bluuebunny/crossref_metadata_2025 huggingface dataset:
Native LDL Increases Endothelial Cell Adhesiveness by Inducing Intercellular Adhesion Molecule–1
Authors: Smalley David M. , Lin Jane H.-C. , Curtis Michelle L. , Kobari Yukage , Stemerman Michael B. , Pritchard Kirkwood A.
Published: June 2011

AbstractNative LDL (n-LDL) increases human umbilical vein endothelial cell (EC) adherence of mononuclear cells. Such phenotypic changes suggest that n-LDL alters the usual expression of cell adhesion molecules to enhance the adhesive properties of the endothelium. To investigate n-LDL mechanisms governing adherence, ECs were exposed to n-LDL in concentrations up to 240 mg/dL for 2 and 4 days. n-LDL–treated ECs bound nearly threefold more phorbol myristate acetate (PMA)–stimulated U937 cells than control ECs but did not bind unstimulated U937 cells. Anti–intercellular adhesion molecule–1 (ICAM-1) antibodies blocked PMA-stimulated U937 cell binding to control and n-LDL–treated ECs by more than 80%, suggesting that increases in ICAM-1 may be involved in this increased adherence. Although increases in PMA-stimulated U937 cell binding developed with respect to time and concentration, statistically significant increases were achieved only when n-LDL concentrations exceeded 180 mg cholesterol/dL at day 4. n-LDL increased endothelial adherence of freshly isolated human monocytes more than twofold and neutrophils by almost twofold. Fluorescent-linked immunoassays revealed that n-LDL increased ICAM-1 protein expression by twofold, which corresponded with increased ICAM-1 message levels. n-LDL also appeared to increase E-selectin and vascular cell adhesion molecule–1 message levels, but these changes did not translate into statistically significant differences in protein levels. Taken together, these data indicate that n-LDL increases ICAM-1 expression to enhance the adhesive properties of the endothelium. Such perturbations in EC function likely represent a proinflammatory response to protracted n-LDL exposure and one of the early steps in atherogenesis.
Platelet Adhesion to Multimeric and Dimeric von Willebrand Factor and to Collagen Type III Preincubated With von Willebrand Factor
Authors: Wu Ya-Ping , van Breugel Hans H.F.I. , Lankhof Hanneke , Wise Robert J. , Handin Robert I. , de Groot Philip G. , Sixma Jan J.
Published: June 2011

Abstract
As part of a systematic study of platelet interaction with adhesive proteins under flow conditions, we studied platelet adhesion to multimeric and dimeric von Willebrand factor (vWF) coated to glass. vWF-dependent adhesion to collagen type III was studied for comparison. Adhesion to glass-coated vWF and vWF-mediated adhesion to collagen type III were in many respects similar. Both showed no decrease at increasing shear rates and a decline to 50% of maximum with a low-molecular-weight multimeric fraction. Adhesion to glass-coated vWF was partially inhibited by heparin and completely inhibited by prostaglandin I
2
and anti–glycoprotein (GP) Ib and anti–GPIIb-IIIa antibodies. vWF-dependent adhesion to collagen was not inhibited by heparin, was partially inhibited by anti–GPIIb-IIIa, and was completely inhibited by prostaglandin I
2
and anti-GPIb. Recombinant dimeric vWF was made by deletion of the propeptide and expression in Chinese hamster ovary cells. Adhesion was 50% of that with plasma vWF, and larger concentrations of dimeric vWF were required. Adhesion to dimeric vWF was optimal at 1500 s
−1
, with a gradual decrease at higher shear rates. We conclude that adhesion to collagen type III is strongly but not completely determined by the adhesive properties of vWF.
Plasma Fibrinogen Inhibits Platelet Adhesion in Flowing Blood to Immobilized Fibrinogen
Authors: Endenburg Silvia C. , Lindeboom-Blokzijl Laya , Zwaginga Jaap J. , Sixma Jan J. , de Groot Philip G.
Published: June 2011

Abstract
The influence of variations in plasma fibrinogen concentration on platelet adhesion to immobilized fibrinogen was investigated in a parallel-plate perfusion chamber. At a shear rate of 1600 s
−1
platelet adhesion decreased when increasing concentrations of purified fibrinogen were added to the plasma (IC
50
=1.5±0.2 g/L fibrinogen, n=24). Washed platelets reconstituted in a human albumin solution with red blood cells were more sensitive for soluble fibrinogen (IC
50
=0.4±0.1 g/L, n=5,
P
<.05). When platelet activation during circulation of the blood was minimized by using a single-passage perfusion system, an IC
50
of 2.0±0.2 g/L was found (n=9). To exclude the possibility that the inhibition of fibrinogen was caused by irreversible changes in the fibrinogen molecule during the purification procedure, normal plasma was mixed in different ratios with plasma from a patient with congenital afibrinogenemia. Under these conditions, the plasma fibrinogen IC
50
was 1.5±1.1 g/L. Absence of endogenous fibrinogen in the platelets of the patient resulted in an IC
50
of 1.2±0.5 g/L for plasma fibrinogen. These results demonstrate that increased plasma fibrinogen concentrations inhibit platelet adhesion to fibrinogen under flow.
Endothelial Cell Tyrosine Kinase Receptor and G Protein–Coupled Receptor Activation Involves Distinct Protein Kinase C Isoforms
Authors: Haller Hermann , Ziegler Wolfgang , Lindschau Carsten , Luft Friedrich C.
Published: June 2011

