bluuebunny/crossref_metadata_2025 huggingface dataset:
Interferon Gamma Binds to Extracellular Matrix Chondroitin-Sulfate Proteoglycans, Thus Enhancing Its Cellular Response
Authors: Camejo Eva Hurt , Rosengren Birgitta , Camejo Germán , Sartipy Peter , Fager Gunnar , Bondjers Göran
Published: June 2011

AbstractThe amino acid sequence of interferon gamma (IFN-γ) has basic amino acid clusters similar to the heparin-binding consensus sequences found in other proteins that bind to proteoglycans (PGs). We investigated whether recombinant human IFN-γ could bind to extracellular matrix (ECM) PGs secreted by human arterial smooth muscle cells (HASMCs) in vitro and whether the interaction affected the cellular response to IFN-γ. As an in vitro model of ECM we used the basement membrane from HASMCs in culture. The binding of125I-IFN-γ to ECM was reduced significantly by pretreatment of ECM with chondroitinase ABC, an enzyme that degrades chondroitin-sulfate glycosaminoglycans. IFN-γ binding to ECM was reduced by increasing concentrations of chondroitin-6-sulfate.125I-IFN-γ (0.05 to 2 ng/mL) binding data indicated an apparentKdof 2×10−11mol/L and a maximum binding of 1.6×106IFN-γ molecules bound per square millimeter of ECM. Experiments with synthetic peptides suggested that residues 127 through 135 (AKTGKRKRS) are involved in the binding. The binding to chondroitin-sulfate PGs was confirmed by affinity chromatography of isolated [35S]chondroitin-sulfate PGs from ECM and cell-culture medium on immobilized IFN-γ. The binding was abolished by treatment with chondroitinase ABC. ECM-bound IFN-γ was more effective in inducing the expression of class II major histocompatibility antigens such as HLA-DR in HASMCs and human arterial endothelial cells than soluble IFN-γ. These results suggest a role for chondroitin-sulfate PGs in immobilizing IFN-γ in the ECM compartment and enhancing the cellular response to IFN-γ.
Transfer of Lipoprotein(a) and LDL Into Aortic Intima in Normal and in Cholesterol-Fed Rabbits
Authors: Nielsen Lars B. , Nordestgaard Børge G. , Stender Steen , Niendorf Axel , Kjeldsen Knud
Published: June 2011

Abstract
To study the relative atherogenic potential of lipoprotein(a) [Lp(a)], the transfer of Lp(a) and LDL into the arterial wall was compared in normal rabbits, cholesterol-fed rabbits, and normal rabbits in which the plasma concentration of Lp(a) before injection of labeled lipoproteins was increased by an intravenous mass injection of 45 mg Lp(a). Aorta was removed either 60 minutes or 180 minutes after intravenous injection of a mixed preparation of human
125
I-Lp(a) and
131
I-LDL; intimal clearance was calculated as radioactivity in aortic intima/inner media divided by the average concentration of the appropriate radioactivity in plasma and by the length of the exposure time. The intimal clearance of labeled Lp(a) and LDL in the aortic arch after 60 minutes of exposure was 87±9 and 47±7 nL · cm
−2
· h
−1
(n=9) in normal rabbits and 82±14 and 62±10 nL · cm
−2
· h
−1
(n=10) in cholesterol-fed rabbits; after 180 minutes of exposure, the intimal clearance of labeled Lp(a) and LDL was 62±14 and 84±21 nL · cm
−2
· h
−1
(n=6) and 30±6 and 47±12 nL · cm
−2
· h
−1
(n=4) in cholesterol-fed and Lp(a)-injected rabbits, respectively. Linear regression analysis showed positive associations between intimal clearance of the two lipoproteins in all four groups of rabbits in the aortic arch, the thoracic aorta, and the abdominal aorta. Aortic immunoreactivity of human apolipoprotein(a) was detected in the intima in association with fatty streak lesions, predominantly within the cytoplasm of foam cells. These results suggest that Lp(a) is transferred into the aortic intima by a mechanism similar to that for LDL and that Lp(a) can be taken up by intimal foam cells; however, Lp(a) and LDL may be metabolized differently upon entrance into the arterial wall.
Proliferating Arterial Smooth Muscle Cells After Balloon Injury Express TNF-α but Not Interleukin-1 or Basic Fibroblast Growth Factor
Authors: Tanaka Hiroyuki , Sukhova Galina , Schwartz David , Libby Peter
Published: June 2011

AbstractWe have recently reported that balloon withdrawal injury to rabbit abdominal aortas induces sustained activation indicated by the expression of certain adhesion molecules such as vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in regenerating endothelial cells and/or proliferating smooth muscle cells (SMCs). Local cytokine signaling may contribute to ongoing modulation of cellular functions and proliferation of intimal SMCs after acute vascular injury. We therefore studied the expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), proinflammatory and SMC growth–promoting cytokines, and basic fibroblast growth factor (bFGF) in SMCs of rabbit aorta at 2 (n=4), 5 (n=4), and 10 days (n=6) after balloon injury. All animals were given bromodeoxyuridine (BrdU, 10 mg/kg per day) continuously to label proliferating SMCs. Frozen cross sections of injured vessels at each time point after balloon injury were examined by immunoperoxidase staining with monoclonal antibodies. As early as 2 days after injury, before intimal thickening begins, foci of medial SMCs expressed TNF-α, but not all TNF-α–positive medial SMCs had incorporated BrdU, suggesting that TNF-α expression by medial SMCs may precede their proliferation. At 5 days, TNF-α–bearing and BrdU-labeled medial SMCs increased in number. At 10 days after injury, when uniform intimal thickening occurred, almost all neointimal SMCs and foci of medial SMCs labeled with BrdU. Most of the BrdU-positive (proliferating) SMCs expressed immunoreactive TNF-α. Reverse transcription polymerase chain reaction showed increased TNF-α mRNA at 10 days after ballooning in the injured portion of the aorta. In contrast, regions of SMC proliferation showed inconsistent IL-1β expression, and bFGF, abundant in normal rabbit arteries, was not detected in areas of SMC replication. These data indicate that replication of arterial SMCs after balloon injury occurs in regions of TNF-α but not IL-1β expression and correlates inversely with the presence of bFGF. These results indicate that SMC-derived TNF-α serves as a marker of modulated SMC phenotype after acute vascular injury and may contribute to local cellular activation and proliferation of SMCs at sites of arterial injury.
Optimal Antagonism of GPIIb/IIIa Favors Platelet Adhesion by Inhibiting Thrombus Growth
Authors: André Patrick , Arbeille Brigitte , Drouet Valérie , Hainaud Patricia , Bal dit Sollier Claire , Caen Jacques P. , Drouet Ludovic O.
Published: June 2011

