Obesity and periodontitis

Environmental tobacco smoke exposure and periodontitis prevalence among nonsmokers in the hispanic community Health Study/Study of Latinos

OBJECTIVE

To describe self-reported exposure to environmental tobacco smoke (ETS) and its association with periodontitis prevalence in a diverse group of Hispanics/Latinos.

METHODS

Data came from 8675 lifetime nonsmokers in the 2008-2011 Hispanic Community Health Study/Study of Latinos. Exposure to ETS was self-reported, while periodontitis was defined using the Centers for Disease Control and Prevention-American Academy of Periodontology criteria and the proportion of sites affected by clinical attachment level of ≥3 mm or pocket depth of ≥4 mm. Survey logistic regression estimated prevalence odds ratios (POR) and 95% confidence intervals (CI). In addition, we assessed whether greater hours of exposure to ETS in the past year was associated with greater periodontitis prevalence, and lastly, we conducted a simple sensitivity analysis of ETS misclassification.

RESULTS

Age-standardized prevalence estimates (95% CI) for ETS exposure and periodontitis were 57.6% (55.9, 59.4) and 39.8% (38.1, 41.4), respectively. After adjusting for confounders and periodontitis risk factors, we estimated an overall adjusted POR (95% CI) for the ETS-periodontitis association as 1.09 (0.95-1.26) with a confidence limit ratio (CLR) of 1.34. This association varied in magnitude by Hispanic/Latino background, ranging from 1.04 (0.75, 1.43 with a CLR = 1.91) among Central Americans to 1.76 (1.16, 2.66 with a CLR = 2.29) in Puerto Ricans.

CONCLUSIONS

Previously reported associations between ETS and periodontitis appear weak in this study. However, the magnitude of the association differs according to Hispanic/Latino background.

Obesity, Inflammation, and Periodontal Disease

The prevalence of obesity has increased substantially over the past decades in most industrialized countries. Obesity is a systemic disease that predisposes to a variety of co-morbidities and complications that affect overall health. Cross-sectional studies suggest that obesity is also associated with oral diseases, particularly periodontal disease, and prospective studies suggest that periodontitis may be related to cardiovascular disease. The possible causal relationship between obesity and periodontitis and potential underlying biological mechanisms remain to be established; however, the adipose tissue actively secretes a variety of cytokines and hormones that are involved in inflammatory processes, pointing toward similar pathways involved in the pathophysiology of obesity, periodontitis, and related inflammatory diseases. We provide an overview of the definition and assessment of obesity and of related chronic diseases and complications that may be important in the periodontist’s office. Studies that have examined the association between obesity and periodontitis are reviewed, and adipose-tissue-derived hormones and cytokines that are involved in inflammatory processes and their relationship to periodontitis are discussed. Our aim is to raise the periodontist’s awareness when treating obese individuals.

Relationship between Metabolic Syndrome Components and Periodontal Disease in a Japanese General Population: the Suita Study

Aim: A positive association between metabolic syndrome (MetS) and periodontal status has recently been noted. However, no study has evaluated the relationship by sex and in a general urban population using the uniform definition proposed in the 2009 Joint Interim Statement. The aim of this study was to clarify the relationship between MetS and periodontal status using the uniform definition in a general urban Japanese population.

Methods: A total of 1,856 Japanese men and women (mean age: 66.4 years) were studied using data from the Suita study. Periodontal status was evaluated by the Community Periodontal Index (CPI). MetS was defined using the 2009 Joint Interim Statement. The associations of the MetS and its components with periodontal disease were investigated using multiple logistic regression analysis adjusting for age, drinking, and smoking.

Results: Among the components of the MetS, low HDL cholesterol level was significantly associated with periodontal disease in men and women [odds ratios (OR) = 2.39 and 1.53; 95% confidence intervals = 1.36–4.19 and 1.06–2.19]. Furthermore, the risk of periodontal disease showed 1.43-, 1.42-, and 1.89-fold increases in those with 2, 3, and ≥ 4 components, respectively, compared with those having no components (P_trend < 0.001). For the analysis by sex, the risk of periodontal disease was increased 2.27- and 1.76-fold in those with ≥ 4 components in men and women, respectively (both P_trend = 0.001).

Conclusion: These findings suggest that MetS and lower HDL cholesterol are associated with periodontal disease. Subjects with two or more MetS components had a significantly higher prevalence of periodontal disease.

Relationship between Metabolic Syndrome and Number of Teeth in Japan

The 2004 Japanese National Health and Nutrition Survey collected data on several measures, including self-reported dental health. In addition, this was the first nationwide survey to focus on metabolic syndrome (MetS) in Japan. Therefore, the authors used this nationwide data set to assess the relationship between number of teeth present and MetS. Anonymized data were available with permission from the Ministry of Health, Labour and Welfare of Japan. Data from 3,195 men and women aged 35 to 99 y were examined, and logistic regression analyses were used to evaluate the association between number of teeth and MetS. Moreover, the authors performed an analysis of covariance to compare the mean number of teeth between those with and those without MetS, after adjusting for confounders. In comparison with those having ≥28 teeth, those with fewer remaining teeth demonstrated significantly higher odds of having MetS. Specifically, those having 1 to 9 teeth had higher odds of having MetS than those with more teeth and were more than twice as likely to be affected than those with ≥28 teeth. Furthermore, individuals with MetS in the age groups of 45 to 54, 55 to 64, and 65 to 74 y had significantly fewer teeth than those without MetS in the same age groups. These results suggest that the number of teeth present is associated with the prevalence of MetS in the Japanese population. Knowledge Transfer Statement: The results of this study can be used by clinicians when they examine patients with periodontal disease or extensive tooth loss to refer for a general medical examination.

The increased ratio of 11β-hydroxysteroid dehydrogenase type 1 versus 11β-hydroxysteroid dehydrogenase type 2 in chronic periodontitis irrespective of obesity

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which converts inactive cortisone to active cortisol, has been reported to play an important role in metabolic diseases as well as chronic inflammatory diseases. The involvement of 11β-HSD1 in chronic periodontitis was investigated in the present study. The relationship between the levels of 11β-HSD1, chronic periodontitis, and body mass index (BMI) was analyzed. The expression of 11β-HSD1 mRNA was significantly higher in the chronic periodontitis group than in the control group. Since the expression of 11β-HSD2, which converts active cortisol to inactive cortisone, was slightly lower in the chronic periodontitis group than in the controls, the ratio of 11β-HSD1 versus 11β-HSD2 was significantly higher in the chronic periodontitis group than in the controls. A correlation was not observed between BMI and the level of 11β-HSD1 or between BMI and the ratio of 11β-HSD1 versus 11β-HSD2. These results suggested that an increase in the ratio of 11β-HSD1 versus 11β-HSD2 was associated with chronic periodontitis irrespective of obesity.

