Large HDL Research Articles

Amount of hepatic fat predicts cardiovascular risk independent of insulin resistance among Hispanic-American adolescents.

BackgroundNonalcoholic fatty liver disease (NAFLD) has emerged as the major pediatric chronic liver disease, and it is estimated to affect more than one third of obese children in the U.S. Cardiovascular complications are a leading cause of increased mortality in adults with NAFLD and many adolescents with NAFLD already manifest signs of subclinical atherosclerosis including increased carotid intima-media thickness.MethodsVolume of intrahepatic fat was assessed in 50 Hispanic-American, overweight adolescents, using Magnetic Resonance Spectroscopy. Lipoprotein compositions were measured using Nuclear Magnetic Resonance.ResultsPlasma triglycerides (TG) (p = 0.003), TG/HDL ratio (p = 0.006), TG/apoB ratio (p = 0.011), large VLDL concentration (p = 0.019), VLDL particle size (p = 0.012), as well as small dense LDL concentration (p = 0.026) progressively increased across higher levels of hepatic fat severity, while large HDL concentration progressively declined (p = 0.043). This pattern of associations remained even after controlling for gender, BMI, visceral fat, and insulin resistance.ConclusionsOur findings suggest that increased hepatic fat is strongly associated with peripheral dyslipidemia and the amount of fat in the liver may influence cardiovascular risk. Further studies are needed to longitudinally monitor dyslipidemia in children with NAFLD and to examine whether the reduction of hepatic fat would attenuate their long-term CVD risk.

Abstract 339: Hyperhomocysteinemia Reduces Large HDL Particle and EL Expression via Hypomethylation Related Mechanism in Mice

Hyper-homocysteinemia (HHcy) has been identified as an independent risk factors of cardiovascular diseases (CVD). We previous reported HHcy is associated with reduced HDL-cholesterol and decreased large HDL particle in mouse and human CVD. Here, we investigated underlying mechanism of homocysteine (Hcy)-related HDL biosynthesis and degradation. We examined protein/gene expression, activities of four HDL-degradation related lipases including endothelial lipase (EL), lipoprotein lipase (LPL), hepatic lipase (HL), and pancreatic lipase (PL). Severe HHcy (98.4±22 μM) was established in cystathionine betasynthase-gene mutant mice ( Cbs +/- ), moderate HHcy (23.5±5 μM) was also developed in Cbs +/+ mice, both fed a high methionine (HM) diet for 8-week. Moderate and severe HHcy increased protein levels of EL in aorta (204% and 319%), lung (201% and 264%), and decreased LPL in aorta (98% and 34%), lung (99% and 61%), spleen (98% and 51%). HL and PL protein levels were not changed by HHcy. Activities of overall lipases were increased in moderate and severe HHcy in aorta (19.8±5.2 and 27.5±7.1, arbitrary unit), plasma (64.3±5.5 and 126.5±26.2), adipose (147.0±8.9 and 210.9±38.9) and liver (160.5±41.3 and 276.2±51.3). Next, we examined tissue levels of Hcy, and its metabolites (SAM, SAH) in heart, lung, brain, spleen, kidney and liver from wild type mice. Tissue expression profile of Hcy degradation and synthesis-related enzymes were established by database mining analysis. We found that mRNA levels of EL, HL, and PL were positively correlated with Hcy and negatively correlated with SAM/SAH ratio, which indicated of methylation status. In contrast, LPL mRNA levels were negatively correlated with Hcy and positively correlated with SAM/SAH ratio. These data suggest that EL, HL, PL gene expression may be induced by Hcy-related hypomethylation. We identified a large CpG island with 113 CG dinucleotide pairs in human EL promoter region, where four HDL-related single nucleotide polymorphisms (SNPs) was overlapping with CpG containing transcription factor consensus element. Our study suggests that HHcy inhibits HDL biosynthesis, promotes HDL degradation via EL induction and DNA hypomethylation related mechanisms.

Abstract 124: HDL Particles and HDL Functions

Introduction: The role of HDL in CVD risk is not fully understood. Hypothesis: We tested the hypothesis that HDL functions are significantly associated with HDL subpopulation profile. Methods: Lipoproteins, including apoA-I-containing HDL particles, cell-cholesterol efflux (Global, ABCA1- and SRB1-mediated) and HDL Inflammatory Index were measured in a total of 289 subjects. These included 60 CHD patients, 109 subjects with either abnormal lipids (high triglycerides/low HDL or elevated β-sitosterol) or increased levels of the inflammatory markers C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen, or myeloperoxidase (MPO), as well as 120 controls. Results: Global efflux was highly correlated with ABCA1-mediated efflux (r=0.921). Cholesterol efflux via the ABCA1 pathway was significantly correlated with small prebeta-1 HDL particles (r=0.762). CHD patients had significantly higher preβ-1 level than controls; however, per-particle prebeta-1 HDL effluxed 41% less cholesterol in CHD patients as compared to controls, resulting in no significant difference in overall efflux capacity between cases and controls. Cholesterol efflux via the SRB1 pathway was significantly correlated with large α-1 (r=0.784) and α-2 (r=0.460) HDL particles. These two large HDL particles effluxed about 82% of cell cholesterol via the SRB1 pathway. There was no significant difference in SRB1-mediated cholesterol efflux between CHD cases and controls. The HDL Inflammatory Index (HII) was significantly higher (unfavorable) in CHD cases than in controls and was significantly (inversely) associated with α-2 HDL particles (r=454). Increased levels of β-sitosterol significantly altered the HDL subpopulation profile and increased HII. Moreover, HII was not correlated with the concentrations of CRP, SAA, fibrinogen and MPO. Conclusion: HDL subpopulation profile is a major determinant of HDL’s overall cholesterol-efflux capacity. Efflux capacity of preβ-1 particles are compromised in CHD patients by yet unknown factor(s). HDL Inflammatory Index correlates with HDL subpopulation profile, but not with markers of inflammation in plasma.

