Effectiveness of typodont, quail egg and virtual simulation for ultrasonic periodontal scaling teaching among pre-clinical students: a randomized trial.

BACKGROUND: This study aimed to compare the efficacy of three different techniques, namely virtual simulation technology (VS), traditional pathological typodont (TT), and quail egg (QE), in pre-clinical training of periodontal ultrasonic scaling. It also aimed to propose an integrated teaching approach for ultrasonic scaling teaching. METHODS: This single-blind randomized multi-arm trial enrolled 108 fourth-year students from Guanghua School of Stomatology at Sun Yat-sen University. The participants were randomly, evenly assigned to VS, TT, or QE group. First, the participants received theoretical review on ultrasonic scaling and demonstrative teaching. Then in the 90-minute operation training by group, students used traditional typodont equipped in head-simulators, raw quail eggs, or scaling module of the UniDental VS system respectively. Then all participants practiced on pathological models for 30 min. In the final operation examination, participants were instructed to remove the supra- and sub-gingival calculi pre-set on designated teeth by ultrasonic scalers within 30 min. Their performances were evaluated by residual calculus rate and a multi-perspective scoring scale. After the examination, questionnaires were provided to assess the teaching effects of each method and the fidelity of VS. Statistical analysis was carried out using one-way, two-way ANOVA, and multiple t-test. RESULTS: Students in VS group had significant higher total test scores than QE group (87.89 ± 6.81, 83.53 ± 8.14) and TT group (85.03 ± 6.81). VS group scored higher in several dimensional comparisons with the other two groups, especially in difficult situations. QE group had higher scores particularly in force application and supra-gingival scaling. TT group scored the highest in pivot stability practice and body position training. Students gave higher scores when assessing the fidelity of VS than experienced teachers. CONCLUSION: The study highlights the importance of specialized pre-clinical training on ultrasonic scaling for dental students. The methods adopted in current study (VS, TT and QE) each offered unique advantages in education, which can be combined to create an integrative teaching procedure. This procedure aims to provide an effective, advisable and normative pre-clinical training procedure for ultrasonic scaling. By utilizing the strengths of each method, dental educators can deliver high-quality training and ensure that students are well-prepared for clinical practice.

Restoring periodontal tissue homoeostasis prevents cognitive decline by reducing the number of Serpina3nhigh astrocytes in the hippocampus.

Cognitive decline has been linked to periodontitis through an undetermined pathophysiological mechanism. This study aimed to explore the mechanism underlying periodontitis-related cognitive decline and identify therapeutic strategies for this condition. Using single-nucleus RNA sequencing we found that changes in astrocyte number, gene expression, and cell‒cell communication were associated with cognitive decline in mice with periodontitis. In addition, activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome was observed to decrease the phagocytic capability of macrophages and reprogram macrophages to a more proinflammatory state in the gingiva, thus aggravating periodontitis. To further investigate this finding, lipid-based nanoparticles carrying NLRP3 siRNA (NPsiNLRP3) were used to inhibit overactivation of the NLRP3 inflammasome in gingival macrophages, restoring the oral microbiome and reducing periodontal inflammation. Furthermore, gingival injection of NPsiNLRP3 reduced the number of Serpina3nhigh astrocytes in the hippocampus and prevented cognitive decline. This study provides a functional basis for the mechanism by which the destruction of periodontal tissues can worsen cognitive decline and identifies nanoparticle-mediated restoration of gingival macrophage function as a novel treatment for periodontitis-related cognitive decline.

Nisin lantibiotic prevents NAFLD liver steatosis and mitochondrial oxidative stress following periodontal disease by abrogating oral, gut and liver dysbiosis.

Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum, were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin's ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

High-Throughput Combined Analysis of Saliva Microbiota and Metabolomic Profile in Chinese Periodontitis Patients: A Pilot Study.

