Association of the HNF1A polymorphisms and serum lipid traits, the risk of coronary artery disease and ischemic stroke.

BACKGROUND: Hepatocyte nuclear factor-1α gene (HNF1A) single nucleotide polymorphisms (SNPs) have been associated with serum lipid traits in several previous genome-wide association studies. However, little is known about such associations in the Chinese populations. The present study aimed to determine the association of the HNF1A rs1169288, rs2259820, rs2464196 and rs2650000 SNPs and serum lipid traits, the risk of coronary artery disease (CAD) and ischemic stroke (IS). METHODS: The genotypes of the four SNPs in 562 CAD and 521 IS patients, as well as 594 healthy controls, were detected using the Snapshot technology. RESULTS: The genotype and allele distribution of the four SNPs was not different between controls and CAD or IS patients (p > 0.05 for all). rs1169288, rs2259820 and rs2464196 SNPs were significantly associated with serum lipid levels in both controls and CAD patients (p < 0.004-0.009). rs2259820 and rs2464196 SNPs were significantly associated with a lower risk of CAD [odds ratio (OR) = 0.64, 95% confidence interval (CI) = 0.44-0.91, p = 0.015 and OR =0.62, 95% CI = 0.43-0.89, p = 0.010, respectively]. Significant linkage disequilibrium was noted among the four SNPs (r2  > 0.5, D' > 0.8). The haplotype of rs1169288A-rs2259820C-rs2464196G-rs2650000A was associated with an increased risk of CAD (OR =1.95, 95% CI: 1.13-3.37, p = 0.015). Interactions of SNP-SNP (rs1169288-rs2464196-rs2650000) and haplotype-environment on the risk of CAD (A-C-G-A-smoking) or IS (A-C-G-A-sex and A-T-A-C-alcohol consumption) were also observed among these SNPs. CONCLUSIONS: These findings suggest that the HNF1A polymorphisms may be the genetic risk factors for CAD and IS.

Effect of atorvastatin on SR-BI expression and HDL-induced cholesterol efflux in adipocytes of hypercholesterolemic rabbits.

BACKGROUND: Adipose tissue contains a large amount of cholesterol and performs a buffer function for circulating cholesterol. Scavenger receptor class B type I (SR-BI) might play a significant role in adipocytes cholesterol metabolism through mediation of cholesterol efflux. We evaluated the effect of atorvastatin on SR-BI expression and HDL-induced cholesterol efflux in adipocytes from hypercholesterolemic rabbits. METHODS: Sixteen rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into 2 groups: (1) maintained on a high cholesterol diet for 6 weeks (n=8); (2) the same cholesterol diet plus atorvastatin (2.5 mg/kg/day) for 6 weeks (n=8). Control group (n=5) was fed with normal diet for 14 weeks. Subcutaneous adipose was collected for adipocyte culture. Reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate adipocytes SR-BI mRNA expression. Cholesterol efflux rate was determined through measuring release of radioactivity from (3)H-cholesterol prelabeled cells into medium containing high-density lipoprotein (HDL). The direct effect of atorvastatin on SR-BI mRNA expression in primary rabbit adipocytes was assayed. RESULTS: High-cholesterol diet decreased SR-BI mRNA expression and reduced HDL-induced cholesterol efflux rate in adipocytes. Six weeks of atorvastatin treatment significantly enhanced the cholesterol efflux from adipocytes, which was related to the increased mRNA expression of SR-BI (r=0.58, P<0.05). Adipocytes SR-BI mRNA expression were negatively correlated with the serum total cholesterol levels at the end of the study (r=-0.46, P<0.05). Atorvastatin dose-dependently stimulated SR-BI mRNA expression in cultured adipocytes. CONCLUSION: Atorvastatin can up-regulate SR-BI mRNA expression and promote the HDL-induced cholesterol efflux in adipocytes from hypercholesterolemic rabbits possibly through lowering serum cholesterol levels and directly stimulating SR-BI mRNA expression.

[Atorvastatin reduces the expression of COX-2 mRNA in peripheral blood monocytes in patients with acute myocardial infarction and modulates the early inflammatory response].

