Does a causal relation between cardiovascular disease and periodontitis exist?

Oleogel-based drug delivery for the treatment of periodontitis: current strategies and future perspectives

Periodontitis is the chronic inflammation of tooth-supporting tissues that leads to loss of tooth support if untreated. Conventional therapy for periodontitis (mechanical removal of microbial biofilm and oral hygiene enforcement) is augmented by anti-microbial and anti-inflammatory drugs. These drugs are frequently delivered locally into the periodontal pocket for maximum efficiency and minimum adverse effects. The potential of oleogels for periodontal drug delivery has been discussed and further, the future scope of oleogel-based drug delivery systems in dentistry. An oleogel-based local drug delivery system offers several advantages over other systems. Superior mechanical properties (firmness and compressibility), muco-adhesion, shear thinning, thixotropy, controlled drug release and the ability to incorporate water-insoluble drugs clearly distinguish and highlight the potential of oleogels as periodontal local drug delivery systems. Bigels can combine the qualities of both hydrogels and oleogels to provide a more promising option for drug delivery. However, there is limited evidence concerning oleogels as local drug delivery agents in periodontics. Further studies are needed to discern the clinical efficacy of oleogel-based drug delivery systems.

Cardiovascular Diseases and Periodontitis

Periodontitis is a chronic inflammatory disease of the tooth-supporting connective tissue and alveolar bone that is initiated by a bacterial biofilm in periodontal pockets. It affects about half of adults in the Western world, and is associated with a range of systemic comorbidities, e.g., cardiovascular disease (CVD), diabetes and rheumatoid arthritis, and these diseases share overlapping systemic and target tissue inflammatory mechanisms. Indeed, mounting evidence has indicated that their association is causal and built on the presence of systemic low-grade inflammation (LGI). Prior research linking periodontitis to CVD has mainly been derived from experimental studies, observational data, and small interventional trials with surrogate markers of CVD, e.g., endothelial dysfunction. However, recent data from randomised studies have demonstrated that intensive treatment of periodontitis can reduce blood pressure in patients with hypertension in conjunction with reduction of systemic inflammatory markers. Furthermore, targeted anti-inflammatory therapy has been shown to reduce recurrent events in patients with established CVD and LGI. Along this line, the concept of residual inflammatory risk has emerged as an independent new risk factor for atherothrombotic CVD. The present review summarizes translational evidence indicating that periodontitis is a risk factor for CVD dependent on LGI, and we conclude that treatment of periodontitis is likely to contribute importantly to reduction of residual inflammatory risk.

Oral health and all-cause, cardiovascular disease, and respiratory mortality in older people in the UK and USA

Preventing deterioration of oral health in older age can be crucial for survival. We aimed to examine associations of oral health problems with all-cause, cardiovascular disease (CVD), and respiratory mortality in older people. We used cohort data from the British Regional Health Study (BRHS) (N = 2147, 71-92 years), and the Health, Aging and Body Composition (HABC) Study (USA) (N = 3075, 71-80 years). Follow-up was 9 years (BRHS) and 15 years (HABC Study). Oral health comprised tooth loss, periodontal disease, dry mouth, and self-rated oral health. Cox regression was performed for all-cause mortality, competing risks for CVD mortality, and accelerated failure time models for respiratory mortality. In the BRHS, tooth loss was associated with all-cause mortality (hazard ratio (HR) = 1.59, 95% CI 1.09, 2.31). In the HABC Study, tooth loss, dry mouth, and having ≥ 3 oral problems were associated with all-cause mortality; periodontal disease was associated with increased CVD mortality (subdistribution hazard ratio (SHR) = 1.49, 95% CI 1.01, 2.20); tooth loss, and accumulation of oral problems were associated with high respiratory mortality (tooth loss, time ratio (TR) = 0.73, 95% CI 0.54, 0.98). Findings suggest that poor oral health is associated with mortality. Results highlight the importance of improving oral health to lengthen survival in older age.

Associations between Pharmacotherapy for Cardiovascular Diseases and Periodontitis

The goal of the study was to assess the relationship between cardioprotective medications, i.e., beta-blockers, angiotensin-converting enzyme inhibitors (ACEIs), calcium channel blockers (CCBs), angiotensin II receptor blockers (ARBs), statins, acetylsalicylic acid (ASA), and periodontitis (PD).

BACKGROUND

Xerostomia increases the risk of PD and is a side effect of some pharmacotherapies. Information about the effect of cardioprotective treatment of periodontal status is scarce.

METHODS

We studied 562 dentate residents of Krakow at the age of 50 to 70 years. Information about treatment was collected using a standardized questionnaire. The pocket depth and clinical attachment level (CAL) were used to ascertain PD. Multivariate logistic regression was applied to assess the relation between cardioprotective medications and PD.