Abstract
Protein kinase C (PKC) is a family of serine/threonine protein kinase isoforms that is important to intracellular enzymes for both tyrosine kinase receptors and G protein–coupled receptors. However, which isoforms are linked to which class of receptors in endothelial cell signaling is not known. Moreover, the PKC isoforms in endothelial cells have not been thoroughly characterized. We tested the hypothesis that specific PKC isoforms are involved in different signaling pathways. PKC isoform expression was assessed by using reverse transcription polymerase chain reaction and Western blotting. The spatial distribution of PKC after stimulation of the cells with basic fibroblast growth factor (bFGF) and thrombin was examined by using confocal microscopy. Expression of PKC α, δ, ε, θ, and ζ was detectable on both the mRNA and protein levels. In resting cells, PKC δ and ζ were mostly distributed in the cytosol, while PKC α and ε were also present in the nucleus. Nuclear immunoreactivity of PKC α and ε increased significantly between passages 1 and 3. The phorbol ester TPA induced a rearrangement of PKC δ and a translocation of PKC α and ε to the nucleus. Treatment of endothelial cells with TPA for 24 hours caused PKC α, δ, and ε to disappear, while PKC ζ was not influenced by TPA. bFGF induced a rapid assembly of PKC α along cytosolic structures, followed by a translocation of the isoform toward the perinuclear region and into the nucleus. bFGF had a similar effect on PKC ε. In contrast, thrombin had a smaller effect on nuclear translocation of PKC α, did not influence PKC ε, and induced a rapid nuclear translocation of PKC ζ. Thus, tyrosine kinase receptor activation via bFGF induced a rapid association of PKC α and ε with nuclear structures, while activation of the G protein–coupled thrombin receptor increased mostly nuclear PKC ζ. The translocation of PKC isoforms into the nucleus by growth-promoting factors may be important for the induction of endothelial cell growth.
Apolipoprotein(a) Kringle IV Repeat Number Predicts Risk for Coronary Heart Disease
Authors: Kraft H.G. , Lingenhel A. , Köchl S. , Hoppichler F. , Kronenberg F. , Abe A. , Mühlberger V. , Schönitzer D. , Utermann G.
Published: June 2011

Abstract
A high plasma concentration of lipoprotein(a) [Lp(a)] has been suggested as a risk factor for coronary heart disease (CHD), but some recent prospective studies have questioned the significance of Lp(a). Lp(a) concentrations are determined to a large extent by the hypervariable apo(a) gene locus on chromosome 6q2.7, which contains a variable number of identical tandemly arranged transcribed kringle IV type 2 repeats. The number of these repeats correlates inversely with plasma Lp(a) concentration. We analyzed whether apo(a) gene variation (kringle IV repeat number) is associated with CHD. Apo(a) genotypes were determined by pulsed-field gel electrophoresis/genomic blotting in CHD patients who had undergone angiography (n=69) and control subjects matched for age, sex, and ethnicity (n=69) and were related to Lp(a) concentration, apo(a) isoform in plasma, and disease status. Apo(a) alleles with a low kringle IV copy number (<22) and high Lp(a) concentration were significantly more frequent in the CHD group (
P
<.001), whereas large nonexpressed alleles were more frequent in control subjects. The odds ratio for CHD increased continuously with a decreasing number of kringle IV repeats and ranged from 0.3 in individuals with >25 kringle IV repeats on both alleles to 4.6 in those with <20 repeats on at least one allele. This provides direct genetic evidence that variation at the apo(a) gene locus, which determines Lp(a) levels, is also a determinant of CHD risk.
Gene Expression of Acyl Coenzyme A
Authors: Wang Hongxing , Germain Sandra J. , Benfield Pamela P. , Gillies Peter J.
Published: June 2011

Abstract
The gene expression and enzyme kinetics of acyl coenzyme A:cholesterol acyltransferase (ACAT) were investigated in human monocytes, macrophages, and foam cells. Northern blot analysis using a 1.65-kb coding region of human ACAT cDNA as the probe showed that each of the cell types exhibited four mRNA transcripts. The levels of the 4.2- and 3.7-kb ACAT transcripts were three- and sixfold higher, respectively, in macrophages than monocytes. These transcripts were expressed at the same high levels after conversion of macrophages to foam cells. In contrast, the 6.3- and 4.4-kb transcripts for ACAT were expressed at a relatively constant level in all three cell types. The expression of mRNA for glyceraldehyde phosphate dehydrogenase, the control gene in this study, was also expressed at a constant level in each of the cell types. The increase in ACAT mRNA was accompanied by changes in the kinetic properties of the enzyme. Specifically, there was a 14-fold increase in V
max
and a 71% decrease in
K
m
with respect to oleoyl coenzyme A. Although not definitive, the concomitant changes in mRNA and V
max
strongly suggest that the amount of ACAT protein increases upon conversion of monocytes to macrophages. The data show that ACAT in monocytes can be regulated by both substrate and gene expression.
Ultrasound Morphology Classification of the Arterial Wall and Cardiovascular Events in a 6-Year Follow-up Study
Authors: Belcaro Gianni , Nicolaides Andrew N. , Laurora Giuseppe , Cesarone Maria Rosaria , De Sanctis Mariateresa , Incandela Lucrezia , Barsotti Antonio
Published: June 2011

A 6-year follow-up based on an arterial morphology classification defined with an ultrasound assessment of carotid and femoral artery bifurcations was conducted on 2322 asymptomatic subjects. Four morphology classes were considered. When 2000 subjects (86% of total subjects; 1124 males, 876 females) completed a 6-year follow-up, the study was terminated. At 6 years, no cardiovascular events were observed in subjects who were in class I (80.05% of the population sample) at inclusion; there were 69 events in classes II, III, and IV (19.95% of the population; incidence, 17.3%); 59 events, including the five deaths, occurred in classes III and IV (10.85% of the population), producing an event incidence of 27.2%. The increased event rate in classes II, III, and IV was significant (log-rank test;
P
<.05,
P
<.025, and
P
<.025, respectively). Thus, the arterial morphology classification identified 19.95% of the population (subjects in classes II, III, and IV) in which all events occurred. There was a higher (
P
<.05) rate of progression of altered arterial morphology in 6 years in classes III (26.5% of subjects progressed) and IV (41.9% progressed) than in classes I and II. The total number of cigarette-years was higher (
P
<.05) in classes II, III, and IV than in class I. In conclusion, the ultrasound-based arterial classification was useful in selecting from the population sample 80.05% of subjects (class I) who remained event-free for 6 years. All events occurred in class II, III, and IV subjects (19.95%), and all five deaths (0.25% of the population) occurred in classes III and IV (10.85% of the sample).
Angiotensin II-Induced Progression of Neointimal Thickening in the Balloon-Injured Rat Carotid Artery Is AT
1
Receptor Mediated
Authors: van Kleef Ellen M. , Fingerle Jürgen , Daemen Mat J.A.P.
Published: June 2011