The onset and progression of periodontitis involves complicated interactions between the dysbiotic oral microbiota and disrupted host immune-inflammatory response, which can be mirrored by the changes in salivary metabolites profile. This pilot study sought to examine the saliva microbiome and metabolome in the Chinese population by the combined approach of 16s rRNA sequencing and high-throughput targeted metabolomics to discover potential cues for host-microbe metabolic interactions. Unstimulated whole saliva samples were collected from eighteen Stage III and IV periodontitis patients and thirteen healthy subjects. Full-mouth periodontal parameters were recorded. The taxonomic composition of microbiota was obtained by 16s rRNA sequencing, and the metabolites were identified and measured by ultra-high performance liquid chromatography and mass spectrometry-based metabolomic analysis. The oral microbiota composition displayed marked changes where the abundance of 93 microbial taxa differed significantly between the periodontitis and healthy group. Targeted metabolomics identified 103 differential metabolites between the patients and healthy individuals. Functional enrichment analysis demonstrated the upregulation of protein digestion and absorption, histidine metabolism, and nicotinate and nicotinamide metabolism pathways in the dysbiotic microbiota, while the ferroptosis, tryptophan metabolism, glutathione metabolism, and carbon metabolism pathways were upregulated in the patients. Correlation analysis confirmed positive relationships between the clinical parameters, pathogen abundances, and disease-related metabolite levels. The integral analysis of the saliva microbiome and metabolome yielded an accurate presentation of the dysbiotic oral microbiome and functional alterations in host-microbe metabolism. The microbial and metabolic profiling of the saliva could be a potential tool in the diagnosis, prognosis evaluation, and pathogenesis study of periodontitis.

The Application of Virtual Simulation Technology in Scaling and Root Planing Teaching.

BACKGROUND: Virtual simulation (VS) technology has been widely utilised in various aspects of oral education. This study aimed to evaluate the impact of VS technology in a scaling and root planing (SRP) teaching programme and explore an effective teaching approach. METHOD: A total of 98 fourth-year undergraduates from Guanghua School of Stomatology at Sun Yat-sen University were enrolled in this study and randomly assigned to either the VS teaching group or the traditional teaching (TT) group. All participants received SRP training before undergoing an operational examination. Subsequently, questionnaires were administered to both students and teachers involved in the programme to assess the teaching effect and fidelity of the VS training system. Unpaired Student t test was used to analyse the final test scores and residual rates amongst students. RESULTS: The overall residual rate of the calculus in the VS group was significantly lower than that in the TT group (48.81% ± 13.50% vs 56.89% ± 13.68%, P<.01). The difference was particularly notable in posterior teeth, proximal surfaces, and deep pockets. Additionally, the VS group students achieved higher final grades compared to the TT group (86.92 ± 6.10 vs 83.02 ± 6.05, P<0.01). In terms of teaching effectiveness assessment, the VS group students provided higher scores than the TT group, except in the areas of mastery of position, finger rests, and efficiency. CONCLUSIONS: The implementation of VS technology demonstrated improvements in students' performance in SRP teaching. Therefore, a novel integrated pedagogic approaches method that combines VS technology with traditional teaching approaches could be further explored in future training programmes.

The effect of virtual simulation technology applied to undergraduate teaching of periodontal probing.

INTRODUCTION: The rise of virtual simulation technology and dental simulators has created a new pedagogical approach for undergraduate medical education. The purpose of this study is to evaluate the effect of virtual simulation (VS) technology on improving the students' comprehensive abilities in periodontal probing teaching in pre-practicum periodontology, such as increasing the accuracy of probing, tactile perception and performance on force control. MATERIALS AND METHODS: Twenty students were randomly selected among the fourth-year students and equally divided into VS technology teaching group (VS group) and traditional teaching group (TT group) by drawing half lots. One day later, students were required to probe the periodontal pathology model. The consistency rate between PD measurements and PD reference values, time consumption and final exam scores were recorded and statistically analysed using an unpaired Student's t test and p < .05 was considered statistical significance. Finally, questionnaires relating to teaching methods evaluation and the fidelity of the digital VS training system were distributed to students and teachers. RESULTS: VS group had a significantly higher consistency rate (72.976 ± 6.811%) than TT group (64.107 ± 4.988%, p = .004). To specify, the difference of consistency rates between the two groups in posterior teeth was larger than anterior teeth. Similarly, a larger difference was also found in proximal surfaces compared with buccal-lingual surfaces. As the pocket depth increased, the difference between the two groups increased too. These results indicated that VS is more efficient in complicated parts of periodontal probing teaching. In addition, students in VS group spent less time and gained a higher score than TT group (p < .05). The overall satisfaction rating in VS group was significantly higher than TT group. Lastly, teachers gave significant lower scores than students concerning the fidelity of VS system. CONCLUSION: Although there are much to improve, VS technology has obvious advantages in periodontal probing teaching in pre-practicum periodontology.

