Association between serum miRNAs and gingival gene expression in an obese rat model.

INTRODUCTION: Recent studies have reported a relationship between periodontitis and obesity; however, the mechanisms of obesity's effects on periodontitis are not well understood. On the other hand, microRNAs (miRNAs) are known to play key roles in the post-transcriptional regulation gene expression by suppressing translation and protein synthesis. We examined the association between obesity-related miRNAs and gene expression in gingival tissue using miRNA-messenger RNA (mRNA) pairing analysis in an obese rat model. METHODS: Sixteen male Wistar rats aged 8 weeks old were divided into two groups: the control group was fed a normal powdered food for 8 weeks, and the obesity group was fed a high-fat diet for 8 weeks. Distance from the cement-enamel junction to the alveolar bone crest of the first molars was measured. miRNA microarray analysis was performed on samples of serum and gingival tissue; the resulting data were used to calculate fold changes in miRNA levels in the obesity group relative to the control group, and miRNA-mRNA pairing analysis was performed to identify mRNAs potentially targeted by miRNAs of interest. RESULTS: Alveolar bone loss in the obesity group exceeded that in the control group (p = .017). miRNA-mRNA pairing analysis identified an association between 4 miRNAs (miR-759, miR-9a-3p, miR-203b-3p, and miR-878) that were differentially expressed in the obesity and control groups and 7 genes (Ly86, Arid5b, Rgs18, Mlana, P2ry13, Kif1b, and Myt1) expressed in gingival tissue. CONCLUSION: This study revealed that several miRNAs play an important role in the mechanism of periodontal disease progression induced by the obesity.

Parafunctional masseter muscle activity during waking is related to periodontitis progression: A pilot prospective cohort study.

AIM: The purpose of this pilot prospective cohort study was to investigate the effects of parafunctional masseter muscle activity on periodontitis progression among patients receiving supporting periodontal therapy (SPT). MATERIALS AND METHODS: We collected data of patients treated at Okayama University Hospital from August 2014 to September 2018. The progression group was defined as patients with ≥2 teeth demonstrating a longitudinal loss of proximal attachment of ≥3 mm during the 3-year study period and/or at least one tooth extraction due to periodontitis progression. Surface electromyography of masseter muscles at baseline was continuously recorded while patients were awake and asleep. RESULTS: We analysed 48 patients (36 females) aged 66.8 ± 9.1 years (mean ± SD). The rate of parafunctional masseter muscle activity during waking hours and sleeping hours at baseline was 60.4% and 52.1%, respectively. Cox's proportional hazards regression model showed that the incidence of periodontitis progression was significantly associated with number of teeth present (p = 0.001) and parafunctional masseter muscle activity during waking hours (p = 0.041). CONCLUSION: Our results suggest that parafunctional masseter muscle activity during waking hours is a risk factor for periodontitis progression among patients receiving SPT.

Chain Structure in a Cross-Linked Polyurethane Magnetic Elastomer Under a Magnetic Field.

The morphology of magnetic particles with a size of 7.0 µm was observed for magnetic elastomers with a concentration of magnetic particles of 70 wt% using an X-ray microscope remolded into high resolution. Computed tomography images revealed that magnetic particles were distributed isotopically in the absence of a magnetic field, but they formed a chain structure in the polyurethane network under a magnetic field of 270 mT. It was also established, by image analysis, that magnetic elastomers had an anisotropic structure under the magnetic field.

Detection of Salivary miRNAs Reflecting Chronic Periodontitis: A Pilot Study.

The purpose of this cross-sectional pilot study was to find salivary microRNAs (miRNAs) reflecting periodontal condition in chronic periodontitis. One hundred and twenty chronic periodontitis patients (mean age, 68.4 years) participated in the study, from whom unstimulated whole saliva was collected. A multiphase study was conducted to explore salivary miRNAs as biomarkers of periodontitis. At first, a polymerase chain reaction (PCR) array was performed to compare salivary miRNAs profiles in no and mild (no/mild) and severe periodontitis patients. Next, the relative expression of salivary miRNAs on individual samples was assessed by real-time reverse transcription-PCR. The numbers (%) of patients were 26 (21.6%, no/mild), 58 (48.3%, moderate) and 36 (30.0%, severe), respectively. Among 84 miRNAs, only the relative expression of hsa-miR-381-3p in the severe periodontitis group was significantly higher than that of the no/mild periodontitis group (p < 0.05). Among the 120 patients, there was also a significant correlation between the relative expression of hsa-miR-381-3p and the mean probing pocket depth (PPD) (r = 0.181, p < 0.05). Salivary hsa-miR-381-3p was correlated with periodontitis condition in chronic periodontitis patients.

