal biopsies were taken from 87 patients with IPAA [UC (n=70), CD (n=8) or FAP (n=9)]. Patients with active ileal CD (n=14), active UC (n=17) and non-inflammatory conditions (n=12) served as controls. The expression of 20 gene transcripts was quantified using real-time polymerase chain reaction.

RESULTS AND FINDINGS

Pro-inflammatory cytokines and chemokines are significantly increased in IPAA patients with acute pouchitis. This increase is independent of the underlying disease (UC or CD) and reflects the degree of inflammation. A good correlation between pouchitis activity (using the Pouchitis Disease Activity Index) and the MRP-14, interleukin-8, macrophage inflammatory protein-2alpha and matrix metalloproteinase-1 transcripts was observed.

INTERPRETATIONS AND CONCLUSIONS

Our data support the view that pouchitis reflects an inflammatory process that is different from that of underlying inflammatory bowel diseases, as the cytokine and chemokine patterns in pouchitis are neither typical of CD nor of UC, but maybe due to bacterial intestinal microflora overgrowth in the pouch lumen. Quantification of transcript levels allows an estimation of the extent of mucosal inflammation and may become helpful in the evaluation of the disease, especially in clinical trials.

Pre-pouch ileitis: a disease of the ileum in ulcerative colitis after restorative proctocolectomy

OBJECTIVE

Ileal inflammation in ulcerative colitis can occur as backwash ileitis or prestomal ileitis. After restorative proctocolectomy (RPC), ileal inflammation may be present in the pouch (pouchitis) but inflammation proximal to the pouch in the neo-terminal ileum, so called pre-pouch ileitis (PI), has also been observed. As pouchitis is increasingly common and PI can mimic it, our aim was to characterize this condition.

SUBJECTS AND METHODS

A review of prospectively collected data on 571 inflammatory bowel disease patients undergoing follow-up after RPC in a single centre over 22 years was performed. The histology of biopsy material was reviewed and staining for colonic mucosal phenotypic changes was undertaken. It was not routine practice to prospectively assess all patients for pre-pouch ileitis when the database was constructed.

RESULTS

Of 19 patients with inflammation of the pre-pouch neo-terminal ileum (NTI) identified three had Crohn's disease and one a NSAID stricture. The remaining 15 had a characteristic diffuse inflammation extending from the NTI-pouch junction proximally: pre-pouch ileitis. The inflammation extended proximally for up to 50 cm. Fistula formation was seen in only one. Seven (47%) of 15 had pouchitis but only two had suffered backwash ileitis pre-operatively. Seven responded to medical therapy and four to surgery. The histological appearances including staining for colonic phenotypic change were similar in PI and pouchitis.

CONCLUSION

Pre-pouch ileitis is uncommon. As the patients' previous diagnosis of UC was confirmed and there was no radiological or histological evidence of Crohn's disease, PI appears to have a distinct pathogenesis from Crohn's disease.

Relationships between mucinous gastric carcinoma, MUC2 expression and survival

AIM: Pouchitis develops in ileoanal pouches in up to 50% of patients with ulcerative colitis during the first 10 years after pouch surgery while being rare in patients after proctocolectomy for familial adenomatous polyposis coli (FAP) syndrome. Defensins are major components of the innate immune system and play a significant role in gastrointestinal microbial homeostasis. Pouch defensin and cytokine expression were correlated with states of pouch inflammation to study their role in pouchitis.

METHODS: Patients with ulcerative colitis and FAP syndrome were stratified into groups with pouches after surgery, pouches without or with pouchitis. Biopsies from terminal ileum from a healthy intestine or from normal terminal ileum of patients with ulcerative colitis served as controls. mRNA from pouches and controls was analysed for defensin and cytokine expression.

RESULTS: Expression of defensins was increased in all pouches immediately after surgery, compared to ileum of controls. Initially, pouches in ulcerative colitis revealed higher defensin expression than FAP pouches. Defensin expression declined in both patient groups and increased again slightly in pouchitis in patients with ulcerative colitis. FAP pouches without pouchitis had strong expression of β-defensin hBD-1, while all other defensins remained at low levels. Cytokine expression in ulcerative colitis pouches was high, while FAP pouches showed moderately elevated cytokines only after surgery.

