bluuebunny/crossref_metadata_2025 huggingface dataset:
IDL Composition and Angiographically Determined Progression of Atherosclerotic Lesions During Simvastatin Therapy
Authors: Sutherland Wayne H. F. , Restieaux Norma J. , Nye Edwin R. , Williams Michael J. A. , de Jong Sylvia A. , Robertson M. Clare , Walker Heather L.
Published: June 2011

Abstract
—Some patients with coronary artery disease experience continued progression of one or more coronary lesions despite treatment with drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and markedly lower plasma cholesterol levels. We examined relationships between the progression of coronary artery lesions and plasma lipoproteins, in particular intermediate density lipoprotein (IDL) and its composition, in 38 patients with coronary artery disease who had been treated with simvastatin for 2 years. Patients were given lipid-lowering dietary advice; 3 months later they were started on simvastatin therapy (10 mg/d) for 1 month, and after review of their plasma cholesterol levels, the dose was increased to 20 mg/d and later to 40 mg/d if the target level of plasma cholesterol had not been attained. Progression of lesions was determined by serial quantitative coronary angiography (variability of 5.5%) and was defined as an increase in percent diameter stenosis (%S)≥10%; regression was defined as a decrease in %S ≥10%. The proportions of cholesteryl esters (CEs) and free cholesterol decreased significantly (
P
<.001), and proportions of protein and triglycerides increased significantly (
P
<.001) in IDL during simvastatin therapy. The CE content of IDL decreased significantly (−7.2 weight [wt]%, n=20,
P
<.001) in nonprogressors (patients who did not show progression of any lesions) and did not change significantly (−1.8 wt%, n=14,
P
=.36) in progressors (patients who showed progression of one or more lesions without regression of any lesion). This decrease in IDL CE content in nonprogressors was significantly (
P
=.01) different compared with the corresponding change in patients classified as progressors. Mean plasma cholesterol concentration tended to increase in progressors (0.47 mmol/L) and tended to decrease in nonprogressors (−0.39 mmol/L) during the initial 3-month diet period, and these changes were significantly different (
P
=.02). Furthermore, this change in plasma cholesterol level during the initial diet period was correlated significantly with the change in IDL CE content during the entire study (
r
=.348, n=38,
P
=.03). These data suggest that IDL CE content may be a determinant of progression of coronary lesions and may be influenced by compliance with or metabolic response to lipid-lowering dietary advice in patients with coronary artery disease during simvastatin treatment.
Factor VIIa Response to a Fat-Rich Meal Does Not Depend on Fatty Acid Composition
Authors: Mennen Louise , de Maat Moniek , Meijer Gert , Zock Peter , Grobbee Diederick , Kok Frans , Kluft Cornelis , Schouten Evert
Published: June 2011

Abstract
—A fat-rich meal increases activated factor VII (FVIIa), but it is not clear whether this increase depends on the fatty acid composition of the meal. Therefore, we studied the FVIIa response to fat-rich meals with different fatty acid composition in a randomized controlled crossover trial and investigated whether this response is mediated by an increase in serum triglycerides. Elderly women (> 60 years, n=91) received on separate days four different fat-rich breakfasts (50 energy percent [en%] of fat) and a control breakfast (1.5 en% fat; crossover). The fat-rich breakfasts differed in fatty acid composition: one rich in palmitic acid (21.7 g), one in stearic acid (18.6 g), and the other two in linoleic and linolenic acid−one with a ratio 3:1 (12.5/3.9 g) and the other with a ratio of 15:1 (18.8/1.2 g). At 8
am
before the breakfast (fasting) and at 1 and 3
pm,
blood samples were taken, in which FVIIa and serum triglycerides were measured. FVIIa response to the fat-rich meals ranged from 11.6 mU/mL (95% confidence interval: 8.3,14.9) on the stearic meal to 15.9 mU/mL (12.0,19.8) on the linoleic/linolenic 15:1 meal at 1
pm
and from 14.9 mU/mL (10.6,19.2) to 21.1 mU/mL (16.6,25.6) for the same meals at 3
pm
. The responses did not differ between the fat-rich meals. After the control breakfast, FVIIa decreased, with 6.3 mU/mL (3.9,8.7) at 1
pm
and 8.7 mU/mL (6.3,11.1) at 3
pm
. The triglyceride response was lower after both linoleic/linolenic rich breakfasts compared with the palmitic and stearic breakfast (
P
<.05) and was not associated with the FVIIa response at any of the blood sampling occasions. The results of this study show that the response of FVIIa to a fat-rich meal is independent of its fatty acid composition and is not mediated by serum triglycerides.
Lysophosphatidylcholine Is Involved in the Antigenicity of Oxidized LDL
Authors: Wu Ruihua , Huang Yui Hui , Elinder Liselotte Schäfer , Frostegård Johan
Published: June 2011

Abstract
—Lysophosphatidylcholine (LPC) is formed by hydrolysis of PC in low density lipoprotein (LDL) and cell membranes by phospholipase A
2
or by oxidation. Oxidized (ox) LDL activates endothelial cells, an effect mimicked by LPC. oxLDL also has the capacity to activate T and B cells, and antibody titers to oxLDL are related to the degree of atherosclerosis. The antigen in oxLDL responsible for its immune-stimulatory capacity is not well characterized, and we hypothesized that LPC was involved. We demonstrate herein the presence of antibodies against LPC, both of the IgG and IgM isotype, in 210 healthy individuals. This antibody reactivity was not specifically related to oxidation of the fatty acid moiety in LPC, since LPC containing only palmitic acid showed antibody titers equivalent to those of LPC containing unsaturated fatty acids. Antibody titers to PC were low compared with LPC, and hydrolysis of PC at the
sn
-2 position is thus essential for immune reactivity. There was a close correlation between anti-oxLDL and anti-LPC antibodies. Furthermore, LPC competitively inhibited anti-oxLDL reactivity, which indicates that LPC may explain a significant part of the immune-stimulatory properties of oxLDL. LPC, being a lipid, is not likely to be an antigen itself. Instead, LPC could form immunogenic complexes with peptides, which may induce and potentiate immune reactions in the vessel wall. This study adds to the evidence that LPC is an important component of oxLDL and emphasizes the potential role of phospholipase A
2
in atherosclerosis.
Alcohol Withdrawal–Induced Change in Lipoprotein(a)
Authors: Paassilta Marita , Kervinen Kari , Linnaluoto Markku , Kesäniemi Y. Antero
Published: June 2011

