[Research Progress in Oral Diseases and Oral Microbiota of Organ Transplant Patients].

Organ transplantation is an effective treatment for end-stage organ diseases. However, organ transplant recipients are susceptible to a wide variety of oral diseases, including gingival enlargement, periodontitis, oral mucosal diseases, oral malignant tumors, and dental caries. Oral microbiota may have played an important role in the organ transplant patients' increased susceptibility to oral diseases and is associated with adverse events after organ transplantation, which is gradually gaining more attention among scholars. We, herein, reviewed the common oral diseases, including periodontal tissue diseases, oral mucosal diseases, oral malignant tumors, and dental caries in organ transplantation patients. Furthermore, we discussed the characteristic changes in the oral microbiota of organ transplantation patients and the influencing factors of these changes. In-depth study of oral microbiota of organ transplant patients provides a reference for the prevention and treatment of relevant diseases after organ transplantation and serves an important role in oral and systemic health management of organ transplant patients.

[Research Progress in the Association between Amino Acid Metabolism of Oral Microorganisms and Host Cells and Oral Diseases].

Amino acids, the substrate of protein synthesis, are an important source of energy and nutrition, second only to glucose. Previous studies have found that both microorganisms and their host cells can metabolize amino acids, and the metabolites are widely involved in the regulation of various biological processes, including inflammation and immune response. Exploring the changes in amino acid metabolism during the pathogenesis and progression of diseases has become a new hot topic of research. We summarized in this review the research progress in the pathogenesis and progression of common oral diseases, including dental caries, periodontal diseases, Sjögren's syndrome, and even oral tumors, related to metabolism pathways of amino acids, especially tryptophan and arginine, and their metabolites, attempting to provide a theoretical basis for enhancing understanding of the pathogenic mechanism of the oral diseases, as well as guidance for clinical treatment.

Molecular pathways underlying inhibitory effect of antimicrobial peptide Nal-P-113 on bacteria biofilms formation of Porphyromonas gingivalis W83 by DNA microarray.

BACKGROUND: Wound-related infection remains a major challenge for health professionals. One disadvantage in conventional antibiotics is their inability to penetrate biofilms, the main protective strategy for bacteria to evade irradiation. Previously, we have shown that synthetic antimicrobial peptides could inhibit bacterial biofilms formation. RESULTS: In this study, we first delineated how Nal-P-113, a novel antimicrobial peptide, exerted its inhibitory effects on Porphyromonas gingivalis W83 biofilms formation at a low concentration. Secondly, we performed gene expression profiling and validated that Nal-P-113 at a low dose significantly down-regulated genes related to mobile and extrachromosomal element functions, transport and binding proteins in Porphyromonas gingivalis W83. CONCLUSIONS: These findings suggest that Nal-P-113 at low dose is sufficient to inhibit the formation of biofilms although Porphyromonas gingivalis W83 may maintain its survival in the oral cavity. The newly discovered molecular pathways may add the knowledge of developing a new strategy to target bacterial infections in combination with current first-line treatment in periodontitis.

Preventive effects of the novel antimicrobial peptide Nal-P-113 in a rat Periodontitis model by limiting the growth of Porphyromonas gingivalis and modulating IL-1ß and TNF-α production.