CONCLUSION: Development of pouchitis correlates with decreased defensin expression in ulcerative colitis in addition to high expression of cytokines. The low incidence of pouchitis in FAP pouches correlates with increased expression of hBD-1 β- defensin in association with low cytokine levels.

Persistence of high CD40 and CD40L expression after restorative proctocolectomy for ulcerative colitis

AIM: To focus on the role of CD40 and CD40L in their pathogenesis.

METHODS: We analyzed by immunohistochemistry the CD40 and CD40L expression in the pouch mucosa of 28 patients who had undergone RPC for UC, in the terminal ileum of 6 patients with UC and 11 healthy subjects. We also examined by flow cytometry the expression of CD40 by B lymphocytes and monocytes in the peripheral blood of 20 pouch patients, 15 UC patients and 11 healthy controls.

RESULTS: Ileal pouch mucosa leukocytes presented a significantly higher expression of CD40 and CD40L as compared to controls. This alteration correlated with pouchitis, but was also present in the healthy pouch and in the terminal ileum of UC patients. CD40 expression of peripheral B lymphocytes was significantly higher in patients with UC and pouch, respect to controls. Increased CD40 levels in blood B cells of pouch patients correlated with the presence of spondyloarthropathy, but not with pouchitis, or inflammatory indices.

CONCLUSION: High CD40 expression in the ileal pouch mucosa could be implied in the pathogenesis of pouchitis following proctocolectomy for UC, whereas its increased levels on peripheral blood B lymphocytes are associated with the presence of extraintestinal manifestations.

Expression of keratinocyte growth factor and its receptor in adaptive changes of ileorectal pouch mucosa

OBJECTIVE

Total proctocolectomy with formation of an ileo-anal pouch is a well-established surgical procedure for patients with ulcerative colitis (UC) or familiar adenomatous polyposis (FAP). The pouch mucosa undergoes adaptive changes, with inflammation of the ileal reservoir being the most common complication. The aetiology is unknown. The keratinocyte growth factor (KGF) has not only been shown to promote intestinal wound healing and re-epithelialization but also to have some immunomodulatory properties. This study was designed to investigate a putative involvement of KGF in observed histomorphological changes in the pouch mucosa.

MATERIALS AND METHODS

Multiple biopsies were obtained from age-matched and sex-matched patients. Biopsies were stained with H&E and scored for inflammation and morphological changes. mRNA expression levels of KGF and KGF-receptor (KGFR) were determined using competitive RT-PCR, protein expression and phosphorylation was analyzed by Western blotting. KGF and KGFR were localized in tissue samples by immunohistochemistry.

RESULTS

Expression of KGF and KGFR was significantly increased in inflamed and adapting mucosa. Patterns of expression did not significantly differ in pouch mucosa from UC or FAP patients. Protein expression correlated with the mRNA results and KGFR was shown to be activated in adapting pouch mucosa. KGF was detected on subepithelial cells, mainly on fibroblasts, whereas expression of KGFR was restricted to epithelial cells.

CONCLUSION

Expression of KGF and KGFR is significantly increased in the pouch mucosa, suggesting an involvement of this growth factor in tissue repair and adaptive changes. Topical application of KGF might alleviate the inflammatory and promote the adaptive process in the ileo-anal pouch mucosa.

Probiotic therapy in the prevention of pouchitis onset: decreased interleukin-1beta, interleukin-8, and interferon-gamma gene expression

BACKGROUND

Probiotic therapy has been shown to prevent the onset of pouchitis and to improve the quality of life in ulcerative colitis patients who required ileal pouch anal anastomosis. Pouchitis has been associated with elevated levels of proinflammatory cytokines and chemokines.

METHODS

In this retrospective analysis of archived endoscopic samples from responding patients enrolled in the above-mentioned trial, we were interested in studying mucosal gene expression of the pleiotropic proinflammatory cytokines (interleukin-1beta, interleukin-6), TH1 cytokines (interferon-gamma, tumor necrosis factor-alpha, interleukin-12), regulatory cytokines (interleukin-10, transforming growth factor-beta), and the chemokine interleukin-8. In addition to assessment of cytokine gene expression, the presence of polymorphonuclear cells in the mucosal tissue was evaluated.

