bluuebunny/crossref_metadata_2025 huggingface dataset:
Western-Type Diets Induce Insulin Resistance and Hyperinsulinemia in LDL Receptor-Deficient Mice But Do Not Increase Aortic Atherosclerosis Compared With Normoinsulinemic Mice in Which Similar Plasma Cholesterol Levels Are Achieved by a Fructose-Rich Diet
Authors: Merat Shiva , Casanada Florencia , Sutphin Mary , Palinski Wulf , Reaven Peter D.
Published: June 2011

Abstract
—The role of insulin resistance (IR) in atherogenesis is poorly understood, in part because of a lack of appropriate animal models. We assumed that fructose-fed LDL receptor-deficient (LDLR
−/−
) mice might be a model of IR and atherosclerosis because (1) fructose feeding induces hyperinsulinemia and IR in rats; (2) a preliminary experiment showed that fructose feeding markedly increases plasma cholesterol levels in LDLR
−/−
mice; and (3) hypercholesterolemic LDLR
−/−
mice develop extensive atherosclerosis. To test whether IR could be induced in LDLR
−/−
mice, 3 groups of male mice were fed a fructose-rich diet (60% of total calories; n=16), a fat-enriched (Western) diet intended to yield the same plasma cholesterol levels (n=18), or regular chow (n=7) for approximately 5.5 months. The average cholesterol levels of both hypercholesterolemic groups were similar (849±268 versus 964±234 mg/dL) and much higher than in the chow-fed group (249±21 mg/dL). Final body weights in the Western diet group were higher (39±6.2 g) than in the fructose- (27.8±2.7 g) or chow-fed (26.7±3.8 g) groups. Contrary to expectation, IR was induced in mice fed the Western diet, but not in fructose-fed mice. The Western diet group had higher average glucose levels (187±16 versus 159±12 mg/dL) and 4.5-fold higher plasma insulin levels. Surprisingly, the non–insulin-resistant, fructose-fed mice had significantly more atherosclerosis than the insulin-resistant mice fed Western diet (11.8±2.9% versus 7.8±2.5% of aortic surface;
P
<0.01). These results suggest that (1) fructose-enriched diets do not induce IR in LDLR
−/−
mice; (2) the Western diets commonly used in LDLR
−/−
mice may not only induce atherosclerosis, but also IR, potentially complicating the interpretation of results; and (3) IR and hyperinsulinemia do not enhance atherosclerosis in LDLR
−/−
mice, at least under conditions of very high plasma cholesterol levels. The fact that various levels of hypercholesterolemia can be induced in LDLR
−/−
mice by fat-enriched diets and that such diets induce IR and hyperinsulinemia suggest that LDLR
−/−
mice may be used as models to elucidate the effect of IR on atherosclerosis, eg, by feeding them Western diets with or without insulin-sensitizing agents.
Fish Intake, Independent of Apo(a) Size, Accounts for Lower Plasma Lipoprotein(a) Levels in Bantu Fishermen of Tanzania
Authors: Marcovina Santica M. , Kennedy Hal , Bon Gabriele Bittolo , Cazzolato Giuseppe , Galli Claudio , Casiglia Edoardo , Puato Massimo , Pauletto Paolo
Published: June 2011

Abstract
—Plasma lipoprotein(a) [Lp(a)] levels are largely genetically determined by sequences linked to the gene encoding apolipoprotein(a) [apo(a)], the distinct protein component of Lp(a). Apo(a) is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 domain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. In 2 racially homogeneous Bantu populations from Tanzania differing in their dietary habits, we found that median plasma levels of Lp(a) were 48% lower in those living on a fish diet than in those living on a vegetarian diet. Considering the relationship between apo(a) size and Lp(a) plasma concentration, we have extensively evaluated apo(a) isoform distribution in the 2 populations to determine the impact of apo(a) size in the determination of Lp(a) values. The majority of individuals (82% of the fishermen and 80% of the vegetarians) had 2 expressed apo(a) alleles. Additionally, the fishermen had a high frequency of large apo(a) isoforms, whereas a higher frequency of small isoforms was found in the vegetarians. When subjects from the 2 groups were matched for apo(a) phenotype, the median Lp(a) value was 40% lower in Bantus on the fish diet than in those on the vegetarian diet. A significant inverse relationship was also found between plasma n-3 polyunsaturated fatty acids and Lp(a) levels (
r
=−0.24,
P
=0.01). The results of this study are consistent with the concept that a diet rich in n-3 polyunsaturated fatty acids, and not genetic differences, is responsible for the lower plasma levels of Lp(a) in the fish-eating Bantus and strongly suggest that a sustained fish-based diet is able to lower plasma levels of Lp(a).
Scavenger Receptor Activity Is Increased in Macrophages From Rabbits With Low Atherosclerotic Response:
Authors: Teupser Daniel , Stein Olga , Burkhardt Ralph , Nebendahl Klaus , Stein Yechezkiel , Thiery Joachim
Published: June 2011

