bluuebunny/crossref_metadata_2025 huggingface dataset:
Ligand Specificity of LOX-1, a Novel Endothelial Receptor for Oxidized Low Density Lipoprotein
Authors: Moriwaki Hideaki , Kume Noriaki , Sawamura Tatsuya , Aoyama Takuma , Hoshikawa Hajime , Ochi Hiroshi , Nishi Eiichiro , Masaki Tomoh , Kita Toru
Published: June 2011

Abstract
—Endothelial dysfunction, or activation, elicited by oxidized low density lipoprotein (Ox-LDL) and its lipid constituents has been shown to play a key role in the pathogenesis of atherosclerosis. We recently have identified a novel receptor for Ox-LDL-designated lectin-like Ox-LDL receptor (LOX-1) in vascular endothelial cells. To examine ligand specificity of LOX-1, we established CHO cell lines stably expressing both human and bovine LOX-1 (LOX-1-CHO). LOX-1-CHO bound and degraded
125
I-labeled Ox-LDL but did not significantly degrade
125
I-labeled acetylated LDL (Ac-LDL). Fucoidin and maleylated BSA (M-BSA), which inhibit
125
I-Ox-LDL binding to class A scavenger receptors, did not inhibit
125
I-Ox-LDL binding or degradation in LOX-1-CHO. Polyinosinic acid and carrageenan, in contrast, significantly reduced
125
I-Ox-LDL binding to LOX-1-CHO by 62% and 60%, respectively. Delipidated and untreated
125
I-Ox-LDL were bound and degraded equally in LOX-1-CHO; furthermore, excess amounts of unlabeled, delipidated Ox-LDL inhibited binding and degradation of untreated
125
I-Ox-LDL. Taken together, LOX-1 is a receptor for Ox-LDL but not for Ac-LDL. LOX-1 recognizes protein moiety of Ox-LDL, and its ligand specificity is distinct from other receptors for Ox-LDL, including class A and B scavenger receptors.
Impaired Insulin-Stimulated Glucose Oxidation and Free Fatty Acid Suppression in Patients with Familial Combined Hyperlipidemia
Authors: Karjalainen Leena , Pihlajamäki Jussi , Karhapää Pauli , Laakso Markku
Published: June 2011

Abstract—Familial combined hyperlipidemia (FCHL) is characterized by hyperlipidemia and insulin resistance, but intracellular defect in insulin action is unknown. Therefore, we investigated insulin action by applying the hyperinsulinemic euglycemic clamp technique with indirect calorimetry in 58 FCHL family members (28 with FCHL; 30 without dyslipidemia; aged 49±12 years; body mass index [BMI], 25.2±4.0 kg/m2) and in 72 healthy control subjects (aged 54±6 years; BMI, 26.3±3.1 kg/m2). In the fasting state, FCHL patients had higher levels of total cholesterol, total triglycerides, and apolipoprotein B than control subjects (P<0.001 after adjustment for gender, age, and BMI). During the euglycemic clamp, FCHL patients had lower rates of glucose oxidation (15.93±3.55 versus 19.65±4.60 μmol/kg/min;P=0.001) and higher rates of lipid oxidation (0.15±0.13 versus 0.01±0.25 mg/kg/min;P=0.024), as well as higher levels of serum-free fatty acids (FFA) (0.24±0.17 versus 0.06±0.06 mmol/L;P<0.001) compared with those of control subjects. Relatives without dyslipidemia differed similarly from control subjects with respect to rates of glucose and lipid oxidation and FFA suppression during the hyperinsulinemic clamp. In FCHL family members, during the euglycemic clamp FFAs correlated negatively with the rates of glucose oxidation (P<0.001) but not with the rates of glucose nonoxidation (P=0.408). In FCHL family members without dyslipidemia and in control subjects, FFAs during the clamp correlated positively with levels of total triglycerides (P<0.001) and very low density lipoprotein cholesterol (P=0.008). We conclude that in patients with FCHL, and also in their first-degree relatives, insulin’s suppressive effect on FFA levels is impaired, which may precede dyslipidemia in FCHL.
Matrix Metalloproteinase-2 Production and Its Binding to the Matrix Are Increased in Abdominal Aortic Aneurysms
Authors: Davis Valerie , Persidskaia Raisa , Baca-Regen Lisa , Itoh Yoshifumi , Nagase Hideaki , Persidsky Yuri , Ghorpade Anuja , Baxter B. Timothy
Published: June 2011

Abstract—Degradation of the elastic media is a hallmark of abdominal aortic aneurysms (AAAs). We examined the expression of 2 elastolytic matrix metalloproteinases (MMPs), MMP-2 and MMP-9, in AAA aortic tissues compared with those from atherosclerotic occlusive disease (AOD) and nondiseased control tissues. Quantitative competitive reverse transcription–polymerase chain reaction and gelatin zymography showed increased MMP-9 mRNA and protein in both AAA and AOD tissues compared with those in control tissue, but there was no significant difference between AAA and AOD. In contrast, MMP-2 mRNA and protein levels were significantly higher in AAA than in AOD or control tissues. Sequential extraction of the MMPs from the aortic tissue with a physiological salt solution, 2% dimethylsulfoxide (DMSO), and 10 mol/L urea showed that large amounts of MMP-2 and MMP-9 were bound to the matrix. The most conspicuous finding was that the levels of MMP-2 were significantly elevated in the DMSO fraction in AAA tissues compared with AOD and control tissues. In addition, a large portion of MMP-2 found in the DMSO and urea fractions was in the active 62-kDa form, indicating that the precursor of MMP-2 in AAA is largely activated locally and binds to the tissue matrix tightly. By immunolocalization, MMP-9 was found to be primarily produced by macrophages and MMP-2 by mesenchymal cells. The production of MMP-2 was prominent when mesenchymal cells were surrounded by inflammatory cells, suggesting paracrine modulation of MMP-2 expression in AAAs. These observations emphasize that MMP-2 participates in the progression of AAAs by degrading aortic tissue matrix components.
Combination of Fosinopril and Pravastatin Decreases Platelet Response to Thrombin Receptor Agonist in Monkeys
Authors: Hale L. Paulette , Craver Karen T. , Berrier Alan M. , Sheffield Matthew V. , Case L. Douglas , Owen John
Published: June 2011

