Apolipoprotein E genotype and plasma levels in coronary artery disease. A case-control study in the Italian population.

OBJECTIVES: To investigate the role of the apolipoprotein B and apolipoprotein E polymorphisms in coronary artery disease (CAD) susceptibility in the Italian population and their relation to plasma lipid and apolipoprotein levels. METHODS: APOB (APOB Xbal, EcoRI, Ins/Del), and APOE (APOE Cfol) polymorphisms were analyzed in 150 male CAD patients and 110 matched controls. In the same subjects plasma lipid, apoB, and apoE levels were measured. RESULTS: No differences in the distribution of the APOB polymorphisms were observed between patients and controls. Among patients the number of e*4-carriers was significantly higher than in controls. e*4-carriers were more frequent among the hypertensive patients and had a higher systolic blood pressure (p = 0.007) than the non-e*4 carriers. The APOB Xbal polymorphism was found to influence the distribution of HDL-cholesterol. Patients showed significantly lower levels of apoE (39.29 mg/L) than controls (54.32 mg/dL) and the lowest concentrations were associated to the E4/E3 and E4/E4 genotypes. CONCLUSION: Quantitative data are consistent with the hypothesis that apoE has an anti-atherosclerotic role and suggest that the apoE quantitation could be a useful parameter for defining cardiovascular risk. e*4 allele appears to be a risk factor for CAD in the Italian population and could act by its association with low apoE levels.     

CETP (cholesteryl ester transfer protein) promoter -1337 C>T polymorphism protects against coronary atherosclerosis in Japanese patients with heterozygous familial hypercholesterolaemia

CETP (cholesteryl ester transfer protein) and HL (hepatic lipase) play a role in the metabolism of plasma lipoproteins, but the effects of CETP and LIPC (gene encoding HL) genotypes on coronary atherosclerosis may be dependent on LDL (low-density lipoprotein)-receptor activity. Recently, the -1337 C>T polymorphism in the CETP gene has been reported in REGRESS (Regression Growth Evaluation Statin Study) to be a major determinant of promoter activity and plasma CETP concentration. In the present study, we have investigated the effects of the CETP promoter -1337 C>T and LIPC promoter -514 C>T polymorphisms on serum lipid profiles and risk of coronary atherosclerosis in 206 patients (154 males) with heterozygous FH (familial hypercholesterolaemia). To evaluate coronary atherosclerosis, we used CSI (coronary stenosis index) calculated from coronary angiograms. The CETP -1337 T allele was less frequent in subjects with a CSI > or =14 (mean value) in the group with coronary artery disease (P=0.04, as determined by chi(2) test). ANOVA revealed that HDL-C (high-density lipoprotein-cholesterol) and triacylglycerol (triglyceride) levels were not significantly higher in the presence of the CETP promoter -1337 T allele. Combined with LIPC promoter polymorphisms, HDL-C levels were highest and CSI were lowest with CETP -1337 CT+TT and LIPC -514 CC genotypes, but a significant interaction was not shown. A multiple logistic regression analysis revealed that, in patients with coronary atherosclerosis, the CETP- 1337 CC genotype was a significant genetic risk factor in FH (odds ratio=2.022; P=0.0256). These results indicate that the CETP promoter -1337C>T polymorphism is associated with the progression of coronary atherosclerosis in Japanese patients with FH, independent of HDL-C and triacylglycerol levels.     

Apolipoprotein E polymorphisms in Mexican patients with coronary artery disease.

BACKGROUND: Apolipoprotein E polymorphisms have important effects on plasma lipid levels and in the genetic susceptibility to development of cardiovascular diseases. Thus, the purpose of this study was to investigate the association of apolipoprotein E polymorphisms with coronary artery disease and with plasma lipid levels in a group of Mexican Mestizo patients. METHODS: Apolipoprotein E polymorphisms were determined in 156 Mexican patients with coronary artery disease and 200 non-related healthy controls using the restriction fragment length polymorphism technique. The correlation of these polymorphisms with lipid profile (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides) in the patient group was determined. RESULTS: A similar distribution of allele and genotype frequencies in coronary artery disease patients and healthy controls was found. Higher serum levels of high-density lipoprotein cholesterol and lower levels of low-density lipoprotein cholesterol, triglycerides and glucose were found in patients with the APOE*2/3 genotype when compared to patients with the APOE*3/4 and APOE*3/3 genotypes, although these differences were not significant. CONCLUSIONS: Our data suggest that genetic variation at the APOE is not a genetic factor related to the genetic susceptibility to coronary artery disease in Mexican individuals, but the role of this polymorphism in determining the lipid profile cannot be excluded.     

