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Partially hydrogenated oils (PHO) have been removed from the food supply due to adverse effects on risk for coronary heart disease (CHD). High‐oleic soybean oils (HOSBO) are alternatives that provide functionality for different food applications. The objective of this study was to determine how consumption of diets containing HOSBO compared to other alternative oils, with similar functional properties, modifies LDL cholesterol (LDLc) and other risk factors and biomarkers of CHD. A triple‐blind, crossover, randomized controlled trial was conducted in humans (n = 60) with four highly‐controlled diets containing (1) HOSBO, (2) 80:20 blend of HOSBO and fully hydrogenated soybean oil (HOSBO+FHSBO), (3) soybean oil (SBO), and (4) 50:50 blend of palm oil and palm kernel oil (PO + PKO). Before and after 29 days of feeding, lipids/lipoproteins, blood pressure, body composition, and markers of inflammation, oxidation, and hemostasis were measured. LDLc, apolipoprotein B (apoB), NonHDL‐cholesterol (HDLc), ratios of total cholesterol (TC)‐to‐HDLc and LDLc‐to‐HDL cholesterol, and LDL particle number and small LDL particles concentration were lower after HOSBO and HOSBO+FHSBO compared to PO (specific comparisons p

The phospholipid composition of lipoproteins is determined by the specificity of hepatic phospholipid biosynthesis. Plasma phospholipid 20:4n‐6 and 22:6n‐3 concentrations are higher in women than in men. We used this sex difference in a lipidomics analysis of the impact of endocrine factors on the phospholipid class and molecular species composition of fasting plasma from young men and women. Diester species predominated in all lipid classes measured. 20/54 Phosphatidylcholine (PtdCho) species were alkyl ester, 15/48 phosphatidylethanolamine (PtdEtn) species were alkyl ester, and 12/48 PtdEtn species were alkenyl ester. There were no significant differences between sexes in the proportions of alkyl PtdCho species. The proportion of alkyl ester PtdEtn species was greater in women than men, while the proportion of alkenyl ester PtdEtn species was greater in men than women. None of the phosphatidylinositol (PtdIns) or phosphatidylserine (PtdSer) molecular species contained ether‐linked fatty acids. The proportion of PtdCho16:0_22:6, and the proportions of PtdEtn O‐16:0_20:4 and PtdEtn O‐18:2_20:4 were greater in women than men. There were no sex differences in PtdIns and PtdSer molecular species compositions. These findings show that plasma phospholipids can be modified by sex. Such differences in lipoprotein phospholipid composition could contribute to sexual dimorphism in patterns of health and disease.

Elevated postprandial triacylglycerols (TAG) are an important risk factor for cardiovascular disease. Men have higher plasma TAG and impaired TAG clearance compared to women, which may contribute to sex differences in risk of cardiovascular disease. Understanding mechanisms of sex differences in TAG metabolism may yield novel therapeutic targets to prevent cardiovascular disease. Cholesteryl ester transfer protein (CETP) is a lipid shuttling protein known for its effects on high‐density lipoprotein (HDL) cholesterol levels. Although mice lack CETP, we previously demonstrated that transgenic CETP expression in female mice alters TAG metabolism. The impact of CETP on TAG metabolism in males, however, is not well understood. Here, we demonstrate that CETP expression increases plasma TAG in males, especially in very‐low density lipoprotein (VLDL), by impairing postprandial plasma TAG clearance compared to wild‐type (WT) males. Gonadal hormones were required for CETP to impair TAG clearance, suggesting a role for sex hormones for this effect. Testosterone replacement in the setting of gonadectomy was sufficient to restore the effect of CETP on TAG. Lastly, liver androgen receptor (AR) was required for CETP to increase plasma TAG. Thus, expression of CETP in males raises plasma TAG by impairing TAG clearance via testosterone signaling to AR. Further understanding of how CETP and androgen signaling impair TAG clearance may lead to novel approaches to reduce TAG and mitigate risk of cardiovascular disease.

Oxidized low-density lipoprotein (Ox-LDL) may induce apoptosis and dysfunction of vascular endothelial cells, contributing to the initiation and development of atherosclerosis and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) plays a central role in Ox-LDL uptake in the course of atherogenesis. Humanin (HN), a mitochondrial-derived peptide, was recently demonstrated to exert a protective role against endothelial dysfunction and Ox-LDL-induced progression of atherosclerosis. The HN analog HNGF6A (HNG) modulates cholesterol metabolism in macrophage RAW 264.7 cells. However, whether HNG affects Ox-LDL metabolism in endothelial cells is unknown. In this study, we investigated the effect of HNG on Ox-LDL accumulation in human umbilical vein endothelial cell (HUVEC) and its underlying mechanisms. HUVEC were preincubated with HNG for 1 h before addition of Ox-LDL. Total cholesterol content was measured by using a tissue total cholesterol assay kit and flow cytometry. Cell viability was measured by CCK8 assay. Protein content was examined by Western blot assays. Flow cytometry was used to identify apoptotic cells. Flow cytometry and tissue total cholesterol assays showed that HNG reduced Ox-LDL accumulation in HUVEC. In addition, HNG inhibited Ox-LDL-induced apoptosis of HUVEC. Western blot results showed that HNG reduced LOX-1 protein content. However, when LOX-1 was knocked down or inhibited, the effect of HNG in reducing Ox-LDL aggregation and apoptosis in HUVEC disappeared. Our study demonstrated that HNG reduces lipid aggregation and apoptosis in HUVEC in a LOX-1-dependent manner.

VASPIN, visceral adipose tissue-derived serpin, is an adipokine ameliorating insulin resistance in obesity. Here, we investigated the role of VASPIN and its genetic variants in lipid metabolism. We measured serum VASPIN concentrations by ELISA in 823 metabolically well-characterized Caucasian subjects (Sorbs from Germany). Furthermore, we genotyped 30 representative single nucleotide polymorphisms (SNP) in two independent cohorts with metabolic phenotyping, the Sorbs (N = 823) and Leipzig (N = 919), and conducted genotype-phenotype association analyses. Circulating VASPIN strongly correlated with triacylglycerol levels (TAG; p = 1.079 × 10-11 ), and moderately with apolipoprotein A1 and low-density lipoprotein cholesterol (p = 0.026). Genetic variants in VASPIN were nominally associated with cholesterol, high-density and low-density lipoprotein (HDL-chol, LDL-chol), lipoprotein A, and apolipoprotein B as well as with TAG and free fatty acids (all p < 0.05 adjusted for age, sex, and body mass index [BMI]). Mendelian randomization analysis using VASPIN SNP as an instrumental variable showed borderline influence of VASPIN on LDL-chol levels (p = 0.05). Associations of VASPIN and its genetic variation with metabolic traits suggest a role of VASPIN in human lipid metabolism.

The triacylglycerol (TAG)-lowering effects of long-chain n-3 fatty acids, and in particular docosahexaenoic acid (DHA), are well documented, although these effects manifest large interindividual variability. The objective of this secondary analysis is to investigate whether common single-nucleotide polymorphisms (SNP) in genes involved in DHA synthesis and TAG metabolism are associated with the responsiveness of blood lipids, lipoprotein, and apolipoprotein concentration to dietary treatment by DHA supplied in high-oleic canola oil (HOCO). In a randomized, crossover-controlled feeding trial, 129 subjects with metabolic syndrome received high-oleic canola oil (HOCO) and high-oleic canola oil supplemented with DHA (HOCO-DHA), each for 4 weeks. During the HOCO-DHA phase, the intake of DHA ranged from 1 to 2.5 g/day. The subjects were genotyped for apolipoprotein E (APOE) isoforms, and SNP including FADS1-rs174561, FADS2-rs174583, ELOVL2-rs953413, ELOVL5-rs2397142, CETP-rs5882, SCD1-rs2234970, PPARA-rs6008259, and LIPF-rs814628 were selected as important genes controlling fatty acid metabolism. Overall, consumption of HOCO-DHA oil reduced blood concentrations of TAG by 24% compared to HOCO oil. The reduction in TAG was independent of genetic variations in the studied genes. Similarly, no treatment-by-gene interactions were evident in the response to other lipids, lipoproteins, or apolipoproteins to DHA supplementation. Nevertheless, a lower interindividual variation in the TAG response to DHA supplementation compared to other studies was observed in this analysis. The TAG-lowering effect of a supplemental body-weight-based dose of DHA was not influenced by genetic variations in APOE, FADS1, FADS2, ELOVL2, ELOVL5, CETP, SCD1, PPARA, and LIPF.

