Dysplasia is more common in the distal than proximal colon in ulcerative colitis surveillance

Pathology and Clinical Significance of Inflammatory Bowel Disease-Associated Colorectal Dysplastic Lesions

Timely diagnosis and effective management of colorectal dysplasia play a vital role in preventing mortality from colorectal cancer in patients with chronic inflammatory bowel disease. This review provides a contemporary overview of the pathologic and endoscopic classification of dysplasia in inflammatory bowel disease, their roles in determining surveillance and management algorithms, and emerging diagnostic and therapeutic approaches that might further enhance patient management.

The calcium-sensing receptor modulates the prostaglandin E2 pathway in intestinal inflammation

Introduction: The prostaglandin E2 (PGE2) pathway is one of the main mediators of intestinal inflammation. As activation of the calcium-sensing receptor (CaSR) induces expression of inflammatory markers in the colon, we assessed the impact of the CaSR on the PGE2 pathway regulation in colon cancer cells and the colon in vitro and in vivo. Methods and Results: We treated CaSR-transfected HT29 and Caco-2 colon cancer cell lines with different orthosteric ligands or modulators of the CaSR and measured gene expression and PGE2 levels. In CaSR-transfected HT29CaSR-GFP and Caco-2CaSR-GFP cells, the orthosteric CaSR ligand spermine and the positive allosteric CaSR modulator NPS R-568 both induced an inflammatory state as measured by IL-8 gene expression and significantly increased the expression of the PGE2 pathway key enzymes cyclooxygenase (COX)-2 and/or prostaglandin E2 synthase 1 (PGES-1). Inhibition of the CaSR with the calcilytic NPS 2143 abolished the spermine- and NPS R-568-induced pro-inflammatory response. Interestingly, we observed cell-line specific responses as e.g. PGES-1 expression was affected only in HT29CaSR-GFP but not in Caco-2CaSR-GFP cells. Other genes involved in the PGE2 pathway (COX-1, or the PGE2 receptors) were not responsive to the treatment. None of the studied genes were affected by any CaSR agonist in GFP-only transfected HT29GFP and Caco-2GFP cells, indicating that the observed gene-inducing effects of spermine and R-568 were indeed mediated by the CaSR. In vivo, we had previously determined that treatment with the clinically approved calcimimetic cinacalcet worsened symptoms in a dextran sulfate sodium (DSS)-induced colitis mouse model. In the colons of these mice, cinacalcet significantly induced gene expression of PGES-2 and the EP3 receptor, but not COX-2; while NPS 2143 increased the expression of the PGE2-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Importantly, neither treatment had any effect on the colons of non-DSS treated mice. Discussion: Overall, we show that activation of the CaSR induces the PGE2 pathway, albeit with differing effects in vitro and in vivo. This may be due to the different microenvironment in vivo compared to in vitro, specifically the presence of a CaSR-responsive immune system. Since calcilytics inhibit ligand-mediated CaSR signaling, they may be considered for novel therapies against inflammatory bowel disease.

Critical roles of bile acids in regulating intestinal mucosal immune responses

Bile acids are a class of cholesterol derivatives that have been known for a long time for their critical roles in facilitating the digestion and absorption of lipid from the daily diet. The transformation of primary bile acids produced by the liver to secondary bile acids appears under the action of microbiota in the intestine, greatly expanding the molecular diversity of the intestinal environment. With the discovery of several new receptors of bile acids and signaling pathways, bile acids are considered as a family of important metabolites that play pleiotropic roles in regulating many aspects of human overall health, especially in the maintenance of the microbiota homeostasis and the balance of the mucosal immune system in the intestine. Accordingly, disruption of the process involved in the metabolism or circulation of bile acids is implicated in many disorders that mainly affect the intestine, such as inflammatory bowel disease and colon cancer. In this review, we discuss the different metabolism profiles in diseases associated with the intestinal mucosa and the diverse roles of bile acids in regulating the intestinal immune system. Furthermore, we also summarize recent advances in the field of new drugs that target bile acid signaling and highlight the importance of bile acids as a new target for disease intervention.

Risk of colorectal cancer in a population-based study 20 years after diagnosis of ulcerative colitis: results from the IBSEN study

Objective

The association between ulcerative colitis (UC) and colorectal cancer (CRC) is widely accepted, although attenuated risk has been reported in recent years. Colonoscopic surveillance is recommended with intervals based on established clinical risk factors. Nevertheless, a significant number of patients develop interval cancers, indicating the need of improved individualised assessment. In the present study, we evaluated clinical risk factors associated with CRC during a prescheduled follow-up 20 years after diagnosis, the IBSEN study.