Abstract
—Both angiotensin-converting enzyme (ACE) inhibitors and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been shown to decrease cardiovascular morbidity and mortality. Results from clinical trials have suggested that HMG-CoA reductase inhibition might exert a beneficial effect independent of its lipid-lowering effect, and ACE inhibition may exert a benefit independent of blood-pressure lowering. To test the hypothesis that such an effect might be mediated by alteration in platelet reactivity, we studied 55 monkeys receiving both, 1, or neither of the ACE inhibitor fosinopril and the HMG-CoA reductase inhibitor pravastatin. Platelet responsiveness to collagen and to the thrombin receptor agonist (TRA) SFLRRN-NH
2
was determined by aggregometry. For each agonist, the maximum rate and extent of aggregation were measured for each dose, and the concentration required for half-maximal response (C
50
) was determined. Each drug, when given alone, slightly decreased the dose of agonist required to produce 50% response in the rate and extent of platelet aggregation relative to control. The combination of the 2 drugs, however, produced a significant increase in the dose of TRA required to produce 50% response in the rate and extent of aggregation relative to either drug alone or the control group. This was not true for collagen. The magnitude of the change relative to the control group, 47% for rate and 30% for extent of aggregation, could confer considerable protection by changing the threshold for thrombin-induced platelet aggregation and, thus, decrease thrombosis.
Plasma Leptin Levels
Authors: Krempler Franz , Hell Emanuel , Winkler Carmen , Breban David , Patsch Wolfgang
Published: June 2011

Abstract
—Obesity is associated with insulin resistance and other major cardiovascular risk factors. A common amino acid polymorphism at codon 972 of the insulin receptor substrate-1 (IRS-1) has been shown to interact with obesity in the expression of insulin resistance. The plasma concentration of the adipocyte-specific hormone leptin is increased in obesity and is correlated with adipose tissue mass. Because in vitro studies demonstrated inhibitory effects of leptin on insulin signaling, leptin may be involved in obesity-associated insulin resistance. To gain insight into the relationship between insulin and leptin in obesity, we studied plasma leptin levels and several cardiovascular risk factors, as well as their modification by the IRS-1 codon 972 genotype, in 156 obese individuals and 131 lean control subjects. In both groups, 10% of the subjects were heterozygous for the IRS-1 codon 972 variant. Obese individuals harboring the IRS-1 variant displayed significantly lower plasma concentrations of leptin than obese subjects without the polymorphism (means, 26.7 versus 37.8 ng/mL,
P
<0.0293). In a subgroup of obese patients, leptin mRNA abundance was measured in the adipose tissue and was significantly lower in carriers of the IRS-1 variant than in subjects with the wild-type variant (
P
<0.0291). Our data suggest that insulin signaling influences plasma leptin concentrations at the mRNA expression level and argue against leptin as a major causative factor of insulin resistance.
Improvement of Relaxation in an Atherosclerotic Artery by Gene Transfer of Endothelial Nitric Oxide Synthase
Authors: Ooboshi Hiroaki , Toyoda Kazunori , Faraci Frank M. , Lang Markus G. , Heistad Donald D.
Published: June 2011

Abstract
—Gene transfer with replication-deficient adenovirus is a useful tool to study vascular biology. We have reported that overexpression of endothelial nitric oxide (NO) in carotid arteries from normal rabbits augments vasorelaxation mediated by NO. In this study, we tested the hypothesis that adenovirus-mediated gene transfer of endothelial nitric oxide synthase (eNOS) improves impaired relaxation of atherosclerotic vessels. We used 2 replication-deficient adenoviruses: AdeNOS, which carries cDNA for eNOS, and Adβgal, which expresses β-galactosidase. Common carotid arteries from 10 New Zealand White (NZW; plasma cholesterol, 79±13 mg/dL) and 10 Watanabe heritable hyperlipidemic (WHHL; plasma cholesterol, 452±39 mg/dL) rabbits were incubated in organ culture with AdeNOS, Adβgal, or vehicle alone. Carotid arteries from WHHL rabbits had mild to moderate atherosclerotic lesions. Histochemical staining for β-galactosidase and immunohistochemistry for eNOS indicated transgene expression in the endothelium and adventitia in both NZW and WHHL rabbits. Expression of eNOS determined with Western blot analysis after incubation with AdeNOS tended to be higher in vessels from WHHL rabbits than NZW rabbits. Effects of transgene expression on vascular function were examined by recording isometric tension 1 day after transduction. After precontraction with phenylephrine, acetylcholine produced significantly less relaxation in vessels from WHHL rabbits than in vessels from NZW rabbits. Relaxation in response to acetylcholine was greater in carotid arteries from both NZW and WHHL rabbits that were transfected with AdeNOS than in vessels treated with vehicle or Adβgal. Vasorelaxation in response to acetylcholine was inhibited by
N
ω
-nitro-
l
-arginine. Responses to sodium nitroprusside were similar after treatment with vehicle alone, Adβgal, or AdeNOS in both groups of rabbits. Thus, overexpression of eNOS with an adenoviral vector improves impaired NO-mediated relaxation in atherosclerotic arteries.
Serial Changes in Body Composition Throughout Adulthood and Their Relationships to Changes in Lipid and Lipoprotein Levels
Authors: Siervogel Roger M. , Wisemandle Wayne , Maynard L. Michele , Guo Shumei S. , Roche Alex F. , Chumlea William C. , Towne Bradford
Published: June 2011

