Local and Systemic Biomarkers in Gingival Crevicular Fluid Increase

J Clin Periodontol 2010; 37: 30–36 doi: 10.1111/j.1600-051X.2009.01506.x

Tracy R. Fitzsimmons1, Anne E. Local and systemic biomarkers in Sanders2, P. Mark Bartold1 and Gary D. Slade2 1Centre for Orofacial Research and Learning, gingival crevicular ﬂuid increase Colgate Australia Clinical Dental Research Centre, School of Dentistry, University of Adelaide, Adelaide, SA, Australia; odds of periodontitis 2Australian Research Centre for Population Oral Health, School of Dentistry, University of Adelaide, Adelaide, SA, Australia Fitzsimmons TR, Sanders AE, Bartold PM, Slade GD. Local and systemic biomarkers in gingival crevicular ﬂuid increase odds of periodontitis. J Clin Periodontol 2010; 37: 30–36. doi: 10.1111/j.1600-051X.2009.01506.x.

Abstract Aim: To determine the independent and combined associations of interleukin-1b (IL-1b) and C-reactive protein (CRP) in gingival crevicular fluid (GCF) on periodontitis case status in the Australian population. Materials and Methods: GCF was collected from 939 subjects selected from the 2004–2006 Australian National Survey of Adult Oral Health: 430 cases had examiner- diagnosed periodontitis, and 509 controls did not. IL-1b and CRP in GCF were detected by enzyme-linked immunosorbent assays. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated in bivariate and stratified analysis and fully adjusted ORs were estimated using multivariate logistic regression. Results: Greater odds of having periodontitis was associated with higher amounts of IL-1b (OR 5 2.4, 95% CI 5 1.7–3.4 for highest tertile of IL-1b relative to lowest tertile) and CRP (OR 5 1.9, 95% CI 5 1.5–2.5 for detectable CRP relative to undetectable CRP). In stratified analysis, there was no significant interaction between biomarkers (p 5 0.68). In the multivariate analyses that controlled for conventional periodontal risk factors, these relationships remained (IL-1b OR 5 1.8, 95% CI 5 1.1–2.6; CRP OR 5 1.7, 95% CI 5 1.3–2.3). Conclusions: Elevated odds of clinical periodontitis was associated independently Key words: C-reactive protein; gingival with each biomarker. This suggests that people with elevated biomarkers indicative of crevicular fluid; interleukin-1b; periodontitis either local (IL-1b) or systemic (CRP) inflammation are more likely to suffer from periodontal disease. Accepted for publication 14 October 2009

Numerous studies have shown that bio- retson et al. 2002, Bostanci et al. 2007, from the periodontium become elevated markers of inflammatory response are Zhong et al. 2007). These biomarkers in response to periodontitis only as a elevated in people with periodontitis include cytokines known to be produced consequence of locally produced bio- compared with healthy controls (Mogi locally in periodontal tissues [e.g. inter- markers in the periodontium. If that et al. 1999, Gamonal et al. 2000, Engeb- leukin-1b (IL-1b)] as well as acute phase were so, then the association between reactants that predominantly are pro- CRP and periodontitis would be depen- duced in tissues remote from the infection dent upon IL-1b levels in the period- Conflict of interest and source of [e.g. C-reactive protein (CRP), predomi- ontium. However, if both CRP and funding statement nantly produced in liver]. Our own case– IL-1b are independently associated The authors declare that there are no control study confirmed these findings in with periodontitis, it would suggest the conflicts of interest in this study. samples of gingival crevicular fluid relationship is more complex, and This study was supported by grants from (GCF) collected from a representative potentially could offer insight into sepa- the National Health and Medical Res- population-based sample of Australian rate mechanisms by which local and earch Council (Project Grants #349514 adults in which we measured IL-1b and systemic inflammatory responses are and #299060). Dr. Sanders is supported CRP (Fitzsimmons et al. 2009). related to the disease. by a NHMRC Sidney Sax Public Health It is possible that inflammatory bio- The relationship between inflamma- Fellowship (#399222). markers produced in tissues remote tory biomarkers and periodontitis is 30 r 2009 University of Adelaide GCF IL-1b, CRP and periodontitis 31 most likely bidirectional. On the one Consequently, in the current analyses, probing depths were recorded. Where hand, bacterial infection in the perio- we focus on periodontitis as the depen- all probing depth measurements were dontal tissues stimulates a local immune dent variable with the primary aim to o4 mm, a simple random sampling response involving the production and determine the combined effects of each method was used to select all four sites. release of several inflammatory media- biomarker on occurrence of clinical Otherwise, a stratified random sampling tors into the surrounding tissue. The role periodontitis. Our hypothesis was that method was used to collect GCF from of one such mediator, IL-1b, is well each biomarker would contribute inde- up to two sites with probing depth 4 mm, known in periodontal disease progres- pendently to the odds of periodontitis, and the remaining samples from sites sion (Lo et al. 1999, Graves & Cochran and that their effects would be observa- with probing depth o4 mm. 2003) and as an indicator of active ble even after adjusting for conventional inflammation. Produced locally at the risk factors for periodontitis. Such a Case definition site of infection by a number of cells finding is consistent with the notion involved in host defence against perio- that both local and systemic inflamma- For this study, 939 examined survey dontal pathogens including macro- tory processes contribute to the risk of participants were selected using a phages, neutrophils and gingival having periodontitis. case–control study design. Cases were fibroblasts (Takahashi et al. 1995, Lo If this hypothesis is supported, find- people with two or more interproximal et al. 1999, Steffen et al. 2000), IL-1b is ings will build on existing evidence to sites with X4 mm clinical attachment initially released to combat infection. provide ‘‘proof-of-principle’’ support loss and two or more interproximal sites However, persistent infection leads to for a potential etiological association with PD of X5 mm or more were the dysregulation of the immune system between both sources of inflammation defined as moderate or severe perio- and a cascade of events, initiated by IL- and periodontitis case status. dontitis cases, while non-cases had less 1b, results in chronic inflammation of extensive disease (Page & Eke 2007). the periodontal supporting tissues, cul- All examined NSAOH subjects who met minating in destruction of alveolar Materials and Methods criteria as periodontal cases were bone mediated via IL-1b regulation of included in this study, while NSAOH Study design and sampling osteoclasts (Graves & Cochran 2003). subjects who were non-cases were These inflammatory processes in perio- The current case–control study as pre- sampled at random for this study to dontal tissues can trigger a more gen- viously described (Fitzsimmons et al. select an approximately equivalent eralized systemic response in tissues 2009) was nested within the National number of non-cases for this study. remote from the periodontium, such as Survey of Adult Oral Health (2004– Non-cases from the NSAOH subjects the liver. 2006) (NSAOH) (Slade et al. 2007). were selected at random using a random Meanwhile, inflammatory processes The University of Adelaide’s Human number generator in SAS (SAS v.9.2, elsewhere in the body can contribute to Research Ethics Committee granted SAS Institute, Cary, NC, USA), with periodontitis. Some systemic diseases approval for the National Survey. Dur- frequency matching within states/terri- (such as diabetes) that increase risk of ing the survey, 5505 people underwent tories to achieve similar numbers of periodontitis also contribute to inflam- standardized oral epidemiological cases and non-cases within each juris- matory responses in numerous tissues, examinations. All examined subjects diction. increasing systemic levels of each bio- provided written informed consent marker. Finally, there is speculation that