bluuebunny/crossref_metadata_2025 huggingface dataset:
Dyslipidemia and Vascular Dysfunction in Diabetic Pigs Fed an Atherogenic Diet
Authors: Dixon J. L. , Stoops J. D. , Parker J. L. , Laughlin M. H. , Weisman G. A. , Sturek M.
Published: June 2011

Abstract
—Diabetic patients typically have not only hyperglycemia but also dyslipidemia. Study of the pathogenic components of the diabetic milieu and mechanisms of accelerated atherosclerosis is hindered by inadequate animal models. A potentially suitable animal model for human diabetic dyslipidemia is the pig, because it carries a large fraction of total cholesterol in low-density lipoprotein (LDL), similar to humans. In this study, male Sinclair miniature pigs were made diabetic by destroying the insulin-producing cells of the pancreas with alloxan and then were fed a high fat and high cholesterol diet for comparison with pigs fed a nondiabetic high fat and high cholesterol diet and control pigs. Diabetic pigs exhibited hyperglycemia, but plasma urea nitrogen, creatinine, and transaminase levels were in the normal range, indicating no adverse effects on kidney and liver function. The lipoprotein profile in diabetic pigs was similar to that found in human diabetic patients and was characterized by hypertriglyceridemia (2.8-fold increase versus control and high fat–fed pigs) and a profound shift of cholesterol distribution into the LDL fraction (81%) versus the distribution in high fat–fed (64%) and control (57%) pigs. LDL particles were lipid-enriched and more heterogeneous in diabetic pigs. Apolipoprotein B was distributed among a much broader spectrum of LDL particles, and apolipoprotein E was partially redistributed from high-density lipoprotein to apolipoprotein B–containing lipoproteins in diabetic pigs. There was little change in apolipoprotein A-I distribution. Diabetic pigs showed several early signs of excess vascular disease. In diabetic pigs, 75% of the coronary artery segments showed contractile oscillations in response to prostaglandin F
2α
compared with 25% in high fat–fed pigs and 10% in control pigs. Endothelium-dependent relaxation of brachial arteries was nearly abolished in diabetic pigs but unchanged in high fat–fed versus control pigs. Carotid artery Sudan IV staining for fatty streaks was significantly increased only in diabetic pigs. This porcine model should provide insights into the etiology of human diabetic dyslipidemia and facilitate study of peripheral vascular and coronary artery disease in diabetic patients.
Studies of Adhesion-Dependent Platelet Activation
Authors: Siljander Pia , Lassila Riitta
Published: June 2011

Abstract
—The molecular differences between native-type collagen type I fibrils (NC) and their pepsinated monomers (PC) were used to uncover receptors involved in platelet-collagen interaction along the adhesion-activation axis. The platelet-depositing capacity of NC and PC under blood flow and their adhesive properties and respective morphologies, aggregation, procoagulant capacity, and tyrosine phosphorylation were compared under different cationic milieus, including or excluding the glycoprotein (GP) Ia/IIa. NC was consistently a more preferable and activating substrate than PC during flow (5 minutes) and in platelet aggregation. In PPACK-treated blood, both NC (3.3-fold) and PC (2.7-fold) increased platelet attachment on elevation of the shear rate from 500 to 1640 s
−1
, whereas in citrated blood, adhesion and thrombus growth on PC were negligible under the high shear rate, unlike on NC (1.9-fold increase). The complete lack of platelet deposition on PC in citrated blood could be overcome by restoring physiological Mg
2+
concentration, and in contrast to NC, platelets interacting with PC were highly dependent on Mg
2+
during adhesion, aggregation, and procoagulant response. Monoclonal antibody (mAb 131.7) against GP IV inhibited platelet deposition to NC in citrated blood (2 minutes) by 49%, which was not further increased by coincubation with mAb against GP Ia (6F1). These results stress the importance of GP Ia/IIa in shear-resistant platelet deposition on collagen monomers. In native fibers, however, the preserved quaternary structure with telopeptides activates additional platelet receptors capable of substituting GP Ia/IIa and GP IV.
Two Common, Functional Polymorphisms in the Promoter Region of the β-Fibrinogen Gene Contribute to Regulation of Plasma Fibrinogen Concentration
Authors: van ’t Hooft Ferdinand M. , von Bahr Sara J. F. , Silveira Angela , Iliadou Anastasia , Eriksson Per , Hamsten Anders
Published: June 2011

Abstract—Plasma fibrinogen is a major risk factor for coronary heart disease, stroke, and peripheral artery disease. There is evidence that genetic variation in the β-fibrinogen gene contributes to the rate of synthesis of fibrinogen, but the molecular mechanism underlying the genetic heritability of the plasma fibrinogen concentration is largely unknown. We evaluated the physiological roles of 5 common nucleotide substitutions in the promoter region of the β-fibrinogen gene at positions −148, −249, −455, −854, and −993 from the transcriptional start site. Electrophoretic mobility shift assays revealed distinct differences in the binding characteristics of nuclear proteins between wild-type and mutant fragments of both the −455G/A and −854G/A polymorphisms, whereas no clear differences were observed for the −148C/T, −249C/T, and −993C/T sites. Transfection studies in HepG2 cells showed increased basal rates of transcription for both the G-to-A substitution at position −455 (+50%,P<0.05) and the G-to-A substitution at −854 (+51%,P<0.05). Additional transfection studies using proximal promoter constructs confirmed that both the −455A and −854A alleles independently enhance the basal rate of transcription of the β-fibrinogen gene. The rare alleles of the nonrelated −455G/A and −854G/A polymorphisms were also associated with significantly increased plasma fibrinogen levels in healthy middle-aged men. Overall, the 2 polymorphisms together explained ≈11% of the variation in plasma fibrinogen concentration. It is concluded that the −455G/A and −854G/A polymorphisms of the β-fibrinogen gene are physiologically relevant mutations with a significant impact on the plasma fibrinogen concentration.
Expression of Markers of Platelet Activation and the Interpatient Variation in Response to Abciximab
Authors: Bihour Claude , Durrieu-Jaïs Catherine , Macchi Laurent , Poujol Christel , Coste Pierre , Besse Pierre , Nurden Paquita , Nurden Alan T.
Published: June 2011