Abstract—We have previously described 2 strains of New Zealand White rabbits with a high (HAR) or low (LAR) atherosclerotic response to hypercholesterolemia. In the present study, we focused on class A scavenger receptor (SR-A) activity and ApoE expression in macrophages from both rabbit strains. These parameters play a crucial role in maintaining cholesterol homeostasis in the arterial wall and may be involved in the development of atherosclerosis. SR activity, as measured by uptake of DiI-labeled acetylated LDL, was significantly higher in macrophages from LAR rabbits (2177±253 ng/mg cell protein) than in macrophages from HAR rabbits (1153±200 ng/mg cell protein). The higher SR activity was caused by a greater number of SRs (apparentVmax, 4100 ng/mg in LAR and 1980 ng/mg in HAR rabbits). The high SR activity in macrophages from LAR rabbits was associated with a significantly higher expression of SR-A mRNA compared with macrophages from HAR rabbits. However, the latter finding could not be explained by differences in the activity of transcription factor–activating protein 1 (AP-1), which was comparable in macrophages from both strains of rabbits. Because under certain circumstances SR-A mRNA expression is regulated in parallel with ApoE expression, we also evaluated this parameter. Although ApoE mRNA was 74% higher in macrophages from LAR rabbits, the difference did not reach statistical significance. In conclusion, the increased expression of SR-A in macrophages in the presence of adequate amounts of ApoE may play a role in attenuating atherosclerosis in LAR rabbits.
PAI-1 Produced Ex Vivo by Human Adipose Tissue Is Relevant to PAI-1 Blood Level
Authors: Morange P. E. , Alessi M. C. , Verdier M. , Casanova D. , Magalon G. , Juhan-Vague I.
Published: June 2011

Abstract
—Human adipose tissue has been shown to produce plasminogen activator inhibitor type 1 (PAI-1). However, the importance of adipose tissue in the regulation of the PAI-1 plasma level is not known. The aim of this study was to investigate the relation between the production of PAI-1 by adipose tissue, plasma PAI-1 level, and variables related to the insulin resistance state. The link between the production of PAI-1 inducers such as tumor necrosis factor-α and transforming growth factor-β and the production of PAI-1 by adipose tissue was also evaluated. Blood samples were obtained as soon as possible to the induction of anesthesia from 30 patients undergoing elective abdominoplasty. PAI-1 antigen levels measured in conditioned media after a 19-hour incubation period of adipose tissue explants were significantly correlated with plasma PAI-1 antigen levels (
r
=0.54,
P
=0.004) and with systemic lipid parameters such as triglycerides and high density lipoprotein cholesterol (
r
=0.46,
P
=0.014;
r
=−0.50,
P
=0.01, respectively) but not with insulinemia and body mass index. PAI-1 production by adipose tissue was correlated with those of TNF-α (
r
=0.5,
P
=0.01) and TGF-β (
r
=0.53,
P
=0.007). These results emphasize the role of adipose tissue in determining plasma levels of PAI-1, with a local contribution of TNF-α and TGF-β in PAI-1 production by adipose tissue.
Gallates Inhibit Cytokine-Induced Nuclear Translocation of NF-κB and Expression of Leukocyte Adhesion Molecules in Vascular Endothelial Cells
Authors: Murase Takatoshi , Kume Noriaki , Hase Tadashi , Shibuya Yusuke , Nishizawa Yoshinori , Tokimitsu Ichiro , Kita Toru
Published: June 2011

Abstract—Gallates (gallic acid esters) belong to the class of phenolic compounds, which are abundant in red wine. In this study, we show that gallates can inhibit cytokine-induced activation of nuclear factor κB (NF-κB) and thereby reduce expression of endothelial-leukocyte adhesion molecules in cultured human umbilical vein endothelial cells (HUVECs). Pretreatment of HUVECs with ethyl gallate (3 to 10 μmol/L) significantly suppressed interleukin-1α (IL-1α)– or tumor necrosis factor-α (TNF-α)– induced mRNA and cell-surface expression of vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and E-selectin, which was associated with reduced adhesion of leukocytes to HUVECs. Gel shift assays with the NF-κB consensus sequence showed the decreased densities of the shifted bands in gallate-treated HUVECs. Furthermore, gallate pretreatment inhibited cytokine-induced transcription of a fusion gene, which consisted of 4 repeats of the NF-κB consensus sequence and the luciferase reporter gene. Immunoblot analysis of nuclear extracts and whole-cell lysates demonstrated the decreased amounts of NF-κB p65 in nuclei but equal amounts of inhibitor-κBα (I-κBα) in whole-cell lysates of ethyl gallate–treated HUVECs. Incubation of the nuclear extracts from cytokine-activated HUVECs with ethyl gallate did not affect the NF-κB shifted bands induced by cytokines in gel shift assays. Taken together, these data demonstrate that ethyl gallate can inhibit cytokine-induced nuclear translocation of NF-κB p65 by way of a mechanism independent of I-κBα degradation and thereby suppress expression of VCAM-1, ICAM-1, and E-selectin, which was associated with reduced adhesion of leukocytes. These results in vitro demonstrate that gallates can exhibit anti-inflammatory properties by blocking activation of NF-κB and suggest that these natural compounds, abundant in red wine, may play important roles in the prevention of atherosclerosis and inflammatory responses in vivo.
All ApoB-Containing Lipoproteins Induce Monocyte Chemotaxis and Adhesion When Minimally Modified
Authors: Lee Chris , Sigari Farhad , Segrado Theresa , Hörkkö Sohvi , Hama Susan , Subbaiah P. V. , Miwa Masao , Navab Mohamad , Witztum Joseph L. , Reaven Peter D.
Published: June 2011

