Search

Background and aims Research on the biologic activities of HDL, such as cholesterol efflux capacity and HDL composition, has allowed the understanding of the effect of interventions directed to improve cardiovascular risk. Previously, statin therapy has shown conflicting results about its effects on cholesterol efflux capacity of HDL; the underlying mechanisms are unclear but studies with positive effects are associated with an increase of HDL-cholesterol levels. We investigated if 10 weeks of atorvastatin therapy changes HDL efflux capacity and the chemical composition of its subpopulations. Methods In a before-after design basis, HDL-cholesterol levels, chemical composition and cholesterol efflux capacity from HDL subpopulations isolated by isophynic ultracentrifugation were assessed in plasma samples from 60 patients with type 2 diabetes mellito (T2DM) at baseline and after 10 weeks of treatment with 20 mg atorvastatin. Cholesterol efflux was measured from human THP-1 cells using large, light HDL2b and small, dense 3c subpopulations as well as total HDL as acceptors. Changes of cholesterol efflux and chemical composition of HDL after treatment were analyzed. Correlations among variables potentially involved in cholesterol efflux were evaluated. Results A significant decrease of 4% in HDL-cholesterol levels was observed from 47 (42–54) to 45 (39–56) mg/dL, p = 0.02. Cholesterol efflux from total-HDL and HDL2b and 3c subfractions was maintained unchanged after treatment. The total mass of HDL remained unaffected, except for the HDL3a subpopulation accounted for by a significant increase in total protein content. No significant correlations for variables previously known to be associated with cholesterol efflux were found in our study. Conclusions Short therapy of 10 weeks with 20 mg of atorvastatin does not modify the cholesterol efflux capacity neither the total mass of HDL2b, HDL3c and total HDL. The discrepancy with previous reports may be due to the selective effects among different classes of statins or differences in the approaches to measure cellular cholesterol efflux.

IF 4.810; International audience; The functional heterogeneity of HDL is attributed to its diverse bioactive components. We evaluated whether the vasodilatory effects of HDL differed across HDL subpopulations, reflecting their distinct molecular composition. The capacity of five major HDL subfractions to counteract the inhibitory effects of oxidized LDL on acetylcholine-induced vasodilation was tested in a rabbit aortic rings model. NO production, an essential pathway in endothelium-dependent vasorelaxation, was studied in simian vacuolating virus 40-transformed murine endothelial cells (SVECs). Small dense HDL3 subfractions displayed potent vasorelaxing activity (up to +31% vs. baseline, P < 0.05); in contrast, large light HDL2 did not induce aortic-ring relaxation when compared on a total protein basis. HDL3 particles were enriched with sphingosine-1-phosphate (S1P) (up to 3-fold vs. HDL2), with the highest content in HDL3b and -3c that concomitantly revealed the strongest vasorelaxing properties. NO generation was enhanced by HDL3c in SVECs (1.5-fold, P < 0.01), a phenomenon that was blocked by the S1P receptor antagonist, VPC 23019. S1P-enriched reconstituted HDL (rHDL) was a 1.8-fold (P < 0.01) more potent vasorelaxant than control rHDL in aortic rings. Small dense HDL3 particles displayed potent protective effects against oxidative stress-associated endothelium dysfunction, potentially reflecting their elevated content of S1P that might facilitate interaction with S1P receptors and ensuing NO generation.

To evaluate functional and compositional properties of HDL in subjects from a kindred of genetic apoA-I deficiency, two homozygotes and six heterozygotes, with a nonsense mutation at APOA1 codon -2, Q[-2]X, were recruited together with age- and sex-matched healthy controls (n = 11). Homozygotes displayed undetectable plasma levels of apoA-I and reduced levels of HDL-cholesterol (HDL-C) and apoC-III (5.4% and 42.6% of controls, respectively). Heterozygotes displayed low HDL-C (21 ± 9 mg/dl), low apoA-I (79 ± 24 mg/dl), normal LDL-cholesterol (132 ± 25 mg/dl), and elevated TG (130 ± 45 mg/dl) levels. Cholesterol efflux capacity of ultracentrifugally isolated HDL subpopulations was reduced (up to -25%, P < 0.01, on a glycerophospholipid [GP] basis) in heterozygotes versus controls. Small, dense HDL3 and total HDL from heterozygotes exhibited diminished antioxidative activity (up to -48%, P < 0.001 on a total mass basis) versus controls. HDL subpopulations from both homozygotes and heterozygotes displayed altered chemical composition, with depletion in apoA-I, GP, and cholesteryl ester; enrichment in apoA-II, free cholesterol, and TG; and altered phosphosphingolipidome. The defective atheroprotective activities of HDL were correlated with altered lipid and apo composition. These data reveal that atheroprotective activities of HDL particles are impaired in homozygous and heterozygous apoA-I deficiency and are intimately related to marked alterations in protein and lipid composition.