To investigate the relative importance of AT
1
and AT
2
receptors in angiotensin II (Ang II)-induced restimulation of neointimal smooth muscle cell (SMC) DNA synthesis and increased neointimal cross-sectional area (CSA), male Wistar rats were subcutaneously infused for 2 weeks with Ang II and losartan, an AT
1
receptor antagonist, or Ang II and
PD123319
, an AT
2
receptor antagonist, during the third and fourth week after balloon injury of the left common carotid artery. Concomitantly, all rats received 5-bromo-2′-deoxyuridine to label DNA-synthesizing SMCs. Neointimal CSAs and SMC DNA synthesis were compared with control groups that received Ang II, 0.9% NaCl, losartan, or PD123319. Systolic blood pressure (SBP) was measured at different times during the infusion. Ang II induced an increase in SBP that was significantly different from the SBP in the NaCl group. Infusion of Ang II together with losartan reduced the Ang II-induced increase in SBP to levels comparable with those obtained in the NaCl group. Infusion of Ang II+
PD123319
caused an increase in SBP that was comparable with the increase in SBP of the Ang II group and significantly different from the SBP of the NaCl group. Infusion of losartan or
PD123319
alone did not affect SBP. Ang II significantly enhanced neointimal CSA (47%,
P
<.05) compared with the control group infused with NaCl. Losartan significantly reduced Ang II-induced neointimal thickening (neointimal CSA, −37%,
P
<.05). Infusion of
PD123319
together with Ang II did not affect Ang II-induced neointimal thickening. Losartan or
PD123319
alone did not reduce neointimal thickening, since the neointimal CSAs in these groups did not differ from the neointimal CSA of the NaCl group. Comparable effects were found for SMC DNA synthesis in the neointima. Ang II infusion increased neointimal SMC DNA synthesis. Addition of losartan reduced the fraction of DNA-synthesizing neointimal SMCs from 23.7±2.1% in the Ang II group to 12.8±1.8% in the Ang II+losartan group, whereas the labeling fraction in the neointima remained 26.6±3.1% in the Ang II+
PD123319
group. The labeling fractions in the neointimas of the groups that received losartan or
PD123319
alone did not differ from the labeling fraction in the NaCl group. These data indicate that AT
1
but not AT
2
receptors mediate the progression of neointimal thickening induced by delayed application of Ang II in the injured left carotid artery in the rat. Furthermore, these data suggest that AT
1
and AT
2
receptors are not involved in the regulation of normal growth of a neointima in the third and fourth week after balloon injury.
Circumferential Stress and Matrix Metalloproteinase 1 in Human Coronary Atherosclerosis
Authors: Lee Richard T. , Schoen Frederick J. , Loree Howard M. , Lark Michael W. , Libby Peter
Published: June 2011

Atherosclerotic plaque rupture may occur when regions of weakened extracellular matrix are subjected to increased mechanical stresses. Since collagen is a major determinant of extracellular matrix strength, enzymes that degrade collagen may play an important role in destabilizing the atherosclerotic lesion. To test the hypothesis that matrix metalloproteinase 1 (interstitial collagenase, or MMP-1), which initiates degradation of fibrillar collagens, colocalizes with increased stress in the fibrous cap of the atherosclerotic lesion, 12 unruptured human coronary lesions were studied. Finite-element analysis was used to determine the distribution of stress in the lesion, with estimates of material properties from previous measurements of human tissues. A computerized image analysis system was used to determine the distribution of immunoreactive MMP-1 within the fibrous tissue of the lesion. There was a significant correlation between immunoreactive MMP-1 and circumferential tensile stress in the fibrous cap within a given lesion (median Spearman rank correlation coefficient, .36; interquartile range, −.02 to .81;
P
<.02). Within a given lesion, the highest-stress region had twofold greater MMP-1 expression than the lowest-stress regions. In unruptured human atherosclerotic coronary lesions, overexpression of MMP-1 is associated with increased circumferential stress in the fibrous plaque. Degradation and weakening of the collagenous extracellular matrix at these critical high-stress regions may play a role in the pathogenesis of plaque rupture and acute ischemic syndromes.
Suppression of Atherosclerotic Changes in Cholesterol-Fed Rabbits Treated With an Oral Inhibitor of Neutral Endopeptidase 24.11 (EC 3.4.24.11)
Authors: Kugiyama Kiyotaka , Sugiyama Seigo , Matsumura Toshiyuki , Ohta Yasutaka , Doi Hideki , Yasue Hirofumi
Published: June 2011