BACKGROUND: P-113 (AKRHHGYKRKFH-NH2) is a 12-amino-acid histidine-rich peptide derived from histatin 5 that is highly degradable in high salt concentrations and biological fluids such as serum, plasma and saliva. Nal-P-113, a novel antimicrobial peptide whose histidine residues are replaced by the bulky amino acids ß-naphthylalanine, causes the antimicrobial peptide to retain its bactericidal activity even in physiological environments. This study evaluated the effect of the novel antimicrobial peptide Nal-P-113 in a rat periodontitis model and the mechanisms of action of Nal-P-113 for suppressing periodontitis. METHODS: Periodontitis was induced in mandibular first molars in rats receiving a ligature and infected with Porphyromonas gingivalis. Animals were randomly divided into six groups: a, P. gingivalis W83 alone; b, P. gingivalis W83 with 6.25 µg/mL of Nal-P-113; c, P. gingivalis W83 with 25 µg/mL of Nal-P-113; d, P. gingivalis W83 with 100 µg/mL of Nal-P-113; e, P. gingivalis W83 with 400 µg/mL of Nal-P-113; and f, control without P. gingivalis W83 or Nal-P-113. Morphometric analysis was used to evaluate alveolar bone loss. Microbiological assessment of the presence of Porphyromonas gingivalis and total bacteria was performed using absolute quantitative real-time PCR and scanning electron microscopy. Gingival tissue was collected for western blot and immunohistochemical assays of IL-1ß and TNF-α levels. RESULTS: Alveolar bone loss was inhibited by 100 µg/mL or 400 µg/mL of Nal-P-113 compared to the control group (P < 0.05). Lower amounts of P. gingivalis and total bacteria were found in groups d and e compared with group a (P < 0.05). A decrease in the levels of IL-1ß and TNF-α was detected in group d and group e compared to the control group (P < 0.05). The amount of P. gingivalis was positively correlated with IL-1ß and TNF-α expression in periodontal tissue (P < 0.05). CONCLUSIONS: Nal-P-113 exhibited protective effects on Porphyromonas gingivalis-induced periodontitis in rats by limiting the amount of bacteria and modulating IL-1ß and TNF-α production. The use of Nal-P-113 in vivo might serve as a beneficial preventive or therapeutic approach for periodontitis.

Gene expression changes in Porphyromonas gingivalis W83 after inoculation in rat oral cavity.

BACKGROUND: The development of chronic periodontitis was due to not only periodontal pathogens, but also the interaction between periodontal pathogens and host. The aim of this study is to investigate the alterations in gene expression in Porphyromonas gingivalis (P.gingivalis) W83 after inoculation in rat oral cavity. RESULTS: P.gingivalis W83 inoculation in rat oral cavity caused inflammatory responses in gingival tissues and destroyed host alveolar bone. Microarray analysis revealed that 42 genes were upregulated, and 22 genes were downregulated in the detected 1786 genes in the inoculated P.gingivalis W83. Real-time quantitative PCR detection confirmed the expression alterations in some selected genes. Products of these upregulated and downregulated genes are mainly related to transposon functions, cell transmembrane transportation, protein and nucleic acid metabolism, energy metabolism, cell division and bacterial pathogenicity. CONCLUSIONS: P.gingivalis W83 has a pathogenic effect on host oral cavity. Meanwhile, inflammatory oral environment alters P.gingivalis W83 gene expression profile. These changes in gene expression may limit the proliferation and weaken the pathogenicity of P.gingivalis W83, and favor themselves to adapt local environment for survival.

In vitro effect of Porphyromonas gingivalis combined with influenza A virus on respiratory epithelial cells.

