bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Density Lipoprotein Receptor of Macrophages Facilitates Atherosclerotic Lesion Formation in C57Bl/6 Mice
Authors: Herijgers Nicole , Van Eck Miranda , Groot Pieter H. E. , Hoogerbrugge Peter M. , Van Berkel Theo J. C.
Published: June 2011

Abstract
—Macrophage-derived foam cells play an important role in the initiation and progression of atherosclerosis. To examine the role of the macrophage low density lipoprotein receptor (LDLr) in atherosclerotic lesion formation, bone marrow from LDLr knockout [LDLr(−/−)] mice was transplanted into irradiated wild-type C57Bl/6 [LDLr(+/+)] mice. After 3 months on an atherogenic diet, C57Bl/6 mice, reconstituted with LDLr(−/−) bone marrow, showed a mean lesion area of 34.7×10
3
±22.4x10
3
μm
2
compared with 100.8×10
3
±33.0×10
3
μm
2
(
P
<0.001) in control C57Bl/6 mice that were transplanted with LDLr(+/+) bone marrow. There were no significant differences in total serum cholesterol, triglyceride levels, and lipoprotein profiles between the 2 groups. Histochemical analysis of macrophage LDLr expression in the atherosclerotic lesions indicated that C57Bl/6 mice, reconstituted with LDLr(+/+) bone marrow, showed extensive staining of the foam cells in the atherosclerotic lesions, whereas mice reconstituted with LDLr(−/−) bone marrow showed only a few LDLr-positive foam cells. In vitro, peritoneal macrophages isolated from wild-type C57Bl/6 mice were, respectively, 4.7- and 10.7-fold more effective in cell association and degradation of atherogenic
125
I-β-very low density lipoprotein than were LDLr(−/−) peritoneal macrophages, establishing that the LDLr on macrophages is important for the interaction of macrophages with β-very low density lipoprotein. It is concluded that the LDLr on macrophages can facilitate the development of atherosclerosis, possibly by mediating the uptake of atherogenic lipoproteins.
ApoE Polymorphism and Fish Oil Supplementation in Subjects With an Atherogenic Lipoprotein Phenotype
Authors: Minihane Anne M. , Khan Syrah , Leigh-Firbank Elizabeth C. , Talmud Philippa , Wright John W. , Murphy Margaret C. , Griffin Bruce A. , Williams Christine M.
Published: June 2011

Abstract
—The study assessed the efficacy of fish oil supplementation in counteracting the classic dyslipidemia of the atherogenic lipoprotein phenotype (ALP). In addition, the impact of the common apolipoprotein E (apoE) polymorphism on the fasting and postprandial lipid profile and on responsiveness to the dietary intervention was established. Fifty-five ALP males (aged 34 to 69 years, body mass index 22 to 35 kg/m
2
, triglyceride [TG] levels 1.5 to 4.0 mmol/L, high density lipoprotein cholesterol [HDL-C] <1.1 mmol/l, and percent low density lipoprotein [LDL]-3 >40% total LDL) completed a randomized placebo-controlled crossover trial of fish oil (3.0 g eicosapentaenoic acid/docosahexaenoic acid per day) and placebo (olive oil) capsules with the 6-week treatment arms separated by a 12-week washout period. In addition to fasting blood samples, at the end of each intervention arm, a postprandial assessment of lipid metabolism was carried out. Fish oil supplementation resulted in a reduction in fasting TG level of 35% (
P
<0.001), in postprandial TG response of 26% (TG area under the curve,
P
<0.001), and in percent LDL-3 of 26% (
P
<0.05). However, no change in HDL-C levels was evident (
P
=0.752). ANCOVA showed that baseline HDL-C levels were significantly lower in apoE4 carriers (
P
=0.035). The apoE genotype also had a striking impact on lipid responses to fish oil intervention. Individuals with an apoE2 allele displayed a marked reduction in postprandial incremental TG response (TG incremental area under the curve,
P
=0.023) and a trend toward an increase in lipoprotein lipase activity relative to non-E2 carriers. In apoE4 individuals, a significant increase in total cholesterol and a trend toward a reduction in HDL-C relative to the common homozygous E3/E3 profile was evident. Our data demonstrate the efficacy of fish oil fatty acids in counteracting the proatherogenic lipid profile of the ALP but also that the apoE genotype influences responsiveness to this dietary treatment.
Associations of Coronary Heart Disease Risk Factors With the Intermediate Lesion of Atherosclerosis in Youth
Authors: McGill Henry C. , McMahan C. Alex , Zieske Arthur W. , Sloop Gregory D. , Walcott Jamie V. , Troxclair Dana A. , Malcom Gray T. , Tracy Richard E. , Oalmann Margaret C. , Strong Jack P. , Youth Research Group for the Pathobiological Determinants of Atherosclerosis in
Published: June 2011

Abstract
—The raised fatty streak (fatty plaque) is the gross term for the lesion intermediate between the juvenile (flat) fatty streak and the raised lesion of atherosclerosis. We measured the percentage of intimal surface involved with flat fatty streaks, raised fatty streaks, and raised lesions in the aortas and right coronary arteries of 2876 autopsied persons aged 15 through 34 years who died of external causes. Raised fatty streaks were present in the abdominal aortas of ≈20% of 15- to 19-year-old subjects, and this percentage increased to ≈40% for 30- to 34-year-old subjects. Raised fatty streaks were present in the right coronary arteries of ≈10% of 15- to 19-year-old subjects, and this percentage increased to ≈30% for 30- to 34-year-old subjects. The percent intimal surface involved with raised fatty streaks increased with age in both arteries and was associated with high non–high density lipoprotein (HDL) and low HDL cholesterol concentrations in the abdominal aorta and right coronary artery, with hypertension in the abdominal aorta, with obesity in the right coronary artery of men, and with impaired glucose tolerance in the right coronary artery. Associations of risk factors with raised fatty streaks became evident in subjects in their late teens, whereas associations of risk factors with raised lesions became evident in subjects aged >25 years. These results are consistent with the putative transitional role of raised fatty streaks and show that coronary heart disease risk factors accelerate atherogenesis in the second decade of life. Thus, long-range prevention of atherosclerosis should begin in childhood or adolescence.
Plasma Levels of Tissue Plasminogen Activator/Plasminogen Activator Inhibitor-1 Complex and von Willebrand Factor Are Significant Risk Markers for Recurrent Myocardial Infarction in the Stockholm Heart Epidemiology Program (SHEEP) Study
Authors: Wiman Björn , Andersson Tomas , Hallqvist Johan , Reuterwall Christina , Ahlbom Anders , deFaire Ulf
Published: June 2011