Abstract
—Few studies have examined the relationships between measures of body composition and lipid and lipoprotein levels in long-term serial data from individuals unselected for cardiovascular disease– or obesity-related variables, and none have considered such extensive serial data as used in the current study. The aim was to examine in such individuals the associations between annual changes in lipid and lipoprotein levels and concurrent changes in total body fat, fat-free mass, percent body fat, and body mass index. Serial data from 1304 examinations of 423 adult white participants in the Fels Longitudinal Study were analyzed sex-specifically in 2 age groups, 18 through 44 years and 45 to 65 years. A regressive analytic approach utilized the long-term (4 to 20 years) serial data of individuals. Annual changes in adiposity, independent of levels of lean tissue changes, before and after age 45 for men and women were significantly correlated with corresponding annual changes in cholesterol and low density lipoprotein cholesterol. In men before age 45, changes in triglycerides and high density lipoprotein cholesterol were also significantly associated with changes in adiposity, with the relationship remaining after age 45 in high density lipoprotein cholesterol. Increases in adiposity in individuals are associated with changes in lipid and lipoprotein levels in the direction of increased risk for cardiovascular disease. Adult levels of total cholesterol and low density lipoprotein cholesterol across age and sex and high density lipoprotein cholesterol in men are responsive to changes in adiposity, independent of initial adiposity or lipid and lipoprotein levels.
Charge Heterogeneity of LDL in Asymptomatic Hypercholesterolemic Men Is Related to Lipid Parameters and Variations in the ApoB and CIII Genes
Authors: Védie Benoit , Jeunemaitre Xavier , Mégnien Jean Louis , Myara Isaac , Trébeden Hélène , Simon Alain , Moatti Nicole
Published: June 2011

Abstract—This study was carried out to examine the relationship between the charge on low density lipoproteins (LDLs) and lipid and clinical parameters in 104 asymptomatic dyslipidemic men and to identify biochemical and genetic factors that could contribute to the charge variability of LDL. LDL charge heterogeneity was evaluated by relative electrophoretic mobility (REM) on preformed 0.5% agarose gels and by chromatographic quantification of a minor electronegative LDL subfraction designated LDL(−). The mean REM value for LDL was 0.147±0.016 and the mean LDL(−) subfraction percentage was 5.6±2.8%. Both were positively correlated with common atherosclerotic risk factors, especially total cholesterol [for REM,r=0.27,P<0.005; for LDL(−),r=0.28,P=0.008] and LDL cholesterol [for REM,r=0.27,P=0.007; for LDL(−),r=0.26,P=0.01)] levels, and REM was positively correlated with triglycerides (r=0.27,P<0.005) and negatively with apoAI levels (r=−0.30,P<0.002). The variations in LDL charge were not due to oxidation, as measured by the lag phase and binding to the LDL receptor. The results of the 2 methods used to measure LDL charge were significantly correlated and had some identical characteristics (eg, association with LDL apoCIII content and plasma triglyceride levels in borderline and IIb dyslipidemic subjects); these methods reflect different specific features of LDL charge. The percentage of LDL(−) was correlated positively with the LDL sialic acid content (P<0.0001), whereas the REM was related to at least 2 distinct chromosomal loci. Multiple logistic analysis showed that individuals carrying minor alleles ofBsrDI (P<0.05), apoCIII/SacI (P<0.01), as well as the frequent allele ofXbaI (P<0.05) at the apoB and CIII gene loci had high REMs. This result suggests that LDL charge heterogeneity, which is positively correlated with the atherogenic lipid profile, is influenced by both genetic and biochemical factors.
Dietary Monounsaturated Fatty Acids Promote Aortic Atherosclerosis in LDL Receptor–Null, Human ApoB100–Overexpressing Transgenic Mice
Authors: Rudel Lawrence L. , Kelley Kathryn , Sawyer Janet K. , Shah Ramesh , Wilson Martha D.
Published: June 2011

Abstract
—In mice with genetically engineered high levels of plasma low density lipoprotein (LDL), we tested the hypothesis that an increase in the dietary content of monounsaturated fatty acids but not of polyunsaturated fatty acids would promote atherosclerosis. The mouse model used was an LDL receptor–null, human apoB100–overexpressing strain. Six experimental groups of 19 to 38 mice of both sexes were established when the animals had reached 8 weeks of age. For the next 16 weeks, individual groups were fed either a commercial diet or prepared diets including fat as 10% of energy, with 5 different fatty acid enrichment patterns including the following: saturated (sat),
cis
and
trans
monounsaturated (mono), and n-3 and n-6 polyunsaturated (poly). Highly significant differences (ANOVA,
P
<0.0001) in LDL cholesterol (in mg/dL) were found, with the rank order at 16 weeks being
trans
mono (mean, 1390)>sat (922) =
cis
mono (869)=n-6 poly (868)>n-3 poly (652)>commercial diet (526). Significant elevations in very low density lipoprotein cholesterol were also found in the
trans
and
cis
mono and sat groups, and triacylglycerol concentrations were also elevated in all groups. High density lipoprotein cholesterol concentrations were consistently low (20 to 50 mg/dL) in all groups. Highly significant differences (ANOVA,
P
<0.0001) in atherosclerosis, quantified by measurement of aortic cholesteryl ester concentration (mg/g protein) among dietary fatty acid groups were found, with the order being
trans
mono (mean, 50.4)>sat (35.6)=
cis
mono (34.6)>n-6 poly (18.3)=n-3 poly (9.7)=commercial diet (7.8). Therefore, in this mouse model of hypercholesterolemia, dietary
cis
or
trans
monounsaturated fat did not protect against atherosclerosis development, whereas aortic atherosclerosis in either of the polyunsaturated fat groups was significantly less than in the saturated fat group.
Inhibition of Tumor Necrosis Factor-α– and Interleukin-1–Induced Endothelial E-Selectin Expression by Thiol-Modifying Agents
Authors: Friedrichs Bärbel , Müller Cordula , Brigelius-Flohé Regina
Published: June 2011

