Abstracts: North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition Annual Meeting October 20-22, 2005 Salt Lake City, Utah: POSTER SESSION II FRIDAY, OCTOBER 21, 2005 12:15PM - 2:15PM: Basic Science
Helicobacter pylori, a gram-negative spiral bacterium, infects half the worlds population and has been associated with peptic ulcers and gastric cancers. Many non-human primates are naturally colonized with helicobacter species and we sought to characterize gastric bacterial infection of baboons.
Materials and Methods:
Baboons at the Oklahoma University Health Sciences Center are maintained in three groups. 1) Free living animals in half-acre corrals housing 60 to 70 animals. 2) Specific pathogen free (SPF) animals,hand reared from birth. These animals are regularly tested for simian viruses and animals that test positive are removed to traditional caging (SPF dropout animals) and are exposed to corral baboons. 4-6 animals from each group were endoscoped and biopsies were obtained for culture, histopathology and Steiner (silver) staining. Blood was also obtained.
1) SPF animals had a normal appearing mucosa on endoscopy. The SPF dropout group was noted to have erythematous gastric mucosa with thickened pyloric folds. The corral baboons had a similar appearance to the SPF dropout group and 2 of 5 animals exhibited ulcers in the pyloric region. 2) The biopsies from all animals failed to grow out any bacteria with characteristics typical of H. pylori (colony morphology, urease,catalase,oxidase positivity), although occasionally some biopsies did yield unidentified colonies. 3) Examination of steiner stained sections revealed that the two non-SPF groups were moderately to heavily colonized with a spiral bacteria consistent with H. heilmanii or a related organism. 4) Histopathology of SPF animals was consistent with gross endoscopic appearance (normal healthy mucosa). The SPF dropout animals had minimal to very mild inflammation. The corral animals exhibited moderate to severe patchy infiltration of mononuclear cells, PMNs and small lymphocyte aggregates.
The results suggest that the baboon may be an excellent model to study H. pylori pathogenesis. Efforts are also underway to infect the SPF animals with H. pylori.