Abstract
—An impaired fibrinolytic function due to elevated plasma levels of plasminogen activator inhibitor (PAI)-1 activity or tissue plasminogen activator (tPA) antigen is correlated with the development of myocardial infarction (MI) in patients with manifest coronary heart disease. Recently, methods for determining the specific tPA/inhibitor complexes constituting tPA antigen in plasma have become available. In the Stockholm Heart Epidemiology Program (SHEEP) study, 86 of 1212 MI patients, subjected to blood sampling in a metabolically stable period, suffered reinfarction before the end of 1996. These individuals have been compared with an approximately equal number of matched MI patients without recurrence and a group of matched healthy control subjects regarding the plasma concentrations of some hemostatic factors. The hemostatic compounds studied (fibrinogen, von Willebrand factor, tPA antigen, PAI-1, and the tPA/PAI-1 complex) were typically higher in the groups (men and women) with recurrence of MI compared with those without. The plasma concentrations were also typically higher in the pooled groups of patients compared with the groups of healthy control subjects. The largest between-group differences were found for the plasma tPA/PAI-1 complex. The crude odds ratio for reinfarction associated with higher concentration (≥75th percentile among the control subjects) of tPA/PAI-1 was 1.8 (95% CI 1.1 to 3.1); the corresponding crude odds ratio for von Willebrand factor was 2.3 (1.3 to 4.0). The tPA/PAI-1 complex correlated strongly with PAI-1 and tPA antigen in all groups and with serum triglycerides and body mass index in all groups except for women with reinfarction. An increased plasma level of tPA/PAI-1 complex is a novel risk marker for recurrent MI in men and women. Most likely, increased plasma levels of tPA/PAI-1 complex reflect impaired fibrinolysis, because the correlation with PAI-1 is strong. Further support is obtained indicating that the plasma concentration of von Willebrand factor is also an important risk marker for recurrent MI.
Site-Specific Antiatherogenic Effect of Probucol in Apolipoprotein E–Deficient Mice
Authors: Witting Paul K. , Pettersson Knut , Letters Jacinta , Stocker Roland
Published: June 2011

Abstract
—The lipid-lowering antioxidant probucol can inhibit atherosclerosis in animals and restenosis in humans. However, probucol has been shown to promote atherosclerosis in the aortic root of apolipoprotein E–deficient (apoE−/−) mice. In the current study, we examined the effects of probucol on both lesion formation at 4 sites along the aorta and lipoprotein oxidation in the plasma and aortas of apoE−/− mice receiving a diet containing 21.2% (wt/wt) fat and 0.15% (wt/wt) cholesterol without or with 1% (wt/wt) probucol. After 6 months, controls had developed lesions at all sites investigated. Lesion development was strongly (
P
=0.0001) affected by probucol, but this effect was not uniform: lesion size was increased in the aortic root but significantly decreased in the arch, the descending thoracic aorta, and proximal abdominal aorta. Plasma and aortas of probucol-treated mice contained high concentrations of probucol and its metabolites (bisphenol and diphenoquinone); increased vitamin C; markedly decreased very low density lipoprotein (but not low density lipoprotein and high density lipoprotein); and decreased cholesterol, cholesteryl esters, triglycerides, vitamin E, and oxidized lipids compared with controls. Interestingly, probucol treatment did not decrease the proportion of aortic lipids that were oxidized. Plasma vitamin C and bisphenol, but not probucol, protected plasma lipids from ex vivo oxidation by peroxyl radicals. These results show that as in other species, probucol can inhibit lesion formation in most parts of the aorta of apoE−/− mice. This effect may involve lipid oxidation–independent mechanisms localized within the vessel wall as well as lipid lowering.
Acute Elevations of Plasma Asymmetric Dimethylarginine and Impaired Endothelial Function in Response to a High-Fat Meal in Patients With Type 2 Diabetes
Authors: Fard Ali , Tuck Catherine H. , Donis Joshua A. , Sciacca Robert , Di Tullio Marco R. , Wu Henry D. , Bryant Todd A. , Chen Niem-Tzu , Torres-Tamayo Margarita , Ramasamy Ravichandran , Berglund Lars , Ginsberg Henry N. , Homma Shunichi , Cannon Paul J.
Published: June 2011

Abstract
—Asymmetric dimethylarginine (ADMA), a compound detectable in human plasma, is an endogenous inhibitor of NO synthase. Endothelial dysfunction is an early event in atherogenesis, and large-vessel atherosclerosis is a major cause of morbidity and mortality in patients with type 2 diabetes mellitus. Fifty patients with type 2 diabetes mellitus were studied at baseline and 5 hours after ingestion of a high-fat meal. Plasma ADMA measured by using high-performance liquid chromatography increased from 1.04±0.99 to 2.51±2.27 μmol/L (
P
<0.0005). Brachial arterial vasodilation after reactive hyperemia, a NO-dependent function, measured by high-resolution ultrasound, decreased from 6.9±3.9% at baseline to 1.3±4.5% (
P
<0.0001). These changes occurred in association with increased plasma levels of triglycerides and very low density lipoprotein triglycerides, with reduced low density lipoprotein cholesterol and high density lipoprotein cholesterol, and with no changes in total cholesterol. The increase in plasma ADMA in response to a high-fat meal was significantly and inversely related to the decrease in percent vasodilation. In 10 of the subjects studied with a similar protocol on another day, no significant changes in the brachial artery flow responses or in plasma ADMA were observed 5 hours after ingestion of a nonfat isocaloric meal. The data suggest that ADMA may contribute to abnormal blood flow responses and to atherogenesis in type 2 diabetics.
Vasodilator-Stimulated Phosphoprotein Is Involved in Stress-Fiber and Membrane Ruffle Formation in Endothelial Cells
Authors: Price Caroline J. , Brindle Nicholas P. J.
Published: June 2011

