Practical Methods for Plasma Lipoprotein Analysis1 1Work supported in part by the U.S. Atomic Energy Commission and by grants (HE06222 and FR00102) from the U.S. Public Health Service

C3H/HeNSlc mouse with low phospholipid transfer protein expression showed dyslipidemia

High serum levels of triglycerides (TG) and low levels of high-density lipoprotein cholesterol (HDL-C) increase the risk of coronary heart disease in humans. Herein, we first reported that the C3H/HeNSlc (C3H-S) mouse, a C3H/HeN-derived substrain, is a novel model for dyslipidemia. C3H-S showed hypertriglyceridemia and low total cholesterol (TC), HDL-C, and phospholipid (PL) concentrations. To identify the gene locus causing dyslipidemia in C3H-S, we performed genetic analysis. In F2 intercrosses between C3H-S mice and strains with normal serum lipids, the locus associated with serum lipids was identified as 163-168 Mb on chromosome 2. The phospholipid transfer protein (Pltp) gene was a candidate gene within this locus. Pltp expression and serum PLTP activity were markedly lower in C3H-S mice. Pltp expression was negatively correlated with serum TG and positively correlated with serum TC and HDL-C in F2 mice. Genome sequencing analysis revealed that an endogenous retrovirus (ERV) sequence called intracisternal A particle was inserted into intron 12 of Pltp in C3H-S. These results suggest that ERV insertion within Pltp causes aberrant splicing, leading to reduced Pltp expression in C3H-S. This study demonstrated the contribution of C3H-S to our understanding of the relationship between TG, TC, and PL metabolism via PLTP.

Plasma Membrane Localization of CD36 Requires Vimentin Phosphorylation; A Mechanism by Which Macrophage Vimentin Promotes Atherosclerosis

Vimentin is a type III intermediate filament protein expressed in cells of mesenchymal origin. Vimentin has been thought to function mainly as a structural protein and roles of vimentin in other cellular processes have not been extensively studied. Our current study aims to reveal functions of vimentin in macrophage foam cell formation, the critical stage of atherosclerosis. We demonstrated that vimentin null (Vim -/ - ) mouse peritoneal macrophages take up less oxidized LDL (oxLDL) than vimentin wild type (Vim +/+) macrophages. Despite less uptake of oxLDL in Vim -/ - macrophages, Vim +/+ and Vim -/ - macrophages did not show difference in expression of CD36 known to mediate oxLDL uptake. However, CD36 localized in plasma membrane was 50% less in Vim -/ - macrophages than in Vim +/+ macrophages. OxLDL/CD36 interaction induced protein kinase A (PKA)-mediated vimentin (Ser72) phosphorylation. Cd36 -/ - macrophages did not exhibit vimentin phosphorylation (Ser72) in response to oxLDL. Experiments using phospho-mimetic mutation of vimentin revealed that macrophages with aspartate-substituted vimentin (V72D) showed more oxLDL uptake and membrane CD36. LDL receptor null (Ldlr -/ - ) mice reconstituted with Vim -/ - bone marrow fed a western diet for 15 weeks showed 43% less atherosclerotic lesion formation than Ldlr -/ - mice with Vim +/+ bone marrow. In addition, Apoe -/ -Vim- / - (double null) mice fed a western diet for 15 weeks also showed 57% less atherosclerotic lesion formation than Apoe -/ - and Vim +/+mice. We concluded that oxLDL via CD36 induces PKA-mediated phosphorylation of vimentin (Ser72) and phosphorylated vimentin (Ser72) directs CD36 trafficking to plasma membrane in macrophages. This study reveals a function of vimentin in CD36 trafficking and macrophage foam cell formation and may guide to establish a new strategy for the treatment of atherosclerosis.

High-density lipoprotein in Alzheimer's disease: From potential biomarkers to therapeutics

The inverse correlation between high-density lipoprotein (HDL) levels in vivo and the risk of Alzheimer's disease (AD) has become an inspiration for HDL-inspired AD therapy, including plain HDL and various intelligent HDL-based drug delivery systems. In this review, we will focus on the two endogenous HDL subtypes in the central nervous system (CNS), apolipoprotein E-based HDL (apoE-HDL) and apolipoprotein A-I-based HDL (apoA-I-HDL), especially their influence on AD pathophysiology to reveal HDL's potential as biomarkers for risk prediction, and summarize the relevant therapeutic mechanisms to propose possible treatment strategies. We will emphasize the latest advances of HDL as therapeutics (plain HDL and HDL-based drug delivery systems) to discuss the potential for AD therapy and review innovative techniques in the preparation of HDL-based nanoplatforms to provide a basis for the rational design and future development of anti-AD drugs.

Comprehensive Glycomic Approach Reveals Novel Low-Molecular-Weight Blood Group-Specific Glycans in Serum and Cerebrospinal Fluid

ABO blood antigens on the human red blood cell membrane as well as different cells in various human tissues have been thoroughly studied. Anti-A and -B antibodies of IgM are present in serum/plasma, but blood group-specific glyco-antigens have not been extensively described. In this study, we performed comprehensive and quantitative serum glycomic analyses of various glycoconjugates and free oligosaccharides in all blood groups. Our comprehensive glycomic approach revealed that blood group-specific antigens in serum/plasma are predominantly present on glycosphingolipids on lipoproteins rather than glycoproteins. Expression of the ABO antigens on glycosphingolipids depends not only on blood type but also on secretor status. Blood group-specific glycans in serum/plasma were classified as type I, whereas those on RBCs had different structures including hexose and hexosamine residues. Analysis of free oligosaccharides revealed that low-molecular-weight blood group-specific glycans, commonly containing lacto-N-difucotetraose, were expressed in serum/plasma according to blood group. Furthermore, comprehensive glycomic analysis in human cerebrospinal fluid showed that many kinds of free oligosaccharides were highly expressed, and low-molecular-weight blood group-specific glycans, which existed in plasma from the same individuals, were present. Our findings provide the first evidence for low-molecular-weight blood group-specific glycans in both serum/plasma and cerebrospinal fluid.

Comparison of three equations for estimating low-density lipoprotein-cholesterol in the rural northeastern region of Thailand

BACKGROUND

Cardiovascular disease is the most common cause of death worldwide, and the detection of LDL-C contributes to reducing risks. However, the LDL-C is rarely evaluated according to the gold standard method because it is costly and time-consuming. This study aimed to determine the agreement of LDL-C among three equations, namely Friedewald's equation, Puavilai's equation, and Dansethakul's equation.

METHODS

A cross-sectional descriptive study.

RESULTS

Using the data of lipid measurement from a specific group of people in the remote rural area, we found that the Thai equations have more superior agreement with direct measurement than the Friedewald equation (ICC = 0.870, 95% CI = 0.857-0.882) when the agreement of continuous data was used for total analysis. Although the categorical analysis that gave better agreement was from Friedewald equation (K index = 0.730, 95% CI = 0.720-0.751), the findings from this study confirmed the population-specific use of Pauvilai's equation and Dansethakul's equation for determining the LDL-C.

CONCLUSION

Pauvilai's equation showed better agreement with direct measurement for LDL-C. Thus, it could be considered as an alternative for the direct method, particularly in laboratories in rural areas in Thailand.

