Serum Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) is Independently Associated with Insulin Resistance, Triglycerides, Lipoprotein(a) Levels but not Low-Density Lipoprotein Cholesterol Levels in a General Population

Aim: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been identified as an important regulator of low-density lipoprotein (LDL) receptor processing. Evolocumab and alirocumab are PCSK9 inhibitors; however, little is known about the association between PCSK9 levels and lipid profiles in a general population. Because PCSK9 inhibitors have LDL-C lowering effects, we investigated whether there is a positive correlation between serum PCSK9 levels and LDL-C or lipoprotein(a) [Lp(a)]. Methods: In Uku town, 674 residents (mean age; 69.2±8.3 years) received health check-ups. The participants underwent a physical examination and blood tests, including PCSK9 and Lp(a). Serum PCSK9 and Lp(a) were measured by ELISA and Latex methods, respectively. HOMA-IR was calculated by fasting plasma glucose×insulin levels/405. Results: The mean (range) of PCSK9 and Lp(a) were 211.2 (49-601) ng/mL and 60 (1-107) mg/dL, respectively. Because of a skewed distribution, the log-transformed values were used. With univariate linear regression analysis, PCSK9 levels were associated with Lp(a) (p=0.028), triglycerides (p＜0.001), and HOMA-IR (p＜0.001), but not with LDL-C (p=0.138) levels. Multiple stepwise regression analysis revealed that serum PCSK9 levels were independently associated with triglycerides (p＜0.001), Lp(a) (p=0.033) and HOMA-IR (p=0.041). Conclusions: PCSK-9 is independently associated with triglycerides, Lp(a) levels, and HOMA-IR, but not LDL-C, in a relatively large general population sample.