Background and aimsIron deficiency anemia (IDA) affects around 20?30% of adults worldwide. An association between IDA and cardiovascular disease (CVD) has been reported. Oxidative stress, inflammation and low concentration of high-density lipoproteins (HDL) were implicated on endothelial dysfunction and CVD in IDA. We studied the effects of iron deficiency and of an intravenous iron administration on oxidative stress and HDL characteristics in IDA women.MethodsTwo studies in IDA women are presented: a case-control study, including 18 patients and 18 age-matched healthy women, and a follow-up study 72hr after the administration of intravenous iron (n = 16). Lipids, malondialdehyde, cholesteryl ester transfer protein (CETP), paraoxonase-1 (PON-1) and HDL chemical composition and functionality (cholesterol efflux and antioxidative activity) were measured. Cell cholesterol efflux from iron-deficient macrophages to a reference HDL was also evaluated.ResultsIDA patients showed higher triglycerides and CETP activity and lower HDL-C than controls (all p < 0.001). HDL particles from IDA patients showed higher triglyceride content (+30%,p < 0.05) and lower antioxidative capacity (−23%,p < 0.05). Although HDL-mediated cholesterol efflux was similar between the patients and controls, iron deficiency provoked a significant reduction in macrophage cholesterol efflux (−25%,p < 0.05). Arylesterase activity of PON-1 was significantly lower in IDA patients than controls (−16%,p < 0.05). The intravenous administration of iron was associated with a decrease in malondialdehyde levels and an increase in arylesterase activity of PON-1 (−22% and +18%, respectively, p < 0.05).ConclusionIDA is associated with oxidative stress and functionally deficient HDL particles. It remains to be determined if such alterations suffice to impair endothelial function in IDA. Fil: Meroño, Tomás. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina Fil: Dauteuille, Carolane. Université Pierre et Marie Curie; Francia. Inserm; Francia Fil: Tetzlaff, Walter Francisco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Martín, Maximiliano. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina Fil: Botta, Eliana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina Fil: Lhomme, Marie. Université Pierre et Marie Curie; Francia. Inserm; Francia Fil: Saez, María Soledad. Instituto Universitario del Hospital Italiano de Buenos Aires; Argentina Fil: Sorroche, Patricia Beatriz. Instituto Universitario del Hospital Italiano de Buenos Aires; Argentina Fil: Boero, Laura Estela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina Fil: Arbelbide, Jorge. Instituto Universitario del Hospital Italiano de Buenos Aires; Argentina Fil: Chapman, M. John. Inserm; Francia Fil: Kontush, Anatol. Inserm; Francia Fil: Brites, Fernando Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina

Background Plasma high-density lipoprotein cholesterol (HDL-C) levels are inversely associated with risk of coronary artery disease (CAD) in epidemiologic studies. Despite this, the directionality of this relationship and the underlying biology behind it remain to be firmly established, especially at the extremes of HDL-C levels. Objective We investigated differences in the HDL phosphosphingolipidome in a rare population of subjects with premature CAD despite high HDL-C levels to gain insight into the association between the HDL lipidome and CAD disease status in this unusual phenotype. We sought to assess differences in HDL composition that are associated with CAD in subjects with HDL-C >90th percentile. We predicted that quantitative lipidomic analysis of HDL particles would reveal novel differences between CAD patients and healthy subjects with matched HDL-C levels. Methods We collected plasma samples from 25 subjects with HDL-C >90th percentile and clinically manifest CAD and healthy controls with HDL-C >90th percentile and without self-reported CAD. More than 140 individual HDL phospholipid and sphingolipid species were analyzed by LC/MS/MS. Results Significant reductions in HDL phosphatidylcholine (−2.41%, Q value = 0.025) and phosphatidylinositol (−10.7%, Q value = 0.047) content, as well as elevated sphingomyelin (+10.0%, Q value = 0.025) content, and sphingomyelin/phosphatidylcholine ratio (+12.8%, P value = .005) were associated with CAD status in subjects with high HDL-C. Conclusions These differences may lay the groundwork for further analysis of the relationship between the HDL lipidome and disease states, as well as for the development of biomarkers of CAD status and HDL function.

