Search

Introduction: Familial hypercholesterolemia (FH) is a highly prevalent condition, predisposing individuals to premature cardiovascular disease and with a genetic basis more complex than initially thought. Advances in molecular technologies have provided novel insights into the role of next-generation-sequencing, the assessment and classification of newly found variants, the complex genotype-phenotype correlation, and the position of FH in the context of other dyslipidaemias. Areas covered: Understanding the scope of genetic determinants of FH has expanded substantially. This article reviews the current literature on the complexity that comes with this incremental knowledge and highlights the added value of genetic testing as an addition to phenotypic diagnosis of FH. Moreover, we discuss the broad genetic basis of FH, with a focus on the three main FH genes, but we also pay attention to polygenic hypercholesterolemia as well as minor and modulator genes involved in FH. Expert opinion: Both the availability and the need for genetic analysis of FH are on the rise as costs of sequencing continue to drop and new therapies require a genetic diagnosis for reimbursement. However, greater use of genetic testing requires more education of healthcare professionals, since molecular technologies will allow for rapid and accurate evaluation of large numbers of detected variants. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the efficacy and safety of icosabutate, an oral, once-daily, first-in-class medication, in reducing non-high-density lipoprotein cholesterol (non-HDL-C) in patients with persistent hypertriglyceridemia despite statin therapy. Methods: The study was designed to randomly assign 140 patients with fasting triglyceride levels ≥ 200 but <500 mg/dl on a stable dose of statin therapy to receive either masked icosabutate 600 mg once daily or a control for 12 weeks. The primary end point was a percentage change in non-HDL-C from baseline to 12 weeks. Results: With icosabutate, non-HDL-C levels were reduced (-9.2%) when compared with the control (-0.4%) for a between-group difference of -7.4% (p = 0.02). Compared with the control, icosabutate reduced triglycerides (-27.0%, p < 0.001), verylow- density lipoprotein (VLDL) cholesterol (-31.5%, p < 0.001) and apolipoprotein C-III (-22.5%, p < 0.001). LDL-C levels did not change (0.5%, p = 0.87). HDL-C (10.2%, p < 0.001) was increased. After 113 subjects had been randomized, the study was terminated due to a partial clinical hold imposed by US regulators after observing QT prolongation at supratherapeutic doses of icosabutate in a dog study. In this study, adverse events were balanced between treatment arms, and there were no discontinuations due to adverse events. Conclusions: Icosabutate was efficacious in lowering non-HDL-C and other biomarkers of cardiovascular risk and was generally well tolerated. [ABSTRACT FROM AUTHOR]

Aims Homozygous autosomal dominant hypercholesterolaemia (hoADH), an orphan disease caused by mutations in low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin–kexin type 9 (PCSK9), is characterized by elevated plasma low-density lipoprotein-cholesterol (LDL-C) levels and high risk for premature cardiovascular disease (CVD). The exact prevalence of molecularly defined hoADH is unknown. Therefore, we investigated the prevalence and phenotypical characteristics of this disease in an open society, i.e. the Netherlands. Methods and results The database of the nationwide ADH molecular diagnostic center was queried to identify all molecularly defined hoADH patients. Carriers of non-pathogenic mutations were excluded. Medical records were analysed for data regarding lipid levels and CVD events. Of 104 682 individuals screened for molecular defects, 49 were classified as hoADH (0.05%); 20 were true homozygotes, 25 were compound heterozygotes for LDLR mutations, and 4 were homozygous for APOB mutations. No bi-allelic PCSK9 mutation carriers were identified. Consequently, the prevalence of hoADH was estimated to be ∼1 : 300 000. Mean LDL-C levels prior to lipid-lowering treatment were 12.9 ± 5.1 mmol/L (range 4.4–21.5 mmol/L). Surprisingly, only 50% of the patients met the clinical criteria for hoADH (LDL-C >13.0 mmol/L); 29% of patients suffered from a CVD event. Conclusion The prevalence of molecularly defined hoADH is much higher and the clinical phenotype is more variable than previously assumed. In light of the fact that novel therapies are, or will be registered for the treatment of hoADH patients, an uniform definition of hoADH either as a phenotypic or molecular entity is warranted in order to identify patients who are considered to be eligible for these novel agents. [ABSTRACT FROM PUBLISHER]