Although phytosterols, plant-derived sterol-like components, are well known for their cholesterol-lowering properties, their atherogenic potential is still under debate. Although they are known to share structural similarities with cholesterol, it is unclear whether their oxidized forms (oxyphytosterols) have the capacity to mediate proinflammatory responses in macrophages. In the present study, bone marrow-derived macrophages were treated with oxidized low-density lipoproteins, oxyphytosterols (7keto-sito/campesterol [7keto-sit/camp] or 7-beta-hydroxy-sito/campesterol [7OH-sit/camp]), nonoxidized phytosterol (-sitosterol), or carrier-control (cyclodextrin) in a dose- and time-dependent manner. Inflammatory cytokine release, activity, and the corresponding mRNA expression levels were analyzed. 7OH-sit/camp, rather than 7keto-sit/camp, induced a modest proinflammatory response in wild-type cells derived from C57Bl/6 mice. The observed mild inflammatory effects are independent of the low-density lipoprotein receptor and Cluster of differentiation 36/Scavenger receptor-a. These data suggest that exogenously added oxyphytosterols do not affect macrophage-mediated inflammatory responses, at least in vitro.

We evaluated whether CETP and LCAT gene polymorphisms are statistically associated with the high-density lipoprotein (HDL) size distribution, the cholesterol level of HDL subclasses, and the acute coronary syndrome (ACS) susceptibility. Two CETP gene polymorphisms (rs4783961 and rs708272) and one LCAT polymorphism (rs2292318) were genotyped by 5' exonuclease TaqMan assays in 619 patients with ACS and 607 control individuals. For HDL analysis, a subgroup of 100 healthy individuals was recruited; the HDL subclasses were separated via ultracentrifugation and polyacrylamide gradient gel electrophoresis under native conditions. Under a dominant model, the G allele of the rs708272 polymorphism was associated with an increased risk of ACS (odds ratios [OR] = 1.45, corrected p-value [pCDom ] = 0.036). The linkage disequilibrium analysis showed that one of the eight possible combinations was associated with the risk of developing ACS (OR = 1.52, pC = 0.02), which suggests that it may contribute to coronary atherosclerosis. The rs708272 G allele carriers had a lower concentration of cholesterol associated with the HDL2a and HDL3a subclasses when compared with subjects carrying the A allele. Carriers of LCAT rs2292318 A allele showed a lower concentration of high-density lipoprotein-cholesterol (HDL-C) in comparison to the GG genotype; the cholesterol associated with the each one of the five HDL subclasses was significantly lower in rs2292318 A than in GG subjects. In summary, this study demonstrates that the rs708272 polymorphism is associated with a heightened risk of developing ACS. In addition, we report the association of the rs708272 and rs2292318 polymorphisms with HDL-C levels and HDL subclasses.

The distinct effects of the estrogen and progestin components of hormonal therapy on the metabolism of apolipoprotein (apo) B-containing lipoproteins have not been studied. We enrolled eight healthy postmenopausal women in a placebo-controlled, randomized, double-blind crossover study. Each subject received placebo, conjugated equine estrogen (CEE, 0.625 mg/day) and CEE plus medroxyprogesterone acetate (MPA, 2.5 mg/day) for 8 weeks in a randomized order, with a 4-week washout between phases. Main outcomes were the fractional catabolic rate (FCR) and production rate (PR) of apo B100 in triglyceride-rich lipoproteins (TRL), intermediate-density lipoproteins (IDL) and low -density lipoprotein (LDL) and of apo B48 in TRL. Compared to placebo, CEE increased TRL apo B100 PR (p = 0.04). CEE also increased LDL apo B100 FCR (p = 0.02), but this effect was offset by a significant increase in LDL apo B100 PR (p = 0.04). Adding MPA to CEE negated the CEE effects resulting in no significant changes in TRL apo B100 PR and LDL apo B100 FCR and PR relative to placebo. Relative to placebo, during CEE there was a trend toward a reduction in plasma apo B48 concentrations and PR (p = 0.07 and p = 0.12, respectively). Compared with CEE, CEE + MPA significantly increased TRL apo B48 FCR (p = 0.02) as well as apo B48 PR (p = 0.01), resulting in no significant changes in apo B48 concentration. Estrogen and progestin have independent and opposing effects on the metabolism of the atherogenic apo B100- and apo B48-containing lipoproteins.

This study was carried out to determine the effects of flaxseed oil administration on gene expression levels related to insulin, lipid and inflammation in overweight diabetic patients with coronary heart disease (CHD). This randomized double-blind, placebo-controlled trial was conducted among 60 diabetic patients with CHD. Subjects were randomly allocated into two groups to intake either 1000 mg n-3 fatty acid from flaxseed oil containing 400 mg α-Linolenic acid [ALA (18:3n-3)] (n = 30) or placebo (n = 30) twice a day for 12 weeks. Gene expression related to insulin, lipid and inflammation were quantified in peripheral blood mononuclear cells (PBMC) of diabetic patients with CHD with RT-PCR method. Results of RT-PCR demonstrated that after the 12-week intervention, compared with the placebo, flaxseed oil supplementation could up-regulate gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.02) in PBMC of diabetic patients with CHD. In addition, compared with the placebo, taking flaxseed oil supplements down-regulated gene expression levels of lipoprotein(a) [LP(a)] (P = 0.001), interleukin-1 (IL-1) (P = 0.001) and tumor necrosis factor alpha (TNF-α) (P = 0.02) in PBMC of diabetic patients with CHD. We did not observe any significant effect of flaxseed oil supplementation on gene expression levels of low-density lipoprotein receptor (LDLR), IL-8 and transforming growth factor beta (TGF-β) in PBMC of diabetic patients with CHD. Overall, flaxseed oil supplementation for 12 weeks in diabetic patients with CHD significantly improved gene expression levels of PPAR-γ, LP(a), IL-1 and TNF-α, but did not influence LDLR, IL-8 and TGF-β.

Macrophage lipoprotein lipase (LPL) induces lipid accumulation and promotes atherosclerosis. However, the effects of lipoprotein hydrolysis products generated by LPL on macrophage-derived foam cell formation are not clearly understood. Thus, we analyzed the transcriptomic response to hydrolysis products via microarray analyses on RNA isolated from human THP-1 macrophages incubated with total lipoprotein hydrolysis products generated by LPL. The expression of 183 transcripts was significantly upregulated and 133 transcripts were significantly downregulated. Bioinformatics analyses revealed that there was a significant over-representation of genes involved in cell cycling, stress response, type I interferon signaling, cellular metal ion homeostasis, sterol metabolism, and nuclease activity. Interestingly, transcripts for 63 small nucleolar RNA were significantly upregulated. We verified the microarray data by quantitative real-time PCR and found that the expression of SNORA56, as well as the expression of genes associated with the cell cycle (PCNA and DKC1 variant 3), stress response (ATF3), type I interferon signaling (IFITM1), and lipid metabolism (CD36 and PLIN2) were significantly affected by LPL hydrolysis products. To determine if the free fatty acid (FFA) component of total lipoprotein hydrolysis products is sufficient to alter the expression of these genes, THP-1 macrophages were also incubated with the total FFA or individual classes of the FFA component. The gene regulation by the FFA component did not mimic that of the hydrolysis products, suggesting that the regulation of gene expression in THP-1 macrophages depends on the specific combination and concentration of lipid species present in the hydrolysis products, and not solely on FFA.

