Influence of HDL cholesterol on preclinical carotid atherosclerosis in familial hypercholesterolemia

Effects of NAD+ precursors on blood pressure, C-reactive protein concentration and carotid intima-media thickness: A meta-analysis of randomized controlled trials

BACKGROUND

There are contradictory effects regarding the effect of NAD+ precursor on blood pressure and inflammation. In order to obtain a better viewpoint from them, this study aimed to comprehensively investigate the effects of NAD+ precursor supplementation on blood pressure, C-reactive protein (CRP) and carotid intima-media thickness (CIMT).

METHODS

PubMed/MEDLINE, Web of Science, SCOPUS and Embase databases were searched using standard keywords to identify all controlled trials investigating the effects of NAD+ precursor on blood pressure, CRP and CIMT. Pooled weighted mean difference (WMD) and 95% confidence intervals (95% CI) were achieved by random-effects model analysis for the best estimation of outcomes.

RESULTS

Twenty-nine articles (with 8664 participants) were included in this article. Results from meta-analyses of RCTs from random-effects models indicated a significant reduction in systolic (SBP) (weighted mean difference (WMD): -2.54 mmHg, p < .001) and diastolic blood pressure (DBP) (WMD: -2.15 mmHg, p < .001), as well as in CRP (WMD: -.93 mg/L, 95% CI -1.47 to -.40, p < .001) concentrations and CIMT (WMD: -.01 mm, 95% CI -.02 to -.00, p = .005) with the NAD+ precursors supplementation compared with the control group. In addition, a greater effect of supplementation with NAD+ precursors in reducing blood pressure (BP) were observed with the highest dose (≥2 g) and duration of the intervention (>12 weeks), as well as with NA supplementation when compared to NE.

CONCLUSIONS

Overall, these findings suggest that NAD+ precursor supplementation might have a beneficial effect on cardiovascular risk factors such as BP, CRP concentration and CIMT.

Synergistic Effects of Inflammation and Atherogenic Dyslipidemia on Subclinical Carotid Atherosclerosis Assessed by Ultrasound in Patients with Familial Hypercholesterolemia and Their Family Members

Low-density lipoprotein cholesterol (LDL-C) and total to high-density lipoprotein cholesterol (TC/HDL-C) ratio are both common risk factors for atherosclerotic cardiovascular diseases (ASCVDs). However, whether high-sensitivity C-reactive protein (hsCRP) has synergistic or attenuated effects on atherogenic dyslipidemia remains unclear. We investigated subclinical carotid atherosclerosis in patients with familial hypercholesterolemia (FH) and their family members. A total of 100 families with 761 participants were prospectively studied. Participants were categorized into four groups according to atherogenic dyslipidemia and inflammatory biomarkers. The group with LDL-C ≥ 160 mg/dL (or TC/HDL-C ratio ≥ 5) combined with hsCRP ≥ 2 mg/L have a thicker carotid intima-media thickness (CIMT) in different common carotid artery (CCA) areas and a higher percentage of high plaque scores compared with other subgroups. Multivariate logistic regression analysis revealed a significantly higher adjusted odds ratio (aOR) for thicker CIMT of 3.56 (95% CI: 1.56–8.16) was noted in those with concurrent LDL-C ≥ 160 mg/dL and hsCRP ≥ 2 mg/L compared with the group with concurrent LDL-C < 160 mg/dL and hsCRP < 2 mg/L. Our results demonstrated that systemic inflammation, in terms of higher hsCRP levels ≥ 2 mg/L, synergistically contributed to atherogenic dyslipidemia of higher LDL-C or a higher TC/HDL-C ratio on subclinical atherosclerosis.

Substantially Elevated Atherosclerotic Risks in Japanese Severe Familial Hypercholesterolemia Defined by the International Atherosclerosis Society

BACKGROUND

The International Atherosclerosis Society (IAS) has proposed "severe familial hypercholesterolemia" (FH) as a phenotype with the highest cardiovascular risk. However, whether this criteria could appropriately stratify a high-risk Japanese patient with FH remains unknown.

OBJECTIVES

This study sought to characterize atherosclerotic cardiovascular diseases in IAS-defined Japanese subjects with severe FH.

METHODS

This study analyzed 380 clinically diagnosed subjects with heterozygous FH without any history of atherosclerotic cardiovascular diseases. Severe FH was defined as untreated low-density lipoprotein cholesterol >400 mg/dL, >310 mg/dL plus 1 high-risk feature, or >190 mg/dL plus 2 high-risk features according to IAS-proposed statement. The occurrence of first and subsequent composite outcomes (cardiac [cardiac death + coronary artery disease + coronary revascularization] and noncardiac events [stroke + peripheral artery disease] was compared between subjects with severe (n = 135) and non-severe (n = 227) FH.

RESULTS

Severe FH was identified in 40.3% of study population. They had higher low-density lipoprotein cholesterol (P < 0.001) and lipoprotein(a) (P = 0.03) levels. Moreover, they more frequently received high-intensity statin (P < 0.001), PCSK9 inhibitor (P < 0.001), and lipoprotein apheresis (P = 0.01) than nonsevere FH subjects did, which resulted in a lower on-treatment low-density lipoprotein cholesterol level of subjects with severe FH (113 ± 47.2 vs 130 ± 53.9 mg/dL; P = 0.007). However, during the 7.4-year observational period, subjects with severe FH exhibited a 9.3-, 15.4-, and 5.9-fold greater risk for first composite (P < 0.001), cardiac (P < 0.001), and noncardiac outcomes (P = 0.02), respectively. Multivariate Cox proportional hazard model consistently revealed the 7.8- and 7.9-fold elevated risks of first (P < 0.001) and of subsequent (P < 0.001) composite outcomes in subjects with severe FH.

CONCLUSIONS

Japanese subjects with severe FH present profound risks of both first and subsequent atherosclerotic cardiovascular diseases in the primary prevention settings. These findings support the clinical applicability of IAS-defined severe FH in Japanese patients, which identifies those who require further stringent antiatherosclerotic management.

Familial Hypercholesterolemia: Do HDL Play a Role?

Cardiovascular disease (CVD) in heterozygous familial hypercholesterolemia (HeFH), the most frequent monogenic disorder of human metabolism, is largely driven by low-density lipoprotein (LDL) cholesterol concentrations. Since the CVD rate differs considerably in this population, beyond the lifetime LDL cholesterol vascular accumulation, other classical risk factors are involved in the high cardiovascular risk of HeFH. Among other lipoprotein disturbances, alterations in the phenotype and functionality of high-density lipoproteins (HDL) have been described in HeFH patients, contributing to the presence and severity of CVD. In fact, HDL are the first defensive barrier against the burden of high LDL cholesterol levels owing to their contribution to reverse cholesterol transport as well as their antioxidant and anti-inflammatory properties, among others. In this context, the present narrative review aimed to focus on quantitative and qualitative abnormalities in HDL particles in HeFH, encompassing metabolic, genetic and epigenetic aspects.