Abstract
—Lipoprotein(a) [Lp(a)] is an important risk factor for cardiovascular disease. Alcohol is one of the few nongenetic factors that lower Lp(a) levels, but the metabolic mechanisms of this action are unknown. Alcohol inhibits the growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis. Alcohol might also affect IGF-binding protein-1 (IGFBP-1), which is an acute inhibitor of IGF-I. We studied how alcohol withdrawal affects Lp(a) levels and the GH/IGF-I/IGFBP-1 axis. Male alcohol abusers (n=27; 20 to 64 years old) were monitored immediately after alcohol withdrawal for 4 days. Twenty-six healthy men, mainly moderate drinkers, served as control subjects. Fasting blood samples were drawn to determine Lp(a), IGF-I, and IGFBP-1 (by ELISA, RIA, and immunoenzymometric assay, respectively). Nocturnal (12 hours) urine collection was performed in 9 alcoholics and 11 control subjects for GH analyses (RIA). The groups were similar in age and body mass index. Lp(a), GH, and IGF-I tended to be lower and IGFBP-1 higher in the alcoholics immediately after alcohol withdrawal than in the control subjects. During the 4-day observation in alcoholics, Lp(a) levels increased by 64% and IGF-I levels by 41%, whereas IGFBP-1 levels decreased by 59% (
P
<.001 after ANOVA for all comparisons). Urinary GH levels tended to decline. The increase in Lp(a) correlated inversely with the changes in IGFBP-1 (
r
=−.63,
P
<.001, n=27) and GH (
r
=−.70,
P
<.05, n=9), but not with IGF-I. In multiple regression analysis, the main predictors for the increase in Lp(a) were IGFBP-1 and urinary GH. In conclusion, alcohol withdrawal induces interrelated and potentially atherogenic changes in Lp(a) and IGFBP-1 levels.
Laminar Shear Stress
Authors: Traub Oren , Berk Bradford C.
Published: June 2011

Abstract
—Mechanical forces are important modulators of cellular function in many tissues and are particularly important in the cardiovascular system. The endothelium, by virtue of its unique location in the vessel wall, responds rapidly and sensitively to the mechanical conditions created by blood flow and the cardiac cycle. In this study, we examine data which suggest that steady laminar shear stress stimulates cellular responses that are essential for endothelial cell function and are atheroprotective. We explore the ability of shear stress to modulate atherogenesis via its effects on endothelial-mediated alterations in coagulation, leukocyte and monocyte migration, smooth muscle growth, lipoprotein uptake and metabolism, and endothelial cell survival. We also propose a model of signal transduction for the endothelial cell response to shear stress including possible mechanotransducers (integrins, caveolae, ion channels, and G proteins), intermediate signaling molecules (c-Src, ras, Raf, protein kinase C) and the mitogen activated protein kinases (ERK1/2, JNK, p38, BMK-1), and effector molecules (nitric oxide). The endothelial cell response to shear stress may also provide a mechanism by which risk factors such as hypertension, diabetes, hypercholesterolemia, and sedentary lifestyle act to promote atherosclerosis.
Localizing Role of Hemodynamics in Atherosclerosis in Several Human Vertebrobasilar Junction Geometries
Authors: Ravensbergen J. , Ravensbergen J. W. , Krijger J. K. B. , Hillen B. , Hoogstraten H. W.
Published: June 2011

Abstract
—Atherosclerosis is a common finding in the vertebrobasilar junction and in the basilar artery. Several theories try to link the process of atherogenesis with the forces exerted by the flowing blood. An attractive relation has been found between the locations in vessels at which atherosclerotic plaques are often present and the locations in models where complicated flow patterns exist. Most of the studies provided data on bifurcations. Finding a similar relation in an arterial confluence would certainly add to the credibility of the (causal) relationship between hemodynamics and atherosclerosis. Further support can be provided if variations of the geometry result in changes of the location of the atherosclerotic lesions, corresponding to the changes of the flow force distribution. In our previous numerical and experimental work, the influence of geometric and hemodynamic parameters, such as asymmetrical inflow, confluence angle, and blunting of the apex, on the flow in vertebrobasilar junction models has been investigated in detail. Recirculation areas and distribution of the wall shear stress have been computed. In this anatomic study, the effect of modulation of these geometric and hemodynamic parameters on the flow pattern is compared with the size and location of plaques in human vertebrobasilar junctions and basilar arteries. In addition, a comparison is made between the preferential areas of atherosclerotic plaques in junctions and bifurcations to demonstrate the localizing role of hemodynamics in atherogenesis. The apex of the vertebrobasilar junction and the lateral walls of the basilar artery appeared to be prone to atherosclerosis. In 43 of 85 vertebrobasilar junctions, a plaque was found at the apex. Furthermore, the summed plaque thickness at both lateral walls differs significantly (paired
t
test,
P
=.03) from that at the walls facing the pons and the skull base. In contrast, several authors found that the lateral walls of the mother vessel and the apex in bifurcations are often spared. Modulation of the various parameters in the models changed the size of the regions with low wall shear stress and/or recirculation areas dramatically. A comparable effect was found in the occurrence of plaques in the human vertebrobasilar junction; eg, for an atherosclerotic plaque at the apex, a predicted probability larger than 0.5 was computed for blunted apexes and for sharp-edged apexes with a confluence angle exceeding 90°. Apparently, two geometric risk factors for an atherosclerotic plaque at the apex can be distinguished: a blunted apex and a large confluence angle.
Vascular Endothelial Cell Regulation of Extracellular Matrix Collagen
Authors: Myers Paul R. , Tanner Miles A.
Published: June 2011

