Schulz J, et al. - In this study, researchers examined whether recombinant secreted frizzled-related protein 5 (sFRP5) improves periodontal status in human periodontitis using an epidemiological approach. In human serum from the Food Chain Plus cohort, they determined sFRP5 and wnt5a concentrations using ELISAs. In a nested case–control design, 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. Patients with periodontitis and tooth loss had significantly lower systemic sFRP5 serum levels than patients with periodontitis without tooth loss and matched controls. Patients with periodontitis without tooth loss and controls showed no significant differences in sFRP5 serum levels. Findings suggest a possible utility of sFRP5 as a novel biomarker for periodontitis severity.