Factors Associated with Carotid Atherosclerosis and Achilles Tendon Thickness in Japanese Patients with Familial Hypercholesterolemia: A Subanalysis of the Familial Hypercholesterolemia Expert Forum (FAME) Study

AIMS

Familial hypercholesterolemia (FH) is characterized by high low-density lipoprotein (LDL) cholesterol levels, xanthomas including Achilles tendon thickening, and premature coronary artery disease (CAD). Carotid intima-media thickness (IMT) is a well-established surrogate marker for CAD in FH and Achilles tendon thickening is a specific physical finding in patients with FH. The objective of the present study was to identify factors associated with carotid IMT and Achilles tendon thickness in FH heterozygotes on lipid-lowering therapy. This study also aimed to examine the follow-up changes in carotid IMT and Achilles tendon thickness among them in the current real-world FH practice.

METHODS

The current study is a subanalysis of the Familial Hypercholesterolemia Expert Forum (FAME) Study. The severity of carotid atherosclerosis was assessed with the maximal and mean IMT using ultrasonography, and Achilles tendon thickness was measured using X-rays. The present study used 571 patients under medical treatment for heterozygous FH who had baseline measurements for maximal IMT (n=511), mean IMT (n=459), or Achilles tendon thickness (n=486). The IMT was measured annually, and Achilles tendon thickness was evaluated every two years.

RESULTS

Higher LDL cholesterol (LDL-C) level and lower HDL cholesterol (HDL-C) level were associated with greater maximal and mean IMT as well as greater Achilles tendon thickness. Achilles tendon thickness tended to be greater in patients who had a smoking history than in never-smokers. Maximal IMT and Achilles tendon thickness were significantly greater in patients with CAD than in those without. Additionally, lower HDL-C level and hypertension were associated with higher values of maximal and mean IMT, suggesting the importance of comprehensive risk management including reduced HDL-C and blood pressure control in FH care. In longitudinal observations, percentage changes in maximal IMT and mean IMT gradually increased during the observation period. In contrast, percentage changes in Achilles tendon thickness became progressively thinner throughout the observation period.

CONCLUSIONS

We found a positive association between LDL-C levels and severity of carotid atherosclerosis in heterozygous FH patients on treatment. This observation suggests the insufficiency of lipid-lowering therapy and the presence of therapeutic inertia among clinicians in the real-world FH practice.

Apolipoproteins A1 and B and their ratio in acute ischemic stroke patients with intracranial and extracranial arterial stenosis: an Egyptian study

Background

Apolipoprotein A1 and B and their ratio are considered a better biomarker for cardiovascular diseases than a lipid profile, but this previous finding is not proved to cerebrovascular ischemic diseases. The aim of this study is to assess the relation between apolipoprotien A1 and B and their ratio to intra- and extracranial carotid atherosclerosis in patients with ischemic acute stroke.

Methods

90 Egyptian patients with acute ischemic stroke are included in the study, and they have been classified into 3 groups: group 1 includes 30 patients with intracranial stenosis, group 2 includes 30 patients with extracranial arterial stenosis, and group 3 includes 30 patients with non-arterial stenosis. Patients were subjected to clinical assessment, routine laboratory measures, and Color-Coded Duplex Sonography for extracranial and intracranial arteries. The measurement of serum levels of apolipoproteins A1 and B was done using enzyme-linked immuno-sorbent assay (ELISA).

Results

A statistically significant difference was found between patient groups as regards the frequency of abnormal serum LDL-cholesterol (p = 0.04), being elevated in patients with extracranial stenosis (p = 0.01). There was a significant difference between patients groups as regards the frequency of abnormal serum HDL-cholesterol (p = 0.02), being lower in patients with extracranial stenosis. High Apo B/A1 ratio was an independent risk factor for intracranial arterial stenosis (p = 0.045). An abnormal elevation of serum LDL cholesterol was an independent risk factor of extracranial arterial stenosis (p = 0.021).

Conclusion

Apo B/A1 ratio is an independent risk factor for intracranial arterial stenosis, while serum LDL cholesterol is an independent risk factor for extracranial arterial stenosis. Apo B/A1 ratio and serum LDL cholesterol are reliable serum biomarkers for cranial arterial stenosis in acute ischemic stroke patients.

Red Blood Cell Eicosapentaenoic Acid Inversely Relates to MRI-Assessed Carotid Plaque Lipid Core Burden in Elders at High Cardiovascular Risk

Supplemental marine omega-3 eicosapentaenoic acid (EPA) has an anti-atherosclerotic effect. Clinical research on EPA supplied by the regular diet and atherosclerosis is scarce. In the framework of the PREvención con DIeta MEDiterránea (PREDIMED) trial, we conducted a cross-sectional study in 161 older individuals at high vascular risk grouped into different stages of carotid atherosclerosis severity, including those without ultrasound-detected atheroma plaque (n = 38), with plaques <2.0 mm thick (n = 65), and with plaques ≥2.0 mm (n = 79). The latter were asked to undergo contrast-enhanced 3T magnetic resonance imaging (MRI) and were subsequently grouped into absence (n = 31) or presence (n = 27) of MRI-detectable plaque lipid, a main feature of unstable atheroma plaques. We determined the red blood cell (RBC) proportion of EPA (a valid marker of long-term EPA intake) at enrolment by gas chromatography. In multivariate models, EPA related inversely to MRI-assessed plaque lipid volume, but not to maximum intima-media thickness of internal carotid artery, plaque burden, or MRI-assessed normalized wall index. The inverse association between EPA and plaque lipid content in patients with advanced atherosclerosis supports the notion that this fatty acid might improve cardiovascular health through stabilization of advanced atheroma plaques.

Nuclear magnetic resonance lipoprotein abnormalities in newly-diagnosed type 2 diabetes and their association with preclinical carotid atherosclerosis

BACKGROUND AND AIMS

Atherogenic dyslipidemia is common in type 2 diabetes (T2DM) and predicts cardiovascular disease, but information on the association of its components with atherosclerosis is scarce. We aimed to assess differences in the lipoprotein profile in newly-diagnosed T2DM and matched control individuals and their associations with preclinical carotid atherosclerosis.

METHODS

In a case-control study, we evaluated lipoprotein profiles by nuclear magnetic resonance (NMR) spectroscopy and determined carotid intima-media thickness (IMT) and plaque presence (IMT ≥1.5 mm) by B-mode ultrasonography.