Abstract
—Endothelium-derived products have been implicated in the regulation of vascular wall structure through their effects on extracellular matrix metabolism. The purpose of this study was to further understand the paracrine mechanisms underlying endothelial cell regulation of extracellular matrix metabolism by testing the hypothesis that endothelium-derived nitric oxide decreases the concentration of soluble collagens derived from vascular smooth muscle cells (VSMCs). Porcine coronary endothelium and VSMCs were grown under a coculture configuration to assess the paracrine effects of nitric oxide produced by the endothelium on VSMC collagen types I and III. Endogenous endothelial cell nitric oxide production was blocked with
N
ω
-nitro-
l
-arginine methyl ester. Collagen type I and type III were quantitatively measured using an enzyme-linked immunosorbent assay method. The endothelium elicited a time-dependent increase in the concentration of soluble VSMC-derived collagen type I; in contrast, collagen type III was decreased. After inhibition of nitric oxide production, there was a marked increase in both collagen types I and III concentration. These results demonstrated that endothelium-derived nitric oxide differentially alters collagen subtypes produced by VSMCs. The data support the hypothesis that nitric oxide functions via a paracrine mechanism to decrease VSMC collagen types I and III concentration, a finding consistent with an integral role for the endothelium in modulating extracellular matrix metabolism.
Soluble Cell Adhesion Molecules in Hypertriglyceridemia and Potential Significance on Monocyte Adhesion
Authors: Abe Yasunori , El-Masri Bassem , Kimball Kay T. , Pownall Henry , Reilly Christopher F. , Osmundsen Karin , Smith C. Wayne , Ballantyne Christie M.
Published: June 2011

Abstract—Hypertriglyceridemia may contribute to the development of atherosclerosis by increasing expression of cell adhesion molecules (CAMs). Although the cellular expression of CAMs is difficult to assess clinically, soluble forms of CAMs (sCAMs) are present in the circulation and may serve as markers for CAMs. In this study, we examined the association between sCAMs and other risk factors occurring with hypertriglyceridemia, the effect of triglyceride reduction on sCAM levels, and the role of soluble vascular cell adhesion molecule-1 (sVCAM-1) in monocyte adhesion in vitro. Compared with normal control subjects (n=20), patients with hypertriglyceridemia and low HDL (n=39) had significantly increased levels of soluble intercellular adhesion molecule-1 (sICAM-1) (316±28.8 versus 225±16.6 ng/mL), sVCAM-1 (743±52.2 versus 522±43.6 ng/mL), and soluble E-selectin (83±5.9 versus 49±3.6 ng/mL). ANCOVA showed that the higher sCAM levels in patients occurred independently of diabetes mellitus and other risk factors. In 27 patients who received purified n-3 fatty acid (Omacor) 4 g/d for ≥7 months, triglyceride level was reduced by 47±4.6%, sICAM-1 level was reduced by 9±3.4% (P=.02), and soluble E-selectin level was reduced by 16±3.2% (P<.0001), with the greatest reduction in diabetic patients. These results support previous in vitro data showing that disorders in triglyceride and HDL metabolism influence CAM expression and treatment with fish oils may alter vascular cell activation. In a parallel-plate flow chamber, recombinant sVCAM-1 at the concentration seen in patients significantly inhibited adhesion of monocytes to interleukin-1–stimulated cultured endothelial cells under conditions of flow by 27.5±7.2%. Thus, elevated sCAMs may negatively regulate monocyte adhesion.
Upregulation of VCAM-1 and ICAM-1 at Atherosclerosis-Prone Sites on the Endothelium in the ApoE-Deficient Mouse
Authors: Nakashima Yutaka , Raines Elaine W. , Plump Andrew S. , Breslow Jan L. , Ross Russell
Published: June 2011

Abstract
—Focal recruitment of monocytes and lymphocytes is one of the earliest detectable cellular responses in the formation of lesions of atherosclerosis. This localized accumulation of leukocytes is a multistep process in which the endothelium remains intact and may regulate leukocyte recruitment by expressing specific adhesion molecules. To examine the relationship of adhesion molecule expression to initiation factors and the sites of lesion formation, we analyzed the expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and platelet–endothelial cell adhesion molecule-1 (PECAM-1) en face on the aortic endothelium of control mice and homozygous apolipoprotein E–deficient (ApoE −/−) mice that develop complex lesions of atherosclerosis similar to those in humans. In control mice, VCAM-1 staining was weak and limited to sites of altered blood flow. In contrast, in the ApoE −/− mice, VCAM-1 appeared to be localized over the surface of groups of endothelial cells in lesion-prone sites. Expression of VCAM-1 preceded lesion formation, and increased expression above control levels appeared to be correlated with the extent of exposure to plasma cholesterol. Although ICAM-1 was the most prominent adhesion molecule in lesion-prone sites, its expression appeared to be independent of plasma cholesterol levels and was upregulated in both ApoE −/− and control mice. At lesion-prone sites associated with altered blood flow, ICAM-1 was located over the surface of each endothelial cell and on microvilli, whereas VCAM-1 was confined to the cell periphery in non–lesion-prone sites. PECAM-1 was localized at the cell periphery throughout the aorta, and its expression did not appear to be regulated. Thus, the levels, localization, and characteristics of expression of VCAM-1, ICAM-1, and PECAM-1 appear to be differentially regulated. Upregulation of VCAM-1 and ICAM-1 is associated with sites of lesion formation.
Intraluminal Pressure Is Essential for the Maintenance of Smooth Muscle Caldesmon and Filamin Content in Aortic Organ Culture
Authors: Birukov Konstantin G. , Bardy Nathalie , Lehoux Stéphanie , Merval Régine , Shirinsky Vladimir P. , Tedgui Alain
Published: June 2011

