Serum bilirubin levels in familial hypercholesterolemia: a new risk marker for cardiovascular disease?

Low concentrations of bilirubin are associated with an increased risk for cardiovascular disease (CVD). Possibly, bilirubin exerts its effect through the protection of LDL from oxidation. Therefore, we examined whether low bilirubin might also be a risk marker for CVD in patients with familial hypercholesterolemia (FH) and whether statins influence serum bilirubin levels. Patients with FH were recruited from 37 lipid clinics. After a washout period of 6 weeks, all patients were started on monotherapy with simvastatin 80 mg for a period of two years. A total of 514 patients were enrolled. Bilirubin at baseline was inversely associated with the presence of CVD, also after adjustment for age, gender, presence of hypertension, and HDL cholesterol levels. Moreover, bilirubin levels were significantly raised, by 7%, from 10.0 to 10.8 μmol/L after treatment with simvastatin 80 mg. We hypothesize first that high bilirubin levels might protect patients with FH from CVD. Furthermore, bilirubin levels were significantly increased after treatment with simvastatin 80 mg, independent of changes in liver enzymes, which might confer additional protection against CVD. Whether this is also true for lower doses of simvastatin or for other statins remains to be investigated.

Risk of incident diabetes with intensive-dose compared with moderate-dose statin therapy: a meta-analysis

CONTEXT

A recent meta-analysis demonstrated that statin therapy is associated with excess risk of developing diabetes mellitus.

OBJECTIVE

To investigate whether intensive-dose statin therapy is associated with increased risk of new-onset diabetes compared with moderate-dose statin therapy.

DATA SOURCES

We identified relevant trials in a literature search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (January 1, 1996, through March 31, 2011). Unpublished data were obtained from investigators.

STUDY SELECTION

We included randomized controlled end-point trials that compared intensive-dose statin therapy with moderate-dose statin therapy and included more than 1000 participants who were followed up for more than 1 year.

DATA EXTRACTION

Tabular data provided for each trial described baseline characteristics and numbers of participants developing diabetes and experiencing major cardiovascular events (cardiovascular death, nonfatal myocardial infarction or stroke, coronary revascularization). We calculated trial-specific odds ratios (ORs) for new-onset diabetes and major cardiovascular events and combined these using random-effects model meta-analysis. Between-study heterogeneity was assessed using the I(2) statistic.

RESULTS

In 5 statin trials with 32,752 participants without diabetes at baseline, 2749 developed diabetes (1449 assigned intensive-dose therapy, 1300 assigned moderate-dose therapy, representing 2.0 additional cases in the intensive-dose group per 1000 patient-years) and 6684 experienced cardiovascular events (3134 and 3550, respectively, representing 6.5 fewer cases in the intensive-dose group per 1000 patient-years) over a weighted mean (SD) follow-up of 4.9 (1.9) years. Odds ratios were 1.12 (95% confidence interval [CI], 1.04-1.22; I(2) = 0%) for new-onset diabetes and 0.84 (95% CI, 0.75-0.94; I(2) = 74%) for cardiovascular events for participants receiving intensive therapy compared with moderate-dose therapy. As compared with moderate-dose statin therapy, the number needed to harm per year for intensive-dose statin therapy was 498 for new-onset diabetes while the number needed to treat per year for intensive-dose statin therapy was 155 for cardiovascular events.

CONCLUSION

In a pooled analysis of data from 5 statin trials, intensive-dose statin therapy was associated with an increased risk of new-onset diabetes compared with moderate-dose statin therapy.

Efficacy of apolipoprotein B synthesis inhibition in subjects with mild-to-moderate hyperlipidaemia

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 transaminase 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 transaminase increases.

Prediction of cardiovascular events in statin-treated stable coronary patients by lipid and nonlipid biomarkers

OBJECTIVES

The aim of this study was to investigate the relationship between lipid and nonlipid biomarker levels achieved during statin therapy and the incidence of major cardiovascular events (MCVEs) in patients with stable coronary heart disease (CHD).

BACKGROUND

Several plasma nonlipid biomarkers have been shown to predict MCVEs in population studies.

METHODS

This is a nested case-control study in the TNT (Treating to New Targets) study population, a randomized trial that compared the efficacy of high- (80 mg) versus low-dose (10 mg) atorvastatin for the secondary prevention of CHD. Fasting plasma levels of standard lipids and of 18 nonlipid biomarkers were obtained after an 8-week run-in period on atorvastatin 10 mg and again 1 year after being randomized to 10 or 80 mg atorvastatin in 507 patients who experienced MCVEs during the 4.9 years of study follow-up and in 1,020 control subjects. An MCVE was defined as CHD death; nonfatal, non-procedure-related myocardial infarction; resuscitated cardiac arrest; or fatal or nonfatal stroke.

RESULTS

Low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides were all predictive of recurrent MCVEs (p ≤ 0.009). Concentrations of many of the 18 nonlipid biomarkers were lowered by atorvastatin therapy (independent of dose). However, almost none of the nonlipid biomarker levels, whether measured after the 8-week run-in period or after 1 year of treatment with 10 or 80 mg atorvastatin, were predictive of recurrent MCVEs.

CONCLUSIONS

In patients with stable CHD, atorvastatin improved plasma levels of an expanded panel of nonlipid biomarkers. However, independently of atorvastatin dose, the achieved levels of the vast majority of nonlipid biomarkers did not predict MCVEs. (A Study to Determine the Degree of Additional Reduction in CV Risk in Lowering LDL Below Minimum Target Levels [TNT]; NCT00327691).

LDL cholesterol goals and cardiovascular risk during statin treatment: the IDEAL study

AIMS

We assessed the proportion of patients treated with either simvastatin 20 or 40 mg or atorvastatin 80 mg who achieved low-density lipoprotein cholesterol (LDL-C) goals of 2.5 or 2.0 mmol/l in the Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) study. We explored how lipoprotein components related to cardiovascular disease (CVD) outcomes in these groups.

METHODS AND RESULTS

For subjects who reached on-treatment LDL-C goals, Cox regression models were used to assess the ability of lipoprotein components to predict CVD events. Treatment with simvastatin or atorvastatin resulted in 40 per cent and 80 per cent of patients, respectively, reaching the 2.5 mmol/l goal and 12 per cent and 52 per cent, respectively, reaching the 2.0 mmol/l goal, after 1 year (all p < 0.001 between groups). Adjusting for baseline LDL-C levels, hazard ratio (HR) for those reaching 2.0-2.5 mmol/l LDL-C versus those reaching <2.0 mmol/l was 1.16 (95% confidence interval [CI], 1.02-1.33, p = 0.023). An increase of the apolipoprotein B/A1 (apoB/A1) ratio by 1 standard deviation in participants who reached 2.0 mmol/l showed a HR for CVD of 1.14 (95% CI, 1.04-1.25, p = 0.004).

CONCLUSION

More CVD patients treated with atorvastatin than simvastatin achieved either LDL-C goal and those reaching the 2.0 mmol/l goal exhibited significantly less CVD than those only reaching 2.5 mmol/l. In those reaching the 2.0 mmol/l goal, the apoB/A1 ratio still bears a relation to CVD outcome. The use of apoB/A1 ratio may provide additional predictive value to that of LDL-C.

The prolactin receptor is expressed in macrophages within human carotid atherosclerotic plaques: a role for prolactin in atherogenesis?

Atherosclerotic vascular disease is the consequence of a chronic inflammatory process, and prolactin has been shown to be a component of the inflammatory response. Additionally, recent studies indicate that prolactin contributes to an atherogenic phenotype. We hypothesized that this may be the result of a direct effect of prolactin on atherogenesis through activation of the prolactin receptor. Human carotid atherosclerotic plaques were obtained from patients by endarteriectomies. The mRNA of prolactin receptor, but not of prolactin, was detected in these atherosclerotic plaques by quantitative real-time PCR. In situ hybridization confirmed the expression of the prolactin receptor in mononuclear cells. Analysis at the protein level using immunohistochemistry and immunoelectron microscopy revealed that the prolactin receptor was abundantly present in macrophages near the lipid core and shoulder regions of the plaques. Our findings demonstrate that the prolactin receptor is present in macrophages of the atherosclerotic plaque at sites of most prominent inflammation. We therefore propose that prolactin receptor signaling contributes to the local inflammatory response within the atherosclerotic plaque and thus to atherogenesis.