Neutral endopeptidase 24.11 (NEP), widely distributed in the body, hydrolyzes and inactivates a number of endogenous vasoactive peptides, some of which could alter various functions of cells present in the arterial wall. Recently NEP has been found to exist in the vascular endothelium. The aim of this study was to assess the influence of chronic NEP inhibition by daily administration of UK79300 (candoxatril), an orally active NEP inhibitor (NEPI), on the development of atherosclerotic changes in high-cholesterol-fed rabbits. Male New Zealand White rabbits were fed for 8 weeks as follows: normal rabbit diet (Normal, n=15), 1.5% cholesterol diet (Cholesterol, n=15), or 1.5% cholesterol diet containing NEPI (20 mg·kg
−1
·d
−1
) (Cholesterol+NEPI, n=15). At the end of the dietary period, NEPI treatment was found to suppress the surface area of the aorta covered by plaques (% surface area: Cholesterol, 59±6 versus Cholesterol+NEPI, 36±7,
P
<.01) and decreased contents of cholesterol and cholesterol esters in the aortas. NEPI also reduced plasma total cholesterol by 27% of Cholesterol rabbits (1781±130 mg/dL). The endothelial function, estimated by the endothelium-dependent relaxation of the isolated aortas in response to acetylcholine, was preserved in Cholesterol+NEPI rabbits compared with that in Cholesterol rabbits. NEP enzymatic activities in plasma and the particulate fraction of the homogenates from the aortas in Cholesterol rabbits were both increased, 3.1- and 3.9-fold, respectively, above those in Normal rabbits, but the activities in Cholesterol+NEPI rabbits were significantly lower than those in Cholesterol rabbits. UK73967, an active form of UK79300, or phosphoramidon partly reversed the atherosclerotic impairment of relaxation of the isolated thoracic aortic rings from Cholesterol rabbits in response to exogenous additions of C-type natriuretic peptide (CNP) and substance P, which are NEP substrates known to exist endogenously in the vascular endothelium. The results suggest that the increased NEP activity plays a significant role in atherogenesis, and NEPIs might be therapeutically useful in the prevention of atherosclerosis. Reduction of plasma cholesterol and suppression of degradations in the arteries of endogenously released CNP, substance P, or possibly other kinins known to have anti-atherosclerotic actions may at least partially contribute to the inhibitory effects of NEPIs on atherosclerotic changes.
Apolipoprotein E Polymorphism in American Indians and Its Relation to Plasma Lipoproteins and Diabetes
Authors: Kataoka Shinkuro , Robbins David C. , Cowan Linda D. , Go Oscar , Yeh Jeunliang L. , Devereux Richard B. , Fabsitz Richard R. , Lee Elisa T. , Welty Thomas K. , Howard Barbara V.
Published: June 2011

Apo E is an important genetic factor in the development of cardiovascular disease, which is the leading cause of death among American Indians. We investigated the occurrence of the apo E alleles and the relation between apo E polymorphism and blood lipoproteins and apoproteins in members of 13 American Indian communities in three geographic areas. The frequencies of the ε2 alleles in American Indians are significantly lower than those in white Americans, with the lowest frequencies of ε2 in American Indians who reside in Arizona. Levels of LDL cholesterol and apo B were highest in those with ε4 and lowest in those with ε2. Concentrations of HDL cholesterol and apo A-I, however, tended to be lowest in ε4 and highest in ε2. Concentrations of total and VLDL triglycerides were lowest in the ε3 group and higher in groups ε2 and ε4. Differences in concentrations of LDL cholesterol, HDL cholesterol, apo B, and apo A-I with apo E polymorphism were greater in women than in men, and differences in total and VLDL triglyceride concentrations by apo E phenotype were greater in men. Relations of total and VLDL triglycerides with apo E phenotype were stronger in women after menopause. In addition, differences in nearly all lipid and apoprotein concentrations between postmenopausal women and premenopausal women were greater if they had ε2. Relations between apo E phenotype and lipoproteins were seen in individuals with diabetes mellitus as well as in nondiabetics. Apo E was significantly related to glucose control in diabetic women; those with ε3 had higher glucose and hemoglobin A
1C
concentrations. Our findings show that (1) American Indians have low frequencies of apo ε2; (2) apo E phenotype can influence levels of VLDL, LDL, HDL, apo B, and apo A-I; (3) the associations of apo E polymorphisms with lipid parameters differ between men and women; and (4) the associations in women of apo E polymorphisms with lipid parameters are modified by menopausal status.
Medial Artery Calcification
Authors: Lehto Seppo , Niskanen Leo , Suhonen Matti , Rönnemaa Tapani , Laakso Markku
Published: June 2011

Medial artery calcification (MAC) is a nonobstructive condition leading to reduced arterial compliance that is commonly considered as a nonsignificant finding. The aim of our study was to investigate the predictive value of MAC in relation to 7-year cardiovascular mortality, coronary heart disease (CHD) events, stroke, and lower extremity amputation in 1059 patients (581 men and 478 women) with non–insulin-dependent diabetes mellitus (NIDDM). At baseline radiologically detectable MAC in femoral arteries was found in 439 patients (41.5%) and intimal-type calcification in 310 diabetic patients (29.3%). The mean fasting plasma glucose at baseline was somewhat higher in women and the duration of diabetes somewhat longer in patients with MAC than in those without, but otherwise the presence of MAC was unrelated to conventional cardiovascular risk factors. During the follow-up 305 diabetic patients died: 208 from cardiovascular disease, 158 from CHD, and 34 from stroke. Furthermore, 58 NIDDM patients underwent their first lower extremity amputation. MAC was a strong independent predictor of total (risk factor–adjusted odds ratio and 95% confidence interval: 1.6; 1.2, 2.2), cardiovascular (1.6; 1.1, 2.2), and CHD (1.5; 1.0, 2.2) mortality, and it was also a significant predictor of future CHD events (fatal or nonfatal myocardial infarction), stroke, and amputation. This relationship was observed regardless of glycemic control and known duration of NIDDM. MAC is a strong marker of future cardiovascular events in NIDDM unrelated to cardiovascular risk factors, supporting the hypothesis that reduced arterial elasticity could lead to clinical manifestations of diabetic macroangiopathy.
Smooth Muscle DNA Replication in Response to Angiotensin II Is Regulated Differently in the Neointima and Media at Different Times After Balloon Injury in the Rat Carotid Artery
Authors: deBlois D. , Viswanathan M. , Su J.E. , Clowes A.W. , Saavedra J.M. , Schwartz S.M.
Published: June 2011

