OBJECTIVETo investigate the short- and long-term effects of Xuezhikang (XZK), an extract of cholestin, on proprotein convertase subtilisin/kexin type 9 (PCSK9) level.

METHODSThirty rats were randomly divided into three groups and were given saline, XZK 1,200 mg/kg or lovastatin 10 mg/kg respectively by daily gavage for 3 days (n=10 for each). Sixteen patients without previous lipid-lowering drug treatment for dyslipidemia received XZK 1,200 mg daily for 8 weeks. Fasting blood samples and liver tissue were collected at day 3 for rats, while the blood samples were obtained at baseline and week 8 from patients. The serum PCSK9 and lipid profile were measured. The expression of hepatic low density lipoprotein (LDL) receptor and sterol regulatory element binding protein 2 (SREBP-2) were measured by real time-PCR.

RESULTSPCSK9 levels in rats were significantly increased in the XZK and lovastatin groups (P=0.002, P=0.003 vs. control) at day 3, while no significant differences were found in the levels of lipid parameters. PCSK9 levels in patients increased by 34% (P=0.006 vs. baseline) accompanied by total cholesterol and LDL-cholesterol decreased by 22% and 28% P=0.001, P=0.002 vs. baseline). The hepatic mRNA levels of LDL-receptor and SREBP-2 were significantly increased in the XZK and lovastatin groups.

CONCLUSIONXZK has significant impact on PCSK9 in a short- and long-term manner in both rats and humans. Moreover, the data indicated that as lovastatin, XZK increased PCSK9 levels through SREBP-2 pathway.