Abstract—The expression of endothelial-leukocyte adhesion molecules has been postulated to be regulated by redox-sensitive events. Tumor necrosis factor-α (TNF-α)– and interleukin-1 (IL-1)–induced E-selectin expression was analyzed after pretreating human umbilical vein endothelial cells with different thiol-modifying agents, ie, diamide, phenylarsine oxide,N-ethylmaleimide, and diethyl maleate. E-selectin protein expression was quantified by indirect immunofluorescence. All compounds suppressed the cytokine-induced E-selectin expression in a concentration-dependent manner, whereas the antioxidantN-acetylcysteine showed no effect. The inhibitory effect of diamide (100 μmol/L, 1 hour) was reversible within 6 hours when the cells were allowed to recover before application of cytokines. Reversibility was strongly delayed when cells were deprived of glutathione by buthionine sulfoximine pretreatment. Glutathione depletion alone did not influence cytokine-induced E-selectin expression. Analysis of cellular glutathione status showed a 3-fold increase in oxidized glutathione after diamide treatment. Monochlorobimane labeling also revealed a decrease in total cellular thiols. During recovery, the glutathione status was restored within 1 hour, whereas total thiol content and E-selectin expression needed at least 6 hours to return to baseline. Complete inhibition of E-selectin expression by the vicinal thiol blocker phenylarsine oxide (0.5 μmol/L) was reversed by dithiols like dithiothreitol or dimercaptopropanol, but not by the monothiol 2-mercaptoethanol. These data suggest that proteins with essential thiols, most probably vicinal thiols. are involved in the IL-1– and TNF-α–mediated induction of E-selectin. These thiols must be in the reduced state; oxidation or other modification thereof attenuates or abolishes the cells’ response to the cytokines.
Adsorption of Fibrinogen to Droplets of Liquid Hydrophobic Phases
Authors: Retzinger Gregory S. , DeAnglis Ashley P. , Patuto Samantha J.
Published: June 2011

Abstract—Fibrinogen adsorbs spontaneously from aqueous media containing that protein to droplets of liquid hydrophobic phases dispersed in those same media. Examples of such phases include mineral oils, straight-chain hydrocarbons, and various plant- and animal-derived oils. Lecithin preexisting on the surface of oil droplets reduces significantly the amount of fibrinogen that can otherwise bind to them. When bound, fibrinogen remains active in the classic sense of fibrin gelation. As a consequence, oil droplets coated with fibrinogen can participate in a host of biologically important adhesive processes in which the protein would be expected to participate. Certain polyanions, eg, heparin, pentosan polysulfate, dextran sulfate, and suramin, bind to adsorbed fibrin(ogen) and prevent thrombin-dependent adhesion of fibrinogen-coated surfaces. Thus, these polyanions can be used to prevent adhesion between fibrin(ogen)-coated oil droplets and other fibrin(ogen)-coated surfaces. Potential practical applications and biological implications of these phenomena are presented and discussed.
Fibronectin and Collagen I Matrixes Promote Calcification of Vascular Cells in Vitro, Whereas Collagen IV Matrix Is Inhibitory
Authors: Watson Karol E. , Parhami Farhad , Shin Victoria , Demer Linda L.
Published: June 2011

Abstract—Vascular calcification is a frequent component of atherosclerosis, yet the pathological mechanisms that regulate its formation are poorly understood. Calcification of the vessel wall may represent a process by which cells that normally exhibit a smooth muscle phenotype differentiate into cells that exhibit an osteoblast-like phenotype. One of the determinants of cellular phenotype is extracellular matrix; thus, we undertook the current study to evaluate the influence of extracellular matrix on calcification of vascular cells in vitro. Cell lines derived from bovine aortic media were divided into 1 of 3 groups: those that did not mineralize, those that mineralized slowly, or those that mineralized rapidly. When slowly mineralizing cells were plated onto matrix produced by rapidly mineralizing cells, the time required for mineralization decreased from 33±3.0 days to 7.8±1.3 days. Matrix produced by rapidly mineralizing cells was found to contain 3 times the amount of collagen I and fibronectin but 70% less collagen IV than nonmineralizing clones. When slowly mineralizing cells were cultured on purified collagen I or fibronectin, mineralized nodule formation, calcium incorporation, von Kossa staining, and alkaline phosphatase activity increased. In contrast, culturing slowly mineralizing cells on purified collagen IV inhibited these mineralization parameters. Furthermore, blocking antibodies to α5 integrins significantly inhibited the fibronectin-mediated increases in alkaline phosphatase activity, indicating that integrin-based signaling may be involved. These data suggest that matrix composition can regulate development of arterial calcification and that a subpopulation of vascular cells preferentially produces positively regulating matrix components.
Expression of Extracellular SOD and iNOS in Macrophages and Smooth Muscle Cells in Human and Rabbit Atherosclerotic Lesions
Authors: Luoma Jukka S. , Strålin Pontus , Marklund Stefan L. , Hiltunen Timo P. , Särkioja Terttu , Ylä-Herttuala Seppo
Published: June 2011

