Small High-density Lipoprotein Subclass Research Articles

Proteomic and functional analysis of HDL subclasses in humans and rats: a proof-of-concept study

BackgroundThe previous study investigated whether the functions of small, medium, and large high density lipoprotein (S/M/L-HDL) are correlated with protein changes in mice. Herein, the proteomic and functional analyses of high density lipoprotein (HDL) subclasses were performed in humans and rats.MethodsAfter purifying S/M/L-HDL subclasses from healthy humans (n = 6) and rats (n = 3) using fast protein liquid chromatography (FPLC) with calcium silica hydrate (CSH) resin, the proteomic analysis by mass spectrometry was conducted, as well as the capacities of cholesterol efflux and antioxidation was measured.ResultsOf the 120 and 106 HDL proteins identified, 85 and 68 proteins were significantly changed in concentration among the S/M/L-HDL subclasses in humans and rats, respectively. Interestingly, it was found that the relatively abundant proteins in the small HDL (S-HDL) and large HDL (L-HDL) subclasses did not overlap, both in humans and in rats. Next, by searching for the biological functions of the relatively abundant proteins in the HDL subclasses via Gene Ontology, it was displayed that the relatively abundant proteins involved in lipid metabolism and antioxidation were enriched more in the medium HDL (M-HDL) subclass than in the S/L-HDL subclasses in humans, whereas in rats, the relatively abundant proteins associated with lipid metabolism and anti-oxidation were enriched in M/L-HDL and S/M-HDL, respectively. Finally, it was confirmed that M-HDL and L-HDL had the highest cholesterol efflux capacity among the three HDL subclasses in humans and rats, respectively; moreover, M-HDL exhibited higher antioxidative capacity than S-HDL in both humans and rats.ConclusionsThe S-HDL and L-HDL subclasses are likely to have different proteomic components during HDL maturation, and results from the proteomics-based comparison of the HDL subclasses may explain the associated differences in function.

Plasma High Density Lipoprotein Small Subclass is Reduced in Alzheimer's Disease Patients and Correlates with Cognitive Performance.

Background:The link between cholesterol and Alzheimer’s disease (AD) has received much attention, as evidence suggests high levels of cholesterol might be an AD risk factor. The carriage of cholesterol and lipids through the body is mediated via lipoproteins, some of which, particularly apolipoprotein E (ApoE), are intimately linked with AD. In humans, high density lipoprotein (HDL) is regarded as a “good” lipid complex due to its ability to enable clearance of excess cholesterol via ‘cholesterol reverse transport’, although its activities in the pathogenesis of AD are poorly understood. There are several subclasses of HDL; these range from the newly formed small HDL, to much larger HDL.Objective:We examined the major subclasses of HDL in healthy controls, mild cognitively impaired, and AD patients who were not taking statins to determine whether there were HDL profile differences between the groups, and whether HDL subclass levels correlated with plasma amyloid-β (Aβ) levels or brain Aβ deposition.Methods:Samples from AIBL cohort were used in this study. HDL subclass levels were assessed by Lipoprint while Aβ1–42 levels were assessed by ELISA. Brain Aβ deposition was assessed by PET scan. Statistical analysis was performed using parametric and non-parametric tests.Results:We found that small HDL subclass is reduced in AD patients and it correlates with cognitive performance while plasma Aβ concentrations do not correlate with lipid profile or HDL subfraction levels.Conclusion:Our data indicate that AD patients exhibit altered plasma HDL profile and that HDL subclasses correlate with cognitive performances.

