The interleukin-1 genotype as a severity factor in adult periodontal disease

Diagnostic biomarkers for oral and periodontal diseases

This article provides an overview of periodontal disease diagnosis that uses clinical parameters and biomarkers of the disease process.This article discusses the use of biomarkers of disease that can be identified at the tissue, cellular, and molecular levels and that are measurable in oral fluids such as saliva and gingival crevicular fluid. Biomarkers identified from these biologic fluids include microbial, host response, and connective tissue-related molecules that can target specific pathways of local alveolar bone resorption. Future prospects for oral fluid-based diagnostics that use micro-array and microfluidic technologies are presented.

Linkage disequilibrium analysis of case-control data: an application to generalized aggressive periodontitis

Several studies have shown a role for the involvement of interleukin (IL)-1 gene cluster polymorphisms in the risk of periodontal diseases. In the present study, we tested polymorphisms, derived from genes of the IL-1 cluster, for association with generalized aggressive periodontitis (GAP) through both allelic association and by constructing a linkage disequilibrium (LD) map of the 2q13-14 disease candidate region. The IL-1RN (VNTR) genotype distribution observed was significantly different in GAP and control subjects (P=0.019). We also observed some evidence for an association between GAP and the IL-1B(+3953) polymorphism (P=0.039). The pattern of association in the region, represented as an LD map, identifies a recombination hot area between the IL-1B(+3953) and IL-1B(-511) polymorphisms. Multilocus modelling of association with disease gives a location for the peak association at the IL-1B(+3953) marker, although support for the peak is not significant. Haplotype analysis identifies a IL-1B(+3953)-IL-1B(-511) haplotype as having the lowest P-value in the region. Recognition of the presence of a recombination hot area between the IL-1B(+3953) and IL-1B(-511) polymorphisms will have an important bearing on future efforts to develop higher resolution SNP analysis in this region for both this and other diseases for which this cluster is implicated.

Evidence of a pharmacogenomic response to interleukin-l receptor antagonist in rheumatoid arthritis

Biological activity of the IL-1 system depends on the balance between two proinflammatory proteins (IL-1alpha and IL-1beta) and the related anti-inflammatory protein, the IL-1 receptor antagonist (IL-1Ra). The genes for these proteins lie within 430 kb on human chromosome 2. Based on a clinical trial of human recombinant IL-1ra in rheumatoid arthritis, we tested whether IL-1 genotype might be related to the likelihood of response to anti-IL-1 therapy. A positive response was defined as a reduction of at least 50% in the number of swollen joints by week 24, following treatment with either 150 mg/day IL-1ra or placebo. The response rate to treatment, independent of genotype, was 48% (44/91). A highly significant association was found between carriage of the rarer allele at IL1A(+4845) and response to treatment (P=0.0009; OR=4.85 (1.85,12.70)). The response rate in patients carrying this allele was 63.4% compared with 26.3% in noncarriers. A weaker association was found for IL1B(+3954) (P=0.02). There was a highly significant interaction between treatment (150 mg/day or placebo) and the composite genotype across IL1A(+4845) and IL1B(+3954) (P=7.6 x 10(-5)). No associations with IL-1 genotypes were found in patients receiving placebo. Thus, a significant pharmacogenomic effect was found in the treatment of RA patients with recombinant IL-1ra.

Association of T CD4 Lymphocyte Levels and Chronic Periodontitis in HIV-Infected Brazilian Patients Undergoing Highly Active Anti-Retroviral Therapy: Clinical Results

BACKGROUND

Controversial data regarding the association between immunosuppression and prevalence/ severity of periodontal diseases in HIV infection have been reported. Thus, the aim of this study was to test the hypothesis that lower T CD4 lymphocyte levels are not related to a higher prevalence of chronic periodontitis in HIV-infected Brazilians undergoing highly active anti-retroviral therapy (HAART).

METHODS

Sixty-four HIV-infected patients under HAART were classified as having chronic periodontitis; i.e., > or = three sites with probing depth (PD) and/or clinical attachment level (CAL) > or = 5 mm or periodontal healthy (no sites with PD > 3 mm and/or CAL > 4 mm). All subjects received conventional periodontal therapy. Bleeding on probing, plaque accumulation, PD, and CAL were registered at six sites/tooth at baseline and 4 months after therapy. Epidemiological features and levels of T CD4 lymphocytes were obtained from medical records. Significance of differences in periodontal clinical parameters within and between groups were determined using Wilcoxon signed-rank and Mann-Whitney or independent sample t tests. Associations between T CD4 levels and clinical parameters were determined using the chi square test.

RESULTS

Sixty-one percent of the HIV-infected patients represented AIDS cases, although 69% of them were periodontally healthy. The overall T CD4 lymphocyte mean levels was 333 +/- 254 cells/mm3 and viral load was 12,815 +/- 24,607 copies/mm3. Yet the prevalence of chronic periodontitis was relatively low (36%). In addition, patients with periodontitis presented a moderate disease (mean PD = 2.2 +/- 0.10; mean CAL = 2.6 +/- 0.13) and responded successfully to periodontal therapy. These subjects showed higher levels of T CD4 cells, but lower counts of neutrophils than periodontally healthy patients. Among periodontally healthy and chronic periodontitis patients, 41.7% and 22.9%, respectively, had low levels of T CD4 lymphocytes. No significant differences between periodontal status and epidemiological and immunological parameters were observed.

CONCLUSION

Based on these results, the hypothesis that lower T CD4 lymphocyte levels are not associated with higher prevalence of chronic periodontitis in HIV-infected Brazilians under HAART cannot be rejected.

Evaluation of the relationship between interleukin-1 gene cluster polymorphisms and early implant failure in non-smoking patients

OBJECTIVE

The aim of the present study was to investigate the relationship between specific polymorphisms of the interleukin-1 gene cluster and the early failure of osseointegrated implants.

MATERIAL AND METHODS

The subject population was composed by a test group comprising 28 non-smoking patients (mean age 52.7) that had suffered one or more early implant failures and by a control group consisting of 34 individuals (mean age 43.3) with one or more healthy implants. Genomic DNA from buccal mucosa was amplified by the polymerase chain reaction (PCR), followed by restriction fragment length polymorphism (RFLP) and submitted to polyacrylamide gel electrophoresis to distinguish the alleles of the interleukin-1A (-889), interleukin-1B (+3953), interleukin-1B (-511) and interleukin-RN (intron 2) gene polymorphisms. Differences in the allele and genotype frequencies between control and test groups were assessed by chi(2) test or by Monte Carlo simulations (P<0.05). Haplotype frequencies, linkage disequilibrium and Hardy-Weinberg equilibrium were also estimated.

RESULTS

No statistically significant differences were found in the genotype distribution or allelic frequencies of the polymorphisms. No differences were observed between control and test groups when different interleukin-1 gene cluster haplotypes were compared. Nevertheless, the interleukin-1A (-889) and interleukin-1B (+3953) polymorphic sites were in strong linkage disequilibrium (P=0.00014 for control group and P=0.0238 for the test group).

CONCLUSION

This study suggests that polymorphisms in the interleukin-1 gene cluster are not associated with early implant failure in a non-smoking Brazilian population.

Nutritional genomics in practice: where do we begin?

Nutritional genomics, which studies the genome-wide influences of nutrition, has far-reaching potential in the prevention of diet-related disease. It is highly likely that during the next decade the nutritional supplement and functional food industries will continue robust growth in response to advances in nutritional genomics research and its applications. Parallel to this growth will be impressive progress in understanding the specific influence of certain food components on metabolic pathways and on long-term risk for disease. As genetic information about individuals becomes available, such data are likely to redefine the current concept of preventive medicine. Dietetics professionals have the potential to harness this information and influence health promotion and disease prevention on a global scale. For these reasons, the dietetics profession has an exciting opportunity that, if seized and properly executed, could enhance the scientific foundation of clinical practice, improve therapeutic outcomes, and significantly expand career and economic opportunities for practitioners. The future of dietetics is unquestionably intertwined with nutritional genomics.