RESULTS

We assessed 96 T2DM patients (median age 63 years, 44% women, 19% smokers, 54% hypertension, 38% dyslipidemia) and 90 non-diabetic controls matched for age, sex, and cardiovascular risk factors. In T2DM VLDL-particles (mainly large and enriched in cholesterol and triglycerides) were increased, and large HDL-particles (enriched in triglycerides and depleted in cholesterol) were reduced (p < 0.05; all comparisons). Regarding associations with preclinical atherosclerosis, VLDL triglyceride content (odds ratio [OR], 8.975; 95% confidence interval [CI], 2.330-34.576), total number of VLDL particles (OR, 2.713; CI, 1.601-4.598) and VLDL size (OR, 2.044; CI, 1.320-3.166), and the ratio cholesterol/triglycerides in HDL (OR, 0.638; CI, 0.477-0.852) were associated with plaque burden (≥3 plaques) independently of confounders, including conventional lipid levels.

CONCLUSION

NMR-assessed advanced lipoprotein profile identifies lipid abnormalities associated with newly-diagnosed T2DM and preclinical atherosclerosis that are not captured by the traditional lipid profile. At this early stage of diabetes, NMR lipoproteins could be useful to identify candidates for a more comprehensive cardiovascular risk prevention strategy.

Effect of weight loss on abnormal 24-hour blood pressure patterns in severely obese patients

BACKGROUND

Nocturnal hypertension (night systolic [S]/diastolic [D] blood pressure [BP]≥120/70 mm Hg), nondipper status (nocturnal BP fall<10% of daytime values), and pulse pressure ([PP]; difference between 24-h SBP and DBP readings) are associated with increased risk of cardiovascular disease. We evaluated the 1-year effect of significant surgical weight loss (WL) on abnormal BP patterns in patients with and without hypertension and identified the factors involved.

SETTING

University hospital, Spain.

METHODS

This prospective study included 42 patients (28 normotensive [NT] and 14 hypertensive [HT]), 71% women with a mean age (standard deviation [SD]) of 48 (11) years undergoing bariatric surgery (BS): 22 laparoscopy Roux-en-Y gastric bypass (LRYGB) and 20 sleeve gastrectomy (SG). SG: 20. Before and 12 months post-BS, anthropometric data, BP (24-h ambulatory BP measurement), and metabolic parameters were determined. At 12 months post-BS ultrasonographic carotid assessment was performed in a subgroup of patients (22).

RESULTS

Both groups experienced significant WL (percent of excess body weight loss [%EBWL] 68%), a fall in 24-h SBP of-13 (11)/DBP-3 (7) mm Hg, and improvement in all the metabolic parameters evaluated and the homeostatic model assessment of insulin resistance (HOMA-IR). However, nondipper status remained high in NT (54%) and HT (64%) as well as 60% of the patients with carotid plaque. Additionally, in HT patients nocturnal hypertension and PP remained significantly higher, and basal fasting insulin values and the HOMA-IR score were significantly higher in those not normalizing dipper status.

CONCLUSION

Surgery-induced WL was associated with a sizeable decline in BP and metabolic parameters improvement. However, independent of the presence of hypertension, the prevalence of abnormal 24-h BP patterns remained high, and thus, cardiovascular risk continued to be high in these patients.

Association Between Cholesterol Efflux Capacity and Atherosclerotic Cardiovascular Disease in Patients With Familial Hypercholesterolemia

OBJECTIVE

Patients with familial hypercholesterolemia (FH) are at high risk for premature atherosclerotic cardiovascular disease (ASCVD), especially because of long-term exposure to high low-density lipoprotein cholesterol levels. It has been reported that low-density lipoprotein-lowering therapy delays the onset of ASCVD. However, it still remains difficult to prevent it. Therefore, novel biomarkers and therapeutic targets are necessary to evaluate and prevent atherosclerosis in FH. The aim of this study was to investigate associations of cholesterol efflux capacity with the presence of ASCVD and clinical features in patients with heterozygous FH.

APPROACH AND RESULTS

We measured cholesterol efflux capacity in 227 patients with heterozygous FH under pharmaceutical treatment. Seventy-six (33.5%) of them were known to have ASCVD. In a logistic-regression analysis adjusted for risk factors, increased efflux capacity was associated with decreased risk of ASCVD even after the addition of high-density lipoprotein cholesterol level as a covariate (odds ratio per 1-SD increase, 0.95; 95% confidence interval, 0.90-0.99; P<0.05). Decreased cholesterol efflux capacity was associated with the presence of corneal arcus after adjusting for age and sex. In addition, inverse relationships between cholesterol efflux capacity and Achilles tendon thickness, as well as carotid intima-media thickness, were observed after adjustment for age, sex, and traditional cardiovascular risk factors.

CONCLUSIONS

Cholesterol efflux capacity was independently and inversely associated with the presence of ASCVD in heterozygous FH. In view of residual risks after treatment with statins, cholesterol efflux capacity might be a novel biomarker and a therapeutic target for preventing atherosclerosis in patients with FH.

Prevalence by sex of preclinical carotid atherosclerosis in newly diagnosed type 2 diabetes

BACKGROUND AND AIMS

There is clinical trial evidence that only early, intensive risk factor control can reduce cardiovascular disease (CVD) morbidity and mortality in type 2 diabetes (T2DM). However, there is little information regarding preclinical atherosclerosis at diabetes diagnosis. We assessed carotid atherosclerosis in new-onset T2DM and control individuals without prior CVD.

METHODS AND RESULTS

In a cross-sectional case-control study, we determined intima-media thickness (IMT) and plaque (IMT ≥1.5 mm) by ultrasound at all carotid sites in new-onset T2DM patients and controls. We assessed 106 T2DM patients, median age 62 years, 46% women, 19% smokers, 54% with hypertension, and 41% with dyslipidemia and 99 non-diabetic subjects matched by age, sex, and cardiovascular risk factors. Compared to controls, T2DM patients had higher common carotid artery (CCA)-IMT (median 0.725 vs. 0.801 mm, p = 0.01), bulb-IMT (0.976 vs. 1.028 mm, p = 0.12), and internal carotid artery (ICA)-IMT (0.727 vs. 0.802 mm, p = 0.04). The prevalence of total plaque (60% vs. 72%, p = 0.06), ICA plaque (20% vs. 42%, p < 0.01), and harboring ≥3 plaques (16% vs. 35% p < 0.01) was also higher in T2DM. Plaque score (sum of maximum plaque heights) was also higher (p < 0.01) in T2DM. Diabetic women showed more advanced carotid atherosclerosis than diabetic men when they were compared with their respective non-diabetic counterparts.

