bluuebunny/crossref_metadata_2025 huggingface dataset:
Apolipoprotein B and E Basic Amino Acid Clusters Influence Low-Density Lipoprotein Association with Lipoprotein Lipase Anchored to the Subendothelial Matrix
Authors: Saxena Uday , Auerbach Bruce J. , Ferguson Erika , Wölle Joachim , Marcel Yves L. , Weisgraber Karl H. , Hegele Robert A. , Bisgaier Charles L.
Published: June 2011

Abstract
Lipoprotein accumulation in the subendothelial matrix is an important step in atherogenesis. We have previously shown that addition of lipoprotein lipase (LPL) markedly increased binding of apolipoprotein B (apoB)–containing lipoproteins to an endothelial cell–derived matrix, and this enhanced lipoprotein binding was inhibited by apoE. In the present studies we examined the role of various regions of apoB in the binding of LDL to LPL-containing endothelial cell matrix and the ability of various apoE domains to decrease lipoprotein retention. We studied three apoB epitope-specific monoclonal antibodies for their ability to block the binding of
125
I-LDL to LPL-containing matrix. Of these, monoclonal antibody 4G3, which recognizes an arginine-containing epitope in apoB, was the most effective in reducing LDL binding. Chemical modification of LDL apoB lysines or arginines markedly reduced the ability of the lipoprotein to block the binding of
125
I-LDL to LPL-containing matrix, suggesting that apoB positively charged amino acids are involved in the interaction. Furthermore, polyarginine or polylysine markedly decreased
125
I-LDL binding to LPL-containing matrix, whereas polyleucine was ineffective. These data suggest that apoB positively charged regions are important in LDL binding. To explore the role of charge modifications on apoE by single arginine-cysteine interchanges, we examined the effects of the three major human apoE isoforms (apoE2, apoE3, and apoE4). ApoE3 was the most effective in decreasing
125
I-LDL retention, followed by apoE4; apoE2 was the least effective. Similarly, apoE2-containing HDL was much less effective than apoE3-containing HDL in decreasing
125
I-LDL retention. Therefore, both cysteine for arginine substitutions at amino acids 112 and 158, known to markedly reduce apoE binding to the LDL receptors, also had significant effects on the ability of this apoE isoform to displace LDL bound to LPL. Two peptides generated by thrombin cleavage of apoE3 both were able to decrease
125
I-LDL binding, indicating the presence of multiple sites within apoE that could participate in the inhibitory effect. We conclude that positively charged regions on apoB are responsible for the binding of LDL to LPL-containing matrix and that similar regions of positive charge in apoE allow it to compete and decrease the retention of LDL.
Apolipoprotein E4 Phenotype Is Not an Important Risk Factor for Coronary Heart Disease or Stroke in Elderly Subjects
Authors: Kuusisto Johanna , Mykkänen Leena , Kervinen Kari , Kesäniemi Y. Antero , Laakso Markku
Published: June 2011

Abstract
The allele e4 (apo e4) of apolipoprotein E (apo E) has been associated with an increased risk for coronary heart disease (CHD) in cross-sectional studies in middle-aged subjects. We investigated the risk of CHD and stroke with respect to the number of apo e4 alleles in a prospective study of a Finnish nondiabetic cohort including 1067 subjects 65 to 74 years old at baseline. During the 3.5-year follow-up, CHD mortality was 2.8%, total CHD incidence 6.9%, and the cumulative occurrence of CHD (prevalence at baseline and the 3.5-year incidence combined) 17.0%. The incidence of stroke was 3.4%, and the cumulative occurrence of stroke was 6.0%. The CHD mortality was 3.4% in subjects with no apo e4 allele (n=734), 1.7% in those with one apo e4 allele (n=296), and 0% in subjects with two apo e4 alleles (n=37) (
P
=NS between the three groups). The incidence of CHD according to the number of apo e4 alleles was 6.9% (no apo e4 alleles), 7.4% (one apo e4 allele), and 2.7% (two apo e4 alleles), and the cumulative occurrence of CHD was 16.5%, 18.6%, and 13.5%, respectively (
P
=NS). The incidence of stroke was 3.8% in subjects with no apo e4 allele, 2.7% in those with one apo e4 allele, and 0% in those with two apo e4 alleles (
P
=NS). The cumulative occurrence of stroke was 6.0%, 6.4%, and 2.7%, respectively (
P
=NS). In conclusion, in contrast to middle-aged subjects, the risk of cardiovascular disease in elderly subjects with apo e4 is not increased. Consequently, the allele e4 of apo E cannot be regarded as an important risk factor for CHD or stroke in the elderly.
Plasma Homocysteine Levels in Patients With Deep Venous Thrombosis
Authors: Amundsen Tore , Ueland Per Magne , Waage Anders
Published: June 2011

Abstract
Increased risk of arterial and venous thromboembolic disease is well documented in the homocystinuric patient. There is growing evidence that hyperhomocysteinemia is an independent risk factor for premature arteriosclerotic disease, including cerebral, peripheral, and coronary vascular diseases. So far no association has been established between hyperhomocysteinemia and venous thromboembolism.We studied 35 patients, young adults (age less than 56 years) with venographically and/or ultrasonographically verified deep venous thrombosis (DVT). Patients with coexisting diseases were excluded. Plasmahomocysteine levels before and after intake of methionine were measured 3 months or more after the time of diagnosis and compared with 39 control subjects. We found no significant difference in plasmahomocysteine levels between the young adults with deep venous thrombosis and control subjects. This indicates that hyperhomocysteinemia is not a frequent cause of DVT.
Dietary γ-Linolenic Acid Modulates Macrophage–Vascular Smooth Muscle Cell Interactions
Authors: Fan Yang-Yi , Ramos Kenneth S. , Chapkin Robert S.
Published: June 2011

