The negative feedback regulation of microRNA-146a in human periodontal ligament cells after Porphyromonas gingivalis lipopolysaccharide stimulation.

OBJECTIVE: Toll-like receptors (TLRs) pathway has been demonstrated to play an important role in periodontitis. However, the regulatory mechanism of microRNAs (miRNAs) on TLRs pathway is still unclear. Hence, this study is to explore the function of miRNA-146a in inflammatory reaction induced by Porphyromonas gingivalis lipopolysaccharide (LPS) in human periodontal ligament cells (hPDLCs). METHODS: Cells were treated with 1 or 10 µg/ml P. gingivalis LPS. The expression of TLR2, TLR4 and miRNA-146a were measured by real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was applied to detect nuclear factor (NF)-κ B p65 nuclear activity, interleukin-1ß (IL-1ß), IL-6, IL-8 and tumor necrosis factor-α (TNF-α). To examine the underlying mechanisms, cells were exposed to anti-TLR2/4 mAb or miRNA-146a inhibitor/mimic and evaluated by real-time PCR and ELISA. RESULTS: 10 µg/ml P. gingivalis LPS increased the expressions of TLR2 (3.79 ± 0.31), TLR4 (2.21 ± 0.31), and miRNA-146a (4.91 ± 0.87), NF-κ B p65 nuclear activity (6.51 ± 0.77 fold) (p < 0.05). 1 µg/ml P. gingivalis LPS induced TLR2 (3.05 ± 0.23), miRNA-146a (3.66 ± 0.83) and NF-κ B p65 nuclear activity (4.06 ± 0.78 fold) (p < 0.05), except TLR4 (1.11 ± 0.30, p > 0.05). Also, cytokines production increased (p < 0.05). The up-regulation of miRNA-146a could be blocked by anti-TLR2/4 mAb (p < 0.05). After the blockage of miRNA-146a, TLR2, TLR4, NF-κ B p65 nuclear activity and proinflammatory cytokines increased. However, after application of miRNA-146a mimic, the levels of these indexes decreased obviously (p < 0.05). CONCLUSION: MiRNA-146a functions as a negative feedback regulator via down-regulating proinflammatory cytokine secretion and blocking TLRs signaling pathway in hPDLCs after P. gingivalis LPS stimulation.

[Effects of eicosapentaenoic acid on biological activity and inflammatory factor expression of human gingival fibroblasts].

PURPOSE: To explore the effects of eicosapentaenoic acid (EPA) on biological activity and inflammatory factor expression of human gingival fibroblasts (HGFs). METHODS: The effects of EPA on the activity, morphology and cell cycle of HGFs were observed by living and dead cell staining, immunofluorescence staining and flow cytometry, respectively. HGFs were stimulated by lipopolysaccharides (LPS) of Porphyromonas gingivalis (P. gingivalis) or heat inactivated P. gingivalis, after which the effects of EPA on mRNA and protein expression of IL-6, IL-8 and IL-1ß were observed by real-time PCR and ELISA, respectively. The gene and protein expression of heme oxygenase-1(HO-1) was also detected by real-time PCR and Western blotting, respectively. The data were analyzed with SPSS 22.0 software package. RESULTS: 200 µmol/L EPA inhibited cell activity of HGFs; 100 µmol/L EPA did not affect cell activity and morphology of HGFs, and had no significant effect on cell cycle (P>0.05). EPA significantly downregulated gene expression of IL-6 and IL-1ß, and protein expression of IL-6 stimulated by P. gingivalis LPS and heat-killed P.gingivalis(P<0.05), in a dose-dependent manner. EPA increased gene expression of HO-1 in a dose dependent manner(P<0.05), and upregulated HO-1 protein expression. CONCLUSIONS: EPA significantly inhibits the expression of inflammatory factors without affecting the biological activity of HGFs, which may be related to the induction of HO-1, suggesting the potential role of EPA in the prevention and treatment of periodontitis.

Statistical Analysis of Current Oral Health Care and Dental Education Resources in China.

