Collagenous Colitis Is Associated With HLA Signature and Shares Genetic Risks With Other Immune-Mediated Diseases

BACKGROUND & AIMS

Collagenous colitis (CC) is an inflammatory bowel disorder with unknown etiopathogenesis involving HLA-related immune-mediated responses and environmental and genetic risk factors. We carried out an array-based genetic association study in a cohort of patients with CC and investigated the common genetic basis between CC and Crohn's disease (CD), ulcerative colitis (UC), and celiac disease.

METHODS

DNA from 804 CC formalin-fixed, paraffin-embedded tissue samples was genotyped with Illumina Immunochip. Matching genotype data on control samples and CD, UC, and celiac disease cases were provided by the respective consortia. A discovery association study followed by meta-analysis with an independent cohort, polygenic risk score calculation, and cross-phenotype analyses were performed. Enrichment of regulatory expression quantitative trait loci among the CC variants was assessed in hemopoietic and intestinal cells.

RESULTS

Three HLA alleles (HLA-B∗08:01, HLA-DRB1∗03:01, and HLA-DQB1∗02:01), related to the ancestral haplotype 8.1, were significantly associated with increased CC risk. We also identified an independent protective effect of HLA-DRB1∗04:01 on CC risk. Polygenic risk score quantifying the risk across multiple susceptibility loci was strongly associated with CC risk. An enrichment of expression quantitative trait loci was detected among the CC-susceptibility variants in various cell types. The cross-phenotype analysis identified a complex pattern of polygenic pleiotropy between CC and other immune-mediated diseases.

CONCLUSIONS

In this largest genetic study of CC to date with histologically confirmed diagnosis, we strongly implicated the HLA locus and proposed potential non-HLA mechanisms in disease pathogenesis. We also detected a shared genetic risk between CC, celiac disease, CD, and UC, which supports clinical observations of comorbidity.

A simple tissue-handling technique performed in the endoscopy suite improves histologic section quality and diagnostic accuracy for serrated polyps

BACKGROUND AND STUDY AIMS

Surveillance intervals after colonoscopic resection of serrated polyps are partially predicated on the histology of the polyp(s) removed during the index exam. Histologic discrimination between sessile serrated adenomas/polyps (SSA/P) and hyperplastic polyps is challenging. We devised and tested a simple tool--an envelope--that gastroenterologists can integrate into routine colonoscopy practice to address this problem.

METHODS

In the "modified protocol," immediately after polypectomy each serrated polyp was flattened and enclosed in a paper envelope before being placed in formalin. In the pathology laboratory, each polyp was sectioned after processing. A two-site, prospective, randomized, single-blinded trial was performed to compare this modified protocol with the conventional protocol. Serrated polyps located proximal to the splenic flexure and 5-20 mm in diameter were included. A novel orientation score that measured the number of well-oriented crypts per unit area of polyp (higher orientation score = better orientation) was validated. Orientation score, SSA/P diagnosis rate, and inter-pathologist agreement were measured.

RESULTS

A total of 375 polyps were enrolled, of which 264 were identified for analysis. The mean orientation scores in the modified and conventional protocol groups were 3.11 and 1.13, respectively (P < 0.0001). SSA/Ps were diagnosed in 103/135 cases (76.3%) in the modified protocol group vs. 54/129 (41.9%) in the conventional protocol group (P < 0.0001). Inter-pathologist agreement was higher with the modified than the conventional protocol (77.0% vs. 62.8%; P = 0.015).

CONCLUSION

Standard polyp handling techniques may be sub-optimal for interpretation of serrated polyps resected at colonoscopy, and may lead to inadvertent histologic "under-grading" of many lesions. Our intervention improved histopathologic interpretation and increased the SSA/P diagnosis rate.

Clinical predictors of inflammatory bowel disease in a genetically well-defined Caucasian population

Background

Crohn's disease (CD) and ulcerative colitis (UC), the two main types of inflammatory bowel disease (IBD), are multifactorial conditions of unknown etiology. The objective of this study is to examine the combined gene-environment interactions influencing IBD susceptibility in a well-defined Caucasian cohort in rural mid-America.

