bluuebunny/crossref_metadata_2025 huggingface dataset:
Glycoprotein IIIa Pl
A
Polymorphism Associates With Progression of Coronary Artery Disease and With Myocardial Infarction in an Autopsy Series of Middle-Aged Men Who Died Suddenly
Authors: Mikkelsson Jussi , Perola Markus , Laippala Pekka , Savolainen Vesa , Pajarinen Jarkko , Lalu Kaisa , Penttilä Antti , Karhunen Pekka J.
Published: June 2011

Abstract
—Glycoprotein IIIa (GPIIIa) has a key role in the aggregation of thrombocytes, and it also mediates intimal hyperplasia after endothelial injuries; the possible association of the Pl
A1/A2
polymorphism of the gene for GPIIIa with coronary thrombosis and with the progression of coronary artery disease (CAD) is still to be confirmed. Therefore, the association of the Pl
A
polymorphism with the development of coronary atherosclerosis, coronary narrowing, and myocardial infarction (MI) was studied in a prospective, consecutive autopsy series of 300 middle-aged, white Finnish men (33 to 69 years) suffering sudden out-of-hospital or violent death. Coronary atherosclerosis was measured morphometrically and the coronary stenosis percentage determined from a cast rubber model of the coronary tree. We found a significant inverse relation (
P
=0.01) between the Pl
A2
-positive genotype and coronary artery stenosis. The frequency of possessing the Pl
A2
allele was significantly (odds ratio [OR] 0.45, 95% confidence interval [CI] 0.22 to 0.98) lower among men with >50% coronary stenosis (18.3%) than among those with <25% stenosis (32.9%). Although the Pl
A
polymorphism was not directly associated with MI, the Pl
A2
allele was present in 11 of the 22 men (50%) with MI and coronary thrombosis (OR 6.6, 95% CI 2.1 to 22.8) but in only 6 of the 47 (12.8%) with MI associated with severe stenosis in the absence of thrombosis. In line with this result, men possessing the Pl
A2
allele also had a larger area of fissured and ulcerated complicated lesions in their coronary arteries (
P
<0.05). The present results suggest that the Pl
A
polymorphism is involved in the development of CAD and MI. Men with the Pl
A2
allele may harbor more thin-walled, vulnerable coronary plaques, plaques prone to rupture, leading to massive, fatal thrombosis. In contrast, men homozygous for the Pl
A1
allele may more often show stable plaques and present with infarction caused by progressive coronary stenosis.
Potential Functional Significance of Brain-Type and Muscle-Type Nitric Oxide Synthase I Expressed in Adventitia and Media of Rat Aorta
Authors: Schwarz Petra M. , Kleinert Hartmut , Förstermann Ulrich
Published: June 2011

Abstract
—Skeletal muscle and myocardium express μNOS I, an elongated splice variant of neuronal-type nitric oxide (NO) synthase (NOS I), and NOS III, endothelial-type NO synthase, respectively. This study was designed to elucidate whether vascular smooth muscle also contains a constitutively expressed NO synthase isoform. In the rat, μNOS I contains an insert of 102 nucleotides after nucleotide 2865 of the cDNA, yielding a protein of 164 kd. Reverse transcription-polymerase chain reaction with primers flanking this insert and with insert-specific primers indicated that endothelium-denuded rat aorta expresses both brain-type NOS I and μNOS I. RNase protection analyses with an antisense RNA probe overlapping the μNOS I insert detected significant amounts of NOS I mRNA and lesser amounts of μNOS I mRNA in endothelium-denuded aorta. Western blots using a specific polyclonal antibody recognizing NOS I and μNOS I showed a major band of the 160-kd NOS I and a lesser band of a slightly larger protein in endothelium-denuded aorta. Immunohistochemistry demonstrated low levels of NOS I/μNOS I immunoreactivity in the medial layer of rat aorta, whereas the endothelium expressed only NOS III immunoreactivity. When the adventitia also was removed, NOS I and μNOS I mRNA decreased markedly but remained detectable in the medial layer. In functional experiments with endothelium-denuded rat aortic rings (that contained no NOS III), contractions induced by KCl were markedly increased in the presence of the NOS inhibitor
N
G
-nitro-
l
-arginine. These data demonstrate that 2 subforms of NOS I are expressed in nonendothelial components of rat aorta: NOS I and lesser amounts of μNOS I. Under certain conditions, this NOS I/μNOS I expression could serve as a backup system to the functionally predominant NOS III.
Evidence That Multiple Genes Influence Baseline Concentrations and Diet Response of Lp(a) in Baboons
Authors: Rainwater David L. , Kammerer Candace M. , VandeBerg John L.
Published: June 2011

