Relationships between HDL subpopulation proteome and HDL function in overweight/obese people with and without coronary heart disease.

BACKGROUND AND AIMS: The structure-function relationships of high-density lipoprotein (HDL) subpopulations are not well understood. Our aim was to examine the interrelationships between HDL particle proteome and HDL functionality in subjects with and without coronary heart disease (CHD). METHODS: We isolated 5 different HDL subpopulations based on charge, size, and apolipoprotein A1 (APOA1) content from the plasma of 33 overweight/obese CHD patients and 33 age-and body mass index (BMI)-matched CHD-free subjects. We measured the relative molar concentration of HDL-associated proteins by liquid chromatography tandem mass spectrometry (LC-MS/MS) and assessed particle functionality. RESULTS: We quantified 110 proteins associated with the 5 APOA1-containing HDL subpopulations. The relative molar concentration of these proteins spanned five orders of magnitude. Only 10 proteins were present in >1% while 73 were present in <0.1% concentration. Only 6 of the 10 most abundant proteins were apolipoproteins. Interestingly, the largest (α-1) and the smallest (preß-1) HDL particles contained the most diverse proteomes. The protein composition of each HDL subpopulation was altered in CHD cases as compared to controls with the most prominent differences in preß-1 and α-1 particles. APOA2 concentration was positively correlated with preß-1 particle functionality (ABCA1-CEC/mg APOA1 in preß-1) (R2 = 0.42, p = 0.005), while APOE concentration was inversely correlated with large-HDL particle functionality (SRBI-CEC/mg APOA1 in α-1+α-2) (R2 = 0.18, p = 0.01). CONCLUSIONS: The protein composition of the different HDL subpopulations was altered differentially in CHD patients. The functionality of the small and large HDL particles correlated with the protein content of APOA2 and APOE, respectively. Our data indicate that distinct particle subspecies and specific particle associated proteins provide new information about the role of HDL in CHD.

Ethyl EPA and ethyl DHA cause similar and differential changes in plasma lipid concentrations and lipid metabolism in subjects with low-grade chronic inflammation.

BACKGROUND: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to similarly lower plasma TG concentrations but differentially regulate plasma LDL-C and HDL-C concentrations. OBJECTIVE: The aim of this study was to evaluate the common and differential effects of these ω-3 fatty acids on plasma lipids and lipoproteins and to assess the metabolic mechanisms of the effects. METHODS: In a randomized, double-blind, crossover study, we assessed the effect of 10-week supplementation with 3 g/d pure EPA and pure DHA (both as ethyl ester, ≥97% purity) on plasma lipid and lipoprotein concentrations and activities of lipoprotein lipase (LPL), cholesteryl ester transfer protein (CETP) and lecithin:cholesterol acyl transferase (LCAT) in 21 older (>50 y) men and postmenopausal women with some characteristics of metabolic syndrome and low-grade chronic inflammation. RESULTS: Both EPA and DHA lowered plasma TG concentrations and increased LDL-C/apoB and HDL-C/apoA-I ratios, but only DHA increased LDL-C concentrations. The reductions in plasma TG were inversely associated with the changes in LPL activity after both EPA and DHA supplementation. EPA lowered CETP, while DHA lowered LCAT activity. EPA and DHA worked differently in men and women, with DHA increasing LPL activity and LDL-C concentrations in women, but not in men. CONCLUSIONS: EPA and DHA exerted similar effects on plasma TG, but differences were observed in LDL-C concentrations and activities of some enzymes involved in lipoprotein metabolism. It was also noted that EPA and DHA worked differently in men and women, supporting sex-specific variations in lipoprotein metabolism.

The role of HDL- and non-HDL-related parameters in cell-cholesterol efflux capacity.