before the examination. Examinations GCF collection and analysis a common underlying hyper-inflamma- included measurements of periodontal tory phenotype might predispose peo- pocket depth (PD) and gingival reces- GCF was collected on two PerioPapert ple, both to periodontitis and systemic sion on all teeth except third molars. strips (Oraflow Inc., Plainview, NY, inflammation (Offenbacher & Beck Three sites were assessed per tooth: USA) per site as previously described 2005). These bidirectional effects mean mesiobuccal, mid-buccal and distobuc- (Fitzsimmons et al. 2009). Briefly, the that elevated levels of inflammatory cal. Clinical periodontal attachment area was isolated from saliva with cot- biomarkers may signify both the causes level was calculated as the sum of PD ton rolls and air dried before placing the and consequences of periodontitis. and recession at each site during subse- strip into the gingival crevice for 10 s. Given the likely bidirectional causal quent data management. Following Paper strips were wrapped in foil before pathways linking periodontitis and probing measurements, up to four perio- shipping to the laboratory by mail where inflammatory biomarkers, it is informa- dontal sites were selected at random they were frozen at 201C until pro- tive to examine these relationships using from among all measured periodontal cessed. GCF samples contaminated with periodontitis both as an explanatory sites and used for collection of GCF blood were processed but excluded from variable and separately as a dependent samples. An algorithm in the computer analysis. GCF was eluted from each variable. In our previous study, we used program recording dental examination individual PerioPapert strip as pre- periodontitis as an explanatory variable data selected four periodontal sites at viously described (Fitzsimmons et al. to show that both IL-1b and CRP in random for collection of GCF samples. 2009). GCF was eluted from Perio GCF were elevated in periodontitis Sites were selected from among all Papert strips by a two-step centrifuga- cases relative to non-cases (Fitzsim- periodontally measured sites within tion method. Each strip was eluted mons et al. 2009). However, we did each person’s mouth, yielding up to separately by adding elution buffer not attempt to determine if elevated two sites with probing depths of at least (1% bovine serum albumin solution, levels of CRP was associated with 4 mm and the remaining sites with shal- R&D Systems, Minneapolis, MN, periodontitis independently of the levels lower probing depths. GCF was col- USA) to the strip and incubating at of IL-1b. lected at four sites where recession and room temperature for 15 min. before r 2009 University of Adelaide 32 Fitzsimmons et al. centrifugation at 3000 g for 5 min. at categories were ‘‘yes’’, ‘‘no’’ and were elevated at older age and among 41C. This process was repeated before ‘‘don’t know’’. The latter were coded males, non-Australian born subjects combining eluted solution (final volume as missing and not used in this analysis. born and former and current smokers 480 ml) from each pair of strips before relative to their respective reference storing at 201C until further analysis groups. Also presenting as a significant by ELISA. Statistical analysis risk indicator was history of chronic Levels of IL-1b and CRP in GCF To test the study hypothesis that IL-1b health conditions. Elevated levels of samples were determined using com- and CRP were significant independent IL-1b were found in subjects with mercially available ELISA kits [R&D predictors of periodontitis, unconditional detectable CRP and among males, the Systems (IL-1b) and Bender MedSys- logistic regression was used to compute non-Australian born and diabetics, rela- tems, Vienna, Austria (CRP)] following unadjusted odds ratios (OR) and corre- tive to females, Australian-born subjects the manufacturer’s guidelines. All stan- sponding 95% confidence intervals (95% and those with no diagnosis of diabetes. dards and samples were assayed in CIs) for these associations. ORs with Detectable levels of CRP were found in duplicate with biomarker concentrations 95% CIs that excluded 1.0 were judged significantly higher proportions of the determined from standard curves gener- to be statistically significant. Odds of aged and medically compromised than ated with KC4 software (BioTek Instru- periodontitis were also examined for in the young and healthy, although the ments, Winooski, VT, USA) using a selected subject socio-demographic association with a history of high blood four-parameter logistic curve-fit (IL- characteristics, cigarette smoking and cholesterol was non-significant. 