AbstractMacrophages and smooth muscle cells (SMCs) are two of the major reactive cell types in atherosclerosis, a disease characterized by uncontrolled proliferation of SMCs. The present study was designed to determine how dietary oils containing γ-linolenic acid (GLA) (primrose oil [PO]) and long-chain n-3 fatty acids (fish oil) influence the ability of macrophages to modulate SMC DNA synthesis in vitro. Mice were fed one of four diets containing 10% (wt/wt) corn oil (CO), PO, fish oil–CO mix (FC; 9:1, wt/wt), or fish oil–PO mix (FP; 1:3, wt/wt) for 2 weeks. Resident peritoneal macrophages were isolated from these mice and seeded on a semipermeable membrane with a 30-kDa cutoff. Macrophages were preincubated with or without 50 μmol/L indomethacin (a cyclooxygenase inhibitor) or 50 μmol/L L655,238 (a 5-lipoxygenase inhibitor) for 30 minutes and subsequently cocultured with naive murine aortic SMCs grown on culture dishes. DNA synthesis in SMCs and prostaglandin formation in coculture supernatants were measured at the end of a 39-hour incubation period. SMC DNA synthesis was inhibited by 28% and 60% in PO and FP diets containing 10.1% and 8.2% GLA, respectively, relative to the control CO diet containing no GLA or long-chain n-3 fatty acid. A fourfold increase in the levels of PGE1, a potent antiproliferative eicosanoid derived from GLA, was observed in the PO and FP groups relative to the control CO group. Although PGE1levels were not different between the CO and FC dietary groups, 15% inhibition of SMC DNA synthesis, relative to that in mice fed the control CO diet, was observed in mice fed the FC diet containing 13.3% 20:5n-3 and 7.6% 22:6n-3 fatty acids. Macrophage inhibition of SMC DNA synthesis and proliferation in mice consuming GLA-enriched diets was blocked by indomethacin but not by L655,238. Addition of exogenous PGE1(100 nmol/L) reversed the effect of indomethacin. In experiments in which mice were fed increasing levels of GLA-containing triglycerides, the ability of macrophages to downregulate SMC proliferation was modulated in a dose-dependent fashion. These data indicate that macrophages isolated from animals consuming diets supplemented with dietary oils containing GLA reduce SMC DNA synthesis and proliferation in a cyclooxygenase-dependent manner and therefore may favorably modulate the atherogenic process.
Plasminogen Activator Expression in Human Atherosclerotic Lesions
Authors: Lupu Florea , Heim Dominik A. , Bachmann Fedor , Hurni Michel , Kakkar V. V. , Kruithof Egbert K. O.
Published: June 2011

Abstract
The plasminogen activator (PA) system may participate in the pathogenesis of atherosclerosis by modulating the turnover of intimal fibrin and extracellular matrix deposits and by contributing to intimal cell migration. We present an analysis of tissue-type PA (tPA) and urokinase-type PA (uPA) expression at three levels: mRNA by in situ hybridization, antigen by immunohistochemistry, and enzymatic activity by histoenzymology and zymography. For PA colocalization with cellular or matrix components, we used double immunofluorescence labeling in conjunction with confocal microscopy. In normal arteries, tPA antigen and mRNA were detected in endothelial cells and smooth muscle cells (SMCs). In atherosclerotic arteries, tPA antigen and mRNA were increased in intimal SMCs and in macrophage-derived foam cells of fibrofatty lesions. Part of the tPA was detected in the extracellular space and colocalized with fibrin deposits. uPA antigen and mRNA were detected in association with the intimal macrophages and SMCs. A particularly high uPA expression was noted on macrophages localized on the rims of the necrotic core. Moreover, using a novel histoenzymological assay as well as classic zymography, we revealed uPA-dependent lytic activity in the advanced lesions, whereas in normal arteries, only tPA-dependent activity was detected, mainly over the vasa vasorum. Also, strong tPA and uPA staining was detected in neomicrovessels of the plaques, suggesting that PAs may play a role in plaque angiogenesis. Our results suggest a local dynamic process of PA-dependent proteolysis in lesion areas that is associated with macrophages and SMCs. A better comprehension of these proteolytic mechanisms in advanced atherosclerotic plaques may provide the basis for therapeutic approaches for plaque stabilization.
Effects of Dexamethasone on the Synthesis, Degradation, and Secretion of Apolipoprotein B in Cultured Rat Hepatocytes
Authors: Wang Chuen-Neu , McLeod Roger S. , Yao Zemin , Brindley David N.
Published: June 2011

