Wai K. Leung

Preventing recurrent upper gastrointestinal bleeding in patients with Helicobacter pylori infection who are taking low-dose aspirin or naproxen

BACKGROUND Many patients who have had upper gastrointestinal bleeding continue to take low-dose aspirin for cardiovascular prophylaxis or other non-steroidal antiinflammatory drugs (NSAIDs) for musculoskeletal pain. It is uncertain whether infection with Helicobacter pylori is a risk factor for bleeding in such patients. METHODS We studied patients with a history of upper gastrointestinal bleeding who were infected with H. pylori and who were taking low-dose aspirin or other NSAIDs. We evaluated whether eradication of the infection or omeprazole treatment was more effective in preventing recurrent bleeding. We recruited patients who presented with upper gastrointestinal bleeding that was confirmed by endoscopy. Their ulcers were healed by daily treatment with 20 mg of omeprazole for eight weeks or longer. Then, those who had been taking aspirin were given 80 mg of aspirin daily, and those who had been taking other NSAIDs were given 500 mg of naproxen twice daily for six months. The patients in each group were then randomly assigned separately to receive 20 mg of omeprazole daily for six months or one week of eradication therapy, consisting of 120 mg of bismuth subcitrate, 500 mg of tetracycline, and 400 mg of metronidazole, all given four times daily, followed by placebo for six months. RESULTS We enrolled 400 patients (250 of whom were taking aspirin and 150 of whom were taking other NSAIDs). Among those taking aspirin, the probability of recurrent bleeding during the six-month period was 1.9 percent for patients who received eradication therapy and 0.9 percent for patients who received omeprazole (absolute difference, 1.0 percent; 95 percent confidence interval for the difference, -1.9 to 3.9 percent). Among users of other NSAIDs, the probability of recurrent bleeding was 18.8 percent for patients receiving eradication therapy and 4.4 percent for those treated with omeprazole (absolute difference, 14.4 percent; 95 percent confidence interval for the difference, 4.4 to 24.4 percent; P=0.005). CONCLUSIONS Among patients with H. pylori infection and a history of upper gastrointestinal bleeding who are taking low-dose aspirin, the eradication of H. pylori is equivalent to treatment with omeprazole in preventing recurrent bleeding. Omeprazole is superior to the eradication of H. pylori in preventing recurrent bleeding in patients who are taking other NSAIDs.

Screening for gastric cancer in Asia: current evidence and practice

Gastric cancer is the second most common cause of death from cancer in Asia. Although surgery is the standard treatment for this disease, early detection and treatment is the only way to reduce mortality. This Review summarises the epidemiology of gastric cancer, and the evidence for, and current practices of, screening in Asia. Few Asian countries have implemented a national screening programme for gastric cancer; most have adopted opportunistic screening of high-risk individuals only. Although screening by endoscopy seems to be the most accurate method for detection of gastric cancer, the availability of endoscopic instruments and expertise for mass screening remains questionable--even in developed countries such as Japan. Therefore, barium studies or serum-pepsinogen testing are sometimes used as the initial screening tool in some countries, and patients with abnormal results are screened by endoscopy. Despite the strong link between infection with Helicobacter pylori and gastric cancer, more data are needed to define the role of its eradication in the prevention of gastric cancer in Asia. At present, there is a paucity of quality data from Asia to lend support for screening for gastric cancer.

Combination of a cyclo-oxygenase-2 inhibitor and a proton-pump inhibitor for prevention of recurrent ulcer bleeding in patients at very high risk: a double-blind, randomised trial

BACKGROUND Guidelines on pain management recommend that patients at risk of ulcers receive either a cyclo-oxygenase (COX 2) inhibitor or a non-steroidal anti-inflammatory drug (NSAID) with a proton-pump inhibitor (PPI). These two treatments have similar effectiveness, but they are insufficient for protection of patients at very high risk for ulcer bleeding. We aimed to test the hypothesis that in patients with previous ulcer bleeding induced by non-selective NSAIDs, combined treatment with the COX 2 inhibitor celecoxib and the PPI esomeprazole would be better than celecoxib alone for prevention of recurrent ulcer bleeding. METHODS 441 consecutively presenting patients who were taking non-selective NSAIDs for arthritis were recruited to our single-centre, prospective, randomised, double-blind trial after admission to hospital with upper-gastrointestinal bleeding. Patients were enrolled after their ulcers had healed and a histological test for Helicobacter pylori was negative. All patients were given 200 mg celecoxib twice daily. 137 patients were randomly assigned to receive 20 mg esomeprazole twice daily (combined-treatment group), and 136 to receive a placebo (control group) for 12 months. The primary endpoint was recurrent ulcer bleeding during treatment or within 1 month of the end of treatment. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00365313. FINDINGS Combination treatment was more effective than celecoxib alone for prevention of ulcer bleeding in patients at high risk. The 13-month cumulative incidence of the primary endpoint was 0% in the combined-treatment group and 12 (8.9%) in the controls (95% CI difference, 4.1 to 13.7; p=0.0004). The median follow-up was 13 months (range 0.4-13.0). Discontinuation of treatment and the incidence of adverse events were similar in the two treatment groups. INTERPRETATION Patients at very high risk for recurrent ulcer bleeding who need anti-inflammatory analgesics should receive combination treatment with a COX 2 inhibitor and a PPI. Our findings should encourage guideline committees to review their recommendations for patients at very high risk of recurrent ulcer bleeding.