Background There is an ongoing debate about the performance of non-high-density lipoprotein cholesterol (non- HDL-C) compared with apolipoprotein B (apo B) in the prediction of coronary heart disease ( CHD) risk. Therefore, we compared the associations between non- HDL-C and apo B in regard to CHD among apparently healthy Western European individuals. Design In the European Prospective Investigation into Cancer and Nutrition ( EPIC)-Norfolk prospective population study, 25 639 men and women aged 45-79 years were followed for 11·4 ± 2·8 years. Those with diabetes or prevalent CHD at baseline were excluded. A total of 2066 (12·1%) participants developed CHD during 195 692 person-years follow-up. Results The multivariable-adjusted hazard ratio [ HR] of future CHD per one standard deviation increase was 1·22 [95% confidence interval ( CI): 1·17-1·27] for LDL-C, 1·26 (95% CI 1·20-1·31) for non- HDL-C and 1·19 (95% CI 1·14-1·24) for apo B, respectively. The multivariable-adjusted HR of future CHD in the highest quartile LDL-C was 1·67 (95% CI: 1·47-1·91). For non- HDL-C and apo B, these respective HRs were 1·87 (95% CI: 1·62-2·15) and 1·56 (95% CI: 1·36-1·78). Kaplan-Meier survival analyses showed that there was incremental and comparable increase in risk of CHD with increasing quartiles of both non- HDL-C and apo B. Conclusions In this prospective study, non- HDL-C and apo B were comparable in their ability to predict risk of future CHD. [ABSTRACT FROM AUTHOR]

Aims Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) has raised several points of debate. We quantified the proportion of individuals meeting the JUPITER criteria, determined their risk profile, and their risk of coronary heart disease (CHD) events during a long-term follow-up in a contemporary European cohort. Methods and results A total of 25 639 participants aged between 45 and 79 years were followed for 11.4 ± 2.8 years in EPIC-Norfolk population cohort. A total of 8397 individuals with complete data available were considered potentially eligible for primary prevention. A total of 846 (10.1%) individuals fulfilled the JUPITER criteria [low-density lipoprotein cholesterol-C (LDL-C) <3.4 mmol/L/C-reactive protein ≥2 mg]. This group had a 10-person-year event rate of 14.6% compared with 7.0% for those with LDL-C <3.4 mmol/L/C-reactive protein <2 mg (P = 0.001); the corresponding adjusted hazard ratio for future CHD was 1.70 (95% CI: 1.31–2.21). The group fulfilling JUPITER criteria had significantly higher CHD risk compared with those with LDL-C ≥3.4 mmol/L and C-reactive protein <2 mg/L. Among individuals who did not qualify for statin therapy based on the Society of Cardiology Systematic COronary Risk Evaluation (SCORE) (n = 4652) or ATP III criteria (n = 4466), 18.1 and 18.9%, respectively, would have qualified using the JUPITER criteria. Conclusion In this European cohort, JUPITER-eligible individuals had significantly higher event rates compared with those with LDL-C <3.4 mmol/L/C-reactive protein <2 mg and LDL-C ≥3.4 mmol/L/C-reactive protein <2 mg/L. Application of the JUPITER criteria qualified almost one-fifth of the population for statin therapy that otherwise would not have qualified based on SCORE or ATP III criteria. [ABSTRACT FROM PUBLISHER]

Aims Recent genome-wide association studies suggest that IDOL (also known as MYLIP) contributes to variation in circulating levels of low-density lipoprotein cholesterol (LDL-C). IDOL, an E3-ubiquitin ligase, is a recently identified post-transcriptional regulator of LDLR abundance. Briefly, IDOL promotes degradation of the LDLR thereby limiting LDL uptake. Yet the exact role of IDOL in human lipoprotein metabolism is unclear. Therefore, this study aimed at identifying and functionally characterizing IDOL variants in the Dutch population and to assess their contribution to circulating levels of LDL-C. Methods and results We sequenced the IDOL coding region in 677 individuals with LDL-C above the 95th percentile adjusted for age and gender (high-LDL-C cohort) in which no mutations in the LDLR, APOB, and PCSK9 could be identified. In addition, IDOL was sequenced in 560 individuals with baseline LDL-C levels below the 20th percentile adjusted for age and gender (low-LDL-C cohort). We identified a total of 14 IDOL variants (5 synonymous, 8 non-synonymous, and 1 non-sense). Functional characterization of these variants demonstrated that the p.Arg266X variant represents a complete loss of IDOL function unable to promote ubiquitylation and subsequent degradation of the LDLR. Consistent with loss of IDOL function, this variant was identified in individuals with low circulating LDL-C. Conclusion Our results support the notion that IDOL contributes to variation in circulating levels of LDL-C. Strategies to inhibit IDOL activity may therefore provide a novel therapeutic venue to treating dyslipidaemia. [ABSTRACT FROM PUBLISHER]

Familial hypercholesterolaemia (FH) is an autosomal dominant genetic disorder, associated with elevated levels of low-density lipoprotein-cholesterol (LDL-C), which can lead to premature cardiovascular disease. Early diagnosis of FH is important to prevent morbidity and mortality. Familial hypercholesterolaemia is usually diagnosed using clinical characteristics, such as family history, and cholesterol levels; however, genetic testing may provide a definite diagnosis of FH by detecting a pathological mutation. Current guidelines highlight the importance of reducing LDL-C levels in patients with FH. Statins are the current standard treatment for the majority of these patients, and have been shown to be effective in reducing the incidence of cardiovascular heart disease in patients with FH. Nevertheless, many FH patients do not achieve their target LDL-C levels; as such, new treatment options are required to decrease LDL-C levels beyond those currently achieved. There are currently several new classes of pharmacotherapy under investigation to control LDL-C levels. These include agents which modify LDL-C production, such as inhibitors of apolipoprotein B, or those which affect LDL-C catabolism, such as inhibition of pro-protein convertase subtilisin/kexin 9, a protein which is responsible for the degradation of the LDL receptor. Therapies which raise high-density lipoprotein cholesterol are also being evaluated. In this article, we consider the diagnosis of FH and the goals of therapy and review the current and potential future treatment options for patients with FH. [ABSTRACT FROM PUBLISHER]