Abstract
Oversecretion of apoB and decreased removal of apoB-containing lipoproteins by the liver results in hyperapobetalipoproteinemia, which is a risk factor for atherosclerosis. We investigated how dexamethasone, a synthetic glucocorticoid, affects the synthesis, degradation, and secretion of apoB-100 and apoB-48. Primary rat hepatocytes were incubated with dexamethasone for 16 hours. Incorporation of [
35
S]methionine into apoB-48 and apoB-100 was increased by 36% and 50%, respectively, with 10 nmol/L dexamethasone, despite a 28% decrease of incorporation into total cell proteins. However, Northern blot analysis revealed that dexamethasone (1 to 1000 nmol/L) did not significantly alter the steady-state concentrations of apoB mRNA, suggesting that the net increase in apoB synthesis may involve increased translational efficiency. The intracellular retention and the rate and efficiency of apoB secretion were determined by pulse-chase experiments in which the hepatocytes were labeled with [
35
S]methionine for 10 minutes or 1 hour, and the disappearance of labeled apoB from the cells and its accumulation in the medium were monitored. Degradation of labeled apoB-100 after a 3-hour chase in both protocols was decreased from about 50% to 30%, whereas degradation of apoB-48 was decreased from 30% to 10% to 20% by treatment with 10 or 100 nmol/L dexamethasone. Additionally, the half-life of decay (time required for 50% of labeled cell apoB-100 to disappear from the peak of radioactivity following a 10-minute pulse) was increased by treatment with 10 nmol/L dexamethasone from 77 to 112 minutes, and the value for apoB-48 increased from 145 to 250 minutes. Treatment with 100 nmol/L dexamethasone also stimulated secretion of
35
S-labeled apoB-100 and apoB-48 by twofold and 1.5-fold, respectively. The increased secretion of apoB-100 and apoB-48 after dexamethasone treatment was confirmed by immunoblot analysis for apoB mass, and the effect was relatively specific since albumin secretion was not significantly changed. We conclude that glucocorticoids promote the secretion of hepatic apoB-containing lipoproteins by increasing the net synthesis of apoB-100 and apoB-48 and by decreasing the intracellular degradation of newly synthesized apoB. An increased action of glucocorticoids coupled with a decreased ability of insulin to suppress these effects in insulin resistance can lead to hyperapobetalipoproteinemia and an increased risk of atherosclerosis.
A Definition of Advanced Types of Atherosclerotic Lesions and a Histological Classification of Atherosclerosis
Authors: Stary Herbert C. , Chandler A. Bleakley , Dinsmore Robert E. , Fuster Valentin , Glagov Seymour , Insull William , Rosenfeld Michael E. , Schwartz Colin J. , Wagner William D. , Wissler Robert W.
Published: June 2011

Abstract
This report is the continuation of two earlier reports that defined human arterial intima and precursors of advanced atherosclerotic lesions in humans. This report describes the characteristic components and pathogenic mechanisms of the various advanced atherosclerotic lesions. These, with the earlier definitions of precursor lesions, led to the histological classification of human atherosclerotic lesions found in the second part of this report. The Committee on Vascular Lesions also attempted to correlate the appearance of lesions noted in clinical imaging studies with histological lesion types and corresponding clinical syndromes. In the histological classification, lesions are designated by Roman numerals, which indicate the usual sequence of lesion progression. The initial (type I) lesion contains enough atherogenic lipoprotein to elicit an increase in macrophages and formation of scattered macrophage foam cells. As in subsequent lesion types, the changes are more marked in locations of arteries with adaptive intimal thickening. (Adaptive thickenings, which are present at constant locations in everyone from birth, do not obstruct the lumen and represent adaptations to local mechanical forces). Type II lesions consist primarily of layers of macrophage foam cells and lipid-laden smooth muscle cells and include lesions grossly designated as fatty streaks. Type III is the intermediate stage between type II and type IV (
atheroma
, a lesion that is potentially symptom-producing). In addition to the lipid-laden cells of type II, type III lesions contain scattered collections of extracellular lipid droplets and particles that disrupt the coherence of some intimal smooth muscle cells. This extracellular lipid is the immediate precursor of the larger, confluent, and more disruptive core of extracellular lipid that characterizes type IV lesions. Beginning around the fourth decade of life, lesions that usually have a lipid core may also contain thick layers of fibrous connective tissue (type V lesion) and/or fissure, hematoma, and thrombus (type VI lesion). Some type V lesions are largely calcified (type Vb), and some consist mainly of fibrous connective tissue and little or no accumulated lipid or calcium (type Vc).
Plasma Lipoprotein(a) Levels in Subjects Attending a Metabolic Ward
Authors: Margaglione Maurizio , DiMinno Giovanni , Grandone Elvira , Celentano Egidio , Vecchione Gennaro , Cappucci Giuseppe , Grilli Massimo , Mancini Francesco Paolo , Postiglione Alfredo , Panico Salvatore , Mancini Mario
Published: June 2011

Abstract
In this cross-sectional study we compared the abilities of lipoprotein(a) [Lp(a)], plasminogen activator inhibitor–1 (PAI-1), and tissue plasminogen activator (TPA) to discriminate between individuals with and without a history of stroke from among subjects in a metabolic ward. A total of 210 subjects (108 men and 102 women; mean age, 63.8 years; range, 31 to 86 years) provided plasma and DNA samples for the study. Of these, 51 men and 50 women had a history of ischemic stroke. The 109 subjects without a history of stroke were compared with those with such a history for major risk factors for ischemic events. Mean plasma TPA and PAI-1 levels significantly (
P
<.001) discriminated among subjects younger than 70 years with a history of stroke. The mean plasma Lp(a) level of stroke subjects (21.9 mg/dL) did not differ significantly from that of control subjects (15.2 mg/dL). However, among individuals <70 years old, Lp(a) plasma levels >50 mg/dL were more common among stroke patients (8 with versus 1 without,
P
<.01 by χ
2
test). A molecular variation in the 5′ flanking region of the apo(a) gene that has been related to elevated Lp(a) plasma levels (G/A-914) was not strongly correlated with circulating levels of Lp(a), nor did Lp(a) levels correlate with a polymorphism of the apo(a) gene (G/A-21), which is strongly linked (
P
<.001) to the G/A-914 variation. In this setting, the relation between Lp(a) and cerebral ischemia appears to be limited to individuals below 70 years with elevated (>50 mg/dL) plasma levels of the lipoprotein.
Effects of Simvastatin on Plasma Lipids and Apolipoproteins in Familial Hypercholesterolemic Swine
Authors: Hasler-Rapacz Judith , Kempen Herman J. , Princen Hans M.G. , Kudchodkar Bhalchandra J. , Lacko Andras , Rapacz Jan
Published: June 2011