We have reported that angiotensin II (Ang II) infusion to rats during the third and fourth weeks after vascular injury stimulates DNA replication in a larger proportion of smooth muscle cells (SMCs) in the arterial neointima than in the underlying media or the normal arterial media. Whether this increased responsiveness to Ang II is a transient or stable property of neointimal cells after vascular injury remained unclear. The present study examined smooth muscle DNA replication in response to Ang II infusion (250 ng·kg
−1
·min
−1
for 2 weeks) at 3 to 4, 9 to 10, or 27 to 28 weeks after balloon injury to the rat carotid artery. Control rats received Ringer's lactate. BrdU (0.8 mg·kg
−1
·d
−1
) was coinfused to label replicating DNA. The increased replicative response to Ang II in the neointima versus the normal arterial media did not persist beyond the period of rapid lesion growth shortly after injury, even in neointimal areas without endothelial regeneration. By 9 to 10 weeks after injury, replication frequencies were comparable in the neointima and the normal arterial wall. In the presence of a regenerated endothelium, neointimal DNA replication was lowered but not abolished. After the early period, however, the most marked difference may be the loss of ability of medial SMCs to respond mitogenically to systemic Ang II. As a consequence, Ang II–induced DNA replication in injured arteries was greater in the neointima than in the underlying media at all times studied after injury. DNA replication levels correlated with AT
1
receptor levels in the injured artery neointima but not media, as shown by receptor binding in vascular sections at 3 and 10 weeks after injury. The growth response to systemic Ang II is differentially regulated in adjacent smooth muscle layers in the injured arterial wall in vivo via mechanisms that include, but are not restricted to, the regulation of AT
1
receptor expression in SMCs.
Population Correlates of Coagulation Factor VII
Authors: Scarabin Pierre-Yves , Vissac Anne-Marie , Kirzin Jean-Michel , Bourgeat Pierre , Amiral Jean , Agher Rachid , Guize Louis
Published: June 2011

Factor VII coagulant activity (FVIIc) has been found to be related to cardiovascular risk factors and may be an independent predictor of coronary heart disease (CHD). Whether these associations are due to changes in FVII activation rather than FVII concentration remain unclear. Therefore, we investigated the relationships between activated factor VII (FVIIa) and CHD risk factors in healthy subjects (336 men and 348 women) aged 25 to 64 years. In addition to direct quantitation of FVIIa by use of a recombinant, truncated tissue factor, FVIIc and factor VII antigen (FVII:Ag) levels were measured by standard procedures. There were highly significant correlations between the three techniques of FVII assay (
r
>+.55). Plasma FVIIc and FVIIa levels increased with age in both sexes, but the rate of rise was significantly greater in women than men. At younger ages, mean values of FVIIc and FVIIa were significantly lower in women than men, whereas at older ages the reverse was observed. After adjustment for age, postmenopausal women had significantly higher mean levels of FVIIc and FVIIa than did premenopausal women. Hormone replacement therapy significantly reversed the rise in FVIIc in postmenopausal women, and a similar trend in FVIIa was also observed. Age-, sex-, and menopause-related changes in FVIIc were partly explained by a higher proportion of fully active FVII molecules, as indicated by significant differences in the FVIIa-to-FVII:Ag ratio. Oral contraceptive use was associated with high FVIIc levels, and this effect was mainly due to an increase in FVII:Ag. Levels of FVIIa were positively correlated with serum cholesterol concentrations in both sexes. There were no strong associations between FVIIa levels and other CHD risk factors, including smoking habits, alcohol consumption, blood pressure, obesity, glucose, triglycerides, and serum lipoprotein(a) concentrations. Multiple regression analysis showed independent effects of age and cholesterol levels on FVIIa in men, whereas age and menopausal status were the main predictors of FVIIa in women. Our results show that FVII activation is associated with CHD risk factors. These findings are consistent with a possible role for FVII in the pathogenesis of CHD. Furthermore, our data suggest that the dramatic rise in CHD incidence in postmenopausal women as well as the cardioprotective effect of estrogen may be mediated through FVII and blood coagulation.
Apolipoprotein E Polymorphism and LDL Size in a Biethnic Population
Authors: Haffner Steven M. , Stern Michael P. , Miettinen Heikki , Robbins David , Howard Barbara V.
Published: June 2011

Polymorphisms in the apolipoprotein E (apoE) phenotype (especially E
4
) are associated with increased cardiovascular risk and particularly with increased concentrations of LDL cholesterol. Little is known, however, about whether alterations in LDL size are associated with the apoE
4
phenotype. LDL size was determined by gradient gel electrophoresis, and apoE phenotype was determined by isoelectric focus in 337 nondiabetic subjects from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors in Mexican Americans and non-Hispanic whites. ApoE
4
was associated not only with increases in LDL cholesterol concentrations but also with decreased LDL size. After adjustment for age, sex, body mass index, waist-to-hip ratio, triglyceride, HDL cholesterol, fasting insulin, and diabetic status, the apoE phenotype remained significantly related to LDL size (Å) in both men (apoE
23
, 260.0; apoE
33
, 256.3; and apoE
34
, 252.6;
P
=.01) and women (apoE
23
, 261.7; apoE
33
, 257.9; and apoE
34
, 256.7,
P
=.045). Variations in apoE phenotype are associated not only with changes in the absolute concentration of LDL cholesterol but also with changes in its composition. These changes are only partly explained by associations of apoE with insulin, triglyceride, and HDL cholesterol.
Effects of Intravenous Infusion of Lipid-Free Apo A-I in Humans
Authors: Nanjee M.N. , Crouse J.R. , King J.M. , Hovorka R. , Rees S.E. , Carson E.R. , Morgenthaler J.-J. , Lerch P. , Miller N.E.
Published: June 2011