Abstract 128: Recombinant Lecithin Cholesterol Acyltransferase Generates Mature High Density Lipoprotein with Increased Capacity to Efflux Cholesterol via ABCG1 in Cynomolgus Monkeys

Introduction: Lecithin cholesterol acyltransferase (LCAT) esterifies free cholesterol to cholesteryl esters on the HDL particle and is considered a key component of reverse cholesterol transport. We have developed a recombinant human LCAT fusion protein with high LCAT activity and characterized the effects of this molecule on lipoprotein metabolism and cholesterol efflux in cynomolgus monkeys. Methods: Cynomolgus monkeys received a single injection of rhLCAT at 0, 0.5, 1, or 5 mpk. Blood samples were drawn for analysis at pre-dose and up to 5 days after administration. HDL-C and apoAI were measured using standard clinical analyzers, apoE was measured by ELISA, and rhLCAT was measured by MSD immunoassay. ApoAI containing HDL subfractions were determined by two-dimensional non-denaturing gradient gel electrophoresis as described in the literature. Cholesterol efflux was measured ex vivo from ABCA1, ABCG1, or SRB1 transfected BHK cells, or J774 mouse macrophages using apoB depleted serum. Results: After administration, serum rhLCAT concentrations increased dose proportionately. HDL-C increased rapidly, beginning within the first 6 hours after dosing, and was dose dependent with maximum increases of 87% observed in the 1 and 5 mpk dose groups. ApoAI concentrations increased by as much as 15% and 21% in the 0.5 and 1 mpk groups, respectively, but decreased in the 5 mpk group by as much as 23%. The ratio of HDL-C to apoAI increased dose dependently indicating the formation of HDL particles containing increasingly more cholesterol. 2D gels confirmed the formation of large, primarily α-1, HDL particles. ApoE on HDL particles increased dose dependently with large increases observed following the 1 mpk (169%) and 5 mpk (910%) doses. Changes in the HDL particle were accompanied by changes in the ability of HDL to efflux cholesterol from cells. ABCG1 mediated efflux increased by as much as 21% and 24% in the 1 and 5 mpk dose groups, respectively. Conversely, efflux via ABCA1, SRB1, and from J774 cells was reduced dose dependently. Conclusions: The administration of rhLCAT in cynos resulted in the formation of large HDL particles that were enriched in cholesterol and ApoE. These larger particles showed increased capacity to efflux cholesterol via the ABCG1 transporter.

A multicomponent nutrient bar promotes weight loss and improves dyslipidemia and insulin resistance in the overweight/obese: chronic inflammation blunts these improvements.

This study determined if twice-daily consumption of a nutrient-dense bar intended to fill gaps in Western diets, without other dietary/lifestyle requirements, favorably shifted metabolic/anthropometric indicators of dysregulation in a healthy direction. Three 8-wk clinical trials in 43 healthy lean and overweight/obese (OW/OB) adults, who served as their own controls, were pooled for analysis. In less inflamed OW/OB [high-sensitivity C-reactive protein (hsCRP) <1.5], statistically significant decreases occurred in weight (-1.1 ± 0.5 kg), waist circumference (-3.1 ± 1.4 cm), diastolic blood pressure (-4.1 ± 1.6 mmHg), heart rate [HR; -4.0 ± 1.7 beats per minute (bpm)], triglycerides (-72 ± 38.2 mg/dl), insulin resistance (homeostatic model of insulin resistance) (-0.72 ± 0.3), and insulin (-2.8 ± 1.3 mU/L); an increase in HDL-2b (+303 ± 116 nM) and realignment of LDL lipid subfractions toward a less atherogenic profile [decreased small LDL IIIb (-44 ± 23.5 nM), LDL IIIa (-99 ± 43.7 nM), and increased large LDL I (+66 ± 28.0 nM)]. In the more inflamed OW/OB (hsCRP >1.5), inflammation was reduced at 2 wk (-0.66 mg/L), and HR at 8 wk (-3.4 ± 1.3 bpm). The large HDL subfraction (10.5-14.5 nm) increased at 8 wk (+346 ± 126 nM). Metabolic improvements were also observed in lean participants. Thus, favorable changes in measures of cardiovascular health, insulin resistance, inflammation, and obesity were initiated within 8 wk in the OW/OB by replacing deficiencies in Western diets without requiring other dietary or lifestyle modifications; chronic inflammation blunted most improvements.

