Hideaki Hayashida

The relationship between periodontal condition and serum levels of resistin and adiponectin in elderly Japanese

BACKGROUND AND OBJECTIVE Diabetes and periodontitis are associated with each other. Adipokines, specifically adiponectin and resistin, are secreted from adipocytes and are thought to cause insulin resistance in rodents. Additionally, adiponectin and resistin may play a role in inflammation and immune responses. The aim of this study was to clarify the relationship between serum levels of adipokines and periodontal conditions in elderly Japanese people with and without periodontitis. MATERIAL AND METHODS A total of 158 Japanese men and women (76 years old) with or without periodontitis were selected for the study. Serum adiponectin, resistin, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) concentrations were compared between subjects with and without periodontitis. RESULTS Serum resistin levels and total leukocyte counts in subjects with periodontitis were higher than in control subjects. No significant differences were observed in adiponectin, IL-6 and TNF-alpha levels between subjects with and without periodontitis. Logistic regression analysis showed that periodontitis with at least one tooth that displayed a probing pocket depth of > or =6 mm was significantly associated with higher serum resistin levels (odds ratio, 2.0; 95% confidence interval, 1.0-4.0). When excluding periodontitis subjects with < or =10% of bleeding on probing and excluding control subjects with >10% bleeding on probing, differences between groups and odds ratio increased. Serum adiponectin tended to decrease in patients with periodontitis, albeit not significantly. CONCLUSION Increased serum resistin levels were significantly associated with periodontal condition, especially when considering bleeding on probing, in elderly Japanese people. There was also a trend, though non-significant, toward decreased levels of adiponectin in subjects with periodontitis.

Relationship Between Periodontal Status and HbA1c in Nondiabetics

OBJECTIVES Many studies have reported an association between diabetes and periodontitis. We analyzed the periodontal status and glycosylated hemoglobin (HbA1c) level in nondiabetic subjects to investigate the relationship between periodontitis and glucose control in nondiabetics. METHODS Periodontal status, HbA1c, serum cholesterol, triglyceride, body mass index (BMI), and demographic variables were assessed in 141 Japanese adults. The difference in the HbA1c level was evaluated among subjects according to periodontal status. RESULTS After adjusting for age, gender, BMI, and smoking, alcohol, and exercise habits as covariates, the mean HbA1c was significantly elevated with periodontal deterioration (P = 0.023). CONCLUSIONS There was a significant relationship between periodontal status and HbA1c levels in nondiabetics.

Cloning and sequencing of the groESL homologue from Porphyromonas gingivalis

The homologue of groESL from Porphyromonas gingivalis was cloned and sequenced. Nucleotide sequencing suggested an operon containing two open reading frames (ORFs) homologous to groESL operon of Escherichia coli. The upstream ORF consisted of 267 bp corresponding to 89 amino acid residues. The downstream ORF consisted of 1635 bp corresponding to 545 amino acid residues.

Association of periodontitis with carotid artery intima–media thickness and arterial stiffness in community-dwelling people in Japan: The Nagasaki Islands study

OBJECTIVE Recent studies have suggested an association between periodontitis and atherosclerosis; however, the relationship between periodontal status and arterial alterations should be clarified. The purpose of this study was to examine associations between periodontal status and carotid intima-media thickness (cIMT) and arterial stiffness using the cardio-ankle vascular index (CAVI) in community dwellers. METHODS A community-based cross-sectional study of 1053 subjects ≥40 years with 10 teeth or more was conducted in Goto, Japan from 2008 to 2010. RESULTS In a multiple linear regression analysis adjusted for age, sex, number of present teeth, and other confounders, each 1-mm increase in mean periodontal pocket depth corresponded to a 0.02-mm increase in maximal cIMT (β = 0.018; P = 0.049) and also to a 0.1 increase in mean CAVI (β = 0.133; P = 0.040). In addition, each 1-mm increase in the mean periodontal attachment loss corresponded to a 0.01-mm increase in maximal cIMT (β = 0.013; P = 0.040). A multiple logistic regression analysis revealed that each 1-mm increase in mean periodontal pocket depth was associated with an increased risk of a maximal cIMT >1 mm (adjusted odds ratio [OR], 1.430; 95% confidence interval [CI], 1.067-1.918; P = 0.017) and mean CAVI of ≥8 (OR, 1.323; 95% CI, 1.003-1.743; P = 0.047). Furthermore, each 1-mm increase in mean periodontal attachment loss was associated with an increased risk of a maximal cIMT >1 mm (OR, 1.251; 95% CI, 1.032-1.516; P = 0.022). CONCLUSION A linear, dose-dependent relationship was found between periodontal pocket depth, cIMT, and arterial stiffness.