Possible Involvement of Palmitate in Pathogenesis of Periodontitis

Type 2 diabetes (T2D) is characterized by decreased insulin sensitivity and higher concentrations of free fatty acids (FFAs) in plasma. Among FFAs, saturated fatty acids (SFAs), such as palmitate, have been suggested to promote inflammatory responses. Although many epidemiological studies have shown a link between periodontitis and T2D, little is known about the clinical significance of SFAs in periodontitis. In this study, we showed that gingival fibroblasts have cell-surface expression of CD36, which is also known as FAT/fatty acid translocase. Moreover, CD36 expression was increased in gingival fibroblasts of high-fat diet-induced T2D model mice, compared with gingival fibroblasts of mice fed a normal diet. DNA microarray analysis revealed that palmitate increased mRNA expression of pro-inflammatory cytokines and chemokines in human gingival fibroblasts (HGF). Consistent with these results, we confirmed that palmitate-induced interleukin (IL)-6, IL-8, and CXCL1 secretion in HGF, using a cytokine array and ELISA. SFAs, but not an unsaturated fatty acid, oleate, induced IL-8 production. Docosahexaenoic acid (DHA), which is one of the omega-3 polyunsaturated fatty acids, significantly suppressed palmitate-induced IL-6 and IL-8 production. Treatment of HGF with a CD36 inhibitor also inhibited palmitate-induced pro-inflammatory responses. Finally, we demonstrated that Porphyromonas gingivalis (P.g.) lipopolysaccharide and heat-killed P.g. augmented palmitate-induced chemokine secretion in HGF. These results suggest a potential link between SFAs in plasma and the pathogenesis of periodontitis.

A study to assess the periodontal status of 16-34-year-old obese individuals in colleges of Bangalore city

Introduction:

The prevalence of obesity has increased substantially over the past decades. Age, genetic factors, activity level, body weight, eating habits, medications, and hereditary factors are some of the causes of obesity. It is a risk factor for several chronic health conditions, as well as being associated with increased mortality. Obesity has also been associated with oral diseases, particularly with periodontal disease.

Objective:

The objective was to assess the periodontal status of obese and nonobese young individuals in colleges of Bangalore city.

Materials and Methods:

A cross-sectional study was undertaken to assess the periodontal status of 16–34-year-old obese individuals in colleges of Bangalore City. The students and staff of preuniversity and Degree Colleges of Bangalore City aged below 35 years were considered in the study. Data regarding demographic factors, oral hygiene habits, and dental visits were collected through a questionnaire. Periodontal status was examined using community periodontal index (CPI). Subjects were examined for weight and height as well as periodontal status.

Results:

It was observed that pocket 4–5 mm (CPI Code 3) is significantly higher among obese when compared to nonobese with P < 0.001 and loss of attachment 4–5 mm (Loss of Attachment Code 1) is significantly higher in obese when compared to nonobese with P < 0.001.

Conclusion:

The results described earlier and related research indicate that obesity may have potential for periodontal disease among young and/or those lacking oral health care.

Change of periodontal inflammatory indicators through a 4-week weight control intervention including caloric restriction and exercise training in young Koreans: a pilot study

BACKGROUND

Recent cross-sectional studies indicate that obesity is a risk factor for periodontal disease. Exercise training in high fat mice or rats can inhibit gingival inflammation effectively. The objective of this human intervention study was to investigate whether short-term weight control could affect periodontal indexes and serum and gingival crevicular fluid (GCF) biomarkers in young Koreans.

METHODS

Forty-one obese volunteers (body mass index (BMI) > 25.0) and 12 normal weight subjects (18.5 ≤ BMI ≤ 23.0) participated in a four-week weight control program to analyze the changes in anthropometric criteria, the concentrations of C-reactive protein (CRP), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides in serum, gingival index, bleeding on probing, periodontal biomarkers in GCF, and dental plaque index at the first and the 27th days.

RESULTS

The means of obesity measures decreased significantly more in the obese group (BMI 2.53 ± 0.96, waist-to-hip ratio (WHR) 4.88 ± 1.58 %, LDL 35.85 ± 21.74 mgdL(-1)) than in the normal weight group (BMI 0.78 ± 0.72, WHR 2.00 ± 0.95 %, LDL 15.58 ± 18.07 mgdL(-1)). While the obese group showed significant decreases in the biomarkers in GCF (IL-1β 58.38 ± 65.55 pgmL(-1), MMP-8 4.19 ± 5.61 ngmL(-1), MMP-9 3.36 ± 6.30 ngmL(-1)), the mean changes for the normal weight group (IL-1β 10.07 ± 21.08 pgmL(-1), MMP-8 1.49 ± 4.61 ngmL(-1), MMP-9 -1.52 ± 9.71 ngmL(-1)) were not statistically significant. Anthropometric measures and the amounts of GCF biomarkers had weak positive correlations (0.242 ≤ r ≤ 0.340), and LDL in serum correlated with MMP-8 (r = 0.332) and IL-1β (r = 0.342) in the obese group. Stepwise multiple linear regression analysis in the obese group showed that the relationship between the amount of IL-1β in GCF and predictor variables including LDL and BMI was highly significant and accounted for 19.1 % of the variance in IL-1β in GCF.

CONCLUSIONS

In periodontally healthy subjects, weight control could reduce the amounts of MMP-8, MMP-9, and IL-1β in GCF of the obese subjects. Further studies with periodontally unhealthy and obese people are needed to identify the mechanism of decreases in inflammation biomarkers in GCF through weight control.

TRIAL REGISTRATION

ISRCTN86753073 (2015.08.14).

Host response, obesity, and oral health

Proper food choices are part of preventing or reducing the risk of dental caries and periodontal disease. A significant association has been proven between oral diseases and the incidence of systemic diseases. Obesity, just like smoking, is one of the major risk factors for oral disease and is a serious social problem that has reached epidemic proportions in many developed countries. The results of studies on periodontitis confirm the relationship between the values of body mass index (BMI) and the prevalence of periodontal diseases. Adipose tissue is an active endocrine organ and it performs many important functions in the body, such as thermal isolation and protection, storage, and secretion. Many cytokines are secreted proportionally to the amount of fat present and are actively involved in the metabolism of the whole system, including the functioning of the immune system. Therefore, obesity may alter the response of the host to the antigens derived from bacterial plaque, and thus cause disturbances in the inflammatory response in the course of periodontal disease.