OBJECTIVE: To measure the effect of atorvastatin on COX-2 expression in monocytes in patients with acute myocardial infarction (AMI). METHODS: Forty patients with AMI (AMI group) and 18 patients with stable coronary heart disease (control group) were enrolled, and patients with AMI were randomly given routine therapy (n = 20) and routine therapy plus atorvastatin (20 mg/day, n = 20) for a week. Peripheral blood monocytes for each participant including patients with AMI were isolated and cultured for 24 hours. During the culture, monocytes in patients with pretreatment AMI were incubated with celecoxib in different concentration (0, 0.1, 1 and 10 micromol/L). COX-2 mRNA expression in monocytes was measured by reverse transcription polymerase chain reaction (RT-PCR); concentrations of interleukin-6 (IL-6) in supernatant from monocytes and plasma hs-CRP levels were measured by using enzyme-linked immunosorbent assay (ELISA). RESULTS: COX-2 expression in monocytes in patients with AMI (0.92 +/- 0.13) was significantly higher than that in the control subjects (0.19 +/- 0.08), and decreased by 66% after atorvastatin (compared with that on routine therapy, P < 0.05); IL-6 secretions of monocytes in the AMI group (204.8 +/- 45.6 ng/L) increased dramatically compared with those in the control group (40.9 +/- 1.2 ng/L, P < 0.05), and reduced dramatically by 58% when incubated with 10 micromol/L celecoxib (P < 0.05) in a concentration-dependent manner; plasma levels of CRP in the AMI group (43.3 +/- 14.9 mg/L) significantly increased compared with those in the control group (1.7 +/- 0.8 mg/L), and reduced by 62% after atorvastatin (compared with those in the routine therapy group, P < 0.05). COX-2 expression in monocytes in the AMI group was positively correlated with both secretions of IL-6 and plasma level of CRP (r = 0.636 and 0.662, respectively, both P < 0.05). CONCLUSIONS: There is an inflammatory activation in peripheral blood monocytes in patients with early AMI, and the monocytes-derived COX-2 may play an important role in promoting early inflammatory process. Atorvastatin may decrease COX-2 expression in peripheral blood monocytes in patients with AMI and cyclooxygenase-dependent pathway might be correlated with the anti-inflammation mechanism of statin.

Association of variants in CELSR2-PSRC1-SORT1 with risk of serum lipid traits, coronary artery disease and ischemic stroke.

Recent genome-wide association studies (GWAS) have identified genetic variants associated with coronary artery disease (CAD), ischemic stroke (IS) and serum lipid traits in different ethnic groups. Some loci were found to affect the risk of CAD and IS. However, there were no data in the southern Chinese populations. Our study was to assess the association of CELSR2-PSRC1-SORT1 rs599839, rs464218 and rs6698443 SNPs and serum lipid levels and the risk of CAD and IS. The genotypes of 3 SNPs were detected in 561 CAD and 527 IS patients, and in 590 healthy controls. The genotypic and allelic frequencies of the rs599839 SNP were different between the controls and IS patients (P < 0.05). The minor G alleles of rs599839 and rs464218 SNPs were associated with higher high-density lipoprotein cholesterol concentrations in CAD and IS patients (P < 0.05); respectively. No association was found between the SNPs of rs599839, rs464218 and rs6698843 at the CELSR2-PSRC1-SORT1 and the risk of CAD or IS. These results will be replicated in the other Chinese populations.

Polymorphisms in the GCKR are associated with serum lipid traits, the risk of coronary artery disease and ischemic stroke.

The present study was to determine the association of two single nucleotide polymorphisms (SNPs) in the glucokinase regulator gene (GCKR) and serum lipid levels, and the risk of coronary artery disease (CAD) and ischemic stroke (IS). Genotypes of the GCKR rs1260326 and rs8179206 in 1736 unrelated subjects (CAD, 584; IS, 555; and healthy controls; 597) were determined by the Snapshot technology platform. The genotypic and allelic frequencies of rs1260326 and rs8179206 were not different among the three groups (P > 0.05). The subjects with rs1260326TT genotype had higher serum low-density lipoprotein cholesterol (LDL-C) levels in controls, and higher triglyceride (TG) levels in CAD patients than the subjects with CC and CT genotypes after adjustment for age, sex, body mass index, blood pressure, alcohol consumption, and cigarette smoking (P < 0.05). The rs1260326TT genotype was also associated with decreased risk of IS in females (OR = 0.37, 95% CI: 0.18-0.76, P = 0.007). The present study shows that the GCKR rs1260326TT genotype is associated with high LDL-C in controls, high TG levels in CAD patients, and a decreased risk of IS in females.

[Study on defibrinogenasing enhancing the thrombolytic effect of urokinase on acute myocardial infarction].