Association of the -159 CD14 gene polymorphism and lack of association of the -308 TNFA and Q551R IL-4RA polymorphisms with severe chronic periodontitis in Swedish Caucasians

BACKGROUND

Severe forms of periodontitis are suggested to have a genetic basis.

OBJECTIVE

The aim of the present investigation was to study the association of gene polymorphisms related to some immune regulation components (G-308A TNFA, Q551R IL-4RA and C-159T CD14) with severe chronic periodontitis.

MATERIALS AND METHODS

Sixty patients (aged 36-74 years; mean 54.5+/-8.5) with severe and generalized chronic periodontitis were included. The patients exhibited bone loss >50% at all teeth. Thirty-nine periodontally healthy subjects between 35 and 78 years of age (mean 51.0+/-10.9) were recruited as controls. DNA was isolated from peripheral blood cells and genotyping was performed by combination of PCR and restriction endonuclease mapping.

RESULTS

While gene polymorphisms for TNFA and IL-4RA did not show any association with severe chronic periodontitis, the analysis of the -159 CD14 gene polymorphism revealed significant differences between test and control groups. The proportion of subjects that exhibited the TT genotype was significantly smaller in the group with severe periodontitis than in periodontal healthy group (p=0.028; Fisher's exact test). The C allele carriage was 90% in the periodontitis group and significantly higher than in the healthy control group (72%).

CONCLUSION

It is suggested that the -159 CD14 gene polymorphism is associated with chronic periodontitis in Caucasian subjects of a north European origin.

Prediction of malignant potential in reflux disease: are cytokine polymorphisms important?

OBJECTIVES

Esophageal reflux is common in the Western world and can lead to a number of diseases, such as esophagitis, Barrett's esophagus, and adenocarcinoma. Barrett's predisposes to adenocarcinoma and endoscopic surveillance may lead to earlier detection of adenocarcinoma. However, clinical methods only identify one patient in 15 with Barrett's esophagus. The aim of this study was to find factors that may help identify patients with Barrett's earlier.

METHODS

Blood samples and detailed histories were taken from 456 patients with gastroesophageal reflux who were recruited into three study groups: esophagitis, Barrett's esophagus without dysplasia, and Barrett's with dysplasia or adenocarcinoma. PCR was used to determine the frequency of five functional cytokine polymorphisms: interleukin-1 receptor antagonist position +2018 (IL-1 Ra +2018), interleukin-1 beta position -511 (IL-1 beta-511), tumor necrosis factor-alpha position -238 (TNF-alpha-238), interleukin-10 position +1082 (IL-10 +1082), and interleukin-4 receptor position -1902 (IL-4R -1902).

RESULTS

IL-1 Ra +2018 genotype 2/2 was associated with Barrett's more commonly than esophagitis (OR-3.7, p= 0.0345). The IL-10 +1082 genotype 2/2 was more strongly associated with Barrett's and adenocarcinoma than esophagitis (OR-1.76, p= 0.056 and OR 1.96, p= 0.025, respectively). There were no differences for the IL-1 beta-511, IL-4R -1902, and TNF-alpha-238 polymorphisms.

CONCLUSIONS

Cytokine polymorphisms are more commonly found in patients with Barrett's or adenocarcinoma than those with esophagitis. Together with demographic data, this may help identify those patients with Barrett's who would benefit from surveillance.

Association of interleukin-1 polymorphisms with aggressive periodontitis

BACKGROUND

Genetic polymorphisms for interleukin (IL)-1alpha and -1beta have been proposed as potential genetic markers for periodontal diseases. Since the prevalence of these polymorphisms could be race-related, and no data exist about the frequency of these polymorphisms in the Chilean population, the aim of the current study was to investigate the association of the interleukin-1 gene polymorphisms with aggressive periodontitis (AgP).

METHODS

Thirty-six patients with AgP, 75 healthy controls, and 75 subjects of unknown periodontal status (reference population) were genotyped for the IL-1A -889 and IL-1B +3954 loci, by polymerase chain reaction (PCR) amplification followed by restriction enzyme digestion and gel electrophoresis. Data were analyzed using the chi-square test, calculating odds ratios (OR) and confidence intervals (CI).

RESULTS

The prevalence of the positive composite IL-1 genotype was higher in patients (25%) than in healthy controls (12%), but the difference was not significant (P= 0.14). The IL-1B +3954 homozygous for allele 1 frequency was higher in controls than in patients suggesting a protective factor for AgP. The heterozygous for allele 2 of the IL- 1B showed a significant association with AgP (OR = 2.86, 95% CI 1.06 to 7.71, P= 0.030). No association was observed in localized AgP and generalized AgP between the extent of disease and the presence of the composite positive genotype. Because the number of smokers was too small in patients and in controls, no other analyses were performed.

CONCLUSION

The results of the present study support a positive association between AgP and the presence of the IL-1B +3954 allele 2 polymorphism.

Association analysis between interleukin-1 family polymorphisms and generalized aggressive periodontitis in a Chinese population

BACKGROUND

It has been suggested that aggressive periodontitis (AgP) has a genetic basis, but this theory has not been confirmed. The intent of this investigation was to study whether specific interleukin (IL)-1 genotypes and/or alleles could be used to predict susceptibility to generalized AgP (GAgP) in Chinese.

METHODS

The GAgP group consisted of 122 patients, and the control group included 95 healthy subjects. Single nucleotide polymorphisms at IL-1A (+4845) and IL-1B (-511, +3954) were analyzed by standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The polymorphism of a variable number tandem repeat (VNTR) in intron 2 of IL-1RN was detected by PCR amplification and fragment size analysis.

RESULTS

There was no significant association of IL-1 polymorphisms with GAgP in the unstratified subjects. However, when cases were stratified by gender, the frequencies of A2+ genotype and allele 2 at IL-1A +4845 were significantly increased in male patients compared to male controls (genotype: odds ratio [OR] 5.58, 95% confidence interval [CI]: 1.09 to 28.68, P = 0.039; allele: OR 4.97, 95% CI: 1.01 to 24.50, P = 0.049; adjusted for age and smoking status). The frequency of IL-1B -511 A1/A2 heterozygote was significantly increased in male GAgP group compared to male controls (adjusted OR 3.16, 95% CI: 1.01 to 9.89, P = 0.048). In females, no significant differences were found between patients and controls in corresponding analyses at all polymorphic loci. A possible combined effect of IL-1B -511 polymorphism and smoking on the elevated risk to GAgP was observed. The OR of GAgP for combined A2+ genotype and smoking was 12.45 (95% CI: 1.43 to 108.06, P = 0.022), and for combined allele 2 and smoking was 18.25 (95% CI: 2.32 to 143.86, P = 0.006).

CONCLUSIONS

The polymorphisms of IL-1A +4845 and IL-1B -511 may play an important role in determining GAgP susceptibility in Chinese males. Furthermore, a possible combined effect of the polymorphism of IL-1B -511 and smoking on GAgP susceptibility was suggested.

