Molecular variation at the apolipoprotein B gene locus in relation to lipids and cardiovascular disease: a systematic meta-analysis.

Apolipoprotein B (apoB) is the sole protein component of low-density lipoprotein (LDL) and is thought to play an important role in atherogenesis. We performed a meta-analysis of the associations between the three most frequently investigated polymorphisms (XbaI, signal peptide insertion/deletion, EcoRI) in the apolipoprotein B (APOB) gene, lipid parameters, and the risk of ischemic heart disease (IHD). We restricted our analysis to Caucasians.

Regression of carotid and femoral artery intima-media thickness in familial hypercholesterolemia: treatment with simvastatin.

Objective: To investigate whether high-dose simvastatin therapy could reduce carotid and femoral artery intima-media thickness (IMT) in patients with familial hypercholesterolemia (FH) to prevent cardiovascular disease.

Background: Imaging of arterial walls with B-mode ultrasonography is increasingly used as a noninvasive surrogate marker of cardiovascular disease. Intervention trials using this modality have shown that by reducing risk factors, progression of atherosclerosis was inhibited.

Restoration of endothelial function by increasing high-density lipoprotein in subjects with isolated low high-density lipoprotein.

Background: Loss-of-function mutations in the ATP-binding cassette (ABCA)-1 gene locus are the underlying cause for familial hypoalphalipoproteinemia, providing a human isolated low-HDL model. In these familial hypoalphalipoproteinemia subjects, we evaluated the impact of isolated low HDL on endothelial function and the vascular effects of an acute increase in HDL.

Methods And Results: In 9 ABCA1 heterozygotes and 9 control subjects, vascular function was assessed by venous occlusion plethysmography.

Efflux and atherosclerosis: the clinical and biochemical impact of variations in the ABCA1 gene.

Approximately 50 mutations and many single nucleotide polymorphisms have been described in the ABCA1 gene, with mutations leading to Tangier disease and familial hypoalphalipoproteinemia. Homozygotes and heterozygotes for mutations in ABCA1 display a wide range of phenotypes. Identification of ABCA1 as the molecular defect in these diseases has allowed for ascertainment based on genetic status and determination of genotype-phenotype correlations and has permitted us to identify mutations conferring a range of severity of cellular, biochemical, and clinical phenotypes.

Variants of toll-like receptor 4 modify the efficacy of statin therapy and the risk of cardiovascular events.

Background: Atherosclerosis is increasingly considered to be a chronic inflammatory process. We examined whether genetic variants of the toll-like receptor 4 (TLR4), which are correlated with impaired innate immunity and with progression of carotid atherosclerosis, are also associated with coronary atherosclerosis and predict the risk of cardiovascular events.

Methods And Results: Two polymorphisms of the TLR4 gene (Asp299Gly and Thr399Ile) were determined in 655 men with angiographically documented coronary atherosclerosis.

A novel functional polymorphism in the PECAM-1 gene (53G>A) is associated with progression of atherosclerosis in the LOCAT and REGRESS studies.

A 53G>A polymorphism identified in the 5' untranslated region (5'UTR) of the platelet endothelial cell adhesion molecule-1 (PECAM-1) gene alters a putative shear stress responsive element (SSRE). PECAM-1 was shown to be responsive to shear stress and transient transfection of human umbilical vein endothelial cell (HUVECs) with two luciferase reporter constructs driven by the PECAM-1 promoter and 5'UTR showed a response of the 53G allele, not the 53A allele, to shear stress. Association between the 53G>A, and the previously published L125V polymorphism, and coronary atherosclerosis was examined in two angiographic studies.

Surrogate markers of atherosclerosis: impact of statins.

Carotid artery intima-media thickness (IMT) measured by ultrasound has been shown to be correlated with existing cardiovascular disease (CVD) and predictive of CVD in individuals without clinically evident disease. Carotid IMT is now widely used as a surrogate marker for atherosclerotic disease. A number of studies have shown that lipid-lowering therapy with a statin can reduce or reverse carotid IMT progression.

The role of the ABCA1 transporter and cholesterol efflux in familial hypoalphalipoproteinemia.

