bluuebunny/crossref_metadata_2025 huggingface dataset:
LDL Hypercholesterolemia Is Associated With Accumulation of Oxidized LDL, Atherosclerotic Plaque Growth, and Compensatory Vessel Enlargement in Coronary Arteries of Miniature Pigs
Authors: Holvoet Paul , Theilmeier Gregor , Shivalkar Bharati , Flameng Willem , Collen Désiré
Published: June 2011

Abstract—The association between accumulation of oxidized low density lipoprotein (LDL) and (1) progression of atherosclerotic plaques and (2) compensatory enlargement was assessed in the coronary arteries of LDL-hypercholesterolemic miniature pigs. In miniature pigs fed a 4% cholesterol diet, LDL cholesterol levels increased from 27±3.5 mg/dL (mean±SEM, n=36) to 250±28 mg/dL (n=10), 260±15 mg/dL (n=6), and 260±17 mg/dL (n=10) at 6, 14, and 24 weeks, respectively. Mean intimal areas of lesions in the left anterior descending coronary artery of hypercholesterolemic pigs were 0.16±0.046 mm2at 6 weeks (n=10) and increased 5.4-fold (n=6,P<.05) and 10.6-fold (n=10,P<.001) at 14 and 24 weeks, respectively. Plaque growth was associated with an increase in mean internal elastic lamina area, from 1.44±0.17 to 4.38±0.52 mm2(P=.007) and in mean luminal area from 1.42±0.15 mm2in control pigs to 4.38±0.52 mm2in pigs fed a cholesterol diet for 24 weeks (P=.007 vs control). Levels of total LDL in the intima, measured immunocytochemically, were 0.031±0.0098, 0.11±0.057 (P≤.05), and 0.43±0.082 U (P<.001) at 6, 14, and 24 weeks, respectively. Corresponding levels of oxidized LDL were 0.034±0.023, 0.11±0.050 (P<.05), and 0.44±0.065 U (P<.001), respectively, suggesting that virtually all LDL in the intima is oxidized. Levels of oxidized LDL in the lesions were correlated with the intimal areas (r=.85,P<.0001) but were independent of plasma levels of LDL cholesterol and of oxidized LDL. Plaque levels of oxidized LDL were also correlated with internal elastic lamina areas (r=.72,P<.0001) and with luminal areas (r=.50,P=.0098). Plaque growth in the coronary arteries of LDL-hypercholesterolemic miniature pigs is associated with (1) an increase in plaque levels of oxidized LDL at constant plasma levels of LDL cholesterol and of oxidized LDL and (2) compensatory vessel enlargement proportional to plaque levels of oxidized LDL.
Extracellular Matrix Modulates Macrophage Functions Characteristic to Atheroma
Authors: Wesley Robert B. , Meng Xiaoping , Godin Denis , Galis Zorina S.
Published: June 2011

Abstract—Activated resident macrophages sustain atheroma, and a high macrophage content is associated with plaque vulnerability. Factors leading to differentiation and activation of these blood-derived cells remain largely uncharacterized. We investigated the contribution of interaction with collagen type I, the predominant component of atherosclerotic matrix, to differentiation and modulation of characteristic macrophage functions, including intracellular lipid accumulation and production of the typical matrix-degrading enzyme matrix metalloproteinase (MMP)-9. When used as an adhesion substrate for human peripheral blood monocytes in vitro, collagen type I increased monocyte differentiation, assessed by analysis of CD71 expression and cell spreading. Culturing on collagen type I doubled the number of differentiated monocytes at 24 hours (44.9±1.4% versus 18.4±1.7% on uncoated dishes,P<.001, n=3 independent experiments) and was a stronger stimulus for differentiation than phorbol myristate acetate, a known inducer of monocyte differentiation. The effect of substrate on intracellular accumulation of modified lipoproteins was assessed by quantitative confocal microscopy of monocytes incubated with fluorescent acetylated LDL. The collagen type I substrate also doubled the number of macrophages containing intracellular lipid and significantly increased the individual intracellular loading. Monocytes cultured on collagen type I also released more MMP-9 than did cells plated directly on plastic. The role of monocyte spreading was further assessed by treatment with colchicine, an inhibitor of cytoskeletal function, or with genistein, a nonspecific inhibitor of tyrosine kinases, shown to participate in cell adhesion. Cell spreading was inhibited in 72.3±6.7% of colchicine-treated and in 62.4±6.4% of genistein-treated monocytes (n=3,P<.01 in both cases). The same conditions also decreased secretion of MMP-9, and genistein reduced the number of acetylated LDL-containing cells (from 286±7 to 184±8 cells/mm2with genistein, n=3,P<.001). Data showed a strong correlation (r>.98) between monocyte spreading on collagen type I and intracellular lipid accumulation. Our results indicate that interaction with vascular matrix may play an important role in differentiation of peripheral blood monocytes into resident lipid-laden macrophages, which act as central stimulators throughout the natural history of atheroma.
Hyperinsulinemia and Cardiovascular Disease in Elderly Men
Authors: Burchfiel Cecil M. , Sharp Dan S. , Curb J. David , Rodriguez Beatriz L. , Abbott Robert D. , Arakaki Richard , Yano Katsuhiko
Published: June 2011