Oral mucosal endotoxin tolerance induction in chronic periodontitis

The oral mucosa is exposed to a high density and diversity of gram-positive and gram-negative bacteria, but very little is known about how immune homeostasis is maintained in this environment, particularly in the inflammatory disease chronic periodontitis (CP). The cells of the innate immune response recognize bacterial structures via the Toll-like receptors (TLR). This activates intracellular signaling and transcription of proteins essential for the induction of an adaptive immune response; however, if unregulated, it can lead to destructive inflammatory responses. Using single-immunoenzyme labeling, we show that the human oral mucosa (gingiva) is infiltrated by large numbers of TLR2(+) and TLR4(+) cells and that their numbers increase significantly in CP, relative to health (P < 0.05, Student's t test). We also show that the numbers of TLR2(+) but not TLR4(+) cells increase linearly with inflammation (r(2) = 0.33, P < 0.05). Double-immunofluorescence analysis confirms that TLR2 is coexpressed by monocytes (MC)/macrophages (mphi) in situ. Further analysis of gingival tissues by quantitative real-time PCR, however, indicates that despite a threefold increase in the expression of interleukin-1beta (IL-1beta) mRNA during CP, there is significant (30-fold) downregulation of TLR2 mRNA (P < 0.05, Student's t test). Also showing similar trends are the levels of TLR4 (ninefold reduction), TLR5 (twofold reduction), and MD-2 (sevenfold reduction) mRNA in CP patients compared to healthy persons, while the level of CD14 was unchanged. In vitro studies with human MC indicate that MC respond to an initial stimulus of lipopolysaccharide (LPS) from Porphyromonas gingivalis (PgLPS) or Escherichia coli (EcLPS) by upregulation of TLR2 and TLR4 mRNA and protein; moreover, IL-1beta mRNA is induced and tumor necrosis factor alpha (TNF-alpha), IL-10, IL-6, and IL-8 proteins are secreted. However, restimulation of MC with either PgLPS or EcLPS downregulates TLR2 and TLR4 mRNA and protein and IL-1beta mRNA and induces a ca. 10-fold reduction in TNF-alpha secretion, suggesting the induction of endotoxin tolerance by either LPS. Less susceptible to tolerance than TNF-alpha were IL-6, IL-10, and IL-8. These studies suggest that certain components of the innate oral mucosal immune response, most notably TLRs and inflammatory cytokines, may become tolerized during sustained exposure to bacterial structures such as LPS and that this may be one mechanism used in the oral mucosa to attempt to regulate local immune responses.

Analysis of the MMP-9 (C-1562 T) and TIMP-2 (G-418C) gene promoter polymorphisms in patients with chronic periodontitis

BACKGROUND

Matrix metalloproteinases (MMP)-9 is an important member of the matrix metalloproteinase family. A functional polymorphism has been described in the promoter region of the human MMP-9 gene. A C-to-T base exchange at -1562 creates two different alleles, and the C/T and T/T genotypes promote high activity of the MMP-9 gene promoter, increasing the risk for inflammatory diseases. The metalloproteinase-2 tissue inhibitor (TIMP-2) regulates the activity of MMPs in the extracellular matrix, and a polymorphism at the -418 position of the TIMP-2 gene promoter has been found in a Sp-1 binding site. In this study we have investigated the association between the above-mentioned polymorphisms and chronic periodontitis severity.

METHODS

Genomic DNA from oral mucosa of 100 subjects was amplified by polymerase chain reaction and analysed by restriction endonuclease digestion. The significance of the differences in observed frequencies of polymorphisms in moderate and severe disease and healthy groups was assessed by chi(2) test (p<0.05).

RESULTS

No association was observed between the polymorphism in the promoter region of MMP-9 (p=0.6693) and chronic periodontitis. The analysis of TIMP-2 showed that the G/G genotype was found at a frequency of 99%.

CONCLUSION

The results show that the polymorphism in the promoter region of MMP-9 gene is not associated with chronic periodontitis. The high frequency of GG genotype in the TIMP-2 gene promoter in the population studied did not allow any conclusion regarding its effect on chronic periodontitis.

Association of Interleukin-1 Polymorphisms With Periodontal Disease

BACKGROUND

Several studies have investigated genetic polymorphisms for cytokines as potential genetic markers for periodontitis. Some studies have found that interleukin (IL)-1A and IL-1B polymorphisms are associated with a higher severity of periodontitis, while others found no association. The aims of this study were to determine the prevalence of the IL-1A-889 and IL-1B+3954 (previously described as +3953) polymorphisms in Chileans and their association with periodontitis.

METHODS

Subjects aged 20 to 48 were selected from people requesting dental treatment at a public health center in Santiago, Chile. A case-control study of 330 cases of periodontitis patients and 101 healthy controls was performed. A full-mouth periodontal examination was performed on each subject and a structured questionnaire was conducted to determine smoking habits. Cases were categorized as having initial, moderate, or severe periodontitis according to the percentage of sites with clinical attachment loss > or =3 mm. Genomic DNA was analyzed for polymorphism in the IL-1A gene at site -889 and IL-1B gene at site +3954 by polymerase chain reaction (PCR) amplification followed by restriction enzyme digestion and gel electrophoresis. Data were analyzed by chi square test, analysis of variance (ANOVA), and by calculating odds ratio (OR) and 95% confidence intervals (CI).

RESULTS

Demographic and socio-economic characteristics of subjects were similar in cases and in controls. A higher frequency of heterozygous of the IL-1A-889 was found in cases than in controls, but the difference was not significant. The heterozygous of the IL-1B+3954 was significantly higher in cases than in controls and was associated with periodontitis (OR 3.12, 95% CI 1.59 to 6.09, P = 0.001). The homozygous for allele 1 of the IL-1B+3954 was a protective factor for periodontitis (OR 0.35, 95% CI 0.19 to 0.66, P = 0.001). The prevalence of positive genotype (at least one allele 2 present at each locus) was significantly higher in cases (26.06%) than in controls (9.9%) and was significantly associated with periodontitis (OR 3.21, 95% CI 1.60 to 6.44, P = 0.001), irrespective of the smoking status and periodontitis severity. Sensitivity of positive genotype was 26%, the specificity 90%, and the positive predictive value 89%.

CONCLUSION

Within the limits of this study, the results show that individuals carrying the positive genotype have significantly greater risk for developing periodontitis.

Interleukin-1 beta gene polymorphism related with allergic pathogenesis in Iris constitution

Iridological constitution has a strong familial aggregation and is implicated in heredity. The aetiology of inflammatory bowel disease is still unknown. However, from genetic epidemiological studies there is considerable evidence that genetic factors are associated with both Crohn's disease and ulcerative colitis. We investigated the relationships between Iridological constitution and interleukin 1 beta (IL-1beta) gene polymorphism. IL-1beta is a major proinflammatiry cytokine, and the polymorphisms of this gene have been shown to be of importance in a number of diseases. Especially, IL-1 has been suspected of involvement in allergic pathogenesis. Also, IL-1beta genotype is one of the genetic markers of gastric cancer. Therefore, we classified 166 individuals according to Iris constitution, and determined IL-1beta genotype. The frequencies of Iris constitutions as follows: neurogenic type, 41 (24.7%); abdominal connective tissue weakness type, 53 (31.9%); cardio-renal connective tissue weakness type, 50 (30.1%); the others type, 22 (13.3%). Especially, the frequency of abdominal connective tissue weakness type was higher in C/T genotype than in the remaining constitutions although the statistical power was very weak. Furthermore, we first attempted to explore possible involvement of the IL-1beta polymorphism and the Iris constitution.

A Pilot Study Into Measurements of Markers of Atherosclerosis in Periodontitis

BACKGROUND

Periodontitis may be a possible risk factor for atherosclerosis. The current pilot study explored arterial wall thickness and other variables associated with atherosclerosis in healthy subjects with and without periodontitis.