Relative effect of hypertriglyceridemia on non-HDLC and apolipoprotein B as cardiovascular disease risk markers

BACKGROUND

Non-high density lipoprotein cholesterol (non-HDLC) represents the cholesterol in triglyceride-rich lipoproteins (TRL) and low-density lipoproteins (LDL). Apolipoprotein B (apoB) reflects the number of TRL and LDL particles. In hypertriglyceridemia (HTG), there is triglyceride (TG) enrichment of TRLs, and also a substantial increase of cholesterol in larger TRLs that considerably augments the non-HDLC value. Therefore, in HTG, non-HDLC could increase disproportionately with respect to apoB.

OBJECTIVE

We aimed to compare the relative effect of the full range of mild, moderate, and severe HTG on the status of non-HDLC and apoB as cardiovascular disease (CVD) risk markers.

METHODS

Analysis of lipid profile data from 4347 patients in a Lipid Clinic cohort with baseline fasting lipid profiles documented prior to starting lipid-lowering medications. The correlation between non-HDLC and apoB was assessed in intervals of increasing TG. Non-HDLC and apoB were analyzed at each TG level using comparative CVD risk equivalent categories and assessed for divergence and discordance.

RESULTS

With increasing TG levels: (1) the correlation between non-HDLC and apoB diminished progressively, (2) non-HDLC levels increased continuously, whereas apoB levels plateaued after an initial increase up to TG of ~ 4.0-5.0 mmol/L (~354-443 mg/dL), (3) there was divergence in the stratification of non-HDLC and apoB into CVD risk equivalent categories.

CONCLUSIONS

Non-HDLC and apoB should not be viewed as interchangeable CVD risk markers in the presence of severe HTG. This has never been tested. With increasing HTG severity, discordance between non-HDLC and apoB can cause clinically important divergence in CVD risk categorization.

Anti-Inflammatory Actions of Soluble Ninjurin-1 Ameliorate Atherosclerosis

BACKGROUND

Macrophages produce many inflammation-associated molecules, released by matrix metalloproteinases, such as adhesion molecules, and cytokines, as well, which play a crucial role in atherosclerosis. In this context, we investigated the relationship between Ninjurin-1 (Ninj1 [nerve injury-induced protein]), a novel matrix metalloproteinase 9 substrate, expression, and atherosclerosis progression.

METHODS

Ninj1 expression and atherosclerosis progression were assessed in atherosclerotic aortic tissue and serum samples from patients with coronary artery disease and healthy controls, and atheroprone apolipoprotein e-deficient (Apoe^-/-) and wild-type mice, as well. Apoe^-/- mice lacking systemic Ninj1 expression (Ninj1^-/-Apoe^-/-) were generated to assess the functional effects of Ninj1. Bone marrow transplantation was also used to generate low-density lipoprotein receptor-deficient (Ldlr^-/-) mice that lack Ninj1 specifically in bone marrow-derived cells. Mice were fed a Western diet for 5 to 23 weeks, and atherosclerotic lesions were investigated. The anti-inflammatory role of Ninj1 was verified by treating macrophages and mice with the peptides Ninj1_1-56 (ML56) and Ninj1_26-37 (PN12), which mimic the soluble form of Ninj1 (sNinj1).

RESULTS

Our in vivo results conclusively showed a correlation between Ninj1 expression in aortic macrophages and the extent of human and mouse atherosclerotic lesions. Ninj1-deficient macrophages promoted proinflammatory gene expression by activating mitogen-activated protein kinase and inhibiting the phosphoinositide 3-kinase/Akt signaling pathway. Whole-body and bone marrow-specific Ninj1 deficiencies significantly increased monocyte recruitment and macrophage accumulation in atherosclerotic lesions through elevated macrophage-mediated inflammation. Macrophage Ninj1 was directly cleaved by matrix metalloproteinase 9 to generate a soluble form that exhibited antiatherosclerotic effects, as assessed in vitro and in vivo. Treatment with the sNinj1-mimetic peptides, ML56 and PN12, reduced proinflammatory gene expression in human and mouse classically activated macrophages, thereby attenuating monocyte transendothelial migration. Moreover, continuous administration of mPN12 alleviated atherosclerosis by inhibiting the enhanced monocyte recruitment and inflammation characteristics of this disorder in mice, regardless of the presence of Ninj1.

CONCLUSIONS

Ninj1 is a novel matrix metalloproteinase 9 substrate in macrophages, and sNinj1 is a secreted atheroprotective protein that regulates macrophage inflammation and monocyte recruitment in atherosclerosis. Moreover, sNinj1-mediated anti-inflammatory effects are conserved in human macrophages and likely contribute to human atherosclerosis.

Association of TCF7L2 rs7903146 Polymorphism with the Risk of Type 2 Diabetes Mellitus (T2DM) Among Kurdish Population in Erbil Province, Iraq

The genetic predispositions responsible for developing type 2 diabetes mellitus (T₂DM) in the Middle East are poorly understood. The rs7903146 single nucleotide polymorphism (SNP) located in transcription factor 7-like-2 (TCF7L2) gene has been recognized to have a vital role in the development of T₂DM disorder. The current study is the first to have researched the possible association between TCF7L2 rs7903146 SNP and T₂DM among Kurdish population in Kurdistan region of Iraq. The study included 212 participants, half of them were T₂DM patients, and the other half were disease-free and normoglycemic controls. Genotyping was performed by using a high throughput cost and time effective tetra-primer amplification refractory mutation system-polymerase chain reaction (Tetra ARMS-PCR) assay. The rs7903146 genotypic frequencies for CC, CT and TT were 24.5%, 69.8%, and 5.7% in T₂DM group respectively, and for the controls were 45.3%, 50.9%, and 3.8% respectively. The frequency of CT genotype was found significantly higher in the cases when compared to the controls (OR = 2.53, 95% CI 1.40-4.57, P value < 0.0019), which indicated that the genotype CT showed risk with diabetes. The T allele showed a high significant frequency in the patients compared to the controls (OR = 1.65, 95% CI 1.10-2.47, P value = 0.014). Our findings demonstrated that the T allele could be a risk factor for increasing the susceptibility of T₂DM incidence among the Iraqi Kurdish population.