Apolipoprotein (apo) A-I is the principal protein component of the plasma high density lipoproteins (HDLs). Tissue culture studies have suggested that lipid-free apo A-I may, by recruiting phospholipids (PLs) and unesterified cholesterol from cell membranes, initiate reverse cholesterol transport and provide a nidus for the formation, via lipid-poor, pre-β–migrating HDLs, of spheroidal α-migrating HDLs. Apo A-I has also been shown to inhibit hepatic lipase (HL) and lipoprotein lipase (LPL) in vitro. To further study its functions and fate in vivo, we gave lipid-free apo A-I intravenously on a total of 32 occasions to six men with low HDL cholesterol (30 to 38 mg/dL) by bolus injection (25 mg/kg) and/or by infusion over 5 hours (1.25, 2.5, 5.0, and 10.0 mg·kg
−1
·h
−1
). The procedure was well tolerated: there were no clinical, biochemical, or hematologic changes, and there was no evidence of allergic, immunologic, or acute-phase responses. The 5-hour infusions increased plasma total apo A-I concentration in a dose-related manner by 10 to 50 mg/dL after which it decreased, with a half-life of 15 to 54 hours. Coinfusion of Intralipid reduced the clearance rate. The apparent volume of distribution exceeded the known extracellular space in humans, suggesting extensive first-pass clearance by one or more organs. No apo A-I appeared in the urine. Increases in apo A-I mass were confined to the pre-β region on crossed immunoelectrophoresis of plasma and to HDL-size particles on size exclusion chromatography. Increases were recorded in HDL PL, but not in HDL unesterified or esterified cholesterol. Increases also occurred in LDL PL and in very low density lipoprotein cholesterol, triglycerides, and PL but not in plasma total apo B concentration. These results can all be explained by combined inhibition of HL and LPL activities. Owing to the effects that this would have had on HDL metabolism, no conclusions can be drawn from these data about the role of lipid-free apo A-I in the removal of PL and cholesterol from peripheral tissues in humans. The kinetic data suggest that the fractional catabolic rate of lipid-free apo A-I exceeds that of spheroidal HDLs and is reduced in the presence of surplus PL.
Isolated Low HDL Cholesterol As a Risk Factor for Coronary Heart Disease Mortality
Authors: Goldbourt Uri , Yaari Shlomit , Medalie Jack H.
Published: June 2011

For the purpose of screening individuals at high risk for coronary heart disease (CHD), serum total cholesterol (TC) of 5.2 mmol/L has been set as a value dividing “desirable” from intermediate high or elevated levels, and HDL cholesterol (HDL-C) <0.9 mmol/L has been labeled as abnormally low, implying high CHD risk. It has been conjectured that low HDL-C poses no risk in the absence of elevated LDL cholesterol or TC. To assess the risk of CHD-free men with “isolated low HDL-C,” ie, abnormally low HDL-C with desirable TC, we examined the CHD and all-cause mortality of some 8000 Israeli men aged 42 years and older during 1965 through 1986. Men with isolated low HDL-C represented one sixth of the cohort. CHD mortality among these men was 36% higher (age adjusted) than in counterparts with desirable TC, of which >0.9 mmol/L was contained in the high-density fraction. In men with TC>5.2 mmol/L, abnormally low HDL-C was associated with a virtually identical CHD mortality risk ratio, 38%. These findings persisted after adjustment for multiple CHD risk factors. The excess CHD risk associated with isolated low HDL-C appeared particularly increased in men with diabetes mellitus, whose death rate was 65% higher than in diabetics with HDL-C >0.9 mmol/L. A second subgroup result was consistent with equal CHD mortality risk among men in the “desirable” TC range, with or without low HDL-C, if systolic blood pressure was >160 mm Hg. These are post hoc findings, and hypotheses arising from these observations would require independent examination. Total mortality was not increased in men with isolated low HDL-C compared with men who had HDL-C <0.9 mmol/L and TC >5.2 mmol/L at baseline. These results indicate that an increased risk of CHD death is associated with abnormally low HDL-C for cholesterol ranges both below and above 5.2 mmol/L. For the individual, therefore, the risk is multiplied by the same amount regardless of TC. Quitting smoking, increasing physical activity, and decreasing body weight would all contribute to raise HDL-C in individuals of most or all age groups. When examined from a community perspective, the results are consistent with a relatively low population-attributable fraction among CHD-free men. This would tend to support the recommended practice of considering a TC level of 5.2 mmol/L (200 mg/dL) as a threshold for further evaluation in screened individuals without manifest CHD.
Platelet Integrin α
IIb
β3 (GPIIb-IIIa) Is Not Implicated in the Binding of LDL to Intact Resting Platelets
Authors: Pedreño Javier , Fernández Rosa , Cullaré Cristina , Barceló Antonia , Elorza Miguel Angel , de Castellarnau Conxita
Published: June 2011

