Julia J. Liu

Increased epithelial gaps in the small intestines of patients with inflammatory bowel disease: density matters

BACKGROUND Epithelial gaps created by shedding of epithelial cells in the small intestine can be visualized by using confocal laser endomicroscopy (CLE). The density of epithelial gaps in the small bowels of patients with inflammatory bowel disease (IBD) and controls without IBD is unknown. OBJECTIVE To determine whether the epithelial gap density in patients with IBD is different from that in controls. DESIGN Prospective, controlled, cohort study. SETTING A tertiary-care referral center. PATIENTS This study involved patients with IBD and control patients without IBD undergoing colonoscopy. INTERVENTION Probe-based CLE (pCLE) was used to image the terminal ileum. MAIN OUTCOME MEASUREMENTS The primary outcome of the study was gap density, defined as the total number of gaps per 1000 cells counted in adequately imaged villi by using pCLE. The pCLE images were blindly reviewed, and the number of epithelial gaps and cells were manually counted. The secondary outcomes were correlation of gap density with disease activity, location, and severity of clinical disease. RESULTS There were 30 controls and 28 patients with IBD. Of the patients with IBD, 16 had Crohns disease, and 12 had ulcerative colitis. The median epithelial gap densities for controls and patients with IBD were 18 and 61 gaps/1000 cells, respectively (P < .001). Gap density did not correlate with disease activity. Patients with ulcerative pan-colitis tended toward gap densities lower than those of patients with limited colitis (32 versus 97 gaps/1000 cells, P = .06). Patients with IBD with severe clinical disease also had lower median gap densities (37 vs 90 gaps/1000 cells, P = .04). LIMITATIONS A single-center study. CONCLUSION The epithelial gap density was significantly increased in patients with IBD compared with controls. ( CLINICAL TRIAL REGISTRATION NUMBER NCT00988273.).

Mind the gaps: confocal endomicroscopy showed increased density of small bowel epithelial gaps in inflammatory bowel disease.

Objectives Confocal endomicroscopy can be used to image intestinal mucosa. Epithelial gaps resulting from shedding of epithelial cells have been reported in patients. We hypothesize that the rate of epithelial cell shedding increases in patients with Crohns disease, leading to more epithelial gaps and barrier dysfunction. In this study, we used probe-based confocal laser endomicroscopy to quantify epithelial cells and gaps in patients with Crohns disease compared with controls. We also determined the density of epithelial gaps in a mouse model of inflammatory bowel disease—interleukin-10-deficient (IL-10−/−) mice, versus the background strain using rigid probe confocal endomicroscopy. Methods Probe-based confocal laser endomicroscopy of the terminal ileum of both patients with Crohns disease and controls was performed by a single endoscopist during colonoscopy. In mice, sections of the small intestine were imaged using a rigid confocal probe. Gap density was defined as the number of epithelial gaps per 1000 cells counted. Results In this study, we examined 6 controls (2 male and 4 female; median age 59 y) and 8 patients with Crohns disease (5 male and 3 female; median age 42 y). The mean gap densities (±standard error) observed for the 2 groups were 17.7±5.6 and 117±33 gaps per 1000 cells, respectively (P<0.01). For control and IL-10−/− mice, the gap densities were 10.5±2.2 and 17.8±1.4 gaps per 1000 cells, respectively (P<0.01). Conclusions The epithelial gap density was significantly higher in patients with Crohns disease than controls. Gap density was also elevated in the mouse model of inflammatory bowel disease.

Increased Epithelial Gaps in the Small Intestine Are Predictive of Hospitalization and Surgery in Patients With Inflammatory Bowel Disease