Associations of apolipoprotein E exon 4 and lipoprotein lipase S447X polymorphisms with acute ischemic stroke and myocardial infarction.

BACKGROUND: Because apolipoprotein E (apoE) and lipopoprotein lipase (LPL) polymorphisms interact with each other and with other factors to affect lipid metabolism, we sought to determine their separate and combined effects in association with ischemic vascular disease. METHODS: We performed a case-control study of 816 subjects: 246 acute ischemic stroke patients, 234 acute myocardial infarction patients, and 336 controls. APOE exon 4 and LPL S447X genotypes were determined. RESULTS:APOE epsilon2 and epsilon4 homozygotes were increased in stroke (4.5% vs. 1.0%, p = 0.008), while in myocardial infarction the epsilon4 allele was increased (12.6% vs. 9.5%, p = 0.006) but epsilon2 was decreased (3.7% vs. 12.1%, p = 0.000006). For subjects with either APOE epsilon2 or epsilon4 alleles, LPL X alleles were increased in vascular disease (OR = 2.2, p = 0.01). LPL X alleles displayed opposite tendencies toward association with disease when subjects were divided by sex, smoking, or APOE genotype. Meta-analysis and regression analysis of previous studies supported the sex and smoking dichotomies. CONCLUSION: This is the first report of an association of vascular disease with an interaction of APOE exon 4 and LPL S447X genotypes. Therefore, APOE genotypes and LPL S447X interactions with apoE, sex, and smoking may affect the risk of myocardial infarction and ischemic stroke.     

Polymorphisms in the apolipoprotein E gene regulatory region in relation to coronary heart disease and their effect on plasma apolipoprotein E.

In a previous study which examined the distribution of apolipoprotein E genotypes and plasma levels in a sample of male coronary heart disease (CHD) patients and controls, we found a significant excess of the genotypes carrying APOE*4 allele in CHD men (18.2%) vs. controls (9.6%) and an association between the APOE*4 allele and the lowest concentrations of apoE. In the present investigation, we re-examined in the same samples two recently identified polymorphisms in the promoter region of APOE, -491A/T and -427T/C, which may alter the level of apoE expression. No differences in the distributions of the -491A/T genotypes and alleles were observed between cases and controls (-491*A = 0.760 and 0.757 respectively). Polymorphism -427T/C showed in CHD patients an excess of -427*C allele (patients vs. controls = 0.123 vs. 0.074) and corresponding genotypes that was marginally significant. Stratification of the samples according to the presence/absence of APOE*4 showed that the excess of the -427*C allele concerned only CHD patients not carrying APOE*4 allele (patients vs. controls = 0.133 vs. 0.061; p=0.017). This result suggests that the presence of -427*C allele could represent a risk for developing CHD in subjects with E2/E2, E3/E2, and E3/E3 genotypes. Studies carried out on patients with Alzheimer's disease demonstrated that -491A/T and -427T/C polymorphisms affect the level of plasma apoE. In the present study, carried out on CHD patients and controls, the genetic variation at -427 and -491 sites of the APOE regulatory region had no apparent effect on apoE plasma concentration.     

Common variants of Cholesteryl ester transfer protein gene and their association with lipid parameters in healthy volunteers of Tamilian population

BACKGROUND: Cholesteryl ester transfer protein (CETP) is involved in a key pathway of reverse cholesterol transport implicated in atherosclerosis and coronary heart disease. CETP gene is known to have many single nucleotide polymorphisms which have been associated with CETP activity and plasma high density lipoprotein cholesterol (HDL-C) concentrations. No data on the prevalence of these polymorphisms and their phenotypic association is available in South Indian population. METHODS: Three CETP polymorphisms: TaqIB, -629C/A and I405V were studied in 171 healthy volunteers from Tamilnadu, a major population of South India. Subjects were clinically examined and lipid profile was estimated. Genotyping was performed by PCR-RFLP and genotype frequencies estimated. RESULTS: The allele frequencies of TaqIB: B1 allele was 0.51; -629C/A: C allele was 0.36; and that of I405V: I allele was 0.47. Study of association between these three polymorphisms and plasma lipid concentrations revealed no significant differences in lipid parameters between genotypes. A gender based subgroup analysis revealed a significant increase in HDL-C in men with B2B2 genotype and decrease in TG in B1B2 genotype. Analysis of the combined effect of multiple mutant genotypes revealed that as the number of mutant genotypes increased, the concentrations of low density lipoprotein-cholesterol (LDL-C), HDL-C and total cholesterol (TC) increased whereas that of triglyceride (TG) decreased in the group of three mutant genotypes significantly. CONCLUSION: The frequency of B2 and A alleles of TaqIB and -629C/A polymorphisms were highest in Tamilian population when compared to other major ethnic groups while that of V allele of I405V polymorphism is between Caucasians and African Americans. Taq1B polymorphism was associated with HDL-C and TG concentrations only in men. Combination of these three polymorphisms was significantly associated with lipid profile than the individual polymorphisms.     