Aims Low HDL-C is a potent risk factor for cardiovascular disease (CVD). Yet, mutations in ABCA1, a major determinant of circulating HDL-C levels, were previously not associated with CVD risk in cohort studies. To study the consequences of low plasma levels of high-density lipoprotein cholesterol (HDL-C) due to ATP-binding cassette transporter A1 (ABCA1) dysfunction for atherosclerotic vascular disease in the carotid arteries. Methods and results We performed 3.0 Tesla magnetic resonance imaging (MRI) measurements of the carotid arteries in 36 carriers of high impact functional ABCA1 mutations and 36 normolipidemic controls. Carriers presented with 42% lower HDL-C levels (P < 0.001), a larger mean wall area (18.6 ± 6.0 vs. 15.8 ± 4.3 mm2; P = 0.02), a larger mean wall thickness (0.82 ± 0.21 vs. 0.70 ± 0.14 mm; P = 0.005), and a higher normalized wall index (0.37 ± 0.06 vs. 0.33 ± 0.04; P = 0.005) compared with controls, retaining significance after adjustment for smoking, alcohol consumption, systolic blood pressure, diabetes, body mass index, history of CVD, LDL-C, and statin use (P = 0.002). Conclusion Carriers of loss of function ABCA1 mutations display a larger atherosclerotic burden compared with age and sex-matched controls, implying a higher risk for CVD. Further studies are needed to elucidate the full function of ABCA1 in the protection against atherosclerosis. These data support the development of strategies to up-regulate ABCA1 in patients with established CVD. [ABSTRACT FROM PUBLISHER]

Aims A plethora of mutations in the LDL-receptor gene (LDLR) underlie the clinical phenotype of familial hypercholesterolaemia (FH). For the diagnosis of FH, it is important, however, to discriminate between pathogenic and non-pathogenic mutations. The aim of the current study was to assess whether true pathogenic mutations were indeed associated with the occurrence of coronary artery disease (CAD) when compared with non-functional variants. The latter variants should not exhibit such an association with CAD. Methods and results We assessed 29 365 individuals tested the 64 most prevalent LDLR variants. First, we determined pathogenicity for each of these sequence variants. Subsequently, a Cox-proportional hazard model was used to compare event-free survival, defined as the period from birth until the first CAD event, between carriers and non-carriers of LDLR mutations. Fifty-four sequence variants in the LDLR gene were labelled as pathogenic and 10 as non-pathogenic. The 9 912 carriers of a pathogenic LDLR mutation had a shorter event-free survival than the 18 393 relatives who did not carry that mutation; hazard ratio 3.64 [95% confidence interval (CI): 3.24–4.08; P< 0.001]. In contrast, the 355 carriers of a non-pathogenic LDLR variant had similar event-free survival as the 705 non-carrying relatives; hazard ratio 1.00 (95% CI: 0.52–1.94; P= 0.999). Conclusion These findings with respect to clinical outcomes substantiate our criteria for functionality of LDLR sequence variants. They also confirm the CAD risk associated with FH and underline that these criteria can be used to decide whether a specific sequence variant should be used in cascade screening. [ABSTRACT FROM PUBLISHER]

Antisense oligonucleotides (ASOs) are short synthetic analogues of natural nucleic acids designed to specifically bind to a target messenger RNA (mRNA) by Watson–Crick hybridization, inducing selective degradation of the mRNA or prohibiting translation of the selected mRNA into protein. Antisense technology has the ability to inhibit unique targets with high specificity and can be used to inhibit synthesis of a wide range of proteins that could influence lipoprotein levels and other targets. A number of different classes of antisense agents are under development. To date, mipomersen, a 2′-O-methoxyethyl phosphorothioate 20-mer ASO, is the most advanced ASO in clinical development. It is a second-generation ASO developed to inhibit the synthesis of apolipoprotein B (apoB)-100 in the liver. In Phase 3 clinical trials, mipomersen has been shown to significantly reduce plasma low-density lipoprotein cholesterol (LDL-c) as well as other atherogenic apoB containing lipoproteins such as lipoprotein (a) [Lp(a)] and small-dense LDL particles. Although concerns have been raised because of an increase in intrahepatic triglyceride content, preliminary data from long-term studies suggest that with continued treatment, liver fat levels tend to stabilize or decline. Further studies are needed to evaluate potential clinical relevance of these changes. Proprotein convertase subtilisin/kexin-9 (PCSK9) is another promising novel target for lowering LDL-c by ASOs. Both second-generation ASOs and ASOs using locked nucleic acid technology have been developed to inhibit PCSK9 and are under clinical development. Other targets currently being addressed include apoC-III and apo(a) or Lp(a). By directly inhibiting the synthesis of specific proteins, ASO technology offers a promising new approach to influence the metabolism of lipids and to control lipoprotein levels. Its application to a wide variety of potential targets can be expected if these agents prove to be clinically safe and effective. [ABSTRACT FROM PUBLISHER]