OBJECTIVES:Epithelial gaps resulting from intestinal cell extrusions can be visualized with confocal laser endomicroscopy (CLE) during colonoscopy and increased in normal-appearing terminal ileum of inflammatory bowel disease (IBD) patients. Cell-shedding events on CLE were found to be predictive of disease relapse. The aim of this study was to assess the prognostic value of epithelial gap densities for major clinical events (hospitalization or surgery) in follow-up.METHODS:We prospectively followed IBD patients undergoing colonoscopy with probe-based CLE (pCLE) for clinical events including symptom flares, medication changes, hospitalization, or surgery. Survival analysis methods were used to compare event times for the composite outcome of hospitalization or surgery using log-rank tests and Cox proportional hazards models. We also examined the relationship of gap density with IBD flares, need for anti-tumor necrosis factor therapy, disease duration, gender and endoscopic disease severity, and location.RESULTS:A total of 21 Crohns disease and 20 ulcerative colitis patients with a median follow-up of 14 (11–31) months were studied. Patients with elevated gap density were at significantly higher risk for hospitalization or surgery (log-rank test P=0.02). Gap density was a significant predictor for risk of major events, with a hazard ratio of 1.10 (95% confidence interval=1.01, 1.20) associated with each increase of 1% in gap density. Gap density was also correlated with IBD disease duration (Spearmans correlation coefficient rho=0.44, P=0.004), and was higher in male patients (9.0 vs. 3.6 gaps per 100 cells, P=0.038).CONCLUSIONS:Increased epithelial gaps in the small intestine as determined by pCLE are a predictor for future hospitalization or surgery in IBD patients.

Gastroesophageal junction smooth muscle remodeling after endoluminal gastroplication.

OBJECTIVES:Endoluminal gastroplication (ELGP) is an endoscopic mucosal suturing procedure for the treatment of gastroesophageal reflux disease. The antireflux mechanism of the mucosal suture remains poorly understood. The aim of this study is to investigate any morphologic changes in the smooth muscle layer induced by the mucosal sutures placed at the gastroesophageal junction.METHODS:ELGPs were performed using endoscopic suturing devices with placement of two or three circumferential sutures within 2 cm of the squamocolumnar junction. Eight patients with subsequent symptom resolution underwent endoscopic ultrasound (EUS) to evaluate the muscularis propria layer at the gastroesophageal junction. A swine model was used for EUS and histopathologic correlation study. Six control and 15 ELGP pigs were evaluated with EUS and histological examination of the gastroesophageal junction smooth muscle layer.RESULTS:Focal thickening of the muscularis propria layer near the suture region (2.3 ± 0.4 mm vs 1.4 ± 0.3 mm, p < 0.01) was found in eight patients with symptomatic resolution. In ELGP pigs, the smooth muscle layer thickness increased by 2.6 mm near the suture site by EUS. By histology, the total and circular smooth muscle layer thickness increased by 2.1 mm and 1.9 mm, respectively.CONCLUSIONS:Focal thickening of smooth muscle layer occurs at the gastroesophageal junction after ELGP in patients with gastroesophageal reflux disease. This finding was reproduced in a swine model and localized hypertrophy was found to be entirely due to an increase in the circular smooth muscle layer.

Breaks in the wall: increased gaps in the intestinal epithelium of irritable bowel syndrome patients identified by confocal laser endomicroscopy (with videos).

BACKGROUND Altered intestinal permeability and mucosal inflammation have been reported in irritable bowel syndrome (IBS) patients. Increased cell extrusion in the epithelium as measured by epithelial gaps may be associated with barrier dysfunction and may lead to mucosal inflammation. Confocal laser endomicroscopy can be used to identify and quantitate epithelial gaps in the small intestine. OBJECTIVE To determine the epithelial gap density in IBS and healthy control patients. DESIGN Prospective, controlled cohort study. SETTING A tertiary referral center. PATIENTS In IBS and control patients undergoing routine colonoscopy, probe-based confocal laser endomicroscopy was used to image the terminal ileum. MAIN OUTCOME MEASUREMENTS The primary outcome was the density of epithelial gaps (gaps/cells counted) in adequately imaged villi using pCLE. Images were reviewed by 2 blinded reviewers. RESULTS We recruited 18 healthy controls and 16 IBS patients. The median epithelial gap densities for control and IBS patients were 6 and 32 gaps per 1000 cells, respectively (P < .001). There was a trend toward higher gap density in female (P = .07) and younger (ρ = -0.43, P = .07) patients. Using 3% (90% of the control population) as the cutoff for abnormal gap density, we found the diagnostic accuracy for IBS to be as follows: 62% sensitivity, 89% specificity, 83% positive predictive value, and 73% negative predictive value. LIMITATIONS A single-center study, small number of patients. CONCLUSIONS IBS patients have significantly more epithelial gaps in their small intestine compared with healthy controls, which suggests that increased epithelial cell extrusion may be a cause of altered intestinal permeability observed in IBS.

