Ischaemia: a pathogenetic clue in diversion colitis?

Interaction between the intestinal flora and the severity of diversion colitis after low anterior resection of rectal cancer

Background

Diversion colitis (DC) is nonspecific inflammation of the distal intestinal mucosa following disruption of colonic continuity with colonic dysfunction. The colonscopic score is a good tool for differentiating the severity of patients with DC. At present, no studies have analyzed the pathogenesis of DC from the perspective of the diversity and and differences of intestinal flora.

Methods

Retrospective study: Clinical information were collected from patients with low rectal cancer admitted to the Department of Anorectal Surgery, Changzheng Hospital, from April 2017 to April 2019. These patients underwent laparoscopic low anterior resection (LAR) combined with terminal ileum enterostomy (dual-chamber). We used chi-square test to comparethe clinical baseline information, clinical symptoms, and colonscopic characteristics between different severity of DC. Propsective oberservational study: We recruited 40 patients with laparoscopic anterior low resection combined with terminal ileum enterostomy and they were further classified into mild group and severe group according to the scores of colonscopic examinations for DC. 16s-rDNA sequencing was carried out to analyze the diversity and and differences of intestinal flora in the intestinal lavage fluid of the two groups.

Results

In retrospective study, we found that age, BMI, history of diabetes, and symptoms associated with the stoma state were the independent risk factors that affect DC severity (P<0.05). Meanwhile, age, BMI, history of diabetes and colonscopic score were found to be independent risk factors affecting the severity of diarrhea after ileostomy closure surgery(P<0.05), which was consistent with our results of differentiating the severity of DC under endoscopy; In propsective oberservational study, 40 patients with low rectal cancer recruited by sample size calculation, 23 were in the mild group and 17 in the severe group. The results of 16s-rDNA sequencing showed that intestinal flora with high enrichment values primarily consisted of Bifidobacteriales and Prevotella in mild group, whereas that in the severe group consisted of Providencia and Dorea. The functional predictions on such two types of intestinal flora were mainly focused on lipid synthesis, glycan synthesis, metabolism, and amino acid metabolism pathways.

Conclusion

After ileostomy closure surgery, a series of severe clinical symptoms might appear in DC patients. There are significant differences in local and systemic inflammatory responses, composition of intestinal flora between DC patients with different colonscopic scores, which provide a basis for the clinical interventional treatment for DC in patients with permanent stoma.

Evaluation of sucralfate enema in experimental diversion colitis

Diversion colitis (DC) is an inflammatory disease that develops in segments with fecal diversion. Sucralfate (SCF) complex, which consists of sucrose octasulfate and polyaluminum hydroxide, has been demonstrated to be effective in the treatment of different forms of colitis. However, until now, the effects of SCF have not been evaluated in DC.

Objective to evaluate whether the use of enemas containing SFC improves histological findings in experimental DC.

Methods Thirty-six rats underwent right colon bypass procedure through the creation of a proximal colostomy and a distal mucous fistula. The animals were divided into two groups according to the euthanization procedure to be performed two to four weeks after surgery. Each experimental group was divided into three subgroups of six animals, which were submitted to daily application of enemas containing saline solution 0.9% or SCF at concentrations of 1.0 g/kg/day or 2.0 g/kg/day, respectively. The diagnosis of DC in segments with fecal diversion was established by histopathological study considering the following

variables epithelial loss, formation of crypt abscesses, the population of goblet cells, inflammatory infiltrate and presence of fibrosis. For statistical analysis, the nonparametric Mann-Whitney and Kruskal-Wallis tests were used, with a significance level of 5% (p <0.05).

Results It was observed that the daily application of SCF enemas decreased epithelial loss, formation of colon crypt abscesses, inflammatory infiltrate and tissue fibrosis (p <0.05), unrelated to time of intervention. The intervention with SCF preserves the goblet cell population. The effects of the substance on the preservation of colonic epithelium; the decrease in the inflammatory process and subsequent abscess formation in the colon crypts are associated with the concentration used, whereas tissue fibrosis decrease is associated with the concentration and time of intervention.