AbstractTo evaluate the involvement of the glycoprotein (GP) IIb/IIIa–dependent process in platelet deposition and thrombus growth on capillaries coated with human type III collagen, the effects of incremental doses of Lamifiban, a potent specific synthetic GPIIb/IIIa antagonist, were studied in ex vivo capillary perfusion chambers using guinea pig blood. In this model, nonanticoagulated blood was perfused for 4.5 minutes at three shear rates: 100, 650, and 1600 s−1. Platelet deposition was quantified by computer-assisted morphometry and expressed as platelet adhesion (percentage of capillary surface covered with spread and contact platelets and platelets implicated in thrombus), mean thrombus height, and total thrombus cross-sectional area. In control untreated guinea pigs, platelet adhesion and thrombus height were 63% and 2.5 μm at 100 s−1, 60.5% and 13.8 μm at 650 s−1, and 45% and 28.1 μm at 1600 s−1, respectively. At 100 s−1, Lamifiban had no effect on platelet deposition at any of the three doses administered to the guinea pigs (0.3, 1, and 3 mg/kg). At 0.3 mg/kg and shear rates of 650 and 1600 s−1, Lamifiban had no effect on platelet adhesion or thrombus size, but at 1 and 3 mg/kg and shear rates of 650 and 1600 s−1, it significantly reduced thrombus size. At 1600 s−1, 1 mg/kg Lamifiban significantly increased platelet adhesion from 45% to 62.5%, whereas at 3 mg/kg it induced a significant overall decrease from 45% to 25% and qualitatively increased the ratio of contact to spread platelets. These data suggest that at high shear rates, GPIIb/IIIa participates in platelet spreading and that there is a balance between platelet involvement in adhesion to the thrombogenic surface and the growth of the already formed thrombus. This indicates that important clinical implications of an optimal therapeutic degree of GPIIb/IIIa antagonism could be expected.
Monounsaturated Fatty Acid–Enriched Diet Decreases Plasma Plasminogen Activator Inhibitor Type 1
Authors: Lopez-Segura F. , Velasco F. , Lopez-Miranda J. , Castro P. , Lopez-Pedrera R. , Blanco A. , Jimenez-Pereperez J. , Torres A. , Trujillo J. , Ordovas J.M. , Pérez-Jiménez F.
Published: June 2011

Abstract
An increase in levels of plasma plasminogen activator inhibitor type 1 (PAI-1) is one of the main hemostatic alterations in patients with coronary heart disease. Despite growing interest in the fibrinolytic system, few studies have been undertaken to determine the effect exerted on it by the different dietary fatty acids. We investigated the effect of a monounsaturated fat (MUFA)–rich diet in comparison with a low-fat diet (National Cholesterol Education Program step 1 diet) (NCEP-1) on factors involved in blood coagulation and fibrinolysis. We also determined the effect of dietary cholesterol on these blood parameters. Twenty-one young, male, healthy volunteers followed two low-fat/high-carbohydrate diets (<30% fat, <10% saturated fat, 14% MUFA) for 24 days each, with 115 or 280 mg of cholesterol per 1000 kcal per day, and two oleic acid–enriched diets (38% fat, 24% MUFA) with the same dietary cholesterol as the low-fat/high-carbohydrate diets. Plasma levels of fibrinogen, thrombin-antithrombin complexes, prothrombin fragments 1+2, plasminogen, α
2
antiplasmin, and tissue plasminogen activator were not significantly different among the experimental diets used in this study. Consumption of the diet rich in MUFA resulted in a significant decrease in both PAI-1 plasma activity (
P
<.005) and antigenic PAI-1 (
P
<.04) compared with the carbohydrate-rich diet (NCEP-1). The addition of dietary cholesterol to each of these diets did not result in any significant additional effect. Changes in insulin levels and PAI-1 activity were positively correlated (
r
=.425;
P
<.02). In conclusion, consumption of diets rich in MUFAs decreases PAI-1 plasma activity, which is accompanied by a parallel decrease in plasma insulin levels.
Angiotensin II–Modified LDL Is Taken Up by Macrophages Via the Scavenger Receptor, Leading to Cellular Cholesterol Accumulation
Authors: Keidar Shlomo , Kaplan Marielle , Aviram Michael
Published: June 2011