Molecular analysis of a new insertion sequence from Actinobacillus (Haemophilus) actinomycetemcomitans FDC Y4

We have found a new insertion sequence (IS), designated ISAa1, downstream of the S10 operon in Actinobacillus (Haemophilus) actinomycetemcomitans FDC Y4. ISAa1, the first IS element characterized in this organism, is 705 bp long and lacks terminal inverted repeats. This element displayed significant homology with IS200. Hybridization patterns of genomic DNA of seven A. actinomycetemcomitans strains with an internal ISAa1 probe varied depending on the serotypes, suggesting that ISAa1 might be a useful tool for epidemiological studies.

Porphyromonas gingivalis and Escherichia coli lipopolysaccharide causes resistin release from neutrophils

OBJECTIVES It was reported that periodontitis is associated with increased serum resistin levels. We examined whether there was a difference between the release of resistin from neutrophils incubated lipopolysaccharide (LPS) from Porphyromonas gingivalis and with LPS from Escherichia coli, and which cell-surface receptors and intracellular kinases were involved in this process. METHODS Several concentrations of P. gingivalis-LPS and E. coli-LPS were added to neutrophils, supernatant from cultured neutrophils was collected, and resistin levels were measured by ELISA. To examine signaling pathways, neutrophils were pretreated with monoclonal antibodies against CD14, CD18, TLR2, and TLR4, and specific inhibitors of PI3K and MAPKs. RESULTS Resistin release from neutrophils was induced both by P. gingivalis-LPS and E. coli-LPS, but resistin release by P. gingivalis-LPS was weaker than E. coli-LPS in low concentrations. Resistin release was decreased by pretreatment with monoclonal antibodies against CD14, CD18, and TLR4, but not by TLR2. Moreover, it was decreased by inhibitors of PI3K, JNK, and p38 MAPK, but not by ERK1/2. CONCLUSIONS Resistin release from neutrophils was induced by both P. gingivalis-LPS and E. coli-LPS. This was decreased by CD14, CD18, and TLR4 and was dependent on PI3K, JNK, and p38 MAPK, but not on ERK1/2 in intracellular pathways of neutrophils.

Neutrophil-derived resistin release induced by Aggregatibacter actinomycetemcomitans

Resistin is an adipokine that induces insulin resistance in mice. In humans, resistin is not produced in adipocytes, but in various leukocytes instead, and it acts as a proinflammatory molecule. The present investigation demonstrated high levels of resistin in culture supernatants of neutrophils that are stimulated by a highly leukotoxic strain of Aggregatibacter actinomycetemcomitans. In contrast, the level of resistin was remarkably low when neutrophils were exposed to two other strains that produce minimal levels of leukotoxin and a further isogenic mutant strain incapable of producing leukotoxin. Pretreatment of neutrophils with a monoclonal antibody to CD18, β chain of lymphocyte function-associated molecule 1 (LFA-1), or an Src family tyrosine kinase inhibitor before incubation with the highly leukotoxic strain inhibited the release of resistin. These results show that A. actinomycetemcomitans-expressed leukotoxin induces extracellular release of human neutrophil-derived resistin by interacting with LFA-1 on the surface of neutrophils and, consequently, activating Src family tyrosine kinases.