Conclusion Preventive application of SCF enemas reduces the inflammatory process in the colon with fecal diversion

Non-neoplastic colorectal disease biopsies: evaluation and differential diagnosis

A wide variety of non-neoplastic conditions may be encountered on colorectal biopsy encompassing idiopathic, infectious, vascular and immune-mediated aetiologies. Although interpretation of such biopsies may be challenging, appreciation of the dominant pattern of injury and subsequent host response may allow for a more focused histological diagnosis in the correct clinical and endoscopic setting. This article aims to provide a systematic, methodical approach to the assessment of such biopsies, concentrating mainly on diagnoses other than inflammatory bowel disease.

Effects of anti-TNF-α in experimental diversion colitis

Purpose:

To evaluate the effects of infliximab on the inflammation of the colonic mucosa devoid from fecal stream.

Methods:

Twenty-four rats were submitted to a Hartmann's procedure. They remained for 12 weeks with the fecal derivation to development of diversion colitis on excluded colorectal stump. After this period, they were divided into 3 groups: one group received intervention with saline (2.0 mL / week), other group infliximab at doses of 5 mg/kg/week and the other 10 mg/kg/week for five consecutively weeks. Concluded the intervention period, the animals were euthanized to remove colon segments with and without fecal stream. Colitis was diagnosed by histological analysis and the degree of inflammation by validated score. The neutrophilic infiltrate was evaluated by tissue expression of myeloperoxidase identified by immunohistochemical. The tissue content of myeloperoxidase was measured by computer-assisted image analysis.

Results:

The inflammatory score was high in colonic segments without fecal stream. The intervention with infliximab reduced the inflammatory score in excluded colonic segments. The content of myeloperoxidase was reduced in colonic segments of animals treated with infliximab mainly in high concentrations.

Conclusion:

Intervention with infliximab reduced the inflammation and the neutrophil infiltrate in colonic segments devoid of the fecal stream.

A case of severe megacolon due to acquired isolated hypoganglionosis after low anterior resection for lower rectal cancer

Acquired isolated hypoganglionosis is a rare intestinal neurological disease, which presents in adulthood with the clinical symptoms of chronic constipation. A 39-year-old man underwent laparoscopic low anterior resection and covering ileostomy for locally advanced-rectal cancer. A 6-month course of postoperative adjuvant chemotherapy was completed, followed by closure of the ileostoma. After the closure, he developed severe colitis which required 1-month of hospitalization. Mucosal erosions and pseudo-membrane formation were evident on colonoscopy and severe mucosal damage characterized by infiltration of inflammatory cells and crypt degeneration were pathologically confirmed. Even after the remission of the colitis, he suffered from severe constipation and distention. At 4 years after the stoma closure, he decided to undergo laparoscopic total colectomy. Histopathologically, the nerve fibers and ganglion cells became gradually scarcer from the non-dilated to dilated regions. Immunohistochemical staining examination confirmed that the ganglion cells gradually decreased and became degenerated from the normal to dilated region, thereby arriving at the final diagnosis of isolated hypoganglionosis. The patient recovered without any complications and there has been no evidence of any relapse of the symptoms. We present a case of acquired isolated hypoganglionosis-related megacolon, which required laparoscopic total colectomy, due to severe enterocolitis following stoma closure.

Diversion colitis and pouchitis: A mini-review

Diversion colitis is characterized by inflammation of the mucosa in the defunctioned segment of the colon after colostomy or ileostomy. Similar to diversion colitis, diversion pouchitis is an inflammatory disorder occurring in the ileal pouch, resulting from the exclusion of the fecal stream and a subsequent lack of nutrients from luminal bacteria. Although the vast majority of patients with surgically-diverted gastrointestinal tracts remain asymptomatic, it has been reported that diversion colitis and pouchitis might occur in almost all patients with diversion. Surgical closure of the stoma, with reestablishment of gut continuity, is the only curative intervention available for patients with diversion disease. Pharmacologic treatments using short-chain fatty acids, mesalamine, or corticosteroids are reportedly effective for those who are not candidates for surgical reestablishment; however, there are no established assessment criteria for determining the severity of diversion colitis, and no management strategies to date. Therefore, in this mini-review, we summarize and review various recently-reported treatments for diversion disease. We are hopeful that the information summarized here will assist physicians who treat patients with diversion colitis and pouchitis, leading to better case management.

