bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced Atherosclerotic Lesions in Mice Deficient for Total or Macrophage-Specific Expression of Scavenger Receptor-A
Authors: Babaev Vladimir R. , Gleaves Linda A. , Carter Kathy J. , Suzuki Hiroshi , Kodama Tatsuhiko , Fazio Sergio , Linton MacRae F.
Published: June 2011

Abstract
—The absence of the scavenger receptor A (SR-A)-I/II has produced variable effects on atherosclerosis in different murine models. Therefore, we examined whether SR-AI/II deficiency affected atherogenesis in C57BL/6 mice, an inbred strain known to be susceptible to diet-induced atherosclerotic lesion formation, and whether the deletion of macrophage SR-AI/II expression would modulate lesion growth in C57BL/6 mice and LDL receptor (LDLR)
−/−
mice. SR-AI/II–deficient (SR-AI/II
−/−
) female and male mice on the C57BL/6 background were challenged with a butterfat diet for 30 weeks. No differences were detected in plasma lipids between SR-AI/II
−/−
and SR-AI/II
+/+
mice, whereas both female and male SR-AI/II
−/−
mice had a tremendous reduction (81% to 86%) in lesion area of the proximal aorta compared with SR-AI/II
+/+
mice. Next, to analyze the effect of macrophage-specific SR-AI/II deficiency in atherogenesis, female C57BL/6 mice were lethally irradiated, transplanted with SR-AI/II
−/−
or SR-AI/II
+/+
fetal liver cells, and challenged with the butterfat diet for 16 weeks. In a separate experiment, male LDLR
−/−
mice were reconstituted with SR-AI/II
−/−
or SR-AI/II
+/+
fetal liver cells and challenged with a Western diet for 10 weeks. No significant differences in plasma lipids and lipoprotein profiles were noted between the control and experimental groups in either experiment. SR-AI/II
−/−
→C57BL/6 mice, however, had a 60% reduction in lesion area of the proximal aorta compared with SR-AI/II
+/+
→C57BL/6 mice. A similar level of reduction (60%) in lesion area was noted in the proximal aorta and the entire aorta en face of SR-AI/II
−/−
→LDLR
−/−
mice compared with SR-AI/II
+/+
→LDLR
−/−
mice. These results demonstrate in vivo that SR-AI/II expression has no impact on plasma lipid levels and that macrophage SR-AI/II contributes significantly to atherosclerotic lesion formation.
Effect of Human Scavenger Receptor Class A Overexpression in Bone Marrow–Derived Cells on Cholesterol Levels and Atherosclerosis in ApoE-Deficient Mice
Authors: Van Eck Miranda , De Winther Menno P. J. , Herijgers Nicole , Havekes Louis M. , Hofker Marten H. , Groot Pieter H. E. , Van Berkel Theo J. C.
Published: June 2011

Abstract
—In the arterial wall, scavenger receptor class A (SRA) is implicated in pathological lipid deposition. In contrast, in the liver, SRA is suggested to remove modified lipoproteins from the circulation, thereby protecting the body from their pathological action. The role of SRA on bone marrow–derived cells in lipid metabolism and atherogenesis was assessed in vivo by transplantation of bone marrow cells overexpressing human SRA (MSR1) to apoE-deficient mice. In vitro studies with peritoneal macrophages from the transplanted mice showed that macrophage scavenger receptor function, as measured by cell association and degradation studies with acetylated LDL, was ≈3-fold increased on overexpression of MSR1 in bone marrow–derived cells as compared with control mice. Despite the increased macrophage scavenger receptor function in vitro, no significant effect of MSR1 overexpression in bone marrow–derived cells on the in vivo atherosclerotic lesion development was found. In addition to arterial wall macrophages, liver sinusoidal Kupffer cells also overexpress MSR1 after bone marrow transplantation, which may scavenge atherogenic particles more efficiently from the blood compartment. Introduction of bone marrow cells overexpressing human MSR1 in apoE-deficient mice induced a significant reduction in serum cholesterol levels of ≈20% (
P
<0.001, 2-way ANOVA) as the result of a decrease in VLDL cholesterol. It is suggested that the reduction in VLDL cholesterol levels is due to increased clearance of modified lipoproteins by the overexpressed MSR1 in Kupffer cells of the liver, thereby protecting the arterial wall against the proatherogenic action of modified lipoproteins.
Sphingomyelinase Converts Lipoproteins From Apolipoprotein E Knockout Mice Into Potent Inducers of Macrophage Foam Cell Formation
Authors: Marathe Sudhir , Choi Yunsook , Leventhal Andrew R. , Tabas Ira
Published: June 2011

Abstract
—The apoE knockout (E0) mouse is one of the most widely used animal models of atherosclerosis, and there may be similarities to chylomicron remnant–induced atherosclerosis in humans. Although the lesions of these mice contain large numbers of cholesteryl ester (CE)-laden macrophages (foam cells), E0 plasma lipoproteins are relatively weak inducers of cholesterol esterification in macrophages. Previous in vivo work has suggested that arterial wall sphingomyelinase (SMase) may promote atherogenesis in the E0 mouse, perhaps by inducing subendothelial lipoprotein aggregation and subsequent foam cell formation. The goal of the present study was to test the hypothesis that the modification of E0 lipoproteins by SMase converts these lipoproteins into potent inducers of macrophage foam cell formation. When d<1.063 E0 lipoproteins were pretreated with SMase and then incubated with E0 macrophages, cellular CE mass and stimulation of the cholesterol esterification pathway were increased ≈5-fold compared with untreated lipoproteins. SMase-treated E0 lipoproteins were more potent stimulators of cholesterol esterification than either E0 lipoproteins in the presence of lipoprotein lipases or oxidized E0 lipoproteins. The uptake and degradation of SMase-treated E0 lipoproteins by macrophages were saturable and specific and substantially inhibited by partial proteolysis of cell-surface proteins. Uptake and degradation were diminished by an anti-apoB antibody and by competition with human S
f
100-400 hypertriglyceridemic VLDL, raising the possibility that a receptor that recognizes apoB-48 might be involved. In conclusion, SMase-modification of E0 lipoproteins, a process previously shown to occur in lesions, may be an important mechanism for foam cell formation in this widely studied model of atherosclerosis. Moreover, the findings in this report may provide important clues regarding the atherogenicity of chylomicron remnants in humans.
Inhibition of Mast Cell–Dependent Conversion of Cultured Macrophages Into Foam Cells With Antiallergic Drugs
Authors: Ma Hua , Kovanen Petri T.
Published: June 2011

