The Effects of Atorvastatin Therapy on Rheological Characteristics of Erythrocyte Membrane, Serum Lipid Profile and Oxidative Status in Patients with Dyslipidemia

The statins, most commonly used in the treatment of hyperlipidemia, have certain beneficial effects including improved endothelial function, plaque stability and decreased oxidative stress and inflammation, beyond their lipid-lowering effect in plasma. We evaluated the pleiotropic impact of atorvastatin on erythrocyte structural/mechanical properties and lipid peroxidation in dyslipidemics. The study group included 44 patients with dyslipidemia and was divided into subgroups according to triglyceride and cholesterol levels as hypercholesterolemic (n?=?29) and mixed-type hyperlipidemic (n?=?15). Subjects were given 10?mg atorvastatin per day for 12?weeks. Changes in serum lipid composition, lipid contents, Na⁺/K⁺-ATPase activity and osmotic fragility in erythrocytes and oxidative stress parameters of erythrocytes and plasma were studied. Atorvastatin therapy improved the serum lipid profile of both subgroups. This alteration was accompanied by a decreased level of cholesterol in erythrocyte membranes. Moreover, enhanced activity of Na⁺/K⁺-ATPase in erythrocytes reflected the improvements in membrane lipids of both subgroups. However, a significant change was observed in osmotic fragility values of the mixed-typed dyslipidemic group. This treatment lowered the lipid peroxidation in plasma and erythrocytes and increased plasma total antioxidant capacity in all groups. The present study shows that the use of atorvastatin reversed the structural and functional features of erythrocyte membranes in dyslipidemic subjects. Also, hypolipidemic therapy had a beneficial impact on a balance between oxidant and antioxidant systems.     

Apple Cider Vinegar Modulates Serum Lipid Profile,Erythrocyte, Kidney,and Liver Membrane Oxidative Stress in Ovariectomized Mice Fed High Cholesterol

The purpose of this study was to investigate the potentially beneficial effects of apple cider vinegar (ACV) supplementation on serum triglycerides, total cholesterol, liver and kidney membrane lipid peroxidation, and antioxidant levels in ovariectomized (OVX) mice fed high cholesterol. Four groups of ten female mice were treated as follows: Group I received no treatment and was used as control. Group II was OVX mice. Group III received ACV intragastrically (0.6 % of feed), and group IV was OVX and was treated with ACV as described for group III. The treatment was continued for 28 days, during which the mice were fed a high-cholesterol diet. The lipid peroxidation levels in erythrocyte, liver and kidney, triglycerides, total, and VLDL cholesterol levels in serum were higher in the OVX group than in groups III and IV. The levels of vitamin E in liver, the kidney and erythrocyte glutathione peroxidase (GSH-Px), and erythrocyte-reduced glutathione (GSH) were decreased in group II. The GSH-Px, vitamin C, E, and β-carotene, and the erythrocyte GSH and GSH-Px values were higher in kidney of groups III and IV, but in liver the vitamin E and β-carotene concentrations were decreased. In conclusion, ACV induced a protective effect against erythrocyte, kidney, and liver oxidative injury, and lowered the serum lipid levels in mice fed high cholesterol, suggesting that it possesses oxidative stress scavenging effects, inhibits lipid peroxidation, and increases the levels of antioxidant enzymes and vitamin.     

钒对人红细胞膜蛋白和膜脂质过氧化的影响

对钒酸根V（V）与红细胞膜相互作用研究表明V（V）使膜蛋白内源荧光淬灭（KD,37＝2．23,KD,20＝4．17）和膜巯基含量降低,但对膜脂质过氧化影响较小,提示V（V）主要与膜蛋白作用．与V（V）不同,V（V）与红细胞膜的作用虽使膜蛋白就基含量下降,但不显著,其主要作用是引起膜脂质过氧化．     

Atherogenic Dyslipidemia in Children: Evaluation of Clinical,Biochemical and Genetic Aspects