Abstract
The incidence of myocardial infarction is significantly higher in hypertensive patients with increased plasma concentration of angiotensin (Ang) II. Ang II was shown to bind to LDL in vitro, and in the present study we showed its binding to LDL in vivo. Ang II (10
−7
mol/L) was incubated with LDL for 3 hours at 37°C, followed by reseparation of the modified lipoprotein (Ang II–LDL) and its incubation with J-774 A.1 macrophages. Binding of Ang II to LDL significantly increased the lipoprotein protein degradation (by 25%) and its cell association (by 75%) compared with nontreated LDL. Unlike Ang II–LDL, both Ang I–LDL and Ang III–LDL were taken up by macrophages similar to native LDL. The lipid composition and size of Ang II–LDL were similar to those of native LDL, and it was not aggregated. Ang II–LDL was not oxidized, as the contents of malondialdehyde and peroxides were not different from those found in native LDL. On heparin-Sepharose column chromatography, Ang II–LDL was eluted in the void volume, like acetylated LDL (Ac-LDL) and unlike native LDL, which binds to heparin. The cellular degradation of Ang II-
125
I–labeled LDL by J-774 A.1 macrophages was studied in the presence of a 50-fold excess of nonlabeled native LDL, Ang II–LDL, Ac-LDL, or oxidized LDL (Ox-LDL). Whereas native LDL had no effect on the degradation of Ang II-
125
I–LDL by the macrophages, Ac-LDL, Ox-LDL, and Ang II–LDL reduced the cellular uptake of the lipoprotein by 77%, 82%, and 87%, respectively. Similarly, fucoidin but not free Ang II reduced macrophage degradation of the labeled Ang II–LDL. We conclude that Ang II can modify LDL to a form that is not oxidized or aggregated but is still taken up at an enhanced rate by macrophages via the scavenger receptor.
Dietary Cholesterol Feeding Suppresses Human Cholesterol Synthesis Measured by Deuterium Incorporation and Urinary Mevalonic Acid Levels
Authors: Jones Peter J.H. , Pappu Anuradha S. , Hatcher Lauren , Li Zi-Chi , Illingworth D. Roger , Connor William E.
Published: June 2011

The objective of this study was to measure the response of cholesterol biosynthesis in subjects to three different amounts of dietary cholesterol: 50 (low), 350 (medium), and 650 (high) mg cholesterol per 2800 kcal. Individuals with low (n=7), normal (n=12), and elevated (n=11) plasma cholesterol concentrations consumed in random order solid-food test diets (15%, 55%, and 30% of energy as protein, carbohydrate, and fat, respectively) at each dietary cholesterol level. The three diets were consumed for 4 weeks each, and each dietary phase was separated by a 4-week washout period. During the final week of each diet, 0.7 g D
2
O was given per kilogram of body water and deuterium incorporation into the erythrocyte cholesterol pool was measured for 24 hours. Urinary mevalonate levels were also determined in samples obtained during two consecutive 24-hour periods. Both techniques provided measurements of whole-body cholesterol biosynthesis. In all subjects the cholesterol synthesis rate as measured by deuterium incorporation was significantly lower (
P
<.05) after the transition from low- to medium- and low- to high-cholesterol diets. Urinary mevalonate excretion decreased after the change from the medium- to high- (
P
<.05) and low- to high- (
P
<.01) cholesterol diets. Although correspondence between the two methods was poor, they both indicated some suppression of cholesterol synthesis by dietary cholesterol. The response of cholesterogenesis to different amounts of dietary cholesterol was related to the rate of synthesis under depressed conditions of the low-cholesterol diet. These findings indicate modest downregulation of synthesis in response to dietary cholesterol in humans, independent of plasma cholesterol levels.
Autoantibodies Against Oxidized LDL Do Not Predict Atherosclerotic Vascular Disease in Non–Insulin-Dependent Diabetes Mellitus
Authors: Uusitupa Matti I.J. , Niskanen Leo , Luoma Jukka , Vilja Pekka , Mercuri Michele , Rauramaa Rainer , Ylä-Herttuala Seppo
Published: June 2011

Accelerated atherosclerosis in diabetes has been suggested as being due to an enhanced oxidative modification of LDL. We hypothesized that the titers of autoantibodies against oxidized LDL (oxLDL) may be increased in patients with non–insulin-dependent diabetes mellitus (NIDDM) and that they may contribute to various manifestations of atherosclerosis among such patients. In a 10-year follow-up study of 91 newly diagnosed NIDDM patients and 82 nondiabetic control subjects, autoantibodies against oxLDL (expressed as the ratio of autoantibodies against oxLDL and native LDL) were measured at baseline and after 10 years. Quantitative ultrasonography to examine the intimal-medial thickness of the common carotid artery (a morphological index of arterial wall injury) and carotid bifurcation was performed at the 10-year examination. The relationship of autoantibodies against oxLDL to the occurrence of cardiovascular death, fatal and nonfatal myocardial infarction, stroke, and any cardiovascular event as well as to the intimal-medial thickness of the common carotid artery and carotid bifurcation was evaluated. Associations between these autoantibodies and metabolic variables (fasting glucose, glycosylated hemoglobin, insulin, and serum lipids) in NIDDM patients were also examined. Autoantibodies against oxLDL did not differ between NIDDM and control subjects (NIDDM: baseline, 1.63 and 0.61 to 23.6; 10-year examination, 1.64 and 0.06 to 59.0; control group: baseline, 1.84 and 0.13 to 36.0; 10-year examination, 1.50 and 0.25 to 8.29; median and range,
P
=.62, baseline;
P
=.45, 10 year). In both groups, the titers of these autoantibodies measured at baseline and after 10 years significantly correlated with each other (
r
=.63 for the diabetic and
r
=.51 for the control group, respectively,
P
<.001 for each). The frequency of all cardiovascular events was markedly higher in the NIDDM group than in the control group, but autoantibodies against oxLDL had no significant association with any of these events, including cardiovascular mortality. At the 10-year examination the intimal-medial thicknesses of the common carotid artery (1.24±0.36 versus 1.06±0.30 mm,
P
=.002) and carotid bifurcation (2.11±0.73 versus 1.77±0.82 mm,
P
=.01) were greater in NIDDM patients than in control subjects, but autoantibodies did not show any association with the intimal-medial thicknesses in either the diabetic or control groups. Autoantibodies against oxLDL indicate the presence of oxidatively modified LDL in vivo, but their titers in the serum do not seem to associate with the excess cardiovascular mortality, morbidity, or intimal-medial thickness of the carotid artery.
Contrasting Effects of Plasminogen Activators, Urokinase Receptor, and LDL Receptor–Related Protein on Smooth Muscle Cell Migration and Invasion
Authors: Okada S. Steve , Grobmyer Stephen R. , Barnathan Elliot S.
Published: June 2011