Abstract
—Degranulation of isolated, rat peritoneal mast cells in the presence of low density lipoprotein (LDL) induces cholesteryl ester accumulation in cocultured macrophages with ensuing foam cell formation. This event occurs when the macrophages phagocytose LDL particles that have been bound to the heparin proteoglycans of exocytosed granules. In an attempt to inhibit such foam cell formation pharmacologically, rat peritoneal mast cells that had been passively sensitized with anti–ovalbumin-IgE were treated with 2 mast cell–stabilizing antianaphylactic drugs, MY-1250 or disodium cromoglycate (DSCG). Both drugs were found to inhibit antigen (ovalbumin)-triggered release of histamine from the mast cells, revealing mast cell stabilization. In cocultures of rat peritoneal macrophages and passively sensitized mast cells, addition of MY-1250 before addition of the antigen resulted in parallel reductions in histamine release from mast cells, uptake of [
14
C]sucrose-LDL, and accumulation of LDL-derived cholesteryl esters in the cocultured macrophages. Similarly, when passively sensitized mast cells were stimulated with antigen in the presence of DSCG and the preconditioned media containing all substances released from the drug-treated mast cells were collected and added to macrophages cultured in LDL-containing medium, uptake and esterification of LDL cholesterol by the macrophages were inhibited. The inhibitory effects of both drugs were mast cell–specific because neither drug inhibited the ability of macrophages to take up and esterify LDL cholesterol. Analysis of heparin proteoglycan contents of the incubation media revealed that both drugs had inhibited mast cells from expelling their granule remnants. Thus, both MY-1250 and DSCG prevent mast cells from releasing the heparin proteoglycan–containing vehicles that bind LDL and carry it into macrophages. This study suggests that antiallergic pharmacological agents could be used in animal models to prevent mast cell–dependent formation of foam cells in vivo.
Inducible Expression of Manganese Superoxide Dismutase by Phorbol 12-Myristate 13-Acetate Is Mediated by Sp1 in Endothelial Cells
Authors: Tanaka Toru , Kurabayashi Masahiko , Aihara Yasushi , Ohyama Yoshio , Nagai Ryozo
Published: June 2011

Abstract
—The expression of manganese superoxide dismutase (Mn-SOD), an important component of the cellular defense system against oxidative stress, is induced in response to a variety of stimuli, including cytokines and phorbol esters, in endothelial cells. To define the molecular mechanisms regulating the expression of Mn-SOD, we have characterized the promoter of the human Mn-SOD gene. In calf pulmonary artery endothelial cells, phorbol 12-myristate 13-acetate (PMA) gradually increased Mn-SOD mRNA levels, with a peak at 6 to 12 hours after stimulation. The increase in Mn-SOD mRNA was significantly inhibited by a protein kinase C (PKC) inhibitor (calphostin C) but not by a mitogen-activated protein kinase kinase-1 inhibitor (PD98059) or a p38 mitogen-activated protein kinase inhibitor (SB203580). By reporter gene transfection experiments of a series of promoter deletions and site-directed mutation constructs, we found 2 consensus Sp1 binding sequences located at −97 and at −77 to play an important role in PMA-induced Mn-SOD transcription. Electrophoretic gel mobility shift assays have indicated that this sequence serves as an Sp1 binding site. Northern and Western blot analysis has revealed that PMA-induced promoter activity of Mn-SOD correlates with an increased expression of Sp1. Nuclear proteins from PMA-treated calf pulmonary artery endothelial cells displayed an increased DNA binding to the Sp1 site. Furthermore, the Mn-SOD promoter was activated either by overexpression of Sp1 or the constitutively activated form of PKCβ in an Sp1 site–dependent manner. These results suggest that PMA stimulates transcription of the Mn-SOD gene through an increase in Sp1 expression and thus implicate Sp1 as an effector mediating the PKC-signaling pathway elicited by extracellular signals.
Complete Atherosclerosis Regression After Human ApoE Gene Transfer in ApoE-Deficient/Nude Mice
Authors: Desurmont Caroline , Caillaud Jean-Michel , Emmanuel Florence , Benoit Patrick , Fruchart Jean Charles , Castro Graciela , Branellec Didier , Heard Jean-Michel , Duverger Nicolas
Published: June 2011

Abstract
—The apolipoprotein E (apoE)-deficient mouse is a relevant animal model of human atherosclerosis. Although the prevention of atherosclerosis development has been documented after somatic gene transfer into animal models, regression of lesions remains to be demonstrated. Thus, we used this genetically defined mouse model nn the nude background to show atherosclerosis regression. ApoE-deficient nude mice were infected with 5×10
8
or 10
9
plaque-forming units of a first-generation adenovirus encoding human apoE cDNA. The secretion of human apoE resulted in a rapid decrease of total cholesterol, which normalized the hypercholesterolemic phenotype within 14 days (from 600±100 to <100 μg/mL). Transgene expression was observed during a period of >4 months, with a normalization of cholesterol and triglyceride levels during 5 months. At that time, we successfully reinjected the recombinant adenovirus and observed the appearance of the human protein as well as the correction of lipoprotein phenotype. In mice killed 6 months-after the first infection, we observed a dose-dependent regression of fatty streak lesions in the aorta. We showed sustained expression of a transgene with a first-generation adenoviral vector and a correction of dyslipoproteinemia phenotype leading to lesion regression. These data demonstrate that somatic gene transfer can induce plaque regression.
LCAT Modulates Atherogenic Plasma Lipoproteins and the Extent of Atherosclerosis Only in the Presence of Normal LDL Receptors in Transgenic Rabbits
Authors: Brousseau Margaret E. , Kauffman Richard D. , Herderick Edward E. , Demosky Stephen J. , Evans Wende , Marcovina Santica , Santamarina-Fojo Silvia , Brewer H. Bryan , Hoeg Jeffrey M.
Published: June 2011

