bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipoprotein(a) Assembly
Authors: Gabel Brent R. , May Lorraine F. , Marcovina Santica M. , Koschinsky Marlys L.
Published: June 2011

We have developed a system for the quantitative assessment of the efficiency of lipoprotein(a) [Lp(a)] formation in vitro. Amino-terminally truncated derivatives of a 17-kringle form of recombinant apo(a) [r-apo(a)] were transiently expressed in human embryonic kidney cells. Equimolar amounts of r-apo(a) derivatives were incubated with a fourfold molar excess of purified human low density lipoprotein, and r-Lp(a) formation was assessed by densitometric analysis of Western blots. Although r-Lp(a) formation was observed with each r-apo(a) derivative, both the rate and extent of particle formation were greatly lower on removal of kringle IV type 7. Additional substantial decreases in these parameters were observed on removal of kringle IV type 8, thereby suggesting a major role for these two kringles in Lp(a) assembly. We directly demonstrated that the lysine-binding sites (LBSs) within kringle IV types 5-9 are “masked” in the context of the Lp(a) particle and are consequently unavailable for interaction with lysine-Sepharose. Using site-directed mutagenesis, we also demonstrated that the previously described LBS in kringle IV type 10 is not required for r-Lp(a) formation: r-Lp(a) formation using a mutated form of apo(a) that lacks this LBS is comparable in efficiency to that of wild-type r-apo(a) and can be inhibited to a similar extent by ε-amino-
n
-caproic acid. In summary, the results of our study indicate that apo(a) kringle IV types 7 and 8 are required for maximal efficiency of Lp(a) formation, likely by virtue of their ability to mediate lysine-dependent noncovalent interactions with apoB-100 that precede disulfide bond formation.
Visceral Fat Accumulation and Its Relation to Plasma Hemostatic Factors in Healthy Men
Authors: Cigolini M. , Targher G. , Andreis I.A. Bergamo , Tonoli M. , Agostino G. , De Sandre G.
Published: June 2011

Abstract
The associations between abdominal visceral fat and the plasma hemostatic system were examined in 38-year-old healthy men (n=52) with a wide range of fatness and fat distribution. Plasma hemostatic factors and metabolic parameters, including glucose tolerance, were measured, and body fatness and adipose tissue distribution were assessed by using computed tomography. The men with more visceral fat (ie, higher than the median value [n=26]) had a less favorable metabolic profile than the men with less visceral fat (n=26). They also had significantly (
P
<.05) higher plasma fibrinogen, factor VIII clotting activity, tissue-type plasminogen activator antigen, and plasminogen activator inhibitor–1 (PAI-1) activity (19.2±2.4 versus 8.5±1.6 AU/mL,
P
<.001) and lower basal tissue-type plasminogen activator activity. After adjustment for plasma insulin, the men with larger abdominal visceral fat area still had significantly higher plasma PAI-1 activity, but no difference was found in any of the other hemostatic factors. In multiple linear regression analysis, abdominal visceral fat area was a positive predictor of plasma PAI-1 activity, but it failed to show any significant association with other hemostatic factors after controlling for plasma insulin. These results suggest the presence of relationships between abdominal visceral fat and several plasma hemostatic factors that are largely mediated by concomitant alterations in plasma insulin concentration. In addition, our results suggest that abdominal accumulation of visceral fat is an independent predictor of plasma PAI-1 activity.
Lysophosphatidylcholine Potentiates the Mitogenic Activity of Modified LDL for Human Monocyte–Derived Macrophages
Authors: Sakai Masakazu , Miyazaki Akira , Hakamata Hideki , Sato Yoshihiro , Matsumura Takeshi , Kobori Shozo , Shichiri Motoaki , Horiuchi Seikoh
Published: June 2011

Abstract
The growth of murine peritoneal macrophages is induced by oxidized LDL (Ox-LDL), and lysophosphatidylcholine (lysoPC) plays an important role in its mitogenic activity. In the present study, Ox-LDL–induced macrophage growth was examined with human monocyte–derived macrophages. The cell growth of human macrophages was significantly induced by Ox-LDL but not by acetylated LDL (acetyl-LDL). The treatment of acetyl-LDL with phospholipase A
2
, however, led to a marked increase in its mitogenic activity, with a concomitant conversion of 75% of its phospholipids to lysoPC. The growth-stimulating activity became positive only when both acetyl-LDL and lysoPC were coincubated, although neither of them exhibited cell growth–promoting activity. These results suggest that Ox-LDL could stimulate the growth of human monocyte–derived macrophages, and lysoPC may play an essential role in the mitogenic activity of Ox-LDL.
Decreased Serum Testosterone in Men With Acute Ischemic Stroke
Authors: Jeppesen Lise Leth , Jørgensen Henrik Stig , Nakayama Hirofumi , Raaschou Hans Otto , Olsen Tom Skyhøj , Winther Kaj
Published: June 2011

Abstract
Serum levels of total and free testosterone and 17β-estradiol were determined in 144 men with acute ischemic stroke and 47 healthy male control subjects. Blood samples from patients were drawn a mean of 3 days after stroke onset and also 6 months after admission in a subgroup of 45 patients. Initial stroke severity was assessed on the Scandinavian Stroke Scale and infarct size by computed tomographic scan. Mean total serum testosterone was 13.8±0.5 nmol/L in stroke patients and 16.5±0.7 nmol/L in control subjects (
P
=.002); the respective values for free serum testosterone were 40.8±1.3 and 51.0±2.2 pmol/L (
P
=.0001). Both total and free testosterone were significantly inversely associated with stroke severity and 6-month mortality, and total testosterone was significantly inversely associated with infarct size. The differences in total and free testosterone levels between patients and control subjects could not be explained by 10 putative risk factors for stroke, including age, blood pressure, diabetes, ischemic heart disease, smoking, and atrial fibrillation. Total and free testosterone levels tended to normalize 6 months after the stroke. There was no difference between patients and control subjects in serum 17β-estradiol levels. These results support the idea that testosterone affects the pathogenesis of ischemic stroke in men.
Polymorphic Markers in Apolipoprotein C-III Gene Flanking Regions and Hypertriglyceridemia
Authors: Surguchov Andrei P. , Page Grier P. , Smith Louis , Patsch Wolfgang , Boerwinkle Eric
Published: June 2011

