Ricardo P. Teles, DDS, DMSc

The impact of subgingival biofilms on in vivo expression of inflammatory biomarkers
Periodontal diseases are initiated by bacterial species living in biofilms at or below the gingival margin and progress largely as a result of the inflammation initiated by a specific subset of subgingival species. The interplay between the host and subgingival species have been investigated, for the most, examining in vitro interactions between isolated bacterial species and single host cell types. However, since subgingival biofilms form a complex polymicrobial community, the tipping point in the balance between periodontal health and disease depends on the interplay between the host and the microbial community as a whole. 

The host immune responses to subgingival biofilms are orchestrated by cytokines. These molecular messengers are determinants of efficient innate and adaptive responses and allow fine tuning of the interplay among the various components of the immune system. Shifts in cytokine levels appear to be guided by the microbiota present at each stage of periodontitis, however, there are very limited data regarding the changes in cytokine levels in relation to the total mass and composition of subgingival biofilms. It has been difficult to measure the interactions between polymicrobial biofilms and the cytokine network in periodontal infections because: 1) There are so many bacterial species and cytokines involved; 2) The level of these species and cytokines are quite low 3) There is great variability in both host and bacterial components from periodontal site to site in either periodontally diseased or healthy individuals. In the past decade high throughput methods have been devised that can permit simultaneous quantification of multiple bacterial species and cytokines at large numbers of individual sites. For the first time we can examine in detail the remarkable interplay between the microbial composition of subgingival biofilms and the host’s response to the microbial communities on a site by site basis in vivo.

In our laboratory we have been using a multiplex bead assay (Luminex) coupled with the checkerboard DNA-DNA hybridization technique for the high-throughput quantification of cytokines and other inflammatory biomarkers present in the gingival crevicular fluid (GCF) as well as levels of subgingival species at the same sites. The overall objective is to investigate in vivo the effects of subgingival biofilm composition on the local cytokine expression profile in chronic periodontitis and in periodontally healthy subjects. In addition, the effects of periodontal treatment and biofilm re-development on clinical parameters, levels of subgingival microbial species and levels of GCF cytokines and other host derived biomarkers has also been a focus of our studies. The goal of this line of research is to fill a gap in our knowledge regarding the cytokine expression profiles associated with specific polymicrobial subgingival biofilms and the cross-regulation within the cytokine network. Clarification of the key immune mechanisms involved in the response to polymicrobial biofilms associated with periodontal diseases holds immense promise to unlock novel therapeutic and diagnostic approaches to these infections.

Determining biomarkers of periodontal disease progression
Periodontal diseases are the most common cause of tooth loss among adults in the United States and recent studies suggested that they increase the risk for systemic conditions such as: cardiovascular diseases, diabetes, respiratory diseases and can affect reproductive outcome. Further, periodontal diseases progress through “bursts” of activity followed by periods of quiescence. Early accurate identification of individuals and/or sites that are undergoing active disease progression is critical to signal the need for immediate intervention to minimize tooth loss, allow for proper allocation of resources to treat the most vulnerable individuals and limit the potential systemic sequelae of these infections. However, there are no practical clinical means of identifying periodontal sites and/or subjects that are progressing. Development of a point-of-care (POC) test for disease activity would allow clinicians to: 1) Detect subjects at high risk for disease progression; 2) Determine immediacy of need for treatment; 3) Determine the best course of therapy: 4) Evaluate treatment outcome.

Gingival crevicular fluid (GCF) is a convenient non-invasive diagnostic fluid to measure site levels of host biomarkers that are associated with periodontal disease. Certain GCF biomarkers have been examined for their diagnostic properties with promising preliminary results. Although it is generally accepted that identification of GCF biomarkers associated with periodontal tissue destruction should be attainable, what is not known is which components of GCF will present the best diagnostic and prognostic properties. Gingival crevicular fluid is the primary source of several biomarkers associated with periodontal disease in whole saliva. If whole saliva contains GCF from all of the relevant periodontal sites, then this easily collected biological sample may provide subject-level assessment of periodontal disease status.