CONCLUSIONS

There is a high prevalence of preclinical atherosclerosis (carotid plaque presence and burden) in new-onset T2DM subjects, especially in women. Early, still reversible, preclinical atherosclerosis may explain in part why early intervention is effective to prevent CVD in this patient population.

Hypercholesterolemia and reduced HDL-C promote hematopoietic stem cell proliferation and monocytosis: studies in mice and FH children

Previous studies have shown that mice with defects in cellular cholesterol efflux show hematopoietic stem cell (HSPC) and myeloid proliferation, contributing to atherogenesis. We hypothesized that the combination of hypercholesterolemia and defective cholesterol efflux would promote HSPC expansion and leukocytosis more prominently than either alone. We crossed Ldlr(-/-) with Apoa1(-/-) mice and found that compared to Ldlr(-/-) mice, Ldlr(-/-)/Apoa1(+/-) mice, with similar LDL-cholesterol levels but reduced HDL-cholesterol (HDL-C) levels, had expansion of HSPCs, monocytosis and neutrophilia. Ex vivo studies showed that HSPCs expressed high levels of Ldlr, Scarb1 (Srb1), and Lrp1 and were able to take up both native and oxidized LDL. Native LDL directly stimulated HSPC proliferation, while co-incubation with reconstituted HDL attenuated this effect. We also assessed the impact of HDL-C levels on monocytes in children with familial hypercholesterolemia (FH) (n = 49) and found that subjects with the lowest level of HDL-C, had increased monocyte counts compared to the mid and higher HDL-C levels. Overall, HDL-C was inversely correlated with the monocyte count. These data suggest that in mice, a balance of cholesterol uptake and efflux mechanisms may be one factor in driving HSPC proliferation and monocytosis. Higher monocyte counts in children with FH and low HDL-cholesterol suggest a similar pattern in humans.

Accelerated subclinical coronary atherosclerosis in patients with familial hypercholesterolemia

OBJECTIVES

We determined the extent, severity, distribution and type of coronary plaques in cardiac asymptomatic patients with familial hypercholesterolemia (FH) using computed tomography (CT).

BACKGROUND

FH patients have accelerated progression of coronary artery disease (CAD) with earlier major adverse cardiac events. Non-invasive CT coronary angiography (CTCA) allows assessing the coronary plaque burden in asymptomatic patients with FH.

MATERIALS AND METHODS

A total of 140 asymptomatic statin treated FH patients (90 men; mean age 52 ± 8 years) underwent CT calcium scoring (Agatston) and CTCA using a Dual Source CT scanner with a clinical follow-up of 29 ± 8 months. The extent, severity (obstructive or non-obstructive plaque based on >50% or <50% lumen diameter reduction), distribution and type (calcified, non-calcified, or mixed) of coronary plaque were evaluated.

RESULTS

The calcium score was 0 in 28 (21%) of the patients. In 16% of the patients there was no CT-evidence of any CAD while 24% had obstructive disease. In total 775 plaques were detected with CT coronary angiography, of which 11% were obstructive. Fifty four percent of all plaques were calcified, 25% non-calcified and 21% mixed. The CAD extent was related to gender, treated HDL-cholesterol and treated LDL-cholesterol levels. There was a low incidence of cardiac events and no cardiac death occurred during follow-up.

CONCLUSION

Development of CAD is accelerated in intensively treated male and female FH patients. The extent of CAD is related to gender and cholesterol levels and ranges from absence of plaque in one out of 6 patients to extensive CAD with plaque causing >50% lumen obstruction in almost a quarter of patients with FH.

Assessment of Carotid Atherosclerosis in Normocholesterolemic Individuals With Proven Mutations in the Low-Density Lipoprotein Receptor or Apolipoprotein B Genes

Background—

Genetic cascade screening for heterozygous familial hypercholesterolemia (FH) revealed that 15% of individuals given this diagnosis do not exhibit elevated low-density lipoprotein cholesterol (LDL-C) levels. We assessed whether cardiovascular risk for these individuals differs from that of hypercholesterolemic FH heterozygotes and unaffected relatives.

Methods and Results—

Individuals aged 18 to 55 years were recruited within 18 months after genetic screening. Three groups were studied: subjects given a molecular diagnosis of FH and with LDL-C levels at genetic screening below the 75th percentile (FH-low), subjects with FH and an LDL-C level above the 90th percentile (FH-high), and subjects without FH (no-FH). We measured carotid intima-media thickness (IMT) by ultrasonography. Differences in carotid IMT among the groups were assessed using multivariate linear regression analyses. Mean carotid IMT of 114 subjects in the FH-low group (0.623 mm; 95% CI, 0.609 to 0.638 mm) was significantly smaller than that of 162 subjects in the FH-high group (0.664 mm; 95% CI, 0.648 to 0.679 mm; P <0.001) and did not significantly differ from the mean carotid IMT in 145 subjects in the no-FH group (0.628 mm; 95% CI, 0.613 to 0.642 mm; P =0.67).

Conclusions—

Our findings suggest that the risk of cardiovascular disease in patients with FH to a large extent is related to LDL-C levels and not to the presence of a mutation per se. Consequently, this study cautiously suggests that individuals with an FH genotype without expression of hypercholesterolemia may not require a pharmaceutical intervention that is as aggressive as the standard for subjects with FH.

Plasma lecithin:cholesterol acyltransferase and carotid intima-media thickness in European individuals at high cardiovascular risk

Lecithin:cholesterol acyltransferase (LCAT) is the enzyme responsible for cholesterol esterification in plasma. LCAT is a major factor in HDL remodeling and metabolism, and it has long been believed to play a critical role in macrophage reverse cholesterol transport (RCT). The effect of LCAT on human atherogenesis is still controversial. In the present study, the plasma LCAT concentration was measured in all subjects (n = 540) not on drug treatment at the time of enrollment in the multicenter, longitudinal, observational IMPROVE study. Mean and maximum intima-media thickness (IMT) of the whole carotid tree was measured by B-mode ultrasonography in all subjects. In the entire cohort, LCAT quartiles were not associated with carotid mean and maximum IMT (P for trend 0.95 and 0.18, respectively), also after adjustment for age, gender, HDL-cholesterol (HDL-C), and triglycerides. No association between carotid IMT and LCAT quartiles was observed in men (P=0.30 and P=0.99 for mean and maximum IMT, respectively), whereas carotid IMT increased with LCAT quartiles in women (P for trend 0.14 and 0.019 for mean and maximum IMT, respectively). The present findings support the concept that LCAT is not required for an efficient reverse cholesterol transport and that a low plasma LCAT concentration and activity is not associated with increased atherosclerosis.