METHODS

Patients with moderate (N = 34) and severe periodontitis (N = 15) and controls (N = 14) were recruited. Intima media thickness (IMT) of the common carotid arteries (CCA), internal carotid arteries (ICA), and bifurcations of carotid arteries (BCA) was estimated bilaterally using B-mode ultrasound. An overall IMT was calculated as the mean of these six measurements. C reactive protein (CRP), fibrinogen, and von Willebrand factor (vWf) were measured in plasma as indicators of systemic inflammation and atherosclerotic disease. Microalbuminuria was determined as a marker of endothelial cell dysfunction.

RESULTS

IMT for CCA were 0.64, 0.68, and 0.69 mm for control, moderate, and severe periodontitis, respectively (not significant). IMT for BCA did not vary among groups. IMT of ICA was largest for severe periodontitis (0.81 mm); corresponding values for controls and moderate periodontitis were 0.58 and 0.55 mm, respectively (P= 0.023). Severe periodontitis patients had an overall IMT of 0.76 mm, while moderate periodontitis patients and controls had lower values (0.64 and 0.65 mm, respectively; P= 0.153). After adjusting for potential confounding factors, the increased IMT for ICA in severe periodontitis was also significant (Padj = 0.040). CRP (P= 0.020, Padj = 0.050) and vWf (P= 0.019, Padj = 0.013) were higher in periodontitis than controls; microalbuminuria was not different between groups. Power calculations suggest that a 4-fold expansion of the severe patient and control groups will result in a high chance (power level 80%) that a clinically significant association between the overall IMT and periodontitis will be observed.

CONCLUSION

The present pilot study indicates that a full study investigating the relationship between periodontitis and atherosclerosis is warranted.

Mechanisms of action of environmental factors--tobacco smoking

AIM

To review the potential biological mechanisms underlying the effects of tobacco smoking on periodontitis.

MAIN FINDINGS

Smoking has major effects on the host response, but there are also a number of studies that show some microbiological differences between smokers and non-smokers. Smoking has a long-term chronic effect on many important aspects of the inflammatory and immune responses. Histological studies have shown alterations in the vasculature of the periodontal tissues in smokers. Smoking induces a significant systemic neutrophilia, but neutrophil transmigration across the periodontal microvasculature is impeded. The suppression of neutrophil cell spreading, chemokinesis, chemotaxis and phagocytosis have been described. Protease release from neutrophils may be an important mechanism in tissue destruction. Tobacco smoke has been found to affect both cell-mediated immunity and humoral immunity. Research on gingival crevicular fluid has demonstrated that there are lower levels of cytokines, enzymes and possibly polymorphonuclear cells in smokers. In vitro studies have shown detrimental effects of nicotine and some other tobacco compounds on fibroblast function, including fibroblast proliferation, adhesion to root surfaces and cytotoxicity.

CONCLUSION

Tobacco smoking has widespread systemic effects, many of which may provide mechanisms for the increased susceptibility to periodontitis and the poorer response to treatment.

Reconstitution of a Hyperinflammatory Prostaglandin E2Response toPorphyromonas gingivalisChallenge in Severe Combined Immunodeficient Mice

BACKGROUND

The purpose of this study was to determine whether lymphocytic cells regulate the monocytic hyperinflammatory trait (MO+) in chronic periodontitis patients. Using a P. gingivalis challenge model in severe combined immunodeficient (SCID) mice, we tested the effects of adoptively transferred human peripheral blood leukocytes from gingivitis and chronic periodontitis diabetic and non-diabetic individuals on monocytic responses.

METHODS

This response was examined using the subcutaneous tissue chamber infection model. Three weeks following cell reconstitution, all SCID mice were challenged with 10(9) colony forming units of live P. gingivalis HG405. Chamber contents were collected at day 7 after bacterial challenge for prostaglandin E2 (PGE2) analysis and chamber rejection monitored up to day 30. Gingival crevicular fluid (GCF) samples were collected from all patients for PGE2 analysis. Both chamber fluid- and GCF-PGE2 levels were determined by enzyme-linked immunosorbent assays (ELISA).

RESULTS

Significantly elevated GCF-PGE2 levels were found in diabetic as well as in non-diabetic patients with moderate/advanced periodontitis compared to diabetic and non-diabetic subjects with gingivitis/mild periodontitis at P= 0.01 and P= 0.001, respectively. As reflected in chamber fluid PGE2 levels and percentage chamber rejection, lymphocytic sensitization to P. gingivalis occurred in both diabetics and non-diabetics with moderate/advanced periodontitis, but not in diabetics and non-diabetics with gingivitis/mild periodontitis.

CONCLUSIONS

These results suggest that the exaggerated monocytic inflammatory response trait (MO+) associated with moderate/advanced chronic periodontitis is due, at least in part, to lymphocytic modulation, while the directional findings for lymphocytes from diabetic subjects deserve further investigation. Our findings further demonstrate that the SCID mouse model is a useful animal model to study human immune responses to periodontal microorganisms.

Clinical Consequences of IL-1 Genotype on Early Implant Failures in Patients under Periodontal Maintenance

BACKGROUND

Implant failure and biologic complications such as periimplantitis are not completely avoidable. Are there any genetic and microbiologic parameters that could be used to identify patients at risk for implant failure, preferably prior to treatment? This would result in improvement of the diagnostics, treatment decision, and risk assessment.

PURPOSE

The aims of this retrospective study were to describe (1) the absolute failure rate of Brånemark System implants (Nobel Biocare AB, Göteborg, Sweden) consecutively installed over a 10-year period in partially edentulous patients treated for periodontal disease prior to implant treatment and under regular professional maintenance, (2) the rate of interleukin-1 (IL-1) polymorphism in those patients who experienced at least one implant failure during the first year of function, and (3) the prevalence of periodontal pathogens in dental and periimplant sites with and without signs of inflammation.

MATERIAL AND METHODS

Of 766 patients, 81 encountered at least one implant failure; 22 patients were clinically examined and were tested genetically for IL-1 genotypes. The presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella nigrescens was analyzed.

RESULTS

The absolute implant survival rate for the whole population was 95.32%; 10.57% of the patients encountered an implant loss. Implant loss in the examined group (n = 22) was 32 of 106 (30.1%); 10 (45%) of the 22 patients were smokers, and 6 (27%) of the 22 patients were IL-1 genotype positive. Patients positive for IL-1 genotype were not more prone to implant loss; however, a significant synergistic effect with smoking was demonstrated. Between patients who were IL-1 genotype positive and those who were IL-1 genotype negative, the differences in regard to bleeding on probing or periodontal pathogens did not reach statistical significance.

CONCLUSION

The overall implant failure rate in a population treated and maintained for periodontal disease is similar to that of healthy subjects. A synergistic effect found between smoking and a positive IL-1 genotype resulted in a significantly higher implant loss. This indicates that further research with a larger patient group should focus on multifactorial analysis for adequate risk assessment.

Risk determinants of periodontal disease - an analysis of the Study of Health in Pomerania (SHIP 0)

BACKGROUND

In this study, risk determinants were determined for periodontal disease in the representative population sample (n=3146) of the Study of Health in Pomerania.

METHODS

After examining the net random sample (response 69%) and exclusion of edentulous cases and those with missing values, 2595 subjects remained. Using a multivariate, fully adjusted logistic regression, different definitions of "periodontally diseased/healthy" were examined as the dependent variable (extent of attachment loss (AL> or =4 mm, combined AL and tooth loss). The independent variables used were sociodemographic factors (age, gender, income, education), medical factors (systemic diseases, drugs), behavioral factors (regular dental checkup, smoking), and oral factors (presence of supragingival calculus and plaque).