Small HDL subclass is associated with coronary plaque stability: An optical coherence tomography study in patients with coronary artery disease

The role of high-density lipoprotein (HDL) subclasses in atherosclerotic diseases remains an open question. Previous clinical trials have attempted to explore the predictive effect of HDL subspecies on cardiovascular risk. However, no studies have assessed the connections between these subclasses and characteristics of plaque microstructure. To investigate the relationship of HDL subclasses and coronary plaque stability assessed by optical coherence tomography (OCT). Morphological characteristics of 160 nontarget lesions from 85 patients with coronary artery disease were assessed by OCT. HDL subclass profiles were analyzed using nondenaturing polyacrylamide gel electrophoresis. The plasma levels of small HDL subclass (percentage or concentration) were found to be positively associated with fibrous cap thickness (r=0.232, P=.007; r=0.243, P=.005) and negatively with maximum lipid arc (r=-0.240, P=.005; r=-0.252, P=.003) and lipid core length (r=-0.350, P<.001; r=-0.367, P<.001). Multivariate logistic regression analysis showed the small HDL subclass (percentage or concentration) (odds ratio [OR]: 0.457, 95% confidence interval [CI]: 0.214-0.974, P=.043; OR: 0.438, 95% CI: 0.204-0.938, P=.034) to be an independent factor in predicting OCT-detected thin-cap fibroatheroma of nontarget lesions. High levels of small HDL are associated with coronary nontarget plaque stability. Our findings suggest that the small HDL subtype might represent the atheroprotective activity of HDL.

Reduced plasma levels of small HDL particles transporting fibrinolytic proteins in pulmonary arterial hypertension

BackgroundAberrant lipoprotein metabolism has been implicated in experimental pulmonary hypertension, but the relevance to patients with pulmonary arterial hypertension (PAH) is inconclusive.ObjectiveTo investigate the relationship between circulating lipoprotein subclasses and...

Effects of co-existing autoimmune diseases on serum lipids and lipoprotein subclasses profile in paediatric patients with type 1 diabetes mellitus

ObjectivePaediatric patients with type 1 diabetes mellitus (T1DM) frequently develop other autoimmune disorders; most commonly autoimmune thyroiditis (ATD) and celiac disease (CD). In this study we evaluated whether co-existing autoimmune diseases had significant impact on lipid and lipoprotein subclasses, as known cardiovascular risk factors in T1DM. Design and methodsStudy included 201 subjects with T1DM (14.1 ± 2.9 years) and 141 age- and gender-matched controls. ATD was presented in 30 and CD in 15 T1DM patients. Serum lipid parameters were determined by routine laboratory methods and plasma low-density (LDL) and high-density lipoprotein (HDL) subclasses by gradient-gel electrophoresis method. ResultsBoth groups of T1DM patients with concomitant autoimmune disease had significantly lower HDL-C levels (P < 0.05) than the patients with T1DM only, but comparable to control group (P = 0.436). T1DM patients had significantly higher (P < 0.001) proportion of small HDL subclasses than controls. Mean value of atherosclerosis index in patients with T1DM + CD was the highest (1.75 ± 0.86) and it was significantly higher than the index in patients with T1DM only (1.33 ± 0.51; P < 0.05). LDL size did not differ between the groups of T1DM patients and control group (P = 0.619). The size of HDL particles was significantly reduced (P < 0.05) in the groups with associated autoimmune diseases. The patients with co-existing autoimmune diseases had higher risk of low HDL-C level (OR: 2.96; P < 0.05). ConclusionsThe results have shown significant impact of co-existing autoimmune diseases on lipid profile in patients with T1DM. The most prominent changes were found in HDL lipoprotein characteristics in T1DM + CD group.

Different inverse association of large high-density lipoprotein subclasses with exacerbation of insulin resistance and incidence of type 2 diabetes: The Nagahama study.

