CYP2C19 polymorphism influences Helicobacter pylori eradication

The known factors that have contributed to the decline of Helicobacter pylori (H. pylori) eradication rate include antibiotic resistance, poor compliance, high gastric acidity, high bacterial load, and cytochrome P450 2C19 (CYP2C19) polymorphism. Proton pump inhibitor (PPI) is important in the eradication regimen. The principal enzyme implicated in the metabolism of PPIs is CYP2C19. The effects of PPI depend on metabolic enzyme, cytochrome P450 enzymes, and CYP2C19 with genetic differences in the activity of this enzyme (the homozygous EM, heterozygous EM (HetEM), and poor metabolizer). The frequency of the CYP2C19 polymorphism is highly varied among different ethnic populations. The CYP2C19 genotype is a cardinal factor of H. pylori eradication in patients taking omeprazole- based or lansoprazole-based triple therapies. In contrast, the CYP2C19 polymorphism has no significant effect on the rabeprazole-based or esomeprazole-based triple therapies. The efficacy of levofloxacin-based rescue triple therapy might be also affected by the CYP2C19 polymorphism, but CYP2C19 genotypes did not show obvious impact on other levofloxacin-based rescue therapies. Choice of different PPIs and/or increasing doses of PPIs should be individualized based on the pharmacogenetics background of each patient and pharmacological profile of each drug. Other possible factors influencing gastric acid secretion (e.g., IL-1β- 511 polymorphism) would be also under consideration.

Diagnosis of Helicobacter pylori infection: Current options and developments

Accurate diagnosis of Helicobacter pylori(H. pylori) infection is a crucial part in the effective management of many gastroduodenal diseases. Several invasive and non-invasive diagnostic tests are available for the detection of H. pylori and each test has its usefulness and limitations in different clinical situations. Although none can be considered as a single gold standard in clinical practice,several techniques have been developed to give the more reliable results. Invasive tests are performed via endoscopic biopsy specimens and these tests include histology,culture,rapid urease test as well as molecular methods. Developments of endoscopic equipment also contribute to the real-time diagnosis of H. pylori during endoscopy. Urea breathingtest and stool antigen test are most widely used noninvasive tests,whereas serology is useful in screening and epidemiological studies. Molecular methods have been used in variable specimens other than gastric mucosa. More than detection of H. pylori infection,several tests are introduced into the evaluation of virulence factors and antibiotic sensitivity of H. pylori,as well as screening precancerous lesions and gastric cancer. The aim of this article is to review the current options and novel developments of diagnostic tests and their applications in different clinical conditions or for specific purposes.

Capsaicin-induced cell death in a human gastric adenocarcinoma cell line

AIM Capsaicin, a pungent ingredient found in red pepper, has long been used in spices, food additives, and drugs. Cell death induced by the binding of capsaidn was examined in a human gastric adenocarcinoma cell line （AGS cells）. METHODS： By using XTT-based cytotoxicity assay, flow cytometry using the TUNEL method, and quantitation of DNA fragmentation, both cell death and DNA fragmentaUon were detected in AGS cells treated with capsaicin. By using Western blotting methods, capsaicin reduced the expression of Bcl-2, the antiapoptotic protein, in AGS cells in a concentration-dependent manner. RESULTS- After incubation of AGS cells with capsaicin for 24 h, cell viability decreased significantly in a dose-dependent manner. After incubation of AGS cells with capsaicin for 24 h, apoptotic bodies also significantly increased, and were again correlated with the dose of capsaicin. When the concentration of capsaicin was 1 mmol/L, the amount of DNA fragments also increased. Similar results were also in the lower traces. CONCLUSION： These results suggest that capsaicin- induced cell death might be via a Bcl-2 sensitive apoptotic pathway. Therefore, capsaicin might induce protection from gastric cancer.

Evaluation of urine ELISA test for detecting Helicobacter pylori infection in Taiwan: A prospective study

AIM： To evaluate the diagnostic accuracy and clinical utility of a new ELISA （URINELISA） test for detecting Helicobacter pylori （H pylorl） antibody in the urine of Taiwan Residents population. METHODS： In this prospective study, 317 consecutive dyspeptic patients （171 men, 146 women; mean age, 51.0 years） were included. They underwent gastroendoscopy for evaluation. Invasive tests, including culture, histology, and rapid urease test （RUT）, and non-invasive ^13C-urea breath test were preformed. At the same time, urine specimens were collected for URINELISA. The status of H pylori infection was considered as positive when either culture was positive, or when two of the other, RUT, histology or 13C-UBT, were positive. RESULTS： The sensitivity, specificity, positive predictive value, and negative predictive value of URINELISA are 91.7% （211/230）, 90.8% （79/87）, 96.3% （211/219）, and 80.6% （79/98） respectively. CONCLUSION： This URINELISA test is reliable, inexpensive and easy-to-use. The high diagnostic accuracy warrants the use of URINELISA as a first-line screening tool for diagnosis of Hpyloriinfection in untreated patients.