The precursors of atherogenic dyslipidemia (AD) are not well defined. Therefore, we investigated 62 non-obese, non-diabetic AD and 221 normolipemic children. Anthropometric parameters, blood pressure and biochemical measures were obtained in index children, their parents and all available siblings. The heritability (h²) of anthropometric and biochemical traits was estimated by SOLAR. Rare and common variants in APOA1 and LPL genes were screened by re-sequencing. Compared to normolipemic, AD children showed increased body mass index, waist circumference, plasma glucose, insulin, ApoB, HOMA-IR, hs-CRP and lower adiponectin (p<0.001 for all). Metabolic syndrome was present in 40% of AD while absent in controls. All traits (except adiponectin and hs-CRP) showed a strong familial aggregation, with plasma glucose having the highest heritability (89%). Overall, 4 LPL loss-of-function mutations were detected (p.Asp9Asn, p.Ser45Asn, p.Asn291Ser, p.Leu365Val) and their cumulative prevalence was higher in AD than in control children (0.073 vs. 0.026; P=0.038). The LPL p.S447* gain-of-function mutation, resulted to be less frequent in AD than in control children (0.064 vs. 0.126; P=0.082). No variant in the APOA1 gene was found. Our data indicate that AD is a rather common dyslipidemia in childhood; it associates with metabolic abnormalities typical of insulin resistant state and shows a strong familial aggregation. LPL variants may contribute to the development of AD phenotype.     

Reactivity of Phospholipid Hydroperoxide Glutathione Peroxidase with Membrane and Lipoprotein Lipid Hydroperoxides

A comparative study has been carried out on the general reactivity of lipid hydroperoxides in liposornes, biological membranes and lipoproteins with two Se-dependent peroxidases: Glutathione Peroxidase (GPX) and Phospholipid Hydroperoxide Glutathione Peroxidase (PHGPX). While PHGPX reduces all hydroperoxides derived from phospholipids, cholesterol and cholesterol esters, GPX reduces only fatty acid hydroperoxides released after treatment of phospholipid hydroperoxides with phospholipase A,. These findings highlight the role of PHGPX in protecting biomembranes from peroxidative damage and add new insight into how cholesterol hydroperoxides are detossified in cells.     

Reactivity of Phospholipid Hydroperoxide Glutathione Peroxidase with Membrane and Lipoprotein Lipid Hydroperoxides

A comparative study has been carried out on the general reactivity of lipid hydroperoxides in liposornes, biological membranes and lipoproteins with two Se-dependent peroxidases: Glutathione Peroxidase (GPX) and Phospholipid Hydroperoxide Glutathione Peroxidase (PHGPX). While PHGPX reduces all hydroperoxides derived from phospholipids, cholesterol and cholesterol esters, GPX reduces only fatty acid hydroperoxides released after treatment of phospholipid hydroperoxides with phospholipase A,. These findings highlight the role of PHGPX in protecting biomembranes from peroxidative damage and add new insight into how cholesterol hydroperoxides are detossified in cells.     

从人和动物血浆及红细胞膜脂肪酸谱探讨脂质代谢实验模型动物选取

目的比较大鼠、家兔和人血浆及红细胞膜脂肪酸谱的异同,为脂质代谢模型动物的选取提供可靠依据。方法采用氯仿-甲醇快速提取大鼠、家兔和人血浆及细胞膜中的脂肪,并用碱法甲基化,经薄层层析纯化的甲基酯用100 mm×0.25 mm气相色谱毛细管柱测定脂肪酸组成。结果血浆中总MUFA、9c18：1、9c12c18：2 n-6和α-18：3 n-3等脂肪酸含量较高;而红细胞膜中总PUFA、AA、22：4n-6、DPA和DHA等脂肪酸含量较高;人和大鼠16：0、18：0、18：1、α-18：3n-3、AA、EPA、DHA、MUFA、n-3PUFA和n-6/n-3值均较为接近,但和家兔存在显著差异。结论与家兔相比,大鼠和人血浆及红细胞膜脂肪酸谱较接近,因此,在选取脂质代谢实验动物时,应优先考虑大鼠为模型动物,以得到与人体实际更接近的结果。     

Effect of Sesamin on Cholesterol Synthesis and on the Distribution of Incorporated Linoleic Acid in Lipid Subfractions in Cultured Rat Cells

Since sesamin influences the metabolism of essential fatty acids, its effects on cholesterol metabolism and on the incorporation of linoleic acid were studied by using cultured rat artery smooth muscle cells (SMCs) and primary cultured rat hepatocytes. Cholesterol synthesis from acetate was inhibited by sesamin in SMCs, and the distribution of incorporated linoleic acid in the lipid and phospholipid subfractions was altered by sesamin in rat hepatocytes.     