Abstract
—Elevated low density lipoprotein cholesterol (LDL-C) and reduced high density lipoprotein cholesterol (HDL-C) concentrations are independent risk factors for coronary heart disease. We have previously demonstrated that overexpression of an enzyme with a well established role in HDL metabolism, lecithin:cholesterol acyltransferase (LCAT), in New Zealand White rabbits not only raises HDL-C concentrations but reduces those of LDL-C as well, ultimately preventing diet-induced atherosclerosis. In the present study, the human LCAT gene (hLCAT) was introduced into LDL receptor (LDLr)–deficient (Watanabe heritable hyperlipidemic) rabbits to (1) investigate the role of the LDLr pathway in the hLCAT-mediated reductions of LDL-C and (2) determine the influence of hLCAT overexpression on atherosclerosis susceptibility in an animal model of familial hypercholesterolemia. Heterozygosity or homozygosity for the LDLr defect was determined by polymerase chain reaction, and 3 groups of hLCAT-transgenic (hLCAT+) rabbits that differed in LDLr status were established: (1) LDLr wild-type (LDLr+/+), (2) LDLr heterozygotes (LDLr+/−), and (3) LDLr homozygotes (LDLr−/−). Data for hLCAT+ rabbits were compared with those of nontransgenic (hLCAT−) rabbits of the same LDLr status. Plasma HDL-C concentrations were significantly elevated in the hLCAT+ animals of each LDLr status. However, LDL-C levels were significantly reduced only in hLCAT+/LDLr+/+ and hLCAT+/LDLr+/− rabbits but not in hLCAT+/LDLr−/− rabbits (405±14 versus 392±31 mg/dL). Metabolic studies revealed that the fractional catabolic rate (FCR, d
−1
) of LDL apolipoprotein (apo) B-100 was increased in hLCAT+/LDLr+/+ (26±4 versus 5±0) and hLCAT+/LDLr+/− (4±1 versus 1±0) rabbits, whereas the FCR of LDL apoB-100 in both groups of LDLr−/− rabbits was nearly identical (0.16±0.02 versus 0.15±0.02). Consistently, neither aortic lipid concentrations nor the extent of aortic atherosclerosis was significantly different between hLCAT+/LDLr−/− and hLCAT−/LDLr−/− rabbits. Significant correlations were observed between the percent of aortic atherosclerosis and both LDL-C (
r
=0.985) and LDL apoB-100 FCR (−0.745), as well as between LDL-C and LDL apoB-100 FCR (−0.866). These data are the first to establish that LCAT modulates LDL metabolism via the LDLr pathway, ultimately influencing atherosclerosis susceptibility. Moreover, LCAT’s antiatherogenic effect requires only a single functional LDLr allele, identifying LCAT as an attractive gene therapy candidate for the majority of dyslipoproteinemic patients.
Stanol Ester Margarine Alone and With Simvastatin Lowers Serum Cholesterol in Families With Familial Hypercholesterolemia Caused by the FH–North Karelia Mutation
Authors: Vuorio Alpo F. , Gylling Helena , Turtola Hannu , Kontula Kimmo , Ketonen Pirjo , Miettinen Tatu A.
Published: June 2011

Abstract
—In heterozygous familial hypercholesterolemia (FH), serum low density lipoprotein (LDL) cholesterol levels are already elevated at birth. Premature coronary heart disease occurs in ≈30% of heterozygous untreated adult patients. Accordingly, to retard development of atherosclerosis, preventive measures for lowering cholesterol should be started even in childhood. To this end, 19 FH families consumed dietary stanol ester for 3 months. Stanol ester margarine lowers the serum cholesterol level by inhibiting cholesterol absorption. Each individual in the study replaced part of his or her daily dietary fat with 25 g of 80% rapeseed oil margarine containing stanol esters (2.24 g/d stanols, mainly sitostanol). The families who consumed this margarine for 12 weeks included 24 children, aged 3 to 13 years, with the North Karelia variant of FH (FH-NK), 4 FH-NK parents, and 16 healthy family members, and a separate group of 12 FH-NK adults who consumed the margarine for 6 weeks and who were on simvastatin therapy (20 or 40 mg/d). Fat-soluble vitamins were measured by high-pressure liquid chromatography, and cholesterol precursor sterols (indexes of cholesterol synthesis) and cholestanol and plant sterols (indexes of cholesterol absorption efficiency) were assayed by gas-liquid chromatography. No side effects occurred. Serum LDL cholesterol levels were reduced by 18% (
P
<0.001), 11%, 12% (
P
<0.001), and 20% (
P
<0.001) in the 4 groups, respectively. The serum campesterol-to-cholesterol ratios fell by 31% (
P
<0.001), 29%, 23% (
P
<0.001), and 36% (
P
<0.001), respectively, suggesting that cholesterol absorption efficiency was inhibited. Serum lathosterol ratios were elevated by 38% (
P
<0.001), 11%, 15% (
P
<0.001), and 19% (
P
<0.001), respectively, suggesting that cholesterol synthesis was compensatorily upregulated. The FH-NK children increased their serum lathosterol ratio more than did the FH-NK adults treated with stanol ester margarine and simvastatin (
P
<0.01). In the FH-NK children, serum retinol concentration and α-tocopherol–to-cholesterol ratios were unchanged by stanol ester margarine, but α- and β-carotene concentrations and ratios were decreased. As assayed in a genetically defined population of FH patients, a dietary regimen with stanol ester margarine proved to be a safe and effective hypolipidemic treatment for children and adults. In FH-NK adults on simvastatin therapy, serum LDL cholesterol levels could be reduced even further by including a stanol ester margarine in the regimen.
Insulin Therapy Improves Endothelial Function in Type 2 Diabetes
Authors: Vehkavaara Satu , Mäkimattila Sari , Schlenzka Anna , Vakkilainen Juha , Westerbacka Jukka , Yki-Järvinen Hannele
Published: June 2011