RESULTS

PD was found in 74% of participants. The range of cardioprotective drug use among participants was 7% (ARBs) to 32% (beta-blockers). After adjusting for age, sex, number of teeth, smoking, and education, ASA's use was related to a lower prevalence of PD in all dentate participants (odds ratio (OR) = 0.63, 95% confidence interval (CI): 0.40-0.99). The use of ARBs and statins was found to be associated with a higher prevalence of PD in persons having ≥6 teeth (odds ratio (OR) = 3.57, 95% CI: 1.06-11.99 and OR = 1.81, 95% CI: 1.03-3.16, respectively). Further adjustment for CVD risk factors, history of coronary heart disease, and other chronic diseases did not attenuate the results. There was no significant relation between PD and the use of other cardioprotective drugs.

Meloxicam-loaded solvent exchange-induced in situ forming beta-cyclodextrin gel and microparticle for periodontal pocket delivery

The in situ forming system has attracted attention for periodontitis treatment owing to its sustainable drug release localisation at a periodontal pocket. Given its low aqueous solubility, beta-cyclodextrin (β-CD) may serve as a matrix former of solvent exchange-induced in situ forming gel (ISG) and microparticle (ISM). Meloxicam (Mex)-loaded-β-CD ISG and ISM were prepared using β-CD in dimethyl sulphoxide (ISG) as the internal phase and camellia oil comprising 5% glyceryl monostearate as the external phase (ISM). Mex-loaded β-CD systems comprising 40% β-CD were easily injected via a 24-gauge needle. During solvent exchange with phosphate buffer saline (pH 6.8), the highly concentrated β-CD ISG promoted the phase inversion of β-CD aggregates into matrix-like. Upon exposure to aqueous phase, the ISM system comprising 40% β-CD transformed into microparticles and extended the drug release to 7 days with minimised initial burst release following Fickian diffusion. Moreover, the potential degradability was evident from the high weight loss. High maximum deformation force with high viscous character initiated the slow diffusion rate of the solvent from the ISM system. Therefore, 40% β-CD ISM is a potential local Mex-controlled release system of anti-inflammatory drug for periodontitis treatment.

Deletion of a conserved transcript PG_RS02100 expressed during logarithmic growth in Porphyromonas gingivalis results in hyperpigmentation and increased tolerance to oxidative stress

The oral obligate anaerobe Porphyromonas gingivalis possesses a small conserved transcript PG_RS02100 of unknown function we previously identified using small RNA-seq analysis as expressed during logarithmic growth. In this study, we sought to determine if PG_RS02100 plays a role in P. gingivalis growth or stress response. We show that a PG_RS02100 deletion mutant’s (W83Δ514) ability to grow under anaerobic conditions was no different than wildtype (W83), but it was better able to survive hydrogen peroxide exposure when cultured under heme limiting growth conditions, and was more aerotolerant when plated on enriched whole blood agar and exposed to atmospheric oxygen. Together, these results indicate that PG_RS02100 plays a role in surviving oxidative stress in actively growing P. gingivalis and that P. gingivalis’ response to exogenous hydrogen peroxide stress is linked to heme availability. Relative qRT-PCR expression analysis of oxyR, trx-1, tpx, sodB, ahpC, dinF, cydB, and frd, in W83Δ514 and W83 in response to 1 h exogenous dioxygen or hydrogen peroxide exposure, when cultured with varying heme availability, support our phenotypic evidence that W83Δ514 has a more highly primed defense system against exogenous peroxide, dioxygen, and heme generated ROS. Interestingly, W83Δ514 turned black faster than W83 when cultured on whole blood agar, suggesting it was able to accumulate heme more rapidly. The mechanism of increased heme acquisition observed in W83Δ514 is not yet known. However, it is clear that PG_RS02100 is involved in modulating the P. gingivalis cell surface in a manner related to survival, particularly against oxidative stress.

Development of hydrogels, oleogels, and bigels as local drug delivery systems for periodontitis

Periodontal disease is a chronic inflammation of gum and tissues that surround and support the teeth. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used in the treatment of periodontitis to ease swelling and inflammation. One approach of treating periodontitis is loading the NSAIDs in local drug delivery systems. Therefore, the objective of this study was to investigate the local delivery of the NSAIDs model drug ibuprofen to treat periodontitis using different types of gel formulations (hydrogel, oleogel, and bigel). Gel formulations were characterized in terms of their rheological properties (flow behavior, viscoelastic, and bioadhesive properties) using a controlled-stress rheometer. The in vitro drug release of ibuprofen from gel formulations was investigated using Franz diffusion cells. Gels exhibited more solid-like (elastic) behavior. The viscosity and viscoelastic properties were in the order of oleogel > bigel > hydrogel, respectively. In bioadhesion study, mucin dispersion/plain ibuprofen-hydrogel mixture showed a frequency-dependent interaction of ΔG' = -31 and ΔG' = + 53 Pa at 1 and 10 rad/s, respectively. A strong positive interaction (ΔG' = + 6000 and +130,667 Pa at 1 and 10 rad/s, respectively) was found in mucin dispersion/plain ibuprofen-oleogel mixture. The extent of the negative interaction increased in mucin dispersion/plain ibuprofen-bigel mixture (ΔG' = -59,000 and -79,375 Pa at 1 and 10 rad/s, respectively). After 6 h, ibuprofen release from hydrogel, oleogel, and bigel was 59.5 ± 2.2, 80.6 ± 3.9, and 94.6 ± 3.2%, respectively. Results showed that the rheological and bioadhesive properties and in vitro drug release were influenced by the type of gel formulations.