A balanced IL-1β activity is required for host response to Citrobacter rodentium infection.

Microbial sensing plays essential roles in the innate immune response to pathogens. In particular, NLRP3 forms a multiprotein inflammasome complex responsible for the maturation of interleukin (IL)-1β. Our aim was to delineate the role of the NLRP3 inflammasome in macrophages, and the contribution of IL-1β to the host defense against Citrobacter rodentium acute infection in mice. Nlrp3−/− and background C57BL/6 (WT) mice were infected by orogastric gavage, received IL-1β (0.5 µg/mouse; ip) on 0, 2, and 4 days post-infection (DPI), and assessed on 6 and 10 DPI. Infected Nlrp3−/− mice developed severe colitis; IL-1β treatments reduced colonization, abrogated dissemination of bacteria to mesenteric lymph nodes, and protected epithelial integrity of infected Nlrp3−/− mice. In contrast, IL-1β treatments of WT mice had an opposite effect with increased penetration of bacteria and barrier disruption. Microscopy showed reduced damage in Nlrp3−/− mice, and increased severity of disease in WT mice with IL-1β treatments, in particular on 10 DPI. Secretion of some pro-inflammatory plasma cytokines was dissipated in Nlrp3−/− compared to WT mice. IL-1β treatments elevated macrophage infiltration into infected crypts in Nlrp3−/− mice, suggesting that IL-1β may improve macrophage function, as exogenous administration of IL-1β increased phagocytosis of C. rodentium by peritoneal Nlrp3−/− macrophages in vitro. As well, the exogenous administration of IL-1β to WT peritoneal macrophages damaged the epithelial barrier of C. rodentium-infected polarized CMT-93 cells. Treatment of Nlrp3−/− mice with IL-1β seems to confer protection against C. rodentium infection by reducing colonization, protecting epithelial integrity, and improving macrophage activity, while extraneous IL-1β appeared to be detrimental to WT mice. Together, these findings highlight the importance of balanced cytokine responses as IL-1β improved bacterial clearance in Nlrp3−/− mice but increased tissue damage when given to WT mice.

Epithelial cell extrusion leads to breaches in the intestinal epithelium.

Background:Two distinct forms of intestinal epithelial cell (IEC) extrusion are described: 1 with preserved epithelial integrity and 1 that introduced breaches in the epithelial lining. In this study, we sought to determine the mechanism underlying the IEC extrusion that alters the permeability of the gut epithelium. Methods:IEC extrusions in polarized T84 monolayer were induced with nigericin. Epithelial permeability was assessed with transepithelial electrical resistance and movements of latex microspheres and green fluorescent protein–transfected Escherichia coli across the monolayer. In vivo IEC extrusion was modulated in wild-type and a colitic (interleukin-10 knock-out) mouse model with caspase-1 activation and inhibition. Luminal aspirates and mucosal biopsies from control patients and patients with inflammatory bowel disease were analyzed for caspase-1 and caspase-3&7 activation. Results:Caspase-1–induced IEC extrusion in T84 monolayers resulted in dose-dependent and time-dependent barrier dysfunction, reversible with caspase-1 inhibition. Moreover, the movements of microspheres and microbes across the treated epithelial monolayers were observed. Increased caspase-1–mediated IEC extrusion in interleukin-10 knock-out mice corresponded to enhanced permeation of dextran, microspheres, and translocation of E. coli compared with wild type. Caspase-1 inhibition in interleukin-10 knock-out mice resulted in a time-dependent reduction in cell extrusion and normalization of permeability to microspheres. Increased IEC extrusion in wild-type mice was induced with caspase-1 activation. In human luminal aspirates, the ratio of positively stained caspase-1 to caspase-3&7 cells were 1:1 and 2:1 in control patients and patients with inflammatory bowel disease, respectively; these observations were confirmed by cytochemical analysis of mucosal biopsies. Conclusions:IEC extrusion mediated by caspase-1 activation contributes to altered intestinal permeability in vitro and in vivo.

