George Triadafilopoulos

Cyclooxygenase 2 expression in Barrett's esophagus and adenocarcinoma: Ex vivo induction by bile salts and acid exposure

BACKGROUND & AIMS Barretts esophagus (BE) results from chronic, severe gastroesophageal reflux and predisposes to esophageal adenocarcinoma. Cyclooxygenase (COX)-2 is involved in chronic inflammation and epithelial cell growth. We investigated COX-2 expression in BE and esophageal adenocarcinoma to explore a potential relation between COX-2 expression and metaplasia or carcinogenesis. METHODS Endoscopic mucosal biopsy specimens of Barretts intestinal metaplasia (n = 30), Barretts dysplasia (n = 11), and esophageal adenocarcinoma (n = 5) were compared with normal esophagus (n = 46) and duodenum (n = 46) and analyzed by Western blotting and immunohistochemistry. RESULTS Immunoblots revealed constitutive expression of COX-2 in normal esophagus and duodenum. COX-2 protein expression was significantly higher in patients with Barretts metaplasia, dysplasia, and adenocarcinoma compared with normal squamous esophageal or columnar duodenal epithelia and was heterogenous in different regions of the BE surface. Immunohistochemistry revealed prominent staining in the glands of BE, dysplasia, and adenocarcinoma and faint staining in the basal layers of squamous esophagus and the surface of the duodenum. In response to pulses of acid or bile salts in an ex vivo organ culture system, COX-2 expression increased significantly in BE tissues, and this effect was attenuated by the selective COX-2 inhibitor NS-398. CONCLUSIONS The results show COX-2 expression in normal esophagus, which increases significantly in BE and esophageal adenocarcinoma. COX-2 is regulated ex vivo by exposure to acid or bile salts.

Molecular Evolution of the Metaplasia-Dysplasia-Adenocarcinoma Sequence in the Esophagus

The incidence of adenocarcinoma of the esophagus has been increasing in developing countries over the last three decades and probably reflects a genuine increase in the incidence of its recognized precursor lesion, Barretts metaplasia. Despite advances in multimodality therapy, the prognosis for invasive esophageal adenocarcinoma is poor. An improved understanding of the molecular biology of this disease may allow improved diagnosis, therapy, and prognosis. We focus on recent developments in the molecular and cell biology of Barretts metaplasia, a heterogeneous lesion affecting the transitional zone of the gastro-esophageal junction whose associated molecular alterations may vary both in nature and temporally. Early premalignant clones produce biological and genetic heterogeneity as seen by multiple p53 mutations, p16 mutations, aneuploidy, and abnormal methylation resulting in stepwise changes in differentiation, proliferation, and apoptosis, allowing disease progression under selective pressure. Abnormalities in expression of growth factors of the epidermal growth factor family and cell adhesion molecules, especially cadherin/catenin complexes, may occur early in invasion. Exploitation of these molecular events may lead to a more appropriate diagnosis and understanding of these lesions in the future.

Dynamic effects of acid on Barrett's esophagus. An ex vivo proliferation and differentiation model.

Barretts esophagus (BE), or specialized intestinal metaplasia, is a premalignant heterogeneous epithelium associated with reflux and an increased risk for adenocarcinoma. Since acid is a major component of refluxate, we investigated its effects ex vivo on cell differentiation as determined by villin expression; and on cell proliferation, as determined by tritiated thymidine incorporation and proliferating cell nuclear antigen expression. To mimic known physiological conditions, endoscopic biopsies of normal esophagus, BE, and duodenum were exposed, in organ culture, to acidified media (pH 3-5) either continuously, or as a 1-h pulse and compared with exposure to pH 7.4 for up to 24 h. Before culture, villin expression was noted in 25% of BE samples, and increased after 6 or 24 h of continuous acid to 50% or 83% of BE samples, respectively. Increased villin expression correlated with ultrastructural maturation of the brush border. In contrast, an acid-pulse followed by culture at pH 7.4, did not alter villin expression in BE. Moreover, continuous acid exposure blocked cell proliferation in BE, whereas, an acid-pulse enhanced cell proliferation, as compared to pH 7.4. Based on our ex vivo findings, we propose a model in which the diverse patterns of acid exposure in vivo may contribute to the observed heterogeneity and unpredictable progression to neoplasia of BE.