Bias in estimating the cross-sectional smoking, alcohol, obesity and diabetes associations with moderate-severe periodontitis in the Atherosclerosis Risk in Communities study: comparison of full versus partial-mouth estimates

OBJECTIVE

To assess whether partial-mouth protocols (PRPs) result in biased estimates of the associations between smoking, alcohol, obesity and diabetes with periodontitis.

METHODS

Using a sample (n = 6129) of the 1996-1998 Atherosclerosis Risk in Communities study, we used measures of probing pocket depth and clinical attachment level to identify moderate-severe periodontitis. Adjusting for confounders, unconditional binary logistic regression estimated prevalence odds ratios (POR) and 95% confidence limits. Specifically, we compared POR for smoking, alcohol, obesity and diabetes with periodontitis derived from full-mouth to those derived from 4-PRPs (Ramfjörd, National Health and Nutrition Examination survey-III, modified-NHANES-IV and 42-site-Random-site selection-method). Finally, we conducted a simple sensitivity analysis of periodontitis misclassification by changing the case definition threshold for each PRP.

RESULTS

In comparison to full-mouth PORs, PRP PORs were biased in terms of magnitude and direction. Holding the full-mouth case definition at moderate-severe periodontitis and setting it at mild-moderate-severe for the PRPs did not consistently produce POR estimates that were either biased towards or away from the null in comparison to full-mouth estimates.

CONCLUSIONS

Partial-mouth protocols result in misclassification of periodontitis and may bias epidemiologic measures of association. The magnitude and direction of this bias depends on choice of PRP and case definition threshold used.

Pathological periodontal pockets are associated with raised diastolic blood pressure in obese adolescents

BACKGROUND

Obesity, a well-known risk factor for developing cardiovascular disease (CVD), is associated with chronic periodontitis in adults. This cross-sectional pilot study on obese adolescents was designed to investigate whether periodontal disease in terms of pathological periodontal pockets is associated with raised blood pressure and other risk markers for CVD.

METHODS

The study included 75 obese subjects between 12 to 18 years of age, mean 14.5. Subjects answered a questionnaire regarding health, oral hygiene habits and sociodemographic factors. A clinical examination included Visible Plaque Index (VPI %), Gingival inflammation (BOP %) and the occurrence of pathological pockets exceeding 4 mm (PD ≥ 4 mm). Blood serum were collected and analyzed. The systolic and diastolic blood pressures were registered.

RESULTS

Adolescents with pathological periodontal pockets (PD ≥ 4 mm; n = 14) had significantly higher BOP >25% (P = 0.002), higher diastolic blood pressure (P = 0.008), higher levels of Interleukin (IL)-6 (P < 0.001), Leptin (P = 0.018), Macrophage Chemoattractant Protein-1 (MCP-1) (P = 0.049) and thyroid stimulating hormone (TSH) (P = 0.004) in blood serum compared with subjects without pathological periodontal pockets (PD ≥ 4 mm; n = 61). The bivariate linear regression analysis demonstrated that PD ≥ 4 mm (P = 0.008) and systolic blood pressure (P < 0.001) were significantly associated with the dependent variable "diastolic blood pressure". The association between PD ≥ 4 mm and diastolic blood pressure remained significant (P = 0.006) even after adjusting for potential confounders BMI-sds, age, gender, mother's country of birth, BOP >25%, IL-6, IL-8, Leptin, MCP-1, TSH and total cholesterol in the multiple regression analysis.

CONCLUSION

In conclusion, this study indicates an association between pathological periodontal pockets and diastolic blood pressure in obese adolescents. The association was unaffected by other risk markers for cardiovascular events or periodontal disease. The results call for collaboration between pediatric dentists and medical physicians in preventing obesity development and its associated disorders.

Effect of non-surgical periodontal treatment on visfatin concentrations in serum and gingival crevicular fluid of patients with chronic periodontitis and type 2 diabetes mellitus

BACKGROUND

This study aims to assess visfatin concentrations in serum and gingival crevicular fluid (GCF) and investigate this relationship in patients with type 2 diabetes mellitus (T2DM) and chronic periodontitis (CP) before and after non-surgical periodontal treatment.

METHODS

Fifty-four patients with T2DM and CP were recruited. The patients were randomly divided into two groups: treatment and control. Serum and GCF visfatin concentrations and glycated hemoglobin (HbA1c) levels were measured by enzyme-linked immunosorbent assay at different time points (at baseline and 3 and 6 months after non-surgical periodontal treatment).

RESULTS

Serum and GCF visfatin concentrations showed no significant differences between the groups at baseline (t test, P >0.05). A significant decline of visfatin in the treatment group was found in serum and GCF 3 months after non-surgical periodontal treatment (t test, P <0.01). Baseline and 3-month HbA1c levels were not significantly different, but at 6 months, a statistically significant difference was detected (t test, P >0.05).

CONCLUSIONS

The data suggest that non-surgical periodontal treatment is helpful for glucose control, an effect that may be associated with reduced visfatin in patients with T2DM and periodontitis. Furthermore, the data suggest that visfatin may be considered an inflammatory marker for periodontal diseases.

Longitudinal relationship between metabolic syndrome and periodontal disease among Japanese adults aged ≥70 years: the Niigata Study

BACKGROUND

There has been little evaluation in longitudinal epidemiologic studies of the effect of metabolic syndrome (MetS) on periodontal status. The specific aim of this longitudinal study is to investigate whether MetS in the Japanese population could be a risk factor for periodontal disease.

METHODS

A total of 125 older adults from Japan for whom data were available for the years 2003 to 2006 were selected for the current study. Full-mouth periodontal status, measured as clinical attachment level (CAL), was recorded at baseline and in follow-up examinations. Development of periodontal disease was considered to be ≥2 teeth demonstrating a longitudinal loss of proximal attachment of ≥3 mm at the follow-up dental examination. A multivariable Poisson regression model with robust error variance was used to evaluate the association of MetS defined by the modified National Cholesterol Education Program Adult Treatment Panel III criteria with development of periodontal disease. Adjustments for sex, income, education, smoking status, number of teeth at baseline, mean CAL at baseline, pattern of visits to a dentist, and brushing frequency were considered.

RESULTS

The prevalence of MetS was 21.6% (27/125). Study participants with MetS were approximately 2.6 times more likely to develop periodontal disease (adjusted relative risk 2.58, 95% confidence interval 1.17 to 5.67) after simultaneous adjustment for other covariates.

CONCLUSIONS

These findings support the hypothesis that MetS may be a risk factor for periodontal disease in older Japanese individuals. Additional studies with larger, more diverse populations and more complete information are needed to substantiate the findings.