RESULTS

Data show that patients who were treated with probiotics had significant lower mucosal mRNA expression levels of interleukin-1beta, interleukin-8, and interferon-gamma compared with placebo-treated patients. In addition, a lower number of polymorphonuclear cells was present in the tissue of patients within the probiotic group compared with the number of polymorphonuclear cells in the tissue of patients receiving placebo and patients having an episode of pouchitis.

CONCLUSIONS

These data suggest that probiotic treatment regulates the mucosal immune response by reducing mucosal levels of neutrophil-chemoattractant IL-8 and tissue influx of polymorphonuclear cells, and may further act by inhibition of T-cell activation, by reinforcement of barrier function and by a tight control of the potent pro-inflammatory cytokine IL-1beta.

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.

Impairment of epithelial transport but not of barrier function in idiopathic pouchitis after ulcerative colitis

BACKGROUND AND AIMS

Little is known of the permeability of ileoanal pouches. Hence the aim of the present study was to determine changes in permeability and mucosal function after ileo-pouchanal anastomosis (IPAA) in patients with ulcerative colitis.

MATERIALS AND METHODS

Biopsies were taken from 43 patients (male:female ratio 28:15; mean age 35.2 (12.5) years) prior to colectomy (ileum prior to pouch), prior to closure of ileostomy (deviation), and after closure of ileostomy (intact pouch) in the case of pouchitis, and from 14 healthy controls. Tissues were mounted in a miniaturised Ussing chamber. Epithelial and subepithelial resistance was determined by transmural impedance analysis. Active Na(+)-glucose cotransport was measured as change in short circuit current after stepwise addition of glucose, and active Cl(-) secretion was measured after stimulation with theophylline and prostaglandin E(2).

RESULTS

Neither epithelial resistance nor mannitol fluxes were significantly altered compared with intact controls, indicating no barrier defect in pouchitis. Subepithelial resistances of intact pouches and pouchitis were increased compared with deviation (18.2 (1.6) and 24.3 (1.5) v. 13.6 (1.0) Omegaxcm(2)) consistent with an adaptive thickening of the subepithelial layer. In contrast, active Cl(-) secretion of pouchitis tissues was reduced versus intact pouch and controls (1.4 (0.3) v. 4.3 (0.7) and 4.6 (0.7) micromol/h/cm(2)), and Na(+)-glucose cotransport of pouchitis was reduced compared with intact pouch and controls (1.8 (0.5) v. 4.2 (0.8) and 8.8 (1.3) micromol/h/cm(2)).

CONCLUSIONS

Ileal mucosa in pouchitis and terminal ileum prior to IPAA exhibit impaired secretory and absorptive transport functions whereas the epithelial barrier function remains unchanged. This differs from findings in ulcerative colitis. Thus the hypothesis that pouchitis represents a remanifestation of ulcerative colitis has to be questioned.

Long term metabolic consequences of ileal pouch-anal anastomosis for ulcerative colitis

OBJECTIVES

Chronic inflammation in the ileal pouch is the most significant late complication after ileal pouch-anal anastomosis (IPAA). It leads to changes in mucosal morphology, with consequent decreased vitamin B12, bile acid and cholesterol absorption documented. The aims of this study were to evaluate long term metabolic consequences at least 5 yr after IPAA and the influence of pouchitis on pouch histology and on bile acid, lipid, and vitamin B12, A, E, and D metabolism.

METHODS

A total of 104 patients with a J-pouch who were operated on between 1985 and 1994, as well as 21 ulcerative colitis patients with a conventional ileostomy were enrolled for the study. Routine blood tests, vitamin status, vitamin B12 levels, and bile acid absorption were determined, as well as endoscopy with biopsies. The pouchitis disease activity index (PDAI) was calculated. On the basis of histology, IPAA patients were divided into three subgroups: 1) those with no villous atrophy, 2) those with partial villous atrophy, and 3) those with subtotal or total villous atrophy.

RESULTS

Incidence of pouchitis was 42.3%, and was strongly associated with villous atrophy. In IPAA patients with subtotal or total villous atrophy (32.7%), serum levels of albumin, calcium, total cholesterol, triglycerides, and vitamin E were significantly reduced (p < 0.05). The lowest bile acid and vitamin B12 absorption rates were seen in patients with inflammation in the proximal limb. Vitamin D deficiency was seen in 10.6%, and vitamin A and B12 deficiency in approximately 5% of IPAA patients.