In This Issue

HomeCirculation ResearchVol. 116, No. 7In This Issue Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBIn This Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published27 Mar 2015https://doi.org/10.1161/RES.0000000000000053Circulation Research. 2015;116:1097Small HDL Particles Export Cholesterol via ABCA1 (p 1133)Download figureDownload PowerPointHigh density lipoproteins (HDLs) may be “good” cholesterols, but Du et al discover which are the best of the best.Circulating HDLs collect cholesterol exported from cells and ferry it to the liver for excretion in the bile. Because of this property high HDL levels are believed to protect against cardiovascular disease. However, HDLs are a heterogeneous population of particles and it is not clear whether some are more efficient transporters than others. Moreover, the relative efficiency of the cellular exporters, ABCA1 and ABCG1, which transfer cholesterol from inside cells to the awaiting transporter, has not been determined. Hence, Du and colleagues examined the cholesterol transporting efficiency of different HDL subfractions and they found that the smallest particles, HDL3b and 3c, along with un-loaded apoA1—the main protein component of HDL—are much more efficient transporters of cholesterol from cells in culture than the large HDL particles. They also found the more efficient HDL particles export cholesterol via ABCA1 rather than ABCG1. Together the results suggest that cardioprotective therapies aimed at reducing tissue cholesterol levels might work best if they specifically boost small HDLs and the activity of ABCA1.IncRNA-MIAT and Microvascular Dysfunction (p 1143)Download figureDownload PowerPointYan et al identify the long non- coding RNA MIAT as a proangiogenic factor in diabetic retinopathy.Angiogenesis is essential for tissue growth, development, and wound healing, but it can also be detrimental in diseases such as cancer or diabetic retinopathy. A better understanding of the processes that regulate angiogenesis may therefore reveal ways to control it in a variety of clinical scenarios. To search for novel angiogenic factors that regulate pathological retinal angiogenesis associated with diabetes, Yan and colleagues focused on long, noncoding RNAs (lncRNAs)—RNAs of 200 nucleotides or more that regulate gene expression. They found that MIAT (myocardial infarction associated transcript) is upregulated in the retinas of patients and rats with diabetes as well as in endothelial cells treated with high levels of glucose. The proangiogenic factor VEGF was also increased in the diabetic rat retinas, and the team showed that knocking down MIAT reduced retinal VEGF expression, improved vascular abnormalites as well as visual function. The team also provides evidence to suggest that MIAT promotes VEGF expression by binding and inhibiting a microRNA that normally suppresses VEGF. The finding that MIAT inhibition can improve diabetes-induced retinal microvascular abnormalities suggests this lncRNA could be a target for treating retinopathy, which remains one of the most significant secondary complications of advanced diabetes.Coronary NET Burden and DNase Activity in STE-ACS (p 1182)Download figureDownload PowerPointMangold et al discover that higher levels of neutrophil NETs in a coronary thrombus are associated with more severe infarction.Formation of a large thrombus after acute plaque rupture leads to poor tissue perfusion and is associated with high morbidity and mortality Researchers are therefore investigating ways to rapidly breakdown such thrombi to re-establish blood flow in affected patients. Mangold and colleagues now suggest that one method could be to eliminate chromatin NETs—or neutrophil extracellular traps—from the thrombi. Neutrophils release their own nuclear DNA and proteins (chromatin) in the form of NETs to ensnare pathogens and stimulate proinflammatory responses—in much the same way Spiderman catches villains in his web. However the formation of these sticky, stringy traps can be problematic if they coincide with thrombus formation. By analyzing thrombi from 111 male patients with acute coronary syndrome, Mangold and colleagues found that the abundance of NETs in thrombi was positively correlated with infarct size. Encouragingly, however, the patients’ DNase level negatively correlated with both the abundance of NETs and infarct size. That is, patients with more DNase had smaller infarcts. DNase digests chromatin and the team found that the enzyme accelerated degradation of thrombi in vitro. Thus, boosting DNase activity at the site of thrombi might be a way to speed their removal. Previous Back to top Next FiguresReferencesRelatedDetails March 27, 2015Vol 116, Issue 7 Advertisement Article InformationMetrics © 2015 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000053 Originally publishedMarch 27, 2015 PDF download Advertisement

APOA5 variants predispose hyperlipidemic patients to atherogenic dyslipidemia and subclinical atherosclerosis