The interaction between beta-3 adrenergic receptor polymorphism and obesity to periodontal disease in community-dwelling elderly Japanese

OBJECTIVES

The purpose of this study was to elucidate whether the association between beta-3 adrenergic receptor polymorphism and periodontal disease is modified by body weight.

MATERIAL AND METHODS

We enrolled 332 postmenopausal women and determined their HbA1C levels (%) and beta-3 adrenergic receptor (rs4994) genotypes. Periodontal parameters including clinical attachment level (CAL) were measured. After selecting subjects for each body mass index (BMI) level, the prevalence rate ratio (PRR) by multiple Poisson regression analysis was calculated to evaluate the relationship between periodontal disease and beta-3 adrenergic receptor polymorphism. The number of sites with CAL≥6 mm was used as a dependent variable, and beta-3 adrenergic receptor genotype [categorized as Arg non-carriers (reference) or Arg carriers], age (y) and HbA1C (%) were adopted as independent variables. We converted the number of probing sites (n) to an offset variable.

RESULTS

The PRR of the beta-3 adrenergic receptor genotype for the number of sites of CAL≥6 mm showed a positive association in subjects with BMI≥25.0 and increased markedly with BMI. The PRR in subjects with BMI≥30 was 3.10 (p < 0.0001).

CONCLUSION

This study indicates a positive association between periodontal disease and the beta-3 adrenergic receptor genotype in obese individuals.

The role of adipokines in periodontal infection and healing

Periodontitis is a chronic inflammatory disease of the periodontium, which is caused by pathogenic bacteria in combination with other risk factors. The bacteria induce an immunoinflammatory host response, which can lead to irreversible matrix degradation and bone resorption. Periodontitis can be successfully treated. To achieve regenerative periodontal healing, bioactive molecules, such as enamel matrix derivative (EMD), are applied during periodontal surgery. Recently, it has been shown that obesity is associated with periodontitis and compromised healing after periodontal therapy. The mechanisms underlying these associations are not well understood so far, but adipokines may be a pathomechanistic link. Adipokines are bioactive molecules that are secreted by the adipose tissue, and that regulate insulin sensitivity and energy expenditure, but also inflammatory and healing processes. It has also been demonstrated that visfatin and leptin increase the synthesis of proinflammatory and proteolytic molecules, whereas adiponectin downregulates the production of such mediators in periodontal cells. In addition, visfatin and leptin counteract the beneficial effects of EMD, whereas adiponectin enhances the actions of EMD on periodontal cells. Since visfatin and leptin levels are increased and adiponectin levels are reduced in obesity, these adipokines could be a pathomechanistic link whereby obesity and obesity-related diseases enhance the risk for periodontitis and compromised periodontal healing. Recent studies have also revealed that adipokines, such as visfatin, leptin and adiponectin, are produced in periodontal cells and regulated by periodontopathogenic bacteria. Therefore, adipokines may also represent a mechanism whereby periodontal infections can impact on systemic diseases.

Oral pathobiont induces systemic inflammation and metabolic changes associated with alteration of gut microbiota

Periodontitis has been implicated as a risk factor for metabolic disorders such as type 2 diabetes, atherosclerotic vascular diseases, and non-alcoholic fatty liver disease. Although bacteremias from dental plaque and/or elevated circulating inflammatory cytokines emanating from the inflamed gingiva are suspected mechanisms linking periodontitis and these diseases, direct evidence is lacking. We hypothesize that disturbances of the gut microbiota by swallowed bacteria induce a metabolic endotoxemia leading metabolic disorders. To investigate this hypothesis, changes in the gut microbiota, insulin and glucose intolerance, and levels of tissue inflammation were analysed in mice after oral administration of Porphyromonas gingivalis, a representative periodontopathogens. Pyrosequencing revealed that the population belonging to Bacteroidales was significantly elevated in P. gingivalis-administered mice which coincided with increases in insulin resistance and systemic inflammation. In P. gingivalis-administered mice blood endotoxin levels tended to be higher, whereas gene expression of tight junction proteins in the ileum was significantly decreased. These results provide a new paradigm for the interrelationship between periodontitis and systemic diseases.

Obesity and cumulative inflammatory burden: a valuable risk assessment parameter in caring for dental patients

A new model of risk assessment that recognizes the importance of reducing patients' cumulative inflammatory burden by targeting overweight and obesity, in individuals with periodontal disease, may be a valuable risk assessment parameter in caring for dental patients.

BACKGROUND

The growing body of evidence that suggests obesity, Metabolic Syndrome and periodontal disease are interrelated offers an unprecedented opportunity to adopt a new model of risk assessment that has the potential to beneficially influence not only the periodontal health of obese and overweight patients, but simultaneously may also reduce a person's overall risk for developing heart disease and type 2 diabetes, and perhaps other inflammatory driven disease states.

METHODS

This paper presents an overview of research that builds the case for a new model of risk assessment that focuses on the cumulative inflammatory burden that may be elevated by the presence of periodontal disease in obese patients. In addition, the biological plausibility of the concepts of inflammatory priming and inflammatory loading is discussed, and several simple ideas are suggested for identifying at-risk patients.

CONCLUSIONS

Given the significant rise in obesity and the impact that obesity has on periodontal health and other inflammatory driven, systemic disease states, adoption of a new model of risk assessment is suggested-one that considers an individual's cumulative inflammatory burden which may be amplified as a result of coexisting obesity and other components of Metabolic Syndrome and periodontal disease. Knowledge gathered thus far combined with further clinical research must be translated into better ways to treat and maintain obese periodontal patients. These measures may pave the way for prevention of metabolic diseases and obesity with a relevant impact on patients' periodontal status.

The relationship between body mass index and body fat percentage and periodontal status in Mexican adolescents

OBJECTIVE

To assess the association between obesity indicators and the periodontal status of high school students.

MATERIALS AND METHODS

High school students (15-year-olds) in Mexico City participated in the survey (n = 257). International Obesity Task Force cut-off values (ISO-BMI) were applied to identify overweight and obesity. Also, bioelectrical impedance analysis was performed to estimate body fat percentage (BF%). The simplified detritus index (DI-S) was used to evaluate oral hygiene. The periodontal community index (CPI) was obtained to assess the periodontal status of the participants.