Lipoprotein (a) [Lp(a)] is an independent risk factor for cardiovascular disease. There are currently limited therapeutic options to lower Lp(a) levels. l-Carnitine has been reported to reduce Lp(a) levels. The aim of this study was to compare the effect of l-carnitine/simvastatin co-administration with that of simvastatin monotherapy on Lp(a) levels in subjects with mixed hyperlipidemia and elevated Lp(a) concentration. Subjects with levels of low-density lipoprotein cholesterol (LDL-C) >160 mg/dL, triacylglycerol (TAG) >150 mg/dL and Lp(a) >20 mg/dL were included in this study. Subjects were randomly allocated to receive l-carnitine 2 g/day plus simvastatin 20 mg/day (N = 29) or placebo plus simvastatin 20 mg/day (N = 29) for a total of 12 weeks. Lp(a) was significantly reduced in the l-carnitine/simvastatin group [−19.4%, from 52 (20–171) to 42 (15–102) mg/dL; p = 0.01], but not in the placebo/simvastatin group [−6.7%, from 56 (26–108) to 52 (27–93) mg/dL, p = NS versus baseline and p = 0.016 for the comparison between groups]. Similar significant reductions in total cholesterol, LDL-C, apolipoprotein (apo) B and TAG were observed in both groups. Co-administration of l-carnitine with simvastatin was associated with a significant, albeit modest, reduction in Lp(a) compared with simvastatin monotherapy in subjects with mixed hyperlipidemia and elevated baseline Lp(a) levels.

Previously, we found that Celastrus orbiculatus Thunb. (COT) decreases athero-susceptibility in lipoproteins and the aorta of guinea pigs fed a high-fat diet, and increases high-density lipoprotein (HDL). In the present study, we investigated the effect of COT in reducing lipid accumulation and promoting reverse cholesterol transport (RCT) in vivo and vitro. Healthy male mice were treated with high-fat diet alone, high-fat diet with COT (10.0 g/kg/d), or general fodder for 6 weeks. Serum levels of total cholesterol (TC), triglyceride (TG), HDL-C, non-HDL-C, and (3)H-cholesterol in plasma, liver, bile, and feces were determined. Pathological changes and the levels of TC and TG in liver were examined. The expression of hepatic genes and protein associated with RCT were analyzed. COT administration reduced lipid accumulation in the liver, ameliorated the pathological changes, and lessened liver injury, the levels of TG, TC, and non-HDL-C in plasma were decreased significantly, and COT led to a significant increase in plasma HDL-C and apolipoprotein A (apoA1). (3)H-cholesterol in plasma, liver, bile, and feces was also significantly increased in COT-treated mice compared to controls. Both mRNA and protein expression of SRB1, CYP7A1, LDLR, ATP-binding cassette transporters ABCA1, ABCG5, and LXRα were improved in COT-treated mice. An in vitro isotope tracing experiment showed that COT and its bioactive ingredients, such as celastrol, ursolic acid, oleanolic acid, and quercetin, significantly increased the efflux of (3)H-cholesterol. They also increased the expression of SRB1, ABCA1, and ABCG1 significantly in macrophages. Our findings provided a positive role of COT in reducing lipid accumulation by promoting RCT. These effects may be achieved by activating the SRB1 and ABC transporter pathway and promoting cholesterol metabolism via the CYP7A1 pathway in vivo. The effective ingredients in vitro are celastrol, ursolic acid, oleanolic acid, and quercetin.

The polyphenol-rich pomegranate juice (PJ) and the high-density lipoprotein (HDL)-associated paraoxonase1 (PON1) are known as potent atheroprotective antioxidants, but their effects on other tissues related to cardiovascular disease (CVD) remain unknown. The current study aimed to investigate the effects of treating mice with PJ or recombinant PON1 (rePON1) on the oxidation and lipid status of CVD-related tissues: serum, aorta, heart, liver, kidney, visceral, and subcutaneous adipose tissues (VAT and SAT). Both PJ consumption and rePON1 injection decreased the serum levels of thiobarbituric acid-reactive substances (16% and 19%) and triacylglycerols (TAG, 24% and 27%), while only rePON1 increased the levels of thiol groups (35%) and decreased serum cholesterol (15%). Both PJ and rePON1 significantly decreased aortic cholesterol (38% and 32%) and TAG (62% and 58%) contents in association with downregulation of the key TAG biosynthetic enzyme diacylglycerol O-acyltransferase 1 (DGAT1, 71% and 65%), while only PJ decreased aortic lipid peroxides (47%). Substantial TAG-lowering effects of both PJ and rePON1 were observed also in the heart (31% and 42%), liver (34% and 42%), and kidney (42% and 57%). In both VAT and SAT, rePON1 decreased the levels of lipid peroxides (28% and 25%), while PJ decreased the TAG content (22% and 18%). Ex vivo incubation of SAT with serum derived from mice that consumed PJ or injected with rePON1 decreased SAT lipid peroxides (35% or 28%) and TAG mass (12% or 10%). These novel findings highlight potent TAG-lowering properties of exogenous (PJ) and endogenous (PON1) antioxidants in tissues associated with CVD.

The heterogeneity and content of human plasma high-density lipoprotein (HDL) related to their atheroprotective properties determined by various molecular and cellular mechanisms still remain to be completely clarified. For 29 atherosclerosis-free male subjects, we studied the relationship of plasma lipid levels and the content of apolipoprotein A-I (apoA-I)-containing HDL with preβ-electrophoretic mobility, the efficiency of BODIPY-cholesterol efflux from RAW 264.7 macrophages to apolipoprotein B (apoB)-deficient plasma, and the expression level of 22 genes related to HDL metabolism in mononuclear cells. A significant decrease in the absolute content of apoA-I in preβ-HDL was found in subjects with hypoalphalipoproteinemia compared with the subjects with hyperalphalipoproteinemia. The preβ-to-α-ratio of the apoA-I content was constant within the HDL-cholesterol (HDL-C) range 0.59 to 2.24 mM. However, this ratio was significantly increased with an increase in the plasma triacylglycerol (TAG) content from 0.59 to 3.42 mM. A correlation of the level of preβ-HDL with the basal and ABCA1-mediated efflux of cholesterol is shown. The transcript levels for six HDL-metabolizing genes (LDLR, LCAT, ABCA1, SCARB1, ZDHHC8, and BMP1) were decreased, while the transcript level of APOA1 gene was increased in mononuclear cells of subjects with hyperalphalipoproteinemia as compared with subjects with hypoalphalipoproteinemia. A reduction of the intracellular cholesterol level and inhibition of the expression of cholesterol transporters by nascent HDL in mononuclear cells from subjects with hyperalphalipoproteinemia are suggested. Hyperalphalipoproteinemia can be a driving force of the decreased flux of cholesteryl ester to the liver and the increased TAG hydrolysis. The atheroprotective effect of preβ-HDL in hypertriglyceridemia is proposed.