BACKGROUND AND AIMS: The regulation of cell-cholesterol efflux is not completely understood. Our aim was to assess the role of HDL- and non-HDL-related parameters in ATP-binding cassette transporter-A1 (ABCA1) and scavenger receptor class B-type-I (SRBI) cell-cholesterol efflux capacity (CEC) in coronary heart disease (CHD) cases and controls. METHODS: Lipids and apoA-I-containing HDL particles (by 2D gel-electrophoresis and immunodetection) were measured in 534 statin-treated CHD patients and in 1076 age-, gender-, and BMI-matched controls. ABCA1-CEC and SRBI-CEC were measured in apoB-depleted serum of 100 cases and 100 controls. RESULTS: Cases had significantly higher concentrations of preß-1 particles (88%) and ABCA1-CEC (34%) compared to controls. ABCA1-CEC was positively correlated with the concentrations of preß-1 particles, triglycerides, small-dense (sd) LDL-C, and LDL-C in both cases and controls. Moreover, both the concentration and the functionality of preß-1 particles (ABCA1-CEC/mg preß-1) were positively associated with the concentrations of sdLDL-C and triglycerides. Cases had 27% lower levels of large HDL particles but similar SRBI-CEC compared to controls. SRBI-CEC was correlated positively with HDL-C, apoA-I, and large-HDL particle levels. However, the functionality of large-HDL particles (SRBI-CEC/mg large particles) was significantly and positively correlated with the preß-1/α-1 ratio, sdLDL-C, and triglycerides. CONCLUSIONS: CHD patients have significantly higher concentration, but less functional preß-1 particles in term of cholesterol efflux capacity compared to controls. Triglyceride-rich lipoproteins have significant influence on either the concentration or the functionality or both of HDL particles and consequently HDL-CEC.

Small Dense Low-Density Lipoprotein Cholesterol Is the Most Atherogenic Lipoprotein Parameter in the Prospective Framingham Offspring Study.

Background Elevated plasma levels of direct low-density lipoprotein cholesterol (LDL-C), small dense LDL-C (sdLDL-C), low-density lipoprotein (LDL) triglycerides, triglycerides, triglyceride-rich lipoprotein cholesterol, remnant lipoprotein particle cholesterol, and lipoprotein(a) have all been associated with incident atherosclerotic cardiovascular disease (ASCVD). Our goal was to assess which parameters were most strongly associated with ASCVD risk. Methods and Results Plasma total cholesterol, triglycerides, high-density lipoprotein cholesterol, direct LDL-C, sdLDL-C, LDL triglycerides, remnant lipoprotein particle cholesterol, triglyceride-rich lipoprotein cholesterol, and lipoprotein(a) were measured using standardized automated analysis (coefficients of variation, <5.0%) in samples from 3094 fasting subjects free of ASCVD. Of these subjects, 20.2% developed ASCVD over 16 years. On univariate analysis, all ASCVD risk factors were significantly associated with incident ASCVD, as well as the following specialized lipoprotein parameters: sdLDL-C, LDL triglycerides, triglycerides, triglyceride-rich lipoprotein cholesterol, remnant lipoprotein particle cholesterol, and direct LDL-C. Only sdLDL-C, direct LDL-C, and lipoprotein(a) were significant on multivariate analysis and net reclassification after adjustment for standard risk factors (age, sex, hypertension, diabetes mellitus, smoking, total cholesterol, and high-density lipoprotein cholesterol). Using the pooled cohort equation, many specialized lipoprotein parameters individually added significant information, but no parameter added significant information once sdLDL-C (hazard ratio, 1.42; P<0.0001) was in the model. These results for sdLDL-C were confirmed by adjusted discordance analysis versus calculated non-high-density lipoprotein cholesterol, in contrast to LDL triglycerides. Conclusions sdLDL-C, direct LDL-C, and lipoprotein(a) all contributed significantly to ASCVD risk on multivariate analysis, but no parameter added significant risk information to the pooled cohort equation once sdLDL-C was in the model. Our data indicate that small dense LDL is the most atherogenic lipoprotein parameter.

Small Dense Low-Density Lipoprotein Cholesterol and Carotid Intimal Medial Thickness Progression.