Abstract
—Our study concerns the biological effects of abciximab (c7E3 Fab, ReoPro), a powerful new antiplatelet drug that blocks glycoprotein (GP) IIb-IIIa complexes. Samples were examined from 6 patients with coronary artery disease who received a bolus of abciximab followed by a 10-μg/min infusion for at least 18 hours before percutaneous transluminal coronary angioplasty. Inhibition of ADP-induced PA was maximal for 4 patients but partial (79% and 53%) for 2 others during the infusion. Flow cytometry performed with monoclonal antibodies (PAC-1, AP-6, and F26) specific for the “activated” GP IIb-IIIa complex revealed large decreases in the expression of activation markers on platelets during therapy, but these decreases were less marked when inhibition of ADP-induced PA was incomplete. Residual aggregation was seen for all patients during the infusion when TRAP 14-mer peptide or thrombin was the stimulus. Unblocked GP IIb-IIIa complexes were detected on thrombin-stimulated platelets from the patients by immunoelectron microscopy performed using the monoclonal antibody AP-2. Unblocked GP IIb-IIIa complexes were also detected by flow cytometry when platelets preincubated for 1 hour in vitro with abciximab under saturating conditions were (1) incubated with TRAP 14-mer or (2) permeabilized with Triton X-100. In confirming interpatient variation in the platelet response to a standard dose of abciximab, our results also show that an uninhibited internal pool of GP IIb-IIIa complexes may mediate a residual response to strong agonists.
Mass Concentration of Plasma Phospholipid Transfer Protein in Normolipidemic, Type IIa Hyperlipidemic, Type IIb Hyperlipidemic, and Non–Insulin-Dependent Diabetic Subjects as Measured by a Specific ELISA
Authors: Desrumaux Catherine , Athias Anne , Bessède Ginette , Vergès Bruno , Farnier Michel , Perségol Laurence , Gambert Philippe , Lagrost Laurent
Published: June 2011

Abstract
—Mean plasma phospholipid transfer protein (PLTP) concentrations were measured for the first time by using a competitive enzyme-linked immunosorbent assay. PLTP mass levels and phospholipid transfer activity values, which were significantly correlated among normolipidemic plasma samples (
r
=0.787,
P
<0.0001), did not differ between normolipidemic subjects (3.95±1.04 mg/L and 575±81 nmol · mL
−1
· h
−1
, respectively; n=30), type IIa hyperlipidemic patients (4.06±0.84 mg/L and 571±43 nmol · mL
−1
· h
−1
, respectively; n=36), and type IIb hyperlipidemic patients (3.90±0.79 mg/L and 575±48 nmol · mL
−1
· h
−1
, respectively; n=33). No significant correlations with plasma lipid parameters were observed among the various study groups. In contrast, plasma concentrations of the related cholesteryl ester transfer protein (CETP) were higher in type IIa and type IIb patients than in normolipidemic controls, and significant, positive correlations with total and low density lipoprotein cholesterol levels were noted. Interestingly, plasma PLTP mass concentration and plasma phospholipid transfer activity were significantly higher in patients with non–insulin-dependent diabetes mellitus (n=50) than in normolipidemic controls (6.76±1.93 versus 3.95±1.04 mg/L,
P
<0.0001; and 685±75 versus 575±81 nmol · mL
−1
· h
−1
,
P
<0.0001, respectively). In contrast, CETP levels did not differ significantly between the 2 groups. Among non–insulin-dependent diabetes mellitus patients, PLTP levels were positively correlated with fasting glycemia and glycohemoglobin levels (
r
=0.341,
P
=0.0220; and
r
=0.382,
P
=0.0097, respectively) but not with plasma lipid parameters. It is proposed that plasma PLTP mass levels are related to glucose metabolism rather than to lipid metabolism.
Study of the Prothrombin Gene 20201 GA Variant in FV:Q
506
Carriers in Relationship to the Presence or Absence of Juvenile Venous Thromboembolism
Authors: Ehrenforth S. , Prondsinski M. von Depka , Aygören-Pürsün E. , Nowak-Göttl U. , Scharrer I. , Ganser A.
Published: June 2011