Cyclooxygenase-2 Expression in Helicobacter pylori-Associated Premalignant and Malignant Gastric Lesions

Expression of cyclooxygenase-2 (COX-2) in various stages of the Helicobacter pylori-associated gastric carcinogenesis pathway has not been elucidated. We investigated the distribution and intensity of COX-2 expression in premalignant and malignant gastric lesions, and monitored the changes after H. pylori eradication. Gastric biopsies from H. pylori-infected patients with chronic active gastritis, gastric atrophy, intestinal metaplasia (IM), gastric adenocarcinoma, and noninfected controls were studied. Expression of COX-2 was evaluated by immunohistochemistry and in situ hybridization. Endoscopic biopsies were repeated 1 year after successful eradication of H. pylori in a group of IM patients for comparing COX-2 expression and progression of IM. In all H. pylori-infected patients, COX-2 expression was predominantly found in the foveolar and glandular epithelium and, to a lesser extent, in the lamina propria. In the noninfected group, only 35% of cases demonstrated weak COX-2 expression. Intensity of COX-2 was not significantly different between the chronic active gastritis, gastric atrophy, IM, and gastric adenocarcinoma groups. In 17 patients with IM, COX-2 expressions in the epithelial cells and stromal cells were reduced 1 year after H. pylori eradication. However, the changes in COX-2 expression did not correlate with progression/regression of IM. Both premalignant and malignant gastric lesions demonstrate strong COX-2 expression. Successful eradication of H. pylori leads to down-regulation of COX-2 expression but failed to reverse IM at 1 year.

Enteric involvement of severe acute respiratory syndrome-associated coronavirus infection.

Abstract Background & Aims : Severe acute respiratory syndrome (SARS) is a recently emerged infection from a novel coronavirus (CoV). Apart from fever and respiratory complications, gastrointestinal symptoms are frequently observed in patients with SARS but the significance remains undetermined. Herein, we describe the clinical, pathologic, and virologic features of the intestinal involvement of this new viral infection. Methods : A retrospective analysis of the gastrointestinal symptoms and other clinical parameters of the first 138 patients with confirmed SARS admitted for a major outbreak in Hong Kong in March 2003 was performed. Intestinal specimens were obtained by colonoscopy or postmortem examination to detect the presence of coronavirus by electron microscopy, virus culture, and reverse-transcription polymerase chain reaction. Results : Among these 138 patients with SARS, 28 (20.3%) presented with watery diarrhea and up to 38.4% of patients had symptoms of diarrhea during the course of illness. Diarrhea was more frequently observed during the first week of illness. The mean number of days with diarrhea was 3.7 ± 2.7, and most diarrhea was self-limiting. Intestinal biopsy specimens obtained by colonoscopy or autopsy showed minimal architectural disruption but the presence of active viral replication within both the small and large intestine. Coronavirus was also isolated by culture from these specimens, and SARS-CoV RNA can be detected in the stool of patients for more than 10 weeks after symptom onset. Conclusions : Diarrhea is a common presenting symptom of SARS. The intestinal tropism of the SARS-CoV has major implications on clinical presentation and viral transmission.

Fecal Viral Load and Norovirus-associated Gastroenteritis

We report the median cDNA viral load of norovirus genogroup II is >100-fold higher than that of genogroup I in the fecal specimens of patients with norovirus-associated gastroenteritis. We speculate that increased cDNA viral load accounts for the higher transmissibility of genogroup II strains through the fecal-oral route.