OBJECTIVE: To collect information and statistical data regarding the current oral health care and dental education resources in China. METHODS: Electronic databases were searched and a literature review conducted. The homepages of relevant universities and colleges were visited to collect dental education information. In addition, private conversations with related experts were conducted. RESULTS: Compared with the 3rd National Oral Health Survey (2005), the ratio of gingival bleeding in individuals aged 33 to 44 years has increased in the last 10 years. The average percentage of residents visiting departments of dentistry in public hospitals is less than 10%. The total number of dentists and assistant dentists increased to 167,227 in 2016, with a ratio of 1.21 per 10,000 people. There is a great imbalance in the distribution of dental practitioners among the provinces. There are 101 dental schools or departments of stomatology that provide 5-year dental training courses and offer bachelor's degrees in dentistry, with another 93 dental institutions offering shorter 3-year training courses for assistant dentists. CONCLUSION: The results of the present study show that there has been significant change during recent years in China. However, the ratio of dental practitioners to the population as well as the number of dental visits carried out is still much lower than in developed countries and does not satisfy the demand for dental care in China. The quality and quantity of dental education, including continuing dental education, calls for improvement in the future.

Astroglial glutamate-glutamine shuttle is involved in central sensitization of nociceptive neurons in rat medullary dorsal horn.

Growing evidence suggests that astroglia are involved in pain states, but no studies have tested their possible involvement in modulating the activity of nociceptive neurons per se. This study has demonstrated that the central sensitization induced in functionally identified nociceptive neurons in trigeminal subnucleus caudalis (the medullary dorsal horn) by application of an inflammatory irritant to the rat's tooth pulp can be significantly attenuated by continuous intrathecal superfusion of methionine sulfoximine (MSO; 0.1 mM), an inhibitor of the astroglial enzyme glutamine synthetase that is involved in the glutamate-glutamine shuttle. Simultaneous superfusion of MSO and glutamine (0.25 mM) restored the irritant-induced central sensitization. In control experiments, superfusion of either MSO or glutamine alone, or vehicle, did not produce any significant changes in neuronal properties. These findings suggest that the astroglial glutamate-glutamine shuttle is essential for the initiation of inflammation-induced central sensitization but that inhibition of astroglial function may not affect normal nociceptive processing.

[Effect of exogenous ATP on NLRP3 inflammasome activation in gingival fibroblasts cells].

PURPOSE: To investigate exogenous ATP-dependent activation of NLRP3 inflammasome and interleukin-1ß ( IL-1ß) secretion in P.gingivalis infected and heat-killed P.gingivalis induced gingival fibroblasts cells ( hGFs) in vitro. METHODS: Gingival tissues were obtained from healthy patients and hGFs were cultured in vitro with tissue block method to harvest primary cells. HGFs was simulated by being treated with 100 MOI live P.gingivalis or 100 MOI heat-killed P.gingivalis (HP.gingivalis) after 5 mmol/L ATP pre-treatment. Real-time PCR was carried out to assess mRNA expression of NLRP3, ASC, caspase-1 and IL-1ß. The protein level of NLRP3 , caspase-1 and IL-1ß was evaluated by Western blot. IL-1ß secretion was measured using ELISA. Statistical analysis was performed using Graphpad prism 6 statistical package and the measurement data were analyzed by t test or one-way ANOVA. RESULTS: Compared with the control group, P.gingivalis downregulated NLRP3 mRNA and ASC mRNA while upregulated IL-1ß mRNA. Moreover, the protein expression of NLRP3 and IL-1ß was decreased. The gene and protein expression of NLRP3, ASC and IL-1ß was induced by HP.gingivalis, while caspase-1mRNA and IL-1ßsecretion was free from P.gingivalis or HP.gingivalis stimulus. All those genes as well as intracellular protein expression and IL-1ßsecretion were significantly potentiated with ATP/P.gingivalis or ATP/HP.gingivalis stimuli in hGFs. CONCLUSIONS: Exogenous ATP may be a potential stimulus signal in favour of NLRP3 inflammasome activation of hGFs and mediated inflammatory factor IL-1ß secretion.