RESULTS

The following risk determinants were found for AL: male gender, presence of supragingival plaque and calculus, smoking, low educational level. For the combination of AL and tooth loss, risk determinants were female gender, supragingival plaque, smoking, and low educational level. Consumption of antiallergic medications and regular dental checkups proved to be protective. Smoking was the most influential risk determinant. These parameters explained approximately 43-55% of the variation.

CONCLUSION

These results concur with those of the literature. In order to explain disease status further, host-response and microbiological factors must also be examined.

Modulation of Clinical Expression of Plaque-Induced Gingivitis: Interleukin-1 Gene Cluster Polymorphisms

BACKGROUND

The purpose of the present study was to determine the association of interleukin-1 (IL-1) gene polymorphisms with clinical parameters of gingivitis in a large experimental gingivitis trial and with each of two subgroups, high responders (HR) and low responders (LR), with distinct susceptibility to gingivitis.

METHODS

Ninety-six systemically and periodontally healthy non-smokers, 46 males (mean age: 23.9+/-1.7) and 50 females (mean age: 23.3+/-1.6) were included in a randomized, split-mouth, localized 21-day experimental gingivitis trial. Plaque index (PI), gingival index (GI), gingival crevicular fluid volume (GCF), and angulated bleeding score (AngBS) were recorded. Two subgroups were defined from the total study population (HR, LR) characterized by substantially different severity of gingival inflammation despite similar plaque accumulation rate. The study population was typed for interleukin-1 alpha (IL-1A+4845), interleukin-1 beta (IL-1B+3953, IL-1B-511), and IL-1 receptor antagonist (IL-1RN, intron 2 variable number tandem repeats) gene polymorphisms. Gene variants were analyzed by amplifying the polymorphic region using polymerase chain reaction, followed by restriction-enzyme digestion and agarose gel electrophoresis.

RESULTS

Neither IL-1A+4845, IL-1B+3953, or the combined (IL-1A+4845 x 2 - IL-1B+3953 x 2) genotype was associated with clinical parameters in the overall population. IL-1RN was significantly associated with test quadrant PI (P= 0.046), GCF (P= 0.05), and GI (P= 0.018). The genotype distribution in HR and LR subjects was significantly different for IL-1RN (P= 0.045) and for IL-1B-511 (P= 0.023).

CONCLUSION

The results of the present study suggest an association between IL-1RN polymorphism and subject-based clinical behavior of the gingiva in response to de novo plaque accumulation, as well as a possible association between IL-1B-511 polymorphism and gingivitis susceptibility.

Polymorphisms of the Interleukin-1β Gene Affect the Risk of Myocardial Infarction and Ischemic Stroke at Young Age and the Response of Mononuclear Cells to Stimulation In Vitro

Objectives— To investigate the role of interleukin-1β (IL-1β) gene polymorphisms as a link between inflammation, coagulation, and risk of ischemic vascular disease at young age.

Methods and Results— A total of 406 patients with myocardial infarction (MI) at young age, frequency-matched for age, sex, and recruitment center, with 419 healthy population-based controls and 134 patients with ischemic stroke at young age, matched by age and sex, with 134 healthy population-based controls, were studied. Subjects carrying the TT genotype of the −511C/T IL-1β polymorphism showed a decreased risk of MI (odds ratio [OR], 0.36; 95% CI, 0.20 to 0.64) and stroke (OR, 0.32; 95% CI, 0.13 to 0.81) after adjustment for conventional risk factors. In both studies, the T allele showed a codominant effect ( P =0.0020 in MI; P =0.021 in stroke). Mononuclear cells from volunteers carrying the T allele showed a decreased release of IL-1β and a decreased expression of tissue factor after stimulation with lipopolysaccharide compared with CC homozygotes. The presence of a monoclonal antibody against IL-1β during cell stimulation resulted in a marked reduction of tissue factor activity expression.

Conclusions— -511C/T IL-1β gene polymorphism affects the risk of MI and ischemic stroke at young age and the response of mononuclear cells to inflammatory stimulation.

Effect of periodontal therapy on crevicular fluid interleukin-1beta and interleukin-10 levels in chronic periodontitis

OBJECTIVES

This study aimed to analyse the levels of the proinflammatory cytokine IL-1beta and the anti-inflammatory cytokine IL-10 in gingival crevicular fluid (GCF) of patients with chronic periodontitis prior to, and following, periodontal therapy for a period of 32 weeks.

MATERIAL AND METHODS

GCF samples were obtained from 24 non-diseased and 72 diseased sites of 12 periodontal patients prior to as well as at 6, 16 and 32 weeks post-periodontal therapy. All sites received conventional periodontal treatment and IL-1beta and IL-10 levels (concentration and total amount) were determined by enzyme linked immunosorbent assay (ELISA). Additionally, probing pocket depth (PD), clinical attachment loss (CAL), gingival (GI) and plaque (PII) indices were evaluated pre-and post-therapy.

RESULTS

IL-1beta was detected in 382 out of 384 samples, while IL-10 was detected in 337 out of 384 samples. The total amount of IL-1beta was significantly higher at diseased compared to non-diseased sites (p<0.01). Following therapy, IL-1beta total amounts were reduced, while IL-1beta concentration gradually increased. IL-10 total amounts (per 30 s sample) were similar in diseased and non-diseased sites, and following therapy they remained almost unchanged. By contrast, IL-10 concentration was significantly higher in non-diseased sites (p<0.01) and displayed a significant increase post-therapy. Moreover, IL-1beta concentration and total amount were significantly greater in smokers following therapy, while IL-10 total amount was significantly higher in non-smokers both prior to and following therapy. Total IL-1beta amounts were positively correlated with GI and Pll. A weak negative correlation between IL-1beta and IL-10 levels was noted (p<0.05).

CONCLUSIONS

The data suggest that the total amount rather than the concentration of IL-1beta in GCF seemed to be closely associated with periodontal disease severity. Moreover, smoking status influenced IL-1beta and IL-10 levels. An inverse relationship between IL-1beta and IL-10 was evident.

A review of selected dental literature on evidence-based treatment planning for dental implants: Report of the Committee on Research in Fixed Prosthodontics of the Academy of Fixed Prosthodontics

This literature review summarizes research with the aim of providing dentists with evidence-based guidelines to apply when planning treatment with osseointegrated implants. Peer-reviewed literature published in the English language between 1969 and 2003 was reviewed using Medline and hand searches. Topics reviewed include systemic host factors such as age, gender, various medical conditions, and patient habits, local host factors involving the quantity and quality of bone and soft tissue, presence of present or past infection and occlusion, prosthetic design factors, including the number and arrangement of implants, size and coatings of implants, cantilevers and connections to natural teeth, and methods to improve outcomes of implant treatment in each category. The review demonstrated that there is no systemic factor or habit that is an absolute contraindication to the placement of osseointegrated implants in the adult patient, although cessation of smoking can improve outcome significantly. The most important local patient factor for successful treatment is the quality and quantity of bone available at the implant site. Specific design criteria are provided, including guidelines for spacing of implants, size, materials, occlusion, and fit. Limitations in the current body of knowledge are identified, and directions for future research are suggested.

Association between the interleukin-1beta C(-511)T polymorphism and blood pressure in a Chinese hypertensive population

The interleukin-1beta (IL-1beta) is an important pro-inflammatory cytokine in a broad spectrum of physiological processes. Previous investigations have observed that levels of the IL-1beta were higher in essential hypertensive patients and the IL-1beta gene polymorphism has been shown to be related to IL-1 production. We hypothesized that genetically determined differences in activity or responsiveness of cytokine(s) might contribute to hypertension. In this report, we utilized a family-based design to test the association between the IL-1beta C(-511)T polymorphism and blood pressure levels in hypertensive patients chosen from rural communities in Anhui, China. In men, carriers of the IL-1beta (-511)*C allele were found to have lower systolic (P = 0.049) blood pressure levels compared with T homozygotes, which conforms to an additive effect model. By contrast, no significant association between the IL-1beta gene and blood pressure levels was revealed in women. Our results suggested a significant role of the IL-1beta C(-511)T polymorphism in the control of blood pressure in Chinese hypertensives.