Hypertriglyceridemia and hyperlipidemia are common disorders associated with coronary artery disease and premature death. The proteins encoded by the apolipoprotein (apo) A-I/C-III/A-IV gene cluster are involved in the metabolism of both triglycerides and cholesterol. In a large sample of individuals from the ARIC study, six polymorphic markers were typed and plasma lipid values were measured to determine whether the well-established association between theSstI S2 allele in the 3′-untranslated region of the apo C-III gene and hypertriglyceridemia was due to disequilibrium with variation in the 5′ regulatory region of the apo C-III gene. TheSstI polymorphism was significantly associated with hypertriglyceridemia (P=.006) but not with carotid artery wall thickness, plasma apo C-III levels, or elevated cholesterol. The frequency of the S2 allele was 0.14 in those with high triglyceride levels and 0.05 in those with low triglyceride levels. None of the 5′ flanking polymorphisms were significantly associated with any of the plasma lipids studied. There was substantial linkage disequilibrium between theSstI polymorphism and each of the 5′ apo C-III polymorphisms; however, the significant association between the apo C-III haplotypes and hypertriglyceridemia (odds ratio, 4.0;P<.0001) was solely attributable to the effects of theSstI polymorphism (odds ratio, 3.96). As a part of these analyses, we also defined a unique haplotype that is inversely associated with the occurrence of hypertriglyceridemia, suggesting further molecular analyses of this important gene region.
Accumulation of HDL Apolipoproteins Accompanies Abnormal Cholesterol Accumulation in Schnyder's Corneal Dystrophy
Authors: Gaynor Paulette M. , Zhang Wei-Yang , Weiss Jayne S. , Skarlatos Sonia I. , Rodrigues Merlyn M. , Kruth Howard S.
Published: June 2011

Schnyder's corneal dystrophy is an autosomal dominant disorder that results in clouding of the central cornea and premature development of peripheral arcus in the cornea. Previous studies showed that abnormal lipid accumulation is the basis for the corneal clouding. We examined whether apolipoproteins are involved in this disorder and characterized the lipid accumulation in the central portion of corneas removed from patients with Schnyder's dystrophy. Our findings show that cholesterol and phospholipid contents increased greater than 10-fold and 5-fold, respectively, in affected compared with normal corneas. In addition, the percentage of cholesterol that was unesterified (63% versus 50%) and the molar ratio of unesterified cholesterol to phospholipid (1.5 versus 0.5) were higher in affected compared with normal corneas. Large multilamellar vesicles and electron-dense granules (100 to 300 nm in diameter) as well as cholesterol crystals accumulated in the extracellular matrix of affected corneas. Immunohistochemical analysis showed that apolipoprotein constituents of HDL (apoA-I, apoA-II, and apoE), but not apoB, a marker of LDL, accumulated in the affected cornea. Western blot analysis confirmed the increased amounts of these HDL apolipoproteins in affected corneas and showed that the apparent molecular weights of the apolipoproteins were normal. Our findings show for the first time that HDL apolipoproteins accumulate in the corneas of patients with Schnyder's corneal dystrophy. Thus, this disorder influences the metabolism of HDL in the corneas of these patients.
Localization of Lipoprotein(a) in a Monkey Model of Rapid Neointimal Growth
Authors: Ryan Michael J. , Emig Laura L. , Hicks Gary W. , Ramharack Randy , Spahr Mark A. , Kreick Jeffrey S. , Brammer David W. , Chien Alexander J. , Keiser Joan A.
Published: June 2011

Lipoprotein(a) [Lp(a)] has been proposed as a restenosis risk factor, but it is not known if Lp(a) is present in the injured arterial wall during the initial neointimal growth. The purpose of this study was to determine if Lp(a) is incorporated into the vessel wall during rapid neointimal formation after arterial injury in primates. In this model, distention of the iliac artery with an angioplasty catheter caused focal breaks in the internal elastic lamina (IEL) in 80% of the vessels and extensive IEL fragmentation with medial disruption in 20% of the vessels. Neointimal growth was noted in all injured arteries; thrombus formation was noted in 40% of the vessels. Based on morphometric measurements, injured arteries had neointimal areas of 0.41±0.05 (n=4) and 0.83±0.23 (n=6) mm
2
at 14 and 28 days after injury, respectively. Control arteries had an intact IEL and a monolayer of intimal cells. Lp(a) localization was examined histologically by using a mouse monoclonal anti-Lp(a) antibody. Lp(a), found in all injured arteries, was localized primarily in the neointima in 50% of the vessels. In the subset of vessels with evidence of thrombus formation, intense Lp(a) immunostaining was associated with the thrombus. Lp(a) was specific to injured arteries as uninjured vessels did not stain. In addition, staining was not seen with a negative control, a nonspecific mouse IgG
1
antibody. The presence of Lp(a) at the site of rapid neointimal growth supports a role for this lipoprotein in the response to vascular injury after balloon angioplasty.
Hepatic Lipase Gene Polymorphisms Influence Plasma HDL Levels
Authors: Murtomäki Sanna , Tahvanainen Esa , Antikainen Marjatta , Tiret Laurence , Nicaud Viviane , Jansen Hans , Ehnholm Christian
Published: June 2011

