PCSK9 and familial hypercholesterolemia: Polyphenol-rich black currant reduced hypercholesterolemia, hyperglycemia, and liver steatosis, and also prevented diet-induced metabolic disturbances through the modulation of proprotein convertase subtilisin/kexin type 9 (PCSK9)/low-density lipoprotein receptor (LDL-R) pathways.