Abstract
—The G20210A transition of the prothrombin gene has been identified as a common but probably mild hereditary risk factor for venous thromboembolism (VTE). However, the prothrombin gene variant might contribute to the penetrance of thromboembolic disease in many patients with other prothrombotic defects, such as the FV:R506Q mutation. In this investigation, the
A20210
allele was found in 9 of 450 healthy controls (2%). Among 89 asymptomatic FV:Q
506
carriers, 3 subjects were doubly affected (3.4%). In contrast, of 263 unrelated carriers of the FV:Q
506
mutant with a history of juvenile VTE, 30 also had the prothrombin gene G20210A variant (11.4%), including 25 of 220 patients who were heterozygous (11.4%) and 5 of 43 homozygous (11.6%) for FV:Q
506
. Thus, the
A20210
allele of the prothrombin gene is significantly overrepresented in symptomatic FV:Q
506
carriers compared with healthy controls (
P
<0.0001) and asymptomatic relatives carrying the FV mutant (
P
=0.02). Persons homozygous for the 20210A allele were not found. A statistically significant increase in the prevalence of more unusual sites of venous thrombosis at clinical onset was found in doubly affected patients (9 of 30; 30%) compared with patients without the prothrombin gene variant (26 of 233; 11.1%) (
P
=0.004). First VTE occurred spontaneously in 53.3% of all doubly affected patients (16 of 30) and in 28.3% of all simply affected patients (66 of 233) (
P
=0.005). Among patients with VTE preceded by circumstantial risk factors, the
A20210
allele was found in 7.7% (14 of 181). We conclude that the
A20210
allele of the prothrombin gene is frequently coinherited in symptomatic FV:Q
506
carriers and possibly influences age, site, and type of thrombotic onset manifestation in these patients.
Polymorphism of the Methionine Synthase Gene
Authors: Morita Hiroyuki , Kurihara Hiroki , Sugiyama Takao , Hamada Chikuma , Kurihara Yukiko , Shindo Takayuki , Oh-hashi Yoshio , Yazaki Yoshio
Published: June 2011

Abstract
—Methionine synthase and 5,10-methylenetetrahydrofolate reductase (MTHFR) sequentially catalyze the remethylation of homocysteine to methionine. A point mutation in the encoding region of the methionine synthase gene, which results in substitution of an aspartic acid for a glycine residue (
D
919
G
), has been identified in patients of the
cbl
G genetic complementation group; these patients exhibit significantly decreased methionine synthase activity. Nevertheless, the
D
919
G
mutation has also been reported to be common in the general population. In this study, we analyzed the distribution of methionine synthase
D
/
G
polymorphism in the Japanese population and examined the extent to which it is associated with altered homocysteine metabolism and late-onset vascular diseases. We studied 215 patients with coronary artery disease, 251 patients with histories of ischemic stroke, and 257 control subjects. The methionine synthase genotype was analyzed by polymerase chain reaction followed by
Hae
III digestion; allele frequencies for the
D
919
G
variant of the enzyme proved to be similar in all 3 subject groups (control subjects, 0.17; coronary artery disease patients, 0.17; and ischemic stroke patients, 0.19). Furthermore, in patients with ischemic stroke, plasma levels of homocyst(e)ine and folate were similar, irrespective of methionine synthase genotype. Thus, the methionine synthase
D
919
G
mutation was found to be common in the Japanese general population, and it appears unlikely that this polymorphism has a major effect on homocysteine metabolism and/or the onset of vascular diseases.
The
T
Allele of the Hepatic Lipase Promoter Variant C−480T Is Associated With Increased Fasting Lipids and HDL and Increased Preprandial and Postprandial LpCIII:B
Authors: Jansen Hans , Chu Grace , Ehnholm Christian , Dallongeville Jean , Nicaud Viviane , Talmud Philippa J.
Published: June 2011

Abstract
—The common C−480T transition in the hepatic lipase (HL) promoter has been shown to be associated with lower HL activity and increased high density lipoprotein (HDL) cholesterol. We examined the frequency and lipid associations of this HL polymorphism in 385 healthy, young (18- to 28-year-old) men whose fathers had had a premature myocardial infarction (designated cases) and 405 age-matched controls. These individuals were participants in the European Atherosclerosis Research Study II postprandial trial, who had been recruited from 11 European countries in 4 regions (the Baltic; United Kingdom; and central and southern Europe). Overall, the frequency of the
T
allele was 0.207 in controls and 0.244 in cases (
P
=0.08). The
T
allele was associated with higher fasting plasma total cholesterol (
P
<0.01), triglycerides (
P
<0.01), and HDL cholesterol (
P
<0.01). The strongest association was found with apolipoprotein (apo) A-I concentration, which was 10% higher in individuals homozygous for the
T
allele compared with those homozygous for the
C
allele (
P
<0.001). This polymorphism had no effect on the rise in plasma triglyceride levels after a fatty meal. However, before and after the fat load was ingested, levels of particles containing both apoC-III and apoB (LpC-III:B) were higher in carriers of the
T
allele, with homozygotes having 23% and 27% higher levels preprandially and postprandially, respectively, than those homozygous for the
C
allele (
P
<0.05). Thus, our results demonstrate that the C−480T polymorphism in the HL promoter is associated with alterations in plasma lipids and lipoproteins and the accumulation of atherogenic LpC-III:B particles.
Selectin Blockade Reduces Neutrophil Interaction With Platelets at the Site of Deep Arterial Injury by Angioplasty in Pigs
Authors: Merhi Yahye , Provost Patrick , Chauvet Patrick , Théorêt Jean-François , Phillips M. Laurie , Latour Jean-Gilles
Published: June 2011

