Large High-density Lipoprotein Subclasses 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.

Integrating Metabolomics, Genomics, and Disease Pathways in Age-Related Macular Degeneration: The EYE-RISK Consortium

The current study aimed to identify metabolites associated with age-related macular degeneration (AMD) by performing the largest metabolome association analysis in AMD to date, as well as aiming to determine the effect of AMD-associated genetic variants on metabolite levels and investigate associations between the identified metabolites and activity of the complement system, one of the main AMD-associated disease pathways. Case-control association analysis of metabolomics data. Five European cohorts consisting of 2267 AMD patients and 4266 control participants. Metabolomics was performed using a high-throughput proton nuclear magnetic resonance metabolomics platform, which allows quantification of 146 metabolite measurements and 79 derivative values. Metabolome-AMD associations were studied using univariate logistic regression analyses. The effect of 52 AMD-associated genetic variants on the identified metabolites was investigated using linear regression. In addition, associations between the identified metabolites and activity of the complement pathway (defined by the C3d-to-C3 ratio) were investigated using linear regression. Metabolites associated with AMD. We identified 60 metabolites that were associated significantly with AMD, including increased levels of large and extra-large high-density lipoprotein (HDL) subclasses and decreased levels of very low-density lipoprotein (VLDL), amino acids, and citrate. Of 52 AMD-associated genetic variants, 7 variants were associated significantly with 34 of the identified metabolites. The strongest associations were identified for genetic variants located in or near genes involved in lipid metabolism (ABCA1, CETP, APOE, and LIPC) with metabolites belonging to the large and extra-large HDL subclasses. Also, 57 of 60 metabolites were associated significantly with complement activation levels, independent of AMD status. Increased large and extra-large HDL levels and decreased VLDL and amino acid levels were associated with increased complement activation. Lipoprotein levels were associated with AMD-associated genetic variants, whereas decreased essential amino acids may point to nutritional deficiencies in AMD. We observed strong associations between the vast majority of the AMD-associated metabolites and systemic complement activation levels, independent of AMD status. This may indicate biological interactions between the main AMD disease pathways and suggests that multiple pathways may need to be targeted simultaneously for successful treatment of AMD.

HDL Subclass Distribution Shifts with Increasing Central Adiposity.

Although cross-sectional studies have shown that obesity is associated with lower concentrations of large high-density lipoprotein (HDL) subclasses, it is unknown if changes in HDL subclasses are related to changes in body fat and its distribution over time. We therefore assessed changes in HDL subclass distribution over a 5.5-year free-living follow-up period in 24 black South African women. At baseline and follow-up, body composition and body fat distribution were measured using anthropometry, dual X-ray absorptiometry, and computerized tomography. HDL subclass distribution was quantified using Lipoprint®. Over the 5.5-year follow-up period, body fat (+17.3 ± 4.5 kg, p < 0.05) and trunk fat mass (+7.4 ± 1.9%, % fat mass, FM, p < 0.05) increased, while leg fat mass (−2.53 ± 0.56%, % FM, p < 0.001) and the distribution of large (−6.43 ± 2.12%, p < 0.05) HDL subclasses decreased. A percentage decrease in large HDL subclasses was associated with a percentage increase in central fat mass (visceral adipose tissue (VAT) area, p < 0.05) and a percentage decrease in peripheral fat mass (leg fat mass). These preliminary findings suggest that a relative redistribution of body fat from the periphery to the abdominal region were associated with a decrease HDL subclass size in black South African women and provide a novel link between body fat distribution and lipidology in this population.

Potential Impact on Lipoprotein Subfractions in Type 2 Diabetes.

