Suppression of Helicobacter pylori urease activity by sucralfate and sulglycotide

Sofalcone, a mucoprotective agent, increases the cure rate of Helicobacter pylori infection when combined with rabeprazole, amoxicillin and clarithromycin

AIM: The mucoprotective agents, sofalcone and polaprezinc have anti-Helicobacter pylori (H pylori) activities. We determined the therapeutic effects of sofalcone and polaprezinc when combined with rabeprazole, amoxicillin and clarithromycin for Helicobacter pylori infection.

METHODS: One hundred and sixty-five consecutive outpatients with peptic ulcer and H pylori infection were randomly assigned to one of the following three groups and medicated for 7 d. Group A: triple therapy with rabeprazole (10 mg twice daily), clarithromycin (200 mg twice daily) and amoxicillin (750 mg twice daily). Group B: sofalcone (100 mg thrice daily) plus the triple therapy. Group C: polaprezinc (150 mg twice daily) plus the triple therapy. Eradication was considered successful if 13C-urea breath test was negative at least 4 wk after cessation of eradication regimens or successive famotidine in the cases of active peptic ulcer.

RESULTS: On intention-to-treat basis, H pylori cure was achieved in 43 of 55 (78.2%) patients, 47 of 54 (87.0%) and 45 of 56 (80.4%) for the groups A, B and C respectively. Using per protocol analysis, the eradication rates were 81.1% (43/53), 94.0% (47/50) and 84.9% (45/53) respectively. There was a significant difference in the cure rates between group A and B. Adverse events occurred in 10, 12 and 11 patients, from groups A, B and C respectively, but the events were generally mild.

CONCLUSION: The addition of sofalcone, but not polaprezinc, significantly increased the cure rate of H pylori infection when combined with the rabeprazole-amoxicillin-clarithromycin regimen.

Effect of sucralfate on antibiotic therapy for Helicobacter pylori infection in mice

It has been documented that sucralfate, a basic aluminum salt, enhances the efficacies of antibiotics against Helicobacter pylori, resulting in eradication rates comparable to those associated with the use of proton pump inhibitors. However, its mechanism of action remains unclear. The aim of the present study was to investigate sucralfate's ability to complement antibiotic treatment of H. pylori infection in vivo. Four weeks following induced H. pylori infection, clarithromycin (CAM) and amoxicillin (AMPC) were administered orally to C57BL/6 mice for 5 days, both with and without sucralfate or lansoprazole. When sucralfate was concurrently given with CAM and AMPC at the maximum noninhibitory doses for the treatment of H. pylori infection, the bacterial clearance rates were comparable to those achieved by treatment with lansoprazole plus those antibiotics. The results of pharmacokinetic studies showed that lansoprazole delayed gastric clearance and accelerated the absorption of CAM, whereas sucralfate suppressed both gastric clearance and absorption. AMPC was undetectable in all samples. Scanning electron microscopy with a microscope to which a energy dispersive spectrometer was attached revealed that aluminum-containing aggregated substances coated the mucosa surrounding H. pylori in mice receiving sucralfate plus antibiotics, whereas the gastric surface and pits where H. pylori had attached were clearly visible in mice receiving lansoprazole plus antibiotics. The addition of sucralfate to the antibiotic suspension resulted in a more viscous mixture that bound to the H. pylori-infected mucosa and that inhibited the loss of CAM bioavailability in the acidic environment. Sucralfate delays gastric clearance of CAM and physically captures H. pylori through the creation of an adherent mucus, which leads to bacterial clearance.

Gastric mucosal inflammatory responses toHelicobacter pylori lipopolysaccharide: suppression of caspase-3 and nitric oxide synthase-2 by omeprazole and sucralfate

AIMS

Helicobacter pylori lipopolysaccharide is a primary virulence factor responsible for eliciting acute mucosal inflammatory responses associated with H. pylori infection. In this study, we investigated the activity of a key apoptotic protease, caspase-3, and the expression of inducible nitric oxide synthase (NOS-2) during H. pylori lipopolysaccharide-induced acute gastritis, and evaluated the effect of anti-ulcer agents, omeprazole and sucralfate, on this process.

METHODS

Rats, pretreated twice daily with omeprazole at 40 mg/kg, sucralfate at 100 mg/kg, or the vehicle, were subjected to intragastric application of H. pylori lipopolysaccharide at 50 microg/animal, and after 4 additional days on the anti-ulcer drug or vehicle regimen their mucosal tissue was used for histologic assessment, assays of epithelial cells apoptosis, and the measurements of caspase-3 and NOS-2 activities.

RESULTS

In the absence of anti-ulcer agents,H. pylori lipopolysaccharide induced acute reaction characterized by the inflammatory infiltration of the lamina propria, hyperemia, and epithelial hemorrhage. This was accompanied by an 11.2-fold increase in epithelial cell apoptosis, a 6.5-fold induction in mucosal expression of NOS-2, and a 5.4-fold increase in caspase-3 activity. Treatment with proton pump inhibitor, omeprazole, produced a 39.6% reduction in the extent of mucosal inflammatory changes elicited by H. pylori lipopolysaccharide and a 75.5% decrease in the epithelial cells apoptosis, while the activity of caspase-3 decreased by 26.8% and that of NOS-2 showed a 46.7% decline. The gastroprotective agent, sucralfate, evoked a 62.3% reduction in the extent of mucosal inflammatory changes caused by the lipopolysaccharide, epithelial cell apoptosis decreased by 85.8%, and NOS-2 showed a 68.2% decline, while the activity of caspase-3 decreased by 39.7%.

CONCLUSIONS

Our findings implicate caspase-3 involvement in gastric mucosal inflammatory responses toH. pylori lipopolysaccharide, and point towards participation of NOS-2 in the amplification of the cell death-signaling cascade. We also show that anti-ulcer agents, omeprazole and sucralfate, are capable of suppressing the H. pylori-induced mucosal inflammatory responses by interfering with the events propagated by NOS-2 and caspase-3.