Erythrocyte Membrane Model with Explicit Description of the Lipid Bilayer and the Spectrin Network

The membrane of the red blood cell (RBC) consists of spectrin tetramers connected at actin junctional complexes, forming a two-dimensional (2D) sixfold triangular network anchored to the lipid bilayer. Better understanding of the erythrocyte mechanics in hereditary blood disorders such as spherocytosis, elliptocytosis, and especially, sickle cell disease requires the development of a detailed membrane model. In this study, we introduce a mesoscale implicit-solvent coarse-grained molecular dynamics (CGMD) model of the erythrocyte membrane that explicitly describes the phospholipid bilayer and the cytoskeleton, by extending a previously developed two-component RBC membrane model. We show that the proposed model represents RBC membrane with the appropriate bending stiffness and shear modulus. The timescale and self-consistency of the model are established by comparing our results with experimentally measured viscosity and thermal fluctuations of the RBC membrane. Furthermore, we measure the pressure exerted by the cytoskeleton on the lipid bilayer. We find that defects at the anchoring points of the cytoskeleton to the lipid bilayer (as in spherocytes) cause a reduction in the pressure compared with an intact membrane, whereas defects in the dimer-dimer association of a spectrin filament (as in elliptocytes) cause an even larger decrease in the pressure. We conjecture that this finding may explain why the experimentally measured diffusion coefficients of band-3 proteins are higher in elliptocytes than in spherocytes, and higher than in normal RBCs. Finally, we study the effects that possible attractive forces between the spectrin filaments and the lipid bilayer have on the pressure applied on the lipid bilayer by the filaments. We discover that the attractive forces cause an increase in the pressure as they diminish the effect of membrane protein defects. As this finding contradicts with experimental results, we conclude that the attractive forces are moderate and do not impose a complete attachment of the filaments to the lipid bilayer.     

克山病病区粮喂养大鼠红细胞膜脂流动性的变化

本文观察了低硒的克山病病区粮和克山病病区粮补硒后喂养大鼠对其红细胞膜脂流动性的影响。实验结果表明克山病病区粮喂养的大鼠红细胞膜脂流动性较正常对照降低,其原因可能与机体处于低硒状态下红细胞膜结合硒含量降低、红细胞膜胆固醇含量及脂质过氧化产物升高有关,克山病病区粮补硒后喂养大鼠,其红细胞膜脂流动性恢复至正常对照。     

Erythrocyte Membrane Model with Explicit Description of the Lipid Bilayer and the Spectrin Network

The membrane of the red blood cell (RBC) consists of spectrin tetramers connected at actin junctional complexes, forming a two-dimensional (2D) sixfold triangular network anchored to the lipid bilayer. Better understanding of the erythrocyte mechanics in hereditary blood disorders such as spherocytosis, elliptocytosis, and especially, sickle cell disease requires the development of a detailed membrane model. In this study, we introduce a mesoscale implicit-solvent coarse-grained molecular dynamics (CGMD) model of the erythrocyte membrane that explicitly describes the phospholipid bilayer and the cytoskeleton, by extending a previously developed two-component RBC membrane model. We show that the proposed model represents RBC membrane with the appropriate bending stiffness and shear modulus. The timescale and self-consistency of the model are established by comparing our results with experimentally measured viscosity and thermal fluctuations of the RBC membrane. Furthermore, we measure the pressure exerted by the cytoskeleton on the lipid bilayer. We find that defects at the anchoring points of the cytoskeleton to the lipid bilayer (as in spherocytes) cause a reduction in the pressure compared with an intact membrane, whereas defects in the dimer-dimer association of a spectrin filament (as in elliptocytes) cause an even larger decrease in the pressure. We conjecture that this finding may explain why the experimentally measured diffusion coefficients of band-3 proteins are higher in elliptocytes than in spherocytes, and higher than in normal RBCs. Finally, we study the effects that possible attractive forces between the spectrin filaments and the lipid bilayer have on the pressure applied on the lipid bilayer by the filaments. We discover that the attractive forces cause an increase in the pressure as they diminish the effect of membrane protein defects. As this finding contradicts with experimental results, we conclude that the attractive forces are moderate and do not impose a complete attachment of the filaments to the lipid bilayer.     