Polymorphisms in the vitamin D receptor gene are associated with periodontal disease

BACKGROUND

Genetic polymorphisms in the vitamin D receptor (VDR) gene are associated with bone homeostasis and diseases in which bone loss is a cardinal sign. The aim of this study was to determine whether chronic periodontal disease in a Brazilian population is associated with polymorphisms in the VDR gene.

METHODS

Clinical examination and recordings of probing depth and clinical attachment level were performed in 113 unrelated adults who were divided into two groups: 44 healthy individuals (control group) and 69 subjects with chronic periodontitis (CP). DNA was obtained from the subjects' epithelial cells by scraping the buccal mucosa. Two polymorphisms in the VDR gene were analyzed by polymerase chain reaction, followed by Taql and BsmI restriction endonuclease digestion.

RESULTS

Frequencies of VDR/TaqI and VDR/BsmI showed significant differences between the control group and the CP group (P < 0.05). The "Tb" haplotype was prevalent in the control group (43.2%), and the "TB" haplotype in the CP group (36.6%). The "TB" haplotype seemed to increase susceptibility to periodontal disease (odds ratio [OR] = 2.19). The heterozygous haplotype "TB/tb" was predominant in the CP group (OR = 4.32; P = 0.005).

CONCLUSIONS

TaqI and BsmI polymorphisms of the VDR gene are associated with clinical attachment loss due to periodontal disease in a Brazilian population. These findings suggest that VDR genotype might be a risk indicator for susceptibility to chronic periodontitis.

Periodontal diseases and the risk of coronary heart and cerebrovascular diseases: a meta-analysis

BACKGROUND

This meta-analysis was conducted to examine the relationship between periodontal diseases and coronary heart diseases (CHD) and cerebrovascular diseases (CVD) in observational studies.

METHODS

This study was based on seven cohort studies and four studies of other designs that met prestated inclusion criteria. Information on study design, year of publication, study location, sample size, study population, participant characteristics, measurement of risk factors, exposure and outcome measures, matching, controlling for confounders, and risk estimates was abstracted independently by two investigators using a standard protocol.

RESULTS

Subjects with periodontitis had an overall adjusted risk of CHD that was 1.15 times (95% confidence interval [CI]: 1.06 to 1.25; P = 0.001) the risk for healthy subjects. There was no heterogeneity among the studies in the overall relative risk estimate (P = 0.472). As compared to healthy subjects, those with periodontitis had an overall adjusted relative risk of CVD of 1.13 (95% CI: 1.01 to 1.27; P = 0.032).

CONCLUSIONS

Findings indicated that periodontal infection increases the risk of CHD and CVD. However, this meta-analysis provided no evidence for the existence of strong associations between periodontitis and CHD and CVD. Larger and better-controlled studies involving socially homogeneous populations and measuring specific periodontal pathogens are required to identify a definite association between periodontal disease and the risk of coronary heart disease and cerebrovascular disease.

CARD15 gene mutations in periodontitis

OBJECTIVES

The CARD15 gene encodes the Nod2 protein, which is involved in intracellular recognition of bacterial products like peptidoglycan, activates inflammation and regulates apoptosis through nuclear factor-kappa B, a transcription factor that plays a central role in the innate immunity. Two functional mutations, an insertion mutation at nucleotide 3020 (3020insC) and a missense mutation C2104T in the CARD15 gene (originally NOD2 gene) have been reported to be associated with Crohn's disease. Our aim was to investigate the occurrence of CARD15 gene polymorphisms in adult patients with periodontitis taking into account smoking and presence of putative periodontal pathogens as additional variables.

MATERIAL AND METHODS

A case-control study was performed in 104 Dutch Caucasian patients with severe adult periodontitis (54 non-smokers and 50 smokers, mean age 46 years) and in 97 ethnically matched, periodontal healthy controls (73 non-smokers and 24 smokers, mean age 40 years). DNA isolated from a mouthwash was typed with PCR technology. Presence of putative periodontal pathogens was established by culture technique.

RESULTS

Frequencies of the CARD15 3020insC and 2104T mutations were similar in the periodontitis group and in the control group (5.1% and 13.3%; 5.2% and 10.3%, respectively). The highest carrier frequency of CARD15 mutations was found in non-smoking patients without Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans (29.4% versus 17.4% in controls); however it did not reach statistical significance.

CONCLUSION

Our results suggest no role for CARD15 3020insC and C2104T mutations in adult periodontitis.

Effect of the Interleukin-1 Genotype on Outcomes of Regenerative Periodontal Therapy With Bone Replacement Grafts

BACKGROUND

Previous studies have shown an association between a specific genotype for the inflammatory cytokine interleukin (IL)-1 and the severity of periodontal disease. The purpose of this study was to evaluate the effect of the IL-1 genotype on the outcomes of periodontal surgical regenerative treatment with bone replacement grafts.

METHODS

Forty-four patients with interproximal intrabony defects were treated with bone replacement grafts. Probing depths (PD) and clinical attachment levels (CAL) were measured before treatment and at least 9 months post-treatment. Whole-mouth plaque index (WMPI) and bleeding index (WMBI) were recorded as well. All patients were tested for the IL-1 genotype.

RESULTS

Thirteen (29.55%) of the patients were IL-1 genotype positive. There was no statistically significant difference between the genotype-positive and genotype-negative groups regarding age, smoking status, gender, WMPI, and WMBI. There was no significant difference in PD or CAL between the genotype-positive and genotype-negative groups at baseline. Genotype-positive patients had a smaller reduction in probing depth (1.86 mm versus 2.13 mm) and a greater gain of clinical attachment (1.20 mm versus 0.65 mm). These differences were not statistically significant (P = 0.70, P = 0.40). Multivariate regression analysis showed that presurgical PD significantly influenced post-surgical PD and CAL, and only WMPI significantly influenced CAL.

CONCLUSION

In this study, there was no evidence that the IL-1 genotype influences the clinical treatment outcomes of regenerative periodontal therapy with bone replacement grafts.

Interleukin-1 Receptor Signaling Mediates Atherosclerosis Associated With Bacterial Exposure and/or a High-Fat Diet in a Murine Apolipoprotein E Heterozygote Model

BACKGROUND

Current data demonstrate that progressive atherosclerosis is associated with activation of the inflammatory process, as evidenced by systemic elevations of molecules such as tumor necrosis factor, interleukin (IL)-6, and IL-1. It has been postulated that inflammatory events within an atherogenic lesion are induced by oxidized LDL. Recent evidence suggests that infectious agents, including those that cause periodontal disease, may also play an important role. Studies presented here tested the hypothesis that IL-1 receptor (IL-1R1) signaling plays a crucial role in bacteria- and/or high-fat diet (HFD)-enhanced atherogenesis.