OBJECTIVE: To investigate the thrombolytic effects and the security of combined therapy of defibrinogenase (DEF) and lower dose urokinase (UK) on patients with acute myocardial infarction (AMI). METHODS: Forty-five patients with AMI within 6 hours from the onset were divided into two groups, the combined therapy group (UK+DEF group, n=23) and the full dose UK group (UK group, n =22). The dosage of the UK in UK+DEF group was only the half of the full dos e UK group. In UK+DEF group, intravenous injection of 5 U DEF was preceded with intravenous infusion of UK, and after that, 5 U of DEF was infused intravenously in three separate times. Aspirin was prescribed for all patients. Coronary reperfusion was evaluated according to clinical criteria. The complication of bleeding was noted. Plasma fibrinogen (Fg) and D-dimer levels were determined before and after thrombolytic therapy. RESULTS: The age, body weight, time from onset, reperfusion rate, reinfarction rate, bleeding complications and the mortality during hospitalization were similar in both groups (P>0.05), and no severe bleeding was found. The reperfusion rate of UK+DEF group (69.56 percent) was comparable with that of UK group (68.18 percent), P>0.05. While the time to reperfusion of UK+DEF group was markedly shorten than that of UK group, it was (62.08+/-32.40) minutes vs. (80.00+/-39.14) minutes respectively (P<0.01). The plasma levels of D-dimer were similar and were elevated at the 6 hours after the beginning of thrombolytic therapy both in two groups (P<0.05). The plasma Fg level was declined obviously in UK+DEF group with a decrease in 58.46 percent, while it was slightly declined in UK group with a 16.78 percent decrease in percentage compared to those levels of pre-thrombolysis. CONCLUSION: The combination of DEF can enhance the thrombo lytic efficacy of UK, and can accelerate the lysis of coronary thrombus. The effect and the security of combination therapy are comparable to the full dose UK therapy.

Effect of the anti-oxidant probucol on soluble thrombomodulin (sTM) in hypercholesterolemic rabbits.

INTRODUCTION: Thrombomodulin is an integral endothelial cell membrane protein, exists not only on the surface of endothelial cells but also as soluble fragments circulating in plasma. Probucol has anti-oxidant properties as well as cholesterol-lowering effects and may affect soluble thrombomodulin (sTM). METHODS: Sixteen rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into two groups: (1) high-cholesterol group (n=8): maintained high-cholesterol diet; (2) probucol group (n=8): the same diet plus probucol for 6 weeks. Control group (n=8) was fed with normal diet for 14 weeks. The levels of sTM and oxidized low-density lipoprotein (OX-LDL) were measured using ELISA. RESULTS: There were atherosclerotic lesions in aortas and intimal thickness significantly increased in high-cholesterol group. Probucol significantly reduced the lesion area (56.4%+/-9.8% vs 82.5%+/-10.5%) and decreased the intimal thickness (44.65+/-7.25 mum vs 72.21+/-8.32) as compared with high-cholesterol group, all P<0.01. Probucol decreased the level of OX-LDL and sTM as compared with high-cholesterol group, all P<0.05. CONCLUSIONS: Probucol retarded the plaques formation may relate to decrease plasma OX-LDL and sTM concentration, which may improve endothelial function in hypercholesterolemic rabbit.

Effect of probucol on HDL metabolism and class B type I scavenger receptor (SR-BI) expression in the liver of hypercholesterolemic rabbits.

BACKGROUND: Scavenger receptor class B type I (SR-BI) is a major receptor for high-density lipoproteins (HDL) in the liver. Overexpression of SR-BI attenuated experimental atherosclerosis in murine models, concomitant with a reduction in plasma HDL-cholesterol levels. Probucol is known to be a potent hypolipidemic drug to regress xanthoma formation and carotid atherosclerosis in conjunction with a marked reduction in HDL-cholesterol levels. However, the mechanism by which probucol affects atherosclerosis is not completely understood, and the effect of probucol on the expression of SR-BI was controversial. The aim of this study was to know the effect of probucol on HDL metabolism and SR-BI expression in the liver. METHODS: Sixteen rabbits fed with high cholesterol diet for 8 weeks were randomly divided into two groups: (1) high cholesterol group (n = 8): maintained high cholesterol diet for 6 weeks; (2) probucol group (n = 8): the same cholesterol diet plus 1% probucol for 6 weeks. Control group (n = 8) was fed with normal diet for 14 weeks. The classical in situ two steps perfusion of the liver with collagenase IV was used to isolate the parenchymal hepatocytes. The selective uptake of HDL by hepatocytes was performed using the double radiolabelled HDL. Immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR) were used to evaluate SR-BI expression in the liver. RESULTS: Compared with control group, rabbits fed with high cholesterol diet showed higher levels of serum total cholesterol (TC), low-density lipoprotein (LDL) cholesterol and HDL-C, all of which were significantly reduced by probucol treatment. The selective uptake of HDL CEs in probucol group (249.68 +/- 60.13 ng/mg cell protein) was about two folds higher as compared with the control group (122.47 +/- 54.06 ng/mg cell protein, P < 0.01) and high cholesterol group (104.92 +/- 47.91 ng/mg cell protein, P < 0.01), but it could not be reproduced in vitro. The expression of SR-BI were significantly decreased in the high cholesterol group (0.48 +/- 0.06) as compared with control group (0.65 +/- 0.06, P < 0.01). Probucol increased SR-BI expression (0.68 +/- 0.06, P < 0.01) as compared with high cholesterol group. The expression of SR-BI was positively associated with the selective CEs uptake (r = 0.47, P = 0.032). CONCLUSIONS: Probucol up-regulates SR-BI expression and enhance the uptake of HDL CEs by hepatocytes, which may help us to understand the anti-atherogenic properties and the HDL-C-lowering effect of probucol.