AIM: The association between small dense low-density lipoprotein cholesterol (sdLDL-C) levels and carotid intimal medial thickness (cIMT) progression has not been evaluated fully. We assessed specialized lipoproteins, including sdLDL-C, with regard to cIMT progression in a prospective observational study in Japan. METHODS: Plasma total cholesterol, direct LDL-C, sdLDL-C, LDL-triglycerides (LDL-TG), high-density lipoprotein cholesterol (HDL-C), HDL2-C, HDL3-C, triglycerides, Lp(a), and adiponectin were measured in 2,030 men and women (median age 59 years, free of cardiovascular disease (CVD) and off cholesterol lowering medication). At both baseline and after a five-year follow-up, cIMT was assessed. Univariate, multivariate regression, and least square analyses were performed to examine the relationships between direct LDL-C, sdLDL-C, and other lipoproteins with cIMT progression. RESULTS: The median cIMT at baseline was 0.63 mm and five-year progression was 0.18 mm. After adjustment for standard CVD risk factors, including age, gender, systolic blood pressure, total cholesterol, HDL-C, smoking, diabetes, and hypertension treatment, only direct LDL-C, sdLDL-C, and the sdLDL-C/LDL-C ratio were associated with cIMT progression. Even in subjects with direct LDL-C ＜100 mg/dL, who were considered at low CVD risk, elevated sdLDL-C were associated with cIMT progression (P for trend=0.009) in a model with established CVD risk factors, although the sdLDL-C/LDL-C ratio did not. Those correlations did not change by including triglycerides as a controlling factor or excluding premenopausal women from the analyzed population. CONCLUSIONS: Small dense LDL-C has a stronger relationship with cIMT progression than LDL-C does; therefore, measuring sdLDL-C may allow for the formulation of optimal therapy for CVD prevention.

Composition-function analysis of HDL subpopulations: influence of lipid composition on particle functionality.

The composition-function relationship of HDL particles and its effects on the mechanisms driving coronary heart disease (CHD) is poorly understood. We tested the hypothesis that the functionality of HDL particles is significantly influenced by their lipid composition. Using a novel 3D-separation method, we isolated five different-sized HDL subpopulations from CHD patients who had low preß-1 functionality (low-F) (ABCA1-dependent cholesterol-efflux normalized for preß-1 concentration) and controls who had either low-F or high preß-1 functionality (high-F). Molecular numbers of apoA-I, apoA-II, and eight major lipid classes were determined in each subpopulation by LC-MS. The average number of lipid molecules decreased from 422 in the large spherical α-1 particles to 57 in the small discoid preß-1 particles. With decreasing particle size, the relative concentration of free cholesterol (FC) decreased in α-mobility but not in preß-1 particles. Preß-1 particles contained more lipids than predicted; 30% of which were neutral lipids (cholesteryl ester and triglyceride), indicating that these particles were mainly remodeled from larger particles not newly synthesized. There were significant correlations between HDL-particle functionality and the concentrations of several lipids. Unexpectedly, the phospholipid:FC ratio was significantly correlated with large-HDL-particle functionality but not with preß-1 functionality. There was significant positive correlation between particle functionality and total lipids in high-F controls, indicating that the lipid-binding capacity of apoA-I plays a major role in the cholesterol efflux capacity of HDL particles. Functionality and lipid composition of HDL particles are significantly correlated and probably both are influenced by the lipid-binding capacity of apoA-I.

Proceedings of the Ninth HDL (High-Density Lipoprotein) Workshop: Focus on Cardiovascular Disease.

The HDL (high-density lipoprotein) Workshop was established in 2009 as a forum for candid discussions among academic basic scientists, clinical investigators, and industry researchers about the role of HDL in cardiovascular disease. This ninth HDL Workshop was held on May 16 to 17, 2019 in Boston, MA, and included outstanding oral presentations from established and emerging investigators. The Workshop featured 5 sessions with topics that tackled the role of HDL in the vasculature, its structural complexity, its role in health and disease states, and its interaction with the intestinal microbiome. The highlight of the program was awarding the Jack Oram Award to the distinguished professor emeritus G.S. Getz from the University of Chicago. The tenth HDL Workshop will be held on May 2020 in Chicago and will continue the focus on intellectually stimulating presentations by established and emerging investigators on novel roles of HDL in cardiovascular and noncardiovascular health and disease states.

Direct Versus Calculated LDL Cholesterol and C-Reactive Protein in Cardiovascular Disease Risk Assessment in the Framingham Offspring Study.