BackgroundTriglycerides (TG) are the initiators of the metabolic changes leading to the atherogenic dyslipidemia, which is a major inducer of atherosclerosis as a result of quantitative and qualitative changes in lipoprotein subclass distributions. We hypothesized that variation at the of APOA5 gene locus, encoding apoAV, a key regulator of TG levels, significantly affect lipoprotein subclass distributions toward a more atherogenic pattern in both hyperTG patients and dyslipemic patients. MethodsWe recruited four hundred and twenty-two subjects attending a Lipid Clinic, prior to lipid-lowering treatment. We genotyped two APOA5 variants, rs662799 (-1131T>C) and rs3135506 (S19W). Circulating lipoproteins were determined by nuclear magnetic resonance (NMR). Intima-media thickness (IMT) was evaluated using B-mode ultrasound. ResultsCarriers of the rare alleles of rs662799 and rs3135506 compared to common allele homozygotes, had a significantly proatherogenic profile of the VLDL and LDL subclasses, resulting in increased concentrations of the proatherogenic subclasses, large VLDLs (+133%, p < 0.001) and small LDLs (+34%, p = 0.014). Significant changes in smaller HDL (+71%, p = 0.032), as well as an 18% decrease in large HDL (p = 0.046), were also been observed. This atherogenic NMR subclass distribution was significantly associated with increased carotid IMT.The observed effects were significantly stronger in patients with a BMI ≥ 25 kg/m2 and in male and female patients with a waist circumference ≥90 cm or ≥85 cm, respectively. ConclusionIn a dyslipemic population, genetic variants of APOA5 modulate lipoprotein subclass distributions, inducing an atherogenic profile associated with IMT defined subclinical atherosclerosis.

Multi-omic signature of body weight change: results from a population-based cohort study.

BackgroundExcess body weight is a major risk factor for cardiometabolic diseases. The complex molecular mechanisms of body weight change-induced metabolic perturbations are not fully understood. Specifically, in-depth molecular characterization of long-term body weight change in the general population is lacking. Here, we pursued a multi-omic approach to comprehensively study metabolic consequences of body weight change during a seven-year follow-up in a large prospective study.MethodsWe used data from the population-based Cooperative Health Research in the Region of Augsburg (KORA) S4/F4 cohort. At follow-up (F4), two-platform serum metabolomics and whole blood gene expression measurements were obtained for 1,631 and 689 participants, respectively. Using weighted correlation network analysis, omics data were clustered into modules of closely connected molecules, followed by the formation of a partial correlation network from the modules. Association of the omics modules with previous annual percentage weight change was then determined using linear models. In addition, we performed pathway enrichment analyses, stability analyses, and assessed the relation of the omics modules with clinical traits.ResultsFour metabolite and two gene expression modules were significantly and stably associated with body weight change (P-values ranging from 1.9 × 10−4 to 1.2 × 10−24). The four metabolite modules covered major branches of metabolism, with VLDL, LDL and large HDL subclasses, triglycerides, branched-chain amino acids and markers of energy metabolism among the main representative molecules. One gene expression module suggests a role of weight change in red blood cell development. The other gene expression module largely overlaps with the lipid-leukocyte (LL) module previously reported to interact with serum metabolites, for which we identify additional co-expressed genes. The omics modules were interrelated and showed cross-sectional associations with clinical traits. Moreover, weight gain and weight loss showed largely opposing associations with the omics modules.ConclusionsLong-term weight change in the general population globally associates with serum metabolite concentrations. An integrated metabolomics and transcriptomics approach improved the understanding of molecular mechanisms underlying the association of weight gain with changes in lipid and amino acid metabolism, insulin sensitivity, mitochondrial function as well as blood cell development and function.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-015-0282-y) contains supplementary material, which is available to authorized users.

Lipoprotein particles and incident type 2 diabetes in the multi-ethnic study of atherosclerosis.

OBJECTIVEIn the Multi-Ethnic Study of Atherosclerosis (MESA), we evaluated associations of baseline levels of a lipoprotein-based insulin resistance (IR) index (LP-IR), IR-related lipoprotein particles, mean particle sizes, and lipids, with incident type 2 diabetes, independent of confounders, glucose, insulin, and HOMA-IR.RESEARCH DESIGN AND METHODSAmong 5,314 adults aged 45–84 years without baseline diabetes or cardiovascular disease, 656 cases of diabetes were identified during a mean follow-up of 7.7 years. Lipoprotein particle concentrations, size, and LP-IR were determined by nuclear magnetic resonance spectroscopy of stored baseline plasma. Potential effect modification, by race/ethnicity, sex, baseline use of lipid-lowering medications or hormone therapy, or glucose strata (<90, 90–99, and ≥100 mg/dL), was also evaluated.RESULTSHigher levels of LP-IR, large VLDL particles (VLDL-P), small LDL particles, triglycerides (TG), and TG–to–HDL cholesterol (HDL-C) ratio and lower levels of large HDL particles, smaller HDL and LDL size, and larger VLDL size were significantly associated with incident diabetes adjusted for confounders and glucose or insulin. These also were similar by race/ethnicity, sex, and treatment group. Associations were similar for LP-IR, large VLDL-P, mean VLDL size, TG, and TG–to–HDL-C ratio; they persisted for LP-IR, large VLDL-P, or mean VLDL size adjusted for HOMA-IR or TG–to–HDL-C ratio and glucose but not for the TG–to–HDL-C ratio adjusted for LP-IR or for HOMA-IR or insulin if adjusted for LP-IR and glucose.CONCLUSIONSAmong ethnically diverse men and women, LP-IR, large VLDL-P, large VLDL size, TG, and TG–to–HDL-C ratio were associated with incident diabetes independent of established risk factors, glucose, insulin, or HOMA-IR, as well as the use of lipid-lowering medications or hormone therapy.