Smooth muscle cell (SMC) migration is an early response to vascular injury and contributes to the development of intimal thickening. Upregulation of several components of the plasminogen activator (PA) system has been documented after vascular injury. Utilizing a Transwell filter assay system and human umbilical vein SMCs, we sought to define the role of four different PA system components on SMC migration and matrix invasion: (1) PAs, (2) plasmin, (3) PA receptors, and (4) PA clearance receptors (ie, low density lipoprotein receptor–related protein [LRP]). Addition of active two-chain urokinase-type PA (UPA) stimulated random migration (192±30% of control, 0.36 nmol/L,
P
<.001). The stimulation was inhibited by pretreatment with diisopropylfluorophosphate, PA inhibitor type 1 (PAI-1), or aprotinin, a plasmin inhibitor. Augmented migration was also observed with either low-molecular-weight UPA or the amino terminal fragment of UPA (ATF), with the effects being additive. Stimulation by ATF alone, however, was not inhibited by aprotinin. The stimulatory effect was not specific for UPA, in that tissue-type PA (TPA) also increased migration (169±9% of control, 10 nmol/L,
P
<.001); the augmentation was inhibited by pretreatment with DFP, PAI-1, or aprotinin and was additive to the UPA effect. Antibodies to the UPA receptor but not 5′-nucleotidase (another glycosylphosphatidylinositol-anchored cell surface protein) inhibited baseline and UPA-stimulated migration. Similarly, both UPA and TPA stimulated invasion of a collagen gel; this augmentation was inhibited by aprotinin, whereas antibodies to the UPA receptor reduced baseline invasion. Finally, we tested whether inhibition of LRP function, which mediates internalization of PA/inhibitor complexes, affected either process. Both antibodies to LRP and recombinant receptor associated protein, a known inhibitor of ligand binding to the LRP, significantly inhibited migration but did not affect collagen gel invasion. These data demonstrate the ability of several components of the PA system to modulate SMC migration and invasion in vitro via plasmin-dependent and -independent mechanisms.
Thrombin Inhibition by Antithrombin III on the Subendothelium Is Explained by the Isoform ATβ
Authors: Frebelius Siw , Isaksson Sven , Swedenborg Jesper
Published: June 2011

Balloon injury of the rabbit aorta results in thrombin coagulant activity on the injured vessel wall that causes fibrin formation. The anticoagulant activity of both the intact and injured vessel wall has been partly explained by glycosaminoglycans with heparin-like activity that augment the activity of antithrombin III (AT). AT exists in two isoforms, α and β. ATβ, which constitutes only 5% to 10% of AT in plasma, lacks one carbohydrate side chain, has higher affinity for glycosaminoglycans, and associates more readily with the subendothelium. This study evaluated whether AT can inhibit thrombin on the injured vessel wall and, if so, whether one of the isoforms is more effective then the other. The two isoforms were isolated from human plasma by heparin-Sepharose chromatography, and the purity was investigated by isoelectric focusing and crossed immunoelectrophoresis. Rabbits were subjected to balloon injury of the aorta; 3 hours after injury the aorta was excised. Thrombin coagulant activity on the aorta was measured by exposure to fibrinogen and thereafter by measuring the generation of fibrinopeptide A. Injured animals were treated with AT, ATα, or ATβ and were compared with control animals. AT was demonstrated on the injured vessel wall by using an immunohistochemical method. Animals receiving crude AT had significantly lower amounts of thrombin coagulant activity on the injured aortic wall than control animals, but ATα at a comparable dose had no effect. ATβ was given in the same dose as crude AT and also at a dose (10%) proportional to its presence in plasma. Animals receiving ATβ had significantly lower values of thrombin on the injured aortic wall than control animals. We conclude that the inhibitory effect of AT on thrombin coagulant activity on the injured vessel wall is explained by its ATβ content.
Transforming Growth Factor-β1 Expression and Myofibroblast Formation During Arterial Repair
Authors: Shi Yi , O'Brien James E. , Fard Ali , Zalewski Andrew
Published: June 2011

Transforming growth factor-β1 (TGF-β1) plays a central role in tissue repair owing to its modulating effects on cell growth and the synthesis of extracellular matrix. We have previously shown that adventitial fibroblasts differentiate to myofibroblasts after endoluminal injury, thereby contributing to arterial remodeling. Since TGF-β1 exerts several biologic actions attributed to myofibroblasts, we examined its role in myofibroblast formation in a porcine model of balloon overstretch coronary artery injury. TGF-β1 transcripts were induced in numerous adventitial cells 2 days after injury (47±10%,
P
<.001 versus control). These cells displayed no smooth muscle (SM) markers, ie, α-SM actin or desmin, which suggested their fibroblastic origin. This was further corroborated by the rare presence of macrophages in the injured adventitia (3±1%). At 7 to 8 days, most TGF-β1–expressing cells demonstrated α-SM actin immunoreactivity. Their myofibroblast phenotype was confirmed by electron microscopy, which revealed microfilaments (stress fibers) and a well-developed rough endoplasmic reticulum. The distribution of TGF-β1 transcripts by in situ hybridization was paralleled by the immunolocalization of intracellular and extracellular TGF-β1 epitopes. At later times (>14 days after injury), the decrease in TGF-β1 coincided with the disappearance of adventitial myofibroblasts, whereas the neointima exhibited longer TGF-β1 expression. In conclusion temporal and spatial relationships between TGF-β1 and myofibroblast formation suggest an important role for autocrine TGF-β1 in the phenotypic modulation of vascular fibroblasts. Induction of TGF-β1 expression may provide a differentiation signal for adventitial fibroblasts to become myofibroblasts, which affect arterial remodeling via their mechanical and synthetic properties.
In Vivo Demonstration in Humans That Large Postprandial Triglyceride-Rich Lipoproteins Activate Coagulation Factor VII Through the Intrinsic Coagulation Pathway
Authors: Silveira Angela , Karpe Fredrik , Johnsson Hans , Bauer Kenneth A. , Hamsten Anders
Published: June 2011