Pioglitazone Decreases Plasma Cholesteryl Ester Transfer Protein Mass, Associated With a Decrease in Hepatic Triglyceride Content, in Patients With Type 2 Diabetes

OBJECTIVE

Thiazolidinediones reduce hepatic steatosis and increase HDL cholesterol levels. In mice with human-like lipoprotein metabolism (APOE*3-Leiden.CETP transgenic mice), a decrease in hepatic triglyceride content is associated with a decrease in plasma cholesteryl ester transfer protein (CETP) mass and an increase in HDL levels. Therefore, the aim of the present study was to assess the effects of pioglitazone on CETP mass in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We included 78 men with type 2 diabetes (aged 56.5 ± 0.6 years; HbA1c 7.1 ± 0.1%) who were randomly assigned to treatment with pioglitazone (30 mg/day) or metformin (2000 mg/day) and matching placebo, in addition to glimepiride. At baseline and after 24 weeks of treatment plasma HDL cholesterol levels and CETP mass were measured, and hepatic triglyceride content was assessed by proton magnetic resonance spectroscopy.

RESULTS

Pioglitazone decreased hepatic triglyceride content (5.9 [interquartile range 2.6–17.4] versus 4.1 [1.9–12.3]%, P < 0.05), decreased plasma CETP mass (2.33 ± 0.10 vs. 2.06 ± 0.10 μg/ml, P < 0.05), and increased plasma HDL cholesterol level (1.22 ± 0.05 vs. 1.34 ± 0.05 mmol/l, P < 0.05). Metformin did not significantly change any of these parameters.

CONCLUSIONS

A decrease in hepatic triglyceride content by pioglitazone is accompanied by a decrease in plasma CETP mass and associated with an increase in HDL cholesterol levels. These results in patients with type 2 diabetes fully confirm recent findings in mice.Hepatic steatosis is a prevalent condition in patients with type 2 diabetes and is associated with an increased cardiovascular risk (1,2). Furthermore, many patients with type 2 diabetes display dyslipidemia characterized by high plasma levels of apolipoprotein (apo) B-lipoproteins and triglycerides and low plasma levels of HDL cholesterol. Recently, Toledo et al. (3) showed that hepatic steatosis is associated with more severe hyperlipidemia in type 2 diabetes, which might contribute to the increased risk of cardiovascular disease.To reduce this increased cardiovascular risk in type 2 diabetes, regular treatment algorithms include lipid-lowering drugs. Our previous studies in APOE*3-Leiden.CETP transgenic mice, a well-established model for human-like lipoprotein metabolism, showed that treatment with either statins (4), fibrates (5), or niacin (6) resulted in a reduction in plasma apoB-lipoproteins and triglyceride levels and an increase in HDL cholesterol. Moreover, these treatments reduced hepatic lipid content (i.e., both triglycerides and cholesterol) as well as the hepatic expression and plasma levels of cholesteryl ester transfer protein (CETP) (4–6). CETP is a protein that mediates the heteroexchange of cholesteryl esters from HDL to (V)LDL with a simultaneous exchange of triglycerides from (V)LDL to HDL. These studies thus suggest that lowering of hepatic lipid content in APOE*3-Leiden.CETP mice increased HDL cholesterol levels by reduction of plasma CETP mass.Because the correlation between hepatic triglyceride content and plasma CETP mass has not been studied in humans, the aim of this study was to evaluate whether the relationship between lowering of hepatic triglyceride content and decreased plasma CETP mass also exists in humans. Hepatic triglyceride content can be lowered by thiazolidinediones, including pioglitazone (7). Indeed, in a previous study, we reported that both antidiabetic drugs pioglitazone and metformin improved insulin sensitivity in men with type 2 diabetes whereas only pioglitazone reduced hepatic triglyceride content (8). Therefore, we used pioglitazone treatment as a model to study the effects of a change in hepatic triglyceride content on CETP mass in patients with type 2 diabetes and used metformin treatment as a negative control.     

