Positive correlation between plasma PCSK9 and tissue factors levels in patients with angiographically diagnosed coronary artery disease and diabetes mellitus

BACKGROUND: Pro-protein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that influences plasma levels of low-density lipoprotein cholesterol (LDL-C). Both oxidized LDL and tissue factor (TF) contributed to the development of prothrombotic state. The present study aims to explore the relationship between plasma level of PCSK9 and that of TF in patient with coronary artery disease (CAD). METHODS: From July 2013 to March 2014, we enrolled 197 consecutive patients who underwent coronary angiography because of suspected CAD at Beijing Anzhen Hospital in this study. All patients had no history of using lipid-lowering medication. Of these 197 patients (131 male and 66 female, mean age 56.9 ± 11.8 years), 81 had angiographically diagnosed CAD. Clinical data were collected. Plasma PCSK9 and TF were measured using enzyme-linked immunosorbent assay (ELISA). Levels of plasma PCSK9 and TF were compared and their correlation analyzed among different patient groups. RESULTS: Both plasma levels of PCSK9 (279.8 ± 60.4 µg/L vs. 216.5 ± 45.3 µg/L, P < 0.01) and TF (156.4 ± 26.6 µg/mL vs. 112.1 ± 38.3 µg/L, P < 0.01) were significantly higher in patients with CAD, as compared with those without CAD. Correlation analysis showed plasma level of PCSK9 was significantly correlated with that of TF in both patients with and without CAD. However, multivariate regression analysis after adjustment for age, gender, smoking, alcohol, hypertension and hyperlipidemia showed that only in CAD patients with type 2 diabetes mellitus, there was significant positive correlation between plasma levels of PCSK9 and TF (β = 0.353, P < 0.01). CONCLUSIONS: The plasma level of PCSK9 is independently and positively associated with that of TF in CAD patients with diabetes mellitus, but not in those without diabetes mellitus. Further study is needed to investigate the underlying mechanism.