Porphyromonas gingivalis Lipopolysaccharide Damages Mucosal Barrier to Promote Gastritis-Associated Carcinogenesis.

BACKGROUND: Recent epidemiological studies suggested correlation between gastric cancer (GC) and periodontal disease. AIMS: We aim to clarify involvement of lipopolysaccharide of Porphyromonas gingivalis (Pg.), one of the red complex periodontal pathogens, in the GC development. METHODS: To evaluate barrier function of background mucosa against the stimulations, we applied biopsy samples from 76 patients with GC using a Ussing chamber system (UCs). K19-Wnt1/C2mE transgenic (Gan) mice and human GC cell-lines ± THP1-derived macrophage was applied to investigate the role of Pg. lipopolysaccharide in inflammation-associated carcinogenesis. RESULTS: In the UCs, Pg. lipopolysaccharide reduced the impedance of metaplastic and inflamed mucosa with increases in mRNA expression of toll-like receptor (TLR) 2, tumor necrosis factor (TNF) α, and apoptotic markers. In vitro, Pg. lipopolysaccharide promoted reactive oxidative stress (ROS)-related apoptosis as well as activated TLR2-ß-catenin-signaling on MKN7, and it increased the TNFα production on macrophages, respectively. TNFα alone activated TLR2-ß-catenin-signaling in MKN7, while it further increased ROS and TNFα in macrophages. Under coculture with macrophages isolated after stimulation with Pg. lipopolysaccharide, ß-catenin-signaling in MKN7 was activated with an increase in supernatant TNFα concentration, both of which were decreased by adding a TNFα neutralization antibody into the supernatant. In Gan mice with 15-week oral administration of Pg. lipopolysaccharide, tumor enlargement with ß-catenin-signaling activation were observed with an increase in TNFα with macrophage infiltration. CONCLUSIONS: Local exposure of Pg. lipopolysaccharide may increase ROS on premalignant gastric mucosa to induce apoptosis-associated barrier dysfunction and to secrete TNFα from activated macrophages, and both stimulation of Pg. lipopolysaccharide and TNFα might activate TLR2-ß-catenin-signaling in GC.

A case of refractory esophageal stricture due to occult gastrinoma of the duodenum.

Gastrinoma may cause refractory esophageal stricture due to gastro-esophageal reflux disease (GERD), but imaging technologies have limited power in its diagnosis. A 74-year-old female with a history of peptic ulcers suffered from repeated epigastralgia, and she visited a local hospital. An esophago-gastro-duodenoscopy (EGD) demonstrated severe reflux esophagitis and multiple peptic ulcers. Blood examination revealed a high value of fasting serum gastrin. Multi-detector computed tomography showed a hypervascular and tiny nodule in duodenal bulb, although other imaging technologies did not. Short-term medication with a proton pump inhibitor or potassium-competitive acid blocker was intermittently provided, but dysphagia was repeatedly worsened, and she was referred to our division. Serum hypergastrinemia was retained, and EGD reexamination depicted esophageal stricture, treated by multiple sessions of endoscopic balloon dilatation. Primary tumor was not identified by the morphological imaging technologies, but a selective arterial secretagogue injection test suggested its existence in the duodenum or pancreatic head. Pancreaticoduodenectomy was performed, and histological study identified 2 mm-sized microgastrinoma buried in Brunner`s glands on the posterior wall of the duodenum bulb. We reported a case with difficulty in diagnosis of the smallest sporadic gastrinoma of the duodenum, which might cause refractory GERD-associated stricture.

The relationship between plant-eating and hair evacuation in snow leopards (Panthera uncia).

Although most felids have an exclusive carnivore diet, the presence of plant matter in scat has been reported among various species. This indicates that there may be an adaptive significance to the conservation of plant-eating behavior in felid evolution. Some studies have hypothesized that felids consume plants for self-medication or as a source of nutrition. In addition, it is thought that plant intake helps them to excrete hairballs, however, no scientific work has confirmed these effects. Thus, the objective of this study is to investigate the relationship between plant intake and hair evacuation in felid species. We selected snow leopards (Panthera uncia) as the study species because they have longer and denser hair than other felids. The behavior of 11 captive snow leopards was observed and scat samples from eight of them and two other captive individuals were analyzed. Snow leopards evacuate hair possibly by vomiting and excreting in scats. The frequency of plant-eating and vomiting and the amount of hair and plant in scat were evaluated. We found that the frequency of vomiting was much lower than the frequency of plant-eating. In addition, there was no significant relationship between the amount of plant matter contained in scats and the amount of hair in scats. Contrary to the common assumption, our results indicate that plant intake has little effect on hair evacuation in felid species.