Abstract
—We investigated the response of lipoprotein(a) [Lp(a)] levels to dietary fat and cholesterol in 633 baboons fed a series of 3 diets: a basal diet low in cholesterol and fat, a high-fat diet, and a diet high in fat and cholesterol. Measurement of serum concentrations in samples taken while the baboons were sequentially fed the 3 diets allowed us to analyze 3 Lp(a) variables: Lp(a)
Basal
, Lp(a)
RF
(response to increased dietary fat), and Lp(a)
RC
(response to increased dietary cholesterol in the high-fat environment). On average, Lp(a) concentrations significantly increased 6% and 28%, respectively, when dietary fat and cholesterol were increased (
P
<0.001). As expected, most of the variation in Lp(a)
Basal
was influenced by genes (
h
2
=0.881). However, less than half of the variation in Lp(a)
RC
was influenced by genes (
h
2
=0.347,
P
<0.0001), whereas the increase due to dietary fat alone was not significantly heritable (
h
2
=0.043,
P
=0.28). To determine whether Lp(a) phenotypic variation was due to variation in
LPA
, the locus encoding the apolipoprotein(a) [apo(a)] protein, we conducted linkage analyses by using
LPA
genotypes inferred from the apo(a) isoform phenotypes. All of the genetic variance in Lp(a)
Basal
concentration was linked to the
LPA
locus (log of the odds [LOD] score was 30.5). In contrast, linkage analyses revealed that genetic variance in Lp(a)
RC
was not linked to the
LPA
locus (LOD score was 0.036,
P
>0.5). To begin identifying the non-
LPA
genes that influence the Lp(a) response to dietary cholesterol, we tested, in bivariate quantitative genetic analyses, for correlation with low density lipoprotein cholesterol [LDLC; ie, non–high density lipoprotein cholesterol less the cholesterol contribution from Lp(a)]. LDLC
Basal
was weakly correlated with Lp(a)
Basal
(ρ
P
=0.018). However, LDLC
RC
and Lp(a)
RC
were strongly correlated (ρ
P
=0.382), and partitioning the correlations revealed significant genetic and environmental correlations (ρ
G
=0.587 and ρ
E
=0.251, respectively). The results suggest that increasing both dietary fat and dietary cholesterol caused significant increases in Lp(a) concentrations and that the response to dietary cholesterol was mediated by a gene or suite of genes that appears to exert pleiotropic effects on LDLC levels as well. The gene(s) influencing Lp(a) response to dietary cholesterol is not linked to the
LPA
locus.
Linkage of a Candidate Gene Locus to Familial Combined Hyperlipidemia
Authors: Aouizerat Bradley E. , Allayee Hooman , Cantor Rita M. , Dallinga-Thie Geesje M. , Lanning Christopher D. , de Bruin Tjerk W. A. , Lusis Aldons J. , Rotter Jerome I.
Published: June 2011

Abstract
—Familial combined hyperlipidemia (FCHL) is a common lipid disorder characterized by elevated levels of plasma cholesterol and triglycerides that is present in 10% to 20% of patients with premature coronary artery disease. To study the pathophysiological basis and genetics of FCHL, we previously reported recruitment of 18 large families. We now report linkage studies of 14 candidate genes selected for their potential involvement in the aspects of lipid and lipoprotein metabolism that are altered in FCHL. We used highly polymorphic markers linked to the candidate genes, and these markers were analyzed using several complementary, nonparametric statistical allele-sharing linkage methodologies. This current sample has been extended over the one in which we identified an association with the apolipoprotein (apo) AI-CIII-AIV gene cluster. We observed evidence for linkage of this region and FCHL (
P
<0.001), providing additional support for its involvement in FCHL. We also identified a new locus showing significant evidence of linkage to the disorder: the lecithin:cholesterol acyltransferase (LCAT) locus (
P
<0.0006) on chromosome 16. In addition, analysis of the manganese superoxide dismutase locus on chromosome 6 revealed a suggestive linkage result in this sample (
P
<0.006). Quantitative traits related to FCHL also provided some evidence of linkage to these regions. No evidence of linkage to the lipoprotein lipase gene, the microsomal triglyceride transfer protein gene, or several other genes involved in lipid metabolism was observed. The data suggest that the lecithin:cholesterol acyltransferase and apolipoprotein AI-CIII-AIV loci may act as modifying genes contributing to the expression of FCHL.
Carotid Intimal-Medial Thickness and Stiffness Are Not Affected by Hypercholesterolemia in Uncomplicated Essential Hypertension
Authors: Saba Pier Sergio , Roman Mary J. , Longhini Carlo , Scorzoni Daniela , Pini Riccardo , Devereux Richard B. , Ganau Antonello
Published: June 2011

Abstract
—The combined effects of hypertension and hypercholesterolemia on carotid anatomy and stiffness were studied in 62 normotensives, 141 uncomplicated essential hypertensives with a total cholesterol level <240 mg/dL, and 60 essential hypertensives with a total cholesterol level ≥240 mg/dL. Carotid ultrasonography was performed to evaluate intimal-medial thickness (IMT), relative wall thickness, and the presence of plaque. Carotid pressure waveforms were recorded by applanation tonometry to measure carotid stiffness (β) and pressure wave reflection (ie, augmentation index). After adjusting for age, body mass index, and smoking habit by analysis of covariance, no significant differences were found between normocholesterolemic hypertensives and hypercholesterolemic hypertensives in terms of IMT (0.79±0.19 versus 0.81±0.19 mm), relative wall thickness (0.27±0.07 versus 0.28±0.07), carotid stiffness (6.1±3.2 versus 5.6±2.7), augmentation index (18.7±12.9% versus 17.3±12.8%), and prevalence of plaque (30.8% versus 30.7%). In the whole population, carotid IMT was significantly related to age (
r
=0.43), systolic (
r
=0.35) and diastolic (
r
=0.35) blood pressures, body surface area (
r
=0.22), and cholesterol levels (
r
=0.22) (all
P
<0.05). Carotid stiffness was significantly related to age, blood pressure, body mass index, and body surface area but not to cholesterol levels. In multivariate analyses, age, body surface area, and systolic blood pressure, but not cholesterol, smoking habit, or sex, were independent correlates of IMT (multiple
R
=0.54,
P
<0.0001), whereas carotid stiffness was independently associated with age, body surface area, and sex (
R
=0.38,
P
<0.0001). In conclusion, hypertension is a potent stimulus of vascular hypertrophy. The superimposition of hypercholesterolemia does not substantially augment these changes or further increase arterial stiffness in uncomplicated hypertensive subjects.
β2-Glycoprotein I Promotes the Binding of Anionic Phospholipid Vesicles by Macrophages
Authors: Thiagarajan Perumal , Le Anhquyen , Benedict Claude R.
Published: June 2011

