Octreotide-based therapies effectively protect mice from acute and chronic gastritis.

Gastritis is a common inflammation of stomach with multiple pathogenesis. This study was designed to investigate the protective effects of oral octreotide (OCT) against ethanol-induced acute gastric injury and H. pylori-induced chronic gastritis via promoting gastric mucosa restoration, reducing gastric acid secretion and inflammation. Male C57BL/6J mice were randomly divided and treated with three doses of OCT (0.5, 2.5, 10 mg/kg) alone or combined respectively with 10 mg/kg omeprazole (OME), 0.2 g/L metronidazole (MTZ)/0.1 g/L clarithromycin (CLR) in drinking water. Oxidative stress analysis, bacterial load analysis, qPCR, gastric histopathology examinations were performed in our study. Ethanol-induced acute gastric ulcer was restored by OCT alone at doses of 2.5 mg/kg, or combined with OME as indicated by markedly reducing Gastrin, Il-6 and Il1b expression through induction of Muc5ac and Occludin, significantly improving hyperacidity and gastric bleeding. As well, OCT combined with MTZ/CLR restored the integrity of gastric mucosa damaged by H. pylori via elevating the expression of Muc5ac and somatostatin receptor 2, decreasing inflammation and increasing the number of chorionic or glands. Besides, OCT is more suitable for long-term medication in the treatment of chronic gastritis than OME. In conclusion, our results proved that the newly developed oral OCT-based therapies were more effective to reverse gastric mucosa damage and inflammation in ethanol and H. pylori infection-induced gastric injury, it is of great significance for supplementing new clinical regimens for the treatment of acute and chronic gastritis.

Antibacterial effect of Kampo herbal formulation Hochu-ekki-to (Bu-Zhong-Yi-Qi-Tang) on Helicobacter pylori infection in mice.

Because Helicobacter pylori (H. pylori) infection is a major cause of gastroduodenal diseases in humans, the eradication of H. pylori using antibiotics is very effective for the treatment of gastroduodenal diseases. However, it has recently been reported that resistance to these antibiotics is developing. In the present study, the antibacterial effect of a Kampo (traditional Japanese medicine) herbal formulation, Hochu-ekki-to (RET; Formula repletionis animalis et supletionis medii), against H. pylori was examined in vitro and in vivo. HET inhibited the growth of antibiotic-resistant strains of H. pylori as well as antibiotic-sensitive strains at a dose of 2.5 mg/ml in vitro. When 1,000 mg/kg of HET was administered orally to C57BL/6 mice for 7 days before or after inoculation with H. pylori, H. pylori in the stomach was significantly reduced in the HET-pre-treatment group compared with the control group. Furthermore, HET in combination with antibiotics completely eradicated the bacteria in mice. The expression of interferon (IFN)-gamma was induced in the gastric mucosa of the mice pre-treated with HET. There were no significant differences between the colonization of H. pylori in the control and HET treatment groups in IFN-gamma gene-deficient mice. These results suggest that the antibacterial effect of HET may be partly due to IFN-gamma induction, and that HET may be clinically useful for treatment of H. pylori infection.

Requirements for intracellular accumulation and release of clarithromycin and azithromycin by human phagocytes.

Determination of clarithromycin (CL) and azithromycin (AZ) uptake by human polymorphonuclear leukocytes (PMNs), monocytes and alveolar macrophages showed that AZ achieved higher levels than CL. The uptake kinetics of AZ were time-dependent over an 18 h period, while those of CL were similar to erythromycin (ER) kinetics, with a maximum level of incorporation being obtained after a 60 min incubation. The accumulation of both drugs was influenced by extracellular antibiotic-concentrations, PMN viability, extracellular calcium, physiological environmental temperature and pH. The uptake was not modified by inhibitors of cell metabolism or activators of cell membranes. After removal of extracellular antibiotic, the release of AZ from PMNs was very slow: nearly 50% of the drug remained cell-associated after 24 h incubation. The efflux of this derivative was significantly enhanced when drug-loaded PMNs were stimulated by phorbol-myristate acetate (PMA). The kinetics of CL release indicated that this macrolide behaved like ER. Nevertheless, about 10% of the initial cell-associated antibiotic showed a prolonged retention. On the whole, these data suggest that diffusion through cell membranes and trapping into acidic compartments of PMNs are important events in CL and AZ uptake.

Acquired resistance in Mycobacterium avium complex strains isolated from AIDS patients and beige mice during treatment with clarithromycin.

Clarithromycin has been reported to select clarithromycin resistant mutants of Mycobacterium avium complex (MAC) during treatment with clarithromycin in AIDS patients and beige mice. We selected resistant mutants in vitro at a frequency of 5 x 10(-9). Clarithromycin resistant strains of MAC isolated in AIDS patients and beige mice as well as derivatives selected in vitro had a unique pattern of acquired cross-resistance to macrolides and related antibiotics. In contrast, the pattern of resistance to non-macrolide antibiotics remained unchanged in clarithromycin resistant strains. A dramatic decrease in ribosome affinity for clarithromycin and erythromycin was found in clarithromycin resistant strains, but no mutation was found in the peptidyl domain of the 23S rRNA, indicating that another ribosomal modification is involved.