Abstract
—Different forms of mechanical stimulation are among the physiological factors constantly acting on the vessel wall. We previously demonstrated that subjecting vascular smooth muscle cells (VSMCs) in culture to cyclic stretch increased the expression of high-molecular-weight caldesmon, a marker protein of a differentiated, contractile, VSMC phenotype. In the present work the effects of mechanical factors, in the form of circumferential stress and shear stress, on the characteristics of SM contractile phenotype were studied in an organ culture of rabbit aorta. Application of an intralumininal pressure of 80 mm Hg to aortic segments cultured in Dulbecco’s modified Eagle’s medium containing 20% fetal calf serum for 3 days prevented the decrease in high-molecular-weight caldesmon content (70±4% of initial level in nonpressurized vessel, 116±17% at 80 mm Hg) and filamin content (80±5% in nonpressurized vessel, 100±2% at 80 mm Hg). SM myosin and low-molecular-weight caldesmon contents showed no dependence on vessel pressurization. Neither endothelial denudation nor alteration of intraluminal flow rates affected marker protein content in 3-day vessel culture, thus excluding the possibility of any shear or endothelial effects. Maintenance of high high-molecular-weight caldesmon and filamin levels in the organ cultures of pressurized and stretched vessels demonstrates the positive role of mechanical factors in the control of the VSMC differentiated phenotype.
Oxidized Cholesterol in the Diet Accelerates the Development of Aortic Atherosclerosis in Cholesterol-Fed Rabbits
Authors: Staprans Ilona , Pan Xian-Mang , Rapp Joseph H. , Feingold Kenneth R.
Published: June 2011

Abstract
—Oxidized lipoproteins may play a role in atherosclerosis. Recently, we have demonstrated that the levels of oxidized fatty acids in the circulation correlate directly with the quantity of oxidized fatty acids in the diet and that dietary oxidized fatty acids accelerate atherosclerosis in rabbits. The present study tests the hypothesis that oxidized cholesterol in the diet accelerates the development of atherosclerosis. Rabbits were fed a diet containing 0.33% nonoxidized cholesterol (control diet) or the same diet containing 0.33% cholesterol of which 5% was oxidized (oxidized diet). Serum cholesterol levels increased to a similar extent in both groups, with the majority of cholesterol in the β-VLDL fraction. Moreover, in the serum β-VLDL fraction and liver, there was a significant increase in the oxidized cholesterol levels. Most importantly, feeding a diet enriched in oxidized cholesterol resulted in a 100% increase in fatty streak lesions in the aorta. Western diets contain high concentrations of oxidized cholesterol products, and our results suggest that these foods may be a risk factor for atherosclerosis.
Estradiol Stimulates Apolipoprotein A-I– but Not A-II–Containing Particle Synthesis and Secretion by Stimulating mRNA Transcription Rate in Hep G2 Cells
Authors: Jin Fu-You , Kamanna Vaijinath S. , Kashyap Moti L.
Published: June 2011

Abstract
—Estrogen therapy increases plasma HDL levels, which may reduce cardiovascular risk in postmenopausal women. The mechanism of action of estrogen in influencing various steps in hepatic HDL and apolipoprotein (apo) A-I synthesis and secretion are not fully understood. In this study, we have used the human hepatoblastoma cell line (Hep G2) as an in vitro model system to delineate the effect of estradiol on multiple regulatory steps involved in hepatic HDL metabolism. Incubation of Hep G2 cells with estradiol resulted in the following statistically significant findings: (1) increased accumulation of apoA-I in the medium without affecting uptake/removal of radiolabeled HDL-protein; (2) accelerated incorporation of [
3
H]leucine into apoA-I; (3) selective increase in [
3
H]leucine incorporation into lipoprotein (LP) A-I but not LP A-I+A-II HDL particles (HDL particles without and with apoA-II, respectively); (4) increased ability of apoA-I–containing particles to efflux cholesterol from fibroblasts; (5) stimulated steady state apoA-I but not apoA-II mRNA expression; and (6) increased newly transcribed apoA-I mRNA message without effect on apoA-I mRNA half-life. The data indicate that estradiol stimulates newly transcribed hepatic apoA-I mRNA, resulting in a selective increase in LP A-I, a subfraction of HDL that is associated with decreased atherosclerotic cardiovascular disease, especially in premenopausal women.
Function of the Plasminogen/Plasmin and Matrix Metalloproteinase Systems After Vascular Injury in Mice With Targeted Inactivation of Fibrinolytic System Genes
Authors: Lijnen H. Roger , Van Hoef Berthe , Lupu Florea , Moons Lieve , Carmeliet Peter , Collen Désiré
Published: June 2011