Regular exercise and anabolic androgenic steroids have opposing effects on the plasma lipoprotein profile and risk of cardio-metabolic diseases in humans. Studies in humans and animal models show conflicting results. Here, we used a mice model genetically modified to mimic human lipoprotein profile and metabolism. They under-express the endogenous LDL receptor gene (R1) and express a human transgene encoding the cholesteryl ester transfer protein (CETP), normally absent in mice. The present study was designed to evaluate the independent and interactive effects of testosterone supplementation, exercise training and CETP expression on the plasma lipoprotein profile and CETP activity. CETP/R1 and R1 mice were submitted to a 6-week swimming training and mesterolone (MEST) supplementation in the last 3 weeks. MEST treatment increased markedly LDL levels (40%) in sedentary CETP/R1 mice and reduced HDL levels in exercised R1 mice (18%). A multifactorial ANOVA revealed the independent effects of each factor, as follows. CETP expression reduced HDL (21%) and increased non-HDL (15%) fractions. MEST treatment increased the VLDL concentrations (42%) regardless of other interventions. Exercise training reduced triacylglycerol (25%) and free fatty acids (20%), increased both LDL and HDL (25-33%), and reduced CETP (19%) plasma levels. Significant factor interactions showed that the increase in HDL induced by exercise is explained by reducing CETP activity and that MEST blunted the exercise-induced elevation of HDL-cholesterol. These results reinforce the positive metabolic effects of exercise, resolved a controversy about CETP response to exercise and evidenced MEST potency to counteract specific exercise benefits.

Plasma lipids have been extensively studied in sedentary and in subjects practicing exercise training, but not in extreme inactivity as occurs in bedridden patients. This is important for the care of bedridden patients and understanding the overall plasma lipid regulation. Here, we investigated plasma lipids, lipid transfers to HDL and inflammatory markers in bedridden patients. Fasting blood samples were collected from 23 clinically stable bedridden patients under long-term care (>90 days) and 26 normolipidemic sedentary subjects, paired for age and gender. In vitro transfer of four lipids to HDL was performed by incubating plasma with donor nanoparticles containing radioactive lipids. Total (193 ± 36 vs 160 ± 43, p = 0.005), LDL (124 ± 3 vs 96 ± 33 p = 0.003) and HDL-cholesterol (45 ± 10 vs 36 ± 13, p = 0.008), apolipoprotein A-I (134 ± 20 vs 111 ± 24, p = 0.001) and oxidized LDL (53 ± 13 vs 43 ± 12, p = 0.011) were lower in bedridden patients, whereas triglycerides, apolipoprotein B, CETP and LCAT were equal in both groups. Transfers of all lipids, namely unesterified cholesterol, cholesterol esters, triglycerides and phospholipids, to HDL were lower in bedridden patients, probably due to their lower HDL-cholesterol levels. Concentrations of IL-1β, IL-6, IL-8, HGF and NGF were higher in bedridden patients compared to sedentary subjects. In conclusion, inactivity had great impact on HDL, by lowering HDL-cholesterol, apolipoprotein A-I and thereby cholesterol transfers to the lipoprotein, which suggests that inactivity may deteriorate HDL protection beyond the ordinary sedentary condition.

Endothelial lipase (EL) is a major determinant of plasma HDL concentration, its activity being inversely proportional to HDL levels. Although it is known that it preferentially acts on HDL compared to LDL and VLDL, the basis for this specificity is not known. Here we tested the hypothesis that sphingomyelin, a major phospholipid in lipoproteins is a physiological inhibitor of EL, and that the preference of the enzyme for HDL may be due to low sphingomyelin/phosphatidylcholine (PtdCho) ratio in HDL, compared to other lipoproteins. Using recombinant human EL, we showed that sphingomyelin inhibits the hydrolysis of PtdCho in the liposomes in a concentration-dependent manner. While the enzyme showed lower hydrolysis of LDL PtdCho, compared to HDL PtdCho, this difference disappeared after the degradation of lipoprotein sphingomyelin by bacterial sphingomyelinase. Analysis of molecular species of PtdCho hydrolyzed by EL in the lipoproteins showed that the enzyme preferentially hydrolyzed PtdCho containing polyunsaturated fatty acids (PUFA) such as 22:6, 20:5, 20:4 at the sn-2 position, generating the corresponding PUFA-lyso PtdCho. This specificity for PUFA-PtdCho species was not observed after depletion of sphingomyelin by sphingomyelinase. These results show that sphingomyelin not only plays a role in regulating EL activity, but also influences its specificity towards PtdCho species.

Metabolic syndrome (MetS) refers to states of insulin resistance that predispose to development of cardiovascular disease and type 2 diabetes (T2DM). The aim was to investigate whether plasma lipids and lipid metabolism differ in MetS patients compared to those with T2DM with poor glycemic control (glycated hemoglobin7.0). Eighteen patients with T2DM, 18 with MetS and 14 controls, paired for age (40-70 years) and body mass index (BMI), were studied. Plasma lipids and the kinetics of a triacylglycerol-rich emulsion labeled with [(3)H]-triolein ([(3)H]-TAG) and [(14)C]-cholesteryl esters ([(14)C]-CE) injected intravenously followed by one-hour blood sampling were determined. Lipid transfers from an artificial nanoemulsion donor to high-density lipoprotien (HDL) were assayed in vitro. Low-density lipoprotein (LDL) and HDL cholesterol (mg/dl) were not different in T2DM (128 ± 7; 42 ± 7) and MetS (142 ± 6; 39 ± 3), but triacylglycerols were even higher in MetS (215 ± 13) than in T2DM (161 ±11, p0.05). Fractional clearance rate (FCR, in min(1)) of [(3)H]-TAG and [(14)C]-CE were equal in T2DM (0.008 ± 0.018; 0.005 ± 0.024) and MetS (0.010 ± 0.016; 0.006 ± 0.013), and both were reduced compared to controls. The transfer of non-esterified cholesterol, phospholipids and triacylglycerols to HDL was higher in MetS and T2DM than in controls (p0.01). Cholesteryl ester transfer and HDL size were equal in all groups. Results imply that MetS is equal to poorly controlled T2DM concerning the disturbances of plasma lipid metabolism examined here, and suggest that there are different thresholds for the insulin action on glucose and lipids. These findings highlight the magnitude of the lipid disturbances in MetS, and may have implications in the prevention of cardiovascular diseases.

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a key regulator of serum low density lipoprotein cholesterol levels. PCSK9 is secreted by the liver and binds the hepatic low density lipoprotein receptor, causing its subsequent degradation. PCSK9 has also been shown to regulate the levels of additional membrane-bound proteins in vitro, including very low-density lipoprotein receptor, apolipoprotein E receptor 2, and beta-site amyloid precursor protein-cleaving enzyme 1, which are highly expressed in central nervous system (CNS) and have been implicated in Alzheimer’s disease. Previous studies have demonstrated that human circulating PCSK9 displays a diurnal rhythm. Currently, little is known about PCSK9 levels in human cerebrospinal fluid (CSF). In the present study, we measured PCSK9 concentrations in both serum and CSF collected from healthy human subjects at multiple time points throughout the day. While PCSK9 in serum manifested a distinct diurnal pattern, CSF PCSK9 levels were remarkably constant throughout the course of the day and were also consistently lower than corresponding serum PCSK9 concentrations. Our results indicate that regulation of PCSK9 in human CSF may be different than for plasma PCSK9, suggesting that further study of the role of PCSK9 in the CNS is warranted.

Although hypocholesterolemia is a reported finding in sickle cell disease (SCD), low-density lipoprotein (LDL)/high-density lipoprotein (HDL) subfractions and HDL-associated enzymes have not been determined in SCD patients. Blood was collected from 38 hemoglobin (Hb)A volunteers and 45 homozygous HbSS patients who had not received blood transfusions in the last 3 months. Serum lipids were measured by automated analyzer while LDL and HDL subfraction analysis was done by continuous disc polyacrylamide gel electrophoresis. Serum levels of cholesteryl ester transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT), apolipoprotein B (apoB) and apolipoprotein A-1 (apoA-I) were determined by enzyme-linked immunosorbent assay (ELISA). Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels were significantly decreased, while TG levels were significantly increased in SCD patients compared to controls. A significant decrease in intermediate-density lipoprotein (IDL)-C, IDL-B, IDL-A and LDL-1 fractions were seen in SCD patients, while no significant difference was observed in small dense LDL particles. A significant decrease was seen in HDL-large, HDL-intermediate and HDL-small fractions in SCD patients versus controls. Levels of LCAT and ApoA-1 protein measured in SCD patients were significantly lower while no significant difference was observed in CETP and ApoB protein levels compared to controls. The reduction observed in LDL- and HDL-C in SCD patients was reflected as significantly decreased IDL, LDL-1 and HDL-subfractions. Decreased HDL subfractions may possibly lead to the reduced ApoA-1 and LCAT protein levels observed in SCD patients.