Periodontitis in patients with cirrhosis: a cross-sectional study

BACKGROUND

Many patients with cirrhosis have poor oral health but little is known on periodontitis, and its clinical significance is largely unknown. This study aimed to examine the prevalence and predictors of periodontitis, and evaluate the association of periodontitis with nutritional and systemic inflammation status.

METHODS

145 patients with cirrhosis were consecutively enrolled. Clinical, oral examination of plaque, pocket depth, clinical attachment level, and bleeding on probing was performed. Patients were categorized as having no-or-mild, moderate, or severe periodontitis. Predictors of severe periodontitis and the association with nutritional and systemic inflammation status were analyzed using univariable and multivariable logistic regression analyses.

RESULTS

The large majority of patients had periodontitis, 46% of them severely and 39% moderately. Predictors of severe periodontitis included smoking (odds ratio (OR) 2.93, 95% confidence interval (CI) 1.29-6.63), brushing teeth twice daily (OR 0.30, 95% CI 0.11-0.79), and visiting the dentist annually (OR 3.51, 95% CI 1.22-10.81). Cirrhosis etiology or severity was not predictors of severe periodontitis. The patients with severe periodontitis had a higher nutritional risk score than patients with moderate, mild, or no periodontitis (3, interquartile range (IQR) 3-5 vs. 3, IQR 2-4, P = 0.02).

CONCLUSIONS

Most cirrhosis patients had significant periodontitis, the severity of which was related to life style factors and was associated with higher nutrition risk score. Our results emphasize the need for further research to establish the effect of periodontitis on cirrhosis.

Immunoglobulin G antibodies against Porphyromonas gingivalis or Aggregatibacter actinomycetemcomitans in cardiovascular disease and periodontitis

Objectives: The aim was to elucidate whether levels of circulating antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis correlate to loss of attachment, as a marker for periodontitis and cardiovascular disease (CVD). Design: Sera were collected from 576 participants of the Danish Health Examination Survey (DANHES). Immunoglobulin G antibodies against lipopolysaccharide (LPS) and protein antigens from the a, b and c serotypes of A. actinomycetemcomitans and P. gingivalis were quantified by titration in ELISA plates coated with a mixture of antigens prepared by disintegration of bacteria. Results: Levels of antibodies against P. gingivalis (OR = 1.48) and A. actinomycetemcomitans (1.31) associated with periodontitis, as determined by univariable logistic regression analysis. These antibody levels also associated with CVD (1.17 and 1.37), respectively, However, after adjusting for other risk factors, including age, smoking, gender, alcohol consumption, overweight, and level of education using multivariable logistic regression analysis, only increasing body mass index (BMI; 1.09), previous smoking (1.99), and increasing age (decades) (2.27) remained associated with CVD. Increased levels of antibodies against P. gingivalis (1.34) remained associated with periodontitis after adjusting for other risk factors. Conclusions: CVD and periodontitis were associated with levels of IgG antibodies to P. gingivalis or A. actinomycetemcomitans in univariable analyses, but only the association of P. gingivalis antibody levels with periodontitis reached statistical significance after adjustment for common confounders. Age, in particular, influenced this relationship.

Porphyromonas gingivalis-induced production of reactive oxygen species, tumor necrosis factor-α, interleukin-6, CXCL8 and CCL2 by neutrophils from localized aggressive periodontitis and healthy donors: modulating actions of red blood cells and resolvin E1

BACKGROUND AND OBJECTIVES

Porphyromonas gingivalis is regarded as a significant contributor in the pathogenesis of periodontitis and certain systemic diseases, including atherosclerosis. P. gingivalis occasionally translocates from periodontal pockets into the circulation, where it adheres to red blood cells (RBCs). This may protect the bacterium from contact with circulating phagocytes without affecting its viability.

MATERIAL AND METHODS

In this in vitro study, we investigated whether human peripheral blood neutrophils from 10 subjects with localized aggressive periodontitis (LAgP) and 10 healthy controls release the proinflammatory cytokines interleukin (IL)-6, tumor necrosis factor α (TNF-α), the chemokine (C-X-C motif) ligand 8 (CXCL8; also known as IL-8) and chemokine (C-C motif) ligand 2 (CCL2; also known as monocyte chemotactic protein-1) and intracellular reactive oxygen species (ROS) in response to challenge with P. gingivalis. In addition, the impact of RBC interaction with P. gingivalis was investigated. The actions of resolvin E1 (RvE1), a known regulator of P. gingivalis induced neutrophil responses, on the cytokine and ROS responses elicited by P. gingivalis in cultures of neutrophils were investigated.