Nisin a probiotic bacteriocin mitigates brain microbiome dysbiosis and Alzheimer's disease-like neuroinflammation triggered by periodontal disease.

INTRODUCTION: Periodontitis-related oral microbial dysbiosis is thought to contribute to Alzheimer's disease (AD) neuroinflammation and brain amyloid production. Since probiotics can modulate periodontitis/oral dysbiosis, this study examined the effects of a probiotic/lantibiotic, nisin, in modulating brain pathology triggered by periodontitis. METHODS: A polymicrobial mouse model of periodontal disease was used to evaluate the effects of this disease on brain microbiome dysbiosis, neuroinflammation, Alzheimer's-related changes, and nisin's therapeutic potential in this context. RESULTS: 16S sequencing and real-time PCR data revealed that Nisin treatment mitigated the changes in the brain microbiome composition, diversity, and community structure, and reduced the levels of periodontal pathogen DNA in the brain induced by periodontal disease. Nisin treatment significantly decreased the mRNA expression of pro-inflammatory cytokines (Interleukin-1ß/IL-1 ß, Interleukin 6/IL-6, and Tumor Necrosis Factor α/TNF-α) in the brain that were elevated by periodontal infection. In addition, the concentrations of amyloid-ß 42 (Aß42), total Tau, and Tau (pS199) (445.69 ± 120.03, 1420.85 ± 331.40, 137.20 ± 36.01) were significantly higher in the infection group compared to the control group (193.01 ± 31.82, 384.27 ± 363.93, 6.09 ± 10.85), respectively. Nisin treatment markedly reduced the Aß42 (261.80 ± 52.50), total Tau (865.37 ± 304.93), and phosphorylated Tau (82.53 ± 15.77) deposition in the brain of the infection group. DISCUSSION: Nisin abrogation of brain microbiome dysbiosis induces beneficial effects on AD-like pathogenic changes and neuroinflammation, and thereby may serve as a potential therapeutic for periodontal-dysbiosis-related AD.

Interleukin-22 Inhibits Apoptosis of Gingival Epithelial Cells Through TGF-ß Signaling Pathway During Periodontitis.

Periodontitis is a chronic inflammatory disease characterized by the destruction of tooth-supporting tissues. The gingival epithelium is the first barrier of periodontal tissue against oral pathogens and harmful substances. The structure and function of epithelial lining are essential for maintaining the integrity of the epithelial barrier. Abnormal apoptosis can lead to the decrease of functional keratinocytes and break homeostasis in gingival epithelium. Interleukin-22 is a cytokine that plays an important role in epithelial homeostasis in intestinal epithelium, inducing proliferation and inhibiting apoptosis, but its role in gingival epithelium is poorly understood. In this study, we investigated the effect of interleukin-22 on apoptosis of gingival epithelial cells during periodontitis. Interleukin-22 topical injection and Il22 gene knockout were performed in experimental periodontitis mice. Human gingival epithelial cells were co-cultured with Porphyromonas gingivalis with interleukin-22 treatment. We found that interleukin-22 inhibited apoptosis of gingival epithelial cells during periodontitis in vivo and in vitro, decreasing Bax expression and increasing Bcl-xL expression. As for the underlying mechanisms, we found that interleukin-22 reduced the expression of TGF-ß receptor type II and inhibited the phosphorylation of Smad2 in gingival epithelial cells during periodontitis. Blockage of TGF-ß receptors attenuated apoptosis induced by Porphyromonas gingivalis and increased Bcl-xL expression stimulated by interleukin-22. These results confirmed the inhibitory effect of interleukin-22 on apoptosis of gingival epithelial cells and revealed the involvement of TGF-ß signaling pathway in gingival epithelial cell apoptosis during periodontitis.

Metabolism of periodontal pathobionts: Their regulatory roles in the dysbiotic microbiota.