Prevention of fatal hepatic complication in schistosomiasis by inhibition of CETP.

Schistosoma japonicum, once endemic all the East Asia, remains as a serious public health problem in certain regions. Ectopic egg embryonation in the liver causes granulomatosis and eventually fatal cirrhosis, so that prevention of this process is one of the keys to reduce its mortality. The embryonation requires cholesteryl ester from HDL of the host blood for egg yolk formation, and this reaction is impaired from the abnormal large HDL in genetic cholesteryl ester transfer protein (CETP) deficiency. When CETP was expressed in mice that otherwise lack this protein, granulomatosis of the liver was shown increased compared to the wild type upon infection of Schistosoma japonicum. The CETP deficiencies accumulated exclusively in East Asia, from Indochina to Siberia, so that Shistosomiasis can be a screening factor for this accumulation. CD36 related protein (CD36RP) was identified as a protein for this reaction, cloned from the cDNA library of Schistosoma japonicum with 1880-bp encoding 506 amino acids. The antibody against the extracellular loop of CD36RP inhibited cholesteryl ester uptake from HDL and suppressed egg embryonation in culture. Therefore, inhibition of CETP is a potential approach to prevent liver granulomatosis and thereby fatal liver cirrhosis in the infection of Schistosoma japonicum.

Abstract 12252: Effects of the Cholesteryl Ester Transfer Protein Inhibitor, Evacetrapib, Administered as Monotherapy or in Combination With Statins on Cholesterol Efflux and HDL Particles in Patients With Dyslipidemia

Objectives: The CETP inhibitor evacetrapib (EVA) has been shown to substantially increase HDL-C and apoA-I levels as monotherapy and combined with statins. The effects of EVA on cholesterol efflux capacity and HDL particle distribution have not been described and were evaluated in this study. Methods: Samples from patients (n=398) with elevated LDL-C or low HDL-C enrolled in the multicenter, randomized, double-blind, parallel, placebo-controlled trial (JAMA 2011;306:2099-2109, NCT01105975) were studied. Percent changes from baseline in cholesterol efflux capacity (global, ABCA1- and non-ABCA1-mediated), preβ HDL (measured by immunofixation and 2D-gel), and other HDL subclasses (measured by 2D-gel and NMR) were evaluated after 12 weeks of placebo (PBO), statins alone, EVA alone, and EVA with statins. Results: Results are shown in the table. Statins alone decreased global and ABCA1-mediated cholesterol efflux and preβ-1 HDL (by 2D-gel). EVA alone and combined with statins increased global (28% and 21%, respectively), ABCA1- (17% and 15%, respectively), and non-ABCA1-mediated (35% and 27%, respectively) cholesterol efflux. EVA alone increased preβ-1 as measured by 2D-gel (20%) and immunofixation (32%); EVA combined with statins increased preβ-1 as measured by 2D-gel (27%). While statins alone had no significant effect on large and very large HDL (α-1 and α-2 HDL by 2D-gel, and large HDL by NMR), EVA alone and combined with statins increased these more buoyant HDL particles. Statins alone and EVA alone had no effect on small HDL, whereas EVA combined with statins significantly decreased small HDL particles as measured by NMR. Conclusion: In subjects with elevated LDL-C or low HDL-C, EVA alone and combined with statins increased global, ABCA1- and non-ABCA1-mediated cholesterol efflux. This improved global cholesterol efflux capacity was accompanied by a significant increase in preβ-1 and large and very large HDL particles.

Abstract 17913: Inhibition of CETP by Dalcetrapib Results in a Modest Increase in Cholesterol Efflux Capacity Associated With an Increase in Large HDL Particles, but Does Not Impact Carotid Intima-Media Thickness in a dal-PLAQUE-2 Substudy

