MicroRNA expression profile of human periodontal ligament cells under the influence of Porphyromonas gingivalis LPS

Periodontitis is a chronic inflammatory disease which is caused by bacterial infection and leads to the destruction of periodontal tissues and resorption of alveolar bone. Thus, special attention should be paid to the mechanism under lipopolysaccharide (LPS)‐induced periodontitis because LPS is the major cause of periodontitis. However, to date, miRNA expression in the LPS‐induced periodontitis has not been well characterized. In this study, we investigated miRNA expression patterns in LPS‐treated periodontal ligament cells (PDLCs). Through miRNA array and differential analysis, 22 up‐regulated miRNAs and 28 down‐regulated miRNAs in LPS‐treated PDLCs were identified. Seven randomly selected up‐regulated (miR‐21‐5p, 498, 548a‐5p) and down‐regulated (miR‐495‐3p, 539‐5p, 34c‐3p and 7a‐2‐3p) miRNAs were examined by qRT‐PCR, and the results proved the accuracy of the miRNA array. Moreover, targets of these deregulated miRNAs were analysed using the miRWalk database. Database for Annotation, Visualization and Integration Discovery software were performed to analyse the Gene Ontology and Kyoto Encyclopaedia of Genes and Genomes pathway of differential expression miRNAs, and the results shown that Toll‐like receptor signalling pathway, cAMP signalling pathway, transforming growth factor‐beta signalling pathway, mitogen‐activated protein kinase (MAPK) signalling pathway and other pathways were involved in the molecular mechanisms underlying LPS‐induced periodontitis. In conclusion, this study provides clues for enhancing our understanding of the mechanisms and roles of miRNAs as key regulators of LPS‐induced periodontitis.     

Changes in serum inflammatory factor interleukin-6 levels and pathology of carotid vessel walls of rats with chronic periodontitis and diabetes mellitus after the periodontal intervention

ObjectiveThe effects of the periodontal intervention on rats with type-II diabetes mellitus (T2DM) and chronic periodontitis (CP) were explored through observing the changes in carotid artery pathology and interleukin-6 (IL-6) levels.MethodsThe rats were randomly divided into 5 groups, i.e. group A (the normal control group), group B (the T2DM control group), group C (the CP control group), group D (the T2DM + CP group), and group E (the periodontal intervention T2DM + CP group). Blood samples of rats were collected from angular veins respectively at the following 5 time nodes: 1 week before the intervention (T1), 1 week after the intervention (T2), 3 weeks after the intervention (T3), 5 weeks after the intervention (T4), and 7 weeks after the intervention (T5); IL-6 concentrations before and after the intervention were determined by the enzyme-linked immunosorbent assay (ELISA), and the pathology of carotid arteries were observed by the Hematoxylin-Eosin (HE) stain.ResultsThe pathological results of carotid arteries showed that the blood vessels of rats in group A were normal in morphology; most of the carotid artery vessel walls of rats in groups B, C, and D were significantly thickened and the fibers were disorderly arranged; the increased thickness of vessel walls of rats in group E was reduced, a small number of foam cells and inflammatory cells were observed, and the irregular arrangement of fibers was improved. In terms of the IL-6 concentrations, during the period of T1-T5, in groups B, C, and D, the IL-6 concentrations in rats were increased (P < 0.05); after the periodontal intervention, in group E, the IL-6 concentrations in rats were first increased then decreased (P < 0.05).ConclusionIn terms of the long-term effects, periodontal intervention may reduce the inflammations of patients with diabetes mellitus and periodontitis and improve the lesions of carotid arteries.     

A novel phosphoglycerol serine-glycine lipodipeptide of Porphyromonas gingivalis is a TLR2 ligand

Porphyromonas gingivalis is a Gram-negative anaerobic periodontal microorganism strongly associated with tissue-destructive processes in human periodontitis. Following oral infection with P. gingivalis, the periodontal bone loss in mice is reported to require the engagement of Toll-like receptor 2 (TLR2). Serine-glycine lipodipeptide or glycine aminolipid classes of P. gingivalis engage human and mouse TLR2, but a novel lipid class reported here is considerably more potent in engaging TLR2 and the heterodimer receptor TLR2/TLR6. The novel lipid class, termed Lipid 1256, consists of a diacylated phosphoglycerol moiety linked to a serine-glycine lipodipeptide previously termed Lipid 654. Lipid 1256 is approximately 50-fold more potent in engaging TLR2 than the previously reported serine-glycine lipid classes. Lipid 1256 also stimulates cytokine secretory responses from peripheral blood monocytes and is recovered in selected oral and intestinal Bacteroidetes organisms. Therefore, these findings suggest that Lipid 1256 may be a microbial TLR2 ligand relevant to chronic periodontitis in humans.     