Design

A population-based inception cohort of patients diagnosed with inflammatory bowel disease from 1 January 1990 until 31 December 1993, prospectively followed at 1, 5, 10 and 20 years after diagnosis. A total of 517 patients with UC were included; 264 (51 %) men; median age at inclusion 37.4 years (4–88).

Results

The overall incidence of CRC was 1.6% (8/517) at a 20-year follow-up. The total lifetime risk of CRC prior to or after UC diagnosis was 2.3%. (12/517). Patients older than 70 years at diagnosis had a 15-fold higher risk of CRC compared with those diagnosed when younger than 40 years, with HR 15.68 (95% CI: 1.31 to 187.92). Neither sex, first-degree relative with CRC, extent of colitis nor primary sclerosing cholangitis affected the risk of CRC.

Conclusion

The risk of CRC in UC was low and comparable with the risk of CRC in the background population of Norway.

Meta-analysis of the association between appendiceal orifice inflammation and appendectomy and ulcerative colitis

OBJECTIVE

This study aimed to investigate the relationship between appendiceal orifice inflammation (AOI) and appendectomy and ulcerative colitis (UC) by a meta-analysis.

METHODS

Databases were thoroughly searched for studies on AOI and UC up to January 2016. Three comparisons were performed: a) whether the previous appendectomy was a risk factor of UC; b) influence of appendectomy on UC courses; c) influence of AOI on UC severity. Odds ratios (ORs) and 95% confidence intervals (CIs) were the effects sizes. The merging of results and publication bias assessment were performed by using RevMan 5.3. Sensitivity analysis was conducted using Stata 12.0.

RESULTS

Nineteen studies were selected in the present study. Results of comparison I showed that appendectomy was a protective factor of UC (OR = 0.44; 95% CI [0.30, 0.64]). Comparison II indicated appendectomy had no significant influence in the courses of UC (proctitis: OR = 1.03, 95% CI [0.74, 1.42]; left-sided colitis: OR = 1.01, 95% CI [0.73, 1.39]; pancolitis: OR = 0.92, 95% CI [0.59, 1.43]; colectomy: OR = 1.38, 95% CI [0.62, 3.04]). Comparison III indicated UC combined with AOI did not affect the courses of UC (proctitis: OR = 1.15, 95% CI [0.67, 1.98]; left-sided colitis: OR = 1.14, 95% CI [0.24, 5.42]; colectomy: OR = 0.36, 95% CI [0.10, 1.23]). Sensitivity analysis confirmed the robust of the results in the present study.

CONCLUSION

In conclusion, this meta-analysis indicated appendectomy can reduce the risk of UC. But appendectomy or AOI had no influence on the severity of the disease and the effect of surgical treatment.

DNA methylation patterns in ulcerative colitis-associated cancer: a systematic review

BACKGROUND

Evidence points to the role of DNA methylation in ulcerative colitis (UC)-associated cancer (UCC), the most serious complication of ulcerative colitis. A better understanding of the etiology of UCC may facilitate the development of new therapeutic targets and help to identify biomarkers of the disease risk.

METHODS

A search was performed in three databases following PRISMA protocol. DNA methylation in UCC was compared with sporadic colorectal cancer (SCRC), and individual genes differently methylated in UCC identified.

RESULTS

While there were some similarities in the methylation patterns of UCC compared with SCRC, generally lower levels of hypermethylation in promoter regions of individual genes was evident in UCC. Certain individual genes are, however, highly methylated in colitis-associated cancer: RUNX3, MINT1, MYOD and p16 exon1 and the promoter regions of EYA4 and ESR.

CONCLUSION

Patterns of DNA methylation differ between UCC and SCRC. Seven genes appear to be promising putative biomarkers.

The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease

Background

Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD.

Aim

The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone.

Methods

Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry.

Results

The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD.

Conclusions

Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.

White-Light or Narrow-Band Imaging Colonoscopy in Surveillance of Ulcerative Colitis: A Prospective Multicenter Study

BACKGROUND & AIMS

Early detection of neoplastic lesions is essential in patients with long-standing ulcerative colitis but the best technique of colonoscopy still is controversial.

METHODS

We performed a prospective multicenter study in patients with long-standing ulcerative colitis. Two colonoscopies were performed in each patient within 3 weeks to 3 months. In white-light (WL) colonoscopy, stepwise random biopsy specimens (4 biopsy specimens every 10 cm), segmental random biopsies (2 biopsy specimens in 5 segments), and targeted biopsy specimens were taken. In NBI colonoscopy, segmental and targeted biopsy specimens were taken. The sequence of WL and NBI colonoscopy was randomized.