Epicardial fat gene expression after aerobic exercise training in pigs with coronary atherosclerosis: relationship to visceral and subcutaneous fat

Epicardial adipose tissue (EAT) is contiguous with coronary arteries and myocardium and potentially may play a role in coronary atherosclerosis (CAD). Exercise is known to improve cardiovascular disease risk factors. The purpose of this study was to investigate the effect of aerobic exercise training on the expression of 18 genes, measured by RT-PCR and selected for their role in chronic inflammation, oxidative stress, and adipocyte metabolism, in peri-coronary epicardial (cEAT), peri-myocardial epicardial (mEAT), visceral abdominal (VAT), and subcutaneous (SAT) adipose tissues from a castrate male pig model of familial hypercholesterolemia with CAD. We tested the hypothesis that aerobic exercise training for 16 wk would reduce the inflammatory profile of mRNAs in both components of EAT and VAT but would have little effect on SAT. Exercise increased mEAT and total heart weights. EAT and heart weights were directly correlated. Compared with sedentary pigs matched for body weight to exercised animals, aerobic exercise training reduced the inflammatory response in mEAT but not cEAT, had no effect on inflammatory genes but preferentially decreased expression of adiponectin and other adipocyte-specific genes in VAT, and had no effect in SAT except that IL-6 mRNA went down and VEGFa mRNA went up. We conclude that 1) EAT is not homogeneous in its inflammatory response to aerobic exercise training, 2) cEAT around CAD remains proinflammatory after chronic exercise, 3) cEAT and VAT share similar inflammatory expression profiles but different metabolic mRNA responses to exercise, and 4) gene expression in SAT cannot be extrapolated to VAT and heart adipose tissues in exercise intervention studies.

Predictors of the intima-media thickness of carotid artery in asymptomatic newly detected severe hypercholesterolemic patients

BACKGROUND

Data about predictors of intima-media thickness (IMT) of common carotid artery (CCA) in asymptomatic subjects with newly detected severe hypercholesterolemia is scarce.

AIM

This research is aimed at studying the predictors of the IMT of CCA among basic atherogenic risk biomarkers - lipid [total cholesterol (TC), triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein (LDL) cholesterol, Apolipoprotein-B, Apolipoprotein-Ai, Apolipoprotein-B/A(1) index] and non-lipid, [asymmetric dimethylarginine (ADMA), total homocysteine, cell adhesion molecules] in asymptomatic subjects with newly detected severe hypercholesterolemia.

METHODS

Two hundred and fifty asymptomatic patients with severe, newly hypercholesterolemia and 200 controls were evaluated. Hypercholesterolemia was defined as TC > 7.5 mm and LDL cholesterol > 4.9 mm. The ADMA and cell adhesion molecules were determined by ELISA and total homocysteine by high-performance liquid chromatography.

RESULTS

There was significant difference between the two groups in respect to all lipid biomarkers (P<0.001). Hypercholesterolemic patients had significantly higher level of ADMA, sVCAM-1, sICAM-1, IMT (P<0.001), whereas no significant difference was found between two groups with respect to total homocysteine, P-selectin and E-selectin (P>0.05). A strong positive correlation between IMT mean and age (r(xy) = 0.714; P<0.001), Apolipoprotein-B (r(xy) = 0.706; r(xy) < 0.001), Apolipoprotein-B/A(1) (r(xy) = 0.324; P<0.001), ADMA (r(xy) = 0.603; P<0.001) was found. The subsequent linear and multiple regression analysis selected age and Apolipoprotein-B as most significant factors in relation to IMT mean. Apolipoprotein-B is a better factor for assessment of risk, as LDL cholesterol underestimates the risk in asymptomatic subjects with newly detected severe hypercholesterolemia, until more rapid and feasible methods for measurement of small and dense LDL are available.

Appropriate use criteria for carotid intima media thickness testing

The Society of Atherosclerosis Imaging and Prevention, in collaboration with the International Atherosclerosis Society, conducted an appropriate use review of common clinical scenarios where carotid intima media thickness testing may be considered. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Thirty-three clinical scenarios were developed by a writing committee and scored by a separate technical panel on a scale of 1-9 to designate appropriate use, inappropriate use, or uncertain use. Clinical scenarios included the clinical application of CIMT for risk assessment in the absence of known coronary heart disease, risk assessment in patients with known CHD, and serial CIMT imaging for monitoring of CHD risk status. Appropriate indications were largely clustered within the detection of CHD risk among intermediate risk patients, metabolic syndrome, and older patients. There were no appropriate indications for serial testing. Inappropriate indications generally were seen among use of CIMT in low risk patients, and high risk patients. This document is intended to provide a practical guide to clinicians and promote optimal use of testing which includes both the avoidance of under and over testing. It is intended that these criteria will be updated as the evidence on CIMT imaging continues to evolve.

Soluble fms-like tyrosine kinase-1 and the progression of carotid intima-media thickness – 24-month follow-up study –

BACKGROUND

The relationship between fms-like tyrosine kinase-1 (sFlt-1), a soluble receptor for vascular endothelial growth factor (VEGF), and vascular disease has not been established, so this study aimed to elucidate the association between sFlt-1 and the progression of carotid intima - media thickness (IMT) in hypertensive patients.

METHODS AND RESULTS

The 120 hypertensive patients under medical control were enrolled and 112 completed the study (age 59 ± 9 years, 57 females). Plasma VEGF and sFlt-1 levels were measured at enrollment. At baseline and 24-month visit, carotid IMT was measured and the association between sFlt-1 and IMT progression was assessed by linear regression. At baseline, age (r=0.186) and low level of high-density lipoprotein-cholesterol (HDL-C <40 mg/dl, r=0.214) were significantly related to carotid IMT. Over the 24 months, carotid IMT increased from 0.670 ± 0.089 mm to 0.696 ± 0.095 mm. There was a positive correlation between sFlt-1 tertiles and IMT change (P=0.05 by ANOVA). Upon multivariate analysis, log-transformed sFlt-1 level (β=0.137, P=0.003) and low HDL-C (β=0.048, P=0.04) were identified as predictors of IMT progression, independent of other confounding variables.

CONCLUSIONS

High sFlt-1 level is predictive of carotid IMT progression in hypertensive patients. Low HDL-C level was also associated with IMT change. These observations support a high sFlt-1 level being indicative of progression of atherosclerosis. 

Fatty acids in serum phospholipids and carotid intima-media thickness in Spanish subjects with primary dyslipidemia

BACKGROUND

Low rates of incident ischemic heart disease (IHD) and cardiac death occur in Spain despite a high prevalence of cardiovascular risk factors. High consumption of unsaturated fatty acid-rich foods, such as olive oil, nuts, and seafood, might underlie this paradox.