Defects in the gene encoding for the ATP binding cassette (ABC) transporter A1 (ABCA1) were shown to be one of the genetic causes for familial hypoalphalipoproteinemia (FHA). We investigated the role of ABCA1-mediated cholesterol efflux in Dutch subjects suffering from FHA. Eighty-eight subjects (mean HDL cholesterol levels 0.

Adherence to and dosing of beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitors in the general population differs according to apolipoprotein E-genotypes.

Discontinuation and poor adherence to therapy are major problems during long-term treatment, particularly with cholesterol lowering drugs. Several studies have indicated that the cholesterol lowering effect of statins differs according to apolipoprotein (apo)E genotypes. Low-density lipoprotein-cholesterol lowering capacity appears to be smaller in subjects with the epsilon(4) allele.

Family history and cardiovascular risk in familial hypercholesterolemia: data in more than 1000 children.

Background: Elevated LDL cholesterol (LDL-C) levels in childhood predict cardiovascular disease (CVD) later in life. Familial hypercholesterolemia (FH) represents the paradigm of this relation.

Methods And Results: The objectives of this study were to (1) establish the LDL-C level that provides the most accurate diagnosis of FH in children from families with known FH and (2) assess whether lipoprotein variation in these children is associated with premature CVD in relatives.

Lipoprotein lipase deficiency--rare or common?

Cardiovascular disease is the number one killer in the world. Prevention is the most promising treatment. However, predicting an individual's risk for cardiovascular disease is quite complicated, involving the complex interaction of a plethora of environmental and genetic factors.

The apolipoprotein epsilon4 allele confers additional risk in children with familial hypercholesterolemia.

Children with familial hypercholesterolemia (FH) exhibit substantial variance of LDL cholesterol. In previous studies, family members of children with FH were included, which may have influenced results. To avoid such bias, we studied phenotype in 450 unrelated children with FH and in 154 affected sib-pairs.

Raised serum levels of soluble CD40 ligand in patients with familial hypercholesterolemia: downregulatory effect of statin therapy.

Objectives: In the present study, we investigated the effects of statins on serum levels of soluble CD40 ligand (sCD40L) in patients with familial hypercholesterolemia (FH).

Background: Atherosclerotic disease seems to involve inflammatory and immunologic mechanisms, and sCD40L has recently been identified as one of the key players in the atherosclerotic process. HMG-Co A reductase inhibitors, statins, have been recognized as immunomodulators and reduce cardiovascular events and mortality, but the effects of statins on sCD40L has not been clarified.

Long-term compliance with lipid-lowering medication after genetic screening for familial hypercholesterolemia.

Background: Familial hypercholesterolemia is a common lipid disorder that predisposes to premature cardiovascular disease. Lipid-lowering treatment of affected individuals is widely advocated, and maximum benefit can be obtained if medication is started early. A screening program for familial hypercholesterolemia is ongoing in the Netherlands since 1994.

Early statin therapy restores endothelial function in children with familial hypercholesterolemia.

Objectives: This study was designed to determine whether simvastatin improves endothelial function in children with familial hypercholesterolemia (FH).

Background: Endothelial function measured by flow-mediated dilation of the brachial artery (FMD) is used as a surrogate marker of cardiovascular disease (CVD). Adult studies have shown that statins reverse endothelial dysfunction and therefore reduce the risk for future CVD.

Thrombospondin-2 polymorphism is associated with a reduced risk of premature myocardial infarction.

Objective: Recently, polymorphisms in thrombospondin (THBS) genes coding for THBS-1 (N700S), THBS-2 (T>G substitution in 3'-untranslated region), and THBS-4 (A387P) genes were proposed to modulate the risk of premature coronary artery disease (CAD) or myocardial infarction (MI). It was our objective to verify this hypothesis in an independent cohort.

Methods And Results: We performed a case-control study among patients (n=503) referred to our institution for symptomatic CAD that occurred before the age of 50 years and a group of age- and sex-matched population-based controls free of CAD (n=1071).

