The pathobiology of periodontal diseases may affect systemic diseases: inversion of a paradigm

Evaluation of the Incidence of Periodontitis-Associated Bacteria in the Atherosclerotic Plaque of Coronary Blood Vessels

BACKGROUND

Unstable atherosclerotic plaque is a dangerous clinical condition, possibly leading to acute coronary deficiency resulting in cardiac infarction. Questions about the role of inflammatory factors in the formation of pathological lesions in the endothelium of coronary vessels have often been raised. This condition may be caused by bacteria that are able to initiate clot formation in a blood vessel, destabilizing an atherosclerotic plaque that is already present. The sources of these pathogens are chronic inflammatory processes occurring in the host, including periodontal disease, which is one of the most frequent conditions. The aim of this study was to evaluate the incidence of selected anaerobic bacteria in subgingival and atherosclerotic plaque in patients treated surgically because of coronary vessel obliteration.

METHODS

The study was performed on 20 individuals with chronic periodontitis. Subgingival plaque was collected from periodontal pockets >5 mm. DNA testing was used to identify eight pathogens responsible for periodontal tissue destruction. Material from atherosclerotic plaques was collected from the same patients during bypass surgery, and DNA testing by the same method was performed.

RESULTS

In 13 of 20 patients, the pathogens most frequently found in severe chronic periodontitis were also found in coronary vessels. In 10 cases, those species of bacteria were also present in atherosclerotic plaque. The most frequently identified bacteria were Porphyromonas gingivalis and Treponema denticola.

CONCLUSIONS

In patients with the severe form of chronic periodontitis, it seems that clinical attachment loss is not associated with bacterial permeability into coronary vessels. What is important is the presence of an active inflammatory process expressed by a significantly higher bleeding index in those patients in whom the examined bacterial species were found in atherosclerotic plaque.

Elevated serum interleukin-6 (IL-6) in solid-organ transplant recipients is positively associated with tissue destruction and IL-6 gene expression in the periodontium

BACKGROUND

The number of transplanted solid organs and life expectancy after transplantation are steadily rising worldwide. Inflammation is widely recognized as playing a pivotal role in transplant rejection, and several studies have shown that serum interleukin-6 (IL-6) levels can identify individuals who are at greater risk for rejection. Given the known association between IL-6 and chronic periodontitis, the aim of our study was to assess the periodontal status of solid-organ transplant subjects compared to systemically healthy controls, to quantify the IL-6 levels in the serum and periodontal tissues, and to explore their association.

METHODS

Forty-seven heart and kidney transplant and 18 systemically healthy age-matched individuals were recruited. Subjects received a complete periodontal examination, and blood and periodontal tissue samples were collected for quantification of IL-6 protein and mRNA levels, respectively.

RESULTS

Transplant subjects had significantly higher serum IL-6 levels and slightly but statistically significantly increased mean probing depths than healthy controls. Multivariable linear regression analysis adjusting for gender, diabetes, smoking, and immunosuppressant dose showed that the mean probing depth, number of missing teeth, and mean percentage of sites with > or =4 mm attachment loss were independent predictors for elevated serum IL-6 levels. Transplant subjects with chronic periodontitis had higher mean serum IL-6 levels than those without chronic periodontitis, and there was a positive correlation between periodontal IL-6 gene expression levels and serum IL-6 protein levels.

CONCLUSIONS

Periodontal tissue destruction and local IL-6 synthesis are associated with elevated serum IL-6 levels in transplant recipients. This may have serious implications in solid-organ transplant deterioration and chronic rejection.

Effects of etanercept, a tumour necrosis factor-alpha antagonist, in an experimental model of periodontitis in rats

BACKGROUND AND PURPOSE

Etanercept is a tumour necrosis factor antagonist with anti-inflammatory effects. The aim of our study was to evaluate, for the first time, the therapeutic efficacy of in vivo inhibition of TNF-alpha in an experimental model of periodontitis.

EXPERIMENTAL APPROACH

Periodontitis was induced in adult male Sprague-Dawley rats by placing a nylon thread ligature around the lower 1st molars. Etanercept was administered at a dose of 5 mg kg-1, s.c., after placement of the ligature.

KEY RESULTS

Periodontitis in rats resulted in an inflammatory process characterized by oedema, neutrophil infiltration and cytokine production that was followed by the recruitment of other inflammatory cells, production of a range of inflammatory mediators, tissue damage, apoptosis and disease. Treatment of the rats with etanercept (5 mg kg-1, s.c., after placement of the ligature) significantly reduced the degree of (1) periodontitis inflammation and tissue injury (histological score), (2) infiltration of neutrophils (MPO evaluation), (3) iNOS (the expression of nitrotyrosine and cytokines (eg TNF-alpha)) and (4) apoptosis (Bax and Bcl-2 expression).

CONCLUSIONS AND IMPLICATIONS

Taken together, our results clearly demonstrate that treatment with etanercept reduces the development of inflammation and tissue injury, events associated with periodontitis.

Polymerase chain reaction-based denaturing gradient gel electrophoresis in the evaluation of oral microbiota

BACKGROUND/AIMS

Clinical evaluation of oral microbial reduction after a standard prophylactic treatment has traditionally been based on bacterial cultivation methods. However, not all microbes in saliva or dental plaque can be cultivated. Polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE) is a cultivation-independent molecular fingerprinting technique that allows the assessment of the predominant bacterial species present in the oral cavity. This study sought to evaluate the oral microbial changes that occurred after a standard prophylactic treatment with a conventional oral care product using PCR-DGGE.

METHODS

Twelve healthy adults participated in the study. Pooled plaque samples were collected at baseline, 24 h after prophylaxis (T1), and 4 days after toothbrushing with fluoride toothpaste (T4). The total microbial genomic DNA of the plaque was isolated. PCR was performed with a set of universal bacterial 16S rDNA primers. The PCR-amplified 16S rDNA fragments were separated by DGGE. The effects of the treatment and of dental brushing were assessed by comparing the PCR-DGGE fingerprinting profiles.

RESULTS

The mean numbers of detected PCR amplicons were 22.3 +/- 6.1 for the baseline group, 13.0 +/- 3.1 for the T1 group, and 13.5 +/- 4.3 for the T4 group; the differences among the three groups were statistically significant (P < 0.01). The study also found a significant difference in the mean similarities of microbial profiles between the baseline and the treatment groups (P < 0.001).

CONCLUSION

PCR-based DGGE has been shown to be an excellent means of rapidly and accurately assessing oral microbial changes in this clinical study.

Periodontitis Is an Important and Occult Source of Inflammation in Hemodialysis Patients

AIM

To evaluate the association between C-reactive protein (CRP) levels and the periodontal status of hemodialysis (HD) patients.

METHODS

41 HD patients on rHuEPO therapy were enrolled in the study. Hematologic and biochemical parameters and CRP levels were recorded. The plaque index, gingival index, probing pocket depth and periodontal disease index were used to identify periodontal disease. The patients were divided into 2 groups: group 1 (n = 21), high CRP, and group 2 (n = 20), normal CRP.

RESULTS

After periodontal therapy, while the mean CRP level and erythrocyte sedimentation rate declined from 30.46 to 10.36 (p = 0.001) and from 93.4 to 35.8 mg/l (p = 0.001), respectively, the hemoglobin level increased from 9.4 to 10.6 g/dl (p = 0.009) and hematocrit level from 28.2 to 32.0% (p = 0.008) in group 1.

CONCLUSION

Periodontitis is an important and occult source of chronic inflammation and increases the CRP levels in HD patients. Periodontitis can cause hyporesponsiveness to rHuEPO treatment and decrease the hemoglobin levels.