Subjects with obesity and insulin resistance display a low response to a serotonergic challenge test. One of the hallmarks of obesity and insulin resistance is elevated plasma free fatty acids (FFAs). We hypothesize that increasing plasma FFA by infusion of a lipid emulsion, may be a contributing component leading to decreased serotonergic responsivity in healthy young men. Ten lean healthy men, 23.6 ± 5.0 years and BMI 22.6 ± 1.9 kg/m2, were included. Serotonergic responsivity was assessed using the prolactin response to infusion with citalopram, a selective serotonin reuptake inhibitor, which is a validated tool to assess serotonergic tone. All participants received a lipid/heparin emulsion (Intralipid) infusion during 6 h. Saline infusion was used as a control. To evaluate a possible effect of heparin per se on prolactin, four out of the ten subjects also received heparin only during 6 h without the serotonergic challenge test. Plasma prolactin increased by 74.3 ± 15.5% during saline infusion. Intralipid infusion increased plasma FFA from 0.5 ± 0.05 to 2.3 ± 0.2 mmol/l (p < 0.001). The increase in plasma prolactin during Intralipid infusion was significantly lower (39.3 ± 10%; p < 0.001 compared to saline infusion). Heparin infusion per se increased plasma prolactin by 14.0 ± 1.9%. We found that during the Intralipid infusion with concomitant high plasma FFA levels the serotonergic response was decreased in healthy young men. Higher FFA levels may be the mediator of the decreased serotonergic response reported in patients with insulin resistance and obesity. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aims Autosomal dominant hypercholesterolaemia (ADH) is a major risk factor for coronary artery disease. This disorder is caused by mutations in the genes coding for the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin 9 (PCSK9). However, in 41% of the cases, we cannot find mutations in these genes. In this study, new genetic approaches were used for the identification and validation of new variants that cause ADH. Methods and results Using exome sequencing, we unexpectedly identified a novel APOB mutation, p.R3059C, in a small-sized ADH family. Since this mutation was located outside the regularly screened APOB region, we extended our routine sequencing strategy and identified another novel APOB mutation (p.K3394N) in a second family. In vitro analyses show that both mutations attenuate binding to the LDLR significantly. Despite this, both mutations were not always associated with ADH in both families, which prompted us to validate causality through using a novel genetic approach. Conclusion This study shows that advances in genetics help increasing our understanding of the causes of ADH. We identified two novel functional APOB mutations located outside the routinely analysed APOB region, suggesting that screening for mutations causing ADH should encompass the entire APOB coding sequence involved in LDL binding to help identifying and treating patients at increased cardiovascular risk. [ABSTRACT FROM PUBLISHER]

Aims A randomized, double-blind, placebo-controlled study was conducted to investigate the safety and efficacy of mipomersen, an apolipoprotein B-100 (apoB) synthesis inhibitor, in patients who are statin intolerant and at high risk for cardiovascular disease (CVD). Methods and results Thirty-three subjects, not receiving statin therapy because of statin intolerance, received a weekly subcutaneous dose of 200 mg mipomersen or placebo (2:1 randomization) for 26 weeks. The primary endpoint was per cent change in LDL cholesterol (LDL-c) from the baseline to Week 28. The other efficacy endpoints were per cent change in apoB and lipoprotein a [Lp(a)]. Safety was determined using the incidence of treatment-emergent adverse events (AEs) and clinical laboratory evaluations. After 26 weeks of mipomersen administration, LDL-c was reduced by 47 ± 18% (P < 0.001 vs. placebo). apoB and Lp(a) were also significantly reduced by 46 and 27%, respectively (P < 0.001 vs. placebo). Four mipomersen (19%) and two placebo subjects (17%) discontinued dosing prematurely due to AEs. Persistent liver transaminase increases ≥3× the upper limit of normal were observed in seven (33%) subjects assigned to mipomersen. In selected subjects, liver fat content was assessed, during and after treatment, using magnetic resonance spectroscopy. Liver fat content in these patients ranged from 0.8 to 47.3%. Liver needle biopsy was performed in two of these subjects, confirming hepatic steatosis with minimal inflammation or fibrosis. Conclusion The present data suggest that mipomersen is a potential therapeutic option in statin-intolerant patients at high risk for CVD. The long-term follow-up of liver safety is required. [ABSTRACT FROM PUBLISHER]