Transferrin receptor 2 mitigates periodontitis-driven alveolar bone loss

Periodontitis is associated with significant alveolar bone loss. Patients with iron overload suffer more frequently from periodontitis, however, the underlying mechanisms remain largely elusive. Here, we investigated the role of transferrin receptor 2 (Tfr2), one of the main regulators of iron homeostasis, in the pathogenesis of periodontitis and the dental phenotype under basal conditions in mice. As Tfr2 suppresses osteoclastogenesis, we hypothesized that deficiency of Tfr2 may exacerbate periodontitis-induced bone loss. Mice lacking Tfr2 (Tfr2^−/−) and wild-type (Tfr2^+/+) littermates were challenged with experimental periodontitis. Mandibles and maxillae were collected for microcomputed tomography and histology analyses. Osteoclast cultures from Tfr2^+/+ and Tfr2^−/− mice were established and analyzed for differentiation efficiency, by performing messenger RNA expression and protein signaling pathways. After 8 days, Tfr2-deficient mice revealed a more severe course of periodontitis paralleled by higher immune cell infiltration and a higher histological inflammation index than Tfr2^+/+ mice. Moreover, Tfr2-deficient mice lost more alveolar bone compared to Tfr2^+/+ littermates, an effect that was only partially iron-dependent. Histological analysis revealed a higher number of osteoclasts in the alveolar bone of Tfr2-deficient mice. In line, Tfr2-deficient osteoclastic differentiation ex vivo was faster and more efficient as reflected by a higher number of osteoclasts, a higher expression of osteoclast markers, and an increased resorptive activity. Mechanistically, Tfr2-deficient osteoclasts showed a higher p38-MAPK signaling and inhibition of p38-MAPK signaling in Tfr2-deficient cells reverted osteoclast formation to Tfr2^+/+ levels. Taken together, our data indicate that Tfr2 modulates the inflammatory response in periodontitis thereby mitigating effects on alveolar bone loss.     

龈沟液Chemerin、APN、25(OH)D3与伴2型糖尿病的慢性牙周炎患者牙周指标和Th17/Treg失衡的关系

摘要 目的：探讨龈沟液趋化素（Chemerin）、脂联素（APN）、25-羟维生素D3 [25(OH)D3]与伴2型糖尿病（T2DM）的慢性牙周炎（CP）患者牙周指标和Th17/Treg失衡的关系。方法：选择2021年1月至2022年1月我院口腔科门诊接诊的125例伴T2DM的CP患者,根据CP病情严重程度分为轻度组（42例）、中度组（53例）和重度组（30例）。检测龈沟液中Chemerin、APN、25(OH)D₃水平以及外周血中Th17细胞占比、Treg细胞占比,计算Th17/Treg比值,记录出血指数（SBI）、菌斑指数（PLI）、附着丧失（AL）、牙周袋探诊深度（PD）。分析龈沟液中Chemerin、APN、25(OH)D₃与牙周指标、外周血Th17/Treg的相关性。结果：重度组龈沟液 Chemerin水平和外周血中Th17细胞占比、Th17/Treg比值、PLI、SBI、AL、PD高于中度组和轻度组（P＜0.05）,龈沟液APN、25(OH)D₃水平,外周血Treg细胞占比低于中度组和轻度组（P＜0.05）。龈沟液 Chemerin与PLI、SBI、AL、PD、外周血Th17细胞占比、Th17/Treg比值呈正相关（P＜0.05）,与Treg细胞占比呈负相关（P＜0.05）;龈沟液APN、25(OH)D₃与PLI、SBI、AL、PD、外周血中Th17细胞占比、Th17/Treg比值呈负相关（P＜0.05）,与Treg细胞占比呈正相关（P＜0.05）。结论：伴T2DM 的CP患者龈沟液中Chemerin水平增高,APN、25(OH)D₃水平降低,且与牙周指标和Th17/Treg失衡有关。     

Development of tetracycline-serratiopeptidase-containing periodontal gel: Formulation and preliminary clinical study

The purpose of this research was to reduce the polymer concentration and to obtain reasonable viscosity at a lower concentration of pluronic by the addition of a viscosity modifier. A 20% wt/wt pluronic gel was prepared on a weight basis using the cold method. The effect of the amount of tetracycline and Aerosil on gel properties was studied. The gel was evaluated using different parameters: polarizing microscopy, gelation, gel melting, bioadhesivity, viscosity, drug release, and stability of enzyme. An in vivo study was performed to evaluate the clinical efficiency of the liquid crystalline gel. Addition of Aerosil to the gel favored hexagonal phase formation. Viscosity and bioadhesivity increased with an increase in the concentration of Aerosil. Release of tetracycline was sustained as the concentration of Aerosil increased. Various clinical parameters confirmed the acceptability and efficiency of this gel system. Published: September 15, 2006     