RESULTS

Upon stimulation with P. gingivalis, neutrophils from subjects with LAgP and healthy controls released similar quantities of IL-6, TNF-α, CXCL8, CCL2 and intracellular ROS. The presence of RBCs amplified the release of IL-6, TNF-α and CCL2 statistically significant in both groups, but reduced the generation of ROS in the group of healthy controls, and showed a similar tendency in the group of subjects with LAgP. RvE1 had no impact on the production of intracellular ROS, TNF-α, IL-6, CXCL8 and CCL2 by neutrophils from either group, but tended to reduce the generation of ROS in subjects with LAgP in the absence of RBCs.

CONCLUSIONS

Our data support that binding to RBCs protects P. gingivalis from ROS and concomitantly enhances neutrophil release of proinflammatory cytokines providing a selective advantage for P. gingivalis growth.

Cholesterol crystals enhance TLR2- and TLR4-mediated pro-inflammatory cytokine responses of monocytes to the proatherogenic oral bacterium Porphyromonas gingivalis

Cholesterol deposits and pro-inflammatory cytokines play an essential role in the pathogenesis of atherosclerosis, a predominant cause of cardiovascular disease (CVD). Epidemiological evidence has linked periodontal disease (PD) with atherosclerotic CVD. Accordingly, viable periodontal pathogens, including Porphyromonas gingivalis, have been found in atherosclerotic plaques in humans and mice. We aimed to determine whether cholesterol crystals (CHCs) and oral bacteria synergize in the stimulation of human monocytes. Incubation of human monocytes with CHCs induced secretion of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-8. Moreover, CHCs markedly enhanced secretion of IL-1β by monocytes stimulated with the toll-like receptor (TLR) 4 agonist Escherichia coli lipopolysaccharide (LPS), and the TLR2 agonist Staphylococcus aureus lipoteichoic acid. Notably, CHCs also enhanced IL-1β secretion induced by P. gingivalis LPS and IL-1β secretion induced by whole P. gingivalis bacteria. This enhancement was abrogated by the NLRP3 inflammasome inhibitors Z-YVAD-FMK and glibenclamide. CHCs had no effect on cytokine production induced by P. gingivalis gingipains. Taken together, our findings support that CHCs, via stimulation of NLRP3 inflammasomes, act in synergy with the periodontal pathogen P. gingivalis to promote monocyte secretion of pro-atherogenic cytokines.

Periodontitis in older Swedish individuals fails to predict mortality

OBJECTIVES

This study aims to assess mortality risk and its association to health aspects in dentate individuals 60 years of age and older.

MATERIALS AND METHODS

Medical and periodontal data from 870 dentate individuals (age range 60–96) participating in the Swedish National Study on Aging and Care in Blekinge (SNACBlekinge)with survival statistics over 6 years were studied.

RESULTS

During 6 years of follow-up, 42/474 of the individuals(8.9 %), who at baseline were between age 60 and 75, and 134/396 individuals of the individuals (33.9 %), who at baseline were ≥75 years, died. Surviving dentate individuals had more teeth (mean 19.3, S.D.±7.9) than those who died (mean 15.9,S.D.±7.3; mean diff 3,3; S.E. mean diff 0.7; 95 % CI 2.0, 4.6;p=0.001). A self-reported history of high blood pressure (F=15.0, p<0.001), heart failure (F=24.5, p<0.001, observed power=0.99), older age (F=34.7, p<0.001), male gender(F=6.3, p<0.01), serum HbA1c with 6.5 % as cutoff level(F=9.3, p=0.002) were factors associated with mortality. A medical diagnosis of heart disease, diabetes, any form of cancer,or periodontitis failed to predict mortality.

CONCLUSIONS

A self-reported history of angina pectoris, chronic heart failure, elevated serum HbA1c, and few remaining teeth were associated with mortality risk. A professional diagnosis of cardiovascular disease, diabetes, cancer, or periodontitis was not predictive of mortality.

CLINICAL RELEVANCE

Self-health reports are important to observe in the assessment of disease and survival in older individual.

Presence and consequence of tooth periapical radiolucency in patients with cirrhosis

Background

Periapical radiolucency is the radiographic sign of inflammatory bone lesions around the apex of the tooth. We determined the prevalence and predictors of periapical radiolucency in patients with cirrhosis and the association with systemic inflammation status and cirrhosis-related complications.