Methods

Patients were diagnosed to have CD or UC using conventional radiologic, endoscopic, and/or histopathologic findings. Histological diagnosis was made by a single specialist gastrointestinal pathologist with a particular interest in IBD. Information regarding cigarette smoke exposure was obtained by administration of the Behavioral Risk Factor Surveillance System Survey (BRFSS) to all patients. Genomic DNA was extracted from peripheral blood leukocytes, and polymerase chain reaction (PCR) amplification and genotyping were performed for 11 Single Nucleotide Polymorphisms (SNP) in NOD2, IL23r, OCTN1 genes along with IGR.

Results

Our cohort consists of 1196 patients: 435 controls, 485 CD patients, and 276 UC patients. Only patients with genotype data for at least 7 of 11 SNPs were included in our data analysis. The control groups for all 11 SNPs were in Hardy-Weinberg Equilibrium. In genotype-association SNP analysis, all NOD2 SNPs (rs5743293, rs2066844, rs2066845) and the IL23r SNP (rs11465804) showed a significant association to IBD (p < 0.03). A multiple gene-interaction analysis showed an association between NOD2 and IL23r with UC (p = 0.04). There were no associations between any OCTN1 and IGR SNPs and IBD in this cohort. A multivariable logistic regression analysis showed that female gender, "current" or "former" smoking status, family history of IBD, and NOD2 SNP minor alleles were associated with CD.

Conclusion

IBD remains to be challenging to properly diagnose, characterize, and treat. Our study proposes a combined genetic, phenotypic, and environmental approach in an attempt to better understand IBD. Previously demonstrated associations between OCTN1 and IGR and IBD were not confirmed.

Interobserver and intraobserver bias exists in the interpretation of anal dysplasia

INTRODUCTION

Natural history of progression from anal intraepithelial neoplasia to invasive carcinoma remains unproven. The risk of progression may be linked to the severity of dysplasia. Important therapeutic decisions are thus based on the severity of anal intraepithelial neoplasia. Consistency and reliability in the interpretation of anal intraepithelial neoplasia are unproven.

METHODS

One hundred ninety anal biopsy specimens were identified for review of dysplasia with a six-point grade system from normal to invasive cancer, evidence of human papillomavirus infection, and quality of histology by three pathologists.

RESULTS

Results revealed poor to moderate agreement on grading of quality of histology (weighted kappa score, 0.07-0.22), human papillomavirus status (weighted kappa score, 0.24-0.53), and dysplasia (weighted kappa score, 0.38-0.7). Complete agreement between the original pathology and the three pathologists was observed in only 32 percent of cases. Analysis of 86 slides previously read by one of the pathologists revealed only moderate agreement, with a weighted kappa score of 0.64.

CONCLUSION

Significant interobserver and intraobserver bias exists in the interpretation of anal intraepithelial neoplasia. These inconsistencies may explain the uncertainty about the natural progression of anal intraepithelial neoplasia and the varied results of surgery reported for anal intraepithelial neoplasia in the literature.

Characterization and clinical behavior of Crohn's disease initially presenting predominantly as colitis

PURPOSE

We studied patients with Crohn's disease affecting the colon to characterize disease behavior and to determine whether such patients might be candidates for sphincter-sparing surgery.

METHODS

Ninety-two consecutive patients with Crohn's colitis were studied prospectively. Mean follow-up after diagnosis was 82 (range, 6-291) months. Parameters that were evaluated included previous surgery for Crohn's disease, granulomatous vs. nongranulomatous disease, extent of colonic involvement, and presence or absence of extracolonic disease. The clinical course of the disease and postoperative outcome were evaluated. The outcome of Crohn's colitis patients who underwent ileal pouch-anal anastomosis for presumed ulcerative colitis was also evaluated.