Abstract
Familial hypercholesterolemia (FHC) in swine, which resembles human familial combined hyperlipidemia, is a complex lipid and lipoprotein disorder associated with the development of severe coronary lesions similar to those occurring in advanced human coronary disease. The disorder is characterized by elevated plasma total cholesterol (TC), triglycerides (TG), LDL-cholesterol (LDL-C), apolipoproteins (apo) B, C-III, and E, and by decreased levels of HDL-cholesterol (HDL-C), apoA-I, and lecithin:cholesterol acyltransferase (LCAT) activity. A dose-response study with simvastatin, a specific inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, was conducted in four treatment groups of FHC animals, exhibiting TC≥250 mg/dL. The animals were fed 0, 80, 200, or 400 mg simvastatin daily for 3 weeks. The measured serum parameters included the levels of TC, VLDL-C, LDL-C, HDL-C, TG, lathosterol, apoA-I, B, C-III, and E, as well as LCAT activity. Simvastatin at 200 mg/d significantly decreased the levels of TC (−25%), LDL-C (−27%), lathosterol (−40%), apoB (−22%), apoC-III (−37%), and apoE (−24%) and modestly decreased the levels of HDL-C (−12%) and apoA-I (−11%) (percent relative to the average pretreatment and posttreatment baseline values) but did not affect the levels of TG, VLDL-C, the lathosterol/TC ratio, or LCAT activity. The levels of TC, LDL-C, apoB, and E were also lowered by simvastatin at 80 or 400 mg/d, but to a lesser extent than at 200 mg/d, while the other parameters were not influenced at these doses. The simvastatin-induced decreases of LDL-C, HDL-C, and apoA-I, B, C-III, and E were significantly correlated among each other. These results show that the trend of responses in TC, LDL-C, apoB, apoC-III, and apoE to simvastatin in the FHC swine is similar to that observed in humans, although the drug is less potent and efficacious in swine, while the results are different from those in humans with regard to the remaining parameters.
Association Between Serum Fibrinogen Concentrations and HDL and LDL Subfraction Phenotypes in Healthy Men
Authors: Halle Martin , Berg Aloys , Keul Joseph , Baumstark Manfred W.
Published: June 2011

Abstract
Hyperfibrinogenemia and a dyslipoproteinemia characterized by reduced HDL
2
cholesterol and elevated levels of small, dense LDL particles are risk factors for coronary artery disease. However, the relationship between fibrinogen and lipoproteins, in particular LDL subfractions, is uncertain. We therefore measured serum fibrinogen levels and serum concentrations of cholesterol and apolipoproteins of VLDL, IDL, six LDL, and two HDL subfractions by using the technique of density-gradient ultracentrifugation in 132 nonsmoking men without evidence of coronary artery disease or infection. Dividing the individuals into quartiles according to their fibrinogen values showed that men within the highest fibrinogen quartile (fibrinogen 2.90 to 4.34 g/L) had significantly higher concentrations of small, dense LDL (
d
>1.044 g/mL) apolipoprotein B and cholesterol and lower concentrations of HDL
2
cholesterol than men within the lower fibrinogen quartiles (fibrinogen <2.55 g/L). Multivariate regression analysis revealed that the association between fibrinogen and small, dense LDL particles was independent of serum triglycerides, cholesterol, body mass index, and age. In contrast, the relationship between fibrinogen and HDL
2
cholesterol was primarily influenced by triglycerides and cholesterol and not independently influenced by fibrinogen. There were no significant differences between the quartiles in terms of insulin, glucose, insulin resistance, free fatty acids, lipoprotein(a), and blood pressure. This study showed that fibrinogen is associated with the expression of a more atherogenic LDL subfraction phenotype independent of body mass index, age, other serum lipids, and insulin resistance in a healthy male nonsmoking population. The reason for this association is uncertain. These findings reinforce the evidence that fibrinogen should be determined when assessing coronary risk.
Levels of Factor VIIc Associated With Decreased Tissue Factor Pathway Inhibitor and Increased Plasminogen Activator Inhibitor-1 in Dyslipidemias
Authors: Zitoun Danièle , Bara Lucienne , Basdevant Arnaud , Samama Meyer Michel
Published: June 2011

Abstract
Tissue factor pathway inhibitor (TFPI), a kunitz-type inhibitor of the extrinsic coagulation pathway, factor VII coagulant (FVIIc), FVIIa, and the fibrinolytic factors plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (TPA) have been studied in various hyperlipidemias. Compared with a normal lipidic group, mean TFPI activity was 70% higher (
P
<.001) and 36% higher (
P
<.001) in type IIa and IIb hyperlipidemias, respectively, and was lower by 13% in type IV hyperlipidemia (
P
=.05). TFPI was correlated with LDL cholesterol (
P
<.001), total cholesterol (
P
<.001), HDL cholesterol (
P
<.01), apolipoproteins (apo) AI (
P
<.001) and B (
P
<.001) and lipoprotein a (
P
<.01). TFPI was negatively correlated with the triglyceride level (
P
<.05); the correlation was dependent on LDL cholesterol and HDL cholesterol levels, which were decreased in type IV hyperlipidemia. FVIIc activity (
P
<.001) was increased by 30% in both type IV and type IIb hyperlipidemia and was correlated with triglyceride levels. FVIIa was not significantly increased in any group compared with control group. FVIIc was correlated with triglyceride level (
P
<.001), while FVIIa was not. Interestingly, FVIIa was correlated with FVIIc (
r
=.5,
P
<.001) in the control group as well as in the hyperlipidemic groups (
r
=.32,
P
<.01). These results favor the hypothesis that higher FVIIc concentrations in hyperlipidemic patients are likely due to enhancement of synthesis of FVII and that a part of this FVII circulates in an activated chemical form. Compared with the control group, PAI-1 activity was twofold higher (
P
<.08) in type IIa hyperlipidemia, threefold higher (
P
<.001) in type IIb hyperlipidemia, and fourfold higher in type IV hyperlipidemia (
P
<.001). PAI-1 activity correlated with triglyceride levels (
P
<.001), apoB levels (
P
<.001) and total cholesterol levels (
P
<.05). These correlations were dependent on apoB and probably reflect the correlation between PAI-1 and VLDL. In contrast, TPA level was normal in the different hyperlipidemias. No correlation was found between TFPI, FVIIc, and PAI-1. Variation of TFPI activity appears to be related to the variations of its main lipoprotein carriers: LDL, HDL, and Lp (a). The association in hypertriglycemic patients of hypercoagulability (increased FVIIc and decreased TFPI) and hypofibrinolysis (increased PAI-1) may explain thrombosis predisposition of some of these patients. However, it would be interesting to study the increased levels of endothelium-derived TFPI in plasma induced by the injection of heparin.
Paraoxonase Genotypes, Lipoprotein Lipase Activity, and HDL
Authors: Nevin David N. , Zambon Alberto , Furlong Clement E. , Richter Rebecca J. , Humbert Richard , Hokanson John E. , Brunzell John D.
Published: June 2011