On-treatment lipoprotein components and risk of cerebrovascular events in the Treating to New Targets study

BACKGROUND

The Treating to New Targets (TNT) study has recently provided evidence that reduction in LDL-C levels below 2·6 mmol L⁻¹ lowers the risk of cerebrovascular events by an additional 20% to 25%, thereby confirming the value of statin therapy in preventing transient ischaemic attacks and stroke. Despite the protective effects of statin therapy, the epidemiological association between lipid components and cerebrovascular events is less clear. We therefore assessed the strength of association between in-trial lipoprotein components and cerebrovascular disease in patients receiving intensive lipid-lowering therapy.

METHODS

In 9247 patients (mean age 61·0 years, 81·2% males), the association between lipoprotein components and the risk of cerebrovascular events after the first year into the TNT trial was assessed after stratification of lipoprotein components into approximate quartiles. Cox proportional hazards models were used to explore the association between lipoprotein components and time to first cerebrovascular event after adjustment for potential confounding variables.

RESULTS

All lipoprotein components, except LDL-C, showed a significant gradient for incidence of cerebrovascular events with increasing quartiles of the lipoprotein component. If the lipoprotein components were treated as continuous variables, the adjusted hazard ratios (95% CI) for cerebrovascular events for 1 SD difference in 1-year lipoprotein components were 1·13 (1·02-1·25) for LDL-C, 0·86 (0·76-0·97) for HDL-C, 1·17 (1·04-1·28) for apoB, 0·83 (0·74-0·94) for apoA-1, 1·22 (1·10-1·34) for TC/HDL-C and 1·24 (1·12-1·37) for apoB/apoA-1.

CONCLUSIONS

In coronary heart disease patients receiving intensive lipid-lowering treatment, the on-treatment apoB/apoA-1 ratio provides the strongest association with incidence of cerebrovascular events followed by TC/HDL-C.

Proteinuria in early childhood due to familial LCAT deficiency caused by loss of a disulfide bond in lecithin:cholesterol acyl transferase

INTRODUCTION

Familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD) is a rare recessive disorder of cholesterol metabolism characterized by the absence of high density lipoprotein (HDL) and the triad of corneal opacification, hemolytic anemia and glomerulopathy.

PATIENTS

We here report on FLD in three siblings of a kindred of Moroccan descent with HDL deficiency. In all cases (17, 12 and 3 years of age) corneal opacification and proteinuria were observed. In the 17-year-old female proband, anemia with target cells was observed.

RESULTS

Homozygosity for a mutation in LCAT resulted in the exchange of cysteine to tyrosine at position 337, disrupting the second disulfide bond in LCAT. LCAT protein and activity were undetectable in the patients' plasma and in media of COS7 cells transfected with an expression vector with mutant LCAT cDNA. Upon treatment with an ACE inhibitor and a thiazide diuretic, proteinuria in the proband decreased from 6g to 2g/24h.

CONCLUSION

This is the first report that FLD can cause nephropathy at a very early age.

Efficacy and safety of a novel oral inducer of apolipoprotein a-I synthesis in statin-treated patients with stable coronary artery disease a randomized controlled trial

OBJECTIVES

The purpose of this study was to investigate the safety, tolerability, and efficacy of RVX-208, the first oral agent designed to enhance apolipoprotein (apo) A-I synthesis.

BACKGROUND

No agent that selectively induces synthesis of apoA-I has reached an advanced stage of clinical development.

METHODS

A total of 299 statin-treated patients with coronary artery disease were treated with placebo or with RVX-208 at a dose of 50, 100, or 150 mg twice daily for 12 weeks. Changes in lipid-related biomarkers, in addition to safety and tolerability, of RVX-208 were investigated.

RESULTS

For each dose of RVX-208, individual pairwise comparisons of apoA-I changes with placebo, the primary end point, did not achieve statistical significance. However, treatment with RVX-208 was associated with a dose-dependent increase in apoA-I levels by up to 5.6% (p = 0.035 for trend). Administration of RVX-208 resulted in significant increases in levels of high-density lipoprotein cholesterol (HDL-C) ranging from 3.2% to 8.3% (p = 0.02), and large HDL particles increased by 11.1% to 21.1% (p = 0.003). ApoA-I levels increased rapidly from 8 to 12 weeks, suggesting that peak pharmacological effect has not been achieved by the end of the 12-week study. Transient and reversible elevations in liver transaminases >3 times the upper limit of normal were observed in 18 patients treated with RVX-208, with no associated increase in bilirubin levels.

CONCLUSIONS

Administration of RVX-208 for 12 weeks was associated with increases in apoA-I, HDL-C, and concentration of large HDL particles, consistent with facilitation of cholesterol mobilization. Maximal increases in apoA-I may require longer exposure. An increase in liver enzymes was observed with active treatment. (Clinical Trial for Dose Finding and Safety of RVX000222 in Subjects With Stable Coronary Artery Disease; NCT01058018).

Genetic variant of the scavenger receptor BI in humans

BACKGROUND

In mice, the scavenger receptor class B type I (SR-BI) is essential for the delivery of high-density lipoprotein (HDL) cholesterol to the liver and steroidogenic organs. Paradoxically, elevated HDL cholesterol levels are associated with increased atherosclerosis in SR-BI-knockout mice. It is unclear what role SR-BI plays in human metabolism.

METHODS

We sequenced the gene encoding SR-BI in persons with elevated HDL cholesterol levels and identified a family with a new missense mutation (P297S). The functional effects of the P297S mutation on HDL binding, cellular cholesterol uptake and efflux, atherosclerosis, platelet function, and adrenal function were studied.

RESULTS

Cholesterol uptake from HDL by primary murine hepatocytes that expressed mutant SR-BI was reduced to half of that of hepatocytes expressing wild-type SR-BI. Carriers of the P297S mutation had increased HDL cholesterol levels (70.4 mg per deciliter [1.8 mmol per liter], vs. 53.4 mg per deciliter [1.4 mmol per liter] in noncarriers; P<0.001) and a reduced capacity for efflux of cholesterol from macrophages, but the carotid artery intima-media thickness was similar in carriers and in family noncarriers. Platelets from carriers had increased unesterified cholesterol content and impaired function. In carriers, adrenal steroidogenesis was attenuated, as evidenced by decreased urinary excretion of sterol metabolites, a decreased response to corticotropin stimulation, and symptoms of diminished adrenal function.

CONCLUSIONS

We identified a family with a functional mutation in SR-BI. The mutation carriers had increased HDL cholesterol levels and a reduction in cholesterol efflux from macrophages but no significant increase in atherosclerosis. Reduced SR-BI function was associated with altered platelet function and decreased adrenal steroidogenesis. (Funded by the European Community and others.).

Rationale and design of dal-VESSEL: a study to assess the safety and efficacy of dalcetrapib on endothelial function using brachial artery flow-mediated vasodilatation

OBJECTIVE

Dalcetrapib increases high-density lipoprotein cholesterol (HDL-C) levels through effects on cholesteryl ester transfer protein (CETP). As part of the dalcetrapib dal-HEART clinical trial programme, the efficacy and safety of dalcetrapib is assessed in coronary heart disease (CHD) patients in the dal-VESSEL study (ClinicalTrials.gov identifier: NCT00655538), the design and methods of which are presented here. RESEARCH DESIGN AND STUDY METHOD: Men and women with CHD or CHD risk equivalent, with HDL-C levels <50  mg/dL were recruited for a 36-week, double-blinded, placebo-controlled trial. After a pre-randomisation phase of up to 8 weeks, patients received dalcetrapib 600  mg/day or placebo in addition to their existing treatments. Brachial flow-mediated dilatation (FMD) measured by B-mode ultrasound represents endothelial function and is a validated marker for early atherosclerosis and cardiovascular disease risk.