BACKGROUND: Increases in circulating LDL cholesterol (LDL-C) and high-sensitivity C-reactive protein (hsCRP) concentrations are significant risk factors for cardiovascular disease (CVD). We assessed direct LDL-C and hsCRP concentrations compared to standard risk factors in the Framingham Offspring Study. METHODS: We used stored frozen plasma samples (-80 °C) obtained after an overnight fast from 3147 male and female participants (mean age, 58 years) free of CVD at cycle 6 of the Framingham Offspring Study. Overall, 677 participants (21.5%) had a CVD end point over a median of 16.0 years of follow-up. Total cholesterol (TC), triglyceride (TG), HDL cholesterol (HDL-C), direct LDL-C (Denka Seiken and Kyowa Medex methods), and hsCRP (Dade Behring method) concentrations were measured by automated analysis. LDL-C was also calculated by both the Friedewald and Martin methods. RESULTS: Considering all CVD outcomes on univariate analysis, significant factors included standard risk factors (age, hypertension, HDL-C, hypertension treatment, sex, diabetes, smoking, and TC concentration) and nonstandard risk factors (non-HDL-C, direct LDL-C and calculated LDL-C, TG, and hsCRP concentrations). On multivariate analysis, only the Denka Seiken direct LDL-C and the Dade Behring hsCRP were still significant on Cox regression analysis and improved the net risk reclassification index, but with modest effects. Discordance analysis confirmed the benefit of the Denka Seiken direct LDL-C method for prospective hard CVD endpoints (new-onset myocardial infarction, stroke, and/or CVD death). CONCLUSIONS: Our data indicate that the Denka Seiken direct LDL-C and Dade Behring hsCRP measurements add significant, but modest, information about CVD risk, compared to standard risk factors and/or calculated LDL-C.

High-density lipoprotein: our elusive friend.

PURPOSE OF REVIEW: Despite advances in the research on HDL composition (lipidomics and proteomics) and functions (cholesterol efflux and antioxidative capacities), the relationship between HDL compositional and functional properties is not fully understood. We have reviewed the recent literature on this topic and pointed out the difficulties which limit our understanding of HDL's role in cardiovascular disease (CVD). RECENT FINDINGS: Though current findings strongly support that HDL has a significant role in CVD, the underlying mechanisms by which HDL mitigates CVD risk are not clear. This review focuses on studies that investigate the cell-cholesterol efflux capacity and the proteomic and lipidomic characterization of HDL and its subfractions especially those that analyzed the relationship between HDL composition and functions. SUMMARY: Recent studies on HDL composition and HDL functions have greatly contributed to our understanding of HDL's role in CVD. A major problem in HDL research is the lack of standardization of both the HDL isolation and HDL functionality methods. Data generated by different methods often produce discordant results on the particle number, size, lipid and protein composition, and the various functions of HDL.

Effects of weight change on HDL-cholesterol and its subfractions in over 28,000 men and women.

BACKGROUND: Changes in body mass index (ΔBMI) have well-established relationships to changes in high-density lipoprotein (ΔHDL)-cholesterol concentrations; however, their relationships to ΔHDL subfractions are less well understood. OBJECTIVE: Assess the associations between ΔHDL and ΔBMI in a very large cohort. METHOD: Age and sex-adjusted Δapo A1 concentrations were measured within 10 HDL subfractions in 14,121 women and 13,969 men using two-dimensional HDL-mapping. Significance was identified at .01 < P ≤ .05 (*), .001 < P ≤ .01 (†), .0001 < P ≤ .001 (‡), and P ≤ .0001 (§). RESULTS: ΔBMI was significantly associated with Δα-1 (very large HDL, slope ± SE, females: -0.39 ± 0.07§; males: -0.51 ± 0.05§), Δα-3 (medium HDL, females: 0.18 ± 0.04§; males: 0.19 ± 0.04§), and Δα-4 (small HDL, females: 0.14 ± 0.03§; males: 0.15 ± 0.04§ mg/dL per kg/m2). As a percent of baseline, the changes in α-1 per ΔBMI were nearly twice as great as the changes in HDL-cholesterol per ΔBMI in both males (-1.53% vs -0.77%) and females (-0.79% vs -0.42%). HDL-cholesterol decreased significantly in healthy-weight patients who became overweight, overweight patients who became class I or class II obese, class I obese patients who became class II obese, and class II obese patients who became class III. In contrast, HDL-cholesterol increased in class III obese patients who became class II or class I, class II obese patients who became class I or overweight, class I patients who became overweight or healthy weight, overweight patients who became healthy weight, and healthy weight patients who became underweight. CONCLUSIONS: Weight change significantly affects HDL-cholesterol concentrations throughout the obesity spectrum. ΔBMI's effect on Δα-1 was nearly twice as great as its effect on HDL-cholesterol.

Genetic and secondary causes of severe HDL deficiency and cardiovascular disease.

