Short-chain fatty acids in the non-adapted and adapted pelvic ileal pouch

Endoscopic Evaluation of the Ileal Pouch

BACKGROUND

Structural and inflammatory adverse sequelae are common after restorative proctocolectomy and IPAA. On rare occasions, neoplasia can occur in patients with ileal pouches. Pouchoscopy plays a key role in the diagnosis, differential diagnosis, disease monitoring, assessment of treatment response, surveillance, and delivery of therapy.

OBJECTIVE

A systematic review of the literature was performed, and principles and techniques of pouchoscopy were described.

DATA SOURCES

PubMed, Google Scholar, and Cochrane databases.

STUDY SELECTION

Relevant articles on endoscopy in ileal pouches published between January 2000 and May 2023 were included based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

INTERVENTION

Diagnostic, surveillance, and therapeutic endoscopy in ileal pouch disorders were included.

MAIN OUTCOME MEASURES

Accurate characterization of the ileal pouch in healthy or diseased states.

RESULTS

The main anatomic structures of a J- or S-pouch are the stoma closure site, prepouch ileum, inlet, tip of the "J," pouch body, anastomosis, cuff, and anal transition zone. Each anatomic location can be prone to the development of structural, inflammatory, or neoplastic disorders. For example, ulcers and strictures are common at the stoma closure site, inlet, and anastomosis. Leaks are commonly detected at the tip of the "J" and anastomosis. Characterization of the anastomotic distribution of inflammation is critical for the differential diagnosis of subtypes of pouchitis and other inflammatory disorders of the pouch. Neoplastic lesions, albeit rare, mainly occur at the cuff, anal transition zone, or anastomosis.

LIMITATIONS

This is a qualitative, not quantitative, review of mainly case series.

CONCLUSIONS

Most structural, inflammatory, and neoplastic disorders can be reliably diagnosed with a careful pouchoscopy. The endoscopist and other clinicians taking care of pouch patients should be familiar with the anatomy of the ileal pouch and be able to recognize common abnormalities. See video from symposium.

Role of short-chain fatty acids in colonic inflammation, carcinogenesis, and mucosal protection and healing

Short-chain fatty acids (SCFAs), mainly acetate, propionate, and butyrate, produced by microbial fermentation of undigested food substances are believed to play a beneficial role in human gut health. Short-chain fatty acids influence colonic health through various mechanisms. In vitro and ex vivo studies show that SCFAs have anti-inflammatory and anticarcinogenic effects, play an important role in maintaining metabolic homeostasis in colonocytes, and protect colonocytes from external harm. Animal studies have found substantial positive effects of SCFAs or dietary fiber on colonic disease, but convincing evidence in humans is lacking. Most human intervention trials have been conducted in the context of inflammatory bowel disease. Only a limited number of those trials are of high quality, showing little or no favorable effect of SCFA treatment over placebo. Opportunities for future research include exploring the use of combination therapies with anti-inflammatory drugs, prebiotics, or probiotics; the use of prodrugs in the setting of carcinogenesis; or the direct application of SCFAs to improve mucosal healing after colonic surgery.

Laboratory tests for patients with ileal pouch-anal anastomosis: clinical utility in predicting, diagnosing, and monitoring pouch disorders

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the surgical treatment of choice for patients with medically refractory ulcerative colitis (UC) or UC-associated dysplasia, and for the majority of patients with familial adenomatous polyposis. Pouchitis and other complications of IPAA are common. There are scant data on laboratory markers for the evaluation and diagnosis of pouch disorders. The presence of immunogenotypic markers such as genetic polymorphisms of interleukin-1 (IL-1) receptor antagonist, NOD2/CARD15, Toll-like receptor, and tumor necrosis factor-alpha has been reported to be associated with pouchitis. Immunophenotypic/serologic markers such as perinuclear antineutrophil cytoplasmic antibody and anti-CBir1 have been investigated as possible markers for predicting and diagnosing pouchitis. Fecal markers including lactoferrin and calprotectin seem to be useful in distinguishing inflammatory from noninflammatory pouch disorders. In our practice, we have encountered a large number of pouch patients with Clostridium difficile infection. Laboratory evaluation provides information on the etiology and pathogenesis of pouchitis, and it also helps practicing clinicians with accurate diagnosis, differential diagnosis, disease stratification, and management of ileal pouch disorders.

Bacterial population moves toward a colon-like community in the pouch after total proctocolectomy

BACKGROUND

Colonic transformation is defined by phenotypic alterations in the ileum after total proctocolectomy. Changes in microbiota of the ileal pouch and the roles of these microbes in colonic transformation, however, have not been addressed.