Low-density lipoprotein receptor gene mutations and cardiovascular risk in a large genetic cascade screening population.

Background: A large cohort of patients with familial hypercholesterolemia (FH), free from selection for cardiovascular disease (CVD), and their unaffected relatives was collected by genetic cascade screening and examined for the influence of different mutations of the LDL receptor gene on lipoprotein levels and the risk of CVD. Multivariate analyses with adjustment for age, sex, and specific family ties were performed.

Methods And Results: Significant variation of LDL levels was observed among 399 patients with FH with different mutations.

Measurement of subclinical atherosclerosis: beyond risk factor assessment.

Purpose Of Review: Assessment of subclinical atherosclerosis using the current available noninvasive imaging modalities holds promise for individual cardiovascular risk management and monitoring efficacy of therapeutic interventions (i.e. surrogate end-points).

The effectiveness of hydroxy-methylglutaryl coenzyme A reductase inhibitors (statins) in the elderly is not influenced by apolipoprotein E genotype.

We aimed to assess whether the effectiveness of statins in the prevention of myocardial infarction, stroke and total mortality is influenced by apolipoprotein E (apoE) genotype in an elderly population. We used data from the Rotterdam Study, a prospective population-based cohort study in the Netherlands which started in 1990 and included 7983 subjects aged 55 years and older. Subjects who were treated with cholesterol lowering drugs at baseline or with a serum total cholesterol > or = 6.

Consumption of tall oil-derived phytosterols in a chocolate matrix significantly decreases plasma total and low-density lipoprotein-cholesterol levels.

In a randomized, double-blind, placebo-controlled trial we evaluated the effect of dietary chocolates enriched with a wood-based phytosterol-phytostanol mixture, containing 18 % (w/w) sitostanol, compared with placebo dietary chocolates in seventy subjects with primary hypercholesterolaemia (total cholesterol levels below 8 mmol/l). For 4 weeks, participants consumed three servings of the phytosterol-enriched chocolate/d that provided 1.8 g unesterified phytosterols/d or a placebo chocolate in conjunction with a low-fat, low-cholesterol diet.

Differential hs-CRP reduction in patients with familial hypercholesterolemia treated with aggressive or conventional statin therapy.

Background: High sensitivity C-reactive protein (hs-CRP) has emerged as the best studied and most promising marker of inflammation in atherosclerotic vascular disease.

Materials And Methods: The ASAP (effects of Atorvastatin vs. Simvastatin on Atherosclerosis Progression) study was a 2-year randomised, double-blind trial with 325 familial hypercholesterolemia patients, treated with torvastatin 80 mg or imvastatin 40 mg.

Truncation mutations in ABCA1 suppress normal upregulation of full-length ABCA1 by 9-cis-retinoic acid and 22-R-hydroxycholesterol.

Mutations in ABCA1 uniformly decrease plasma HDL-cholesterol (HDL-C) and reduce cholesterol efflux, yet different mutations in ABCA1 result in different phenotypic effects in heterozygotes. For example, truncation mutations result in significantly lower HDL-C and apoliprotein A-I (apoA-I) levels in heterozygotes compared with nontruncation mutations, suggesting that truncation mutations may negatively affect the wild-type allele. To specifically test this hypothesis, we examined ABCA1 protein expression in response to 9-cis-retinoic acid (9-cis-RA) and 22-R-hydroxycholesterol (22-R-OH-Chol) in a collection of human fibroblasts representing eight different mutations and observed that truncation mutations blunted the response to oxysterol stimulation and dominantly suppressed induction of the remaining full-length allele to 5-10% of wild-type levels.

Relationship between stearoyl-CoA desaturase activity and plasma triglycerides in human and mouse hypertriglyceridemia.

Stearoyl-CoA desaturase (SCD) is expressed at high levels in several human tissues and is required for the biosynthesis of oleate (18:1) and palmitoleate (16:1). These monounsaturated fatty acids are the major components of phospholipids, triglycerides, wax esters, and cholesterol esters. Mice with a targeted disruption of the SCD1 gene have very low levels of VLDL and impaired triglyceride and cholesterol ester biosynthesis.