Abstract
Hepatic lipase (HL), a triglyceride lipase found in liver, adrenals, testes, and ovaries, takes part in the uptake, remodeling, and function of lipoproteins including HDL, as well as VLDL and chylomicrons. In the present study, the genotype distribution of five HL polymorphisms (−C480T, V133V, T202T, L334F, T457T) and their association to plasma lipid values were investigated. The study participants included 92 students with paternal history of myocardial infarction before the age of 55 and 194 matched control subjects, ie, the Finnish participants of the European Atherosclerosis Research Study (EARS). The allele T of the HL polymorphism −C480T showed an association with elevated HDL, apoA-I, and LpA-I values (ANOVA
P
<.01). No difference in genotype distribution was observed in the offspring with and without paternal history of myocardial infarction.
Postprandial Elevation of ApoB-48-Containing Triglyceride-Rich Particles and Retinyl Esters in Normolipemic Males Who Smoke
Authors: Mero Niina , Syvänne Mikko , Eliasson Björn , Smith Ulf , Taskinen Marja-Riitta
Published: June 2011

Abstract
Smokers have an increased risk for coronary artery disease (CAD), which can only partly be explained by fasting lipoprotein changes. Recent studies have indicated that smokers express metabolic abnormalities characteristic of insulin resistance syndrome. A preliminary study reported an increased postprandial triglyceride (TG) response in smokers compared with nonsmokers. To investigate the effect of smoking on postprandial lipemia, a fat-rich mixed meal (837 kcal, 63 g of fat) was served to 12 healthy smokers and 12 controls with similar fasting lipoprotein profiles, body composition, and lifestyles. Blood was drawn before and 3, 4, 6, and 8 hours postprandially, and triglyceride-rich lipoprotein (TRL) fractions (chylomicrons, VLDL1, VLDL2, and IDL) were separated with density gradient ultracentrifugation. Pre- and postprandial TG, retinyl esters (RE), apolipoprotein B-48 (apoB-48) and B-100 (apoB-100) were measured in each fraction. Smokers showed a significantly increased postprandial TG response in chylomicrons, VLDL1, and VLDL2. The areas under the incremental curve (AUIC) of apoB-48 in chylomicrons (2.83±0.84 versus 0.56±0.17;
P
<.05) and VLDL1 (10.17±1.96 versus 2.95±2.44;
P
=<.01) were markedly higher in smokers than in controls. Changes of RE responses of all TRL fractions were consistent with those of apoB-48. Postprandial apoB-100 concentrations and lipolytic enzymes were similar between the two groups. In conclusion, smokers have the syndrome of impaired TG tolerance because of defective clearance of chylomicrons and their remnants. Prolonged residence time of atherogenic remnant particles may constitute a significant risk factor for CAD in smokers.
Tissue Factor Expression on Macrophages in Coronary Plaques in Patients with Unstable Angina
Authors: Kaikita Koichi , Ogawa Hisao , Yasue Hirofumi , Takeya Motohiro , Takahashi Kiyoshi , Saito Taro , Hayasaki Kazuya , Horiuchi Kenji , Takizawa Akinori , Kamikubo Yuichi , Nakamura Shin
Published: June 2011

Abstract
Tissue factor is a membrane-bound glycoprotein that functions in the extrinsic pathway of blood coagulation by acting as a cofactor for factor VII, and the resulting complex leads to thrombin production in vivo. The purpose of the present study is to determine whether macrophages express tissue factor in human coronary atherosclerotic plaques. We examined directional coronary atherectomy specimens from 24 patients with unstable angina and 23 with stable exertional angina. In these specimens, macrophages were detected in 22 (92%) of 24 patients with unstable angina versus 12 (52%) of 23 with stable exertional angina (
P
=.003). The percentage of macrophage infiltration area was significantly larger in patients with unstable angina than in those with stable exertional angina (17±3% versus 6±2%,
P
=.008). The immunohistochemical double staining revealed the expression of tissue factor on macrophages in 18 (75%) of 24 patients with unstable angina versus 3 (13%) of 23 with stable exertional angina (
P
<.0001). Thrombus was identified in 20 (83%) of 24 patients with unstable angina versus 12 (52%) of 23 with stable exertional angina (
P
=.02). Fibrin deposition was mainly observed around macrophages expressing tissue factor in the patients with unstable angina. We have shown that tissue factor expression on macrophages was more frequent in coronary atherosclerotic plaques in patients with unstable angina. Tissue factor expressed on macrophages may play an important role in the thrombogenicity in coronary atherosclerotic plaques of these patients.
Role of Activin-A and Follistatin in Foam Cell Formation of THP-1 Macrophages
Authors: Kozaki Koichi , Akishita Masahiro , Eto Masato , Yoshizumi Masao , Toba Kenji , Inoue Satoshi , Ishikawa Michiro , Hashimoto Masayoshi , Kodama Tatsuhiko , Yamada Nobuhiro , Orimo Hajime , Ouchi Yasuyoshi
Published: June 2011