Oxidized LDL induces vimentin secretion by macrophages and contributes to atherosclerotic inflammation

Activated macrophages show increased expression of vimentin, an intermediate filament protein. Macrophages secrete vimentin into extracellular space; however, the functions of extracellular vimentin and the process of vimentin secretion are not clearly defined. We found that oxidized low-density lipoproteins (oxLDL) via CD36 induced vimentin secretion in macrophages. We also revealed that extracellular vimentin induced macrophages to release inflammatory cytokines and augmented oxLDL-induced release of TNF-α and IL-6. Extracellular vimentin activated NF-κB signaling via phosphorylation of focal adhesion kinase (p-FAK) and IκB kinase (p-IκK). Extracellular vimentin also amplified the oxLDL-induced p-IκK increase and IκB decrease. Vimentin-induced TNF-α release was not dependent on Dectin-1, which is known to bind vimentin. We measured serum vimentin concentrations and found that patients with atherosclerotic coronary artery disease had higher levels of serum vimentin than normal subjects. Circulating oxLDL and vimentin concentrations showed a high degree of correlation. In mouse experiments, vimentin concentration was higher in the sera of apoE null mice with western diet-induced atherosclerosis than in the sera of chow diet-fed apoE null mice without atherosclerosis. We concluded that vimentin is secreted by oxLDL/CD36 interaction in macrophages and extracellular vimentin promotes macrophage release of pro-inflammatory cytokines. This may contribute to atherosclerotic inflammation and based on our analysis of serum vimentin, we suggest serum vimentin as a predictive marker for atherosclerosis. KEY MESSAGES: OxLDL via CD36 induces secretion of vimentin, a cytoskeletal protein in macrophages. Extracellular vimentin induces macrophages to release proinflammatory cytokines such as tumor necrotizing factor-alpha (TNF-α) and this process is mediated by activation of focal adhesion kinase (FAK) and NF-ƙB signaling. Serum concentrations of vimentin in coronary artery disease patients are higher than that in control group. Vimentin concentration is strongly correlated with oxLDL concentration in serum.

Calculated Non-HDL Cholesterol Includes Cholesterol in Larger Triglyceride-Rich Lipoproteins in Hypertriglyceridemia

Context

Calculated non–high-density lipoprotein (HDL) cholesterol (non-HDLC) should selectively include cholesterol from atherogenic lipoproteins to be a reliable risk marker of cardiovascular disease. In hypertriglyceridemia (HTG), there is increased abundance of larger and less atherogenic triglyceride-rich lipoproteins (TRL), namely, larger very-low-density lipoproteins (VLDL), and chylomicrons.

Objective

We aim to demonstrate that serum triglyceride (TG) level has a substantial impact on non-HDLC’s ability to represent cholesterol from atherogenic lipoproteins, even though TG is not part of the calculation for non-HDLC.

Design

Analysis of lipid profile data

Settings

Lipid Clinic patient cohort, and Biochemistry Laboratory patient cohort

Patients or Other Participants

7,492 patients in the Lipid Clinic cohort with baseline lipid profiles documented prior to starting lipid-lowering medications and 156,311 lipid profiles from The Ottawa Hospital Biochemistry Laboratory cohort.

Intervention

None

Main Outcome Measure

Our modeling process includes derivation of TG-interval–specific lipoprotein composition factor (LCF) for TRL, which represents the mass ratio of cholesterol to TG in TRL. A high LCF indicates that the TRLs are mainly the cholesterol-rich atherogenic remnant lipoproteins. A low LCF indicates that the TRLs are mainly the TG-rich larger VLDL and chylomicrons.

Results

As serum TG increases, there is progressive decline in the LCF for TRL, which indicates that the calculated non-HDLC level reflects progressive inclusion of cholesterol from larger TRL. This is shown in both cohorts.

Conclusions

Calculated non-HDLC is influenced by TG level. As TG increases, non-HDLC gradually includes more cholesterol from larger TRL, which are less atherogenic than LDL and remnant lipoproteins.

The hepatic WASH complex is required for efficient plasma LDL and HDL cholesterol clearance

The evolutionary conserved Wiskott-Aldrich syndrome protein and SCAR homolog (WASH) complex is one of the crucial multiprotein complexes that facilitates endosomal recycling of transmembrane proteins. Defects in WASH components have been associated with inherited developmental and neurological disorders in humans. Here, we show that hepatic ablation of the WASH component Washc1 in chow-fed mice increases plasma concentrations of cholesterol in both LDLs and HDLs, without affecting hepatic cholesterol content, hepatic cholesterol synthesis, biliary cholesterol excretion, or hepatic bile acid metabolism. Elevated plasma LDL cholesterol was related to reduced hepatocytic surface levels of the LDL receptor (LDLR) and the LDLR-related protein LRP1. Hepatic WASH ablation also reduced the surface levels of scavenger receptor class B type I and, concomitantly, selective uptake of HDL cholesterol into the liver. Furthermore, we found that WASHC1 deficiency increases LDLR proteolysis by the inducible degrader of LDLR, but does not affect proprotein convertase subtilisin/kexin type 9-mediated LDLR degradation. Remarkably, however, loss of hepatic WASHC1 may sensitize LDLR for proprotein convertase subtilisin/kexin type 9-induced degradation. Altogether, these findings identify the WASH complex as a regulator of LDL as well as HDL metabolism and provide in vivo evidence for endosomal trafficking of scavenger receptor class B type I in hepatocytes.

Effects of a lifestyle intervention on markers of cardiometabolic risk and oxidized lipoproteins among obese adolescents with prediabetes

OBJECTIVE

Obesity and hyperglycaemia contribute to the atherosclerotic process in part through oxidative modifications to lipoprotein particles. The present study aimed to evaluate the effects of a lifestyle intervention on markers of oxidized lipoproteins in obese Latino adolescents with prediabetes.

DESIGN

Pre-post design.

SETTING

Participants were enrolled into a 12-week lifestyle intervention. Measurements pre- and post-intervention included anthropometrics and body composition, lipid panel, oxidized LDL (oxLDL), oxidized HDL (oxHDL), intake of fresh fruits and vegetables, and cardiorespiratory fitness.

PARTICIPANTS

Thirty-five obese Latino adolescents (seventeen females, eighteen males; mean age 15·5 (sd 1·0) years; mean BMI percentile 98·5 (sd 1·2)) with prediabetes.

RESULTS

Intervention participation resulted in significant reductions in weight (-1·2 %, P = 0·042), BMI and BMI percentile (-2·0 and -0·4 %, respectively, P < 0·001), body fat (-7·0 %, P = 0·025), TAG (-11·8 %, P = 0·032), total cholesterol (-5·0 %, P = 0·002), VLDL-cholesterol (-12·5 %, P = 0·029), and non-HDL-cholesterol (-6·7 %, P = 0·007). Additionally, fitness (6·4 %, P < 0·001) and intake of fruits and vegetables (42·4 %, P = 0·025) increased significantly. OxLDL decreased significantly after the intervention (51·0 (sd 14·0) v. 48·7 (sd 12·8) U/l, P = 0·022), while oxHDL trended towards a significant increase (395·2 (sd 94·6) v. 416·1 (sd 98·4) ng/ml, P = 0·056).

CONCLUSIONS

These data support the utility of lifestyle intervention to improve the atherogenic phenotype of Latino adolescents who are at high risk for developing premature CVD and type 2 diabetes.