CONCLUSIONS

Metabolic consequences after IPAA are associated with pouchitis, grade of villous atrophy, and extent of inflammation in the remaining ileum. Patients with active chronic inflammation need long term follow-up.

Ulcer associated cell lineage glands expressing trefoil peptide genes are induced by chronic ulceration in ileal pouch mucosa

BACKGROUND

Chronic ulcerative conditions in the gastrointestinal tract result in the appearance of the ulcer associated cell lineage (UACL). The glands of this new cell lineage secrete epidermal growth factor, transforming growth factor alpha, and the trefoil factor family (TFF) peptides, which are known to participate in repair processes. Pouchitis is the most frequent complication of ileal pouch-anal anastomosis.

AIM

Our aim was to determine whether the mucosal ulceration present in pouchitis can induce the development of UACL glands.

METHODS

Biopsies from ileal pouches with pouchitis (n=10), healthy pouches (n=5), and normal terminal ileum (n=5) were studied. Expression of TFF mRNA was assessed by in situ hybridisation. TFF1 and TFF2 proteins were localised by immunochemistry.

RESULTS

UACL glands containing TFF1 and TFF2 were observed in six patients with pouchitis. In some glands, there was TFF3 mRNA as has been reported for Crohn's UACL. None of the biopsies from ileal reservoirs without pouchitis showed UACL glands (p<0.05). Neither TFF1 nor TFF2 expression was detected in ileal reservoirs without pouchitis.

CONCLUSION

UACL glands arise de novo in ileal pouch mucosa of patients with pouchitis and express all three TFF peptide genes. Chronic inflammation alone, present in healthy pouches, is not enough to stimulate the growth of the UACL, and additional stimuli consequent on ulceration may be needed.

Simple gas chromatography analysis of faecal butyrate: application to patients at risk of pouchitis

In spite of the fact that pouchitis is the most frequently occurring and troublesome complication found in patients treated by ileo-anal anastomosis for ulcerative colitis, no biological marker currently exists to monitor the outcome of the disease. Since it has been noted faecal butyrate is reduced in patients with pouchitis, we developed a simple gas chromatography method to quantify butyrate in faecal water. This test is based on diethyl ether extraction with the use of methacrylic acid as an internal standard. We demonstrated that butyrate was effectively measured when this technique was applied to eleven patients with ileal-pouch anal anastomosis within the first year after the closure of their ileostomy. We also observed a noticeable reduction in the concentration of butyrate in patients who went on to develop a pouchitis.

Immunoglobulin G and albumin levels in whole gut lavage fluid provide an objective measure of pouch ileitis

BACKGROUND

Gut protein loss is a characteristic of inflammatory bowel disease (IBD), and immunoglobulin (Ig) G, albumin and alpha1-antitrypsin concentrations in whole gut lavage fluid (WGLF) correlate with clinical disease activity. If inflammation in ileoanal pouches is similar to IBD, then measurement of protein-losing enteropathy by analysis of WGLF may provide an objective assessment of disease activity in pouches.

METHODS

Forty-two patients who had restorative proctocolectomy for ulcerative colitis underwent whole gut lavage with a polyethylene glycol-electrolyte solution. The first clear effluent was filtered, processed by the addition of protease inhibitors and stored at - 70 degrees C. IgG, albumin and alpha1-antitrypsin were assayed in WGLF. The Pouchitis Disease Activity Index (PDAI) was calculated after pouchoscopy and biopsy; the Moskowitz criteria for pouchitis were also applied.

RESULTS

There was a significant correlation of the pouchoscopy score and the PDAI with the concentration of WGLF IgG. All patients with 'pouchitis' according to the Moskowitz criteria had a WGLF IgG concentration greater than 10 microg/ml. The WGLF albumin level also showed a significant correlation with the PDAI, but alpha1-antitrypsin concentration did not.

CONCLUSION

Analysis of WGLF for IgG and albumin may be useful in the assessment of disease activity in pouch inflammation.