Abstract—β2-Glycoprotein I is a single-chain 50-kDa protein that circulates in plasma at a concentration of ≈200 μg/mL. Its physiological role remains uncertain, but an important clue is the frequent presence of antibodies to this protein in patients with recurrent thrombosis. We have isolated β2-glycoprotein I and examined its effect on the binding of phosphatidylserine (PS) vesicles by human monocyte–derived macrophages and by phorbol ester–stimulated THP-1 cells. β2-Glycoprotein I stimulated the binding of PS vesicles by these cells in a concentration-dependent manner. Vesicles containing other anionic phospholipids, such as cardiolipin, phosphatidic acid, or cardiolipin, inhibited the binding, whereas PC vesicles had no effect. Platelet-derived microvesicles, which contain anionic phospholipid on the outer leaflet of their phospholipid bilayer, also inhibited β2-glycoprotein I–dependent binding of anionic phospholipid vesicles. The binding is associated with incorporation of phospholipid in the cell membrane and internalization of β2-glycoprotein I. These findings suggest a physiological function for β2-glycoprotein I in the clearance of procoagulant anionic phospholipid-containing cell surfaces from the circulation.
Dissecting the Genetic Architecture of Lipids, Lipoproteins, and Apolipoproteins
Authors: Snieder Harold , van Doornen Lorenz J. P. , Boomsma Dorret I.
Published: June 2011

Abstract—We review the ways in which twin studies have been used to investigate the genetic architecture of lipids, lipoproteins, and apolipoproteins. We focus on the age dependency of genetic effects and the importance of pleiotropy for the lipid system. Finally, consequences are discussed of age dependency and pleiotropy for the design and power of twin studies aimed at detecting the actual quantitative trait loci (QTLs) involved. It is concluded that twin studies have played an important role and will remain highly valuable for the elucidation of the genetic architecture of lipids, lipoproteins, and apolipoproteins. Twins can efficiently be used to identify the location and function of QTLs. Taking account of pleiotropy and age-dependent gene expression in study design and data analysis will improve the power and efficiency to find these QTLs for components of the lipid system.
Evidence That Acute Insulin Administration Enhances LDL Cholesterol Susceptibility to Oxidation in Healthy Humans
Authors: Quiñones-Galvan Alfredo , Sironi Anna Maria , Baldi Simona , Galetta Fabio , Garbin Ulisse , Fratta-Pasini Anna , Cominacini Luciano , Ferrannini Ele
Published: June 2011

Abstract
—Increased free radical production and hyperinsulinemia are thought to play a role in experimental and human atherosclerosis, but the relation between the 2 abnormalities has not been studied. In 23 healthy volunteers, we measured the susceptibility of circulating low-density lipoprotein (LDL) cholesterol particles to in vitro copper sulfate oxidation (measured as the lag phase) and cell-mediated oxidative modification (measured as malondialdehyde generation in LDL during incubation with human umbilical vein endothelial cells), as well as the vitamin E content of LDL cholesterol at baseline and after 2 hours of physiological hyperinsulinemia (euglycemic insulin clamp). The lag time of LDL oxidation decreased from control values of 108±3 and 107±3 minutes (at baseline and after 2 hours of saline infusion) to 101±3 minutes after 2 hours of clamping (
P
<0.0001). At corresponding times, cell-mediated malondialdehyde generation in LDL rose from 4.96±0.11 and 4.98±0.10 to 5.28±0.10 nmol/L (
P
=0.0006), whereas the LDL vitamin E content decreased from 6.78±0.06 and 6.77±0.06 to 6.64±0.06 μg/mg (
P
<0.04). The insulin-induced shortening of the lag phase was directly related to the decrement of vitamin E in LDL; furthermore, in subjects with higher baseline serum triglyceride levels, insulin induced a greater shortening of the lag phase than in subjects with low baseline triglycerides. We conclude that in healthy humans acute physiological hyperinsulinemia enhances the oxidative susceptibility of LDL cholesterol particles. This effect may have pathogenic significance for atherogenesis in insulin resistant states.
Hyperlipidemia of ApoE2(Arg
158
-Cys) and ApoE3-Leiden Transgenic Mice Is Modulated Predominantly by LDL Receptor Expression
Authors: van Dijk Ko Willems , van Vlijmen Bart J.M. , de Winther Menno P.J. , van ’t Hof Belinda , van der Zee Andre , van der Boom Hans , Havekes Louis M. , Hofker Marten H.
Published: June 2011

Abstract
—To investigate the relative roles of the LDL receptor– and non–LDL receptor–mediated pathways in the clearance of apolipoprotein E (apoE) variants in vivo, we have generated apoE2(Arg
158
-Cys) (apoE2) and apoE3-Leiden transgenic mice deficient for the endogenous mouse
Apoe
and
Ldl receptor
genes (
Apoe−/−.Ldlr−/−
mice). Unexpectedly, on the
Apoe−/−.Ldlr−/−
background, expression of neither apoE2 nor apoE3-Leiden results in a decrease of the hyperlipidemia. In contrast, serum cholesterol levels are increased by the introduction of apoE2 and apoE3-Leiden in
Apoe−/−.Ldlr−/−
mice (to 39.1±7.1 and 37.6±7.6 mmol/L, respectively, from 25.9±6.5 mmol/L). In addition, in these transgenic mice, the serum triglyceride levels are substantially increased (to 9.6±7.0 and 5.8±2.8 mmol/L, respectively, from 0.7±0.5 mmol/L), which is associated with a decreased efficiency of in vitro LPL-mediated lipolysis of circulating VLDL. The VLDL-triglyceride secretion rate is not affected by the expression of apoE2 or apoE3-Leiden on the
Apoe−/−.Ldlr−/−
background. These results indicate that in the absence of the LDL receptor, clearance of triglyceride-rich apoE2 and apoE3-Leiden–containing lipoproteins via alternative hepatic receptors, such as the LDL receptor–related protein (LRP) is inefficient. Although apoE2 and apoE3-Leiden are disturbed in binding to the LDL receptor in vitro, expression of 1 or 2 mouse
Ldlr
alleles in an apoE2.
Apoe−/−
or apoE3-Leiden.
Apoe−/−
background results in a gene dose–dependent decrease of the hyperlipidemia. Furthermore, overexpression of the LDL receptor via adenovirus-mediated gene transfer rescues the hyperlipidemia associated with apoE2 and apoE3-Leiden expression. These data indicate that in apoE2 and apoE3-Leiden transgenic mice, the LDL receptor constitutes the predominant route for clearance of VLDL remnants, carrying even poorly binding apoE variants, and that this pathway is functional despite an apoE-mediated disturbance in VLDL triglyceride lipolysis.
Estrogen Increases Apolipoprotein (Apo) A-I Secretion in Hep G2 Cells by Modulating Transcription of the Apo A-I Gene Promoter
Authors: Lamon-Fava Stefania , Ordovas Jose M. , Schaefer Ernst J.
Published: June 2011

