Role of CD86 on granulocyte in mediating the effect of Genus Roseburia on periodontitis.

OBJECTIVES: This study aimed to explore the causal link between the gut microbiota and periodontitis, and to delineate and quantify the intermediary role of immune cells, so as to provide new insights into the pathogenesis, prevention and treatment of periodontitis. MATERIALS AND METHODS: We employed a two-sample Mendelian randomization (MR) approach to analyze the genetic predictors of gut microbiota composition (covering 412 gut microbiota taxa and functions) and periodontitis (involving 4,784 cases and 272,252 controls) derived from genome-wide association study (GWAS) datasets. A subsequent two-step MR analysis was conducted to evaluate the extent to which immune cell traits (encompassing 731 immune cell characteristics) mediate the influence of gut microbiota on periodontitis risk. RESULTS: Our analysis implicated nine gut microbiota taxa as causal factors in periodontitis susceptibility (p < 0.05). Notably, the Genus Roseburia was identified as exerting a protective effect against periodontitis, partially mediated through the upregulation of CD86 expression on granulocytes, with an 8.15% mediation effect observed. CONCLUSIONS: Our findings establish a causal relationship between the gut microbiota and periodontitis, highlighting the protective role of Roseburia against this condition. A notable proportion of this protective effect is mediated via the upregulation of CD86 on granulocytes. CLINICAL RELEVANCE: It can provide new ideas for the pathogenesis, prevention and treatment for periodontitis through exploring the causal link between the gut microbiota and periodontitis, and describing and quantifying the intermediary role of immune cells.

Distraction osteogenesis after irradiation in rabbit mandibles.

The aim of this study was to investigate the influence of irradiation on the formation of bone after distraction osteogenesis in rabbit mandibles. Sixteen rabbits were randomly divided into 3 groups: one was given 50Gy (n=6), one was given 60Gy (n=6), and one acted as a control group (n=4). One month after irradiation, the distractors were inserted. The control group was not irradiated. After a latency period of 8 days, distraction was activated at a rate of 0.4mm twice a day. The mandibles were harvested 6 weeks after consolidation. The specimens and histological examination showed good formation of bone. Histological slides stained with haematoxylin and eosin confirmed that the regeneration was bone. The bony trabeculae of the control group were much better than those of the irradiated groups. However, the nuclei of osteocytes were round and the osteoblasts around the trabeculae were columnar or cubic in shape in the irradiated groups. Osteoid was present in the dense fibrous connective tissue. There were significant differences in the surface:volume ratio of areas of bony trabeculae between the control and both experimental groups (p=0.010 and p=0.001), but there was no significant difference between the 50Gy and 60Gy groups. The results suggested that preoperative radiation prevented optimal regeneration of bone. However, the microscopic appearance of osteocytes and osteoblasts and the osteoid in the dense fibrous connective tissue in both irradiated groups showed that osteogenesis was still active and in progress. These findings may indicate that bone formation had only been delayed. The evidence was similar for both 50Gy and 60Gy.

[Experimental study on the reconstruction of mandibular symphyseal defects by internal tri-focal distractor].

OBJECTIVE: To introduce the internal tri-focal distractor developed by the authors and evaluate its primary application and feasibility in animal experiment. METHODS: Four hybrid dogs were selected and segmental resection at the mandibular symphysis was performed. Two transfer disks, 10 mm in width, were respectively fixed at the two ends of bone defect and the internal tri-focal distractor was installed. The force was applied one week after the operation, with a tractive speed of 0.5 mm/12 h. After 13 - 16 days, the traction was completed when the two transfer disks were combined. The occlusal films were taken at the 1st day, 4th, 8th and 12th week after traction. The animals were killed at the 12th week, samples of the traction area taken and histological examination performed. Finally, the new bone formation was observed. RESULTS: All the animals survived in the experiment, abruption and rust-eaten was not found in distractor. In the 12th week after installation, new bones in traction gap were mature and bony union between the two transfer dishes was accomplished. CONCLUSIONS: The internal tri-focal distractor used in this study may become a potential device in reconstruction of mandibular symphyseal defects.

[Distraction osteogenesis for treatment of unilateral temporomandibular joint ankylosis and secondary OSAHS in children: report of 4 cases].

PURPOSE: To evaluate the efficiency of distraction osteogenensis for treatment of unilateral temporomandibular joint ankylosis and secondary OSAHS in children. METHODS: 4 children with temporomandibular joint ankylosis and secondary OSAHS were retrospectively reviewed for their treatment. There were 2 males and 2 females, ranging from 5 to 13 years in age with the median of 6.5 years. Based on the history of the disease, the clinical manifestations, CT scan and PSG findings, the diagnosis was confirmed to be unilateral temporomandibular joint ankylosis and secondary OSAHS. All the patients were treated by gap arthroplasty to restore mouth opening, combined with mandibular body distraction osteogenesis for treatment of OSAHS. One-stage operation was performed on 3 patients, and two-stage operation on 1 patient. Unilateral and bilateral mandibular distraction osteogenesis was undergone on 2 patients individually. At the end of consolidation period of 3 months, the PSG examination was performed again and the distractor was removed. RESULTS: OSAHS was cured, the average AHI was lowered from 42.7 to 4.9, the average lowest saturation of blood oxygen rose from 74.3% to 89.8%, the average incisor distance reached 25.5mm compared to 6.5mm before surgery and facial deformity was corrected satisfactorily. Following up 38.1 months (13-58 months), no relapse appeared. CONCLUSION: Mandibular body distraction osteogenesis, combined with gap arthroplasty, could be the potential treatment modality for children with unilateral temporomandibular joint ankylosis, secondary OSAHS and facial asymmetry; it is recommended that both procedures be performed at the same time.