Abstract
—Mildly oxidized LDL has many proinflammatory properties, including the stimulation of monocyte chemotaxis and adhesion, that are important in the development of atherosclerosis. Although ApoB-containing lipoproteins other than LDL may enter the artery wall and undergo oxidation, very little is known regarding their proinflammatory potential. LDL, IDL, VLDL, postprandial remnant particles, and chylomicrons were mildly oxidized by fibroblasts overexpressing 15-lipoxygenase (15-LO) and tested for their ability to stimulate monocyte chemotaxis and adhesion to endothelial cells. When conditioned on 15-LO cells, LDL, IDL, but not VLDL increased monocyte chemotaxis and adhesion ≈4-fold. Chylomicrons and postprandial remnant particles were also bioactive. Although chylomicrons had a high 18:1/18:2 ratio, similar to that of VLDL, and should presumably be less susceptible to oxidation, they contained (in contrast to VLDL) essentially no platelet-activating factor acetylhydrolase (PAF-AH) activity. Because PAF-AH activity of lipoproteins may be reduced in vivo by oxidation or glycation, LDL, IDL, and VLDL were treated in vitro to reduce PAF-AH activity and then conditioned on 15-lipoxygenase cells. All 3 PAF-AH–depleted lipoproteins, including VLDL, exhibited increased stimulation of monocyte chemotaxis and adhesion. In a similar manner, lipoproteins from Japanese subjects with a deficiency of plasma PAF-AH activity were also markedly more bioactive, and stimulated monocyte adhesion nearly 2-fold compared with lipoproteins from Japanese control subjects with normal plasma PAF-AH. For each lipoprotein, bioactivity resided in the lipid fraction and monocyte adhesion could be blocked by PAF-receptor antagonists. These data suggest that the susceptibility of plasma lipoproteins to develop proinflammatory activity is in part related to their 18:1/18:2 ratio and PAF-AH activity, and that bioactive phospholipids similar to PAF are generated during oxidation of each lipoprotein. Moreover, LDL, IDL, postprandial remnant particles, and chylomicrons and PAF-AH–depleted VLDL all give rise to proinflammatory lipids when mildly oxidized.
Estrogen-Mediated Increases in LDL Cholesterol and Foam Cell–Containing Lesions in Human ApoB100×CETP Transgenic Mice
Authors: Zuckerman Steven H. , Evans Glenn F. , Schelm Judi A. , Eacho Patrick I. , Sandusky George
Published: June 2011

Abstract
—The murine double transgenic mouse expressing both human apoB100 and cholesteryl ester transfer protein (CETP), has been used as a model to understand the effects mediated by various therapeutic modalities on serum lipoproteins and on atherosclerotic lesion progression. In the present study the effects of estrogen therapy on serum lipoproteins were investigated after mice were placed on an atherosclerotic diet. The daily oral administration of 20 or 100 μg/kg of 17 α-ethinyl estradiol resulted in a significant, dose-dependent increase in LDL cholesterol over a 20-week regimen. These differences were apparent by 6 weeks and further increases were observed through the 20-week period. Although CETP did result in a reduction in total HDL, estrogen did not have any impact on the amount of CETP activity associated with the HDL particles. The significant increase in LDL cholesterol was associated with increases in the amount of apoB100 and B48 and apoE–containing particles. Hepatic apoB message levels, however, were not different between the experimental groups. Although the extent of atherosclerotic lesions was modest, <0.5% of the aortic surface area in the vehicle group, the high-dose estrogen group, showed an increase in lesion area consistent with the elevation in LDL cholesterol. These lesions, primarily restricted to the aortic root and aortic semilunar valves, were more intensely stained with Oil Red O in the high-dose estrogen group when compared with the vehicle controls.
Minimal Platelet Deposition and Activation in Models of Injured Vessel Wall Ensure Optimal Neutrophil Adhesion Under Flow Conditions
Authors: Zwaginga J. J. , Torres H. I. Gallardo , Lammers J.-W. J. , Sixma J. J. , Koenderman L. , Kuijper P. H. M.
Published: June 2011

Abstract
—Platelets at injured vessel wall form an adhesive surface for leukocyte adhesion. The precise relation between platelet adhesion and activation and leukocyte adhesion, however, is not known. We therefore used various models of injured vessel wall to form different patterns of platelet adhesion. The interaction of polymorphonuclear neutrophils (PMNs) was subsequently studied under flow conditions. In the absence of platelets, not only endothelial cell, smooth muscle cell, and fibroblast matrices but also purified matrix proteins (fibrinogen, collagen, and fibronectin) barely support PMN adhesion. The presence of platelets, however, strongly enhances PMN adhesion. PMN adhesion shows a proportional increase with platelet coverage up to 15%. Although PMNs roll over the scarcely scattered platelets, they speed up again when encountering surfaces without platelets. This “hopping” interaction of PMNs vanishes with platelet coverage >15%. Unobstructed rolling of PMNs is than observed and soon leads to a maximal adhesion of 1000 to 1200 cells/mm
2
. The mean rolling velocity of PMNs continues to decrease with higher platelet coverage. Platelet aggregate formation is an accepted indicator of platelet activation. The presence of platelet aggregates instead of contact or spread platelets, however, does not increase PMN adhesion. Also, additional stimulation of surface-associated platelets by thrombin fails to influence PMN adhesion. Moreover, indomethacin as an inhibitor of platelet activation and aggregation does not change the subsequent PMN interaction. In conclusion, approximately 15% of platelet coverage is sufficient for optimal PMN adhesion. Increasing platelet coverage increases the availability of platelet-associated receptors that lower PMN rolling velocity. Additional activation of adherent platelets makes no difference in the expression of relevant adhesion receptors. Therefore, minimal vascular damage in vivo and only scarce platelet adhesion will already evoke significant colocalization of leukocytes.
Complex Association of Protein C Gene Promoter Polymorphism With Circulating Protein C Levels and Thrombotic Risk
Authors: Aiach Martine , Nicaud Viviane , Alhenc-Gelas Martine , Gandrille Sophie , Arnaud Emmanuel , Amiral Jean , Guize Louis , Fiessinger Jean-Noël , Emmerich Joseph
Published: June 2011