Duodenal and Gastric Ulcer Prevention with Misoprostol in Arthritis Patients Taking NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) remain the agents of choice in the treatment of many rheumatic diseases because of their analgesic and anti-inflammatory properties. However, use of NSAIDs is also associated with an increased frequency of peptic ulcers and ulcer complications, such as major upper gastrointestinal bleeding and perforation [1-8]. It has been estimated that in the United States, NSAID-induced gastrointestinal complications account for at least 2600 deaths and 20 000 hospitalizations each year in rheumatoid arthritis patients alone [9]. The concern about NSAID-induced gastroduodenal damage is heightened because complications often occur without preceding symptoms of ulcer disease [10, 11]. The prevalence of endoscopically confirmed upper gastrointestinal ulcers in NSAID users has been reported to range between 15% and 31% [12-17]. Despite the predominance of gastric ulcers in chronic NSAID users, ulcer complications in NSAID users are often associated with duodenal ulcers [7, 11, 18-20]. Duodenal ulcers are more common than gastric ulcers in patients not taking NSAIDs, suggesting that many duodenal ulcers associated with NSAID use may reflect NSAID exacerbation of preexisting peptic ulcer disease [21, 22]. Misoprostol, a synthetic prostaglandin E1 analog, has been shown to be effective in decreasing the incidence of gastric ulcers in chronic NSAID users [17, 23] without interfering with the antirheumatic effects of the NSAID. The H2-receptor antagonist, ranitidine, and the topical agent, sucralfate, have not been effective in preventing gastric ulcers in long-term NSAID users [23-25]. Ranitidine-NSAID cotherapy decreased the frequency of duodenal ulcers in NSAID-treated patients, suggesting that duodenal ulcers in NSAID users may have a different pathogenesis than gastric ulcers [24, 25]. Our study was designed to investigate the efficacy of misoprostol for the prevention of NSAID-induced duodenal ulcers in arthritis patients receiving long-term NSAID therapy. Methods Patients were recruited from private practice offices, Veterans Affairs clinics, health maintenance organizations, and academic institutions. The study was done between June 1989 and February 1991. Patients were eligible to enter the study if they had rheumatoid arthritis, osteoarthritis, psoriatic arthritis, ankylosing spondylitis, or the Reiter syndrome. Upper gastrointestinal pain was not required for entry into the study, but patients were expected to require at least 3 additional months of daily NSAID therapy with either ibuprofen, piroxicam, naproxen, sulindac, tolmetin, indomethacin, or diclofenac. Women were required to be postmenopausal, surgically sterilized, or practicing adequate contraception. Other exclusion criteria were a history of peptic ulcer disease requiring treatment in the 30 days immediately before entry, upper gastrointestinal malignancy, pyloric obstruction, acute hepatitis, pancreatitis, bleeding diathesis, upper gastrointestinal surgery within 30 days, or severe renal impairment. In addition, patients taking antineoplastic drugs, anticoagulants, anti-ulcer drugs other than the study drug, or prednisone at dosages of more than 7.5 mg/d were excluded. Study Design The study was a randomized, double-blind, placebo-controlled, multicenter trial of misoprostol, 200 g given four times a day (with meals and at bedtime with food). Upper gastrointestinal symptoms were scored using a 0 to 3 grading scale; zero corresponded to no abdominal pain, 1 corresponded to mild pain, 2 corresponded to moderate pain, and 3 corresponded to severe abdominal pain. Patients with gastric or duodenal ulcers of any size as well as those with erosions 0.3 cm in diameter at baseline upper gastrointestinal endoscopy were excluded. Patients who were accepted were randomized (randomization was balanced within each center) and received misoprostol or placebo within 72 hours of the entry endoscopic examination. Patients continued to take NSAIDs at the same dosage administered before the study. Patients were allowed to take up to three aluminum hydroxide antacid tablets (Amphojel [600 mg], Wyeth-Ayerst Laboratories, Philadelphia, Pennsylvania) per day for the first 2 weeks of the study for relief of upper gastrointestinal pain. After 4 weeks ( 3 days), 8 weeks ( 5 days), and 12 weeks ( 5 days) of treatment with misoprostol or placebo, endoscopic examinations and upper gastrointestinal pain evaluations were repeated. Endoscopists remained blinded to the patients medication. Patients were instructed to take the study medication the night before the endoscopy and not to take the next dose until after the procedure was completed. Noncompliance was defined as failure to take at least 60% of prescribed medication during the study period, determined by pill count at 4, 8, and 12 weeks of therapy. The protocol was approved by an institutional review board, and each patient gave written, informed