OBJECTIVE: Respiratory epithelial cells are the first natural barrier against bacteria and viruses; hence, the interactions among epithelial cells, bacteria, and viruses are associated with disease occurrence and development. The effect of co-infection by P. gingivalis and influenza A virus (IAV) on respiratory epithelial cells remains unknown. The aim of this study was to analyze in vitro cell viability and apoptosis rates in respiratory epithelial A549 cells infected with P. gingivalis or IAV alone, or a combination of both pathogens. DESIGN: A549 cells were first divided into a control group, a P. gingivalis group, an IAV group, and a P. gingivalis + IAV group, to examine cell viability and apoptosis rates, the levels of microtubule associated protein 1 light chain 3 B (LC3-II), microtubule associated protein 1 light chain 3A (LC3-I), and sequestosome 1 (P62), and the formation of autophagosomes. The autophagy inhibitor, 3-methyladenine (3MA), was used to assess autophagy and apoptosis in A549 cells infected with P. gingivalis or IAV. RESULTS: An MTT assay revealed that cell viability was significantly lower in the IAV group than in the P. gingivalis + IAV group (P < 0.05). Flow cytometry indicated that the apoptosis rate was significantly higher in the IAV group than in the P. gingivalis + IAV group (P < 0.05). The fluorescence levels of GFP-LC3 increased significantly, the LC3-II/LC3-I ratio was significantly higher, and the P62 protein levels were statistically lower in the P. gingivalis + IAV group compared with the IAV group (all P < 0.05). Western blotting revealed that the LC3- II/LC3-I ratio was significantly lower, and caspase-3 levels were significantly higher in the 3MA + P. gingivalis + IAV group compared to the P. gingivalis + IAV group (all P < 0.05). CONCLUSION: In vitro studies showed that infection by P. gingivalis combined with IAV temporarily inhibited apoptosis in respiratory epithelial cells, and this may be related to the initiation of autophagy.

Resveratrol enhances the functionality and improves the regeneration of mesenchymal stem cell aggregates.

Mesenchymal stem cell (MSC)-based regeneration, specifically cell aggregate or cell sheet engineering, is a promising approach for tissue reconstruction. Considering the advantages of ease of harvest and lack of immune rejection, the application of autologous MSCs (i.e., patients' own MSCs) in regenerative medicine has developed considerable interest. However, the impaired cell viability and regenerative potential following MSCs impacted by disease remain a major challenge. Resveratrol (RSV) exhibits reliable and extensive rejuvenative activities that have received increasing clinical attention. Here, we uncovered that resveratrol enhances the functionality and improves the regeneration of mesenchymal stem cell aggregates. Periodontal ligament MSCs (PDLSCs) from normal control subjects (N-PDLSCs) and periodontitis patients (P-PDLSCs) were investigated. Compared to N-PDLSCs, P-PDLSCs were less capable of forming cell aggregates, and P-PDLSC aggregates showed impaired osteogenesis and regeneration. These functional declines could be mimicked in N-PDLSCs by tumor necrosis factor alpha (TNF-α) treatment. Notably, a TNF-α-induced functional decline in N-PDLSC aggregates was rescued by RSV application. More importantly, in both N-PDLSCs and P-PDLSCs, RSV promoted cell aggregate formation and improved their osteogenic potential. Furthermore, as proven ectopically in vivo, the tissue regenerative capability of P-PDLSC aggregates was also enhanced after RSV treatment during aggregate formation in vitro. Finally, in a rat in situ regeneration model, we successfully applied both N-PDLSC aggregates and P-PDLSC aggregates to repair periodontal defects upon long-term functional improvements by RSV preconditioning. Together, our data unravel a novel methodology for using pharmacology (i.e., RSV)-based cell aggregate engineering to improve the functionality and facilitate the regeneration of MSCs from both healthy and inflammatory microenvironments, shedding light on improving the application of autologous MSC-mediated regenerative medicine.

[Effectiveness of Nd:YAG laser with non-surgical periodontal therapy on improvement of periodontitis: meta analysis].

PURPOSE: To compare the effects of premolars restored with 2 different types of fiber post systems, so as to provide experience for restoration of residual crown of premolars. METHODS: Fifty-three residual crowns of premolar restored with fiber post systems were collected, and randomly divided into 2 groups: parallel fiber post group and double taper fiber post group. Repairing effect and operation difficulty were compared. The data was analyzed with SPSS 13.0 software package. RESULTS: There was no significant difference in success rate between the 2 groups, four complications occurred in parallel fiber post group and one in double taper fiber post group. CONCLUSIONS: The success rate between parallel fiber post groups and double taper fiber post group was not different, but the complication in double taper fiber post group is lower than parallel fiber post group.

[The improvement of periodontal teaching mode based on PDCA theory].

