bluuebunny/crossref_metadata_2025 huggingface dataset:
Platelet-Activating Factor and Oxidized LDL Induce Immune Activation by a Common Mechanism
Authors: Frostegård Johan , Huang Yi Hui , Rönnelid Johan , Schäfer-Elinder Liselotte
Published: June 2011

AbstractPlatelet activating factor (PAF) is a phospholipid with proinflammatory and thrombogenic properties, which has been implicated in inflammatory disorders including vasculitis and asthma. PAF-like compounds are present in oxidized LDL (oxLDL), which has been detected in the atherosclerotic lesion, where it may activate monocytes, macrophages, and T cells. OxLDL may therefore both initiate and perpetuate inflammatory reactions in the artery wall. Herein we demonstrate that PAF has the capacity to induce enhanced interferon gamma (IFN-γ) secretion in peripheral blood mononuclear leukocytes (PBMCs), as does oxLDL. Both oxLDL- and PAF-induced IFN-γ secretions were inhibited by a specific PAF-receptor antagonist, WEB 2170. PAF-like lipids in oxLDL could thus be responsible for oxLDL-induced activation of immune-competent cells. The effects of PAF and oxLDL were inhibited by antibodies to major histocompatibility complex class II and thus depend on accessory cells like monocytes. Both PAF and oxLDL induced tumor necrosis factor-α (TNF-α) synthesis in peripheral blood. PAF-mediated TNF-α production was inhibited by WEB 2170, whereas oxLDL-induced TNF-α was only partially inhibited. These findings indicate that both PAF and oxLDL have the capacity to induce TNF-α, which may increase atherogenesis due to its pleiotropic proinflammatory effects. Our findings suggest that the PAF receptor plays an important role in the inflammatory component of atherosclerosis.
A Novel Mosaic Protein Containing LDL Receptor Elements Is Highly Conserved in Humans and Chickens
Authors: Mörwald Sonja , Yamazaki Hiroyuki , Bujo Hideaki , Kusunoki Jun , Kanaki Tatsuro , Seimiya Kouichi , Morisaki Nobuhiro , Nimpf Johannes , Schneider Wolfgang Johann , Saito Yasushi
Published: June 2011

Abstract
Certain receptors belonging to the LDL receptor (LDLR) gene family appear to constitute a newly identified branch whose members are expressed in brain, in addition to other tissues. In support of this concept, we have now discovered the expression and delineated the molecular structures of a representative of this emerging branch from two such diverse species as human and chicken. This membrane receptor, called LR11 and thus far only known to exist in the rabbit, is a complex seven-domain mosaic protein containing, among other structural elements, a cluster of 11 LDLR ligand-binding repeats and a domain with homology to VPS10, a yeast receptor for vacuolar protein sorting. Cytoplasmic signature sequences define the receptor as competent for endocytosis. The most striking properties of LR11s are their (1) high degree of structural conservation (>80% identity among mammals and birds), with 100% identity in the membrane-spanning and cytoplasmic domains of rabbit and human; (2) lack of regulation by cholesterol and estrogen; and (3) expression in brain. The features of LR11 suggest important roles in intercellular and intracellular ligand transport processes, some of which it may share with other brain-specific LDLR family members.
Metabolic Basis of Hypotriglyceridemic Effects of Insulin in Normal Men
Authors: Malmström Raija , Packard Christopher J. , Watson Timothy D. G. , Rannikko Sirpa , Caslake Muriel , Bedford Dorothy , Stewart Philip , Yki-Järvinen Hannele , Shepherd James , Taskinen Marja-Riitta
Published: June 2011

Abstract
The mechanism by which acute insulin administration alters VLDL apolipoprotein (apo) B subclass metabolism and thus plasma triglyceride concentration was evaluated in 7 normolipidemic healthy men on two occasions, during a saline infusion and during an 8.5-hour euglycemic hyperinsulinemic clamp (serum insulin, 490±30 pmol/L). During the insulin infusion, plasma triglycerides decreased by 22% (
P
<.05), and serum free fatty acid decreased by 85% (
P
<.05). The plasma concentration of VLDL1 apo B fell 32% during the insulin infusion, while that of VLDL2 apo B remained constant. A bolus injection of [3-
2
H]leucine was given on both occasions to trace apo B kinetics in the VLDL1 and VLDL2 subclasses (Svedberg flotation rate, 60-400 and 20-60, respectively), and the kinetic basis for the change in VLDL levels caused by insulin was examined using a non-steady-state multicompartmental model. The mean rate of VLDL1 apo B synthesis decreased significantly by 35% (
P
<.05) after 0.5 hour of the insulin infusion (523±87 mg/d) compared with the saline infusion (808±91 mg/d). This parameter was allowed to vary with time to explain the fall in VLDL1 concentration. After 8.5 hours of hyperinsulinemia, the rate of VLDL1 apo B synthesis was 51% lower (321±105 mg/d) than during the saline infusion (651±81 mg/d,
P
<.05). VLDL2 apo B production was similar during the saline (269±35 mg/d) and insulin (265±37 mg/d) infusions. No significant changes were observed in the fractional catabolic rates of either VLDL1 or VLDL2 apo B. We conclude that acute hyperinsulinemia lowers plasma triglyceride and VLDL levels principally by suppressing VLDL1 apo B production but has no effect on VLDL2 apo B production. These findings indicate that the rates of VLDL1 and VLDL2 apo B production in the liver are independently regulated.
Induction of the Acute-Phase Reaction Increases Heparin-Binding Proteins in Plasma
Authors: Young Edward , Podor Thomas J. , Venner Thomas , Hirsh Jack
Published: June 2011