In vitro studies in purified plasma systems have suggested that triglyceride-rich lipoproteins such as chylomicrons, very low density lipoproteins, and their remnants promote activation of factor VII through activated factor XII (XIIa) and the intrinsic coagulation pathway. We specifically examined the roles of factors XII, XI, and IX in activation of factor VII during alimentary lipemia in vivo in humans and addressed the issue of whether generation of activated factor VII (VIIa) is accompanied by increased thrombin production. For this purpose XIIa, factor IX activation peptide (IXP), VIIa, prothrombin fragment 1+2 (F
1+2
), and thrombin-antithrombin complex (TAT) were determined in plasma samples taken before and 3, 6, and 9 hours after intake of a mixed meal type of oral fat load in 24 healthy men. The VIIa response to fat intake was also determined in 7 patients with single coagulation–factor deficiency, of whom 2 were deficient in factor XII, 2 in factor XI, and 3 in factor IX. Postprandial activation of factors IX and VII occurred in the healthy individuals, whereas the plasma levels of XIIa did not change in response to the test meal. Of note, plasma concentrations of F
1+2
were unaltered during alimentary lipemia, and TAT levels showed a small decrease (
P
<.05) in the 3-hour sample compared with the fasting level, indicating that thrombin generation is not stimulated in the postprandial state, despite the generation of activated factor IX (IXa) and VIIa. Factor VIIa increased in the postprandial period in the 2 factor XII–deficient patients who underwent the oral fat tolerance test but appeared to remain unchanged in the factor XI– and factor IX–deficient patients. Therefore, the current concept that activation of factor XII plays a pivotal role in initiating the sequence of events linking postprandial lipemia to activation of factor VII is contradicted by the present study. Whether activation of factor XI by triglyceride-rich lipoproteins initiates these reactions needs to be demonstrated in future studies.
Distribution and Correlates of Lipids and Lipoproteins in Elderly Japanese-American Men
Authors: Burchfiel Cecil M. , Abbott Robert D. , Sharp Dan S. , Curb J. David , Rodriguez Beatriz L. , Yano Katsuhiko
Published: June 2011

Adverse lipid and lipoprotein levels are clearly linked with increased risk of cardiovascular disease in middle age, but evidence in elderly and minority populations is less certain. In this study the distribution and correlates of lipids and lipoproteins were evaluated cross-sectionally in 3044 elderly (71 to 93 years) Japanese-American men from the Honolulu Heart Program who were recently reexamined (1991 to 1993). Mean±SD lipid concentrations were 189±33 mg/dL for total cholesterol, 51±13 mg/dL for HDL cholesterol, 109±31 mg/dL for LDL cholesterol, and 147±89 mg/dL for triglycerides. Prevalence of dyslipidemic patterns was relatively infrequent (total cholesterol ≥240 mg/dL: 6.7%; HDL cholesterol <35 mg/dL: 6.4%; LDL cholesterol ≥160 mg/dL: 5.5%; triglycerides ≥200 mg/dL: 18.7%), while prevalence of desirable total (<200 mg/dL) and HDL cholesterol (≥60 mg/dL) concentrations was more common (62.7% and 23.7%, respectively). Mean levels of total cholesterol, LDL cholesterol, and triglyceride decreased significantly with increasing age (
P
<.001), while mean HDL cholesterol level increased slightly (
P
<.05). After univariate analyses of potential correlates, multiple linear regression models were used to identify variables independently associated with each of the lipids. After adjustment for other variables, levels of fibrinogen and hematocrit were positively associated and insulin, white blood cell count, and use of diabetic medication were negatively associated with total cholesterol. Correlates for LDL cholesterol were similar but also included vital capacity (positive relation) and alcohol (negative relation). Heart rate, physical activity, alcohol, and hematocrit were positively associated with HDL cholesterol; body mass index, subscapular skinfold thickness, glucose, fibrinogen, white blood cell count, and hypertension were negatively associated. Factors associated with triglycerides tended to be similar, yet the direction of relations was reversed. Age-adjusted total cholesterol levels were significantly lower in men who had coronary surgery, thromboembolic stroke, and hemorrhagic stroke but were higher in those with peripheral vascular disease. Lower HDL cholesterol levels were found in men with prevalent angina, angioplasty, definite myocardial infarction, thromboembolic stroke, and peripheral vascular disease. LDL cholesterol and triglycerides showed fewer significant relations with these conditions. Findings indicate that elderly Japanese-American men have a favorable lipid profile, except for elevated triglyceride levels, relative to levels in other populations of older Americans and that a number of cardiovascular risk factors and diseases are strongly associated with lipids in elderly men. These analyses also identify several modifiable factors that may favorably influence lipid and lipoprotein levels in the elderly.
Selective Resistance of LDL Core Lipids to Iron-Mediated Oxidation
Authors: Tribble Diane L. , Chu Berbie M. , Levine Gerri A. , Krauss Ronald M. , Gong Elaine L.
Published: June 2011