Methods

A total of 110 cirrhosis patients were consecutively enrolled. Periapical radiolucency was defined as the presence of radiolucency or widening of the periapical periodontal ligament space to more than twice the normal width. Predictors of periapical radiolucency and the association with systemic inflammation markers and cirrhosis-related complications were explored by univariable and multivariable logistic regression analyses.

Results

Periapical radiolucency was present in one or more teeth in 46% of the patients. Strong predictors were gross caries (odds ratio [OR] 3.12, 95% confidence interval [CI] 1.43–6.79) and severe periodontitis (OR 3.98, 95% CI 1.04–15.20). Also old age (OR 1.10, 95% CI 1.01–1.19) and smoking (OR 3.24, 95% CI 1.02–17.62) were predictors. However, cirrhosis etiology (alcoholic vs nonalcoholic) or severity (Model of End-Stage Liver Disease score) were not predictors. The patients with periapical radiolucency had higher C-reactive protein (15.8 mg/L vs 8.1 mg/L, P=0.02) and lower albumin contents (25 g/L vs 28 g/L, P=0.04) than those without. Furthermore, the patients with periapical radiolucency had a higher prevalence of cirrhosis-related complications such as ascites, hepatic encephalopathy, and/or variceal bleeding (46% vs 27%, P=0.05).

Conclusion

Periapical radiolucency is often present as an element of poor oral health status and likely has an adverse clinical significance, which should motivate diagnostic and clinical attention to the findings.

Relation of Periodontitis to Risk of Cardiovascular and All-Cause Mortality (from a Danish Nationwide Cohort Study)

Periodontitis and atherosclerosis are highly prevalent chronic inflammatory diseases, and it has been suggested that periodontitis is an independent risk factor of cardiovascular disease (CVD) and that a causal link may exist between the 2 diseases. Using Danish national registers, we identified a nationwide cohort of 17,691 patients who received a hospital diagnosis of periodontitis within a 15-year period and matched them with 83,003 controls from the general population. We performed Poisson regression analysis to determine crude and adjusted incidence rate ratios of myocardial infarction, ischemic stroke, cardiovascular death, major adverse cardiovascular events, and all-cause mortality. The results showed that patients with periodontitis were at higher risk of all examined end points. The findings remained significant after adjustment for increased baseline co-morbidity in periodontitis patients compared with controls, for example, with adjusted incidence rate ratio 2.02 (95% CI 1.87 to 2.18) for cardiovascular death and 2.70 (95% CI 2.60 to 2.81) for all-cause mortality. Patients with a hospital diagnosis of periodontitis have a high burden of co-morbidity and an increased risk of CVD and all-cause mortality. In conclusion, our results support that periodontitis may be an independent risk factor for CVD.

Periodontitis in Chronic Heart Failure

Periodontal disease has been associated with an increased risk of cardiovascular events. The purpose of our study was to investigate whether a correlation between periodontitis and chronic heart failure exists, as well as the nature of the underlying cause. We enrolled 71 patients (mean age, 54 ± 13 yr; 56 men) who had stable chronic heart failure; all underwent complete cardiologic and dental evaluations. The periodontal screening index was used to quantify the degree of periodontal disease. We compared the findings to those in the general population with use of data from the 4th German Dental Health Survey. Gingivitis, moderate periodontitis, and severe periodontitis were present in 17 (24%), 17 (24%), and 37 (52%) patients, respectively. Severe periodontitis was more prevalent among chronic heart failure patients than in the general population. In contrast, moderate periodontitis was more prevalent in the general population (P <0.00001). The severity of periodontal disease was not associated with the cause of chronic heart failure or the severity of heart failure symptoms. Six-minute walking distance was the only independent predictor of severe periodontitis. Periodontal disease is highly prevalent in chronic heart failure patients regardless of the cause of heart failure. Prospective trials are warranted to clarify the causal relationship between both diseases.

Cross-talk between clinical and host-response parameters of periodontitis in smokers

BACKGROUND AND OBJECTIVE

Periodontal diseases are a major public health concern leading to tooth loss and have also been shown to be associated with several chronic systemic diseases. Smoking is a major risk factor for the development of numerous systemic diseases, as well as periodontitis. While it is clear that smokers have a significantly enhanced risk for developing periodontitis leading to tooth loss, the population varies regarding susceptibility to disease associated with smoking. This investigation focused on identifying differences in four broad sets of variables, consisting of: (i) host-response molecules; (ii) periodontal clinical parameters; (iii) antibody responses to periodontal pathogens and oral commensal bacteria; and (iv) other variables of interest, in a population of smokers with (n = 171) and without (n = 117) periodontitis.

MATERIAL AND METHODS

Bayesian network structured learning (BNSL) techniques were used to investigate potential associations and cross-talk between the four broad sets of variables.

RESULTS

BNSL revealed two broad communities with markedly different topology between the populations of smokers, with and without periodontitis. Confidence of the edges in the resulting network also showed marked variations within and between the periodontitis and nonperiodontitis groups.

