OBJECTIVE: The purpose of this study was to investigate the influence of P-gp modulation on the efficacy of treatment regimen.
METHOD: P-gp modulation in rats was performed by using P-gp inducer (150 mg/kg rifampicin) and P-gp inhibitor (10 mg/kg cyclosporine A) for 14 days prior to be infected with Helicobacter pylori (H. pylori). The rats were further divided into groups, which were normal control, vehicle control, antibiotics and omeprazole, antibiotics only and omeprazole only for another 2 weeks of treatment. The ulcer formation and P-gp expression were determined by using macroscopic evaluation and western blot analysis, respectively.
RESULTS: The highest P-gp expression was shown in the induced P-gp rats (2.00 ± 0.68) while the lowest P-gp expression was shown in the inhibited P-gp rats (0.45 ± 0.36) compared to the normal P-gp rats. In all groups, the rats which were infected with H. pylori, had a significant increase (p ulcer formation compared to the healthy rats. The ulcer developed at different levels in the rats with inhibited, induced, or normal P-gp expression. After receiving the standard therapy for H. pylori, it was observed that the healing rate for ulcer was increased to 91% (rats with inhibited P-gp expression), 82% (rats with induced P-gp expression) and 75% in rats with normal P-gp. The use of rifampicin to induce P-gp level was also shown to be effective in eradicating the H. pylori infection.
CONCLUSION: The synergism in the standard therapy by using two antibiotics (clarithromycin and amoxicillin) and proton pump inhibitor (omeprazole) have shown to effectively eradicate the H. pylori infection. Thus, P-gp expression influenced the effectiveness of the treatment.
METHODOLOGY: The experimental set included different animal groups. Specifically, four groups with gastric mucosal lesions were receiving either a) Ulcer control group treated with absolute ethanol (5 ml/kg), b) 20 mg/kg of omeprazole as reference group, c) 25 of biochanin A, d) 50 mg/kg of biochanin A. Histopathological sectioning followed by immunohistochemistry staining were undertaken to evaluate the influence of the different treatments on gastric wall mucosal layer. The gastric secretions were collected in the form of homogenate and exposed to superoxide dismutase (SOD) and nitric oxide enzyme (NO) and the level of malondialdehyde (MDA) and protein content were measured. Ulceration and patchy haemorrhage were clearly observed by light microscopy. The morphology of the gastric wall as confirmed by immunohistochemistry and fluorescent microscopic observations, exhibited sever deformity with notable thickness, oedematous and complete loss of the mucosal coverage however the biochanin-pretreated animals, similar to the omeprazole-pretreated animals, showed less damage compared to the ulcer control group. Moreover, up-regulation of Hsp70 protein and down-regulation of Bax protein were detected in the biochanin A pre-treated groups and the gastric glandular mucosa was positively stained with Periodic Acid Schiff (PAS) staining and the Leucocytes infiltration was commonly seen. Biochanin A displayed a great increase in SOD and NO levels and decreased the release of MDA.
CONCLUSIONS: This gastroprotective effect of biochanin A could be attributed to the enhancement of cellular metabolic cycles perceived as an increase in the SOD, NO activity, and decrease in the level of MDA, and also decrease in level of Bax expression and increase the Hsp70 expression level.
PATIENTS AND METHODS: Patients with unequivocal evidence of H. pylori infection based on culture, histology and rapid urease test of both antrum and corpus biopsies were recruited for the study. The study was a randomized, investigator-blind, comparative study. Patients received either omeprazole 20 mg o.m., clarithromycin 250 mg b.d. and amoxycillin 500 mg b.d. (OAC) or omeprazole 20 mg o.m., metronidazole 400 mg b.d. and clarithromycin 250 mg b.d. (OMC) for 1 week. Patients were assessed for successful eradication, which was defined as absence of bacteria in all tests (culture, histology and urease test on both antral and corpus biopsies), at least 4 weeks after completion of therapy.
RESULTS: Eighty-two patients were recruited for the study. Eradication rates on intention-to-treat analysis were--OAC: 36/41 (87.8%, 95% CI: 73.8, 95.9); OMC: 33/41 (80.5%, 95% CI: 65.1, 91.2). On per protocol analysis were--OAC: 36/40 (90%, 95% CI: 76.3, 97.2); OMC: 32/38 (84.2%, 95% CI: 68.7, 94.0). All side-effects encountered were mild and no patient discontinued treatment because of intolerance to medications. The most common side-effects were altered taste (OAC 31.7%, OMC 53.7%) and lethargy (OAC 14.6%, OMC 19.5%). Pre-treatment metronidazole resistance was encountered in 34/63 (54.0%) patients. No bacterial strains were found with primary resistance to clarithromycin. Metronidazole resistance did not significantly affect eradication rates. Emergence of resistance to clarithromycin was not seen post-therapy.
CONCLUSIONS: Both the OAC and the OMC regimens were convenient and well-tolerated treatments for H. pylori. However, eradication rates were lower than anticipated.