Chemoprevention of gastric cancer by celecoxib in rats

Background: Overexpression of cyclooxygenase 2 (COX-2) is frequently detected in gastric cancer and is believed to play a crucial role in gastric carcinogenesis. Aim: We examined the chemopreventive effect of a COX-2 inhibitor in an animal model of stomach carcinogenesis. Methods: Eighty six male Wistar rats were divided into six different treatment groups: group A, water alone (n = 5); group B, N-methyl-N′-nitro-N-nitrosoguanidine (MNNG 100 μg/ml) (n = 16); group C, indomethacin (3 mg/kg/day) (n = 16); group D, celecoxib (5 mg/kg/day) (n = 17); group E, celecoxib (10 mg/kg/day) (n = 16); and group F, celecoxib (20 mg/kg/day) (n = 16). Group B–F animals were treated with 10% sodium chloride (in the initial six weeks) and MNNG in drinking water to induce adenocarinoma in the stomach. All animals received treatment for 40 weeks, and were sacrificed after death or at 48 weeks. Gastric neoplasm was evaluated by histology. Results: The incidences of gastric cancer were 0% in group A, 75% in group B, 68.8% in group C, 70.6% in group D, 18.8% in group E, and 31.3% in group F (p = 0.002, ANOVA). Compared with MNNG controls, treatment with celecoxib 10 mg/kg/day also showed lower tumour multiplicity (0.19 (0.40) v 1.00 (0.73); p = 0.004) and lower mean tumour volume (2.4 v 2805 mm3; p = 0.02). Although tumours had significantly higher COX-2 expression than their adjacent normal tissues (p<0.02), there was no significant difference in COX-2 levels among tumours in the different treatment groups. The lowest tumour prostaglandin E2 level was found in the indomethacin treated group, suggesting that the chemopreventive effect of celecoxib may be mediated by a COX independent pathway. Conclusion: While treatment with indomethacin had no significant effect on tumour development, treatment with celecoxib reduced gastric cancer incidence and growth in rats.

Long-term follow-up of patients with obscure gastrointestinal bleeding after negative capsule endoscopy

BACKGROUND AND AIMS:Capsule endoscopy (CE) is one of the widely accepted investigations for obscure gastrointestinal bleeding (OGIB), but little is known about the impact of CE on the long-term outcome of patients with OGIB. We studied the long-term outcome of patients with OGIB after CE examination.PATIENTS AND METHODS:Forty-nine consecutive patients (45% men, mean age 58.3 yr) who underwent CE for OGIB were studied. The most clinically relevant finding that was related to bleeding was identified by CE. All patients were followed up for at least 12 months for clinical overt and occult bleeding.RESULTS:The median follow-up was 19 months (range 12 to 31). Possible bleeding lesions were detected by CE in 31 (63.3%) patients, and 15 (30.6%) patients, underwent further interventions including laparotomy and push enteroscopy. The overall long-term rebleeding rate in this cohort was 32.7%. The cumulative rebleeding rate was significantly lower in patients with a negative CE (5.6%) than in patients with a positive CE (48.4%, p = 0.03 log-rank test). The sensitivity and negative predictive value of CE in predicting rebleeding were 93.8% and 94.4%, respectively.CONCLUSIONS:Patients with OGIB and negative CE had a very low rebleeding rate, and further invasive investigations can be deferred.

Concurrent hypermethylation of multiple tumor-related genes in gastric carcinoma and adjacent normal tissues

Transcriptional silencing by CpG‐island hypermethylation now is believed to be an important mechanism of tumorigenesis. To date, studies on CpG‐island hypermethylation in gastric carcinoma and adjacent normal tissues are few.

Promoter hypermethylation of tumor-related genes in gastric intestinal metaplasia of patients with and without gastric cancer

Promoter hypermethylation is an alternative mechanism of gene silencing in human cancers including gastric cancer. While intestinal metaplasia (IM) is generally regarded as a precancerous lesion of the stomach, our study examines the presence of gene promoter hypermethylation in IM of patients with and without gastric cancer. We examined 31 samples of gastric cancer, 36 gastric IM (21 associated with gastric cancer and 15 from noncancer patients) and 10 normal gastric biopsies. Tissues containing foci of IM were carefully microdissected from paraffin‐embedded section. Bisulfite‐modifiedDNA was examined for gene promoter hypermethylation in DAP‐kinase, E‐cadherin, GSTP1, p14, p15, p16, RASSF1A and hMLH1 by methylation‐specific‐PCR. None of the control gastric tissues had hypermethylation detected, but gene promoter hypermethylation was frequently detected in gastric cancer and IM. The mean number of methylated genes in cancer and IM was 3.0 and 1.4, respectively (p < 0.0001). Methylation in IM from cancer patients was all associated with concurrent methylation in the corresponding tumor samples. The numbers of methylated genes were similar in IM obtained from cancer and noncancer patients. By examining the methylation patterns of these genes, 3 differential methylation patterns were recognized: hypermethylation was more frequent in cancer than in IM (DAP‐kinase, p14, p15 and p16); comparable frequencies of methylation in cancer and IM (E‐cadherin and hMLH1); and no methylation (GSTP1). Aberrant methylation in tumor‐related genes is frequently detected in gastric IM of both cancer and noncancer patients, suggesting their early involvement in the multistep progression of gastric carcinogenesis.