1b) or linear regression (CRP) analysis. self-reported history of chronic condi- A non-significant statistic for the tions, each of which is a recognized Breslow–Day test (p 5 0.68) was evidence for no effect modification by IL- Quantifying inflammatory biomarkers periodontal risk indicator. The variable hypothesized to modify the association 1b levels in the association between The eluted IL-1b was multiplied by 0.48 between CRP and periodontitis was IL- CRP and periodontitis (Table 2). Hence to yield the amount in picograms at each 1b. Consequently to test for potential no interaction term was entered into the periodontal site, and its natural log was interaction, the association between CRP multivariable logistic regression model. computed to overcome the skewed nat- and periodontitis was computed within After adjustment for covariates ure of its distribution. For each person, each stratum of IL-1b (low, moderate, (Table 3), IL-1b and detectable CRP the mean value of log (amount) was high). Crude ORs were compared with remained significantly associated with computed from among all sites assayed. these stratum-specific estimates using periodontitis risk. Furthermore, odds of For the purpose of these analyses this the Breslow–Day test for homogeneity periodontitis were elevated 80% for continuous variable was split into of the odds. Finally, significant predic- each additional decade of life lived. approximately equal-sized tertiles tors were entered into a multivariate Males and non-Australian born subjects labelled ‘‘Low’’ (a mean of 1.0 pg or logistic regression model to determine remained about twice as likely to be a less of eluted IL-1b among assayed whether, and to what extent, elevated case and current smokers had odds sites), ‘‘Moderate’’ (a mean of biomarkers remained significant perio- elevated 3.6-fold (95% CI 5 2.4–5.5) 41.0 pg to o3.3 pg of eluted IL-1b) dontitis risk predictors after adjustment relative to subjects who had never and ‘‘High’’ (a mean of 3.3 pg or more). for conventional risk indicators. To smoked. The lower limit of detection of the investigate the sensitivity of these find- When the odds of severe periodontitis CRP ELISA was 3 pg/ml. The eluted ings to the threshold used to define was evaluated in a logistic regression concentration of CRP fell below the periodontal case status, we repeated the model that excluded cases of moderate limit of detection for 58% of sites, so logistic regression analysis, excluding periodontitis, both mediators remained the data were dichotomized to indicate subjects with moderate periodontitis, to statistically significant. There was a whether or not an amount of three or model the odds of having severe perio- similar magnitude of effect for IL-1b more picograms per millilitre was dontitis. All analyses were conducted (for the mid-tertile of IL-1b,OR5 1.5, detected. A person-level variable was using SAS v.9.2 (SAS Institute). 95% CI 5 0.7–2.9; for the high tertile of computed to indicate whether or not the IL-1b,OR5 1.9, 95% CI 5 1.0–3.6), study subject had detectable CRP at this and a slightly stronger effect for CRP threshold. (OR 5 3.3, 95% CI 5 2.0–5.5). The cov- Results ariates listed in Table 3 also remained Of the 939 subjects selected from the statistically significant, with similar or Self-reported socio-demographics and 2004–2006 Australian National Survey greater ORs [e.g. up to 7.8 (95% medical history of Adult Oral Health, 430 were exam- CI 5 4.0–15.1) for current smoking]. Self-reported information about demo- iner-diagnosed periodontitis cases, graphics, smoking