AbstractMacrophage (Mφ) foam cell formation is a characteristic event that occurs in the early stage of atherosclerosis. To examine the roles of activin-A, a member of the transforming growth factor-β superfamily, and follistatin, the binding protein for activin-A, in Mφ function, we investigated their effects on foam cell formation of THP-1 Mφs. When THP-1 Mφs were treated with activin-A (5 nmol/L), foam cell formation and cellular cholesteryl ester accumulation were decreased. This downregulation was paralleled by a reduction in cell association and degradation of acetylated LDL. The inhibitory effect of activin-A on cell association and degradation was dose dependent, and the effect was blocked by concomitant addition of follistatin. Activin-A (5 nmol/L) also decreased the Bmax for acetylated LDL and scavenger receptor mRNA expression. Follistatin showed an effect opposite to that of activin-A and promoted Mφ foam cell formation and cellular cholesteryl ester accumulation. It increased binding, cell association, and degradation of acetylated LDL and upregulated scavenger receptor mRNA expression. Because follistatin is the binding protein for activin-A, follistatin’s effect is considered to be mediated by blocking the inhibitory effect of intrinsic activin-A. These results indicate that activin-A inhibits and follistatin promotes Mφ foam cell formation by regulating scavenger receptor mRNA expression. We conclude that activin-A and follistatin play important roles in the process of atherosclerosis by regulating Mφ foam cell formation.
Expression and Function of Recombinant Endothelial NO Synthase in Coronary Artery Smooth Muscle Cells
Authors: Kullo Iftikhar J. , Schwartz Robert S. , Pompili Vincent J. , Tsutsui Masato , Milstien Sheldon , Fitzpatrick Lorraine A. , Katusic Zvonimir S. , O’Brien Timothy
Published: June 2011

Abstract
Smooth muscle cells (SMCs) play a key role in the pathogenesis of vascular diseases. The objectives of this study were to determine whether transfer of recombinant endothelial nitric oxide synthase (eNOS) gene to porcine coronary artery smooth muscle cell (CSMCs) would result in expression of a functional enzyme and to assess the effect of expression of eNOS on cell proliferation. CSMCs were transduced in vitro with adenoviral vectors encoding cDNA for eNOS (AdeNOS) and β-galactosidase (AdβGal). In contrast to AdβGal- or sham-transduced cells, CSMCs transduced with AdeNOS stained positive with the NADPH-diaphorase stain, acquired calcium-dependent NOS activity (measured by the conversion of [
3
H]
l
-arginine to [
3
H]
l
-citrulline), had increasing cyclic 3′,5′ cGMP levels with increasing concentrations of the vector, and produced increased amounts of nitrite. cGMP production by AdeNOS-transduced cells was augmented by increasing intracellular levels of the eNOS cofactor tetrahydrobiopterin. CSMCs transduced with AdeNOS showed diminished serum-stimulated DNA synthesis as measured by thymidine uptake. Cell proliferation was diminished in AdeNOS-transduced CSMCs as assessed by cell counts 3 and 6 days after serum stimulation of quiescent CSMCs. The present study demonstrates that adenovirus-mediated gene transfer of eNOS to CSMCs results in the expression of a functional enzyme whose activity can be augmented by increasing intracellular levels of tetrahydrobiopterin. Expression of recombinant eNOS in CSMCs results in inhibition of serum-stimulated DNA synthesis and cell proliferation. These findings imply that eNOS gene transfer to SMCs may be a unique mode of increasing local NO production in the arterial wall.
The Heterozygous 20210 G/A Prothrombin Genotype Is Associated With Early Venous Thrombosis in Inherited Thrombophilias and Is Not Increased in Frequency in Artery Disease
Authors: Ferraresi P. , Marchetti G. , Legnani C. , Cavallari E. , Castoldi E. , Mascoli F. , Ardissino D. , Palareti G. , Bernardi F.
Published: June 2011

Abstract
A genetic variation in the 3′-untranslated region of the prothrombin mRNA (20210 G/A) has recently been reported to be associated with elevated plasma prothrombin levels and with an increased incidence of venous thrombosis. We determined the frequency of this mutation, the detection of which was improved by allele-specific amplification of exon 14 and by denaturing gradients (denaturing gradient gel electrophoresis), in cohorts of patients affected by venous thrombosis (n=132) or by coronary or cerebrovascular diseases (n=195) and in normal subjects from various populations. An overlapping frequency of the heterozygous genotype (4%) was found in normal subjects from Italy and Cyprus, and no carrier was detected in 40 subjects of Indian or Somali origin. The 20210 GA heterozygous genotype was not increased in frequency in patients with arterial disease. In contrast, the GA genotype was associated (
P
=.007) with venous thrombosis both in simple heterozygotes (16%) with a family history of thrombosis as well as in double heterozygotes (14%) for other known thrombophilic defects. A synergic interaction between the prothrombin 20210 GA genotype and the factor V Leiden mutation, both potentially affecting the prothrombinase complex, was suggested by the early onset of thrombosis (median age 22 years) in doubly heterozygous patients. The association of the 20210 A allele with higher prothrombin levels was confirmed in the Italian population. However, the prothrombin assay does not allow an efficient preselection of patients for the DNA analysis.
Beneficial Effects of Alcohol Withdrawal on LDL Particle Size Distribution and Oxidative Susceptibility in Subjects With Alcohol-Induced Hypertriglyceridemia
Authors: Ayaori Makoto , Ishikawa Toshitsugu , Yoshida Hiroshi , Suzukawa Michio , Nishiwaki Masato , Shige Hideki , Ito Toshimitsu , Nakajima Kei , Higashi Kenji , Yonemura Atsushi , Nakamura Haruo
Published: June 2011

