Oral bacteria colonize and compete with gut microbiota in gnotobiotic mice

The oral microbiota is associated with oral diseases and digestive systemic diseases.Nevertheless,the causal relationship between them has not been completely elucidated,and colonisation of the gut by oral bacteria is not clear due to the limitations of existing research models.The aim of this study was to develop a human oral microbiota-associated (HOMA) mouse model and to investigate the ecological invasion into the gut.By transplanting human saliva into germ-free (GF) mice,a HOMA mouse model was first constructed.16S rRNA gene sequencing was used to reveal the biogeography of oral bacteria along the cephalocaudal axis of the digestive tract.In the HOMA mice,84.78% of the detected genus-level taxa were specific to the donor.Principal component analysis (PCA) revealed that the donor oral microbiota clustered with those of the HOMA mice and were distinct from those of specific pathogen-free (SPF) mice.In HOMA mice,OTU counts decreased from the stomach and small intestine to the distal gut.The distal gut was dominated by Streptococcus,Veillonella,Haemophilus,Fusobacterium,Trichococcus and Actinomyces.HOMA mice and human microbiota-associated (HMA) mice along with the GF mice were then cohoused.Microbial communities of cohoused mice clustered together and were significantly separated from those of HOMA mice and HMA mice.The Source Tracker analysis and network analysis revealed more significant ecological invasion from oral bacteria in the small intestines,compared to the distal gut,of cohoused mice.In conclusion,a HOMA mouse model was successfully established.By overcoming the physical and microbial barrier,oral bacteria colonised the gut and profiled the gut microbiota,especially in the small intestine.

Novel dental implant modifications with two-staged double benefits for preventing infection and promoting osseointegration in vivo and in vitro

Peri-implantitis are a major problem causing implant failure these days.Accordingly,anti-infection during the early stage and subsequent promotion of osseointegration are two main key factors to solve this issue.Micro-arc oxidation(MAO)treatment is a way to form an oxidation film on the surface of metallic materials.The method shows good osteogenic properties but weak antibacterial effect.Therefore,we developed combined strategies to combat severe peri-implantitis,which included the use of a novel compound,PD,comprising dendrimers poly(amidoamine)(PAMAM)loading dimethylaminododecyl methacrylate(DMADDM)as well as MAO treatment.Here,we explored the chemical properties of the novel compound PD,and proved that this compound was successfully synthesized,with the loading efficiency and encapsulation efficiency of 23.91%and 31.42%,respectively.We further report the two-stage double benefits capability of PD+MAO:(1)in the first stage,PD+MAO could decrease the adherence and development of biofilms by releasing DMADDM in the highly infected first stage after implant surgery both in vitro and in vivo;(2)in the second stage,PD+MAO indicated mighty anti-infection and osteoconductive characteristics in a rat model of peri-implantitis in vivo.This study first reports the two-staged,double benefits of PD+MAO,and demonstrates its potential in clinical applications for inhibiting peri-implantitis,especially in patients with severe infection risk.