Localization of Cholesterol and Fatty Acid in a Model Lipid Membrane: A Neutron Diffraction Approach

The intercellular lipid matrix of the skin’s stratum corneum serves to protect the body against desiccation and simultaneously limits the passage of drugs and other xenobiotics into the body. The matrix is made up of ceramides, free fatty acids, and cholesterol, which are organized as two coexisting crystalline lamellar phases. In studies reported here, we sought to use the technique of neutron diffraction, together with the device of isotopic (H/D) substitution, to determine the molecular architecture of the lamellar phase having a repeat distance of 53.9 ± 0.3 Å. Using hydrogenous samples as well as samples incorporating perdeuterated (C24:0) fatty acids and selectively deuterated cholesterol, the diffraction data obtained were used to construct neutron scattering length density profiles. By this means, the locations within the unit cell were determined for the cholesterol and fatty acids. The cholesterol headgroup was found to lie slightly inward from the unit cell boundary and the tail of the molecule located 6.2 ± 0.2 Å from the unit cell center. The fatty acid headgroups were located at the unit cell boundary with their acyl chains straddling the unit cell center. Based on these results, a molecular model is proposed for the arrangement of the lipids within the unit cell.     

Localization of Cholesterol and Fatty Acid in a Model Lipid Membrane: A?Neutron Diffraction Approach

The intercellular lipid matrix of the skin’s stratum corneum serves to protect the body against desiccation and simultaneously limits the passage of drugs and other xenobiotics into the body. The matrix is made up of ceramides, free fatty acids, and cholesterol, which are organized as two coexisting crystalline lamellar phases. In studies reported here, we sought to use the technique of neutron diffraction, together with the device of isotopic (H/D) substitution, to determine the molecular architecture of the lamellar phase having a repeat distance of 53.9 ± 0.3 Å. Using hydrogenous samples as well as samples incorporating perdeuterated (C24:0) fatty acids and selectively deuterated cholesterol, the diffraction data obtained were used to construct neutron scattering length density profiles. By this means, the locations within the unit cell were determined for the cholesterol and fatty acids. The cholesterol headgroup was found to lie slightly inward from the unit cell boundary and the tail of the molecule located 6.2 ± 0.2 Å from the unit cell center. The fatty acid headgroups were located at the unit cell boundary with their acyl chains straddling the unit cell center. Based on these results, a molecular model is proposed for the arrangement of the lipids within the unit cell.     

High-cholesterol Diets Induce Changes in Lipid Composition of Rat Erythrocyte Membrane Including Decrease in Cholesterol,Increase in α-Tocopherol and Changes in Fatty Acids of Phospholipids

Effects of high dietary cholesterol on erythrocyte membrane lipids were studied. Feeding rats with a diet containing 0.5% cholesterol and 0.15% sodium cholate for two weeks induced changes in erythrocyte membrane lipids including a decrease in cholesterol, an increase in α-tocopherol (α-Toc) and changes in the fatty acid composition of phospholipids. Oleic acid and linoleic acid increased, while arachidonic acid decreased in phosphatidylcholine. Saturated fatty acids decreased and unsaturated fatty acids increased in phosphatidylethanolamine. Almost the same changes in membrane lipids were also noted after six weeks of feeding rats with the diet. A diet containing 0.5% cholesterol but without sodium cholate caused a decrease in erythrocyte cholesterol and an increase in erythrocyte α-Toc after two weeks of feeding, as compared to the basal diet, indicating that high dietary cholesterol, but not sodium cholate, was responsible for these changes in the erythrocyte membrane.     

Acute Coronary Syndrome Remodels the Protein Cargo and Functions of High-Density Lipoprotein Subfractions

Objectives

This study examined alterations in the functions and proteome of high-density lipoprotein (HDL) subfractions (HDL2 and HDL3) isolated from patients with acute coronary syndrome (ACS) compared with control subjects.

