Salivary Biomarkers of Oral Inflammation Are Associated With Cardiovascular Events and Death Among Kidney Transplant Patients

Association of salivary TREM-1 and PGLYRP1 inflammatory markers with non-communicable diseases

AIM

Triggering receptor expressed on myeloid cells 1 (TREM-1) and peptidoglycan recognition protein 1 (PGLYRP1) are elevated in biofluids in the presence of various inflammatory conditions. This cross-sectional study aimed to evaluate the effect of age, sex, smoking and different oral and systemic non-communicable diseases on the levels of TREM-1 and PGLYRP1 in saliva.

MATERIALS AND METHODS

In total, 445 individuals (mean age 48.7 ± 16.9 years, female:male 51%:49%) were included. All provided self-reported information on smoking and systemic diseases and whole stimulated saliva. Periodontal and cariological parameters were recorded. Salivary levels of TREM-1, PGLYRP1 and total protein were measured using commercially available assays.

RESULTS

Salivary TREM-1 levels were significantly higher in stages III-IV periodontitis compared to other periodontal diagnoses (p < .05). Smoking, bleeding on probing (BOP), percentage of pockets ≥4 mm and the number of manifest caries were associated with TREM-1 (p < .05), while sex, BOP, number of manifest caries and muscle and joint diseases were associated with PGLYRP1 (p < .05).

CONCLUSIONS

Salivary TREM-1 is associated with periodontitis and caries, while PGLYRP1 is associated with gingival inflammation and caries. Additionally, TREM-1 levels are modified by smoking, while PGLYRP1 is modified by sex and muscle and joint diseases. TREM-1 and PGLYRP1 in saliva could serve as potential biomarkers for detecting and monitoring non-communicable diseases.

Expressions of Peptidoglycan Recognition Protein 1, Neuron Towards Axon Guidance Factor-1 and miR-142-3p and Their Correlations in Patients with Rheumatoid Arthritis

Purpose

We aimed to explore the expressions of peptidoglycan recognition protein 1 (PGLYRP-1), neuron towards axon guidance factor-1 (Netrin-1) and miR-142-3p and their correlations in patients with rheumatoid arthritis.

Patients and Methods

Sixty patients with rheumatoid arthritis treated from January 2022 to January 2023 were enrolled as a rheumatoid group, 30 patients with osteoarthritis were selected as an osteoarthritis group, and 30 healthy volunteers were recruited as a control group. The enzyme-linked immunosorbent assay, Western blotting and reverse transcriptase-polymerase chain reaction were employed to measure the expressions of PGLYRP-1, Netrin-1 and miR-142-3p, respectively. The correlations among PGLYRP-1, Netrin-1 and miR-142-3p expressions in patients with rheumatoid arthritis were analyzed.

Results

In patients with rheumatoid arthritis, PGLYRP-1 expression was negatively correlated with Netrin-1 expression (r=-0.570, P=0.001) but positively correlated with miR-142-3p expression (r=0.599, P=0.001), and a negative correlation was found between Netrin-1 and miR-142-3p expressions (r=-0.468, P=0.001). The combined detection of PGLYRP-1, Netrin-1 and miR-142-3p was more sensitive and less specific for predicting the prognosis of patients with rheumatoid arthritis than the measurement of a single marker (P<0.05).

Conclusion

The combined measurement of PGLYRP-1, Netrin-1 and miR-142-3p has a predictive value for the prognosis of patients with rheumatoid arthritis.

Association of peptidoglycan recognition protein 1 to post-myocardial infarction and periodontal inflammation: A subgroup report from the PAROKRANK (Periodontal Disease and the Relation to Myocardial Infarction) study

BACKGROUND

Peptidoglycan recognition protein 1 (PGLYRP1) is an antimicrobial and proinflammatory innate immunity protein activated during infections. We aimed to investigate whether PGYLRP1 and associated molecules of the immune response in saliva is a cumulative outcome result of both MI and periodontal inflammation.

METHODS AND RESULTS

Two hundred patients with MI and another 200 matched non-MI controls were included. A full-mouthexamination was conducted to assess periodontal inflammation and collection of stimulated saliva was performed 6 to 10 weeks after the first MI. PGLYRP1, triggering receptor expressed on myeloid cells 1 (TREM-1), interleukin-1 beta (IL-1β) were analyzed by ELISA. Matrix metalloproteinase (MMP)-8 levels were determined by IFMA. Compared to controls, MI patients showed higher salivary PGLYRP1, but not TREM-1 levels. The difference in PGLYRP1 levels remained after adjustment for covariates. In MI patients, the PGLYRP1 levels positively correlated with BOP and PPD 4 to 5 mm. Among non-MI subjects, the levels of PGLYRP1 correlated positively and significantly with BOP and total PPD. Salivary PGLYRP1 concentrations also showed strong positive correlations with levels of TREM-1, IL-1β and MMP-8. In multivariate linear regression analysis, in MI patients, BOP and former smokingstatus displayed an association with salivary PGLYRP1 concentration.

CONCLUSION

MI patients showed higher salivary PGLYRP1 levels than healthy controls, also after adjusting for smoking, sex, age and periodontal health status. Salivary levels of PGLYRP1 may reflect the overall inflammatory burden to chronic bacterial exposure, possibly underpinning the observed associations between periodontitis and exposure with MI.

Elevated serum TREM-1 is associated with periodontitis and disease activity in rheumatoid arthritis

The triggering receptor expressed on myeloid cells 1 (TREM-1) and peptidoglycan recognition protein 1 (PGLYRP1) are involved in the propagation of inflammatory responses. This study investigated whether serum levels of TREM-1 and PGLYRP1 correlate with periodontitis in rheumatoid arthritis (RA) patients. A total of 154 non-smoking participants with RA (n = 55, F/M: 41/14), Behçet´s disease (BD, n = 41, F/M: 30/11) and healthy controls (HC, n = 58, F/M: 40/18) were recruited. Serum and saliva were collected, the 28-joint disease activity score (DAS-28) was calculated and dental/periodontal measurements were recorded. Serum TREM-1 and PGLYRP1 levels were measured by ELISA and salivary bacterial DNA counts by quantitative polymerase chain reaction. TREM-1 and PGLYRP1 levels were higher in RA (166.3 ± 94.3; 155.5 ± 226.9 pg/ml) than BD (102.3 ± 42.8; 52.5 ± 26.3 pg/ml) and HCs (89.8 ± 55.7; 67.4 ± 37.3 pg/ml) (p < 0.05). In RA, periodontitis was associated with increased TREM-1 and PGLYRP1 levels (p < 0.05), yet in patients under methotrexate TREM-1 levels were lower. TREM-1 correlated with C-reactive protein (CRP) levels, DAS-28 and erythrocyte sedimentation rate, whereas PGLYRP1 positively correlated with CRP. RA patients displayed 3.5-fold higher salivary bacterial DNA counts than HCs. Increased serum TREM-1 levels correlated with PGLYRP1, CRP and DAS-28-ESR in RA patients with periodontitis.