GCF RANKL and OPG levels were oppositely regulated in periodontitis, but not gingivitis, resulting in an enhanced RANKL/OPG ratio. This ratio was similar in all three periodontitis groups and may therefore predict disease occurrence.

This study demonstrates that RANKL and osteoprotegerin expression are differentially regulated in various forms of periodontitis, and the relative RANKL/osteoprotegerin ratio appears to be indicative of disease occurrence. This information may confer diagnostic and therapeutic value in periodontitis.

Periodontal diseases are among the most prevalent worldwide, but largely silent, chronic diseases. They affect the tooth-supporting tissues with multiple ramifications on life quality. Their early diagnosis is still challenging, due to lack of appropriate molecular diagnostic methods. Saliva offers a non-invasively collectable reservoir of clinically relevant biomarkers, which, if utilized efficiently, could facilitate early diagnosis and monitoring of ongoing disease. Despite several novel protein markers being recently enlisted by discovery proteomics, their routine diagnostic application is hampered by the lack of validation platforms that allow for rapid, accurate and simultaneous quantification of multiple proteins in large cohorts. Here we carried out a pipeline of two proteomic platforms; firstly, we applied open ended label-free quantitative (LFQ) proteomics for discovery in saliva ( = 67, including individuals with health, gingivitis, and periodontitis), followed by selected-reaction monitoring (SRM)-targeted proteomics for validation in an independent cohort ( = 82). The LFQ platform led to the discovery of 119 proteins with at least 2-fold significant difference between health and disease. The 65 proteins chosen for the subsequent SRM platform included 50 functionally related proteins derived from the significantly enriched processes of the LFQ data, 11 from literature-mining, and four house-keeping ones. Among those, 60 were reproducibly quantifiable proteins (92% success rate), represented by a total of 143 peptides. Machine-learning modeling led to a narrowed-down panel of five proteins of high predictive value for periodontal diseases with maximum area under the receiver operating curve >0.97 (higher in disease: Matrix metalloproteinase-9, Ras-related protein-1, Actin-related protein 2/3 complex subunit 5; lower in disease: Clusterin, Deleted in Malignant Brain Tumors 1). This panel enriches the pool of credible clinical biomarker candidates for diagnostic assay development. Yet, the quantum leap brought into the field of periodontal diagnostics by this study is the application of the biomarker discovery-through-verification pipeline, which can be used for validation in further cohorts.

Tumor necrosis factor-alpha-converting enzyme (TACE) is a metalloprotease which can shed several cytokines from the cell membrane, including receptor activator of NF-kappaB ligand (RANKL). This study aimed to investigate the hypothesis that TACE would be elevated in the gingival crevicular fluid (GCF) of persons with periodontitis. Total TACE amounts in GCF were higher in persons with chronic and aggressive periodontitis than in those with gingivitis or in healthy persons. TACE concentrations in GCF were higher in persons with chronic and aggressive periodontitis than in those with gingivitis, although not significantly higher than in healthy persons. Persons with chronic periodontitis receiving immunosuppressive treatment exhibited over 10-fold lower TACE levels than the other periodontitis groups. TACE was positively correlated with probing pocket depth, clinical attachment levels, and RANKL concentrations in GCF. In conclusion, the increased GCF TACE levels in persons with periodontitis and their positive correlation with RANKL may indicate an association of this enzyme with alveolar bone loss, and may warrant special attention in future therapeutic approaches.

Background: Hypoxia-inducible factor-1 alpha (HIF-1 ) is expressed as an adaptive response to hypoxia, mediates angiogenesis through the expression of vascular endothelial growth factor (VEGF) and can be induced by tumor necrosis factor-alpha (TNF-). This study aimed to investigate the gingival crevicular fluid (GCF) and salivary HIF-1 , VEGF, and TNF-levels in periodontal health and disease.Methods: A total of 87 individuals, 20 generalized aggressive periodontitis (G-AgP), 20 chronic periodontitis (CP), 26 gingivitis patients, and 21 periodontally healthy individuals, were included. Clinical periodontal parameters were recorded; GCF and salivary samples were collected; and HIF-1 , VEGF, and TNF-levels were measured by enzyme-linked immunosorbent assay. Nonparametric tests were used for the statistical analyses.

Abstract. Aim:The aim of the present study was to investigate gingival crevicular fluid (GCF) calprotectin, osteocalcin and cross-linked N-terminal telopeptide (NTx) levels in health along with different periodontal diseases. Material and methods: Twenty chronic periodontitis (CP), 20 generalized aggressive periodontitis (G-AgP), 20 gingivitis and 20 healthy subjects were included. Probing depth, clinical attachment level, plaque index and papillary bleeding index was recorded. GCF calprotectin, osteocalcin and NTx levels were analyzed by enzyme-linked immunosorbent assay (ELISA). Results: CP, G-AgP and gingivitis groups had higher GCF calprotectin total amount compared to healthy subjects (p < 0.008). CP and G-AgP groups had similar, but higher levels compared to gingivitis groups (p < 0.008). CP and G-AgP groups had lower GCF osteocalcin total amount compared to gingivitis and healthy groups (p < 0.008). CP group had higher GCF NTx but lower osteocalcin total amount and osteocalcin/NTx ratio than the G-AgP group (p < 0.008). Conclusions: Our results suggest that elevated GCF calprotectin levels play a role as a reliable inflammatory marker in the pathogenesis of periodontal disease. Fluctuating GCF levels of osteocalcin and NTx might point out to the abnormal bone turnover in periodontitis. Our data document for the first time the role of NTx in the pathogenesis of different periodontal diseases.

Periodontal disease is a globally prevalent microbial infection-induced inflammatory disease that gradually causes the destruction of tooth supporting hard and soft tissues and ultimately tooth loss. The host immune-inflammatory response to microbial dental plaque is the main factor in onset, progression and severity of the disease. 1,2

Oral health is important not only due to the diseases emerging in the oral cavity but also due to the direct relation to systemic health. Thus, early and accurate characterization of the oral health status is of utmost importance. There are several salivary biomarkers as candidates for gingivitis and periodontitis, which are major oral health threats, affecting the gums. These need to be verified and validated for their potential use as differentiators of health, gingivitis and periodontitis status, before they are translated to chair-side for diagnostics and personalized monitoring. We aimed to measure 10 candidates using high sensitivity ELISAs in a well-controlled cohort of 127 individuals from three groups: periodontitis (60), gingivitis (31) and healthy (36). The statistical approaches included univariate statistical tests, receiver operating characteristic curves (ROC) with the corresponding Area Under the Curve (AUC) and Classification and Regression Tree (CART) analysis. The main outcomes were that the combination of multiple biomarker assays, rather than the use of single ones, can offer a predictive accuracy of > 90% for gingivitis versus health groups; and 100% for periodontitis versus health and periodontitis versus gingivitis groups. Furthermore, ratios of biomarkers MMP-8, MMP-9 and TIMP-1 were also proven to be powerful differentiating values compared to the single biomarkers.