Abstract
—Estrogen administration to postmenopausal women has been shown to increase plasma levels of apolipoprotein (apo) A-I. A human hepatoma cell line, Hep G2, was used to test the hypothesis that estrogen increases the hepatic production of apo A-I by modulating gene expression. When Hep G2 cells were treated for 24 hours with E
2
, the apo A-I content in the medium increased 4.3±1.0-fold at 10 μmol/L E
2
and 1.8±0.4-fold at 1 μmol/L E
2
compared with untreated cells. A time-course experiment indicated that there was no E
2
-dependent (10 μmol/L) increase in apo A-I medium content at 1 hour and 2 hours and that apo A-I was 165% of controls at 6 hours and 440% at 24 hours. Hep G2 cells were transfected, by the cationic lipid method, with constructs containing serial deletions of the 5′ region of the apo A-I gene (−41/+397, −256/+397, and −2500/+397) cloned in front of the luciferase gene and with or without a 7-kb region spanning the apo C-III/A-IV intergenic region, which has been shown to contain regulatory elements for the expression of the apo A-I gene. With the exception of the construct containing only the basal promoter (−41/+397), the expression of all constructs was 2- to 3-fold greater in the presence of E
2
. The smallest construct that maintained E
2
responsiveness, the −256/+397 construct, does not contain a typical estrogen-responsive element. In the same transfection experiments, the 4-fold increase in apo A-I in the culture medium was preserved. However, when the same set of transfections was performed by the calcium phosphate precipitation method, the E
2
effect on the apo A-I content in the culture medium and on transcription activation was nearly abolished. This effect was probably mediated by Ca
2+
, because incubation of cells with 20 mmol/L CaCl
2
abolished the E
2
response. In conclusion, E
2
increases apo A-I production in hepatic cells by increasing the transcription of the apo A-I gene.
Glucose Phosphorylation Is Essential for the Turnover of Neutral Lipid and the Second Stage Assembly of Triacylglycerol-Rich ApoB-Containing Lipoproteins in Primary Hepatocyte Cultures
Authors: Brown Anna-Marie , Wiggins David , Gibbons Geoffrey F.
Published: June 2011

Abstract
—Primary hepatocytes cultured in a medium supplemented with amino acids and lipogenic substrates responded to increased extracellular glucose by increasing the secretion of VLDL apoB. This effect was accompanied by an increased secretion of VLDL triacylglycerol (TAG) derived from endogenous stores. Glucose also stimulated intracellular TAG mobilization via the TAG lipolysis/esterification cycle. All these effects were abolished in the presence of mannoheptulose (MH), an inhibitor of glucose phosphorylation. Glucose also gave rise to a modest (50% to 60%) increase in the incorporation of
35
S methionine into newly synthesized apoB (
P
<0.05) and to a doubling of newly-synthesized apoB secretion as VLDL (
P
<0.05). The magnitude of these effects was similar for apoB-48 and for apoB-100. MH inhibited apoB-48 and apoB-100 synthesis and VLDL secretion at all glucose concentrations. The effects of glucose and MH on the secretion of newly-synthesized apoB-48 or apoB-100 as small dense particles were less pronounced. Glucose had no effects on the posttranslational degradation of newly-synthesized apoB-100 or apoB-48. However, this process was significantly enhanced by MH. The results suggest that glucose stimulates TAG synthesis, turnover, and output as VLDL. These effects are associated with an increased VLDL output of apoB mediated mainly by an increase in the net synthesis of both apoB-48 and apoB-100. All these changes are prevented by interference with glucose phosphorylation. Output of small, dense, apoB-containing particles is relatively unaffected by the glucose and MH-induced changes in TAG synthesis and lipolysis, an observation which suggests that only the bulk lipid addition step of VLDL assembly is affected by changes in glucose metabolism.
Serum Paraoxonase After Myocardial Infarction
Authors: Ayub Aamir , Mackness Michael I. , Arrol Sharon , Mackness Bharti , Patel Jeetesh , Durrington Paul N.
Published: June 2011

