Enhanced circulating PCSK9 concentration by berberine through SREBP-2 pathway in high fat diet-fed rats.

BACKGROUND: Berberine (BBR), a natural plant extract, has been shown to improve lipid metabolism. However, its effects on PCSK9, a key factor involving in the lipid metabolism, have not yet been evaluated in vivo. The aim of the present study was to investigate the effect of BBR on PCSK9 expression in high fat diet-fed (HFD) rats. METHODS: Thirty-two male Sprague Dawley (SD) rats were randomized into the four groups (n = 8): normal diet (Control), HFD, HFD + simvastatin (Sim, 2 mg/kg/d) and HDF + BBR (400 mg/kg/d) for 6 weeks. The following parameters were determined: 1) body weight; 2) serum lipid profile; 3) serum PCSK9 measured by enzyme-linked immuno sorbent assay (ELISA) ; 4) hepatic expressions of low-density lipoprotein receptor (LDLR), sterol regulatory element binding protein-2 (SREBP-2) and hepatocyte nuclear factor 1 (HNF1) were examined by real time quantitative polymerase chain reaction (RT-PCR) and western blotting analysis. RESULTS: Compared with HFD rats, Sim and BBR significantly reduced body weight gain and improved lipid profile (P < 0.05 respectively). In addition, either of drug treatment for 6 weeks could increase serum concentration of PCSK9 in HFD rats (P < 0.05). This enhanced PCSK9 expression was demonstrated to be associated with the up-regulation of hepatic expression of LDLR and SREBP-2 and the down-regulation of hepatic expression of HNF1 (P < 0.05 respectively). CONCLUSIONS: The data provided the first line of the evidence that BBR, similar to the Sim, could increase the expression of PCSK9 levels in HFD rats through SREBP-2 activation, suggesting that impacts of BBR on lipid profile may also be linked to SREBP-2 pathway.

RANTES gene G-403A polymorphism and coronary artery disease: a meta analysis of observational studies.

OBJECTIVE: The G-403A polymorphism in RANTES gene may be involved in the development of coronary artery disease (CAD) through increasing RANTES-mediated leukocyte trafficking and activation. However, studies investigating the relationship between G-403A polymorphism and CAD yielded contradictory and inconclusive results. In order to shed some light on these inconsistent findings, a meta analysis was performed to clarify the role of G-403A polymorphism of RANTES gene in the susceptibility of CAD. METHODS: A systemic literature search of PubMed and EMBASE was conducted from their inception to March 23, 2012, to retrieve related studies. In addition, Conference Proceedings Citation Index-Science was searched, authors of relevant studies were contacted, and reference lists of the included studies and their related citations in PubMed were reviewed for additional pertinent studies. RESULTS: A total of 8 eligible studies were identified, with a total of 4252 CAD cases and 2150 controls. There was no evidence of significant association between G-403A polymorphism and CAD risk in any genetic model or pairwise comparisons (additive model: OR = 1.046, 95% CI = 0.883-1.239, I(2) = 65.9%; recessive model: OR = 1.140, 95% CI = 0.774-1.678, I(2) = 53.1%; dominant model: OR = 1.000, 95% CI = 0.820-1.21), I(2) = 62.6%; AA vs GG: OR = 1.141, 95% CI = 0.734-1.773, I(2) = 61.2%; GA vs GG: OR = 0.993, 95% CI = 0.800-1.232, I(2) = 64.6%). Subgroup analysis and meta regression indicated that ethnicity and genotyping method accounted for the significant heterogeneity among studies. In the stratified analysis by ethnic group, G-403A polymorphism was found to be associated with increased CAD risk in Caucasian population whereas its protective role was observed in Asian population in some but not all comparisons. CONCLUSION: Data from the current meta-analysis do not support the existence of a relationship between G-403A polymorphism and the development of CAD, and large sample size study employing unified genotyping method is needed to further evaluate the influence of G-403A polymorphism on susceptibility of CAD.