AbstractWe have previously demonstrated that the nonspecific binding of unfractionated heparin (UFH) to plasma proteins has a marked modulating effect on its anticoagulant activity. Since some heparin-binding proteins are also acute-phase-reactant proteins, we explored the possibility that the induction of the acute-phase response can increase the plasma concentrations of heparin-binding proteins. The recovery of a fixed amount of UFH or low-molecular-weight heparin (LMWH) added in vitro to rat plasma samples obtained at various time intervals after the administration of intravenous endotoxin or subcutaneous turpentine was compared with that of saline-treated control animals. The anti–factor Xa activity was measured in the plasma samples before and after the addition of a chemically modified low-affinity heparin (LAH) to displace the proportion of the added heparin that is reversibly bound to plasma proteins. Our results show that at 6 hours post–endotoxin and at 24 hours post–turpentine treatment, virtually no anti–factor Xa activity could be measured in the plasma samples, while the expected levels were obtained for control plasma. After the addition of LAH to displace protein-bound UFH, essentially the same anti–factor Xa levels were measured in the plasma from all three treatment groups. These results indicate that induction of the acute-phase reaction can dramatically increase the levels of heparin-binding proteins in rat plasma. In addition, we compared the anti–factor Xa recovery of UFH with that of an LMWH from the plasma of endotoxin- and saline-treated rats and demonstrated that LMWH binds less to plasma proteins than UFH, even in plasma in which the levels of heparin-binding proteins are markedly elevated. The recovery of a fixed amount of UFH added in vitro to human plasma from septic patients was also reduced, but not to the same extent as seen in rat plasma. Removal of candidate heparin-binding and acute-phase proteins by immunodepletion indicated that vitronectin plays an important role in the nonspecific binding of UFH in patient plasma.
Structural and Functional Comparison of HDL From Homologous Human Plasma and Follicular Fluid
Authors: Jaspard Béatrice , Fournier Nathalie , Vieitez Gérard , Atger Véronique , Barbaras Ronald , Vieu Claude , Manent Jeanine , Chap Hugues , Perret Bertrand , Collet Xavier
Published: June 2011

Abstract
In the preovulatory period, follicular fluid contains only HDL. Biochemical characterization of such lipoproteins showed that follicular fluid HDLs were cholesterol-poor particles compared with serum HDLs, whereas the amount of phospholipids, expressed as percent weight, was significantly higher in follicular fluid HDLs (28.5%) than in serum HDLs (25.0%,
P
<.05). The amount of apolipoprotein (apo) A-IV per apo A-I was significantly higher in follicular fluid than in serum (0.77 versus 0.58 mg/g apo A-I,
P
<.02). To explore the role of HDLs as cholesterol acceptors in physiological media, we compared the ability of either whole human follicular fluids or homologous sera to promote cellular cholesterol efflux using Fu5AH rat hepatoma cells. At equivalent concentrations of HDL cholesterol in follicular fluid and in serum,
t
1/2
values for cholesterol efflux were in the same range. In addition, estimated maximal efflux values were not significantly different in follicular fluid and serum (45.9% and 49.6%, respectively), as were
K
m
values (0.064 and 0.071 mmol/L HDL cholesterol, respectively). In addition, isolated HDLs displayed the same capacity to promote cellular cholesterol efflux in both media. Thus, the kinetics and dose-response data between these two physiological media showed that HDLs play the major role in cellular cholesterol efflux. The rate of cholesterol esterification, as measured in the presence of cells, was significantly higher in follicular fluid than in serum at constant HDL cholesterol concentrations, whereas the rate of esterified cholesterol transfer toward added LDL was lower. In contrast, in a cell-free system, lecithin:cholesterol acyltransferase activity represented only 26% of that in serum HDL, whereas cholesterol ester transfer protein activities were comparable. In summary, in this particular model, we confirmed the essential role of HDLs as physiological acceptors in the removal of cellular cholesterol.
Oxidized Low Density Lipoproteins in Patients With Transplant-Associated Coronary Artery Disease
Authors: Holvoet Paul , Stassen Jean-Marie , Van Cleemput Johan , Collen Désiré , Vanhaecke Johan
Published: June 2011

Abstract
—The monoclonal antibody 4E6–based ELISA was used to quantify levels of oxidized LDL in plasma of 65 control subjects, 47 patients transplanted for dilated cardiomyopathy (DCM), and 60 patients transplanted for coronary artery disease (CAD). Levels of oxidized LDL were 0.68±0.039 mg/dL (mean±SEM), 1.27±0.14 mg/dL (
P
<.001 versus control), and 1.73±0.13 mg/dL (
P
<.001 versus control and <0.01 versus DCM), respectively. Levels of oxidized LDL were significantly lower in transplanted patients with angiographically normal coronary arteries (grade 0, 1.16±0.053 mg/dL; n=79) than in patients with mild (grade 1, 2.13±0.30 mg/dL; n=18;
P
<.001 versus grade 0) or severe (grade 2, 3.18±0.45 mg/dL; n=10;
P
<.001 versus grade 0 and
P
<.05 versus grade 1) coronary artery stenosis. Logistic regression analysis identified three parameters that were significantly and independently correlated with posttransplant CAD: plasma levels of oxidized LDL (
P
=.0001), length of follow-up (
P
=.0008), and donor age (
P
=.047). Thus, the present study demonstrates that plasma levels of oxidized LDL correlate with the extent of CAD in heart transplant patients and suggests that elevated levels of oxidized LDL may be a marker for CAD.
Differential Effect of Genistein on the Stimulation of Cholesterol Production by Basic Protein II in Normal and HyperapoB Fibroblasts
Authors: Kwiterovich Peter O. , Motevalli Mahnaz
Published: June 2011