Abstract
—Vasodilator-stimulated phosphoprotein (VASP) is highly expressed in vascular endothelial cells, where it has been implicated in cellular reorganization during angiogenesis, as well as in endothelial retraction and changes in vessel permeability. However, the cellular functions of VASP are not known. In this study, we have expressed wild-type and mutant forms of VASP in endothelial cells to determine in what aspects of cytoskeletal behavior this protein participates. Expression of wild-type VASP induces marked membrane ruffling and formation of prominent stress fibers in bovine aortic endothelial cells. Deletion of the proline-rich domain of VASP abolishes its ability to bind profilin but does not affect ruffling or stress fiber formation. Further deletions reveal a sequence within the carboxy-terminal domain that is responsible for in vivo bundle formation. Ruffling occurs only on the expression of forms of VASP that possess bundling activity and the capacity to bind zyxin/vinculin-derived peptide. The ability of distinct subdomains within VASP to bind adhesion proteins and induce F-actin bundling in vivo suggests that this protein could function in the aggregation and tethering of actin filaments during the formation of endothelial cell–substrate and cell-cell contacts. These data provide a mechanism whereby VASP can influence endothelial migration and organization during capillary formation and modulate vascular permeability via effects on endothelial cell contractility.
Overexpression of 15-Lipoxygenase in Vascular Endothelium Accelerates Early Atherosclerosis in LDL Receptor–Deficient Mice
Authors: Harats Dror , Shaish Aviv , George Jacob , Mulkins Mary , Kurihara Hiroki , Levkovitz Hana , Sigal Elliott
Published: June 2011

Abstract
—To study the possible role of the human lipid-oxidizing enzyme 15-lipoxygenase (15-LO) in atherosclerosis, we overexpressed it specifically in the vascular wall of C57B6/SJL mice by using the murine preproendothelin-1 promoter. The mice overexpressing 15-LO were crossbred with low density lipoprotein (LDL) receptor–deficient mice to investigate atherogenesis. High levels of 15-LO were expressed in the atherosclerotic lesion in the double-transgenic mice as assessed by immunohistochemistry. The double-transgenic, 15-LO–overexpressing, LDL receptor–deficient mice (LDLR
−
/−
/15LO) developed significantly larger atherosclerotic lesions at the aortic sinus compared with lesions in the LDL receptor–deficient (LDLR
−
/−
) mice after 3 and 6 weeks (107 000 versus 28 000 μm
2
[
P
<0.001] and 121 000 versus 87 000 μm
2
[
P
<0.05], respectively) of an atherogenic diet. LDL from the LDLR
−
/−
/15LO mice was more susceptible to oxidation than was the LDL from the control LDLR
−
/−
mice, as shown by a shorter lag period for copper-induced conjugated diene formation. On the other hand, no differences were found in the levels of serum anti–oxidized LDL antibodies between the study groups. There were also no differences with respect to the density of macrophages and T lymphocytes infiltrating the lesions in both experimental groups. Taken together, these results support the hypothesis that 15-LO overexpression in the vessel wall is associated with enhanced atherogenesis.
Vaccine-Induced Antibodies Inhibit CETP Activity In Vivo and Reduce Aortic Lesions in a Rabbit Model of Atherosclerosis
Authors: Rittershaus Charles W. , Miller David P. , Thomas Lawrence J. , Picard Michele D. , Honan Christopher M. , Emmett Constance D. , Pettey Carolyn L. , Adari Hedy , Hammond Russell A. , Beattie David T. , Callow Allan D. , Marsh Henry C. , Ryan Una S.
Published: June 2011

Abstract
—Using a vaccine approach, we immunized New Zealand White rabbits with a peptide containing a region of cholesteryl ester transfer protein (CETP) known to be required for neutral lipid transfer function. These rabbits had significantly reduced plasma CETP activity and an altered lipoprotein profile. In a cholesterol-fed rabbit model of atherosclerosis, the fraction of plasma cholesterol in HDL was 42% higher and the fraction of plasma cholesterol in LDL was 24% lower in the CETP-vaccinated group than in the control-vaccinated group. Moreover, the percentage of the aorta surface exhibiting atherosclerotic lesion was 39.6% smaller in the CETP-vaccinated rabbits than in controls. The data reported here demonstrate that CETP activity can be reduced in vivo by vaccination with a peptide derived from CETP and support the concept that inhibition of CETP activity in vivo can be antiatherogenic. In addition, these studies suggest that vaccination against a self-antigen is a viable therapeutic strategy for disease management.
Association of Fibrinogen With Quantity of Coronary Artery Calcification Measured by Electron Beam Computed Tomography
Authors: Bielak Lawrence F. , Klee George G. , Sheedy Patrick F. , Turner Stephen T. , Schwartz Robert S. , Peyser Patricia A.
Published: June 2011

