Ecological shifts of salivary microbiota associated with metabolic-associated fatty liver disease.

Introduction: Metabolic-associated fatty liver disease (MAFLD) is the most common chronic liver disease related to metabolic syndrome. However, ecological shifts in the saliva microbiome in patients with MAFLD remain unknown. This study aimed to investigate the changes to the salivary microbial community in patients with MAFLD and explore the potential function of microbiota. Methods: Salivary microbiomes from ten MAFLD patients and ten healthy participants were analyzed by 16S rRNA amplicon sequencing and bioinformatics analysis. Body composition, plasma enzymes, hormones, and blood lipid profiles were assessed with physical examinations and laboratory tests. Results: The salivary microbiome of MAFLD patients was characterized by increased α-diversity and distinct ß-diversity clustering compared with control subjects. Linear discriminant analysis effect size analysis showed a total of 44 taxa significantly differed between the two groups. Genera Neisseria, Filifactor, and Capnocytophaga were identified as differentially enriched genera for comparison of the two groups. Co-occurrence networks suggested that the salivary microbiota from MAFLD patients exhibited more intricate and robust interrelationships. The diagnostic model based on the salivary microbiome achieved a good diagnostic power with an area under the curve of 0.82(95% CI: 0.61-1). Redundancy analysis and spearman correlation analysis revealed that clinical variables related to insulin resistance and obesity were strongly associated with the microbial community. Metagenomic predictions based on Phylogenetic Investigation of Communities by Reconstruction of Unobserved States revealed that pathways related to metabolism were more prevalent in the two groups. Conclusions: Patients with MAFLD manifested ecological shifts in the salivary microbiome, and the saliva microbiome-based diagnostic model provides a promising approach for auxiliary MAFLD diagnosis.

[Developments in Research on the Relationship Between Porphyromonas gingivalis and Non-Oral Diseases].

Porphyromonas gingivalis ( P. gingivalis) is a common periodontal pathogen. Recently, there has been increasing evidence suggesting that P. gingivalis is not only a common pathogen in the oral cavity, but is also closely associated with non-oral diseases, including inflammatory bowel disease, cancer, cardiovascular diseases, Alzheimer's disease, rheumatoid arthritis, diabetes mellitus, premature birth and non-alcoholic hepatitis, etc. Herein, we reviewed the developments in recent years in research on the relationship between P. gingivalis, a periodontal pathogen, and non-oral diseases, which will help determine whether P. gingivalis could be used as an auxiliary diagnostic biomarker or a potential therapeutic target for these non-oral diseases, thus contributing to the development of treatment strategies for the relevant diseases.

[Accuracy of 3D reconstruction of pulp cavity in mandibular premolars based on cone-beam CT].

PURPOSE: To analyze the accuracy of 3D reconstruction of pulp cavity in mandibular premolars based on cone-beam CT (CBCT). METHODS: Thirty-two extracted single-rooted mandibular premolars were randomly collected and scanned by micro-CT and CBCT. After image segmentation and 3D reconstruction, the surface model and volume model of the pulp cavity were rendered. By using Amira 5.0 software, each pairs of pulp cavity surface models were registered. The surface models reconstructed from micro-CT scanning were set as the references and the surface models reconstructed from CBCT were tested. The morphological differences between each pairs of surface models were calculated by Amira 5.0 software and represented by color-coded maps. The total 3D morphological difference value of each sample was recorded and the volume reconstruction differences between the two image acquisition techniques were analyzed. Statistical analysis was performed with SPSS 13.0 software package. RESULTS: The mean value of 3D morphological differences of 32 teeth was 0.27 mm. Distribution of the greatest morphological differences were mainly located in the apical portion of the pulp cavity and some small anatomical variation. The volume of the reconstructed models by micro-CT and CBCT were (34.89±4.36) mm3 and (27.32±4.83) mm3 respectively, and the difference was significant (P＜0.05). CONCLUSIONS: When CBCT scanning is used to reconstruct pulp cavity of mandibular premolars, there is certain degree of information loss, which mainly distributes in the apical portion and small anatomical variation sites. Dentists should consider these characteristics during clinical application of CBCT.

[Temporal and spacial expression of LIM mineralization protein 1 during rat pulp injury and reparation].

PURPOSE: To investigate the expression and localization of LIM mineralization protein 1(LMP-1) during rat pulp injury and reparation. METHODS: Dental pulp injury models were established in maxillary first molars on one side of 12 Wistar rats, the isonym healthy teeth on the opposite side were used as the controls. Immunohistochemistry technique was used to observe the expression of LMP-1 at 1, 3 and 7 day after pulp injury. The results of staining were analyzed by Image-Pro Plus 6.0 and SPSS 17.0 software package. RESULTS: LMP-1 was not detected in normal rat dental pulp. Positive staining of LMP-1 was found in odontoblasts and some dental pulp cells at 1 day after pulp injury. The expression of LMP-1 was converged at cell proliferation zone under the injury site at 3 and 7 day after injury. CONCLUSIONS: LMP-1 might play a role in the dental pulp cell proliferation and differentiation and reparative dentin formation during pulp injury and reparation.