Dietary modification alters plasma lipoprotein profiles and atherosclerotic lesion progression in humans and some animal models. Variability in response to diet induced atherosclerosis has been reported in hamsters. Assessed was the interaction between background diet composition and dietary fat type on aortic cholesterol accumulation, lipoprotein profiles, hepatic lipids and selected genes. F1B Golden Syrian hamsters (20/group) were fed (12 weeks) semi-purified or non-purified diets containing either 10 % (w/w) coconut oil or safflower oil and 0.15 % (w/w) cholesterol. The non-purified diets relative to semi-purified diets resulted in significantly higher TC (72 % [percent difference] and 38 %, coconut oil and safflower oil, respectively) and nHDL-C (84 and 61 %, coconut oil and safflower oil, respectively), and lower HDL-C (−47 and −45 %, coconut oil and safflower oil, respectively) concentrations. Plasma triacylglycerol concentrations in the hamsters fed the non-purified coconut oil-supplemented diets were three- to fourfold higher than non-purified safflower oil-supplemented, and both semi-purified diets. With the exception of HDL-C, a significant effect of fat type was observed in TC, nHDL-C and triacylglycerol (all P < 0.05) concentrations. Regardless of diet induced differences in lipoprotein profiles, there was no significant effect on aortic cholesterol accumulation. There was an inverse relationship between plasma nHDL-C and triacylglycerol, and hepatic cholesteryl ester content (P < 0.001). Diet induced differences in hepatic gene transcription (LDL receptor, apoB-100, microsomal transfer protein) were not reflected in protein concentrations. Although hamsters fed non-purified and/or saturated fatty acid-supplemented diets had more atherogenic lipoprotein profiles compared to hamsters fed semi-purified and/or polyunsaturated fatty acid-supplemented diets these differences were not reflected in aortic cholesterol accumulation.

Fenofibrate and extended-release (ER) niacin similarly raise high-density lipoprotein cholesterol (HDL-C) concentration but their effects on levels of potent plasma antioxidant xanthophylls (lutein and zeaxanthin) and phytosterols obtained from dietary sources, and any relationship with plasma lipoproteins and pre-β1-HDL levels, have not been investigated. We studied these parameters in 66 dyslipidemic patients treated for 6 week with fenofibrate (160 mg/day) or ER-niacin (0.5 g/day for 3 week, then 1 g/day) in a cross-over study. Both treatments increased HDL-C (16 %) and apolipoprotein (apo) A-I (7 %) but only fenofibrate increased apoA-II (28 %). Lutein and zeaxanthin levels were unaffected by fenofibrate but inversely correlated with percentage change in apoB and low-density lipoprotein cholesterol and positively correlated with end of treatment apoA-II. ApoA-II in isolated HDL in vitro bound more lutein than apoA-I. Xanthophylls were increased by ER-niacin (each ~30 %) without any correlation to lipoprotein or apo levels. Only fenofibrate markedly decreased plasma markers of cholesterol absorption; pre-β1-HDL was significantly decreased by fenofibrate (−19 %, p < 0.0001), with little change (3.4 %) for ER-niacin. Although fenofibrate and ER-niacin similarly increased plasma HDL-C and apoA-I, effects on plasma xanthophylls, phytosterols and pre-β1-HDL differed markedly, suggesting differences in intestinal lipidation of HDL. In addition, the in vitro investigations suggest an important role of plasma apoA-II in xanthophyll metabolism.

Docosahexaenoic acid (DHA) status is related to health and disease risk. DHA status is mainly determined by dietary DHA intake, since endogenous synthesis of DHA is limited. We aimed to investigate the changes of different molecular glycerophospholipid species containing DHA in plasma and red blood cells (RBC) in response to increased DHA intake. Thirteen healthy adults had their diet supplemented with 510 mg DHA/day for 29 days. Fasted blood samples were taken at 11 time points and glycerophospholipid species were analyzed by liquid chromatography mass spectrometry. In plasma, percentages of glycerophospholipid species containing DHA increased significantly by 64–104 % relative to baseline values during supplementation, but the relative distribution between species was not markedly altered. In RBC, phosphatidylcholine (PtdCho) species containing DHA increased to a similar extent as in plasma, while phosphatidylethanolamine and phosphatidylserine species with DHA increased by only 12–25 %, respectively, which was significantly different compared to PtdCho species (p < 0.01). Despite the high increase, the contribution of DHA PtdCho species to total DHA remained minor (14 % after supplementation). In conclusion, DHA supplementation does not alter the relative distribution of DHA among glycerophospholipid species in plasma. A majority of PtdCho species are rapidly exchanged between plasma lipoproteins and RBC membrane lipids, while there is a minor exchange of phosphatidylethanolamine and phosphatidylserine species.

Epidemiologic and ecologic studies suggest that dietary fat plays an important role in the development of obesity. Certain Wistar rat strains do not become obese when fed high-fat diets unlike others. In a preliminary study, we confirmed that Slc:Wistar/ST rats did not become obese when fed high-fat diets. The mechanisms governing the response of hepatic lipid-metabolizing enzymes to large quantities of dietary lipids consumed by obesity-resistant animals are unknown. The aim of the present study is to examine how obesity-resistant animals metabolize various types of high-fat diets and why they do not become obese. For this purpose, male Slc:Wistar/ST rats were fed a control low-fat diet (LS) or a high-fat diet containing fish oil (HF), soybean oil (HS), or lard (HL) for 4 weeks. We observed their phenotypes and determined lipid profiles in plasma and liver as well as mRNA expression levels in liver of genes related to lipid and glucose metabolism using DNA microarray and quantitative reverse transcriptase polymerase chain analyses. The body weights of all dietary groups were similar due to isocaloric intakes, whereas the weight of white adipose tissues in the LS group was significantly lower. The HF diet lowered plasma lipid levels by accelerated lipolysis in the peroxisomes and suppressed levels of very-low-density lipoprotein (VLDL) secretion. The HS diet promoted hepatic lipid accumulation by suppressed lipolysis in the peroxisomes and normal levels of VLDL secretion. The lipid profiles of rats fed the LS or HL diet were similar. The HL diet accelerated lipid and glucose metabolism.