Methods

We measured HDL subfraction cholesterol efflux capacity, inflammatory index (HII), paraoxonase-1 (PON1) activity, and lipid hydroperoxide (LOOH) levels in both male age-matched controls and the ACS group (n = 40/group). Additionally, proteomic analysis was used to monitor changes in the HDL subfraction proteome between controls and ACS subjects.

Results

Both HDL2 and HDL3 from ACS patients had greater HII and LOOH levels compared with controls (P<0.001); PON1 activity and cholesterol efflux capacity in both HDL2 and HDL3 from the ACS group were significantly less than those of controls (P<0.001). Using proteomic analysis, we demonstrated that, compared with the control group, nine proteins were selectively enriched in HDL3 from subjects with ACS, and ras-related protein Rab-7b was decreased in HDL3. Additionally, in the ACS subjects, 12 proteins were decreased in HDL2 and 4 proteins were increased in HDL2.

Conclusions

Functional HDL subfractions shifted to dysfunctional HDL subfractions during ACS, and the functional impairment was linked to remodeled protein cargo in HDL subfractions from ACS patients.     

Contemporary Management and Attainment of Cholesterol Targets for Patients with Dyslipidemia in China

Aims

It is well-established that lipid disorder is an important cardiovascular risk factor, and failure to reach optimal lipid levels significantly contributes to the residual cardiovascular risks. However, limited information is available on the management and the attainment of recommended cholesterol targets in real-world practice in China.

Methods and Results

A nationally representative sample of 12,040 patients with dyslipidemia from 19 provinces and 84 hospitals across China were consecutively enrolled in this survey. Risk stratification and individual cholesterol target was established for all participants. This survey identified a high-risk cohort, with over 50% of patients had hypertension, 37.5% had coronary artery disease, and more than 30% had peripheral artery disease. Thirty-nine percent of all participants received lipid lowering medications. And the majority of them (94.5%) had statins (42.5% with atorvastatin, 29.0% with simvastatin, and 15.2% with rosuvastatin). However, the overall attainment for low-density lipoprotein cholesterol (LDL-C) target is low (25.8%), especially, in female (22.2%), and in patients with increased body mass index (BMI) (38.3% for BMI<18.5, 28.1% for BMI 18.5–24.9, 26.0% for BMI 25.0–29.9, and 17.4% for BMI≥30, P<0.0001). Subgroup analysis also showed the attainment is significantly lower in patients who were stratified into high (19.9%) and very high (21.1%) risk category. In logistic regression analysis, eight factors (BMI, gender, coronary artery disease, systolic and diastolic blood pressure, hypertension, family history of premature coronary artery disease and current smoking) were identified as independent predictors of LDL-C attainment.

Conclusions

Despite the proven benefits of lipid-lowering therapies, current management of dyslipidemia continues to be unsatisfied. A considerable proportion of patients failed to achieve guideline-recommended targets in China, and this apparent treatment gap was more pronounced among patients with increased BMI, higher risk stratification and women.     

Mitochondrial GWA Analysis of Lipid Profile Identifies Genetic Variants to Be Associated with HDL Cholesterol and Triglyceride Levels

It has been suggested that mitochondrial dysfunction has an influence on lipid metabolism. The fact that mitochondrial defects can be accumulated over time as a normal part of aging may explain why cholesterol levels often are altered with age. To test the hypothesis whether mitochondrial variants are associated with lipid profile (total cholesterol, LDL, HDL, and triglycerides) we analyzed a total number of 978 mitochondrial single nucleotide polymorphisms (mtSNPs) in a sample of 2,815 individuals participating in the population-based KORA F4 study. To assess mtSNP association while taking the presence of heteroplasmy into account we used the raw signal intensity values measured on the microarray and applied linear regression. Ten mtSNPs (mt3285, mt3336, mt5285, mt6591, mt6671, mt9163, mt13855, mt13958, mt14000, and mt14580) were significantly associated with HDL cholesterol and one mtSNP (mt15074) with triglycerides levels. These results highlight the importance of the mitochondrial genome among the factors that contribute to the regulation of lipid levels. Focusing on mitochondrial variants may lead to further insights regarding the underlying physiological mechanisms, or even to the development of innovative treatments. Since this is the first mitochondrial genome-wide association analysis (mtGWAS) for lipid profile, further analyses are needed to follow up on the present findings.