RESULTS

Overweight/obesity was identified in 30.0% of the students. BF% was 37.5% in women and 21.2% in men and 16.7% of the participants smoked and 33.5% of the students presented DI-S >1. Based on CPI, 59.5% of the participants showed good periodontal status (CPI = 0); bleeding on probing without further periodontal involvement was found in 13.6% of the participants (CPI = 1), 23.8% showed a CPI = 2 (dental calculus) and a CPI = 3 (shallow periodontal pockets) was detected in 3.1% of the participants. The results of the multinomial logistical regression model fitting CPI ≥2 identified an association BF% (OR = 1.06), having poor oral hygiene (OR = 20.09) and smoking (OR = 2.49). Similarly, overweight/obesity was associated with CPI ≥2 (OR = 1.78) adjusting for school attended (public school OR = 0.35), oral hygiene (DI-S >1, OR = 23.92) and tobacco consumption (smoker OR = 1.81).

CONCLUSIONS

Excess body fat indicators were associated with bleeding on probing and dental calculus in adolescents. The relationship between overweight/obesity and periodontal status in adolescents should be considered in oral health preventive programs.

Periodontal care as a fundamental step for an active and healthy ageing

In the industrialized part of the world, an increasing number of people live the old age without too many restrictions due to illness or physiological impairment. This group is known as the young elderly. On the contrary, a consistent part of seniors develops a greater number of medical conditions and become more and more dependent, these are the old elderly. The first cause of tooth lost in industrialized word is periodontitis that generally strikes people older than 40 years and determines serious detriment of the stomatognatic organ. Smoking and stress are risk factors for periodontitis that are common and shared between young, adult, and older age. Diabetes mellitus, obesity, and osteoporosis are very frequent pathological situations in older age. They have been identified as cofactors in the progression of periodontitis. Many dental associations recognize the importance of continued research on oral fluids diagnostics and welcome the development of rapid point-of-care tests providing accurate measurements of clinically validated biomarkers. At present, well-studied molecules associated with host response factors and with derived tissue destruction mediators have been proposed as diagnostic biomarkers for periodontitis detected in the oral fluids.

Is obesity a possible modifier of periodontal disease as a chronic inflammatory process? A case-control study

BACKGROUND AND OBJECTIVE

This cross-sectional case-control study was conducted to provide a comparative evaluation of clinical periodontal measurements, together with serum levels of certain bioactive peptides and inflammatory cytokines, in relation to obesity. For this purpose, clinical periodontal measurements and the levels of serum leptin, adiponectin, interleukin-6 (IL-6), C-reactive protein and soluble intercellular adhesion molecule-1 of obese female individuals and their nonobese counterparts were compared.

MATERIAL AND METHODS

Sixty obese (body mass index (BMI) > 30) and 31 nonobese (BMI < 30) female subjects were recruited for the present study. Before any periodontal intervention, serum samples were obtained and full-mouth clinical periodontal measurements were recorded at six sites per tooth. ELISA was used for the biochemical analysis. Data were tested statistically.

RESULTS

Clinical attachment level was significantly higher in the obese group compared with the nonobese control group (p < 0.05). Serum levels of leptin and IL-6 were significantly higher in the obese group (p < 0.05). BMI correlated with the serum levels of inflammatory molecules (p < 0.05), but not with clinical periodontal parameters, in the obese group.

CONCLUSION

In conclusion, obesity does not seem to have a prominent effect on clinical periodontal parameters but it does have many correlations with circulating inflammatory molecules. As suggested in the literature, increased levels of leptin and IL-6 in the obese group might be one explanation for a possible relationship between obesity and periodontal disease. A prospective study is warranted to clarify, in greater detail, the effects of obesity on periodontal health.

Periodontal innate immune mechanisms relevant to obesity

Obesity affects over 35% of the adult population of the USA, and obesity-related illnesses have emerged as the leading cause of preventable death worldwide, according to the World Health Organization. Obesity's secondary morbidities include increased risk of cardiovascular disease, type II diabetes, and cancer, in addition to increased occurrence and severity of infections. Sedentary lifestyle and weight gain caused by consumption of a high-fat diet contribute to the development of obesity, with individuals having a body mass index (BMI) score > 30 being considered obese. Genetic models of obesity (ob/ob mice, db/db mice, and fa/fa rats) have been insufficient to study human obesity because of the overall lack of genetic causes for obesity in human populations. To date, the diet-induced obese (DIO) mouse model best serves research studies relevant to human health. Periodontal disease presents with a wide range of clinical variability and severity. Research in the past decade has shed substantial light on both the initiating infectious agents and host immunological responses in periodontal disease. Up to 46% of the general population harbors the microorganism(s) associated with periodontal disease, although many are able to limit the progression of periodontal disease or even clear the organism(s) if infected. In the last decade, several epidemiological studies have found an association between obesity and increased incidence of periodontal disease. This review focuses on exploring the immunological consequences of obesity that exacerbate effects of infection by pathogens, with focus on infection by the periodontal bacterium Porphyromonas gingivalis as a running example.

Predictive, preventive, personalised and participatory periodontology: 'the 5Ps age' has already started

An impressive progress in dentistry has been recorded in the last decades. In order to reconsider guidelines in dentistry, it is required to introduce new concepts of personalised patient treatments: the wave of predictive, preventive and personalised medicine is rapidly incoming in dentistry. Worldwide dentists have to make a big cultural effort in changing the actual 'reactive' therapeutic point of view, belonging to the last century, into a futuristic 'predictive' one. The first cause of tooth loss in industrialised world is periodontitis, a Gram-negative anaerobic infection whose pathogenesis is genetically determined and characterised by complex immune reactions. Chairside diagnostic tests based on saliva, gingival crevicular fluid and cell sampling are going to be routinely used by periodontists for a new approach to the diagnosis, monitoring, prognosis and management of periodontal patients. The futuristic '5Ps' (predictive, preventive, personalised and participatory periodontology) focuses on early integrated diagnosis (genetic, microbiology, host-derived biomarker detection) and on the active role of the patient in which networked patients will shift from being mere passengers to responsible drivers of their health. In this paper, we intend to propose five diagnostic levels (high-tech diagnostic tools, genetic susceptibility, bacterial infection, host response factors and tissue breakdown-derived products) to be evaluated with the intention to obtain a clear picture of the vulnerability of a single individual to periodontitis in order to organise patient stratification in different categories of risk. Lab-on-a-chip (LOC) technology may soon become an important part of efforts to improve worldwide periodontal health in developed nations as well as in the underserved communities, resource-poor areas and poor countries. The use of LOC devices for periodontal inspection will allow patients to be screened for periodontal diseases in settings other than the periodontist practice, such as at general practitioners, general dentists or dental hygienists. Personalised therapy tailored with respect to the particular medical reality of the specific stratified patient will be the ultimate target to be realised by the 5Ps approach. A long distance has to be covered to reach the above targets, but the pathway has already been clearly outlined.

Obesity may increase the occurrence of spontaneous periodontal disease in Wistar rats

OBJECTIVE

To evaluate the effect of body weight on the occurrence of spontaneous alveolar bone loss in Wistar rats.