Paraoxonase, an enzyme associated with the high density lipoprotein (HDL) particle, hydrolyzes paraoxon, the active metabolite of the insecticide parathion. Several studies have shown that paraoxonase levels in humans have a distribution characteristic of two alleles, one with low activity and the other with high activity. Paraoxonase also has arylesterase activity, which does not exhibit activity polymorphism and can therefore serve as an estimate of enzyme protein. Although the ability of paraoxon to irreversibly inhibit lipoprotein lipase (LPL) has been exploited experimentally for many years, the role of plasma paraoxonase in lipoprotein metabolism is unknown. Seventy-two normal individuals were examined for paraoxonase genotypes, plasma paraoxonase and arylesterase activities, postheparin LPL and hepatic lipase (HL) activities, and lipoprotein levels to determine whether (1) paraoxonase activity or genotype determines lipoprotein levels via an effect on LPL or HL activity or (2) variation in LPL and HL activities determines HDL levels and indirectly affects paraoxonase activity and protein levels in plasma. In the entire group, paraoxonase activity was related to arylesterase activity and genotype. Whereas arylesterase activity was correlated with HDL cholesterol (HDL-C) and apolipoproteinA-I (apoA-I) levels, neither arylesterase nor paraoxonase was correlated with LPL or HL activity. Furthermore, LPL activity was positively correlated and HL inversely correlated with HDL cholesterol and apoA-I levels, whereas LPL was inversely correlated with triglyceride levels. The paraoxonase genotypes of the study group were 30 individuals homozygous for the low-activity allele, 38 heterozygotes, and 4 individuals homozygous for the high-activity allele. Paraoxonase genotype accounted for ≈.75 of the variation in paraoxonase activity. Paraoxonase activity was linearly related to arylesterase activity within each subgroup. No difference in either LPL or HL activity was seen as a function of paraoxonase genotype, nor were differences seen in plasma triglyceride or HDL-C by genotype by ANOVA. The relation between LPL and HL and components of HDL in the paraoxonase genotypic subgroups in general reflected the associations seen in the group as a whole. Multivariate analysis showed that LPL, HL, and arylesterase, a measure of paraoxonase mass, were independent predictors of HDL cholesterol, while paraoxonase genotype or activity was not. Thus, variation in LPL and HL appears to be significantly related to HDL cholesterol and apoA-I levels. The levels of HDL are a major correlate of paraoxonase protein levels, while paraoxonase genotype is the major predictor of plasma paraoxonase activity.
Role of NO in Flow-Induced Remodeling of the Rabbit Common Carotid Artery
Authors: Tronc François , Wassef Michel , Esposito Bruno , Henrion Daniel , Glagov Seymour , Tedgui Alain
Published: June 2011

Flow-induced changes in vessel caliber tend to restore baseline wall shear stress (WSS) and have been reported to be endothelium-dependent. To investigate the role of endothelium-derived nitric oxide (NO) in the adaptive increase in artery diameter in response to a chronic increase in blood flow, an arteriovenous fistula was constructed between the left common carotid artery (CCA) and the external jugular vein in 22 New Zealand White rabbits, and NO synthesis was inhibited in 14 animals by long-term administration of
N
G
-nitro-
l
-arginine-methyl ester (L-NAME) in drinking water given for 4 weeks. The remaining 8 animals served as controls. Mean arterial blood pressure was not significantly altered by L-NAME treatment (91±2 in control versus 98±3 mm Hg in L-NAME–treated rabbits). Blood flow significantly increased in the left CCA in both groups but was lower in L-NAME–treated than control animals (106.1±10.7 versus 196.2±32.3 mL/min,
P
<.003). The diameter of the flow-loaded left CCA also increased significantly in both groups compared with the right CCA (2.15±0.12 and 2.54±0.1 mm, respectively,
P
<.02), but the increase was less in the L-NAME–treated than the control group (3.24±0.09 and 4.64±0.17 mm, respectively,
P
<.0001). The diameter of the anastomosed veins was also increased but to a much lesser degree in L-NAME–treated animals than in controls (4.14±0.29 versus 7.94±0.51 mm,
P
<.0001). As a result of artery enlargement, WSS was normalized in the flow-loaded left CCA of the control group (8.87±0.77 dynes/cm
2
) regardless of blood flow values. In L-NAME–treated animals, however, WSS was only partially regulated, the mean value being significantly increased (18.7±2.2 dynes/cm
2
,
P
<.006). Moreover, a highly significant positive correlation between WSS and blood flow was obtained in L-NAME–treated animals (
r
=.84,
P
<.0001). We also found remodeling of the artery wall, with a larger increase in the medial cross-sectional area associated with an increased number of smooth muscle cells, in the control group compared with the L-NAME–treated group (0.75±0.09 versus 0.49±0.04 mm
2
and 4504±722 versus 2717±282 cells/mm
2
,
P
<.03). We conclude that NO plays a role in the increase of vessel caliber in response to chronic increase in blood flow. As yet unidentified additional metabolic processes appear to be necessary for a complete regulatory response.
Monocyte Recruitment and Neointimal Hyperplasia in Rabbits
Authors: Rogers Campbell , Welt Frederick G.P. , Karnovsky Morris J. , Edelman Elazer R.
Published: June 2011

