The Effect of Diet on Cardiovascular Disease, Heart Disease, and Blood Vessels.

The Effect of Diet on Cardiovascular Disease, Heart Disease, and Blood Vessels [...].

Association between Monocyte to High-Density Lipoprotein Cholesterol Ratio and Nonalcoholic Fatty Liver Disease: A Cross-Sectional Study.

BACKGROUND: The aim of the present study was to investigate the association between monocyte to high-density lipoprotein cholesterol ratio (MHR) and nonalcoholic fatty liver disease (NAFLD) in Chinese population. METHODS: We enrolled 14189 individuals who attended their annual health examinations in the study. We performed the anthropometric and laboratory measurements and diagnosed NAFLD by hepatic ultrasonography without evidence of other etiologies of chronic liver disease. Student's t-test, Mann-Whitney U test, and chi-squared (χ 2) test was used to compare the differences of clinical characteristics between participants with or without NAFLD. Pearson's and Spearman's analyses were performed to assess the correlation of MHR and NAFLD risk factors. Univariate and multivariate logistic regression analyses were conducted to explore whether MHR associated with NAFLD. RESULTS: Thirty-five percent of the participants enrolled were diagnosed with NAFLD. Compared with healthy controls, NAFLD patients were male predominant, older, and had higher body mass index, waist circumference, and systolic and diastolic blood pressure, as well as higher levels of alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, triglyceride, total cholesterol, low-density lipoprotein cholesterol, fasting plasma glucose, glycated hemoglobin A1c, and serum uric acid, but lower levels of serum high-density lipoprotein cholesterol. Besides, MHR was significantly higher in NAFLD patients than healthy controls [5.35 (4.18-6.84) versus 4.53 (3.48-5.93), P < 0.001]. MHR quartiles were positively related to the prevalence of NAFLD (P < 0.001 for trend). In multivariate logistic regression analysis, MHR was positively associated with the risk of NAFLD after adjusting age, gender, body mass index, waist circumference, diastolic blood pressure, alanine aminotransferase, triglyceride, total cholesterol, fasting plasma glucose, and serum uric acid (OR: 1.026, 95% CI: 1.002-1.052; P = 0.037). CONCLUSIONS: MHR is significantly and positively associated with the risk of NAFLD.

Matcha Green Tea Powder does not Prevent Diet-Induced Arteriosclerosis in New Zealand White Rabbits Due to Impaired Reverse Cholesterol Transport.

INTRODUCTION: Green tea is associated with decreased risk for cardiovascular disease and stroke. Matcha is a special kind of powdered green tea known for its use in the Japanese tea ceremony. Due to its influence on lipoprotein parameters, it has been postulated to exert antiatherogenic effects. This study investigates whether it modulates the high-density lipoprotein (HDL) function and thereby influences the atherogenic process in an animal model with a strong influence on humans' situation. METHODS AND RESULTS: After a pretreatment phase based on a standard diet, 10 female New Zealand White (NZW) rabbits are fed a high-fat diet for 20 weeks. The treatment group is additionally administered 1% matcha during the whole experiment. Long-term matcha treatment leads to lowered HDL cholesterol, impaired cholesterol transport manifested by reduced in vitro cholesterol efflux capacity, reduced cholesteryl ester transfer protein (CETP)-mediated cholesterol ester (CE) transfer between HDL and triglyceride-rich particles, and reduced macrophage-specific in vivo transfer, where ian increased absorption of cholesterol in the liver but a decreased secretion into bile is observed. Pulse wave velocity, assessed by nuclear magnetic resonance, is increased in matcha-treated animals, and a similar trend is observed for atherosclerotic lesion formation. CONCLUSION: Long-term matcha green tea treatment of hypercholesterolemic rabbits cause impaired reverse cholesterol transport and increased vascular stiffness, and susceptibility for atherosclerotic lesion development.

HDL Cholesterol and Non-Cardiovascular Disease: A Narrative Review.