Aims High-density lipoprotein cholesterol (HDL-C) is inversely associated with cardiovascular (CV) events and thus an attractive therapeutic target. However, in spite of marked elevations in HDL-C, the first cholesterol transport protein (CETP) inhibitor torcetrapib raised blood pressure (BP), impaired endothelial function, and increased CV mortality and morbidity. Dalcetrapib is a novel molecule acting on CETP with a different chemical structure to torcetrapib. As HDL stimulates nitric oxide (NO), suppresses inflammation, and exerts protective CV effects, we investigated the effects of dalcetrapib on endothelial function, blood pressure, inflammatory markers, and lipids in patients with, or at risk of, coronary heart disease (CHD) in a double-blind randomized placebo-controlled trial (clinicaltrials.gov number NCT00655538). Methods and results Patients with target low-density lipoprotein cholesterol (LDL-C) levels received dalcetrapib 600 mg/day or placebo for 36 weeks on top of standard therapy (including statins). The primary outcome measures were the change from baseline of flow-mediated dilatation (%FMD) of the right brachial artery after 5 min of cuff occlusion at 12 weeks and the 24 h ambulatory blood pressure monitoring (ABPM) at week 4. Secondary outcomes included change from baseline in FMD after 36 weeks and the change in ABPM at 12 and 36 weeks, changes in HDL-C, LDL-C, triglycerides, CETP activity, as well as standard safety parameters. Four hundred seventy-six patients were randomized. Baseline FMD was 4.1 ± 2.2 and 4.0 ± 2.4% with placebo or dalcetrapib, respectively and did not change significantly from placebo after 12 and 36 weeks (P = 0.1764 and 0.9515, respectively). After 4, 24, and 36 weeks of treatment with dalcetrapib, CETP activity decreased by 51, 53, and 56% (placebo corrected, all P < 0.0001), while at weeks 4, 12, and 36 HDL-C increased by 25, 27, and 31% (placebo corrected, all P < 0.0001). Low-density lipoprotein cholesterol levels did not change. At baseline, ABPM was 125 ± 12/74 ± 8mmHg in the placebo and 128 ± 11/75 ± 7mmHg in the dalcetrapib group (P = 0.3372 and 0.1248, respectively, placebo-corrected change from baseline) and did not change for up to 36 weeks. Biomarkers of inflammation, oxidative stress, and coagulation did not change during follow-up except for Lp-PLA2 mass levels which increased by 17% (placebo corrected). Overall 7 patients given dalcetrapib and 8 patients given placebo experienced at least one pre-specified adjudicated event (11 events with dalcetrapib and 12 events with placebo). Conclusion The dal-VESSEL trial has established the tolerability and safety of CETP-inhibition with dalcetrapib in patients with or at risk of CHD. Dalcetrapib reduced CETP activity and increased HDL-C levels without affecting NO-dependent endothelial function, blood pressure, or markers of inflammation and oxidative stress. The dal-OUTCOMES trial (NCT00658515) will show whether dalcetrapib improves outcomes in spite of a lack of effect on endothelial function. [ABSTRACT FROM PUBLISHER]

The article discusses a study on the association between several biomarkers with cardiovascular risk among patients treated with statins. The biomarkers investigated were low-density lipoprotein cholesterol (LDL-C), non-high density lipoprotein cholesterol (non-HDL-C) and apolipoprotein B (apoB). The study searched literature to identify randomized controlled trials (RCTs) involving patients assigned to statin therapy. It was found that fatal and nonfatal myocardial infarctions, fatal events from other coronary artery disease, hospitalizations for unstable angina and fatal or nonfatal strokes occurred among patients treated with statins. The study showed that non-HDL-C had greater association with cardiovascular risk compared with LDL-C and apoB.