METHODS

Twenty-eight rats were randomly divided in two groups. Control group received standardized rat chow diet and water. Test group received cafeteria (CAF) diet during 17 weeks. Diet was available for both groups ad libitum. Body weight and Lee Index were evaluated. At the end of the experimental period, rats were killed by decapitation and maxillae were defleshed with 9% sodium hypochlorite. Morphometric analysis was performed in digital standard photographs. Presence of spontaneous periodontitis was considered when mean alveolar bone loss was ≥0.51mm (75th percentile). Statistical analysis was performed with chi-square test, Mann-Whitney test and independent samples t-test (significance level P≤0.05).

RESULTS

After 17 weeks of exposure to standard CAF diet, a statistically significant mean difference in body weight (g±SD) (478±43 vs. 580±60) and Lee Index (3.07±0.05 vs. 3.24±0.07) was observed between control and obesity groups, respectively. Median (interquartile range) of alveolar bone loss in control group was 0.344 (0.313-0.367) and 0.491 (0.427-0.506) for buccal and palatal site, respectively. For obese group was 0.308 (0.289-0.354) and 0.549 (0.482-0.616) for buccal and palatal site, respectively. In animals submitted to CAF diet, 20 sites were classified as spontaneous periodontal disease, whereas in control animals, only 8 sites exhibited periodontal breakdown according cut-off point. A significant difference between groups was detected (P=0.009).

CONCLUSIONS

It may be concluded that obesity increases the occurrence of spontaneous periodontal disease in Wistar rats.

Exploring the genetic basis of chronic periodontitis: a genome-wide association study

Chronic periodontitis (CP) is a common oral disease that confers substantial systemic inflammatory and microbial burden and is a major cause of tooth loss. Here, we present the results of a genome-wide association study of CP that was carried out in a cohort of 4504 European Americans (EA) participating in the Atherosclerosis Risk in Communities (ARIC) Study (mean age—62 years, moderate CP—43% and severe CP—17%). We detected no genome-wide significant association signals for CP; however, we found suggestive evidence of association (P < 5 × 10⁻⁶) for six loci, including NIN, NPY, WNT5A for severe CP and NCR2, EMR1, 10p15 for moderate CP. Three of these loci had concordant effect size and direction in an independent sample of 656 adult EA participants of the Health, Aging, and Body Composition (Health ABC) Study. Meta-analysis pooled estimates were severe CP (n = 958 versus health: n = 1909)—NPY, rs2521634 [G]: odds ratio [OR = 1.49 (95% confidence interval (CI = 1.28–1.73, P = 3.5 × 10⁻⁷))]; moderate CP (n = 2293)—NCR2, rs7762544 [G]: OR = 1.40 (95% CI = 1.24–1.59, P = 7.5 × 10⁻⁸), EMR1, rs3826782 [A]: OR = 2.01 (95% CI = 1.52–2.65, P = 8.2 × 10⁻⁷). Canonical pathway analysis indicated significant enrichment of nervous system signaling, cellular immune response and cytokine signaling pathways. A significant interaction of NUAK1 (rs11112872, interaction P = 2.9 × 10⁻⁹) with smoking in ARIC was not replicated in Health ABC, although estimates of heritable variance in severe CP explained by all single nucleotide polymorphisms increased from 18 to 52% with the inclusion of a genome-wide interaction term with smoking. These genome-wide association results provide information on multiple candidate regions and pathways for interrogation in future genetic studies of CP.

Association between obesity and chronic periodontitis: a cross-sectional study

AIM

Chronic periodontitis is multifactorial and numerous risk factors have been identified to contribute in the disease progression. Current study aimed to conduct a cross-sectional study in a population of patients with cardiovascular diseases in order to correlate the association between obesity [body mass index (BMI) and waist circumference (WC)] and periodontal disease parameters.

MATERIALS AND METHODS

The study was of a cross-sectional design and a total of 201 patients were examined after obtaining their informed consent. Subjects who had a history of cardiovascular diseases and under treatment were included in the study. Two indicators of obesity were used: BMI and WC. The following periodontal parameters were assessed: Probing depth, clinical attachment level. The oral hygiene status of the subjects was assessed by the oral hygiene index (OHI, simplified) given by John C Greene and Jack R Vermillion. The influence of the BMI and other confounding variables on periodontitis severity was assessed by multivariate logistic regression analysis. Data were analyzed using SPSS.

RESULTS

Significant association was seen with low density lipoproteins (LDL) and severity of periodontitis (p < 0.005), triglyceride levels (TGL) and severity of periodontitis (p < 0.005), cholesterol and severity of periodontitis (p < 0.005), BMI and severity of periodontitis (p < 0.001), OHI and severity of periodontitis (p < 0.001). Significant association was seen with smoking and severity of periodontitis (p < 0.005), BMI and severity of periodontitis (p < 0.001), WC and severity of periodontitis (p < 0.001), cholesterol and severity of periodontitis (p < 0.001), OHI and severity of periodontitis (p < 0.001).

CONCLUSION

Obesity has been implicated as a risk factor for several conditions including cardiovascular disease, diabetes, etc. In our study the relation between measures of overall and abdominal obesity (BMI and WC) and periodontal disease showed significant association in the multivariate logistic regression analysis independent of other confounding factors.

CLINICAL SIGNIFICANCE

Obesity can act as a significant risk factor in progression of periodontitis.

Periodontitis as a novel contributor of adipose tissue inflammation promotes insulin resistance in a rat model

BACKGROUND

Recent studies have indicated that the chronic low-grade inflammation induced by periodontitis is related to obesity and type 2 diabetes mellitus. The purpose of this study is to investigate the effects of periodontitis on obesity-related adipose tissue inflammation and subsequent systemic insulin resistance in a rat model.

METHODS

Thirty-two rats were divided into four groups of eight: 1) obese rats with periodontitis (combination group); 2) obese rats without periodontitis (obesity group); 3) normal rats with periodontitis (periodontitis group); and 4) normal rats without periodontitis (control group). Monosodium glutamate was used to induce obesity during the early postnatal period. Periodontitis was induced by ligatures for 8 weeks. Morphologic features of white adipose tissue (WAT) and islets were observed, and fasting plasma glucose and insulin concentrations and homeostasis model assessment for insulin (HOMA-IR) were measured at 5 months. Differences among groups were compared with the Fisher post hoc least significant difference test.

RESULTS

A slight increase of stromal vascular fractions (SVFs) and macrophage infiltration in the WAT of the periodontitis group was observed. Significant proliferation of SVFs and macrophage infiltration were induced in the combination group. HOMA-IR scores in the combination and periodontitis groups were higher than in the obesity and control groups, respectively. The disturbance of islet architecture was consistent with a high HOMA-IR score in the combination group.