High density lipoprotein (HDL) cholesterol has traditionally been considered the "good cholesterol", and most of the research regarding HDL cholesterol has for decades revolved around the possible role of HDL in atherosclerosis and its therapeutic potential within atherosclerotic cardiovascular disease. Randomized trials aiming at increasing HDL cholesterol have, however, failed and left questions to what role HDL cholesterol plays in human health and disease. Recent observational studies involving non-cardiovascular diseases have shown that high levels of HDL cholesterol are not necessarily associated with beneficial outcomes as observed for age-related macular degeneration, type II diabetes, dementia, infection, and mortality. In this narrative review, we discuss these interesting associations between HDL cholesterol and non-cardiovascular diseases, covering observational studies, human genetics, and plausible mechanisms.

Direct Estimation of HDL-Mediated Cholesterol Efflux Capacity from Serum.

BACKGROUND: HDL-mediated cholesterol efflux capacity (HDL-CEC) is a functional attribute that may have a protective role in atherogenesis. However, the estimation of HDL-CEC is based on in vitro cell assays that are laborious and hamper large-scale phenotyping. METHODS: Here, we present a cost-effective high-throughput nuclear magnetic resonance (NMR) spectroscopy method to estimate HDL-CEC directly from serum. We applied the new method in a population-based study of 7603 individuals including 574 who developed incident coronary heart disease (CHD) during 15 years of follow-up, making this the largest quantitative study for HDL-CEC. RESULTS: As estimated by NMR-spectroscopy, a 1-SD higher HDL-CEC was associated with a lower risk of incident CHD (hazards ratio, 0.86; 95%CI, 0.79-0.93, adjusted for traditional risk factors and HDL-C). These findings are consistent with published associations based on in vitro cell assays. CONCLUSIONS: These corroborative large-scale findings provide further support for a potential protective role of HDL-CEC in CHD and substantiate this new method and its future applications.

High-Density Lipoprotein Function Is Reduced in Patients Affected by Genetic or Idiopathic Hypogonadism.

CONTEXT: Low testosterone levels are associated with an increased incidence of cardiovascular (CV) events, but the underlying biochemical mechanisms are not fully understood. The clinical condition of hypogonadism offers a unique model to unravel the possible role of lipoprotein-associated abnormalities in CV risk. In particular, the assessment of the functional capacities of high-density lipoproteins (HDLs) may provide insights besides traditional risk factors. DESIGN: To determine whether reduced testosterone levels correlate with lipoprotein function, HDL cholesterol (HDL-C) efflux capacity (CEC) and serum cholesterol loading capacity (CLC). PARTICIPANTS: Genetic and idiopathic hypogonadal patients (n = 20) and control subjects (n = 17). RESULTS: Primary and secondary hypogonadal patients presented with lower HDL ATP-binding cassette transporter A1 (ABCA1)-, ATP-binding cassette transporter G1 (ABCG1)-, and aqueous diffusion-mediated CEC (-19.6%, -40.9%, and -12.9%, respectively), with a 16.2% decrement of total CEC. In the whole series, positive correlations between testosterone levels and both total HDL CEC (r2 = 0.359, P = 0.0001) and ABCG1 HDL CEC (r2 = 0.367, P = 0.0001) were observed. Conversely, serum CLC was markedly raised (+43%) in hypogonadals, increased, to a higher extent, in primary vs secondary hypogonadism (18.45 ± 2.78 vs 15.15 ± 2.10 µg cholesterol/mg protein) and inversely correlated with testosterone levels (r2 = 0.270, P = 0.001). HDL-C concentrations did not correlate with either testosterone levels, HDL CEC (total, ABCG1, and ABCA1) or serum CLC. CONCLUSIONS: In hypogonadal patients, proatherogenic lipoprotein-associated changes are associated with lower cholesterol efflux and increased influx, thus offering an explanation for a potentially increased CV risk.

Cholesterol Mass Efflux Capacity, Incident Cardiovascular Disease, and Progression of Carotid Plaque.