Expression of Salivary miR-203a-3p Was Related with Oral Health-Related Quality of Life in Healthy Volunteers.

Oral health-related quality of life (OHRQoL) is a multidimensional construct that involves subjective evaluation of an individual's oral health. Although it is difficult to evaluate OHRQoL biologically, recently, it has been reported that circulating microRNAs (miRNAs) in several body fluids could reflect various health conditions. The aim of this pilot study was to investigate whether salivary miRNAs expression differs according to OHRQoL in healthy volunteers. Forty-six volunteers (median age, 23.0 years) were recruited, and their OHRQoL was assessed using the Japanese version of the Oral Health Impact Profile (OHIP-J). Then, we compared salivary microRNA profiles of the high-OHRQoL group (≤25th percentile score of OHIP-J) and the low-OHRQoL group (≥75th percentile score of OHIP-J) using the polymerase chain reaction (PCR) array and the quantitative real-time PCR. There were no significant differences between the two groups in terms of oral health status. In the PCR array, miR-203a-3p and miR-30b-5p were significantly more expressed in the low-OHRQoL group (p < 0.05). Quantitative real-time PCR assay also showed that miR-203a-3p was more highly expressed in the low-OHRQoL group than in the high-OHRQoL group (p < 0.05). These observations suggest that expression of salivary miR-203a-3p was related with OHRQoL in healthy volunteers.

MicroRNAs as serum biomarkers for periodontitis.

AIM: Studies demonstrated that periodontitis modulates microRNA (miRNAs) expression rates in periodontal tissue. However, the relationship between periodontitis and miRNAs profile in circulation remains unclear. In this study, we investigated the effects of periodontitis on serum miRNAs profile in a rat model. MATERIAL AND METHODS: Male Wistar rats (n = 32, 8 weeks old) were divided into four groups of eight rats each. The control groups received no treatment for 2 or 4 weeks. In the other two groups, periodontitis was ligature induced for 2 or 4 weeks. Serum miRNAs expression profiles of each group were compared. RESULTS: Ligation around teeth induced periodontal inflammation at 2 weeks and periodontal tissue destruction at 4 weeks. Microarray results showed that 25 miRNAs were expressed with a <0.5 or >2 difference between the control and periodontitis groups at 4 weeks. Results of real-time PCR revealed that the periodontitis group up-regulated expression rates of serum miR-207 and miR-495 at 2 weeks, and miR-376b-3p at 4 weeks (p < 0.05). CONCLUSION: Serum miRNAs (miR-207, miR-495, and miR-376b-3p) could be valuable biomarkers for periodontitis.

MicroRNAs in Salivary Exosome as Potential Biomarkers of Aging.

The aim of this study was to examine whether salivary exosomal miRNAs could be identified as aging biomarkers. Fifteen young healthy volunteers (median age, 21.0 years) and 13 old individuals (median age, 66.0 years) were recruited. Unstimulated whole saliva was collected, salivary exosomes were isolated, and total RNA was extracted. In a microarray, 242 miRNAs were commonly detected in these two mixed samples. Based on the cut-off values of 2- or 0.5-fold changes (FC) and regulatory power for aging process, six candidate miRNAs (miR-24-3p, miR-371a-5p, miR-3175, miR-3162-5p, miR-671-5p, and miR-4667-5p) were selected. After comparing each total RNA obtained by the 15 young and 13 old individuals to validate the FC values using quantitative real-time PCR, miR-24-3p was identified as a novel candidate aging biomarker. This pilot study suggested that salivary exosomal miRNAs could be identified as candidate aging biomarkers. To confirm whether miR-24-3p in salivary exosomes are suitable biomarkers of aging, further validation research is required.