Abstract
—The allele and haplotype frequency of the –1654
C/T
and –1641
A/G
protein C (PC) gene promoter polymorphisms was determined and analyzed according to circulating PC concentrations in 394 healthy subjects aged 20 to 60 years. The
CG
haplotype was associated with a lower PC concentration in both homozygous and heterozygous subjects compared with noncarriers. The
TA
allele had the reverse effect, but only in homozygotes. The distribution of the
CG
and
TA
alleles was significantly different in 242 patients, aged 17 to 60 years, with venous thromboembolism. The
CG
allele increased the risk of thrombosis, with an OR of 1.39 (95% confidence interval (CI), 1.04 to 1.87). The
TA
allele was protective in subjects aged <45 years, with an OR of 0.68 (95% CI, 0.44 to 1.04).
TA
was also significantly associated with older age at the first thrombosis. This study confirms the link between the PC gene promoter and circulating PC levels, and suggests a complex effect on the risk of thrombosis.
Identification and Cloning of a New Gene (2A3-2), Homologous to Human Translational Elongation Factor, Upregulated in a Proliferating Rat Smooth Muscle Cell Line and in Carotid Hyperplasia
Authors: Zibara Kazem , Bourdillon Marie-Claude , Chignier Elza , Covacho Chantal , McGregor John L.
Published: June 2011

Abstract
—Smooth muscle cells (SMCs), before migration and proliferation in the intima of the vessel wall, change from a normal contractile to a pathological proliferating phenotype. The molecular regulatory mechanisms implicated in such phenotypic changes remain poorly understood. In this study, using differential display, we have isolated for the first time a new gene (2A3-2) that is overexpressed in a rapidly proliferating, but not synthetic, rat SMC line. This was further confirmed by northern blot performed on the 2 cell types. Moreover, balloon catheter injury of rat carotids showed, by a virtual northern technique, an upregulation of this new gene in hyperplasia vessels. This new gene (2A3-2, 1.2 kb) was present in skeletal muscle, heart, aorta, lung, liver, kidney, and spleen. In addition, 5′ rapid amplification of cDNA ends (5′ RACE) allowed the cloning and sequencing of this 1.2-kb gene. Comparison of this newly identified gene sequence with data banks showed a strong homology to human and bovine mitochondrial translational elongation factor. The 2A3-2 gene, identified in this study, may play a vital role in the cascade of events implicated in switching SMC phenotype from a quiescent to a proliferate one.
Oxidized Low Density Lipoprotein Suppresses Expression of Inducible Cyclooxygenase in Human Macrophages
Authors: Eligini Sonia , Colli Susanna , Basso Federica , Sironi Luigi , Tremoli Elena
Published: June 2011

Abstract—Atherogenesis involves several aspects of chronic inflammation and wound healing. Indeed, the atheroma is considered a special case of tissue response to injury. Injurious stimuli may include lipoproteins trapped within lesions where protein and lipid moieties have undergone chemical modifications. We have studied the effect of oxidized low density lipoproteins (ox-LDL) on inducible cyclooxygenase (Cox-2) in human monocyte–derived macrophages exposed to bacterial lipopolysaccharide (LPS). Levels of both Cox-2 and constitutive cyclooxygenase (Cox-1) were assessed using Western blot analysis. Prior incubation of macrophages with ox-LDL resulted in a strong inhibition of Cox-2 induced by LPS, without effect on Cox-1. The inhibitory effect was dependent on ox-LDL concentration and its onset was early in time (already detectable 1 hour after macrophage exposure to ox-LDL). Native LDL, and other forms of modified LDL, were without effect. The inhibition was dependent on endocytosis of ox-LDL and could be reproduced using the lipid extract from ox-LDL. Lysophosphatidylcholine, 7β-hydroxycholesterol, and 7-oxocholesterol failed to mimic the inhibition, but oxidized arachidonic acid–containing phospholipids, produced by autoxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, markedly inhibited Cox-2. The observation that ox-LDL downregulates Cox-2 in human macrophages may explain the fact that, within atheromata, the transformation of macrophages into foam cells results in attenuation of the inflammatory response, thus contributing to progression of atherogenesis.
Glucocorticoid Inhibits Oxidized LDL-Induced Macrophage Growth by Suppressing the Expression of Granulocyte/Macrophage Colony-Stimulating Factor
Authors: Sakai Masakazu , Biwa Takeshi , Matsumura Takeshi , Takemura Toru , Matsuda Hirofumi , Anami Yoshichika , Sasahara Takayuki , Kobori Shozo , Shichiri Motoaki
Published: June 2011

Abstract—Glucocorticoid, an anti-inflammatory agent, inhibits the development of atherosclerosis in various experimental animal models. This is partially explained by its ability to inhibit smooth muscle cell migration and proliferation in the intima and to reduce chemotaxis of circulating monocytes and leukocytes into the subendothelial spaces. We have recently demonstrated that oxidized LDL (Ox-LDL) has a mitogenic activity for macrophages in vitro in which Ox-LDL–induced granulocyte/macrophage colony-stimulating factor (GM-CSF) production plays an important role. Proliferation of cellular components is one of the characteristic events in the development and progression of atherosclerotic lesions. In the present study, we investigated the effects of glucocorticoids on Ox-LDL–induced macrophage growth. Dexamethasone, prednisolone, and cortisol inhibited Ox-LDL–induced thymidine incorporation into macrophages by 85%, 70%, and 50%, respectively. Ox-LDL induced a significant production of GM-CSF by macrophages, which was effectively inhibited by dexamethasone, prednisolone, and cortisol by 80%, 65%, and 50%, respectively. Dexamethasone-mediated inhibition of Ox-LDL–induced GM-CSF mRNA expression and macrophage growth was significantly abrogated by RU-486, a glucocorticoid receptor antagonist. Our results suggest that the inhibitory effects of glucocorticoids on macrophage growth may be due to the inhibition of Ox-LDL–induced GM-CSF production through transactivation of the glucocorticoid receptor.
Hyperlipidemia and Atherosclerotic Lesion Development in LDL Receptor–Deficient Mice Fed Defined Semipurified Diets With and Without Cholate
Authors: Lichtman Andrew H. , Clinton Steven K. , Iiyama Kaeko , Connelly Philip W. , Libby Peter , Cybulsky Myron I.
Published: June 2011

