Effects of a one-week treatment with acid gastric inhibitors on Helicobacter pylori-infected mice

Phenobarbital Treatment at a Neonatal Age Results in Decreased Efficacy of Omeprazole in Adult Mice

Drug-drug interactions (DDIs) occur when the action of one drug interferes with or alters the activity of another drug taken concomitantly. This can lead to decreased drug efficacy or increased toxicity. Because of DDIs, physicians in the clinical practice attempt to avoid potential interactions when multiple drugs are coadministrated; however, there is still a large knowledge gap in understanding how drugs taken in the past can contribute to DDIs in the future. The goal of this study was to investigate the consequence of neonatal drug exposure on efficacy of other drugs administered up through adult life. We selected a mouse model to test phenobarbital exposure at a neonatal age and its impact on efficacy of omeprazole in adult life. The results of our experiment show an observed decrease in omeprazole's ability to raise gastric pH in adult mice that received single or multiple doses of phenobarbital at a neonatal age. This effect may be associated with the permanent induction of cytochrome P450 enzymes in adult liver after neonatal phenobarbital treatment. Our data indicates that DDIs may result from drugs administered in the past in an animal model and should prompt re-evaluation of how DDIs are viewed and how to avoid long-term DDIs in clinical practice.

Mouse models for gastric cancer: Matching models to biological questions

Gastric cancer is the third leading cause of cancer-related mortality worldwide. This is in part due to the asymptomatic nature of the disease, which often results in late-stage diagnosis, at which point there are limited treatment options. Even when treated successfully, gastric cancer patients have a high risk of tumor recurrence and acquired drug resistance. It is vital to gain a better understanding of the molecular mechanisms underlying gastric cancer pathogenesis to facilitate the design of new-targeted therapies that may improve patient survival. A number of chemically and genetically engineered mouse models of gastric cancer have provided significant insight into the contribution of genetic and environmental factors to disease onset and progression. This review outlines the strengths and limitations of current mouse models of gastric cancer and their relevance to the pre-clinical development of new therapeutics.

Effect of omeprazole dose, nonsteroidal anti-inflammatory agents, and smoking on repair mechanisms in acute peptic ulcer bleeding

BACKGROUND

Peptic ulcer bleeding (PUB) is a major cause of upper gastrointestinal bleeding. The effect of omeprazole on mucosal repair is unknown.

AIMS

We studied the effect of omeprazole, nonsteroidal anti-inflammatory agents, and smoking on PUB.

METHODS

There were 43 PUB patients who received regular or high dose of omeprazole for 72 h. Biopsies from antrum and corpus were taken before and after treatment. Biopsy samples from 20 celiac disease patients worked as controls. The expression of Ki-67, Bcl-2, COX-2, Hsp27, and Hsp70 was analyzed from patients and controls.

RESULTS

Bcl-2 expression in PUB patients was lower than in controls. However, Bcl-2 increased significantly from 5.0 (SD 4.5) to 9.1 % (SD 6.7), p = 0.0004, in the antrum after omeprazole. In univariate analysis, a high omeprazole dose caused a more profound increase in Ki-67 expression in the corpus: 35.3 % (SD 54.8) than a regular dose: -10.1 % (SD 40.6), p = 0.022. In multivariate analysis, Ki-67 decreased significantly in the corpus between the pre- and posttreatment period (p = 0.011), while a high omeprazole dose (p = 0.0265), the use of NSAIDs (p = 0.0208), and smoking (p = 0.0296) significantly increased Ki-67 expression. Bcl-2 in the corpus increased significantly (p = 0.0003) after treatment.

CONCLUSIONS

Our findings suggest that Bcl-2 may be an important factor in the pathogenesis of a peptic ulcer and PUB. In addition, high-dose omeprazole increased the expression of Ki-67, which may enhance the healing process of a peptic ulcer.

The effect on serum myeloperoxidase activity and oxidative status of eradication treatment in patients Helicobacter pylori infected

OBJECTIVES

Myeloperoxidase activity has been investigated after eradication of Helicobacter pylori (H. pylori) in infected patients in previous studies but the results are controversial. The aim of this study was to investigate effect on serum myeloperoxidase activity and oxidative status of eradication treatment in H. pylori-infected patients.

DESIGN AND METHODS

Gastric biopsy specimens were obtained from 30 H. pylori infected patients. Serum myeloperoxidase activity was measured by enzyme-linked immunoassay. Oxidative status was determined using total antioxidant capacity (TAC) and total oxidant status (TOS) measurement and calculation of oxidative stress index (OSI).

RESULTS

After 2 weeks of the eradication treatment, serum myeloperoxidase activity, TOS and OSI values were significantly lower (all; p<0.001), while TAC was significantly higher (p<0.001).

CONCLUSIONS

Our results indicate that eradication treatment in H. pylori-infected patients may affect both oxidative stress and myeloperoxidase activity which is an important biomarker in pathogenesis of atherosclerosis.