15 December 2021

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Screening and monitoring of periodontitis by analyzing the levels of myeloid proteins in saliva

Lara Figini

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Periodontitis is a very widespread chronic disease, characterized by microbiota-induced inflammation of the supporting tissues of the tooth and can also lead, if neglected, to tooth loss as well as contributing to the systemic inflammatory load. In cases of periodontitis, immune cells infiltrate the periodontal tissues producing high concentrations of cytokines and proteolytic enzymes, such as matrix metalloproteinases (MMPs), which mediate tissue damage leading to loss of function and clinical disease. Among the immune cells, myeloid cells, which produce enzymes that undermine the integrity of the oral mucosa and mediate alveolar bone resorption, play a significant role in the pathogenesis of periodontitis. Therefore, myeloid cell-reflecting molecules are potential biomarkers for screening for periodontitis and for assessing response to therapy.

Materials and Methods
In a clinical study, published on Journal of Clinical Periodontology, November 2021, the authors evaluated the salivary levels of myeloid markers related to periodontal disease and their potential screening capacity, as well as the effects of periodontal treatment on these markers in patients with periodontitis. Participants with healthy periodontium (n = 60) and with gingivitis (n = 63) and periodontitis (n = 72) were recruited. Patients with periodontitis received non-surgical treatment and were re-examined after 3 and 6 months. Unstimulated saliva was collected at baseline time 0 and at 1, 3 and 6 months after periodontal therapies. Levels of factor-1 (CSF-1), interleukin-34 (IL-34), S100A8 / A9, S100A12, hepatocyte growth factor (HGF), IL-1β, and matrix metalloproteinase- 8 (MMP-8) were analyzed by immunoassays.

Results
CSF-1, S100A8 / A9, S100A12, IL-1β, MMP-8 and HGF were significantly more elevated in the saliva of patients with periodontitis and gingivitis compared to that of healthy subjects. IL-34 was significantly lower in periodontitis than in both healthy individuals and in patients with gingivitis. IL-34 significantly increased 3 months after treatment, while IL-1β and MMP-8 decreased 1 month after therapy. Patients were then divided into subjects with high-level and low-level S100A8 / A9 periodontitis, and subjects with high levels had more bleeding, deeper pockets, and higher S100A12.

Conclusions
From the data of this study, which must be confirmed in other similar studies, it can be concluded that the salivary levels of myeloid markers are altered in periodontitis and are partially modulated by periodontal treatment. Measurement of S100A8 / A9 in saliva can identify distinct groups of patients with periodontitis (high-level and low-level).

Clinical implications
Myeloid cells are essential for the inflammatory process in periodontitis. Therefore, measuring the molecules that reflect their functions in saliva has the potential to improve it screening and monitoring of periodontal inflammation. Measuring myeloid markers in saliva can be helpful in evaluating periodontal disease. Assessment of S100A8 / A9 in saliva can inform the identification of distinct groups of patients with periodontitis, potentially helping patient monitoring and treatment.

For additional information: Levels of myeloid-related proteins in saliva for screening and monitoring of periodontal disease