CONCLUSIONS

Periodontitis induced initial stages of WAT inflammation and acted as a contributing factor to exacerbate proinflammatory phenotype of WAT and promote the development of insulin resistance in the obese rat model.

Obesity and the risk and outcome of infection

The interactions between obesity and infectious diseases have recently received increasing recognition as emerging data have indicated an association between obesity and poor outcome in pandemic H1N1 influenza infection. Obesity is an established risk factor for surgical-site infections, nosocomial infections, periodontitis and skin infections. Several studies indicate that acute pancreatitis is more severe in the obese. Data are controversial and limited as regards the association between obesity and the risk and outcome of community-acquired infections such as pneumonia, bacteremia and sepsis and obesity and the course of HIV infection. As the cause-effect relationship between obesity and infection remains obscure in many infectious diseases, further studies are warranted. The consequences of obesity may have substantial effects on the global burden of infectious diseases.

Adiponectin regulates functions of gingival fibroblasts and periodontal ligament cells

BACKGROUND AND OBJECTIVE

Adiponectin is a cytokine constitutively produced by adipocytes and exhibits multiple biological functions by targeting various cell types. However, the effects of adiponectin on primary gingival fibroblasts and periodontal ligament cells are still unexplored. Therefore, we investigated the effects of adiponectin on gingival fibroblasts and periodontal ligament cells.

MATERIAL AND METHODS

The expression of adiponectin receptors (AdipoR1 and AdipoR2) on human gingival fibroblasts (HGFs), mouse gingival fibroblasts (MGFs) and human periodontal ligament (HPDL) cells was examined using RT-PCR and western blotting. HGFs and MGFs were stimulated with interleukin (IL)-1β in the presence or absence of adiponectin, and the expression of IL-6 and IL-8 at both mRNA and protein levels was measured by real-time PCR and ELISA, respectively. Furthermore, small interfering RNAs (siRNAs) in MGFs were used to knock down the expression of mouse AdipoR1 and AdipoR2. The effects of adiponectin on the expression of alkaline phosphatase (ALP) and runt-related transcription factor 2 (Runx2) genes were evaluated by real-time PCR. Mineralized nodule formation of adiponectin-treated HPDL cells was revealed by Alizarin Red staining.

RESULTS

AdipoR1 and AdipoR2 were expressed constitutively in HGFs, MGFs and HPDL cells. Adiponectin decreased the expression of IL-6 and IL-8 in IL-1β-stimulated HGFs and MGFs. AdipoR1 siRNA in MGFs revealed that the effect of adiponectin on reduction of IL-6 expression was potentially mediated via AdipoR1. Adiponectin-treated HPDL cells promoted the expression of ALP and Runx2 mRNAs and up-regulated ALP activity. Furthermore, adiponectin enhanced mineralized nodule formation of HPDL cells.

CONCLUSION

Our observations demonstrate that adiponectin exerts anti-inflammatory effects on HGFs and MGFs, and promotes the activities of osteoblastogenesis of HPDL cells. We conclude that adiponectin has potent beneficial functions to maintain the homeostasis of periodontal health, improve periodontal lesions, and contribute to wound healing and tissue regeneration.

Microbiota in the oral subgingival biofilm is associated with obesity in adolescence

To test the hypothesis whether microbiota in oral biofilm is linked with obesity in adolescents we designed this cross-sectional study. Obese adolescents (n = 29) with a mean age of 14.7 years and normal weight subjects (n = 58) matched by age and gender were examined with respect to visible plaque index (VPI%) and gingival inflammation (bleeding on probing (BOP%)). Stimulated saliva was collected. They answered a questionnaire concerning medical history, medication, oral hygiene habits, smoking habits, and sociodemographic background. Microbiological samples taken from the gingival crevice was analyzed by checkerboard DNA-DNA hybridization technique. The sum of bacterial cells in subgingival biofilm was significantly associated with obesity (P < 0.001). The link between sum of bacterial cells and obesity was not confounded by any of the studied variables (chronic disease, medication, VPI%, BOP%, flow rate of whole saliva, or meal frequency). Totally 23 bacterial species were present in approximately threefold higher amounts, on average, in obese subjects compared with normal weight controls. Of the Proteobacteria phylum, Campylobacter rectus and Neisseria mucosa were present in sixfold higher amounts among obese subjects. The association between obesity and sum of bacterial cells in oral subgingival biofilm indicates a possible link between oral microbiota and obesity in adolescents.

Serum plasminogen activator inhibitor-1 and tumor necrosis factor-α levels in obesity and periodontal disease

BACKGROUND

Several studies have shown a possible association between periodontal disease and obesity. The aim of this study is to evaluate serum plasminogen activator inhibitor 1 (PAI-1), tumor necrosis factor-alpha (TNF-α), and high-sensitivity C-reactive protein (hsCRP) levels in the association between obesity and periodontal disease.

METHODS

Two hundred individuals participated in this study. Body mass index (BMI), waist-to-hip ratio, plasma triglyceride (TRG), total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), hsCRP, TNF-α, PAI-1, and periodontal parameters (including plaque index [PI], probing depth [PD], clinical attachment level [CAL], and percentage of sites with bleeding on probing) were evaluated.

RESULTS

The groups with BMI ≥ 25 had higher median values for FBG, TRG, hsCRP, PAI-1, PI, and CAL than did the groups with a BMI < 25 (P <0.01). Serum TRG levels were positively correlated with PI, PD, and CAL. There were negative associations between clinical periodontal parameters and HDL-C. There were statistically significant correlations between PAI-1 and clinical periodontal parameters (PI, PD, and CAL).

CONCLUSION

Serum PAI-1 levels may play an important role in the association between periodontal disease and obesity.

Association of serum and crevicular visfatin levels in periodontal health and disease with type 2 diabetes mellitus

BACKGROUND

Levels of visfatin in serum and gingival crevicular fluid (GCF) were explored in patients with periodontal health, periodontal disease with and without type 2 diabetes mellitus (t2 DM) and were found to be elevated with periodontal disease, and were correlated with periodontal clinical parameters. DM and chronic periodontitis (CP) are associated with each other. Adipokines, specifically visfatin, are secreted from adipocytes and are thought to cause insulin resistance. The purpose of this study is to determine the presence of visfatin in serum and GCF in t2 DM among individuals with CP and to find an association, if any.