Introduction:Recently, the sodium-glucose cotransporter2 (SGLT2) inhibitor empagliflozin has been shown to lower cardiovascular risk among diabetic patients. It is intriguing that some SGLT2 inhibitors have been found to increase low-density lipoprotein (LDL) cholesterol levels, while the relevance to high-density lipoprotein (HDL) cholesterol is unknown. Although the inhibitory effect of SGLT2 inhibitors on glucose reabsorption may accelerate compensatory lipid metabolism and subsequently reduce body weight and affect the lipid profile, much remains unclear about this mechanism. Therefore, we conducted this study to investigate in detail how canagliflozin affects lipoprotein fractions including LDL and HDL subclasses.Materials and Methods:This study is a multicenter prospective study. The participants were patients with 22 type 2 diabetes (60.7 ± 11.6 years, 59.1% of men) who had HbA1c ⩾ 7.0% and consented to participate in the study. They were administered 100 mg canagliflozin orally once per day. Biochemistry test and cholesterol levels of 20 lipoprotein fractions (G1-G20) using high performance liquid chromatography methods were examined before and after 12 weeks of treatment period.Results:Significant decreases were observed in the participants’ body weight (69.7 to 67.9 kg, P < .001), systolic blood pressure (129.3 to 119.5 mm Hg, P < .01), and HbA1c (8.5% to 7.4%, P < .001). Cholesterol levels in the 20 lipoprotein fractions increased for very large HDL (G14, G15) and large HDL (G16) (P < .05).Conclusions:Reduction in body weight, improvement of blood glucose levels, and increases in very large HDL and large HDL subclasses were observed after canagliflozin treatment. These beneficial changes might contribute to subsequent suppression of cardiovascular outcomes.

Differential expression of osteopontin, and osteoprotegerin mRNA in epicardial adipose tissue between patients with severe coronary artery disease and aortic valvular stenosis: association with HDL subclasses

BackgroundPrevious studies suggest a relationship of the epicardial adipose tissue (EAT) with progression and calcification of the atherosclerotic plaque; however, it is unknown if this tissue expresses genes that may participate on these processes and if the expression of these genes is regulated by high-density lipoprotein (HDL) subclasses.MethodsTo explore this possibility, we determined the mRNA expression by qPCR of a pro-calcifying gene (osteopontin (OPN)), and two anti-calcifying genes (osteoprotegerin (OPG) and osteonectin (ON)), in biopsies of EAT obtained from 15 patients with coronary artery disease (CAD) determined by angiography, and 15 patients with diagnostic of aortic valve stenosis but without CAD as control group. We determined the distribution and composition of HDL subclasses by electrophoresis and their statistical relationship with the gene expression in EAT.ResultsEAT from CAD patients showed a higher expression level of OPN and OPG than control group, whereas ON expression was similar between groups. Large HDL subclasses were cholesterol-poor in CAD patients as estimated by the cholesterol-to-phospholipid ratio. A linear regression model showed an independent association of OPN expression with HDL3a-cholesterol, and OPG expression with the relative proportion of HDL3b protein. Logistic analysis determined that OPN expression was positively associated with the presence of atherosclerotic plaqueConclusionOPN, ON, and OPG genes are transcribed in EAT; to the exception of ON, the level of expression was different in CAD patients and control group, and correlated with some HDL subclasses, suggesting a new role of these lipoproteins.

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.

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.

Effect of Ezetimibe on Low‐and High‐Density Lipoprotein Subclasses in Sitosterolemia

Sitosterolemia (STSL) is a rare sterol disease manifested by very high plasma phytosterols (PS) with normal to high total cholesterol (TC) levels and increased atherosclerosis risk. Low density lipoprotein (LDL), intermediate density lipoprotein (IDL) and very lowdensity lipoprotein (VLDL) cholesterols are proatherogenic while high density lipoprotein (HDL) cholesterol is antiatherogenic. Ezetimibe (EZ), a sterol absorption inhibitor, can reduce plasma PS and TC levels in STSL but its effect on lipoprotein subclasses has not been studied. We evaluated the effect of EZ on lipoprotein subclasses in STSL patients (pts, n=8) taken off EZ for 14 wks then placed on EZ (10 mg/d) for 14 wks. Serum total lipids and subfractions were measured enzymatically or with the Lipoprint system. Data (mean±SEM) were analyzed by paired t‐test. EZ reduced serum TC (‐13±4%, p=0.02), VLDL (‐24±4%, p=0.002) and total LDL (‐17±6%, p=0.03) levels vs off EZ. Reduced LDL values were due to decreased IDLB and C (‐22±7 and ‐21±8%, p&lt;0.05), not to large, buoyant LDL subclasses (LDL1: ‐8±8%, p=0.23 and LDL2: +35±55%, p=0.17). LDL size did not change with EZ (275±0 vs 274±1 Å, p=0.18). EZ increased HDL levels (26±8%, p=0.008) due to increased intermediate (34±14%, p=0.02) and large (33±16%, p=0.06) HDL subclasses. These data suggest EZ can favorably affect LDL and HDL subfractions distribution, thus providing potential clinical benefit in STSL beyond reducing TC and PS accrual.Funded by NIH and CIHR