Abstract
—We studied further the basis for the abnormal effect of human serum basic protein II (BP II) on cholesterol production in hyperapobetalipoproteinemia (hyperapoB) fibroblasts and whether this effect involves protein tyrosine kinase phosphorylation (TKP). Genistein, a specific inhibitor of TKP was used as a probe. Compared with normal cells, BP II stimulated significantly the cellular mass of total cholesterol (6.4-fold), unesterified cholesterol (3.6-fold), and esterified cholesterol (6.7-fold) in hyperapoB fibroblasts. The addition of genistein to BP II in hyperapoB cells markedly inhibited these abnormal stimulatory effects of BP II on cell sterol mass. In normal cells, the addition of genistein to BP II produced an opposite effect: a marked stimulation in the mass of total (5.5-fold) and esterified (18.3-fold) cholesterol and a decrease in unesterified cholesterol (3.4-fold). These effects of genistein on the formation of cellular cholesterol by BP II were both time and concentration dependent. The inhibition of the stimulatory effect of BP II on cholesterol production by genistein in hyperapoB cells may be mediated through 3-hydroxy 3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme of cholesterol biosynthesis, since the rate of incorporation of [
14
C]acetate, but not [
3
H]mevalonate, into unesterified cholesterol was decreased by genistein in the hyperapoB cells. When the mass of cell total cholesterol in the cells treated with BP II was subtracted from those treated with BP II plus genistein, a negative number was produced in each of the six hyperapoB cell lines, while each of the normal cell lines retained a positive number. The mean difference for the mass of total cholesterol between the hyperapoB and normal fibroblasts under these conditions was 128.2 nmol/mg cell protein, a difference that was separated by >3 SD. This study supports further the tenet that there is a defect in the response of hyperapoB cells to BP II and that this defect results in an abnormality in cholesterol metabolism that appears mediated through a protein TKP-mediated process.
Priming of Platelet α
IIb
β
3
by Oxidants Is Associated With Tyrosine Phosphorylation of β
3
Authors: Irani Kaikobad , Pham Youm , Coleman Lindsay D. , Roos Christine , Cooke Glen E. , Miodovnik Amir , Karim Nayeem , Wilhide Calvin C. , Bray Paul F. , Goldschmidt-Clermont Pascal J.
Published: June 2011

Abstract
—Reactive oxygen species play an important role at the site of vascular injuries and arterial thromboses. We studied the mechanism mediating platelet aggregation induced by H
2
O
2
, a major cellular oxidant. Exposure to H
2
O
2
triggered platelet aggregation, but only when the platelets were stirred. Strong platelet aggregation induced by H
2
O
2
required the presence of the tyrosine phosphatase inhibitor sodium orthovanadate (NaVO
4
) and was dependent on the participation of integrin α
IIb
β
3
(glycoprotein IIb-IIIa). A specific inhibitor of α
IIb
β
3
blocked platelet aggregation induced by H
2
O
2
and NaVO
4
, thus confirming that aggregation requires this receptor. In the presence of H
2
O
2
and NaVO
4
, multiple platelet substrates were phosphorylated on tyrosine. Such tyrosine kinase response was necessary but not sufficient to activate α
IIb
β
3
, as detected by binding of soluble fibrinogen to platelets. Stirring of the platelets exposed to H
2
O
2
and NaVO
4
was also needed to allow for binding of fibrinogen to α
IIb
β
3
. The tyrosine kinase inhibitor genistein was able to block platelet aggregation induced by H
2
O
2
and NaVO
4
, thus confirming that tyrosine kinase activity was needed to trigger α
IIb
β
3
activation on stirring.
N
-Acetyl-
l
-cysteine, a cell-permeant antioxidant, blocked the tyrosine phosphorylation of platelet substrates and also the platelet aggregation induced by H
2
O
2
and NaVO
4
. We found that β
3
was phosphorylated on tyrosine in platelets exposed to H
2
O
2
and NaVO
4
, even in the absence of aggregation. Hence, tyrosine phosphorylation of β
3
might contribute to the “priming” of α
IIb
β
3
induced by H
2
O
2
and NaVO
4
, whereby the receptor can become activated on stirring of the platelets.
Common Variants in the Promoter of the Hepatic Lipase Gene Are Associated With Lower Levels of Hepatic Lipase Activity, Buoyant LDL, and Higher HDL2Cholesterol
Authors: Zambon Alberto , Deeb Samir S. , Hokanson John E. , Brown B. Greg , Brunzell John D.
Published: June 2011

Abstract—Increased hepatic lipase (HL) activity is associated with small, dense, low density lipoprotein (LDL) and low high density lipoprotein2(HDL2) cholesterol (-C) levels. A polymorphism in the promoter region of the HL gene (LIPC) is associated with HDL-C levels. To test whether this association is mediated by differences in HL activity between differentLIPCpromoter genotypes, theLIPCpromoter polymorphism at position −250 (G→A), HL activity, LDL buoyancy, and HDL-C levels were studied in white normolipidemic men and men with coronary artery disease (CAD). The less commonAallele (frequency=0.21 and 0.25 in normal and CAD subjects, respectively) was associated with lower HL activity (P<0.005 by ANOVA) and buoyant LDL particles (P≤0.01) in both groups. Normal and CAD subjects heterozygous for theAallele had lower HL activity (by 24% and 29%, respectively) and significantly more buoyant LDL particles. Homozygosity for this allele (AA) was associated with an even lower HL activity in normal (−26%) and CAD (−46%) subjects. TheAallele was associated with higher HDL2-C in CAD patients (P=0.007); heterozygotes and homozygotes for theAallele had a 92% and a 140% higher HDL2-C level (P<0.01) than didGGindividuals. In a small number of normolipidemic subjects, the same trend in HDL2-C was seen. In a univariate analysis, theLIPCgenotype accounted for 20% to 32% of the variance in HL levels among normal subjects and CAD patients, respectively. After adjustment for HL, the association betweenLIPCgenotype and LDL buoyancy was no longer significant, suggesting that the effect ofLIPCgenotype on LDL buoyancy is mediated by its effects on HL activity. TheLIPCAallele was more frequent in Japanese-Americans and African-Americans than in whites. In summary, these results suggest that variants in theLIPCpromoter may significantly contribute to the variance in levels of HL activity and consequently, to the prevalence of the atherogenic small, dense, LDL particles and low HDL2-C levels.
Tibolone Prevents Atherosclerotic Lesion Formation in Cholesterol-Fed, Ovariectomized Rabbits
Authors: Zandberg Pieter , Peters Jan L. M. , Demacker Pierre N. M. , Smit Martin J. , de Reeder Ernst G. , Meuleman Dirk G.
Published: June 2011