Abstract
—The matrix metalloproteinase (MMP) system, which may be activated via the plasminogen (Plg)/plasmin system, is claimed to play a role in matrix degradation and smooth muscle cell migration. To test the role of both systems, expression of fibrinolytic and gelatinolytic activity was quantified after vascular injury in mice with targeted inactivation of tissue-type Plg activator (tPA
−/−
), urokinase-type Plg activator (uPA
−/−
), or Plg (Plg
−/−
). Neointima formation 1 week after vascular injury was impaired in uPA
−/−
and Plg
−/−
mice compared with wild-type (WT) mice or tPA
−/−
mice (reduction of neointimal area to 30% and 10% of WT, respectively). Cell accumulation at the borders of the injury was significantly (
P
<0.01) impaired compared with that in WT mice. One week after injury of the femoral artery, tPA-mediated fibrinolytic activity in arterial sections or extracts of WT, uPA
−/−
, or Plg
−/−
mice was not altered, whereas uPA activity levels in tPA
−/−
and Plg
−/−
mice were 2- to 3-fold higher than in uninjured controls. Total levels (latent plus active) of MMP-2 (gelatinase A) were increased by 2- to 4-fold, whereas the contribution of active MMP-2 represented 38% to 63% of the total in the different genotypes. MMP-9 (gelatinase B) was not detectable in the majority of control arteries, whereas total MMP-9 levels after injury were dramatically increased (up to 50-fold above the detection limit). Active MMP-9 represented 20% to 46% of total MMP-9 in WT, tPA
−/−
, and uPA
−/−
mice but was not consistently detectable in Plg
−/−
mice. Similar results were obtained in carotid arteries. Thus, the unaltered ratios of active and latent MMP-2 suggest that proMMP-2 activation may occur in the absence of tPA, uPA, or Plg, whereas no active MMP-9 was detected in the absence of Plg. The data of this study confirm a role for uPA and Plg but not for tPA in smooth muscle cell migration and neointima formation after vascular injury and indicate that impairment of these phenomena may occur despite the observed increases in MMP-2 or MMP-9 levels after vascular injury.
Distinct Promoters Induce APOBEC-1 Expression in Rat Liver and Intestine
Authors: Greeve Jobst , Axelos David , Welker Sybille , Schipper Meike , Greten Heiner
Published: June 2011

Abstract
—The expression of apolipoprotein (apo) B can be modulated by mRNA editing, a unique posttranscriptional base change in the apo B mRNA. Apo B-48, the translation product of edited apo B mRNA, is not a precursor of the atherogenic low density lipoproteins and lipoprotein(a). In humans and various other mammals, the apo B mRNA is edited in the intestine but not in the liver, which exclusively secretes apo B-100–containing lipoproteins as precursors for low density lipoprotein formation. In species such as the rat, mouse, dog, and horse, apo B mRNA is also edited in the liver, resulting in low plasma levels of low density lipoprotein. Editing of the apo B mRNA is mediated by the apo B mRNA–editing enzyme complex, of which the catalytic subunit APOBEC-1 is not expressed in the liver of species without hepatic editing. To understand the molecular basis for liver-specific expression of APOBEC-1 and the editing of hepatic apo B mRNA, the expression pattern and genomic organization of the rat APOBEC-1 gene have been characterized. The rat APOBEC-1 gene contains 6 exons and 2 promoters with distinct activities. The expression of APOBEC-1 in the rat liver is the result of a promoter located upstream, with tissue-specific exon use and alternate splicing within the 5′-untranslated region of APOBEC-1 mRNA encoded by exon 2. In addition to the liver, this promoter also induces APOBEC-1 expression in the spleen, lung, kidney, heart, and skeletal muscle. The promoter located downstream belongs to a new class of TATA-less promoters and is responsible for the abundant expression of APOBEC-1 in the intestine. Mapping of the transcriptional start sites and deletion analysis of the promoter regions by using luciferase as the reporter gene have defined the regulatory elements of both promoters. The downstream, intestine-specific promoter contains a negative regulatory element between −1100 and −500, which appears to restrict its activity to the intestine. The upstream, liver-specific promoter of the rat APOBEC-1 gene induces APOBEC-1 expression and editing of apo B mRNA in human hepatoma HuH-7 and Hep G2 cells. Understanding the molecular basis for the liver-specific expression of APOBEC-1 in the rat promises new strategies to induce APOBEC-1 expression in the human liver for the reduction of atherogenic lipoprotein levels by hepatic apo B mRNA editing.
Leukocyte-Endothelium Interaction During the Early Stages of Hypercholesterolemia in the Rabbit
Authors: Scalia Rosario , Appel James Z. , Lefer Allan M.
Published: June 2011

Abstract—The early effects of hypercholesterolemia on leukocyte-endothelium interaction were studied in vivo in the rabbit mesenteric microcirculation. Rabbits fed a 0.5% high-cholesterol (HC) diet showed elevated plasma cholesterol levels during the 1 to 2 weeks of HC feeding (P<0.001 versus control diet–fed rabbits). Intravital microscopy of mesenteric venules revealed that leukocyte rolling had increased 10-fold (P<0.001 versus control-fed group) at the end of the first week of the HC diet, which was sustained after 2 weeks of HC feeding (P<0.001 versus control-fed rabbits). Firm adherence of leukocytes to the endothelium was moderately increased after a 1-week period of hypercholesterolemia (P<0.05) but increased by 12-fold at 2 weeks (P<0.001 versus control diet–fed andP<0.01 versus 1-week HC–fed rabbits). Upregulation of the endothelial cell adhesion molecules P-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 was observed immunohistochemically on the intestinal microvascular endothelium of HC-fed rabbits. P-selectin was maximally expressed within the first week of the HC diet and remained elevated during the second week of cholesterol feeding (P<0.01 versus control). In contrast, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were moderately upregulated at 1 week but were highly expressed after 2 weeks of the HC diet (P<0.05 andP<0.001 versus control, respectively). Basal release of NO from both mesenteric microvascular and aortic endothelium in cholesterol-fed rabbits was progressively reduced after 1 (P<0.05) and 2 (P<0.01) weeks. Our data suggest that enhanced leukocyte-endothelium interaction occurs in vivo in the rabbit microcirculation during the first 2 weeks of hypercholesterolemia. This phenomenon is associated with impaired basal NO release and progressive endothelial surface expression of endothelial cell adhesion molecules (ie, P-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1) in the microvasculature.
Conjugated Equine Estrogens Alone, but Not in Combination With Medroxyprogesterone Acetate, Inhibit Aortic Connective Tissue Remodeling After Plasma Lipid Lowering in Female Monkeys
Authors: Register Thomas C. , Adams Michael R. , Golden Deborah L. , Clarkson Thomas B.
Published: June 2011