Among the many effects of heparin independent of its effects on coagulation are inhibition of vascular smooth muscle cell proliferation and regulation of leukocyte–blood vessel interactions. The potential link between these effects was examined in an animal model of vascular injury rich in inflammatory cells: the placement of endovascular metal stents in rabbit iliac arteries. Monocyte adhesion stimulated by early focal thrombus was maximal after 3 days, with infiltrating monocytes and intimal cell proliferation maximal after 7 days. Tissue monocyte number dictated cell proliferation at each time point (R2=.92,P<.0001). Heparin reduced both early monocyte adhesion as well as monocyte infiltration within the neointima 7 and 14 days after stent placement. Reductions in adherent and tissue monocytes were commensurate with reductions in intimal cell proliferation and intimal thickening. At 14 days, heparin's inhibition of mononuclear cell adhesion was correlated with its suppression of intimal thickening (R2=.82,P<.0001). Monocytes have been hypothesized to serve as markers, initiators, and promoters of arterial occlusive diseases. Heparin's ability to inhibit mononuclear cell adhesion and penetration and reduce neointimal size and cell proliferation after vascular injury may further implicate monocytes in the pathogenesis of neointimal hyperplasia after mechanical arterial injury.
Hypercoagulable State in Patients With Antiphospholipid Syndrome Is Related to High Induced Tissue Factor Expression on Monocytes and to Low Free Protein S
Authors: Reverter Joan-Carles , Tàssies Dolors , Font Josep , Monteagudo Joan , Escolar Ginés , Ingelmo Miguel , Ordinas Antoni
Published: June 2011

Antiphospholipid antibodies (aPLs) are associated with thrombosis, but the mechanisms of this thrombotic tendency are unknown. We studied 56 patients (12 with systemic lupus erythematosus [SLE] and aPLs and previous thrombosis, 12 with SLE and aPLs but no thrombosis, 15 with SLE without aPLs or thrombosis, 11 with primary antiphospholipid syndrome with thrombosis, and 6 asymptomatic subjects with aPLs) to investigate the ability of aPLs to induce tissue factor (TF) expression on human normal monocytes. A double direct immunofluorescence technique (anti-CD14 and anti-TF) was used, and procoagulant activity in viable and disrupted cells was measured after plasma incubation for 6 hours at 37°C with normal mononuclear cells. Hemostasis regulatory proteins, prothrombin fragment 1+2, and thrombin–antithrombin III complex levels were determined. Increased TF expression and procoagulant activity were observed using plasma samples from SLE patients with aPLs and thrombosis (P<.01) and from primary antiphospholipid syndrome patients (P<.01) but not from patients with SLE and aPLs but no thrombosis, patients with SLE without aPLs, or asymptomatic patients with aPLs. Purified aPL immunoglobulins from one primary antiphospholipid syndrome and two SLE patients added to normal plasma showed a significant increase in both TF expression and procoagulant activity (P<.05) compared with purified aPL from two SLE patients without thrombosis. The addition of nonspecific IgG from three SLE patients without aPLs and from three control subjects did not increase TF expression. Low free protein S was seen in eight patients. Increased TF expression and low free protein S correlated with thrombosis (P<.01) and with higher prothrombin fragment 1+2 and thrombin–antithrombin III values (P<.01). These observations may contribute to a further understanding of the thrombotic risk in aPL patients.
Coronary Artery Restenosis After Balloon Angioplasty in Humans Is Associated With Circumferential Coronary Constriction
Authors: Luo Huai , Nishioka Toshihiko , Eigler Neal L. , Forrester James S. , Fishbein Michael C. , Berglund Hans , Siegel Robert J.
Published: June 2011

Therapies that inhibit intimal hyperplasia do not prevent restenosis after coronary artery balloon angioplasty, suggesting that additional mechanisms may be responsible for restenosis in humans. Using an intravascular ultrasound (Hewlett-Packard Sonos Intravascular Imaging System), 3.5F, 30-MHz (Boston Scientific) monorail imaging catheter, we studied 17 patients with clinical and angiographic restenosis at an average (mean±SD) of 7±6 months after balloon angioplasty (13 men: age, 71±10 years; 12 left anterior descending coronary arteries, 4 right coronary arteries, and 1 left circumflex coronary artery). The lumen area (LA), vessel wall area (VWA), and total cross-sectional area (CSA) within the external elastic lamina were measured at the restenosis site and at proximal and distal reference sites, which were defined as adjacent segments with the least amount of plaque. Consistent with coronary angiography findings, decreased LA at the restenotic site was detected in all 17 patients. The unique finding was that total CSA at the restenotic site was significantly decreased compared with both proximal and distal reference sites (10.1±2.4 versus 14.8±3.2 mm
2
and 10.1±2.4 versus 13.8±3.1 mm
2
, respectively,
P
<.001), whereas VWA (intima plus media) was slightly increased at the angioplasty site compared with both proximal and distal reference sites (8.0±2.3 versus 7.6±2.3 mm
2
and 8.0±2.3 versus 6.7±2.3 mm
2
, respectively,
P
=NS). Eighty-three percent of the loss in LA at the restenotic site was due to constriction of the total CSA, while the increase in VWA at the restenotic site accounted for only a 17% loss in LA. We then compared these results with the morphology of coronary artery segments in 14 patients without restenosis. These coronary artery segments had been previously treated with balloon angioplasty (7±5 months). Unlike that in restenotic lesions, the total CSA within the external elastic lamina at the sites of previous angioplasty was similar to that in distal and proximal reference sites (
P
=NS). Significant and consistent reduction in arterial CSA, with a minor increase in VWA, characterizes human coronary lesions that cause angiographic restenosis. These data suggest that in humans, “recoil” and/or vascular contraction with healing in response to balloon injury is a major contributor to restenosis after balloon angioplasty.
Expression of VEGF Receptors in Arteries After Endothelial Injury and Lack of Increased Endothelial Regrowth in Response to VEGF
Authors: Lindner Volkhard , Reidy Michael A.
Published: June 2011