Abstract—The adhesion of neutrophils to damaged arterial surfaces is increased in the presence of platelets by a mechanism implicating platelet P-selectin. Such interactions may enhance thrombus formation and the vascular response to injury. In this study, we investigated the effects of a selectin blocker (CY-1503), an analogue of sialyl Lewisx, on platelet and neutrophil interactions after arterial injury produced by angioplasty in pigs.51Cr-platelet deposition and111In-neutrophil adhesion were quantified on intact, mildly and deeply injured carotid arterial segments, produced by balloon dilation, in control (saline, n=8) and treated (CY-1503, 15 mg/kg IV, n=7) pigs. The hematological parameters, the aggregation of whole blood in response to adenosine diphosphate, and the activating clotting time, as well as the heart rate and mean arterial blood pressure, were similar among groups and were not influenced significantly by CY-1503. The level of platelet and neutrophil adhesion increased significantly with the severity of arterial injury but was not influenced by CY-1503 on intact and mildly injured arterial segments. However, at the site of deep arterial injury, CY-1503 treatment was associated with a 58% reduction (P<0.01) in neutrophil adhesion, from 446.7±72.6×103neutrophils/cm2in the control group to 186.8±38.7×103neutrophils/cm2in the CY-1503–treated group, whereas platelet deposition remained unchanged (43.4±15.6×106platelets/cm2versus 50.1±12.2×106platelets/cm2in the control group). In in vitro adhesion experiments, using isolated platelet and neutrophil suspensions, we found that CY-1503 interfered with the adhesion of neutrophils to damaged arterial surfaces only in the presence of platelets. In contact with thrombogenic arterial surfaces, adherent and activated platelets supports neutrophil adhesion at the site of deep injury by an adhesive interaction involving neutrophil sialyl Lewisx. The inhibitory effect of CY-1503 on neutrophil interaction with adherent platelets may be clinically relevant in patients undergoing percutaneous transluminal coronary angioplasty where platelet and neutrophil interactions may enhance the acute and chronic arterial response to injury.
Relationship of Plasmin Generation to Cardiovascular Disease Risk Factors in Elderly Men and Women
Authors: Sakkinen Pamela A. , Cushman Mary , Psaty Bruce M. , Rodriguez Beatriz , Boineau Robin , Kuller Lewis H. , Tracy Russell P.
Published: June 2011

Abstract
—Plasmin–α2-antiplasmin complex (PAP) marks plasmin generation and fibrinolytic balance. We recently observed that elevated levels of PAP predict acute myocardial infarction in the elderly, yet little is known about the correlates of PAP. We measured PAP in 800 elderly subjects who were free of clinical cardiovascular disease in 2 cohort studies: the Cardiovascular Health Study and the Honolulu Heart Program. Median PAP levels did not differ between the Cardiovascular Health Study (6.05±1.46 nmol/L) and the Honolulu Heart Program (6.11±1.44 nmol/L), and correlates of PAP were similar in both cohorts. In CHS, PAP levels increased with age (
r
=0.30), procoagulant factors (eg, factor VIIc,
r
=0.15), thrombin activity (prothrombin fragment F1+2,
r
=0.29), and inflammation-sensitive proteins (eg, fibrinogen,
r
=0.44; factor VIIIc,
r
=0.37). PAP was associated with increased atherosclerosis as measured by the ankle-arm index (AAI) (
P
for trend, ≤0.001). PAP was negatively related to factors associated with the insulin resistance syndrome (IRS) (eg, fasting insulin,
r
=−0.26; body mass index,
r
=−0.26), possibly reflecting an association with plasminogen activator inhibitor-1 (
r
=−0.29). Although our study did not have sufficient power to detect a significant interaction, PAP and AAI appeared to be more weakly associated in subjects with more manifestations of the IRS: PAP appeared more strongly associated with AAI in the subgroup with 0 or 1 metabolic disorders (
P
≤0.001; slope estimate, −0.14) compared with the subgroup with 2 or more metabolic disorders (
P
=0.10; slope estimate, −0.08) and in those with non–insulin-dependent diabetes mellitus (
P
=0.46; slope estimate, −0.04). Although PAP reflects reactive fibrinolysis and is associated with subclinical atherosclerosis, this relationship may be weaker in populations with characteristics of the IRS, possibly reflecting the inhibitory effects of plasminogen activator inhibitor-1 on PAP. Decreased fibrinolysis in the presence of subclinical disease in subjects with hyperinsulinemia or glucose intolerance is consistent with the premise that depressed plasmin generation may enhance the progression of atherosclerosis in these people.
Intravenous Magnesium Reduces Infarct Size After Ischemia/Reperfusion Injury Combined with a Thrombogenic Lesion in the Left Anterior Descending Artery
Authors: Ravn Hanne B. , Moeldrup Ulla , Brookes Carl I. O. , Ilkjaer Lars B. , White Paul , Chew Michelle , Jensen Liselotte , Johnsen Soeren , Birk-Soerensen Lene , Hjortdal Vibeke E.
Published: June 2011

Abstract
—Experimental studies have demonstrated that intravenous magnesium (Mg) can protect the ischemic myocardium and has an antithrombotic effect. In patients with myocardial infarction, the reperfusion injury is complicated by the presence of a thrombogenic area in the affected coronary artery that may cause repetitive thrombus formation and embolization. We investigated the effect of Mg on infarct size in a randomized study in pigs. Myocardial infarction was induced by a 50-minute mechanical occlusion of the left anterior descending artery combined with an arterial injury, which stimulated a dynamic thrombus formation with emboli shedding on reperfusion. Magnesium sulfate (6 mmol/20 min plus 3 mmol/h) or saline was started at 30 minutes after coronary occlusion. Real-time ventricular pressure–volume loops were generated from the left ventricle by using a microtip pressure manometer and a conductance catheter. Platelet accumulation in the myocardium was evaluated by using
111
In-labeled platelets. After 4 hours of reperfusion, the infarct size/area at risk ratio in the placebo group was 46±0.06% (n=8) compared with 22±0.07% (n=6) in the Mg-treated animals (
P
=0.03). Ejection fraction decreased significantly in the control group but not in the Mg-treated animals (
P
=0.03). Platelet accumulation in the myocardium did not change significantly between the Mg- and placebo-treated animals (placebo group, 191±19%; Mg group, 177±29%; NS). The present study demonstrates that intravenous Mg infusion is able to reduce infarct size by >50% and preserve the ejection fraction in this model where ischemia/reperfusion injury was evaluated in the presence of a thrombogenic area in the nutrient artery.
Overexpression of Human Hepatic Lipase and ApoE in Transgenic Rabbits Attenuates Response to Dietary Cholesterol and Alters Lipoprotein Subclass Distributions
Authors: Barbagallo Carlo M. , Fan Jianglin , Blanche Patricia J. , Rizzo Manfredi , Taylor John M. , Krauss Ronald M.
Published: June 2011