METHODS AND RESULTS

Ten-week-old ApoE+/- mice lacking either 1 IL-1R1 allele (ApoE+/-/IL-1R1+/-) or 2 IL-1R1 alleles (ApoE+/-/IL-1R1-/-) fed either an HFD or regular chow were inoculated intravenously with live Porphyromonas gingivalis (P gingivalis) (10(7) CFU), an important periodontal pathogen, or vehicle once per week for 14 or 24 consecutive weeks. Histomorphometry of plaque cross-sectional area in the proximal aortas, en face measurement of plaque area over the aortic trees, and ELISA for systemic proinflammatory mediators were performed. Atherosclerotic lesions of proximal aortas and aortic tree were substantially reduced in ApoE+/-/IL-1R1-/- mice than in ApoE+/-/IL-1R1+/- mice challenged with P gingivalis. At 24 weeks after P gingivalis inoculation, proximal aortic lesion size quantified by histomorphometry was 5-fold-reduced in chow-fed ApoE+/-/IL-1R1-/- mice than in ApoE+/-/IL-1R1+/- mice (P<0.05). In the HFD group, ApoE+/-/IL-1R1-/- mice exhibited marked attenuation of the progression of atherosclerotic lesions (78% to 97%), with and without P gingivalis inoculation (P<0.05).

CONCLUSIONS

Ablation of IL-1R1 under P gingivalis challenge and/or an HFD reduced the progression of atherosclerotic plaques. These results indicate that IL-1 plays a crucial role in bacteria- and/or HFD-enhanced atherogenesis.

Cis-acting effect of the IL1B C−31T polymorphism on IL-1β mRNA expression

Since the effect of IL1B polymorphisms on IL-1beta production is still controversial, we selected two polymorphisms to test their cis-acting effect on IL-1beta mRNA expression by means of the allele-specific transcript quantification and the haplotype analysis. As for the C-31T polymorphism, we found that expression of the -31T allele was 2.2 times of the -31C allele. This higher transcription efficiency may correspond to the fact that C-31T is located in a TATA box. The other polymorphism, C+3954T, did not alter the levels of transcription. The use of the allele-specific transcript quantification enables us to exclude trans-acting effects of polymorphisms on the gene expression and contributes to understanding the roles of the IL1B polymorphisms in susceptibility to multifactorial diseases.

Matrix metalloproteinase-1 and -3 gene promoter polymorphisms in Japanese patients with periodontitis

BACKGROUND/AIMS

Matrix metalloproteinase (MMP)-1 and MMP-3 have important roles in the connective tissue remodelling and destruction processes in periodontitis. MMP-1 1G/2G (-1607) and MMP-3 5A/6A (-1171) polymorphisms have been identified and appear to influence the transcription of the genes. The aim of this study was to investigate whether these gene promoter polymorphisms were associated with the susceptibility to periodontitis.

MATERIAL AND METHODS

Genomic DNA was obtained from 37 generalised aggressive, 205 slight-to-severe generalised chronic-periodontitis patients and 142 healthy subjects. All subjects were non-smoking Japanese. We genotyped by using TaqMan PCR assay. The statistics were analysed by chi2-test.

RESULTS

We found no significant differences in genotype distributions, allele frequencies, carriage rates and haplotype frequencies in the MMP-1 and the MMP-3 gene promoter polymorphisms among all groups. The distributions of MMP-1 and MMP-3 genotypes in our study were different from those of previously reported in Caucasians or Brazilians, but consistent with previously reported in Japanese.

CONCLUSION

Our data did not support the hypothesis that MMP-1 and/or MMP-3 gene promoter polymorphisms influenced the susceptibility to periodontitis in Japanese patients, indicating MMP-1 and MMP-3 expressions were regulated by complex processes such as cytokine network in periodontal disease rather than gene polymorphisms.

Periodontitis and systemic inflammation: control of the local infection is associated with a reduction in serum inflammatory markers

Severe periodontitis is associated with elevated inflammatory markers in otherwise healthy populations. However, the nature of this association has not been determined. Our aim was to assess whether the degree of response to periodontal therapy was associated with changes in serological markers of systemic inflammation. Ninety-four systemically healthy subjects with severe generalized periodontitis participated in a prospective six-month blind intervention trial. Periodontal parameters and inflammatory markers [C-reactive Protein (CRP) and Interleukin-6 (IL-6)] were evaluated prior to and 2 and 6 mos after delivery of standard non-surgical periodontal therapy. Six months after treatment, significant reductions in serum IL-6 (p < 0.001, median decrease 0.2 ng/L, 95% CI 0.1-0.4 ng/L) and CRP (p < 0.0001, median decrease 0.5 mg/L, 95% CI 0.4-0.7) were observed. Decreases in inflammatory markers were significant in subjects with above average clinical response to periodontal therapy after correction for possible confounders. Periodontitis may add to the systemic inflammatory burden of affected individuals.

Monocyte activation by Porphyromonas gingivalis LPS in aggressive periodontitis with the use of whole-blood cultures

In this study, we re-visited the issue of hyper-responsiveness of monocytes to bacterial lipopolysaccharide (LPS) in aggressive periodontitis patients. We used whole-blood cultures to compare monocyte activation by Porphyromonas gingivalis LPS between Thai subjects with generalized aggressive periodontitis and those without periodontitis. Upon stimulation with P. gingivalis LPS, expression of co-stimulatory molecules on monocytes and expression of CD69 on NK and gamma delta T-cells were analyzed by flow cytometry, and the production of interleukin-1 beta and prostaglandin E(2) was monitored by ELISA. LPS stimulation resulted in a dose-dependent up-regulation of CD40, CD80, and CD86 on monocytes, and up-regulation of CD69 on NK cells and gamma delta T-cells in both the periodontitis and non-periodontitis groups. The levels of activation markers and the mediator production after LPS stimulation were quite similar for both groups. In conclusion, we did not observe hyper-responsiveness of monocytes to P. gingivalis LPS challenge in Thai patients with aggressive periodontitis.

Cytokine gene single nucleotide polymorphisms and susceptibility to and prognosis in cutaneous malignant melanoma

Cutaneous malignant melanoma (CMM) is a potentially fatal malignancy in which exposure to UV light is the most important risk factor. Several lines of evidence suggest that CMM patients develop an immune response to their tumours, although, in most cases, anti-tumour immune responses are insufficient to abrogate tumour development. Polymorphism in genes regulating the immune response and cell growth may result in increased susceptibility to and/or poorer prognosis in certain individuals. In this study, we addressed whether single nucleotide polymorphisms (SNPs) associated with differential expression of selected pro- and anti-inflammatory cytokines and growth factors [interleukin (IL)-1beta-35 and -511, IL-2 -330, IL-4 -590, IL-6 -174, IL-8 -251, interferon (IFN)-gamma+874 and transforming growth factor (TGF)beta1 +915] or as markers of candidate cytokine genes (IL-12 +1188) are associated with susceptibility to or known prognostic indicators (e.g. initial tumour growth phase, Breslow thickness, mitotic count in vertical growth phase tumours, tumour regression) in CMM. One hundred and sixty-nine British caucasian CMM patients and 261 controls were included in the study and all SNPs were genotyped by ARMS-PCR. No SNP genotypes or alleles showed significant associations with CMM susceptibility and only the IL-1beta-511 TT genotype was associated with thinner invasive tumours at presentation, as assessed by Breslow thickness at the clinically significant cut-off point of 1.5 mm [occurring in 2/51 (3.9%) thicker vs. 14/78 (17.9%) thinner tumours (P = 0.03; relative risk = 0.29 (95% confidence interval 0.05-0.95)]. These findings suggest that - with the possible exception of IL-1beta- genetic variation associated with differential expression of the selected pro- and anti-inflammatory cytokines is unlikely to play a major role in susceptibility to and prognosis in CMM.

