Periodontal disease identified using salivary biomarkers

By Sarah Guy, medwireNews Reporter

Markers of inflammation found in saliva could be used to identify periodontal disease in large epidemiologic surveys, avoiding the need for cumbersome and expensive tests, suggest researchers.

Their study results show that patients with severe periodontitis have elevated salivary concentrations of the inflammatory mediators interleukin (IL)-1β (a pro-inflammatory cytokine), IL-6, IL-8; the collagen-cleaving enzyme matrix metalloproteinase-8 (MMP-8), and lysozymes, which are part of the innate immune system.

The ratio of MMP-8 to tissue inhibitor of MMP (TIMP) was also significantly higher among study participants with severe periodontitis compared with their unaffected counterparts, say the researchers.

The associations remained after compensation for age, gender, and smoking, write Nilminie Rathnayake (Karolinska Institutet, Huddinge, Sweden) and colleagues in the Journal of Clinical Periodontology.

The study cohort included 443 individuals aged 20-89 years old, who were examined between March 2007 and November 2008. Participants also completed a questionnaire regarding their oral health and dental history.

The biomarkers included in the analysis could be detected in more than 99% of all participants' saliva samples. MMP-8 and IL-1β were found at significantly higher concentrations in the 49 patients who had periodontal disease plus horizontal supporting bone loss greater than one-third of the root length in more than 30% of sites, than in those with periodontal disease and bone loss in less than 30% of sites (n=89) or no bone loss (n=303).

"These differences remained significant after compensation for differences in gender, age, and smoking habits across the three groups," write Rathnayake et al.

In addition, patients who smoked (n=75) had significantly lower levels of IL-8 and a significantly lower MMP-8/TIMP-1 ratio, and borderline significantly lower levels of MMP-8, than their peers who were nonsmokers (n=366).

Finally, in analysis of biomarkers and clinical variables, the most pronounced correlation was between IL-1β and the number of deep pockets greater than 5 mm.

While the study shows that certain biomarkers in saliva have the potential to be used as a diagnostic tool, they are all indicators of inflammation rather than tissue destruction, remark the authors.

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