We assessed secondary and genetic causes of severe HDL deficiency in 258,252 subjects, of whom 370 men (0.33%) and 144 women (0.099%) had HDL cholesterol levels <20 mg/dl. We excluded 206 subjects (40.1%) with significant elevations of triglycerides, C-reactive protein, glycosylated hemoglobin, myeloperoxidase, or liver enzymes and men receiving testosterone. We sequenced 23 lipid-related genes in 201 (65.3%) of 308 eligible subjects. Mutations (23 novel) and selected variants were found at the following gene loci: 1) ABCA1 (26.9%): 2 homozygotes, 7 compound or double heterozygotes, 30 heterozygotes, and 2 homozygotes and 13 heterozygotes with variants rs9282541/p.R230C or rs111292742/c.-279C>G; 2) LCAT (12.4%): 1 homozygote, 3 compound heterozygotes, 13 heterozygotes, and 8 heterozygotes with variant rs4986970/p.S232T; 3) APOA1 (5.0%): 1 homozygote and 9 heterozygotes; and 4) LPL (4.5%): 1 heterozygote and 8 heterozygotes with variant rs268/p.N318S. In addition, 4.5% had other mutations, and 46.8% had no mutations. Atherosclerotic cardiovascular disease (ASCVD) prevalence rates in the ABCA1, LCAT, APOA1, LPL, and mutation-negative groups were 37.0%, 4.0%, 40.0%, 11.1%, and 6.4%, respectively. Severe HDL deficiency is uncommon, with 40.1% having secondary causes and 48.8% of the subjects sequenced having ABCA1, LCAT, APOA1, or LPL mutations or variants, with the highest ASCVD prevalence rates being observed in the ABCA1 and APOA1 groups.

High-Density Lipoprotein Particles, Cell-Cholesterol Efflux, and Coronary Heart Disease Risk.

Objective- The cell-cholesterol efflux capacity of HDL (high-density lipoprotein) is inversely associated with coronary heart disease risk. ABCA1 (ATP-binding cassette transporter A1) plays a crucial role in cholesterol efflux from macrophages to preß-1-HDL. We tested the hypothesis that coronary heart disease patients have functionally abnormal preß-1-HDL. Approach and Results- HDL cell-cholesterol efflux capacity via the ABCA1 and the SR-BI (scavenger receptor class B type I) pathways, HDL antioxidative capacity, apo (apolipoprotein) A-I-containing HDL particles, and inflammatory- and oxidative-stress markers were measured in a case-control study of 100 coronary heart disease cases and 100 sex-matched controls. There were significant positive correlations between ABCA1-dependent cholesterol efflux and the levels of small lipid-poor preß-1 particles ( R2=0.535) and between SR-BI-dependent cholesterol efflux and the levels of large lipid-rich (α-1+α-2) HDL particles ( R2=0.712). Cases had significantly higher (87%) preß-1 concentrations than controls, but the functionality of their preß-1 particles (preß-1 concentration normalized ABCA1-dependent efflux capacity) was significantly lower (-31%). Cases had significantly lower (-12%) mean concentration of large HDL particles, but the functionality of their particles (α-1+α-2 concentration normalized SR-BI-dependent efflux capacity) was significantly higher (22%) compared with that of controls. HDL antioxidative capacity was significantly lower (-16%) in cases than in controls. There were no significant correlations between either preß-1 functionality or large HDL particle functionality with HDL antioxidative capacity or the concentrations of inflammatory- and oxidative-stress markers. Conclusions- HDL cell-cholesterol efflux capacity is significantly influenced by both the concentration and the functionality of specific HDL particles participating in cell-cholesterol efflux. Coronary heart disease patients have higher than normal preß-1 concentrations with decreased functionality and lower than normal large HDL particle concentrations with enhanced functionality.

Where next with HDL assays?

PURPOSE OF REVIEW: The inverse association between HDL cholesterol (HDL-C) and cardiovascular disease (CVD) has been unequivocally proven in the past several decades. However, some interventions aiming to increase HDL-C failed to reduce CVD risk. HDL is structurally and functionally complex and HDL-associated metrics other than HDL-C, such as the concentration, composition, and functionality of HDL particles, have been considered as better determinants of CVD risk. A large body of recent research has addressed changes in HDL functions and HDL subpopulations in CVD with the goal of discovering novel and reliable biomarkers and targets for the treatment or prevention of CVD. RECENT FINDINGS: We have reviewed recent findings on HDL composition, HDL particle concentrations, and cell-cholesterol efflux capacity that have lately contributed to our understanding of HDL's role in CVD. SUMMARY: We point out that a major problem in HDL research is the lack of standardization of HDL assays that has led to discrepancies among studies. Therefore, there is a need for new standardized assays that capture the complexities of key HDL parameters.