MAIN OUTCOME MEASURES

The primary efficacy outcome is change from baseline in brachial FMD after 12 weeks. The primary safety endpoint is 24-hour ambulatory blood pressure monitoring (ABPM) assessed at week 4. Secondary endpoints include brachial FMD at 36 weeks, ABPM at 12 and 36 weeks, lipid profile, CETP mass and activity, and markers of inflammation, oxidation, and cardiovascular risk. Clinical endpoints are assessed as a composite endpoint for the dal-HEART Program.

CURRENT STATUS

In 19 European clinical centres, 476 subjects met inclusion criteria and have entered the study. In conclusion, the dal-VESSEL study is the largest multicentre trial with brachial FMD ever performed. The study assesses efficacy and safety of dalcetrapib on endothelial function, blood pressure, lipids, and clinical outcomes in CHD patients with below average HDL-C and will therefore provide vital information regarding its potential role in the preventative treatment of CHD risk.

Apolipoprotein A-I mimetic peptides

PURPOSE OF REVIEW

To review published data related to the potential applicability of apolipoprotein A-I mimetic peptides.

RECENT FINDINGS

Despite a wealth of information on HDL-C levels and risk for cardiovascular disease (CVD), little evidence is present to suggest that raising HDL-C levels per se will result in CVD risk reduction. Rather, increasing HDL functionality might be a more successful strategy to reverse the process of atherosclerosis. In as such, apoA-I mimetic peptides, either in single or tandem formulation, hold great promise. Evidence gathered over the last years has provided insight in the extent to which mimetics influence several cardio metabolic pathways. ApoA-I mimetics have shown to have anti-inflammatory, antioxidant, and antiatherogenic effects. Direct comparisons between different mimetics have provided insight in factors influencing the differential beneficial consequences of these peptides. Data derived from recent studies suggest that mimetics might gain their position as a therapeutic intervention in the treatment of septicaemia, transplantation rejection, diabetes and auto-immune diseases.

SUMMARY

This review provides a summary of the current literature on the potential application of apoA-I mimetics as therapeutic agents. There is increasing evidence that these mimetics should be considered as a promising supplement to current strategies. Results from human studies addressing the in-vivo effects of the different apoA-I mimetics are eagerly awaited.

Lipid assessment, metabolic syndrome and coronary heart disease risk

BACKGROUND

Although the total to high-density lipoprotein cholesterol ratio (TC/HDL-C) has been used for decades to identify individuals at risk for coronary heart disease (CHD), apolipoprotein-based (apolipoprotein B/apolipoprotein A-I [apoB/apoA-I]) and nuclear magnetic resonance spectroscopy (NMR)-based lipoprotein concentrations (low-density lipoprotein(NMR) /high-density lipoprotein(NMR) [LDL(NMR) /HDL(NMR)]) may also be useful for CHD risk stratification.

MATERIALS AND METHODS

In a case-control study conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study population, 870 individuals who developed CHD during a 6-year follow-up were matched to 1659 controls on the basis of gender, age and enrollment time. LDL(NMR) and HDL(NMR) were measured by proton NMR spectroscopy.

RESULTS

After adjusting for traditional CHD risk factors, men in the top quintile of the various lipoprotein ratios proved to be at increased CHD risk (OR = 2·59 [95% IC, 1·76-3·83] for TC/HDL-C ratio, 2·59 [1·75-3·83] for apoB/apoA-I ratio and 2·78 [1·86-4·17] for LDL(NMR) /HDL(NMR) ratio) compared with men in the bottom quintile. Similar associations were observed in women (OR = 2·86 [1·71-4·80] for TC/HDL-C ratio, 2·94 [1·74-4·97] for apoB/apoA-I ratio and 2·03 [1·21-3·43] for LDL(NMR)/HDL(NMR) ratio). Compared with participants with only one component of the metabolic syndrome, those who had five had an increased TC/HDL-C ratio (73·0% and 80·4% in men and women respectively), apoB/apoA-I ratio (58·0% and 62·9% in men and women respectively) and for LDL(NMR)/HDL(NMR) ratio (52·6% and 54·1% in men and women respectively).

CONCLUSION

In this European study population, the TC/HDL-C, apoB/apoA-I and LDL(NMR) /HDL(NMR) ratios were similarly associated with components of the metabolic syndrome and CHD risk.

Family history of premature coronary heart disease and risk prediction in the EPIC-Norfolk prospective population study

OBJECTIVE

The value of a family history for coronary heart disease (CHD) in addition to established cardiovascular risk factors in predicting an individual's risk of CHD is unclear. In the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort, the authors tested whether adding family history of premature CHD in first-degree relatives improves risk prediction compared with the Framingham risk score (FRS) alone.

METHODS AND RESULTS

This study comprised 10,288 men and 12,553 women aged 40-79 years participating in the EPIC-Norfolk cohort who were followed for a mean of 10.9±2.1 years (mean±SD). The authors computed the FRS as well as a modified score taking into account family history of premature CHD. A family history of CHD was indeed associated with an increased risk of future CHD, independent of established risk factors (FRS-adjusted HR of 1.74 (95% CI 1.56 to 1.95) for family history of premature CHD). However, adding family history of CHD to the FRS resulted in a negative net reclassification of 2%. In the subgroup of individuals estimated to be at intermediate risk, family history of premature CHD resulted in an increase in net reclassification of 2%. The sensitivity increased with 0.4%, and the specificity decreased 0.8%.

CONCLUSION

Although family history of CHD was an independent risk factor of future CHD, its use did not improve classification of individuals into clinically relevant risk categories based on the FRS. Among study participants at intermediate risk of CHD, adding family history of premature CHD resulted in, at best, a modest improvement in reclassification of individuals into a more accurate risk category.

Increased prevalence of risk factors for cardiovascular disease in long-term survivors of acute lymphoblastic leukemia and Wilms tumor treated with radiotherapy

BACKGROUND

Only a few studies have assessed cardiovascular risk factors (CRFs) in childhood cancer survivors. We determined the prevalence of CRFs in long-term survivors of acute lymphoblastic leukemia (ALL) and Wilms tumor.

PROCEDURE

Adult survivors of ALL and Wilms tumor treated with radiotherapy and chemotherapy (RT + CT) or treated with chemotherapy alone (CT) were compared with sibling controls. CRFs (hypertension, diabetes mellitus, hypercholesterolemia, obesity, renal insufficiency) and hormonal deficiencies were assessed in each participant. Multivariate logistic regression analysis was used to evaluate the association between CRFs and treatment.

RESULTS

Seventy-nine ALL, 62 Wilms tumor survivors, and 69 control subjects (mean ages 24.5, 25.9, and 26 years, respectively) were enrolled. Mean follow-up time since cancer treatment was 20.8 years. In the Wilms RT + CT group significantly more survivors had hypertension (21.6% vs. 1.4%, P < 0.001) and renal insufficiency (8.1% vs. 0%, P = 0.016) compared to controls. There were also more patients with multiple CRFs in the Wilms RT + CT group (16.2% vs. 2.9% in controls, P = 0.019). Almost 15% of ALL RT + CT survivors had growth hormone deficiency. Hypogonadism was seen in 18.9% of survivors in the Wilms RT + CT group. We observed no significant differences between CT-treated survivors of both malignancies and controls. The adjusted odds ratio for the occurrence of at least one CRF was 2.6 increased for survivors following abdominal radiotherapy. Treatment with CT alone was not associated with the occurrence of multiple CRFs.

CONCLUSIONS

Long-term survivors of ALL and Wilms tumor have unfavorable CRFs due to previous RT not CT.

Functionality of sequence variants in the genes coding for the low-density lipoprotein receptor and apolipoprotein B in individuals with inherited hypercholesterolemia

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 4P75 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.108C4A, exon 2) and two in APOB (c.13154T4C and c.13181T4C, 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.

Assessment of atherosclerosis: the role of flow-mediated dilatation

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.