Assessment of ileal pouch inflammation by single-stool calprotectin assay

PURPOSE

Assessment of inflammation within the ileal pouch to establish a diagnosis of "pouchitis" requires both pouch endoscopy and biopsy because there can be a poor correlation between macroscopic and histologic assessments of inflammation. A simplified diagnostic test would be of clinical advantage. Calprotectin is a stable myelomonocytic protein, measurable in feces. It quantitatively relates to inflammation within the gastrointestinal tract. This study was designed to compare single and 24-hour stool measurements of calprotectin in patients with and without evidence of ileal pouch inflammation with endoscopic, histologic, and immunohistochemical indices.

METHODS

Twenty-four-hour stool collections were made in ileal pouch patients, 9 with and 15 without (7 with ulcerative colitis and 8 with familial polyposis coli) evidence of pouch inflammation. First-morning stool concentration and total 24-hour calprotectin were quantified by use of a single step enzyme-linked immunosorbent assay. Biopsies from the reservoir were taken for conventional histology and scoring of intraepithelial neutrophil infiltrate. Cells positive for CD3, CD45RO, CD14, and CD15 within the lamina propria were quantified by use of immunohistochemistry.

RESULTS

The mean first-morning stool calprotectin concentration correlated with the 24-hour level (r = 0.91; P = <0.0001). The median single-stool calprotectin concentrations were 39 mg/l, 4 mg/l, and 8.5 mg/l (normal range, 0.2-10 mg/l) in patients with inflamed, noninflamed ulcerative colitis, and familial adenomatous polyposis, respectively. All nine patients with endoscopic and histologic evidence of pouch inflammation had raised stool calprotectin. Two of 15 patients without evidence of pouch inflammation had abnormal stool calprotectin. Single-stool calprotectin concentration correlated with the percentage of mature granulocytes (CD15; r = 0.46; P = 0.04) and activated macrophages (CD14; r = 0.65; P = 0.006), but not memory T cells (CD45RO; r = -0.05; P = 0.4) within the lamina propria.

CONCLUSION

Single first-morning stool calprotectin levels provide a quantitative measure of pouch inflammation, which may be helpful in the diagnosis and assessment of pouchitis.

Biliary lactoferrin concentrations are increased in active inflammatory bowel disease: a factor in the pathogenesis of primary sclerosing cholangitis?

1. One hypothesis for the link between inflammatory bowel disease and primary sclerosing cholangitis is that neutrophil activators, such as bacterial chemotactic peptides or neutrophil granule products themselves, pass from the inflamed colon to the liver via an enterohepatic circulation. However, there are no data on biliary concentrations of neutrophil granule products in patients with active and inactive inflammatory bowel disease.2. Gall bladder bile was obtained at laparotomy from 42 patients with ulcerative colitis and 21 patients with Crohn's disease. Biliary lactoferrin and myeloperoxidase concentrations were quantified by ELISA.3. In active ulcerative colitis, the mean lactoferrin concentration in gall bladder bile of 2.8+/-0.40 mg/l was higher than that seen after colectomy (1.2+/-0.11 mg/l; P<0.0001) or in patients with pouchitis (1.8+/-0.34 mg/l; P=0.06). In active Crohn's colitis, the mean lactoferrin concentration was 3.7+/-0.9 mg/l, compared with 1.1+/-0. 24 mg/l in the post-colectomy group (P<0.05) and 3.1+/-0.71 mg/l in those with active ileitis or ileocolitis. In contrast, biliary myeloperoxidase concentrations were low and comparable in all groups, with a mean concentration in the 42 patients with ulcerative colitis of 11.2+/-1.9 microgram/l.4. In contrast to myeloperoxidase, biliary lactoferrin concentrations are increased in active ulcerative colitis and Crohn's disease, and fall with colectomy and with disease remission. These findings indirectly support the hypothesis that bacterial chemotactic peptides (which induce selective degranulation of neutrophil secondary granules), and/or lactoferrin itself, undergo an enterohepatic circulation.

Increased state of activation of CD4 positive T cells and elevated interferon gamma production in pouchitis

BACKGROUND

Immunoregulatory abnormalities of T cells might be of importance in the pathogenesis of pouchitis after ileoanal pouch anastomosis (IAP).