Abstract
—Tibolone (Org OD14), a synthetic steroid with estrogenic and progestogenic/androgenic properties, is clinically effective for the treatment of climacteric symptoms and the prevention and treatment of osteoporosis in postmenopausal women. The effect on atherogenesis, however, is not known. In the current study, we investigated the effect of tibolone in comparison with that of estradiol and norethisterone acetate on atherogenesis in 140 ovariectomized New Zealand White rabbits that had been induced by an atherogenic diet (0.4% cholesterol, 20 weeks). Tibolone at 18, 6, or 2 mg/d orally completely prevented cholesterol accumulation and fatty streak formation in the aorta; the impairment of endothelium-dependent smooth muscle relaxation of the aorta; and complex lesion formation after endothelial denudation in the carotid artery. Tibolone also reduced the increased postovariectomy plasma lipid concentrations. Analysis of the results, however, indicated that a substantial part of the strong, beneficial effects were plasma lipid independent. Compared with subcutaneous estradiol decanoate (150 μg once weekly) and oral 17β-estradiol (4 mg/d), the effects of tibolone were more pronounced at equipotent uterotropic activity. Norethisterone acetate (1 mg/d) did not affect atherosclerotic lesion formation. There are no indications that the progestogenic/androgenic properties of tibolone counteracted its atheroprotective effect on the vessel wall. Therefore, tibolone has the intrinsic potential to be a compound that protects the arterial vessel wall against atherosclerotic processes.
Impact of Apo(a) Length Polymorphism and the Control of Plasma Lp(a) Concentrations
Authors: Gaw Allan , Brown E. Ann , Ford Ian
Published: June 2011

Abstract
—Plasma lipoprotein(a) [Lp(a)] levels are believed to be controlled predominantly by the apolipoprotein(a) [
APO(a)
] gene, which encodes the apo(a) glycoprotein, a key constituent of the Lp(a) particle. Previously, it has been accepted that the plasma Lp(a) level is inversely proportional to apo(a) length. To examine this relationship in greater detail, 1500 unrelated, homogeneous (sex, race, age, plasma lipids) subjects were studied, from which 769 were identified with a single-expressing
APO(a)
allele. A bimodal frequency distribution of apo(a) isoforms was observed. As expected, there was a general inverse relationship between apo(a) isoform size and Lp(a) level. However, when groups with equivalent single-expressing apo(a) isoforms were studied, it was clear that although smaller isoforms were associated on average with higher levels, they were also associated with the greatest variability in level. After logarithmic transformation of Lp(a) data, the overall contribution of the apo(a) length polymorphism was calculated to be 38%. However, in subjects with apo(a) isoforms of ≤20 kringle-4 (K-4) repeats, only 9% of the variability in Lp(a) concentration is explicable on the basis of the apo(a) length polymorphism. In those with apo(a) isoforms of >20 K-4 repeats, the corresponding contribution is 10%. We conclude that the contribution of the apo(a) isoform size to the control of plasma Lp(a) level is considerably lower than previously calculated, because the variability in plasma Lp(a) concentration is not uniform across the apo(a) size spectrum.
Hormone Replacement Therapy Improves Cardiovascular Risk by Lowering Plasma Viscosity in Postmenopausal Women
Authors: Rosenson Robert S. , Tangney Christine C. , Mosca Lori J.
Published: June 2011

Abstract
—Hormone replacement therapy may protect against cardiovascular disease through several mechanisms that have variable actions on the major determinants of plasma viscosity. Plasma viscosity is an important predictor of incident and recurrent cardiovascular events and mortality in coronary heart disease patients. The effect of estrogen alone or in combination with progestin on plasma viscosity is not known. Using a randomized, double-blind design, we examined the impact of the following daily hormone regimens on plasma viscosity in 23 women: (1) 1 mg estradiol and 2.5 mg medroxyprogesterone (n=7); (2) 1 mg estradiol alone (n=8); and (3) placebo (n=8). Plasma viscosity, fibrinogen, and standard lipoprotein levels were determined at baseline and after 12 weeks of intervention. Plasma viscosity was measured at 37°C with a coaxial microviscometer. Fibrinogen was measured by the Clauss method. Significant changes in plasma viscosity (mPa · s) levels occurred among treatment groups (
P
<0.01) after the intervention. Plasma viscosity was significantly reduced with estrogen replacement therapy (
P
<0.01). These data demonstrate that estrogen replacement therapy lowers plasma viscosity. This study suggests an additional mechanism for the cardiovascular protection conferred to postmenopausal women on estrogen replacement therapy.
Peripheral Arterial Disease in the Elderly
Authors: Meijer Wouter T. , Hoes Arno W. , Rutgers Dominique , Bots Michiel L. , Hofman Albert , Grobbee Diederick E.
Published: June 2011