Abstract
—Hyperinsulinemia has been associated with cardiovascular disease (CVD), but whether this relation is independent of other CVD risk factors is uncertain. Most studies have focused on coronary heart disease (CHD), but few have included peripheral vascular disease (PVD) and stroke. Moreover, evidence in elderly and minority populations is limited. Between 1991 and 1993, 3562 elderly (71 to 93 years) Japanese-American men from the Honolulu Heart Program were examined and had fasting insulin levels measured. Hyperinsulinemia, defined as a fasting insulin ≥95th percentile among nonobese men with normal glucose tolerance and no diabetic history or medication use, was observed in 22% of the population. Subjects with hyperinsulinemia had a more adverse CVD risk factor profile and had higher age-adjusted prevalences of CHD, angina, PVD, thromboembolic stroke, and hemorrhagic stroke compared with those without hyperinsulinemia. Age-adjusted fasting insulin levels but not 2-hour levels were also significantly elevated (
P
<.01) in those with prevalent CVD compared with those without. In logistic regression analyses, adjustment for multiple CVD risk factors attenuated the relations of hyperinsulinemia with CHD, angina, and PVD to nonsignificant levels, whereas those involving thromboembolic and hemorrhagic stroke were strengthened and remained significant (odds ratios=2.27 and 7.53, 95% confidence intervals=1.25 to 4.13 and 1.65 to 34.25, respectively). When multivariate analyses were restricted to nondiabetic subjects, associations were slightly weaker and in general nonsignificant. Nondiabetic men with thromboembolic stroke were twice as likely to have hyperinsulinemia as those who were stroke-free, although this association was of borderline significance (odds ratio=1.99, 95% confidence interval=0.95 to 4.17,
P
=.069). In subjects with elevated total cholesterol levels, somewhat stronger associations were observed for PVD and stroke but not for CHD. Although further prospective studies are indicated, particularly for PVD and stroke, these cross-sectional results are consistent with an indirect role for insulin in CVD, wherein hyperinsulinemia or an underlying insulin-resistant state may adversely affect other CVD risk factors or serve as a marker for an atherogenic or thrombogenic state.
Influence of ApoE Content on Receptor Binding of Large, Buoyant LDL in Subjects With Different LDL Subclass Phenotypes
Authors: Barbagallo Carlo M. , Levine Gerri A. , Blanche Patricia J. , Ishida Brian Y. , Krauss Ronald M.
Published: June 2011

Abstract—We investigated the influence of apolipoprotein (apo) E–containing particles on LDL receptor binding of large, buoyant LDL subfractions (LDL I) from subjects with predominantly large (phenotype A) and small (phenotype B) LDL particles. Direct binding by human fibroblast LDL receptors was tested at 4°C before and after removal of apoE-containing particles by immunoaffinity chromatography. The binding affinity of total LDL I in phenotype B was greater than that in phenotype A (Kd of 1.83±0.3 and 3.43±0.9 nmol/L, respectively,P<.05). LDL I from phenotype B subjects had a higher apoE to apoB molar ratio than did that from phenotype A (0.16±0.04 versus 0.06±0.02,P<.05). Nondenaturing gradient gel electrophoresis of apoE-containing LDL I isolated by immunoaffinity chromatography revealed a substantially larger peak particle diameter than in apoE-free LDL I, and comparison of LDL I composition before and after immunoaffinity chromatography suggested an increase in triglyceride content of apoE-containing particles. After removal of these particles, there was a greater than twofold reduction in LDL receptor affinity of phenotype B LDL (Kd of 1.83±0.3 to 3.76±0.6,P<.01), whereas in phenotype A no change was observed (Kd of 3.43±0.9 to 3.57±0.4, respectively). The receptor affinity of apoE-free LDL I from phenotype A and B subjects did not differ. These findings confirm that large, buoyant LDL particles from phenotype B subjects have a higher LDL receptor affinity than does LDL I from phenotype A subjects and suggest that this difference is due to an increased content of large, triglyceride-enriched, apoE-containing lipoproteins. It is possible that the accumulation of these particles reflects abnormalities in the metabolism of remnant lipoproteins that contribute to atherosclerosis risk in phenotype B subjects.
Lipoprotein Lipase Gene Variation Is Associated With a Paternal History of Premature Coronary Artery Disease and Fasting and Postprandial Plasma Triglycerides
Authors: Humphries Steve E. , Nicaud Viviane , Margalef Joaquim , Tiret Laurence , Talmud Philippa J. , EARS for the
Published: June 2011

Abstract
—The
H
-allele of the intron 8
Hin
dIII polymorphism in the lipoprotein lipase (LPL) gene has been associated with a lower risk of myocardial infarction (MI) and plasma levels of triglycerides (TG). To test whether the
Hin
dIII site was in linkage disequilibrium with the functional variant LPL Serine447Stop (S447X), subjects from the European Atherosclerosis Research Study (EARS I) were genotyped for both polymorphic sites. This study included 515 offspring of fathers with a premature (<55 years old) MI, who were designated cases, and 930 age- and sex-matched control subjects from five different regions of Europe. Linkage disequilibrium between the two sites was very strong (>.99), with only three of the four possible haplotypes identified:
H
+S447,
H−
S447, and
H−
X447. The frequency of the
H−
X447 but not of the
H−
S447 haplotype was significantly lower in cases than in control subjects (.090 versus .117,
P
<.01) suggesting a protective effect for MI, with this difference being consistent in all five regions of Europe. Compared with individuals homozygous for the
H
+S447 haplotype, the odds ratio of having a paternal history of premature MI for
H−
X447 heterozygotes (≈20% of the population) was 0.71 (95% confidence interval, 0.55 to 0.92). In addition, there was an increase of the
H−
X447 haplotype frequency from north to south in control subjects (0.119 in Finland to 0.143 in the Mediterranean region,
P
<.01). Compared with the
H
+S447 haplotype, the
H−
X447 haplotype was associated with significantly lower concentrations of plasma TGs (5.4% lower,
P
=.01), with this effect being consistent over the regions of Europe. There was no significant evidence for a heterogeneity of effect between males and females or between cases and control subjects, although the effect on TG levels appeared to be the greatest in male cases (11% lower,
P
=.05). In a second study (EARS II), of 332 cases and 342 control subjects, postprandial clearance of TGs after a standard fat meal was examined. The
H−
X447 haplotype was associated with significantly lower postprandial triglyceride levels than was the
H
+S447 haplotype (9.4% smaller area under the curve,
P
<.05). Thus, the effects on MI risk and plasma lipids associated with the
H
allele appeared to be mainly mediated by the X447 mutation, and although the lowering effects associated with the
H−
X447 haplotype on fasting and postprandial TGs are not large, they are consistent with the lowering effect observed on MI risk throughout Europe.
Sterol 27-Hydroxylase– and ApoAI/Phospholipid–Mediated Efflux of Cholesterol From Cholesterol-Laden Macrophages
Authors: Westman Jan , Kallin Bengt , Björkhem Ingemar , Nilsson Jan , Diczfalusy Ulf
Published: June 2011