The protective effect of apolipoprotein in models of trophoblast invasion and preeclampsia

Preeclampsia is a hypertensive disorder of pregnancy. It is associated with abnormal placentation via poor placental invasion of the uterine vasculature by trophoblast cells, leading to poor placental perfusion, oxidative stress, and inflammation, all of which are implicated in its pathogenesis. A dyslipidemia characterized by low plasma levels of high-density lipoproteins (HDL) and elevated triglycerides has been described in preeclampsia. Apolipoprotein A-I (apoA-I), a constituent of HDL is an anti-inflammatory agent. This study investigated whether apoA-I protects against hypertension and adverse placental changes in a proinflammatory cytokine (TNF-α)-induced model of preeclampsia. Further, this study investigated whether apoA-I protects against the inhibitory effect of TNF-α in a human in vitro model of trophoblast invasion. Administration of apoA-I to pregnant mice before infusion with TNF-α resulted in a significant reduction in the cytokine-induced increase in systolic blood pressure. MRI measurement of T2 relaxation, a parameter that is tissue specific and sensitive to physiological changes within tissues, showed a reversal of TNF-α-induced placental changes. Preincubation of endothelial cells with apoA-I protected against the TNF-α-induced inhibition of HTR-8/SVneo (trophoblast) cell integration into endothelial (UtMVEC) networks. These data suggest that a healthy lipid profile may affect pregnancy outcomes by priming endothelial cells in preparation for trophoblast invasion.

Arterial Segmental Vasoconstriction in Hypercholesterolaemic Patients

Regular, wave-like constriction in medium-sized arteries, arterial segmental vasoconstriction (ASV), has been observed at arteriography and described by many authors. We found ASV in arteriograms of the superficial femoral artery in 13 of 107 hypercholesterolaemic patients, enrolled in the Probucol Quantitative Regression Swedish Trial (PQRST). The arteriograms were digitized and studied with a quantitative computer-assisted technique. The frequency of ASV was higher than has been reported earlier in clinical materials, possibly because of an increased vasoreactivity in hypercholesterolaemia, as recently observed experimentally. The ASV patients were, on average, younger, had lower blood pressure and less atherosclerosis, than the non-ASV patients. ASV was not found in any of the 19 patients in the material who either had symptoms of peripheral vascular disease or arteriographically verified arterial occlusions. No significant correlations with smoking habits or serum cholesterol levels were found. A computer-based index of ASV and measurement of ASV wavelength are discussed.

Effects of oral and injected vitamin A (retinol) supplements on liver vitamin A and plasma carotenoid and cholesterol concentrations in cattle

Two experiments determined the effects of daily oral supplements of vitamin A (retinol) and injected preparations of vitamin A on liver vitamin A concentration and plasma carotenoid (PC) concentration. Vetade is an oily injectable vitamin A preparation, while Nov-a-Vit is an aqueous injectable vitamin A preparation. Angus crossbred heifers were used in experiment 1 and Angus and Simmental crossbred steers were used in experiment 2. All cattle grazed pasture but were given also 1 kg per head of pellets daily and vitamin A supplements were included in the pellets when required. In experiment 1, one group of heifers was given 1 × 106i.u. vitamin A per head daily for 31 days, while a second group in another part of the paddock was not supplemented with vitamin A. A third group of heifers grazed with this latter group and was injected with 2·5 × 106i.u. vitamin A (Vetade) three times weekly. The oral vitamin A supplement proportionately reduced plasma and liver carotenoid concentrations by 0·49 and 0·41 respectively, while increasing liver vitamin A concentration three-fold. By contrast, the Vetade failed to increase liver vitamin A concentration or to reduce liver and plasma carotenoid concentrations. In experiment 2, two groups of steers were injected twice weekly for 7 weeks with 2 × 106i.u. vitamin A as Nov-A-Vit or as Vetade. A third treatment group, grazing with these steers, received no vitamin A injection, while a fourth group grazing in a separate area of the paddock was supplemented daily with 1 × 106i.u. vitamin A per head in their diet. The injection of Nov-A-Vit and the oral vitamin A supplement decreased PC concentration by a similar amount but the increase in liver vitamin A concentration was larger for steers injected with Nov-A-Vit. Vetade injections failed to increase liver vitamin A concentration and there was no decrease in PC concentration. The plasma cholesterol concentration for the treatment groups varied over the duration of the experiment but could not be related to the vitamin A treatment or to the changes in PC concentration. These results indicate that vitamin A injections can be used to reduce PC concentration provided they increase liver vitamin A concentration.

Rare variant in scavenger receptor BI raises HDL cholesterol and increases risk of coronary heart disease

Scavenger receptor BI (SR-BI) is the major receptor for high-density lipoprotein (HDL) cholesterol (HDL-C). In humans, high amounts of HDL-C in plasma are associated with a lower risk of coronary heart disease (CHD). Mice that have depleted Scarb1 (SR-BI knockout mice) have markedly elevated HDL-C levels but, paradoxically, increased atherosclerosis. The impact of SR-BI on HDL metabolism and CHD risk in humans remains unclear. Through targeted sequencing of coding regions of lipid-modifying genes in 328 individuals with extremely high plasma HDL-C levels, we identified a homozygote for a loss-of-function variant, in which leucine replaces proline 376 (P376L), in SCARB1, the gene encoding SR-BI. The P376L variant impairs posttranslational processing of SR-BI and abrogates selective HDL cholesterol uptake in transfected cells, in hepatocyte-like cells derived from induced pluripotent stem cells from the homozygous subject, and in mice. Large population-based studies revealed that subjects who are heterozygous carriers of the P376L variant have significantly increased levels of plasma HDL-C. P376L carriers have a profound HDL-related phenotype and an increased risk of CHD (odds ratio = 1.79, which is statistically significant).

Rapamycin Promotes the Autophagic Degradation of Oxidized Low-Density Lipoprotein in Human Umbilical Vein Endothelial Cells

BACKGROUND/AIMS

Oxidized low-density lipoprotein (ox-LDL) has been extensively implicated in the initiation of atherosclerosis. Our previous studies reported that ox-LDL could activate autophagy in human umbilical vein endothelial cells (HUVECs). Because of this, subsequent studies were designed to elucidate the possible role of the autophagic inducer, rapamycin, on ox-LDL degradation in endothelial cells.

METHODS

Intracellular cholesterol content was measured using a tissue total cholesterol assay kit. ox-LDL trafficking within endothelial cells was analyzed by flow cytometry. Levels of proteins involved in the autophagic process, microtubule-associated protein 1 light chain 3 (MAP1-LC3), lysosome-associated membrane protein 1 (LAMP1), Beclin 1 and p62, were assessed by Western blot analysis.

RESULTS

We discovered that rapamycin could decrease the ox-LDL content in HUVECs at the 3-hour time point. Rapamycin also mediated an obvious increase in Dil-labeled ox-LDL (Dil-ox-LDL)/LC3 and Dil-ox-LDL/LAMP1 co-localization, which was inhibited by 3-methyladenine (3-MA), an autophagic inhibitor. In addition, significant co-localization of LC3 and LAMP1 occurred in cells pretreated with rapamycin. In the presence of rapamycin, p62 levels were reduced, and autophagic flux was enhanced.

CONCLUSION

These data demonstrate that the activation of the autophagy-lysosome pathway by rapamycin may accelerate ox-LDL degradation.