Deviation of the Fecal Stream in Colonic Bowel Segments Results in Increased Numbers of Isolated Lymphoid Follicles in the Submucosal Compartment in a Novel Murine Model of Diversion Colitis

INTRODUCTION

Diversion colitis is a significant health problem due to its high incidence in patients with diverting enterostomy. This mucosal inflammation presents characteristic histopathological features allowing for the differentiation of this entity from other inflammatory bowel diseases. The pathophysiology of this disease remains ill-defined, in part due to the lack of appropriate animal models. The present study was performed in order to develop and characterize a murine model of diversion colitis.

METHODS

A diverting loop colostomy was performed in C57BL/6 mice either in the ascending colon or in the transverse colon. Animals were assessed for clinical and histopathological parameters during short-term and long-term survival.

RESULTS

Animals with a colostomy in the transverse colon showed a good long-term survival and developed a mild colitis in the bypassed bowel closely resembling the human pathology on a histopathological level.

CONCLUSION

This model is a promising tool to further elucidate the pathomechanism leading to impaired mucosal homeostasis in bypassed colonic segments. Moreover, the establishment of the model in the C57BL/6 background allows the combination of this colitis model with various transgenic mouse strains to investigate the effect of locally deregulated mucosal immunity on systemic immune homeostasis and to develop specific therapeutic strategies.

Pathophysiology, clinical presentation and management of diversion colitis: a review of current literature

INTRODUCTION

Diversion colitis is a non-specific inflammation of a de-functioned segment of intestine after diversion of the faecal stream.

AIM

The aim of this study was to review the current level of knowledge about diversion colitis.

METHODS

A literature search of relevant literature in the English language was carried out on PUBMED, MEDLINE and EMBASE. The following keywords were used: diversion colitis; disuse colitis; proctitis; colonic bacterial flora; stoma; de-functioned colon; faecal diversion; short chain fatty acids and lymphoid follicular hyperplasia.

RESULTS

In total 35 articles met the inclusion criteria. 22 were case series, 9 were case reports, 2 were retrospective analysis and 2 were prospective randomized controlled studies. Diversion colitis is invariably present in all diverted segments of the colon. It is usually asymptomatic but can present with tenesmus, rectal discharge, bleeding per rectum and abdominal pain. Major macroscopic changes include mucosal nodularity, erythema and friability. Microscopic features are predominantly those of lymphoid follicular hyperplasia, apthous ulceration and chronic inflammatory changes, mostly limited to sub mucosa. Treatment modalities include surveillance for asymptomatic patients, restoration of bowel continuity for severely symptomatic cases and the use of short chain fatty acid (SCFA) enemas in selected cases.

CONCLUSION

The clinical presentation of diversion colitis varies significantly. In symptomatic patients short chain fatty acid enema may help. Further prospective studies are required for evaluation.

Enemas with N-acetylcysteine can reduce the level of oxidative damage in cells of the colonic mucosa diverted from the faecal stream

BACKGROUND

Oxidative stress has been related to inflammation of the colonic mucosa in patients with diversion colitis (DC).

AIM

The purpose of this study was to evaluate the antioxidants effects of n-acetylcysteine (NAC) in colon segments without faecal stream.

METHODS

Thirty-six Wistar rats were subjected to diversion of the faecal stream by proximal colostomy and a distal mucosal colon fistula. They were distributed into three experimental groups of 12 animals each; the animals in each group underwent daily enemas containing saline solution (control group) or either a 25 or 100 mg/kg dose of NAC (treated groups). In each group, animals were sacrificed after 2 or 4 weeks. The degree of inflammation was determined by histopathological analysis and stratified by inflammatory grading scale. Oxidative DNA damage was measured by comet assay. The Mann-Whitney test and ANOVA were used for statistical analysis; p<0.05 was considered significant.

RESULTS

The oxidative DNA damage in colon segments without faecal stream was significantly lower in animals treated with either concentration of NAC than in control group, regardless of the duration of intervention (p<0.01).

CONCLUSIONS

Intrarectal application of NAC reduces the inflammation as well as DNA oxidative damage and could be beneficial as a complementary agent in the treatment of DC.