CONCLUSION

The results presented validated known associations and discovered new ones with minimal precedence that may warrant further investigation and novel hypothesis generation. Cross-talk between the clinical variables and antibody profiles of bacteria were especially pronounced in the case of periodontitis and were mediated by the antibody response profile to Porphyromonas gingivalis.

Alveolar bone loss in osteoporosis: a loaded and cellular affair?

Maxillary and mandibular bone mirror skeletal bone conditions. Bone remodeling happens at endosteal surfaces where the osteoclasts and osteoblasts are situated. More surfaces means more cells and remodeling. The bone turnover rate in the mandibular alveolar process is probably the fastest in the body; thus, the first signs of osteoporosis may be revealed here. Hormones, osteoporosis, and aging influence the alveolar process and the skeletal bones similarly, but differences in loading between loaded, half-loaded, and unloaded bones are important to consider. Bone mass is redistributed from one location to another where strength is needed. A sparse trabeculation in the mandibular premolar region (large intertrabecular spaces and thin trabeculae) is a reliable sign of osteopenia and a high skeletal fracture risk. Having dense trabeculation (small intertrabecular spaces and well-mineralized trabeculae) is generally advantageous to the individual because of the low fracture risk, but may imply some problems for the clinician.

The role of Toll-like receptors in periodontitis

Periodontitis is a common infectious disease. Recent studies have indicated that the progression of periodontitis may be regulated by interactions between host immunity and periodontopathic bacteria. Although periodontopathic bacteria can destroy periodontal tissue, a dysfunctional host immune response triggered by the bacteria can lead to more severe and persistent destruction. Toll-like receptors (TLRs), a type of pattern recognition receptor (PRR) that recognizes pathogens, have been implicated in host innate immune responses to periodontopathic bacteria and in the activation of adaptive immunity. TLR-targeted drugs may hold promise to treat periodontal disease. This review summarizes recent studies on the role of TLRs in periodontitis and discusses areas needing further research. We believe TLRs may be an effective biomarker for the prevention, diagnosis, and treatment of periodontitis in the near future.

Absence of Bacteria on Coronary Angioplasty Balloons from Unselected Patients: Results with Use of a High Sensitivity Polymerase Chain Reaction Assay

Periodontitis is a chronic, bacterially-induced inflammatory disease of the tooth-supporting tissues, which may result in transient bacteremia and a systemic inflammatory response. Periodontitis is associated with coronary artery disease independently of established cardiovascular risk factors, and translocation of bacteria from the oral cavity to the coronary arteries may play a role in the development of coronary artery disease. Very few studies have used angioplasty balloons for in vivo sampling from diseased coronary arteries, and with varying results. Therefore, the aim of this study was to assess if bacterial DNA from primarily oral bacteria could be detected on coronary angioplasty balloons by use of an optimized sampling process combined with an internally validated sensitive polymerase chain reaction (PCR) assay. Coronary angioplasty balloons and control samples from a total of 45 unselected patients with stable angina, unstable angina/non-ST elevation myocardial infarction, and ST-elevation myocardial infarction (n = 15 in each group) were collected and analyzed using a PCR assay with high sensitivity and specificity for 16S rRNA genes of the oral microbiome. Despite elimination of extraction and purification steps, and demonstration of sensitivity levels of 25–125 colony forming units (CFU), we did not detect bacterial DNA from any of the coronary angioplasty balloons. A subsequent questionnaire indicated that the prevalence of periodontitis in the study cohort was at least 39.5%. Although coronary angioplasty balloons are unlikely to be useful for detection of bacteria with current PCR techniques in unselected patients with coronary artery disease, more studies are warranted to determine the extent to which bacteria contribute to atherosclerosis and its clinical manifestations and whether the presence of bacteria in the arteries is a transient phenomenon.

Antibiotic therapy in fully impacted lower third molar surgery: randomized three-arm, double-blind, controlled trial

PURPOSE

The aim of this study was to evaluate the efficacy of three drug protocols in patients undergoing extraction of fully impacted lower third molars.

METHODS

Eighty surgeries were performed on healthy patients using three randomized double-blind drug protocols: group 1 (G1), amoxicillin (1 g) 1 h before surgery + 500 mg 8/8 h for 7 days; group 2 (G2), 1-g amoxicillin 1 h before surgery plus placebo, with identical appearance to G1, 8/8 h for 7 days; and group 3 (G3), placebo 1 h before surgery and 500 mg 8/8 h for 7 days. The primary outcome criterion was mouth opening, and the secondary outcome criteria were facial edema and pain. Signals as body temperature, lymphadenopathy, and dysphagia characterize the sample. Evaluation was performed at baseline and on the 4th and 7th postoperative days by the same researcher.

RESULTS

There was no difference among groups with respect to any of the parameters evaluated (p > 0.05).