Abstract
—The effect of the expression of human hepatic lipase (HL) or human apoE on plasma lipoproteins in transgenic rabbits in response to dietary cholesterol was compared with the response of nontransgenic control rabbits. Supplementation of a chow diet with 0.3% cholesterol and 3.0% soybean oil for 10 weeks resulted in markedly increased levels of plasma cholesterol and VLDL and IDL in control rabbits as expected. Expression of either HL or apoE reduced plasma cholesterol response by 75% and 60%, respectively. The HL transgenic rabbits had substantial reductions in medium and small VLDL and IDL fractions but not in larger VLDL. LDL levels were also reduced, with a shift from larger, more buoyant to smaller, denser particles. In contrast, apoE transgenic rabbits had a marked reduction in the levels of large VLDLs, with a selective accumulation of IDLs and large buoyant LDLs. Combined expression of apoE and HL led to dramatic reductions of total cholesterol (85% versus controls) and of total VLDL+IDL+LDL (87% versus controls). HDL subclasses were remodeled by the expression of either transgene and accompanied by a decrease in HDL cholesterol compared with controls. HL expression reduced all subclasses except for HDL
2b
and HDL
2a
, and expression of apoE reduced large HDL
1
and HDL
2b
. Extreme HDL reductions (92% versus controls) were observed in the combined HL+apoE transgenic rabbits. These results demonstrate that human HL and apoE have complementary and synergistic functions in plasma cholesterol and lipoprotein metabolism.
A Role for Changes in Platelet Production in the Cause of Acute Coronary Syndromes
Authors: van der Loo Bernd , Martin John F.
Published: June 2011

Abstract
—Platelets are heterogeneous with respect to their size, density, and reactivity. Large platelets are more active hemostatically, and platelet volume has been found to be increased both in patients with unstable angina and with myocardial infarction. Furthermore, platelet volume is a predictor of a further ischemic event and death when measured after myocardial infarction. Platelets which are anucleate cells with no DNA are derived from their precursor, the megakaryocyte. Therefore, it is suggested that changes in platelet size are determined at thrombopoiesis in the megakaryocyte and that those changes might precede acute cardiac events. Understanding of the signaling system that controls platelet production may also further elucidate the cascade of events leading to acute vascular occlusion in some patients.
Strong Induction of Members of the Chitinase Family of Proteins in Atherosclerosis
Authors: Boot Rolf G. , van Achterberg Tanja A. E. , van Aken Benien E. , Renkema G. Herma , Jacobs Michael J. H. M. , Aerts Johannes M. F. G. , de Vries Carlie J. M.
Published: June 2011

Abstract—Atherosclerosis is initiated by the infiltration of monocytes into the subendothelial space of the vessel wall and subsequent lipid accumulation of the activated macrophages. The molecular mechanisms involved in the anomalous behavior of macrophages in atherogenesis have only partially been disclosed. Chitotriosidase and human cartilage gp-39 (HC gp-39) are members of the chitinase family of proteins and are expressed in lipid-laden macrophages accumulated in various organs during Gaucher disease. In addition, as shown in this study, chitotriosidase and HC gp-39 can be induced with distinct kinetics in cultured macrophages. We investigated the expression of these chitinase-like genes in the human atherosclerotic vessel wall by in situ hybridizations on atherosclerotic specimens derived from femoral artery (4 specimens), aorta (4 specimens), iliac artery (3 specimens), carotid artery (4 specimens), and coronary artery (1 specimen), as well as 5 specimens derived from apparently normal vascular tissue. We show for the first time that chitotriosidase and HC gp-39 expression was strongly upregulated in distinct subsets of macrophages in the atherosclerotic plaque. The expression patterns of chitotriosidase and HC gp-39 were compared and shown to be different from the patterns observed for the extracellular matrix protein osteopontin and the macrophage marker tartrate-resistant acid phosphatase. Our data emphasize the remarkable phenotypic variation among macrophages present in the atherosclerotic lesion. Furthermore, chitotriosidase enzyme activity was shown to be elevated up to 55-fold in extracts of atherosclerotic tissue. Although a function for chitotriosidase and HC gp-39 has not been identified, we hypothesize a role in cell migration and tissue remodeling during atherogenesis.
Prostacyclin Synthase Gene Transfer Accelerates Reendothelialization and Inhibits Neointimal Formation in Rat Carotid Arteries After Balloon Injury
Authors: Numaguchi Yasushi , Naruse Keiji , Harada Mitsunori , Osanai Hiroyuki , Mokuno Shinji , Murase Kichiro , Matsui Hideo , Toki Yukio , Ito Takayuki , Okumura Kenji , Hayakawa Tetsuo
Published: June 2011