The role of common variants of ABCB1, CYP3A4, and CYP3A5 genes in lipid-lowering efficacy and safety of simvastatin treatment

OBJECTIVE: Our objective was to investigate the interactions between common polymorphisms in ABCB1, CYP3A4, and CYP3A5 genes and the lipid-lowering efficacy and safety of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor simvastatin. METHODS: One hundred sixteen hypercholesterolemic patients were prospectively screened by physical examination, medical history, and clinical laboratory evaluation and were included in this study. Subjects entering the study were treated with 20 mg/d simvastatin. Plasma lipid and lipoprotein levels were measured before treatment, after 2 months of treatment, and after 6 months of treatment. Ninety-nine patients completed the 6-month follow-up and were included in the association analysis for treatment efficacy. Seventeen subjects who had adverse drug reactions (ADRs) to simvastatin (ADR group) could not complete the 6-month follow-up and were included in the association analyses for safety. Myalgia was observed in 15 of 17 subjects and was the only ADR included in the association analyses, but other common ADRs were also observed. Myalgia was defined as proximal or diffuse muscle pain, tenderness, or weakness, or both pain and weakness, with normal or slightly increased serum creatine phosphokinase levels. ABCB1 (1236C>T, 2677G>A/T, and 3435C>T), CYP3A4 (-392A>G), and CYP3A5 (6986A>G) allele variants were determined by polymerase chain reaction and restriction mapping. RESULTS: After adjustment for covariates, carriers of the ABCB1 1236T variant allele had a greater reduction in total cholesterol and low-density lipoprotein cholesterol with simvastatin treatment, as compared with homozygotes with the wild-type allele (-29.0% [95% confidence interval (CI), -25.9 to -32.5] versus -24.2% [95% CI, -19.0 to -29.3] [P = .042] and -39.6% [95% CI, -35.8 to -44.0] versus -33.8% [95% CI, -27.4 to -40.2] [P = .042], respectively). Similar results were observed for the 2677G>A/T polymorphism and haplotype data. The 1236T, 2677non-G, and 3435T alleles were less frequent in ADR cases than in the non-ADR group (P < .05 for all single-nucleotide polymorphisms). Haplotype analyses also demonstrated a reduction of the T-non-G-T haplotype frequency (20%) in patients in whom myalgia developed during simvastatin treatment, as compared with the non-ADR group (41.4%) (P = .03). No significant associations were observed between the CYP3A4 -392A>G and CYP3A5*3 allele variants and the efficacy or tolerability of simvastatin. CONCLUSIONS: Our data suggest an association of ABCB1 gene polymorphisms and the efficacy and safety of simvastatin.     

Association between the cholesteryl ester transfer protein TaqI-detectable B polymorphism and low high-density lipoprotein cholesterol concentration in Saudis

Plasma concentrations of HDL (high-density lipoprotein) cholesterol are low in the Saudi Arabian population. A B polymorphism at the CETP (cholesteryl ester protein transfer) locus that is detectable with the restriction enzyme Taq I is a genetic determinant of the plasma HDL cholesterol concentration. We assessed the relationship between the Taq I B CETP polymorphism and lipid and apolipoprotein concentrations in a study sample of 335 Saudi residents. The Taq I B1 and B2 allele frequencies were 0.54 and 0.46 respectively, similar to those in other populations. HDL cholesterol levels in B2B2 homozygotes were significantly higher than in B1B1 homozygotes [1.01 (0.3) compared with 0.92 (0.2) mmol/l; mean (S.D.); P=0.03]. There was also a significant difference between the B2B2 and B1B1 homozygotes with regard to apolipoprotein AI concentration [123.6 (16.4) compared with 113.7 (13.9) mg/dl; P=0.04]. This genetic variation was independent of metabolic risk factors known to influence HDL cholesterol levels. The allele frequency of the Taq I B CETP polymorphism and its relatively modest impact on HDL cholesterol concentrations argue against an important role for this allele, or for strongly linked loci, in determining the low levels of HDL cholesterol seen in the Saudi population.     

Alcohol intake modulates the effect of a polymorphism of the cholesteryl ester transfer protein gene on plasma high density lipoprotein and the risk of myocardial infarction.