Esthetic management of mucogingival defects after excision of epulis using laterally positioned flaps.

Epulis is a benign hyperplasia of the oral soft tissues. Surgical excision always extends to the periosteum and includes scaling of adjacent teeth to remove any possible irritants. The esthetics of the soft tissues may be compromised, however. This article studies three cases in which an immediate laterally positioned flap (LRF) was used to repair mucogingival defects after epulis biopsies. After 24 months, the color and shape of the surgical areas were healthy and stable, nearly complete root coverage was evident, and no lesions reoccurred. For repairing gingival defects after biopsy, LRF appears to be minimally traumatic while promoting esthetic outcomes.

miRNA-146 negatively regulates the production of pro-inflammatory cytokines via NF-κB signalling in human gingival fibroblasts.

OBJECTIVE: In human gingival fibroblasts (HGFs), TLR4 recognises Pathogen-associated molecular patterns (PAMPs), such as LPS, and subsequently activates downstream signals that lead to the production of pro-inflammatory cytokines. The aim of this study was to explore the mechanisms of LPS-induced miRNA-146 regulation of TLR4 signals in HGFs. MATERIALS AND METHODS: HGFs were treated with Porphyromonas gingivalis (P.g) LPS, the cells were harvested, and kinase phosphorylation levels were detected by western blot. Selective pharmacological inhibitors and agonists were used to block or activate the relevant kinases, miRNA-146a/b expression levels were detected by real-time PCR, and IL-1, IL-6, and TNF-α production were measured by enzyme-linked immunosorbent assays (ELISA). A luciferase reporter plasmid containing miRNA-146a/b promoter was tested in terms of p50/p65 regulation. RESULTS: After P.g LPS treatment, NF-κB and Erk1/2 were strongly activated in HGFs. miRNA-146a/b, IL-1, IL-6 and TNF-α levels were down-regulated when NF-κB inhibitor was used. p50/p65 strongly activated miRNA-146a/b promoter as measured with the luciferase assay. CONCLUSION: In TLR4 signalling in HGFs, both miRNA-146a and miRNA-146b are downstream targets of NF-κB, but not of AP-1 signalling. miRNA-146a/b expression was specifically dependent on NF-κB but not Erk1/2 or JNK signalling.

[A clinical study of osteotome sinus floor elevation and simultaneous implant placement in the periodontally compromised patients].

PURPOSE: To study the clinical effect of osteotome sinus floor elevation (OSFE) combined with simultaneous implant placement in the treatment of edentulous posterior maxilla subject to insufficient bone height in the periodontally compromised patients. METHODS: Forty-seven Straumanns implants were placed in the posterior maxilla in 35 patients with the procedure of OSFE. The final prostheses were restored after 3 to 6 months. The follow-up period was 6 to 30 months. Radiographs were taken and PD, PLI, BOP were measured and analyzed. RESULTS: The overall survival rate was 95.74% during the study period. Forty-five out of the 47 implants were clinically stable and loaded without pain or any subjective sensation. The perforation ratio of the membrane was 4.26%. The average of PD around the implants was (3.22±1.07) mm. The average of the marginal bone loss was (1.38±0.59) mm. CONCLUSIONS: OSFE without bone graft proves to be an effective and predictable treatment for atrophic edentulous posterior maxillary region in patients with periodontitis, but the long-term effect needs further observation.

MicroRNA-146 inhibits pro-inflammatory cytokine secretion through IL-1 receptor-associated kinase 1 in human gingival fibroblasts.