Abstract
—Prostacyclin (PGI
2
), a metabolite of arachidonic acid, has the vasoprotective effects of vasodilation, anti-platelet aggregation, and inhibition of smooth muscle cell proliferation. We hypothesized that an overexpression of endogenous PGI
2
may accelerate the recovery from endothelial damage and inhibit neointimal formation in the injured artery. To test this hypothesis, we investigated in vivo transfer of the PGI
2
synthase (PCS) gene into balloon-injured rat carotid arteries by a nonviral lipotransfection method. Seven days after transfection, a significant regeneration of endothelium was observed in the arteries transfected with a plasmid carrying the rat PCS gene (pCMV-PCS), but little regeneration was seen in those with the control plasmid carrying the
lacZ
gene (pCMV-lacZ) (percent luminal circumference lined by newly regenerated endothelium: 87.1±6.9% in pCMV-PCS-transfected vessels and 6.9±0.2% in pCMV-lacZ vessels,
P
<0.001). BrdU staining of arterial segments demonstrated a significantly lower incorporation in pCMV-PCS-transfected vessels (7.5±0.3% positive nuclei in vessel cells) than in pCMV-lacZ (50.7±9.6%,
P
<0.01). Moreover, 2 weeks after transfection, the PCS gene transfer resulted in a significant inhibition of neointimal formation (88% reduction in ratio of intima/media areas), whereas medial area was similar among the groups. Arterial segments transfected with pCMV-PCS produced significantly higher levels of 6-keto-PGF
1α
, the main metabolite of PGI
2
, compared with the segments transfected with pCMV-lacZ (10.2±0.55 and 2.1±0.32 ng/mg tissue for pCMV-PCS and pCMV-placZ,
P
<0.001). In conclusion, this study demonstrated that an in vivo PCS gene transfer increased the production of PGI
2
and markedly inhibited neointimal formation with accelerated reendothelialization in rat carotid arteries after balloon injury.
Cholesteryl Ester Hydroperoxide Lability Is a Key Feature of the Oxidative Susceptibility of Small, Dense LDL
Authors: Chancharme Laurent , Thérond Patrice , Nigon Fabienne , Lepage Sylvie , Couturier Martine , Chapman M. John
Published: June 2011

Abstract
—Abundant evidence has been provided to substantiate the elevated cardiovascular risk associated with small, dense, low density lipoprotein (LDL) particles. The diminished resistance of dense LDL to oxidative stress in both normolipidemic and dyslipidemic subjects is established; nonetheless, the molecular basis of this phenomenon remains indeterminate. We have defined the primary molecular targets of lipid hydroperoxide formation in light, intermediate, and dense subclasses of LDL after copper-mediated oxidation and have compared the relative stabilities of the hydroperoxide derivatives of phospholipids and cholesteryl esters (CEs) as a function of the time course of oxidation. LDL subclasses (LDL1 through LDL5) were isolated from normolipidemic plasma by isopycnic density gradient ultracentrifugation, and their content of polyunsaturated molecular species of phosphatidylcholine (PC) and CE and of lipophilic antioxidants was quantified by reverse-phase high-performance liquid chromatography. The molar ratio of the particle content of polyunsaturated CE and PC species containing linoleate or arachidonate relative to α-tocopherol or β-carotene did not differ significantly between LDL subspecies. Nonetheless, dense LDL contained significantly less polyunsaturated CE species (400 mol per particle) compared with LDL1 through LDL4 (range, ≈680 to 490 mol per particle). Although the formation of PC-derived hydroperoxides did not vary significantly between LDL subspecies as a function of the time course of copper-mediated oxidation, the abundance of the C18:2 and C20:4 CE hydroperoxides was uniquely deficient in dense LDL (23 and 0.6 mol per particle, respectively, in LDL5; 47 to 58 and 1.9 to 2.3 mol per particle, respectively, in other LDL subclasses) at propagation half-time. When expressed as a lability ratio (mol hydroperoxides formed relative to each 100 mol of substrate consumed) at half-time, the oxidative lability of CE hydroperoxides in dense LDL was significantly elevated (lability ratio <25:100) relative to that in lighter, larger LDL particle subclasses (lability ratio >40:100) throughout the oxidative time course. We conclude that the elevated lability of CE hydroperoxides in dense LDL underlies the diminished oxidative resistance of these particles. Moreover, this phenomenon appears to result not only from the significantly elevated PC to free cholesterol ratio (1.54:1) in dense LDL particles (1.15:1 to 1.25:1 for other LDL subclasses) but also from their unique structural features, including a distinct apoB100 conformation, which may facilitate covalent bond formation between oxidized CE and apoB100.
Antagonistic Effects of 17β-Estradiol, Progesterone, and Testosterone on Ca
2+
Entry Mechanisms of Coronary Vasoconstriction
Authors: Crews Janice K. , Khalil Raouf A.
Published: June 2011