A polymorphism of the CETP gene (CETP/TaqIB) with two alleles B1 (60%) and B2 (40%) has been investigated in relation to lipid variables and the risk of myocardial infarction in a large case-control study (ECTIM) of men aged 25-64. No association was observed between the polymorphism and LDL or VLDL related lipid variables. Conversely, B2 carriers had reduced levels of plasma CETP (P < 0.0001) and increased levels of HDL cholesterol (P < 0.0001) and of other HDL related lipid variables. The effects of the polymorphism on plasma CETP and HDL cholesterol were independent, suggesting the presence of at least two functional variants linked to B2. A search for these variants on the coding sequence of the CETP gene failed to identify them. The effect of B2 on plasma HDL cholesterol was absent in subjects drinking < 25 grams/d of alcohol but increased commensurably, with higher values of alcohol consumption (interaction: P < 0.0001). A similar interaction was not observed for plasma CETP. The odds-ratio for myocardial infarction of B2 homozygotes decreased from 1.0 in nondrinkers to 0.34 in those drinking 75 grams/d or more. These results provide the first demonstration of a gene-environment interaction affecting HDL cholesterol levels and coronary heart disease risk.     

The genes of atherosclerosis and cardiovascular diseases

The aim of the work was to study polymorphism of atherosclerosis-related genes in patients with different forms of coronary heart disease (CHD) and chronic cerebral ischemia (CCI) in comparison with long-living subjects. Analysis included the distribution of genotypes and alleles of functional polymorphisms of lipid metabolism genes, viz. HindIII--polymorphism of lipoproteinase (LPL) gene; HhaI--polymorphism of apoE gene; TaqIB--polymorphism of cholesterol ether transfer protein (CETP) gene; I/D--polymorphism of angiotensin converting enzyme (ACE) in CHD and CCI patients of different age groups including long livers and those presenting with different clinical variants of CHD and CCI (FC II-III stable angina of effort, acute myocardial infarction, post-infarction cardiosclerosis, acute coronary syndrome) and control subjects. The study revealed potential molecular-genetic markers for primary and secondary prophylaxis of CHD and CCI. It was shown that DD genotypes of ACE gene, H+/+ of LPL gene and E3E4 are associated with an enhanced probability of myocardial infarction (IM) in CHD patients and can be regarded as high risk markers. The DD genotype is associated with an increased risk of recurrent MI, life-threatening post-IM complications and severe cardiac insufficiency as well as peculiar personality and behavioural traits (animosity and type A behaviour)--psychological risk factors of CHD and predictors of delayed application for medical aid. E2 allele of the ApoE gene and H allele of the LPL gene occur much more frequently in CHD patients aged above 90 years (long livers) than in younger subjects; hence, their value as markers of stable ischemic disease. Protective effect in terms of favourable clinical course of CCI and life expectancy is especially pronounced in subjects with a combination of genotypes with E2E3 + H+H-, E2E2 + H+H-, E3E3 + H-H-genes of ApoE and LPL. B2B2 genotype of CETP gene increases the risk of stable CCI and B1B1 genotype of CETP gene enhances predisposition to cardiovascular pathology.     

汉族人胆固醇酯转运蛋白TaqⅠ B基因多态性与2型糖尿病的关系

目的分析胆固醇酯转运蛋白(CETP)血浆水平及其TaqⅠB基因多态性与2型糖尿病(T2DM)的关系。方法采用聚合酶链反应限制性片段长度多态性(PCR-RFLP)技术检测103例健康对照组、102例T2DM患者CETP第一内含子TaqⅠB多态性基因型,ELISA方法检测血浆CETP浓度,探讨了其对血脂、脂蛋白和apo水平的影响。结果T2DM组血浆CETP水平明显高于对照组;两组CETPTaqⅠB多态性基因型和等位基因频率分布差异无显著性意义,与性别、家族史、吸烟史及体质指数(BMI)无明显相关性。对照组CETPTaqⅠB等位基因型与血脂水平之间无明显关联性,但T2DM组不同基因型间HDL-C与apoAⅠ水平差异有统计学意义,B1等位基因频率与低HDL-C血症密切相关。结论CETP水平、CETPTaqⅠB基因多态性与T2DM脂代谢存在一定的相关性,可能是糖尿病脂代谢异常的重要遗传因素。     

The -250G>A polymorphism in the hepatic lipase gene promoter influences plasma lipid profile and lipoprotein ratio in patients with ischemic stroke