Abstract
—A total of 75 in vivo endothelial function tests (intrabrachial artery infusions of endothelium-dependent [acetylcholine] and -independent [sodium nitroprusside] vasoactive agents) were performed in 18 type 2 diabetic patients (aged 58±2 years, body mass index 28.5±0.6 kg/m
2
, and fasting plasma glucose 229±11 mg/dL) and 27 matched normal subjects. These tests were performed before and 6 months after combination therapy with insulin and metformin and before and 6 months after metformin therapy only. Before insulin therapy, blood flow responses to acetylcholine (15 μg/min) were significantly blunted in type 2 diabetic patients (7.5±0.7 mL · dL
−1
· min
−1
) compared with normal subjects (11.6±0.9 mL · dL
−1
· min
−1
,
P
<0.01). During insulin therapy, the acetylcholine response increased by 44% to 10.8±1.6 mL · dL
−1
· min
−1
(
P
<0.05). Insulin therapy also significantly increased the blood flow responses to both low and high doses of sodium nitroprusside. We conclude that insulin therapy improves endothelium-dependent and -independent vasodilatation. These data support the idea that insulin therapy has beneficial rather than harmful effects on vascular function.
Fluid Shear Stress Induces Heat Shock Protein 60 Expression in Endothelial Cells In Vitro and In Vivo
Authors: Hochleitner Boris-Wolfgang , Hochleitner Elisabeth-Olga , Obrist Peter , Eberl Thomas , Amberger Albert , Xu Qingbo , Margreiter Raimund , Wick Georg
Published: June 2011

Abstract
—Recent investigations indicate that the initial event in the pathogenesis of atherosclerosis involves an (auto)immunologic injury to the vessel wall. Heat shock proteins (hsps), which are expressed on the endothelial cell surface, constitute possible autoantigens. After being exposed to shear stress of 30 dyne/cm
2
in vitro by means of a rotational viscometer, human umbilical vein endothelial cells were immunohistochemically stained for hsp 60 by the monoclonal antibody ML-30; static control cells were negative. Maximal hsp 60 induction was observed after 12 hours of hemodynamic stress. In Northern blots, the level of hsp 60 mRNA was markedly increased after only 1 hour of shear stress in human umbilical vein endothelial cells compared with static control cells. In vivo investigations in Lewis rats confirmed these in vitro findings: the intima and media of frozen sections of the right common carotid artery exposed to increased wall shear stress (after ligation of the left common carotid artery) were stained for hsp 60. The vessel wall of the left low-shear-stress–exposed side was negative. These findings demonstrate that shear stress results in hsp 60 induction in endothelial cells in vivo and in vitro, providing the prerequisite for humoral and cellular reactions to endothelial hsp in the earliest stages of atherosclerosis.
Local Delivery of Platelet-Derived Growth Factor Receptor–Specific Tyrphostin Inhibits Neointimal Formation in Rats
Authors: Fishbein Ilia , Waltenberger Johannes , Banai Shmuel , Rabinovich Laura , Chorny Michael , Levitzki Alexander , Gazit Aviv , Huber Rita , Mayr Ulrike , Gertz S. David , Golomb Gershon
Published: June 2011

Abstract
—Signal transduction through the platelet-derived growth factor (PDGF)/PDGF receptor (PDGFR) system is involved in the process of postangioplasty restenosis. Tyrphostins are low molecular weight inhibitors of protein tyrosine kinases. We assessed the antiproliferative effects of PDGFRβ-specific tyrphostin AG-1295 in vitro and in vivo. AG-1295 significantly inhibited rat smooth muscle cell growth stimulated by PDGF-BB or FCS. This antiproliferative effect was paralleled by reversible reduction of the total phosphotyrosine level and the degree of PDGFRβ phosphorylation by the drug in vitro. Local sustained delivery of the drug from perivascularly implanted polymeric matrices resulted in focal AG-1295 levels of 711 and 29.1 ng/mg of dry arterial tissue 1 and 14 days after implantation in rats. AG-1295 delivered from polymeric matrices resulted in a 35% reduction of neointimal formation on day 14 after balloon injury in the rat carotid model. Tyrosine phosphorylation of certain transduction proteins in arterial tissue extracts was significantly upregulated by balloon injury on day 3 but was essentially returned to or below basal levels 14 days after injury. Tyrphostin treatment decreased tyrosine phosphorylation at both time points below the basal levels. Moreover, the enhancement of PDGFRβ expression 3 and 14 days after arterial injury was strongly inhibited by AG-1295 treatment. It can be concluded that AG-1295 reduces neointimal formation by inhibiting PDGFβ-triggered tyrosine phosphorylation.
Plasma Levels of Extracellular Superoxide Dismutase in an Australian Population
Authors: Mahaney Michael C. , Czerwinski Stefan A. , Adachi Tetsuo , Wilcken David E. L. , Wang Xing Li
Published: June 2011

Abstract
—Extracellular superoxide dismutase (EC-SOD) is a major superoxide scavenger and may be important to normal vascular function and cardiovascular health. We analyzed family data from 610 healthy Australians to detect and quantify the effects of genes on normal variation in plasma levels of EC-SOD and to test for pleiotropy with plasma nitric oxide (NO) and apolipoprotein A-I (apoA-I). Using maximum-likelihood–based variance decomposition methods, we determined that sex, age, and plasma levels of HDL cholesterol, apoA-I, and creatinine accounted for 38.6% of the variance in plasma EC-SOD levels and that additive genes accounted for 35% (
P
<0.00002). Multivariate analyses of plasma levels of EC-SOD, NO
x
(a measure of basal NO production), and apoA-I detected significant genetic correlations, indicating pleiotropy between EC-SOD and apoA-I (genetic correlation [ρ
G
]=−0.45) and between NO
x
and apoA-I (ρ
G
=0.58) but not between EC-SOD and NO
x
. Genes shared by EC-SOD and apoA-I account for 20% of the genetic variance and, respectively, 7% and 9% of the phenotypic variance in both traits. Shared genes also account for >33% of the genetic variance and 5% and 15% of the respective phenotypic variance in NO
x
and apoA-I. In healthy individuals, over a third of the variance in EC-SOD plasma levels is due to the additive effects of genes. Some genes influence EC-SOD and apoA-I levels. The same is true of NO
x
and apoA-I but not of EC-SOD and NO
x
. These patterns of pleiotropy can guide subsequent attempts to identify the genes and physiological mechanisms underlying them.
In Vivo Uptake of Radiolabeled MDA2, an Oxidation-Specific Monoclonal Antibody, Provides an Accurate Measure of Atherosclerotic Lesions Rich in Oxidized LDL and Is Highly Sensitive to Their Regression
Authors: Tsimikas Sotirios , Shortal Brian P. , Witztum Joseph L. , Palinski Wulf
Published: June 2011