Although the nature and consequences of oxidative changes in the chemical constituents of low density lipoproteins (LDLs) have been extensively examined, the physical dynamics of LDL oxidation and the influence of physical organization on the biological effects of oxidized LDLs have remained relatively unexplored. To address these issues, in the present studies we monitored surface- and core-specific peroxidative stress relative to temporal changes in conjugated dienes (CDs), particle charge (an index of oxidative protein modification), and LDL-macrophage interactions. Peroxidative stress in LDL surface and core compartments was evaluated with the site-specific, oxidation-labile fluorescent probes parinaric acid (PnA) and PnA cholesteryl ester (PnCE), respectively. When oxidation was initiated by Cu
2+
, oxidative loss of the core probe (PnCE) closely followed that of the surface probe (PnA), as indicated by the time to 50% probe depletion (t
1/2
; 15.5±7.8 and 30.4±12 minutes for PnA and PnCE, respectively). Both probes were more resistant in LDL exposed to Fe
3+
(t
1/2
, 53.2±8.1 and 346.7±155.4 minutes), although core probe resistance was much greater with this oxidant (PnCE t
1/2
/PnA t
1/2,
5.8 vs 2.0 for Cu
2+
). Despite differences in the rate and extent of oxidative changes in Cu
2+
- versus Fe
3+
-exposed LDLs, PnCE loss occurred in close correspondence with CD formation and appeared to precede changes in particle charge under both conditions. Exposure of LDLs to hemin, a lipophilic Fe
3+
-containing porphyrin that becomes incorporated into the LDL particle, resulted in rapid loss of PnCE and simultaneous changes in particle charge, even at concentrations that yielded increases in CDs and thiobarbituric acid–reactive substances similar to those obtained with free Fe
3+
. These results suggest that oxidation of the LDL hydrophobic core occurs in conjunction with accelerated formation of CDs and may be essential for LDL protein modification. In accordance with the known effects of oxidative protein modifications on LDL receptor recognition, exposure of LDLs to Cu
2+
and hemin but not Fe
3+
produced particles that were readily processed by macrophages. Thus, the physical site of oxidative injury appears to be a critical determinant of the chemical and biological properties of LDLs, particularly when oxidized by Fe
3+
.
Autocrine Induction of DNA Synthesis by Mechanical Injury of Cultured Smooth Muscle Cells
Authors: Calara Federico , Ameli Sean , Hultgårdh-Nilsson Anna , Cercek Bojan , Kupfer Joel , Hedin Ulf , Forrester James , Shah Prediman K. , Nilsson Jan
Published: June 2011

Abstract
To determine whether replication of arterial smooth muscle cells (SMCs) in response to mechanical injury would occur in the absence of serum and other cells, we created an in vitro model in which confluent, growth-arrested cultures of rat SMCs were injured by gentle pressure of a soft plastic tube and then kept in serum-free medium for up to 4 days. Replication of SMCs in and around the injury, as measured by tritiated thymidine incorporation, was noted within 24 hours and peaked at 48 hours after injury, whereas noninjured cells remained quiescent. An increased expression of platelet-derived growth factor (PDGF) A mRNA, noted 6 hours after injury, was followed by an increased PDGF AA immunoreactivity in SMCs in and around the zone of injury at 24 and 48 hours after injury. A PDGF A chain antisense oligonucleotide inhibited 87.0±4.0% (
P
<.005) of SMC replication in the injury zone, whereas the corresponding sense oligonucleotide reduced SMC replication by only 37.2%. An antibody to fibroblast growth factor (FGF) almost completely inhibited SMC replication in the injured zone, whereas an antibody to PDGF AA was without effect. Incubation of SMCs with FGF increased PDGF A mRNA levels in SMCs, and 5 μmol/L PDGF A antisense oligonucleotides reduced FGF-induced SMC replication by 62%. Taken together, these results demonstrate that injured rat SMCs in culture release FGF that activates DNA synthesis of neighboring SMCs both by a direct mechanism and by stimulating the production of PDGF AA.
Deletion Polymorphism in the Angiotensin-Converting Enzyme Gene in Patients With a History of Ischemic Stroke
Authors: Margaglione Maurizio , Celentano Egidio , Grandone Elvira , Vecchione Gennaro , Cappucci Giuseppe , Giuliani Nicola , Colaizzo Donatella , Panico Salvatore , Mancini Francesco P. , Di Minno Giovanni
Published: June 2011

AbstractWe evaluated the genotypes of the angiotensin-converting enzyme (ACE) gene in 101 subjects with and 109 subjects without a history of ischemic stroke. All were attending a metabolic ward. The two groups were compared for major risk factors for ischemic events. Genotypes were determined by polymerase chain reaction with oligonucleotide primers flanking the polymorphic region in intron 16 of the ACE gene. Deletion polymorphism of the ACE gene (DD genotype) was shown to be more common in subjects with a history of stroke than in those without (relative risk, 1.76; confidence intervals, 1.02 to 3.05). A positive family history for ischemic complications of atherosclerosis was also more common in subjects with documented events (relative risk, 1.99; confidence intervals, 1.10 to 3.59). DD genotype and a positive family history were strong independent discriminators of cerebral ischemia. Plasma levels of tissue-type plasminogen activator (TPA) and plasminogen activator inhibitor-1 help identify subjects with a history of cerebral ischemic episodes. When such fibrinolytic variables were included in the analysis, the DD genotype still strongly and independently discriminated subjects with a stroke history and significantly interacted with TPA levels >10 ng/mL in such identification. We conclude that in subjects attending a metabolic ward, homozygosity for a deletion polymorphism of the ACE gene consistently discriminates subjects with a stroke history. Interaction with TPA improves such identification.
Association of Chronic Stress With Plasminogen Activator Inhibitor–1 in Healthy Middle-aged Men
Authors: Räikkönen Katri , Lassila Riitta , Keltikangas-Järvinen Liisa , Hautanen Aarno
Published: June 2011