RESULTS

In 36 of 159 patients enrolled (22.6%), 54 lesions with intraepithelial neoplasia (IN) were found (51 low-grade, 3 high-grade). In WL colonoscopy we found 11 IN in stepwise biopsy specimens, 4 in segmental biopsy specimens, and 15 in targeted biopsy specimens. In NBI colonoscopy 7 IN were detected in segmental biopsy specimens and 24 IN were detected in targeted biopsy specimens. Almost all IN were found with one technique alone (κ value of WL vs NBI, -0.86; P < .001). Statistically equivalent numbers of IN were found in NBI colonoscopy with targeted and segmental biopsy specimens as in WL colonoscopy with targeted and stepwise biopsy specimens, but with fewer biopsy specimens (11.9 vs 38.6 biopsy specimens, respectively; P < .001), and less withdrawal time was necessary (23 vs 13 min, respectively; P < .001).

CONCLUSIONS

Stepwise biopsy specimens are indispensable in WL colonoscopy. The combination of targeted and segmental biopsy specimens in the NBI technique is as sensitive as targeted together with stepwise biopsy specimens in WL colonoscopy, but requires fewer biopsy specimens and less time. The highest sensitivity should be reached by combining the WL and NBI techniques by switching between the modes.

Apolipoprotein A-I inhibits experimental colitis and colitis-propelled carcinogenesis

In both humans with long-standing ulcerative colitis and mouse models of colitis-associated carcinogenesis (CAC), tumors develop predominantly in the distal part of the large intestine but the biological basis of this intriguing pathology remains unknown. Herein we report intrinsic differences in gene expression between proximal and distal colon in the mouse, which are augmented during dextran sodium sulfate (DSS)/azoxymethane (AOM)-induced CAC. Functional enrichment of differentially expressed genes identified discrete biological pathways operating in proximal vs distal intestine and revealed a cluster of genes involved in lipid metabolism to be associated with the disease-resistant proximal colon. Guided by this finding, we have further interrogated the expression and function of one of these genes, apolipoprotein A-I (ApoA-I), a major component of high-density lipoprotein. We show that ApoA-I is expressed at higher levels in the proximal compared with the distal part of the colon and its ablation in mice results in exaggerated DSS-induced colitis and disruption of epithelial architecture in larger areas of the large intestine. Conversely, treatment with an ApoA-I mimetic peptide ameliorated the phenotypic, histopathological and inflammatory manifestations of the disease. Genetic interference with ApoA-I levels in vivo impacted on the number, size and distribution of AOM/DSS-induced colon tumors. Mechanistically, ApoA-I was found to modulate signal transducer and activator of transcription 3 (STAT3) and nuclear factor-κB activation in response to the bacterial product lipopolysaccharide with concomitant impairment in the production of the pathogenic cytokine interleukin-6. Collectively, these data demonstrate a novel protective role for ApoA-I in colitis and CAC and unravel an unprecedented link between lipid metabolic processes and intestinal pathologies.

Spatial modeling of colonic lesions with geographic information systems

BACKGROUND

Geographic information system (GIS) software has been used in health care systems to display and analyze spatial pattern of diseases and health services.

OBJECTIVES

This study was performed to assess spatial patterns of colon's pathologic lesions based on the pathologic reports and assess whether it is possible to use GIS software in health services.

PATIENTS AND METHODS

Archives of pathology of Namazi and Faghihi hospitals, two main referral centers of south-west of Iran, were obtained and reviewed between January 2009 and September 2011 for biopsy reports of patients who underwent colonoscopy. Abnormal biopsies were categorized into five different subgroups according to the type of pathologic specimens. By GIS, spatial patterns of colon biopsies were plotted in different maps and spatial auto-correlation of colon biopsies was calculated using the Moran's Index.

RESULTS

A total of 4815 biopsies from 2663 different patients were reviewed, 53.8% of which were men. Abnormal biopsies were 2781 of all specimens (57.8%). Neoplastic lesions, inflammatory bowel diseases and polyps were 9.3%, 19.3% and 29.2% of total biopsies, respectively. Pathologic biopsies were more common in the distal colon. Maps of all biopsies and maps of specific pathologies were manifested in GIS.

CONCLUSIONS

Our study showed that left-sided lesions are still more common in the Iranian population. On the other hand, surveying the right side of colon is as important as the distal part, which necessitates total colonoscopy.