Autosomal Dominant Hypercholesterolemia (ADH) is caused by LDLR and APOB mutations. However, genetically diagnosed ADH patients do not always exhibit the expected hypercholesterolemic phenotype. Of 4,669 genetically diagnosed ADH patients, identified through the national identification screening program for ADH, 75 patients (1.6%) had LDL-cholesterol (LDL-C) levels below the 50th percentile for age and gender prior to lipid-lowering therapy. The genes encoding APOB, PCSK9, and ANGPTL3 were sequenced in these subjects to address whether monogenic dominant loss-of-function mutations underlie this paradoxical phenotype. APOB mutations, resulting in truncated APOB, were found in five (6.7%) probands, reducing LDL-C by 56%. Rare variants in PCSK9, and ANGPTL3 completely correcting the hypercholesterolemic phenotype were not found. The common variants p.N902N, c.3842+82T>A, p.D2312D, and p.E4181K in APOB, and c.1863+94A>G in PCSK9 were significantly more prevalent in our cohort compared to the general European population. Interestingly, 40% of our probands carried at least one minor allele for all four common APOB variants compared to 1.5% in the general European population. While we found a low prevalence of rare variants in our cohort, our data suggest that regions in proximity of the analyzed loci, and linked to specific common haplotypes, might harbor additional variants that correct an ADH phenotype. Hum Mutat 33:448-455, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Lecithin:cholesterol acyltransferase (LCAT) is crucial to the maturation of high-density lipoprotein (HDL). Homozygosity for LCAT mutations underlies rare disorders characterized by HDL-cholesterol (HDL-c) deficiency while heterozygotes have half normal HDL-c levels. We studied the prevalence of LCAT mutations in referred patients with low HDL-c to better understand the molecular basis of low HDL-c in our patients. LCAT was sequenced in 98 patients referred for HDL-c <5th percentile and in four patients referred for low HDL-c and corneal opacities. LCAT mutations were highly prevalent: in 28 of the 98 participants (29%), heterozygosity for nonsynonymous mutations was identified while 18 patients carried the same mutation (p.T147I). The four patients with corneal opacity were compound heterozygotes. All previously identified mutations are documented to cause loss of catalytic activity. Nine novel mutations-c.402G>T (p.E134D), c.403T>A (p.Y135N), c.964C>T (p.R322C), c.296G>C (p.W99S), c.736G>T (p.V246F), c.802C>T (p.R268C), c.945G>A (p.W315X), c.1012C>T (p.L338F), and c.1039C>T (p.R347C)--were shown to be functional through in vitro characterization. The effect of several mutations on the core protein structure was studied by a three-dimensional (3D) model. Unlike previous reports, functional mutations in LCAT were found in 29% of patients with low HDL-c, thus constituting a common cause of low HDL-c in referred patients in The Netherlands. Hum Mutat 32:1290-1298, 2011. ©2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Aims Mipomersen, an apolipoprotein (apo) B synthesis inhibitor, has been shown to produce potent reductions in apoB and LDL-cholesterol levels in animal models as well as healthy human volunteers. A randomized, double-blind, placebo-controlled, dose-escalation study was designed to evaluate the efficacy and safety of mipomersen monotherapy with or without dose loading in subjects with mild-to-moderate hyperlipidaemia. Methods and results Fifty subjects with LDL-cholesterol levels between 119 and 266 mg/dL were enrolled into five cohorts at a 4:1 randomization ratio of active to placebo. Two 13-week dose regimens were evaluated at doses ranging from 50 to 400 mg/week. Mipomersen produced dose-dependent reductions in all apoB containing lipoproteins. In the 200 and 300 mg/week dose cohorts, mean reductions from baseline in LDL cholesterol were −45 ± 10% (P= 0.000) and −61 ± 8% (P= 0.000), corresponding to a −46 ± 11% (P= 0.000) and −61 ± 7% (P= 0.000) decrease in apoB levels. Triglyceride levels were also lowered with median reductions up to 53% (P= 0.021). The most common adverse events were injection site reactions. Seven of 40 subjects (18%) showed consecutive trans-aminase elevations >3× upper limit of normal. Five of these subjects received 400 mg/week, four of whom had apoB levels below the limit of detection. As a consequence, the 400 mg/week cohort was discontinued. Conclusions Mipomersen administered as monotherapy in subjects with mild-to-moderate hyperlipidaemia produced potent reductions in all apoB-containing lipoproteins. Higher doses were associated with hepatic trans-aminase increases. [ABSTRACT FROM PUBLISHER]

Aims Statins are essential for the reduction of risk of coronary heart disease (CHD) in familial hypercholesterolemia (FH). One of many genes influenced by statin treatment is the ATP-binding cassette transporter A1 (ABCA1) gene, which plays an important role in metabolism of high-density lipoprotein (HDL). The present aim was to test if the ABCA1 C69T polymorphism influences CHD risk and response to statin treatment. Methods and results In a large cohort of 1686 FH patients without a history of CHD before 1 January 1990, we analysed statin-ABCA1 C69T polymorphism interaction by comparing treated and untreated patients. We used a Cox proportional hazard model adjusted for sex, birth year, and smoking. In analyses restricted to untreated patients, the TT genotype was associated with 1.7 times higher CHD risk than the CC genotype (hazard ratio (HR) =1.65, 95% confidence interval (95% CI): 1.08–2.53; P = 0.02). Conversely, in statin-treated FH patients, CHD risk in TT individuals was not increased (HR: 0.65, 95% CI: 0.35–1.24; P = 0.2). Formal testing confirmed this interaction (P = 0.03). HDL-cholesterol levels were significantly more raised in statin-treated patients with the TT than with the CC genotype (two-way ANOVA, P = 0.045). Conclusion In untreated FH patients, the TT genotype of the ABCA1 C69T polymorphism was associated with increased CHD risk. However, in statin-treated patients, CHD risk was no longer significantly different between genotypes, at least partially explained by a higher rise in HDL-cholesterol levels during statin treatment in TT individuals. [ABSTRACT FROM PUBLISHER]