In addition to its antiatherogenic action, high-density lipoprotein (HDL) may also have an antidiabetes function. Although the biological actions of small HDL (HDL3) and large HDL (HDL2) subclasses may be different, evidence in support of that hypothesis is lacking. The aim of this study was to clarify the difference in prognostic significance of HDL subclasses for exacerbation of insulin resistance and incidence of type 2 diabetes in the general population. Study participants included 8365 community residents 52±13years of age not taking lipid lowering drugs. Serum HDL cholesterol subclasses and low-density lipoprotein subclasses, were measured by a homogeneous assay. Insulin resistance was assessed by homeostasis model assessment of insulin resistance (HOMA-IR). Cross-sectional analysis adjusted for possible covariates found that HDL2 cholesterol (HDL2-C) levels were inversely associated with HOMA-IR (β=-0.169, p<0.001), whereas HDL3-C had the opposite association (β=0.054, p<0.001). Similar results were found in an analysis for type 2 diabetes (HDL2-C, odds ratio=0.96, p=0.001; HDL3-C, odds ratio=1.04, p=0.181). In a longitudinal analysis with 5.0years of follow-up, HDL2-C was inversely associated with exacerbation of insulin resistance (β=-0.163, p<0.001); HDL3-C had the opposite association (β=0.026, p=0.037). During follow-up, 205 individuals were newly diagnosed with diabetes, and HDL2-C level was associated with an inverse risk of type 2 diabetes incidence (odds ratio=0.98, p=0.006). HDL may have an antidiabetic function; the prognostic value of HDL2-C for diabetes and insulin resistance might be better than that of HDL3-C.

Dietary Resistant Starch Supplementation Increases High-Density Lipoprotein Particle Number in Pigs Fed a Western Diet

ABSTRACTResistant starch (RS) has been well characterized for its glycemic control properties; however, there is little consensus regarding the influence of RS on blood lipid concentrations and lipoprotein distribution and size. Therefore, this study aimed to characterize the effect of daily RS supplementation in a controlled capsule delivery on biomarkers of cardiovascular (blood lipids, lipoproteins) and diabetes (glucose, insulin) risk in a pig model. Twelve 8-week-old male Yorkshire pigs were placed on a synthetic Western diet and randomly divided into two groups (n = 6/group) for 30 days: (1) a placebo group supplemented with capsules containing unmodified pre-gelatinized potato starch (0 g/RS/day); and (2) an RS group supplemented with capsules containing resistant potato starch (10 g/RS/day). Serum lipids including total-cholesterol (C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides did not differ (p > 0.05) between the RS and placebo groups. Although the total numbers of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) particles were similar (p > 0.05) between the two groups, total high-density lipoprotein (HDL) particles were higher (+28%, p < 0.05) in the RS group compared with placebo, resulting from an increase (p < 0.05) in the small HDL subclass particles (+32%). Compared with the placebo group, RS supplementation lowered (p < 0.05) fasting serum glucose (−20%) and improved (p < 0.05) insulin resistance as estimated by Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) without a change in insulin. Additionally, total serum glucagon-like-peptide 1 (GLP-1) was higher (+141%, p < 0.05) following RS supplementation compared with placebo. This data suggests that in addition to the more well-characterized effect of RS intake in lowering blood glucose and improving insulin sensitivity, the consumption of RS may be beneficial in lipid management strategies by enhancing total HDL particle number.

Association between ethnicity and obesity with high-density lipoprotein (HDL) function and subclass distribution.

BackgroundObesity and low high-density lipoprotein-cholesterol (HDL-C) levels are associated with cardiovascular risk. Surprisingly, despite a greater prevalence of obesity and lower HDL concentrations than white women, black South African women are relatively protected against ischaemic heart disease.MethodsWe investigated whether this apparent discrepancy may be related to different HDL function and subclass distribution in black and white, normal-weight and obese South African women (n = 40). HDL functionality was assessed by measuring paraoxonase (PON) activity, platelet activating factor acetylhydrolase (PAF-AH) activity, Oxygen Radical Absorbance Capacity (ORAC) and quantification of the expression of vascular cell adhesion molecule in endothelial cells. PON-1 and PAF-AH expression was determined in isolated HDL and serum using Western blotting. Levels of large, intermediate and small HDL subclasses were measured using the Lipoprint® system.ResultsPON activity was lower in white compared to black women (0.49 ± 0.09 U/L vs 0.78 ± 0.10 U/L, p < 0.05), regardless of PON-1 protein levels. Obese black women had lower PAF-AH activity (9.34 ± 1.15 U/L vs 13.89 ± 1.21 U/L, p <0.05) and HDL-associated PAF-AH expression compared to obese white women. Compared to normal-weight women, obese women had lower large HDL, greater intermediate and small HDL; an effect that was more pronounced in white women than black women. There were no differences in antioxidant capacity or anti-inflammatory function across groups.ConclusionsOur data show that both obesity and ethnicity are associated with differences in HDL functionality, while obesity was associated with decreases in large HDL subclass distribution. Measuring HDL functionality and subclass may, therefore, be important factors to consider when assessing cardiovascular risk.Electronic supplementary materialThe online version of this article (doi:10.1186/s12944-016-0257-9) contains supplementary material, which is available to authorized users.