Relationship of serum advanced glycation end products with deterioration of periodontitis in type 2 diabetes patients

BACKGROUND

A close relationship between diabetes and chronic periodontitis has been demonstrated. We previously found that Porphyromonas gingivalis with the type II fimA gene is an infectious factor closely associated with the deterioration seen in diabetic periodontitis patients. In the present study, we examined whether other biomarkers are related to the development and deterioration of periodontitis often seen in type 2 diabetic individuals.

METHODS

A total of 97 type 2 diabetes patients with and without periodontitis were recruited, and their periodontal and diabetic conditions were analyzed. The ratio (%) of teeth with an attachment loss >5 mm among all teeth in each subject was used as an index of periodontal deterioration. Peripheral blood was tested for levels of glycated hemoglobin (HbA1c), advanced glycation end products (AGEs), C-reactive protein (CRP), and cytokines (tumor necrosis factor [TNF]-alpha and interleukin [IL]-1beta). Subgingival plaque samples were also examined for the occurrences of Actinobacillus actinomycetemcomitans, Tannerella forsythensis, Treponema denticola, and Prevotella intermedia.

RESULTS

Serum AGEs were significantly associated with deterioration of periodontitis, whereas no other serum biochemical marker or bacterial occurrence showed a clear relationship with that condition.

CONCLUSION

AGEs may be factors associated with diabetic periodontitis and may be useful as biomarkers that reflect such deterioration.

Fibrinogen-neutrophil interactions in response to fMLP and Porphyromonas gingivalis fimbrial peptides

Porphyromonas gingivalis (P.g) is the primary bacterial agent in many forms of chronic periodontitis. Since polymorphonuclear leukocytes (PMNs) are first-line responders to P.g.- induced inflammation, and fibrinogen is important for in vivo PMN in this disease, we have studied the effect of N-formyl-methionyl-leucyl-phenylalanine (fMLP) (an inflammatory stimulus), P.g. fimbriae and fimbrial peptides (based on FimA, the main structural protein of P.g. fimbriae) on PMN-fibrinogen interactions. Freshly isolated human PMNs were allowed to react with FITC-Fibrinogen and various fimbrial peptides (denoted as FimA followed by amino acid number within whole FimA protein), and FITC-Fibrinogen binding was measured using flow cytometry. Freshly isolated neutrophils were also challenged with Fibrinogen and/or fimbrial peptides to measure IL-8 secretion using ELISA. Our studies show that fibrinogen binding to PMNs is enhanced (p < 0.01) in response to fMLP as well as fimbrial peptides (FimA 61-80) containing the motif LTTE (p < 0.01) in a dose dependent manner but not in response to peptides without that motif. We also observed that fMLP and FimA 61-80 have an additive effect on fibrinogen binding to PMNs (p < 0.05), and fMLP and FimA 171-185 significantly inhibit fMLP-induced fibrinogen binding (p < 0.01). To determine of the role of inflammatory cytokines, we examined IL-8 release from PMNs in response to combinations of P. gingivalis fimbriae, fMLP and fibrinogen. In all cases, IL-8 release increased in a dose-dependent manner (p < 0.05). fMLP-fibrinogen effect on IL-8 release from PMNs was synergistic while fimbriae-fibrinogen effect was additive. In summary, PMN priming by fimbrial peptides facilitates fibrinogen-PMN interaction and may increase inflammation.

Periodontitis and pregnancy

There is an increasing amount of evidence suggesting a systemic link between periodontal disease in the pregnant mother and pre-term low birth weight (PLBW). Severe periodontitis affects at least 10% of the general population. The aetiology of periodontitis is essentially a bacterially induced inflammatory reaction within the attachment surrounding the teeth. Maternal infection has been linked with pre-term delivery. Normal pregnancy itself is associated with inflammatory changes very similar to those found in sepsis. Because the infected periodontal tissues can act as a reservoir for both bacterial products and inflammatory cytokines, it may be possible that periodontal infection and the resultant inflammation could be linked with PLBW. Current understanding suggests that prostaglandins and proinflammatory cytokines play a pivotal role in the initiation process because of the close relationship of inflammation and infection. High levels of maternally or fetally derived cytokines such as tumour necrosis factor alpha (TNFalpha) may enhance amniochorionic and decidual interleukin six (IL-6) expression. Prostaglandin E2 (PGE2) has also been associated with periodontitis and PLBW. Periodontitis is a possible risk factor for PLBW with an odds ratio of 2.30. For the majority of individuals affected with periodontitis, the condition is symptom-free until the disease is more advanced. Therefore there is the need for medical carers of pregnant patients to increase the awareness among pregnant women themselves. Although there is plenty of evidence associating periodontitis with PLBW, interventional studies for the treatment of periodontitis measuring the impact on PLBW are few in number. Therefore more good quality clinical trials are required to address this issue.

Effect of Vitamin D and Calcium on Periodontitis

The anthropological record indicates that we are exposed to considerably less ultraviolet radiation (required for the synthesis of vitamin D) and consume considerably less calcium than did our early ancestors. Most U.S. citizens have calcium intakes and serum levels of vitamin D far below recommended values. This is despite there having been extensive evidence that optimal calcium and vitamin D intakes not only benefit our postcranial bone health but also have many other health benefits. Numerous articles indicate that vitamin D and calcium deficiencies result in bone loss and increased inflammation, which are well recognized symptoms of periodontal disease. For more than 40 years, investigators have suggested that calcium intake may be associated with alveolar bone resorption, and more recently there have been a number of studies in which investigators have suggested that calcium and vitamin D may benefit periodontal health, and it has been suggested that calcium deficiency may be a risk factor for periodontal disease. There has not, however, been a vitamin-D-calcium-periodontitis clinical trial in which randomization and masking were carefully controlled, the periodontal disease status of patients known, periodontal disease measures were the primary outcomes, and levels of intake optimized to produce maximal effects. Such research might demonstrate that calcium and vitamin D are important adjuncts to standard treatments for preventing and treating periodontal disease.

Molecular and imaging techniques for bacterial biofilms in joint arthroplasty infections

Biofilm formation on surfaces is an ancient and integral strategy for bacterial survival. Billions of years of adaptation provide microbes with the ability to colonize any surface, including those used in orthopaedic surgery. Although remarkable progress has been made in the treatment of orthopaedic diseases with implanted prostheses, infection rates remain between 1% and 2%, and are higher for revision surgeries. The chronic nature of implant infections, their nonresponsiveness to antibiotics, and their frequent culture negativity can be explained by the biofilm paradigm of infectious disease. However, the role of biofilms in orthopaedic implant infections and aseptic loosening is controversial. To address these issues, we developed molecular diagnostic and confocal imaging techniques to identify and characterize biofilms associated with infected implants. We designed PCR and reverse transcription (RT)-PCR-based assays that can be used to detect bacterial infections associated with culture-negative joint effusions that distinguish between physiologically active Staphylococcus aureus and Staphylococcus epidermidis. Using clinical isolates of Pseudomonas aeruginosa, we constructed a series of reporter strains expressing colored fluorescent proteins to observe biofilms growing on 316L stainless steel and titanium orthopaedic screws. Three-dimensional structures of Pseudomonas aeruginosa and staphylococci biofilms growing on the screws were documented using confocal microscopy. The application of these tools for clinical diagnosis and biofilm research in animal and in vitro models is discussed.

Effect of periodontal treatment on the C-reactive protein and proinflammatory cytokine levels in Japanese periodontitis patients

BACKGROUND

Recent epidemiological studies have shown that individuals with periodontitis have a significantly increased risk of developing coronary heart disease. In addition to conventional risk factors, chronic infection and subsequent production of systemic inflammatory markers may be associated with this increased risk.

OBJECTIVES

The aim of the present study was to determine whether the presence of chronic periodontitis and subsequent periodontal treatment could influence the serum levels of C-reactive protein (CRP), interleukin-6 and tumor necrosis factor-alpha (TNF-alpha) in a Japanese population.

