Biology of tongue coating in different disease stages of RA and its value in disease progression.

OBJECTIVE: To assess and compare the composition of tongue coating microbiota among patients at different stages of rheumatoid arthritis (RA). METHODS: A total of 47 patients diagnosed with RA, as per the American College of Rheumatology criteria, and 10 healthy individuals were enrolled in this study. The RA patients were stratified considering their Disease Activity Score 28 (DAS28), a composite measure based on the 28 tender and swollen joint count and erythrocyte sedimentation rate (ESR). The study population was further categorized into active phase group (LMH group) and inactive phase group (RE group) according to their DAS28 values. DNA extraction was extracted from tongue coating samples. Subsequently, the V3-V4 16S rDNA region was selectively amplified and sequenced through high-throughput 16S rDNA analysis. The resulting data were then utilized to ascertain the microbial contents. RESULTS: Significant variations were observed in the tongue coating microbiota of patients with RA during active and inactive phases, in comparison to healthy individuals (p < 0.05). At the genus level, the presence of Prevotellan, Veillonella, Rothia, and Neisseria in RA patients was notably more evident than in the healthy control (HC) group. These disparities find support in existing research on gut and oral microbiota. During the active phase of RA, the relative abundance of Veillonella, Rothia, and Neisseria in the tongue coating microbiota of patients was significantly higher than in those with inactive RA. These findings underscore the need for further and in-depth research on the potential impact of these microorganisms on the progression of RA disease. CONCLUSION: The results substantiate the hypothesis that tongue coating microbes actively contribute to the progression of RA.

Protective effect of Enterococcus faecium against ethanol-induced gastric injury via extracellular vesicles.

Recently, Enterococcus has been shown to have gastric protective functions, and the mechanisms by which Enterococcus modulates gastric function are still being investigated. Herein, we investigated how Enterococcus faecium (Efm) and E. faecium-derived extracellular vesicles (EVs) (EfmEVs) exert protective effect against ethanol-induced gastric injury by investigating the effect of EfmEVs on gastric mucosal ulcer scoring, histological lesion, mucosal glycoprotein production, acidity, anti-oxidative function, and inflammatory responses in rat. Pretreatment with Efm showed significant reduction of ethanol-induced gastric injury, as evidenced by the lowering of ulcer index, histological lesion, gastric pH, and inflammatory responses and the enhancement of mucosal glycoprotein production and anti-oxidative function. Further functional studies on three bioactive components [inactivated Efm, EfmEVs (EVs), and EV-free supernatants] of the bacterial culture showed that EVs are mostly responsible for the gastroprotective effect. Moreover, EV secretion is beneficial for the gastroprotective effect of Efm. Hence, EVs mediated the protective effect of Efm against ethanol-induced gastric injury by lowering inflammatory responses and enhancing anti-oxidative function and may be a potent anti-inflammatory and anti-oxidative strategy to alleviate hyperinflammatory gastrointestinal tract conditions.IMPORTANCEThis study indicated that Enterococcus faecium provided a protective effect against rat gastric injury, which involved improvement of the mucosal glycoprotein production, anti-oxidative function, and inflammatory responses. Furthermore, we confirmed that three bioactive components (inactivated Efm, extracellular vesicles, and EV-free supernatants) of E. faecium culture also contributed to the gastroprotective effect. Importantly, E. faecium-derived EVs showed an effective impact for the gastroprotective effect.

Effects of Salmonella Outer Membrane Vesicles on Intestinal Microbiota and Intestinal Barrier Function.

Salmonella enterica is one of the most important zoonotic pathogens causing foodborne gastroenteritis worldwide. Outer membrane vesicles (OMVs) are lipid-bilayer vesicles produced by Gram-negative bacteria, which contain biologically active components. We hypothesized that OMVs are an important weapon of S. enterica to initiate enteric diseases pathologies. In this study, the effects of S. enterica OMVs (SeOMVs) on intestinal microbiota and intestinal barrier function were investigated. In vitro fecal culture experiments showed that alpha diversity indexes and microbiota composition were altered by SeOMV supplementation. SeOMV supplementation showed an increase of pH, a decrease of OD630 and total short chain fatty acid (SCFA) concentrations. In vitro IPEC-J2 cells culture experiments showed that SeOMV supplementation did not affect the IPEC-J2 cell viability and the indicated genes expression. In vivo experiments in mice showed that SeOMVs had adverse effects on average daily gain (p < 0.05) and feed:gain ratio (p < 0.05), and had a tendency to decrease the final body weight (p = 0.073) in mice. SeOMV administration decreased serum interleukin-10 level (p < 0.05), decreased the relative abundance of bacteria belonging to the genera BacC-u-018 and Akkermansia (p < 0.05). Furthermore, SeOMV administration damaged the ileum mucosa (p < 0.05). These findings suggest that SeOMVs play an important role in the activation of intestinal inflammatory response induced by S. enterica, and downregulation of SCFA-producing bacteria is a possible mechanism.