Abstract
—To determine whether labeled antibodies against oxidized LDL (OxLDL) offer advantages for quantifying atherosclerosis, we compared in vivo aortic uptake of
125
I-labeled MDA2, a monoclonal antibody against malondialdehyde-lysine epitopes), atherosclerotic surface area, and aortic weight in Watanabe heritable hyperlipidemic and New Zealand White rabbits and in low density lipoprotein receptor–deficient (LDLR
−/−
) and apolipoprotein E–deficient (apoE
−/−
) mice. Absolute and specific uptakes of
125
I-MDA2 were significantly greater in plaque than in normal aortas. Uptake of
125
I-MDA2 significantly correlated with aortic weight and percent atherosclerotic surface area in rabbits and mice. To assess whether
125
I-MDA2 uptake reflects changes in lesion content of OxLDL, in a separate study, extensive atherosclerosis was induced in 4 groups of LDLR
−/−
mice by feeding them a high fat/cholesterol diet for 6 months. A baseline group was euthanized at this time. The remaining groups were fed “regression” diets (chow or chow+1% vitamin E+0.05% vitamin C) or the high fat/cholesterol diet for 6 more months. When atherosclerosis was measured as percent surface area or aortic weight, there was strong progression in the high fat/cholesterol group, moderate progression in the chow group, and no progression in the chow+vitamin E+vitamin C group compared with the baseline group. The
125
I-MDA2 method also yielded a significant increase in atherosclerosis in the high fat/cholesterol group but significant decreases in the chow and chow+vitamin E+vitamin C groups. Immunocytochemistry showed fewer oxidation-specific epitopes in lesions from the chow and chow+vitamin E+vitamin C groups. Thus, the uptake of
125
I-MDA2 correlates well with traditional measures of atherosclerosis but also reflects reduced plaque OxLDL content after hypocholesterolemic intervention.
Cholesterol-Lowering Treatment Is Associated With Improvement in Coronary Vascular Remodeling and Endothelial Function in Patients With Normal or Mildly Diseased Coronary Arteries
Authors: Hamasaki Shuichi , Higano Stuart T. , Suwaidi Jassim Al , Nishimura Rick A. , Miyauchi Katsumi , Holmes David R. , Lerman Amir
Published: June 2011

Abstract
— Coronary vascular remodeling and altered endothelial function have been described in the early stages of native atherosclerosis. The purpose of this study was to evaluate the association between cholesterol-lowering therapy and coronary vascular remodeling and endothelial function in patients with normal or mildly diseases coronary arteries. Patients (N=101) with normal or mildly diseased coronary arteries by coronary angiography underwent intravascular ultrasound examination of the left anterior descending coronary artery. Vessel and lumen area, atherosclerotic plaque area, and plaque morphology were evaluated. Vascular reactivity was examined with the use of intracoronary adenosine, acetylcholine, and nitroglycerin. Patients were divided into 3 groups based on the total cholesterol levels: group 1 (n=25), patients with a history of hypercholesterolemia adequately treated (total cholesterol <240 mg/dL); group 2 (n=26), patients with hypercholesterolemia not adequately controlled (total cholesterol ≥240 mg/dL); and group 3 (n=50), patients without hypercholesterolemia. Vessel area and lumen area were significantly greater in groups 1 and 3 than in group 2 (for respective values in groups 1, 2, and 3: vessel area 11.9±0.5, 10.6±0.4, and 11.8±0.4 mm
2
, both
P
<0.05; lumen area 8.3±0.4, 6.9±0.3, and 8.9±0.3 mm
2
, both
P
<0.01). However, plaque areas in groups 1 and 2 were similar. Furthermore, acetylcholine-induced percent increases in coronary blood flow were significantly greater in groups 1 and 3 than in group 2 (for respective values in groups 1, 2, and 3: 70.5±20.1%, 22.8±13.7%, and 68.6±14.8%, both
P
<0.05). Cholesterol-lowering treatment is associated with an improvement in coronary lumen area that results not from a decrease in plaque area but from an increase in vessel area, reflecting vascular remodeling. Additionally, this adaptive process may occur in association with an improvement of endothelium-dependent vasodilation of the resistance coronary artery.
Not Acute but Chronic Hypertriglyceridemia Is Associated With Impaired Endothelium-Dependent Vasodilation
Authors: de Man Frits H. , Weverling-Rijnsburger Annelies W. E. , van der Laarse Arnoud , Smelt Augustinus H. M. , Jukema J. Wouter , Blauw Gerard J.
Published: June 2011