METHODS

Sera were obtained from 24 patients with moderate to advanced periodontitis at the baseline examination and at reassessment after completion of treatment. As a control, sera were also obtained from 21 subjects without periodontitis. High-sensitivity CRP (hs-CRP) was measured using nephelometry with a latex particle-enhanced immunoassay and interleukin-6 and TNF-alpha were determined by sensitive enzyme-linked immunosorbent assay.

RESULTS

The levels of hs-CRP and interleukin-6 in the sera of this Japanese population seemed to be much lower than those reported in other populations. TNF-alpha on the other hand, demonstrated similar levels between this Japanese and other populations. Periodontal status demonstrated a significant improvement in all patients following treatment. There was a trend toward higher hs-CRP levels in patients at baseline compared with control subjects. Hs-CRP level tended to decrease with improvement of the periodontal condition following treatment and approached that of control subjects, although this decline was not statistically significant. interleukin-6 and TNF-alpha levels did not change following periodontal treatment. Furthermore, there was no difference in the serum levels of these inflammatory cytokines between patients either at baseline or at reassessment and control subjects.

CONCLUSIONS

In this pilot study, we were unable to show that periodontal disease significantly affects the serum levels of systemic inflammatory markers. However, this does not necessarily mean that periodontitis does not contribute to the total burden of inflammation as there was a tendency for hs-CRP to decrease following successful periodontal treatment. Large-scale studies are clearly needed to determine the impact of periodontal disease on systemic inflammation.

Effects of Porphyromonas gingivalis antigens and proinflammatory cytokines on human coronary artery endothelial cells

OBJECTIVE

Individuals with periodontitis have been cited as having a significantly increased risk of developing coronary heart disease. Although accumulating evidence suggests that periodontal infection is involved in the development and progression of atherosclerosis, the underlying mechanisms remain to be elucidated. In the present study, we examined how periodontal infection could contribute to endothelial dysfunction.

METHODS

Human coronary arterial endothelial cells were stimulated with tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta, both of which are reported to be elevated in the serum of periodontitis patients. Cells were also stimulated with lipopolysaccharide, outer membrane protein and heat shock protein 60 derived from Porphyromonas gingivalis, a representative periodontopathic bacterium which is known to stimulate myeloid cells.

RESULTS

Although TNF-alpha and IL-1beta, at concentrations a little higher than those in sera of periodontitis patients, up-regulated the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, P. gingivalis antigens had only a slight stimulatory effect.

CONCLUSION

Experiments in which the total pathogen burden is considered, rather than a single species of bacteria, would increase our understanding of the contribution of which periodontal infection to atherogenesis.

Capnocytophagaspp. in Periodontitis Patients Manifesting Diabetes Mellitus

BACKGROUND

The subgingival microflora in patients presenting concurrently with periodontitis and diabetes mellitus (DM) are poorly understood. While traditional putative periodontal pathogens are implicated, research involving other oral organisms; e.g., Capnocytophaga spp., is lacking. These organisms produce a range of bacterial enzymes relevant to periodontal breakdown. It is inferred that periodontal bacteria acquire systemic access through the ulcerated periodontal pocket surface; conclusive evidence supporting this notion is limited. The aims of this investigation were to: 1) quantify and identify Capnocytophaga spp. present in healthy and diseased sites in periodontitis patients with and without DM, and 2) isolate periodontal pathogens from these patients' blood.

METHODS

Twenty-one DM-periodontitis and 25 periodontitis patients were recruited. Subgingival plaque was collected from three healthy and three diseased sites per subject. Capnocytophaga spp. and total (facultative and obligate) anaerobic counts from each site were estimated. Capnocytophaga spp. were identified using 16S rRNA polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP). Statistical analyses were performed using multilevel modeling. Blood samples were subjected to HbA(1c) estimation and bacterial culture.

RESULTS

A total of 848 Capnocytophaga spp. were isolated and identified. Significantly higher numbers of Capnocytophaga spp. (P <0.001) and anaerobes (P <0.001) were present in diseased sites in DM-periodontitis subjects compared to healthy sites in non-DM-periodontitis and DM-periodontitis subjects. C. ochracea (and variant) and C. granulosa were the most prevalent species. Blood samples were negative for Capnocytophaga spp.

CONCLUSIONS

Total mean counts for Capnocytophaga spp. were significantly higher in DM-periodontitis subjects versus non-DM-periodontitis (P = 0.025) and at diseased sites versus healthy sites (P <0.001). Analysis of individual species revealed that the outcome varied with site status and DM status.

Prevalence of Periodontopathic Bacteria in Aggressive Periodontitis Patients in a Chilean Population

BACKGROUND

Actinobacillus actinomycetemcomitans is considered a major etiologic agent of aggressive periodontitis (AgP). Other periodontopathic bacteria such as Porphyromonas gingivalis are also suspected of participating in aggressive periodontitis although the evidence to support this is controversial. The aim of the present study was to determine the prevalence of eight periodontopathic bacteria in Chilean patients with AgP.

METHODS

Subgingival plaque samples were collected from 36 aggressive, 30 localized, and six generalized periodontitis patients. Samples from 17 advanced chronic periodontitis (CP) patients were taken as controls. Samples collected from the four deepest periodontal pockets in each patient were pooled in prereduced transport fluid (RTF) and cultured. Periodontal bacteria were primarily identified by colony morphology under stereoscopic microscope and rapid biochemical tests. The identity of some bacterial isolates was confirmed by colony polymerase chain reaction (PCR).

RESULTS

AgP showed a significatively higher prevalence of C. rectus than CP (P = 0.036). The only statistical difference found was for C. rectus. Patients with AgP showed a higher, but not statistically significant, prevalence of P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. A similar prevalence in both groups of patients was observed for F. nucleatum and P. intermedia/nigrescens, and A. actinomycetemcomitans was less prevalent in AgP than CP patients. In localized AgP, P. intermedia/nigrescens, E. corrodens, F. nucleatum, and P. micros were the more prevalent pathogens in contrast to generalized AgP patients who harbored A. actinomycetemcomitans, P. gingivalis, and Capnocytophaga sp. as the most prevalent bacteria.

CONCLUSIONS

C. rectus, P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. were the most predominant periodontopathic bacteria of AgP in this Chilean population, but the only statistical difference found here between AgP and CP was for C. rectus, suggesting that the differences in clinical appearance may be caused by factors other than the microbiological composition of the subgingival plaque of these patients. In this study, the prevalence of A. actinomycetemcomitans was much lower than that of P. gingivalis.

Association of periodontal disease to anxiety and depression symptoms, and psychosocial stress factors

OBJECTIVE

A cross-sectional study was conducted to investigate if anxiety, depression and hopelessness symptoms are associated with periodontal disease.

METHOD

A total of 160 subjects took part in this study. Probing depth and clinical attachment level were recorded at six sites per tooth and the gingival and plaque indices were also recorded. The instruments used to assess the psychological variables (anxiety, depression, stress, psychiatric symptoms and hopelessness) were: the State-Trait Anxiety Inventory, the Beck Depression Inventory, the Life Events Scale modified by Savoia, the Self-Report Screening Questionnaire-20 and the Beck Hopelessness Scale.

RESULTS

There was no difference in scale score means between patients with and without established periodontitis. Results of the Ordinal Logistic Regression Analysis model that included age, plaque index, smoking and psychological factors showed that patients with psychiatric symptoms (odds ratio (OR) 1.24, 95% confidence interval (CI) 0.33-4.78), depression symptoms (OR 0.57, 95% CI 0.15-2.21) and with hopelessness (OR 0.70, 95% CI 0.13-3.84) were not at a greater risk of developing established periodontitis.