Ultrasound protocols to measure carotid intima-media thickness in trials; comparison of reproducibility, rate of progression, and effect of intervention in subjects with familial hypercholesterolemia and subjects with mixed dyslipidemia

BACKGROUND

Current ultrasound protocols to measure carotid intima-media thickness (CIMT) in trials rather differ. The ideal protocol combines high reproducibility with a high precision in the measurement of the rate of change in CIMT over time and with a precise estimate of a treatment effect. To study these aspects, a post-hoc analysis was performed using data from two randomized double-blind, placebo-controlled trials: one among 872 subjects with familial hypercholesterolemia (FH) and the other among 752 subjects with mixed dyslipidemia (MD), respectively. Participants were randomized to torcetrapib or placebo on top of optimal atorvastatin therapy.

METHODS

CIMT information was collected from the left and right carotid artery from two walls (the near and far wall) of three segments (common carotid, bifurcation, and internal carotid artery) at four different angles (right: 90, 120, 150, and 180 degrees on Meijer's carotid arc; left: 270, 240, 210, and 180 degrees, respectively). Based on combinations of these measurements, 60 different protocols were constructed to estimate a CIMT measure per participant (20 protocols for mean common CIMT, 40 protocols for mean maximum CIMT). For each protocol we assessed reproducibility (intra-class correlation coefficient (ICC), mean difference of duplicate base-line scans); 2-year progression rate in the atorvastatin group with its standard error (SE); and treatment effect (difference in rate of change in CIMT between torcetrapib and placebo) with its SE.

RESULTS

Reproducibility: ICC ranged from 0.77 to 0.91 among FH patients and from 0.68 to 0.86 among MD patients. CIMT progression rates ranged from -0.0030 to 0.0020 mm/year in the FH trial and from 0.00084 to 0.01057 mm/year in the MD trial, with SE ranging from 0.00054 to 0.00162 and from 0.00083 to 0.00229, respectively. The difference in CIMT progression rate between treatment arms ranged from -0.00133 to 0.00400 mm/year in the FH trial and from -0.00231 to 0.00486 mm/year in the MD trial. The protocol with the highest reproducibility, highest CIMT progression/precision ratio, and the highest treatment effect/precision ratio were those measuring mean common CIMT with measurements of the near and far wall at multiple angles. When the interest is in the mean maximum CIMT, protocols using multiple segments and angles performed the best.

CONCLUSION

Our findings support the position that the number and specific combination of segments, angles, and walls interrogated are associated with differences in reproducibility, magnitude, and precision of progression of CIMT over time, and treatment effect. The best protocols were mean common CIMT protocols in which both the near and far walls are measured at multiple angles.

Rosuvastatin for primary prevention among individuals with elevated high-sensitivity c-reactive protein and 5% to 10% and 10% to 20% 10-year risk. Implications of the Justification for Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial for "intermediate risk"

BACKGROUND

Recent primary prevention guidelines issued in Canada endorse the use of statin therapy among individuals at "intermediate risk" who have elevated levels of high-sensitivity C-reactive protein (hsCRP). However, trial data directly addressing whether this recommendation defines a patient population in which statin therapy is effective have not previously been published.

METHODS AND RESULTS

In the Justification for Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) trial, which demonstrated a 44% reduction in first vascular events when rosuvastatin 20 mg was compared with placebo among 17 802 primary prevention patients with LDL cholesterol <130 mg/dL and hsCRP ≥2 mg/L, 6091 participants (2525 women, 3566 men) had baseline estimated 10-year Framingham risks of 5% to 10% and 7340 participants (1404 women, 5936 men) had baseline estimated Framingham risk of 11% to 20%. In these 2 "intermediate risk" subgroups, relative risk reductions consistent with the overall trial treatment effect were observed (hazard ratio, 0.55; 95% confidence interval, 0.36 to 0.84; 5-year number needed to treat=40, P=0.005 for those with 5% to 10% risk; hazard ratio, 0.51; 95% confidence interval, 0.39 to 0.68, 5-year number needed to treat=18, P<0.0001 for those with 11% to 20% risk). Use of the Reynolds Risk Score to stratify the study population gave similar results but reclassified large numbers of individuals into lower- or higher-risk groups. The majority of women with elevated hsCRP who benefited from rosuvastatin were at 5% to 10% 10-year risk at study entry using either global risk scoring system.

CONCLUSIONS

Consistent with recent evidence-based Canadian Cardiovascular Society guidelines for primary prevention, the JUPITER trial demonstrates that rosuvastatin 20 mg significantly reduces major cardiovascular events among men and women with elevated hsCRP and "intermediate risk" defined either as 5% to 10% or 10% to 20% 10-year risk.

Apolipoprotein B synthesis inhibition: results from clinical trials

PURPOSE OF REVIEW

Mipomersen is a second-generation antisense oligonucleotide developed to inhibit the synthesis of apolipoprotein B-100 in the liver. In this review we will summarize the results of recent preclinical and clinical studies addressing safety and low-density lipoprotein-cholesterol (LDL-c) lowering efficacy of this new compound.

RECENT FINDINGS

In phase 3 clinical trials, mipomersen has been shown to significantly reduce LDL-c in patients with homozygous and heterozygous familial hypercholesterolemia on maximally tolerated lipid-lowering therapy. Injection site reactions, flu-like symptoms and increases in liver transaminases were the main adverse events. A recent safety study, designed to investigate the effects of mipomersen on intrahepatic triglyceride content, failed to show evidence of clinically relevant hepatic steatosis after 13 weeks of treatment.

SUMMARY

Mipomersen is a new agent to lower LDL-c in patients at increased risk of cardiovascular disease and/or intolerant to statins. Whereas safety concerns have focused on hepatic fat accumulation, to date no evidence of clinically relevant increases of intrahepatic triglyceride content are reported. Ongoing and future studies are eagerly awaited to assess the impact of mipomersen on hepatic triglyceride content after prolonged exposure.

HDL cholesterol and residual risk of first cardiovascular events after treatment with potent statin therapy: an analysis from the JUPITER trial

BACKGROUND

HDL-cholesterol concentrations are inversely associated with occurrence of cardiovascular events. We addressed, using the JUPITER trial cohort, whether this association remains when LDL-cholesterol concentrations are reduced to the very low ranges with high-dose statin treatment.

METHODS

Participants in the randomised placebo-controlled JUPITER trial were adults without diabetes or previous cardiovascular disease, and had baseline concentrations of LDL cholesterol of less than 3.37 mmol/L and high-sensitivity C-reactive protein of 2 mg/L or more. Participants were randomly allocated by a computer-generated sequence to receive rosuvastatin 20 mg per day or placebo, with participants and adjudicators masked to treatment assignment. In the present analysis, we divided the participants into quartiles of HDL-cholesterol or apolipoprotein A1 and sought evidence of association between these quartiles and the JUPITER primary endpoint of first non-fatal myocardial infarction or stroke, hospitalisation for unstable angina, arterial revascularisation, or cardiovascular death. This trial is registered with ClinicalTrials.gov, number NCT00239681.

FINDINGS

For 17,802 patients in the JUPITER trial, rosuvastatin 20 mg per day reduced the incidence of the primary endpoint by 44% (p<0.0001). In 8901 (50%) patients given placebo (who had a median on-treatment LDL-cholesterol concentration of 2.80 mmol/L [IQR 2.43-3.24]), HDL-cholesterol concentrations were inversely related to vascular risk both at baseline (top quartile vs bottom quartile hazard ratio [HR] 0.54, 95% CI 0.35-0.83, p=0.0039) and on-treatment (0.55, 0.35-0.87, p=0.0047). By contrast, among the 8900 (50%) patients given rosuvastatin 20 mg (who had a median on-treatment LDL-cholesterol concentration of 1.42 mmol/L [IQR 1.14-1.86]), no significant relationships were noted between quartiles of HDL-cholesterol concentration and vascular risk either at baseline (1.12, 0.62-2.03, p=0.82) or on-treatment (1.03, 0.57-1.87, p=0.97). Our analyses for apolipoprotein A1 showed an equivalent strong relation to frequency of primary outcomes in the placebo group but little association in the rosuvastatin group.