Abstract
—The clinical observation that coronary artery disease is more common in men and postmenopausal women than in premenopausal women has suggested cardioprotective effects of female sex hormones including hormone-mediated coronary vasodilation. The purpose of this study was to investigate whether the sex hormone-induced coronary relaxation is caused by inhibition of Ca
2+
mobilization into coronary smooth muscle. The effects of 17β-estradiol, progesterone, and testosterone on vascular reactivity and
45
Ca
2+
influx were tested in deendothelialized coronary artery strips isolated from castrated male pigs. Prostaglandin F
2α
(PGF
2α
) (10
−5
mol/L) caused significant, maintained contraction of coronary artery strips. Caffeine (25 mmol/L), an activator of Ca
2+
release from intracellular stores, caused transient contraction in Ca
2+
-free solution whereas membrane depolarization by 96 mmol/L KCl, an activator of Ca
2+
entry, caused maintained contraction in the presence of external Ca
2+
. The 3 sex hormones caused significant and concentration-dependent relaxation of PGF
2α
- and 96 mmol/L KCl-induced contractions with 17β-estradiol being the most effective. The sex hormones did not significantly affect the transient caffeine contraction in Ca
2+
-free solution. In contrast, the sex hormones significantly inhibited the PGF
2α
- and KCl-induced
45
Ca
2+
influx. 17β-Estradiol caused similar inhibition of PGF
2α
- and KCl-induced contractions, suggesting inhibition of the same Ca
2+
entry mechanism. However, progesterone and testosterone caused greater relaxation of PGF
2α
-induced contraction than of KCl-induced contraction. We conclude that in coronary arteries of castrated male pigs, sex hormones inhibit Ca
2+
entry from extracellular space but not Ca
2+
release from intracellular stores. 17β-Estradiol mainly inhibits Ca
2+
entry, whereas progesterone and testosterone cause coronary relaxation by inhibiting other mechanisms in addition to Ca
2+
entry.
Niacin Accelerates Intracellular ApoB Degradation by Inhibiting Triacylglycerol Synthesis in Human Hepatoblastoma (HepG2) Cells
Authors: Jin Fu-You , Kamanna Vaijinath S. , Kashyap Moti L.
Published: June 2011

Abstract—The mechanism by which the potent drug niacin decreases apoB-containing atherogenic lipoproteins and prevents coronary disease is unclear. Utilizing human hepatoblastoma (HepG2) cells as an in vitro model, we have examined the effect of niacin on intracellular degradation of apoB and the regulatory mechanisms involved in apoB processing. Niacin significantly increased apoB degradation in a dose- and time-dependent manner. Treatment of HepG2 cells with calpain inhibitor I [N-acetyl-leucyl-leucyl-norleucinal (ALLN), an inhibitor of certain protease-mediated apoB degradation], did not alter niacin-induced apoB degradation. Niacin decreased inhibition of oleate-mediated apoB degradation. Niacin dose-dependently inhibited the synthesis of both fatty acids and triacylglycerol (TG) by 20% to 40% as determined by the incorporation of14C-acetate and3H-glycerol into fatty acids and TG, respectively. Incubation of HepG2 cells with niacin significantly inhibited (by 12% to 15%) fatty acid esterification to produce TG as assessed by the incorporation of3H-oleic acid into TG.14C-acetate incorporation into cholesterol and phospholipids was unchanged. The activity of microsomal triglyceride transfer protein (MTP), a carrier protein for lipids, was not altered by pretreatment of cells with niacin. ApoB mRNA expression and125I-LDL protein uptake were also unchanged. These data indicate that niacin accelerates hepatic intracellular post-translational degradation of apoB by selectively reducing triglyceride synthesis (through inhibiting both fatty acid synthesis and fatty acid esterification to produce TG) without affecting ALLN-inhibitable protease- or MTP-mediated intracellular apoB processing, resulting in decreased apoB secretion and hence lower circulating levels of the atherogenic lipoproteins.
Effect of Cardiopulmonary Bypass and Heparin on Plasma Levels of Lp(a) and Apo(a) Fragments
Authors: Mooser Vincent , Tinguely Francine , Fontana Pierre , Lenain Vincent , Vaglio Martine , Ruchat Patrick , von Segesser Ludwig K. , Marcovina Santica M. , Markert Michèle , Darioli Roger , Nicod Pascal
Published: June 2011

Abstract—Fragments of apolipoprotein(a) [apo(a)], the distinctive glycoprotein of lipoprotein(a) [Lp(a)], are present in human plasma and urine and have been implicated in the development of atherosclerosis. The mechanism responsible for the generation of apo(a) fragments in vivo is poorly understood. In this study, we examined the plasma levels of Lp(a) and apo(a) fragments [or free apo(a)] and urinary apo(a) in 15 subjects who underwent cardiac surgery necessitating cardiopulmonary bypass. We also measured the plasma concentration and activity of polymorphonuclear elastase, an Lp(a)-cleaving enzyme in vitro, and plasma levels of C-reactive protein. Despite a marked activation of polymorphonuclear cells and a pronounced inflammatory response, as documented by an 8-fold and a 35-fold increase in plasma levels of polymorphonuclear elastase and C-reactive protein, respectively, the proportion of plasma free apo(a) to Lp(a) and urinary excretion of apo(a) remained unchanged over a 7-day period after surgery, and polymorphonuclear elastase activity remained undetectable in plasma. No fragmentation of apo(a) was observed ex vivo in plasma samples collected before and after surgery. These data indicate that in this model, apo(a) is not fragmented in plasma and are consistent with the hypothesis that apo(a) fragments result from a constitutively active tissue mechanism that is not modified by cardiac surgery with cardiopulmonary bypass.
Prooxidant and Antioxidant Activities of Macrophages in Metal-Mediated LDL Oxidation
Authors: van Reyk David M. , Jessup Wendy , Dean Roger T.
Published: June 2011