AIMS

To characterise T cell subsets, their state of activation, and production of cytokines in inflamed and non-inflamed pouches in patients with ulcerative colitis (UC) and familial adenomatous polyposis (FAP). The influence of T cell activation on mucosal transformation was also studied.

PATIENTS

Mucosal biopsy specimens were taken from 42 patients with IAP (33 with UC and nine with FAP).

METHODS

Mononuclear cells were isolated by standard techniques and characterised by three colour flow cytometry. Interferon gamma (IFN-gamma) production was studied using the ELISPOT technique.

RESULTS

In patients with UC with pouchitis there was a significant increase in the CD4:CD8 ratio, expression of activation markers on CD3+ cells, and number of IFNgamma producing mononuclear cells compared with patients with UC without pouchitis (CD4:CD8 ratio 1.3 (range 0.7-2.7) versus 0.6 (0. 1-1.0), p=0.012). In addition, a positive correlation between increased crypt depth and the number of CD4+ cells (r=0.57) was shown.

CONCLUSION

The observed increase in activated mucosal CD4+ T cells and IFN-gamma production might lead to mucosal destruction and crypt hyperplasia as seen in pouchitis.

Metabolic consequences of total colectomy

Colectomy is performed for inflammatory bowel disease, familial polyposis syndrome and colorectal carcinoma. Surgical procedures are ileostomy with or without pouch, ileorectal anastomosis or ileal pouch-anal anastomosis. One of the major functions of the intact large intestine is to absorb water and electrolytes. After colectomy, as much as 400-1000 ml of nearly isotonic ileostomy fluid may be excreted, resulting in a chronic salt and water depletion. This is compensated for by an activation of the renin-angiotensin-aldosterone system. Reduced urine volumes may cause kidney stones. Both dehydration and renal sodium retention are probably less frequent in patients with ileal pouch-anal anastomosis. Absorption of nutrients in general is not impaired by colectomy. The large intestine salvages energy from malabsorbed organic matter through absorption of the short-chain fatty acids produced in bacterial fermentation. In ileostomy patients, fermentation is negligible, which leads to a significant loss of energy in the ileostomy fluid. Pouches are colonized by a bacterial flora similar to colonic bacteria. In these patients conservation of energy from malabsorbed substrate may be similar to healthy subjects. Resection of ileum and bacterial colonization may lead to malabsorption of vitamin B12 and bile acids. The latter may cause increased incidence of biliary cholesterol stones. Pouchitis is a frequent problem which may be caused by a deficiency of short-chain fatty acids and glutamine in the pouch contents. It is concluded that although the colon is not essential as a digestive organ in man, colectomy results in a number of metabolic changes. The ileal pouch-anal anastomosis may in part substitute for the functions of the large intestine.

Intestinal permeability in the ileal pouch

BACKGROUND

Villous atrophy, mucin changes ('colonic metaplasia'), and chronic inflammation occur to varying degrees in all patients with ileal pouchanal anastomosis whereas acute inflammation (pouchitis) affects a subgroup of patients with prior ulcerative colitis.

AIM

To measure epithelial barrier function looking for possible functional adaptation in ileal 'pouch' mucosa.

PATIENTS

Patients with an ileal pouch prior to ileostomy closure (n = 12), functioning pouch (n = 14), pouchitis (n = 8), and ulcerative colitis (n = 12) were assessed.

METHODS

51Cr-EDTA was administered into the 'pouch' or rectum and urinary recovery over 24 hours was taken as an indication of permeability (barrier function). Histological analysis of 'pouch' biopsy specimens was undertaken.

RESULTS

Mucosal permeability is decreased from median 9.4% (range 5.4% to 39.1%) to 1.4% (range 0.38% to 2.2%) after ileostomy closure (p < 0.002) with levels being negatively correlated with two histological parameters of colonic metaplasia-mucin changes (p = 0.03) and villous atrophy (p = 0.05). Pouchitis was associated with increased permeability 5.9% (1.9% to 19.5%) compared with healthy 'pouch' 1.4% (0.35 to 2.2%) (p < 0.006).

CONCLUSION

Despite the presence of chronic inflammation in the mature 'pouch' functional adaptation with reduced permeability occurs in conjunction with colonic metaplasia.