Abstract
—To assess the age- and sex-specific prevalence of peripheral arterial disease (PAD) and intermittent claudication (IC) in an elderly population, we performed a population-based study in 7715 subjects (40% men, 60% women) aged 55 years and over. The presence of PAD and IC was determined by measuring the ankle-arm systolic blood pressure index (AAI) and by means of the World Health Organization/Rose questionnaire, respectively. PAD was considered present when the AAI was <0.90 in either leg. The prevalence of PAD was 19.1% (95% confidence interval, 18.1% to 20.0%): 16.9% in men and 20.5% in women. Symptoms of IC were reported by 1.6% (95% confidence interval, 1.3% to 1.9%) of the study population (2.2% in men, 1.2% in women). Of those with PAD, 6.3% reported symptoms of IC (8.7% in men, 4.9% in women), whereas in 68.9% of those with IC an AAI below 0.90 was found. Subjects with an AAI <0.90 were more likely to be smokers, to have hypertension, and to have symptomatic or asymptomatic cardiovascular disease compared with subjects with an AAI of 0.90 or higher. The authors conclude that the prevalence of PAD in the elderly is high whereas the prevalence of IC is rather low, although both prevalences clearly increase with advancing age. The vast majority of PAD patients reports no symptoms of IC.
Recombinant von Willebrand Factor Fragment AR545C Inhibits Platelet Aggregation and Enhances Thrombolysis With rtPA in a Rabbit Thrombosis Model
Authors: Gurevitz Osnat , Goldfarb Abraham , Hod Hanoch , Feldman Monica , Shenkman Boris , Varon David , Eldar Michael , Inbal Aida
Published: June 2011

Abstract
—Platelet adhesion to exposed subendothelium is mediated by platelet receptor glycoprotein Ib and polymeric von Willebrand factor (vWF). To improve the results of coronary arterial thrombolysis, fragments of vWF with enhanced glycoprotein Ib binding competitive with native vWF have been proposed as adjuvants to recombinant tissue-type plasminogen activator (rtPA). We designed a recombinant vWF fragment spanning Ala444 to Asp730 that contains the Arg545Cys mutation (named AR545C) and analyzed its antiplatelet properties in vitro and in vivo. AR545C-platelet interaction was assessed by ristocetin or botrocetin-induced platelet agglutination, or interaction with extracellular matrix under arterial flow conditions. AR545C showed enhanced reactivity with platelet glycoprotein Ib at low concentrations of ristocetin, and 60% bound spontaneously to platelets. AR545C inhibited ristocetin-induced platelet agglutination in a dose-dependent manner, with a concentration necessary to inhibit 50% of agglutination of 0.16±0.04 μmol/L. The inhibitory effect of AR545C on rabbit botrocetin-induced platelet agglutination was also dose dependent, with a concentration necessary to inhibit 50% of agglutination of 0.3 to 0.5 μmol/L. AR545C also completely inhibited aggregate formation and decreased the adhesion of platelets to extracellular matrix by 62.5%. The effect of AR545C on thrombolysis with rtPA was evaluated using a modified rabbit femoral thrombosis model. Local injection of AR545C into the thrombosed segment of rabbit femoral artery significantly shortened the time to reperfusion with rtPA (60±17.3 versus 103±15.2 minutes,
P
=.05) and significantly prolonged the total patency time (175 versus 21 minutes,
P
=.04). No significant difference was found in the reperfusion rate or time to reocclusion. AR545C is a potential antithrombotic agent that enhances the thrombolytic effect of rtPA in the rabbit model.
Shear Stress Activates p60src-Ras-MAPK Signaling Pathways in Vascular Endothelial Cells
Authors: Jalali Shila , Li Yi-Shuan , Sotoudeh Mohammad , Yuan Suli , Li Song , Chien Shu , Shyy John Y-J.
Published: June 2011

Abstract
—The aim of this study was to elucidate the upstream signaling mechanism that mediates the fluid shear stress activation of mitogen-activated protein kinases (MAPKs), including c-Jun NH
2
-terminal kinase (JNK) and extracellular signal–regulated kinases (ERKs), in vascular endothelial cells (ECs). Our results indicate that p60src is rapidly activated by fluid shear stress in bovine aortic endothelial cells (BAECs). Shear stress induction of the hemagglutinin (HA) epitope–tagged HA-JNK1 and the Myc epitope–tagged Myc-ERK2 was significantly attenuated by v-src(K295R) and c-src(K295R), the kinase-defective mutants of v-src and c-src, respectively. HA-JNK1 and Myc-ERK2 were activated by c-src(F527), a constitutively activated form of p60src, and the activation was abolished by RasN17, a dominant-negative mutant of p21ras. In contrast, although HA-JNK1 and Myc-ERK2 were also activated by RasL61, an activated form of p21ras, the activation was not affected by v-src(K295R). These results indicate that p60src is upstream to the Ras-JNK and Ras-ERK pathways in response to shear stress. The shear stress inductions of the promoters of monocyte chemotactic protein-1 (MCP-1) and c-
fos
, driven by TPA-responsive element (TRE) and serum-responsive element (SRE), respectively, were attenuated by v-src(K295R). This attenuation is associated with decreased transcriptional activities of c-Jun and Elk-1, the transcription factors targeting TRE and SRE, respectively. Thus, p60src plays a critical role in the shear stress activation of MAPK pathways and induction of Activating Protein-1 (AP-1)/TRE and Elk-1/SRE–mediated transcription in ECs.
Effects of Reducing Dietary Saturated Fatty Acids on Plasma Lipids and Lipoproteins in Healthy Subjects
Authors: Ginsberg Henry N. , Kris-Etherton Penny , Dennis Barbara , Elmer Patricia J. , Ershow Abby , Lefevre Michael , Pearson Thomas , Roheim Paul , Ramakrishnan Rajasekhar , Reed Roberta , Stewart Kent , Stewart Paul , Phillips Katherine , Anderson Nancy
Published: June 2011