CONCLUSION

In this sample, no evidence was found for an association between depression, hopelessness, psychiatric symptoms and established periodontitis. The association of periodontal disease to depression, anxiety and stress should be investigated in psychiatric populations, especially in those with depression and anxiety disorders.

The association of periodontal disease parameters with systemic medical conditions and tobacco use

OBJECTIVES

The objective of this study was to determine if an association existed between periodontal disease and various systemic medical conditions and tobacco use.

MATERIAL AND METHODS

The study design was a case-controlled, retrospective chart review. Patient charts (n=2006) were selected from more than 13,000 active patients attending the University of Minnesota dental clinics. These charts were examined to determine patient's self-reported systemic condition and smoking history. In addition, the number of missing teeth and bone loss were recorded. Two examiners collected the data. One examiner abstracted patient's medical history from the standard clinic medical questionnaire. The second examiner assessed the radiographs and dental charts to determine bone loss and number of missing teeth. Each examiner was blind to the findings of the other.

RESULTS

After adjusting for age, sex, diabetes and smoking (yes/no) status, seven conditions were significantly (p=0.0003-0.04) related to bone loss or number of missing teeth (vascular disease, heart surgery, vascular surgery, heart attack, thyroid problems, arthritis, stomach ulcers). From these conditions, thyroid problems and arthritis had a negative association with bone loss.

CONCLUSIONS

These findings support the results from previous investigators that a number of systemic conditions and smoking are closely associated with missing teeth or bone loss.

Periodontitis and atherogenesis: causal association or simple coincidence?

OBJECTIVES

The aim of this study was to assess the systemic effects of treating severe widespread periodontitis in a population of otherwise healthy individuals by examining treatment associated changes in markers of inflammation that are also implicated in cardiovascular atherosclerotic diseases. The potential impact of specific polymorphisms in cytokine genes known to influence both periodontitis and cardiovascular diseases was also examined.

MATERIALS AND METHODS

A convenience sample of patients affected with severe generalised periodontitis was enrolled into a prospective single blind longitudinal intervention trial with a 6 months follow-up. Serum C-reactive protein (CRP) and interleukin-6 (IL-6) levels were assessed by high-sensitivity assays. Serological and clinical periodontal parameters were evaluated at baseline, 2 and 6 months after completion of non-surgical periodontal therapy.

RESULTS

In the 94 subjects that completed this pilot trial improvements in all clinical periodontal parameters were achieved. These were accompanied with significant reductions in serum IL-6 and CRP concentrations. In a multivariate model, serum CRP levels were significantly associated with the outcome of periodontal treatment after correcting for potential covariates (age, body mass index, gender, smoking) and polymorphisms in the IL-6 (-174 C/G) and IL-1A (-889) genes. A median decrease in serum CRP of 0.5 mg/l (95% CI 0.4-0.7 mg/l) was observed 6 months after completion of periodontal therapy in this population. Subjects with above average response to periodontal therapy (<30 residual pockets and <30% of sites bleeding on probing) accounted for the observed improvement in serum CRP.

CONCLUSIONS

Control of periodontitis, achieved with non-surgical periodontal therapy, significantly decreased serum mediators and markers of acute phase response. The significance of the serum response was associated with the half of the population that responded better to non-surgical periodontal therapy. The results of this pilot study indicate that severe generalised periodontitis causes systemic inflammation. This is consistent with a causative role of periodontitis in atherogenesis.

The Short-Term Effects of Treatment of Chronic Periodontitis on Circulating Levels of Endotoxin, C-Reactive Protein, Tumor Necrosis Factor-α, and Interleukin-6

BACKGROUND

The acute-phase response involves molecules including tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and C-reactive protein (CRP). This study aimed to determine whether subgingival scaling resulted in rapid changes in plasma concentrations of these molecules.

METHODS

Twenty-three non-smoking adults with chronic periodontitis received subgingival scaling for 60 minutes. Venous blood samples were taken at 0, 15, 30, 60, and 120 minutes. TNF-alpha and IL-6 were assayed from all samples and CRP from the baseline and final samples. Lipopolysaccharide (LPS) was assayed at 0, 15, and 30 minutes using limulus lysate assay (LAL) and EndoCAb Ig assays.

RESULTS

LPS assays were suggestive of a transient low-grade bacteremia, but changes in LPS approaching significance (P=0.061) were seen with LAL only. There was a significant increase in circulating TNF-alpha (P=0.0387) and IL-6 (P<0.0001), and the degree of change in TNF-alpha was correlated with the severity of periodontal breakdown (P=0.001). There was also a significant correlation between levels of IL-6 and TNF-alpha (P<0.001).

CONCLUSIONS

Chronic periodontitis patients undergoing an episode of subgingival scaling show a significant elevation in circulating TNF-alpha and IL-6. This may account for anecdotal reports of pyrexia following treatment and may be significant in terms of the relationship between periodontal disease, bacteremia, and cardiovascular disease.

Periodontal disease and diabetes mellitus

Infections of the tissue surrounding the teeth (periodontitis) are usually caused by anaerobic gram-negative microorganisms. This infection causes destruction of the supporting alveolar bone and can lead to tooth loss. Removal of these microorganisms can slow or arrest the progression of periodontitis. Diabetes patients are at greater risk of developing periodontitis, may not respond as well to periodontal therapy as nondiabetic patients, and may require more aggressive treatment to manage periodontitis. Microorganisms that cause periodontitis and the host response to these may increase insulin resistance in diabetic patients. Treatment of periodontitis could improve glycemic control. A model is presented in which periodontal pathogens may cause increases in proinflammatory cytokines that mediate increases in insulin resistance, resulting in an increase in blood glucose. Following periodontal therapy, this process may be reversed.

Influence of implant microstructure on the dynamics of bone healing around immediate implants placed into periodontally infected sites. A confocal laser scanning microscopic study

This study evaluated by fluorescence analysis the influence of implant microstructure on the placement of immediate implants in periodontally infected sockets. Periodontal disease was induced during 12 weeks bilaterally from P1 to P4 in six dogs. The teeth were extracted and immediate implants were placed. Each dog received six implants: three with Friadent experimental surface (grit blasted/acid etched - FES group) and three covered with titanium plasma spray (TPS group), for a total of 36 Frialit-2 stepped cylinder implants. During the healing period, fluorescent bone markers were injected to study the bone remodeling around the implants. The dyes were injected in the following sequence: oxytetracyclin hydrochloride 3 days and 8 weeks, calcein green 4 weeks after the implantation and alizarin red S 3 days before killing. The animals were anesthetized and killed 12 weeks after implant placement. The mandibles were removed, dissected and processed for analyses of the percentage of newly formed bone surrounding the implant using a confocal laser scanning microscope. There were no significant statistical differences in bone formation (Mann-Whitney) between groups (FES group: 5.28% formation at 3 days, 10.3% at 4 weeks, 21.14% at 8 weeks and 6.98% at 12 weeks; TPS group: 3.36% at 3 days, 9.58% at 4 weeks, 14.57% at 8 weeks and 7.08% at 12 weeks). However, covariance analysis showed that the percent of marked bone was statistically greater for the FES group when compared to the TPS group, between the 3-day and 8-week periods of evaluation.

Effects of Tumor Necrosis Factor-α Inhibitors Pentoxifylline and Thalidomide on Alveolar Bone Loss in Short-Term Experimental Periodontal Disease in Rats

BACKGROUND

Pentoxifylline (PTX) and thalidomide (TLD) have been shown to inhibit cytokine synthesis, mainly tumor necrosis factor (TNF)-alpha, in different inflammatory conditions. We studied the effects of these cytokine inhibitors in an experimental model of periodontitis.