RESULTS

There were 39 patients with granulomatous colitis and 53 patients without granulomas. There was no statistical difference in the age of diagnosis or presence of small-bowel (23 vs. 27 percent), ileocolic (34 vs. 30 percent), or perineal (36 vs. 22 percent) disease in these patients. At initial presentation, 88 percent of patients with pancolitis had colitis alone without other sites of intestinal disease compared with only 37 percent of patients with segmental colitis (P < 0.001). Kaplan-Meier analysis showed that patients with granulomas and patients with segmental colitis at presentation have a significantly higher recurrence when compared with patients without granulomas and patients with pancolitis (P < 0.03). Thirteen patients without granulomatous disease and eight with granuloma underwent ileal pouch-anal anastomosis. Seven patients (3 with granuloma, 4 without granuloma) had a recurrence of Crohn's disease in the ileal pouch; 2 required pouch removal and permanent diversion for fistulizing disease in the ileal pouch and 5 were successfully treated conservatively without surgery.

CONCLUSION

The presence of granulomas and segmental involvement of the colon in patients with Crohn's colitis may reflect a more virulent clinical course. Ileal pouch-anal anastomosis may be considered as an option in select patients with Crohn's colitis without small-bowel or perianal disease. Based on our data, patients with nongranulomatous pancolitis may be better candidates for sphincter-sparing surgery.

Histologic changes in defunctioned rectums in patients with inflammatory bowel disease: a clinicopathologic study of 82 patients with long-term follow-up

PURPOSE

Inflammation occurs in defunctioned rectums in patients without inflammatory bowel disease. Defunctioned rectums in patients with inflammatory bowel disease have additional histopathologic changes that can cause diagnostic confusion. The aim of this study was to ascertain whether histologic changes in defunctioned rectums had any association with original pathologic diagnosis in the colectomy specimen, duration of defunctionalization, or occurrence of Crohn's disease-like complications during follow-up.

METHODS

In this retrospective study, we reviewed the patient records and reexamined histologically the defunctioned rectums and original colectomy specimens of 84 consecutive patients encountered between 1983 and 1986.

RESULTS

All excised rectal specimens had ulcers and erosions, usually with prominent mucosal lymphoid aggregates, often with mucosal atrophy, diffuse mucin depletion, and marked mucosal architectural distortion. Transmural lymphoid aggregates were identified in 56 patients (67 percent) and were graded as moderate or marked in 35 (42 percent). Ten rectal specimens contained nonnecrotizing granulomas. The original pathologic diagnoses from the colectomy specimens were as follows: ulcerative colitis (n = 22), Crohn's disease (n = 19), indeterminate colitis (n = 41), adenocarcinoma (n = 1), and diverticular disease (n = 1). Only mild histologic changes were observed in rectal specimens from patients with diverticular disease and adenocarcinoma, and granulomas were identified more frequently in Crohn's disease patients. Otherwise, no feature in the defunctioned rectum was associated with the original diagnosis or duration of defunctionalization. Sixteen patients (19 percent) had late surgical complications suggestive of Crohn's disease (abscess, fistula, or subsequent biopsy specimen containing nonnecrotizing granulomas) after a median follow-up of 4.8 years. Five were patients categorized as having Crohn's disease with colectomy specimen, nine had indeterminate colitis, and two had ulcerative colitis. No histologic feature in the defunctioned rectum was associated with Crohn's disease-like complications.

CONCLUSIONS

Granulomas in a defunctioned rectum were associated with an original diagnosis of Crohn's disease. Transmural lymphoid aggregates were common in defunctioned rectums in patients with inflammatory bowel disease and did not indicate Crohn's disease. Other histologic changes developed independently of diagnosis and duration of defunctionalization.

Small intestinal submucosa as a bioscaffold for biliary tract regeneration

BACKGROUND

Porcine small intestinal submucosa (SIS) biograft is used as a bioscaffold for regeneration of a variety of tissues. To date, SIS has not been used as a biliary tract graft. The purpose of this study was to evaluate the feasibility of using SIS as a scaffold for bile duct tissue regeneration in a canine model.