Prevalence of Clostridium Difficile in Excluded Colons

Clostridium difficile infection is associated with substantial morbidity and mortality, increased duration of hospitalization, and a marked economic impact. Several case reports and case series have described C. difficile infection in excluded bowels or immediately after reversal of defunctioning ileostomy. The aim of this prospective study is to detect whether the excluded colon is associated with a higher rate of C. difficile colonization than the normal population, which may increase the risk of C. difficile infection. Patients with defunctioning loop ileostomy, undergoing closure of ileostomy to restore bowel continuity, were prospectively recruited. Two stool samples were collected from the ileostomy effluent before closure of ileostomy and two after the procedure including the first bowel movement. All samples were cultured for C. difficile and analyzed for toxins A and B by a Premier EIA test. Demographic data and possible confounding factors were observed and recorded. Twenty-fine adult patients were recruited to this study; five patients were subsequently excluded. Two patients had positive stool cultures for C. difficile in the postoperative samples and another patient developed clinical pseudomembranous colitis with positive toxin. This indicates a possible colonization rate of 3 to 38 per cent (95% confidence interval). Four observed cases out of the 20 subjects taking part in this study would confidently conclude that C. difficile colonization in the excluded colon is 6 to 44 per cent, i.e., higher than the incidence in the healthy adult population, which is 3 per cent. However, the findings of this study prompt larger and well-powered studies to confirm these findings.

The importance of oxygen free radicals in the etiopathogenesis of diversion colitis in rats

PURPOSE

Quantify the levels of oxidative DNA damage of epithelial colon cells comparing segments with and without fecal stream.

METHODS

Sixty Wistar rats were subjected to deviation of fecal stream by proximal colostomy and a distal mucosal fistula. Animals were divided into three experimental groups that were sacrificed 6, 12 and 24 weeks after surgery. In each experimental group, five animals underwent laparotomy without intestinal deviation (sham subgroup). The diagnosis of colitis was made by histopathological analysis and the inflammatory activity index by graduated scale. The neutrophil infiltration was determined by myeloperoxidase tissue levels and the intensity of oxidative DNA damage by comet assay. The Mann-Withney and Student t test were used to compare the results among experimental subgroups and the Kruskal-Wallis test for variance analysis, adopting a significance level of 5% (p<0.05).

RESULTS

Colon segments without fecal stream was shown higher histological inflammatory score of the colon wall after 12 and 24 weeks (p=0.001) that increased with the time of diversion (p=0.01). The activity of myeloperoxidase in segments without fecal stream decreased with the time (p=0.001). Oxidative DNA damage levels were significantly higher in the segments without fecal stream, (p=0.0001), independent of time of colon diversion, and increase with the time (p=0.0007).

CONCLUSIONS

Colon segments without fecal stream showed high levels of oxidative DNA damage related to histological alterations observed in diversion colitis. The levels of oxidative DNA damage in segments devoid of the fecal stream increase with the time of intestinal exclusion.

5-aminosalicylic acid (5-ASA) can reduce levels of oxidative DNA damage in cells of colonic mucosa with and without fecal stream

BACKGROUND

No studies have evaluated the effectiveness of 5-ASA against oxidative DNA damage in experimental models of diversion colitis.

AIM

To evaluate the effects of 5-ASA against oxidative DNA damage in an experimental model of diversion colitis.

METHODS

Twenty-six Wistar rats were divided into two groups corresponding to sacrifice at 2 or 4 weeks after fecal diversion of the left colon by means of proximal colostomy and distal mucosa fistula. Each group was divided into two subgroups according to intervention in excluded colon performed with 0.9% saline solution or 5-ASA. Level of oxidative DNA damage was determined by comet assay in cells obtained from segments with and without fecal stream before and after H2O2 challenge. For statistical analysis, was used one-way analysis of variance (ANOVA), adopting a 5% significance level (P<0.05).

RESULTS

Levels of DNA damage were always higher in colon segments without fecal stream, regardless of the intervention solution employed. DNA damage in colon segments with and without fecal stream in animals irrigated with 5-ASA was lower when compared with those treated with saline solution, regardless of time of irrigation. These levels remained lower after intervention with 5-ASA, even after H2O2 challenge.