Oxidized LDL induces phosphorylation of non-muscle myosin IIA heavy chain in macrophages

Oxidized LDL (oxLDL) performs critical roles in atherosclerosis by inducing macrophage foam cell formation and promoting inflammation. There have been reports showing that oxLDL modulates macrophage cytoskeletal functions for oxLDL uptake and trapping, however, the precise mechanism has not been clearly elucidated. Our study examined the effect of oxLDL on non-muscle myosin heavy chain IIA (MHC-IIA) in macrophages. We demonstrated that oxLDL induces phosphorylation of MHC-IIA (Ser1917) in peritoneal macrophages from wild-type mice and THP-1, a human monocytic cell line, but not in macrophages deficient for CD36, a scavenger receptor for oxLDL. Protein kinase C (PKC) inhibitor-treated macrophages did not undergo the oxLDL-induced MHC-IIA phosphorylation. Our immunoprecipitation revealed that oxLDL increased physical association between PKC and MHC-IIA, supporting the role of PKC in this process. We conclude that oxLDL via CD36 induces PKC-mediated MHC-IIA (Ser1917) phosphorylation and this may affect oxLDL-induced functions of macrophages involved in atherosclerosis.

Plasma Lipids and Lipoproteins in Friedreich's Ataxia and Familial Spastic Ataxia — Evidence for an Abnormal Composition of High Density Lipoproteins

A systematic study of plasma lipids and lipoproteins was carried out in II cases of Friedreich's ataxia and 6 cases of familial spastic ataxia (Charlevoix-Saguenay disease) using II healthy normolipidemic volunteers of comparable age and sex as controls. No differences were noted in the fatty acid profile of the total lipid fraction, in the total cholesterol and phospholipids or in the percentage distribution of the individual phospholipid classes. The triglycerides were significantly higher in Friedreich's ataxia, but remained within the normal range. Although no systematic abnormalities could be detected in the electrophoretic pattern of plasma lipoproteins or in the apolipoprotein profile on polyacrylamide gel electrophoresis, major differences were found in the high density lipoprotein (HDL) fraction. Their total amount was reduced and their composition was abnormal in both neurological diseases. In Friedreich patients, the relative proportion of cholesterol and triglycerides was increased while the relative protein content was greatly reduced. In Charlevoix disease, a similar abnormality was seen except for the excess of triglycerides. The proportion of phospholipids in HDL was the same in the three groups of patients. In addition, the low density lipoprotein (LDL) fraction was slightly reduced in both diseases. This anomaly of the HDL fraction could indicate that the HDL apolipoprotein moiety has a greater affinity for cholesterol and triglycerides in Friedreich's ataxia than its normal counterpart.

HDL-bound sphingosine 1-phosphate acts as a biased agonist for the endothelial cell receptor S1P1 to limit vascular inflammation

The sphingosine 1-phosphate receptor 1 (S1P1) is abundant in endothelial cells, where it regulates vascular development and microvascular barrier function. In investigating the role of endothelial cell S1P1 in adult mice, we found that the endothelial S1P1 signal was enhanced in regions of the arterial vasculature experiencing inflammation. The abundance of proinflammatory adhesion proteins, such as ICAM-1, was enhanced in mice with endothelial cell-specific deletion of S1pr1 and suppressed in mice with endothelial cell-specific overexpression of S1pr1, suggesting a protective function of S1P1 in vascular disease. The chaperones ApoM(+)HDL (HDL) or albumin bind to sphingosine 1-phosphate (S1P) in the circulation; therefore, we tested the effects of S1P bound to each chaperone on S1P1 signaling in cultured human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to ApoM(+)HDL-S1P, but not to albumin-S1P, promoted the formation of a cell surface S1P1-β-arrestin 2 complex and attenuated the ability of the proinflammatory cytokine TNFα to activate NF-κB and increase ICAM-1 abundance. Although S1P bound to either chaperone induced MAPK activation, albumin-S1P triggered greater Gi activation and receptor endocytosis. Endothelial cell-specific deletion of S1pr1 in the hypercholesterolemic Apoe(-/-) mouse model of atherosclerosis enhanced atherosclerotic lesion formation in the descending aorta. We propose that the ability of ApoM(+)HDL to act as a biased agonist on S1P1 inhibits vascular inflammation, which may partially explain the cardiovascular protective functions of HDL.

Antioxidant effects of 14 Chinese traditional medicinal herbs against human low-density lipoprotein oxidation

The relationship between the antioxidant activities and inhibitory effect of 14 Chinese medicinal herbs against oxidized low-density lipoprotein (LDL) formation was evaluated. Prolongation of the lag phase of LDL oxidation depended on the concentration of the herbs. The concentration of each herb that was able to prolong the lag time by about two-fold was calculated and expressed as doubling-time concentration. The lower the doubling-time concentration, the stronger the inhibitory effect exhibited toward LDL oxidation. Among them, Chrysanthemi Flos (Chrysanthemum morifolium ramat; 甘菊花 gān jú huā), Crataegi Fructus (Crataegus pinnatifida Bge. var. major N.E.Br.; 山楂 shān zhā), and Roselle (Hibiscus sabdariffa Linn.; 洛神 luò shén) showed significant inhibitory effects. Correlation coefficients between doubling-time concentration and radical-scavenging activities were high; the total phenolic content was also high. In conclusion, phenolic compounds contributed not only to antioxidant activities, but also to the inhibitory effect against LDL oxidation. Chrysanthemi Flos, Crataegi Fructus, and H. sabdariffa, with lower doubling-time concentrations, could be potent phytochemical agents to reduce LDL oxidation and prevent the progression of atherosclerosis.

Comparison of various formulae for estimating low-density lipoprotein cholesterol by a combination of ages and genders in Taiwanese adults

Background

The accuracy and precision of the Friedewald formula for estimating low-density lipoprotein cholesterol (LDL-C) is questionable. Although other formulae have been developed, only a few studies compare them. Thus, we compared the efficiencies of various formulae, based on the age and gender of adults, to determine which ones yield more accurate estimations in terms of mean squared error, and which formulae underestimated and overestimated LDL-C performance.

Methods

This study compares various formulae in terms of mean squared error (MSE), as well as underestimation and overestimation of LDL-C concentrations, using subjects of various ages and both genders. Six groups were examined in this study based on age and gender: males 20–44 years old, 45–64, and 65 and above, and females in the same three age ranges.

Results

The results show that the Friedewald formula has relatively low accuracy, and while its performance among older (aged 45 and above) women with triglyceride concentrations ≤ 400 mg/dL is better than that with other groups, it is still more inaccurate than the other formulae. In terms of prediction errors and mean squared errors, Tsai’s formula (TF) and a calibrated TF provide the most accurate results with regard to the LDL-C concentration. Moreover, based on a cross-validation of age and gender, these two formulae provide highly accurate results for the LDL-C concentrations of all the studied groups, except for women aged 20–44 years.

Conclusions

Based on the experimental results, this study provides a set of benchmarks for the formulae used in LDL-C tests when considering the factors of age and gender. Therefore, it is a valuable method for providing formula benchmarking.

Effect of Ascorbate on Acrolein Modification of Very Low Density Lipoprotein and Uptake of Oxidized Apolipoprotein E by Hepatocytes

Acrolein modification of apolipoprotein (apo) E in human very low density lipoprotein (VLDL) was suppressed by ascorbate. Acrolein-modified apoE in VLDL was not taken up by human hepatoma cell whereas unmodified apoE in the presence of ascorbate was taken up. These results suggest that ascorbate can play an important role in maintaining proper lipoprotein metabolism by the antioxidant effect.