INTERPRETATION

Although measurement of HDL-cholesterol concentration is useful as part of initial cardiovascular risk assessment, HDL-cholesterol concentrations are not predictive of residual vascular risk among patients treated with potent statin therapy who attain very low concentrations of LDL cholesterol.

FUNDING

AstraZeneca.

Ezetimibe stimulates faecal neutral sterol excretion depending on abcg8 function in mice

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.

Long-term LDL-c lowering in heterozygous familial hypercholesterolemia normalizes carotid intima-media thickness

OBJECTIVE

We investigated the effectiveness of statins in daily practice in reducing the arterial wall thicknesses by comparing the carotid intima-media thickness (cIMT) between statin-treated familial hypercholesterolemia (FH) patients and their unaffected spouses.

METHODS

FH subjects treated with LDL-c lowering medication for at least 5 years and their unaffected spouses were included in this observational study. Clinical data and carotid intima-media thickness (cIMT) as surrogate marker for atherosclerosis were acquired.

RESULTS

In total 40 FH patients, age 48.4±4.2 years, and their 40 unaffected spouses, age 47.4±3.9 years, were included. Pre-treatment total cholesterol levels of FH patients were on average 9.3±2.0 mmol/L. Treated FH patients and unaffected spouses exhibited similar LDL-c (3.8±1.5 vs. 3.5±1.1 mmol/L; p=0.25) and total cholesterol levels (5.8±1.6 vs. 5.6±1.1 mmol/L; p=0.56). Also, in a multivariate model cIMT adjusted for age and sex did not differ between affected and spouses (95% CI: -0.032 to 0.092 mm; p=0.34).

CONCLUSION

Long-term statin treatment normalizes cIMT in severe FH patients and therefore it is likely that the extreme risk of cardiovascular disease in FH patients is significantly reduced by this therapy.

The hypertriglyceridemic-waist phenotype and the risk of coronary artery disease: results from the EPIC-Norfolk prospective population study

BACKGROUND

Screening for increased waist circumference and hypertriglyceridemia (the hypertriglyceridemic-waist phenotype) has been proposed as an inexpensive approach to identify patients with excess intra-abdominal adiposity and associated metabolic abnormalities. We examined the relationship between the hypertriglyceridemic-waist phenotype to the risk of coronary artery disease in apparently healthy individuals.

METHODS

A total of 21,787 participants aged 45-79 years were followed for a mean of 9.8 (standard deviation 1.7) years. Coronary artery disease developed in 2109 of them during follow-up. The hypertriglyceridemic-waist phenotype was defined as a waist circumference of 90 cm or more and a triglyceride level of 2.0 mmol/L or more in men, and a waist circumference of 85 cm or more and a triglyceride level of 1.5 mmol/L or more in women.

RESULTS

Compared with participants who had a waist circumference and triglyceride level below the threshold, those with the hypertriglyceridemic-waist phenotype had higher blood pressure indices, higher levels of apolipoprotein B and C-reactive protein, lower levels of high-density lipoprotein cholesterol and apolipoprotein A-I, and smaller low-density lipoprotein particles. Among men, those with the hypertriglyceridemic-waist phenotype had an unadjusted hazard ratio for future coronary artery disease of 2.40 (95% confidence interval [CI] 2.02-2.87) compared with men who did not have the phenotype. Women with the phenotype had an unadjusted hazard ratio of 3.84 (95% CI 3.20-4.62) compared with women who did not have the phenotype.

INTERPRETATION

Among participants from a European cohort representative of a contemporary Western population, the hypertriglyceridemic-waist phenotype was associated with a deteriorated cardiometabolic risk profile and an increased risk for coronary artery disease.

ABCG5/G8 polymorphisms and markers of cholesterol metabolism: systematic review and meta-analysis

Genetic variation at the ABCG5/G8 locus has been associated with markers of cholesterol homeostasis. As data originate from small-scale studies, we performed a meta-analysis to study these associations in a large dataset. We first investigated associations between five common ABCG5/G8 polymorphisms (p.Q604E, p.D19H, p.Y54C, p.T400K, and p.A632V) and plasma sterol levels in 245 hypercholesterolaemic individuals. No significant associations were found. Subsequently, our data were pooled into a meta-analysis that comprised 3,364 subjects from 16 studies (weighted mean age, 46.7 ± 10.5 years; BMI, 23.9 ± 3.5 kg/m(2)). Presence of the minor 632V allele correlated with reduced LDL-C concentrations (n = 367) compared with homozygosity for the 632A variant [n = 614; -0.11 mmol/l (95% CI, range: -0.20 to -0.02 mmol/l); P = 0.01]. The remaining polymorphisms were not associated with plasma lipid levels. Carriers of the 19H allele exhibited lower campesterol/TC (n = 83; P < 0.001), sitosterol/TC (P < 0.00001), and cholestanol/TC (P < 0.00001), and increased lathosterol/TC ratios (P = 0.001) compared with homozygous 19D allele carriers (n = 591). The ABCG8 632V variant was associated with a clinically irrelevant LDL-C reduction, whereas the 19H allele correlated with decreased cholesterol absorption and increased synthesis without affecting the lipid profile. Hence, associations between frequently studied missense ABCG5/G8 polymorphisms and markers of cholesterol homeostasis are modest at best.

Endothelial shear stress: a critical determinant of arterial remodeling and arterial stiffness in humans--a carotid 3.0-T MRI study

BACKGROUND

Low endothelial shear stress (ESS) elicits endothelial dysfunction. However, the relationship between ESS and arterial remodeling and arterial stiffness is unknown in humans. We developed a 3.0-T MRI protocol to evaluate the contribution of ESS to arterial remodeling and stiffness.

METHODS AND RESULTS

Fifteen young (aged 26 ± 3 years) and 15 older (aged 57 ± 3 years) healthy volunteers as well as 15 patients with cardiovascular disease (aged 63 ± 10 years) were enrolled. Phase-contrast MRI of the common carotid arteries was used to derive ESS data from the spatial velocity gradients close to the arterial wall. ESS measurements were performed on 3 occasions and showed excellent reproducibility (intraclass correlation coefficient, 0.79). Multiple linear regression analysis accounting for age and blood pressure revealed that ESS was an independent predictor of the following response variables: carotid wall thickness (regression coefficient [b], -0.19 mm(2) per N/m(2); P=0.02), lumen area (b, -15.5 mm(2) per N/m(2); P<0.001), and vessel size (b, -24.0 mm(2) per N/m(2); P<0.001). Segments of the artery wall exposed to lower ESS were significantly thicker than segments exposed to higher ESS within the same artery (P=0.009). Furthermore, ESS was associated with arterial compliance, accounting for age, blood pressure, and wall thickness (b, -0.003 mm(2)/mm Hg per N/m(2); P=0.04).

CONCLUSIONS

Our carotid MRI data show that ESS is an important determinant of arterial remodeling and arterial stiffness in humans. The data warrant further studies to evaluate use of carotid ESS as a noninvasive tool to improve the understanding of individual cardiovascular disease risk and to assess novel drug therapies in cardiovascular disease prevention.

Efficacy and safety of mipomersen, an antisense inhibitor of apolipoprotein B, in hypercholesterolemic subjects receiving stable statin therapy

OBJECTIVES

The aim of this study was to evaluate the efficacy and safety of mipomersen in hypercholesterolemic subjects taking stable statin therapy.

BACKGROUND

Mipomersen is an apolipoprotein (apo) B synthesis inhibitor that has demonstrated significant reductions in apo B and low-density lipoprotein (LDL) cholesterol in Phase 1 clinical trials in healthy volunteers.

METHODS

A randomized, placebo-controlled, dose-escalation Phase 2 study was designed to evaluate the effects of mipomersen in hypercholesterolemic subjects taking stable statin therapy. Seventy-four subjects were enrolled sequentially into 1 of 6 dose cohorts at a 4:1 (active/placebo) ratio. Subjects received 7 doses of 30 to 400 mg over 5 weeks in the first 5 cohorts and 15 doses of 200 mg over 13 weeks in the sixth cohort. Pre-specified end points included percentage change from baseline in apo B and LDL cholesterol. Safety was assessed with laboratory test results and by the incidence and severity of adverse events.