Abstract
—Few well-controlled diet studies have investigated the effects of reducing dietary saturated fatty acid (SFA) intake in premenopausal and postmenopausal women or in blacks. We conducted a multicenter, randomized, crossover-design trial of the effects of reducing dietary SFA on plasma lipids and lipoproteins in 103 healthy adults 22 to 67 years old. There were 46 men and 57 women, of whom 26 were black, 18 were postmenopausal women, and 16 were men ≥40 years old. All meals and snacks, except Saturday dinner, were prepared and served by the research centers. The study was designed to compare three diets: an average American diet (AAD), a Step 1 diet, and a low-SFA (Low-Sat) diet. Dietary cholesterol was constant. Diet composition was validated and monitored by a central laboratory. Each diet was consumed for 8 weeks, and blood samples were obtained during weeks 5 through 8. The compositions of the three diets were as follows: AAD, 34.3% kcal fat and 15.0% kcal SFA; Step 1, 28.6% kcal fat and 9.0% kcal SFA; and Low-Sat, 25.3% kcal fat and 6.1% kcal SFA. Each diet provided ≈275 mg cholesterol/d. Compared with AAD, plasma total cholesterol in the whole group fell 5% on Step 1 and 9% on Low-Sat. LDL cholesterol was 7% lower on Step 1 and 11% lower on Low-Sat than on the AAD (both
P
<.01). Similar responses were seen in each subgroup. HDL cholesterol fell 7% on Step 1 and 11% on Low-Sat (both
P
<.01). Reductions in HDL cholesterol were seen in all subgroups except blacks and older men. Plasma triglyceride levels increased ≈9% between AAD and Step 1 but did not increase further from Step 1 to Low-Sat. Changes in triglyceride levels were not significant in most subgroups. Surprisingly, plasma Lp(a) concentrations increased in a stepwise fashion as SFA was reduced. In a well-controlled feeding study, stepwise reductions in SFA resulted in parallel reductions in plasma total and LDL cholesterol levels. Diet effects were remarkably similar in several subgroups of men and women and in blacks. The reductions in total and LDL cholesterol achieved in these different subgroups indicate that diet can have a significant impact on risk for atherosclerotic cardiovascular disease in the total population.
Influence of Oscillatory and Unidirectional Flow Environments on the Expression of Endothelin and Nitric Oxide Synthase in Cultured Endothelial Cells
Authors: Ziegler Thierry , Bouzourène Karima , Harrison Vanessa J. , Brunner Hans R. , Hayoz Daniel
Published: June 2011

Abstract
—In vivo, endothelial cells (ECs) are subjected to a complex mechanical environment composed of shear stress, pressure, and circumferential stretch. The aim of this study was to subject bovine aortic ECs to a pulsatile pressure oscillating from 70 to 130 mm Hg (mean of 100 mm Hg) in combination with pulsatile shear stresses from 0.1 to 6 dyne/cm
2
(1 dyne/cm
2
=0.1 N/m
2
) with or without a cyclic circumferential stretch of 4% for 1, 4, and 24 hours. The effect of highly reversing oscillatory shear stress (range −3 to +3 dyne/cm
2
, mean of 0.3 dyne/cm
2
) typical of regions prone to the development of atherosclerotic plaques was also studied at 4 and 24 hours. Endothelin-1 (ET-1) and endothelial constitutive nitric oxide synthase (ecNOS) mRNA expression was time and mechanical force dependent. ET-1 mRNA was maximal at 4 hours and decreased to less than static culture expression at 24 hours, whereas ecNOS mRNA increased over time. Pressure combined with low shear stress upregulated ET-1 and ecNOS mRNA compared with static control. Additional increase in expression for both genes was observed under a combination of higher shear stress and pressure. A cyclic circumferential stretch of 4% did not induce a further increase in ET-1 and ecNOS mRNA at either low or high shear stress. Oscillatory shear stress with pressure induced a higher expression of ET-1 mRNA but lower expression of ecNOS mRNA compared with unidirectional shear stress and pressure. We have shown that the combination of pressure and oscillatory shear stress can downregulate ecNOS levels, as well as upregulate transient expression of ET-1, compared with unidirectional shear stress. These results provide a new insight into the exact role of mechanical forces in endothelial dysfunction in regions prone to the development of atherosclerosis.
Apolipoprotein B-48 or Its Apolipoprotein B-100 Equivalent Mediates the Binding of Triglyceride-Rich Lipoproteins to Their Unique Human Monocyte-Macrophage Receptor
Authors: Gianturco Sandra H. , Ramprasad M. P. , Song Ruiling , Li Ran , Brown Matthew L. , Bradley William A.
Published: June 2011

Abstract
—Studies in animals and humans have demonstrated uptake of plasma chylomicrons (triglyceride-rich lipoprotein [TGRLP] of S
f
>400) by accessible macrophages in vivo. One potential mechanism is via a unique receptor pathway we previously identified in human blood and THP-1 monocytes and macrophages for the lipoprotein lipase (LpL)– and apolipoprotein (apo) E–independent, high-affinity, specific binding of plasma chylomicrons and hypertriglyceridemic VLDL (HTG-VLDL) to cell-surface membrane-binding proteins (MBP 200, 235; apparent
M
r
200, 235 kD on SDS-PAGE) that leads to lipid accumulation in vitro. Competitive binding studies reported here demonstrate that anti-apoB antibodies specifically block the high-affinity binding of TGRLP to this receptor on THP-1 cells and on ligand blots. LpL, which binds to an N-terminal domain of apoB, also inhibits TGRLP binding both to this site on THP-1s and to MBP 200, 235 by binding to apoB. Chylomicrons of S
f
>1100 that contain apoB-48, but not apoB-100, bind specifically to MBP 200, 235, and this binding is blocked by anti-apoB IgG. In contrast, lactoferrin and heparin do not inhibit TGRLP binding. We conclude that the receptor-binding domain is within apoB-48 (or an equivalent in apoB-100) near the LpL-binding domain, but not a heparin-binding domain. Uptake of TGRLP by this mechanism could provide essential nutrients or, in HTG, cause excess lipid accumulation and foam cell formation.
Human Apolipoproteins A-I and A-II in Cell Cholesterol Efflux
Authors: Chiesa Giulia , Parolini Cinzia , Canavesi Monica , Colombo Nicoletta , Sirtori Cesare R. , Fumagalli Remo , Franceschini Guido , Bernini Franco
Published: June 2011