Probucol up-regulates paraoxonase 1 expression in hepatocytes of hypercholesterolemic rabbits.

Paraoxonase 1 (PON1), an HDL-associated enzyme, has anti-oxidative property. Probucol, a hydrophobic antioxidant drug, inhibits progression of atherosclerosis and post-angioplasty restenosis. However, the mechanism by which probucol affects atherosclerosis is not completely understood. Sixteen rabbits fed with high cholesterol diet for 8 weeks were randomly divided into two groups: (1) starch group (n = 8): maintained high cholesterol diet plus starch (500 mg/kg/d) for 6 weeks; (2) probucol group (n = 8): the same cholesterol diet plus probucol (500 mg/kg/d) for 6 weeks. Control group (n = 8) was fed with normal diet for 14 weeks. The classic in-situ two-step perfusion of the liver with collagenase IV was used to isolate the parenchymal hepatocytes. The total activity of superoxide dismutase (SOD) and malondialdehyde (MDA) and PON1 concentrations in serum were measured after 0, 8, and 14 weeks of feeding. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of PON1. Compared with control group, rabbits fed with high cholesterol diet showed higher levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), all of which were significantly reduced by probucol. Probucol significantly decreased the MDA concentration but was ineffective on SOD activity. High cholesterol diet decreased serum PON1 concentration and down-regulated PON1 mRNA expression in hepatocytes. Probucol significantly increased serum PON1 level and up-regulated the mRNA expression of PON1 as compared with starch group (0.65 +/- 0.06 versus 0.46 +/- 0.05, P = 0.001). The PON1 concentration is negatively associated with MDA concentration (r = -0.86, P = 0.003) but not with the level of HDL-C. In conclusion, probucol decreased MDA concentration, and increased PON1 serum level as well as mRNA expression in hepatocytes, which may help us to understand its antioxidant and anti-atherogenic effects.

Effect of atorvastatin on tumor necrosis factor alpha serum concentration and mRNA expression of adipose in hypercholesterolemic rabbits.

Tumor necrosis factor alpha (TNFalpha) is an inflammatory cytokine involved in atherogenesis. Adipose tissue is an important source of endogenous TNFalpha production. The aim of this study was to evaluate the effect of atorvastatin on TNFalpha serum concentration and mRNA expressions of subcutaneous adipose in hypercholesterolemic rabbits. Sixteen rabbits fed with a high-cholesterol diet for 8 weeks were randomly divided into 2 groups: (1) the high-cholesterol group (n=8) was maintained on a high-cholesterol diet for 6 weeks; (2) the atorvastatin group (n=8) had the same high-cholesterol diet plus atorvastatin (2.5 mg/kg/d) for 6 weeks. A control group (n=5) was fed with a normal diet for 14 weeks. Subcutaneous adipose was collected for mRNA analysis. Additionally, the direct effect of atorvastatin on TNFalpha release and mRNA expression was assayed in primary rabbit adipocytes. TNFalpha levels in serum and adipocyte culture supernatant were measured by ELISA. RT-PCR was used to evaluate TNFalpha mRNA expression in adipose and adipocytes. Serum TNFalpha concentration was significantly associated with serum total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) (both P<0.01). Compared with the control group, rabbits fed with a high-cholesterol diet showed higher levels of TNFalpha serum concentration and mRNA expression of adipose, both of which were significantly reduced by atorvastatin treatment (both P<0.05). TNFalpha mRNA expressions of adipose were significantly correlated with circulating TNFalpha levels among the 3 groups (r=0.51, P<0.05). Atorvastatin dose-dependently inhibited lipopolysaccharide (LPS)-induced TNFalpha secretion and mRNA expression in cultured adipocytes. In conclusion, atorvastatin can directly inhibit TNFalpha expression and secretion in adipocytes. Atorvastatin reduced TNFalpha serum concentration in hypercholesterolemic rabbits, which might be because of its cholesterol-lowering effect and direct inhibition of TNFalpha expression in adipose.