Association of the salivary triggering receptor expressed on myeloid cells/its ligand peptidoglycan recognition protein 1 axis with oral inflammation in kidney disease

Background: Triggering receptor expressed on myeloid cells (TREM-1) is a cellsurface receptor involved in amplification of inflammatory response to bacterial infections, along with its ligand peptidoglycan recognition protein 1 (PGLYRP1). TREM-1 is shed by matrix metalloproteinases (MMPs) to its soluble (s) form. The aim of the study is to investigate association of sTREM-1 and PGLYRP1 with oral inflammatory burden among patients with chronic kidney disease (CKD) at predialysis and posttransplantation stages. Methods: One hundred forty-four patients with CKD were examined at predialysis, and oral infection foci were treated prior to kidney transplantation. Fifty-three patients were available for follow-up after transplantation. Oral inflammatory burden was assessed by the Periodontal Inflammatory Burden Index (PIBI) and Total Dental Index. sTREM-1, PGLYRP1, and interleukin (IL)-1 beta were measured in saliva by enzyme-linked immunosorbent assay, and MMP-8 was measured by immunofluorometric assay. Results: In the predialysis stage, sTREM-1 and PGLYRP1 were positively associated with IL-1 beta, MMP-8, and PIBI. More specifically, patients with deeper probing depth (PD) (at least two sites with >= 6 mm) had higher concentrations of salivary sTREM-1 and PGLYRP1 compared with those with shallower PD. Higher concentrations of PGLYRP1 and IL-1 beta were associated with a higher number of teeth (> 25). On follow-up, higher PGLYRP1 and sTREM-1 were associated with one or more sites with >= 4 mm PD. Conclusions: sTREM-1 and PGLYRP1 are elevated in patients with CKD with poor oral health and positively correlate with number of active periodontal pockets after oral infection therapy. Moreover, they positively correlate with MMP-8 and IL-1 beta Hence, the salivary sTREM-1/PGLYRP1 axis could be useful as a diagnostic marker for oral infection within patients with CKD.