Abstract
The effect of chronic stress on tissue-type plasminogen activator (TPA) and plasminogen activator inhibitor–1 (PAI-1) antigens was studied in 69 healthy middle-aged men. Chronic stress, defined as feelings of fatigue, lack of energy, increased irritability, and demoralization, was positively associated with plasma concentrations of PAI-1 antigen but was unrelated to TPA. The association remained unaltered after controlling for age, smoking, alcohol consumption, and physical activity but became nonsignificant after further controlling for abdominal obesity, BMI, and serum insulin and triglyceride levels. This attenuated association implies that the relationship between vital exhaustion and PAI-1 may be secondary to the effects of the metabolic variables. Thus, the present study shows that long-term stress affects the fibrinolytic system and suggests that obesity and insulin and triglyceride concentrations, which are closely correlated with the fibrinolytic parameters, may mediate the association. These findings are consistent with the hypothesis that chronic stress causes increased synthesis of PAI-1, thus promoting the risk for atherothrombotic disease by decreasing the likelihood of spontaneous fibrinolysis and increasing the likelihood of fibrin deposition.
Effects of Partially Hydrogenated Fish Oil, Partially Hydrogenated Soybean Oil, and Butter on Hemostatic Variables in Men
Authors: Almendingen Kari , Seljeflot Ingebjørg , Sandstad Berit , Pedersen Jan I.
Published: June 2011

Abstract
We have compared the effects of partially hydrogenated fish oil (PHFO diet), partially hydrogenated soybean oil (PHSO diet), and butterfat (butter diet) on fibrinolytic and coagulation variables in 31 young men. The three test margarines, which contributed 78% of total fat in the diets, contained 70% butterfat, PHSO, or PHFO, each with 30% of soybean oil. Fat provided ≈35% of energy, and the content of
trans
-fatty acids was 0.9%, 8.5%, and 8.0% of energy in the butter diet, PHSO diet, and PHFO diet, respectively. All diets contained 420 mg cholesterol per 10 megajoules per day. All subjects consumed all three test diets for 3 weeks, in a random order (crossover design). The PHSO diet resulted in higher levels of plasminogen activator inhibitor type 1 antigen and plasminogen activator inhibitor type 1 activity than the two other test diets. Fibrinogen increased on the butter diet compared with the PHFO diet. No significant differences in the levels of factor VII, fibrinopeptide A,
d
-dimer, tissue plasminogen activator or β-thromboglobulin were observed between the three test diets. The PHFO and the PHSO diets have previously been shown to result in higher levels of Lp(a) compared with the butter diet. The present findings indicate that PHSO has unfavorable antifibrinolytic effects relative to PHFO and butter and that butter may be procoagulant relative to PHFO. More controlled dietary studies are needed to assess definitely the impact of different hydrogenated fats on risk of coronary heart disease.
The Acute Rise in Plasma Fibrinogen Concentration With Exercise Is Influenced by the G-453-A Polymorphism of the β-Fibrinogen Gene
Authors: Montgomery Hugh E. , Clarkson Peter , Nwose O.M. , Mikailidis D.P. , Jagroop I.A. , Dollery Clare , Moult James , Benhizia Ferdaous , Deanfield John , Jubb Mick , World Michael , McEwan Jean R. , Winder Anthony , Humphries Stephen
Published: June 2011

AbstractWe have investigated the effects of chronic physical training and acute intensive exercise on plasma fibrinogen levels and the relationship of these responses to β-fibrinogen G-453-A polymorphism genotype. One hundred fifty-six male British Army recruits were studied at the start of their 10-week basic training, which emphasizes physical fitness. Cohorts were restudied between 0.5 and 5 days after a major 2-day strenuous military exercise (ME) undertaken in their final week of training. Changes in fibrinogen concentration were adjusted for the effects of age, body mass index, and smoking history. Compared with baseline values, fibrinogen concentrations were significantly lower (11.9%,P=.04) at day 5 after ME, consistent with the beneficial effect of training. However, they were higher on days 1 through 3 after ME (suggesting an “acute-phase” response to strenuous exercise) and were maximal on days 1 and 2 (27.2%,P<.001 and 37.1%,P<.001, respectively). Fibrinogen genotype was available in 149 individuals. As expected from previous studies, men with one or more fibrinogen gene A-453 alleles had plasma fibrinogen concentrations slightly but not significantly higher at baseline (4.5%,P=.11). During the acute-phase response (days 2 and 3), however, the degree of rise was strongly related to the presence of the A allele, being 26.7±5.4% (mean±SE), 36.5±11.0%, and 89.2±30.7 for the GG, GA, and AA genotypes, respectively (P=.01). These results confirm that chronic exercise training lowers plasma fibrinogen levels, that intensive exercise generates an acute-phase rise in levels, and that this acute response is strongly influenced by the G/A polymorphism of the β-fibrinogen gene.
Expression of the VLDL Receptor in Endothelial Cells
Authors: Wyne Kathleen L. , Pathak Ravindra K. , Seabra Miguel C. , Hobbs Helen H.
Published: June 2011