Objective: To evaluate the influence of –250G>A (rs2070895) polymorphism in hepatic lipase gene (LIPC) promoter on plasma lipid parameters of ischemic stroke patients.Methods: A total of 100 stroke patients and 100 control subjects matched for sex (59 men and 41 women) and age were selected. Hepatic lipase activity and lipid profiles were measured while lipoprotein ratios were calculated. Genotyping of the –250G>A promoter polymorphism of the LIPC was performed by the polymerase chain reaction and restriction fragment length polymorphism method combined with 2％ gel electrophoresis and then confirmed by direct sequencing. The LIPC promoter gene sequencing data were compared with refseqNG011465.1 LIPC from GenBank. Results: The frequencies of GG, GA and AA genotypes of LIPC rs2070895 polymorphism were 39％, 45％ and 16％ for the control, 10％, 37％ and 53％ for the stroke subjects (P<0.0001), respectively. The frequencies of G and A alleles were 61.5％ and 38.5％ for the control, and 28.5％ and 71.5％ for the stroke subjects (P<0.0001). Our study shows that the mutant allele of the LIPC promoter was associated with dyslipidemia, lower hepatic lipase activity, and this variation contributed to the increased defective plasma high-density lipoprotein-cholesterol (HDL-C), HDL2-C and HDL3-C concentration for both subjects. The control subjects had 6 single nucleotide polymorphism and 6 amino acid substitutions while the stroke subjects had 32 single nucleotide polymorphism and 20 amino acid substitutions. Conclusions: LIPC –250G>A polymorphism can influence plasma lipid profiles and lipoprotein ratios in patients with ischemic stroke.     

Prolonged caloric restriction in obese patients with type 2 diabetes mellitus decreases plasma CETP and increases apolipoprotein AI levels without improving the cholesterol efflux properties of HDL

OBJECTIVE

Using a mouse model for human-like lipoprotein metabolism, we observed previously that reduction of the hepatic triglyceride (TG) content resulted in a decrease in plasma cholesteryl ester transfer protein (CETP) and an increase in HDL levels. The aim of the current study was to investigate the effects of prolonged caloric restriction in obese patients with type 2 diabetes mellitus, resulting in a major reduction in hepatic TG content, on plasma CETP and HDL levels.

RESEARCH DESIGN AND METHODS

We studied 27 obese (BMI: 37.2 ± 0.9 kg/m²) insulin-dependent patients with type 2 diabetes mellitus (14 men and 13 women, aged 55 ± 2 years) who received a 16-week very low calorie diet (VLCD). At baseline and after a 16-week VLCD, plasma lipids, lipoproteins, and CETP were measured. Furthermore, functionality of HDL with respect to inducing cholesterol efflux from human monocyte cells (THP-1) was determined.

RESULTS

A 16-week VLCD markedly decreased plasma CETP concentration (−18%; P < 0.01) and increased plasma apolipoprotein (apo)AI levels (+16%; P < 0.05), without significantly affecting plasma HDL-cholesterol and HDL-phospholipids. Although a VLCD results in HDL that is less lipidated, the functionality of HDL with respect to inducing cholesterol efflux in vitro was unchanged.

CONCLUSIONS

The marked decrease in hepatic TG content induced by a 16-week VLCD is accompanied by a decrease in plasma CETP concentration and an increase in apoAI levels, without improving the cholesterol efflux properties of HDL in vitro.Patients with type 2 diabetes mellitus display a typical atherogenic dyslipidemia marked by increased plasma triglycerides (TG) and VLDL-cholesterol concentrations and decreased HDL-cholesterol levels. Furthermore, hepatic steatosis, which is also strongly associated with cardiovascular disease risk (1,2), is frequently observed in patients with type 2 diabetes mellitus (3–5).We demonstrated previously that the HDL-raising effect of various classical lipid-lowering drugs was caused by a reduction in plasma cholesteryl ester transfer protein (CETP) that mediates the net transfer of cholesteryl esters from HDL to (V)LDL. In APOE*3-Leiden.CETP mice, a well-established animal model for human-like lipoprotein metabolism, statins (6), fibrates (7), and niacin (8) decrease the hepatic lipid content (i.e., both TG and cholesterol), resulting in a decreased hepatic CETP expression accompanied by decreased plasma CETP levels and a consequently increased plasma HDL. Recently, we showed that a similar mechanism may account for the HDL-raising effect of pioglitazone in humans. In patients with type 2 diabetes mellitus, pioglitazone decreased hepatic TG content (9), accompanied by a decrease in plasma CETP concentration and increase in HDL level (10). In contrast, metformin did not affect either hepatic TG, plasma CETP, or HDL levels (10).Lifestyle interventions such as diet-induced weight reduction and exercise are very important in the treatment of obese patients with type 2 diabetes mellitus. Recently, we reported that a 16-week very low calorie diet (VLCD) in obese patients with type 2 diabetes mellitus significantly decreased plasma total cholesterol and TG levels and markedly reduced hepatic TG content (11), but the potential beneficial effect of a VLCD on plasma CETP and HDL levels has not been studied. Therefore, using plasma samples from that study (11), we investigated whether prolonged caloric restriction reduces CETP concentration and thereby increases HDL levels in obese patients with type 2 diabetes mellitus.     