Alterations in high-density lipoprotein (HDL) subclass distribution, as well as in the activities of HDL-associated enzymes, have been associated with increased cardiovascular disease (CVD) risk. HDL subclass distribution and the activities of HDL-associated enzymes remain unknown in prediabetic patients, a condition also associated with increased CVD risk. The aim of the present study was to assess any differences in HDL subclass distribution (using polyacrylamide gel electrophoresis) and in activities of HDL-associated enzymes between prediabetic (impaired fasting glucose, IFG, n = 80) and non-prediabetic subjects (n = 105). Subjects with prediabetes had significantly increased waist circumference, blood pressure and triacylglycerol (TAG) levels compared with subjects with fasting glucose levels

Sixteen nuclear magnetic resonance (NMR) spectroscopy lipoprotein measurements of more than 1,000 subjects of GOLDN study, at fasting and at 3.5 and 6 h after a postprandial fat (PPL) challenge at visits 2 and 4, before and after a 3 weeks Fenofibrate (FF) treatment, were included in 6 time-independent multivariate factor analyses. Their top 1,541 unique SNPs were assessed for association with GOLDN NMR-particles and classical lipids. Several SNPs with −log10 p > 7.3 and MAF ≥ 0.10, mostly intergenic associated with NMR-single traits near genes FAM84B (8q24.21), CRIPT (2p21), ACOXL (2q13), BCL2L11 (2q13), PCDH10 (4q28.3), NXPH1 (7p22), and SLC24A4 (14q32.12) in association with NMR-LDLs; HOMER1 (5q14.2), KIT (4q11–q12), VSNL1 (2p24.3), QPRT (16p11.2), SYNPR (3p14.2), NXPH1 (7p22), NELL1 (11p15.1), and RUNX3 (1p36) with NMR-HDLs; and DOK5-CBLN4-MC3R (20q13), NELL1 (11p15.1), STXBP6 (14q12), APOB (2p24-p23), GPR133 (12q24.33), FAM84B (8q24.21) and NR5A2 (1q32.1) in association with NMR-VLDLs particles. NMR single traits associations produced 75 % of 114 significant candidates, 7 % belonged to classical lipids and 18 % overlapped, and 16 % matched for time of discovery between NMR- and classical traits. Five proxy genes, (ACOXL, FAM84B, NXPH1, STK40 and VAPA) showed pleiotropic effects. While tagged for significant associations in our study and with some extra evidence from the literature, candidates as CBNL4, FAM84B, NXPH1, SLC24A4 remain unclear for their functional relation to lipid metabolism. Although GOLDN study is one of the largest in studying PPL and FF treatment effects, the relatively small samples (over 700–1,000 subjects) in association tests appeals for a replication of such a study. Thus, further investigation is needed.

Oxidized low-density lipoprotein (OxLDL) plays an important role in initiation and progression of atherosclerosis. Proatherogenic effects of OxLDL have been attributed to bioactive phospholipids generated during LDL oxidation. It is unknown what effect oxidation has on the phosphatidylinositol (PtdIns) molecules in LDL, even though PtdIns is 6% of the total LDL phospholipid pool. We sought to identify and quantitate oxidized phosphatidylinositol (OxPtdIns) species in OxLDL and human atherosclerotic plaque. Bovine liver PtdIns was subjected to non-enzymatic and lipoxygenase-catalyzed oxidation. Reversed-phase liquid chromatography with negative ESI–MS identified and confirmed compounds by fragmentation pattern analysis from which an OxPtdIns library was generated. Twenty-three OxPtdIns molecules were identified in copper-oxidized human LDL at 0, 6, 12, 24, 30, and 48 h, and in human atherosclerotic plaque. In OxLDL, OxPtdIns species containing aldehydes and carboxylates comprised 17.3 ± 0.1 and 0.9 ± 0.2%, respectively, of total OxPtdIns in OxLDL at 48 h. Hydroperoxides and isoprostanes at 24 h (68.5 ± 0.2 and 22.8 ± 0.2%) were significantly greater than 12 h (P

Serum small dense low-density lipoprotein (sd-LDL) concentrations were measured in patients with angiographically defined coronary artery disease (CAD) and compared to concentrations in healthy subjects. Five hundred and seventy patients with stable CAD were divided into CAD- and CAD+ based on angiography. Patients in whom stenosis was50 % in diameter were classified as having a 'normal' angiogram (CAD-), otherwise the patients were allocated to the CAD+ group. The CAD+ group was further subcategorized into single-, double- and triple-vessel disease (VD). Serum sd-LDL concentrations were significantly lower in controls compared with CAD+ and CAD- patients (P 0.001). Moreover, CAD+ patients had higher concentrations of sd-LDL than CAD- patients (P 0.01). sd-LDL levels were not significantly associated with severity of CAD defined by the number of stenosed coronary arteries (P = 0.245). All participants were also categorized into subgroups with or without metabolic syndrome. Subjects with metabolic syndrome had higher levels of sd-LDL than subjects without metabolic syndrome (P 0.01). Multiple linear regressions showed that in CAD patients, triacylglycerol, total-cholesterol, body mass index, and waist circumferences were the most important determinants of serum sd-LDL concentrations. We found that sd-LDL levels were significantly higher in patients presenting with symptoms of CAD. Moreover, patients with significant stenosis of their coronary arteries (50 % stenosis) had higher levels of sd-LDL compared to patients without significant lesions.

The growth of the necrotic core region within advanced atherosclerotic plaque is thought to be driven by oxidised low density lipoprotein (oxLDL)-induced death of macrophage cells. OxLDL and atherosclerotic plaque are rich in oxysterols, especially 7-ketocholesterol (7KC). As 7KC triggers cell death at physiological concentrations when added directly to the cell culture media, 7KC and other oxysterols have been suggested to be the main cytotoxic agent of oxLDL. We investigated this hypothesis by examining the toxicity of 7KC to monocyte-like U937 cells when incorporated into high-uptake non-toxic acetylated LDL (acLDL). Incorporation of 7KC into acLDL greatly reduced the oxysterol toxicity when compared with an equivalent amount of 7KC added directly to U937 cells. Enrichment of oxLDL with 7KC did not significantly enhance lipoprotein toxicity. OxLDL was highly cytotoxic yet generated only low levels of intracellular 7KC. In comparison, 7KC-acLDL generated high intracellular 7KC concentrations with little loss in cell viability. The data show that when incorporated into lipoprotein, 7KC cytotoxicity is greatly reduced, even though intracellular levels exceed those measured when cells are incubated with oxLDL, which suggests 7KC is not the significant toxic agent within oxLDL.

Nutritional influences on cardiovascular disease operate throughout life. Studies in both experimental animals and humans have suggested that changes in the peri- and early post-natal nutrition can affect the development of the various components of the metabolic syndrome in adult life. This has lead to the hypothesis that n-3 fatty acid supplementation in pregnancy may have a beneficial effect on lipid profile in the offspring. The aim of the present study was to investigate the effect of supplementation with n-3 fatty acids during the third trimester of pregnancy on lipids and lipoproteins in the 19-year-old offspring. The study was based on the follow-up of a randomized controlled trial from 1990 where 533 pregnant women were randomized to fish oil (n = 266), olive oil (n = 136) or no oil (n = 131). In 2009, the offspring were invited to a physical examination including blood sampling. A total of 243 of the offspring participated. Lipid values did not differ between the fish oil and olive oil groups. The relative adjusted difference (95% confidence intervals) in lipid concentrations was -3% (-11; 7) for LDL cholesterol, 3% (-3; 10) for HDL cholesterol, -1% (-6; 5) for total cholesterol,-4% (-16; 10) for TAG concentrations, 2%(-2; 7) for apolipoprotein A1, -1% (-9; 7) for apolipoprotein B and 3% (-7; 15) in relative abundance of small dense LDL. In conclusion, there was no effect of fish oil supplementation during the third trimester of pregnancy on offspring plasma lipids and lipoproteins in adolescence.