Abstract
—HDL has been shown to prevent the oxidative modification of LDL. The antioxidant activity of HDL is believed to reside in its enzymes, particularly paraoxonase. Human serum paraoxonase (PON1) is closely associated with a specific HDL subfraction also containing apoA1 and clusterin. Recently PON1 has been implicated in the pathogenesis of atherosclerosis. We have examined the activity, concentration, and specific activity of PON1 in 50 patients on admission to hospital immediately after acute myocardial infarction (MI) and in 48 age- and gender-matched controls. Serum PON1 activity and concentration were significantly lower in patients with MI than in controls (activity, 221.5 [99.3 to 303.2] nmol · min
−1
· mL
−1
in controls and 130.1 [78.9 to 230.3] nmol · min
−1
· mL
−1
in MI patients [
P
<0.05]; concentration, 95.7 [73.2 to 135.5] μg/mL in controls and 35.4 [21.6 to 51.3] μg/mL in MI patients [
P
<0.001]). PON1-specific activity was significantly higher in patients with MI than in controls (1.5 [0.9 to 2.9] versus 3.4 [2.0 to 8.5] nmol · min
−1
· μg
−1
[
P
<0.001]) due to the much lower PON1 concentration. PON1 activity had risen significantly (
P
<0.05) to 158.1 (85.4 to 282.0) nmol · min
−1
· mL
−1
at day 42 but was still significantly less than that of controls. No significant variation in PON1 concentration occured in the days after MI or at 6 weeks. Also, no significant variation in specific activity was seen after MI. When the patients were divided into subgroups based on whether or not they received thrombolytic therapy on admission to hospital, no significant difference in PON1 levels was observed. Serum HDL cholesterol in patients with MI on admission was not significantly different than in controls, and the decrease that occurred by the fifth day after MI did not explain the lower PON1 levels. We conclude that low serum PON1 activity in patients with MI may be a consequence of the coronary event itself or could have been present before MI. The low PON1 activity was also not explicable on the basis of PON1 genotypes because the prevalence of genotypes associated with low activity was not sufficient to explain fully the difference in activity levels between patients and controls. The explanation for the low PON1 activity was most likely a decrease in serum PON1 concentration. The importance of PON1 as a predictive risk factor for MI should be assessed in future studies.
Phenotype and Genotype Expression in Pseudohomozygous Factor V
LEIDEN
Authors: Kalafatis Michael , Bernardi Francesco , Simioni Paolo , Lunghi Barbara , Girolami Antonio , Mann Kenneth G.
Published: June 2011

Abstract
—The presence of a DNA mutation is frequently used to define a disease or a risk state. Because DNA typing has become easy and convenient in contrast to protein characterization, it is generally assumed that a mutation if present (or not) at the DNA level will be also present (or not) in the corresponding protein. However, discrepancies between phenotype and genotype can occur. A point mutation in the coagulation factor V gene (G
1691
→A, resulting in an Arg
506
→Gln amino acid substitution in the factor V molecule [factor V
LEIDEN
], leading to activated protein C resistance) is the most common genetic risk factor for familial thrombophilia. A pseudohomozygous factor V
LEIDEN
phenotype would occur if a heterozygous individual for factor V
LEIDEN
also did not express the “normal” (non-Leiden) factor V allele. However, to date, no data have been available to confirm the presence of only the factor V
LEIDEN
form in the plasma of these individuals. Platelet mRNA from 2 presumed pseudohomozygous patients and their family members was isolated, the amplified partial cDNAs were sequenced or restricted, and the allelic bands were quantified. Both patients were found to be heterozygous for the G
1691
→A substitution at both the DNA and mRNA levels. The presence of either the normal or mutated form of factor V in the patients’ plasmas was investigated using a monoclonal antibody to factor V that recognizes an epitope located between residues 307 and 506 of the factor Va heavy chain. No normal factor V could be detected in the plasmas of the 2 propositi. The present data demonstrate absence of a correlation between genotype at position 1691 (at the DNA and mRNA levels) and the corresponding phenotype data found in the plasmas of patients with pseudohomozygous factor V
LEIDEN
. Overall, these data suggest the existence of heterogeneous genetic “lesions,” which interfere with factor V expression, processing, secretion, and/or stability. Because the presence of the factor V
LEIDEN
molecule in plasma is directly related to pathology, identification and quantification of the circulating forms of factor V in plasma may be required for the diagnosis of individuals with activated protein C resistance.
Glycoprotein IIb/IIIa Antagonist FK633 Could Not Prevent Neointimal Thickening in Stent Implantation Model of Canine Coronary Artery
Authors: Ueda Yasunori , Kitakaze Masafumi , Imakita Masami , Ishibashi-Ueda Hatsue , Minamino Tetsuo , Asanuma Hiroshi , Ozaki Tohru , Imamura Emiko , Kuzuya Tsunehiko , Hori Masatsugu
Published: June 2011

Abstract
—The platelet glycoprotein (GP) IIb/IIIa receptor antagonist appears to reduce the need for revascularization after coronary angioplasty. However, since the effect of GP IIb/IIIa receptor antagonist on the in-stent neointimal thickening has not been clarified, we examined it in the canine model. The beagle dogs were assigned to the control (n=7) or the GP IIb/IIIa receptor antagonist FK633 group (n=7). FK633 was administered by subcutaneous osmotic pumps (0.2 mg · kg
−1
· h
−1
) and an intravenous bolus injection (1 mg/kg) before stenting. A coil stent was implanted in the left circumflex coronary arteries. The platelet aggregation capability was significantly (<5%) and consistently reduced by FK633 except for the mild elevation (10% to 30%) on the next day of stenting. Hearts were excised 3 months after stent implantation. The area of intima and media and the area stenosis were obtained from the sections of the stented arteries. The area of intima and media and the area stenosis (1.3±0.2 mm
2
, 41.8±7.5% and 1.3±0.2 mm
2
, 33.9±6.7% in the FK633 and the control group, respectively) were not different between the groups. We conclude that, although GP IIb/IIIa antagonist FK633 prevented the platelet aggregation significantly and consistently, it could not prevent the neointimal thickening after stent implantation in canine coronary artery.
Inhibition of Arterial Thrombus Formation by ApoA1 Milano
Authors: Li Dayuan , Weng Sharon , Yang Baichun , Zander Dani S. , Saldeen Tom , Nichols Wilmer W. , Khan Saeed , Mehta Jawahar L.
Published: June 2011