Inflammation has synergistic effect with nicotine in periodontitis by up‐regulating the expression of α7 nAChR via phosphorylated GSK‐3β

Periodontitis is the leading cause of adult tooth loss, and those who smoke are at an increased risk of developing periodontitis. α7 nicotinic acetylcholine receptor (α7 nAChR) is proposed to mediate the potential synergistic effect of nicotine and inflammation in smoking‐related periodontitis. However, this has not been experimentally demonstrated. We isolated and cultured human periodontal ligament stem cells (PDLSCs) from healthy and inflamed tissues. PDLSCs were treated with either inflammatory factors or nicotine. We measured expression of genes that are associated with osteogenic differentiation and osteoclast formation using RT‐qPCR and Western blot analyses. Besides, immunohistochemical staining, micro‐CT analysis and tartaric acid phosphatase staining were used to measure α7 nAChR expression and function. Inflammation up‐regulated α7 nAChR expression in both periodontal ligament tissues and PDLSCs. The up‐regulated α7 nAChR contributed to the synergistic effect of nicotine and inflammation, leading to a decreased capability of osteogenic differentiation and increased capability of osteoclast formation‐induction of PDLSCs. Moreover, the inflammation‐induced up‐regulation of α7 nAChR was partially dependent on the level of phosphorylated GSK‐3β. This study provides experimental evidence for the pathological development of smoking‐related periodontitis and sheds new light on developing inflammation and α7 nAChR‐targeted therapeutics to treat and prevent the disease.     

口炎清颗粒对慢性牙周炎患者牙周症状及炎性细胞因子水平的影响

目的:探讨口炎清颗粒对慢性牙周炎患者牙周症状及炎性细胞因子水平的影响。方法:选取我院2017年3月～2019年3月间收治的94例慢性牙周炎患者作为研究对象,按随机数字表法将患者分为对照组(n=47)和观察组(n=47)。对照组给予常规治疗,观察组在常规治疗基础上联合口炎清颗粒治疗,两组均治疗1个月。治疗后评价两组疗效,观察两组治疗过程中出现的不良反应。检测所有患者治疗前后的牙龈指数(GI)、菌斑指数(PLI)、牙周探诊深度(PD)、临床附着水平(CAL),以及龈沟液中的白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)以及白细胞介素-17(IL-17)水平。结果:观察组总有效率为93.62%,高于对照组的82.98%(P0.05)。两组不良反应发生率比较无统计学差异(P0.05)。治疗后,两组GI、PLI、PD、CAL均明显降低,且观察组GI、PLI、PD、CAL明显低于对照组,差异均具有统计学意义(P0.05)。治疗后,两组IL-1β、IL-6、IL-17水平均明显降低,且观察组IL-1β、IL-6、IL-17水平明显低于对照组,差异均具有统计学意义(P0.05)。结论:口炎清颗粒治疗慢性牙周炎疗效确切,能明显改善牙周症状,降低炎性细胞因子水平,且安全性良好。     

Periodontal therapy increases neutrophil extracellular trap degradation

In periodontitis, polymorphonuclear leucocytes (PMNs) are activated. They entrap and eliminate pathogens by releasing neutrophil extracellular traps (NETs). Abnormal NET degradation is part of a pro-inflammatory status, affecting co-morbidities such as cardiovascular disease. We aimed to investigate the ex vivo NET degradation capacity of plasma from periodontitis patients compared to controls (part 1) and to quantify NET degradation before and after periodontal therapy (part 2). Fresh NETs were obtained by stimulating blood-derived PMNs with phorbol 12-myristate 13-acetate. Plasma samples from untreated periodontitis patients and controls were incubated for 3 h onto freshly generated NETs (part 1). Similarly, for part 2, NET degradation was studied for 91 patients before and 3, 6 and 12 mo after non-surgical periodontal therapy with and without adjunctive systemic antibiotics. Finally, NET degradation was fluorospectrometrically quantified. NET degradation levels did not differ between periodontitis patients and controls, irrespective of subject-related background characteristics. NET degradation significantly increased from 65.6 ± 1.7% before periodontal treatment to 75.7 ± 1.2% at 3 mo post periodontal therapy, and this improvement was maintained at 6 and 12 mo, irrespective of systemic usage of antibiotics. Improved NET degradation after periodontitis treatment is another systemic biomarker reflecting a decreased pro-inflammatory status, which also contributes to an improved cardiovascular condition.