Abstract
—Oxidative processes play an important role in atherogenesis. Because superoxide anion and nitric oxide (NO) are important mediators in vascular pathology, we studied the expression of extracellular superoxide dismutase (EC-SOD) and inducible nitric oxide synthase (iNOS) in human and rabbit atherosclerotic lesions by using simultaneous in situ hybridization and immunocytochemistry and EC-SOD enzyme activity measurements. We also analyzed the presence in the arterial wall of oxidized lipoproteins and peroxynitrite-modified proteins as indicators of oxidative damage and possible mediators in vascular pathology. EC-SOD and iNOS mRNA and protein were expressed in smooth muscle cells and macrophages in early and advanced lesions. The expression of both enzymes was especially prominent in macrophages. As measured by enzyme activity, EC-SOD was the major SOD isoenzyme in the arterial wall. EC-SOD activity was higher in highly cellular rabbit lesions but lower in advanced, connective tissue–rich human lesions. Despite the abundant expression of EC-SOD, malondialdehyde-lysine and hydroxynonenal-lysine epitopes characteristic of oxidized lipoproteins and nitrotyrosine residues characteristic of peroxynitrite-modified proteins were detected in iNOS-positive, macrophage-rich lesions, thus implying that malondialdehyde, hydroxynonenal, and peroxynitrite are important mediators of oxidative damage. We conclude that EC-SOD, iNOS, and the balance between NO and superoxide anion play important roles in atherogenesis. EC-SOD and iNOS are highly expressed in lesion macrophages. High EC-SOD expression in the arterial wall may be required not only to prevent deleterious effects of superoxide anion but also to preserve NO activity and prevent peroxynitrite formation. Modulation of arterial EC-SOD and iNOS activities could provide means to protect arteries against atherosclerotic vascular disease.
LDL Oxidation and Extent of Coronary Atherosclerosis
Authors: van de Vijver Lucy P. L. , Kardinaal Alwine F. M. , van Duyvenvoorde Wim , Kruijssen Dick A. C. M. , Grobbee Diederick E. , van Poppel Geert , Princen Hans M. G.
Published: June 2011

Abstract—
Accumulated evidence indicates that oxidative modification of LDL plays an important role in the atherogenic process. Therefore, we investigated the relation between coronary atherosclerosis and susceptibility of LDL to oxidation in a case-control study in men between 45 and 80 years of age. Case subjects and hospital control subjects were selected from subjects undergoing a first coronary angiography. Subjects with severe coronary stenosis (≥85% stenosis in one and ≥50% stenosis in a second major coronary vessel) were classified as case subjects (n=91). Hospital control subjects with no or minor stenosis (≤50% stenosis in no more than two of the three major coronary vessels, n=94) and population control subjects free of plaques in the carotid artery (n=85) were pooled for the statistical analysis into one control category. Enrollment procedures allowed for similar distributions in age and smoking habits. Case subjects had higher levels of total and LDL cholesterol and triglycerides and lower levels of HDL cholesterol. Resistance time, maximum rate of oxidation, and maximum diene production were measured ex vivo using copper-induced LDL oxidation. A borderline significant inverse trend was observed for coronary atherosclerosis risk at increasing resistance time. Odds ratios (95% confidence interval) for the successive quartiles were 1.0 (reference), 0.77 (0.39 to 1.53), 0.67 (0.33 to 1.34), and 0.55 (0.27 to 1.15) (p
trend
=0.07). No relation with maximum rate of oxidation was found, and higher maximum diene levels were found in control subjects (
P
<.01). The main determinant of oxidation was the fatty acid composition of LDL. No effect of smoking or use of medication was observed. We conclude that although LDL resistance to oxidation may be a factor in atherogenesis, the ex vivo measure is not a strong predictor of severity of coronary atherosclerosis.
RXR Agonists Activate PPARα-Inducible Genes, Lower Triglycerides, and Raise HDL Levels In Vivo
Authors: Mukherjee Ranjan , Strasser Josef , Jow Lily , Hoener Patricia , Paterniti James R. , Heyman Richard A.
Published: June 2011

Abstract
—Peroxisome proliferator–activated receptors (PPARs) and retinoid X receptors (RXRs) are members of the intracellular receptor superfamily. PPARs bind to peroxisome proliferator–response elements (PPREs) as heterodimers with RXR and as such activate gene transcription in response to activators. Fibrates like gemfibrozil are well-known PPARα activators and are used in the treatment of hyperlipidemia. We show that the RXR ligand LGD1069 (Targretin
™
), like gemfibrozil, can activate the PPARα/RXR signal-transduction pathway, including transactivation of the bifunctional enzyme or acyl-CoA oxidase response elements in a cotransfection assay. The activation also occurs in vivo, whereby in rats treated with LGD1069 or gemfibrozil, bifunctional enzyme and acyl-CoA oxidase RNA are induced and the combination of LGD1069 and gemfibrozil leads to a greater induction. Importantly, in hypertriglyceridemic
db/db
mice treated with RXR or PPARα agonists, triglyceride levels are lowered, and the combination again has significantly greater efficacy. RXR agonists also raise HDL cholesterol levels without changing apoA-I RNA expression. This observation suggests the use of RXR-selective agonists, “rexinoids,” either alone or in combination with a fibrate as a new therapeutic approach to treating patients with high triglyceride and low HDL cholesterol levels.
Serum Total IGF-I, Free IGF-I, and IGFBP-1 Levels in an Elderly Population
Authors: Janssen J. A. M. J. L. , Stolk R. P. , Pols H. A. P. , Grobbee D. E. , Lamberts S. W. J.
Published: June 2011