Abstract
—The mutant form of human apoA1, known as apoA1 Milano, is formed as a result of arginine 173 to cysteine substitution and inhibits experimental atherosclerosis in cholesterol-fed animals. This study was designed to determine if apoA1 Milano would modify arterial thrombogenesis. Sprague Dawley rats were intravenously administered the carrier alone (n=8) or apoA1 Milano (20 mg · kg
−1
· d
−1
for 4 to 10 days, n=17). The abdominal cavity was opened, and the abdominal aorta was isolated. Whatman paper impregnated with 35% FeCl
3
was wrapped around the surface of the aorta, and aortic flow was recorded continuously. In carrier-treated rats, an occlusive platelet-fibrin-rich thrombus was formed in 21.2±4.1 (mean±SD) minutes. Treatment of rats with apoA1 Milano markedly delayed time to thrombus formation (38.8±11.9 versus 21.2±4.1 minutes,
P
<0.01), inhibited platelet aggregation (25±7% versus 50±11%,
P
<0.01), and reduced weight of the thrombus (18.5±1.8 versus 23.7±2.3 mg/cm,
P
<0.01). Total cholesterol and HDL levels remained similar in both groups of rats, but plasma apoA1 Milano levels were elevated in apoA1 Milano–treated rats. In in vitro studies, incubation of platelets with apoA1 Milano reduced ADP-induced platelet aggregation by about 50%, but apoA1 Milano had no direct effect on vasoreactivity. This study provides further evidence for critical role of platelets in thrombosis. Use of apoA1 Milano offers a novel approach to inhibit arterial thrombosis.
Analysis of LDL Receptor Gene Mutations in Italian Patients With Homozygous Familial Hypercholesterolemia
Authors: Bertolini S. , Cassanelli S. , Garuti R. , Ghisellini M. , Simone M. L. , Rolleri M. , Masturzo P. , Calandra S.
Published: June 2011

Abstract—The aim of this study was the characterization of mutations of the LDL receptor gene in 39 Italian patients with homozygous familial hypercholesterolemia, who were examined during the period 1994 to 1996. The age of the patients ranged from 1 to 64 years; one third of them were older than 30. Plasma LDL cholesterol level ranged from 10.8 to 25.1 mmol/L. The residual LDL receptor activity, measured in cultured fibroblasts of 32 patients, varied from <2% to 30% of normal and was inversely correlated with the plasma LDL cholesterol level (r=−0.665;P<0.003). The most severe coronary atherosclerosis was observed in those patients with the lowest residual LDL receptor activity (≤5% of normal) and the highest plasma LDL cholesterol levels. Twenty-nine patients (23 of whom were unrelated) were found to be homozygotes at the LDL receptor locus. In this group we discovered 2 major rearrangements and 12 different point mutations (9 in the coding region and 3 in splice sites). Some mutations (D200G, C358R, V502M, G528D, and P664L) were found in 3 or more unrelated patients. Patients with the same mutation shared the same haplotype at the LDL receptor gene locus and came from the same geographic area. Ten patients (9 of whom were unrelated) were found to be compound heterozygotes. The mutations found in this group consisted of one large deletion and 12 point mutations (11 in the coding sequence and one in a splice site). In 3 compound heterozygotes we failed to identify the second mutant allele at the LDL receptor locus. These observations confirm the allelic heterogeneity underlying familial hypercholesterolemia in the Italian population and indicate that the variability of phenotypic expression of homozygous familial hypercholesterolemia is, to a large extent, related to the type of mutation of the LDL receptor gene.
The Relationship Between Risk Factor Levels and Presence of Coronary Artery Calcification is Dependent on
Apolipoprotein E
Genotype
Authors: Kardia S. L. R. , Haviland M. B. , Ferrell R. E. , Sing C. F.
Published: June 2011

Abstract
—An important research question in the study of the genetics of coronary artery disease (CAD) is whether information about genetic variation will improve our ability to predict CAD beyond established risk factors. This question is especially relevant to the goal of identifying young, asymptomatic adults with coronary atherosclerosis who would benefit most from interventions to reduce risk. Coronary artery calcification (CAC) detected by electron-beam computed tomography is a relatively new method for detecting coronary atherosclerosis in asymptomatic individuals that has been shown to be a more accurate indicator of coronary atherosclerosis in asymptomatic individuals than other noninvasive techniques. In a study of asymptomatic women (n=169) and men (n=160) between the ages of 20 and 59 representative of the Rochester, Minnesota population, we used logistic regression to ask whether the most common
Apolipoprotein (Apo) E
genotypes (ε
3/2
, ε
3/3
, and ε
4/3
) predict the presence of CAC. The addition of information about
ApoE
genotypes to logistic models containing each separate risk factor did not improve prediction of CAC (
P
>0.10 in both women and men). However, there was significant evidence (
P
<0.10) that associations between variation in the probability of having CAC and variation in body mass index, plasma total cholesterol, and plasma ApoB in men and body mass index, plasma triglycerides, plasma ApoA1, and plasma ApoE in women were dependent on
ApoE
genotype. Thus, variation in the gene coding for ApoE may play a role in determining the contribution of established risk factors to risk of CAC.
Large-Artery Elastic Properties in Young Men
Authors: Toikka Jyri O. , Niemi Pekka , Ahotupa Markku , Niinikoski Harri , Viikari Jorma S. A. , Rönnemaa Tapani , Hartiala Jaakko J. , Raitakari Olli T.
Published: June 2011