METHODS

Wistar rats were subjected to a ligature placement around the second upper right molars. Alveolar bone loss was evaluated by the sum of the distances between the cusp tip and the alveolar bone along the axis of each molar root, subtracting from the contralateral side. Histopathological analysis was based on cell influx, amount of alveolar bone, and cementum integrity. Animals were weighed daily, and total and differential peripheral white blood cell counts were performed at 6 hours and 1, 7, and 11 days after induction of periodontitis. Groups were treated with saline (positive control), PTX, or TLD 1 hour before and daily up to 11 days after induction of periodontitis.

RESULTS

Alveolar bone loss was inhibited 42%, 54%, and 69% by PTX at 5, 15, and 45 mg/kg, and 25%, 25%, 42%, and 54% by TLD at 5, 15, 45, and 90 mg/kg, respectively, as compared to the control (P < 0.05; analysis of variance). Histological analysis showed that PTX and TLD reduced cell influx and alveolar bone and cementum destruction. PTX and TLD also reversed peripheral lymphomonocytosis but not weight loss, as compared to controls. These data showed that both PTX and TLD reduced alveolar bone loss in periodontitis.

CONCLUSION

The data showed a protective effect of PTX and TLD on experimental periodontitis, suggesting a role for TNF-alpha in the pathophysiology of periodontitis.

An investigation into the association among preterm birth, cytokine gene polymorphisms and periodontal disease

OBJECTIVE

To investigate a putative relationship between preterm delivery and the carriage of polymorphic genes that code for the cytokines interleukin-1beta (IL-1beta) at codon +3953 and tumour necrosis factor-alpha (TNF-alpha) at codon -308 in a group of postpartum women and to elucidate if the concurrent presence of periodontal disease increased the risk of preterm delivery in this group.

DESIGN

Case-control study

SETTING

Postnatal wards at Guy's and St Thomas' Hospital Trust.

POPULATION

Postpartum women from southeast London, UK.

METHODS

Case subjects were defined as those who experienced a birth at less than 37 weeks of gestation. Control subjects gave birth at term. Demographic data were collected and a periodontal examination was performed. Blood samples were collected and analysed by restriction fragment length polymerase techniques for the presence of each of the allelic variants.

MAIN OUTCOME MEASURES

The level of periodontal disease and the carriage of allelic variants of IL-1beta+3953 and TNF-alpha-308 genes.

RESULTS

Forty-eight case subjects and 82 control subjects were assessed. There was no statistically significant difference in the carriage of the IL-1beta+3953 allelic variant between cases and controls (29%versus 18%, P= 0.112). However, 23 (48%) of the case subjects and 24 (29%) of controls were heterozygous or homozygous for the variant TNF-alpha-308 gene (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.0-5.0, P= 0.026). There was no association between the carriage of either the polymorphic IL-1beta+3953 or TNF-alpha-308 variant and the severity of periodontal disease. The combination of periodontal disease and the allelic variant did not increase the risk of preterm delivery.

CONCLUSIONS

In this study, a higher proportion of women who delivered preterm carried the polymorphic TNF-alpha-308 gene. There did not appear to be any interaction between either of the genotypes and periodontal disease with preterm delivery as has been reported for bacterial vaginosis and the TNF-alpha-308 polymorphic gene.

Potential role of vascular endothelial growth factor, interleukin-8 and monocyte chemoattractant protein-1 in periodontal diseases

Host-mediated immunoinflammatory pathways activated by bacteria lead to destruction of the periodontal connective tissues and alveolar bone. The objective of this study was to elucidate the activation of the inflammatory processes in periodontal disease by quantitative assessment of cytokines and periodontopathogens. Gingival crevicular fluids (GCF) and subgingival plaque samples were collected from patients with chronic periodontitis and gingivitis and from periodontally healthy sites. Vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), and interleukin 8 (IL-8) in GCF were analyzed by enzyme-linked immunosorbent assay. Periodontopathogens, including Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis and Prevotella intermedia, were analyzed by immunofluorescence and dark-field microscopy. There was significantly more VEGF and IL-8 in chronic periodontitis and gingivitis sites than in periodontally healthy sites. There were significant positive correlations between the concentrations and total amounts of VEGF and IL-8 in chronic periodontitis and gingivitis sites, and between the levels of periodontopathogens and the total amounts of VEGF, MCP-1 and IL-8. These data indicate that inflammatory processes induced by periodontopathogens and the activation of certain cytokines (VEGF, MCP-1, IL-8) in periodontal diseases may be relevant to host-mediated destruction in chronic periodontitis.

Effect of treatment of chronic periodontitis on levels of serum markers of acute-phase inflammatory and vascular responses

AIMS

Recent epidemiological work suggests an association between periodontal disease severity and cardiovascular disease risk. This study aimed to ascertain if circulating levels of cardiovascular and systemic inflammatory markers could be modified following treatment of periodontal disease.

METHOD

Adult subjects were recruited from those awaiting periodontal treatment and randomised to either immediate (test, n=24) or delayed treatment (control, n=15). Demographic and clinical data were collected and venous blood was taken before and either 6 weeks after completion of treatment or after an equivalent 3-month control period. Periodontal examination included probing depth, loss of attachment, plaque scores and bleeding scores. Blood was analysed to determine serum and plasma fibrinogen, C-reactive protein, sialic acid, tumour necrosis factor-alpha and interleukin -6 and -1beta. Effects of treatment were assessed by paired tests and analysis of variance by treatment group with baseline covariates.

RESULTS

Treatment improved plaque and bleeding scores and reduced probing depths (p<0.002). However, there were no statistically significant changes in levels of any of the systemic markers.

CONCLUSION

Improvement in periodontal health did not influence the levels of vascular markers.

[Does periodontal disease cause cardiovascular disease? Analysis of epidemiological evidences]

This article reports a critical analysis of epidemiologic studies that evaluated periodontal disease as a cause of cardiovascular disease. Thirty-five studies were identified through a manual search of the special abstracts volumes of the Journal of Dental Research, as well as an electronic search on MEDLINE, LILACS, and ISI and inspection of the articles' bibliographies. Inclusion criteria were: articles in any language published between 1989 and 2000 reporting the presence or absence of an association between periodontal and cardiovascular diseases. Available studies are scarce, and interpretations are limited by potential bias and confounding. The studies analyzed (whether separately or jointly) fail to provide convincing epidemiologic evidence for a causal association between periodontal and cardiovascular diseases. Although the possibility that oral diseases can cause cardiovascular diseases cannot be discarded, until better data are available, periodontal disease should not be incriminated as a cause of cardiovascular disease.

Innate secretory immunity in response to laboratory stressors that evoke distinct patterns of cardiac autonomic activity

OBJECTIVE

Most infections begin at mucosal surfaces. These surfaces are covered by the secretory proteins of the exocrine glands (eg, the salivary, respiratory, and gastrointestinal glands), which provide a first line of innate defense. The release of these secretory proteins is under neuroendocrine control and thus, in theory, sensitive to modulation by psychosocial stress. This was empirically tested by measuring the salivary secretion of cystatin S, lactoferrin, alpha-amylase, the mucins MUC5B and MUC7, and total salivary protein in response to stressors known to evoke distinct patterns of cardiac autonomic activity.

METHODS

Thirty-two undergraduate volunteers were each subjected to two laboratory stressors and a control condition. Stressors were an active coping memory test and a passive coping video presentation showing surgical procedures. In the control condition participants viewed a didactic video presentation.

RESULTS

The stressors evoked the expected distinct patterns of cardiac autonomic activity. The memory test produced a strong increase in sympathetic activity (evidenced by a shortened preejection period), and a decrease in cardiac parasympathetic activity (evidenced by a decrease in heart rate variability). This active coping response was associated with an enhanced secretion ( microg/min, controlling for salivary flow rate) of MUC7, lactoferrin, alpha-amylase, and total salivary protein. Conversely, the surgical video produced an increase in cardiac vagal tone and a modest increase in sympathetic activity. This passive coping response was associated with an enhanced secretion of all proteins studied. These secretory responses were generally larger than the secretory responses during the active coping memory test. Correlation analyses indicated that for both stressors autonomic and cardiovascular reactivity was positively associated with an enhanced and prolonged secretory activity.

