Enhancement in the protective qualities of gastric mucus by ebrotidine during duodenal ulcer healing

Enhancement in the protective qualities of gastric mucus with combination therapy of ebrotidine and amoxicillin for H. pylori eradication

1. Gastric mucus from Helicobacter pylori-positive patients with active chronic gastritis type B, before and after successful combination therapy consisting of the H2 receptor antagonist ebrotidine (400 mg) and amoxicillin (1,000 mg) administered b.i.d., in the morning and at bedtime for a period of 2 weeks followed by administration of ebrotidine alone for the subsequent 4 weeks, was assessed for the changes in physicochemical properties associated with the mucosal protective potential and anti-H. pylori activity. 2. The results of physicochemical measurements revealed that eradication of H. pylori associated with the successful therapy for active chronic gastritis type B with ebrotidine-amoxicillin was accompanied by a 36% increase in gastric mucus hydrogen ion retardation capacity, a 1.5-2.1-fold increase in mucus gel viscosity and a 2.4-fold increase in its hydrophobicity. 3. The beneficial changes brought about by the ebrotidine-amoxicillin therapy in the physical properties of gastric mucus were also manifest in a 2.7-fold enhancement in the proportion of the high-molecular-weight polymeric mucin form responsible for the maintenance of gastric mucus gel integrity. 4. Moreover, assays of H. pylori aggregating titer of gastric mucus revealed that the successful combination therapy with ebrotidine and amoxicillin led to a 3.8-fold increase in mucin anti-H. pylori activity. 5. The results demonstrate that combination therapy with ebrotidine and amoxicillin for H. pylori eradication leads to a marked improvement in the protective qualities of gastric mucus essential for the preservation of mucosal integrity and enhances the inherent mucosal defense against H. pylori infection.

Induction of tumor necrosis factor-alpha and apoptosis in gastric mucosal injury by indomethacin: effect of omeprazole and ebrotidine

BACKGROUND

The gastric injury associated with nonsteroidal anti-inflammatory drug (NSAID) therapy has been linked to the detrimental effects of the agents on the processes of prostaglandin generation, leukocyte adherence, superoxides production, and mucosal cell proliferation. In the present study we investigated the expression of tumor necrosis factor-alpha (TNF-alpha) and epithelial cell apoptosis during indomethacin-induced gastric mucosal injury and evaluated the effect of two antiulcer agents on this process.

METHODS

The experiments were carried out with groups of rats subjected to intragastric pretreatment with 40 mg/kg omeprazole, 100 mg/kg ebrotidine, or vehicle, followed 30 min later by an intragastric dose of indomethacin at 60 mg/kg. After 2 h the animals were killed, and the gastric mucosal tissue used for macroscopic damage assessment, quantitation of TNF-alpha expression, and the assay of epithelial cell apoptosis.

RESULTS

In the absence of antiulcer drugs, indomethacin caused extensive multiple hemorrhagic lesions accompanied by a 47% increase in mucosal expression of TNF-alpha and a dramatic (> 300-fold) enhancement in gastric epithelial cell apoptosis. Pretreatment with a proton pump inhibitor, omeprazole, produced only marginal (6-8%) reduction in the extent of mucosal damage caused by indomethacin, whereas the mucosal expression of TNF-alpha decreased by 15% and the apoptotic DNA fragmentation by 10-13%. In contrast, the H2-receptor antagonist ebrotidine, also known for its gastroprotective effects, not only successfully prevented (98.3%) the enhancement in mucosal TNF-alpha expression caused by indomethacin but also caused a 54% reduction in the epithelial cell apoptosis. These effects of ebrotidine were, furthermore, reflected in a 90.2% prevention in the gastric mucosal damage.

CONCLUSIONS

Our findings provide new insights into the mechanism of gastric injury caused by NSAIDs and show that ebrotidine protection against indomethacin-induced mucosal damage occurs through the inhibition of epithelial cell apoptosis triggered by the enhancement in the mucosal TNF-alpha expression. Our data also show that omeprazole does not possess antiapoptotic properties.

Reversal of gastric somatostatin receptor inhibition by Helicobacter pylori lipopolysaccharide with ebrotidine and sulglycotide

1. Among the consequences of H. pylori infection is an increase in gastric acid secretion due to the impairement in feedback inhibition by somatostatin. Here, we show that lipopolysaccharide from H. pylori inhibits the binding of somatostatin to gastric mucosal receptor, and that antiulcer agents, ebrotidine and sulglycotide, are capable of countering this effect. 2. The somatostatin receptor was prepared from the solubilized gastric mucosal epithelial cell membranes by affinity chromatography on Affi-Gel-bound [D-Tryp8] SRIF-14 and used in the binding assays for 125I-labeled somatostatin in the presence of H. pylori lipopolysaccharide and antiulcer agents. 3. The assays revealed a dose-dependent inhibition in the receptor-somatostatin binding by the lipopolysaccharide which reached a maximum of 94.1%. The effect of H. pylori lipopolysaccharide was countered by ebrotidine and sulglycotide, which at their optimal doses produced 94.9% and 84% restoration in somatostatin-receptor binding, respectively. 4. The results demonstrate that the antiulcer agents, ebrotidine and sulglycotide, possess the ability to counteract the H. pylori interference with somatostatin regulatory effect on gastric acid secretion.