Abstract
—Cholesterol-laden, human monocyte–derived macrophages were found to contain 27-hydroxycholesterol in proportion to their content of cholesterol ester. In accordance with previous work with human lung alveolar macrophages, there was a significant efflux of 27-hydroxycholesterol and 3β-hydroxy-5-cholestenoic acid from the cultured cells. The efflux of 27-hydroxycholesterol was proportional to the cellular content of this steroid. Incubation of cholesterol-laden macrophages with reconstituted discoidal complexes made from apolipoprotein A-I and phospholipids resulted in a decrease in total cellular cholesterol, an increase in the efflux of free cholesterol, and a concomitant decrease in the total production and efflux of 27-oxygenated steroids, in particular, 3β-hydroxy-5-cholestenoic acid. Reconstituted discoidal complexes with the Milano variant of apolipoprotein A-I gave virtually identical results, whereas high density lipoprotein was less efficient. These results suggest that cultured cholesterol-laden cells can export some of their excess cholesterol in the form of 27-hydroxycholesterol, 3β-hydroxy-5-cholestenoic acid, and free cholesterol. In the presence of exogenous cholesterol acceptors, export of free cholesterol becomes more effective, resulting in less cholesterol exported via the 27-hydroxylase pathway. The balance between the two mechanisms for removal of cholesterol from macrophages may be of importance for formation of foam cells and development of atherosclerosis.
PAI-1 Plasma Levels in a General Population Without Clinical Evidence of Atherosclerosis
Authors: Margaglione Maurizio , Cappucci Giuseppe , d’Addedda Marina , Colaizzo Donatella , Giuliani Nicola , Vecchione Gennaro , Mascolo Giulio , Grandone Elvira , Di Minno Giovanni
Published: June 2011

Abstract
—Plasminogen activator inhibitor-1 (PAI-1) plasma levels have been consistently related to a polymorphism (4G/5G) of the PAI-1 gene. The renin-angiotensin pathway plays a role in the regulation of PAI-1 plasma levels. An insertion (
I
)/deletion (
D
) polymorphism of the angiotensin-converting enzyme (ACE) gene has been related to plasma and cellular ACE levels. In 1032 employees (446 men and 586 women; 22 to 66 years old) of a hospital in southern Italy, we investigated the association between PAI-1 4G/5G and the ACE
I/D
gene variants and plasma PAI-1 antigen levels. None of the individuals enrolled had clinical evidence of atherosclerosis. In univariate analysis, PAI-1 levels were significantly higher in men (
P
<.001), alcohol drinkers (
P
<.001), smokers (
P
=.009), and homozygotes for the PAI-1 gene deletion allele (4G/4G) (
P
=.012). Multivariate analysis documented the independent effect on PAI-1 plasma levels of body mass index (
P
<.001), triglycerides (
P
<.001), sex (
P
<.001), PAI-1 4G/5G polymorphism (
P
=.019), smoking habit (
P
=.041), and ACE
I/D
genotype (
P
=.042). Thus, in addition to the markers of insulin resistance and smoking habit, gene variants of PAI-1 and ACE account for a significant portion of the between-individual variability of circulating PAI-1 antigen concentrations in a general population without clinical evidence of atherosclerosis.
Genetic Analysis of the Difference in Diet-Induced Atherosclerosis Between the Inbred Mouse Strains SM/J and NZB/BlNJ
Authors: Pitman Wendy A. , Hunt Mark H. , McFarland Cynthia , Paigen Beverly
Published: June 2011

Abstract
—To identify the genetic factors affecting susceptibility to atherosclerosis, we studied the inheritance of plasma total cholesterol (TC) and HDL cholesterol (HDL-C) concentrations and susceptibility to atherosclerotic lesion formation in an (SM/J[SM]×NZB/BlNJ[NZB]) outcross, an (SM×NZB)F1[F1]×SM backcross, and the NXSM recombinant inbred (RI) strain set. After 18 or 26 weeks on the atherogenic diet, lesion sizes in female mice were 160±110 (SE) μm
2
for NZB, 100±60 for F1, and 3800±920 for SM. After 0, 4, or 26 weeks on the atherogenic diet, NZB had higher TC and HDL-C levels than either SM or F1. The F1 progeny had TC and HDL-C levels slightly higher than or similar to the SM/J parent, while lesion size in the F1 progeny was more similar to the NZB parent. Among the 15 RI strains, 8 resembled NZB and F1, 3 resembled SM, and 4 were intermediate between NZB and SM for lesion size. For the (SM×NZB)F1×SM backcross offspring, 26 resembled NZB and F1, 7 resembled SM, and 6 were intermediate between NZB and SM for lesion size. There was poor correlation between lesion size and plasma TC or HDL-C in the parental strains and the backcross. These data suggest that resistance to atherosclerosis is determined by at least one major dominant gene contributed by the NZB strain, which we have named
Ath8
.
Ath8
segregates independently of genes controlling TC and HDL-C levels.
Macrophage Phenotype in Mice Deficient in Both Macrophage-Colony–Stimulating Factor (Op) and Apolipoprotein E
Authors: de Villiers Willem J. S. , Smith Jonathan D. , Miyata Masaaki , Dansky Hayes M. , Darley Elizabeth , Gordon Siamon
Published: June 2011