Effect of Antimicrobial Photodynamic Therapy on the Tongue Dorsum on Reducing Halitosis and the Duration of the Effect: A Randomized Clinical Trial.

Antimicrobial photodynamic therapy (PDT) is a treatment that is gaining popularity in modern clinical medicine. However, little is known about the effect of PDT alone on reducing oral halitosis and the duration of the effect. This trial examined the effect of PDT on the tongue dorsum on reducing oral halitosis and the duration of the effect. This study was approved by the Ethics Committee of Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, and Okayama University Hospital (CRB20-015), and it was registered in the Japan Registry of Clinical Trials (jRCTs061200060). Twenty-two participants were randomly assigned to two groups: an intervention group and control group. PDT was performed in the intervention group using red laser emission and methylene blue gel on the middle and posterior area of the tongue dorsum. The concentration of volatile sulfur compounds, bacterial count on the tongue dorsum, probing pocket depth, bleeding on probing, and simplified oral debris index score were determined before and 1 week after PDT. The Mann-Whitney U test was used to assess the significance of the differences in each parameter between the two groups. We found that the hydrogen sulfide concentration and bacterial count on the tongue dorsum were decreased in the intervention group, but there was no statistically significant difference between the two groups. These results indicated that performing only PDT on the tongue dorsum may not contribute to reducing halitosis.

Synthesis and evaluation of γ-lactam analogs of PGE2 as EP4 and EP2/EP4 agonists.

To identify topically effective EP4 agonists and EP2/EP4 dual agonists with excellent subtype selectivity, further optimization of the 16-phenyl ω-chain moiety of the γ-lactam 5-thia prostaglandin E analog and the 2-mercaptothiazole-4-carboxylic acid analog were undertaken. Rat in vivo evaluation of these newly identified compounds as their poly (lactide-co-glycolide) microsphere formulation, from which sustained release of the test compound is possible, led us to discover compounds that showed efficacy in a rat bone fracture healing model after its topical administration without serious influence on blood pressure and heart rate. A structure-activity relationship study is also presented.

Relationship between Psychological Stress Determined by Voice Analysis and Periodontal Status: A Cohort Study.

In modern society, evaluation and management of psychological stress may be important for the prevention of periodontal disease. The purpose of this study was to examine the relationship between psychological stress (vitality and mental activity) evaluated by Mind Monitoring System (MIMOSYS) and periodontal status. Forty students of Okayama University underwent the oral examination and self-reported questionnaire on the first day (baseline) and the 14th day (follow-up). Voice recording was performed every day with the MIMOSYS app during the whole study period. The participants completed the Patient Health Questionnaire (PHQ)-9 and Beck Depression Inventory (BDI) at baseline and at follow-up. Spearman's rank correlation coefficient was used to determine the significance of correlations among variables. The PHQ-9 and BDI scores were negatively correlated with vitality in the morning. Change in vitality in the morning was significantly correlated with changes in periodontal inflammation. Mental activity was significantly correlated with change in mean probing pocket depth. This result shows that measurement of psychological stress using a voice-based tool to assess mental health may contribute to the early detection of periodontal disease.

Trends in Self-Rated Oral Health and Its Associations with Oral Health Status and Oral Health Behaviors in Japanese University Students: A Cross-Sectional Study from 2011 to 2019.

Self-rated oral health (SROH) is a valid, comprehensive indicator of oral health status. The purpose of this cross-sectional study was to analyze how oral health behaviors and clinical oral status were associated with SROH and how they had changed over the course of nine years in Japanese university students. Data were obtained from 17,996 students who underwent oral examinations and completed self-questionnaires from 2011 to 2019. Oral status was assessed using the decayed and filled teeth scores, bleeding on probing (BOP), probing pocket depth, the Oral Hygiene Index-Simplified (OHI-S), oral health behaviors, and related factors. SROH improved from 2011 to 2019. The logistic regression model showed that university students who were female and had a high daily frequency of tooth brushing, no BOP, no decayed teeth, no filled teeth, and a low OHI-S score and were significantly more likely to report very good, good, or fair SROH. An interaction effect was observed between survey year and regular dental check-ups (year × regular dental check-ups). The improvement trend in SROH might be associated with changes in oral health behaviors and oral health status.