CONCLUSIONS

Enema with 5-ASA reduces oxidative DNA damage in epithelial cells of colon segments without fecal stream, even after H2O2 challenge, confirming the effects of 5-ASA against DNA damage by oxygen free radicals.

Inflammatory alterations in excluded colon in rats: a comparison with chemically induced colitis

Diversion colitis occurs commonly in the large bowel remnant after diversion of the fecal stream. Several experimental models of colitis have been described, but none examine the inflammatory alterations that can occur in experimentally defunctioned colons. This characterization could be useful in understanding pathophysiological aspects of diversion colitis, and in developing future therapeutic strategies. Thus, we evaluated the temporal inflammatory alterations in the defunctioned colon of rats by analyzing the histological results, infiltrating neutrophils, pro-inflammatory markers such as cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS), and DNA damage in isolated colonocytes. We compared the obtained data with those from hapten-induced colitis. The experimental diversion of the colon fecal stream induces diversion colitis characterized by an early inflammatory process with increased neutrophil infiltrate, and COX-2 and iNOS expression that resembles, in some aspects, the inflammatory characteristics of chemically induced colitis. After acute inflammation resolution, there was an increase in COX-2 and iNOS expression and the presence of lymphoid follicular hyperplasia and ulcerations, suggesting that diversion colitis can be experimentally established and useful for studying different pathophysiological aspects of this condition.

How to treat diversion colitis?--Current state of medical knowledge, own research and experience

The aim of this study was to present current knowledge about a nospecific inflammation of mucosa within segments of colon excluded from normal bowel passage called as a "diversion colitis" (DC) and to try to determine the role of factors which might modify the clinical course of DC. We also unswered the question; how to treat DC: conservatively or surgically? Our own experience with DC concerns 145 patents (which is most numerous and well exactly examined series presented in literature). In the group of patients studied, clinical signs of DC were present in over 70% of patients (early signs were low abdominal pain and tenesmus, while anal oozing appeared later). Predominating endoscopic features of DC in the group of patients studied were: a. blurring of vascular pattern (in app. 90% of patients); b. contact bleeding (in app. 80% of patients); c. mucosal oedema (in app. 60% of patients). Results of own observations and literature data indicate, that morphologic alterations in the segment of bowel excluded from normal passage are probably vasogenic consisting in atrophy and inflammation of the allergic type (this would confirm the theory about vascular etiology of DC). In our material, we have not noticed any trend toward hyperproliferation or dysplasia in the excluded segment of colon, supporting the thesis that these disturbances are largely reversible. Clinical pathology of DC does not depend on age, sex, cause and type of surgical procedure performed, mode of surgery or concomitant diseases. Authors suggested an alternative algorithm of diagnostic work-up in patients suspected of DC, and proposed that patients with a segment of bowel excluded from normal passage be subdivided into three groups: 1. Patients with no clinical, endoscopic nor morphologic signs of DC. 2. Patients with moderate signs of DC. 3. Patients with severe signs of DC. Patients in the group 1 should remain under continuous specialised supervision, because they are at risk of developing DC, while patients in the groups 2 and 3 should undergo surgical restoration of bowel continuity. This applies particularly to group 3, where indications for surgery do not stem from risk of hyperproliferation, dysplasia or malignant transformation, but from that of a massive inflammation, which may constitute a danger for patientis health and even life. Authors also underline that DC can be treated conservatively but the best and most successful and remained method of treatment of DC is the operation of decolostomy, which means restoration continuity of digestive tract.

A case of fulminant diversion pan-colitis presenting 19 years after colonic diversion for neuronal intestinal dysplasia

A 20-year old woman with a long history of abdominal symptoms presented with acute abdominal pain associated with nausea and vomiting. She had had a right iliac fossa end-ileostomy previously fashioned at the age of 11 months for neuronal intestinal dysplasia. A few days after her admission she suffered a hypokalaemic cardiac arrest from which she was resuscitated. Her clinical condition deteriorated as she became increasingly septic. She was diagnosed with a fulminant colitis based on the clinical picture and the finding of fluid filled, thick walled rectum suggestive of proctocolitis on a pelvic magnetic resonance imaging scan. She was taken to the operating theatre where she had a subtotal colectomy. The histopathological diagnosis was that of fulminant diversion colitis. The patient recovered from surgery and was discharged home 5 weeks later.