Increased serum PCSK9 concentrations are associated with periodontal infection but do not correlate with LDL cholesterol concentration

Background: Periodontal disease increases the risk of atherothrombotic disease, and high concentrations of low density lipoprotein (LDL) cholesterol are considered to be involved: however, the underlying mechanisms are largely unknown. Recent studies demonstrated that proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a critical role in circulating LDL cholesterol concentrations. The aim of the present study is to analyze serum PCSK9 concentrations and their relation to lipoprotein concentrations in periodontitis patients. Methods: Sera were obtained from 40 periodontitis patients and 30 control subjects. PCSK9 concentrations, high-sensitivity C-reactive protein (hs-CRP), IL-6, TNF-alpha and Porphyromonas gingivalis antibodies were measured by ELISA, and lipid profiles were determined by a commercial laboratory. Results: Periodontitis patients demonstrated significantly higher serum antibody titer to P. gingivalis and hs-CRP concentrations than control subjects, suggesting infection with P. gingivalis and a systemic inflammatory response. PCSK9 concentrations in periodontitis patients were significantly higher than those in control subjects. However, the concentrations of total and LDL cholesterols were not significantly different between periodontitis patients and control subjects. Moreover, no correlations were observed between PCSK9 concentrations and lipid profiles. Conclusion: Periodontal infection upregulates PCSK9 production. However, further studies are required to elucidate how periodontal infection affects PCSK9 concentrations and subsequent lipid metabolism. (C) 2011 Elsevier B.V. All rights reserved.