The common polymorphism of apolipoprotein E: geographical aspects and new pathophysiological relations.

Apolipoprotein E (apoE) has important functions in systemic and local lipid transport, but also has other functions. The gene (APOE) shows a common polymorphism with three alleles--APOE*2, APOE*3, and APOE*4. Their frequencies vary substantially around the world, but APOE*3 is the most common almost everywhere and is often considered to be the ancestral or "wild-type" allele for that reason. However, there are several arguments for APOE*4 being the ancestral allele. But then, why has APOE*3 become so frequent? And why has APOE*4 not become extinct? The proportion of APOE*4 carriers increases from only 10-15% in southern Europe to 40-50% in the north. The gradient may be a trace of the demic expansion of agriculture that began about 10,000 years ago, but it may also reflect the possibility that APOE*4 carriers are less likely to develop vitamin D deficiency. The common APOE polymorphism is associated with varying risk of cardiovascular disease and Alzheimer's disease, but other interesting aspects may emerge in the future.     

Association between apolipoprotein E4 and rehabilitation outcome in hospitalized ischemic stroke patients

OBJECTIVE: To determine the value of apolipoprotein E4 (APOE*E4) allele in predicting discharge impairment and disability in ischemic stroke patients after acute rehabilitation. DESIGN: Prospective study comparing results of rehabilitation in patients with different APOE genotypes. SETTING: Acute neurologic rehabilitation department in Israel. PARTICIPANTS: One hundred one consecutive patients 75 years old or less with a first ischemic stroke. INTERVENTIONS: Not applicable.Main Outcome Measure: Impairment, as measured by the National Institutes of Health Stroke Scale (NIHSS), and disability, as assessed with the FIM trade mark instrument. RESULTS: On admission, there was no significant difference in the FIM or NIHSS measurements between the apo E4 group and other patients, but the prevalence of aphasia was 2.07 times more frequent in those with the APOE*E4 genotype (95% confidence interval, 0.98-4.4). A logistic regression model demonstrated that score measurements on admission were highly predictive of the NIHSS score at discharge (receiver operator curve=96.1%), whereas the presence of the APOE*E4 genotype did not add significantly to the model in predicting poorer rehabilitation treatment outcome as measured by the FIM or the NIHSS. CONCLUSIONS: The presence of the apo E4 allele did not predict a poorer outcome of rehabilitation treatment after ischemic stroke, but it was associated with an increased prevalence of aphasia. Further studies are warranted to confirm this association.     

Integrated single-label liquid-phase assay of APOE codons 112 and 158 and a lipoprotein study in British women

BACKGROUND: Apolipoprotein E (APOE) is an important element of lipid metabolism and, hence, cardiovascular disorders. APOE has 3 main allelic variants: epsilon3, epsilon4, and epsilon2. Of these, epsilon3 is the most common, followed by epsilon4 and epsilon2. The associations of these isoforms with cardiovascular disorders and Alzheimer disease have been widely studied in different populations. Most of the genotyping in these studies has been performed with gel-based methods, which have important limitations, particularly for large epidemiologic studies. We therefore developed an integrated "one-tube" liquid-phase assay. METHODS: To measure APOE isoforms, we developed an integrated single-label liquid-phase fluorescence assay containing 2 PCR primers, 2 probes, and 2 quencher oligonucleotides. We used a 384-well LightTyper, but the assay would be generically applicable for use with any fluorescence detector with thermal ramp control. We validated this method and applied it in the British Women's Heart and Health Study. RESULTS: There were 4 melting peaks, at 41, 56, 61, and 69 degrees C, which generated 6 distinctive patterns representing genotypic combinations of epsilon3, epsilon4, and epsilon2. The magnitude and direction of the associations found with total cholesterol, HDL-cholesterol, triglycerides, and estimated LDL-cholesterol were consistent with previous reports. CONCLUSION: The one-tube LightTyper assay presented here enables accurate, convenient, and economical genotyping of APOE and can be used for large epidemiologic studies.     