Oxidative modification of lipoproteins

Lipoproteins consist of lipids and apolipoproteins that have functional roles in lipid metabolism. It has been suggested that oxidation of lipoproteins by reactive oxygen species (ROS) may be involved in the inception of various diseases. In particular, the relationship between low-density lipoprotein (LDL) oxidation and atherosclerosis has been studied in great detail. The main target molecules of lipoprotein oxidation are polyunsaturated fatty acid residues of lipids and apolipoproteins. Extensive investigations have characterized oxidative modifications of apolipoprotein B100 (apo B100) in LDL. Furthermore, modifications of apo B100 by oxidized lipids have been confirmed in oxidized LDL and atherosclerotic lesions using immunological techniques. In this chapter, characteristics and oxidation mechanisms of lipoproteins by ROS are described from in vitro and in vivo studies. Oxidative modifications of apo B100 by lipid hydroperoxides, major products of lipid peroxidation at the early stage, are principally reported.

Probucol inhibits the initiation of atherosclerosis in cholesterol-fed rabbits

BACKGROUND

Probucol and statin are often prescribed for treating atherosclerosis. These two drugs exhibit different mechanisms but it is unknown whether they have the same anti-atherogenic properties. In the current study, we examined whether these two drugs at optimal doses could inhibit the initiation of atherosclerosis in cholesterol-fed rabbits in the same way.

METHODS

New Zealand White rabbits were fed a cholesterol-rich diet for 5 weeks to produce the early-stage lesions of atherosclerosis. Drug-treated rabbits were administered either probucol or atorvastatin and serum lipids and aortic atherosclerotic lesions were compared with those in a control group.

RESULTS

Atorvastatin treatment significantly reduced serum total cholesterol levels while probucol treatment led to significant reduction of high-density lipoprotein cholesterol levels without changing total cholesterol levels compared with those in the control group. Compared with the control, probucol treatment led to 65% (p < 0.01) reduction while atorvastatin treatment led to 23% (p = 0.426) reduction of the aortic lesion area. Histological and immunohistochemical analyses revealed that the lesions of the probucol-treated group were characterized by remarkable reduction of monocyte adherence to endothelial cells and macrophage accumulation in the intima compared with those of both atorvastatin and control groups. Furthermore, low-density lipoprotein (LDL) isolated from the probucol group exhibited prominent anti-oxidative reaction, which was not present in LDL isolated from either the atorvastatin-treated or the control group.

CONCLUSIONS

This study suggests that probucol inhibits the initiation of atherosclerosis by reducing monocyte adherence and infiltration into the subintima. Anti-oxidization of LDL by probucol protects more effectively against early-stage lesion formation than statin-mediated lipid-lowering effects.

Myeloperoxidase, paraoxonase-1, and HDL form a functional ternary complex

Myeloperoxidase (MPO) and paraoxonase 1 (PON1) are high-density lipoprotein-associated (HDL-associated) proteins mechanistically linked to inflammation, oxidant stress, and atherosclerosis. MPO is a source of ROS during inflammation and can oxidize apolipoprotein A1 (APOA1) of HDL, impairing its atheroprotective functions. In contrast, PON1 fosters systemic antioxidant effects and promotes some of the atheroprotective properties attributed to HDL. Here, we demonstrate that MPO, PON1, and HDL bind to one another, forming a ternary complex, wherein PON1 partially inhibits MPO activity, while MPO inactivates PON1. MPO oxidizes PON1 on tyrosine 71 (Tyr71), a modified residue found in human atheroma that is critical for HDL binding and PON1 function. Acute inflammation model studies with transgenic and knockout mice for either PON1 or MPO confirmed that MPO and PON1 reciprocally modulate each other's function in vivo. Further structure and function studies identified critical contact sites between APOA1 within HDL, PON1, and MPO, and proteomics studies of HDL recovered from acute coronary syndrome (ACS) subjects revealed enhanced chlorotyrosine content, site-specific PON1 methionine oxidation, and reduced PON1 activity. HDL thus serves as a scaffold upon which MPO and PON1 interact during inflammation, whereupon PON1 binding partially inhibits MPO activity, and MPO promotes site-specific oxidative modification and impairment of PON1 and APOA1 function.

LC-MS/MS analysis of canine lipoproteins fractionated using the ultracentrifugation-precipitation method

Due to the lack of a gold standard method in canine lipoprotein analysis, it is unclear whether canine high-density lipoprotein (HDL) and low-density lipoprotein (LDL) can be accurately evaluated by the lipoprotein analysis methods used for dogs. This study investigated whether the ultracentrifugation-precipitation (U-P) method was suitable as a gold standard method for analyzing canine lipoprotein. First, the U-P method was compared with a gel permeation high-performance liquid chromatography system (GP-HPLC). The concentrations of canine HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) determined by the U-P method correlated closely with those determined by GP-HPLC. However, the canine HDL-C concentration determined by the U-P method was lower than that determined by GP-HPLC, and the canine LDL-C concentration determined by the U-P method was higher than that determined by GP-HPLC. This study showed that some canine HDL could be precipitated with heparin manganese chloride solution. Second, the HDL and LDL fractions separated by the U-P method were analyzed by LC-MS/MS. The HDL fraction was found to contain only apolipoprotein A-I, which is an apolipoprotein of HDL, whereas the LDL fraction contained both apolipoprotein A-I and apolipoprotein B-100, which is an apolipoprotein of LDL. This data showed that a certain lipoprotein that includes apolipoprotein A-I might precipitate with canine LDL when using heparin manganese chloride solution. These results indicated that the U-P method is not currently a gold standard method for analyzing canine lipoproteins.

Serum albumin acts as a shuttle to enhance cholesterol efflux from cells

An important mechanism contributing to cell cholesterol efflux is aqueous transfer in which cholesterol diffuses from cells into the aqueous phase and becomes incorporated into an acceptor particle. Some compounds can enhance diffusion by acting as shuttles transferring cholesterol to cholesterol acceptors, which act as cholesterol sinks. We have examined whether particles in serum can enhance cholesterol efflux by acting as shuttles. This task was accomplished by incubating radiolabeled J774 cells with increasing concentrations of lipoprotein-depleted sera (LPDS) or components present in serum as shuttles and a constant amount of LDL, small unilamellar vesicles, or red blood cells (RBC) as sinks. Synergistic efflux was measured as the difference in fractional efflux in excess of that predicted by the addition of the individual efflux values of sink and shuttle alone. Synergistic efflux was obtained when LPDS was incubated with cells and LDL. When different components of LPDS were used as shuttles, albumin produced synergistic efflux, while apoA-I did not. A synergistic effect was also obtained when RBC was used as the sink and albumin as shuttle. The previously observed negative association of albumin with coronary artery disease might be linked to reduced cholesterol shuttling that would occur when serum albumin levels are low.

Apolipoprotein E-mediated cell cycle arrest linked to p27 and the Cox2-dependent repression of miR221/222

OBJECTIVE

In addition to its effects on cholesterol levels, apoE3 has lipid-independent effects that contribute to cardiovascular protection; one of these effects is the ability to inhibit cell cycling in VSMCs. The goal of this study was to identify and characterize cell cycle-regulatory mechanisms responsible for the anti-mitogenic effect of apoE.

