PCSK9 and metabolic syndrome: Currently, the existing pharmaceuticals which target on lowering LDL-C and TG level and on elevating HDL-C level, such as statins, fibrates, proprotein convertase subtilisin kexin 9 (PCSK9) inhibitors, cholesteryl ester transfer protein (CETP) inhibitors and fish oil, have been utilized alone or in various combinations to treat dyslipidemia [15–18].