history, self-rated and the remaining 509 non-cases. In health and medical conditions were unadjusted analysis (Table 1) a dose– asked either during a telephone inter- response effect was evident of increas- Discussion view conducted before the examinations ing odds of periodontitis at elevated This study investigated the combined or using a questionnaire completed on levels of IL-1b. Likewise subjects with effects of IL-1b and CRP in GCF on the day of the examination. For each detectable CRP were almost twice as presence of periodontitis in the Austra- medical condition, subjects were asked likely to be cases as those with unde- lian population. Increased odds of clin- ‘‘Has a doctor or other health profes- tectable levels of this biomarker (OR ical periodontitis was associated sional ever told you that you have . . .’’ 1.9, 95% CI 1.5–2.5). Confirming pre- independently with elevated biomarkers (e.g. high blood pressure) and response vious findings, odds of periodontitis that are indicative of local (IL-1b)or r 2009 University of Adelaide GCF IL-1b, CRP and periodontitis 33

Table 1. Inﬂuence of biomarker presence in GCF on odds of periodontitis Predictor Number of subjects Percentage with periodontitis OR (95% CIn) IL-1bw CRPz

Low Medium High Detectable

IL-1b Low-tertile 267 33.3 Ref.§ – – – 25.1 Mid-tertile 322 46.3 1.7 (1.2–2.4) – – – 40.7 High-tertile 350 54.9 2.4 (1.7–3.4) – – – 55.4 p-value o0.01 CRP Undetectable 547 39.1 Ref. 36.6 34.9 28.5 – Detectable 392 55.1 1.9 (1.5–2.5) 17.1 33.4 49.5 – p-value o0.01 Age (years) 15–44 306 22.6 Ref. 33.7 33.0 33.3 35.0 45–59 318 50.3 3.5 (2.5–4.9) 27.7 33.3 40.0 42.8 601 315 63.8 6.1 (4.3–8.6) 24.1 36.5 39.4 47.3 p-value 0.11 o0.01 Gender Female 542 37.3 Ref. 30.3 36.2 33.6 42.4 Male 397 57.4 2.3 (1.7–3.0) 25.9 31.7 42.3 40.8 p-value 0.02 0.62 Country of birth Australia 692 39.7 Ref. 30.9 35.7 33.4 41.8 Elsewhere 247 62.8 2.6 (1.9–3.4) 21.5 30.4 48.2 41.7 p-value o0.01 0.99 Smoking status Never 457 37.9 Ref. 29.8 35.2 35.0 39.8 Former 307 50.5 1.7 (1.2–2.2) 28.0 34.9 37.1 44.3 Current 175 58.3 2.3 (1.6–3.3) 25.7 30.9 43.4 42.3 p-value 0.41 0.46 Diabetes history No 879 44.7 Ref. 29.6 34.5 36.2 40.7 Yes 60 61.7 2.0 (1.2–3.4) 15.0 31.7 53.3 56.7 p-value 0.01 0.02 Cardiovascular disease history No 898 44.9 Ref. 28.8 34.6 36.5 41.0 Yes 37 70.3 2.9 (1.4–5.9) 16.2 27.0 56.8 62.2 p-value 0.04 0.01 High blood pressure No 674 42.0 Ref. 29.4 34.1 36.5 37.2 Yes 251 57.4 1.9 (1.4–2.5) 25.9 35.1 39.0 53.8 p-value 0.56 o0.01 High blood cholesterol No 649 41.5 Ref. 28.8 36.1 35.1 40.8 Yes 266 57.1 1.9 (1.4–2.5) 25.9 31.2 42.9 42.9 p-value 0.09 0.57 General health Good to excellent 825 44.0 Ref. 28.9 34.6 36.6 40.5 Poor to fair 114 58.7 1.8 (1.2–2.7) 25.4 32.5 42.1 50.9 p-value 0.51 0.03 n95% CI for OR. w Percentage of people with low (o1.0 pg), medium (1.0 to o3.3 pg) and high (X3.3 pg) amounts of IL-1b eluted from GCF. zPercentage of people with detectable CRP in GCF. §Reference group for OR. CI, confidence interval; OR, odds ratio; IL-1b, interleukin-1b; CRP, C-reactive protein; GCF, gingival crevicular fluid. systemic (CRP) inflammation. In addi- These findings are consistent with nificantly associated with a history of tion a number of socio-demographic those from a previous study, which diabetes or cardiovascular disease. variables were also associated with demonstrated that increased levels of Furthermore, detectable levels of CRP increased odds of having periodontitis both IL-1b and CRP in GCF were in GCF were also influenced by a his- and these included age, gender, smoking associated with age and country of birth tory of high blood pressure and self- status and country of birth. The findings (Fitzsimmons et al. 2009). In addition to reported poor health. These findings generally were similar when the more these associations, the present study strengthen the notion that periodontitis stringent case definition of severe perio- determined that the levels of IL-1b and involves inflammatory responses that dontitis was used. the presence of CRP in GCF were sig- are associated with local and systemic r 2009 University of Adelaide 34 Fitzsimmons et al.