Effect of Colesevelam HCl Monotherapy on Lipid Particles in Type 2 Diabetes Mellitus

PurposeIn addition to lowering hemoglobin A1C, colesevelam has been shown to improve the atherogenic lipoprotein profile of subjects with type 2 diabetes mellitus (T2DM) when used in combination with metformin and/or sulfonylureas. A recent study evaluated the effects of colesevelam as antidiabetes monotherapy in adults with T2DM who had inadequate glycemic control (hemoglobin A1C ≥7.5 to ≤9.5 %) with diet and exercise alone; we report here the effects on lipoprotein particle subclasses.MethodsSubjects were randomized to receive oral colesevelam 3.75 g/day (n = 176) or placebo (n = 181) for 24 weeks. Changes in lipoprotein particle subclasses were determined by nuclear magnetic resonance spectroscopy.ResultsAt Week 24 with last observation carried forward, colesevelam produced a reduction in total low-density lipoprotein (LDL) particle concentration (baseline: 1,611 nmol/L; least-squares [LS] mean treatment difference: −143 nmol/L, p < 0.0001) versus placebo; reductions were also seen in large, small, and very small LDL particle concentrations (all p < 0.05). There was also a reduction in total very low-density lipoprotein (VLDL) and chylomicron particle concentration (baseline: 88 nmol/L; LS mean treatment difference: −1 nmol/L, p = 0.82) that resulted from a lowering in small VLDL particle concentration (baseline: 45 nmol/L; LS mean treatment difference: −5 nmol/L, p = 0.03). In addition, with colesevelam there was an increase in total high-density lipoprotein (HDL) particle concentration versus placebo (baseline: 31 μmol/L; LS mean treatment difference: +0.6 μmol/L, p = 0.20), due to increases in the large (baseline: 5 μmol/L; LS mean treatment difference: +0.5 μmol/L, p = 0.007) and medium (baseline: 3 μmol/L; LS mean treatment difference: +0.8 μmol/L, p = 0.02) HDL subclasses.ConclusionsColesevelam monotherapy in subjects with T2DM resulted in generally favorable changes in certain lipoprotein subclass profiles compared with placebo.

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.

Effects of fenofibrate on lipid profiles, cholesterol ester transfer activity, and in-stent intimal hyperplasia in patients after elective coronary stenting

BackgroundThe association between modulation of detailed lipoprotein profiles and cholesterol ester transfer (CET) activity by peroxisome proliferator-activated receptor (PPAR)-a agonists in patients with coronary artery disease remains unclear. We assessed lipid profiles, plasma CET activity, and in-stent intimal hyperplasia after fenofibrate treatment in patients who underwent elective coronary stenting.MethodsForty-three consecutive patients who underwent elective coronary stenting were randomized to the fenofibrate group (300 mg/day for 25 weeks, n = 22) or the control group (n = 21). At baseline and follow up, CET activity and lipoprotein profiles were measured, and quantitative coronary angiography was performed.ResultsIn the fenofibrate group, the levels of large very low-density lipoprotein cholesterol, and small low-density lipoprotein (LDL) cholesterol decreased and those of small high-density lipoprotein (HDL) cholesterol increased. Besides, CET activity decreased independent of the effect of fenofibrate on total and LDL cholesterol. The reduction of CET activity significantly correlated with the increase in LDL particle size (r = 0.47, P = 0.03) and the decrease of triglycerides in large HDL subclasses (r = 0.48, P = 0.03). Although there were no significant differences in restenosis parameters between the two groups, low CET activity significantly correlated with the inhibition of neointimal hyperplasia (r = 0.56, P = 0.01).ConclusionsFenofibrate inhibited CET activity and thereby improved atherogenic lipoprotein profiles, and reduced intimal hyperplasia after coronary stenting.