METHODS

Fifteen, 25- to 35-kg mongrel dogs underwent midline laparotomy and exposure of the common bile duct. Nine dogs had a longitudinal choledochotomy and a 2- x 1-cm elliptical patch of 4-ply SIS placed using 6-0 polypropylene suture. Six dogs had the anterior two thirds of the bile duct resected and a 2- to 3-cm tubularized 4-ply SIS interposition graft placed. Dogs were killed at intervals ranging from 2 weeks to 5 months. Before killing, liver function tests (alkaline phosphatase [U/L] and total bilirubin [mg/dL]) were evaluated, cholangiograms were performed, and the bile duct was examined histologically.

RESULTS

Fourteen out of 15 dogs survived and were healthy at the time of killing. The one failure was a result of a bile leak in a patched animal. The SIS showed signs of incorporation with infiltration of native fibroblasts, blood vessels, and biliary mucosa within 2 weeks. Within 3 months the SIS graft was replaced with native collagen covered with a biliary epithelium. No changes occurred at 5-month follow-up. One animal with an interposition graft developed a stricture at the proximal anastomosis within 2 months. In the remaining dogs, liver enzymes were normal, and the caliber of the common bile duct remained normal.

CONCLUSIONS

SIS can be used for regeneration of bile duct tissue in a canine model. In 13 of 15 dogs SIS resulted in regeneration of canine common bile duct when used as a patch or as an interposition graft. The potential for the use of SIS as a patch for biliary stricturoplasty, or as an interposition graft for repair of complex biliary injuries is encouraging.

An unusual presentation of enterocolic lymphocytic phlebitis

Enterocolic lymphocytic phlebitis (ELP) is a recently described disease characterized by phlebitis in the wall and mesentery of the colon and small bowel. Unlike other systemic or localized vasculitic diseases that can have similar gastrointestinal manifestations, there is no involvement of the arterial system or evidence of systemic vasculitis. The lymphocytic phlebitis affects not only the grossly involved intestinal segment but also the apparently healthy bowel. The diagnosis of ELP is histologic, and other systemic vasculitis must be ruled out. Surgical resection of the bowel not only provides the diagnostic tissue but also leads to resolution of the symptoms. In the literature, ELP has most commonly been reported to present as an acute abdomen. We describe a case of ELP presenting as a large abdominal mass, without evidence of an acute abdomen. This mass was actually diffusely thickened colonic serosa, caused by extensive organizing fat necrosis and marked edema of the serosa and bowel wall.

Endoscopic ultrasound in the pre-operative staging of rectal carcinoma

Endoscopic ultrasound (EUS) was performed prospectively to stage 45 patients with rectal cancer. Patients were staged utilizing the TNM staging system. All patients subsequently underwent surgical resection with independent histopathologic staging. Depth of invasion was accurately predicted in 40 of 45 patients (89%). Presence or absence of lymph node metastasis was correctly determined in 34 of 45 patients (79%). EUS is an accurate method for local staging of rectal cancer.

Use of a microsatellite marker in predicting dysplasia in ulcerative colitis

BACKGROUND

Patients with ulcerative colitis (UC) have an increased risk of developing colorectal cancer. The current screening protocol involves an annual colonoscopy and biopsy after the patient has had the disease for 8 years. This, however, does not prevent the development of colorectal cancer.

HYPOTHESIS

A microsatellite marker for IBD1 may identify individuals who are at greater risk of developing dysplasia and therefore colorectal cancer.

DESIGN

Case-control study.

SETTING

Single surgical practice.

PATIENTS AND METHODS

DNA was extracted from peripheral leukocytes of 152 patients: 22 with UC and dysplasia; 48 with UC and no dysplasia; 24 with colorectal cancer; and 58 with noninflammatory bowel disease, nonmalignant gastrointestinal tract disease who were used as control patients. A microsatellite marker for IBD1 (D16S541) was amplified by polymerase chain reaction. Genotypes were identified using autoradiography.

RESULTS

Six alleles and 15 genotypes were identified for marker D 16S541. Genotype CC was found in 33% (8/24) of cancer patients but only 12% (7/58) of controls (chi2 = 5.5; P = .02). Thirty-two percent (7/22) of patients with dysplastic UC also had this genotype, whereas only 8% (4/ 48) of patients with nondysplastic UC had the genotype (chi2 = 4.6; P = .03; vs controls: chi2 = 3.1; P = .08).