The onset and development of periodontitis centers around microbiota dysbiosis and disrupted host responses. Dynamic metabolic activities of the subgingival microbiota modify the polymicrobial community, shape the microenvironment, and modulate the host response. A complicated metabolic network exists in interspecies interactions between periodontal pathobionts and commensals, which can lead to the development of dysbiotic plaque. Dysbiotic subgingival microbiota undergo metabolic interactions with the host and disrupt host-microbe equilibrium. In this review, we discuss the metabolic profiles of the subgingival microbiota, the metabolic crosstalk in polymicrobial communities, including pathobionts and commensals, and the metabolic interactions between microbes and the host.

JMJD3 Promotes Porphyromonas gingivalis Lipopolysaccharide-Induced Th17-Cell Differentiation by Modulating the STAT3-RORc Signaling Pathway.

The immune response mediated by Th17 cells is essential in the pathogenesis of periodontitis. Emerging evidence has demonstrated that lipopolysaccharide from Porphyromonas gingivalis (Pg-LPS) could promote Th17-cell differentiation directly, while the downstream signaling remains elusive. This study was aimed to explore the role of JMJD3 (a JmjC family histone demethylase) and signal transducers and activators of transcription 3 (STAT3) in Th17-cell differentiation triggered by Pg-LPS and clarify the interaction between them. We found that the expression of JMJD3 and STAT3 was significantly increased under Th17-polarizing conditions. Pg-LPS could promote Th17-cell differentiation from CD4+ T cells, with an increased expression of JMJD3 and STAT3 compared to the culture without Pg-LPS. The coimmunoprecipitation results showed that the interactions of JMJD3 and STAT3, STAT3 and retinoid-related orphan nuclear receptor γt (RORγt) were enhanced following Pg-LPS stimulation during Th17-cell differentiation. Further blocking assays were performed and the results showed that inhibition of STAT3 or JMJD3 both suppressed the Th17-cell differentiation, JMJD3 inhibitor could reduce the expression of STAT3 and p-STAT3, while JMJD3 expression was not affected when STAT3 was inhibited. Taken together, this study found that JMJD3 could promote Pg-LPS induced Th17-cell differentiation by modulating the STAT3-RORc signaling pathway.

SESN1, negatively regulated by miR-377-3p, suppresses invasive growth of head and neck squamous cell carcinoma by interaction with SMAD3.

Sestrin 1 (SESN1) is a stress-inducible protein that suppresses tumors in numerous cancers. However, the function of SESN1 in head and neck squamous cell carcinoma (HNSCC) is not clear and needs to be elucidated. Here, SESN1 expression was downregulated in HNSCC tissues and cell lines, and low SESN1 expression was positively correlated with poor prognosis in patients with HNSCC. Moreover, SESN1 overexpression inhibited the proliferation, migration, and invasion of HSC-6 and CAL-33 cells. In addition, the binding relationship between miR-377-3p and SESN1 was confirmed using luciferase reporter and RNA immunoprecipitation assays. Downregulation of SESN1 expression was consistent with high levels of miR-377-3p in HNSCC tissues. Linear regression analysis of clinical HNSCC tissues revealed a negative correlation between miR-377-3p and SESN1 expression. Moreover, co-immunoprecipitation mass spectrometry analysis revealed that SESN1 interacted with SMAD3, and SMAD3 reversed the increased proliferation, migration, and invasion of HSC-6 and CAL-33 cells caused by SESN1 knockdown. In conclusion, these findings provide evidence that SESN1 functions as a tumor suppressor and reveal the miR-377-3p-SESN1-SMAD3 regulatory axis that contributes to proliferation, migration, and invasion in HNSCC development, which may represent an interventional target for HNSCC therapy.

Porphyromonas gingivalis lipopolysaccharide promotes T-hel per17 cell differentiation by upregulating Delta-like ligand 4 expression on CD14+ monocytes.

BACKGROUD: To investigate the effect and mechanism of Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) on Th17 cell differentiation mediated by CD14+ monocytes. METHODS: P. gingivalis LPS-activated CD14+ monocytes were co-cultured with CD4+T cells in different cell ratios. An indirect co-culture system was also established using transwell chambers. Furthermore, anti- Delta-like ligand 4 (Dll-4) antibody was used to investigate the role of Dll-4 in Th17 cell response. The mRNA expression was analyzed using quantitative reverse transcription-polymerase chain reaction, and secreted cytokines in culture supernatant were detected using enzyme-linked immunosorbent assay. Flow cytometry was used to determine the frequencies of Th17 cells. IL-17 protein expression levels were determined using western blotting assay. RESULTS: P. gingivalis LPS increased the expressions of interleukin (IL)-1ß, IL-6, IL-23 and transforming growth factor (TGF)-ß in CD14+ monocytes. Th17 cell frequency upregulated, which is not solely cytokine-dependent but rather requires cell-cell contact with activated monocytes, particularly in the 1:10 cell ratio. Furthermore, P. gingivalis LPS increased t he expression of Dll-4 on CD14+ monocytes, whereas the anti- Dll-4 a ntibody decreased the response of Th17 cells. The results suggest that P. gingivalis LPS enhances Th17 cell response via Dll-4 upregulation on CD14+ monocytes.