OBJECTIVE: High-density lipoprotein (HDL) particles exert potent antiatherogenic activities, including antioxidative actions, which are relevant to attenuation of atherosclerosis progression. Such activities are enriched in small, dense HDL and can be compromised under conditions of chronic inflammation like rheumatoid arthritis (RA). However, structure-function relationships of HDL largely remain indeterminate. METHODS: The relationships between HDL structure and function were evaluated in normolipidemic patients with active RA (DAS28 > 3.2; n = 12) and in normolipidemic age-matched controls (n = 10). Small, dense HDL3b and 3c particles were isolated from plasma or serum by density gradient ultracentrifugation and their physicochemical characteristics, lipidome (by LC/MS/MS) and antioxidative function (as protection of normolipidemic LDL from free radical-induced oxidation) were evaluated. RESULTS: As expected, active RA patients featured significantly elevated plasma levels of high-sensitivity C-reactive protein (hsCRP; p < 0.001) and serum amyloid A (SAA; p < 0.01) relative to controls. Antioxidative activity and weight % chemical composition of small, dense HDL did not differ between RA patients and controls (p > 0.05), whereas HDL phosphosphingolipidome was significantly altered in RA. Subgroup analyses revealed that RA patients featuring high levels of inflammation (hsCRP>10 mg/l) possessed small, dense HDL with reduced antioxidative activities (p < 0.01). Furthermore, antioxidative activity of HDL was inversely correlated with plasma hsCRP (p < 0.01). CONCLUSIONS: These data revealed that (i) despite normolipidemic state, the lipidome of small, dense HDL was altered in RA and (ii) high levels of inflammation can be responsible for the functional deficiency of small, dense HDL in RA. Fil: Gomez Rosso, Leonardo Adrián. Inserm; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina Fil: Lhomme, Marie. Inserm; Francia. Universite Pierre et Marie Curie; Francia Fil: Meroño, Tomás. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Sorroche, Patricia Beatriz. Instituto Universidad Escuela de Medicina del Hospital Italiano; Argentina Fil: Catoggio, Luis. Instituto Universidad Escuela de Medicina del Hospital Italiano; Argentina Fil: Soriano, Enrique. Instituto Universidad Escuela de Medicina del Hospital Italiano; Argentina Fil: Saucedo, Carla. Instituto Universidad Escuela de Medicina del Hospital Italiano; Argentina Fil: Malah, Verónica. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina Fil: Dauteuille, Carolane. Inserm; Francia. Universite Pierre et Marie Curie; Francia Fil: Boero, Laura Estela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Lesnik, Philippe. Inserm; Francia. Universite Pierre et Marie Curie; Francia Fil: Robillard, Paul. Inserm; Francia. Universite Pierre et Marie Curie; Francia Fil: Chapman, M. John. Inserm; Francia. Universite Pierre et Marie Curie; Francia Fil: Brites, Fernando Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina Fil: Kontush, Anatol. Inserm; Francia. Universite Pierre et Marie Curie; Francia

Low plasma levels of high-density lipoprotein-cholesterol (HDL-C) are typical of acute myocardial infarction (MI) and predict risk of recurrent cardiovascular events. The potential relationships between modifications in the molecular composition and the functionality of HDL subpopulations in acute MI however remain indeterminate.ST segment elevation MI (STEMI) patients were recruited within 24h after diagnosis (n=16) and featured low HDL-C (-31%, p0.05) and acute-phase inflammation (determined as marked elevations in C-reactive protein, serum amyloid A (SAA) and interleukin-6) as compared to age- and sex-matched controls (n=10). STEMI plasma HDL and its subpopulations (HDL2b, 2a, 3a, 3b, 3c) displayed attenuated cholesterol efflux capacity from THP-1 cells (up to -32%, p0.01, on a unit phospholipid mass basis) vs.Plasma HDL and small, dense HDL3b and 3c subpopulations from STEMI patients exhibited reduced anti-oxidative activity (up to -68%, p0.05, on a unit HDL mass basis). HDL subpopulations in STEMI were enriched in two proinflammatory bioactive lipids, lysophosphatidylcholine (up to 3.0-fold, p0.05) and phosphatidic acid (up to 8.4-fold, p0.05), depleted in apolipoprotein A-I (up to -23%, p0.05) and enriched in SAA (up to +10.2-fold, p0.05); such changes were most marked in the HDL3b subfraction. In vitro HDL enrichment in both lysophosphatidylcholine and phosphatidic acid exerted deleterious effects on HDL functionality.In the early phase of STEMI, HDL particle subpopulations display marked, concomitant alterations in both lipidome and proteome which are implicated in impaired HDL functionality. Such modifications may act synergistically to confer novel deleterious biological activities to STEMI HDL.Our present data highlight complex changes in the molecular composition and functionality of HDL particle subpopulations in the acute phase of STEMI, and for the first time, reveal that concomitant modifications in both the lipidome and proteome contribute to functional deficiencies in cholesterol efflux and antioxidative activities of HDL particles. These findings may provide new biomarkers and new insights in therapeutic strategy to reduce cardiovascular risk in this clinical setting where such net deficiency in HDL function, multiplied by low circulating HDL concentrations, can be expected to contribute to accelerated atherogenesis.