Objective- To assess the role of HDL (high-density lipoprotein)-mediated cholesterol mass efflux capacity (CMEC) in incident cardiovascular disease and carotid plaque progression. Approach and Results- We measured CMEC in 2 cohorts aged 45 to 84 years at baseline derived from the MESA (Multi-Ethnic Study of Atherosclerosis). Cohort 1 comprised 465 cases with incident cardiovascular disease events during 10 years of follow-up and 465 age- and sex-matched controls; cohort 2 comprised 407 cases with progression of carotid plaque measured by ultrasonography at 2 exams >10 years and 407 similarly matched controls. Covariates and outcome events were ascertained according to the MESA protocol. CMEC level was modestly correlated with HDL cholesterol ( R=0.13; P<0.001) but was not associated with age, sex, race/ethnicity, body mass index, diabetes mellitus, alcohol use, smoking status, or statin use. Higher CMEC level was significantly associated with lower odds of cardiovascular disease (odds ratio, 0.82 per SD of CMEC [95% CI, 0.69-0.98; P=0.031] in the fully adjusted model) in cohort 1 but higher odds of carotid plaque progression (odds ratio, 1.24 per SD of CMEC [95% CI, 1.04-1.48; P=0.018] in the fully adjusted model) in cohort 2 but without dose-response effect. In subgroup analysis within cohort 1, higher CMEC was associated with lower risk of incident coronary heart disease events (odds ratio, 0.72 per SD of CMEC (95% CI, 0.5-0.91; P=0.007) while no association was found with stroke events. Conclusions- These findings support a role for HDL-mediated cholesterol efflux in an atheroprotective mechanism for coronary heart disease but not stroke.

Association of a cholesteryl ester transfer protein variant (rs1800777) with fat mass, HDL cholesterol levels, and metabolic syndrome / Asociación de la variante (rs1800777) de proteína de transferencia de ésteres de colesterol con masa grasa, niveles de colesterol HDL y síndrome metabólico

Background: There is little evidence of the association between CETP SNPs and obesity and/or related metabolic parameters. Objective: To analyze the association of the polymorphism rs1800777 of the CETP gene with anthropometric parameters, lipid profile, metabolic syndrome and its components, and adipokine levels in obese subjects without type 2 diabetes mellitus or hypertension. Design: A population of 1005 obese subjects was analyzed. Electrical bioimpedance was performed, and blood pressure, presence of metabolic syndrome, dietary intake, physical activity, and biochemical tests were recorded. Results: Nine hundred and sixty eight patients (96.3%) had the GG genotype, 37 patients the GA genotype (3.7%) (no AA genotype was detected). Fat mass (delta: 4.4±1.1kg; p=0.04), waist circumference (delta: 5.6±2.1cm; p=0.02), and waist to hip ratio (delta: 0.04±0.01cm; p=0.01) were higher in A allele carriers than in non-A allele carriers. HDL cholesterol levels were lower in A allele carriers than in non-A allele carriers (delta: 4.2±1.0mg/dL; p=0.04). In the logistic regression analysis, the GA genotype was associated to an increased risk of central obesity (OR 7.55, 95% CI 1.10-55.70, p=0.02) and low HDL cholesterol levels (OR 2.46, 95% CI 1.23-4.91, p=0.014). Conclusion: The CETP variant at position +82 is associated to lower HDL cholesterol levels, increased fat mass, and central obesity in obese subjects. These results may suggest a potential role of this variant gene in pathophysiology of adipose tissue