Abstract
—Past studies of atherosclerosis in mice have used chow-based diets supplemented with cholesterol, lipid, and sodium cholate to overcome species resistance to lesion formation. Similar diets have been routinely used in studies with LDL receptor–deficient (LDLR
−/−
) mice. The nonphysiological nature and potential toxicity of cholate-containing diets have led to speculation that atherogenesis in these mice may not accurately reflect the human disease process. We have designed a semipurified AIN-76A–based diet that can be fed in powdered, pelleted, or liquid form and manipulated for the precise evaluation of diet–genetic interactions in murine atherosclerosis. LDLR
−/−
mice were randomly assigned among 4 diets (n=6/diet) as follows: 1, control, 10% kcal lipid; 2, high fat (40% kcal), moderate cholesterol (0.5% by weight); 3, high fat, high cholesterol (1.25% by weight); and 4, high fat, high cholesterol, and 0.5% (wt/wt) sodium cholate. Fasting serum cholesterol was increased in all cholesterol-supplemented mice compared with controls after 6 or 12 weeks of feeding (
P
<0.01). The total area of oil red O–stained atherosclerotic lesions was determined from digitally scanned photographs. In contrast to the control group, all mice in cholesterol-supplemented dietary groups 2 to 4 had lesions involving 7.01% to 12.79% area of the thoracic and abdominal aorta at 12 weeks (
P
<0.002, for each group versus control). The distribution pattern of atherosclerotic lesions was highly reproducible and comparable. The histological features of lesions in mice fed cholate-free or cholate-containing diets were similar. This study shows that sodium cholate is not necessary for the formation of atherosclerosis in LDLR
−/−
mice and that precisely defined semipurified diets are a valuable tool for the examination of diet–gene interactions.
Acute Changes in Serum Lipids and Lipoprotein Subclasses in Triathletes as Assessed by Proton Nuclear Magnetic Resonance Spectroscopy
Authors: Yu Harry H. , Ginsburg Geoffrey S. , O’Toole Mary L. , Otvos James D. , Douglas Pamela S. , Rifai Nader
Published: June 2011

Abstract
—Exercise is associated with changes in lipids that may protect against coronary heart disease (CHD). In this study of 28 triathletes, we analyzed acute changes in serum lipid and lipoprotein concentrations after completion of the 1995 World Championship Hawaii Ironman Triathlon. With standard laboratory assays, we demonstrate significant decreases in total cholesterol, VLDL cholesterol, ApoB100, and Lp(a). Total HDL cholesterol increased significantly immediately after the race. With a novel proton NMR spectroscopy assay, we demonstrate that smaller diameter LDL particles, corresponding to small, dense LDL, declined by 62%. Moreover, larger HDL subclasses, whose levels are inversely associated with CHD, increased significantly by 11%. Smaller HDL subclasses, which have been directly associated with CHD in some studies, acutely decreased by 16%. Therefore, exercise not only acutely induces changes in lipoprotein concentrations among the standard species in a manner that favorably affects CHD risk, but also induces favorable changes in specific lipoprotein subclass size distribution that also may alter CHD risk independently of the total lipoprotein serum concentration.
Abetalipoproteinemia Caused by Maternal Isodisomy of Chromosome 4q Containing an Intron 9 Splice Acceptor Mutation in the Microsomal Triglyceride Transfer Protein Gene
Authors: Yang Xiao Ping , Inazu Akihiro , Yagi Kunimasa , Kajinami Kouji , Koizumi Junji , Mabuchi Hiroshi
Published: June 2011

Abstract
—Uniparental disomy (UPD), a rare inheritance of 2 copies of a single chromosome homolog or a region of a chromosome from one parent, can result in various autosomal recessive diseases. Abetalipoproteinemia (ABL) is a rare autosomal recessive deficiency of apoB-containing lipoproteins caused by a microsomal triglyceride transfer protein (MTP) deficiency. In this study, we describe a patient with ABL inherited as a homozygous intron 9 splice acceptor G(−1)-to-A mutation of the transfer protein gene. This mutation alters the splicing of the mRNA, resulting in a 36 amino acids, in-frame deletion of sequence encoded by exon 10. We analyzed chromosome 4, including MTP gene (4q22-24), using short tandem repeat markers. The proband has only his mother’s genes in chromosome 4q spanning a 150-centimorgan region; ie, segmental maternal isodisomy 4q21-35, probably due to mitotic recombination. Nonpaternity between the proband and his father was excluded using 6 polymorphic markers from different chromosomes (paternity probability, 0.999). Maternal isodisomy (maternal UPD 4q) was the basis for homozygosity of the MTP gene mutation in this patient.
Genetic Background Determines the Extent of Atherosclerosis in ApoE-Deficient Mice
Authors: Dansky Hayes M. , Charlton Sherri A. , Sikes John L. , Heath Simon C. , Simantov Ronit , Levin Lawrence F. , Shu Pei , Moore Karen J. , Breslow Jan L. , Smith Jonathan D.
Published: June 2011