The objective of the present study was to evaluate the effects of acute infection with Leptospira interrogans on lipids, lipoproteins and associated enzymes. Fasting serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), apolipoproteins (apo) A-Ι, B, E, C-II, C-III and lipoprotein (a) [Lp(a)] were determined in patients with Leptospirosis on diagnosis and 4 months after recovery as well as in age- and sex-matched controls. Activities of cholesteryl-ester transfer protein (CETP) and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) as well as paraoxonase 1 (PON1) hydrolysing activity and levels of cytokines were determined. LDL subclass analysis was performed with Lipoprint LDL System. Eleven patients (10 men, mean age 49.5 ± 8.4 years) and 11 controls were included. TC, HDL-C, LDL-C, apoA-I, apoB and Lp(a) levels were lower at baseline, whereas TG and apoE levels were elevated compared with 4 months later. At baseline, higher levels of cytokines and cholesterol concentration of small dense LDL particles (sdLDL-C) were noticed, whereas LDL particle size was lower compared with follow-up. Activities of plasma Lp-PLA(2) and HDL-associated Lp-PLA(2) were lower at baseline compared with post treatment values, whereas PON1 activity was similar at baseline and 4 months later. 4 months after recovery, the levels of all lipid parameters evaluated did not differ compared with controls, except for HDL-C which remained lower. PON1 activity both at baseline and 4 months later was lower in patients compared with controls. Leptospirosis is associated with atherogenic changes of lipids, lipoproteins and associated enzymes.

Macrophages in arterial walls accumulate lipids leading to the development of atherosclerotic plaques. However, mechanisms underlying macrophage lipid accumulation and foam cell formation are often studied without accounting for risk factors such as dyslipidemia. We investigated the effect of varying concentrations of triglyceride (TG) within physiological range on macrophage fatty acid (FA) accumulation and expression of cholesterol efflux proteins. Human monocytes were cultured in media supplemented with 10% sera containing low (0.7 mmol/L) to high (1.4 mmol/L) TG. The resulting macrophages were harvested after 10 days for analysis of FA content and composition and expression of genes involved in lipid metabolism. Exposure to higher TG and lower HDL concentrations in media increased macrophage lipid content. Macrophages exposed to higher TG had increased total FA content compared with controls (876 μg/mg protein vs. 652 μg/mg protein) and greater proportions of C16:0, C18:1 and C18:2. Macrophage expression of both ABCA1 and ABCG1 cholesterol efflux proteins were reduced when higher TG concentrations were present in the media. Expression of scavenger receptor CD36, involved in lipoprotein uptake, was also downregulated in macrophages exposed to higher TG. Culturing macrophages in conditions of higher versus lower TG influenced macrophage FA content and composition, and levels of regulatory proteins. Replicating in vitro levels of dyslipidemia encountered in vivo may provide an informative model for investigation of atherogenesis.

Apolipoprotein C-III (apoC-III) decreases the apolipoprotein E (apoE)-mediated uptake of lipoprotein remnants by the liver, and a high plasma concentration of apoC-III in VLDL is associated with hypertriglyceridemia and the risk of coronary heart disease. In this study, we prepared lipid emulsions containing triolein, phosphatidylcholine and cholesterol as model particles of lipoproteins, and examined the roles of apoC-III in apoE-mediated uptake of emulsions by HepG2 cells. Cholesterol in emulsion particles enhanced the apoE-mediated uptake via heparan sulfate proteoglycan and LDL receptor-related protein pathways. The amount of apoE bound to emulsion particles was increased by the presence of cholesterol at the particle surface, whereas cholesterol had no effect on the binding amount of apoC-III. Surface cholesterol alleviated the inhibitory effect of apoC-III on apoE incorporation into the emulsion surface. However, ApoC-III almost completely inhibited the apoE-mediated uptake of cholesterol-containing emulsions despite sufficient binding of apoE to emulsions. These findings suggest that apoC-III attenuates the binding of apoE to the lipoprotein surface and apoE-mediated cellular uptake of lipoprotein remnants. Furthermore, cholesterol may affect these functions of apoC-III and apoE involved in the clearance of lipoprotein remnants.

Atherogenic dyslipidemia comprises a triad of increased blood concentrations of small, dense low-density lipoprotein (LDL) particles, decreased high-density lipoprotein (HDL) particles, and increased triglycerides. A typical feature of obesity, the metabolic syndrome, insulin resistance, and type 2 diabetes mellitus, atherogenic dyslipidemia has emerged as an important risk factor for myocardial infarction and cardiovascular disease. A number of genes have now been linked to this pattern of lipoprotein changes. Low-carbohydrate diets appear to have beneficial lipoprotein effects in individuals with atherogenic dyslipidemia, compared to high-carbohydrate diets, whereas the content of total fat or saturated fat in the diet appears to have little effect. Achieving a better understanding of the genetic and dietary influences underlying atherogenic dyslipidemia may provide clues to improved interventions to reduce the risk of cardiovascular disease in high-risk individuals.

Oxidized low-density lipoprotein (ox-LDL) plays a key role in the progression of atherosclerosis and diabetes complications. The aim of this study was first, to evaluate the association between ox-LDL and diabetes duration, and second, to examine serum level of ox-LDL in patients with prolonged diabetes and a desirable LDL-cholesterol level. A total of 36 type-2 diabetic patients with a diabetes duration of more than 5 years, 36 newly diagnosed diabetic patients, and 36 age-, sex- and BMI-matched healthy participants were recruited. Healthy participants and newly diagnosed patients were not receiving any treatment. All patients with prolonged diabetes had desirable LDL-cholesterol levels (100 mg/dL), according to the adult treatment panel-III guidelines. While LDL-cholesterol was significantly lower in patients with diabetes duration5 years, in comparison to newly diagnosed patients (P0.01), ox-LDL was significantly higher in patients with prolonged diabetes (P0.001). The ox-LDL-to-LDL ratio was dramatically higher in patients with diabetes duration5 years in comparison to newly diagnosed patients and healthy participants (P0.001). Ox-LDL was significantly associated with diabetes duration (r = 0.519, P = 0.001). In multivariate analysis, this association remained significant (beta = 0.501, P = 0.003) after adjustment for potential confounders. In conclusion, this study showed that the serum ox-LDL level increases with the length of diabetes, even though the patients' LDL-cholesterol level is maintained at a desirable level. Our findings highlight that possibly more attention should be focused on markers of oxidative stress in the management of lipids in diabetic patients.

An open-labeled randomized trial with parallel groups was carried out to study the effects of Dif1stat (Monascus purpureus-Linear aliphatic alcohols-Niacin) in the treatment of primary moderate hypercholesterolemia. The trial lasted 8 months. The patients, males and females, were assigned to two groups: A (#130), treated with diet, and B (#110) submitted to diet + Dif1stat. After 4 months, group A did not show significant changes in Total cholesterol (TC), LDL-cholesterol (LDLC), HDL-cholesterol (HDLC) or non-HDL-cholesterol (non-HDLC). The same group, showed a reduction in TC (-22%), LDLC (-30%) and non-HDLC (-27%) after 8 months (Por = 0.001). After 4 months, TC (-21.3%), LDLC (-29%), and non-HDLC (-26%) were significantly lowered in group B (Por = 0.001). In group B, TC, LDLC and non-HDLC showed a further reduction after 8 months: -29.4, -38 and -37%, respectively (Por = 0.001). Even triglycerides (TG) decreased significantly (-33%) (Por = 0.001). After 8 months, group B showed a significant reduction of TG (-33%) (Por = 0.001), when compared to group A. Some safety parameters were significantly reduced in both groups: AST and gamma-GT in group A after 4 and 8 months, as well as ALT, AST and gamma-GT in group B after 8 months (Por = 0.001). Dif1stat, given with a suitable diet, was well tolerated in the long-term and induced an anti-atherogenic plasma lipid and lipoprotein profile, in patients with moderate hypercholesterolemia.