Effect of interleukin-22 on osteogenic differentiation and the osteoclastogenic response of human periodontal ligament fibroblasts in vitro.

BACKGROUND: Interleukin-22 (IL-22) exerts extensive biological effects, playing both protective and pathological roles in autoimmune and infectious diseases. However, the specific role and mechanism of IL-22 in the pathogenesis of periodontitis have not been clarified. The aim of this study was to analyze the possible roles of IL-22 in the osteoclastogenesis and osteogenesis of periodontitis. METHODS: Human periodontal ligament fibroblasts (hPDLFs) were treated with IL-22 and/or lipopolysaccharide from Porphyromonas gingivalis (Pg-LPS), and the mRNA and protein expression of RANKL and OPG were measured by qRT-PCR and Western blotting, respectively. Western blotting was also used to examine the phosphorylated and total protein expression of MAPK signaling molecules. The role of the MAPK pathway in osteoclastogenesis marker expression was further confirmed by inhibition assays. For osteogenic assays, the mRNA expression of osteoblastic markers was quantified by qRT-PCR, the alkaline phosphatase (ALP) activity of hPDLFs was measured by an ALP assay, and the mineralized nodules formed by hPDLFs were determined by Alizarin Red S staining. RESULTS: IL-22 promoted the expression of RANKL in hPDLFs via the MAPK signaling pathway and further upregulated RANKL expression together with Pg-LPS via the p38 MAPK pathway. IL-22 could enhance the ALP activity and mineralized nodule formation of hPDLFs in the early period of osteogenic induction, while exhibiting no profound effect on the expression of osteoblastic markers. CONCLUSION: IL-22 plays regulatory roles in bone homeostasis, and it is likely to contribute to osteoclastogenesis as a proinflammatory cytokine in the pathogenesis of periodontitis.

Research on the roles of genes coding ATP-binding cassette transporters in Porphyromonas gingivalis pathogenicity.

Porphyromonas gingivalis, as a major pathogen of periodontitis, could rapidly adhere to and invade host gingival epithelial cells (GECs) for the induction of infection. One ATP-binding cassette (ABC) transporter gene was found to be upregulated during this infection process, however, the molecular mechanisms remain unclear. In this study, we systemically investigated the messenger RNA level changes of all ABC transporter family genes in P. gingivalis while being internalized within GECs by real-time polymerase chain reaction. We identified that two ABC transporter genes, PG_RS04465 (PG1010) and PG_RS07320 (PG1665), were significantly increased in P. gingivalis after coculturing with GECs. Mutant strains with knockout (KO) of these two genes were generated by homogenous recombination. PG_RS04465 and PG_RS07320 KO mutants showed no change in the growth of bacteria per se. Knockdown of PG_RS07320, but not PG_RS04465, caused decreased endotoxin level in the bacteria. In contrast, both mutant strains showed decreased Arg- and Lys-gingipains activities, with significantly reduced adhesion and invasion capabilities. Secreted interleukin-1ß (IL-1ß) and IL-6 levels in GECs cocultured with PG_RS04465 or PG_RS07320 KO mutants were also decreased, whereas, only the cells cocultured with PG_RS07320 KO mutants showed significant decrease. In addition, virulence study using mouse revealed that both KO mutant strains infection caused less mouse death than wild-type strains, showing reduced virulence of two KO strains. These results indicated that ABC transporter genes PG_RS04465 and PG_RS07320 are positive regulators of the virulence of P. gingivalis.

NFIC promotes the vitality and osteogenic differentiation of rat dental follicle cells.