Abstract
—Two strains of ApoE-deficient mice were found to have markedly different plasma lipoprotein profiles and susceptibility to atherosclerosis when fed either a low-fat chow or a high-fat Western-type diet. FVB/NJ ApoE-deficient (FVB E0) mice had higher total cholesterol, HDL cholesterol, ApoA1, and ApoA2 levels when compared with C57BL/6J ApoE-deficient (C57 E0) mice. At 16 weeks of age, mean aortic root atherosclerotic lesion area was 7- to 9-fold higher in chow diet–fed C57 E0 mice and 3
.
5
-
fold higher in Western diet–fed C57 E0 mice compared with FVB E0 mice fed similar diets. Lesion area in chow diet–fed first-generation mice from a strain intercross was intermediate in size compared with parental values. The distribution of the lesion area in 150 chow diet–fed second-generation progeny spanned the range of the lesion area in both parental strains. There were no correlations between total cholesterol, non-HDL cholesterol, HDL cholesterol, ApoA1, ApoA2, ApoJ, or anti-cardiolipin antibodies and lesion area in the second-generation progeny. Thus, a genomic approach may succeed in identifying the genes responsible for the variation in atherosclerosis susceptibility in these 2 strains of ApoE-deficient mice, which could not be explained by measured plasma parameters.
Associations of C-Reactive Protein With Measures of Obesity, Insulin Resistance, and Subclinical Atherosclerosis in Healthy, Middle-Aged Women
Authors: Hak A. Elisabeth , Stehouwer Coen D. A. , Bots Michiel L. , Polderman Kees H. , Schalkwijk Casper G. , Westendorp Iris C. D. , Hofman Albert , Witteman Jacqueline C. M.
Published: June 2011

Abstract—Obesity, the insulin resistance syndrome, and atherosclerosis are closely linked and may all be determinants of an increased acute-phase response. In this study, we examined the relationship of C-reactive protein (CRP) with measures of obesity, variables of the insulin resistance syndrome, and intima-media thickness of the common carotid arteries in 186 healthy, middle-aged women selected from the general population. Associations were assessed by regression analysis. CRP was strongly associated with body mass index (BMI) and waist circumference. CRP was also associated with other variables of the insulin resistance syndrome, including blood pressure, insulin, high density lipoprotein cholesterol, triglycerides, apolipoprotein A1 (inversely), plasminogen activator inhibitor-1 antigen, and tissue-type plasminogen activator antigen. Associations between CRP and the variables of the insulin resistance syndrome disappeared after controlling for BMI but remained significant for plasminogen activator inhibitor-1 antigen only. The association of CRP with common carotid artery intima-media thickness was weak and limited to ever-smokers. BMI explained 29.7% of the variance of CRP, whereas common carotid artery intima-media thickness explained only 3.7%. The results of this population-based study indicate that adiposity is strongly associated with CRP in healthy, middle-aged women. In this population, BMI accounted for the relationship between CRP and other variables of the insulin resistance syndrome. Further studies should determine whether losing weight ameliorates the inflammatory state.
Specific Impairment of Human Platelet P2Y
AC
ADP Receptor–Mediated Signaling by the Antiplatelet Drug Clopidogrel
Authors: Geiger J. , Brich J. , Hönig-Liedl P. , Eigenthaler M. , Schanzenbächer P. , Herbert J. M. , Walter U.
Published: June 2011

Abstract
—Clopidogrel is an effective new antiplatelet agent useful for the treatment of ischemic cerebrovascular, cardiac, and peripheral arterial disease. However, the mechanism of clopidogrel action is not well understood, although it is known to inhibit ADP-evoked platelet aggregation. In the current study, the effect of clopidogrel on recently identified human platelet ADP receptors and their signaling pathways was investigated by using platelets from clopidogrel-treated subjects, 6 healthy volunteers (2 females and 4 males) who received 75 mg of clopidogrel daily for 7 days. Blood was taken and various platelet receptor signaling pathways were analyzed before treatment, after 7 days of medication, and 4 weeks after treatment had ceased. Platelet tests included the analysis of aggregation, rapid calcium influx, calcium mobilization from intracellular stores, adenylyl cyclase, and phosphorylation of vasodilator-stimulated phosphoprotein (VASP). The data indicate that clopidogrel does not affect those platelet ADP receptors coupled to cation influx (P2X1 ADP receptors) or calcium mobilization (P2Y1 ADP receptors). In contrast, clopidogrel treatment specifically impairs the ADP receptor coupled to G
i
/adenylyl cyclase (P2Y
AC
ADP receptors). Clopidogrel abolishes the inhibitory P2Y
AC
receptor–mediated ADP effects on prostaglandin E
1
–stimulated, cAMP-dependent phosphorylation of VASP without affecting epinephrine, thrombin, and thromboxane signaling. VASP phosphorylation is known to be closely correlated with the inhibition of platelet and fibrinogen receptor (glycoprotein IIb/IIIa) activation. Therefore, inhibition of the platelet P2Y
AC
ADP receptor and its intracellular signaling, including decreased VASP phosphorylation, is suggested as a molecular mechanism of clopidogrel action.
Angiostatin Binds to Smooth Muscle Cells in the Coronary Artery and Inhibits Smooth Muscle Cell Proliferation and Migration In Vitro
Authors: Walter Jennifer J. , Sane David C.
Published: June 2011

Abstract
—Angiostatin is an inhibitor of angiogenesis that is known to reduce endothelial cell proliferation and consequently prevent the progression of tumor metastases. However, the modest effect of angiostatin on endothelial cell proliferation raises the possibility that angiostatin might exert its effects on other cells. To determine the cellular distribution of angiostatin binding in tissues with neovasculature (atherosclerotic coronary arteries), we developed a fusion protein consisting of placental alkaline phosphatase and the first 3 kringles of plasminogen. Angiostatin binding colocalized with smooth muscle cells and could be inhibited by a 50-fold molar excess of plasminogen and 10 mmol/L ε-amino-
n
-caproic acid. The fusion protein also bound to smooth muscle cells in culture. Angiostatin inhibited hepatocyte growth factor–induced proliferation and migration of smooth muscle cells, suggesting that they are a target for the antiangiogenic effect of angiostatin.
Adenovirus-Mediated Overexpression of c-Jun and c-Fos Induces Intercellular Adhesion Molecule-1 and Monocyte Chemoattractant Protein-1 in Human Endothelial Cells
Authors: Wang Nanping , Verna Lynne , Hardy Stephen , Forsayeth John , Zhu Yi , Stemerman Michael B.
Published: June 2011