Antecedentes: Existen pocas evidencias en relación a la asociación entre los SNP de CETP y la presencia de obesidad y/o parámetros metabólicos relacionados. Objetivo: Examinar la asociación del polimorfismo (rs1800777) del gen CETP con parámetros antropométricos, perfil lipídico, presencia de síndrome metabólico y sus diferentes componentes y los niveles de adipocitoquinas en sujetos con obesidad sin diabetes mellitus ni hipertensión. Diseño: Se analizó una población de 1.005 sujetos con obesidad. Se registró una bioimpedancia, presión arterial, presencia de síndrome metabólico, ingesta dietética, ejercicio físico y parámetros bioquímicos. Resultados: Novecientos sesenta y ocho pacientes (96,3%) tuvieron el genotipo GG y 37 pacientes presentaron el genotipo GA (3,7%) (no se detectó genotipo AA). La masa grasa (delta: 4,4±1,1kg; p=0,04), circunferencia de la cintura (delta: 5,6±2,1cm; p=0,02), relación cintura-cadera (delta: 0,04±0,01cm; p=0,01) fueron mayores en los portadores del alelo A. El colesterol HDL fue menor en los portadores del alelo A (delta: 4,2±1,0mg/dl; p=0,04). En el análisis de regresión logística la presencia del alelo A se asoció con un mayor riesgo de obesidad central (OR: 7,55; IC 95%: 1,10-55,70; p=0,02) y un mayor riesgo de colesterol HDL bajo (OR: 2,46; IC 95%: 1,23-4,91; p=0,014). Conclusión: La variante CETP en la posición +82 se asocia a unos niveles más bajos de colesterol HDL, a un mayor porcentaje de masa grasa y obesidad central en personas con obesidad. Estos resultados podrían sugerir un posible papel de esta variante en la fisiopatología del tejido adiposo

Cardiovascular Benefits of Phenol-Enriched Virgin Olive Oils: New Insights from the Virgin Olive Oil and HDL Functionality (VOHF) Study.

SCOPE: The main findings of the "Virgin Olive Oil and HDL Functionality" (VOHF) study and other related studies on the effect of phenol-enriched virgin olive oil (VOO) supplementation on cardiovascular disease are integrated in the present work. METHODS AND RESULTS: VOHF assessed whether VOOs, enriched with their own phenolic compounds (FVOO) or with those from thyme (FVOOT), improve quantity and functionality of HDL. In this randomized, double-blind, crossover, and controlled trial, 33 hypercholesterolemic subjects received a control VOO (80 mg kg-1 ), FVOO (500 mg kg-1 ), and FVOOT (500 mg kg-1 ; 1:1) for 3 weeks. Both functional VOOs promoted cardioprotective changes, modulating HDL proteome, increasing fat-soluble antioxidants, improving HDL subclasses distribution, reducing the lipoprotein insulin resistance index, increasing endogenous antioxidant enzymes, protecting DNA from oxidation, ameliorating endothelial function, and increasing fecal microbial metabolic activity. Additional cardioprotective benefits were observed according to phenol source and content in the phenol-enriched VOOs. These insights support the beneficial effects of OO and PC from different sources. CONCLUSION: Novel therapeutic strategies should increase HDL-cholesterol levels and enhance HDL functionality. The tailoring of phenol-enriched VOOs is an interesting and useful strategy for enhancing the functional quality of HDL, and thus, it can be used as a complementary tool for the management of hypercholesterolemic individuals.

Novel association between CDKAL1 and cholesterol efflux capacity: Replication after GWAS-based discovery.

BACKGROUND AND AIMS: Although the importance of the functional properties of high-density lipoprotein (HDL) has been increasingly emphasized, studies on the genetic factors associated with HDL function are highly limited. The aim of this study was to identify genetic variants associated with an individual's cholesterol efflux capacity (CEC) using a genome-wide association study approach. METHODS: This study included a discovery group of 607 subjects with coronary artery disease and an independent replication group of 158 subjects. CEC was assessed using a radioisotope and ApoB-depleted serum. Genome-wide associations between the adjusted CEC and genotyped and imputed variants were examined with linear regression, assuming an additive genetic model. Finally, adjustments were made for confounding parameters to assess the independence of associations and to determine R2 of overall model on CEC. RESULTS: In the discovery group, 631 variants showed significant association with CEC, and five of them were found to correlate with CEC in the replication group. One of them was located near LOC541471 in 2q13, whereas the other four (rs117835232, rs117252933, rs118064592, and rs150434350) were located in CDKAL1 in 6p22.3. The association between the presence of any CDKAL1 variant and CEC was significant after adjustment for clinical and laboratory variables. High-density lipoprotein-cholesterol levels also showed a very significant association with CEC. Body mass index, current alcohol use, triglycerides levels, low-density lipoprotein-cholesterol levels and statin use showed borderline associations with CEC. CONCLUSIONS: We identified and replicated genetic variants associated with CEC using a genome-wide association study-based approach. CDKAL1 variants showed correlations with CEC independent of HDL-cholesterol levels and other clinical characteristics.