Abstract
—Increased plasma fibrinogen concentration is an independent risk factor for cardiovascular disease. Fibrinogen is the main coagulation protein in plasma, a determinant of blood viscosity, and can act as a cofactor for platelet aggregation. In this study of middle-aged men and women, we examined the association between plasma fibrinogen concentration and coronary artery calcification (CAC), a marker of preclinical coronary atherosclerosis. Two hundred twenty-eight participants were selected from the community-based Epidemiology of Coronary Artery Calcification Study, in which CAC was measured noninvasively by electron beam computed tomography. One hundred fourteen participants (57 men) were selected because they had high quantities of CAC; the remaining 114 participants (57 men) were selected because they had no detectable CAC. Logistic regression models were used to investigate the association between plasma fibrinogen concentration and high quantity of CAC. In men, an increase of 1 standard deviation in fibrinogen concentration was associated with a statistically significant odds ratio of 1.6 (95% CI 1.1 to 2.5) for a high quantity of CAC. In women, the corresponding odds ratio was 2.5 (95% CI 1.6 to 4.1). Inferences from sex-specific bivariate logistic models for odds ratios adjusted individually for each coronary risk factor and C-reactive protein were similar to those from the univariate models. In women, there was also a significant interaction between fibrinogen concentration and age. According to the models, younger women with high plasma fibrinogen were more likely to have high quantities of CAC than were younger women with low plasma fibrinogen. The strength of this association was diminished in older women.
Role of Macrophage-Derived Lipoprotein Lipase in Lipoprotein Metabolism and Atherosclerosis
Authors: Van Eck Miranda , Zimmermann Robert , Groot Pieter H. E. , Zechner Rudolf , Van Berkel Theo J. C.
Published: June 2011

Abstract
—Lipoprotein lipase (LPL) synthesis by macrophages is upregulated in early atherogenesis, implicating the possible involvement of LPL in plaque formation. However, it is still unclear whether macrophage-derived LPL displays a proatherosclerotic or an antiatherosclerotic role in atherosclerotic lesion development. In this study, the role of macrophage-derived LPL on lipid metabolism and atherosclerosis was assessed in vivo by transplantation of LPL-deficient (LPL−/−) and wild-type (LPL+/+) bone marrow into C57BL/6 mice. Eight weeks after bone marrow transplantation (BMT), serum cholesterol levels in LPL−/−→C57BL/6 mice were reduced by 8% compared with those in LPL+/+→C57BL/6 mice (
P
<0.05, n=16), whereas triglycerides were increased by 33% (
P
<0.05, n=16). Feeding the mice a high-cholesterol diet increased serum cholesterol levels in LPL−/−→C57BL/6 and LPL+/+→C57BL/6 mice 5-fold and 9-fold, respectively, resulting in a difference of ≈50% (
P
<0.01) after 3 months on the diet. No effects on triglyceride levels were observed under these conditions. Furthermore, serum apolipoprotein E levels were reduced by 50% in the LPL−/−→C57BL/6 mice compared with controls under both dietary conditions. After 3 months on a high-cholesterol diet, the atherosclerotic lesion area in LPL−/−→C57BL/6 mice was reduced by 52% compared with controls. It can be concluded that macrophage-derived LPL plays a significant role in the regulation of serum cholesterol, apolipoprotein E, and atherogenesis, suggesting that specific blockade of macrophage LPL production may be beneficial for decreasing atherosclerotic lesion development.
High Density Lipoproteins and Arteriosclerosis
Authors: von Eckardstein Arnold , Nofer Jerzy-Roch , Assmann Gerd
Published: June 2011

Abstract
—High density lipoprotein (HDL) cholesterol is an important risk factor for coronary heart disease, and HDL exerts various potentially antiatherogenic properties, including the mediation of reverse transport of cholesterol from cells of the arterial wall to the liver and steroidogenic organs. Enhancement of cholesterol efflux and of reverse cholesterol transport (RCT) is considered an important target for antiatherosclerotic drug therapy. Levels and composition of HDL subclasses in plasma are regulated by many factors, including apolipoproteins, lipolytic enzymes, lipid transfer proteins, receptors, and cellular transporters. In vitro experiments as well as genetic family and population studies and investigation of transgenic animal models have revealed that HDL cholesterol plasma levels do not necessarily reflect the efficacy and antiatherogenicity of RCT. Instead, the concentration of HDL subclasses, the mobilization of cellular lipids for efflux, and the kinetics of HDL metabolism are important determinants of RCT and the risk of atherosclerosis.
HSP47 Expression by Smooth Muscle Cells Is Increased During Arterial Development and Lesion Formation and Is Inhibited by Fibrillar Collagen
Authors: Rocnik Edward , Saward Laura , Pickering J. Geoffrey
Published: June 2011

Abstract
—HSP47 is a heat-shock protein that interacts with intracellular procollagen. It has been found in fibrous atherosclerotic plaque, but its involvement in acute vascular restructuring is unknown. We analyzed the expression of HSP47 and its regulation in the developing rat aorta and after balloon injury to the adult rat carotid artery. HSP47 was strongly expressed in each layer of the maturing fetal aorta (embryonic day 17 to birth). Expression declined during the first 4 postnatal days but persisted at low abundance into adulthood. HSP47 expression was substantially upregulated in the injured carotid artery, with intense immunostaining in neointimal smooth muscle cells (SMCs). HSP47 expression in SMCs was correlated with the emergence of a less mature phenotype and with expression of type I procollagen. Interestingly, a precipitous decline in HSP47 expression was evident during aortic development and after carotid artery injury, in association with the appearance of collagen fibrils in the local extracellular matrix. Furthermore, type I collagen fibrils, but not collagen monomers, inhibited expression of HSP47 by SMCs. These findings indicate that upregulation of HSP47 is a feature of vascular restructuring, including acute neointimal formation, and that the constituents of the extracellular matrix regulate the duration of expression. This feedback control may be important for self-termination of vascular development and lesion growth.
Estrogen and Angiogenesis
Authors: Losordo Douglas W. , Isner Jeffrey M.
Published: June 2011

