A point-of-care test of active matrix metalloproteinase-8 predicts triggering receptor expressed on myeloid cells-1 levels in saliva

Background This cross-sectional study aims to investigate if a point-of-care (PoC) test of active matrix metalloproteinase-8 (aMMP-8) predicts levels of inflammation amplifier triggering receptor expressed on myeloid cells-1 (TREM-1) and its putative ligand the neutrophil peptidoglycan recognition protein 1 (PGLYRP1) in saliva. Methods Forty-seven adolescents, aged 15 to 17 years, were tested with aMMP-8 PoC test, which was followed by a full-mouth clinical examination of the assessment of periodontal, mucosal, and oral health. TREM-1 and PGLYRP1 levels were analyzed by ELISA. The immunofluorometric assay (IFMA) specific for aMMP-8 was used as the reference method. Results Fourteen saliva samples out of a total of 47 showed positivity for aMMP-8 PoC test. Both the TREM-1 and the aMMP-8 (IFMA) levels were significantly elevated among the aMMP-8 PoC test positives compared with the PoC test negatives (P < 0.05). Moreover, aMMP-8 levels assessed by IFMA showed a strong positive correlation with TREM-1 levels in saliva (r = 0.777, P < 0.001). The number of sites with a probing depth of >= 4 mm was significantly lower among the adolescents that had a negative aMMP-8 PoC test result, and TREM-1 levels < 75 pg/mL (P < 0.05). In contrast, adolescents with a positive aMMP-8 PoC test result (i.e., elevated aMMP-8 levels) together with elevated TREM-1 levels had a significantly higher number of periodontal pockets with >= 4 mm (P < 0.001). Conclusion The present study validated usability of aMMP-8 PoC test for predicting proinflammatory salivary profile and periodontal health status in adolescents.