Extreme high high-density lipoprotein cholesterol is paradoxically associated with high mortality in men and women: two prospective cohort studies.

AIMS: High-density lipoprotein (HDL) cholesterol concentrations are inversely associated with cardiovascular disease and mortality across a range of concentrations, but genetic evidence suggest that extreme high concentrations may paradoxically lead to more cardiovascular disease. We tested the hypothesis that extreme high concentrations of HDL cholesterol are associated with high all-cause mortality in men and women. METHODS AND RESULTS: A total of 52 268 men and 64 240 women were included from the two prospective population-based studies, the Copenhagen City Heart Study and the Copenhagen General Population Study. During 745 452 person-years of follow-up, number of deaths from any cause were 5619 (mortality rate, 17.1/1000 person-years (95% confidence interval (CI): 16.7-17.6)) in men and 5059 (mortality rate, 12.1/1000 person-years (11.8-12.4)) in women. The association between HDL cholesterol concentrations and all-cause mortality was U-shaped for both men and women, with both extreme high and low concentrations being associated with high all-cause mortality risk. The concentration of HDL cholesterol associated with the lowest all-cause mortality was 1.9 mmol/L (95% CI: 1.4-2.0) (73 mg/dL (54-77)) in men and 2.4 mmol/L (1.8-2.5) (93 mg/dL (69-97)) in women. When compared with the groups with the lowest risk, the multifactorially adjusted hazard ratios for all-cause mortality were 1.36 (95% CI: 1.09-1.70) for men with HDL cholesterol of 2.5-2.99 mmol/L (97-115 mg/dL) and 2.06 (1.44-2.95) for men with HDL cholesterol ≥3.0 mmol/L (116 mg/dL). For women, corresponding hazard ratios were 1.10 (0.83-1.46) for HDL cholesterol of 3.0-3.49 mmol/L (116-134 mg/dL) and 1.68 (1.09-2.58) for HDL cholesterol ≥3.5 mmol/L (135 mg/dL). CONCLUSION: Men and women in the general population with extreme high HDL cholesterol paradoxically have high all-cause mortality. These findings need confirmation in other studies.

Intake of up to 3 Eggs per Day Is Associated with Changes in HDL Function and Increased Plasma Antioxidants in Healthy, Young Adults.

Background: HDL function may be more important than HDL concentration in determining risk for cardiovascular disease. In addition, HDL is a carrier of carotenoids and antioxidant enzymes, which protect HDL and LDL particles against oxidation.Objective: The goal of this study was to determine the impact of consuming 0-3 eggs/d on LDL and HDL particle size, HDL function, and plasma antioxidants in a young, healthy population.Methods: Thirty-eight healthy men and women [age 18-30 y, body mass index (in kg/m2) 18.5-29.9] participated in this 14-wk crossover intervention. Subjects underwent a 2-wk washout (0 eggs/d) followed by sequentially increasing intake of 1, 2, and 3 eggs/d for 4 wk each. After each period, fasting blood was collected for analysis of lipoprotein subfractions, plasma apolipoprotein (apo) concentration, lutein and zeaxanthin concentration, and activities of lecithin-cholesterol acyltransferase, cholesteryl ester transfer protein, and paraoxonase-1.Results: Compared with intake of 0 eggs/d, consuming 1-3 eggs/d resulted in increased large-LDL (21-37%) and large-HDL (6-13%) particle concentrations, plasma apoAI (9-15%), and lecithin-cholesterol acyltransferase activity (5-15%) (P < 0.05 for all biomarkers). Intake of 2-3 eggs/d also promoted an 11% increase in apoAII (P < 0.05) and a 20-31% increase in plasma lutein and zeaxanthin (P < 0.05), whereas intake of 3 eggs/d resulted in a 9-16% increase in serum paraoxonase-1 activity compared with intake of 1-2 eggs/d (P < 0.05). Egg intake did not affect cholesteryl ester transfer protein activity.Conclusions: Intake of 1 egg/d was sufficient to increase HDL function and large-LDL particle concentration; however, intake of 2-3 eggs/d supported greater improvements in HDL function as well as increased plasma carotenoids. Overall, intake of ≤3 eggs/d favored a less atherogenic LDL particle profile, improved HDL function, and increased plasma antioxidants in young, healthy adults. This trial was registered at clinicaltrials.gov as NCT02531958.