Abstract
—Recently, a method to measure free insulin-like growth factor-I (IGF-I) levels has been developed. Free IGF-I levels may have greater physiological and clinical relevance than total (bound and free) IGF-I. The associations between the circulating IGF-I/IGF binding protein (IGFBP) system and cardiovascular disorders was studied. In a cross-sectional study of 218 healthy persons (103 men, 115 women) aged 55 to 80 years, fasting serum (total and free) IGF-I and IGFBP-1 levels, lipid profile, insulin, and glucose were measured. In addition, blood pressure, body mass index (BMI), and waist-hip ratio (WHR) were measured. Ultrasonography of both carotid arteries was performed to investigate the presence of atherosclerotic lesions. A history of angina pectoris, the presence of a possible or definite myocardial infarction on the ECG, and plaques in the carotid arteries were used as indicators of presence of cardiovascular signs and symptoms. Free IGF-I was inversely related to serum triglycerides (
P
=.04, adjusted for age and sex). Mean free IGF-I levels in subjects without signs or symptoms of cardiovascular diseases were significantly higher than in those with at least one cardiovascular symptom or sign (
P
=.002, adjusted for age and sex). Free IGF-I levels were also higher in subjects who had no atherosclerotic plaques in the carotid arteries (
P
=.02, adjusted for age and sex) and who had never smoked (
P
=.02, adjusted for age and sex). IGFBP-1 showed an inverse relation with insulin, BMI, and WHR and a positive relation with HDL cholesterol. The associations between IGFBP-1 levels and HDL cholesterol, WHR, and BMI remained significant after adjustment for fasting insulin levels. High fasting serum free IGF-I levels are associated with a decreased presence of atherosclerotic plaques and coronary artery disease and lower serum triglycerides, whereas high fasting IGFBP-1 levels are associated with a more favorable cardiovascular risk profile. The findings suggest that the IGF-I/IGFBP system is related to cardiovascular risk factors and atherosclerosis.
Phenotypic Variation in Heterozygous Familial Hypercholesterolemia
Authors: Pimstone Simon N. , Sun Xi-Ming , du Souich Christele , Frohlich Jiri J. , Hayden Michael R. , Soutar Anne K.
Published: June 2011

Abstract
—Familial hypercholesterolemia (FH) is caused by mutations in the LDL receptor (LDLR) gene and is usually associated with hypercholesterolemia, lipid deposition in tissues, and premature coronary artery disease (CAD). However, individuals with heterozygous FH in China exhibit a milder phenotype despite having deleterious mutations in the LDLR gene (X.-M. Sun et al,
Arterioscler Thromb
. 1994;14:85–94). Nineteen Chinese FH heterozygotes living in Canada were screened for the 11 mutations that had been described in FH patients living in China. One Chinese Canadian carried one of these mutations (Trp462Stop), 2 carried a previously unreported single-base substitution (Cys163Arg), and 1 carried a mutation observed in French-Canadian patients (Glu207Lys). Twelve additional carriers of these mutations were identified in the families of the index patients. Significantly higher LDL cholesterol concentrations were observed in FH heterozygotes with defined mutations living in Canada (mean±SD, 7.46±1.29, n=16) than in those living in China (4.35±1.09, n=18;
P
<.0001). Six of the 16 FH heterozygotes residing in Canada had evidence of tendon xanthomata and 4 had a history of premature CAD, whereas none of those in China had tendon xanthomata or CAD. Complete segregation between hypercholesterolemia and inheritance of a mutant allele was observed in 3 Canadian Chinese FH families. Thus, Chinese FH heterozygotes living in Canada exhibit a phenotype similar to that of other FH patients in Western societies. The difference between patients living in Canada and those living in China could be ascribed to differences in dietary fat consumption, showing that environmental factors such as diet play a significant role in modulating the phenotype of heterozygous FH.
von Willebrand Factor Does Not Influence Atherogenesis in Arteries Subjected to Altered Shear Stress
Authors: Nichols Timothy C. , Bellinger Dwight A. , Reddick Robert L. , Koch Gary G. , Sigman Jeff L. , Erickson Geoffrey , du Laney Tracey , Johnson Timothy , Read Marjorie S. , Griggs Thomas R.
Published: June 2011

Abstract
—The role of von Willebrand factor (vWF) in arterial neointimal formation that develops in arteries with altered shear stress was investigated using normal, heterozygous, and homozygous von Willebrand disease pigs (ie, vWD, or lacking vWF) that were fed normal pig chow. Shear stress was applied to carotid and femoral arteries with a Goldblatt clamp for 14 days, producing a ≥80% stenosis. Neointimal lesion size was measured by computer-assisted morphometry. Expression of proliferative cell nuclear antigen (PCNA) by neointimal and medial cells was used as a relative index of proliferative activity. For shear-stressed arteries, there was no significant difference in the number of smooth muscle cell layers in the lesion, lesion size, and percent of PCNA-positive neointimal or medial cells among normal, heterozygous, and homozygous vWD pigs (
P
≥.1, ANOVA). Lesions in pigs that expressed vWF (normals and heterozygotes) contained large amounts of vWF in the neointima, whereas lesions in vWD pigs had no detectable vWF. Moreover, no foam cells were detected in the lesions. Thus, the absence of vWF apparently does not alter the size of lesions in shear-stressed arteries in vWD pigs or the number of neointimal or medial cells expressing PCNA. Mechanism(s) involved with shear-induced modulation of smooth muscle cell proliferation, then, can operate independently of vWF in normolipemic pigs.
Sex and Topographic Differences in Associations Between Large-Artery Wall Thickness and Coronary Risk Profile in a French Working Cohort
Authors: Gariepy Jérôme , Salomon Jean , Denarié Nicolas , Laskri Fatiha , Mégnien Jean Louis , Levenson Jaime , Simon Alain
Published: June 2011