Abstract
—Multiple lines of evidence suggest that estrogen directly modulates angiogenesis via effects on endothelial cells. Under physiological conditions, angiogenesis is routinely observed in the uterus in association with fluctuations in the levels of circulating estradiol and other sex steroids. In pathological circumstances, such as breast cancer, a clear association between estrogen, estrogen receptor expression by endothelial cells, angiogenic activity, and/or tumor invasiveness has been made. Studies performed in our laboratory have revealed that estradiol accelerates functional endothelial recovery after arterial injury. Despite these consistent observations, the mechanisms by which estrogen regulates angiogenesis under physiological and pathological circumstances have not been defined.
ACE Inhibitor and AT
1
Antagonist Blockade of Deformation-Induced Gene Expression in the Rabbit Jugular Vein Through B
2
Receptor Activation
Authors: Lauth Manfred , Cattaruzza Marco , Hecker Markus
Published: June 2011

Abstract
—Deformation-induced endothelin-1 synthesis in endothelial cells may contribute to the intimal hyperplasia of venous bypass grafts. ACE inhibitors and angiotensin II type 1 (AT
1
) receptor antagonists are capable of reducing vein graft disease. Therefore, the effects of these drugs on endothelial preproendothelin-1 (ppET-1) and smooth muscle endothelin B receptor (ET
B
-R) expression were investigated in isolated perfused segments of the rabbit jugular vein. Pretreatment with ramiprilat (0.3 μmol/L) or irbesartan (0.01 to 1 μmol/L) had no effect on basal ppET-1 or ET
B
-R expression but markedly attenuated the deformation-induced expression of these gene products, and these effects were reversed by the B
2
receptor antagonist icatibant (Hoe 140) and by the NO synthase inhibitor
N
G
-nitro-
l
-arginine. Candesartan (1 μmol/L) mimicked the inhibitory effect of irbesartan. Moreover, reporter gene analysis with a rat ppET-1 promoter-luciferase construct transiently transfected into porcine aortic cultured endothelial cells revealed that the inhibitory effect of both ramiprilat and irbesartan on deformation-induced ppET-1 expression is species independent and mediated at the level of transcription. In addition, RT-PCR analysis detected only AT
1
receptor expression in the endothelium-intact rabbit jugular vein, and neither irbesartan nor ramiprilat affected endothelial NO synthase expression. Thus, ACE inhibitors and AT
1
receptor antagonists are capable of suppressing deformation-induced gene expression in the vessel wall in both an autocrine (ppET-1) and a paracrine (ET
B
-R) manner via a common mechanism of action that constitutes a B
2
receptor–mediated increase in endothelial NO release.
Endothelial NO Synthase Overexpression Inhibits Lesion Formation in Mouse Model of Vascular Remodeling
Authors: Kawashima Seinosuke , Yamashita Tomoya , Ozaki Masanori , Ohashi Yoshitaka , Azumi Hiroshi , Inoue Nobutaka , Hirata Ken-ichi , Hayashi Yoshitake , Itoh Hiroshi , Yokoyama Mitsuhiro
Published: June 2011

Abstract
—NO produced by endothelial NO synthase (eNOS) plays important roles in the regulation of vascular tone and structure. The purpose of this study was to clarify the role of eNOS-derived NO on vascular remodeling by use of eNOS-transgenic (eNOS-Tg) mice. The common carotid artery was ligated just proximal to the carotid bifurcation. Four weeks later, the proximal carotid artery of the ligation site was histologically examined. In this vascular remodeling model, the endothelium remains uninjured, but neointimal and medial thickening occurs in combination with a reduction in vascular diameter at the proximal portion of the ligation. At 4 weeks after ligation, the respective neointimal and medial areas in wild-type mice were 17 200±1100 and 24 300±1500 μm
2
, whereas both were reduced to 8000±1900 (
P
<0.01) and 18 400±700 μm
2
(
P
<0.01) in eNOS-Tg mice (n=8). Total vascular area was not different between the 2 genotypes.
N
G
-Nitro-
l
-arginine methyl ester treatment increased neointimal and medial areas to the same extent in both genotypes. Leukocyte infiltration was observed in the luminal side of the vessel, but the number of infiltrating cells was significantly attenuated in eNOS-Tg mice compared with wild-type mice. This reduction of leukocyte infiltration in eNOS-Tg mice was associated with reduced expressions of intracellular adhesion molecule-1 and vascular cellular adhesion molecule-1 on the endothelium. In conclusion, chronic eNOS overexpression in the endothelium reduced leukocyte infiltration and inhibited neointimal formation and medial thickening. Our data provide the evidence for the regulatory role of NO from the endothelium on vascular structure integrity.
Mitogen-Induced p53 Downregulation Precedes Vascular Smooth Muscle Cell Migration From Healthy Tunica Media and Proliferation
Authors: Rodríguez-Campos Antonio , Ruiz-Enríquez Pilar , Faraudo Susanna , Badimon Lina
Published: June 2011

Abstract
—The tumor suppressor protein p53 plays an important role in the cell-cycle G
1
and G
2
checkpoints. In response to DNA damage, p53 can induce the transcription of p21, which inhibits the activation of various G
1
cyclin/cyclin-dependent kinase complexes. It is not known whether p53 plays a role in the initial migration of vascular smooth muscle cells from the arterial tunica media (mVSMCs). In this study, we have investigated whether mVSMC migration from healthy tunica media of young pigs and proliferation are regulated by p53. After 6 hours of incubation in mitogen-rich medium, explanted porcine tunica media tissue showed complete downregulation of p53 protein and p53 mRNA. The blockage of gene activity was not due to DNA methylation at the 5′ control region of the gene. The mVSMC outgrowth did not show p53 expression. Mitogen-depletion of cultured p53
−
/mVSMCs did not restore p53 expression. Incubation of explanted porcine tunica media tissue in mitogen-deprived medium increased p53 protein content and blocked mVSMC outgrowth from the explant. As in p53-deficient rodent cells, mVSMCs incubated with colcemid overrode the spindle-dependent checkpoint, giving polyploidy and chromosomal pairing. UV-induced DNA damage in mVSMCs incubated with mitogen-free medium induced p53 expression and apoptotic cell death showing DNA nucleosomal laddering. However, UV-irradiated mVSMCs incubated in mitogen-rich medium did not express p53 and did not show cell death. In conclusion, our results demonstrate that early mVSMC migration from the tunica media requires mitogen-induced suppression of p53 that is highly expressed in contractile mVSMCs residing in the healthy vessel wall.
Cellular Senescence After Single and Repeated Balloon Catheter Denudations of Rabbit Carotid Arteries
Authors: Fenton Mark , Barker Steve , Kurz David J. , Erusalimsky Jorge D.
Published: June 2011