Inhibition of cholesteryl ester transfer protein (CETP) is an approach aiming at raising HDL-cholesterol levels and reducing cardiovascular risk. The dal-PLAQUE-2 phase III study recruited 988 subjects with stable coronary artery disease. Its primary objective was to evaluate the effect of dalcetrapib on the progression of carotid atherosclerotic disease measured by intima-media thickness after one year of therapy. As dalcetrapib showed a neutral effect on cardiovascular risk in the dal-OUTCOMES study, our objective was to evaluate its effect on cIMT and markers of HDL mass, lipoprotein subclass distribution and HDL function. All subjects from dal-PLAQUE-2 who had provided serum samples at baseline and one year were included in our substudy of 193 subjects on placebo and 186 subjects on dalcetrapib. Comparisons between groups at one year were made by ANCOVA after adjustment for baseline levels. No significant differences between groups for all variables considered were observed at baseline. Dalcetrapib reduced CETP activity as measured by a fluorescent method by 30% after 1 year (p&lt;0.001), which resulted in increases in HDL-cholesterol and apoA-I levels by 32% and 11%, respectively (both p&lt;0.001). Dalcetrapib markedly increased the concentration of large HDL particles measured by NMR profiling (+59%, p&lt;0.001), at the expense of small HDL particles (-9.5%, p&lt;0.001). Cholesterol efflux capacity of serum was measured from J774 macrophages under basal conditions and after cAMP stimulation. Dalcetrapib increased basal and stimulated efflux by 7.1% and 5.5% (both p&lt;0.001), but was without effect on the ABCA1-dependent component (p=0.26). Despite these effects, dalcetrapib had no impact on mean and maximal cIMT (p=0.98 and p=0.85). While the change in cIMT was inversely correlated with basal cholesterol efflux in the placebo group (Spearman r=-0.163, p&lt;0.05), such a relationship was not found in the dalcetrapib group. Moreover, the change in total HDL particles concentration was inversely correlated with change in cIMT (r=0.181, p&lt;0.05) in the placebo arm only. In conclusion, dalcetrapib raised HDL-C and larger HDL, but this had minimal effects on cholesterol efflux capacity of patients’ serum and had a neutral effect on carotid artery plaque burden.

Increased large VLDL and small LDL particles are related to lower bilirubin in Type 2 diabetes mellitus

ObjectivesBilirubin may protect against atherosclerotic cardiovascular disease by virtue of its anti-oxidative properties, but lower bilirubin may also be associated to atherogenic lipoprotein abnormalities. We determined associations of plasma (apo)lipoproteins and lipoprotein subfractions in subjects with and without type 2 diabetes mellitus (T2DM). Design and methodsPlasma (apo)lipoproteins, lipoprotein subfractions (nuclear magnetic resonance spectroscopy) and serum total bilirubin levels were determined in 53 T2DM patients and in 53 non-diabetic subjects. ResultsTriglycerides, large VLDL, small LDL and small HDL particles were increased (all p<0.05), whereas HDL cholesterol, apoA-I and large HDL particles were decreased (all p<0.05), coinciding lower bilirubin levels in T2DM (p<0.001). In age- and sex-adjusted analysis, total cholesterol, non-HDL cholesterol, triglycerides, apoB, apoE, large VLDL and small LDL were negatively correlated with bilirubin, but HDL cholesterol was positively correlated with bilirubin in T2DM (p<0.05 to p<0.001). Multivariable linear regression analyses demonstrated that in all subjects combined total cholesterol, non-HDL cholesterol, triglycerides and apoE were negatively associated with bilirubin after adjustment for age, sex, T2DM, body mass index and alanine aminotransferase (all p<0.05). Further multivariable linear regression analysis showed that large VLDL and small LDL particles were negatively associated with bilirubin, whereas large HDL particles were associated positively with bilirubin (p<0.05). ConclusionsIncreased triglycerides, as well as large VLDL and small LDL particles are associated negatively, whereas HDL cholesterol is associated positively with bilirubin in T2DM. The proposed pro-atherogenic effects of low bilirubin could in part be attributed to relationships with abnormalities in (apo)lipoproteins and lipoprotein subfraction characteristics.

Editorial: current research, knowledge and controversies on high density lipoprotein.

Editorial: current research, knowledge and controversies on high density lipoprotein.

Association of increased large hdl particles with improved cardiopulmonary fitness in acute coronary syndrome patients participated with exercise-based cardiac rehabilitation

Objectives: Exercised-based cardiac rehabilitation (CR) can increase HDL-cholesterol (HDL-C). However it remains unclear how elevated HDL-C and changes of HDL subfractions are correlated with the improvement of exercise tolerance in acute coronary syndrome (ACS) patients participated with CR.

Circulating irisin, omentin-1, and lipoprotein subparticles in adults at higher cardiovascular risk

ObjectiveMuscle and fat are now recognized as metabolism-regulating endocrine organs. However, muscle and adipocyte-derived novel cytokines such as irisin and omentin-1 remain understudied in relation to metabolic biomarkers that are associated with cardiovascular risk. Subjects and methodsThirty-nine subjects with mean (±SD) BMI of 29.2±5.4kg/m2 and either diabetes or two other cardiovascular risk factors were enrolled in a 6-month randomized trial of low-dose ethanol. We examined cross-sectional data at baseline, 3-month, and 6-month visits to assess (1) within-person stability of novel cytokines (irisin, omentin-1, visfatin, resistin, and soluble tumor necrosis factor receptor II) and (2) their associations with metabolic parameters, particularly lipoprotein subparticle profile. ResultsRepeated measures of irisin and omentin-1 were highly correlated, with intra-class correlations of 0.84 (95% CI: 0.74, 0.91; P<0.001) and 0.81 (0.70, 0.89; P<0.001), respectively. Irisin was negatively correlated with omentin-1 (7.4% irisin decrease per a 1-SD increment in omentin-1; 95% CI: 0.5%, 13.9%; P=0.04). In models adjusted for age, sex, and race, irisin was negatively associated with HDL cholesterol (7.3% decrease per a 10mg/dL increment; 1.0%, 13.3%; P=0.02) and large HDL particles (15.5% decrease per a 1-SD or 3.5-μmol/L increment; 5.2%, 24.7%; P=0.005). Omentin-1 was positively associated with mean VLDL size (3.8% increase per a 1-SD increment; 0.06%, 7.8%; P=0.05). Adjustment for alcohol intervention, BMI, and other cytokines did not materially affect these associations. ConclusionsIrisin and omentin-1 are stable within-person, inversely associated with each other, and closely related to lipoprotein profile. These molecules may be promising markers for cardiovascular risk.