HDL subclasses are heterogeneous in their associations with body fat, as measured by dual-energy X-ray absorptiometry: The Kitakata Kids Health Study

BackgroundObesity, defined as the excessive accumulation of body fat, is frequently associated with low concentrations of high-density lipoprotein (HDL) cholesterol. However, HDL particles are heterogeneous in size and composition. HDL subclasses may be differentially associated with body fat. MethodsThis study investigated associations between the cholesterol concentrations of HDL subclasses, as determined by high-performance liquid chromatography, and body fat variables, as measured by dual-energy X-ray absorptiometry. The source population was all ninth grade students who attended Shiokawa Junior High School in Japan. ResultsCross-sectional data on body fat and serum HDL subclasses were obtained for 87 students (72.5% of the source population). The cholesterol concentration of the large HDL subclass showed a significant (P<0.05) inverse relationship with whole body fat and trunk fat (r=−0.24 and −0.30), whereas the concentration of the small HDL subclass showed a significant positive relationship with these body fat variables (r=0.25 and 0.31). After adjusting for potential confounding factors, the mean concentration of small HDL significantly increased from the lowest to highest tertiles of trunk fat mass index. ConclusionThese results indicate that HDL subclasses are heterogeneous in their associations with body fat variables that were accurately measured by dual-energy X-ray absorptiometry among Japanese students.

High-Density Lipoprotein Particle Subclass Heterogeneity and Incident Coronary Heart Disease

Raising the cholesterol of high-density lipoprotein (HDL) particles is targeted as a cardiovascular disease prevention strategy. However, HDL particles are heterogeneous in composition and structure, which may relate to differences in antiatherogenic potential. We prospectively evaluated the association of HDL subclasses, defined by a recently proposed nomenclature, with incident coronary heart disease (CHD). Baseline HDL particle concentrations were measured by nuclear magnetic resonance spectroscopy and categorized into 5 subclasses (very large, large, medium, small, and very small) among 26 332 initially healthy women. During a median follow-up of 17 years, 969 cases of incident CHD (myocardial infarction, revascularization, and CHD death) were ascertained. In Cox models that adjusted for age, race/ethnicity, blood pressure, smoking, postmenopausal status, and hormone therapy, associations with incident CHD were inverse (P trend<0.0001) for concentrations of very large (hazard ratio for top versus bottom quartile, 0.49; 95% confidence interval, 0.41-0.60), large (0.54; 0.45-0.64), and medium (0.69; 0.58-0.83) HDL subclasses. Conversely, hazard ratios (95% confidence intervals) for small and very small HDL were 1.22 (1.01-1.46; P trend=0.08) and 1.67 (1.39-2.02; P trend<0.0001), respectively. However, after additionally adjusting for metabolic and lipoprotein variables, associations for the spectrum of large, medium, and small HDL subclasses were inverse (P trend<0.05 for large and small and 0.07 for medium), whereas subclasses at either end of the spectrum were not associated with CHD (P trend=0.97 for very large and 0.21 for very small HDL). In this prospective study, associations with incident CHD differed by HDL particle subclass, which may be relevant for developing HDL-modulating therapies. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000479.