Abstract
—The hypothesis that increased cellular proliferation in the vasculature may lead to replicative senescence has been tested in a model of neointima formation. We have used a biomarker of replicative senescence, senescence-associated β-galactosidase (SA-β-gal), to detect senescence in rabbit carotid arteries subjected to single and double balloon denudations. We found an accumulation of senescent cells in the neointima and media of all injured vessels, in contrast to the near absence of such cells in control vessels. The relative area occupied by SA-β-gal–positive cells was higher in vessels subjected to double denudation than in those subjected to single denudation, both in the neointima (0.99% versus 0.06%, respectively;
P
<0.001) and in the media (0.11% versus 0.01%, respectively;
P
<0.02). The majority of SA-β-gal–positive cells were vascular smooth muscle cells, and a minority were endothelial cells. SA-β-gal–positive cells showed no evidence of apoptosis by use of terminal deoxynucleotidyl transferase–mediated dUTP nick end-labeling. Our results indicate that the proliferative response that follows intraluminal injury to the artery leads to the emergence of senescent endothelial and smooth muscle cells. The demonstration that vascular cell senescence can occur in vivo suggests that this process may be involved in cardiovascular pathologies that have a proliferative component.
Flow-Induced Constriction in Arterioles of Hyperhomocysteinemic Rats Is Due to Impaired Nitric Oxide and Enhanced Thromboxane A
2
Mediation
Authors: Bagi Zsolt , Ungvari Zoltan , Szollár Lajos , Koller Akos
Published: June 2011

Abstract
—Hyperhomocysteinemia (HHcy) is thought to promote arteriosclerosis and peripheral arterial disease, in part by impairing the function of endothelium. Because flow-induced dilation is mediated by the endothelium, we hypothesized that HHcy alters this response by interfering with the synthesis/action of NO and prostaglandins. Thus, changes in the diameter of isolated, pressurized (at 80 mm Hg) gracilis skeletal muscle arterioles (diameter ≈170 μm) from control and methionine diet–induced HHcy rats were investigated with videomicroscopy. Increases in intraluminal flow (from 0 to 25 μL/min) resulted in dilations of control arterioles (maximum, 34±4 μm). In contrast, increases in flow elicited constrictions of HHcy arterioles (−36±3 μm). In control arterioles, the NO synthase inhibitor
N

ω

-nitro-
l
-arginine-methyl ester significantly attenuated (≈50%) dilation, whereas the additional administration of indomethacin, an inhibitor of cyclooxygenase, eliminated flow-induced dilation. In the arterioles of HHcy rats, flow-induced constriction was not affected by
N

ω

-nitro-
l
-arginine-methyl ester, whereas it was abolished by indomethacin or the prostaglandin H
2
/thromboxane A
2
(TXA
2
) receptor antagonist SQ 29,548 or the TXA
2
synthase inhibitor CGS 13,080. Thus, in HHcy, increases in intraluminal flow elicit constrictions of skeletal muscle arterioles due to the impaired NO and enhanced TXA
2
mediation of the response, alterations that likely contribute to the development of peripheral arterial disease.
Progesterone, but Not Medroxyprogesterone, Inhibits Vascular Cell Adhesion Molecule-1 Expression in Human Vascular Endothelial Cells
Authors: Otsuki Michio , Saito Hiroshi , Xu Xin , Sumitani Satoru , Kouhara Haruhiko , Kishimoto Tadamitsu , Kasayama Soji
Published: June 2011

Abstract
—It has been shown that ovarian steroid hormones can reduce the incidence of cardiovascular disease in postmenopausal women. As hormone replacement therapy for postmenopausal women, progestins are added to estrogens to eliminate the increased risk of endometrial cancer. However, the effects of progestins on the atherogenic process have not been well understood. In the present study, we examined the effects of progestins on the expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs). Immunocytochemical analysis revealed the presence of progesterone receptors in HUVECs. Progesterone clearly inhibited tumor necrosis factor-α–activated expression of VCAM-1 protein and its mRNA in HUVECs. Synthetic progesterone receptor agonist R5020 also inhibited the tumor necrosis factor-α–activated VCAM-1 expression, whereas medroxyprogesterone acetate (MPA) failed to do so. Electrophoretic mobility shift assays demonstrated that progesterone, but not MPA, inhibited DNA binding of the transcription nuclear factor-κB, which is critical for the inducible expression of VCAM-1. Because the expression of VCAM-1 is one of the earliest events that occurs in the atherogenic process, this adhesion molecule might be a target molecule for progesterone on vascular walls. The contrasting effects of progesterone and MPA seem clinically important, inasmuch as MPA is a widely used progestin in the regimen of hormone replacement therapy.
Effect of Oral Postmenopausal Hormone Replacement on Progression of Atherosclerosis
Authors: Angerer Peter , Störk Stefan , Kothny Wolfgang , Schmitt Philip , von Schacky Clemens
Published: June 2011

