Secreted frizzled-related protein 5 serum levels in human periodontitis—A nested case–control study

Aim: Recombinant secreted frizzled-related protein 5 (sFRP5) improved periodontal status in mice. Thus, this study aimed to investigate this finding in human periodontitis using an epidemiological approach. Materials and Methods: sFRP5 and wnt5a concentrations were determined in human serum from the Food Chain Plus cohort using ELISAs. A total of 128 patients with periodontitis and tooth loss and 245 patients with periodontitis without tooth loss were compared to 373 sex-, smoker-, age- and BMI-matched individuals in a nested case–control design. Results: Systemic sFRP5 serum levels were significantly lower in patients with periodontitis and tooth loss (2.5 [0.0–10.4] ng/ml, median [IQR]) compared to patients with periodontitis without tooth loss (6.0 [2.5–15.8] ng/ml, median [IQR], p = 0.04] and matched controls (7.0 [2.5–18.3] ng/ml, median [IQR], p = 0.02). No significant differences in sFRP5 serum levels were found among patients with periodontitis without tooth loss (6.0 [2.5–15.8] ng/ml, median [IQR]) and controls (3.1 [0.0–10.6] ng/ml, median [IQR], p = 0.06). Conclusions: sFRP5 might serve as a novel biomarker for periodontitis severity. Modulating the inflammatory background of severe forms of periodontitis, in the time of precision medicine, needs to be revealed in further studies.