METHODS AND RESULTS

Primary VSMCs were stimulated with serum in the absence or presence of apoE3. apoE3 upregulated expression of the cdk inhibitor, p27(kip1), in primary VSMCs, and this effect required Cox2 and activation of PGI(2)-IP signaling. The microRNA family, miR221/222 has recently been identified as a post-translational regulator of p27, and apoE3 inhibited miR221/222 expression in a Cox2- and PGI(2)/IP-dependent manner. Moreover, reconstituted miR222 expression was sufficient to override the effects of apoE on p27 expression and S phase entry. The ability to repress expression of miR221/222 is shared by apoE3-containing HDL but is absent from apoA-1, LDL and apoE-depleted HDL. All three apoE isoforms regulate miR221/222, and the effect is independent of the C-terminal lipid-binding domain. miR221/222 levels are increased in the aortae of apoE3-null mice and reduced when apoE3 expression is reconstituted by adeno-associated virus infection. Thus, regulation of miR221/222 by apoE3 occurs in vivo as well as in vitro.

CONCLUSIONS

ApoE inhibits VSMC proliferation by regulating p27 through miR221/222. Control of cell cycle-regulatory microRNAs adds a new dimension to the spectrum of cardiovascular protective effects afforded by apoE and apoE-HDL.

Cardiovascular protection by ApoE and ApoE-HDL linked to suppression of ECM gene expression and arterial stiffening

Arterial stiffening is a risk factor for cardiovascular disease, but how arteries stay supple is unknown. Here, we show that apolipoprotein E (apoE) and apoE-containing high-density lipoprotein (apoE-HDL) maintain arterial elasticity by suppressing the expression of extracellular matrix genes. ApoE interrupts a mechanically driven feed-forward loop that increases the expression of collagen-I, fibronectin, and lysyl oxidase in response to substratum stiffening. These effects are independent of the apoE lipid-binding domain and transduced by Cox2 and miR-145. Arterial stiffness is increased in apoE null mice. This stiffening can be reduced by administration of the lysyl oxidase inhibitor BAPN, and BAPN treatment attenuates atherosclerosis despite highly elevated cholesterol. Macrophage abundance in lesions is reduced by BAPN in vivo, and monocyte/macrophage adhesion is reduced by substratum softening in vitro. We conclude that apoE and apoE-containing HDL promote healthy arterial biomechanics and that this confers protection from cardiovascular disease independent of the established apoE-HDL effect on cholesterol.

Measurement of LDL-C after treatment with the CETP inhibitor anacetrapib

Estimation of low-density lipoprotein cholesterol (LDL-C) using the Friedewald (FR) formula is often inaccurate when triglycerides are elevated or VLDL particle composition is altered. We hypothesized that LDL-C estimation by the FR formula and other measurement methods might also be inaccurate in individuals treated with a cholesteryl ester transfer protein (CETP) inhibitor. An assay comparison study was conducted using pre and posttreatment serum samples from 280 of the 811 patients treated with the CETP inhibitor anacetrapib in the DEFINE study (determining the efficacy and tolerability of CETP inhibition with anacetrapib). After 24 weeks of treatment with anacetrapib, mean LDL-C values by FR formula, Roche direct method (RDM) and Genzyme direct method (GDM) deviated from that measured by the β-quantification (BQ) reference method by -12.2 ± 7.5, -10.2 ± 6.6, -10.8 ± 8.8 mg/dl, respectively. After treatment with anacetrapib, the FR formula and detergent-based direct methods provided lower LDL-C values than those obtained by the BQ reference method. The bias by the FR formula appeared to be due to an overestimation of VLDL-C by the TG/5 component of the formula. Evaluation of the clinical significance of these findings awaits comprehensive lipid and cardiovascular outcome data from ongoing Phase III clinical studies of anacetrapib.

Oxidized LDL/CD36 interaction induces loss of cell polarity and inhibits macrophage locomotion

Cell polarization is essential for migration and the exploratory function of leukocytes. However, the mechanism by which cells maintain polarity or how cells revert to the immobilized state by gaining cellular symmetry is not clear. Previously we showed that interaction between oxidized low-density lipoprotein (oxLDL) and CD36 inhibits macrophage migration; in the current study we tested the hypothesis that oxLDL/CD36-induced inhibition of migration is the result of intracellular signals that regulate cell polarity. Live cell imaging of macrophages showed that oxLDL actuated retraction of macrophage front end lamellipodia and induced loss of cell polarity. Cd36 null and macrophages null for Vav, a guanine nucleotide exchange factor (GEF), did not show this effect. These findings were caused by Rac-mediated inhibition of nonmuscle myosin II, a cell polarity determinant. OxLDL induced dephosphorylation of myosin regulatory light chain (MRLC) by increasing the activity of Rac. Six-thioguanine triphosphate (6-thio-GTP), which inhibits Vav-mediated activation of Rac, abrogated the effect of oxLDL. Activation of the Vav-Rac-myosin II pathway by oxidant stress may induce trapping of macrophages at sites of chronic inflammation such as atherosclerotic plaque.

Identification of differentially expressed genes and pathways for intramuscular fat deposition in pectoralis major tissues of fast-and slow-growing chickens

Background

Intramuscular fat (IMF) is one of the important factors influencing meat quality, however, for chickens, the molecular regulatory mechanisms underlying this trait have not yet been determined. In this study, a systematic identification of candidate genes and new pathways related to IMF deposition in chicken breast tissue has been made using gene expression profiles of two distinct breeds: Beijing-you (BJY), a slow-growing Chinese breed possessing high meat quality and Arbor Acres (AA), a commercial fast-growing broiler line.

Results

Agilent cDNA microarray analyses were conducted to determine gene expression profiles of breast muscle sampled at different developmental stages of BJY and AA chickens. Relative to d 1 when there is no detectable IMF, breast muscle at d 21, d 42, d 90 and d 120 (only for BJY) contained 1310 differentially expressed genes (DEGs) in BJY and 1080 DEGs in AA. Of these, 34–70 DEGs related to lipid metabolism or muscle development processes were examined further in each breed based on Gene Ontology (GO) analysis. The expression of several DEGs was correlated, positively or negatively, with the changing patterns of lipid content or breast weight across the ages sampled, indicating that those genes may play key roles in these developmental processes. In addition, based on KEGG pathway analysis of DEGs in both BJY and AA chickens, it was found that in addition to pathways affecting lipid metabolism (pathways for MAPK & PPAR signaling), cell junction-related pathways (tight junction, ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton), which play a prominent role in maintaining the integrity of tissues, could contribute to the IMF deposition.

Conclusion

The results of this study identified potential candidate genes associated with chicken IMF deposition and imply that IMF deposition in chicken breast muscle is regulated and mediated not only by genes and pathways related to lipid metabolism and muscle development, but also by others involved in cell junctions. These findings establish the groundwork and provide new clues for deciphering the molecular mechanisms underlying IMF deposition in poultry. Further studies at the translational and posttranslational level are now required to validate the genes and pathways identified here.