PURPOSE: To evaluate the effect of PDCA teaching mode on clinical ability in the process of periodontal clinical internship. METHODS: Forty-eight undergraduate interns coming from School of Stomatology, China Medical University were divided into 2 groups, one group received traditional teaching mode, the other group received a teaching mode based on PDCA cycle. At the end of internship, every student was assessed by theoretical examinations, case reports and clinical skill practice. χ2-test was used to determine the significant difference in clinical ability between the two groups. Statistical analysis was carried out using SPSS 13.0 software package. RESULTS: In clinical skill examination, 17 students in PDCA teaching mode group got "excellent" grade , 8 students got "good" grade, none student got "passed" grade; in traditional teaching mode group, 7 students got "excellent" grade, 16 students got "good" grade, 1 student got "passed" grade. The difference between the two groups was statistically significant (P<0.05). In the theoretical examinations and case reports, 16 students in PDCA teaching mode group got "excellent" grade, 8 students got "good" grade, none student got "passed" grade; in traditional teaching mode group, 12 students got "excellent" grade, 9 students got "good" grade, and 3 students got "passed" grade. The difference between the two groups wasn't statistically significant (P>0.05). CONCLUSIONS: PDCA teaching will train each student in a personalized mode, which is beneficial to finding defects existed in clinical practice and reinforcing the ability of communication and clinical practice.

[The impact of S.gordonii on P. gingivalis on the form of biofilm].

PURPOSE: To investigate the impact of S.gordonii on the ultrastructure of P. gingivalis biofilm and on the amount of P. gingivalis in biofilm. METHODS: P. gingivalis and/or S.gordonii grew on the culture slides to form single P. gingivalis biofilm and heterotypic biofilm of P.gingivalis-S.gordonii. Then the ultrastructure of the 2 kinds of film were examined by scanning electron microscope, and the amount of P. gingivalis in the biofilm was detected by qPCR. Statistical analysis was performed using pair t test with SPSS 13.0 statistical package. RESULTS: At 72 h, the amount of heterotypic biofilm was much more than that of the single P. gingivalis biofilm. Moreover, the structure of the heterotypic biofilm was more regular and with more pore space compared to the single P. gingivalis biofilm. Compared to single P. gingivalis biofilm, the amount of P. gingivalis in heterotypic biofilm was 5.4, 3.8 and 4.4 fold at 24, 48 and 72 h, respectively. CONCLUSIONS: The growth of P. gingivalis was promoted by S. gordonii in the form of heterotypic biofilm compared to single P. gingivalis biofilm.

Periodontal status of Pakistani orthodontic patients.

The objective of this study was to evaluate and compare the periodontal status of orthodontic patients and non-orthodontic patients, aged 15-28 years, of both genders. The cross-sectional study included 100 orthodontic and 100 non-orthodontic patients evaluated using a Community Periodontal Index for Treatment Need (CPITN) probe on the index teeth. A questionnaire was distributed to the participants to assess and evaluate the use of oral hygiene aids. The data were analyzed using SPSS version 17, and various comparisons were performed using the chi-square test. The study revealed that there was a statistically significant association in CPITN scores between the orthodontic and non-orthodontic patients (p < 0.01). The study showed that patients undergoing orthodontic treatment have increased plaque accumulation and probing depth resulting in periodontal tissue destruction. Proper oral hygiene practices and interdental aids should be employed to control plaque.

Efficacy of a novel antimicrobial peptide against periodontal pathogens in both planktonic and polymicrobial biofilm states.

Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis represent the early, middle and late colonizers of the bacterial accretion in dental plaque biofilms. These sessile communities constitute a protected mode of growth that promotes survival in a hostile environment. This study describes a novel and unrecognized role for a synthetic cationic antimicrobial peptide, Nal-P-113, which inhibits and kills periodontal bacteria in planktonic state, inhibits the formation of biofilms and eradicates polymicrobial biofilms. Nal-P-113 is also stable in saliva, serum and saline solution. At a concentration less than 320 µg/mL which is harmless to normal oral cells, Nal-P-113 can kill bacteria in planktonic state. At a concentration of antimicrobial peptide Nal-P-113 (1280 µg/mL) which only causes slight damages to normal oral cells is needed to kill bacteria in biofilm state. It is worth mentioning that this concentration of Nal-P-113 is harmless to rat oral mucosa compared to chlorhexidine. The mechanism of Nal-P-113 inhibiting and killing periodontal bacteria might rely on the abilities to permeabilize and/or to form pores within the cytoplasmic membranes, thus causes the death of bacteria. Here, we provided a novel and stable antimicrobial peptide with very low mammalian cytotoxicity, which can inhibit and kill periodontal bacteria in both planktonic and polymicrobial biofilm states. STATEMENT OF SIGNIFICANCE: Nal-P-113 is a potent antimicrobial peptide with strong antimicrobial ability, improved deficiency compared with other antibacterial peptides, and remains stable in phosphate buffered saline, saliva, brain-heart infusion medium and bovine calf serum. Nal-P-113 exhibits a broad spectrum of bacteriocidal activity with excellent eradicating capability on oral pathogens and the respective biofilms. In this study, we used propidium iodide staining, scanning electron microscopy and transmission electron microscopy to confirm that Nal-P-113 can perforate plasmalemma thereby resulting in the death of oral pathogens and disintegrate the respective biofilms. Nal-P-113 also showed effective anti-plaque biofilms and cytotoxicity in the rat periodontitis model. No adverse effects can be observed on the gingivomucosa tissue. In short, the antimicrobial peptide Nal-P-113 presented to be an effective yet have low mammalian cytotoxicity agent with potential application in the clinic. This study provides a proof of concept in applying antimicrobial peptides in the clinical perspective.

[Evaluation of alveolar bone defect in chronic periodontitis by cone-beam computed tomography].

OBJECTIVE: To evaluate the morphological characteristics of alveolar bone defects of the patients with chronic periodontitis using cone-beam CT (CBCT). METHODS: Sixty patients with chronic periodontitis were included in this study. CBCT was used to scan the alveolar bone and NNT software to measure the alveolar bone defects and bone loss types in different regions. RESULTS: Seventy-five percent (45/60) of the alveolar bone defect was the generalized type, 25% (15/60) was the localized type. In incisor and canine area, the defect of the mandibular alveolar bone was more severe than in the same sites of maxilla. There was less bone loss in the premolar area of mandible than in the same site of maxilla. In the mesial and buccal sites of mandibular molars and in the lingual site of maxillary molars, the most severe alveolar bone loss was found. CONCLUSIONS: The obvious alveolar bone defect areas in chronic periodontitis were the palatal side of maxillary molars and the lingual side of mandibular incisors. CBCT can clearly demonstrate the degree of alveolar bone defects in different regions of chronic periodontitis.

[Association between -590C/T polymorphisms of interleukin-4 gene and chronic periodontitis: a meta-analysis].

PURPOSE: To evaluate the relationship between -590C/T polymorphisms of interleukin-4 gene and chronic periodontitis using meta-analysis. METHODS: The selected studies were pooled from eight major electronic databases for case-control study. To gain a more precise estimation of the relationship, a stratified meta-analysis with two subgroups was performed according to the races. Heterogeneity, publication bias and sensitivity analysis were also explored. RESULTS: Totally 8 studies were recruited. Total sample sizes for chronic periodontitis and control groups were 628 and 717, respectively. Meta-analysis showed that both -590C/T polymorphisms and allele frequency were not significantly associated with chronic periodontitis. In subgroup analysis, a significant association of increased chronic periodontitis risk and T allele was found. The results also indicated a significant correlation between -590C/T polymorphisms of IL-4 and Caucasian who suffered from chronic periodontitis(C vs.T: OR=0.71,95% CI=0.56-0.89;CC vs.CT:OR=0.60,95% CI=0.38-0.94;recessive genetic model CC vs.CT+TT:OR=0.61,95% CI=0.42-0.88), further analysis of the results showed the CC genotype was about 39% less likely to have chronic periodontitis than the CT and TT genotype in Caucasian individuals.However, these significant associations was not found in Asian group. CONCLUSIONS: The meta-analysis suggests there may be an important effect of single nucleotide polymorphisms (SNPs) in the promoter region of IL-4 gene on the pathogenesis of chronic periodontitis in Caucasian. This warrants further investigation in larger studies and multi-race epidemiological to evaluate the results.