Abstract
—Previous reports have investigated associations between carotid intima-media thickness (IMT) and cardiovascular risk factors. Our objective was to investigate this question in greater depth by measuring both femoral and carotid IMT in relation to sex and multifactorial coronary risk. We investigated carotid and femoral artery IMT by using ultrasonography in 326 men and 462 women, 17 to 65 years old. We also evaluated body mass index, blood pressure, blood lipids, glucose, smoking, and Framingham coronary risk. In both vessels, IMT was lower in women than in men. Significant relations between carotid and femoral IMT existed with age and most risk factors in both sexes. After adjustment for age, carotid IMT was related to risk factors in both sexes except for diastolic blood pressure, HDL cholesterol, and smoking in women, whereas femoral IMT was related to triglycerides and smoking in both sexes, systolic blood pressure and blood glucose in men, and total and HDL cholesterol in women. Significant unadjusted and age-adjusted relations of Framingham risk existed with carotid and femoral IMT in both sexes, but slopes of these relations were greater (1) before than after age adjustment, (2) in men than in women at both sites, except the femoral artery after age adjustment, and (3) at the carotid than at the femoral site in both sexes before age adjustment. Carotid IMT in men appears to be a more powerful predictor than it is in women and femoral IMT in both sexes in reflecting multifactorial coronary risk burden, but these differences are partly conditional on age.
Age-Related Changes in Populations of Aortic Glycosaminoglycans
Authors: Tovar Ana M. F. , Cesar Davi C. F. , Leta Graziela C. , Mourão Paulo A. S.
Published: June 2011

Abstract
—Glycosaminoglycans were extracted from the intima and media layers of normal human thoracic aortas from donors of different ages. The arterial segments were devoid of macroscopically visible lesions obtained from patients who had no clinically evident cardiovascular disease. Total glycosaminoglycan content increases during the first 40 years of life. Changes in the content of hyaluronic acid and heparan sulfate are less noticeable. The content of chondroitin sulfate (mainly the 6-isomer) increases, whereas dermatan sulfate remains constant. Plasma LDL-affinity chromatography of dermatan sulfate+chondroitin 4/6-sulfate fractions allowed the separation of LDL high- and low-affinity glycosaminoglycan species. Remarkably, only glycosaminoglycan species with low affinity for plasma LDL increase with age in the disease-free areas of human thoracic aortas studied. These results suggest that age-related changes in glycosaminoglycan composition of the arterial wall do not contribute to increased deposition of plasma LDL. However, the alternative explanation that individuals with arterial glycosaminoglycans that avidly bind LDL would develop early and severe cardiovascular disease and would thus be excluded from our analysis cannot be ruled out.
Phenotype Interaction of
apobec-1
and
CETP
,
LDLR,
and
ApoE
Gene Expression in Mice
Authors: Nakamuta Makoto , Taniguchi Susumu , Ishida Brian Y. , Kobayashi Kunihisa , Chan Lawrence
Published: June 2011

Abstract
—Apolipoprotein (apo) B mRNA editing determines the amount of apoB-100 and apoB-48 produced. Surprisingly,
apobec-1
knockout mice, which do not edit apoB, have an essentially normal lipoprotein phenotype. By selected cross-breeding of mice of different genotypes, we show in this report that inactivation of editing produces profound phenotypic effects in
cholesteryl ester transfer protein (CETP)
transgenic mice and in
apoE
and
low density lipoprotein receptor (LDLR)
knockout mice. Compared with mice with an
apobec-1
+/+
background,
CETP
expression in
apobec-1
−/−
mice caused a doubling of the plasma apoB-100 concentration (from 3.5±0.6 to 8.8±1.9 mg/dL,
P
<.01) and a much greater shift of plasma cholesterol from HDL to IDL/LDL as assayed by fast protein liquid chromatography analysis; the ratio of non-HDL to HDL cholesterol was 0.47, 0.46, 0.76, and 1.43 in
apobec-1
+/+
/CETP

−/−

, apobec-1

−/−

/CETP

−/−

, apobec-1

+/+

/CETP

+/−

, and
apobec-1
−/−
/CETP

+/−

animals, respectively. Feeding of a Western-type diet further exaggerated the shift in this ratio. In
LDLR
−/−
mice, inactivation of
apobec-1
caused an ≈200% rise in plasma apoB-100 concentration, an ≈60% increase in apoE concentration, and a 70% increase in total plasma cholesterol, which resulted exclusively from an increase in non-HDL cholesterol. The exaggerated hypercholesterolemia involving the VLDL+LDL fractions was further enhanced by a Western-type diet. In contrast, in
apoE
−/−
mice, inactivation of
apobec-1
caused a massive increase (from <0.5 to 55.5±16.4 mg/dL) in plasma apoB-100 concentration but an ≈55% reduction in hypercholesterolemia due to partial amelioration of the marked VLDL+IDL elevation. However, the difference in lipid profiles between
apobec-1
+/+
/apoE

−/−

and
apobec-1
−/−
/apoE

−/−

mice was abolished in a time-dependent manner as further increases in total plasma cholesterol were induced by a Western-type diet. Whereas
apobec-1
inactivation in wild-type mice produced little or no change in lipoprotein phenotype, giving rise to speculation that apoB mRNA editing does not have significant effect on lipoprotein dynamics, we show herein that there is important gene-gene interaction between
apobec-1
and the
CETP, LDLR,
and
apoE
loci, which is subject to further substantial modulation by environmental factors such as a Western-type diet in mice.
Metalloproteinase Blockade by Local Overexpression of TIMP-1 Increases Elastin Accumulation in Rat Carotid Artery Intima
Authors: Forough Reza , Lea Holly , Starcher Barry , Allaire Eric , Clowes Monika , Hasenstab David , Clowes Alexander W.
Published: June 2011