Abstract—As distal targets and mediators of signal transduction pathways, activator protein-1 (AP-1), c-Jun, and c-Fos are among the primary regulators of genes involved in cell function, proliferation, and differentiation. By using adenovirus-mediated gene transfer, we show that overexpression of AP-1 proteins directly causes coinduction of gene expression of an adhesion molecule, intercellular adhesion molecule-1 (ICAM-1), and a chemokine, monocyte chemoattractant protein-1 (MCP-1), in human vascular endothelial cells (ECs). The AP-1–induced gene expression occurs through a mechanism independent of nuclear factor-κB. Because the induced expression of ICAM-1 and MCP-1 in ECs has been implicated in endothelial activation and a number of important vascular disorders, it is suggested that AP-1 activation may play an important role in the pathogeneses of inflammation, angiogenesis, and atherogenesis.
Acute effects of transluminal angioplasty in three experimental models of atherosclerosis.
Authors: Faxon D P , Weber V J , Haudenschild C , Gottsman S B , McGovern W A , Ryan T J
Published: June 2011

Transluminal angioplasty has shown promise as a nonoperative treatment of atherosclerotic obstruction. Despite its increasing clinical use and potential importance, little is known of its mechanism and acute effects. To evaluate transluminal angioplasty, three rabbit models of experimental atherosclerosis were developed: Group 1 (n = 20) = high cholesterol diet plus balloon de-endothelialization; Group 2A (n = 12) = high cholesterol diet plus an indwelling catheter; Group 2B (n = 10) = normal diet plus an indwelling catheter. After 6 weeks or 8 weeks, distinct angiographic and pathological lesions in the iliac artery were evident in all groups. Group 1 showed predominant foam cell lesions, while Group 2 showed eccentric mixed fibrous and foam cell or only fibrous lesions. Significant angiographic stenosis was present in 78% of the animals. Angioplasty of the highest grade iliac stenosis resulted in at least a 20% reduction in luminal diameter narrowing in 26 of 37 animals (70%). Histopathological examination 1 day following angioplasty in 17 animals showed two patterns. In Group 1 animals, neointimal fracture and dissection were evident, while in Group 2 animals thinning and stretching of the nonatherosclerotic portion of the vessel walls could be demonstrated. This study demonstrates that the New Zealand rabbit can be used to produce a spectrum of morphologically distinct atherosclerotic lesions that lend themselves to the study of transluminal angioplasty. The immediate consequences of angioplasty, which appear to depend upon the underlying histopathology and widening of the narrowed lumen, are frequently concurrent with intimal fracture, dissection, or thinning of the nonatherosclerotic portion of the vessel wall.
Familial associations of lipids and lipoproteins in families of hypercholesterolemic probands.
Authors: Morrison J A , Khoury P , Laskarzewski P M , Mellies M J , Heinemeyer R , Glueck C J
Published: June 2011

We used the Princeton School Family Study hypercholesterolemic recall group to assess whether, and to what degree, the identification of hypercholesterolemic subjects could be improved through the phenomenon of familial lipid and lipoprotein aggregation. A second aim was to assess whether within-family lipid and lipoprotein correlations outlasted the period of shared family environment. Approximately twice as many (as expected) siblings and offspring of hypercholesterolemic probands had plasma total and low density lipoprotein cholesterol levels greater than the 90th and 75th percentiles respectively, emphasizing how identification of hypercholesterolemic subjects can be facilitated by use of the phenomenon of familial aggregation of plasma total and low density lipoprotein cholesterol. After exclusion of the hypercholesterolemic probands from calculations of within-family correlations, and use of natural log transformations for the probands' first-degree relatives' lipids as required, most father/pediatric offspring and mother/pediatric offspring correlations for lipids and lipoprotein cholesterols were significant, while most parent/adult offspring correlations were not significant. All pediatric sibling correlations for lipids and lipoprotein cholesterols were significant; most adult sibling correlations were not significant. The loss of significance and consistency in sibling and parent/offspring lipid and lipoprotein correlations in adults who no longer shared a common household environment points to environmental influences on total, high, and low density lipoprotein cholesterol in kindreds with a hypercholesterolemic proband.
Radioimmunoassay of apolipoprotein a-ii.
Authors: Musliner T A , Garner P A , Henderson L O , Herbert P N
Published: June 2011

A double antibody radioimmunoassay was developed for apolipoprotein A-II (apo A-II), one of the two major apoproteins of human high density lipoproteins (HDL). Apo A-II contains two identical polypeptide chains linked by a disulfide bond. A specific antiserum was raised in sheep. Tracer apo A-II was radiolabeled with 125I by the Bolton-Hunter technique. Reduction and carboxymethylation of apo A-II approximately doubled its immunoreactivity. Since normal sera were found to contain small amounts of monomeric apo A-II, this represented one potential source of error in the radioimmunoassay. Inclusion of 0.1 M sodium cholate in the assay system, however, led to identical immunoreactivity of dimeric apo A-II and the reduced and carboxymethylated protein. Radioimmunoassay using sheep anti-apo A-II detected 75% to 85% of the apo A-II contained in serum or HDL. Masked antigenic sites could be exposed by organic solvent extraction or, more simply, by dilution of serum samples in the buffer containing 0.1 M sodium cholate. Serum levels of apo A-II were measured in a population of consecutively and prospectively selected free-living subjects between 30 to 69 years of age. Levels were significantly (p less than 0.005) higher in females (n = 201; 42.0 +/- 10.3 mg/dl) than in males (n = 189; 39.0 +/- 8.4 mg/dl). Serum apo A-II levels correlated significantly with HDL-cholesterol levels but less strongly than apo A-I, the other major HDL apoprotein.
Atherosclerosis and oral contraceptive use. Serum from oral contraceptive users stimulates growth of arterial smooth muscle cells.
Authors: Bagdade J D , Subbaiah P V
Published: June 2011