Because periodontal diseases are caused by the interplay between the subgingival biofilm and the host response, a strategy seeking to identify oral-fluid derived biomarkers of periodontal disease progression should explore both sides of this pathogenic process. Because half of the subgingival microbiota is composed of uncultivated/unrecognized bacterial species, our laboratory uses the recently developed RNA-oligonucleotide quantification technique (ROQT) to quantify both uncultivated and cultivable bacterial taxa. To date, oral fluid analyses (GCF and saliva) and microbial species have been individually examined for their diagnostic potential. However, diagnostic power can be dramatically enhanced when several biomarkers are evaluated concomitantly in a multi-biomarker approach. Better biomarkers are urgently needed to improve periodontal disease diagnosis, guide therapy, monitor activity and evaluate treatment response.

The primary objective of this line of research is to identify biomarkers of periodontal disease progression. The central hypothesis is that a combination of host analytes and subgingival species will be effective as biomarkers of periodontal disease progression. This hypothesis is firmly based on strong preliminary data and our current understanding of periodontal disease pathogenesis. The long-term goal of this research is to develop a POC diagnostic test that will help clinicians identify sites and/or subjects that are susceptible to periodontal disease progression.

Selected Publications

Teles RP, Sakellari D, Konstantinidis A, Socransky SS, Haffajee AD. (2009) Application of the checkerboard immunoblotting technique to the quantification of host biomarkers in gingival crevicular fluid. J. Periodontol. 80(3):447-456.

Teles RP, Likhari V, Socransky SS, Haffajee AD. (2009) Salivary cytokine levels in subjects with chronic periodontitis and in periodontally healthy individuals: A cross-sectional study. J. Periodontal Res. 44(3):411-417.

Teles RP, Teles FR. (2009) Antimicrobial agents used in the control of periodontal biofilms: effective adjuncts to mechanical plaque control?. Braz. Oral Res. 1:39-48.

Haffajee AD, Teles RP, Patel MR, Song X, Veiga N, Socransky SS. (2009) Factors affecting human supragingival biofilm composition. I. Plaque mass. J. Periodontal Res. 44(4):511-519.

Haffajee AD, Teles RP, Patel MR, Song X, Yaskell T, Socransky SS. (2009) Factors affecting human supragingival biofilm composition. II. Tooth position. J. Periodontal Res. 44(4):520-528.

Haffajee AD, Yaskell T, Torresyap G, Teles R, Socransky SS. (2009) Comparison between polymerase chain reaction-based and checkerboard DNA hybridization techniques for microbial assessment of subgingival plaque samples. J. Clin. Periodontol. 36(8):642-649.

Haffajee AD, Yaskell T, Torresyap G, Teles R, Socransky SS. (2009) Comparison between polymerase chain reaction-based and checkboard DNA hybridization techniques for microbial assessment of subgingival plaque samples. J. Clin. Periodontol. 36(8):642-649.

Teles RP, Patel M, Socransky SS, Haffajee AD. (2008) Disease progression in periodontally healthy and maintenance subjects. J. Periodontol. 79(5):784-794.

Bogren A, Teles RP, Torresyap G, Haffajee AD, Socransky SS, Wennstrom JL. (2008) Locally delivered doxycycline during supportive periodontal therapy: A 3-year study. J. Periodontol. 79(5):827-835.

Teles RP, Bogren A, Patel M, Wennstrom JL, Socransky SS, Haffajee AD. (2007) A three-year prospective study of adult subjects with gingivitis II: microbiological paramaters. J. Clin. Periodontol. 24(1)7-17.

Teles RP, Haffajee AD, Socransky SS. (2006) Microbiological goals of periodontal therapy. Periodontol. 2000 42(1):180-218.

Haffajee AD, Teles RP, Socransky SS. (2006) The effect of periodontal therapy on the composition of the subgingival microbiota. Periodontol. 2000 42(1):219-258.