OBJECTIVE

We investigated whether serum phosphatidylcholine enrichment in oleic, linoleic, alpha-linolenic, and n-3 (omega-3) long-chain polyunsaturated fatty acids (as biomarkers of olive oil, seed oil, walnut, and fish intake, respectively) relate to carotid atherosclerosis in Spanish subjects at risk of IHD.

DESIGN

In a cross-sectional study, we measured fatty acid concentrations in serum phosphatidylcholine and measured carotid intima-media thickness (IMT) by using ultrasound in 451 asymptomatic subjects (261 men, 190 women; mean age: 45 y) with primary dyslipidemia. Main and secondary outcomes were mean and maximum IMT in the common carotid artery (CCA) and other carotid segments, respectively.

RESULTS

Phosphatidylcholine fatty acid composition was similar to that reported for other Spanish populations. Multiple regression analyses showed that proportions of oleic and docosahexaenoic acids were inversely related to mean CCA IMT (P < 0.02, all) after adjustment for several confounders. In similar models, alpha-linolenic acid related inversely to mean and maximum internal carotid artery IMT (P < 0.05 for all). Linoleic and eicosapentaenoic acids were unrelated to IMT.

CONCLUSIONS

Higher phospholipid proportions of oleic, alpha-linolenic, and docosahexaenoic acids showed inverse associations with IMT at specific carotid segments in subjects with primary dyslipidemia. High intakes of healthy fats might explain, in part, the Spanish paradox of low IHD rates in the face of a high burden of cardiovascular risk factors.

Inflammatory and thrombotic processes are associated with vascular dysfunction in children with familial hypercholesterolemia

BACKGROUND

Evidence suggests that children with familial hypercholesterolemia (FH) have endothelial dysfunction. Inflammatory and haemostatic abnormalities are associated with advanced atherosclerosis and increased cardiovascular events. However, it is unknown whether these abnormalities present in FH children and contribute to their vascular dysfunction.

METHODS AND RESULTS

We studied 38 children with FH (19 males, 19 females aged 14.8+/-0.9 years mean+/-S.E.) and 41 healthy children (controls; 22 males, 19 females aged 15.4+/-0.7 years). Endothelium-dependent reactive hyperemia (RH%) and endothelium-independent nitrate hyperemia dilatation (NH%) were measured by strain gauge plethysmography. Inflammatory and haemostatic parameters were assessed by ELISA. RH% and NH% were significantly reduced in FH compared to controls (91.3+/-9.3% vs. 120.4+/-10.6% and 53.6+/-3.8% vs. 74.5+/-7.4%, p<0.05 for both). Total cholesterol and lipoprotein (a) were increased in FH children compared to controls (282.3+/-8.8 mg/dl vs. 163.8+/-4.6 mg/dl and 11.0[4.6, 30.7]mg/dl vs. 5.24[2.63, 11.0]mg/dl median [IQR] respectively; p<0.001 for both). Intercellular cell adhesion molecule (ICAM-1) and interleukin 1 beta (IL-1 beta) serum levels were increased in FH compared to controls (p<0.05 and <0.001, respectively). Plasminogen activator inhibitor 1 (PAI-1) levels were also higher in FH children (p<0.001). Multivariate analysis revealed that reactive hyperemia was independently associated with nitrate-dependent reactive hyperemia (beta=0.597(0.199), p<0.01), PAI-1(beta=-6.78(2.65), p<0.05), log IL-1 beta (beta=-102.8 (30.2), p<0.01), age (beta=-5.06 (2.35), p<0.05) and FH status (beta=-25.2(10.6), p<0.05) (R(2) for the model: 0.63, p=0.001).

CONCLUSIONS

Inflammatory and haemostatic abnormalities are present in FH children and contribute to the endothelial dysfunction observed in these children.

Carotid atherosclerosis in familial combined hyperlipidemia associated with the APOB/APOA-I ratio

OBJECTIVES

The effects of risk factors on carotid atherosclerosis in familial combined hyperlipidemia (FCHL) remain unclear. We assessed carotid intima-media thickness (IMT) and plaque in relation to classical risk factors and apolipoprotein A-I (apoA-I) and B (apoB) levels in patients with FCHL.

METHODS AND RESULTS

We included 131 unrelated FCHL patients (27 with prior cardiovascular disease (CVD)) diagnosed by standard criteria and 190 age- and sex-matched control subjects. Cardiovascular risk factors were assessed and IMT in the far wall of all carotid segments and plaque burden were determined in FCHL patients and controls. All carotid measurements were increased in FCHL patients compared to controls (P<0.001), irrespective of CVD status. For asymptomatic FCHL, the adjusted difference in mean common carotid IMT was 0.08 mm, corresponding to approximately 16 years of physiological IMT increase. By multivariate analysis in a model with all risk factors, inclusive of the metabolic syndrome, independent associations of IMT were age, the apoB/apoA-I ratio, systolic blood pressure, fasting glucose, family history of CVD and total/HDL cholesterol ratio (r(2)=0.475, P<0.001). The strongest determinant of IMT was the apoB/apoA-I ratio (beta=0.422, P<0.001).

CONCLUSIONS

Patients with FCHL have increased carotid IMT that is strongly related to the apoB/apoA-I ratio, a measure of overall lipid abnormalities. The findings support the atherogenicity of the lipid phenotype in FCHL beyond associated risk factors. They also have implications for diagnosis and management of CVD risk in this condition.

Familial hypercholesterolaemia in Portugal

Familial hypercholesterolaemia (FH) is characterised clinically by an increased level of circulating LDL cholesterol that leads to lipid accumulation in tendons and arteries, premature atherosclerosis and increased risk of coronary heart disease (CHD). Although Portugal should have about 20,000 cases, this disease is severely under-diagnosed in our country, this being the first presentation of Portuguese data on FH. A total of 602 blood samples were collected from 184 index patients and 418 relatives from several centres throughout Portugal. Fifty-three different mutations were found in 83 index patients, 79 heterozygous and 4 with two defective LDLR alleles. Additionally, 4 putative alterations were found in 8 patients but were not considered mutations causing disease, mainly because they did not co-segregate with hypercholesterolaemia in the families. Three unrelated patients were found to be heterozygous for the APOB(3500) mutation and two unrelated patients were found to be heterozygous for a novel mutation in PCSK9, predicted to cause a single amino acid substitution, D374H. Cascade screening increased the number of FH patients identified genetically to 204. The newly identified FH patients are now receiving counselling and treatment based on the genetic diagnosis. The early identification of FH patients can increase their life expectancy and quality of life by preventing the development of premature CHD if patients receive appropriate pharmacological treatment.