Abstract
In this article we describe the cellular distribution of the very low density lipoprotein receptor (VLDLR), a transmembrane protein that is expressed at high concentrations in skeletal muscle, heart, adipose tissue, and brain but in only trace amounts in the liver. Indirect immunofluorescence localization studies were performed in murine and bovine tissues using a rabbit polyclonal anti-human VLDLR antibody. Immunoreactive VLDLR protein was detected in the endothelium of capillaries and small arterioles but not in veins or venules of bovine skeletal muscle, heart, ovary, and brain. In the liver, there was intense staining of the capillaries and arterioles that supply the capsule and hepatic vessels but no staining of the sinusoidal surfaces. We failed to detect any signal from nonendothelial cells in the liver or peripheral organs. The VLDLR was also expressed at high levels on the endothelial surface of bovine coronary arteries; in contrast, little or no staining was seen in aortic endothelium. Antibody staining of cultured bovine coronary artery endothelial cells demonstrated punctate cell-surface staining, as well as staining of large and small cytoplasmic vesicles. This tissue and cell pattern of expression suggests that the VLDLR plays a role in the transport of VLDL or another plasma constituent from the vascular compartment to adjacent tissues.
Hypercholesterolemia With Cholesterol-Enriched LDL and Normal Levels of LDL–Apolipoprotein B
Authors: Vega Gloria Lena , Grundy Scott M.
Published: June 2011

Abstract
One form of hypercholesterolemia is characterized by high levels of LDL cholesterol and normal levels of LDL–apolipoprotein (apo) B. The reason for hypercholesterolemia, therefore, is enrichment of LDL particles with cholesterol. We have reported previously that about one third of patients with primary moderate hypercholesterolemia have this lipoprotein pattern and have no apparent abnormality in LDL–apo B metabolism. The current study was designed to determine whether the combination of the Step I Diet (30% of total calories as fat, <10% saturated fatty acids, and <300 mg per day cholesterol) with or without cholestyramine therapy will correct the hypercholesterolemia in patients of this type. Ten hypercholesterolemic men of this type were identified and recruited into the study. Their LDL cholesterol levels were ≥160 mg/dL and LDL–apo B levels were <120 mg/dL (LDL cholesterol/apo B ratio >1.60). For patient selection, subjects were challenged with a high fat diet (40% of total calories as fat, 18% saturated fatty acids, and 400 mg per day cholesterol) for 6 weeks to confirm persistence of a high LDL cholesterol/apo B ratio. Thereafter, they were started on a Step I Diet, and lipoprotein analyses were repeated. Finally, cholestyramine (16 g per day) was added to the Step I Diet. The Step I Diet alone significantly reduced the LDL cholesterol/apo B ratios and produced a trend toward lowering LDL cholesterol levels. Cholestyramine therapy further reduced LDL cholesterol levels and maintained a normal LDL cholesterol/apo B ratio. The present investigation thus confirms the existence of a form of moderate hypercholesterolemia that arises from a defect in LDL composition. In addition, it demonstrates that the combination of the Step I Diet and cholestyramine therapy corrects this defect and normalizes LDL levels and LDL composition.
Inhibitors of Fibrinolysis Are Elevated in Atherosclerotic Plaque
Authors: Robbie Linda A. , Booth Nuala A. , Brown Paul A.J. , Bennett Bruce
Published: June 2011

Abstract
The proteins of the fibrinolytic system have been examined in the human normal and atherosclerotic arterial wall by immunohistochemical techniques and by quantitative immunoassay of extracts. The concentration of plasminogen activator inhibitor-1 (PAI-1) increased significantly during the progression from normal vessels to fatty streaks to the developed atherosclerotic plaque. Staining for PAI-1 was strongly positive, particularly in the areas adjacent to the plaque. In these areas, PAI-1 appeared to be colocalized with its binding protein vitronectin. α
2
-Antiplasmin (α
2
-AP) was present in the aorta at even higher concentrations than PAI-1; a small but significant increase was seen in some atherosclerotic compared with normal vessel walls. Tissue plasminogen activator (TPA) showed the opposite trend, being lowest in lesions with plaque. Thus, higher concentrations of the two principal inhibitors of fibrinolysis, PAI-1 and α
2
-AP, together with lower levels of TPA, are characteristic of advanced atheromatous lesions. Alteration in the balance of the fibrinolytic system, favoring its inhibition, may predispose to the development or maintenance of atherosclerotic plaque.
Smoking Impairs the Activity of Endothelial Nitric Oxide Synthase in Saphenous Vein
Authors: Higman Dan J. , Strachan Alex M.J. , Buttery Lee , Hicks Robert C.J. , Springall David R. , Greenhalgh Roger M. , Powell Janet T.
Published: June 2011

Abstract
Smoking impairs the endothelium-dependent relaxation of arteries and veins, with the maximum relaxation in response to the calcium ionophore A23187 of saphenous vein rings being reduced from 53±4% in nonsmokers to 27±5% in smokers. We have investigated whether this endothelial dysfunction was attributable to altered activity or concentration of nitric oxide synthase (NOS). The concentration of NOS in saphenous vein endothelium, determined by Western blotting and immunohistochemistry, was not different in nonsmokers and smokers. Nitrite production from vein strips stimulated with A23187 was higher in nonsmokers (median 23.6 nmol·cm
−2
·h
−1
) than smokers (median 3.3 nmol·cm
−2
·h
−1
),
P
=.001, this difference being abolished when vein strips were preincubated in the presence of
N
G
-monomethyl-
l
-arginine. Organ chamber studies to monitor the endothelium-dependent relaxation of vein rings in response to A23187 showed that preincubation of rings from smokers with either
l
-arginine (3 mmol/L) or superoxide dismutase (250 U/mL) did not improve the maximum relaxation. In contrast, preincubation of vein rings from smokers with 20 μmol/L tetrahydrobiopterin increased the maximum relaxation from 27±5% to 51±6%,
P
=.01. Preincubation of vein from smokers with tetrahydrobiopterin also significantly increased nitrite and cGMP production in response to stimulation with A23187. The impaired endothelium-dependent relaxation of saphenous vein rings from smokers appears to be caused by a reduction in the activity of endothelial NOS that is attributable to an inadequate supply of the coenzyme tetrahydrobiopterin.