The membrane protein Scavenger Receptor Class B, Type 1 (SR-BI), coded by the gene SCARB1, facilitates the selective uptake of cholesteryl esters from HDL in the liver. Its impact on human lipoprotein metabolism however is not fully understood. Our laboratory has recently identified two homozygotes and 16 heterozygotes for a coding mutation in SCARB1 (c.1127C>T, p.Pro376Leu). We assessed the hypothesis that this SCARB1 mutation significantly increases HDL-C and alters HDL composition and biological function. Plasma from subjects homozygous (n=2) or heterozygous (n=8) for the SR-BI Pro376Leu mutation was compared with that of normolipidemic controls. Five major HDL subfractions were isolated from EDTA-treated plasma using isopycnic density gradient ultracentrifugation and their chemical composition was assayed using commercial enzymatic assay kits. Quantification of >160 molecular species of HDL phospho- and sphingolipids was accomplished via a novel LC-ESI/MS/MS based analysis. Cholesterol efflux capacity, measured from THP-1 macrophages, was determined in total HDL. We identified a >2-fold increase in HDL-C in homozygotes and a >1.5-fold increase in heterozygotes compared to controls, owing mainly to an increase in large, light HDL2 particles. The ApoA-I/ApoA-II ratio was increased in a gene-dose dependent fashion. HDL isolated from heterozygotes mediated 13.5% less efflux when compared to particles from control subjects. Analysis of the HDL phosphosphingolipidome revealed a 23% decrease in phosphatidylinositol content between carriers and controls. A gene-dose dependent trend towards diminishment of phosphatidylserine and increased ceramide was noticeable. In conclusion, the SR-BI Pro376Leu significantly increases HDL levels, but potentially reduces the capacity of HDL to mediate cellular cholesterol efflux. This may be due in part to a decrease in minor, negatively charged phospholipid subclasses including PI and PS, which have previously been shown to play a functional role in stimulating cellular cholesterol efflux.

Plasma concentrations of HDL-C have long been shown to correlate inversely with risk of coronary artery disease (CAD), however the causal nature of this association has not been established. Here we examine the chemical composition and phosphoshingolipidome of HDL in a cohort of subjects with premature CAD, despite having HDL levels ≥90th percentile. We hypothesized that HDL from hyperalphalipoproteinemic subjects with CAD would have distinct compositional changes compared to healthy hyperalphalipoproteinemic subjects, which may relate a reduction in HDL functionality and a pro-atherogenic state. Subjects with HDL ≥90th percentile and CAD (HHDL+CAD, n=25) were compared to healthy subjects with HDL ≥90th percentile (HHDL, n=23). A group of healthy controls with HDL between the 25th and 75th percentile (n=11) was used as reference. HDL subfractions were isolated from EDTA plasma using isopycnic density gradient ultracentrifugation and their chemical composition was assayed using commercial enzymatic assay kits. Quantification of >160 molecular species of total HDL phospho- and sphingolipids was accomplished via a novel method using LC-ESI/MS/MS analysis. The most striking differences were observed in total HDL phospho- and sphingolipid subclasses between groups. When expressed as a percentage of total phosphosphingolipid, phosphatidylcholine (PC) and phosphatidylinositol (PI) were depleted in HHDL+CAD group compared to HHDL, while sphingomyelin (SM) was increased, resulting in a lower PC/SM ratio. The HDL PC/SM ratio has previously been shown to correlate with HDL surface fluidity and antioxidative activity. Additionally, enrichment of PI, a minor, negatively charged phospholipid, has been shown to stimulate cholesterol efflux to reconstituted HDL. Reduction in these two metrics, observed in the HHDL+CAD group, may indicate functionally deficient HDL and may represent pro-atherogenic, HDL-associated biomarkers of CAD in hyperalphalipoproteinemia.