Table 2. Odds ratios (OR) and corresponding 95% confidence intervals (CI) between C-reactive needed to determine the clinical signifi- protein and periodontitis case status, stratified by levels of Interleukin-1b cance of this threshold. Interleukin-1b C-reactive Number of Periodontitis OR (95% CI) The presence of CRP in GCF in the (tertiles of amount) protein subjects cases (%) current study also builds on the growing body of evidence supporting a relation- Low Undetectable 200 31.5 Ref.n ship between periodontal disease and Detectable 67 38.8 1.4 (0.8–2.5) systemic inflammatory conditions such Medium Undetectable 191 41.2 Ref. as diabetes, cardiovascular disease and Detectable 131 53.4 1.6 (1.0–2.5) rheumatoid arthritis (Mercado et al. High Undetectable 156 46.1 Ref. Detectable 194 61.9 1.9 (1.2–2.9) 2001, Persson et al. 2003, Perrino 2007). Associations between these con- nReference group for OR. ditions and periodontitis are most likely w2 (2df) 5 0.68, p 5 0.77 from Breslow–Day test of homogeneity of odds ratios among three tertiles mediated by increased inflammatory of IL-1b. burden and the induction of acute phase proteins such as CRP (D’Aiuto et al. 2004, Joshipura et al. 2004, Bizzarro et Table 3. Multivariate logistic regression model predicting odds of periodontitis (n 5 938) al. 2007, Abou-Raya et al. 2008). Of these associations, one of the most sig- Predictor Odds ratio (95% confidence interval) nificant appears to be the increase in Interleukin-1b CRP levels in people with periodontitis. Low Ref.n As demonstrated by us and others, this Mid 1.6 (1.1–2.6) has been implicated as a risk factor for High 1.8 (1.2–2.6) future cardiovascular events (Wu et al. C-reactive protein 2000, D’Aiuto et al. 2004, Sun et al. Undetectable Ref. 2009). Detectable 1.7 (1.3–2.3) Age While there is accumulating evidence Per 10 year increment 1.8 (1.6–2.0) implicating periodontitis as a risk factor Gender for other chronic conditions, the bidir- Female Ref. ectional nature of these associations Male 1.9 (1.4–2.6) needs to be recognized and analysed. Smoking For example, in our study the odds of Never Ref. having periodontitis was increased Former 1.3 (1.0–1.9) approximately 2.5 by IL-1b and two Current 3.6 (2.4–5.5) Country of birth times by detectable CRP in unadjusted Australia Ref. analysis. Adjusted ORs were slightly Elsewhere 2.2 (1.5–3.1) lower, with high levels of IL-1b and n detectable CRP increasing the odds of Reference group for odds ratio. having periodontitis by 1.8 and 1.7 times, respectively. These data are similar to those reported by Linden et al patterns of inflammation and that sev- While increased levels of CRP in (2008) where the adjusted OR of perio- eral systemic inflammatory conditions GCF of periodontitis patients noted in dontitis in a multivariable analysis was may impact on periodontitis status pat- the present study are consistent with increased by increased serum levels of terns. Although this study cannot iden- previous reports of increased CRP in CRP to 2.49 (95% CI 5 1.16–5.35). The tify the tissues in which each mediator serum from subjects with periodontitis slight difference in values reported in was produced, it seems likely that CRP (Slade et al. 2000, Glurich et al. 2002, these two studies may be explained by appears in GCF primarily as a serum Salzberg et al. 2006), we cannot com- serum versus GCF detection of CRP and exudate following its production in the ment on the clinical significance, if any, varying differences in periodontitis case liver. This is consistent with other stu- of CRP thresholds used in this analysis. definitions. Irrespective of these differ- dies demonstrating that oral pathogens Because there are no previous studies ences it is apparent that reasons for elicit an immune response with elevated showing clinical significance of CRP increased levels of biomarkers in GCF serum levels of CRP (Noack et al. 2001) thresholds in GCF, we used the assay’s may be the result of periodontal disease and IL-1b (Swoboda et al. 2008). While detection threshold of 3 pg/ml in eluted or they may be a consequence of other it is well accepted that local biomarkers, GCF because it identified sufficient systemic conditions such as cardiovas- including various cytokines, and acute number of subjects to permit analysis cular disease diabetes, or rheumatoid phase proteins, are present in GCF of associations. In a study of 67 subjects arthritis. This important distinction (Armitage 1996) the identification and (including 20 periodontal patients), Tuter remains to be elucidated (Grossi & measurement of CRP in GCF has been et al. (2007) analysed CRP in serum and Genco 1998, Mealey 2006). relatively limited. Besides our previous GCF, and found only a weak correlation An important finding of the present study (Fitzsimmons et al. 2009), there (Pearson’s r 5 0.027, p40.05). Addi- study was