BACKGROUND: Although various microRNAs (miRNAs) regulate immune and inflammatory responses, the function of miRNAs in periodontitis has not been clearly illuminated. In this study, we measured miRNA-146 (miRNA-146a and miRNA-146b-5p) expression and explored its regulatory function in the inflammatory response in human gingival fibroblasts (HGFs). METHODS: miRNA-146a and miRNA-146b-5p expression was measured by performing real-time polymerase chain reaction in HGFs after Porphyromonas gingivalis (p.g) lipopolysaccharide (LPS) stimulation. After the HGFs were transfected with miRNA-146a and miRNA-146b-5p inhibitor, the expression levels of interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). Meanwhile, IL-1 receptor-associated kinase 1 (IRAK1) and TNF receptor-associated factor 6 (TRAF6) were detected by western blot and quantitative PCR. A luciferase assay was used to detect whether miRNA-146 could directly bind to the 3'-UTR of IRAK1. RESULTS: The expression levels of miRNA-146a and miRNA-146b-5p significantly increased in the P.g LPS-stimulated HGFs compared to the non-stimulated HGFs. The inhibition of miRNA-146a and miRNA-146b-5p resulted in increased IL-1ß, IL-6 and TNF-α secretion. The mRNA and protein levels of IRAK1, but not TRAF6, also increased. We further found that miRNA-146a and miRNA-146b-5p directly bound to the IRAK1 3'-UTR. CONCLUSION: Our data suggest that miRNA-146 inhibits pro-inflammatory cytokine secretion through IRAK1 in HGFs, which indicates that miRNA-146 functions as a negative regulator of periodontal inflammation.

Comparison of microRNA profiles of human periodontal diseased and healthy gingival tissues.

MicroRNAs (miRNAs) have been demonstrated to play an important role in regulation of the immunoinflammatory response; however, the function of miRNAs in periodontal inflammation has not been investigated. The objective of this study was to explore the properties of miRNAs in periodontal inflammation by comparing miRNA profiles of inflamed and healthy gingival tissues. Gingival tissues were obtained from 10 periodontitis patients and 10 healthy subjects. After RNA extraction, miRNA profiles were analyzed by microarray, and expression levels of selected miRNAs were confirmed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Analyses using two computational methods, Targetscan and MicroRNA.org, were combined to identify common targets of these miRNAs. Finally, the individual miRNA expression levels of three toll-like receptor (TLR)-related miRNAs from inflamed and healthy gingival tissues were evaluated by RT-PCR. Ninety-one miRNAs were found to be upregulated and thirty-four downregulated over two-fold in inflamed gingival tissue compared with those in healthy gingival tissue. Twelve selected inflammatory-related miRNAs, hsa-miR-126*, hsa-miR-20a, hsa-miR-142-3p, hsa-miR-19a, hsa-let-7f, hsa-miR-203, hsa-miR-17, hsa-miR-223, hsa-miR-146b, hsa-miR-146a, hsa-miR-155, and hsa-miR-205 showed comparable expression levels by microarray and real-time quantitative RT-PCR analyses. In addition, the putative inflammation targets of these miRNAs were predicted, and three that were tested (hsa-miRNA-146a, hsa-miRNA-146b, and hsa-miRNA-155), showed significant differences between inflamed and healthy gingiva. This remarkable difference in miRNA profiles between periodontal diseased and healthy gingiva implicates a probable close relationship between miRNAs and periodontal inflammation. The data also suggest that the regulation of TLRs in periodontal inflammation may involve miRNA pathways.

Cytocompatibility of regenerated silk fibroin film: a medical biomaterial applicable to wound healing.

OBJECTIVE: To explore the feasibility of using regenerated silk fibroin membrane to construct artificial skin substitutes for wound healing, it is necessary to evaluate its cytocompatibility. METHODS: The effects of regenerated silk fibroin film on cytotoxicity, adhesion, cell cycle, and apoptosis of L929 cells, growth and vascular endothelial growth factor (VEGF) expression of ECV304 cells, and VEGF, angiopoietin-1 (Ang-1), platelet-derived growth factor (PDGF) and fibroblast growth factor 2 (FGF2) expression of WI-38 cells were assessed by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, viable cell counting, flow cytometry (FCM), and enzyme-linked immunosorbant assay (ELISA). RESULTS: We showed that the regenerated silk fibroin film was not cytotoxic to L929 cells and had no adverse influence on their adhesion, cell cycle or apoptosis; it had no adverse influence on the growth and VEGF secretion of ECV304 cells and no effect on the secretion of VEGF, Ang-1, PDGF and FGF2 by WI-38 cells. CONCLUSION: The regenerated silk fibroin film should be an excellent biomaterial with good cytocompatibility, providing a framework for reparation after trauma in clinical applications.