Vascular endothelial growth factor (VEGF) is an endothelial cell–specific factor with angiogenic effects in vivo and mitogenic effects in vitro. Administration of VEGF has been reported to stimulate endothelial growth in denuded arteries and new blood vessel formation in models of induced tissue ischemia. In the present study, expression of VEGF and its receptors
flk-1
and
flt-1
was determined in injured aortas and carotid arteries of rats and mice. Neither VEGF nor
flk-1
mRNA was detectable in vascular cells. mRNA levels for
flt-1
were dramatically upregulated at the leading edge of a growing endothelial monolayer in vivo; however, these cells did not demonstrate increased replication after VEGF infusion. Furthermore, all doses and treatment protocols of VEGF failed to promote reendothelialization in denuded arteries. At sites of
flt-1
expression, VEGF increased permeability. These areas revealed a loss of endothelial contacts at the ultrastructural level. These findings suggest that VEGF is not a direct mitogen for large-vessel endothelium in vivo and that VEGF may play a role in abolishing contact inhibition, which may be a prerequisite for endothelial proliferation.
Relationship of Plasma Cholesteryl Ester Transfer Protein to HDL Cholesterol
Authors: Föger Bernhard , Ritsch Andreas , Doblinger Alfred , Wessels Holger , Patsch Josef R.
Published: June 2011

To evaluate the independent effect of cholesteryl ester transfer protein (CETP) on HDL concentrations in humans, we measured lipids, lipoproteins, postprandial lipemia after an oral fat load, CETP mass, and the activities of CETP, lipoprotein lipase (LPL), and hepatic lipase in 16 healthy, normotriglyceridemic men and in 23 men with moderate, primary hypertriglyceridemia on an American Heart Association Step I diet. Fasting triglycerides and postprandial lipemia were increased and HDL cholesterol (HDL-C) was decreased in hypertriglyceridemic men compared with control subjects (
P
<.001). In the normotriglyceridemic group, CETP mass (
P
<.001) and activity (
P
<.005) were directly related to LPL activity After statistical adjustment for this close association, no significant relationship of CETP to HDL-C independent of LPL activity could be demonstrated in the normotriglyceridemic subjects. In contrast, CETP was unrelated to LPL activity in the hypertriglyceridemic subjects, but CETP concentrations showed a close inverse relationship to HDL-C (
r
=−.504,
P
=.014). Structural equation modeling of the association structures between HDL and fasting and postprandial triglycerides, endothelial lipases, and CETP in both groups indicated that the overall regression models for the two groups differed (
P
<.05). Specifically, the associations between CETP mass and activity and HDL-C differed between both groups (both
P
<.01). We conclude that high-normal CETP levels lower HDL-C in nonsmoking, nonobese men with moderate, primary hypertriglyceridemia on a hypolipidemic diet, but not in healthy, normotriglyceridemic men on an unrestricted diet. Thus, variation in CETP plasma concentrations may contribute to the high-triglyceride, low-HDL phenotype.
Peripheral Blood Mononuclear Phagocyte Subpopulations as Cellular Markers in Hypercholesterolemia
Authors: Rothe Gregor , Gabriel Holger , Kovacs Eva , Klucken Jochen , Stöhr Josef , Kindermann Wilfried , Schmitz Gerd
Published: June 2011

Mononuclear phagocytes play a major role in the development of vascular lesions in atherogenesis. The goal of our study was to characterize circulating blood monocyte subpopulations as potential cellular markers of systemic immunological abnormalities in hypercholesterolemia. In normal subjects, three-parameter immunophenotyping of whole blood revealed that 61.3±6.0% of monocytes showed “bright” expression of the lipopolysaccharide receptor (LPSR: CD14) and Fcγ receptor I (RI: CD64) without expression of Fcγ-RIII (CD16). Other monocyte subsets (populations 2, 3, 4, and 5) were characterized by the simultaneous expression of both Fcγ-R's (25.6±5.0%), isolated expression of Fcγ-RIII (9.4±1.7%), or high expression of CD33 (3.7±1.1%) with only dim expression of CD14, respectively. The smallest subset of monocytes (population 5: 2.1±0.8%) differed from the predominant population of CD14brightCD64+CD16−monocytes by additional expression of neural cell adhesion molecule (N-CAM: CD56). In a group of hypercholesterolemic patients (n=19), high density lipoprotein cholesterol levels were negatively correlated to the population size of CD64−CD16+monocytes. In both healthy subjects (n=55) and hypercholesterolemic patients, the rare apolipoprotein E3/E4 and E4/E4 phenotypes were associated with a tendency toward a larger population of CD64−CD16+monocytes. Expression of the variant activation antigen CD45RA by peripheral blood mononuclear phagocytes showed a positive correlation to plasma levels of the atherogenic lipoproteins low density lipoprotein and lipoprotein(a). These data suggest that systemic abnormalities in mononuclear phagocyte subpopulations may play a role in the pathogenesis of atherosclerosis.
Effect of Antioxidants Alone and in Combination With Monounsaturated Fatty Acid–Enriched Diets on Lipoprotein Oxidation
Authors: Reaven Peter , Grasse Barbara , Barnett Joellen
Published: June 2011

