Increased activity of Pgp multidrug transporter in patients with Helicobacter pylori infection

AIM: To determine whether local antibiotic resistance involves P-glycoprotein (Pgp)-mediated active drug outpumping during Helicobacter pylori ( H pylori) infection treatment with classic antibiotic therapy. METHODS: Pgp activity was determined in gastric mucosa biopsy specimens obtained from 53 patients with pathohistologically verified gastritis and microbiologically confirmed H pylori infection, and compared with the Pgp activity in 12 control subjects with normal endoscopic findings. TheH pylori positive patients were treated with short-term 7-d therapy consisting of two antibiotics (amoxicillin and azithromycin/metronidazole and clarithromycin) and a proton pump inhibitor. Pgp activity was determined by flow cytometry in the test of rhodamine dye efflux and quantified as mean fluorescence ratio (RMF).RESULTS: Upon the first cycle,H pylori was successfully eradicated in 20 patients, whereas therapy was continued in 33 patients. In the course of antibiotic therapy, RMF increased (P＜0.05) and gastric cells showed higher rhodamine dye efflux. The mean pre-treatment RMF values were also higher (P＜0.0001) in patients with multiple therapeutic failure than in those with successful H pylorieradication and control subjects.CONCLUSION: Pgp might be one of the causes of therapy failure in patients with H pylori and antibiotic therapy could be chosen and followed up on the basis of the Pgp transporter local activity.

Influence of various proton pump inhibitors on intestinal metaplasia in noneradicated Helicobacter pylori patients

AIM: Intestinal metaplasia (IM) is more often found in patients with Helicobacter pylori (H pylori) infection, while eradication of H pylori results in significant reduction in the severity and activity of chronic gastritis. We aimed to determine in patients with unsuccessful eradication of H pylori the role of various proton pump inhibitors (PPIs) having different mechanisms in the resolution of IM. METHODS: We confirmed endoscopically and pathohistologically (Sydney classification) the IM in 335 patients with gastritis before and after medication for eradication of H pylori (Maastricht Protocol 2002). H pylori infection was determined by using histology, urease test and culture. Control endoscopy and histology were done after 30d and thereafter (within 1year). Unsuccessful eradication was considered if only one of the three tests (histology, urease and culture) was negative after therapy protocol. We used omeprazole, pantoprazole, lansoprazole in therapy protocols (in combination with two antibiotics).RESULTS: We found no significant difference in resolution of IM by using different PPI between the groups of eradicated and noneradicated patients (P<0.4821 and P<0.4388, respectively).CONCLUSION: There is no significant difference in resolution of intestinal metaplasia by different proton pump inhibitors.