The Impact of Oral Health Behaviors, Health Belief Model, and Absolute Risk Aversion on the Willingness of Japanese University Students to Undergo Regular Dental Check-Ups: A Cross-Sectional Study.

Oral health behaviors, risk aversion, and the health belief model are associated with health behaviors. However, there have been few studies that investigated the association between these factors and the willingness to undergo regular dental check-ups. The purpose of this cross-sectional study was to investigate the associations between the willingness of Japanese university students to undergo regular dental check-ups and oral health behaviors, the health belief model, and absolute risk aversion. An analysis was conducted with the cooperation of questionnaire respondents (n = 748) who underwent dental check-ups at Okayama University. The students answered questionnaires on oral health behaviors, the health belief model, absolute risk aversion, and willingness to undergo regular dental check-ups. The logistic regression analysis showed significant positive associations (p < 0.05) between oral health behaviors (use of the inter-dental brush and the dental floss) and the health belief model with the willingness to undergo regular dental check-ups. However, there was no significant association with absolute risk aversion (p > 0.05). These results suggest that willingness to undergo regular dental check-ups was associated with oral health behaviors and the health belief model, but not with absolute risk aversion.

Detection of Salivary miRNAs That Predict Chronic Periodontitis Progression: A Cohort Study.

The aim of this two-year cohort study was to investigate salivary microRNAs (miRNAs) that predict periodontitis progression. A total of 120 patients who underwent supportive periodontal therapy were recruited. Unstimulated whole saliva was collected at baseline. Two years later, 44 patients were followed up (median age, 67.1 years) and divided into two groups: progression group (n = 22), with one or more sites with clinical attachment level (CAL) progression (>3 mm compared with baseline) or tooth extraction due to periodontitis progression; and the control group (n = 22), which did not exhibit CAL progression. In the microarray analysis of salivary miRNAs, hsa-miR-5571-5p, hsa-miR-17-3p, hsa-let-7f-5p, hsa-miR-4724-3p, hsa-miR-99a-5p, hsa-miR-200a-3p, hsa-miR-28-5p, hsa-miR-320d, and hsa-miR-31-5p showed fold change values <0.5 or ≥2.0 in the progression group compared with the control group (p < 0.05). On receiver operating characteristic curve analysis, areas under the curves of hsa-miR-5571-5p, hsa-let-7f-5p, hsa-miR-99a-5p, hsa-miR-28-5p, and hsa-miR-320d were >0.7, indicating fair discrimination power. The expressions of salivary hsa-miR-5571-5p, hsa-let-7f-5p, hsa-miR-99a-5p, hsa-miR-28-5p, and hsa-miR-320d were associated with periodontitis progression in patients with chronic periodontitis. These salivary miRNAs may be new biomarkers for progression of periodontitis, and monitoring them may contribute to new diagnostics and precision medicine for periodontitis.

Effects of Coffee Intake on Oxidative Stress During Aging-related Alterations in Periodontal Tissue.

BACKGROUND/AIM: The purpose of this study was to determine the anti-aging effects of coffee intake on oxidative stress in rat periodontal tissue and alveolar bone loss. MATERIALS AND METHODS: Male Fischer 344 rats (8 weeks old) were randomized to four groups; the baseline group immediately sacrificed, the control group fed with normal powdered food for 8 weeks, and the experimental groups fed with powdered food containing 0.62% or 1.36% coffee components for 8 weeks. RESULTS: Alveolar bone loss and gingival level of 8-hydroxydeoxyguanosine were significantly lower in the 1.36% coffee group than in the control group. Nuclear factor erythroid 2-related factor 2 translocation to the nucleus was significantly higher in the 1.36% coffee group than in the control group. CONCLUSION: Continuous intake of 1.36% coffee could prevent age-related oxidative stress in the periodontal tissue and alveolar bone loss, possibly by up-regulating the Nrf2 signaling pathway.