CONCLUSIONS

Stress-induced modulation of innate secretory immunity may be a contributing factor in the observed relationship between stress and susceptibility to infectious diseases. We further propose a more differentiated approach to acute stress by distinguishing among stressors with distinct autonomic nervous system effects.

The pattern of alveolar crest height change in healthy postmenopausal women after 3 years of hormone/estrogen replacement therapy

BACKGROUND

The loss of ovarian function at menopause is associated with loss of postcranial and oral bone. Hormone/estrogen replacement therapy (HRT/ERT) has a positive effect on both postcranial and oral bone. The objective of the study was to determine if the positive effect of HRT/ERT on alveolar crest height (ACH) is generalized or site specific.

METHODS

The sample consisted of 49 women who completed a 3-year, HRT/ERT prospective study. Cemento-enamel junction distances (ACH) were measured on digitized images of bitewing radiographs. Lumbar spine and proximal femur bone mineral densities (BMDs) were determined with dual-energy x-ray absorptiometric scans. Measurements were made at baseline and at the end of year 3. For the 3-year study period, mean change in ACH was determined for each patient. In addition, the sites with the greatest, second and third greatest ACH changes were determined for each patient. Correlations between changes in ACH (as determined by the various methods) and postcranial BMD were determined.

RESULTS

Mean ACH changes had an average correlation (r) of -0.24 with femoral and lumbar spine BMDs. Although the largest site-specific change in ACH resulted in a mean correlation of -0.21, the correlations for the second and third largest changes in ACH dropped to -0.15 and -0.12. Overall, the correlations for site-specific changes were substantively smaller than those for generalized change.

CONCLUSIONS

The data of this study indicate that ACH change attributable to HRT/ERT is generalized rather than site specific. Studies of the effect of HRT/ERT on ACH should employ multiple measurements to minimize measurement errors associated with site-specific measurements.

PMN responses in chronic periodontal disease: evaluation by gingival crevicular fluid enzymes and elastase-alpha-1-proteinase inhibitor complex

OBJECTIVES

In the present trial, the hypothesis was examined that the local PMN responses in untreated and treated chronic periodontitis can be differentiated by gingival crevicular fluid lysosomal enzyme activities and elastase-alpha-1-proteinase inhibitor complex.

METHODS

In nine subjects (average age 49.2 +/- 7.1 years) with chronic periodontitis, clinical parameters and markers of the PMN-derived inflammatory tissue response in gingival crevicular fluid (GCF) were assessed before and 6 months after surgical periodontal therapy. Myeloperoxidase (MPO), beta-N-acetyl-hexosaminidase (beta-NAH) and cathepsin D (CD) were analyzed as indicators of the PMN-associated host tissue destruction, and elastase-alpha-1-proteinase inhibitor complex (alpha-1-EPI) as the major serum protein inactivating PMN elastase. The total activities of the lysosomal enzymes MPO and beta-NAH were evaluated spectrophotometrically, the CD levels by liquid scintillation counting with [14C] hemoglobin as substrate, and the total alpha-1-proteinase inhibitor complex using a sandwich-immunoassay.

RESULTS

The clinical parameters revealed a statistical significant decrease at the 6-month reexamination. PD levels dropped from 5.40 to 2.88 mm (change 2.52 +/- 1.04 mm), the CAL scores from 6.67 to 4.43 mm (change 2.24 +/- 0.77 mm). The 30 s GCF volumes dropped from 129.8 to 68.6, displaying a change of 61.1 +/- 18.6, p </= 0.05. The decrease in total MPO, beta-NAH and CD levels (medians: 1.7/0.6 micro U MPO, 0.035/0.020 micro U beta-NAH, 1.3/0.5 ng CD) following therapy was associated with a significant drop in total GCF amounts of alpha-1-EPI from 76.3 ng at baseline to 52.4 ng after 6 months.

CONCLUSION

The clinical healing in chronic periodontal disease is associated with a downregulation of the local PMN responses following periodontal therapy. The reorganization of periodontal tissues is characterized by a decrease of lysosomal enzyme activities and the alpha-1-proteinase inhibitor complex in gingival crevicular fluid.

Infectious complications of dental and periodontal diseases in the elderly population

Retention of teeth into advanced age makes caries and periodontitis lifelong concerns. Dental caries occurs when acidic metabolites of oral streptococci dissolve enamel and dentin. Dissolution progresses to cavitation and, if untreated, to bacterial invasion of dental pulp, whereby oral bacteria access the bloodstream. Oral organisms have been linked to infections of the endocardium, meninges, mediastinum, vertebrae, hepatobiliary system, and prosthetic joints. Periodontitis is a pathogen-specific, lytic inflammatory reaction to dental plaque that degrades the tooth attachment. Periodontal disease is more severe and less readily controlled in people with diabetes; impaired glycemic control may exacerbate host response. Aspiration of oropharyngeal (including periodontal) pathogens is the dominant cause of nursing home-acquired pneumonia; factors reflecting poor oral health strongly correlate with increased risk of developing aspiration pneumonia. Bloodborne periodontopathic organisms may play a role in atherosclerosis. Daily oral hygiene practice and receipt of regular dental care are cost-effective means for minimizing morbidity of oral infections and their nonoral sequelae.

Modulation of the host response in periodontal therapy

This paper was prepared by the Research, Science, and Therapy Committee of the American Academy of Periodontology to provide the dental profession an overview of current and potential methods to modulate the host response in the treatment of periodontal diseases. Specifically, it discusses components of periodontal disease pathogenesis (i.e., immune and inflammatory responses, excessive production of matrix metalloproteinases and arachidonic acid metabolites, and regulation of bone metabolism) and their modulation.

Treatment of periodontitis by local administration of minocycline microspheres: a controlled trial

BACKGROUND

Periodontitis is an inflammatory condition of tooth-supporting tissues that is usually treated by mechanical removal of plaque and microorganisms that adhere to teeth. This treatment, known as scaling and root planing, is not optimally effective. Adjunctive therapy with locally delivered antimicrobials has resulted in improved clinical outcomes such as probing depth reduction. This article reports on the efficacy and safety of locally administered microencapsulated minocycline.

METHODS

Seven hundred forty-eight (748) patients with moderate to advanced periodontitis were enrolled in a multi-center trial and randomized to 1 of 3 treatment arms: 1) scaling and root planing (SRP) alone; 2) SRP plus vehicle; or 3) SRP plus minocycline microspheres. The primary outcome measure was probing depth reduction at 9 months. Clinical assessments were performed at baseline and 1, 3, 6, and 9 months.

RESULTS

Minocycline microspheres plus scaling and root planing provided substantially more probing depth reduction than either SRP alone or SRP plus vehicle. The difference reached statistical significance after the first month and was maintained throughout the trial. The improved outcome was observed to be independent of patients' smoking status, age, gender, or baseline disease level. There was no difference in the incidence of adverse effects among treatment groups.

CONCLUSIONS

Scaling and root planing plus minocycline microspheres is more effective than scaling and root planing alone in reducing probing depths in periodontitis patients.

Nonhuman primates: a critical role in current disease research

This review article emphasizes the critical role of nonhuman primates (NHPs) in biomedical research. It focuses on the most recent contributions that NHPs have made to the understanding, treatment, and prevention of important infectious diseases (e.g., acquired immunodeficiency syndrome, hepatitis, malaria) and chronic degenerative disorders of the central nervous system (e.g., Parkinson's and Alzheimer's diseases). The close phylogenetic relation of NHPs to humans not only opens avenues for testing the safety and efficacy of new drugs and vaccines but also offers promise for evaluating the potential of new gene-based treatments for human infectious and genetic diseases.