Previous studies have demonstrated that compared with more buoyant LDL, dense LDL (D-LDL) is more susceptible to oxidation and less readily protected from oxidation by antioxidant enrichment. However, diets enriched in monounsaturated fatty acids (MUFAs) appear particularly effective in protecting D-LDL from oxidation. We therefore evaluated in 12 non–insulin-dependent diabetes mellitus subjects the effects of supplementation with α-tocopherol (1600 IU/d) and probucol (1 g/d) alone and in combination with an MUFA-enriched diet on LDL and LDL subfraction susceptibility to oxidation and monocyte release of superoxide anion. Subjects received either α-tocopherol or probucol for 4 months, and during the fourth month both groups also received an MUFA-enriched diet. α-Tocopherol levels were significantly increased in LDL and LDL subfractions (P<.05) after 3 months of supplementation. MUFA-enriched diets led to further increases in α-tocopherol in LDL fractions in the α-tocopherol group as well as in those receiving probucol. In the α-tocopherol–supplemented group, lag times were increased significantly (1.6- to 2.0-fold) for all LDL fractions, although the absolute increase was least for D-LDL. Although probucol supplementation increased lag times of LDL and LDL subfractions three- to fourfold, D-LDL was still more readily oxidized. In both the α-tocopherol– and probucol-supplemented groups the benefit of adding MUFA-enriched diets was greatest for D-LDL, with further increases in lag time of 26% and 18%, respectively. Neither antioxidant supplementation nor the addition of an MUFA-enriched diet reduced unstimulated or phorbol ester–stimulated monocyte superoxide anion production. These data demonstrate the markedly different effects that antioxidants and diet may have on different LDL subfractions, which may be particularly important in individuals with non–insulin-dependent diabetes mellitus, who frequently have increased amounts of D-LDL.
Impact of Body Mass Index on Coronary Heart Disease Risk Factors in Men and Women
Authors: Lamon-Fava Stefania , Wilson Peter W.F. , Schaefer Ernst J.
Published: June 2011

Increased body weight has been associated with an increased risk of morbidity and mortality from coronary heart disease (CHD) in several populations. We studied the distribution of body mass index (BMI, kg/m
2
) in men (n=1566; mean age, 49±10 years) and women (n=1627; mean age, 49±10 years) participating in the third examination cycle of the Framingham Offspring Study and the association of BMI with known CHD risk factors. In men, BMI increased with age until age 50 years, when it reached a plateau. In women, there was a trend toward an increase in BMI with age up to the seventh decade of life. Seventy-two percent of men and 42% of women had a BMI ≥25.00, the cutoff point for the definition of overweight. In age-adjusted analyses, BMI was significantly and linearly associated with systolic blood pressure, fasting glucose levels, plasma total cholesterol, VLDL cholesterol, and LDL cholesterol levels and was inversely and linearly associated with HDL cholesterol levels (
P
<.001) in nonsmoking men and women. The association between BMI and apolipoprotein B and A-I was similar to that of LDL and HDL cholesterol, respectively. LDL size was also linearly associated with BMI: subjects with higher BMI had smaller LDL particles. Lipoprotein(a) levels were not associated with BMI in this population. Of all these risk factors for CHD, reduced HDL cholesterol levels and hypertension were those more strongly associated with higher BMI in both men and women. Elevated triglyceride levels and small LDL particles, and diabetes in women, were also strongly associated with higher BMI values in this population. Our results indicate that a high prevalence of adult Americans are overweight and support the concept that increased BMI is associated with an adverse effect on all major CHD risk factors. These results emphasize the importance of excess body fat as a public health issue.
Lipoprotein(a) in Stored Plasma Samples and the Ravages of Time
Authors: Kronenberg Florian , Trenkwalder Evi , Dieplinger Hans , Utermann Gerd
Published: June 2011

Prospective case-control studies investigating lipoprotein(a) [Lp(a)] as a risk factor for atherosclerosis have measured Lp(a) in samples stored frozen up to nearly 20 years. We therefore prospectively examined the influence of long-term plasma sample storage on measured values, depending on the molecular weight of apolipoprotein(a) [apo(a)] isoforms. Apo(a) phenotyping was performed in 310 plasma samples, and Lp(a) was measured after 3 and 28 months of storage at −80°C. The values of both measurements correlated significantly for both low- and high-molecular-weight apo(a) phenotypes (
r
=.97 and
r
=.98, respectively,
P
<.001). Nevertheless, we detected on average a small decrease of 4.83% from mean±SD (median) 21.24±23.54 (11.10) mg/dL to 20.02±21.72 (10.55) mg/dL, which was statistically significant (
P
<.001). The absolute and relative Lp(a) decrease over time became larger with a decreasing number of kringle IV repeats of apo(a) (
P
<.05), and Lp(a) decreased markedly more in subjects with low-molecular-weight compared with those with high-molecular-weight apo(a) isoforms (−3.26 versus −0.46 mg/dL,
P
<.05). More than 70% of the absolute Lp(a) decrease in the total sample was caused by samples with low-molecular-weight apo(a) isoforms, which represented only 27% of the sample. Low-molecular-weight apo(a) isoforms are reportedly more frequent in patients with atherothrombotic disease compared with control subjects. Measurement of Lp(a) in several-year-old frozen samples is therefore likely to result in a preferential decrease and false lower Lp(a) concentrations in patient groups compared with control groups. The negative results of some prospective studies with retrospective measurement of Lp(a) may be caused by such an artifact.