Abstract—The objective of this study was to determine the arterial responses to plasma lipid lowering alone or in combination with (1) estrogen replacement therapy or (2) hormone replacement therapy in surgically postmenopausal female monkeys with preexisting atherosclerosis. Eighty-eight female cynomolgus macaques were ovariectomized, fed an atherogenic diet for 24 months, and then assigned by randomized stratification into 4 groups. One group (baseline, n=20) was necropsied at the end of the atherogenic diet period; the remaining 3 groups were fed a plasma lipid–lowering diet (regression) for 30 months. These regression groups were control (diet only), CEE (receiving conjugated equine estrogens alone), and CEE+MPA (receiving CEE and continuous medroxyprogesterone acetate). A previous report described coronary artery functional and histological results; the present report describes biochemical and histological results from the abdominal aorta. Aortic plaque size was not different between groups, similar to previous findings in the coronary arteries. Aortic cholesterol content (milligrams per gram lipid-free dry weight) was lower in the regression groups compared with baseline, both for free cholesterol (mean, control=19.1, CEE=15.7, CEE+MPA=14.4, and baseline=32.7;P<0.001) and for esterified cholesterol (mean, control=18.9, CEE=15.4, CEE+MPA=14.2, and baseline=58.7;P<0.001). This cholesterol efflux could lead to increased plaque stability without changing the physical size of the lesion. Alterations in aortic connective tissue composition were observed in the regression groups. When expressed as a percentage of the lipid-free tissue weight, the aortic elastin content of the control (mean=14.9) and the CEE+MPA (mean=14.0) groups was lower than that of the baseline group (mean=19.0), which was not different from that of the CEE group (mean=15.8). Aortic collagen content, as estimated by hydroxyproline content per milligram of lipid-free tissue, was higher in the control group (mean=67.4) and the CEE+MPA group (mean=66.1) than in the baseline group (mean=56.2;P<0.05). Collagen content of the CEE group (mean=58.9) was not different from that of the baseline group. When the regression groups were considered separately, the aortic collagen content of the CEE group was lower than that of the control group (P<0.05) and tended to be lower than that of the CEE+MPA group (P=0.10), suggesting that CEE therapy (but not CEE+MPA) inhibits potentially detrimental connective tissue alterations that accompany lesion regression. These results have implications for combinations of lipid-lowering and hormone replacement therapies in relation to vascular remodeling and abdominal aortic aneurysm development.
Antibody Titers Against Oxidized LDL Are Not Elevated in Patients With Familial Hypercholesterolemia
Authors: Hulthe Johannes , Wikstrand John , Lidell Aira , Wendelhag Inger , Hansson Göran K. , Wiklund Olov
Published: June 2011

Abstract
—Antibodies against oxidized low density lipoproteins (Ox-LDLs) have been proposed to be independent predictors of atherosclerosis development. The main aims of the current study were to (1) compare antibody titers to Ox-LDL in patients with heterozygous familial hypercholesterolemia (n=51) with those in matched controls (n=45) and (2) analyze whether the antibody titers were related to the extent of atherosclerosis, as assessed cross-sectionally and prospectively by ultrasonography in the 2 study groups. Antibody titers were determined with a solid-phase ELISA, and plates were coated with the antigens Ox-LDL or malondialdehyde-treated LDL (MDA-LDL) as well as with the postcoat only (5% dry milk powder). Antibody titers were expressed as absorbance [(value in patient serum minus that in postcoat) divided by (Internal Standard Serum minus postcoat)]. There were no significant differences in antibody titers against Ox-LDL or MDA-LDL between the group of patients with familial hypercholesterolemia and the controls. In cross-sectional comparisons, no significant associations were observed between the intima-media thickness of the carotid or femoral arteries and antibody titers against Ox-LDL or between plaque occurrence and these titers. Patients with a history of myocardial infarction had significantly lower IgM titers against Ox-LDL compared with patients without a history of myocardial infarction and with controls. In conclusion, mean values for antibody titers against Ox-LDL were not increased in the patient group compared with a healthy control group, and no positive, significant relationship was observed between antibody titers and the extent of atherosclerosis, as measured by ultrasound, in the carotid or femoral arteries. Taken together, these findings indicate that the relationship between the autoimmune response to Ox-LDL and the extent of atherosclerosis is more complex than previously anticipated.
The F
2
-Isoprostane 8-Epiprostaglandin F
2α
Increases Platelet Adhesion and Reduces the Antiadhesive and Antiaggregatory Effects of NO
Authors: Minuz Pietro , Andrioli Giuseppe , Degan Maurizio , Gaino Stefania , Ortolani Riccardo , Tommasoli Rosamaria , Zuliani Valeria , Lechi Alessandro , Lechi Clara
Published: June 2011