Nuclear factor I-C (NFIC) plays critical roles in the regulation of tooth development by influencing the biological behaviors of stem cells in the dental germ. This study aimed to investigate the effect of NFIC on the vitality and osteogenic/cementogenic differentiation of rat dental follicle cells (DFCs). DFCs were isolated from dental follicles in the first molars of neonatal rats. DFCs expressed mesenchymal stromal cell markers CD29, CD44 and CD90 and had capabilities for self-renewal and multipotent differentiation. Overexpression of NFIC promoted the proliferation of DFCs without markedly influencing the apoptosis of DFCs. Moreover, NFIC increased alkaline phosphatase (ALP) activity in DFCs and upregulated the mRNA levels of osteogenic-related markers, namely, collagen type I (Col I), Runt-related transcription factor 2 (Runx2) and ALP, as well as ß-catenin. In contrast, silencing NFIC by siRNA increased the apoptosis of DFCs and downregulated the expression of osteogenic-related markers. In conclusion, these results suggested that upregulation of NFIC may promote the proliferation and osteogenic/cementogenic differentiation of DFCs.

Porphyromonas gingivalis lipopolysaccharide promotes T- helper 17 cell differentiation from human CD4+ naïve T cells via toll-like receptor-2 in vitro.

OBJECTIVES: The persistence of T-helper 17 (Th17) cells has been shown to support chronic inflammation and mediate tissue destruction in periodontitis. However, little is known regarding the underlying mechanisms that regulate Th17 cell differentiation in the periodontal inflammatory context. The objective of this study was to explore the possible effect and mechanism of lipopolysaccharide (LPS) from Porphyromonas gingivalis on Th17 cell differentiation. METHODS: Activated human CD4+CD45RA+ naïve T cells were stimulated with different doses of LPS from virulent and avirulent P. gingivalis strains combined with Th17 driven cytokines in vitro. Flow cytometry was used to analyze the differentiation ratio of Th17 cells. IL-17A protein expression and IL-17, retinoid-related orphan receptor C (RORC) and toll-like receptor 2 (TLR2) mRNA transcription were analysed by ELISA and real-time qPCR, respectively. The role of TLR2 in Th17 cell differentiation was further confirmed by TLR2 blocking assay. RESULTS: LPS from P. gingivalis (Pg-LPS) up-regulated Th17 cell differentiation ratios, expression of IL-17 and RORC mRNA, and IL-17 concentration in culture supernatant, with 0.1 µg/mL LPS from the virulent P. gingivalis strain being the most effectively. Furthermore, Pg-LPS also up-regulated expression of TLR2 on T cells during Th17 differentiation, and the differentiation was attenuated by treatment with TLR2 antibody. CONCLUSIONS: These results suggest that Pg-LPS promotes Th17 cell differentiation in vitro, and TLR2 signalling may be involved in this process. LPS from the virulent P. gingivalis strain up-regulated Th17 cell differentiation more effectively, which may be associated with the pathogenicity of different P. gingivalis strains.

Quantitative Evaluation of MMP-9 and TIMP-1 Promoter Methylation in Chronic Periodontitis.

In this study, we investigated the promoter DNA methylation (DNAm) status of the MMP-9 and TIMP-1 genes in patients with chronic periodontitis to evaluate disease progression. Using pyrosequencing technology, DNAm levels of MMP-9 and TIMP-1 CpG islands were measured in 88 chronic periodontitis patients and 15 healthy controls. We found a positive correlation between methylation levels of MMP-9 CpG islands and the severity of chronic periodontitis. Methylated CpG islands were also closely associated with the duration of chronic periodontitis. Moreover, female patients exhibited lower methylation levels of MMP-9 but higher methylation levels of TIMP-1 compared with male patients, and the methylation levels of TIMP-1 gradually decreased with age. The findings of gender disparity in the DNAm of MMP-9 and TIMP-1 genes provide novel insights into chronic periodontitis.

The Dry Sliding Wear Properties of Nano-Sized TiCp/Al-Cu Composites at Elevated Temperatures.