Abstract
—There is controversy regarding the relation between hypertriglyceridemia (HTG) and endothelial function. This study was designed to investigate endothelial function in a patient group with chronic HTG, before and during lipid-lowering therapy by atorvastatin. In addition, the effects of acute HTG on endothelial function were studied in normolipidemic individuals. Eight male patients with chronic HTG were studied before and after 6 weeks of lipid-lowering treatment with 80 mg atorvastatin once daily. Ten age-matched control subjects were studied at baseline and immediately after a high-dose infusion of artificial triglycerides. The endothelium-dependent response to serotonin was attenuated in the HTG group, whereas the response to acetylcholine was comparable to the response in the control group. The response to the endothelium-independent vasodilator nitroprusside was comparable in both groups. In response to atorvastatin therapy, serum triglyceride and cholesterol levels decreased significantly by 43% (paired
t
test,
P
=0.017) and 38% (paired
t
test,
P
=0.012), respectively. After 6 weeks of treatment, the forearm blood flow response to serotonin improved from 63% to 106% (ANOVA,
P
<0.001). Induction of acute HTG in the control subjects did not affect the forearm blood flow responses to serotonin and nitroprusside; however, the response to acetylcholine was paradoxically increased. In conclusion, patients with chronic HTG have an impaired endothelium-dependent vasodilation to serotonin that is normalized after 6 weeks of lipid-lowering therapy by atorvastatin.
Apolipoprotein A-I and A-II Kinetic Parameters as Assessed by Endogenous Labeling With [
2
H
3
]Leucine in Middle-Aged and Elderly Men and Women
Authors: Velez-Carrasco Wanda , Lichtenstein Alice H. , Li Zhengling , Dolnikowski Gregory G. , Lamon-Fava Stefania , Welty Francine K. , Schaefer Ernst J.
Published: June 2011

Abstract
—The purpose of our study was to investigate high density lipoprotein (HDL) apolipoprotein (apo) A-I and apoA-II kinetics in a state of constant feeding after a primed-constant infusion of [5,5,5-
2
H
3
]
l
-leucine in 32 normolipidemic older men and postmenopausal women (aged 41 to 79 years). ApoA-I and apoA-II were isolated from plasma HDL, and enrichment was determined by gas chromatography/mass spectrometry. The fractional secretion rate was obtained by using a monoexponential equation calculated with the SAAM II program (Department of Bioengineering, University of Washington, Seattle). Mean HDL cholesterol (HDL-C) and total triglyceride levels were 23% higher and 27% lower, respectively, in women than in men. Mean plasma apoA-I levels were 10% greater in women than in men, whereas mean apoA-II levels were similar. HDL size, estimated by gradient-sizing gels and by the HDL-C/apoA-I+apoA-II ratio, was significantly higher in women than in men. Mean apoA-I secretion rates (SRs) were similar in men and women (12.28±3.64 versus 11.96±2.92 mg/kg per day), whereas there was a trend toward a lower (−13%) apoA-I fractional catabolic rate (FCR) in women compared with men (0.199±0.037 versus 0.225±0.062 pools per day,
P
=0.11). Mean apoA-II SRs (2.21±0.57 versus 2.27±0.91 mg/kg per day) and FCRs (0.179±0.034 versus 0.181±0.068 pools per day) were similar in men and women. For the group as a whole, there was an inverse association between the HDL-C/apoA-I+apoA-II ratio and apoA-I FCR and between the ratio and triglyceride levels. Plasma levels of apoA-I and apoA-II were correlated with their respective SRs but not FCRs. These data suggest a major role for apoA-I and apoA-II SRs in regulating the plasma levels of these proteins, whereas apoA-I FCR might be an important factor contributing to the differences in apoA-I levels between men and postmenopausal women. Moreover, plasma triglyceride levels are important determinants of HDL size and apoA-I catabolism.
LDL Cholesterol as a Strong Predictor of Coronary Heart Disease in Diabetic Individuals With Insulin Resistance and Low LDL
Authors: Howard Barbara V. , Robbins David C. , Sievers Maurice L. , Lee Elisa T. , Rhoades Dorothy , Devereux Richard B. , Cowan Linda D. , Gray R. Stuart , Welty Thomas K. , Go Oscar T. , Howard Wm. James
Published: June 2011

Abstract
—Diabetes has been shown to increase the risk of coronary heart disease in all populations studied. However, there is a lack of information on the relative importance of diabetes-associated risk factors for cardiovascular disease (CVD), especially the role of lipid levels, because low density lipoprotein (LDL) cholesterol often is not elevated in diabetic individuals. The objective of this analysis was to evaluate CVD risk factors in a large cohort of diabetic individuals and to compare the importance of dyslipidemia (ie, elevated triglycerides and low levels of high density lipoprotein [HDL] cholesterol) and LDL cholesterol in determining CVD risk in diabetic individuals. The Strong Heart Study assesses coronary heart disease and its risk factors in American Indians in Arizona, Oklahoma, and South/North Dakota. The baseline clinical examinations (July 1989 to January 1992) consisted of a personal interview, physical examination, and drawing of blood samples for 4549 study participants (2034 with diabetes), 45 to 74 years of age. Follow-up averaged 4.8 years. Fatal and nonfatal CVD events were confirmed by standardized record review. Participants with diabetes, compared with those with normal glucose tolerance, had lower LDL cholesterol levels but significantly elevated triglyceride levels, lower HDL cholesterol levels, and smaller LDL particle size. Significant independent predictors of CVD in those with diabetes included age, albuminuria, LDL cholesterol, HDL cholesterol (inverse), fibrinogen, and percent body fat (inverse). A 10-mg/dL increase in LDL cholesterol was associated with a 12% increase in CVD risk. Thus, even at concentrations well below the National Cholesterol Education Program target of 130 mg/dL, LDL cholesterol is a strong independent predictor of coronary heart disease in individuals with diabetes, even when components of diabetic dyslipidemia are present. These results support recent recommendations for aggressive control of LDL cholesterol in diabetic individuals, with a target level of <100 mg/dL.
Atherosclerosis Progression in LDL Receptor–Deficient and Apolipoprotein E–Deficient Mice Is Independent of Genetic Alterations in Plasminogen Activator Inhibitor-1
Authors: Sjöland Helén , Eitzman Daniel T. , Gordon David , Westrick Randal , Nabel Elizabeth G. , Ginsburg David
Published: June 2011