[17-ß estradiol promotes the expression of interleukin-6 in human periodontal ligament cells infected with Porphyromonas gingivalis].

OBJECTIVE: To investigate the effects of 17-ß estradiol (E(2)) and Porphyromonas gingivalis (Pg) W83 on the expression of interleukin (IL)-6 and IL-8 in human periodontal ligament cells (hPDLC). METHODS: Primary cultures of hPDLC were established and the cells of passage four were treated with 10(-10) mol/L E(2), 10(-7) mol/L E(2) or PgW83 individually or E(2) combined with PgW83. The expression levels of IL-6 and IL-8 protein at 12 h and 24 h were measured with enzyme-linked immunosorbent assay and the levels of mRNA at 24 h were detected with real-time reverse transcriptase polymerase chain reaction. RESULTS: The expression level of IL-6 reached (2482.88 ± 26.53) ng/L in hPDLC treated with Pg at multiplicity of infection (MOI) of 100 for 24 h, which was significantly higher than that in hPDLC treated with Pg at MOI of 10:1 [(734.09 ± 87.90) ng/L, P = 0.000], the controls [(425.8 ± 77.25) ng/L, P = 0.000] and that in hPDLC treated with Pg at MOI of 100 for 12 h [(1157.50 ± 234.65) ng/L, P = 0.000]. The expression level of IL-8 reached (4965.81 ± 1072.55) ng/L in hPDLC treated with Pg at MOI of 100 for 24 h, which was significantly higher than that in hPDLC treated with Pg at MOI of 10 [(803.51 ± 162.08) ng/L, P = 0.007], the controls [(400.75 ± 2.27) ng/L, P = 0.005] and that in hPDLC treated with Pg at MOI of 100 for 12 h [(1431.12 ± 82.78) ng/L, P = 0.001]. E(2) did not show remarkable effect on the expressions of IL-6 and IL-8. E(2) combined with Pg (MOI = 100:1) significantly promoted the expression levels of IL-6 at 24 h while did not influence those of IL-8. The relative mRNA level of IL-6 in hPDLC treated with 10(-10) mol/L E(2) or 10(-7) mol/L E(2) combined with Pg were 0.49 ± 0.15 (P = 0.021)and 0.53 ± 0.16 (P = 0.036) individually, which were significantly higher than that treated with Pg alone, 0.19 ± 0.06. The protein level of IL-6 in hPDLC treated with 10(-10) mol/L E(2) or 10(-7) mol/L E(2) combined with Pg were (5512.66 ± 1022.07) ng/L (P = 0.012) and (6988.78 ± 2279.13) ng/L (P = 0.000) individually, which were significantly higher than that treated with Pg alone, (3138.46 ± 183.72) ng/L. CONCLUSIONS: PgW83 significantly increased the expression levels of IL-6 and IL-8 in hPDLC in a dose-and time-dependent manner. Without the infection of periodontal pathogens, estrogen may exert no effect on the expression of IL-6 and IL-8 while it may promote the expression of IL-6 in hPDLC when combined with Pg, which may in turn promote the process of periodontal inflammation.

[Prevalence of Tannerella forsythensis in subgingival plaque of type 2 diabetic patients].