CONCLUSIONS

This microsatellite marker for IBD1, when combined with other markers, has the potential to be used as a screening tool for colorectal cancer and dysplasia in patients with UC. Such a marker would be of particular use in improving the sensitivity and specificity of the current screening protocol for dysplasia and colorectal cancer for patients with UC.

Methylene blue-directed biopsies improve detection of intestinal metaplasia and dysplasia in Barrett's esophagus

BACKGROUND

Endoscopically applied methylene blue selectively stains specialized columnar epithelium in Barrett's esophagus.

METHODS

The diagnostic yield and cost of cancer surveillance in patients with Barrett's esophagus using methylene blue-directed biopsies (MBDB) were compared with surveillance using a "jumbo" random biopsy technique in a prospective, sequential, controlled trial. Esophagogastroduodenoscopy was performed with either MBDB or random biopsy in a randomized sequence. The proportions of various types of epithelia in each biopsy were estimated and dysplasia was graded in a blinded fashion.

RESULTS

Forty-three patients with short- (n = 8), limited- (n = 10), and long-segment (n = 25) Barrett's esophagus were studied. Using MBDB technique, the average number of biopsies obtained per patient was significantly lower and the proportion of specialized columnar epithelium in each specimen was significantly higher compared with random biopsy. Dysplasia or cancer was diagnosed in significantly more MBDB specimens (12% vs. 6%, p = 0.004). Despite fewer biopsies per patient using MBDB, dysplasia or cancer was diagnosed in significantly more patients (44% vs. 28%, p = 0.03) than by random biopsy technique. MBDB cost less and detected more cancers than random biopsy.

CONCLUSIONS

MBDB is a more accurate and cost-effective technique than random biopsy for diagnosing specialized columnar epithelium and dysplasia/cancer, particularly in long-segment Barrett's esophagus.

Laser-induced fluorescence microscopy of normal colon and dysplasia in colonic adenomas: implications for spectroscopic diagnosis

OBJECTIVES

To determine what structures fluoresce and to what extent in normal colon and colonic adenomas to fully exploit laser-induced fluorescence spectroscopy as a tool for the diagnosis of dysplasia at endoscopy.

METHODS

Unstained frozen sections of normal colon and colonic adenomas were studied by fluorescence microscopy under 351-364-nm argon ion laser excitation. Tissue fluorescence was observed and compared to morphology in serial sections stained with hematoxylin and eosin (H&E), Movat pentachrome, mucicarmine, and oil red O.

RESULTS

In normal colon, fluorescence correlated morphologically with connective tissue fibers (principally collagen) in all layers of the bowel wall and with cytoplasmic granules within eosinophils present between the crypts in the lamina propria of the mucosa. Fluorescence of absorptive cells in normal crypts was very faint, and Goblet cells did not fluoresce. However, marked fluorescence was observed in the cytoplasms of dysplastic epithelial cells in the crypts of colonic adenomas. Fewer fluorescent connective tissue fibers were present in the lamina propria of colonic adenomas resulting in decreased fluorescence intensity as compared to that of normal colon. Fluorescent eosinophil granules were present in larger numbers in adenomas as compared with normal colon.

CONCLUSION

Laser-induced fluorescence in normal colon and colonic adenomas correlates with morphology. Previous reported differences in laser-induced fluorescence emission spectra of normal colon and colonic adenomas obtained in vitro and in vivo may be due to differences in the cytoplasmic fluorescence between the dysplastic epithelium in colonic adenomas and normal colonic epithelium. Laser-induced fluorescence spectroscopy may be useful in studying other forms of epithelial dysplasia such as that which occurs in ulcerative colitis.