that although the stratified are few other reports documenting the tional studies, preferably using longitudi- analysis of the presence of IL-1b presence of CRP in GCF (Sibraa et al. nal designs that predicted risk of together with CRP showed a trend 1991, Tuter et al. 2007). periodontitis or other diseases, would be towards an increased risk of having r 2009 University of Adelaide GCF IL-1b, CRP and periodontitis 35 periodontitis, there was no significant adjusted for conventional risk indica- Gamonal, J., Acevedo, A., Bascones, A., Jorge, interaction between the two biomarkers. tors. Hence we conclude that there was O. & Silva, A. (2000) Levels of interleukin-1 The notion that cytokines and immune no interaction between IL-1b and CRP. beta, -8, and -10 and RANTES in gingival regulators influence the risk of systemic Such independence adds further to our crevicular fluid and cell populations in adult disease is not a new concept. The com- understanding that a chronic disease periodontitis patients and the effect of perio- bination of IL-6 and IL-1b indepen- such as periodontitis may be under dontal treatment. Journal of Periodontology 71, 1535–1545. dently increases the risk of diabetes by bidirectional influences. For example, a Ganapathi, M. K., Rzewnicki, D., Samols, D., approximately three times (Spranger local inflammatory response could be Jiang, S. L. & Kushner, I. (1991) Effect of et al. 2003). Increased CRP and IL-6 expected to result in a local increase in combinations of cytokines and hormones on are also shown to increases the risk of production of inflammatory cytokines synthesis of serum amyloid A and C-reactive diabetes type 2 by 2.3 and 4.2 times, such as IL-1b. However, localized protein in Hep 3B cells. Journal of Immunol- respectively (Pradhan et al. 2001). inflammation can also result in a more ogy 147, 1261–1265. Given that IL-1b and CRP are part of generalized systemic inflammatory Glurich, I., Grossi, S., Albini, B., Ho, A., Shah, a much larger network of cytokines and response in distant organs, including R., Zeid, M., Baumann, H., Genco, R. J. & inflammatory mediators, analysis of the the liver. In addition, individuals who De Nardin, E. (2002) Systemic inflammation combination of these two biomarkers in manifest a hyper-inflammatory pheno- in cardiovascular and periodontal disease: isolation may partially explain these type are predisposed to tissue destruc- comparative study. Clinical and Diagnostic Laboratory Immunology 9, 425–432. results. Other cytokines, particularly tion in response to local periodontal Graves, D. T. & Cochran, D. (2003) The con- tumour necrosis factor-a and IL-6 are infection. Thus local and systemic fac- tribution of interleukin-1 and tumor necrosis two key regulators of IL-1b and CRP, tors may act both independently and factor to periodontal tissue destruction. Jour- respectively. In addition, the induction synergistically in a complex disease nal of Periodontology 74, 391–401. of CRP expression by IL-6 is synergistic such as periodontitis. In order to address Grossi, S. G. & Genco, R. J. (1998) Periodontal with IL-1b (Ganapathi et al. 1991). these issues a prospective cohort study disease and diabetes mellitus: a two-way Well-documented evidence of increased is required. Overall, these data support relationship. Annals of Periodontology 3, levels of IL-6 in GCF from subjects with our original hypothesis that people with 51–61. periodontitis (Mogi et al. 1999, Sun evidence of local or systemic inflamma- Joshipura, K. J., Wand, H. C., Merchant, A. T. et al. 2009) may partially explain the tory biomarkers in GCF are more likely & Rimm, E. B. (2004) Periodontal disease and biomarkers related to cardiovascular dis- present observations of CRP in GCF. to suffer from periodontal disease. ease. 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Clinical Relevance temic (CRP) biomarkers in GCF and with a history of diabetes, cardiovas- Scientific rationale for study: risk of periodontitis. cular disease and hypertension. Increasing evidence suggests that Principal findings: Odds of having Practical implications: Biomarkers periodontal disease consists of local periodontitis were increased by pre- that indicate systemic inflammation and systemic inflammatory compo- sence of local and systemic biomar- observed in periodontitis may con- nents. Most research investigating kers. High levels of IL-1b were tribute not only to periodontal dis- systemic biomarkers has focussed positively associated with a history ease pathogenesis but also the on serum concentrations. We exam- of diabetes, cardiovascular disease inflammatory load of other systemic ined the relationship between the and high blood cholesterol. Detect- conditions such as diabetes and car- presence of local (IL-1b) and sys- able CRP was positively associated diovascular disease.

r 2009 University of Adelaide