Impaired antioxidant HDL function is associated with premature myocardial infarction.

BACKGROUND: There is growing evidence that the predictive value of HDL cholesterol levels for cardiovascular risk stratification is limited in patients with coronary artery disease (CAD). HDL function seems to be a more sensitive surrogate of cardiovascular risk estimation than simple serum levels. Therefore, we aimed to assess whether impaired antioxidant HDL function is involved in the development of premature acute myocardial infarction (AMI). METHODS: In this multicentre case-control study, we compared the antioxidant function of HDL, measured by the HDL inflammatory index (HII), and HDL particle size in 184 patients comprising 92 patients with AMI at a very young age (≤40 years of age) and 92 age- and gender-matched controls. RESULTS: Antioxidant capacities of HDL were significantly impaired in the acute phase of AMI (HII of 1·50 [IQR 1·10-1·74] vs. 0·56 [IQR 0·41-0·86] in controls, P < 0·001 as well as in the chronic stable phase 1 year after the event (HII of 0·85 [IQR 0·72-1·03] vs. 0·56 [IQR 0·41-0·86], P < 0·001) compared to controls. Moreover, HDL function in the stable phase remained significantly associated with premature MI in adjusted logistic regression analysis with an OR of 2·24 per SD increase of HII (95% CI 1·28-3·91; P = 0·005). Analyses of HDL size revealed a significant correlation between all HDL subfractions and HDL function in controls, whereas this correlation was lost for large and intermediate HDL in AMI patients. CONCLUSION: Impaired antioxidant function of HDL is independently associated with the development of premature AMI. The maintenance of HDL function might evolve into a significant therapeutic target, especially in patients with premature CAD.

Anacetrapib reduces progression of atherosclerosis, mainly by reducing non-HDL-cholesterol, improves lesion stability and adds to the beneficial effects of atorvastatin.

BACKGROUND: The residual risk that remains after statin treatment supports the addition of other LDL-C-lowering agents and has stimulated the search for secondary treatment targets. Epidemiological studies propose HDL-C as a possible candidate. Cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from atheroprotective HDL to atherogenic (V)LDL. The CETP inhibitor anacetrapib decreases (V)LDL-C by ∼15-40% and increases HDL-C by ∼40-140% in clinical trials. We evaluated the effects of a broad dose range of anacetrapib on atherosclerosis and HDL function, and examined possible additive/synergistic effects of anacetrapib on top of atorvastatin in APOE*3Leiden.CETP mice. METHODS AND RESULTS: Mice were fed a diet without or with ascending dosages of anacetrapib (0.03; 0.3; 3; 30 mg/kg/day), atorvastatin (2.4 mg/kg/day) alone or in combination with anacetrapib (0.3 mg/kg/day) for 21 weeks. Anacetrapib dose-dependently reduced CETP activity (-59 to -100%, P < 0.001), thereby decreasing non-HDL-C (-24 to -45%, P < 0.001) and increasing HDL-C (+30 to +86%, P < 0.001). Anacetrapib dose-dependently reduced the atherosclerotic lesion area (-41 to -92%, P < 0.01) and severity, increased plaque stability index and added to the effects of atorvastatin by further decreasing lesion size (-95%, P < 0.001) and severity. Analysis of covariance showed that both anacetrapib (P < 0.05) and non-HDL-C (P < 0.001), but not HDL-C (P = 0.76), independently determined lesion size. CONCLUSION: Anacetrapib dose-dependently reduces atherosclerosis, and adds to the anti-atherogenic effects of atorvastatin, which is mainly ascribed to a reduction in non-HDL-C. In addition, anacetrapib improves lesion stability.