Abstract
LDL subclass pattern B, reported to have a higher prevalence in hypertriglyceridemics (HTGs), is considered to be associated with an increased risk for coronary artery disease, and the small dense LDL characteristic of this pattern is susceptible to oxidative modification. Alcohol is considered one of the most frequent causes of increases in plasma triglyceride (TG) levels. We investigated the effects of alcohol withdrawal on LDL subclass distribution and oxidizability in drinkers with different plasma TG levels. Thirty-seven male subjects with relatively heavy alcohol-consumption habits were divided into four groups; normotriglyceridemic (NTG)/withdrawal (n=11), NTG/control (n=8), hypertriglyceridemic (HTG)/withdrawal (n=10), and HTG/control (n=8). Both withdrawal groups abstained form alcohol for 4 weeks, while the control subjects maintained their usual intake of alcohol. Peak LDL particle diameter (PPD) was smaller in the combined HTG groups than in the combined NTG groups before abstinence, although PPD increased significantly (
P
<.01) from 25.5 to 26.1 nm in the HTG/withdrawal group. Before abstinence, lag times preceding LDL oxidation in the combined HTG groups were shorter than in the combined NTG groups; after withdrawal, lag time was prolonged significantly (
P
<.01) from 49.9 to 57.3 minutes in the HTG-withdrawal group. No significant changes in PPD and lag time were observed in the other three groups. Significant correlations (
P
<.05) were observed between the change (Δ) in lag time and ΔTG and between Δlag time and ΔPPD. We conclude that in alcohol-induced HTG subjects, alcohol withdrawal has beneficial effects on the LDL profile by shifting the particle size from smaller to larger and decreasing its susceptibility to oxidation.
Effect of Iron Overload and Iron Deficiency on Atherosclerosis in the Hypercholesterolemic Rabbit
Authors: Dabbagh Alya J. , Shwaery Glenn T. , Keaney John F. , Frei Balz
Published: June 2011

Abstract
It has been suggested that iron plays an important role in the pathogenesis of atherosclerosis, primarily by acting as a catalyst for the atherogenic modification of LDL. Although some epidemiological data suggest that high stored iron levels are an independent risk factor for coronary artery disease and that iron has been detected in both early and advanced atherosclerotic lesions, the evidence is often contradictory and inconclusive. We used the New Zealand White rabbit to investigate the effects of iron overload (FeO) and iron deficiency (FeD) on atherosclerosis. Groups of 7 rabbits were either iron loaded by injections of iron dextran (FeO group), iron depleted by phlebotomy (FeD group), or given injections of saline (control group) for a total of 9 weeks. All rabbits were fed a chow diet containing 1% (wt/wt) cholesterol for the last 6 weeks of the study. Iron and antioxidant status and cholesterol levels were assayed in plasma before cholesterol feeding (week 3) and at the time that the rabbits were killed (week 9). In addition, the susceptibility of LDL to oxidation was measured and pathological examination of the aortic arch and thoracic aorta performed at the end of the study. FeD significantly decreased the levels of blood hemoglobin, serum iron, and transferrin saturation compared with controls. Conversely, FeO significantly increased transferrin Fe saturation. FeO but not FeD decreased plasma cholesterol levels compared with control animals both before (
P
<.05) and after (
P
=.055) cholesterol feeding. Neither FeO nor FeD had a significant effect on the levels of antioxidants and lipid peroxidation products in plasma and aortic tissue or on the susceptibility of LDL to ex-vivo oxidation. FeO significantly decreased aortic arch lesion formation by 56% compared with controls (
P
<.05), whereas FeD had no significant effect. These results indicate that in this animal model, FeO decreases rather than increases atherosclerosis, likely because iron dextran exerts a hypocholesterolemic effect. Our data do not support the hypotheses that elevation of Fe stores increases or that a reduction of Fe stores by phlebotomy decreases the risk of coronary artery disease.
HDL Phospholipid Content and Composition as a Major Factor Determining Cholesterol Efflux Capacity From Fu5AH Cells to Human Serum
Authors: Fournier Natalie , Paul Jean-Louis , Atger Véronique , Cogny Anne , Soni Théophile , de la Llera-Moya Margarita , Rothblat George , Moatti Nicole
Published: June 2011

Abstract
The relationships of cell cholesterol efflux to HDL phospholipid (PL) content and composition in human serum were analyzed in two groups of subjects selected on the basis of their HDL cholesterol (HDL-C) levels: a norm-HDL group (1.10 mmol/L<HDL-C<1.50 mmol/L) and a high-HDL group (HDL-C>1.75 mmol/L). In the high-HDL group, the relative fractional efflux was significantly higher than in the norm-HDL group, and in both groups, fractional efflux was correlated with a number of lipoprotein parameters, the best correlation and the only one that remained significant after multivariate analysis being with HDL phospholipid (HDL-PL). Analysis of the HDL-PL subclasses revealed that HDL in the high-HDL sera was enriched with phosphatidylethanolamine (HDL-PE) and relatively deficient in sphingomyelin (HDL-SM) compared with norm-HDL sera. Moreover, the fractional efflux values in the high-HDL group were negatively correlated with the proportion of HDL-PE (
r
=−.64,
P
<.0001) and positively correlated with the proportion of HDL-SM (
r
=.43,
P
<.01). Thus, this study provides evidence that HDL-PL concentration can be used to predict the capacity of serum to accept cellular cholesterol. Among the differences described between norm-HDL and high-HDL sera, the variability in PE to SM ratio might reflect changes in serum cholesterol acceptors that modulate the first step of reverse cholesterol transport.
Etiologic Heterogeneity of Hyperapobetalipoproteinemia (HyperapoB)
Authors: Juo Suh-Hang Hank , Beaty Terri H. , Kwiterovich Peter O.
Published: June 2011