Abstract—Mice deficient in both macrophage-colony–stimulating factor (M-CSF, op) and apolipoprotein E (apoE) have elevated cholesterol levels but are protected from atherosclerosis. To assess the contribution of macrophage (Mφ) phenotypic heterogeneity and scavenger receptor (SR-A) expression to this seeming paradox, we characterized the Mφ phenotype by immunohistochemistry in these animals. Lesion size was determined in animals fed a chow or Western-type diet, and lipoprotein clearance studies were performed in vivo. Op0/E0 mice have fourfold smaller aortic root lesions than op2/E0 animals despite 2.5-fold higher total plasma cholesterol levels. Mφs in atherosclerotic lesions of op2/E0 mice constitute a predominantly recruited and M-CSF–dependent population. In addition, Mφs in different locations in plaques show phenotypic heterogeneity. SR-A expression in op0/E0 mice is reduced in proportion to the decrease in Mφ numbers, and M-CSF is thus not an essential requirement for SR-A expression in vivo. M-CSF–deficient mice degrade injected AcLDL , showing an adequate level of SR-A activity present in vivo. In contrast, β-VLDL clearance in op0/E0 mice is decreased, implicating monocytes/Mφs in its catabolism. There is prominent lipid accumulation in op2/E0 Kupffer cells and hepatocytes but not in M-CSF–independent Kupffer Mφs from op0/E0 mice. SR-A, while abundantly expressed on both Kupffer cells and sinusoidal endothelial cells in op2/E0 mice, remains mainly on sinusoidal endothelial cells in op0/E0 mice. This may explain preservation of SR-A activity in these animals. Our findings clearly illustrate the importance of both M-CSF and M-CSF–dependent monocytes/Mφs in maintaining cholesterol homeostasis and in atherogenesis.
A Common Functional Polymorphism in the Promoter Region of the Microsomal Triglyceride Transfer Protein Gene Influences Plasma LDL Levels
Authors: Karpe Fredrik , Lundahl Björn , Ehrenborg Ewa , Eriksson Per , Hamsten Anders
Published: June 2011

Abstract
—Microsomal triglyceride transfer protein (MTP) is required for the assembly and cellular secretion of apolipoprotein B (apoB) –containing lipoproteins from the liver and intestine. The secretion pattern of apoB-containing lipoproteins is likely to influence the VLDL and LDL levels in plasma. By initial opportunistic screening for polymorphic sites in the regulatory region of the MTP gene by gene sequencing in 20 healthy male subjects, a common functional G/T polymorphism was detected 493 bp upstream from the transcriptional start point. There was differential binding of unique nuclear proteins at this site, as shown by electrophoretic mobility shift assay. The G variant seemed to bind two or three nuclear proteins that do not bind to the T variant. Expression studies with minimal promoter constructs linked to the chloramphenicol acetyltransferase reporter and transfected into HepG2 cells revealed marked enhancement of transcriptional activity with the T variant. The prevalence of the MTP promoter genotypes was investigated in a group of 184 healthy, middle-aged white men; the frequency of homozygosity for the MTP −493 T variant was .06 and the allele frequency of MTP −493T was .25 in the population. These homozygous subjects had a 22% lower LDL cholesterol concentration than did heterozygotes or subjects homozygous for the MTP −493 G variant (2.9±0.6 versus 3.7±0.8 mmol/L,
P
<.05). Analysis of apoB and triglyceride contents in VLDL subfractions revealed a markedly changed balance within the VLDL population. Subjects homozygous for the MTP −493 T variant had fewer but more lipid-rich VLDL particles, thereby arguing for an effect of MTP expression on the hepatic secretion of triglyceride-rich, apoB-containing lipoproteins. This common genetic variation of the MTP promoter is likely to have important implications for cardiovascular disease.
Association of Specific LDL Receptor Gene Mutations With Differential Plasma Lipoprotein Response to Simvastatin in Young French Canadians With Heterozygous Familial Hypercholesterolemia
Authors: Couture Patrick , Brun Louis D. , Szots François , Lelièvre Michel , Gaudet Daniel , Després Jean-Pierre , Simard Jacques , Lupien Paul J. , Gagné Claude
Published: June 2011

Abstract—In familial hypercholesterolemia (FH), the efficacy of the inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase shows considerable interindividual variation, and several genetic and environmental factors can contribute to explaining this variability. A randomized, double-blind, placebo-controlled clinical trial with simvastatin, an HMG-CoA reductase inhibitor, was conducted in 63 children and adolescents with heterozygous FH. The patients were grouped according to known LDL receptor genotype. After 6 weeks of treatment with 20 mg/d simvastatin, the mean reduction in plasma LDL cholesterol in patients with the W66G mutation (n=14) was 31%, whereas in the deletion>15 kb (n=23) and the C646Y mutation groups (n=10), it was 38% and 42%, respectively (P<0.05). After treatment with simvastatin, HDL cholesterol levels were increased in all groups, and triglyceride concentrations were significantly reduced. Multiple regression analyses suggested that 42% of the variation of the LDL cholesterol response to simvastatin can be attributed to variation in the mutant LDL receptor locus, apolipoprotein E genotype, and body mass index, while 35% of the variation in HDL cholesterol response was explained by sex and baseline HDL cholesterol. These results show that simvastatin was an effective and well-tolerated therapy for FH in the pediatric population for all LDL receptor gene mutations. Moreover, the nature of LDL receptor gene mutations and other genetic and constitutional factors play a significant role in predicting the efficacy of simvastatin in the treatment of FH in children and adolescents.
Effect of 17β-Estradiol on Inhibition of Platelet Aggregation In Vitro Is Mediated by an Increase in NO Synthesis
Authors: Nakano Yukiko , Oshima Tetsuya , Matsuura Hideo , Kajiyama Goro , Kambe Masayuki
Published: June 2011