It has been suggested that the fibrinogen receptor (glycoprotein [GP] IIb-IIIa or platelet integrin α
IIb
β
3
) could be the binding site for low-density lipoprotein (LDL); however, recent data do not support this. Furthermore, GPIIb and not the GPIIb-IIIa complex is the main binding protein for lipoprotein(a) [Lp(a)]. In the present study, we have investigated the interaction between Lp(a) particles and platelet LDL binding sites and whether platelet integrin α
IIb
β
3
is implicated. Displacement experiments showed that
125
I-LDL binding to intact resting platelets was inhibited with the same apparent affinity by both unlabeled LDL and apolipoprotein(a)-free lipoprotein particles [Lp(a)
−
, an LDL-like particle prepared from Lp(a)]. Hill coefficients for displacement curves suggested that a single set of binding sites was involved. In contrast, both native and oxidized Lp(a) particles were unable to inhibit platelet LDL binding. Furthermore, platelets bound
125
I-Lp(a)
−
particles to a class of saturable binding sites numbering approximately 1958±235 binding sites per platelet with a dissociation constant (
K
d
) of 48.3±12×10
−9
mol/L. These values were similar to those obtained for LDL. In contrast to Lp(a), evidence indicates that platelet integrin α
IIb
β
3
was not involved in the interaction of LDL and intact resting platelets. First, specific ligands for platelet integrin α
IIb
β
3
, such as fibrinogen, vitronectin, and fibronectin, were unable to inhibit the binding of LDL to intact resting platelets. Second, similar LDL binding characteristics (
K
d
and B
max
values) were found in platelets from control subjects and patients with type I and type II Glanzmann's thrombasthenia, characterized by total and partial lack of GPIIb-IIIa and fibrinogen, respectively. Third, polyclonal antibodies against the GPIIb-IIIa complex (edu-3 and 5B12), human antiserums against platelet alloantigens (anti-Bak
a/B
and anti-PL
A1/2
), anti-integrin subunits (anti-α
v
and anti-β
3)
, and a wide panel of monoclonal antibodies (mAbs) against well-known epitopes of GPIIb (M3, M4, M5, M6, and M95-2b) and GPIIIa (P23-7, P33, P37, P40, and P97) did not affect platelet LDL binding. Finally, in contrast to the proaggregatory effect of native and oxidized LDL, both native and oxidized Lp(a) particles caused a significant dose-dependent decrease of collagen-induced platelet aggregation. In conclusion, we demonstrate that neither the GPIIb-IIIa complex nor GPIIb and GPIIIa individually are membrane binding proteins for LDL on intact resting platelets. Lp(a) particles do not interact with platelet LDL binding sites, and their biological response is clearly different from that of LDL.
Inhibition of Collagen Synthesis, Smooth Muscle Cell Proliferation, and Injury-Induced Intimal Hyperplasia by Halofuginone
Authors: Nagler Arnon , Miao Hua-Quan , Aingorn Helena , Pines Mark , Genina Olga , Vlodavsky Israel
Published: June 2011

Proliferation of vascular smooth muscle cells (SMCs) and accumulation of extracellular matrix (ECM) components within the arterial wall in response to local injury are important etiologic factors in vascular proliferative disorders such as arteriosclerosis and restenosis after angioplasty. Fibrillar and nonfibrillar collagens are major constituents of the ECM that modulate cell shape and proliferative responses and thereby contribute to the pathogenesis of intimal hyperplasia. Halofuginone, an anticoccidial quinoazolinone derivative, inhibits collagen type I gene expression. We investigated the effect of halofuginone on (1) proliferation of bovine aortic endothelial cells and SMCs derived from the same specimen and maintained in vitro, (2) ECM deposition and collagen type I synthesis and gene expression, and (3) injury-induced intimal hyperplasia in vivo. DNA synthesis and proliferation of vascular SMCs in response to serum or basic fibroblast growth factor were abrogated in the presence of as little as 0.1 μg/mL halofuginone; this inhibition was reversible upon removal of the compound. Under the same conditions, halofuginone exerted a relatively small antiproliferative effect on the respective vascular endothelial cells. Halofuginone also inhibited the synthesis and deposition of ECM components by vascular SMCs as indicated both by a substantial reduction in the amount of sulfated proteoglycans and collagen type I synthesis and gene expression. Local administration of halofuginone in the rabbit ear model of crush injury–induced arterial intimal hyperplasia resulted in a 50% reduction in intimal thickening as measured by a morphometric analysis of the neointima/media ratio. The differential inhibitory effect of halofuginone on vascular SMCs versus endothelial cells, its inhibition of ECM deposition and collagen type I synthesis, and its ability to attenuate injury-induced intimal hyperplasia may place halofuginone alone or in combination with other antiproliferative compounds as a potential candidate for prevention of arterial stenosis and accelerated atherosclerosis.
Determinants of Plasma HDL-Cholesterol in Hypertriglyceridemic Patients
Authors: Tato Federico , Vega Gloria L. , Grundy Scott M.
Published: June 2011

Hypertriglyceridemic patients commonly have low levels of HDL cholesterol. Elevated triglycerides per se may be one cause of low HDL levels, but other factors also may be involved. The current study was designed to define the role of cholesterol-ester transfer protein (CETP) in causation of a low HDL cholesterol in hypertriglyceridemic patients; in addition other factors—lecithin cholesterol acyl transferase (LCAT), hepatic triglyceride lipase (HTGL), and lipoprotein lipase (LPL)—were examined. Plasma activities of CETP and LCAT were measured in 137 male patients with moderate hypertriglyceridemia (plasma triglycerides [TGs] 200 to 500 mg/dL and LDL cholesterol <160 mg/dL). Results were compared with those from 50 normolipidemic men of similar age and body habitus. In addition, lipase activities in postheparin plasma were measured in 118 of the subjects with hypertriglyceridemia. The activities of CETP and LCAT were 17% (
P
<.01) and 7% (
P
<.05), respectively, higher in the hypertriglyceridemic group than in control subjects. By stepwise regression analysis CETP appeared to contribute 15.2% and LCAT 9.8% to variation in HDL-cholesterol levels. Activities of LPL and HTGL together contributed an additional 14.1% to HDL-cholesterol variation. In contrast, levels of plasma TG accounted for only 5.4% of the variation. There were no differences in relative contributions of these parameters in patients with and those without coronary heart disease. This study indicates that several factors contribute to the variation in HDL-cholesterol levels in hypertriglyceridemic patients, and five factors—CETP, LCAT, HTGL, LPL, and triglyceride levels—account for almost half of this variation.
Excess Prevalence of Fasting and Postmethionine-Loading Hyperhomocysteinemia in Stable Renal Transplant Recipients
Authors: Bostom Andrew G. , Gohh Reginald Y. , Tsai Michael Y. , Hopkins-Garcia Bette J. , Nadeau Marie R. , Bianchi Lisa A. , Jacques Paul F. , Rosenberg Irwin H. , Selhub Jacob
Published: June 2011