Nano-sized ceramic particle reinforced aluminum composites exhibit excellent room-temperature mechanical properties. However, there is limited research on the dry sliding wear behavior of those composites at elevated temperatures, which should be one of the major concerns on elevated temperature applications. Here the Al-Cu composites reinforced with nano-sized TiCp were fabricated. The dry sliding wear behaviors of the nano-sized TiCp/Al-Cu composites at various temperatures (140-220 °C) and loads (10-40 N) with different TiCp contents were studied, and the results showed that the nanocomposites exhibited superior wear resistance. For instance, the relative wear resistance of the 0.5 wt.% nano-sized TiCp/Al-Cu composite was 83.5% higher than that of the Al-Cu matrix alloy at 180 °C under 20 N, and was also 16.5% higher than that of the 5 wt.% micro-sized TiCp/Al-Cu composite, attributed to the pronounced Orowan strengthening effect of nanoparticles. The wear rates of the nanocomposites were always lower than those of the Al-Cu matrix alloy under the same test condition, which increased with the increase in temperature and load and with the decrease in TiCp content.

Detection of Th17/Treg cells and related factors in gingival tissues and peripheral blood of rats with experimental periodontitis.

OBJECTIVES: This study aimed to investigate the role and the possible mechanisms involved in the immunoregulation of experimental periodontitis by Th17/Treg. MATERIALS AND METHODS: Experimental periodontitis was established by silk thread ligation with Porphyromonas gingivalis daubing in the bilateral maxillary second molar of Male Sprague-Dawley (SD) rats. Alveolar bones were scanned by Micro-CT. Histological examination was stained with H&E. The proportions of Th17 and Treg cells in peripheral blood were detected by flow cytometry. RT-PCR was used to measure the expression of RORγt, Foxp3 mRNA in the gingival tissues. The concentrations of IL-17, IL-10, and TGF-ß in peripheral blood and gingival crevicular fluid were measured by ELISA. RESULTS: Experimental rats showed profound bone resorption and inflammatory cell infiltration. The percentages of Th17 significantly increased in the peripheral blood, which was consistent with gingival tissues study that Th17 cells related transcription factor RORγt mRNA and IL-17 increased in the course of periodontitis. The percentages of CD25+Foxp3+ Treg significantly increased in the peripheral blood, which was consistent with gingival tissues study that Treg cells related transcription factor Foxp3 mRNA and cytokines IL-10 and TGF-ß increased in the course of periodontitis. The ratio of Th17/Treg cells was significantly increased in the peripheral circulation, however, the Th17/Treg balance is in wave motion in inflamed gingival tissues in the different stages of periodontitis. CONCLUSION: Th17/Treg balance may be associated with the progression of periodontitis and pathological tissue destruction. Moreover, local inflammation would result in the up-regulation ratio of Th17/Treg in peripheral blood, which may influence some periodontally involved systemic diseases.

[Detection and functional analysis of CD-4+ CD-25+ regulatory T cells in the peripheral blood of patients with generalized aggressive periodontitis].

OBJECTIVE: To investigate the changes of proportion and suppression function of CD-4+ CD-25+ regulatory T cells in the peripheral blood of patients with aggressive periodontitis. METHODS: Flow cytometric analysis was used to detect the frequency of CD-4+ CD-25+ regulatory T cells in the peripheral blood of 16 patients with generalized aggressive periodontitis and 17 patients with chronic periodontitis, as well as 17 periodontal healthy controls. Furthermore, CD-4+ CD-25+ regulatory T cells and CD-4+ CD-25- T cells were separated from peripheral blood of each enrolling subject using magnetic cell sorting technology. The direct suppression effect of CD-4+ CD-25+ regulatory T cells on CD-4+ CD-25- T lymphocytes proliferation was performed by the mixed lymphocytes reaction and measured by 3H-thymidine radioactive assay. RESULTS: The patients with generalized aggressive periodontitis had a lower frequency of CD4+ CD-25+ regulatory T cells (9.71 +/- 4.01)% in the peripheral blood than periodontal healthy controls [(14.72 +/- 3.51)%] and chronic periodontitis patients [(17.01 +/- 5.16 )%], P < 0.05. A significant decrease was found in the suppression function of CD-4+ CD-25+ regulatory T cells from peripheral blood of patients with generalized aggressive periodontitis when co-cultured with CD-4+ CD-25- T lymphocytes in the proportion of 2 : 1, 1 : 1 and 1 : 2 as compared with chronic periodontitis patients and periodontal healthy controls (P < 0.05). CONCLUSIONS: Diminished numbers and decreased suppression function of CD-4+ CD-25+ regulatory T cells were found in patients with generalized aggressive periodontitis.