CONCLUSION

Under these experimental conditions, there is no advantage in the administration of antibiotics in healthy patients undergoing extraction of fully impacted lower third molars with a controlled aseptic chain.

Dietary exposure to benzoxazinoids enhances bacteria-induced monokine responses by peripheral blood mononuclear cells

SCOPE

To examine potentially immunomodulating effects of dietary benzoxazinoids (BXs), present in cereal grains.

METHODS AND RESULTS

Nineteen healthy volunteers were randomly distributed into two groups, who received diets with high or low content of BXs for 3 wk. After a week's wash-out, the groups switched diets. Peripheral blood mononuclear cells (PBMCs) were stimulated with Porphyromonas gingivalis, Escherichia coli lipopolysaccharide (LPS), or tetanus toxoid (TT). PBMCs from a healthy donor received the same stimuli in presence of serum from each participant receiving BXs. The production of monokines, T-cell cytokines and T-helper cell proliferation were assessed. A 3-wk diet with high BX content enhanced IL-1β responses against LPS and P. gingivalis, as well as TNF-α response against P. gingivalis, after 24 h of stimulation. Moreover, IL-6 was found to be increased after 7 days of stimulation with LPS. No effect was observed on T-cell cytokines or proliferation. BX levels in serum after a single meal did not modify cytokine responses.

CONCLUSION

High dietary intake of BXs enhances bacteria-induced production of pro-inflammatory monokines by PBMCs, but not T-cell responses; presumably due to intrinsic changes within PBMCs, built up over 3 wk of BX-rich diet, rather than to an immediate effects of BXs contained in serum.

The complement system and its role in the pathogenesis of periodontitis: current concepts

Periodontitis is a highly prevalent inflammatory disease in tooth supporting tissues, induced by bacteria growing in a biofilm on tooth surfaces. Components of the complement system are present in the periodontal tissue and the system is activated in periodontitis. Continuous complement activation and modulation by bacteria within the biofilm in periodontal pockets, however, may enhance local tissue destruction, providing the biofilm with both essential nutrients and space to grow. A more profound understanding of the mechanisms involved in complement-derived tissue degradation may facilitate the development of new treatment concepts for periodontitis. Further studies on the role of complement in periodontitis pathogenesis may also contribute to the understanding of why some individuals fail to resolve periodontitis. Here, we review evidence that links complement to the pathogenesis of periodontitis with an emphasis on interaction of complement with bacteria from periodontitis-associated biofilm.

Streptococcus sanguinis-induced cytokine and matrix metalloproteinase-1 release from platelets

Background

Streptococcus sanguinis (S.sanguinis), a predominant bacterium in the human oral cavity, has been widely associated with the development of infective endocarditis. Platelets play both a haemostatic function and can influence both innate and adaptive immune responses. Previous studies have shown that S.sanguinis can interact with, and activate, platelets.

Results

The aim of this study was to determine whether S.sanguinis stimulates the release of matrix metalloproteinases (MMPs) 1, 2 and 9 and the pro-inflammatory mediators SDF-1, VEGF and sCD40L, from platelets and to subsequently pharmacologically address the release mechanism (s). S.sanguinis stimulated the release of MMP-1, SDF-1, VEGF and sCD40L from platelets and inhibitors of cyclooxygenase and phosphatidylinositol 3-kinase, and antagonists of the αIIbβ3 integrin and glycoprotein Ib, each inhibited the secretion of all factors.

Conclusions

Therefore the release of MMP-1, SDF-1, VEGF and sCD40L occurs late in the platelet response to S.sanguinis and highlights the complex intracellular signalling pathways stimulated in response to S.sanguinis which lead to haemostasis, MMP and pro-inflammatory mediator secretion.

Porphyromonas Gingivalis and E-coli induce different cytokine production patterns in pregnant women

Objective

Pregnant individuals of many species, including humans, are more sensitive to various bacteria or their products as compared with non-pregnant individuals. Pregnant individuals also respond differently to different bacteria or their products. Therefore, in the present study, we evaluated whether the increased sensitivity of pregnant women to bacterial products and their heterogeneous response to different bacteria was associated with differences in whole blood cytokine production upon stimulation with bacteria or their products.

Methods

Blood samples were taken from healthy pregnant and age-matched non-pregnant women and ex vivo stimulated with bacteria or LPS from Porphyromonas Gingivalis (Pg) or E-coli for 24 hrs. TNFα, IL-1ß, IL-6, IL-12 and IL-10 were measured using a multiplex Luminex system.

Results

We observed a generally lower cytokine production after stimulation with Pg bacteria or it’s LPS as compared with E-coli bacteria. However, there was also an effect of pregnancy upon cytokine production: in pregnant women the production of IL-6 upon Pg stimulation was decreased as compared with non-pregnant women. After stimulation with E-coli, the production of IL-12 and TNFα was decreased in pregnant women as compared with non-pregnant women.