Genetic analysis of Indian subjects with clinical features of possible type IIa hypercholesterolemia

We performed genetic analysis in 55 patients with clinical features of possible type IIa hypercholesterolemia and 76 normolipemic healthy subjects for mutations and polymorphisms in the low-density lipoprotein (LDL) receptor (LDLR), apolipoprotein B-100 (APOB), apolipoprotein E (APOE), and hepatic lipase (LIPC) genes to elucidate the important genetic factors that can influence cholesterol levels in our population. None of the subjects showed mutations in part of exon 26 of the APOB gene, whereas two class 5 mutations were identified in exon 9 of the LDLR gene. First, an E387K mutation was observed in a Gujarati family in which both the parents were heterozygous for the mutation. Second, a L393R mutation was observed in a 38-year-old female. We found no correlation between LIPC -514C/T genotypes and cholesterol levels whereas the apoepsilon4 allele frequency was significantly higher in cases and the apoE4 genotype was found to influence total cholesterol levels.     

Synergistic effect between apolipoprotein E and angiotensinogen gene polymorphisms in the risk for early myocardial infarction

BACKGROUND: Several studies based on different populations worldwide have described an association between cardiovascular diseases and genetic variations in the apolipoprotein E (A:POE), angiotensinogen (A:GT), angiotensin receptor type 1 (A:T1R), and angiotensin-converting enzyme (A:CE) genes. In addition, there is growing evidence of an interaction between hypercholesterolemia and the renin-angiotensin system in the risk for hypertension and atherosclerosis. METHODS: To determine whether the DNA polymorphisms in A:POE (epsilon2, epsilon3, and epsilon4 alleles), A:GT (M235T), A:T1R (1166 A:/C:), and ACE (I:/D:) are associated with early onset of myocardial infarction (MI), we genotyped 220 patients and 200 controls <55 years of age. Patients and controls were males from the same homogeneous Caucasian population. Data concerning hypertension, diabetes, and tobacco consumption were recorded. The lipid profiles of patients and controls were also determined. RESULTS: APOE, ACE, AGT, and AT1R allele and genotype frequencies did not differ between patients and controls. None of these polymorphisms was related to the biochemical values in patients or controls. The frequency of individuals who were both APOE epsilon4 allele carriers and AGT-TT homozygotes was significantly higher in patients than in controls (11% vs 3.5%; P: = 0.0037). In patients, the frequency of epsilon4 carriers was significantly higher (P: <0.00001) in those who were AGT-TT (46%) than those who were AGT-MT/MM (14%). Mean cholesterol was significantly higher in AGT-TT + APOE epsilon34/44 patients than in the TM/MM + epsilon34/44 or TT + epsilon23/33 genotypes (P: = 0. 029). CONCLUSIONS: Our data suggest a synergistic effect between the APOE and AGT polymorphisms and early MI. The increased risk could be mediated in part through higher cholesterol concentrations among individuals who are AGT-TT + APOE epsilon4 allele carriers.     

Association of apolipoproteins C3 and E with metabolic changes in HIV-infected adults treated with a protease-inhibitor-containing antiretroviral therapy

OBJECTIVE: To examine the relationship between plasma levels of apolipoproteins C3 (APOC3) and E (APOE) and the presence of lipid and carbohydrate metabolism abnormalities or clinical signs of lipodystrophy in HIV-1-infected patients started with a protease-inhibitor-containing antiretroviral therapy. METHODS: The Aproco (Antiproteases Cohort) Study enrolled 1,181 HIV-1-infected adults in 47 French healthcare centres from May 1997 to June 1998. From December 1998 through July 1999, the APROCO-Metabolic Complications (APROCO-MC) cross-sectional study was performed at the month 20 visit for those patients enrolled in 1997 and at the month 12 visit for those enrolled in 1998. The current analysis presents results from a subset of patients who had undergone additional tests to measure APOC3 and APOE in order to study their relationship with metabolic syndrome (n=157) and abnormal results in an oral glucose tolerance test (n=135). RESULTS: Increases in triglycerides and non-high-density lipoprotein (HDL) cholesterol were associated with significantly higher levels of APOC3, in both Lp B (lipoproteins containing apolipoprotein B) and Lp non-B (lipoproteins free of apolipoprotein B), and a significant higher level of APOE Lp B. APOC3 and APOC3 Lp non-B were increased when glucose metabolism abnormalities were more severe. The presence of a metabolic syndrome was associated with increased plasma APOC3, APOC3 Lp B and APOC3 Lp non-B levels. In a multiple regression analysis, high levels of APOC3 in Lp B and APOC3 Lp non-B were associated with the presence of clinical signs of lipodystrophy, even after adjustment for triglycerides and HDL-cholesterol levels. CONCLUSIONS: Lipid and/or glucose metabolism abnormalities in treated HIV-1-infected patients are associated with increased levels of APOC3 and, to a lesser extent, APOE plasma concentrations. Increased values are also related to clinical signs of insulin resistance and lipodystrophy.