MSC-derived exosomes protect auditory hair cells from neomycin-induced damage via autophagy regulation

BACKGROUND: Sensorineural hearing loss (SNHL) poses a major threat to both physical and mental health; however, there is still a lack of effective drugs to treat the disease. Recently, novel biological therapies, such as mesenchymal stem cells (MSCs) and their products, namely, exosomes, are showing promising therapeutic potential due to their low immunogenicity, few ethical concerns, and easy accessibility. Nevertheless, the precise mechanisms underlying the therapeutic effects of MSC-derived exosomes remain unclear. RESULTS: Exosomes derived from MSCs reduced hearing and hair cell loss caused by neomycin-induced damage in models in vivo and in vitro. In addition, MSC-derived exosomes modulated autophagy in hair cells to exert a protective effect. Mechanistically, exogenously administered exosomes were internalized by hair cells and subsequently upregulated endocytic gene expression and endosome formation, ultimately leading to autophagy activation. This increased autophagic activity promoted cell survival, decreased the mitochondrial oxidative stress level and the apoptosis rate in hair cells, and ameliorated neomycin-induced ototoxicity. CONCLUSIONS: In summary, our findings reveal the otoprotective capacity of exogenous exosome-mediated autophagy activation in hair cells in an endocytosis-dependent manner, suggesting possibilities for deafness treatment.

Progress of research on diagnosis and treatment of the first bite syndrome / 口腔医学

@#The first bite syndrome is a rare maxillofacial pain syndrome easily ignored by clinicians. The pain caused by it not only makes it difficult for patients to eat and delays surgical wound healing, but also rises fear and anxiety of patients while they eat, which would severely reduce their life quality. There are few case reports about the first bite syndrome in China, and clinicians know little about it. Therefore, the early diagnosis and treatment of such a disease are important. In this review, we thoroughly reviewed the etiology and classification, pathogenesis, clinical manifestation, and current treatments of the first bite syndrome, aiming at providing some suggestions for clinicians.

Effects of different debridement methods on titanium surfaces in vitro / 口腔疾病防治

Objective @#To investigate the effect of different decontamination methods, including photodynamic therapy, sandblasting and titanium curette, on titanium surface morphology and bacterial adhesion for the treatment of peri-implant disease. @*Methods@#Porphyromonas gingivalis (Pg) and Fusobacterium nucleatum (Fn) were inoculated on the surface of polished titanium specimens, and titanium specimen surfaces were treated with different decontamination methods after incubation. The titanium specimens were divided into a no-treatment control group, photodynamic group, sandblasting group and titanium curette group according to different decontamination methods. The changes in titanium surface roughness were observed by atomic force microscopy (AFM), and the remaining bacteria on the titanium surface were observed by scanning electron microscopy (SEM) and live/dead bacteria staining tests. After reinoculation of Pg and Fn, bacterial readhesion was observed on the surface of decontaminated titanium specimens. @*Results @#The AFM results showed that the surface roughness of the titanium curette group was significantly higher than that of the no-treatment control group, photodynamic group and sandblasting group (P<0.05), and there was no statistically significant difference between the no-treatment control group, photodynamic group and sandblasting group (P>0.05). The results of contact angle measurement showed that the surface contact angle of each treatment group was smaller than that of the no-treatment control group (P<0.05). The SEM results obtained after the titanium specimen surface was decontaminated showed that the number of bacteria on the no-treatment control group surface was higher and the bacteria were relatively concentrated. The bacteria on the surface of the photodynamic group, sandblasting group and titanium curette group were scattered and distributed in small numbers, and most bacteria on the surface of the photodynamic group were ruptured. The results of the live/dead bacteria staining experiment showed that the percentage of dead bacteria on the surface of the photodynamic group was significantly higher than that of the no-treatment control group, sandblasting group and titanium curette group (P<0.05). The remaining bacteria on the surface of the sandblasting group and titanium curette groups were mainly live bacteria. The remaining bacterial adhesion on the surface was significantly reduced for the sandblasting group compared to the no-treatment control group and the photodynamic and titanium curette groups (P<0.05). SEM and live/dead bacteria staining results of bacterial readhesion on the surface of titanium specimens showed that there was an aggregation of Pg on the surface of the titanium curette group, and its surface bacterial adhesion was significantly higher than that of the no-treatment control group, photodynamic group and sandblasting group. @*Conclusion @#In mechanical decontamination, sandblasting machines are a better option than photodynamic therapy and titanium curettes; however, sandblasting does not remove all bacterial contamination. For sterilization, photodynamic therapy is more effective than sandblasting and titanium curettes. A combination of sandblasting and photodynamic therapy methods for the treatment of peri-implant disease may be considered in clinical practice.