Abstract
—The first step in reverse cholesterol transport is the movement of cholesterol out of cells onto lipoprotein acceptors in the interstitial fluid. The contribution of specific lipoprotein components to this process remains to be established. In this study, the role of human apolipoproteins (apo) A-I and A-II in the efflux of cellular cholesterol was investigated in transgenic mouse models in which the expression of murine apoA-I was abolished due to gene targeting (A-IKO). Serum from A-IKO mice and from mice expressing human apoA-I and/or human apoA-II was incubated with [
3
H]cholesterol-labeled Fu5AH rat hepatoma cells for 4 hours at 37°C. The cholesterol efflux to the serum of A-IKO mice was markedly lower than that to the serum of mice transgenic for human apoA-I (5.0±1.5% versus 25.0±4.0%). Expression of human apoA-II alone did not modify the cholesterol efflux capacity of A-IKO mouse serum. Cholesterol efflux to serum of mice expressing human apoA-II together with human apoA-I was significantly lower than that to human apoA-I mouse serum (20.0±2.3% versus 25.0±4.0%). Regression analysis of cholesterol efflux versus the lipid/apolipoprotein concentrations of mouse serum suggested that 3 independent factors contribute to determine the cholesterol efflux potential of serum: the apolipoprotein composition of HDL, the serum concentration of HDL phospholipids, and the presence of a small fraction of particles containing apoA-I.
Effect of Thrombolytic Therapy on Platelet Expression and Plasma Concentration of PECAM-1 (CD31) in Patients With Acute Myocardial Infarction
Authors: Serebruany Victor L. , Gurbel Paul A.
Published: June 2011

Abstract—Animal studies have shown that the administration of antibodies against platelet/endothelial cell adhesion molecule-1 (PECAM-1) before reperfusion can reduce infarct size. The purpose of the present study was to define the effects of thrombolytic therapy in acute myocardial infarction (AMI) patients on the platelet expression and plasma concentrations of PECAM-1 at prespecified time points after attempted reperfusion. The plasma concentration and platelet expression of PECAM-1 were determined in 23 AMI patients enrolled in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-III) trial before thrombolysis and at 3, 6, 12, and 24 hours thereafter and compared with 22 healthy controls. At baseline, PECAM-1 was expressed significantly more on the platelet surface in the AMI patients than in controls (P=0.027) while soluble PECAM-1 plasma levels were almost identical between groups. There were no significant diurnal variations in both plasma and platelet PECAM-1 levels in controls. A significant decrease in platelet PECAM-1 expression was observed 3 hours after thrombolysis (P=0.03) compared with baseline, followed by a significant increase (P=0.004) in fluorescence intensity later at 24 hours after thrombolysis. Conversely, a significant increase in soluble PECAM-1 was observed 3 hours after thrombolysis (P=0.02), followed by a significant decrease later at 24 hours after attempted reperfusion (P=0.03). The expression of platelet-bound PECAM-1 is increased in AMI patients. Discordantly directed changes in soluble and platelet PECAM-1 after the first 24 hours after thrombolytic therapy may represent redistribution of the whole PECAM-1 pool. Further investigation of the possible role of PECAM-1 and the relationship between its soluble and platelet fractions in AMI are warranted.
Adaptive Remodeling of Internal Elastic Lamina and Endothelial Lining During Flow-Induced Arterial Enlargement
Authors: Masuda Hirotake , Zhuang Yong-Jie , Singh Tej M. , Kawamura Koichi , Murakami Masayo , Zarins Christopher K. , Glagov Seymour
Published: June 2011

Abstract
—Gaps in the internal elastic lamina (IEL) have been observed in arteries exposed to high blood flow. To characterize the nature and consequences of this change, blood flow was increased in the carotid arteries of 56 adult, male, Japanese white rabbits by creating an arteriovenous fistula between the common carotid artery and the external jugular vein. The common carotid artery proximal to the arteriovenous fistula was studied at intervals from 1 hour to 8 weeks after exposure to high flow. In the controls, the IEL showed only the usual, small, physiological holes, 2 to 10 μm in diameter. At 3 days, some of the holes in the IEL had become enlarged, but they could not be detected by scanning electron microscopy, despite manifest endothelial cell proliferation. At 4 days, gaps in the IEL appeared as small, luminal surface depressions, 15 to 50 μm wide. At 7 days, the gaps in the IEL had enlarged and formed circumferential, luminal depressions occupying 15±5% of the lumen surface. Endothelial cell proliferation persisted in the gaps while proliferative activity decreased where the IEL remained intact. At 4 weeks, as the artery became elongated and dilated, the gaps in the IEL widened as intercommunicating circumferential and longitudinal luminal depressions occupying 64±5% of the lumen surface. At 8 weeks, the rate of elongation and dilatation of the artery slowed and the widening of the gaps in the IEL diminished. Endothelial cells covered the gaps throughout. We conclude that flow-induced arterial dilatation is accompanied by an adaptive remodeling of the intima. The gaps in the IEL permit an increase in lumen surface area while endothelial cell proliferation assures a continuous cell lining throughout.
A Systematic Analysis of 40 Random Genes in Cultured Vascular Smooth Muscle Subtypes Reveals a Heterogeneity of Gene Expression and Identifies the Tight Junction Gene Zonula Occludens 2 as a Marker of Epithelioid “Pup” Smooth Muscle Cells and a Participant in Carotid Neointimal Formation
Authors: Adams Lawrence D. , Lemire Joan M. , Schwartz Stephen M.
Published: June 2011