Abstract 630: Lipoprotein Subclasses by Ion Mobility and First Cardiovascular Events: An Analysis of 11,227 Participants From the JUPITER Trial

Background: Ion mobility (IM) measures lipoprotein subclasses based on physically separating particles by their size. It is uncertain how IM lipoproteins compare with standard lipids and apolipoproteins in predicting CVD, and whether they relate to residual risk after statin therapy. Methods: JUPITER recruited participants based on LDL-C &lt;130 mg/dL and hsCRP ≥2 mg/L. In 11,227 participants, baseline and on-treatment lipoproteins were measured by IM, and lipids and apolipoproteins were chemically assayed before and after randomization to rosuvastatin or placebo. Levels were examined with the primary trial endpoint of first CVD (n=309) and an expanded endpoint of CVD/all-cause death (n=524). Results: In placebo-allocated participants, baseline LDL-C was not associated with CVD (risk-factor adjusted hazard ratio [HR] per 1-SD, 1.04, 95% CI 0.90-1.20), in contrast to significant associations for baseline non-HDL-C, apoB, and IM-measured non-HDL particles (non-HDL-P), LDL particles (LDL-P) and most LDL subclasses. Significant associations were also noted for baseline triglycerides, medium and large VLDL, and HDL-C, but not IM IDL or HDL subclasses. In addition, IM measures a region (size range between very small LDL and large HDL) with two fractions that were significantly associated with CVD: Mid-Zone 1 (190-180 Angstrom) and Mid-Zone 2 (180-145 Angstrom). In separate models that adjusted for risk factors plus standard lipids, significant associations were noted for apoB (adjusted HR per 1-SD 1.26, 1.02-1.56), non-HDL-P (1.19, 1.03-1.39), LDL-P (1.18, 1.03-1.36), Mid-Zones 1 (1.20, 1.04-1.38) and 2 (1.15, 1.04-1.28), several LDL subclasses, and small IDL. In statin-allocated participants, risk of CVD was associated with on-treatment LDL-C, non-HDL-C, and apoB but not on-treatment IM lipoproteins although some, such as Mid-Zone 2, were related to risk of CVD/all-cause death. Conclusion: In placebo-allocated JUPITER participants, LDL particle-based measures were more strongly related to CVD than LDL-C, while in statin-allocated participants, residual risk was related to on-treatment LDL-C, non-HDL-C and apoB. Furthermore, this is the first study to identify two novel fractions that signified increased risk and warrant future investigation.

Abstract 9: Metabolic Pathways for HDL Subtypes in Low-HDL Overweight Phenotype Compared With Normal

Introduction: A prevailing concept of HDL metabolism in plasma is that HDL is secreted into plasma as a small discoidal particle; and then expands and contracts by uptake and removal of cholesterol. This process has not been studied directly in humans. Hypothesis: We hypothesized that the 4 common sizes of HDL will show interconversions suggesting reverse cholesterol transport and that is impaired in those who have low HDL-c levels. Methods: We studied 12 adults, ages 30 to 70; six had low HDL-c (mean 39 mg/dL) and were overweight, and 6 had high HDL-c (mean 79 mg/dL) and normal body weight. They received a intravenous bolus of trideuterated leucine with serial blood sampling for 94 hours. HDL sizes, very small (&lt;7.1 nm), small (7.1-8.2 nm), medium (8.2-9.5 nm) and large (9.5-12.2), were separated, and the isotope enrichments and masses of apoA-I in each HDL size were measured by mass spectrometry. We tested many kinetic models using SAAM-II. Results: In both HDL groups, we found similar peak enrichment heights and times in the four HDL sizes suggesting mostly independent metabolism which was confirmed by the final model that had excellent fits to the data. Most of each plasma HDL size subfraction originated from direct secretion into plasma. Only small amounts of apoA-I flux went from smaller to larger HDL, 19% in the low vs 2% in the high HDL group (p=0.006); and in the opposite direction, 3% in the low vs 9% in the high HDL group (ns). ApoA-I in medium and large HDL had faster fractional catabolic rates (FCRs) in the low than in the high HDL group (0.61 vs 0.31 pools/day [p=0.004] and 0.51 vs 0.24 pools/day [p=0.01]), respectively). In contrast, apoA-I in very small (prebeta) HDL had slower FCR in the low than high HDL group (0.51 vs 0.73/d [p=0.048]). Secretion rates of apoA-I into plasma HDL of each size were not significantly different between the groups. Total apoA-I secretion was 12 vs 14 mg/kg/d in the low vs high HDL group (ns). Conclusions: Our results question the concepts of reverse cholesterol transport dominating plasma HDL metabolism, and of its impairment in those with low plasma HDL-c levels. Differences in apoA-I FCR of HDL subfractions explained the well-known shift in size distribution toward smaller HDL in those who have low HDL-c.