Pooled serum from women taking a combined estrogen-progestin oral contraceptive preparation caused significantly greater cell proliferation and incorporation of 3H-thymidine into DNA in both human arterial smooth muscle cells and dermal fibroblasts in tissue culture than did serum from controls. A portion of this mitogenic effect appears to be related to the presence of a factor(s) that is heat stable, nondialyzable, and contained in the lipoprotein-deficient serum fraction. In vitro addition of varying concentrations of mestranol and norethindrone, the two constituents of the oral contraceptive preparation taken by participants in the study, to control serum did not enhance its mitogenicity, suggesting that the effect observed with intact serum was due either to a metabolite of these compounds or to the production of other growth-promoting substances during oral contraceptive treatment. Since smooth muscle cell proliferation is an integral feature of all atherosclerotic lesions, these findings provide some insights applicable to understanding the pathogenesis of vascular disease associated with oral contraceptive use.
Inhibition of endothelial cell regrowth. Cessation of aortic endothelial cell replication after balloon catheter denudation.
Authors: Reidy M A , Standaert D , Schwartz S M
Published: June 2011

Aortas of male rabbits (2.0 to 2.5 kg body weight) were denuded of endothelium with a 4F balloon catheter and killed 7, 14, 60, 90, and 180 days later. Aortic endothelial cells regrowth was determined using Evans blue dye and scanning electron microscopy. Early endothelial outgrowth was rapid, but by 14 days the regrowth slowed markedly so that no further increase of endothelial outgrowth was detected at other time periods. Another group of animals received 3H-thymidine 1 hour before death and were killed 4, 14, and 42 days later. The endothelial cells replication in the aortas of these animals was measured from Häutchen preparations. Endothelial cells replication was observed 4 days after balloon injury but was markedly reduced by 14 and 42 days. Intimal smooth muscle cell replication, however, was observed at both these later times. These result demonstrate that in vivo endothelial cells replication stops long before the aorta is repopulated and suggest that some mechanism other than contact between endothelial cells can prevent endothelial cell replication.
Proteoglycan distribution in areas of differing permeability to Evans blue dye in the aortas of young pigs. An ultrastructural study.
Authors: Richardson M , Gerrity R G , Alavi M Z , Moore S
Published: June 2011

We studied proteoglycan distribution in areas of spontaneously occurring high and low permeability by TEM examination of ruthenium red-stained sections of the aortic arch of normolipemic and hyperlipemic pigs. We noted granules of two sizes: those smaller than 20 nm contained heparan sulphate, and those from 20 to 50 nm in size contained chondroitin or dermatan sulphate. In the aortas of pigs fed a normal diet, there were significantly more granules of both types in low permeability areas than in areas permeable to Evans blue dye. This is consistent with the theory that glycosaminoglycan provides a component for the control of aortic permeability. In the aortas of pigs fed cholesterol, there was an accumulation of lipid-filled monocytes in areas of high permeability and an increase in proteoglycan granule concentration, suggesting an increase in glycosaminoglycan concentration, which may be the precursor to extracellular lipid deposition.
Oligoclonal T Cell Expansions in Atherosclerotic Lesions of Apolipoprotein E–Deficient Mice
Authors: Paulsson Gabrielle , Zhou Xinghua , Törnquist Elisabeth , Hansson Göran K.
Published: June 2011

Abstract
—T cells are present in atherosclerotic lesions at all stages of development. They exhibit activation markers and are particularly prominent at sites of plaque rupture. This suggests that T-cell–mediated immune responses are involved in the pathogenesis of atherosclerosis. Antigen-specific T cells reactive with oxidized lipoproteins and heat shock proteins have been isolated from plaques, indicating that local activation and clonal expansion might occur. To analyze different stages of atherosclerosis, we have used a murine model. Targeted deletion of the apolipoprotein E gene results in severe hypercholesterolemia and spontaneous atherosclerosis, with lesions containing large numbers of T cells and macrophages. We have analyzed mRNA for T-cell antigen receptors (TCRs) from aortic fatty streaks, early fibrofatty plaques, and advanced fibrofatty plaques of such mice. Polymerase chain reaction amplification of complementarity-determining region 3 (CDR3 region) of TCRs was followed by spectratyping of fragment lengths. This analysis detected all types of variable (V) segments with a gaussian distribution of CDR3 in lymph nodes. In contrast, a restricted heterogeneity was found in atherosclerotic lesions, with expansion of a limited set of Vβ and Vα segments and a monotypic or oligotypic CDR3 spectrum in each lesion. Vβ6 was expressed in all lesions; Vβ5.2, Vβ16, Vα34s, and Vα9, in the majority of lesions; and Vβ6, Vβ5.2, and Vα34S, in lesions at all 3 stages of development. The strongly skewed pattern of the CDR3 region in the TCR is indicative of oligoclonal expansions of T cells and suggests the occurrence of antigen-driven T-cell proliferation in atherosclerosis.