Endoscopic small bowel mucosal biopsy: a controlled trial evaluating forceps size and biopsy location in the diagnosis of normal and abnormal mucosal architecture

This study was designed to determine (1) whether the site of biopsy within the proximal small bowel affects the ability to assess mucosal architecture in general, or to confirm a diagnosis of celiac sprue specifically; and (2) whether endoscopic small bowel biopsy using standard forceps can obtain adequate biopsy specimens to detect or exclude mucosal abnormalities. Three-hundred fifty-two biopsy specimens were obtained prospectively from 26 patients (8 sprue, 2 nonspecific changes, 16 normal) with "jumbo" and standard forceps from jejunum, ligament of Treitz, fourth, third, and second portions of the duodenum. There was no difference in biopsy specimen quality from different locations. All celiac sprue patients had at least one good or excellent specimen from each location, thereby allowing the diagnosis to be made equally well from second, third, and fourth portions of the duodenum, as well as at the ligament of Treitz and jejunum. No false-positive diagnoses of celiac sprue were made. Finally, the standard biopsy forceps provided good or excellent specimens in all patients.

Endoscopic management of upper gastrointestinal polyps and periampullary lesions in familial adenomatous polyposis and Gardner's syndrome

Upper gastrointestinal polyps and carcinoma, especially of the periampullary area, may occur in patients with familial adenomatous polyposis. Upper gastrointestinal polyps were present in about 43% of patients in the polyposis registry of the Cleveland Clinic who underwent screening esophagogastroduodenoscopy. Approximately one-third of these polyps were neoplastic. Three distribution patterns were recognized: 1. fundic, 2. duodenal, and 3. fundic plus duodenal. Despite the occurrence of a few gastric cancers in patients with familial adenomatous polyposis, the risk of carcinoma of the major duodenal papilla and periampullary area is more significant. It is necessary to examine the duodenal papilla with a side-viewing instrument and to obtain biopsy specimens from this structure in these patients. The major duodenal papilla was abnormal in about one-half of our patients in whom this structure was specifically examined with a side-viewing endoscope. The preliminary results of a trial of endoscopic treatment of upper gastrointestinal polyps and lesions of the major duodenal papilla in patients with familial adenomatous polyposis are described.

Comparison of suction capsule and endoscopic biopsy of small bowel mucosa

Small bowel mucosal biopsy specimens were studied in 52 consecutive patients. Twenty-six patients underwent biopsy by a suction capsule and 16 patients by endoscopy using an 8-mm forceps. Additionally, 10 patients were asked to undergo biopsy by both techniques in the same morning. Material was obtained in 81% of attempts by suction and 100% by endoscopy. Tissue obtained was excellent in 58%, good in 28%, and poor in 14% of suction biopsy specimens. Corresponding grades for endoscopy were 65%, 31%, and 4%. The frequency of abnormal findings was not different by either technique. In the 10 patients who had both procedures, mean time to completion was 43 min by suction and 12 min by endoscopy. Intravenous premedication was used in endoscopy, and patient comfort was judged as excellent in 60% with endoscopy, whereas 60% judged suction biopsy as very uncomfortable. The mean fluoroscopy time of 3.9 min necessary for suction biopsy was eliminated with endoscopy. Biopsy with an 8-mm forceps through the endoscope is the preferred way to obtain tissue from the proximal small bowel.

Surveillance for colonic carcinoma in ulcerative colitis

To evaluate the efficacy of surveillance colonoscopy with biopsy for the detection of high-grade dysplasia (HGD) or colonic carcinoma in patients with chronic ulcerative colitis, we undertook a retrospective review of 248 patients who underwent 370 examinations (mean duration of disease 12 yr). High-grade dysplasia or carcinoma was found in 24 examinations in 16 patients, with a mean duration of disease of 16 yr. There were 15 patients with HGD. Nine patients had HGD alone, 6 had HGD and carcinoma, and 1 had carcinoma without HGD. The overall incidence of HGD was 6%. Dysplasia-associated lesions or mass were the most consistent indicators of carcinoma, the combination being present in four instances. Of the 7 patients with cancer, 6 were recognized by colonoscopy, and 1 patient with negative visual endoscopic findings was discovered using surveillance biopsies. The conclusions of this study are that dysplasia is a reliable histopathologic marker and correlates with the presence of cancer in chronic ulcerative colitis; the absence of dysplasia correlates with the absence of cancer. The presence of dysplasia-associated lesions or mass with HGD is the strongest indication for operation. This study supports the use of surveillance colonoscopy in managing high-risk ulcerative colitis patients.