OBJECTIVE: To study the prevalence of Tannerella forsythensis (T. forsythensis) in the subgingival plaque of type 2 diabetes, analyze the relationship between Tforsythensis and related factors, discuss the role of T. forsythensis in the chronic periodontitis and type 2 diabetes. METHODS: 160 subgingival plaque samples were collected from type 2 diabetic patients and pathogens genomic DNA were extracted by phenol and chloroform from plaque. T. forsythensis was detected by polymerase chain reaction, and Pearson correlation and Logistic regression analysis were used to analyze the relationship between T. forsythensis and systemic factors and periodontal status. RESULTS: The prevalence of T. forsythensis in mild, moderate, severe periodontitis group was 47.82%, 48.71%, 67.39% respectively, and the prevalence was higher in the severe periodontitis group than in mild, moderate group (P < 0.05). There was no T. forsythensis in 6 diabetic patients with healthy periodontium. Logistic regression analysis illustrated that the prevalence of T. forsythensis was associated with simplified oral hygiene index (OHI-S) and diabetic duration (OR = 1.947, OR = 0.873). CONCLUSION: The prevalence of T. forsythensis in type 2 diabetes with chronic periodontitis was related with oral hygiene, periodontal status and diabetic duration.

[Effect of PG0839 gene of Porphyromonas gingivalis on inflammatory cytokine in human oral epidermoid carcinoma KB cell].

OBJECTIVE: To investigate the effect of PG0839 gene form Porphyromonas gingivalis (Pg) on inflammatory cytokine expression in human oral epidermoid carcinoma KB cell. METHODS: A mutant in the PG0839 gene of Pg was created by insertional inactivation. Group 1 was chanllenged with PgW83 strain, group 2 with PG0839-defective mutant, and the control group with Dulbecco's modified Eagle's medium only. KB cells were co-cultured with presence of bacteria for 24 h. At the time point of 0.5, 2, 6, 12 and 24 h, cells were stored in Trizol. The mRNA expression of interleukin-1ß (IL-1ß) and Toll like recepector-4 (TLR-4) was examined by reverse transcription polymerase chain reaction. RESULTS: At 2 h and 6 h, IL-1ß mRNA expression was lower in group 2 than in group 1 (2 h: 0.31 ± 0.11 versus 0.95 ± 0.48, P < 0.05; 6 h: 0.57 ± 0.20 versus 1.29 ± 0.55, P < 0.05). At 0.5 h and 6 h, TLR-4 mRNA expression was lower in group 2 than in group 1 (0.5 h: 0.20 ± 0.09 versus 0.58 ± 0.09, P < 0.05; 6 h: 0.34 ± 0.04 versus 0.71 ± 0.18, P < 0.05). CONCLUSIONS: PG0839 gene may play an important role in Pg-induced inflammatory effects of KB cell.

[Initial study of biological characterization and virulence of Porphyromonas gingivalis PG0839-defective mutant].

PURPOSE: To study the effect of PG0839 gene form Porphyromonas gingivalis (P. gingivalis) on biological characterization and virulence in a murine model of soft tissue destruction, and further to provide evidence for clarifying the gene function of PG0839. METHODS: P. gingivalis W83 and PG0839-defective mutant strains were plated on brain heart infusion (BHI). Colonial formation, micromorphology and growth curve of the two strains were observed. The two strains cells were mixed respectively with sheep erythrocytes, which were prepared to a final concentration of 1% in 1×PBS, to assess hemagglutination activity. The mice were challenged with subcutaneous injections of bacterial suspension,which were P. gingivalis W83 and PG0839-defective mutant strains at the doses of 2×10(10), 1×10(10), 5×10(9) CFU/mL respectively, on the dorsal surface. Difference in survival situation of mice in various groups was examined using Pearson Chi-square and log rank test with SPSS 13.0 software package. RESULTS: In contrast to the wild-type W83 strain, PG0839-defective mutant strain was nonpigmented and the hemagglutinin activities reduced. However, the growth rate of PG0839-defective mutant strain was not affected (U=25.50, P=0.19). Results of the mice subcutaneous infection model indicated that the virulence of the PG0839-defective mutant strain was significantly lower than P. gingivalis W83 strain (P<0.05). CONCLUSIONS: Absence of PG0839 gene altered several biological characteristics of P. gingivalis W83 strain, suggesting that PG0839 gene may regulate the expression of certain gene or gene product of P. gingivalis W83 strain. Moreover, PG0839 gene may contribute to the virulence of P. gingivalis W83.