Increased plasma visfatin concentration is a marker of an atherogenic metabolic profile

Background and aimsVisfatin is associated with atherosclerosis-related diseases. We assessed in non-diabetic individuals the association of plasma visfatin levels with cardiovascular disease (CVD) risk and the atherosclerosis-related metabolic variables. Methods and resultsWhen study population (n = 179, age 49 ± 11 years) was divided according to visfatin tertiles, the 10-year CVD Framingham risk scores were significantly increased in the top visfatin tertile. We observed a positive association between visfatin tertiles with waist circumference and blood pressure, as well as with total cholesterol and triglyceride levels, but not with apolipoprotein C-III, fibrinogen or pre-beta1 high density lipoprotein (HDL). The percentage of large HDL subclasses was significantly lower and the percentage of small HDL subclasses over the HDL-C concentration was significantly higher in the top visfatin tertile compared with the other tertiles. The atherogenic small dense low density lipoprotein subclasses (sdLDL-C) were significantly increased in the top visfatin tertile compared with the lower tertiles. High sensitivity C-reactive protein (hsCRP) concentration was significantly increased in the top visfatin tertile compared with the lower tertiles. Although age and sex distribution did not differ between visfatin tertiles, the simultaneous adjustment for these parameters attenuated the significance of the differences observed in sdLDL-C and hsCRP levels. Similarly, after adjustment for hsCRP or waist circumference, only triglycerides and blood pressure levels, as well as the distribution of HDL subclasses, remained significantly different between visfatin tertiles. ConclusionsOur results support a role for visfatin in the detection of subjects with many metabolic abnormalities, which result in increased CVD risk.

Effect of fenofibrate therapy and ABCA1 polymorphisms on high-density lipoprotein subclasses in the Genetics of Lipid Lowering Drugs and Diet Network

Previous studies have shown that ATP-binding cassette transporter 1 (ABCA1) polymorphisms associated with increased ABCA1 expression result in increased small HDL (high-density lipoprotein) subclass particle concentration. This study examines the effect of treatment with fenofibrate, a drug known to bind peroxisome proliferator-activated receptor alpha (PPARalpha) which increases the expression of ABCA1 gene, on lipoprotein subclass profiles of individuals stratified by ABCA1 genotypes. Participants of Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) were treated with fenofibrate over a three week period. We analyzed six ABCA1 polymorphisms in 287 GOLDN participants with triglyceride concentrations >or=150mg/dL and studied their associations with HDL subclass particle concentrations, as measured by nuclear magnetic resonance spectroscopy, before and after treatment. Fenofibrate treatment did not result in significant changes in small HDL subclass particle concentration. When changes in HDL subclasses were stratified by ABCA1 polymorphism genotypes, there were no statistically significant associations between ABCA1 genotypes and small HDL subclasses before fenofibrate treatment. However, after fenofibrate treatment the KK genotype of R1587K (mean 4.40micromol/L; p=0.004) and the RK genotype of R219K (mean 1.60micromol/L; p=0.02) polymorphisms were associated with significantly increased small HDL. The R1587KKK genotype (mean 4.80micromol/L; p=0.0002) and the R219K KK genotype (mean 2.50micromol/L; p=0.02) were also associated with increased HDL particle concentrations. There is a synergistic effect between ABCA1 polymorphisms and fenofibrate. Thus, our study indirectly confirms the role of fenofibrate and genotype in increasing cholesterol efflux, as evidenced by increased small HDL particles.