Abstract
—An accumulation of evidence suggests that vascular smooth muscle is composed of cell subpopulations with distinct patterns of gene expression. Much of this evidence has come from serendipitous discoveries of genes marking phenotypically distinct aortic cultures derived from 12-day-old and 3-month-old rats. To identify more systematic differences, we isolated 40 genes at random from libraries of these 2 cultures and examined message expression patterns. To determine consistency of differential expression, we measured mRNA levels in 4 sets of cultures in 6 phenotypically distinct aortic cell clones and in balloon injured rat carotid arteries to determine the relevance of these differences in vitro to in vivo biology. The following 5 consistently differentially expressed genes were identified in vitro: zonula occludens 2 (ZO-2); peroxisome proliferator-activated receptor δ (PPARδ); secreted protein, acidic and rich in cysteine (SPARC); α1(I)collagen; and A2, an uncharacterized gene. We examined these 5 clones during carotid artery injury and an inconsistently differentially expressed clone Krox-24 because, as an early response transcription factor, it could be involved in the injury response. PPARδ, A2, and Krox-24 mRNAs were upregulated during the day after injury. ZO-2 and α1(I)collagen messages were modulated for up to a month, whereas SPARC message showed no consistent change. An analysis of ZO-2 and other tight junction genes indicates that tight junctions may play a role in smooth muscle biology. These data suggest that a systematic analysis of these libraries is likely to identify a very large number of differentially expressed genes. ZO-2 is particularly intriguing both because of this tight junction gene’s pattern of prolonged over-expression after injury and because of its potential role in determining the distinctive epithelioid phenotype of smooth muscle cells identified in rat and other species.
von Willebrand Factor, C-Reactive Protein, and 5-Year Mortality in Diabetic and Nondiabetic Subjects
Authors: Jager Agnes , van Hinsbergh Victor W. M. , Kostense Piet J. , Emeis Jef J. , Yudkin John S. , Nijpels Giel , Dekker Jacqueline M. , Heine Robert J. , Bouter Lex M. , Stehouwer Coen D. A.
Published: June 2011

Abstract
—Increased levels of von Willebrand factor (vWf) and C-reactive protein (CRP) predict cardiovascular mortality in selected populations. It is uncertain whether vWf and CRP predict mortality in a general population and whether vWf and CRP predict mortality through similar pathways. This study investigated the association of vWf and CRP with cardiovascular and all-cause mortality among diabetic and nondiabetic subjects. An age-, sex-, and glucose tolerance–stratified sample (n=631) of a population-based cohort aged 50 to 75 years was followed prospectively for 5 years. After 5 years of follow-up, 58 subjects had died (24 of cardiovascular causes). vWf (>1.56 IU/mL) and CRP (>2.84 mg/L) levels in the upper tertile were associated with, respectively, a 3- and 2-fold increase in cardiovascular mortality after adjustment for age, sex, and glucose tolerance status. Analyses in nondiabetic and diabetic subjects separately gave similar results. After further adjustment for hypertension, levels of HDL cholesterol and triglyceride, smoking habits, ischemic heart disease, and peripheral arterial disease, the relative risks (RRs) were 3.0 (95% CI 1.2 to 7.9) for vWf and 1.4 (95% CI 0.6 to 3.5) for CRP. When both vWf and CRP were included in the latter multivariate analysis, the RRs were 3.0 (95% CI 1.1 to 7.9) for vWf and 1.3 (95% CI 0.5 to 3.4) for CRP. The association between vWf and risk of cardiovascular mortality was independent of blood group (O versus non-O) and, moreover, similar among subjects with different blood groups. Repeating the analyses for all-cause mortality gave similar results for CRP. For vWf, the RR was 2.0 (95% CI 1.1 to 3.5) after adjustment for all other risk factors. Increased levels of vWf are independently associated with cardiovascular and all-cause mortality in both diabetic and nondiabetic subjects. The association between increased levels of CRP and cardiovascular mortality was partly explained by other risk factors. Mutual adjustment of vWf and CRP did not markedly change the results, favoring the hypothesis that vWf and CRP predict mortality through different pathways.
Differential Association of Common Carotid Intima-Media Thickness and Carotid Atherosclerotic Plaques With Parental History of Premature Death From Coronary Heart Disease
Authors: Zureik Mahmoud , Touboul Pierre-Jean , Bonithon-Kopp Claire , Courbon Dominique , Ruelland Isabelle , Ducimetière Pierre
Published: June 2011

Abstract
—Familial aggregation of coronary heart disease (CHD) has been reported in several studies. The specific underlying mechanisms and the relative contribution of atherosclerosis to the subsequent CHD events in subjects with family history are not well established. This study examined the association of parental history of premature death from CHD with ultrasound carotid measurements of atherosclerosis in a population of 1040 subjects aged 59 to 71 years. Ultrasound examination included measurements of intima-media thickness at the common carotid arteries (at sites free of plaques) and assessment of atherosclerotic plaques in the extracranial carotid arteries. Subjects who reported that 1 or both parents had sudden death or died of myocardial infarction before the age of 65 years were considered positive for parental history of premature death from CHD (n=53, 5.1%). The prevalence of atheromatous plaques was higher in subjects with history of premature death from CHD compared with those without history (41.5% versus 20.5%,
P
<0.001). Age- and sex-adjusted odds ratio of atheromatous plaques associated with parental history of premature death from CHD was 2.85 (95% confidence interval, 1.60 to 5.08;
P
<0.001). Multivariate adjustment for major known cardiovascular risk factors did not markedly alter the results (odds ratio, 2.70;
P
<0.002). In contrast, common carotid intima-media thickness was not associated with parental history of premature death from CHD (0.66±0.11 versus 0.66±0.12 mm,
P
=0.76). These findings were observed in both men and women. In conclusion, parental history of premature death from CHD is strongly associated with carotid plaques. Familial transmission of CHD risk does not seem to be specifically mediated by arterial wall thickening measured at sites free of plaques.