Abstract
—We have recently demonstrated that the blockade of matrix metalloproteinases by local overexpression of the intrinsic inhibitor tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) reduces intimal hyperplasia. We now report a major change in the elastin content of the intima of rat carotid arteries seeded with TIMP-1–overexpressing smooth muscle cells. To understand the mechanism responsible for elastin accumulation, synthesis and degradation of elastin in TIMP-1 and control cell–seeded rats were measured. There were no differences in elastin mRNA or elastin synthesis, as documented by
14
[C]proline incorporation between TIMP-1 and control cell–seeded arteries. In contrast, there was an increase in cross-linked elastin in the TIMP-1 group. In addition, in TIMP-1 and control rats, an elastase activity of approximately 28 kD was detected by elastin zymography and was decreased in TIMP-1 cell–seeded vessels. The 28 kD elastolytic activity was inhibited by exogenously added TIMP-1 and EDTA but not by PMSF, suggesting that it was a metalloelastase. Therefore, we have demonstrated that a shift of the proteolytic balance toward protease inhibition by TIMP-1 overexpression does not change elastin synthesis but rather changes posttranslational processing, resulting in increased elastin accumulation.
Sialic Acid Content of LDL in Coronary Artery Disease: No Evidence of Desialylation in Subjects With Coronary Stenosis and Increased Levels in Subjects With Extensive Atherosclerosis and Acute Myocardial Infarction
Authors: Chappey B. , Beyssen B. , Foos E. , Ledru F. , Guermonprez J. L. , Gaux J. C. , Myara I.
Published: June 2011

Abstract
—We recently showed that sialic acid content of LDL was not a marker of early cardiovascular disease (
Arterioscler Thromb Vasc Biol
. 1995;15:334–339). Here, we investigated this parameter in patients with advanced coronary artery disease (CAD). We first examined 100 patients having undergone coronary angiography. The distribution of LDL sialic acid values was very similar in subjects with no coronary stenosis (31.3±3.7 nmol/mg LDL protein, mean±SD) and those with ≥75% stenosis in at least one main coronary artery or ≥50% stenosis in at least two main coronary arteries (32.1±5.5 nmol/mg LDL protein). In contrast, LDL sialic acid content was significantly increased in patients with both coronary stenosis and peripheral arterial atherosclerotic lesions compared with those with either no lesion or only one or the other type of lesion. We then examined LDL sialic acid content in 20 patients with acute myocardial infarction. LDL sialic acid content was significantly higher (35.9±3.2 nmol/mg LDL protein) than that in the CAD(−) control group. These data suggest that LDL sialic acid content increases with the extension of atherosclerosis and its progression to acute complications. To explain the discordance with Orekhov and coworkers (
Atherosclerosis
. 1991;86:153–161), who showed that LDL sialic acid content in patients with advanced CAD was lower than that in healthy subjects, we studied the time courses of sialic acid, TBARS, and vitamin E levels in LDL dialyzed in different experimental conditions. A continuous decrease in both sialic acid and vitamin E levels and an increase in TBARS levels were observed in LDL samples containing less than 1 mmol/L EDTA, the intensity and rapidity of which varied with the EDTA concentration in the buffer. Our data support the idea that desialylation may result from in vitro peroxidation of LDL.
Cyclic Stretch Upregulates Production of Interleukin-8 and Monocyte Chemotactic and Activating Factor/Monocyte Chemoattractant Protein-1 in Human Endothelial Cells
Authors: Okada Masaharu , Matsumori Akira , Ono Koh , Furukawa Yutaka , Shioi Tetsuo , Iwasaki Atsushi , Matsushima Kouji , Sasayama Shigetake
Published: June 2011

Abstract
—In vivo, vascular walls are exposed to mechanical stretch, which may promote atherogenesis. This study was designed to investigate the effect of mechanical stretch on the production and gene expression of cytokines in endothelial cells (ECs) of human umbilical veins. ECs were cultured on flexible silicone membranes and exposed to cyclic mechanical stretch. Although the secretion levels of interleukin (IL)-1β, tumor necrosis factor-α, IL-6, granulocyte (G) -colony stimulating factor(CSF), G and macrophage (M) -CSF, and M-CSF were not affected by cyclic stretch over 24 hours, the levels of IL-8 and monocyte chemotactic and activating factor (MCAF)/monocyte chemoattractant protein-1 (MCP-1) were significantly increased by cyclic stretch. Northern blot analysis indicated that the mRNA levels of IL-8 and MCAF/MCP-1 were upregulated by cyclic stretch as a function of its intensity. Cytochalasin D, which disrupts the actin cytoskeleton, abolished the stretch-induced gene expression of IL-8 and MCAF/MCP-1. In contrast, neither inhibition of stretch-activated ion channels nor disruption of microtubules affected the induction of these chemokines by cyclic stretch. Northern blot analysis using enzyme inhibitors showed that phospholipase C, protein kinase C, and tyrosine kinase were involved in the stretch-induced gene expression of IL-8 and MCAF/MCP-1, whereas cAMP- or cGMP-dependent protein kinase was not. In conclusion, cyclic stretch enhanced the secretion and gene expression of IL-8 and MCAF/MCP-1 in a stretch-dependent fashion, and the integrity of the actin cytoskeleton and activities of phospholipase C, protein kinase C, and tyrosine kinase may be essential in the process of stretch-induced gene induction of IL-8 and MCAF/MCP-1.