Saturated Fats from Butter but Not from Cheese Increase HDL-Mediated Cholesterol Efflux Capacity from J774 Macrophages in Men and Women with Abdominal Obesity.

Background: Recent evidence suggests that the association between dietary saturated fatty acids (SFAs) and coronary artery disease risk varies according to food sources. How SFAs from butter and cheese influence HDL-mediated cholesterol efflux capacity (CEC), a key process in reverse cholesterol transport, is currently unknown. Objective: In a predefined secondary analysis of a previously published trial, we have examined how diets rich in SFAs from either cheese or butter influence HDL-mediated CEC, compared with diets rich in either monounsaturated fatty acids (MUFAs) or polyunsaturated fatty acids (PUFAs). Methods: In a randomized crossover controlled consumption trial, 46 men and women with abdominal obesity consumed 5 isocaloric diets, each for 4 wk. Two diets were rich in SFAs either from cheese (CHEESE) or butter (BUTTER) [12.4-12.6% of energy (%E) as SFAs, 32%E as fat, 52%E as carbohydrates]. In 2 other diets, SFAs (5.8%E) were replaced with either MUFAs from refined olive oil (MUFA) or PUFAs from corn oil (PUFA). Finally, a lower fat and carbohydrate diet was used as a control (5.8%E as SFAs, 25.0%E as fat, 59%E as carbohydrates; CHO). Post-diet HDL-mediated CEC was determined ex vivo using radiolabelled J774 macrophages incubated with apolipoprotein B-depleted serum from the participants. Results: Mean (±SD) age was 41.4 ± 14.2 y, and waist circumference was 107.6 ± 11.5 cm in men and 94.3 ± 12.4 cm in women. BUTTER and MUFA increased HDL-mediated CEC compared with CHEESE (+4.3%, P = 0.026 and +4.7%, P = 0.031, respectively). Exploring the significant diet × sex interaction (P = 0.044) revealed that the increase in HDL-mediated CEC after BUTTER compared with CHEESE was significant among men (+6.0%, P = 0.047) but not women (+2.9%, P = 0.19), whereas the increase after MUFA compared with CHEESE was significant among women (+9.1%, P = 0.008) but not men (-0.6%, P = 0.99). Conclusion: These results provide evidence of a food matrix effect modulating the impact of dairy SFAs on HDL-mediated CEC with potential sex-related differences that deserve further investigation. This trial was registered at clinicaltrials.gov as NCT02106208.

HDL Particle Measurement: Comparison of 5 Methods.

BACKGROUND: HDL cell cholesterol efflux capacity has been documented as superior to HDL cholesterol (HDL-C) in predicting cardiovascular disease risk. HDL functions relate to its composition. Compositional assays are easier to perform and standardize than functional tests and are more practical for routine testing. Our goal was to compare measurements of HDL particles by 5 different separation methods. METHODS: HDL subfractions were measured in 98 samples using vertical auto profiling (VAP), ion mobility (IM), nuclear magnetic resonance (NMR), native 2-dimensional gel electrophoresis (2D-PAGE), and pre-ß1-ELISA. VAP measured cholesterol in large HDL2 and small HDL3; IM measured particle number directly in large, intermediate, and small HDL particles; NMR measured lipid signals in large, medium, and small HDL; 2D-PAGE measured apolipoprotein (apo) A-I in large (α1), medium (α2), small (α3-4), and pre-ß1 HDL particles; and ELISA measured apoA-I in pre-ß1-HDL. The data were normalized and compared using Passing-Bablok, Lin concordance, and Bland-Altman plot analyses. RESULTS: With decreasing HDL-C concentration, NMR measured a gradually lower percentage of large HDL, compared with IM, VAP, and 2D-PAGE. In the lowest HDL-C tertile, NMR measured 8% of large HDL, compared with IM, 22%; VAP, 20%; and 2D-PAGE, 18%. There was strong discordance between 2D-PAGE and NMR in measuring medium HDL (R2 = 0.356; rc = 0.042) and small HDL (R2 = 0.376; rc = 0.040). The 2D-PAGE assay measured a significantly higher apoA-I concentration in pre-ß1-HDL than the pre-ß1-ELISA (9.8 vs 1.6 mg/dL; R2 = 0.246; rc = 0.130). CONCLUSIONS: NMR agreed poorly with the other methods in measuring large HDL, particularly in low HDL-C individuals. Similarly, there was strong discordance in pre-ß1-HDL measurements between the ELISA and 2D-PAGE assays.