RESULTS

The apo B and LDL cholesterol were reduced by 19% to 54% and 21% to 52%, respectively, at doses of 100 mg/week mipomersen and higher in the 5-week treatment cohorts. Efficacy seemed to increase upon treatment for 13 weeks at a dose of 200 mg/week. Injection site reactions (mild to moderate erythema [90%]) and hepatic transaminase increases (17%) were the most common adverse events, leading to discontinuation in 2 subjects and 1 subject, respectively. In the 13-week treatment cohort, 5 of 10 subjects (50%) had elevations >or=3x the upper limit of normal, 4 of which persisted on 2 consecutive occasions.

CONCLUSIONS

Mipomersen might hold promise for treatment of patients not reaching target LDL cholesterol levels on stable statin therapy. Further studies are needed to address the mechanisms and clinical relevance of transaminase changes after mipomersen administration. (Dose-Escalating Safety Study in Subjects on Stable Statin Therapy; NCT00231569).

Cardiovascular outcomes and their relationships to lipoprotein components in patients with and without chronic kidney disease: results from the IDEAL trial

OBJECTIVES

In Incremental Decrease in Endpoints through Aggressive Lipid-lowering (IDEAL), we compared cardiovascular outcomes in patients with and without chronic kidney disease (CKD) (estimated glomerular filtration rate <60 mL min(-1) 1.73 m(-2)) and analysed relationships between lipoprotein components (LC) and major coronary events (MCE) and other cardiovascular (CV) events.

DESIGN

Exploratory analysis of CV endpoints in a randomized trial comparing high dose of atorvastatin to usual dose of simvastatin on MCE.

SETTINGS

Patients with CKD were compared with the non-CKD patients. Cox regression models were used to study the relationships between on-treatment levels of LC and incident MCE.

FINDINGS

Chronic kidney disease was strongly associated with cardiovascular end-points including total mortality. In patients with CKD, a significant benefit of high dose atorvastatin treatment was found for any CV events, stroke and peripheral artery disease, but not for MCE. However, all cardiovascular end-points except stroke and CV mortality were reduced in the non-CKD group. Differential changes in LC or relationships to LC could not explain the different treatment outcomes in MCE in the two groups.

INTERPRETATION

Chronic kidney disease was a powerful risk factor for all cardiovascular end-points. The reason why the significant reductions achieved by high-dose statin treatment in most CV end-points in the non-CKD group were only in part matched by similar reductions in the CKD patients is not apparent. This difference did not result from differential changes in or relations to LC, but limited power may have increased the possibility of chance findings.

Effect of apolipoprotein-B synthesis inhibition on liver triglyceride content in patients with familial hypercholesterolemia

To investigate the impact of mipomersen, an apolipoprotein B-100 (apoB) synthesis inhibitor, on intra-hepatic triglyceride content (IHTG content), we conducted a randomized, double-blind, placebo-controlled study in 21 patients with familial hypercholesterolemia (FH). Subjects received a weekly subcutaneous dose of 200 mg mipomersen or placebo for 13 weeks while continuing conventional lipid lowering therapy. The primary endpoint was change in IHTG content from week 0 to week 15 as measured by localized proton magnetic resonance spectroscopy (1H-MRS). Thirteen weeks of mipomersen administration reduced LDL-cholesterol by 22.0 (17.8) % and apoB by 19.9 (17.4) % (both P < 0.01). One of 10 patients (10%) in the mipomersen-treated group developed mild hepatic steatosis at week 15, which was reversible following mipomersen discontinuation. For the group, there was a trend toward an increase in IHTG content [placebo; baseline: 1.2% and week 15: 1.1%; change -0.1 (0.9). Mipomersen; baseline: 1.2% and week 15: 2.1%; change 0.8 (1.7) (P = 0.0513)]. Mipomersen administration for 13 weeks to subjects with FH is associated with a trend toward an increase in IHTG content. Future studies evaluating the effects of long-term use of mipomersen reaching more profound reductions in apoB are required prior to broader use of this compound.

Chemokine ligand 2 genetic variants, serum monocyte chemoattractant protein-1 levels, and the risk of coronary artery disease

OBJECTIVE

In humans, evidence about the association between levels of monocyte chemoattractant protein-1 (MCP-1), its coding gene chemokine (C-C motif) ligand 2 (CCL2), and risk of coronary artery disease (CAD) is contradictory.

METHODS AND RESULTS

We performed a nested case-control study in the prospective EPIC-Norfolk cohort investigating the relationship between CCL2 single-nucleotide polymorphisms (SNPs), MCP-1 concentrations, and the risk of future CAD. Cases (n=1138) were apparently healthy men and women aged 45 to 79 years who developed fatal or nonfatal CAD during a mean follow-up of 6 years. Controls (n=2237) were matched by age, sex, and enrollment time. Using linear regression analysis no association between CCL2 SNPs and MCP-1 serum concentrations became apparent, nor did we find a significant association between MCP-1 serum levels and risk of future CAD. Finally, Cox regression analysis showed no significant association between CCL2 SNPs and the future CAD risk. In addition, we did not find any robust associations between the CCL2 haplotypes and MCP-1 serum concentration or future CAD risk.

CONCLUSIONS

Our data do not support previous publications indicating that MCP-1 is involved in the pathogenesis of CAD.

The HDL hypothesis: does high-density lipoprotein protect from atherosclerosis?

There is unequivocal evidence of an inverse association between plasma high-density lipoprotein (HDL) cholesterol concentrations and the risk of cardiovascular disease, a finding that has led to the hypothesis that HDL protects from atherosclerosis. This review details the experimental evidence for this "HDL hypothesis". In vitro studies suggest that HDL has a wide range of anti-atherogenic properties but validation of these functions in humans is absent to date. A significant number of animal studies and clinical trials support an atheroprotective role for HDL; however, most of these findings were obtained in the context of marked changes in other plasma lipids. Finally, genetic studies in humans have not provided convincing evidence that HDL genes modulate cardiovascular risk. Thus, despite a wealth of information on this intriguing lipoprotein, future research remains essential to prove the HDL hypothesis correct.

Carriers of loss-of-function mutations in ABCA1 display pancreatic beta-cell dysfunction

OBJECTIVE

Abnormal cellular cholesterol handling in islets may contribute to beta-cell dysfunction in type 2 diabetes. beta-Cell deficiency for the ATP binding cassette transporter A1 (ABCA1), which mediates the efflux of cellular cholesterol, leads to altered intracellular cholesterol homeostasis and impaired insulin secretion in mice. We aimed to assess the impact of ABCA1 dysfunction on glucose homeostasis in humans.

RESEARCH DESIGN AND METHODS

In heterozygous carriers of disruptive mutations in ABCA1 and family-based noncarriers of similar age, sex, and BMI, we performed oral glucose tolerance tests (OGTTs) (n = 15 vs. 14) and hyperglycemic clamps (n = 8 vs. 8).

RESULTS

HDL cholesterol levels in carriers were less than half those in noncarriers, but LDL cholesterol levels did not differ. Although fasting plasma glucose was similar between groups, glucose curves after an OGTT were mildly higher in carriers than in noncarriers. During hyperglycemic clamps, carriers demonstrated lower first-phase insulin secretion than noncarriers but no difference in insulin sensitivity. The disposition index (a measure of beta-cell function adjusted for insulin sensitivity) of the carriers was significantly reduced in ABCA1 heterozygotes.

CONCLUSIONS

Carriers of loss-of-function mutations in ABCA1 show impaired insulin secretion without insulin resistance. Our data provide evidence that ABCA1 is important for normal beta-cell function in humans.

Comparison between gradient gel electrophoresis and nuclear magnetic resonance spectroscopy in estimating coronary heart disease risk associated with LDL and HDL particle size

BACKGROUND

Gradient gel electrophoresis (GGE) and nuclear magnetic resonance (NMR) spectroscopy are both widely accepted methods for measuring LDL and HDL particle size. However, whether or not GGE- or NMR-measured LDL or HDL particle size predicts coronary heart disease (CHD) risk to a similar extent is currently unknown.