FcgammaRIIB gene polymorphisms in Japanese periodontitis patients

Human type II low-affinity receptor for immunoglobulin G (FcgammaRII) constitutes a clustered gene family consisting of FcgammaRIIA, IIB and IIC genes. FcgammaRIIB is unique in its ability to transmit inhibitory signals in B cells via immunoreceptor tyrosine-based inhibitory motif (ITIM). B-cell activation and subsequent elevated production of IgG are the immunopathological features of inflammatory disease such as periodontitis. To determine whether an association with periodontitis susceptibility exists, genetic polymorphisms of FcgammaRIIB were examined in Japanese patients with aggressive periodontitis (AGP) and chronic periodontitis (CP), and in the race-matched healthy controls (HCs). A significant difference was observed in the distribution of FcgammaRIIB-232I/T allele (exon 5) between the AGP and HC groups, with enrichment of the 232T in the AGP group (P=0.006). In addition, the FcgammaRIIB-nt 646-184A/G allele (intron 4) distribution was significantly different between the CP and HC groups, with enrichment of the nt 646-184A in the CP group (P=0.011). These results document the association of FcgammaRIIB gene polymorphisms with susceptibility to periodontitis in the Japanese.

Quantitative gene expression profiling implicates genes for susceptibility and resistance to alveolar bone loss

Periodontal disease is one of the most prevalent chronic inflammatory diseases. There is a genetic component to susceptibility and resistance to this disease. Using a mouse model, we investigated the progression of alveolar bone loss by gene expression profiling of susceptible and resistant mouse strains (BALB/cByJ and A/J, respectively). We employed a novel and sensitive quantitative real-time PCR method to compare basal RNA transcription of a 48-gene set in the gingiva and the spleen and the subsequent changes in gene expression due to Porphyromonas gingivalis oral infection. Basal expression of interleukin-1 beta (Il1b) and tumor necrosis factor alpha (Tnf) mRNA was higher in the gingiva of the susceptible BALB/cByJ mice than in the gingiva of resistant A/J mice. Gingival Il1b gene expression increased further and Stat6 gene expression was turned on after P. gingivalis infection in BALB/cByJ mice but not in A/J mice. The basal expression of interleukin-15 (Il15) in the gingiva and the basal expression of p-selectin (Selp) in the spleen were higher in the resistant A/J mice than in the susceptible BALB/cByJ mice. In the resistant A/J mice the expression of no genes detectably changed in the gingiva after infection. These results suggest a molecular phenotype in which discrete sets of differentially expressed genes are associated with genetically determined susceptibility (Il1b, Tnf, and Stat6) or resistance (Il15 and Selp) to alveolar bone loss, providing insight into the genetic etiology of this complex disease.

Impact of IL-1 genotype and smoking status on the prognosis of osseointegrated implants

AIM

This study evaluated the impact of the IL-1 genotype and smoking status on the prognosis and development of complications of osseointegrated implants.

MATERIAL AND METHODS

The clinical charts of 180 consecutively admitted patients were analyzed with respect to the occurrence of biological complications in conjunction with oral implants. Biologic complications were defined as clinical conditions with suppuration from the peri-implant sulcus, development of a fistula or peri-implantitis with radiologic bone loss. All patients had received one or more ITI dental implants, which had been in function for at least 8 (range: 8-15) years. This patient population had received 292 implants. From these, 51 implants in 34 patients showed late (infectious) biologic complications, and 241 implants had survived without any biologic complications at all.

RESULTS

Of the 180 patients, 53 were smokers, who were subdivided in a series of classes according to their intensity of smoking and 127 were never smokers. Sixty-four of 180 (36%) patients tested positive for the IL-1 genotype polymorphism. This prevalence corresponds to previous reports for the prevalence of European descent populations. The results for the non-smoking group indicated no significant correlation between implant complications and a positive IL-1 genotype. However, there was a clear association for heavy smokers between a positive IL-1 genotype and implant complications. 6 of 12 or half of the heavy smokers and IL-1 genotype-positive patients had either an implant failure, i.e. loss of implant, or a biologic complication during the follow-up period.

CONCLUSIONS

These findings have led to the conclusion that there is a synergistic effect between a positive IL-1 genotype and smoking that puts dental implants at a significantly higher risk of developing biologic complications during function.

Alleles of the gene encoding IL-1alpha may predict control of plasma viraemia in HIV-1 patients on highly active antiretroviral therapy

OBJECTIVE

Some HIV patients treated with highly active antiretroviral therapy (HAART) do not resolve their plasma viraemia or HIV RNA can reappear after a period of virological control. We investigate whether polymorphisms in cytokine genes affect the control of plasma HIV RNA over 5 years on HAART.

DESIGN

The study utilized adult HIV-infected patients in Western Australia. Plasma HIV-RNA levels were assessed from commencement of HAART in patients who had a CD4 T-cell count less than 100 cells/microl before HAART and achieved immune reconstitution assessed by CD4 T-cell counts.

RESULTS

Control of plasma viraemia could be predicted from carriage of allele 2 at position -889 in the IL1A gene (IL1A-889*2). This was significant when assessed by the proportion of patients with a plasma HIV-RNA level of 400 copies/ml or less (P = 0.002). At 48 months post-HAART, proportions were approximately 0.76, 0.51 and 0.32 for IL1A (1,1), (1,2) and (2,2) patients, respectively. The outcome was independent of the patients' CD4 T-cell counts before or on therapy, drug regimen or age. Polymorphisms in IL6, TNFA, IL1B or IL12B had less significant effects, which became marginal when IL1A was included in the statistical model. IL1A-889 was in linkage disequilibrium with a non-synonymous polymorphism at IL1A+4845.

CONCLUSION

Alleles carried at IL1A-889 or IL1A+4845 may predict the control of HIV replication in previously immunodeficient patients responding to HAART.

Interleukin 10 gene promoter polymorphisms are associated with chronic periodontitis

BACKGROUND

Chronic periodontitis (CP) is characterized by an inflammation in the supporting tissues of the teeth caused primarily by bacterial infection. Interleukin 10 (IL10) is an anti-inflammatory cytokine whose genetic polymorphisms may influence the expression of the protein.

OBJECTIVE

In this study we investigated the hypothesis that single-nucleotide polymorphisms (SNPs) in the promoter of IL10 gene might be related to CP.

MATERIALS AND METHODS

DNA was obtained from n=67 CP patients and n=43 control subjects. All studied individuals were non-smokers. The -1087 SNP was investigated by DNA sequencing, and the -819 and -592 SNPs by restriction fragment length polymorphism of PCR products.

RESULTS

Frequencies of -819 and -592 SNPs showed differences between the control and CP groups. The ACC haplotype was more prevalent in the control group and the ATA haplotype more prevalent in the CP group. The ATA haplotype seemed to increase susceptibility to CP in women (odds ratio (OR)=2.57). The heterozygous haplotype GCC/ACC was predominant in the control group (OR=8.26; p=0.001).

CONCLUSIONS

Specific haplotypes and SNPs in IL10 gene are associated with susceptibility to CP in Brazilian patients.

Can we successfully maintain risk patients?

The most fundamental premise in the current view of periodontal disease is that not all individuals are at equal risk for disease and disease progression. Studies reveal that about 5-20% of the population is at risk for severe disease progression. The purpose of this paper is to define at-risk patients, review risk factors and indicators of disease progression, and outline an evidence-based strategy that includes both self-care and professional care for maintaining periodontal health. Risk factors/risk indicators considered include history of previous disease, increased pocket depth and loss of clinical attachment, frequency of dental care, specific bacterial pathogens, and systemic/environmental host factors such as smoking, diabetes mellitus, genetics, and stress. Because host factors may have more influence on disease progression than periodontal pathogens, personal and professional maintenance care must include the role of the host in periodontal disease progression. By examining the evidence surrounding these complex issues, dentists and dental hygienists are able to determine the extent to which evidence supports available approaches to maintain periodontal health and control disease progression.