Colorectal cancer in colitis: a relic of the past?

The incidence of dysplasia and colorectal cancer in patients with long-standing colitis seems to be decreasing and controversy surrounds our detection and management strategies. Dysplasia is rarer, flatter, and smaller than in previous decades. Current surveillance guidelines, onerous in terms of colonoscopic workload and an emphasis on random biopsies, have yet to be shown to prevent colon cancers and colon cancer death in these patients. The evidence base for adjunct techniques such as chromoendoscopy is strong but adoption has been slow. We need to better risk-stratify patients with colitis and direct diminishing medical resources accordingly. Modulating dysplasia and cancer risk will involve optimizing medical therapies and focusing our colonoscopic efforts on those who will most likely benefit.

Refractory distal ulcerative colitis: is proctocolectomy always necessary?

Refractory distal ulcerative colitis (RDUC) is defined as persistence of symptoms caused by endoscopically proven colonic inflammation located at the rectum or left colon despite oral/topical steroids and 5-ASA. RDUC affects a small subset of patients and is associated with chronic disabling symptoms and increased social/medical costs. Moreover, patients with long-standing ulcerative colitis (UC) carry an elevated risk of developing colorectal cancer and colonic mucosa high-grade dysplasia. Alternative medical strategies in steroid refractory disease are unlikely to provide durable remission in all patients, carry potential severe side effects and, as immunosuppressants, the risk of other neoplasms, and may increase the short-term complication rate when surgery is finally required. Restorative proctocolectomy with ileal pouch-anal anastomosis (RP-IPAA) allows the complete removal of the diseased rectum and colon, virtually eliminating the risk of malignant transformation and reestablishing intestinal continuity with continence preservation. Since the introduction of this surgical procedure, morbidity and mortality rates have been drastically reduced. Despite the still notable rate of surgical complications, long-term quality of life assessment has shown excellent results in nearly all patients who have undergone RP-IPAA, comparing well with the general population. Furthermore, when performed for distal UC, RP-IPAA produces similar surgical outcomes with respect to pancolitis. In conclusion, RP-IPAA should always be considered in patients with RDUC, and multidisciplinary counseling should provide patients clear information about the advantages of surgery and possible complications as well as the chance to achieve disease remission with medical therapy.

Relationship between methylation and colonic inflammation in inflammatory bowel disease

AIM: To investigate the relationship between the methylation status in the SLIT2 and TGFB2 promoters and colonic inflammation in inflammatory bowel disease patients.

METHODS: We evaluated the methylation status of 2 genes (SLIT2 and TGFB2) in 226 biopsies taken from 62 colonoscopies of 38 patients (29 ulcerative colitis and 9 Crohn’s colitis) using methylation-specific melting curve analysis. The relationships between methylation status and clinical, biological, endoscopic and histological activities were evaluated. Twenty-three of the 38 patients had a second colonoscopy and were included in a longitudinal analysis. Numerical results were given as the means ± SD of the sample and range, except when specified. Student t analysis, U Mann Whitney and ANOVA factor were used to compare the means. Qualitative results were based on the χ² test.

RESULTS: SLIT2 methylation was more frequent in samples with endoscopic activity than with endoscopic remission (55% vs 18%, P < 0.001). SLIT2 methylation was also higher in samples with acute inflammation (56.5%) than in samples with chronic (24%) or absent inflammation (15%) (P < 0.001). For TGFB2 methylation, the correlation was only significant with endoscopic activity. Methylation was higher in the distal colon for both genes (P < 0.001 for SLIT2 and P = 0.022 for TGFB2). In the multivariate analysis, only inflammation status (and not disease duration or extension) was independently associated with SLIT2 methylation [OR = 6.6 (95%CI: 1.65-27.36), P = 0.009]. In the longitudinal analysis, the maintenance of endoscopic remission was protective for methylation.

CONCLUSION: Endoscopic and histological inflammation are predictive for SLIT2 methylation.

Histological healing favors lower risk of colon carcinoma in extensive ulcerative colitis

AIM: To search for the answer in extensive ulcerative colitis as to whether histological inflammation persisting despite endoscopic mucosal healing serves to increase the risk of colon cancer (CC) or high grade dysplasia (HGD).

METHODS: This is a single center (Lenox Hill Hospital) retrospective cohort and descriptive study of extensive ulcerative colitis (UC) for 20 years or more with a minimum of 3 surveillance colonoscopies and biopsies performed after the first 10 years of UC diagnosis. Data analyzed included: duration of UC, date of diagnosis of (CC) or (HGD), number of surveillance colonoscopies, and biopsies showing histological inflammation and its severity in each of 6 segments when endoscopic appearance is normal. Two subgroups of patients were compared: group 1 patients who developed CC/HGD and group 2 patients who did not develop CC/HGD.