HDL subclasses and the common CETP TaqIB variant predict the incidence of microangiopatic complications in type 2 diabetic women: A 9years follow-up study.

AIMS: Diabetic kidney disease (DKD) and retinopathy (DR) develop in a considerable number of subjects with Type 2 Diabetes (T2D) despite the achievement of the recommended targets for glycaemia and blood pressure. Atherogenic dyslipidemia may play a relevant role, especially in T2DM women. METHODS: We report our findings on the effect of diabetic dyslipidaemia, the HDL subclasses distribution and the common cholesteryl ester transfer protein (CETP)TaqIB variant on the incidence or the progression of DKD and DR in 97 T2D women, after a ∼9years of follow-up. RESULTS: At baseline, T2D women presented with low HDL-C levels and higher levels of large lipid rich α-1 (16.34mg/dl), α-2 (33.39mg/dl) and pre- α1 (4.81mg/dl) HDL subparticles. The CETP TaqIB polymorphism and baseline HbA1c, triglycerides, and HDL-C levels as well as specific HDL subpopulations were associated to the occurrence of RD after ∼9years of follow-up. At stepwise regression analysis, HbA1c, triglycerides and the less atheroprotective α-3 HDL particles were the only factors independently associated to the incidence of RD. These same variables were also associated with the progression from background to proliferative RD. BMI, LDL/HDL ratio and low levels of α-1 HDL particles were associated to the occurrence of DKD at univariate analysis, although BMI was the only significant predictor at stepwise multivariate regression analysis. CONCLUSIONS: In T2D women, atherogenic dyslipidemia as well as subtle modifications in lipoprotein particles profile are associated with incidence and progression of microvascular disease.

Cardiovascular disease prevalence and insulin resistance in the Kyushu-Okinawa Population Study and the Framingham Offspring Study.

BACKGROUND: Age-adjusted cardiovascular disease (CVD) prevalence rates are significantly lower in Japan than in the United States. OBJECTIVE: Our aim was to compare CVD risk in participants in Fukuoka and Framingham. METHODS: We measured glucose, insulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), small dense LDL-C, and triglycerides in men and women from Fukuoka (n = 1108), and age (median, 53 years) and gender-matched subjects from Framingham (n = 1101). Blood pressure, body mass index, use of medications, and history of CVD were also assessed. RESULTS: CVD prevalence rates were more than 6-fold higher in Framingham men and women than their Fukuoka counterparts (P < .001). Median body mass index, LDL-C, insulin levels, and insulin resistance assessment in Fukuoka men and women were significantly (P < .01) lower than in Framingham; however, diabetes prevalence in Fukuoka men was significantly (P < .01) higher than in Framingham men, whereas female rates were similar, as were levels of systolic blood pressure. High-density lipoprotein cholesterol and surprisingly small dense LDL-C levels were significantly (P < .001) higher in Fukuoka than in Framingham. Standard risk factors do not account for the large differences in CVD prevalence rates between the 2 populations, and population differences in insulin resistance may explain some of these differences. CONCLUSIONS: Our data are consistent with the concept that the CVD prevalence rate in a Japanese population is much lower than those observed in the United States, and that these differences cannot be explained by standard CVD risk factors, but may relate to marked population differences in insulin resistance.

Influence of HDL particles on cell-cholesterol efflux under various pathological conditions.