Carotid atherosclerosis and vascular age in the assessment of coronary heart disease risk beyond the Framingham Risk Score

OBJECTIVES

To assess how ultrasound measurements of carotid intima-media thickness (CIMT) and plaque burden compare with the Framingham Risk Score (FRS) in a clinical setting.

METHODS AND RESULTS

In a cross-sectional study, we determined CIMT and plaque in 409 asymptomatic, non-diabetic hyperlipidemic subjects (242 men, age 49+/-11 years) who were assessed for risk factors and classified into FRS categories: 10-year risk < or =5% (n=191), 6-20% (n=176), and >20% (n=42). Percentiles of CIMT and plaque height and regression equations of CIMT against age obtained in 250 controls subjects were used to define atherosclerosis and estimate vascular age, respectively. There was a wide dispersion of CIMT for each FRS category. CIMT values were discordant in 242 (59%) subjects, 80% of them showing more atherosclerosis than predicted. Smoking and the metabolic syndrome explained part of the discrepancies in the intermediate-risk group. Triglycerides, homocysteine, and lipoprotein(a) did not predict atherosclerotic burden. Mean vascular age was 14.5 years older than chronological age.

CONCLUSIONS

Carotid atherosclerosis findings readjust FRS categories in many asymptomatic subjects. Both carotid atherosclerotic burden and vascular age may be used to refine CHD risk and tailor preventive treatment beyond the FRS.

Association between apolipoprotein E genotype and carotid intima-media thickness may suggest a specific effect on large artery atherothrombotic stroke

BACKGROUND AND PURPOSE

Apolipoprotein E genotype (APOE) influences cholesterol levels and ischemic heart disease. Although there is no convincing overall association with ischemic stroke, APOE may influence large artery (atherothrombotic) stroke, for which carotid intima-media thickness (CIMT) is an informative intermediate phenotype. We therefore performed a systematic review and meta-analysis of the association between APOE and CIMT.

METHODS

We sought all published studies assessing the association between APOE and CIMT. From each study, we extracted available data on study methods, subjects' characteristics, and mean (and standard deviation) CIMT for each genotype or genotype group. We calculated study-specific and random effects pooled differences in mean CIMT between genotype groups, and assessed heterogeneity between studies and predefined subgroups using I(2) and chi(2) statistics.

RESULTS

Meta-analysis of 22 published studies (30,879 subjects) showed a significant association between APOE and CIMT (pooled mean difference epsilon 4- versus epsilon 2-allele containing genotypes 46 microm, 95% CI 29 to 62, P<0.00001). We found evidence of small study (mainly publication) bias, with a diminished (but still highly statistically significant) association in studies of >1000 subjects (pooled mean difference 17 microm, 95% CI 12 to 23, P<0.00001). The association was larger among high vascular risk and eastern Asian populations, but this may simply reflect the smaller size of these studies.

CONCLUSIONS

Our results show a clear association of APOE with CIMT, even though publication bias means that this is overestimated by the published literature. These findings suggest the possibility of a specific association with large artery ischemic stroke.

Absence of stearoyl-CoA desaturase-1 ameliorates features of the metabolic syndrome in LDLR-deficient mice

A combination of the interrelated metabolic risk factors obesity, insulin resistance, dyslipidemia, and hypertension, often described as the "metabolic syndrome," is known to increase the risk of developing cardiovascular disease and diabetes. Stearoyl-coenzyme A desaturase (SCD) activity has been implicated in the metabolic syndrome, but detailed studies of the beneficial metabolic effects of SCD deficiency have been limited. Here, we show that absence of the Scd1 gene product reduces plasma triglycerides and reduces weight gain in severely hyperlipidemic low density lipoprotein receptor (LDLR)-deficient mice challenged with a Western diet. Absence of SCD1 also increases insulin sensitivity, as measured by intraperitoneal glucose and insulin tolerance testing. SCD1 deficiency dramatically reduces hepatic lipid accumulation while causing more modest reductions in plasma apolipoproteins, suggesting that in conditions of sustained hyperlipidemia, SCD1 functions primarily to mediate lipid stores. In addition, absence of SCD1 partially ameliorates the undesirable hypertriglyceridemic effect of antiatherogenic liver X receptor agonists. Our results demonstrate that constitutive reduction of SCD activity improves the metabolic phenotype of LDLR-deficient mice on a Western diet.

High-density lipoprotein-cholesterol and risk of stroke and carotid atherosclerosis: a systematic review

BACKGROUND AND PURPOSE

Epidemiological studies have found no relationship between total cholesterol and stroke risk, but little attention has been paid to high-density lipoprotein-cholesterol (HDL-C).

METHODS

We performed a systematic PubMed literature search for epidemiological studies that examined the association between HDL-C level and stroke or carotid intima-media thickness (IMT).

RESULTS

We identified 18 studies on the relationship between HDL-C and stroke risk and 37 on HDL-C and carotid IMT. Eight of ten prospective cohort studies (n=238,739) and three of eight case-control studies (n=3604 cases, 8220 controls) supported an association between elevated HDL-C level and decreased risk of stroke. Prospective cohort studies reporting on relative risk per unit increase in HDL-C showed an 11-15% decreased stroke risk per 10-mg/dl increase in HDL-C. Of 37 studies on carotid IMT, 31 reported cross-sectional, one longitudinal, and five both cross-sectional and longitudinal associations between HDL-C level and carotid IMT. Of 36 cross-sectional studies (n=51,288), 20 showed an inverse association between HDL-C level and carotid IMT. Of six longitudinal studies (n=20,065), three showed no association, one showed a weak association in a subgroup of white women and two showed a significant inverse relationship between HDL-C level and carotid IMT. Pooled estimates could not be calculated because of the variation in study designs and analysis.

CONCLUSIONS

The weight of evidence in the literature supports an inverse association between HDL-C level and stroke or carotid atherosclerosis, but more data are needed to firmly establish this protective effect.

Fish consumption and early atherosclerosis in middle-aged men

To investigate the association between fish consumption and early atherosclerosis, we analyzed the relationship between fish consumption and average intima-media thickness (AveIMT) by carotid ultrasound in middle-aged Japanese men. Participants were 250 randomly selected, community-based Japanese men aged 40 to 49 years without a prior history of cardiovascular disease. AveIMT was calculated from the mean of 1-cm lengths of both the right and the left carotid arteries at 8 locations. A lifestyle survey was carried out using a self-administered questionnaire including the frequency of fish intake. There were 147 men in the fewer than 4 times per week fish consumption group and 103 men in the 4 or more times per week group. The mean AveIMT was significantly higher in the low fish consumption group than in the high fish consumption group (0.623+/-0.068 vs 0.605+/-0.065 mm, P=.03). After adjustment for age, waist circumference, pack-years of smoking, alcohol consumption, diabetes, and lipid-lowering medications, the significant difference in the AveIMT between the 2 groups remained. However, after further adjustment for low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and C-reactive protein in the model, the significant difference disappeared. Fish consumption may be protective against early atherosclerosis in middle-aged men, probably through its beneficial effects on inflammation.