HDL cholesterol subclasses, myocardial infarction, and mortality in secondary prevention: the Lipoprotein Investigators Collaborative.

AIMS: High-density lipoprotein (HDL) is highly heterogeneous and the link of its subclasses to prognosis remains controversial. We aimed to rigorously examine the associations of HDL subclasses with prognosis in secondary prevention. METHODS AND RESULTS: We collaboratively analysed data from two, complementary prospective cohorts: the TRIUMPH study of 2465 acute myocardial infarction patients, and the IHCS study of 2414 patients who underwent coronary angiography. All patients had baseline HDL subclassification by vertical-spin density gradient ultracentrifugation. Given non-linearity, we stratified by tertiles of HDL-C and its two major subclasses (HDL2-C, HDL3-C), then compared multivariable-adjusted hazard ratios for mortality and mortality/myocardial infarction. Patients were middle-aged to elderly (TRIUMPH: 58.2 ± 12.2 years; IHCS: 62.6 ± 12.6 years), and the majority were men (TRIUMPH: 68.0%; IHCS: 65.5%). IHCS had lower mean HDL-C levels (34.6 ± 10.1 mg/dL) compared with TRIUMPH (40 ± 10.6 mg/dL). HDL3-C accounted for >3/4 of HDL-C (mean HDL3-C/HDL-C 0.78 ± 0.05 in both cohorts). During 2 years of follow-up in TRIUMPH, 226 (9.2%) deaths occurred, while death/myocardial infarction occurred in 401 (16.6%) IHCS patients over 5 years. No independent associations with outcomes were observed for HDL-C or HDL2-C. In contrast, the lowest tertile of HDL3-C was independently associated with >50% higher risk in each cohort (TRIUMPH: with middle tertile as reference, fully adjusted HR for mortality of HDL3-C, 1.57; 95% CI, 1.13-2.18; IHCS: fully adjusted HR for mortality/myocardial infarction, 1.55; 95% CI, 1.20-2.00). CONCLUSION: In secondary prevention, increased risk for long-term hard clinical events is associated with low HDL3-C, but not HDL2-C or HDL-C, highlighting the potential value of subclassifying HDL-C.

Role of HDL in those with diabetes.

Low levels of high-density lipoprotein cholesterol (HDL-C) have been associated with an increased risk of coronary heart disease in prospective population studies and clinical trials of high-risk patients treated with a low to moderate intensity statin. As a result, therapeutic targets were developed to increase concentrations of HDL-C. Subsequently, clinical trials of high-intensity statins have not supported this previously well-established association. In trials of high-intensity statin therapy, low HDL particle concentration (HDL-P) has been associated with an increased risk of future cardiovascular events. Therefore, strategies that increase HDL-C without expanding the pool of HDL-P with its rich proteome/lipidome do not seem to be an effective strategy. In this review, we discuss potential mechanisms of action for the anti-atherogenic effect of HDL and the impact of current and emerging therapies on the functional capacity of HDL-P. Finally, we discuss emerging therapies that increase the concentration and functional properties of HDL.

Mendelian randomization studies in coronary artery disease.