consent. Data Analysis Any patient who received at least one dose of study medication qualified for analysis of the frequency of adverse experiences. The primary analysis for efficacy was of the intention-to-treat group. In addition, any patient who took at least 60% of the doses of study medication during the time of study participation, who had not missed more than 3 consecutive days of study medication, who satisfied the inclusion or exclusion criteria, and who had an initial and final endoscopic examination was considered evaluable for efficacy. Figure 1. Percentage of evaluable and intent-to-treat patients with duodenal ulcers. P P The primary end point of the study was the development of a duodenal ulcer at follow-up endoscopic examination. An ulcer was defined as a circumscribed break in the duodenal or gastric mucosa of 0.5 cm in diameter (0.5 cm by 0.5 cm or larger) and with perceptible depth. The comparability of the misoprostol and placebo treatment groups with respect to demographic characteristics at admission was assessed for all patients enrolled in the study. These characteristics included age, sex, race, height, and weight. When expected cell sizes were adequate, nominal measures were compared using the Pearson chi-square test. Otherwise, the Fisher exact test was used. Height, weight, and age measures were compared in the two treatment groups using the Wilcoxon rank-sum test. Treatment group differences in the proportion of patients who completed the study and the proportion of evaluable patients were assessed using the Pearson chi-square test. Patients who discontinued study participation without an endoscopy at week 4, week 8, or week 12 were classified as unknown for each time period at which their endoscopy status was undetermined. A chi-square analysis of duodenal ulcer development during the 12-week period was then conducted. Secondary analyses using identical methods were done for gastric ulcer development and gastroduodenal ulcer development. The rates of developing ulcers presented above did not account for censoring (that is, patients who discontinued the study before endoscopic verification of outcome or before they finished the full 12 weeks of study participation). Therefore, rates of developing duodenal, gastric, and gastroduodenal ulcer were also compared in the two treatment groups using a life-table analysis, which provided actuarial method estimates of the rate of ulcer development. The grouping intervals used for the life-table were prestudy to week-4 endoscopy, week-4 to week-8 endoscopy, and week-8 to week-12 endoscopy. The actual number of days from the prestudy endoscopy to the week 4, week 8, and week 12 endoscopies was not used to construct the life-table intervals; consequently, they can only be considered nominal categories. The log-rank test was used to compare the survival distributions of the two treatment groups. Figure 2. Percentage of intention-to-treat patients developing ulcers during the 12-week study period. Additional analyses using a stepwise logistic regression model were done to assess the effect of selected demographic and medical history measures on ulceration. Age, sex, alcohol consumption, smoking, type of arthritis, baseline erosions, and treatment group were the independent variables for these models. A forward selection procedure was used, with step selection of variables based on the maximum likelihood ratio and resulting P values from the chi-square statistics. A variable entered the model if its P value for entry was less than 0.15 and was retained in the model if its P value for removal was 0.15. Treatment group was initially entered in each model before beginning the stepping process. For these analyses, type of arthritis was categorized as osteoarthritis versus rheumatoid arthritis; patients who had both osteoarthritis and ankylosing spondylitis, or both osteoarthritis and psoriatic arthritis, were categorized as having osteoarthritis. Patients who had the other types of arthritis (including both osteoarthritis and rheumatoid arthritis) were excluded from the logistic regression analyses. The qualitative investigator assessments (daytime and nighttime pain and upper gastrointestinal symptoms) were tabulated at each visit by treatment group for evaluable patients. The distributions of the investigators severity ratings for daytime and nighttime pain were each compared for the two treatment groups at 12 weeks using the Fisher exact test. For patients who reported daytime or nighttime pain at the prestudy visit, changes from prestudy to week 12 in daytime and nighttime pain were categorized as better, same, or worse and compared in the two treatment groups using the Pearson chi-square test or the Fisher exact test, depending on the distribution of responses. For patients who did not report daytime or nighttime pain at the prestudy visit, the proportion of patients who developed daytime or nighttime pain at week 12 was compared in the two treatment groups using the Pearson chi

