MMP-8 and TIMP-1 are associated to periodontal inflammation in patients with rheumatoid arthritis under methotrexate immunosuppression - First results of a cross-sectional study.

BACKGROUND

Aim of this cross-sectional study was the investigation of associations between different rheumatoid arthritis (RA)-related blood parameters and periodontal condition as well as selected periodontal pathogenic bacteria in RA patients under methotrexate (MTX) immunosuppression.

METHODS

Periodontal probing depth (PPD), bleeding on probing (BOP) and clinical attachment loss (CAL) were assessed. Periodontal condition was classified into: no/mild and moderate or severe periodontitis (P). Prevalence of selected periodontal pathogenic bacteria and concentration of matrix metalloproteinase 8 (MMP-8) was assessed from the gingival crevicular fluid (GCF) using PCR and ELISA, respectively. Blood samples were analyzed for the concentration of selected rheumatoid parameters.

STATISTICAL ANALYSIS: t-test, Mann-Whitney-U-Test, exact Fisher tests or chi square test (p < 0.05).

RESULTS

Fifty-six patients (mean age 55.07 years, 34 P, 22 no P) were included. While prevalence of periodontal pathogenic bacteria was higher in P patients, no substantial association of bacteria with blood parameters was found. In periodontal diseased participants, MMP-8 concentration in GCF (6.22 ± 7.01 vs. 15.99 ± 13.49; p < 0.01) and blood (2.60 ± 3.57 vs. 5.52 ± 5.92; p < 0.01) was increased, while no correlation between GCF and blood was found (Spearman's rho: 0.175; p = 0.23). Furthermore, higher blood concentrations of MMP-8 and tissue inhibitor of MMP (TIMP-1) were detected in patients with increased periodontal inflammation (BOP positive, p < 0.01).

CONCLUSION

Periodontal inflammation appears associated to MMP-8 and TIMP-1 in blood. Thereby, clinical interaction between periodontal conditions, periodontal pathogenic bacteria and RA-related cytokines remain unclear.