Epidemiological research over the last 50 years has discovered a plethora of biomarkers (including molecules, traits or other diseases) that associate with coronary artery disease (CAD) risk. Even the strongest association detected in such observational research precludes drawing conclusions about the causality underlying the relationship between biomarker and disease. Mendelian randomization (MR) studies can shed light on the causality of associations, i.e whether, on the one hand, the biomarker contributes to the development of disease or, on the other hand, the observed association is confounded by unrecognized exogenous factors or due to reverse causation, i.e. due to the fact that prevalent disease affects the level of the biomarker. However, conclusions from a MR study are based on a number of important assumptions. A prerequisite for such studies is that the genetic variant employed affects significantly the biomarker under investigation but has no effect on other phenotypes that might confound the association between the biomarker and disease. If this biomarker is a true causal risk factor for CAD, genotypes of the variant should associate with CAD risk in the direction predicted by the association of the biomarker with CAD. Given a random distribution of exogenous factors in individuals carrying respective genotypes, groups represented by the genotypes are highly similar except for the biomarker of interest. Thus, the genetic variant converts into an unconfounded surrogate of the respective biomarker. This scenario is nicely exemplified for LDL cholesterol. Almost every genotype found to increase LDL cholesterol level by a sufficient amount has also been found to increase CAD risk. Pending a number of conditions that needed to be fulfilled by the genetic variant under investigation (e.g. no pleiotropic effects) and the experimental set-up of the study, LDL cholesterol can be assumed to act as the functional component that links genotypes and CAD risk and, more importantly, it can be assumed that any modulation of LDL cholesterol-by whatever mechanism-would have similar effects on disease risk. Therefore, MR analysis has tremendous potential for identifying therapeutic targets that are likely to be causal for CAD. This review article discusses the opportunities and challenges of MR studies for CAD, highlighting several examples that involved multiple biomarkers, including various lipid and inflammation traits as well as hypertension, diabetes mellitus, and obesity.

Should low high-density lipoprotein cholesterol (HDL-C) be treated?

The first observations linking a low serum level of HDL-C to increased risk for cardiovascular disease were made over 50 years ago. High serum levels of HDL-C appear to protect against the development of atherosclerotic disease, while low serum levels of this lipoprotein are among the most important predictors of atherosclerotic disease in both men and women and people of all racial and ethnic groups throughout the world. It has long been assumed that therapeutic interventions targeted at raising HDL-C levels would lower risk for such cardiovascular events as myocardial infarction, ischemic stroke, and death. Even after five decades of intensive investigation, evidence to support this assumption has been fleeting. A number of post hoc analyses of randomized controlled trials and meta-analyses suggest that HDL-C raising, particularly when coupled with aggressive LDL-C reduction, impacts risk for cardiovascular events and rates of progression of atherosclerotic disease. Unfortunately, four recent prospective trials performed with the intent of testing the "HDL hypothesis" (ILLUMINATE, dal-OUTCOMES, AIM-HIGH, and HPS2-THRIVE) failed to meet their primary composite endpoints. These results have lead many clinicians and investigators to question the validity of the assumption that HDL-C raising reduces risk for cardiovascular events. Additional trials with other drugs are underway. In the meantime, HDL-C cannot be considered a target of therapy. Given the complexity of the HDL proteome and lipidome, there is biological plausibility for how HDL particles might exert atheroprotection. We explore the evidence supporting the inverse relationship between HDL-C and cardiovascular disease risk, documented mechanisms by which HDL particles may exert atheroprotection, and the findings either supporting or negating specific therapeutic interventions in patients afflicted with low HDL-C.

Emerging therapies for raising high-density lipoprotein cholesterol (HDL-C) and augmenting HDL particle functionality.

High-density lipoprotein (HDL) particles are highly complex polymolecular aggregates capable of performing a remarkable range of atheroprotective functions. Considerable research is being performed throughout the world to develop novel pharmacologic approaches to: (1) promote apoprotein A-I and HDL particle biosynthesis; (2) augment capacity for reverse cholesterol transport so as to reduce risk for the development and progression of atherosclerotic disease; and (3) modulate the functionality of HDL particles in order to increase their capacity to antagonize oxidation, inflammation, thrombosis, endothelial dysfunction, insulin resistance, and other processes that participate in arterial wall injury. HDL metabolism and the molecular constitution of HDL particles are highly complex and can change in response to both acute and chronic alterations in the metabolic milieu. To date, some of these interventions have been shown to positively impact rates of coronary artery disease progression. However, none of them have as yet been shown to significantly reduce risk for cardiovascular events. In the next 3-5 years a variety of pharmacologic interventions for modulating HDL metabolism and functionality will be tested in large, randomized, prospective outcomes trials. It is hoped that one or more of these therapeutic approaches will result in the ability to further reduce risk for cardiovascular events once low-density lipoprotein cholesterol and non-HDL-cholesterol targets have been attained.