Abstract
—The low prevalence of coronary heart disease in premenopausal women and its increase after menopause are well established. Although estrogen is thought to play a role in protecting the vasculature, the mechanism has not been fully clarified. The contribution of platelets to atherosclerotic cardiovascular diseases is well recognized. The present study focused on the still-controversial effect of estrogen on platelet function. We investigated the in vitro effects of estrogen on human platelets, including their aggregation, Ca
2+
metabolism, the synthesis of cyclic nucleotides, and NO (nitrite/nitrate) synthesis after stimulation with thrombin or ADP. Pretreatment of platelets with 17β-estradiol reduced the platelet aggregation induced by thrombin or ADP, whereas 17α-estradiol had no effect. 17β-Estradiol accelerated the recovery of [Ca
2+
]
i
after the agonist-induced peak and reduced the area under the curve of accumulated platelet [Ca
2+
]
i
but did not alter the baseline [Ca
2+
]
i
, Ca
2+
influx induced by thrombin or ADP, the release of Ca
2+
from internal stores, or the size of internal Ca
2+
stores. Pretreatment of platelets with 17β-estradiol had no effect on the intracellular concentration of cAMP but increased that of cGMP in agonist-stimulated platelets. Additionally, 17β-estradiol increased the platelet concentration of nitrite/nitrate in a dose-dependent manner. These effects of 17β-estradiol on platelet aggregation, Ca
2+
metabolism, and NO synthesis were abolished by exposure to
N
G
-monomethyl-
l
-arginine, an NO synthesis inhibitor. These results suggest that 17β-estradiol plays an important role in inhibiting platelet aggregation by promoting Ca
2+
extrusion or reuptake activity that is dependent on the production of cGMP by increasing NO synthesis.
Fibronectin Expression and Aortic Wall Elastic Modulus in Spontaneously Hypertensive Rats
Authors: Bézie Yvonnick , Lamazière Jean-Marie Daniel , Laurent Stéphane , Challande Pascal , Cunha Roberto Sa , Bonnet Jacques , Lacolley Patrick
Published: June 2011

Abstract
—Recent studies have shown that large-artery wall remodeling per se does not reduce distensibility in hypertension, indicating qualitative or quantitative changes in arterial components. The aim of the study was to determine in 1-year-old spontaneously hypertensive rats (SHRs) the changes in the elastic properties of large arteries, as assessed by the incremental elastic modulus (E
inc
), and the changes in the extracellular matrix, including fibronectin (FN) and α5β1-integrin. The relationship between E
inc
and circumferential wall stress was calculated from in vivo pulsatile changes in blood pressure and arterial diameter by using a high-resolution echo-tracking system at the site of the abdominal aorta and in vitro medial cross-sectional area. E
inc
-stress curves and FN and integrin α5-subunit contents were determined for each animal. Mean stress and E
inc
were higher in SHRs than in Wistar rats. However, in a common range of stress, E
inc
-stress curves for SHRs were superimposable on those for Wistar rats, indicating that wall materials in both strains have equivalent mechanical behavior. Immunohistochemistry indicated that total FN, EIIIA FN isoform, and α5-integrin increased in the SHRs aortas without changes in elastin and collagen densities. Total FN was also increased in SHRs as determined by Western blot analysis. No differences in FN and α5-subunit mRNAs were detected between SHRs and Wistar rats. These results indicate that the aortic wall material of SHRs and Wistar rats have equivalent mechanical properties, although in SHRs it is subjected to a higher level of stress. By increasing cell-matrix attachment sites, FN may participate in the mechanical adaptation of both cellular and matrix components in SHRs.
Photochemically Induced Endothelial Injury in the Mouse as a Screening Model for Inhibitors of Vascular Intimal Thickening
Authors: Kikuchi Shinji , Umemura Kazuo , Kondo Kazunao , Saniabadi Abby R. , Nakashima Mitsuyoshi
Published: June 2011

Abstract
—We have established a mouse model of intimal thickening and assessed its suitability for experimental studies of intimal thickening. Neointimal formation was observed after endothelial injury by photochemical reaction between transluminal green light and systemically administered rose Bengal, which represents a nonmechanical approach to vessel wall denudation. Intimal thickening began 7 days after endothelial injury, reached a maximum after 21 days, and then remained unchanged for as long as 42 days. Furthermore, as a consequence of neointimal proliferation, the luminal area gradually decreased. The cells in the neointimal layer were identified as smooth muscle cells by immunohistochemical staining with an α-actin–specific antibody. Extracellular matrix deposition in the neointima was markedly increased beyond 14 days after injury. Smooth muscle cell proliferation, as measured by pulse labeling of 5-bromo-2′-deoxyuridine, was identified initially in the media 2 days after vessel wall denudation, with the proliferative activity’s shifting almost exclusively to the neointima within 7 days. Endothelial regeneration, as indicated by Evans blue staining, was complete within 21 days after injury. To assess the suitability of this model for experimental studies on intimal thickening, the effect of tranilast, an antiallergy drug with a broad spectrum of pharmacological actions on intimal thickening, was investigated. Tranilast (100 mg · kg
−1
· d
−1
PO) significantly (
P
<0.05) reduced smooth muscle cell proliferation in the neointima and media 7 days after injury and neointimal formation 21 days after injury in treated mice compared with vehicle-treated mice. This simple experimental mouse model is suitable for studying factors promoting or inhibiting intimal thickening after endothelial injury and for developing therapeutic strategies against intimal thickening.
Apolipoprotein B and Coronary Artery Disease in Women
Authors: Westerveld H. Tineke , van Lennep Jeanine E. Roeters , van Lennep Henk W. O. Roeters , Liem An-Ho , de Boo Job A. J. , van der Schouw Yvonne T. , Erkelens D. Willem
Published: June 2011