Abstract—Measures of arterial elasticity have been proposed as surrogate markers for asymptomatic atherosclerosis. We investigated the relations of serum lipoproteins, oxidized low-density lipoprotein (ox-LDL), and familial hypercholesterolemia (FH) to arterial elasticity among young men. As a marker of arterial elasticity we measured compliance in the thoracic aorta by using magnetic resonance imaging and in the common carotid artery by using ultrasound. LDL diene conjugation was used as a marker of ox-LDL. In study I, 25 healthy men (aged 29 to 39) were classified into 2 extreme groups according to previously measured high-density lipoprotein cholesterol to total cholesterol ratio (HDL-C/TC ratio). In study II, the healthy men were used as controls for 10 age matched asymptomatic patients with FH. In healthy men, the group with low HDL-C/TC ratio had decreased carotid artery compliance (2.3±0.4% versus 1.9±0.5%/10 mm Hg,P=0.034). In univariate analysis, the compliance of the carotid artery associated with ox-LDL (r=−0.49,P=0.016) and HDL-C/TC ratio (r=0.41,P=0.040). In multivariate regression analyses, ox-LDL was the only independent determinant for compliance of the carotid artery (P=0.016). Aortic elasticity was not related to standard lipid variables, but the compliance of the ascending aorta associated with ox-LDL (r=−0.44,P=0.030). In FH patients, arterial elasticity was similar to that in controls. We conclude that elasticity of the common carotid artery is affected by serum lipid profile in young men. The current study demonstrates for the first time an in vivo association between ox-LDL and arterial elasticity suggesting that oxidative modification of LDL may play a role in the alteration of arterial wall elastic properties.
Gene Polymorphism of t-PA is Associated With Forearm Vascular Release Rate of t-PA
Authors: Jern Christina , Ladenvall Per , Wall Ulrika , Jern Sverker
Published: June 2011

Abstract
—We have observed marked interindividual differences in release rates of tissue-type plasminogen activator (t-PA) among healthy subjects. The objective of the current study was to test the hypothesis that there is an association between a genetic variation at the t-PA locus and the in vivo release rate of t-PA. Fifty-one healthy males were studied at rest in the morning and 27 of these were also subjected to a mental stress test. Net release rates of total t-PA across the forearm vascular bed were calculated as the product of the venoarterial concentration gradient and forearm plasma flow. Zygosity for an Alu-repeat polymorphism in intron 8 of the t-PA gene was determined by a polymerase chain reaction. Basal t-PA release rates differed markedly by genotype (ANOVA,
P
<0.05); subjects homozygous for the insertion had a significantly higher release rate (mean 10.9 ng · min
−1
· L
−1
, n=19) than both heterozygotes (4.5 ng · min
−1
· L
−1
, n=26) and subjects homozygous for the deletion (0.9 ng · min
−1
· L
−1
, n=6). After 2 minutes of mental stress release rates had increased approximately 2-fold in all groups. Arterial and venous plasma levels of t-PA were unrelated to genotype. In conclusion, the current results provide the first evidence of an association between a common genetic variation at the t-PA locus and interindividual differences in net release rates of t-PA in vivo. The relationship is not reflected by circulating steady-state plasma levels and can thus not be disclosed by conventional venous plasma sampling.
Cooperation Between VEGF and TNF-α Is Necessary for Exposure of Active Tissue Factor on the Surface of Human Endothelial Cells
Authors: Camera Marina , Giesen Peter L. A. , Fallon Jay , Aufiero Barbara M. , Taubman Mark , Tremoli Elena , Nemerson Yale
Published: June 2011

Abstract
—This study was undertaken to characterize tissue factor (TF) induction, localization, and functional activity in cultured human umbilical vein endothelial cells (HUVECs) exposed to recombinant vascular endothelial growth factor (rVEGF) and recombinant tumor necrosis factor-α (rTNF-α). rVEGF (1 nmol/L) and rTNF-α (500 U/mL) synergistically increased TF mRNA, protein, and total activity, as measured in cell lysates. To examine surface TF expression, living cells were treated with antibody to TF and examined microscopically. Almost no staining was seen in control cells or cells treated with a single agent. In contrast, cells treated with both agonists showed intense membrane staining with surface patches, appearing as buds by confocal microscopy. To determine surface TF activity, studies were performed using a parallel-plate flow chamber, which allows detection of factor Xa generation on living cells. rVEGF and rTNF-α induced little surface TF activity (0.032±0.008 and 0.014±0.008 fmol/cm
2
, respectively). In combination, they significantly increased TF expression on the cell surface (0.429±0.094 fmol/cm
2
,
P
<0.05). These data indicate that the synergistic effect of rVEGF and rTNF-α is necessary to generate functional TF on the surface of endothelial cells. The requirement for multiple agonists to expose active TF may serve to protect endothelial cells from acting as a procoagulant surface, even under conditions of cell perturbation.
Identification of Megalin/gp330 as a Receptor for Lipoprotein(a) In Vitro
Authors: Niemeier Andreas , Willnow Thomas , Dieplinger Hans , Jacobsen Christian , Meyer Nicolette , Hilpert Jan , Beisiegel Ulrike
Published: June 2011