METHODS

A total of 151 stool samples were collected from patients with ulcerative colitis patients and an ileostomy, those with an ileal pouch, and healthy control volunteers. Bacterial DNA was extracted from stool, and the diversity of complex bacteria was assessed by terminal restriction fragment length polymorphism (T-RFLP) analysis, a novel DNA-based approach that enables us to investigate the presence of nonculturable bacteria. To determine whether ileal pouch bacterial communities shift to a more colon-like distribution, the relative abundance of terminal restriction fragments that could be classified as "colonic," "ileal," or "common" was investigated.

RESULTS

Cluster analysis demonstrated that most of the ileostomy samples were categorized into Cluster I or II and that less than 10% of ileostomy samples were classified into Cluster IV. In contrast, more than 90% of control samples were grouped in Cluster IV. In further analyses, the median lifetimes of pouches in Clusters I, II, III, and IV were significantly different at 11, 56, 265, and 310 days, respectively. T-RFLP patterns of the ileal pouch were characterized by a time-dependent decrease in "ileal" and increase in a part of "colonic" fragments, which represented mainly nonculturable bacteria such as the Clostridium coccoides group.

CONCLUSION

T-RFLP analysis demonstrated that a time-dependent shift to a "colon-like" bacterial community, including nonculturable bacteria, in the ileal pouch after total proctocolectomy.

Working capacity and resting energy expenditure after ileal pouch-anal anastomosis

BACKGROUND

The aim was to evaluate the working capacity and resting energy expenditure in patients who had undergone restorative proctocolectomy.

METHODS

Of 72 patients operated on between April 1990 to September 1998, 51 were eligible and 38 participated in the study. Resting energy was assessed by indirect calorimetry, and working capacity by ergospirometry on an exercise bicycle.

RESULTS

The median functional score was 2 (range 0-7). Oxygen uptake during rest was reduced for men compared with predicted values. The corresponding values for women were in keeping with predicted values. The median working capacity was 96 (range 59-102) per cent for women and 91 (range 51-113) per cent for men, compared with reference values of maximum workload based on age, height and sex. There was no correlation between functional score and any other variable measured.

CONCLUSION

Patients who have undergone restorative proctocolectomy for ulcerative colitis have normal resting energy expenditure and working capacity.

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.

Functional and morphologic changes of the ileal mucosa after ileoanal pouch procedure

BACKGROUND

Restorative proctocolectomy is used widely for treatment of ulcerative colitis and familial polyposis coli. Limited information is available regarding the morphologic and functional adaptation of the mucosa in a functioning ileoanal pouch.

STUDY DESIGN

Ileal pouch specimens from patients who underwent pouch reconstruction (mean 7.5 years postcolectomy, n = 12) were compared with normal ileum (n = 15) and normal colon (n = 5). Amino-oligopeptidase (AOP) and maltase activity were measured as parameters of normal ileal function. Histologic samples were examined for the presence of neutrophils and plasma cells, the villus to crypt height ratio, and the degree of crypt hyperplasia, villus blunting, and goblet cell mass. Data were analyzed by analysis of variance.

RESULTS

The AOP activity in the normal ileum was 73 +/- 32 units of enzymatic activity per gram of mucosal protein; the AOP activities of the pouch and colon were 21 +/- 22 and 16 +/- 10, respectively. The maltase activity of the normal ileum measured 254 +/- 116 units of enzymatic activity per gram of mucosal protein, and the maltase activities of the pouch and colon were 57 +/- 71 units and 29 +/- 25 units, respectively. The ileal pouch mucosa demonstrated little acute inflammation and varying degrees of chronic inflammation. Morphologically, the ileal pouch mucosa demonstrated a range of adaptations, including villus blunting and crypt hyperplasia. Several specimens contained immature epithelial cells.

CONCLUSIONS

The AOP and maltase activities in mucosa from ileoanal pouches and colon were significantly lower than those in normal ileal mucosa. Ileoanal pouch mucosa from humans undergoes adaptive changes to resemble colonic mucosa both morphologically and functionally.

Ileal pouches: adaptation and inflammation

Ileal pouch-anal anastomosis (IPAA) has become the operation of choice following proctocolectomy for ulcerative colitis (UC) and familial adenomatous polyposis. Functioning ileal pouch mucosa undergoes histological changes resembling the colon (colonic metaplasia). The possible role of stasis and luminal factors--bile acids, short-chain fatty acids and bacteria--are discussed. It seems likely that colonic metaplasia is an adaptive response to the new luminal environment in IPAA. Inflammation in the ileal reservoir ('pouchitis') is the most significant late complication in IPAA. It occurs in 20-30% of patients and is virtually confined to those with prior UC. The clinical picture in pouchitis is highly variable; however, it can be easily categorized into three groups. Nevertheless, in most cases it is likely to represent recurrent UC in the ileal pouch. Current treatments and possible preventative strategies for pouchitis have been outlined.