Activation of protease-activated receptors by gingipains from Porphyromonas gingivalis leads to platelet aggregation: a new trait in microbial pathogenicity

The bacterium Porphyromonas gingivalis is a major etiologic agent in the pathogenesis of adult periodontitis in humans. Cysteine proteinases produced by this pathogen, termed gingipains, are considered to be important virulence factors. Among many other potentially deleterious activities, arginine-specific gingipains-R (RgpB and HRgpA) efficiently activate coagulation factors. To further expand knowledge of the interaction between gingipains and the clotting cascade, this study examined their effects on cellular components of the coagulation system. The enzymes induced an increase in intracellular calcium in human platelets at nanomolar concentrations and caused platelet aggregation with efficiency comparable to thrombin. Both effects were dependent on the proteolytic activity of the enzymes. Based on desensitization studies carried out with thrombin and peptide receptor agonists, and immunoinhibition experiments, gingipains-R appeared to be activating the protease-activated receptors, (PAR)-1 and -4, expressed on the surface of platelets. This was confirmed by the finding that HRgpA and RgpB potently activated PAR-1 and PAR-4 in transfected cells stably expressing these receptors. Cumulatively, the results indicate the existence of a novel pathway of host cell activation by bacterial proteinases through PAR cleavage. This mechanism not only represents a new trait in bacterial pathogenicity, but may also explain an emerging link between periodontitis and cardiovascular disease. (Blood. 2001;97:3790-3797)

Activation of human prothrombin by arginine-specific cysteine proteinases (Gingipains R) from porphyromonas gingivalis

The effect of 95- (HRgpA) and 50-kDa gingipain R (RgpB), arginine-specific cysteine proteinases from periodontopathogenic bacterium Porphyromonas gingivalis on human prothrombin activation was investigated. Each enzyme released thrombin from prothrombin in a dose- and time-dependent manner with the former enzyme, containing adhesion domains, being 17-fold more efficient than the single chain RgpB. A close correlation between the generation of fibrinogen clotting activity and amidolytic activity indicated that alpha-thrombin was produced by gingipains R, and this was confirmed by SDS-polyacrylamide gel electrophoresis, thrombin active site labeling, and amino-terminal sequence analysis of prothrombin digestion fragments. Significantly, the catalytic efficiency of HRgpA to generate thrombin (k(cat)/K(m) = 1.2 x 10(6) m(-)1 s(-)1) was 100-fold higher than that of RgpB (k(cat)/K(m) = 1.2 x 10(4) m(-)1 s(-)1). The superior prothrombinase activity of HRgpA over RgpB correlates with the fact that only the former enzyme was able to clot plasma, and kinetic data indicate that prothrombin activation can occur in vivo. At P. gingivalis-infected periodontitis sites HRgpA may be involved in the direct production of thrombin and, therefore, in the generation of prostaglandins and interleukin-1, both have been found to be associated with the development and progression of the disease. Furthermore, by taking into account that the P. gingivalis bacterium has been immunolocalized in carotid atherosclerotic plaques at thrombus formation sites (Chiu, B. (1999) Am. Heart J. 138, S534-S536), our results indicate that bacterial proteinases may potentially participate in the pathogenesis of cardiovascular disease associated with periodontitis.

The effect of antimicrobial periodontal treatment on circulating tumor necrosis factor-alpha and glycated hemoglobin level in patients with type 2 diabetes

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) may play an important role in insulin resistance. In this study, we hypothesized that TNF-alpha produced due to periodontal inflammation synergistically affects insulin resistance as well as TNF-alpha produced from adipose tissues in insulin-resistant type 2 diabetes patients. Therefore, to understand the effects of antimicrobial periodontal therapy on serum TNF-alpha concentration and subsequent metabolic control of diabetes, we examined the periodontal and diabetic status on 13 type-2 diabetes patients.

METHODS

These patients were treated with local minocycline administration in every periodontal pocket around all existing teeth once a week for a month. Before and after treatment, the number of total bacteria in the periodontal pockets and circulating TNF-alpha concentration were measured and the HbA1c value was assessed.

RESULTS

Antimicrobial therapy significantly reduced the number of microorganisms in periodontal pockets (P <0.01). After treatment, the circulating TNF-alpha level was significantly reduced (P <0.015). The HbA1c value was also reduced significantly (P <0.007). In addition, the 6 patients who were not receiving insulin therapy demonstrated decreased fasting insulin levels (P <0.03), and HOMA-R (P <0.03) indices. The average reductions in circulating TNF-alpha concentration and HbA1c value were 0.49 pg/ml and 0.8%, respectively.

CONCLUSION

The results indicate that anti-infectious treatment is effective in improving metabolic control in diabetics, possibly through reduced serum TNF-alpha and improved insulin resistance.

Activation of blood coagulation factor IX by gingipains R, arginine-specific cysteine proteinases from Porphyromonas gingivalis

The effect of two arginine-specific cysteine proteinases (gingipains R) from Porphyromonas gingivalis, an aetiological factor of adult periodontitis, on the activation of human factor IX was investigated in the presence of ethylene glycol, an activity enhancer of activated factor IX (factor IXa), with the use of a fluorogenic oligopeptide substrate. Each gingipain R rapidly activated factor IX but the 95 kDa proteinase complex (HRgpA) that contains both haemagglutinin/adhesion and catalytic domains was 2.4-fold more efficient than the single-chain 50 kDa gingipain R (RgpB), which has only a catalytic domain. SDS/PAGE and N-terminal sequence analysis of factor IX digestion fragments indicated that, like all endogenous activators, gingipains R also produce factor IXabeta via an IXa intermediate. Significantly, phospholipids augmented the activation of factor IX by HRgpA but not by RgpB in a Ca(2+)-dependent manner. In the presence of both cofactors the kinetic efficiency of HRgpA to activate factor IX (k(cat)/K(m)=1.9x10(6) M(-1).s(-1)) was 8.5-fold higher than that of RgpB (k(cat)/K(m)=2.3x10(5) M(-1).s(-1)) and double that of the factor VIIa-tissue factor complex, but 8-fold lower than that for factor XIa. A comparison of the relative activation rates of factor IX, factor X and prothrombin directly in plasma by HRgpA suggests a significant contribution for factor IX conversion in blood coagulation induced by gingipains R. Taken together, gingipains R are the first-reported activators of factor IX of bacterial origin. By this effect they could be involved in the production of thrombin as well as the subsequent generation of prostaglandins and interleukin 1, all of which have been found to be associated with the development and progression of periodontitis.

Herpesviruses in HIV-periodontitis

BACKGROUND/AIMS

Human herpesvirus-associated diseases exhibit elevated morbidity and mortality in patients infected with human immunodeficiency virus (HIV). This study aimed to investigate the occurrence of herpesviruses in HIV-periodontitis.

METHOD

Gingival biopsies from periodontitis lesions of 21 HIV-patients and 14 non HIV-patients were studied. Nested-polymerase chain reaction methods were employed to detect human cytomegalovirus, Epstein-Barr virus type 1 and 2 (EBV-1, EBV-2), herpes simplex virus, human herpes virus (HHV)-6, HHV-7 and HHV-8.