It has been reported that low cell-cholesterol efflux capacity (CEC) of HDL is an independent risk factor for CVD. To better understand CEC regulation, we measured ABCA1- and scavenger receptor class B type I (SR-BI)-dependent cell-cholesterol efflux, HDL anti-oxidative capacity, HDL particles, lipids, and inflammatory- and oxidative-stress markers in 122 subjects with elevated plasma levels of triglyceride (TG), serum amyloid A (SAA), fibrinogen, myeloperoxidase (MPO), or ß-sitosterol and in 146 controls. In controls, there were strong positive correlations between ABCA1-dependent cholesterol efflux and small preß-1 concentrations (R2 = 0.317) and SR-BI-dependent cholesterol efflux and large (α-1 + α-2) HDL particle concentrations (R2 = 0.774). In high-TG patients, both the concentration and the functionality (preß-1 concentration-normalized ABCA1 efflux) of preß-1 particles were significantly elevated compared with controls; however, though the concentration of large particles was significantly decreased, their functionality (large HDL concentration-normalized SR-BI efflux) was significantly elevated. High levels of SAA or MPO were not associated with decreased functionality of either the small (preß-1) or the large (α-1 + α-2) HDL particles. HDL anti-oxidative capacity was negatively influenced by high plasma ß-sitosterol levels, but not by the concentrations of HDL particles, TG, SAA, fibrinogen, or MPO. Our data demonstrate that under certain conditions CEC is influenced not only by quantitative (concentration), but also by qualitative (functional) properties of HDL particles.

Ethnic Differences in Glucose Homeostasis Markers between the Kyushu-Okinawa Population Study and the Framingham Offspring Study.

We compared markers of glucose homeostasis and their association with diabetes and impaired fasting glucose (IFG) in Fukuoka, Japanese subjects (n = 1108) and age-, gender- and menopausal status-matched participants in the Framingham Offspring Study (n = 1096). The markers examined included fasting glucose, insulin, adiponectin, and glycated albumin, as well as body mass index (BMI), use of medications, and history of diabetes. The results showed that IFG prevalence in Japanese men (15.9%) and women (7.4%) were 50% less than those observed in Framingham men (34.5%) and women (21.4%) (P < 0.001). However, the diabetes prevalence in Japanese men at 13.3% was twice as high (P < 0.01) as the rate in Framingham men at 6.5%, while these rates were similar in women. Median insulin levels in Japanese men (4.6 µIU/mL) and women (4.3 µIU/mL) were about 50% lower (P < 0.001) than those in Framingham men (10.8 µIU/mL) and women (9.9 µIU/mL), as were insulin resistance values (P < 0.001). These population differences were also observed after subjects were stratified by glucose levels. In conclusion, our data indicate that there is significantly less IFG, lower insulin levels, and insulin resistance, but higher diabetes prevalence in Fukuoka men than in Framingham men, indicating that insulin deficiency may be an important cause of diabetes in Japan.

Effects of eicosapentaenoic acid and docosahexaenoic acid on cardiovascular disease risk factors: a randomized clinical trial.

BACKGROUND: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the primary omega-3 fatty acids in fish oil, have been shown to reduce cardiovascular disease (CVD) risk. OBJECTIVE: This study aimed to examine the independent effects of EPA and DHA on lipid and apolipoprotein levels, as well as on inflammatory biomarkers of CVD risk, using doses often used in the general population. DESIGN: A blinded, randomized 6-week trial was performed in 121 healthy, normolipidemic subjects who received olive oil placebo 6g/d, EPA 600mg/d, EPA 1800mg/d, or DHA 600mg/d. The EPA was derived from genetically modified yeast. RESULTS: The subjects tolerated the supplements well with no safety issues; and the expected treatment-specific increases in plasma EPA and DHA levels were observed. Compared to placebo, the DHA group had significant decreases in postprandial triglyceride (TG) concentrations (-20%, -52.2mg/dL, P=0.03), significant increases in fasting and postprandial low-density lipoprotein cholesterol (LDL-C) (+18.4%, 17.1mg/dL, P=0.001), with no significant changes in inflammatory biomarkers. No significant effects were observed in the EPA 600mg/d group. The high-dose EPA group had significant decreases in lipoprotein-associated phospholipase A2 concentrations (Lp-PLA2) (-14.1%, -21.4ng/mL, P=0.003). CONCLUSIONS: The beneficial effects of EPA 1800mg/d on CVD risk reduction may relate in part to the lowering of Lp-PLA2 without adversely affecting LDL-C. In contrast, DHA decreased postprandial TG, but raised LDL-C. Our observations indicate that these dietary fatty acids have divergent effects on cardiovascular risk markers.