[The effect of periodontal initial therapy on chronic periodontitis and subgingival periodontal pathogen].

PURPOSE: To evaluate the effect of periodontal initial therapy on clinical parameters and subgingival periodontal pathogen in patients with chronic periodontitis. METHODS: One hundred and twenty patients with chronic periodontitis were included. Probing depth (PD), attachment loss (AL), plaque index (PLI) and gingival index (GI) were evaluated at baseline and after-initial therapy. P.g and A.a in subgingival plaque were investigated by real-time PCR. Data was statistically analyzed by SAS6.12 software for Student's t test. RESULTS: The PD, AL, PLI and GI were significantly decreased after periodontal initial therapy (P<0.01), and meanwhile the ratio of P.g versus total bacteria was significantly decreased after-initial therapy (P<0.05). However, the change of ratio of A.a versus total bacteria was not significant (P>0.05). CONCLUSION: Periodontal initial therapy could effectively control the inflammation of chronic periodontitis, and decrease the ratio of P.g in subgingival plaque.

[An experimental study on biocompatibility of Bio-oss collagen with cultured bone marrow stromal cells].

PURPOSE: To study the biocompatibility of Bio-oss collagen with cultured bone marrow stromal cells. METHODS: The bone marrow stromal cells (BMSCs) of rhesus monkey were cultured with Bio-oss collagen in vitro. Cell attachment was observed with laser confocal microscope. Cell proliferation rates were assessed with MTT assay. ALP activity was also detected. The data was statistically analyzed with SAS6.12 software package for Student's t test. RESULTS: The rhesus BMSCs could attach to the surface of Bio-oss collagen. In cell proliferation rates, there was no significant difference between the control group and experimental group at 2-day and 5-day(P>0.05). However, at 8-day, the difference was significant (P<0.05). For ALP activity, there was no significant difference among different time point (P>0.05). CONCLUSIONS: The Bio-oss collagen has good biocompatibility with rhesus BMSCs, and could be used to repair periodontal bone defects as a biomaterial in tissue engineering.

[Analysis of FcgammaRIIIb genotype of periodontal disease in the Han nationality in China].

PURPOSE: The purpose of the present study was to compare FcgammaRIIIb genotype of aggressive periodontitis (AgP) with chronic periodontitis (CP) and control group (Cont) in the Han nationality in China. METHODS: The classification, which was applied in this study, was presented and discussed at the 1999 International Workshop for the Classification of the Periodontal Disease organized by the American Academy of Periodontology (AAP). 23 patients with aggressive periodontitis, including 20 with chronic periodontitis according to the established clinical criteria, and 22 matched healthy controls was included in this study. Peripheral blood samples were taken from all patients and controls, then DNA was isolated from blood using DNA purification kit. And FcgammaRIIIb genotyping was determined by PCR and DNA sequencing. The different results of genotype in all three groups were analysed by chi(2) test. RESULT: FcgammaRIIIb-NA1, -NA2 (old definition) frequencies didn't equal 1.00 in all 3 groups, and also without -SH, -NA(NULL) genotype. At the same time, many new allele of NA1 and NA2 were found in all groups. However, there were no rules of new alleles in each group and between the groups, no statistical significance as well. The -NA1 of FcgammaRIIIb (new definition) frequency was 0.77, and that of -NA2 (new definition) was 0.23 in this study. CONCLUSION: Including FcgammaRIIIb-NA1 and -NA2, five alternate allele of -NA1 (-NA1*01b, -NA1*02a, -NA1*02b, -NA1*03a and-NA1*03b) and three alternate allele of -NA2(-NA2*02, -NA2*03 and -NA2*04) were described. The results suggest that FcgammaRIIIb may not be a risk indicator for the susceptibility of periodontitis in the Han nationality of China.