Effects of a meal rich in 1,3-diacylglycerol on postprandial cardiovascular risk factors and the glucose-dependent insulinotropic polypeptide in subjects with high fasting triacylglycerol concentrations

It was previously reported that compared to triacylglycerol (TAG) oil, diacylglycerol (DAG) oil improves postprandial lipid response. However, the effects of DAG oil on postprandial hyperglycemia and incretin response have not yet been determined. In this study, the effects of DAG oil on both postprandial hyperlipidemia and hyperglycemia and the response to the glucose-dependent insulinotropic polypeptide (GIP) were studied. This randomized, double-blind, crossover study analyzed data for 41 individuals with high fasting triacylglycerol concentrations. The subjects ingested test meals (30.3 g of protein, 18.6 g of fat, and 50.1 g of carbohydrate) containing 10 g of DAG oil (DAG meal) or TAG oil (TAG meal) after fasting for at least 12 h. Blood samples were collected prior to and 0.5, 2, 3, 4, and 6 h after ingestion of the test meal. Postprandial TAG concentrations were significantly lower after the DAG meal compared with the TAG meal. Postprandial TAG, insulin, and GIP concentrations were significantly lower after the DAG meal compared with the TAG meal in 26 subjects with fasting serum TAG levels between 1.36 and 2.83 mmol/L. DAG-oil-based meals, as a replacement for TAG oil, may provide cardiovascular benefits in high-risk individuals by limiting lipid and insulin excursions.

Comparison of breast muscle meat quality in 2 broiler breeds

On the basis of meat quality traits, muscle fiber characteristics, and nutrient components and contents in chickens at market age, 120-d-old Beijing-you (BJY) chickens (the Chinese local breed) had distinct breast muscle features when compared with 42-d-old Arbor Acres (AA) chickens (the genetically improved broiler line). The phospholipid (P < 0.05) and essential fatty acid (P < 0.05) contents in BJY chickens were significantly higher than those in AA chickens. No differences (P > 0.05) were found between the breeds in the contents of polyunsaturated fatty acids, unsaturated fatty acids, protein, or amino acids. Breast muscle fiber diameter was significantly smaller (~55.76%) and fiber density was higher (~174.86%) in BJY chickens than in AA chickens (P < 0.05). In this study, breast muscle from 120-d-old BJY chickens was judged to have better quality of phospholipids and essential fatty acid contents and muscle fiber characteristics than breast muscle from 42-d-old AA chickens.

Efficient in vivo delivery of siRNA into brain capillary endothelial cells along with endogenous lipoprotein

The brain capillary endothelial cell (BCEC) is a major functional component of the blood-brain barrier and is an underlying factor in the pathophysiology of various diseases, including brain ischemia, multiple sclerosis, and neurodegenerative disorders. We examined gene silencing in BCECs by using endogenous lipoprotein to introduce short-interfering RNA (siRNA) in vivo. A cholesterol-conjugated 21/23-mer siRNA targeting organic anion transporter 3 (OAT3) mRNA (Chol-siOAT3) was intravenously injected into mice after its incorporation into extracted endogenous lipoproteins. Chol-siOAT3 was not delivered to neurons or glia, but was successfully delivered into BCECs and resulted in a significant reduction of OAT3 mRNA levels when injected after its incorporation into high-density lipoprotein (HDL). Efficient delivery was not achieved, however, when Chol-siOAT3 was injected without any lipoproteins, or after its incorporation into low-density lipoprotein (LDL). Investigations in apolipoprotein E (ApoE)-deficient and LDL receptor (LDLR)-deficient mice revealed that the uptake of HDL-containing Chol-siOAT3 was mainly mediated by ApoE and LDLR in mice. These findings indicate that siRNA can be delivered into BCECs in vivo by using endogenous lipoprotein, which could make this strategy useful as a new gene silencing therapy for diseases involving BCECs.

Adiponectin and sE-selectin Concentrations in Relation to Inflammation in Obese Type 2 Diabetic Patients With Coronary Heart Disease

Adipose tissue can release proinflammatory mediators, namely C-reactive protein (CRP), interleukin 1β (IL-1β), and monocyte chemotactic protein 1 (MCP-1), contributing to vascular injury and insulin resistance (IR). Other mediators namely, adiponectin and nitric oxide (NO) are protective. We enrolled type 2 diabetes mellitus (T2DM) obese male patients without coronary heart disease ([CHD] group II, n = 25) and T2DM obese patients with CHD (group III, n = 25). They were compared with 20 age- and body mass index (BMI)-matched nondiabetic control males (group I). Fasting blood glucose (FBG), glycated hemoglobin (HbA1c%), lipids, insulin, malondialdehyde ([MDA]; lipid peroxidation product), NO, high-sensitivity CRP (hsCRP), IL-1β, MCP-1, adiponectin as well as sE-selectin concentration were significantly different in patients with T2DM and CHD compared with patients without CHD and nondiabetic controls ( P = .01). There was a significant negative correlation between adiponectin and E-selectin ( P = .0001). Adipose tissue in T2DM obese patients may contribute to the pathogenesis of CHD.

Effect of Bile on Absorption of Mepitiostane by the Lymphatic System in Rats

The effects of bile and site of gastrointestinal absorption on the lymphatic absorption of the highly lipophilic drug, mepitiostane were examined using thoracic duct-cannulated rats. The lymphatic absorption from the small intestine was very small in the absence of bile compared with that when bile was present. The lymphatic absorption was greatest when drug was administered to the upper small intestine with bile, was smaller for the lower regions of the small intestine, and was negligible for the stomach and the large intestine. A correlation was observed between the extent of lymphatic absorption and the secretion of chylomicron and very low density lipoproteins after administration to various regions with or without bile. The portal absorption data of mepitiostane confirmed that site specificity occurs in the partition of drug between blood and lymph.

High-density lipoprotein facilitates in vivo delivery of α-tocopherol-conjugated short-interfering RNA to the brain

We originally reported the use of vitamin E (α-tocopherol) as an in vivo vector of short-interfering RNA (siRNA) to the liver. Here, we apply our strategy to the brain. By combining high-density lipoprotein (HDL) as a second carrier with α-tocopherol-conjugated siRNA (Toc-siRNA) in the brain, we achieved dramatic improvement of siRNA delivery to neurons. After direct intracerebroventricular (ICV) infusion of Toc-siRNA/HDL for 7 days, extensive and specific knock-down of a target gene, β-site amyloid precursor protein cleaving enzyme 1 (BACE1), was observed in both mRNA and protein levels, especially in the cerebral cortex and hippocampus. This new delivery method achieved a much more prominent down-regulation effect than conventional silencing methods of the brain gene, i.e., ICV infusion of nonconjugated siRNA or oligonucleotides. With only 3 nmol Toc-siRNA with HDL, BACE1 mRNA in the parietal cortex could be reduced by ∼ 70%. We suppose that this dramatic improvement of siRNA delivery to the brain is due to the use of lipoprotein receptor-mediated endocytosis because the silencing efficiency was significantly increased by binding of Toc-siRNA to the lipoprotein, and in contrast, was clearly decreased in lipoprotein-receptor knockout mice. These results suggest exogenous siRNA could be used clinically for otherwise incurable neurological diseases.