Abstract
—F
2
-isoprostanes are prostaglandin (PG) isomers produced in vivo through free radical–catalyzed peroxidation of arachidonic acid, which may affect platelet function. The current study investigated the effects of 8-epiprostaglandin F
2α
(8-epi-PGF
2α
) on critical events of platelet activation. A dose-dependent increase in platelet adhesion to fibrinogen- and plasma-coated microwells by 8-epi-PGF
2α
(1 to 1000 nmol/L) was observed when resting platelets (plasma from 1.3±0.2% to 5.5±0.2%, EC
50
of 48 nmol/L; fibrinogen from 3.3±0.3% to 6.4±0.2%, EC
50
of 35 nmol/L; mean±SEM, n=8,
P
<0.001) and thrombin-stimulated human platelets were used. The expression of the adhesion molecule glycoprotein IIb/IIIa was increased by 10 to 1000 nmol/L 8-epi-PGF
2α
in resting platelets (from 64.8±2.1% to 83.9±1.3%; n=5,
P
<0.01) and in stimulated platelets. The secretion of the glycoprotein GMP-140 increased only in the presence of both thrombin and 10 to 1000 nmol/L 8-epi-PGF
2α
(from 48.5±3.1% to 63.1±2.0%,
P
<0.05). The antiaggregatory effects of both the NO donor NOR-3 (basal, 21.4±4.6%; with 8-epi-PGF
2α
, 30.8±6.9%; n=14,
P
<0.05) and endothelial cells that release NO (basal, 18.5±4.6%; with 8-epi-PGF
2α
, 30.7±5.3%; n=15,
P
<0.001) were also reduced. All of these effects were prevented by the thromboxane receptor antagonist GR32191 but not affected by acetylsalicylic acid. An increase in free intracellular calcium concentration, measured with the use of fura 2, was observed with 8-epi-PGF
2α
. In conclusion, F
2
-isoprostanes may participate in oxidative injury by inducing platelet activation and by reducing the antiplatelet activity of NO: increased platelet adhesiveness and expression of the fibrinogen receptor are induced by nanomolar amounts of 8-epi-PG-F
2α
. Platelet secretion and aggregation can also be induced in the presence of platelet agonists.
C-Reactive Protein Frequently Colocalizes With the Terminal Complement Complex in the Intima of Early Atherosclerotic Lesions of Human Coronary Arteries
Authors: Torzewski Jan , Torzewski Michael , Bowyer David E. , Fröhlich Margit , Koenig Wolfgang , Waltenberger Johannes , Fitzsimmons Colin , Hombach Vinzenz
Published: June 2011

Abstract—There is increasing evidence that complement activation may play a role in atherogenesis. Complement proteins have been demonstrated to be present in early atherosclerotic lesions of animals and humans, and cholesterol-induced atherosclerotic lesion formation is reduced in complement-deficient animals. Potential complement activators in atherosclerotic lesions are now a subject matter of debate. C-reactive protein (CRP) is an acute-phase protein that is involved in inflammatory processes in numerous ways. It binds to lipoproteins and activates the complement system via the classic pathway. In this study we have investigated early atherosclerotic lesions of human coronary arteries by means of immunohistochemical staining. We demonstrate here that CRP deposits in the arterial wall in early atherosclerotic lesions with 2 predominant manifestations. First, there is a diffuse rather than a focal deposition in the deep fibroelastic layer and in the fibromuscular layer of the intima adjacent to the media. In this location, CRP frequently colocalizes with the terminal complement complex. Second, the majority of foam cells below the endothelium show positive staining for CRP. In this location, no colocalization with the terminal complement proteins can be observed. Our data suggest that CRP may promote atherosclerotic lesion formation by activating the complement system and being involved in foam cell formation.
Enhanced Upregulation of the Fcγ Receptor IIIa (CD16a) During In Vitro Differentiation of ApoE4/4 Monocytes
Authors: Stöhr Josef , Schindler Gisela , Rothe Gregor , Schmitz Gerd
Published: June 2011

Abstract—We recently reported a positive correlation of the pool size of lipopolysaccharide receptor (CD14)dimand Fcγ receptor IIIa (CD16a)+monocytes in peripheral blood to the apolipoprotein E4 (apoE4) phenotype and a negative correlation to high density lipoprotein (HDL) cholesterol levels (Arterioscler Thromb Vasc Biol.1996;16:1437–1447). In this study, the in vitro differentiation of mononuclear phagocytes derived from healthy blood donors homozygous for the E3/3 or the E4/4 phenotype was analyzed during 7 days of culture in serum-free medium supplemented with macrophage colony–stimulating factor (M-CSF). The CD16a expression, which indicates Fc receptor–dependent phagocytic activity, increased to a significantly higher level in apoE4/4 monocytes than in apoE3/3 cells. The costimulatory molecule CD40, which indicates antigen-presenting capacity, was upregulated more strongly in apoE3/3 monocytes compared with E4/4 cells, but the difference did not reach a significant level. The expression of differentiation-associated surface proteins (CD14, CD33, CD45) and adhesion molecules (CD11a, CD11b, CD11c, CD49d) was not significantly different between apoE3/3 and apoE4/4 monocytes. However, a significantly decreased intracellular apoE concentration and a reduced amount of secreted apoE were found in apoE4/4 monocytes during in vitro differentiation. No differences were found in the surface expression of the low density lipoprotein receptor–related protein (CD91) and the uptake of fluorescence labeled low density lipoprotein between apoE3/3 and apoE4/4 monocytes. These data indicate that the apoE4/4 phenotype significantly influences the M-CSF–dependent differentiation of monocytes toward a more CD16a-positive phagocytic phenotype.
Methylenetetrahydrofolate Reductase Gene Polymorphism and Ischemic Stroke in Japanese
Authors: Morita Hiroyuki , Kurihara Hiroki , Tsubaki Shin-ichi , Sugiyama Takao , Hamada Chikuma , Kurihara Yukiko , Shindo Takayuki , Oh-hashi Yoshio , Kitamura Kazuyuki , Yazaki Yoshio
Published: June 2011