METHODS

We used GGE and NMR to measure LDL and HDL particle size in a nested case-control study of 1025 incident cases of CHD and 1915 controls from the EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk study. The study sample included apparently healthy men and women age 45-79 years followed for an average of 6 years.

RESULTS

Pearson correlation coefficients showed that the overall agreement between NMR and GGE was better for the measurement of HDL size (r = 0.78) than for LDL size (r = 0.47). The odds ratio for future CHD among participants in the bottom tertile of LDL size (smallest LDL particles) was 1.35 (95% CI, 1.12-1.63) for GGE and 1.74 (1.41-2.15) for NMR. For HDL size, these respective odds ratios were 1.41 (1.16-1.72) and 1.85 (1.47-2.32). After adjustment for potential confounders, the relationship between small LDL or HDL particles and CHD was no longer significant, irrespective of the method.

CONCLUSIONS

In this prospective population study, we found that the relationships between NMR-measured LDL and HDL sizes and CHD risk were slightly higher than those obtained with GGE.

Completeness of carotid intima media thickness measurements depends on body composition: the RADIANCE 1 and 2 trials

AIM

Ultrasound protocols to measure carotid intima media thickness (CIMT) differ considerably with regard to the inclusion of the number of carotid segments and angles used. Detailed information on the completeness of CIMT information is often lacking in published reports, and at most, overall percentages are presented. We therefore decided to study the completeness of CIMT measurements and its relation with vascular risk factors using data from two CIMT intervention studies: one among familial hypercholesterolemia (FH) patients, the Rating Atherosclerotic Disease change by Imaging With A New CETP Inhibitor (RADIANCE 1), and one among mixed dyslipidemia (MD) patients, the Rating Atherosclerotic Disease change by Imaging With A New CETP Inhibitor (RADIANCE 2).

METHODS

We used baseline ultrasound scans from the RADIANCE 1 (n=872) and RADIANCE 2 (n=752) studies. CIMT images were recorded for 12 artery-wall combinations (near and far walls of the left and right common carotid artery (CCA), bifurcation (BIF) and internal carotid artery (ICA) segments) at 4 set angles, resulting in 48 possible measurements per patient. The presence or absence of CIMT measurements was assessed per artery-wall combination and per angle. The relation between completeness and patient characteristics was evaluated with logistic regression analysis.

RESULTS

In 89% of the FH patients, information on CIMT could be obtained on all twelve carotid segments, and in 7.6%, eleven segments had CIMT information (nearly complete 96.6%). For MD patients this was 74.6% and 17.9%, respectively (nearly complete: 92.5%). Increased body mass index and increased waist circumference were significantly (p=0.01) related to less complete data in FH patients. For MD patients, relations were seen with increased waist circumference (p<0.01). Segment-specific data indicated that in FH patients, completeness was less for the near wall of the left (96%) and right internal carotid artery (94%) as compared to other segments (all >98%). In MD patients, completeness was lower for the near wall of both the right and left carotid arteries: 86.0% and 90.8%, respectively, as compared to other segments (all >97%).

CONCLUSIONS

With the current ultrasound protocols it is possible to obtain a very high level of completeness. Apart from the population studied, body mass index and waist circumference are important in achieving complete CIMT measurements.

Dalcetrapib: no off-target toxicity on blood pressure or on genes related to the renin-angiotensin-aldosterone system in rats

BACKGROUND AND PURPOSE

The association between torcetrapib and its off-target effects on blood pressure suggested a possible class-specific effect. The effects of dalcetrapib (RO4607381/JTT-705) and torcetrapib on haemodynamics and the renin-angiotensin-aldosterone system (RAAS) were therefore assessed in a rat model.

EXPERIMENTAL APPROACH

Arterial pressure (AP) and heart rate were measured by telemetry in normotensive and spontaneously hypertensive rats (SHR) receiving torcetrapib 10, 40 or 80 mg kg(-1) day(-1); dalcetrapib 100, 300 or 500 mg(-1) kg day(-1); or vehicle (placebo) for 5 days. Expression of RAAS genes in adrenal gland, kidney, aorta and lung from normotensive rats following 5 days' treatment with torcetrapib 40 mg kg(-1) day(-1), dalcetrapib 500 mg kg(-1) day(-1) or vehicle was measured by quantitative polymerase chain reaction.

KEY RESULTS

Torcetrapib transiently increased mean AP in normotensive rats (+3.7 +/- 0.1 mmHg), whereas treatment in SHR resulted in a dose-dependent and sustained increase [+6.5 +/- 0.6 mmHg with 40 mg kg(-1) day(-1) at day 1 (P < 0.05 versus placebo)], which lasted over the treatment period. No changes in AP or heart rate were observed with dalcetrapib. Torcetrapib, but not dalcetrapib, increased RAAS-related mRNAs in adrenal glands and aortas.

CONCLUSIONS AND IMPLICATIONS

In contrast to torcetrapib, dalcetrapib did not increase blood pressure or RAAS-related gene expression in rats, suggesting that the off-target effects of torcetrapib are not a common feature of all compounds acting on cholesteryl ester transfer protein.

Two years after molecular diagnosis of familial hypercholesterolemia: majority on cholesterol-lowering treatment but a minority reaches treatment goal

Background

The risk of premature cardiovascular disease in patients with familial hypercholesterolemia (FH) can be profoundly reduced by cholesterol-lowering therapy, and current guidelines for FH advocate ambitious low-density lipoprotein cholesterol (LDL-C) goals. In the present study, we determined whether these goals are reflected in current clinical practice once FH has been diagnosed.

Methodology/Principal Findings

In 2008, we sent questionnaires to all subjects (aged 18–65 years) who were molecularly diagnosed with FH in the year 2006 through the screening program in the Netherlands. Of these 1062 subjects, 781 completed the questionnaire (46% males; mean age: 42±12 years; mean LDL-C at molecular diagnosis (baseline): 4.1±1.3 mmol/L). The number of persons that used cholesterol-lowering therapy increased from 397 (51%) at baseline to 636 (81%) after diagnosis. Mean treated LDL-C levels decreased significantly to 3.2±1.1 mmol/L two years after diagnosis. Only 22% achieved the LDL-C target level of ≤2.5 mmol/L.

Conclusions/Significance

The proportion of patients using cholesterol-lowering medication was significantly increased after FH diagnosis through genetic cascade screening. The attained LDL-C levels were lower than those reported in previous surveys on medication use in FH, which could reflect the effect of more stringent lipid target levels. However, only a minority of the medication users reached the LDL-C target.

Targeting cardiovascular risk in rheumatoid arthritis: a dual role for statins

Rheumatoid arthritis (RA) is a prototypical immune-mediated inflammatory disease that is characterized by increased cardiovascular morbidity and mortality, independent of the traditional risk factors for cardiovascular disease. The chronic inflammatory state--a hallmark of RA--is considered to be a driving force for accelerated atherogenesis. Consequently, aggressive control of RA disease activity is thought to be instrumental for cardiovascular risk reduction. Currently, statin-mediated reduction of LDL-cholesterol levels is considered to be the cornerstone of cardiovascular disease prevention. In addition to their lipid-lowering capabilities, statins exert immunomodulatory effects, which could be of dual benefit in the treatment of RA. Guidelines on the reduction of cardiovascular risk in patients with RA are lacking, however, largely owing to the absence of data from randomized controlled trials. This Review focuses on the pathophysiology of cardiovascular events in RA, as well as the need to adjust cardiovascular risk engines to better-accommodate the impact of chronic inflammatory disease over and above the established risk factors to predict cardiovascular risk in patients with RA.

Chylomicronemia with low postheparin lipoprotein lipase levels in the setting of GPIHBP1 defects

BACKGROUND

Recent studies in mice have established that an endothelial cell protein, glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), is essential for the lipolytic processing of triglyceride-rich lipoproteins.