Abstract 238: Incubation of MDCO216 With Human Serum or Plasma Potentiates ABCA1-Mediated Cholesterol Efflux Capacity, Increases Prebeta-1 HDL and Causes a Shift From Small to Large Alpha HDL Particles

MDCO216 is a complex of dimeric apoA-IMilano and POPC, shown to reduce atherosclerotic plaque burden. Here we studied the effect of incubation of human plasma or serum with MDCO216 on cholesterol efflux capacity from J774 cells, on prebeta-1 HDL and various HDL subfractions. At clinically relevant concentrations MDCO216 by itself markedly stimulates global and ABCA1-mediated cholesterol efflux. When incubated with human serum a time-dependent synergistic increase of the ABCA1 mediated efflux capacity is observed. Using the Sekisui ELISA for prebeta-1 HDL, MDCO216 itself is poorly detected. Prebeta-1 HDL is rapidly lost when human plasma alone is incubated at 37 o C. However, incubation of human plasma with MDCO216 at 37 o C causes a robust generation of new prebeta-1 HDL. 2D-Electrophoresis followed by immunoblotting with a general apoA-I antibody that also detects apoA-IM confirms the increase in prebeta-1 HDL (having a different mobility than pure MDCO216 particles), and shows a concomitant disappearance of alpha-3 HDL, alpha-4 HDL and MDCO216, and an increase in alpha-1 and alpha-2 HDL. NMR analysis of plasma incubated with MDCO216 at 47 o C confirms very rapid disappearance of small HDL and increase of medium and large HDL particles. In conclusion, incubation of human plasma or serum with MDCO216 strongly enhances ABCA1-mediated cholesterol efflux capacity, causes a strong increase of prebeta-1 HDL and drastically changes HDL subfraction distribution, consistent with anti-atherosclerotic activity.

Abstract 235: Atorvastatin Has No Impact on the Effects of CETP Inhibitors on HDL Structure and Cholesterol Efflux Capacity in Chow-Fed Rabbits

Introduction: In the dal-OUTCOMES trial, cholesteryl ester transfer protein (CETP) inhibition by dalcetrapib increased HDL-C but had a neutral effect on CV risk. However, these patients were also treated with standard-of-care therapies including statins, a drug class shown to reduce ABCA1 mRNA expression in human peripheral blood mononuclear cells (PBMC). Hypothesis: Given the role of ABCA1 in cholesterol efflux and HDL biogenesis, we determined the impact of atorvastatin on the potential beneficial effects provided by dalcetrapib and anacetrapib, two CETP inhibitors. Methods: Dalcetrapib (300 mg/kg) or anacetrapib (30 mg/kg) were administered to New Zealand White rabbits receiving or not atorvastatin (2.5 mg/kg) for 14 days. Lipid profiles were measured biochemically. ApoA-I distribution in HDL subclasses was evaluated by 1D-non-denaturing gradient gel electrophoresis (1D-NDGGE). BHK cells with inducible expression of human ABCA1 and HepG2 hepatocytes were used to measure ABCA1- and SR-BI-dépendent cholesterol efflux. Human THP-1 macrophages and PBMC isolated from rabbits were also used for efflux assays. Results: Dalcetrapib increased HDL-C by +81% (p&lt;0.01) and total apoA-I (1D-NDGGE) by 1.5-fold (p&lt;0.01). This was associated with an increase in both large and small α-migrating HDL (+52%, p&lt;0.05; +74%, p&lt;0.05). Cholesterol efflux showed that ABCA1- and SR-BI-dependent effluxes to apoB-depleted serum were increased in dalcetrapib-treated rabbits (+31%, p&lt;0.01; +38%, p&lt;0.001). Atorvastatin had no impact on all these parameters. Moreover, treatment of THP-1 with atorvastatin did not inhibit the increase of cholesterol efflux (+24%, p&lt;0.01) induced by depleted serum from dalcetrapib-treated rabbits. Efflux capacity of PBMC isolated from rabbits treated with atorvastatin was also unchanged compared to the other groups. The absence of effect of atorvastatin on cholesterol efflux was also observed with anacetrapib. Conclusion: CETP inhibition increased HDL-C, apoA-I levels and cholesterol efflux from different cell types. Atorvastatin had no effect on these parameters, suggesting that the increased cholesterol efflux capacity induced by CETPi is not hampered by statins.