Abstract
—Hyperhomocyst(e)inemia has been identified as an independent risk factor for atherosclerotic and thromboembolic diseases such as coronary artery disease, cerebral artery disease, and venous thrombosis. Recently, the alanine/valine (
A/V
) gene polymorphism of 5,10-methylenetetrahydrofolate reductase (MTHFR), one of the key enzymes that catalyzes the remethylation of homocysteine, was reported. The
VV
genotype is correlated with increased plasma homocyst(e)ine levels as a result of the reduced activity and increased thermolability of this enzyme. In this study, we examined the association between the
V
allele of the MTHFR gene and ischemic stroke in an elderly Japanese population. The diagnosis of cerebral infarction of all study patients was confirmed by CT of the brain. The MTHFR genotype was analyzed by polymerase chain reaction followed by
Hin
fI digestion. In 256 stroke patients and 325 control subjects, the frequencies of the
V
allele were 0.45 and 0.32, respectively. The odds ratios and 95% confidence intervals adjusted for the other risk factors were, respectively, 1.51 (1.02 to 2.23) for the
AV
genotype and 3.35 (1.94 to 5.77) for the
VV
genotype compared with the
AA
genotype. Both of these effects were statistically significant (
P
=0.041 and
P
<0.001, respectively). In patients with multiple infarcts in particular, the allele frequency of the
V
mutation was 0.56, and the association between the
V
allele and stroke was highly significant. Plasma homocyst(e)ine levels were significantly higher in patients with the
VV
genotype than in patients with the
AA
or
AV
genotype, especially those with low plasma folate levels. The
V
allele of the MTHFR gene was significantly associated with cerebral infarction in an elderly Japanese population in a codominant manner. The
VV
genotype may contribute to risk for ischemic stroke through a predisposition to increased plasma homocyst(e)ine levels, and dietary folate supplementation may be of benefit, particularly to patients with this genotype.
Expression of Interleukin-6 in Atherosclerotic Lesions of Male ApoE-Knockout Mice
Authors: Sukovich Drew A. , Kauser Katalin , Shirley Francine D. , DelVecchio Virginia , Halks-Miller Meredith , Rubanyi Gabor M.
Published: June 2011

Abstract—Increased levels of interleukin-6 (IL-6) have been proposed to contribute to a number of pathological disorders, including osteoporosis and Alzheimer’s disease. In human atherosclerotic lesions, IL-6 protein and mRNA have been detected, although the role of IL-6 in plaque formation is unknown. We have examined the expression pattern of IL-6 mRNA and secreted protein in male apolipoprotein E–knockout (apoE-KO) mice aortas. Furthermore, we have evaluated the effects of 17β-estradiol (E2), a vasculoprotective sex steroid hormone, on the secretion of this inflammatory cytokine from isolated male apoE-KO mice aortas. The expression of IL-6 mRNA was detected by reverse transcription–polymerase chain reaction in the apoE-KO mouse aortas but not in the aortas of age-matched control mice. Similarly, the secretion of IL-6 protein from isolated apoE-KO aortic segments was significantly greater than that from aortas of age-matched control animals. The secretion of IL-6 from isolated aortic rings of apoE-KO mice ranging in age from 6 to 48 weeks showed a significant, positive correlation with percent lesion area measured in the same tissue. Immunohistochemical staining of apoE-KO mouse aortic tissue sections demonstrated colocalization of IL-6 expression with macrophages. Treatment of male apoE-KO mice with E2 for 3 weeks resulted in a statistically significant 50% reduction in IL-6 secretion from ex vivo aortic tissue segments. There was no significant change in total serum cholesterol and triglyceride levels in the E2-treated group compared with placebo-treated controls. These data demonstrate that (1) IL-6 mRNA and protein are expressed in the atherosclerotic plaques of apoE-KO mice aortas and (2) IL-6 production is suppressed by E2 treatment, which may contribute to the antiatherosclerotic effects of E2 in the apoE-KO mouse model of atherosclerosis.
Administration of n-3 Fatty Acids in the Diets of Rats or Directly to Hepatocyte Cultures Results in Different Effects on Hepatocellular ApoB Metabolism and Secretion
Authors: Brown Anna-Marie , Castle Jenni , Hebbachi Abdel-Malek , Gibbons Geoffrey F.
Published: June 2011

Abstract
—Hepatocytes derived either from rats fed a diet enriched in n-3 fatty acids or from rats fed a low-fat diet and cultured with an n-3 fatty acid (eicosapentaenoic acid, EPA) in vitro were used to distinguish between the dietary effects and the direct effects of n-3 fatty acids on hepatocellular apolipoprotein (apo) B metabolism and secretion. ApoB-48 and apoB-100 synthesis, degradation, and secretion as large (
d
<1.006) and small (
d
>1.006) particles were determined after a pulse label with [
35
S]methionine. These effects were compared with changes in triacylglycerol (TAG) synthesis and secretion and with changes in de novo fatty acid synthesis (using
3
H
2
O incorporation) under identical conditions. When n-3 fatty acid was given via the dietary route, apoB-48 very low density lipoprotein (VLDL) secretion was inhibited, but there was no effect on the secretion of apoB-100 VLDL. There was no effect on the secretion of either apoB-48 or apoB-100 as small, dense particles (
d
>1.006). Cellular TAG synthesis was significantly inhibited under these conditions, and fatty acid synthesis de novo was inhibited by 80%. By contrast, after direct addition of EPA to hepatocytes from normal rats, the secretion of both apoB-48 and apoB-100 VLDL was suppressed. The secretion of apoB-48, but not of apoB-100, as dense particles was also inhibited. However, there was little or no effect on TAG synthesis nor on fatty acid synthesis de novo. In addition, whereas dietary administration of n-3 fatty acid gave rise to decreased net synthesis and degradation of apoB-48, direct administration in vitro resulted in increased degradation with no effect on net synthesis. We conclude that the effects of n-3 fatty acids on hepatic lipid and apoB metabolism differ according to whether they are administered in vivo, via the dietary route, or in vitro, via direct addition to hepatocyte cultures.