Statins, inhibitors of HMG-CoA reductase, reduce plasma low-density lipoprotein (LDL) cholesterol levels decreasing the incidence of coronary events. However, the observed benefit of statins appears to extend beyond their lipid-lowering effects. Previous studies by our group have demonstrated that atorvastatin in oxidized LDL incubated macrophages modifies the gene expression profile of certain enzymes involved in fatty acid metabolism, mainly stearoyl-CoA desaturase (SCD). SCD is a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids and its expression is mediated by sterol regulatory element-binding protein-1 (SREBP-1). The aim of this study was to determine whether atorvastatin might affect the fatty acid composition in macrophages and if their SCD gene expression profile could explain this effect. Therefore, THP-1 macrophages were treated with atorvastatin and native or oxidized LDL, their fatty acid composition was determined by gas-chromatography, and the SCD and SREBP-1 gene expression profile was analysed using quantitative RT-PCR. We found that atorvastatin reduces the percentage of palmitoleic and oleic acids in THP-1 cells incubated with oxLDL, which could be explained by the inhibition of SCD and SREBP-1 gene expression. The observed results were reversed when mevalonate was added to THP-1 macrophages. This would suggest that inhibition of SCD in THP-1 macrophages incubated with oxLDL and the change in fatty acid composition is an important effect of atorvastatin.

The present study determined alpha-tocopherol mass transfer from an alpha-tocopherol-rich emulsion to LDL and HDL, and assessed the potential of different mechanisms to modulate alpha-tocopherol transfers. Emulsion particles rich in alpha-tocopherol were incubated in vitro with physiological concentrations of LDL or HDL. The influence of plasma proteins was assessed by adding human lipoprotein poor plasma (LPP) fraction with intact vs heat inactivated PLTP, or with a specific cholesteryl ester transfer protein (CETP) inhibitor, or by adding purified PLTP or pig LPP which lacks CETP activity. After 4 h incubation in absence of LPP, alpha-tocopherol content was increased by ~80% in LDL and ~160% in HDL. Addition of LPP markedly enhanced alpha-tocopherol transfer leading to 350-400% enrichment in LDL or HDL at 4 h. Higher (~10 fold) enrichment was achieved after 20 h incubation with LPP. Facilitation of alpha-tocopherol transfer was (i) more than 50% higher with human vs pig LPP (despite similar PLTP phospholipid transfer activity), (ii) reduced by specific CETP activity inhibition, (iii) not fully suppressed by heat inactivation, and (iv) not restored by purified PLTP. In conclusion, alpha-tocopherol content in LDL and HDL can be markedly raised by rapid transfer from an alpha-tocopherol-rich emulsion. Our results indicate that alpha-tocopherol mass transfer between emulsion particles and lipoproteins is mediated by more than one single mechanism and that this transfer may be facilitated not only by PLTP but likely also by other plasma proteins such as CETP.

Peroxisome proliferator-activated receptor alpha (PPARalpha) belongs to the nuclear receptor superfamily that regulates multiple target genes involved in lipid metabolism. Cholesterol ester transfer protein (CETP) is a secreted glycoprotein that modifies high-density lipoprotein (HDL) particles. In humans, plasma CETP activity is inversely correlated with HDL cholesterol levels. We report here that PPARalpha agonists increase CETP mRNA, protein and accordingly its activity. In a human CETP transgenic animal model harboring the natural flanking regions (Jiang et al. in J Clin Investigat 90:1290-1295, 1992), both fenofibrate and a specific synthetic PPARalpha agonist LY970 elevated human CETP mRNA in liver, serum protein and CETP activity. In hamsters, the endogenous liver CETP mRNA level and the serum CETP activity were dose-dependently upregulated by fenofibrate. In addition Wy14643, a PPARalpha agonist, also significantly elevated CETP mRNA and activity. In a carcinoma cell line of hepatic origin, HepG2 cells, overexpression of PPARalpha resulted in increased CETP mRNA and agonist treatment further elevated CETP mRNA levels. We conclude that PPARalpha agonists upregulate CETP expression and activity and may play an important role in PPARalpha (agonist mediated HDL cholesterol homeostasis in humans.

Liver and intestine are major sites of apo A-I synthesis in mammals. ABCAI is reported to be involved in the secretion of nascent HDL from cultured intestinal cells. However, whether ABCA1 participates in the secretion of nascent HDL from the intestine has not been assessed directly in vivo. This study examined the effect of a synthetic LXR-agonist “TO” on the lymphatic transport of HDL in thoracic duct-cannulated rats. The feeding of a TO-containing diet resulted in an increased transport of cholesterol and apo A-I in the lymph d > 1.063 g/ml lipoprotein fraction than did the feeding of a control diet without TO. The transport of cholesterol in whole lymph was lower, whereas the transport of apo A-I was higher, in the TO group. The abundance of mRNAs for ABCAI and apo A-I in the intestine was increased in the TO group. Furthermore, although the TO-containing diet reportedly increased the serum HDL concentration in intact mice and rats, no such effect was observed in the cannulated rats. The LXR agonist stimulated in vivo the synthesis of nascent HDL by increasing reciprocally the mRNA for ABCAI and apo A-I in the intestine, thereby contributing to an increase in the circulating HDL.

We have established a sensitive and convenient method for analysis of cholesterol hydroperoxides (Chol-OOHs) as trimethylsilyloxyl derivatives using diphenylpyrenylphosphine (DPPP)-thin-layer chromatography (TLC) blotting and gas chromatography-electron ionization-mass spectrometry/selected-ion monitoring (GC-EI-MS/SIM). Chol-OOH standards were prepared by photosensitized oxidation and azo radical-induced peroxidation of cholesterol. Trimethylsilyloxyl derivatives of cholesterol 5alpha-hydroperoxide (Chol 5alpha-OOH), cholesterol 7alpha-hydroperoxide (Chol 7alpha-OOH), and cholesterol 7beta-hydroperoxide (Chol 7beta-OOH) could be separated from one another in the SIM chromatogram using a fragment ion with elimination of trimethylsilanol from the molecular ion. This method was used to characterize peroxidized cholesterol from azo radical-exposed human low-density lipoprotein and UVA-irradiated human keratinocytes in the presence of hematoporphyrin. Finally, we succeeded in the quantification of each Chol-OOH isomer present in hairless mouse skin with and without UVA irradiation by use of beta-sitosterol hydroperoxide as internal standard. The accumulation of Chol 5alpha-OOH with Chol 7alpha/betaOOH in the skin indicates that singlet molecular oxygen ((1)O(2)) participated in the peroxidation of skin cholesterol, because Chol 5alpha-OOH is known to be a (1)O(2) specific cholesterol peroxidation product. We concluded that the combination of DPPP-TLC blotting and GC-EI-MS/SIM is useful for quantifying peroxidized cholesterol in biological samples and confirming the participation of (1)O(2) in oxidative stress.

Postprandial chylomicrons are potent ultimate acceptors of cell membrane cholesterol and are believed to accelerate reverse cholesterol transport (RCT). We compared the effects of meals rich in polyunsaturated fat (PUFA) and either high (605 mg) or low (151 mg) in cholesterol and a meal rich in dairy fat (DF) in the form of cream on net in vitro transport of red blood cell (RBC) membrane cholesterol to 4 and 6 h postprandial plasma in eight normotriglyceridemic (NTG-H) and eight hypertriglyceridemic (HTG-H) men with mild to moderate hypercholesterolemia. In HTG-H men, cell cholesterol accumulation in 6-h postprandial plasma was significantly (P = 0.02) less after the PUFA-HC meal compared with the other meals. The significant (P < 0.001) increase in cell plus endogenous cholesterol accumulation in the triglyceride-rich lipoprotein (TRL) fraction of 4 h postprandial plasma incubated with RBC was significantly (P = 0.007) higher after the PUFA-HC meal compared with DF meal in HTG-H men. In NTG-H men, cholesterol accumulation in plasma and plasma lipoproteins in the presence and absence of RBC was not significantly affected by the type of meal ingested. These data suggest that addition of large amounts of cholesterol to a PUFA meal may impair diffusion-mediated transport of cell membrane cholesterol to postprandial plasma and that replacing DF with PUFA in a meal increases postprandial lipemia and may potentially increase cholesterol accumulation in atherogenic postprandial TRL in HTG-H men.