Circumferential ablation of Barrett's esophagus that contains high-grade dysplasia: a U.S. multicenter registry

BACKGROUND The management strategies for Barretts esophagus (BE) that contains high-grade dysplasia (HGD) include intensive endoscopic surveillance, photodynamic therapy, thermal ablation, EMR, and esophagectomy. OBJECTIVE To assess the safety and effectiveness of endoscopic circumferential balloon-based ablation by using radiofrequency energy for treating BE HGD. DESIGN Multicenter U.S. registry. SETTING Sixteen academic and community centers; treatment period from September 2004 to March 2007. PATIENTS Patients with histologic evidence of intestinal metaplasia (IM) that contained HGD confirmed by at least 2 expert pathologists. A prior EMR was permitted, provided that residual HGD remained in the BE region for ablation. INTERVENTION Endoscopic circumferential ablation with follow-up esophageal biopsies to assess the histologic response to treatment. OUTCOMES Histologic complete response (CR) end points: (1) all biopsy specimen fragments obtained at the last biopsy session were negative for HGD (CR-HGD), (2) all biopsy specimens were negative for any dysplasia (CR-D), and (3) all biopsy specimens were negative for IM (CR-IM). RESULTS A total of 142 patients (median age 66 years, interquartile range [IQR] 59-75 years) who had BE HGD (median length 6 cm, IQR 3-8 cm) underwent circumferential ablation (median 1 session, IQR 1-2). No serious adverse events were reported. There was 1 asymptomatic stricture and no buried glands. Ninety-two patients had at least 1 follow-up biopsy session (median follow-up 12 months, IQR 8-15 months). A CR-HGD was achieved in 90.2% of patients, CR-D in 80.4%, and CR-IM in 54.3%. LIMITATIONS A nonrandomized study design, without a control arm, a lack of centralized pathology review, ablation and biopsy technique not standardized, and a relatively short-term follow-up. CONCLUSIONS Endoscopic circumferential ablation is a promising modality for the treatment of BE that contains HGD. In this multicenter registry, the intervention safely achieved a CR for HGD in 90.2% of patients at a median of 12 months of follow-up.

Adverse effects of long-term proton pump inhibitor therapy.

Proton pump inhibitors have an excellent safety profile and have become one of the most commonly prescribed class of drugs in primary and specialty care. Long-term, sometimes lifetime, use is becoming increasingly common, often without appropriate indications. This paper is a detailed review of the current evidence on this important topic, focusing on the potential adverse effects of long-term proton pump inhibitor use that have generated the greatest concern: B12 deficiency; iron deficiency; hypomagnesemia; increased susceptibility to pneumonia, enteric infections, and fractures; hypergastrinemia and cancer; drug interactions; and birth defects. We explain the pathophysiological mechanisms that may underlie each of these relationships, review the existing evidence, and discuss implications for clinical management. The benefits of proton pump inhibitor use outweigh its risks in most patients. Elderly, malnourished, immune-compromised, chronically ill, and osteoporotic patients theoretically could be at increased risk from long-term therapy.

Complete elimination of reflux symptoms does not guarantee normalization of intraesophageal acid reflux in patients with Barrett's esophagus

Objective:Normalization of intraesophageal acid exposure is increasingly recognized as a desired goal in the management of Barretts esophagus. In this prospective trial, we studied patients with Barretts esophagus by 24-h intraesophageal pH monitoring after having completely eliminated their reflux symptoms with lansoprazole, to determine whether they had achieved normalization of intraesophageal pH.Methods:Thirty patients with Barretts esophagus, all of whom had presented with reflux symptoms, were treated with lansoprazole (15–30 mg/day) until they were asymptomatic. Twenty-four-hour ambulatory pH monitoring was performed while they were receiving lansoprazole and were asymptomatic.Results:Twelve patients (40%) showed persistent bipositional, pathologic acid reflux while on therapy, with a mean DeMeester score of 52.8 (95% CI: 33.8–71.8); the remaining 18 (60%) exhibited normalization of intraesophageal acid exposure with a score of 4.4 (95% CI: 2.3–6.6, p < 0.001). This inadequate control of intraesophageal pH is most likely due to incomplete gastric acid suppression induced by the drug and is associated with a variable acid (distal > proximal) exposure within the esophagus. The two groups were not different in regard to their symptom frequency and severity before therapy, amount of lansoprazole dosage required to eliminate symptoms, length of Barretts metaplasia, presence of hiatal hernia, lower esophageal sphincter resting tone and length, or esophageal peristaltic function.Conclusions:Complete symptom eradication with lansoprazole (15–30 mg daily) in patients with Barretts esophagus does not guarantee normalization of intraesophageal pH profile. If the goal of therapy in such patients is to achieve complete intraesophageal acid suppression, 24-h ambulatory esophageal pH monitoring should be performed to titrate therapy.

Risk of perforation from a colonoscopy in adults: a large population-based study.