Comment on: Cani et al. (2007) Metabolic Endotoxemia Initiates Obesity and Insulin Resistance: Diabetes 56:1761–1772

The recent article by Cani et al. (1) interests us very much. We have reported that obesity and periodontitis were associated for the first time in 1998 (2). Further study revealed that hepatic impairment was more strongly associated with periodontitis than obesity indexes (3). Our results showed that periodontitis increased with elevated serum …

Relationship among salivary antioxidant activity, cytokines, and periodontitis: The Nagasaki Island study

AIM Antioxidant activities and cytokine levels in human body fluids are considered to be strongly associated with periodontitis. The aim of this study was to elucidate the relationship between salivary antioxidant activities against superoxide or hydroxyl radical, cytokines, and periodontal conditions through a community-based cross-sectional study conducted in Goto city, Japan. MATERIALS AND METHODS Saliva samples were analysed for superoxide or hydroxyl radical scavenging activities and cytokine levels from 160 participants. We demonstrated that saliva contained superoxide and hydroxyl radical scavenging activities by using electron spin resonance with a spin-trapping agent. The concentrations of eight cytokines were measured using multiplex bead assays. RESULTS There were significant differences in salivary superoxide or hydroxyl radical scavenging activity, and the levels of Interleukin-1β, Interleukin-6, and Interleukin-8 between periodontitis classifications. Multivariate stepwise logistic regression model showed that salivary superoxide and hydroxyl radical scavenging activities were significantly associated with the classification of periodontitis. In addition, salivary superoxide scavenging activity was found to have significant association with all periodontal parameters using multiple linear regression analysis. CONCLUSIONS These findings suggest that the evaluation of salivary antioxidant activities, as assessed by electron spin resonance, are associated with periodontitis and various clinical variables in community-dwelling participants (ClinicalTrials.gov number NCT01742728).

Quantitative discrimination of Aggregatibacter actinomycetemcomitans highly leukotoxic JP2 clone from non-JP2 clones in diagnosis of aggressive periodontitis

BackgroundAggregatibacter actinomycetemcomitans is the etiological agent of periodontitis, and there is a strong association between clone JP2 and aggressive periodontitis in adolescents of African descent. The JP2 clone has an approximately 530-bp deletion (∆530) in the promoter region of the lkt/ltx gene, which encodes leukotoxin, and this clone has high leukotoxic activity. Therefore, this clone is very important in aggressive periodontitis. To diagnose this disease, culture methods and conventional PCR techniques are used. However, quantitative detection based on qPCR for the JP2 clone has not been developed due to genetic difficulties. In this study, we developed a qPCR-based quantification method specific to the JP2 clone.MethodsBased on our analysis of the DNA sequence of the lkt/ltx gene and its flanking region, we designed a reverse primer specific for the ∆530 deletion border sequence and developed a JP2-specific PCR-based quantification method using this primer. We also analyzed the DNA sequence of the ∆530 locus and found it to be highly conserved (97–100%) among 17 non-JP2 strains. Using the ∆530 locus, we designed a qPCR primer–probe set specific to non-JP2 clones. Next, we determined the numbers of JP2 and non-JP2 clone cells in the periodontal pockets of patients with aggressive periodontitis.ResultsThe JP2-specific primers specifically amplified the genomic DNA of the A. actinomycetemcomitans JP2 clone and did not react with other bacterial DNA, whereas the non-JP2 specific primers reacted only with A. actinomycetemcomitans non-JP2 clones. Samples from the 88 periodontal sites in the 11 patients with aggressive periodontitis were analyzed. The bacterial cell numbers in 88 periodontal sites ranged from 0 to 4.8 × 108 (mean 1.28 × 107) for JP2 clones and from 0 to 1.6 × 106 for non-JP2 clones (mean 1.84 × 105). There were significant differences in the JP2 cell number between a clinical attachment level (CAL) ≤6 mm and a level ≥7 mm (p < 0.01). Our new qPCR-based JP2- and non-JP2-specific quantitative detection assay is applicable to the diagnosis of aggressive periodontitis with A. actinomycetemcomitans.ConclusionsWe successfully developed a quantitative and discriminative PCR-based method for the detection of A. actinomycetemcomitans JP2 and non-JP2 clones. This technique will contribute to future analyses of the quantitative relationship between this organism and aggressive periodontitis.