Protective effect of Bacteroides fragilis LPS on Escherichia coli LPS-induced inflammatory changes in human monocytic cells and in a rheumatoid arthritis mouse model.

It has been reported that patients with rheumatoid arthritis (RA) have significantly less bacteria belonging to the Bacteroides group in their microbiota. We speculate that inhibition of cytokine production is impaired in patients with RA owing to their low levels of intestinal bacteria belonging to the Bacteroidetes group. Here we investigated the effect of Bacteroides fragilis lipopolysaccharide (B-LPS) on cytokine production in vitro and on the development of collagen antibody-induced arthritis (CAIA) in DBA/1 mice, an animal model of RA. in vitro culture experiments showed that Escherichia coli LPS (E-LPS)-induced cytokine production from THP-1 monocytic cells and peripheral blood mononuclear cells was significantly suppressed by B-LPS in a dose-dependent manner. A decrease in TNF-α and IL-1ß production was also observed in LPS-tolerized macrophages induced by B-LPS at concentrations equal to and higher than that of E-LPS. Similar results were obtained when autoclaved feces were used to induce cytokine production instead of E-LPS. In in vivo experiments using CAIA models, B-LPS had no adverse effects even when administered at 10 times the concentration of E-LPS, which elicits severe arthritis. In addition, simultaneous administration of high dose B-LPS with E-LPS or administration of B-LPS prior to E-LPS significantly suppressed arthritis development in CAIA model animals when compared with administration of E-LPS alone. These results suggest that increasing certain bacterial groups such as Bacteroides is an effective strategy for preventing arthritis development in patients with RA.

Usefulness of the newly developed artificial denture plaque for practical denture care training.

OBJECTIVES: The aim of this study was to investigate whether the newly developed artificial dental plaque (A-DP) is useful as an educational tool for denture care of dental hygienist that compared it with conventional artificial dental plaque from the viewpoint of practical skills. MATERIAL AND METHODS: The 125 dental hygienist school students and 26 dental hygienists who had clinical experience were subjected a practical training of denture plaque control using the conventional denture plaque (C-DP) and the A-DP. The questionnaires based on the semantic differential method were used to survey whether the A-DP is similar to the real denture plaque (R-DP). Factor analysis by rotation of promax was carried out. RESULTS: In the results of the factor analysis, the two factors could be detected in students and three factors in dental hygienists. The total score of each denture plaque was calculated for each factor, and correlation coefficient was examined. There was significant correlation between the A-DP and the R-DP at the first factors, both students and dental hygienists. C-DP was not similar to R-DP in all factors. CONCLUSIONS: These results suggested that A-DP resembles R-DP better than C-DP. It was concluded that the A-DP was similar to the R-DP and could be a potent educational tool for practical denture care.

Terminalia bellirica (Gaertn.) Roxb. Extract and Gallic Acid Attenuate LPS-Induced Inflammation and Oxidative Stress via MAPK/NF-κB and Akt/AMPK/Nrf2 Pathways.

Excessive oxidative stress plays a critical role in the progression of various diseases. Recently, we showed that Terminalia bellirica (Gaertn.) Roxb. extract (TBE) inhibits inflammatory response and reactive oxygen species (ROS) production in THP-1 macrophages. However, molecular mechanisms underlying anti-inflammatory and antioxidant activities of TBE and its major polyphenolic compounds gallic acid (GA) and ellagic acid (EA) remain unclear. We found that TBE and GA attenuated LPS-induced inflammatory mediator expression, ROS production, and activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) in RAW 264 macrophages. Furthermore, TBE and GA increased antioxidant enzyme expression along with upstream mediators nuclear factor erythroid-2-related factor 2 (Nrf2), Akt, and AMP-activated protein kinase (AMPK). Importantly, knockdown of Nrf2 by siRNA and specific inhibition of Akt and AMPK significantly reduced antioxidant enzyme expression induced by TBE and GA. Finally, in vivo effects on histopathology and gene expression were assessed in tissues collected after intraperitoneal injection of LPS with or without TBE treatment. TBE enhanced antioxidant enzyme expression and improved acute kidney injury in LPS-shock model mice. In conclusion, TBE and GA exert protective effects against inflammation and oxidative stress by suppressing MAPK/NF-κB pathway and by activating Akt/AMPK/Nrf2 pathway. These results suggest that TBE and GA might be effective for the treatment of inflammation-related diseases.