BACKGROUND Previous studies that reported the incidence of perforation from a colonoscopy are limited by small sample sizes, restricted age groups, or single-center data. OBJECTIVE To determine the incidence and risk factors of colonic perforation from a colonoscopy in a large population cohort. DESIGN Retrospective, population-based, cohort study, followed by a nested case-control study. SETTING California Medicaid program claims database. PATIENTS A total of 277,434 patients (aged 18 years and older) who underwent a colonoscopy during 1995 to 2005, age, sex, and time matched to 4 unique general-population controls. MAIN OUTCOME MEASUREMENTS Perforation incidence in the 7 days after colonoscopy (or matched index date for controls) with odds ratio (OR); multivariate logistic regression to calculate adjusted ORs for subsequent analysis of risk factors. RESULTS A total of 228 perforations were diagnosed after 277,434 colonoscopies, which corresponded to a cumulative 7-day incidence of 0.082%. The OR of getting a perforation from a colonoscopy compared with matched controls (n = 1,072,723) who did not undergo a colonoscopy was 27.6 (95% CI, 19.04-39.92), P < .001. On multivariate analysis, when comparing the group that had a perforation after a colonoscopy (n = 216) with those who did not (n = 269,496), increasing age, significant comorbidity, obstruction as an indication for the colonoscopy, and performance of invasive interventions during colonoscopy were significant positive predictors. Performance of biopsy or polypectomy did not affect the perforation risk. The rate of perforation did not change significantly over time. LIMITATIONS Validity of coding and capturing of all perforation diagnoses may possibly be deficient. CONCLUSION The risk of perforation from a colonoscopy is low, but, despite increased experience with the procedure, it remains unchanged over time.

Antimicrobial resistance incidence and risk factors among Helicobacter pylori-infected persons, United States.

Helicobacter pylori is the primary cause of peptic ulcer disease and an etiologic agent in the development of gastric cancer. H. pylori infection is curable with regimens of multiple antimicrobial agents, and antimicrobial resistance is a leading cause of treatment failure. The Helicobacter pylori Antimicrobial Resistance Monitoring Program (HARP) is a prospective, multicenter U.S. network that tracks national incidence rates of H. pylori antimicrobial resistance. Of 347 clinical H. pylori isolates collected from December 1998 through 2002, 101 (29.1%) were resistant to one antimicrobial agent, and 17 (5%) were resistant to two or more antimicrobial agents. Eighty-seven (25.1%) isolates were resistant to metronidazole, 45 (12.9%) to clarithromycin, and 3 (0.9%) to amoxicillin. On multivariate analysis, black race was the only significant risk factor (p < 0.01, hazard ratio 2.04) for infection with a resistant H. pylori strain. Formulating pretreatment screening strategies or providing alternative therapeutic regimens for high-risk populations may be important for future clinical practice.

Use of a simple symptom questionnaire to predict Barrett's esophagus in patients with symptoms of gastroesophageal reflux

OBJECTIVE:Accurately predicting Barretts esophagus (BE) in patients with gastroesophageal reflux disease (GERD) is difficult. Using logistic regression analysis of symptom questionnaire scores we created a model to predict the presence of BE.METHODS:We conducted a logistic regression analysis of symptom data collected prospectively on 517 GERD patients and created a prediction model based on patient gender, age, ethnicity, and symptom severity.RESULTS:There were 337 (65%) males and 180 (35%) females, of whom 99 (19%) had Barretts esophagus (BE). Multiple logistic regression analysis was performed to determine the predictive ability of gender, age, and ethnicity along with symptoms of heartburn, nocturnal pain, odynophagia, presence of belching, dysphagia, relief of symptoms with food, and nausea. The only significant predictors (at the 0.05 level) were male gender, heartburn, nocturnal pain, and odynophagia (all with positive effects on the presence of BE) and dysphagia (which had a negative effect). A nomogram was produced to show the effect of a given predictor on the probability of having BE in the context of the effects of the other predictors, and to estimate the probability of having BE for a given individual. The mean score (±SD) for the BE patients in our sample was 397.4 ± 46.2 with a range of 292–530. For the patients without BE, the mean score (±SD) was 351.3 ± 60.3 with a range of 190 – 528 (p < 0.001). If screening for BE is performed at a score of 375 or more, our model would have a specificity of 63% with a sensitivity of 77% (95% CI 61–86% given the 63% specificity).CONCLUSIONS:By asking seven questions about symptom severity, clinicians may be able to assign a probability to the presence of BE, and thus, determine the need for endoscopy in GERD patients.