Low-Density Lipoprotein and High-Density Lipoprotein Particle Subclasses Predict Coronary Events and Are Favorably Changed by Gemfibrozil Therapy in the Veterans Affairs High-Density Lipoprotein Intervention Trial

Changes in conventional lipid risk factors with gemfibrozil treatment only partially explain the reductions in coronary heart disease (CHD) events experienced by men in the Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT). We examined whether measurement of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particle subclasses provides additional information relative to CHD risk reduction. This is a prospective nested case-control study of 364 men with a new CHD event (nonfatal myocardial infarction or cardiac death) during a 5.1-year (median) follow-up and 697 age-matched controls. Nuclear magnetic resonance (NMR) spectroscopy was used to quantify levels of LDL and HDL particle subclasses and mean particle sizes in plasma obtained at baseline and after 7 months of treatment with gemfibrozil or placebo. Odds ratios for a 1-SD increment of each lipoprotein variable were calculated with adjusted logistic regression models. Gemfibrozil treatment increased LDL size and lowered numbers of LDL particles (-5%) while raising numbers of HDL particles (10%) and small HDL subclass particles (21%). Concentrations of these LDL and HDL particles achieved with gemfibrozil were significant, independent predictors of new CHD events. For total LDL and HDL particles, odds ratios predicting CHD benefit were 1.28 (95% CI, 1.12 to 1.47) and 0.71 (95% CI, 0.61 to 0.81), respectively. Mean LDL and HDL particle sizes were not associated with CHD events. The effects of gemfibrozil on NMR-measured LDL and HDL particle subclasses, which are not reflected by conventional lipoprotein cholesterol measures, help to explain the demonstrated benefit of this therapy in patients with low HDL cholesterol.

Small high density lipoprotein subclasses: some of their physico-chemical properties and stability in solution.

Small high density lipoproteins (SHDL) contribute to the protection from atherosclerosis, but detailed information about their properties is not available yet. We isolated four of the smallest HDL subclasses that contain apoA-I alone, the small lipoprotein A-I (SLpAI), by their separation on gradient polyacrylamide gel followed by electroelution. Their physico-chemical properties were calculated from their displacement in non-denaturing gradient polyacrylamide gel under the effect of electrical potential. The properties are: Stokes' radii 2.96-3.56 nm; molecular masses 42-70 kDa; net negative charge 7.2-13.5; surface charge densities 3139-4069 -esu.cm(-2); surface potentials 10.6-15.7 -mV; coefficients of friction 5.74-6.90 x 10(-8) g.s(-1); and diffusion coefficients 5.76-6.94 x 10(-7) cm(2).s(-1). We found that these particles were of low stability as they underwent molecular transformation into larger particles on storage. The estimated dimensions of these particles do not support ellipsoidal shape, therefore, the most probable shape is spherical; consequently, their hydrated characteristics were estimated. We conclude that these particles have high values of negative surface charge and diffusion coefficients, and are of low stability. Their small Stokes' radii were similar to each other and they are spherical and highly hydrated.

Measurement of small high density lipoprotein subclass by an improved immunoblotting technique

An improved method of immunoblotting of plasma onto agarose gel matrix containing antiapolipoprotein A-I is described. Fresh plasma samples were subjected to gradient polyacrylamide gel electrophoresis (4-25%) followed by electrotransfer onto agarose gel layer containing antiapolipoprotein A-I. This method was compared with immunoblotting onto nitrocellulose where the transfer onto agarose gel matrix has been shown to be more convenient, quantitative, and can be kept permanently. Plasma apolipoprotein A-I was found to be distributed among regions of varying molecular weights ranging from 43,000 to 800,000. A small size fraction of molecular weight range of 43,000-50,000 (small HDL) was found in normolipidemic and hyperlipidemic subjects. The proportion of the latter fraction varied considerably among subjects (range: 0.0-32%), being lower in normolipidemic subjects (mean +/- SEM: 11.6 +/- 1.4%), and higher in hyperlipidemic subjects (mean +/- SEM: 23.7 %/- 1.7%, P < 0.001). Physiological increase in the level of the small HDL was observed in normolipidemic subjects 4 h after fat ingestion (difference: 5.0%, P < 0.001); moreover, the level was higher in normolipidemic subjects who consumed moderate amounts of alcohol (mean +/- SEM: 17.9 +/- 1.2%, P < 0.001) compared with normolipidemic subjects who do not drink alcohol at all.