Abstract
—The association between plasma apolipoprotein (apo) B concentrations and angiographically determined coronary artery disease (CAD) was investigated in women in a cross-sectional study. Stenosis of >60% in 1 or more coronary arteries was classified as CAD+. CAD− was defined as a maximum stenosis of 10% in any coronary artery. Fasting plasma concentrations of apoB, apoA-I, cholesterol (chol), low density lipoprotein cholesterol (LDL-chol), high density lipoprotein cholesterol (HDL-chol), and triglycerides (TGs) were determined. Information on nonlipid risk factors was obtained from questionnaires. CAD+ women (n=160) were older than CAD− women (n=129), 64.0±7.8 vs 57.8±11.1 years, respectively. CAD+ compared with CAD− women had higher frequencies of diabetes (14.7% vs 5.8%,
P
=0.05), hypertension (53% vs 37%,
P
=0.018), and ever-smoking (48% vs 35%,
P
<0.001). CAD+ women had higher plasma concentrations of apoB (1.48±0.32 vs 1.25±0.34 g/L,
P
<0.001), chol (7.01±1.19 vs 6.38±1.22 mmol/L,
P
=0.001), LDL-chol (4.74±1.09 vs 4.13±1.13 mmol/L,
P
<0.001), and TGs (1.98±0.84 vs 1.71±0.93 mmol/L,
P
=0.007) and lower levels of HDL-chol (1.28±0.28 vs 1.37±1.38 mmol/L,
P
=0.028). After correction for nonlipid risk factors, apoB, chol, LDL-chol, HDL-chol, and TG were independently related to CAD. In the lowest quartiles of chol, LDL-chol, and TG, CAD+ women had higher apoB concentrations than CAD− women. In contrast, chol, LDL-chol, TG, or HDL-chol levels were not different in any quartile of apoB. ApoB showed the most significant relation with the number of stenotic vessels, and apoB was associated with CAD in the normolipidemic subgroup. In conclusion, apoB was superior to chol, LDL-chol, HDL-chol, TG, and apoA-I in discriminating between CAD+ and CAD−.
Influence of Glycation on LDL-Induced Generation of Fibrinolytic Regulators in Vascular Endothelial Cells
Authors: Zhang Jianying , Ren Song , Sun Dongfeng , Shen Garry X.
Published: June 2011

Abstract—Hyperglycemia and dyslipidemia are two biochemical markers of diabetes mellitus. Increased incidence of cardiovascular disease and impaired fibrinolytic activity have been found in diabetic subjects. Previous studies have demonstrated that low density lipoproteins (LDLs) stimulate the production of plasminogen activator inhibitor-1 (PAI-1) and reduce the generation of tissue plasminogen activator (tPA) in vascular endothelial cells (ECs). The present study investigated the effect of glycated LDL on the production of PAI-1 and tPA in cultured human umbilical vein ECs (HUVECs). Glycation increased the abundance of glucitollysine and conjugated dienes in LDL and amplified the overproduction of PAI-1 and the reduction in tPA generation from HUVECs induced by LDL. The steady-state levels of PAI-1 mRNA in glycated LDL–treated ECs were significantly higher than those in native LDL–treated cells. Actinomycin D blocked the increase in PAI-1 generation induced by glycated LDL. Glycated LDL did not significantly reduce the levels of tPA mRNA but attenuated de novo synthesis of tPA in ECs. Treatment with 25 mmol/L aminoguanidine, an antioxidant and inhibitor of the formation of advanced glycation end products, during glycation normalized glycated LDL–induced generation of PAI-1 and tPA in ECs. The results of the present study indicate that glycation enhances the production of PAI-1 and attenuates tPA synthesis in ECs induced by LDL, which may contribute to the increased incidence of cardiovascular complications in diabetes. Formation of advanced glycation end products or peroxidation may be involved in glycated LDL–induced alterations in the generation of fibrinolytic regulators from ECs.
Apolipoprotein A-I
Zavalla
(Leu
159
→Pro)
Authors: Miller Michael , Aiello David , Pritchard Haydn , Friel Gina , Zeller Karen
Published: June 2011

Abstract
—We investigated the molecular defect causing high density lipoprotein cholesterol (HDL-C) deficiency in a male proband and his family members. Amplification and sequencing of genomic DNA disclosed a novel base-pair substitution at residue 159 in the apolipoprotein (apo) A-I gene. This substitution resulted in the loss of an
Avi
II restriction site and a predicted substitution of leucine with proline at residue 159. Restriction enzyme analysis demonstrated absence of the
Avi
II site in 19 of 40 biological family members. Compared with familial controls, subjects with the apoA-I
Zavalla
variant had reduced HDL-C (1.16 versus 0.27 mmol/L,
P
<0.0001), apoA-I (38.7 versus 124.4 mg/dL,
P
<0.0001), and apoA-II (14.3 versus 19.0 mg/dL,
P
<0.0001) levels. Two subjects who have developed coronary artery disease to date possess additional cardiovascular risk factors. Other heterozygotes for apoA-I
Zavalla
are presently without symptomatic coronary artery disease. This study identifies a monogenic cause of hypoalphalipoproteinemia, with the single base-pair substitution having a dominant effect on the low HDL-C phenotype. In addition, it extends recent observations that HDL-C deficiency states may be more prone to the development of premature coronary artery disease when accompanied by additional cardiovascular risk factors.
Lipoprotein(a) Level Does Not Predict Restenosis After Percutaneous Transluminal Coronary Angioplasty
Authors: Alaigh Poonam , Hoffman Carol J. , Korlipara Giridhar , Neuroth Arlene , Dervan John P. , Lawson William E. , Hultin Mae B.
Published: June 2011