RESULTS

Gingival biopsies from HIV-periodontitis lesions showed on average 4.0 herpesvirus species and gingival biopsies from HIV periodontitis lesions of non-HIV patients revealed an average of 1.9 herpesvirus species (p<0.001). Occurrence of 4 to 6 different herpesviruses was more common in HIV- than in non HIV-gingival biopsies (71% vs. 7%) (p<0.001). EVB-2 was detected in 12 (57%) biopsies from HIV-periodontitis but was absent in non HIV-periodontitis biopsies (p= 0.002). HHV-6 also occurred in significantly higher frequency in HIV-periodontitis (71%) than in non HIV-periodontitis (21%) (p=0.01). HHV-8 was detected only in biopsies from HIV-periodontitis lesions..

CONCLUSION

HIV-periodontitis seems to be associated with elevated occurrence of EBV-2, HHV-6 and herpesvirus co-infections compared to periodontitis in non-HIV-patients. The periodontopathic significance of herpesviruses in HIV-periodontitis constitutes a research topic of considerable interest.

Systemic diseases caused by oral infection

Recently, it has been recognized that oral infection, especially periodontitis, may affect the course and pathogenesis of a number of systemic diseases, such as cardiovascular disease, bacterial pneumonia, diabetes mellitus, and low birth weight. The purpose of this review is to evaluate the current status of oral infections, especially periodontitis, as a causal factor for systemic diseases. Three mechanisms or pathways linking oral infections to secondary systemic effects have been proposed: (i) metastatic spread of infection from the oral cavity as a result of transient bacteremia, (ii) metastatic injury from the effects of circulating oral microbial toxins, and (iii) metastatic inflammation caused by immunological injury induced by oral microorganisms. Periodontitis as a major oral infection may affect the host's susceptibility to systemic disease in three ways: by shared risk factors; subgingival biofilms acting as reservoirs of gram-negative bacteria; and the periodontium acting as a reservoir of inflammatory mediators. Proposed evidence and mechanisms of the above odontogenic systemic diseases are given.

Systemic diseases caused by oral infection

Recently, it has been recognized that oral infection, especially periodontitis, may affect the course and pathogenesis of a number of systemic diseases, such as cardiovascular disease, bacterial pneumonia, diabetes mellitus, and low birth weight. The purpose of this review is to evaluate the current status of oral infections, especially periodontitis, as a causal factor for systemic diseases. Three mechanisms or pathways linking oral infections to secondary systemic effects have been proposed: (i) metastatic spread of infection from the oral cavity as a result of transient bacteremia, (ii) metastatic injury from the effects of circulating oral microbial toxins, and (iii) metastatic inflammation caused by immunological injury induced by oral microorganisms. Periodontitis as a major oral infection may affect the host's susceptibility to systemic disease in three ways: by shared risk factors; subgingival biofilms acting as reservoirs of gram-negative bacteria; and the periodontium acting as a reservoir of inflammatory mediators. Proposed evidence and mechanisms of the above odontogenic systemic diseases are given.

Pathophysiological relationships between periodontitis and systemic disease: recent concepts involving serum lipids

Periodontitis has been traditionally regarded as a chronic inflammatory oral infection. However, recent studies indicate that this oral disease may have profound effects on systemic health. The search for cellular/molecular mechanisms linking periodontitis to changes in systemic health and systemic physiology has resulted in the evolution of a new area of lipid research establishing linkages between existing multidisciplinary biomedical literature, recent observations concerning the effects of serum lipids on immune cell phenotype/function, and a heightened interest in systemic responses to chronic localized infections. There appears to be more than a casual relationship between serum lipid levels and systemic health (particularly cardiovascular disease, diabetes, tissue repair capacity, and immune cell function), susceptibility to periodontitis, and serum levels of pro-inflammatory cytokines. In terms of the potential relationship between periodontitis and systemic disease, it is possible that periodontitis-induced changes in immune cell function cause metabolic dysregulation of lipid metabolism through mechanisms involving proinflammatory cytokines. Sustained elevations of serum lipids and/or pro-inflammatory cytokines may have a serious negative impact on systemic health. The purpose of this paper is to present the background, supporting data, and hypotheses related to this concept. As active participants in this emerging and exciting area of investigation, we hope to stimulate interest and awareness among biomedical scientists and practitioners.

Enhanced interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha production by LPS stimulated human monocytes isolated from HIV+ patients

Periodontal disease and tooth loss is a common finding among advanced HIV+ patients. In addition to local oral lipopolysaccharide (LPS) stimulation, systemic up-regulation of monocyte pro-inflammatory cytokine secretion may also be involved in the pathogenesis of HIV disease. A study was undertaken to investigate IL-1beta, IL-6 and TNF-alpha production by resting and LPS stimulated monocytes isolated from HIV+ patients and also to investigate the relationship of the patient's HIV viral load status to the cytokine production. Whole blood samples in EDTA were collected from 39 HIV-1 infected patients and 20 age and sex matched uninfected controls. Plasma was separated by centrifugation. Viral load was determined using a quantitative RT-PCR. Monocytes were isolated by Ficoll-hypaque gradient separation followed by overnight plastic adherence. Cultured monocytes (1x10(6)/ml) were stimulated with LPS (1 microg/ml) of either P. gingivalis or F. nucleatum for 2, 8, 24 and 48 h and supernatant fluids were collected. IL-1beta, IL-6, and TNF-alpha levels in supernatant fluids were estimated by ELISA. Increased overall production of IL-1beta, IL-6 and TNF-alpha by LPS stimulated monocytes isolated from HIV-1 infected patients was observed when compared to HIV-1 uninfected controls. LPS stimulated monocytes from HIV-1 infected patients with high viral load (HVL) produced significant (p<0.05) elevations in these pro-inflammatory cytokines when compared to HIV-1 uninfected controls. Both LPS of P. gingivalis and F. nucleatum produced a comparable cytokine production by monocytes after 8 h of stimulation. These data suggest that enhanced IL-1beta, IL-6 and TNF-alpha is produced by monocytes/macrophages isolated from HVL HIV+ patients and may be involved in the overall pathogenesis of HIV-1 infection.

Apical periodontitis and related factors in an adult Lithuanian population

OBJECTIVES

The objectives of this investigation were to study determinants of apical periodontitis among Lithuanians who were 35 to 44 years old and to study possible associations between apical periodontitis, relevant general diseases, and perceived general health.

STUDY DESIGN

Information was collected from a randomly selected sample, consisting of 147 individuals from Vilnius, Lithuania. Aspects of oral and general health, health-related habits and attitudes, and social parameters were used as independent variables, with various aspects of apical periodontitis as the dependent variable. Associations were tested by regression analysis.

RESULTS

Apical periodontitis was highly prevalent in this Lithuanian population. Oral health-related variables showed the strongest association with apical periodontitis. Decayed and filled teeth scores were found to be strongly associated with periapical disease, and sound teeth were strongly associated with periapical health. In addition, behavioral variables were found to be important disease determinants.

CONCLUSIONS

Apical periodontitis appeared to be an oral health problem closely related to dental caries. No association could be detected between general diseases and apical periodontitis, but an association between perceived general health and apical periodontitis was demonstrated.

Periodontal disease and atherosclerotic cardiovascular disease: confounding effects or epiphenomenon?

Recent evidence suggests that periodontal disease may predispose to atherosclerotic cardiovascular disease. Data support mechanisms of host-derived local and systemic proinflammatory responses similar to atherosclerosis, consisting of monocytic-derived cytokines and other inflammatory mediators, which are induced by periodontal pathogens and its endotoxin, lipopolysaccharide. These mechanisms may contribute to the start of vascular endothelial dysfunction and further sequelae leading to atherosclerosis. Experimental evidence and biologic plausibility appear to support this proposal. However, clinical evidence from a MEDLINE search from January 1966-December 1999 proposed a weak or no correlation primarily due to confounding factors. The aim of care is to reduce vulnerable pathogens from the infected periodontium by standard treatment; however, new approaches appear promising. Increased awareness of a potential link among infective agents, immunoinflammatory processes, and atherosclerosis may clarify clinical implications.