Conclusion

Our results showed that cytokine production upon bacterial stimulation of whole blood differed between pregnant and non-pregnant women, showing that the increased sensitivity of pregnant women may be due to differences in cytokine production. Moreover, pregnancy also affected whole blood cytokine production upon Pg or E-coli stimulation differently. Thus, the different responses of pregnant women to different bacteria or their products may result from variations in cytokine production.

Smoking-related cotinine levels and host responses in chronic periodontitis

BACKGROUND AND OBJECTIVE

Smoking has been reported to increase the risk of periodontal disease by disrupting the balance of immune responses and tissue repair processes; however, this risk varies among smokers. Cotinine levels in saliva are routinely used to measure the level of smoking, and reflect the quantity of nicotine, and other smoking-related xenobiotics that challenge host systems. This study delineated characteristics of inflammatory mediators in saliva and serum antibody responses to both periodontal pathogens and commensal bacteria in smokers as they related to cotinine levels.

MATERIALS AND METHODS

This case-control study (n = 279) examined salivary inflammatory mediator responses [interleukin (IL)-1ß, IL-10, prostaglandin E2, myeloperoxidase and plasminogen activator inhibitor-1], and serum IgG antibody responses to three periodontal pathogens (Aggregatibacter actinomyce-temcomitans, Porphyromonas gingivalis, Treponema denticola) and five commensal oral microorganisms (Veillonella parvula, Streptococcus sanguis, Prevotella loescheii, Actinomyces naeslundii, Capnocytophaga ochracea).

RESULTS

The patients were stratified into health (n = 30), gingivitis (n = 55) and periodontitis (n = 184); cotinine levels correlated with reported smoking habits in health, less so with gingivitis, and were not correlated in periodontitis. Of the inflammatory mediators/acute phase proteins, only IL-1ß levels were positively associated (p < 0.001) with the pack years and cotinine levels. As might be predicted, patients with periodontitis smoked more (p < 0.001) and had higher levels of cotinine. IL-1ß and antibody to A. actinomycetemcomitans, P. gingivalis and T. denticola were significantly higher in the patients with periodontitis than either patients with gingivitis or who were healthy.

CONCLUSIONS

Generally, antibody to the pathogens and commensals was lower with decreased cotinine levels. Smoking exacerbated differences in both inflammatory mediators and three antibody in periodontal disease compared to healthy subjects.

Expression of Porphyromonas gingivalis small RNA in response to hemin availability identified using microarray and RNA-seq analysis

There is a significant body of work suggesting that sRNA-mediated post-transcriptional regulation is a conserved mechanism among pathogenic bacteria to modulate bacterial virulence and survival. Porphyromonas gingivalis is recognized as an etiological agent of periodontitis and implicated in contributing to the development of multiple inflammatory diseases including cardiovascular disease. Using NimbleGen microarray analysis and a strand-specific method to sequence cDNA libraries of small RNA-enriched P. gingivalis transcripts using Illumina's high-throughput sequencing technology, we identified putative sRNA and generated sRNA expression profiles in response to growth phase, hemin availability after hemin starvation, or both. We identified transcripts that mapped to intergenic sequences as well as antisense transcripts that mapped to open reading frames of the annotated genome. Overall, this approach provided a comprehensive way to survey transcriptional activity to discover functionally linked RNA transcripts, responding to specific environmental cues, that merit further investigation.

Porphyromonas gingivalis modulates Pseudomonas aeruginosa-induced apoptosis of respiratory epithelial cells through the STAT3 signaling pathway

Pseudomonas aeruginosa is an important opportunistic bacterial pathogen, causing infections of respiratory and other organ systems in immunocompromised hosts that may invade and proliferate in mucosal epithelial cells to induce apoptosis. Previous studies suggest that oral bacteria, especially gram-negative periodontal pathogens, may enhance P. aeruginosa invasion into respiratory epithelial cells to augment tissue destruction. In this study, we investigated the effect of the periodontopathogen Porphyromonas gingivalis on P. aeruginosa-induced epithelial cell apoptosis. P. gingivalis invasion transiently inhibited P. aeruginosa-induced apoptosis in respiratory epithelial cells via the signal transducer and activator of transcription 3 (STAT3) signaling pathway. The activated STAT3 up-regulated the downstream anti-apoptotic moleculars survivin and B-cell leukemia-2 (bcl-2). This process was accompanied by down-regulation of pro-apoptosis molecular Bcl-2-associated death promoter (bad) and caspase-3 activity inhibition. In addition, the activation of the STAT3 pathway was affected by P. gingivalis in a dose-dependent manner. Finally, co-invasion of P. aeruginosa and P. gingivalis led to greater cell death compared with P. aeruginosa challenge alone. These results suggest that regulation of P. aeruginosa-induced apoptosis by P. gingivalis contributes to the pathogenesis of respiratory disease. Interference with this process may provide a potential therapeutic strategy for the treatment and prevention of respiratory disease.