Abstract
Hyperapobetalipoproteinemia (hyperapoB) is a common familial lipoprotein disorder associated with premature coronary artery disease (CAD). HyperapoB is characterized by an increased number of small, dense LDL particles. Patients with hyperapoB may be normotriglyceridemic (normoTG) or hypertriglyceridemic (hyperTG). We tested the hypothesis that a major locus controls the hyperapoB phenotype by using data from 1035 participants in 145 families enriched for premature CAD. Segregation analysis was conducted, and results suggest etiologic heterogeneity in these families. Families (n=55) with one or more hyperTG hyperapoB individuals strongly supported mendelian recessive inheritance of hyperapoB. Under this mendelian model, individuals with the high-risk genotype had a baseline risk of 0.78, but parental and spouse’s hyperapoB phenotypes did influence the probability of displaying hyperapoB. Low-risk genotypes had virtually no risk of displaying hyperapoB. The other subgroup of families (n=72), in which all hyperapoB individuals were normoTG, did not show any clear pattern of inheritance. Eighteen families did not have any hyperapoB individual. In the 55 families with hyperTG hyperapoB, diabetes was more prevalent in hyperapoB individuals (18.3% of hyperTG hyperapoB individuals, 9.6% of normoTG hyperapoB individuals) than in normal individuals (4.9%). Both hyperTG hyperapoB and normoTG hyperapoB phenotypes were significant predictors for blood pressure in the 55 families, but not in the total population. These associations further suggest a link between hyperapoB and the small, dense LDL syndromes. This study successfully demonstrated mendelian inheritance of the hyperapoB phenotype and also suggested etiologic heterogeneity of hyperapoB.
Interaction Between BTBR and C57BL/6J Genomes Produces an Insulin Resistance Syndrome in (BTBR × C57BL/6J) F
1
Mice
Authors: Ranheim Trine , Dumke Charles , Schueler Kathryn L. , Cartee Gregory D. , Attie Alan D.
Published: June 2011

Abstract
Insulin resistance is a common syndrome that often precedes the development of noninsulin-dependent diabetes mellitus (NIDDM). Both diet and genetic factors are associated with insulin resistance. BTBR and C57BL/6J (B6) mice have normal insulin responsiveness and normal fasting plasma insulin levels. However, a cross between these two strains yielded male offspring with severe insulin resistance. Surprisingly, on a basal diet (6.5% fat), the insulin resistance was not associated with fasting hyperinsulinemia. However, a 15% fat diet produced significant hyperinsulinemia in the male mice (twofold at 10 weeks;
P
<.05). At 10 weeks of age, visceral fat contributed approximately 4.3% of the total body weight in the males versus 1.8% in females. In the males, levels of plasma triacylglycerol and total cholesterol increased 40% and 30%, respectively, compared to females. Plasma free fatty acid concentrations were unchanged. Oral glucose tolerance tests revealed significant levels of hyperglycemia and hyperinsulinemia 15 to 90 minutes after oral glucose administration in the male mice. This was particularly dramatic in males on a 15% fat diet. Glucose transport was examined in skeletal muscles in (BTBR×B6)F
1
mice. In the nonhyperinsulinemic animals (females), insulin stimulated 2-deoxyglucose transport 3.5-fold in the soleus and 2.8-fold in the extensor digitorum longus muscles. By contrast, glucose transport was not stimulated in the hyperinsulinemic male mice. Hypoxia stimulates glucose transport through an insulin-independent mechanism. This is known to involve the translocation of GLUT4 from an intracellular pool to the plasma membrane. In the insulin-resistant male mice, hypoxia induced glucose transport as effectively as it did in the insulin-responsive mice. Thus, defective glucose transport in the (BTBR×B6)F
1
mice is specific for insulin-stimulated glucose transport. This is similar to what has been observed in muscles taken from obese NIDDM patients. These animals represent an excellent genetic model for studying insulin resistance and investigating the transition from insulin resistance in the absence of hyperinsulinemia to insulin resistance with hyperinsulinemia.
Copper Ions Promote Peroxidation of Low Density Lipoprotein Lipid by Binding to Histidine Residues of Apolipoprotein B100, But They Are Reduced at Other Sites on LDL
Authors: Wagner Peter , Heinecke Jay W.
Published: June 2011

Abstract
Oxidized LDL is implicated in the pathogenesis of atherosclerosis. A widely studied model for oxidation of the lipid in LDL involves Cu
2+
. Recent studies suggest that Cu
2+
may be reduced to Cu
1+
by α-tocopherol to initiate LDL lipid peroxidation. LDL demonstrates binding sites for Cu
2+
, but the nature of these binding sites, as well their role in promoting Cu
2+
reduction and lipid peroxidation, has not been established. In the current studies, we used diethylpyrocarbonate (DEPC) to modify the histidine residues of apolipoprotein B100, the major protein in LDL. First, we demonstrated that histidine residues were preferentially modified by DEPC under our experimental conditions. Then we monitored the kinetics of Cu
2+
-promoted oxidation of LDL and DEPC-modified LDL. In both cases, the progress curve of lipid peroxidation exhibited a lag phase and a propagation phase. However, when LDL was modified with DEPC, the length of the lag phase was prolonged whereas the rate of lipid peroxidation during the propagation phase was lower. Studies with LDL oxidized by 2,2′-azobis (2-amidinopropane) hydrochloride and phosphatidylcholine liposomes oxidized with hydroxyl radical established that DEPC was not acting simply as a nonspecific inhibitor of lipid peroxidation. DEPC treatment of LDL almost completely inhibited its ability to bind Cu
2+
. These observations suggest that peroxidation of the lipids in LDL can proceed with normal kinetics only when Cu
2+
binds preferentially to sites on apolipoprotein B100 that contain histidine residues. We also compared the kinetics of Cu
2+
reduction in the absence and presence of DEPC. There was no effect of DEPC modification on either the rate or extent of Cu
2+
reduction by LDL. Therefore LDL is likely to contain a second class of binding sites for Cu
2+
that does not involve histidine residues. Thus, LDL appears to contain at least two classes of Cu
2+
-binding sites: histidine containing sites, which are responsible in part for promoting lipid peroxidation during the propagation phase, and sites at which Cu
2+
is reduced without binding to histidine.
HDL-Induced Prostacyclin Release in Smooth Muscle Cells Is Dependent on Cyclooxygenase-2 (Cox-2)
Authors: Viñals M. , Martínez-González J. , Badimon J. J. , Badimon L.
Published: June 2011