Endoscopic Treatment for Atypical Manifestations of Gastroesophageal Reflux Disease

OBJECTIVES:Atypical manifestations are common in patients with gastroesophageal reflux disease (GERD). The aim of this study was to evaluate the response of atypical manifestations of GERD to endoscopic antireflux treatment.METHODS:Patients with atypical manifestations of GERD including hoarseness, cough, wheezing, and non-cardiac chest pain were studied. Endoscopic antireflux treatment consisted of placement of sutures below the squamo-columnar junction. Clinical response was defined as complete resolution of the atypical symptom. Patients were followed clinically for up to 3 yr after the procedure. Short-term response was evaluated within 6 months of the procedure, and long-term follow-up was determined 1–3 yr after the procedure.RESULTS:Forty-three patients met the inclusion criteria; four patients underwent repeat procedures during the study period and were excluded from the analysis. Long-term follow-up was available in all 39 patients. Short-term response counts were: hoarseness, 12 of 19 patients, cough, 17 of 19; wheezing, 8 of 9; and chest pain, 13 of 18. Long-term follow-up of patients (mean of 18 months) for these symptoms was not significantly different compared to short-term response.CONCLUSIONS:Endoscopic suturing of the gastroesophageal junction appears to be a possible treatment option for atypical manifestations of GERD and future studies are needed to determine its role in management.

Endoscopic pH monitoring for patients with suspected or refractory gastroesophageal reflux disease

BACKGROUND Wireless pH studies can offer prolonged pH monitoring, which may potentially facilitate the diagnosis and management of patients with gastroesophageal reflux disease (GERD). The aim of the present study was to evaluate the detection rate of abnormal esophageal acid exposure using prolonged pH monitoring in patients with suspected or refractory GERD symptoms. METHODS Patients undergoing prolonged ambulatory pH studies for the evaluation of GERD-related symptoms were assessed. Patients with a known diagnosis of GERD were tested on medical therapy, while patients with suspected GERD were tested off therapy. The wireless pH capsules were placed during upper endoscopy 6 cm above the squamocolumnar junction. RESULTS One hundred ninety-one patients underwent a total of 198 pH studies. Fifty ambulatory pH studies (25%) were excluded from the analysis: 27 patients (14%) had insufficient data capture (less than 18 h on at least one day of monitoring), 15 patients had premature capsule release (7%), seven were repeat studies (3.5%) and one had intolerable pain requiring capsule removal (0.5%). There were 115 patients undergoing pH studies who were off medication, and 33 patients were on therapy. For the two groups of patients, results were as follows: 32 (28%) and 22 (67%) patients with normal studies on both days; 58 (50%) and five (15%) patients with abnormal studies on both days; 18 (16%) and three (9%) patients with abnormal studies on day 1 only; and seven (6%) and three (9%) patients with abnormal studies on day 2 only, respectively. CONCLUSIONS Prolonged 48 h pH monitoring can detect more abnormal esophageal acid exposure but is associated with a significant rate of incomplete studies.

Refractory gastro-oesophageal reflux disease: diagnosis and management.

Refractory gastro-oesophageal reflux disease (GORD) is described when reflux symptoms have not responded to 4–8 weeks of proton pump inhibitor therapy and occurs in a heterogeneous mixture of patients. The causes of refractory GORD include inadequate acid suppression, non-acid gastro-oesophageal reflux, and non-reflux causes of GORD symptoms including achalasia, gastroparesis and functional heartburn. Upper gastrointestinal tract endoscopy should initially be performed to identify the presence of oesophagitis, and exclude other diagnoses including eosinophilic oesophagitis and peptic ulcer disease. Patients with refractory symptoms but with a normal upper endoscopy are more difficult to diagnose and may require ambulatory pH monitoring, impedance testing, oesophageal motility tests and gastric emptying scans. The primary goal of treatment is symptom reduction and eventual elimination, which can be achieved with proper identification of the underlying cause of the symptoms.