Abstract
—The serum lipoprotein(a) [Lp(a)] level is a known risk factor for arteriosclerotic coronary artery disease. However, its association with restenosis after percutaneous transluminal coronary angioplasty (PTCA) is controversial. We hypothesized that the Lp(a) level is a significant risk factor for restenosis after angioplasty through a pathophysiological mechanism leading to excess thrombin generation or inhibition of fibrinolysis. We designed a prospective study of the relation of Lp(a) to outcome after PTCA, in which we measured selected laboratory variables at entry and collected clinical, procedural, lesion-related, and outcome data pertaining to restenosis. Restenosis was defined as >50% stenosis of the target lesion by angiography or as ischemia in the target vessel distribution by radionuclide-perfusion scan. Before the patients underwent PTCA, blood was obtained by venipuncture for measurement of Lp(a), total cholesterol, thrombin-antithrombin (TAT) complex, α
2
-antiplasmin–plasmin (APP) complex, and plasminogen activator inhibitor-1 (PAI-1). Evaluable outcome data were obtained on 162 subjects, who form the basis of this report. Restenosis occurred in 61 subjects (38%). The Lp(a) level was not correlated significantly with TAT, APP, PAI-1, or the TAT-APP ratio. Levels of TAT, APP, and PAI-1 were not statistically different in the patients with versus those without restenosis. The median ratio of TAT to APP was 2-fold higher in the restenosis group, and this difference approached statistical significance (
P
=0.07). Univariate analysis was performed for the association of clinical, lesion-related, and procedural risk factors with restenosis. Lp(a) levels did not differ significantly in the restenosis versus no-restenosis group, whether assessed categorically (>25 mg/dL versus <25 mg/dL) or as a continuous variable by Mann-Whitney
U
test. The number of lesions dilated and the lack of family history of premature heart disease were significantly associated with restenosis (
P
=0.002 and
P
=0.008, respectively). A history of diabetes mellitus was of borderline significance (
P
=0.055). By multiple logistic regression analysis, the number of lesions dilated was the only variable significantly associated with restenosis (
P
=0.03). We conclude that the number of lesions dilated during PTCA is a significant risk factor for restenosis, whereas the serum Lp(a) level was not a significant risk factor for restenosis in our patient population. The TAT to APP ratio merits further study as a possible risk factor for restenosis.
Atherogenic Properties of Enzymatically Degraded LDL
Authors: Klouche Mariam , Gottschling Sandra , Gerl Verena , Hell Wolfgang , Husmann Matthias , Dorweiler Bernhard , Messner Martina , Bhakdi Sucharit
Published: June 2011

Abstract—The mechanisms underlying the selective accumulation of macrophages in early atherosclerotic lesions are poorly understood but are likely to be related to specific properties of altered low density lipoprotein (LDL) deposited in the subendothelium. Enzymatic, nonoxidative degradation of LDL converts the lipoprotein to a potentially atherogenic moiety, enzymatically altered LDL (E-LDL), which activates complement and is rapidly taken up by human macrophages via a scavenger receptor–dependent pathway. Immunohistological evidence indicates that E-LDL is present in an extracellular location in the early lesion. We report that E-LDL causes massive release of monocyte chemotactic protein 1 (MCP-1) from macrophages and that expression of interleukin 8 or RANTES remains unchanged. Release of MCP-1 was preceded by a rapid expression of MCP-1 mRNA, which was detectable after 15 minutes, reached maximum levels after 1 hour, and remained detectable for 12 hours after exposure to concentrations as low as 10 μg/mL E-LDL. MCP-1 mRNA induction and protein release by E-LDL exceeded that evoked by oxidized LDL. Release of MCP-1 was dependent on de novo protein synthesis and on the activity of tyrosine kinases. At higher concentrations, E-LDL, but not oxidized LDL, exerted toxic effects on macrophages that in part appeared to be due to apoptosis. The results show that E-LDL possesses major properties of an atherogenic lipoprotein.
Chronic Blockade of NO Synthase Activity Induces a Proinflammatory Phenotype in the Arterial Wall
Authors: Luvarà Giuseppina , Pueyo Maria E. , Philippe Monique , Mandet Chantal , Savoie Françoise , Henrion Daniel , Michel Jean-Baptiste
Published: June 2011

Abstract—Chronic blockade of NO production induces hypertension and early occlusive and fibrotic end-stage organ damage owing to vascular lesions in the brain, kidney, and heart. In this study, we evaluated the inflammatory phenotypic changes induced in the arterial wall by chronicNG-nitro-l-arginine methyl ester (L-NAME) administration and the effect of an angiotensin II receptor (AT1) antagonist, irbesartan, on these changes. For this purpose, 2 groups of rats received L-NAME in the drinking water (50 mg · kg−1· d−1) for 2 months. One group received no other treatment and the other was treated with irbesartan (10 mg · kg−1· d−1). A third group (controls) received neither L-NAME nor irbesartan. After 8 weeks, plasma, aortas, and left ventricles were sampled from all 3 groups. Expression of inducible NO synthase (iNOS) was evaluated at both the mRNA (quantitative reverse transcription–polymerase chain reaction) and the protein (Western blot and immunohistochemistry) level in the aorta. Expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was evaluated by reverse transcription–polymerase chain reaction, Western immunoblotting, and immunohistochemistry; inflammatory cell infiltration by immunohistochemistry; and fibrosis by Sirius red staining. Chronic L-NAME administration induced the expression of iNOS in the aorta, which was localized in smooth muscle cells as shown by immunohistochemistry and NADPH diaphorase activity. ICAM-1 and VCAM-1 expression was also increased in aortas of L-NAME–treated rats. These phenotypic changes of the vascular wall were associated with inflammatory cell infiltration and fibrosis in the heart. All of these pathological phenomena were prevented by the angiotensin II antagonist irbesartan. The proinflammatory phenotypic changes of the vascular wall induced by blockade of NOS activity could be involved in the interaction between endothelial dysfunction and the development of arteriosclerosis.
Transcriptional Activation of Scavenger Receptor Expression in Human Smooth Muscle Cells Requires AP-1/c-Jun and C/EBPβ
Authors: Mietus-Snyder Michele , Glass Christopher K. , Pitas Robert E.
Published: June 2011