Abstract
Cyclooxygenase-1 (Cox-1) and Cox-2 are key enzymes in the conversion of arachidonic acid to prostaglandins and other eicosanoids. We studied the effects of plasma HDL and LDL on the synthesis of prostacyclin, Cox-1/Cox-2 mRNA, and protein expression by rabbit aortic smooth muscle cells. Prostacyclin synthesis was measured by enzyme immunoassay (EIA) of the stable metabolite of prostacyclin (PGI
2
), 6-keto-prostaglandin F
1α
. HDL (150 μg/mL) induced release of PGI
2
to values 3.46±0.3-fold above control. Incubations with LDL did not induce release of PGI
2
.
N
-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide (NS-398), a selective irreversible Cox-2 inhibitor, blocked the HDL-induced PGI
2
synthesis. Cycloheximide, actinomycin D, and dexamethasone downregulated HDL-induced PGI
2
synthesis; therefore, HDL induced de novo synthesis of protein and Cox-2 mRNA. In addition, Northern blot analyses did not reveal differences in Cox-1 mRNA levels between control and HDL-treated cells, whereas Cox-2 mRNA levels were significantly increased in treated cells. Western blot analysis also showed an increase in the levels of Cox-2 protein. Therefore, the effects of HDL on PGI
2
synthesis are mediated via upregulation of Cox-2 expression.
Lipoprotein Heterogeneity and Apolipoprotein B Metabolism
Authors: Packard Chris J. , Shepherd James
Published: June 2011

Abstract
The apolipoprotein B containing lipoproteins VLDL, IDL, and LDL exhibit variation in their structure, function, and metabolism. These major lipoprotein classes can be fractionated into apparently discrete components by density gradient centrifugation or affinity chromatography. Examination of the behavior of subfractions in vivo reveals the presence of metabolic channels within the VLDL-LDL delipidation cascade so that the pedigree of a lipoprotein in part determines its metabolic fate. Evidence from VLDL and LDL apoB turnovers together with epidemiological data allows the construction of a quantitative model for the generation of small, dense LDL. This lipoprotein subspecies is one component of the dyslipidemic syndrome known as the atherogenic lipoprotein phenotype, a common disorder in those at risk for coronary heart disease. Understanding lipoprotein heterogeneity is an essential step in the further discovery of the pathogenesis of atherosclerosis and in the tailoring of pharmacologic treatment for subjects at risk.
Early Administration of Intravenous Magnesium Inhibits Arterial Thrombus Formation
Authors: Ravn Hanne Berg , Kristensen Steen Dalby , Hjortdal Vibeke Elisabeth , Thygesen Kristian , Husted Steen Elkjær
Published: June 2011

Abstract
An antiplatelet effect of magnesium has been demonstrated in vitro and ex vivo, and this effect may be advantageous in patients with acute myocardial infarction to inhibit reocclusion after coronary angioplasty or thrombolysis. We investigated the antithrombotic in vivo effect of intravenous magnesium in a placebo-controlled, blinded study in 46 male Wistar rats. Thrombus formation was induced by standardized arteriotomy of the femoral artery and partial inversion of the vessel wall to produce a thrombogenic area. The vessel was transilluminated and visualized dynamically by in vivo microscopy. Thrombus area was measured every minute for 30 minutes after removal of the vessel clamp by image analysis techniques, and the number of visible emboli was registered. Animals were randomized into three groups: groups 1 and 2 received saline (control group, n=15) or MgSO
4
(Mg-early group, n=15), respectively, during the entire infusion period. In group 3 intravenous saline was given during preparation of the arteriotomy followed by infusion of MgSO
4
(Mg-late group, n=16) from 10 minutes after removal of the vessel clamp. Thrombus area was significantly reduced by 75% in the Mg-early group (
P
<.005) but not in the Mg-late group compared with the control group. Mean number of emboli was reduced during magnesium infusion. The serum magnesium level increased to 2.2 (2.1 to 2.5) and 3.5 (3.0 to 4.2) mmol/L after infusion in the Mg-late and the Mg-early group, respectively. In the present study, intravenous infusion of MgSO
4
significantly reduced thrombus formation in vivo but only when it was given before reperfusion. The antithrombotic effect of magnesium may be utilized in patients with acute myocardial infarction to reduce the rate of reocclusion. Magnesium infusion may also be of value in elective arterial angioplasty, but this option has not been investigated in clinical trials. However, correct timing of magnesium administration is critical to obtain an efficient antithrombotic effect.
Tumor Necrosis Factor-α Activates Smooth Muscle Cell Migration in Culture and Is Expressed in the Balloon-Injured Rat Aorta
Authors: Jovinge Stefan , Hultgårdh-Nilsson Anna , Regnström Jan , Nilsson Jan
Published: June 2011

AbstractIn experimental models of atherosclerosis, activation of smooth muscle cell (SMC) migration from the media to the intima is preceded by intimal accumulation of inflammatory cells, suggesting that cytokines may be involved in this process. The present study demonstrates that tumor necrosis factor-α (TNF-α) regulates cytoskeletal organization of SMCs by inducing depolymerization of actin stress fibers and dispersion of vinculin from sites of focal adhesion and stimulates the migration of cultured human SMCs in a dose-dependent manner. Moreover, TNF-α induces rapid activation of the c-ets-1 gene, which codes a transcription factor known to regulate enzymes important for matrix degradation during cell migration. Balloon catheter injury of the rat femoral artery resulted in medial expression of TNF-α within 6 hours. This expression appeared to be localized to SMCs and remained elevated until SMCs began to migrate into the intima 7 days after injury. These findings demonstrate that TNF-α has a stimulatory effect on SMC migration and suggest that TNF-α may be involved in the intimal recruitment of SMCs during plaque formation.
The Thrombomodulin/Protein C/Protein S Anticoagulant Pathway Modulates the Thrombogenic Properties of the Normal Resting and Stimulated Endothelium
Authors: Cadroy Y. , Diquélou A. , Dupouy D. , Bossavy J.P. , Sakariassen K.S. , Sié P. , Boneu B.
Published: June 2011