Abstract
—Postmenopausal hormone replacement therapy (HRT) is associated with low cardiovascular morbidity and mortality in epidemiological studies. Yet, no randomized trial has examined whether HRT is effective for prevention of coronary heart disease (CHD) in women with increased risk. The objective of this study was to determine whether HRT can slow progression of atherosclerosis, measured as intima-media thickness (IMT) in carotid arteries. Carotid IMT is an appropriate intermediate end point to investigate clinically relevant effects on atherogenesis. This randomized, controlled, observer-blind, clinical, single-center trial enrolled 321 healthy postmenopausal women with increased IMT in ≥1 segment of the carotid arteries. For a period of 48 weeks, subjects received either 1 mg/d 17β-estradiol continuously plus 0.025 mg gestodene for 12 days every month (standard-progestin group), or 1 mg 17β-estradiol plus 0.025 mg gestodene for 12 days every third month (low-progestin group), or no HRT. Maximum IMT in 6 carotid artery segments (common, bifurcation, and internal, both sides) was measured by B-mode ultrasound before and after intervention. HRT did not slow IMT progression in carotid arteries. Mean maximum IMT in the carotid arteries increased by 0.02±0.05 mm in the no HRT group and by 0.03±0.05 and 0.03±0.05 mm, respectively, in the HRT groups (
P
>0.2). HRT significantly decreased LDL cholesterol, fibrinogen, and follicle-stimulating hormone. In conclusion, 1 year of HRT was not effective in slowing progression of subclinical atherosclerosis in postmenopausal women at increased risk.
Antibodies to Oxidized LDL in Relation to Carotid Atherosclerosis, Cell Adhesion Molecules, and Phospholipase A
2
Authors: Hulthe Johannes , Wiklund Olov , Hurt-Camejo Eva , Bondjers Göran
Published: June 2011

Abstract
—The role of the humoral immune response to oxidized low density lipoprotein (Ox-LDL) in atherogenesis is unclear and available studies are contradictory. The aims of the present study were (1) to compare antibody titers to modified LDL in a group of patients with hypercholesterolemia (n=102) with those in matched controls (n=102), (2) to analyze whether these titers were related to atherosclerosis development as measured by ultrasound, and (3) to analyze whether these titers were related to soluble cell adhesion molecules and secretory type II phospholipase A
2
in plasma. The results showed that male patients with hypercholesterolemia had lower immunoglobulin G (IgG) titers compared with those in healthy controls. In the control group, there was an inverse correlation between intima-media thickness of the carotid artery bulb and IgM titers against Ox-LDL and malondialdehyde-LDL (
r
=−0.35,
P
=0.001; and
r
=−0.31,
P
=0.003, respectively). In the patient group, however, only weak associations were seen. IgG titers were positively associated with soluble intercellular adhesion molecule-1, soluble E-selectin, and secretory type II phospholipase A
2
. Taken together, the results of this study support the concept that the humoral immune response against Ox-LDL may be protective in early atherosclerosis. The pattern, however, is complex, and the role of the immune response may differ in different patient groups as well as at different stages of the disease.
Reactive Oxygen Species Regulate Heat-Shock Protein 70 via the JAK/STAT Pathway
Authors: Madamanchi Nageswara R. , Li Suzhen , Patterson Cam , Runge Marschall S.
Published: June 2011

Abstract
—Reactive oxygen species (ROS) such as hydrogen peroxide (H
2
O
2
) activate intracellular signal transduction pathways implicated in the pathogenesis of cardiovascular disease. H
2
O
2
is a mitogen for rat vascular smooth muscle cells (VSMCs), and protein tyrosine phosphorylation is a critical event in VSMC mitogenesis. Therefore, we investigated whether the mitogenic effects of H
2
O
2
, such as stimulation of extracellular signal–regulated kinase (ERK)2, are mediated via activation of cytoplasmic Janus tyrosine kinases (JAKs). JAK2 was activated rapidly in VSMCs treated with H
2
O
2
, and signal transducers and activators of transcription (STAT) STAT1 and STAT3 were tyrosine-phosphorylated and translocated to the nucleus in a JAK2-dependent manner. Inhibition of JAK2 activity with AG-490 partially inhibited H
2
O
2
-induced ERK2 activity, suggesting that JAK2 is upstream of the Ras/Raf/mitogen-activated protein kinase–ERK/ERK mitogenic pathway. Because heat-shock proteins (HSPs) can protect cells from ROS, we investigated the effect of H
2
O
2
on HSP expression. H
2
O
2
stimulated HSP70 expression in a time-dependent manner, and AG-490 abolished H
2
O
2
-induced HSP70 expression. H
2
O
2
activated the HSP70 promoter via enhanced binding of STATs to cognate binding sites in the promoter. Regulation of chaperones such as HSP70 via activation of the JAK/STAT pathway suggests that in addition to its growth-promoting effects, this pathway may help VSMCs adapt to oxidative stress.
Insulin-Like Growth Factor Binding Protein-4 Protease Produced by Smooth Muscle Cells Increases in the Coronary Artery After Angioplasty
Authors: Bayes-Genis Antoni , Schwartz Robert S. , Lewis Debra A. , Overgaard Michael T. , Christiansen Michael , Oxvig Claus , Ashai Khalid , Holmes David R. , Conover Cheryl A.
Published: June 2011