Abstract
—Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein of unknown physiological function. The mechanism of Lp(a) atherogenicity as well as its catabolic pathways are only incompletely understood at present. In this report, we show that the low density lipoprotein receptor (LDLR) gene family member megalin/glycoprotein (gp) 330 is capable of binding and mediating the cellular uptake and degradation of Lp(a) in vitro. A mouse embryonic yolk sac cell line with native expression of megalin/gp330 but genetically deficient in LDLR-related protein (LRP) and a control cell line carrying a double knockout for both LRP and megalin/gp330 were compared with regard to their ability to bind, internalize, and degrade dioctadecyltetramethylindocarbocyanine perchlorate (DiI)-fluorescence–labeled Lp(a) as well as equimolar amounts of
125
I-labeled Lp(a) and LDL. Uptake and degradation of radiolabeled Lp(a) by the megalin/gp330-expressing cells were, on average, 2-fold higher than that of control cells. This difference could be completely abolished by addition of the receptor-associated protein, an inhibitor of ligand binding to megalin/gp330. Mutual suppression of the uptake of
125
I-Lp(a) and of
125
I-LDL by both unlabeled Lp(a) and LDL suggested that Lp(a) uptake is mediated at least partially by apolipoprotein B100. Binding and uptake of DiI-Lp(a) resulted in strong signals on megalin/gp330-expressing cells versus background only on control cells. In addition, we show that purified megalin/gp330, immobilized on a sensor chip, directly binds Lp(a) in a Ca
2+
-dependent manner with an affinity similar to that for LDL. We conclude that megalin/gp330 binds Lp(a) in vitro and is capable of mediating its cellular uptake and degradation.
Irradiation Induces Upregulation of CD31 in Human Endothelial Cells
Authors: Quarmby Steven , Kumar Pat , Wang JiMin , Macro Janet A. , Hutchinson Jerry J. , Hunter Robin D. , Kumar Shant
Published: June 2011

Abstract—Radiation-induced vascular injury is believed to be a major factor contributing to parenchymal atrophy, fibrosis and necrosis in normal tissue after radiotherapy. In this study irradiation of human umbilical vein endothelial cells (HUVECs) significantly increased adherence of U-937 cells in a time-dependent manner. Given the potential multifunctional role of CD31 in the vasculature we have examined the possible effects of irradiation on levels of CD31 expression in HUVECs. Irradiation upregulated CD31 expression on HUVECs, independently of initial plating density and radiation-induced changes such as cell number, cell cycle stage, or cell size. CD31 mRNA levels were raised in irradiated HUVECs relative to controls. Both CD31 mRNA and surface protein showed similar changes, suggesting that the increase in mRNA in irradiated HUVECs is responsible for the elevation in cell surface protein. A semi-quantitative study of tissue specimens from patients who had received radiotherapy indicated that CD31 staining in the blood vessels from irradiated tissues was increased compared with controls. Endothelial CD31 is important in the transmigration of leukocytes. We have demonstrated that the incorporation of monoclonal antibody to CD31 significantly inhibited the transmigration of human peripheral blood leukocytes through a monolayer of irradiated HUVECs. Taken together these data strongly suggest that irradiation induces a marked increase in CD31 expression on endothelial cells as part of a general response to irradiation. Its upregulation may play an important role in the development of radiation-induced normal tissue damage and thus is a possible target for therapeutic intervention.
Low-Density Lipoprotein Particle Size Is Inversely Related to Plasminogen Activator Inhibitor-1 Levels
Authors: Festa Andreas , D’Agostino Ralph , Mykkänen Leena , Tracy Russell , Howard Barbara V. , Haffner Steven M.
Published: June 2011

Abstract
—High levels of plasminogen activator inhibitor-1 (PAI-1) and preponderance of small dense low-density lipoproteins (LDL) have both been associated with atherosclerotic disease and with the insulin resistance syndrome (IRS). In vitro studies have shown a stimulatory effect of various lipoproteins on PAI-1 release from different cells, including endothelial cells and adipocytes. The authors sought to investigate the relation of PAI-1 to LDL particle size in a large tri-ethnic population (n=1549) across different states of glucose tolerance. LDL size was determined by gradient gel electrophoresis, and PAI-1 was measured by a 2-site immunoassay, sensitive to free PAI-1. PAI-1 was inversely related to LDL size in the overall population (r=−0.21,
P
<0.0001), independent of gender and ethnicity. However, the authors found a significant interaction with glucose tolerance status (
P
=0.035). In univariate analysis, the association between PAI-1 and LDL size was most pronounced in subjects with normal glucose tolerance (NGT, r=−0.22,
P
<0.0001) and weaker in impaired glucose tolerance (IGT, r=−0.12,
P
=0.03) and type-2 diabetes (r=−0.10,
P
=0.02). After adjustment for demographic variables and metabolic variables known to influence PAI-1 levels (triglyceride and insulin sensitivity), a significant inverse relation of LDL size to PAI-1 levels was only present in NGT (
P
=0.023). In subjects with IGT or overt diabetes, who usually have elevated PAI-1 levels, additional factors other than LDL size seem to contribute more importantly to PAI-1 levels. The demonstrated inverse relation of LDL size and PAI-1 levels provides one possible explanation for the atherogeneity of small dense LDL particles.
Extent and Composition of Coronary Lesions in Relation to Fat Distribution in Women Younger Than 50 Years of Age
Authors: Kortelainen Marja-Leena , Särkioja Terttu
Published: June 2011

Abstract—To ascertain the relationship between the extent and composition of coronary arterial lesions and the regional distribution of fat in healthy women younger than 50 years of age, a series of 30 forensic autopsy cases were investigated. Body height and weight, waist and hip circumferences, and the thickness of the subscapular and abdominal subcutaneous fat were measured; the body mass index (BMI) and waist-to-hip ratio (WHR) were calculated, and omental and mesenteric fat deposits were weighed. The extent of coronary lesions was measured by planimetry, and the thickness of the intima-media was measured by computerized image analysis. Intimal macrophage foam cells and smooth muscle cells were detected by immunohistochemistry, and macrophages were quantified. The intima media thickness in the left anterior descending artery, circumflex artery, and right coronary artery varied significantly across the tertiles of WHR when age and BMI were adjusted, being highest when WHR exceeded 0.87. The thickest lesions also contained the largest numbers of macrophage foam cells. The intima-media thicknesses were highest with increased amounts of intraperitoneal fat. These results indicate that the severity of clinically silent coronary lesions in younger female individuals is associated with increased WHR and increased amounts of intraperitoneal fat. These results emphasize the importance of WHR as a coronary risk indicator in younger women.