METHODS AND RESULTS

We report the discovery of a homozygous missense mutation in GPIHBP1 in a young boy with severe chylomicronemia. The mutation, p.C65Y, replaces a conserved cysteine in the GPIHBP1 lymphocyte antigen 6 domain with a tyrosine and is predicted to perturb protein structure by interfering with the formation of a disulfide bond. Studies with transfected Chinese hamster ovary cells showed that GPIHBP1-C65Y reaches the cell surface but has lost the ability to bind lipoprotein lipase (LPL). When the GPIHBP1-C65Y homozygote was given an intravenous bolus of heparin, only trace amounts of LPL entered the plasma. We also observed very low levels of LPL in the postheparin plasma of a subject with chylomicronemia who was homozygous for a different GPIHBP1 mutation (p.Q115P). When the GPIHBP1-Q115P homozygote was given a 6-hour infusion of heparin, a significant amount of LPL appeared in the plasma, resulting in a fall in the plasma triglyceride levels from 1780 to 120 mg/dL.

CONCLUSIONS

We identified a novel GPIHBP1 missense mutation (p.C65Y) associated with defective LPL binding in a young boy with severe chylomicronemia. We also show that homozygosity for the C65Y or Q115P mutations is associated with low levels of LPL in the postheparin plasma, demonstrating that GPIHBP1 is important for plasma triglyceride metabolism in humans.

The metabolism of triglyceride-rich lipoproteins revisited: new players, new insight

Peripheral lipoprotein lipase (LPL)-mediated lipolysis of triglycerides is the first step in chylomicron/VLDL clearance involving heparan sulfate proteoglycans (HSPGs) displayed at the cell surface of the capillaries in adipose tissue, heart and skeletal muscle. The newly generated chylomicron remnant particles are then cleared by the liver, whereas VLDL remnant particles are either further modified, through the action of hepatic lipase (HL) and cholesteryl ester transfer protein (CETP), into LDL particles or alternatively directly cleared by the liver. Two proteins, lipase maturation factor 1 (LMF1) and glycosylphosphatidylinositol-anchored high density lipoprotein binding protein 1 (GPIHBP1), have been recently identified and have revised our current understanding of LPL maturation and LPL-mediated lipolysis. Moreover, new insights have been gained with respect to hepatic remnant clearance using genetically modified mice targeting the sulfation of HSPGs and even deletion of the most abundant heparan sulfate proteoglycan: syndecan1. In this review, we will provide an overview of novel data on both peripheral TG hydrolysis and hepatic remnant clearance that will improve our knowledge of plasma triglyceride metabolism.

Separating the mechanism-based and off-target actions of cholesteryl ester transfer protein inhibitors with CETP gene polymorphisms

BACKGROUND

Cholesteryl ester transfer protein (CETP) inhibitors raise high-density lipoprotein (HDL) cholesterol, but torcetrapib, the first-in-class inhibitor tested in a large outcome trial, caused an unexpected blood pressure elevation and increased cardiovascular events. Whether the hypertensive effect resulted from CETP inhibition or an off-target action of torcetrapib has been debated. We hypothesized that common single-nucleotide polymorphisms in the CETP gene could help distinguish mechanism-based from off-target actions of CETP inhibitors to inform on the validity of CETP as a therapeutic target.

METHODS AND RESULTS

We compared the effect of CETP single-nucleotide polymorphisms and torcetrapib treatment on lipid fractions, blood pressure, and electrolytes in up to 67 687 individuals from genetic studies and 17 911 from randomized trials. CETP single-nucleotide polymorphisms and torcetrapib treatment reduced CETP activity and had a directionally concordant effect on 8 lipid and lipoprotein traits (total, low-density lipoprotein, and HDL cholesterol; HDL2; HDL3; apolipoproteins A-I and B; and triglycerides), with the genetic effect on HDL cholesterol (0.13 mmol/L, 95% confidence interval [CI] 0.11 to 0.14 mmol/L) being consistent with that expected of a 10-mg dose of torcetrapib (0.13 mmol/L, 95% CI 0.10 to 0.15). In trials, 60 mg of torcetrapib elevated systolic and diastolic blood pressure by 4.47 mm Hg (95% CI 4.10 to 4.84 mm Hg) and 2.08 mm Hg (95% CI 1.84 to 2.31 mm Hg), respectively. However, the effect of CETP single-nucleotide polymorphisms on systolic blood pressure (0.16 mm Hg, 95% CI -0.28 to 0.60 mm Hg) and diastolic blood pressure (-0.04 mm Hg, 95% CI -0.36 to 0.28 mm Hg) was null and significantly different from that expected of 10 mg of torcetrapib.

CONCLUSIONS

Discordance in the effects of CETP single-nucleotide polymorphisms and torcetrapib treatment on blood pressure despite the concordant effects on lipids indicates the hypertensive action of torcetrapib is unlikely to be due to CETP inhibition or shared by chemically dissimilar CETP inhibitors. Genetic studies could find a place in drug-development programs as a new source of randomized evidence for drug-target validation in humans.

Lipid measures and cardiovascular disease prediction

Traditional lipid measures are the cornerstone of risk assessment and treatment goals in cardiovascular prevention. Whereas the association between total, LDL-, HDL-cholesterol and cardiovascular disease risk has been generally acknowledged, the rather poor capacity to distinguish between patients who will and those who will not develop cardiovascular disease has prompted the search for further refinement of these traditional measures. A thorough understanding of lipid metabolism is mandatory to understand recent developments in this area. After a brief overview of lipid metabolism we will discuss the epidemiological data of total, LDL- and HDL-cholesterol and focus on recent advances in measurements of these lipoproteins. In addition we will discuss the role of triglycerides and the apolipoprotein B–A-I ratio on the incidence of cardiovascular disease.

Heterozygous familial hypercholesterolaemia in childhood: cardiovascular risk prevention

Children with familial hypercholesterolaemia (FH) have severely increased low-density lipoprotein cholesterol (LDL-C) levels that strongly predispose to premature cardiovascular disease (CVD) later in life. Early identification makes it possible to start lipid-lowering therapy at young age to prevent CVD. The atherosclerotic process can be inhibited by potent lipid-lowering therapy. The cornerstone of lipid-lowering therapy is a healthy lifestyle, but most of the time this is insufficient to reach adequate LDL-C goals. Subsequently, pharmacological therapy is initiated with increasing frequency. In the past decade numerous studies have assessed the efficacy and safety of statins in children with FH. Those studies demonstrate that statins are well tolerated, safe and effective. Therefore, these agents have a pivotal role in the treatment of children with FH.

Pregnancy in women suffering from familial hypercholesterolemia: a harmful period for both mother and newborn?

PURPOSE OF REVIEW

The present review aims to highlight the consequences for mother and child of profound hypercholesterolemia during pregnancy of women with familial hypercholesterolemia.

RECENT FINDINGS

Familial hypercholesterolemia is increasingly diagnosed in younger patients due to the existence of screening programs and more widespread cholesterol testing. Increasing numbers of young female patients with familial hypercholesterolemia raise the issue of pregnancy and its consequences for the familial hypercholesterolemia patient herself but also for her offspring. When pregnancy is considered, lipid-lowering drugs are often discontinued because of the fear for teratogenic effects. The evidence for teratogenesis associated with statin use is scant and conflicting. On the other hand, several studies do suggest that pronounced hypercholesterolemia during pregnancy has adverse effects on both fetus and mother. In fact, human and animal studies reveal an enhanced tendency toward atherosclerosis in the offspring of women who suffer from hypercholesterolemia during pregnancy. In animal studies, some evidence exists that this can be reversed by treatment with lipid-lowering and antioxidative agents. Until today, however, no human studies exist that have evaluated efficacy or safety of lipid-lowering interventions in pregnant women with familial hypercholesterolemia.

SUMMARY

Altogether, the suggested relationship between severe hypercholesterolemia and enhanced atherosclerosis in offspring and possibly the mother warrants further confirmation and, consequently, studies that focus on therapeutic strategies that can safely lower cholesterol levels during pregnancy in these women.