Aims The aim of this study was to determine the contribution of physical activity and abdominal obesity to the variation in inflammatory biomarkers and incident coronary heart disease (CHD) in a European population. Methods and results In a prospective case–control study nested in the European Prospective Investigation into Cancer and Nutrition-Norfolk cohort, we examined the associations between circulating levels or activity of C-reactive protein, myeloperoxidase (MPO), secretory phospholipase A2 (sPLA2), lipoprotein-associated phospholipase A2 (Lp-PLA2), fibrinogen, adiponectin, waist circumference, physical activity, and CHD risk over a 10-year period among healthy men and women (45–79 years of age). A total of 1002 cases who developed fatal or non-fatal CHD were matched to 1859 controls on the basis of age, sex, and enrolment period. Circulating levels of C-reactive protein, sPLA2 (women only), fibrinogen, and adiponectin were linearly associated with increasing waist circumference and decreasing physical activity levels. After adjusting for waist circumference, physical activity, smoking, diabetes, systolic blood pressure, low-density lipoprotein and high-density lipoprotein cholesterol levels, and further adjusted for hormone replacement therapy in women, C-reactive protein, MPO (men only), sPLA2, fibrinogen, but not Lp-PLA2 and adiponectin were associated with an increased CHD risk. Conclusion Inactive participants with an elevated waist circumference were characterized by deteriorated levels of inflammatory markers. However, several inflammatory markers were associated with an increased CHD risk, independent of underlying CHD risk factors such as waist circumference and physical activity levels. [ABSTRACT FROM PUBLISHER]

Evidence suggests that endothelial dysfunction is on the causal pathway for both atherogenesis and destabilization of established plaques. In this review, the role of flow-mediated dilatation (FMD) as a non-invasive method to assess endothelial function is discussed. Technical modifications and development of analysis software have significantly improved the variability of the method. Following a strict standardized protocol enables reproducible measurements to be achieved and export of the technique from specialized laboratories to population studies and multicentre settings. Endothelial function assessed by FMD has been shown to be affected by cardiovascular risk factors, to be related to structural arterial disease and to cardiovascular outcome, validating its use for studying the pathophysiology of arterial disease. Numerous studies have also demonstrated that it is responsive to physiological and pharmacological interventions. Flow-mediated dilatation provides unique opportunities in drug development programmes to assess an early rapidly responsive signal of risk or benefit, complementing endpoints of structural arterial disease and cardiovascular outcomes that take much longer and are more expensive. [ABSTRACT FROM PUBLISHER]

C-reactive protein is postulated to embody an index that can reflect cardiovascular risk and can be used to independently predict major cardiovascular events and mortality. On the other hand, credible experimental data have become available that demonstrate the abundant presence of C-reactive protein in atherosclerotic lesions and, moreover, identify C-reactive protein as an initiator of several pathogenic pathways that can cause atherogenic changes. Consequently, there has been a paradigm shift in which C-reactive protein is no longer regarded as merely an indicator of cardiovascular risk, but increasingly considered a direct partaker in the pathogenesis of atherosclerotic cardiovascular disease. These data underscore the need to explore risk-reducing interventions that selectively inhibit C-reactive protein activity as a novel strategy to prevent clinical manifestations of atherosclerosis. [ABSTRACT FROM PUBLISHER]

Abstract: Ezetimibe stimulates faecal neutral sterol (FNS) excretion in mice, which cannot be explained by cholesterol absorption inhibition alone. We investigated whether these effects are mediated via the sterol exporter ATP binding cassette transporter G8 (abcg8). Ezetimibe increased FNS excretion 2.7-fold in WT mice and 1.5-fold in abcg8−/− mice, without affecting biliary cholesterol secretion. Daily FNS excretion exceeded the sum of dietary cholesterol intake and biliary secretion by about 60%. Ezetimibe enhanced this ‘extra’ FNS excretion by 3.5-fold and 1.5-fold in wildtype (WT) and abcg8−/− mice, respectively. Ezetimibe stimulates fecal sterol excretion of non-biliary and non-dietary origin, probably through stimulation of trans-intestinal cholesterol excretion. We show that this effect depends on intact abcg8 function. [ABSTRACT FROM AUTHOR]