RESULTS: Of 115 patients with longstanding UC reviewed, 68 patients met the inclusion criteria. Twenty patients were in group 1 and 48 in group 2. We identified the number of times for each patient when the endoscopic appearance was normal but biopsies nevertheless showed inflammation. Overall, histological disease activity in the absence of gross/endoscopic disease was found in 31.2% (95%CI: 28%-35%) of colonoscopies performed on the entire cohort of 68 patients. Histological disease activity when the colonoscopy showed an absence of gross disease activity was more common in group 1 than group 2 patients, 88% (95%CI: 72%-97%) vs 59% (95%CI: 53%-64%). Only 3/20 (15%) of patients in group 1 ever had a colonoscopy completely without demonstrated disease activity (i.e., no endoscopic or histological activity) as compared to 37/48 (77%) of patients in group 2, and only 3.3% (95%CI: 0.09%-8.3%) of colonoscopies in group 1 had no histological inflammation compared to 23% (95%CI: 20%-27%) in group 2.

CONCLUSION: Progression to HGD or CC in extensive ulcerative colitis of long standing was more frequently encountered among those patients who demonstrate persistent histological inflammation in the absence of gross mucosal disease. Our findings support including the elimination of histological inflammation in the definition of mucosal healing, and support this endpoint as an appropriate goal of therapy because of its risk of increasing dysplasia and colon cancer.

European consensus on the histopathology of inflammatory bowel disease

The histologic examination of endoscopic biopsies or resection specimens remains a key step in the work-up of affected inflammatory bowel disease (IBD) patients and can be used for diagnosis and differential diagnosis, particularly in the differentiation of UC from CD and other non-IBD related colitides. The introduction of new treatment strategies in inflammatory bowel disease (IBD) interfering with the patients' immune system may result in mucosal healing, making the pathologists aware of the impact of treatment upon diagnostic features. The European Crohn's and Colitis Organisation (ECCO) and the European Society of Pathology (ESP) jointly elaborated a consensus to establish standards for histopathology diagnosis in IBD. The consensus endeavors to address: (i) procedures required for a proper diagnosis, (ii) features which can be used for the analysis of endoscopic biopsies, (iii) features which can be used for the analysis of surgical samples, (iv) criteria for diagnosis and differential diagnosis, and (v) special situations including those inherent to therapy. Questions that were addressed include: how many features should be present for a firm diagnosis? What is the role of histology in patient management, including search for dysplasia? Which features if any, can be used for assessment of disease activity? The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas.

Farnesoid X receptor expression is decreased in colonic mucosa of patients with primary sclerosing cholangitis and colitis-associated neoplasia

BACKGROUND

The expression and distribution of farnesoid X receptor (FXR) in colitis and colitis-associated neoplasia (CAN) is unknown. We investigated FXR expression in neoplastic and nonneoplastic tissue from ulcerative colitis (UC) patients, with or without primary sclerosing cholangitis (PSC), as well as the role of DNA methylation in FXR expression in colorectal cancer (CRC) cell lines.

METHODS

Samples from the right (RC) and left (LC) colon of patients with UC, with and without PSC, and with or without CAN, were stained by immunohistochemistry and scored semiquantitatively for nuclear FXR expression. FXR expression was analyzed by western blot and polymerase chain reaction (PCR) in nine different CRC cell lines before and after demethylation with 5-azacytidine.

RESULTS

In nondysplastic samples, FXR expression demonstrated a diminishing expression from proximal to distal colon (strong FXR expression: 39% RC samples vs. 14% LC samples; P = 0.007). With moderate-to-severe inflammation, FXR expression was almost always absent or weak in both UC and PSC-UC, regardless of location. With quiescent/mild inflammation, 56% of UC samples in the RC retained strong FXR expression versus 24% of PSC-UC samples (P= 0.017). FXR was absent in 72% of the neoplastic samples, with an inverse association with the grade of dysplasia. FXR expression was absent in all CRC cell lines, in some cases due to DNA methylation.

CONCLUSIONS

FXR expression is inversely correlated with neoplastic progression and severity of inflammation in UC. Patients with PSC-UC have diminished FXR expression in the proximal colon compared to UC patients. This finding could contribute to the higher risk of proximal neoplasia in PSC patients.