Detection of Serum miRNAs Affecting Liver Apoptosis in a Periodontitis Rat Model.

BACKGROUND/AIM: miRNA molecules have been attracting attention as genetic modifiers between organs. We examined the relationship between serum miRNA and targeted liver mRNA profiles in a periodontitis rat model, and the influence of periodontitis on the liver. MATERIALS AND METHODS: Male Wistar rats (n=16, 8 weeks old) were randomly divided into two groups (8 rats each): control and periodontitis (ligature placement for 4 weeks). Serum miRNA and liver mRNA profiles were compared. RESULTS: Periodontal destruction and hepatocyte apoptosis were induced in the periodontitis group. Microarray analysis indicated that 52 serum miRNAs and 33 liver mRNAs were expressed with a >1.5-fold change (FC) and a >2.0-FC (p<0.05), respectively, between the two groups. From the miRNA target genes, 12 genes equivalented to liver mRNAs with a >2.0-FC, among which, Hyou1, Chac1, and Bloc1s3 have apoptotic functions in our model. miRNAs upstream of these 3 mRNAs are miR-3591, miR-181a-2-3p and miR-6321. CONCLUSION: miR-3591, miR-181a-2-3p and miR-6321 induced hepatocyte apoptosis in our periodontitis rat model.

Effects of improvement in periodontal inflammation by toothbrushing on serum lipopolysaccharide concentration and liver injury in rats.

OBJECTIVE: Periodontitis increases the serum lipopolysaccharide level, contributing to liver injury. Toothbrushing improves periodontitis and may also affect serum lipopolysaccharide concentration and periodontitis-induced liver injury. The purpose of the present study was to examine whether the improvement in periodontal inflammation by toothbrushing clinically affects the serum lipopolysaccharide level and hepatic pathological changes in rat periodontitis. MATERIAL AND METHODS: Thirty male Wistar rats were divided into 5 groups, 2 groups receiving topical application of pyrogen-free water to the gingival sulcus for 4 or 8 weeks. The next 2 groups received topical application of lipopolysaccharide and proteases for 4 or 8 weeks. The last group received topical application of lipopolysaccharide and proteases for 8 weeks, and the palatal gingiva was brushed with a powered toothbrush once a day for 4 weeks prior to the end of the experimental period. RESULTS: Topical application of lipopolysaccharide and proteases induced not only periodontal inflammation but also an elevation in the serum lipopolysaccharide concentration, with increasing hepatic inflammation, steatosis and 8-hydroxydeoxyguanosine levels in a time-dependent manner. The rats that received gingival stimulation showed decreased polymorphonuclear leukocyte infiltration and collagen loss levels in the periodontal lesions. Furthermore, this group also showed a decrease in serum lipopolysaccharide concentration and hepatic inflammation, steatosis and 8-hydroxydeoxyguanosine levels, compared with the group receiving no treatment. CONCLUSIONS: Toothbrushing promoted healing of periodontal lesions, decreased serum lipopolysaccharide concentration and suppressed liver injury in a rat periodontitis model.

Relationship between acetaldehyde concentration in mouth air and characteristics of microbiota of tongue dorsum in Japanese healthy adults: a cross-sectional study.

OBJECTIVE: Acetaldehyde, associated with consumption of alcoholic beverages, is known to be a carcinogen and to be related to the tongue dorsum. The aim of this study was to investigate the relationship between acetaldehyde concentration in mouth air and bacterial characteristics on the tongue dorsum. METHODOLOGY: Thirty-nine healthy volunteers participated in the study. Acetaldehyde concentrations in mouth air were evaluated by a high-sensitivity semiconductor gas sensor. A 16S rRNA gene sequencing technique was used to compare microbiomes between two groups, focusing on the six samples with the highest acetaldehyde concentrations (HG) and the six samples with lowest acetaldehyde concentrations (LG). RESULTS: Acetaldehyde concentration increased in correlation with the increase in bacterial count (p=0.048). The number of species observed in the oral microbiome of the HG was higher than that in the oral microbiome of the LG (p=0.011). The relative abundances of Gemella sanguinis, Veillonella parvula and Neisseria flavescens in the oral microbiome of the HG were higher than those in the oral microbiome of the LG (p<0.05). CONCLUSION: Acetaldehyde concentration in mouth air was associated with bacterial count, diversity of microbiome, and relative abundance of G. sanguinis, V. parvula, and N. flavescens.

