Background: The purpose of this study was to evaluate the effects of concentrations of proprotein convertase subtilisin/kexin type 9 (PCSK9) and low-density lipoprotein (LDL) cholesterol by the mammalian target of rapamycin (mTOR) inhibitor everolimus and their effects on genetic polymorphisms in the PCSK9 and mTORC1 genes in 53 renal transplant recipients.
Methods: Prior to and on day 15 after everolimus administration, the concentrations of everolimus in blood and PCSK9 and LDL cholesterol in plasma were evaluated. Additionally, mTORC1 (rs2536T>C and rs2295080T>G) and PCSK9 (rs505151G>A, rs562556G>A, and rs11593680C>T) polymorphisms were analyzed.
Results: Mean PCSK9 plasma concentrations on day 15 after everolimus treatment were significantly higher than those before treatment (295 versus 214 ng/mL, respectively; p = 0.004). Significant correlations between the area under the blood concentration-time curves (AUC)0-12 on day 15 of everolimus treatment and the change rate in PCSK9 concentrations were found (r = 0.316, p = 0.021). However, there were no significant correlations between the change rate in PCSK9 and LDL cholesterol concentrations. The change rate in PCSK9 concentrations by everolimus treatment was significantly greater in patients with the mTORC1 rs2295080G allele than the T/T genotype (p = 0.006); however, there were no significant differences between PCSK9 rs505151G>A and rs11583680C>T genotypes. In multivariate analyses, patients with mTORC1 rs2295080G (p = 0.010), higher everolimus AUC0-12 (p = 0.006), and female sex (p = 0.029) showed higher change rates of PCSK9 following everolimus therapy.
Conclusions: Administration of everolimus significantly elevated plasma PCSK9 concentrations, potentially causing everolimus-induced hyperlipidemia.
Keywords: Everolimus; Low-density lipoprotein cholesterol; Mammalian target of rapamycin complex 1; Polymorphism; Proprotein convertase subtilisin/kexin type 9.