Patients with familial hypercholesterolemia (FH) have elevated LDL-C levels, usually above the 90th percentile (P90) for age and gender. However, large-scale genetic cascade screening for FH showed that 15% of the LDL-receptor (LDLR) or Apolipoprotein B (APOB) mutation carriers have LDL-C levels below P75. Nonpathogenicity of sequence changes may explain this phenomenon. To assess pathogenicity of a mutation we proposed three criteria: (1) mean LDL-C >P75 in untreated mutation carriers; (2) higher mean LDL-C level in untreated carriers than in untreated noncarriers; and (3) higher percentage of medication users in carriers than in noncarriers at screening. We considered a mutation nonpathogenic when none of the three criteria were met. We applied these criteria to mutations that had been determined in more than 50 untreated adults. Segregation analysis was performed to confirm nonpathogenicity. Forty-six mutations had been tested in more than 50 untreated subjects, and three were nonpathogenic according to our criteria: one in LDLR (c.108C>A, exon 2) and two in APOB (c.13154T>C and c.13181T>C, both in exon 29). Segregation analysis also indicated nonpathogenicity. According to our criteria, three sequence variants were nonpathogenic. The criteria may help to identify nonpathogenic sequence changes in genetic cascade screening programs. Hum Mutat 31:752-760, 2010. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Aims: The presence of tendon xanthomas is a marker of high risk of cardiovascular disease (CVD) among patients with familial hypercholesterolaemia (FH). Therefore, xanthomas and atherosclerosis may result from the same pathophysiological mechanisms. Reverse cholesterol transport (RCT) and low-density lipoprotein (LDL) oxidation are pathophysiological pathways of atherosclerosis, and it is well established that genetic variation in these pathways influences CVD risk. We therefore determined whether genetic variation in these pathways is also associated with the occurrence of tendon xanthomas in FH patients. [ABSTRACT FROM PUBLISHER]

This article reports on a study that examined coronary disease in patients with abdominal obesity and the effect of the selective cannabinoid type 1 receptor antagonist rimonabant on slowing the progression of heart disease. Through a randomized controlled trial patients received either rimonabant or a placebo and underwent coronary intravascular ultrasonography at the beginning and end of the trial. The article discusses the results of the trial and the conclusion that rimonabant had a favorable effect on patients at the secondary endpoint of the study. The article also notes that more imaging and outcomes trials are necessary.

Aims To investigate the influence of different LDL-receptor (LDLR) gene mutations on age at first cardiovascular event in familial hypercholesterolaemia (FH) patients. [ABSTRACT FROM PUBLISHER]

Aims To investigate the ‘real world’ effectiveness of robust statin therapy, focusing on the effect of dose and early treatment discontinuation on the risk of hospitalization for acute myocardial infarction (AMI). [ABSTRACT FROM PUBLISHER]

Aims We assembled a cohort of patients with familial hypercholesterolaemia (FH) for both basic and clinical research. We used a set of established diagnostic criteria to define FH. Some put forward that a definite diagnosis of FH is made when a mutation in the LDL-receptor (LDLR) gene is identified. We therefore set out to determine in these patients whether patients with a DNA diagnosis would differ significantly from those diagnosed clinically. [ABSTRACT FROM PUBLISHER]

Abstract: Atherosclerosis is characterized by a persistent, low-grade inflammatory state in which immune cell activation is inseparably linked to plaque formation and destabilization. The T-lymphocyte in particular has emerged as a pivotal player throughout the course of atherogenesis. As a consequence, the concept that immune modulation is a suitable target for cardiovascular prevention is currently an important focus of research. Mycophenolate mofetil (MMF) has emerged as a non-competitive inhibitor of inosine monophosphate dehydrogenase (IMPDH) that exerts cytostatic effects, particularly on proliferating T-lymphocytes. In addition, MMF has other immune-modulating effects, such as downregulation of the expression of adhesion molecules and attenuation of monocyte and macrophage responses. Given the added benefit that MMF is well tolerated, this immunosuppressive agent constitutes an attractive candidate for the modulation of inflammatory activation in atherogenesis. The present review provides an overview of the potential anti-atherogenic properties of MMF. [Copyright &y& Elsevier]

Autosomal-dominant hypercholesterolemia (ADH) has been identified as a major risk factor for coronary vascular disease (CVD) and is associated with mutations in the low-density lipoprotein receptor ( LDLR) and the apolipoprotein B ( APOB) gene. Since 1991 DNA samples from clinically diagnosed ADH patients have been routinely analyzed for the presence of LDLR and APOB gene mutations. As of 2001, 1,641 index patients (164 index patients per year) had been identified, while from 2001 onward a more sensitive, high-throughput system was used, resulting in the identification of 1,177 new index patients (average=294 index patients per year). Of these 1,177 index cases, 131 different causative genetic variants in the LDLR gene and six different causative mutations in the APOB gene were new for the Dutch population. Of these 131 mutations, 83 LDLR and four APOB gene mutations had not been reported before. The inclusion of all 2,818 index cases into the national screening program for familial hypercholesterolemia (FH) resulted in the identification of 7,079 relatives who carried a mutation that causes ADH. Screening of the LDLR and APOB genes in clinically diagnosed FH patients resulted in approximately 77% of the patients being identified as carriers of a causative mutation. The population of patients with ADH was divided into three genetically distinct groups: carriers of an LDLR mutation (FH), carriers of an APOB mutation (FDB), and non- LDLR/non- APOB patients (FH3). No differences were found with regard to untreated cholesterol levels, response to therapy, and onset of CVD. However, all groups were at an increased risk for CVD. Therefore, to ultimately identify all individuals with ADH, the identification of new genes and mutations in the genes that cause ADH is of crucial importance for the ongoing national program to identify patients with ADH by genetic cascade screening. Hum Mutat 26(6), 550-556, 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]