Abstract
—Impaired fibrinolysis has been linked to atherosclerosis in a number of experimental and clinical studies. Plasminogen activator inhibitor type 1 (PAI-1) is the primary inhibitor of plasminogen activation and has been proposed to promote atherosclerosis by facilitating fibrin deposition within developing lesions. We examined the contribution of PAI-1 to disease progression in 2 established mouse models of atherosclerosis. Mice lacking apolipoprotein E (apoE−/−) and mice lacking the low density lipoprotein receptor (LDLR−/−) were crossbred with transgenic mice overexpressing PAI-1 (resulting in PAI-1 Tg
+
/apoE−/− and PAI-1 Tg
+
/LDLR−/−, respectively) or were crossbred with mice completely deficient in PAI-1 gene expression (resulting in PAI-1−/−/apoE−/− and PAI-1−/−/LDLR−/−, respectively). All animals were placed on a western diet (21% fat and 0.15% cholesterol) at 4 weeks of age and analyzed for the extent of atherosclerosis after an additional 6, 15, or 30 weeks. Intimal and medial areas were determined by computer-assisted morphometric analysis of standardized microscopic sections from the base of the aorta. Atherosclerotic lesions were also characterized by histochemical analyses with the use of markers for smooth muscle cells, macrophages, and fibrin deposition. Typical atherosclerotic lesions were observed in all experimental animals, with greater severity at the later time points and generally more extensive lesions in apoE−/− than in comparable LDLR−/− mice. No significant differences in lesion size or histological appearance were observed among PAI-1−/−, PAI-1 Tg
+
, or PAI-1 wild-type mice at any of the time points on either the apoE−/− or LDLR−/− genetic background. We conclude that genetic modification of PAI-1 expression does not significantly alter the progression of atherosclerosis in either of these well-established mouse models. These results suggest that fibrinolytic balance (as well as the potential contribution of PAI-1 to the regulation of cell migration) plays only a limited role in the pathogenesis of the simple atherosclerotic lesions observed in the mouse.
In Vivo Dynamic Real-Time Monitoring and Quantification of Platelet-Thrombus Formation
Authors: Zaman Azfar G. , Osende Julio I. , Chesebro James H. , Fuster Valentin , Padurean Adrian , Gallo Richard , Worthley Stephen G. , Helft Gerard , Rodriguez Oswaldo X. , Fallon John T. , Badimon Juan J.
Published: June 2011

Abstract
—Current methods for monitoring thrombosis and thrombus growth are invasive and provide only single–time-point data. Animal models rely mainly on flow changes as a surrogate of thrombus formation. Our aim was to validate a unique potentially noninvasive system to detect and quantify dynamic thrombus formation in vivo by using a porcine model of carotid artery injury. Thrombus growth was monitored by deposition of autologous
111
In-labeled platelet activity over the injured artery by use of miniaturized gamma detectors and Doppler blood flow. Counts were recorded at 2-minute intervals for 2 hours. The technique was validated by comparing standard antithrombotic agents against controls. Platelet recruitment was detected before significant change in flow. Thrombus formation, calculated as the area under the curve (platelets×minutes×10
6
), was greatest for control animals (11.7±1.28), followed by animals treated with aspirin (6.13±0.91,
P
<0.05), heparin (2.45±0.34,
P
<0.05), and hirudin (0.2±0.01,
P
<0.01 compared with heparin). The rate of platelet deposition was assessed as the slope of the curve in the first 30 minutes (platelets×10
6
per minute) for the following treatment groups of animals: control, 3.53±0.34; aspirin, 1.67±0.34 (
P
<0.01); heparin, 1.55±0.3 (
P
<0.01); and hirudin, 0.25±0.03 (
P
<0.001). There was no statistical difference between heparin and aspirin treatments. Change in flow was assessed as reduction from baseline: control, >99±0.34%; aspirin, 39±9.1%; heparin, 36±12.5%; and hirudin, 17±5.4%. There was no statistical difference between the aspirin- and heparin-treated groups. Morphometric analysis revealed >99±0.63% occlusion of the luminal area with thrombus for the control group, 43±14.3% for the aspirin-treated group, 30±5.6% for the heparin-treated group, and <10±1.8% for the hirudin-treated group. Assessment of platelet-thrombus formation with this technique was more sensitive than change in flow in determining antithrombotic efficacy, and thrombus formation was detected earlier. This study validates a new quantitative, sensitive, potentially noninvasive, portable, in vivo monitoring of dynamic thrombus growth, which appears applicable to phase II studies in humans.
P2Y Receptor Regulation of PAI-1 Expression in Vascular Smooth Muscle Cells
Authors: Bouchie Julie L. , Chen Hong-Chi , Carney Rebbeca , Bagot J. Courtney , Wilden Peter A. , Feener Edward P.
Published: June 2011

Abstract
—P2Y-type purine and pyrimidine nucleotide receptors play important roles in the regulation of vascular hemostasis. In this article, the regulation of plasminogen activator inhibitor-1 (PAI-1) expression in rat aortic smooth muscle cells (RASMCs) by adenine and uridine nucleotides was examined and compared. Northern analysis revealed that RASMCs express multiple P2Y receptor subtypes, including P2Y
1
, P2Y
2
, and P2Y
6
. Treatment of RASMCs with UTP increased PAI-1 mRNA expression and extracellular PAI-1 protein levels by 21-fold (
P
<0.001) and 7-fold (
P
<0.001), respectively. The ED
50
for the effect of UTP on PAI-1 expression was ≈1 μmol/L, and its maximal effect occurred at 3 hours. UDP stimulated a 5-fold increase (
P
<0.005) in PAI-1 expression. In contrast to these potent stimulatory effects of uridine nucleotides, ATP and 2-methylthioadenosine triphosphate (2-MeSATP) caused a small and transient increase in PAI-1 mRNA at 1 hour, followed by a rapid decrease to baseline levels. ADP produced only an inhibitory effect, reducing PAI-1 mRNA levels by 63% (
P
<0.05) at 3 hours. The relative nucleotide potency in stimulating PAI-1 expression is UTP>UDP>ATP=2-MeSATP, consistent with a predominant role of the P2Y
6
receptor. Further studies revealed that exposure of RASMCs to either ATP or ADP for 3 hours inhibited both UTP- and angiotensin II–stimulated PAI-1 expression by up to 90% (
P
<0.001). Thus, ATP induced a small and transient upregulation of PAI-1 that was followed by a strong inhibition of PAI-1 expression. These results show that extracellular adenine and uridine nucleotides exert potent and opposing effects on vascular PAI-1 expression.
Asymmetric Dimethylarginine Increases Mononuclear Cell Adhesiveness in Hypercholesterolemic Humans
Authors: Chan Jason R. , Böger Rainer H. , Bode-Böger Stefanie M. , Tangphao Oranee , Tsao Philip S. , Blaschke Terrence F. , Cooke John P.
Published: June 2011