[Temporal and spacial expression of perlecan in dental pulp after injury].

PURPOSE: To investigate the temporal and special expressions and functions of perlecan in dental pulp of rats after injury. METHODS: Specimens of one side of maxillary molars of 24 male SD rats were collected 1,3,5,7 days after injury, and the other side were used as controls. The specimens were decalcified and embedded in paraffin, sliced by longitudinal section and stained by immunohistochemistry. The staining of perlecan and ß1 integrin were examined, and the average optical density (AOD) was compared. The measurement data were analyzed by ANOVA using SPSS 19.0 software package. RESULTS: The staining intensity of perlecan in dental pulp in the experimental group was significantly higher compared with that of the control group. The immunolocalization of perlecan in dental pulp was gradually progressed as the inflamed tissue was progressing after injury, and its AOD was significantly higher than that of control group (F=11.104,P>0.05), especially in the group of 1 d. The staining of ß1 integrin was generally enhanced in the pulp 3 d after injury, and its AOD was significantly higher than that of control group (F=124.18,P>0.05). CONCLUSIONS: Perlecan may play an important role in tissue defense mechanism after injury through regulating angiogenesis and inflammatory cell infiltration. Supported by Science and Technology Research Project of Department of Education of Zhejiang Province (20051196) and Wenzhou City (Y20100015).

[An anticaries experimental study of SD rat immunized by recombinant plasmid pEGFP-N1-Srv+ encoding the V-region of surface protein of Streptococcus mutans].

PURPOSE: An anticaries DNA vaccine pEGFP-N1-Srv+ was used to immunize rats by different immune pathways. The expression of recombinant plasmid in different tissues in vivo and the specific immune response and protection effects against dental caries were observed. METHODS: 20 SD rats were divided into 4 groups, immunized with the recombinant plasmid pEGFP-N1-SrV+ by submandibular gland-target injection(TSG), and intramuscular injection,respectively; then the expression of recombinant plasmid in different tissues were detected by immunohistochemistry technique. 24 SD rats were divided into 4 groups, immunized with recombinant plasmid pEGFP-N1-SrV+ of 100 µg, then boosted once after two weeks, through the same routes as above;then indirect ELISA technique was used to detect the specific antibodies. Keyes caries scores were used to evaluate the anticaries effects. The data was analyzed by using SPSS17.0 software package. RESULTS: (1)Recombinant plasmid was positively expressed in the muscle fibers and submandibular glands.(2)The specific salivary anti-SR IgA and serum IgG were detected, and the peak time of the antibodies level appeared 4 weeks after initial . At the 4th week, the levels of specific anti-SR antibodies were higher in the experimental group than that in the negative control group. The levels of salivary specific anti-SR IgA were significantly higher in TSG immunization group than that in the intramuscular injection group. (3)Keyes caries scores were not significantly different between the experimental groups and negative control groups. recombinant plasmid pEGFP-N1-Srv+ expressed in vivo and effectively increased specific salivary anti-SR IgA and serum IgG, and TSG immunization route significantly increased the specific salivary anti-SR IgA compared with the intramuscular immunization route;however, the recombinant plasmid pEGFP-N1-Srv+ alone can not protect the rats from dental caries. CONCLUSIONS: The recombinant plasmid pEGFP-N1-SrV+ expressed in vivo and effectively increased specific salivary anti-SR IgA and serum IgC, and TSG immunization route significantly increased the specific salivary anti-SR IgA compared with the intramuscular immunization route; however, the recombinant plasmid pEGFP-N1-Srv+ alone can not protect the rats from dental caries.

[Study on the genetic diversity within the extended-V region of the surface protein of Streptococcus mutans].

PURPOSE: The purpose of this study was to investigate the genicity of the extended- variable region (V+) of surface proteins of Streptococcus mutans (S. mutans, serotype c,f) and provide some genetic informations on the molecular structure of S. mutans surface protein. METHODS: 7 standard strains and 110 clinical isolates of S.mutans were selected.The bacterial DNA was extracted and the extended-V region (srV+ 1384-2514 bp) was amplified using polymerase chain reaction (PCR). The genetic diversity of srV+ was assessed by using restriction fragment length polymorphism (RFLP) with restriction endonuclease DdeI. RESULTS: The results showed that five different patterns (A,B,C,D,E) of the PCR-RFLP among the 117 strains were reveled by DdeI. The ration of the genotype A and B were the most among the strains, C followed by genotype, the D and E were 1 and 3 strains per genotype, respectively.OMZ175 (serotype f) belonged to B genotype. CONCLUSIONS: The study supported that the extended-variable region (srV+) of the surface proteins of Streptococcus mutans have diversity. There are five patterns of genotypings. The most genotypings were p1-like,spaP /sr-like and pac-like.