Serum microRNAs and chronic periodontitis: A case-control study.

OBJECTIVE: An association is present between periodontitis and rates of expression of certain microRNAs (miRNAs) in periodontal tissue. However, the association between periodontitis and miRNA levels in human serum is unknown. We performed a case-control study in patients with chronic periodontitis to investigate serum miRNA levels. DESIGN: We enrolled 30 healthy patients without periodontitis and 30 patients with chronic periodontitis. Participants underwent clinical examination, case selection, and a blood draw from the antecubital vein. Serum miRNA profiles were compared in samples from participants with and without chronic periodontitis using microarray and real-time PCR. RESULTS: Microarray demonstrated seven miRNAs that were expressed <1/1.5 or >1.5 in the control group compared to the periodontitis group (p < 0.05). Real-time PCR showed that hsa-miR-664a-3p, hsa-miR-501-5p, and hsa-miR-21-3p were higher in the periodontitis group than the control group (p < 0.05). CONCLUSION: Hsa-miR-664a-3p, hsa-miR-501-5p, and hsa-miR-21-3p are candidate serum biomarkers for chronic periodontitis.

Relationship between periodontal condition and plasma reactive oxygen metabolites in patients in the maintenance phase of periodontal treatment.

BACKGROUND: The relationship between systemic antioxidative status and periodontal condition has been investigated in epidemiologic studies. However, little literature is available with regard to the correlation between systemic reactive oxygen species and periodontal condition. The purpose of this cross-sectional study was to investigate the relationship between plasma reactive oxygen metabolites (ROM) and periodontal condition in patients in the maintenance phase of periodontal treatment. METHODS: Eighty-one subjects (mean age: 57.4 years) who had entered a periodontal maintenance program were examined for probing depth (PD) and clinical attachment level (CAL). Plasma levels of ROM and biologic antioxidant potential (BAP) were determined with a free radical electric evaluator. RESULTS: The plasma level of ROM was positively correlated to mean CAL (r = 0.281; P = 0.011) and percentage of teeth with CAL > or =4 mm (r = 0.236; P = 0.034), but not mean PD (r = 0.196; P = 0.080). Logistic regression analysis showed that subjects with ROM levels >400 Carratelli units (CARR U) had significantly higher mean CAL compared to subjects with ROM < or =400 CARR U after adjusting for age, gender, and the number of teeth present (P = 0.011). However, the plasma level of BAP was not significantly correlated with the periodontal parameters. CONCLUSIONS: A positive association was found between plasma oxidative status and CAL in patients in the maintenance phase of periodontal therapy. A systemic increase in oxidative stress may influence the rate of progression of periodontal disease.

New oral hygiene care regimen reduces postoperative oral bacteria count and number of days with elevated fever in ICU patients with esophageal cancer.

Using a controlled pre/post study design, we investigated the effects of professional mechanical cleaning of the oral cavity with benzethonium chloride, interdental brushes, and hydrogen peroxide on the number of oral bacteria and postoperative complications among esophageal cancer patients in an intensive care unit. Before surgery, 44 patients with esophageal cancer were recruited at Okayama Hospital from January through August 2015. The control group (n = 23) received routine oral hygiene care in the intensive care unit. The intervention group (n = 21) received intensive interdental cleaning with benzethonium chloride solution and tongue cleaning with hydrogen peroxide. The number of oral bacteria on the tongue surface and plaque index were significantly lower in the intervention group than in the control group on postoperative days 1 and 2 (P < 0.05). Additionally, the number of days with elevated fever during a 1-week period was significantly lower in the intervention group than in the control group (P = 0.037). As compared with routine oral hygiene, a new oral hygiene regimen comprising benzethonium chloride, interdental brushes, and hydrogen peroxide significantly reduced the number of oral bacteria and days with elevated fever in patients with esophageal cancer.