Abstract
—Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is elevated in hypercholesterolemia. This study was designed to determine the role of ADMA in the increased mononuclear cell adhesiveness observed in human hypercholesterolemia. In patient studies, plasma ADMA levels were determined by high-performance liquid chromatography. Functional mononuclear leukocyte adhesion assays were performed in parallel, and flow cytometry was used to characterize bound monocytes and T lymphocytes. Hypercholesterolemic patients were then placed on an oral
l
-arginine regimen of 14 or 21 g/d and studied over 12 weeks. In cell culture studies, bovine aortic endothelial cells were incubated with varied concentrations of ADMA. Monocytoid cells were cocultured with these bovine aortic endothelial cells, and their adhesiveness was assessed by use of a binding assay. Flow cytometry was used to quantify adhesion molecule expression. Plasma ADMA levels and adhesiveness of mononuclear cells (specifically, monocytes and T lymphocytes) were elevated in hypercholesterolemic patients. Adhesiveness was inversely correlated with the plasma
l
-arginine/ADMA ratio. Oral administration of
l
-arginine normalized plasma
l
-arginine/ADMA ratios and attenuated monocyte and T-lymphocyte adhesiveness. ADMA had no direct effect on the adhesiveness of mononuclear cells. However, monocytes became hyperadhesive when cocultured with ADMA-exposed endothelial cells. In human hypercholesterolemia, the plasma
l
-arginine/ADMA ratio is inversely correlated with mononuclear cell adhesiveness. Restoration of the
l
-arginine/ADMA ratio to control levels normalizes mononuclear cell adhesiveness. Our studies suggest that the elaboration of endothelium-derived nitric oxide affects the behavior of circulating T lymphocytes and monocytes.
C-Reactive Protein, Cardiovascular Risk Factors, and Mortality in a Prospective Study in the Elderly
Authors: Strandberg Timo E. , Tilvis Reijo S.
Published: June 2011

Abstract
—Serum C-reactive protein (CRP) reflects inflammation and predicts cardiovascular disease in middle-aged individuals. We investigated CRP, risk factors, and 10-year mortality in 3 elderly cohorts (aged 75, 80, and 85 years; n=455) of the population-based Helsinki Ageing Study. Clinical and laboratory examinations were performed at baseline, and in 1998, CRP was measured by a sensitive method (sensitivity 0.3 mg/L) from frozen serum samples. Mortality data were retrieved from national registers. Serum CRP ranged from 0.18 to 170.0 mg/L (interquartile range 0.68 to 4.10 mg/L, median 1.60 mg/L). CRP correlated significantly with body mass index and plasma insulin and was associated with smoking at baseline. An inverse correlation was found with albumin and total and HDL cholesterol. CRP was not associated with diabetes or cardiovascular disease but was significantly (
P
=0.015) higher in persons with (n=70) than without (n=385) dementia. During the 10-year follow-up, 61% (n=278) of the cohort died; half of the deaths were due to cardiovascular diseases. Mean CRP in survivors and nonsurvivors was 3.16 and 5.22 mg/L (
P
=0.017), respectively. After controlling for age and sex, baseline CRP (per 10 mg/L) significantly predicted the 10-year total mortality (risk ratio 1.20, 95% CI 1.08 to 1.32) and cardiovascular mortality (risk ratio 1.22, 95% CI 1.10 to 1.35). Predictive value was found in the 75-year-old cohort, but it was clearly attenuated in the 80- and 85-year-old cohorts. The results indicate that CRP is associated with several cardiovascular risk factors in the elderly. CRP alone predicts overall and cardiovascular mortality, but the prediction was significant in only the 75-year-old cohort.
Detection of
Chlamydia pneumoniae
–Reactive T Lymphocytes in Human Atherosclerotic Plaques of Carotid Artery
Authors: Mosorin Martti , Surcel Heljä-Marja , Laurila Aino , Lehtinen Matti , Karttunen Riitta , Juvonen Jukka , Paavonen Jorma , Morrison Richard P. , Saikku Pekka , Juvonen Tatu
Published: June 2011

Abstract
—Linkage between
Chlamydia pneumoniae
infection and atherosclerosis has been confirmed in several studies, but the precise role of this organism in the disease process is not known. We investigated the relation and reactivity of T lymphocytes of human carotid plaques to
C pneumoniae
antigens. Tissue specimens were obtained from 17 patients who underwent carotid endarterectomy. Immunohistological staining and/or in situ hybridization revealed the presence of
C pneumoniae
in 11 (64%) of the 17 of the cases. Inflammatory infiltration seen in the vessel walls consisted primarily of CD45RO+ T-memory lymphocytes (median 80%, range 50% to 90%), whereas CD20+ B cells and monocytes were in minor proportion. In vivo activated T lymphocytes were propagated from the specimens with interleukin-2, and the antigen specificity of the established T-cell lines (TLLs) was analyzed against
C pneumoniae
elementary body antigen. TLLs were established from all 17 carotid tissues but none from the control specimens of ascending aorta.
C pneumoniae
was recognized as a specific T-cell–stimulating antigen in 7 (41%) of 17 cases. Further analyses of the
C pneumoniae
–reactive TLLs showed that chlamydial 60-kDa heat-shock protein induced specific proliferation in 5 (71%) of 7 cases and revealed 2 haplotype (DRB1*1502 and DQB1*06) binding motifs in human 60-kDa heat-shock protein.
C pneumoniae
was identified as a specific microbial antigen recognized by 41% of TLLs propagated from in vivo activated plaque T cells. Our results suggests that cell-mediated immunity to
C pneumoniae
plays a role in the atherosclerotic process and that this response may involve autoimmunity.