Abstract
—Reactive oxygen species generated by treatment of smooth muscle cells (SMCs) with either phorbol 12-myristate 13-acetate or with the combination of H
2
O
2
and vanadate strongly induce expression of the class A scavenger receptor (SR-A) gene. In the current studies,
cis-
acting elements in the proximal 245 bp of the SR-A promoter were shown to direct luciferase reporter expression in response to oxidative stress in both SMCs and macrophages. A composite activating protein-1 (AP-1)/ets binding element located between –67 and –50 bp relative to the transcriptional start site is critical for macrophage SR-A activity. Mutation of either the AP-1 or the ets component of this site also prevented promoter activity in SMCs. Mutation of a second site located between –44 and –21 bp, which we have identified as a CCAAT/enhancer binding protein (C/EBP) element, reduced the inducible activity of the promoter in SMCs by 50%, suggesting that combinatorial interactions between these sites are necessary for optimal gene induction. Interactions between SMC nuclear extracts and the SR-A promoter were analyzed by electrophoretic mobility shift assay. c-Jun/AP-1 binding activity, specific for the –67- to –50-bp site, was induced in SMCs by the same conditions that increased SR-A expression. Moreover, phorbol 12-myristate 13-acetate, H
2
O
2
, or the combination of H
2
O
2
and sodium orthovanadate (vanadate) activated c-Jun–activating kinase. The binding activity within SMC extracts specific for the C/EBP site was shown to be C/EBPβ in SMCs. Taken together, these findings demonstrate that reactive oxygen species regulate the interactions between c-Jun/AP-1 and C/EBPβ in the SR-A promoter. Furthermore, induction of oxidative stress in THP-1 cells, with a combination of 10 μmol/L vanadate and 100 μmol/L H
2
O
2
, induced macrophage differentiation, adhesion, and SR activity. These data suggest that vascular oxidative stress may contribute to the induction of SR-A expression and thereby promote the uptake of oxidatively modified low density lipoprotein by both macrophage and SMCs to produce foam cells in atherosclerotic lesions.
Factors Influencing the Ability of HDL to Inhibit Expression of Vascular Cell Adhesion Molecule-1 in Endothelial Cells
Authors: Ashby Dale T. , Rye Kerry-Anne , Clay Moira A. , Vadas Mathew A. , Gamble Jennifer R. , Barter Philip J.
Published: June 2011

Abstract—We have previously reported that high density lipoproteins (HDLs) inhibit the cytokine-induced expression of adhesion molecules in endothelial cells. Here we investigate whether different preparations of HDLs vary in their ability to inhibit the expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs) activated by tumor necrosis factor-α (TNF-α). HDLs collected from a number of different human subjects all inhibited VCAM-1 expression in a concentration-dependent manner, although the extent of inhibition varied widely between subjects. The inhibitory activities of the HDL2and HDL3subfractions isolated from individual subjects also differed. Whether equated for concentrations of apolipoprotein (apo) A-I or cholesterol, the inhibitory activity of HDL3was superior to that of HDL2. This difference remained apparent even when the HDL subfractions were present only during preincubations with the HUVECs and were removed before activation by TNF-α. To determine whether the inhibitory effect of HDL3was influenced by apolipoprotein composition, preparations of HDL3were modified by replacing all of their apo A-I with apo A-II. This change in apolipoprotein composition had no effect on the ability of the HDL3to inhibit endothelial VCAM-1 expression. Thus, it has been shown that different preparations of HDLs differ markedly in their abilities to inhibit VCAM-1 expression in cytokine-activated HUVECs. The mechanism underlying the differences remains to be determined.
Inhibition of NO Synthesis Induces Inflammatory Changes and Monocyte Chemoattractant Protein-1 Expression in Rat Hearts and Vessels
Authors: Tomita Hideharu , Egashira Kensuke , Kubo-Inoue Mayuko , Usui Makoto , Koyanagi Masamichi , Shimokawa Hiroaki , Takeya Motohiro , Yoshimura Teizo , Takeshita Akira
Published: June 2011

Abstract—We recently showed that chronic inhibition of NO synthesis byNω-nitro-l-arginine methyl ester (L-NAME) causes coronary vascular remodeling (ie, vascular fibrosis and medial thickening) in rats. To test the hypothesis that the inhibition of NO synthesis induces inflammatory changes in the heart, we characterized the inflammatory lesions that occurred during L-NAME administration and determined whether inflammation involved the induction of monocyte chemoattractant protein-1 (MCP-1) in vivo. During the first week of L-NAME administration to Wistar-Kyoto rats, we observed a marked infiltration of mononuclear leukocytes (ED1-positive macrophages) and fibroblast-like cells (α-smooth muscle actin–positive myofibroblasts) into the coronary vessels and myocardial interstitial areas. These inflammatory changes were associated with the expression of proliferating cell nuclear antigen and MCP-1 (both mRNA and protein). The areas affected by inflammatory changes, as well as the expression of MCP-1 mRNA, declined after longer (28 days) treatment with L-NAME and were replaced by vascular and myocardial remodeling. Our results support the hypothesis that the inhibition of NO synthesis induces inflammatory changes in coronary vascular and myocardial tissues and involves MCP-1 expression. Results also suggest that the early stages of inflammatory changes are important in the development of later-stage structural changes observed in rat hearts.