Effect of torcetrapib on carotid atherosclerosis in familial hypercholesterolemia

BACKGROUND

Torcetrapib, an inhibitor of cholesteryl ester transfer protein, may reduce atherosclerotic vascular disease by increasing levels of high-density lipoprotein (HDL) cholesterol.

METHODS

A total of 850 patients with heterozygous familial hypercholesterolemia underwent B-mode ultrasonography at baseline and at follow-up to measure changes in carotid intima-media thickness. The patients completed an atorvastatin run-in period and were subsequently randomly assigned to receive either atorvastatin monotherapy or atorvastatin combined with 60 mg of torcetrapib for 2 years.

RESULTS

After 24 months, in the atorvastatin-only group, the mean (+/-SD) HDL cholesterol level was 52.4+/-13.5 mg per deciliter and the mean low-density lipoprotein (LDL) cholesterol level was 143.2+/-42.2 mg per deciliter, as compared with 81.5+/-22.6 mg per deciliter and 115.1+/-48.5 mg per deciliter, respectively, in the torcetrapib-atorvastatin group. During the study, average systolic blood pressure increased by 2.8 mm Hg in the torcetrapib-atorvastatin group, as compared with the atorvastatin-only group. The increase in maximum carotid intima-media thickness, the primary measure of efficacy, was 0.0053+/-0.0028 mm per year in the atorvastatin-only group and 0.0047+/-0.0028 mm per year in the torcetrapib-atorvastatin group (P=0.87). The secondary efficacy measure, annualized change in mean carotid intima-media thickness for the common carotid artery, indicated a decrease of 0.0014 mm per year in the atorvastatin-only group, as compared with an increase of 0.0038 mm per year in the torcetrapib-atorvastatin group (P=0.005).

CONCLUSIONS

In patients with familial hypercholesterolemia, the use of torcetrapib with atorvastatin, as compared with atorvastatin alone, did not result in further reduction of progression of atherosclerosis, as assessed by a combined measure of carotid arterial-wall thickness, and was associated with progression of disease in the common carotid segment. These effects occurred despite a large increase in HDL cholesterol levels and a substantial decrease in levels of LDL cholesterol and triglycerides. (ClinicalTrials.gov number, NCT00136981 [ClinicalTrials.gov].).

Serum asymmetric dimethylarginine negatively correlates with intima-media thickness in early-onset atherosclerosis

BACKGROUND

Asymmetric dimethylarginine (ADMA) assumes a significant role in atherosclerosis by inhibiting the endothelial nitric oxide synthase (eNOS). Moreover, ADMA inhibits the inducible NOS (iNOS), the isoform that triggers atherosclerosis via peroxynitrite formation. Therefore, we investigated whether ADMA is a risk or protective factor in the atherosclerotic process. Intima-media thickness (IMT) of the common carotid artery, a surrogate for vascular diseases, was chosen as the outcome variable of interest.

METHODS

Sixty patients younger than 55 years having at least 30% stenosis of the internal carotid artery and 30 age- and gender-matched controls were recruited at a community-based neurosonological laboratory. We investigated relatively young patients to circumvent the confounding effect age has in the development of atherosclerosis.

RESULTS

The IMT showed a negative correlation with ADMA upon analysis of the pooled data (Spearman correlation coefficient -0.300, p = 0.0041) and the atherosclerotic stratum (Spearman correlation coefficient -0.323, p = 0.012). A multiple linear regression model containing all determinant factors of IMT previously identified by simple regression was used to further quantify the relationship between IMT and ADMA. The negative association between IMT and ADMA remained statistically significant (beta: -0.510, CI: -0.894, -0.127; p = 0.010), furthermore it was even stronger in the atherosclerotic stratum (beta: -0.67, CI: -1.16, -0.18; p = 0.008).

CONCLUSIONS

A minimal increase in ADMA concentration may be protective by inhibiting iNOS but not eNOS in states where iNOS is induced, e.g. inflammation accompanying atherosclerosis.

The effect of 24 months of combination statin and extended-release niacin on carotid intima-media thickness: ARBITER 3

OBJECTIVE

The ARBITER 2 trial showed that extended-release niacin (ERN) when added to statin monotherapy slowed the progression of carotid atherosclerosis over 12 months. Whether longer treatment with ERN would have a greater effect on carotid intima-media thickness (CIMT) is unknown.

RESEARCH DESIGN AND METHODS

We examined the long-term effects of ERN on high density lipoprotein (HDL-C) cholesterol and CIMT during 12-24 months treatment with ERN in ARBITER 2 participants who were either continued or were crossed over (from placebo) to ERN 1000 mg daily.

MAIN OUTCOME MEASURES

Among 149 subjects completing ARBITER 2, 130 (88%) enrolled in ARBITER 3. The prespecified primary endpoints were the within-group change in CIMT and HDL-C in patients receiving placebo for 12 months (n = 71), ERN for 12 months (comprised of subjects from ERN treatment during ARBITER 2 (n = 78) and those crossed over to ERN from placebo after ARBITER 2 (n = 47)), and ERN for 24 months spanning ARBITER 2 and 3 (n = 57). Five subjects discontinued the study due to flushing side effects. The study was completed by 104 subjects (47 crossed over from placebo; 57 with ERN continued from ARBITER 2).

RESULTS

HDL-C increased in the ERN group from 39.5 +/- 6.7 to 48.6 +/- 13.3 mg/dl (p < 0.001) along with modest reductions in LDL-C and TG. Among 125 participants treated with ERN for 12 months, there was a net regression of CIMT of -0.027 +/- 0.011 mm (p < 0.001 vs. placebo). Among 57 participants treated with ERN for 24 months, there was additional significant regression of CIMT of -0.041 +/- 0.021 mm (p = 0.001 vs. placebo). Controlling for changes in LDL and triglycerides, only changes in HDL-C were independently associated with regression of CIMT (beta = -0.25; p = 0.001).

CONCLUSION

When added to statin therapy, ERN significantly increases HDL-C and induces atherosclerosis regression measured by CIMT over 24 months. Limitations to this study include its open-label design and the inability to relate CIMT effects to clinical outcomes.