Abstract
—Insulin-like growth factor (IGF)-I stimulates vascular smooth muscle cell (VSMC) migration and proliferation, which are fundamental to neointimal hyperplasia in postangioplasty restenosis. IGF-I action is modulated by several high-affinity IGF binding proteins (IGFBPs). IGFBP-4 is the predominant IGFBP produced by VSMCs and is a potent inhibitor of IGF-I action. However, specific IGFBP-4 proteases can cleave IGFBP-4 and liberate active IGF-I. In this study, we document IGFBP-4 protease produced by human and porcine coronary artery VSMCs in culture as pregnancy-associated plasma protein-A (PAPP-A). This was shown by a distinctive IGFBP-4 cleavage pattern, specific inhibition of IGFBP-4 protease activity with PAPP-A polyclonal antibodies, and immunorecognition of PAPP-A by monoclonal antibodies. Furthermore, we found a 2-fold increase in IGFBP-4 protease activity in injured porcine VSMC cultures in vitro (
P
<0.05). We also evaluated IGFBP-4 protease/PAPP-A expression in vivo after coronary artery balloon injury. Twenty-five immature female pigs underwent coronary overstretch balloon injury, and vessels were examined at defined time points after the procedure. Abundant PAPP-A expression was observed in the cytoplasm of medial and neointimal cells 7, 14, and 28 days after angioplasty (
P
<0.01 vs control). The highest PAPP-A labeling indices were located in the neointima (36.1±2.1%) and the media (31.7±1.2%) 28 days after injury. Western blot analysis confirmed increased PAPP-A in injured vessels. PAPP-A, a regulator of IGF-I bioavailability through proteolysis of IGFBP-4, is thus expressed by VSMCs in vitro and in restenotic lesions in vivo. These results suggest a possible role for PAPP-A in neointimal hyperplasia.
Lack of Triglyceride-Lowering Properties of Fish Oil in Apolipoprotein E–Deficient Mice
Authors: Asset G. , Baugé E. , Fruchart J. C. , Dallongeville J.
Published: June 2011

Abstract
—Fish oil is a potent triglyceride (TG)-lowering agent in humans. The goal of the present study was to assess the contribution of decreased triglyceride synthesis and of apoE in mediation of the triglyceride-lowering effect of fish oil. To this end, apoE-deficient mice and wild-type control mice were supplemented with either coconut oil, sunflower oil, or fish oil (20% wt/wt) for 2 weeks. Compared with coconut oil and sunflower oil, fish oil reduced the concentrations of cholesterol and triglycerides in the wild-type mice, whereas it had no effect on cholesterol concentration and it had a triglyceride–raising effect in apoE-deficient mice. The latter was due to increased triglyceride concentrations in the
d
<1.019 g/mL plasma density fraction. In apoE-deficient mice, but not in wild-type mice, the postprandial triglyceride area under the curve was higher after an intragastric load of fish oil than after a sunflower oil load. These data indicate an impairment of triglyceride metabolism in the fish oil–fed apoE-deficient mice. Compared with coconut oil and sunflower oil, fish oil lowered triglyceride production rates measured with the Triton method in both wild-type (
P
<0.0001) and apoE-deficient mice (
P
<0.0001). Similarly, in vitro lipoprotein lipase–mediated lipolysis of VLDL was lowered in the fish oil–fed wild-type and apoE-deficient mice, suggesting an alteration in VLDL lipolysis independent of the mice genotype. In conclusion, fish oil does not decrease triglyceride concentrations in apoE-deficient mice despite reducing triglyceride production rates, suggesting that decreased triglyceride synthesis is not sufficient to lower triglyceride concentrations in mice. ApoE appears to be necessary for fish oil to lower plasma triglyceride concentrations, indicating a critical role of apoE in this process.
Impact of Apolipoprotein(a) on In Vitro Angiogenesis
Authors: Schulter V. , Koolwijk P. , Peters E. , Frank S. , Hrzenjak A. , Graier W. F. , van Hinsbergh V. W. M. , Kostner G. M.
Published: June 2011

Abstract
—Angiostatin, which consists of the kringle I–IV domains of plasminogen and which is secreted into urine, is an efficient inhibitor of angiogenesis and tumor growth. Because
N
-terminal apolipoprotein(a) [apo(a)] fragments, which also contain several types of kringle IV domains, are found in urine as well, we evaluated the potential angiostatic properties of these urinary apo(a) fragments and of a recombinant form of apo(a) [r-apo(a)]. We used human microvascular endothelial cell (hMVEC)–based in vitro assays of tube formation in 3-dimensional fibrin matrixes. Purified urinary apo(a) fragments or r-apo(a) inhibited the basic fibroblast growth factor/tumor necrosis factor-α–induced formation of capillary-like structures. At concentrations varying from 0.2 to 10 μg/mL, urinary apo(a) fragments inhibited tube formation by as much as 70%, whereas there was complete inhibition by r-apo(a). The highest concentrations of both inhibitors also reduced urokinase plasminogen activator production of basic fibroblast growth factor–induced hMVEC proliferation. The inhibitors had no effect on plasminogen activator inhibitor-1 expression. If our in vitro model for angiogenesis is valid for the in vivo situation as well, our data point toward the possibility that apo(a) may also be physiologically operative in modulating angiogenesis, as the concentration of free apo(a) found in humans exceeds that tested herein.
Thrombomodulin Promoter Mutations, Venous Thrombosis, and Varicose Veins
Authors: Le Flem Léna , Mennen Louise , Aubry Marie-Laurence , Aiach Martine , Scarabin Pierre-Yves , Emmerich Joseph , Alhenc-Gelas Martine
Published: June 2011

Abstract
—We analyzed the distal promoter region of the thrombomodulin (TM) gene (nucleotides −300 to −2052) in subjects from the Paris Thrombosis Study (PATHROS), a French case-control study of venous thrombosis, to identify polymorphisms that might modify TM gene expression. Eight novel mutations were found in the 40 DNA samples initially screened. Two of these mutations (−1748G/C and −1208/−1209 del TT) were frequent. One rare transition (−1166G/A) might have functional consequences owing to its position. These 3 mutations were screened for in the entire study population of 327 patients and 398 controls. None of the 3 was significantly associated with thrombosis. Interestingly, the −1208/−1209 TT deletion was associated with varicose veins in the patients. This mutation was in tight linkage disequilibrium with the +1418 C/T change in the coding sequence, a known polymorphism that predicts an Ala 455 Val substitution in the sixth epidermal growth factor–like TM module, a domain previously implicated in the proliferative functions of TM. This linkage suggests that the Ala 455 Val mutation may promote changes in these functions and thus be involved in varicose vein formation.