Abstract
Hyperhomocysteinemia, either fasting or after methionine loading, may contribute to the increased incidence of cardiovascular disease events experienced by renal transplant recipients. Limited data are available on fasting homocysteine (Hcy) levels, and none on postmethionine-loading Hcy levels, in these patients. We assessed the prevalence and potential determinants of fasting and postmethionine-loading hyperhomocysteinemia in 29 stable renal transplant recipients and 58 age- and sex-matched, population-based controls free of renal disease with serum creatinine levels of 1.5 mg/dL or less. Total (t) plasma Hcy was determined fasting and 2 hours after methionine loading, along with fasting determinations of the B-vitamin cofactors/substrates for Hcy metabolism, ie, pyridoxal 5′-phosphate, B-12, and folate and serum creatinine. Geometric mean fasting (18.1 versus 9.8 μM,
P
<.001) and postmethionine-loading increase (22.0 versus 15.2,
P
=.001) in tHcy levels were significantly greater in the renal transplant recipients, as were the prevalence odds (with 95% confidence intervals) for fasting [14.8 (3.4-64.7)], postmethionine loading [6.9 (1.5-32.8)], combined fasting and postmethionine-loading [18.0 (2.3-142.1)] hyperhomocysteinemia, and inadequate circulating folate [4.2 (1.1-16.5)] or pyridoxal 5′-phosphate [3.2 (0.9-11.0) status. Correlation analyses suggested important potential relationships between creatinine and both fasting (+0.64,
P
<.001) and postmethionine-load increase (+0.38,
P
=.045) in tHcy, folate and fasting (−0.41,
P
=.025) tHcy, and pyridoxal 5′-phosphate and postmethionine-loading increase (−0.33,
P
=.091) in tHcy. We conclude that there is an excess prevalence of fasting and postmethionine-loading hyperhomocysteinemia in stable renal transplant recipients. Renal function is related to both fasting and postmethionine loading-hyperhomocysteinemia, inadequate folate status is associated with fasting hyperhomocysteinemia, and inadequate vitamin B-6 status may be related to postmethionine-loading hyperhomocysteinemia in this patient population.
Lovastatin Decreases De Novo Cholesterol Synthesis and LDL Apo B-100 Production Rates in Combined-Hyperlipidemic Males
Authors: Cuchel Marina , Schaefer Ernst J. , Millar John S. , Jones Peter J.H. , Dolnikowski Gregory G. , Vergani Carlo , Lichtenstein Alice H.
Published: June 2011

Abstract
The effect of lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, on the kinetics of de novo cholesterol synthesis and apolipoprotein (apo) B in very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL) was investigated in five male patients with combined hyperlipidemia. Subjects were counseled to follow a Step 2 diet and were treated with lovastatin and placebo in randomly assigned order for 6-week periods. At the end of each experimental period, subjects were given deuterium oxide orally and de novo cholesterol synthesis was assessed from deuterium incorporation into cholesterol and expressed as fractional synthesis rate (C-FSR) and production rate (C-PR). Simultaneously, the kinetics of VLDL, IDL, and LDL apo B-100 were studied in the fed state using a primed-constant infusion of deuterated leucine to measure fractional catabolic rates (FCR) and production rates (PR). Drug treatment resulted in significant decreases in total cholesterol (−29%), VLDL cholesterol (−40%), LDL cholesterol (−27%), and apo B (−16%) levels and increases in HDL cholesterol (+13%) and apolipoprotein (apo) A-I (+11%) levels. Associated with these plasma lipoprotein responses was a significant reduction in both de novo C-FSR (−40%;
P
=.04) and C-PR (−42%;
P
=.03). Treatment with lovastatin in these patients had no significant effect on the FCR of apoB-100 in VLDL, IDL, or LDL, but resulted in a significant decrease in the PR of apoB-100 in IDL and LDL. Comparing the kinetic data of these patients with those of 10 normolipidemic control subjects indicates that lovastatin treatment normalized apoB-100 IDL and LDL PR. The results of these studies suggest that the declines in plasma lipid levels observed after treatment of combined hyperlipidemic patients with lovastatin are attributable to reductions in the C-FSR and C-PR of de novo cholesterol synthesis and the PR of apoB-100 containing lipoproteins. The decline in de novo cholesterol synthesis, rather than an increase in direct uptake of VLDL and IDL, may have contributed to the decline in the PR observed.
Homocyst(e)ine and Risk of Cardiovascular Disease in the Multiple Risk Factor Intervention Trial
Authors: Evans Rhobert W. , Shaten B. Jessica , Hempel John D. , Cutler Jeffrey A. , Kuller Lewis H.
Published: June 2011

AbstractA nested case-control study was undertaken involving men participating in the Multiple Risk Factor Intervention Trial (MRFIT). Serum samples from 712 men, stored for up to 20 years, were analyzed for homocyst(e)ine. Cases involved nonfatal myocardial infarctions (MIs), identified through the active phase of the study, which ended on February 28, 1982, and deaths due to coronary heart disease (CHD), monitored through 1990. The nonfatal MIs occurred within 7 years of sample collection, whereas the majority of CHD deaths occurred more than 11 years after sample collection. Mean homocyst(e)ine concentrations were in the expected range and did not differ significantly between case patients and control subjects: MI cases, 12.6 μmol/L; MI controls, 13.1 μmol/L; CHD death cases, 12.8 μmol/L; and CHD controls, 12.7 μmol/L. Odds ratios versus quartile 1 for CHD deaths and MIs combined were as follows: quartile 2, 1.03; quartile 3, 0.84; and quartile 4, 0.92. Thus, in this prospective study, no association of homocyst(e)ine concentration with heart disease was detected. Homocyst(e)ine levels were weakly associated with the acute-phase protein (C-reactive protein). These results are discussed with respect to the suggestion that homocyst(e)ine is an independent risk factor for heart disease.