METHODS

Thirty individuals (15 males and 15 females) were selected based on their clinical parameters into three groups: group 1 (10 healthy), group 2 (10 well-controlled t2 DM among individuals with CP), and group 3 (10 individuals with CP and without diabetes). Serum and GCF samples were collected to estimate the levels of visfatin using enzyme linked immunosorbent assay.

RESULTS

The mean visfatin concentration increased in both serum and GCF in individuals with t2 DM with CP. Also, it was observed that visfatin in both serum and GCF correlated positively with all the periodontal parameters.

CONCLUSIONS

All the samples in each group tested positive for visfatin assay. Serum and GCF visfatin concentration in both t2 DM with CP and individuals with CP and without diabetes correlated positively with all the clinical parameters. Additional large-scale longitudinal studies should be performed to confirm positive correlations.

Evaluation of tumor necrosis factor-α (TNF-α) levels in plasma and their correlation with periodontal status in obese and non-obese subjects

Background:

Obesity is emerging as a significant health problem worldwide and is a risk factor for various systemic diseases. Periodontal disease is a multifactorial inflammatory disease. Recent evidence points to a link between obesity and periodontal disease, and a role for tumor necrosis factor-α (TNF-α) has been suggested.

Materials and Method:

Forty nondiabetic subjects were divided into two groups: group A (non-obese) included subjects with body mass index (BMI) of 18.5 to 27 kg/m2, and group B (obese) included subjects with BMI>27 kg/m2. The BMI, TNF-α levels in plasma and Periodontal Disease Index (PDI) scores were assessed, compared and correlated.

Results:

Significantly higher PDI scores and TNF-α levels were found in the obese group as compared to those in the non-obese group. Also, a significant and positive correlation was seen between BMI and TNF-α, TNF-α and PDI as well as BMI and PDI.

Conclusion:

Increase in the levels of tumor necrosis factor-a in plasma and an increase in the severity of periodontal disease may be seen in subjects with a higher body mass index (BMI). This indicates that obesity may be detrimental to the periodontal health of individuals.

Caloric restriction and chronic inflammatory diseases

A reduction in calorie intake [caloric restriction (CR)] appears to consistently decrease the biological rate of aging in a variety of organisms as well as protect against age-associated diseases including chronic inflammatory disorders such as cardiovascular disease and diabetes. Although the mechanisms behind this observation are not fully understood, identification of the main metabolic pathways affected by CR has generated interest in finding molecular targets that could be modulated by CR mimetics. This review describes the general concepts of CR and CR mimetics as well as discusses evidence related to their effects on inflammation and chronic inflammatory disorders. Additionally, emerging evidence related to the effects of CR on periodontal disease in non-human primates is presented. While the implementation of this type of dietary intervention appears to be challenging in our modern society where obesity is a major public health problem, CR mimetics could offer a promising alternative to control and perhaps prevent several chronic inflammatory disorders including periodontal disease.

Periodontal disease and hypertriglyceridemia in Japanese subjects: potential association with enhanced lipolysis

Although periodontal disease may be associated with increased risk for atherosclerosis, the mechanism by which the disease causes atherosclerosis is still unknown. The candidates contributing to atherosclerosis in periodontal disease include low-grade inflammation such as C-reactive protein (CRP) and insulin resistance. A previous study demonstrated that periodontal therapy leads to an improvement in CRP as well as insulin resistance, indicating the relationship between periodontal disease and low-grade inflammation or insulin resistance. On the other hand, we previously demonstrated that serum triglyceride (TG) per se is independently associated with CRP or insulin resistance in Japanese populations with a body mass index (BMI) of 21.5 to 27.0 (midrange BMI). To the best of our knowledge, however, the relationship between periodontal disease and serum TG is not fully clarified. The first aim of the present study is to investigate whether periodontal disease is associated with serum TG in Japanese subjects with midrange BMI. If so, another aim of the study is to determine which mechanism is responsible for the association between periodontal disease and serum TG in these subjects. We have performed a periodontal examination in the Ogaki metabolic syndrome medical examination. One hundred sixty-two participants from 40 to 74 years old (56 men and 106 women; mean age, 66.43 ± 6.25 years) were enrolled in the study. Besides medical examination, oral panoramic radiograph was taken for all participants. Average bone score was also calculated. Periodontal bone destruction increased according to the age of the participants (r = 0.227, P < .004, Spearman correlation coefficient). Periodontal bone destruction was also associated with serum TG levels (r = 0.299, P = .000). This association was more evident in subjects with midrange BMI (r = 0.332, P < .001). In subjects with midrange BMI, TG was not correlated with BMI or waste circumstances. Furthermore, TG was not associated with age itself in the midrange BMI group. We then investigated the lipolytic activity of endotoxin in cocultures of adipocytes and macrophages. Low-dose lipopolysaccharide dose-dependently increased lipolytic activity in cocultures, and this activity was neutralized by anti-tumor necrosis factor α neutralizing antibodies. These results suggest that periodontal infection, especially bacterial endotoxinemia, is associated with enhanced lipolysis and subsequent up-regulation of circulating TG in Japanese with midrange BMI.

Adiponectin inhibits osteoclastogenesis and bone resorption via APPL1-mediated suppression of Akt1

Adiponectin is an adipokine playing an important role in regulating energy homeostasis and insulin sensitivity. However, the effect of adiponectin on bone metabolism shows contradictory results according to different research studies. In this study femurs were isolated from genetically double-labeled mBSP9.0Luc/β-ACT-EGFP transgenic mice and were transplanted into adiponectin knock-out mice or wild type mice to investigate the effect of temporary exposure to adiponectin deficiency on bone growth and metabolism. We found that the growth of bone explants in adiponectin knock-out mice was significantly retarded. Histological analysis, microcomputed tomography analysis, and tartrate-resistant acid phosphatase staining revealed reduced trabecular bone volume, decreased cortical bone, and increased osteoclast number in bone explants in adiponectin knock-out mice. We then found that adiponectin inhibits RANKL-induced osteoclastogenesis from RAW264.7 cells and down-regulates RANKL-enhanced expressions of osteoclastogenic regulators including NFAT2, TRAF6, cathepsin K, and tartrate-resistant acid phosphatase. Adiponectin also increases osteoclast apoptosis and decreases survival/proliferation of osteoclast precursor cells. Using siRNA specifically targeting APPL1, the first identified adaptor protein of adiponectin signaling, we found that the inhibitory effect of adiponectin on osteoclasts was induced by APPL1-mediated down-regulation of Akt1 activity. In addition, overexpression of Akt1 successfully reversed adiponectin-induced inhibition in RANKL-stimulated osteoclast differentiation. In conclusion, adiponectin is important in maintaining the balance of energy metabolism, inflammatory responses, and bone formation.