Abstract
We investigated the role of the thrombomodulin (TM)/protein C/protein S anticoagulant pathway in modulating the thrombogenic properties of the endothelium. Endothelial cells (ECs) were placed in parallel-plate flow chambers and exposed to nonanticoagulated human blood at a venous wall shear rate (50 s
−1
). Fibrin deposition on resting ECs treated with a control IgG1 was negligible. In contrast, a significant amount of fibrin deposited when TM expression was specifically suppressed by >95% by preincubating ECs with an anti-TM IgG1. Similarly, fibrin deposited on interleukin 1–stimulated ECs, but the fibrin deposition was further increased threefold with anti-TM IgG1. Comparable results were found when ECs were perfused at 650 s
−1
. When TM surface activity was enhanced by 150% by treating ECs with active phorbol ester (4′-phorbol 12-myristate 13-acetate; PMA), the deposition of fibrin was 30% lower than on ECs not pretreated with PMA. Finally, fibrin deposition on stimulated ECs was significantly higher in 11 untreated patients with well-characterized deficiencies of protein C or S or heterozygous factor V Leiden mutation than in 11 healthy individuals, and it was significantly correlated to basal plasma levels of thrombin-antithrombin complexes. Thus, this study underlines the central role of the TM/protein C/protein S pathway in modulating the thrombogenic status of resting and stimulated ECs and indicates that basal coagulation system markers may be helpful in monitoring patients presenting a disorder of this anticoagulant pathway.
Fibrinolytic Function After Dietary Supplementation With ω3 Polyunsaturated Fatty Acids
Authors: Toft Ingrid , Bønaa Kaare H. , Ingebretsen Ole C. , Nordøy Arne , Jenssen Trond
Published: June 2011

Abstract
Hypertension is associated with derangements in glucose and lipid metabolism. Increased levels of plasminogen activator inhibitor type 1 (PAI-1) are thought to potentiate the development of coronary events in this condition. Fish oil (ω3 polyunsaturated fatty acids [PUFAs]) have lipid-lowering effects, but the cardioprotective potential has been questioned because fish oil has been found to increase PAI-1 activity. This study was performed to determine the effects of ω3 PUFAs on the fibrinolytic function in hypertension. Seventy-eight persons with untreated hypertension were included in a 16-week, double-blind, randomized, controlled intervention study with 4 g/d of eicosapentaenoic and docosahexaenoic acids or corn oil placebo. Plasma PAI-1 activity, tissue plasminogen activator (tPA) activity, levels of fibrinogen and factor VII
c
, and platelet count were measured before and after intervention (mean±SE). PAI-1 activity changed similarly in the fish oil and corn oil groups (1.8±1.0 U/mL versus 3.5±1.2 U/mL,
P
=.25), as did tPA (−0.02±0.02 IU/mL versus −0.13±0.03 IU/mL,
P
=.28), levels of factor VII
c
(6±5% versus 5±4%,
P
>.3), and platelet count (2±7×10
9
/L versus 3±5×10
9
/L,
P
>.3). None of these variables changed from pretreatment levels during fish oil intake. Fibrinogen levels increased significantly both during fish oil (0.6±0.1 g/L,
P
=.0001) and corn oil (0.4±0.1 g/L,
P
=.002) intake. There was no between-group difference (
P
>.3). In conclusion, a daily intake of 4 g ω3 PUFAs does not affect PAI-1 and tPA activity in persons with hypertension. A modest increase in fibrinogen levels was observed after both fish oil and corn oil intake.
Five Frequent Polymorphisms of the PAI-1 Gene
Authors: Henry Mireille , Chomiki Nathalie , Scarabin Pierre Yves , Alessi Marie Christine , Peiretti Franck , Arveiler Dominique , Ferrières Jean , Evans Alun , Amouyel Philippe , Poirier Odette , Cambien François , Juhan-Vague Irène
Published: June 2011

Abstract
The main function of plasminogen activator inhibitor type 1 (PAI-1) is to decrease fibrinolysis, which leads to fibrin accumulation. An elevated plasma PAI-1 concentration has been identified as a risk factor for the development of myocardial infarction, and an association between 1 polymorphism of the PAI-1 promoter and plasma PAI-1 levels has been described. Our aim was to identify new polymorphisms in the PAI-1 gene and to further examine the relationship between PAI-1 genotypes and circulating PAI-1 levels. We report the presence of 4 new polymorphisms that were identified by nonisotopic single-strand conformational polymorphism analysis followed by sequencing. These polymorphisms were investigated in relation to PAI-1 levels in a sample of 256 healthy men, aged 50-59 years, from France and Northern Ireland. Two G/A substitutions were detected at positions −844 and +9785. The former is in strong positive linkage disequilibrium with the previously described 4G/5G polymorphism at position −675. Two polymorphisms in the 3′ untranslated region were identified. One corresponds to a T/G substitution at position +11 053 and is in negative linkage disequilibrium with the G/A substitution (+9785). The other is a 9-nucleotide insertion/deletion located between nucleotides +11 320 and +11 345 in a threefold-repeated sequence. This polymorphism is in strong positive linkage disequilibrium with the G/A substitution (+9785). The overall heterozygosity provided by the 5 PAI-1 polymorphisms (including the 4 new variants and the 4G/5G polymorphism) was .77. No significant association was found between PAI activity and genotypes; furthermore, the well known associations between PAI activity and body mass index, serum triglycerides, or insulin were homogeneous according to PAI-1 genotypes.