[Effect of non-surgical periodontal therapy on glycemic control and the level of serum IL-6 in type 2 diabetic patients with chronic periodontitis].

OBJECTIVE: To evaluate the effect of non-surgical periodontal therapy on periodontal status, glycemic control and the level of serum interleukin (IL)-6 in type 2 diabetic patients with chronic periodontitis (DMCP). METHODS: Fifty-five DMCP and 55 systemically healthy patients with chronic periodontitis (CP) were recruited in this study. The diabetes were classified into two groups, the well-controlled group [glycated hemoglobin (HbA1c) < 7.00%] and the poorly controlled group (HbA1c ≥ 7.00%). All subjects received non-surgical periodontal therapy. Periodontal clinical parameters including periodontal probing depth(PD), attachment loss (AL), bleeding index (BI) and plaque index (PLI) were recorded at baseline, 6 weeks and 3 months after the treatment. Fasting plasma glucose (FPG), HbA1c and the concentration of serum IL-6 were measured. RESULTS: At 6 weeks and 3 months after treatment, PD, AL, BI, PLI and the concentration of serum IL-6 of both groups significantly reduced (P < 0.05). The level of IL-6 in diabetic patients reduced significantly from (3.47 ± 0.33) ng/L to (3.21 ± 0.66) ng/L and to(3.03 ± 0.54) ng/L. The HbA1c of diabetic patients reduced significantly 3 months after treatment [(6.80 ± 1.21%] compared with the baseline [(7.35 ± 1.73)%, P < 0.05]. HbA1c of the poorly controlled group reduced significantly (P < 0.05), while HbA1c of the well-controlled diabetes did not show any apparent reduction (P > 0.05). CONCLUSIONS: Non-surgical periodontal therapy can effectively reduce the concentration of serum IL-6, thereby improving glycemic control in type 2 diabetes patients with chronic periodontitis. However, there was no any significant reduction of HbA1c in the well-controlled diabetes.

[A study of frequency of TNF alpha gene with type 2 diabetes mellitus with chronic periodontitis].

PURPOSE: To detect the frequency of TNF alpha gene in patients of type 2 diabetes mellitus with chronic periodontitis, periodontitis without any systemic diseases and healthy controls. METHODS: The case series were consisted of 112 patients with moderate, severe type 2 diabetes mellitus with chronic periodontitis, 99 patients with moderate, severe periodontitis without any systemic disease, 50 age- and gender-matched subjects with healthy periodontal conditions were enrolled. Clinical parameters were measured and recorded including probing depth(PD), clinical attachment loss(CAL), bleeding index(BI), and tooth movement(TM). The polymorphism of TNF-α-308 genotype (TNF1/2) was examined after electrophoresis on agarose gel and ethidium bromide staining. The difference between the case and healthy groups was analysed by Chi-square test, the difference in clinical index among groups which had different allele was analyzed for ANOVA with SPSS13.0 software package. RESULTS: We divided DM and CP groups into moderate and severe groups. There were significant difference between severe DM group and severe, moderate CP group, moderate DM group and chronic periodontitis of severe,moderate group. The probing depth and clinical attachment loss of the patients who took TNF-α-308 allele II were significantly higher than the patients who took TNF-α-308 allele I in DM and CP group. CONCLUSIONS: TNF-α-308 allele II might increase the susceptivity of periodontitis in population. TNF-α-308 allele II may play an important role in synergistic reaction of periodontitis and type 2 diabetes.