Abstract—Murine macrophages incubated in metal-supplemented RPMI could block or promote oxidation of low-density lipoprotein (LDL) depending on the degree of metal supplementation. Only at high concentrations of Cu (1 μmol/L) and Fe (30 μmol/L) were cells prooxidant, leading to an accelerated rate of LDL oxidation over that measured in comparable cell-free media. At lower concentrations of Cu and Fe in RPMI, LDL oxidation in the presence of macrophages was inhibited relative to the cell-free condition. This appeared to be dependent on a stable modification of the culture medium, because preconditioning of media by incubation with macrophages could also decrease their capacity to sustain subsequent cell-free LDL oxidation. This was due, in part, to a removal of metal from the media during preconditioning. However, resupplementation of media with metals did not fully restore oxidative capacity, indicating that other cell-dependent antioxidant modifications occurred. This did not involve significant alterations to the thiol content of the media. This study highlights the complexity of the role that cells such as macrophages have with regards to LDL oxidation in vitro and demonstrate that there are both antioxidative and prooxidative components.
α-Tocopherol Decreases Interleukin-1β Release From Activated Human Monocytes by Inhibition of 5-Lipoxygenase
Authors: Devaraj Sridevi , Jialal Ishwarlal
Published: June 2011

Abstract—Cardiovascular disease is the leading cause of morbidity and mortality in westernized populations. Low levels of α-tocopherol (AT) are associated with increased incidence of atherosclerosis and increased intakes appear to be protective. Recently, we showed that supplementation with AT resulted in significant decreases in monocyte superoxide anion release, lipid oxidation, interleukin-1β (IL-1β) release, and adhesion to endothelium. The reduction in superoxide and lipid oxidation by AT seemed to be mediated by inhibition of protein kinase C. The aim of this study was to investigate the mechanism(s) by which AT inhibits IL-1β release. Potential mechanisms examined included its effect as an antioxidant and its inhibitory effects on protein kinase C and the cyclooxygenase-lipoxygenase pathways. Although AT decreased superoxide release from activated monocytes, superoxide dismutase and catalase had no effect on IL-1β release. Also, a similar antioxidant, β-tocopherol, had no effect on IL-1β release. The protein kinase C inhibitor, bisindolylmaleimide, did not inhibit IL-1β release from activated monocytes, in spite of AT decreasing protein kinase C activity. Leukotriene B4, a major product of 5-lipoxygenase, has been shown to augment IL-1β release. In the presence of AT, a significant reduction in leukotriene B4and IL-1β levels was observed, which was reversed by the addition of leukotriene B4. Similar observations were seen with specific inhibitors of 5-lipoxygenase. The product of cyclooxygenase, prostaglandin E2, has been shown to inhibit IL-1β activity in some systems. However, AT had no significant effect on prostaglandin E2levels in activated monocytes. In the presence of indomethacin, a cyclooxygenase inhibitor, AT inhibited IL-1β activity. Also, AT had no effect on IL-1β mRNA levels or stability, suggesting a posttranscriptional effect. Thus, in activated human monocytes, AT exerts a novel biological effect of inhibiting the release of the proinflammatory cytokine, IL-1β, via inhibition of the 5-lipoxygenase pathway.
Fibrinogen
Authors: Mennen Louise I. , Balkau Beverley , Vol Sylviane , Cacès Emile , Eschwège Evelyn
Published: June 2011

Abstract
—The relation between alcohol consumption and fibrinogen concentration was evaluated in a French population to investigate whether fibrinogen could explain part of the relation between alcohol consumption and cardiovascular disease. Cross-sectional data on self-reported alcohol consumption and fibrinogen, measured by the immunonephelometric method, of 4967 men and women aged 30 to 64 years were used. These subjects were volunteers for a free health checkup in the western central part of France from 1994 to 1996 and participated in the DESIR Study (Data from an Epidemiological Study on the Insulin Resistance syndrome). Alcohol consumption was strongly associated with fibrinogen concentration, with higher concentrations in those who were nondrinkers or who drank >60 g of alcohol per day. This U-shaped association was stronger among men than women. Consumption of wine and spirits was associated with fibrinogen, whereas consumption of beer or cider was not. Furthermore, smoking was positively associated with fibrinogen concentration, and in men the difference between nondrinkers and drinkers with the lowest fibrinogen level was higher in nonsmokers and ex-smokers than in current smokers. We conclude that moderate drinking may lower fibrinogen concentration. If fibrinogen is a causal risk factor for cardiovascular disease, it may be 1 of the variables that explain the protective effect of moderate alcohol consumption on cardiovascular disease.
Production of Angiotensin II by Homogeneous Cultures of Vascular Smooth Muscle Cells From Spontaneously Hypertensive Rats
Authors: Fukuda Noboru , Satoh Chikara , Hu Wen-Yang , Soma Masayoshi , Kubo Atsushi , Kishioka Hirobumi , Watanabe Yoshiyasu , Izumi Yoichi , Kanmatsuse Katsuo
Published: June 2011

Abstract
—Production of angiotensin II (Ang II) in spontaneously hypertensive rats (SHR)-derived vascular smooth muscle cells (VSMC) has now been investigated. A nonpeptide antagonist (CV-11974) of Ang II type 1 receptors inhibited basal DNA synthesis in VSMC from SHR, but it had no effect on cells from Wistar-Kyoto (WKY) rats. Ang II-like immunoreactivity, determined by radioimmunoassay after HPLC, was readily detected in conditioned medium and extracts of SHR-derived VSMC, whereas it was virtually undetectable in VSMC from WKY rats. Isoproterenol increased the amount of Ang II-like immunoreactivity in conditioned medium and extracts of SHR-derived VSMC, whereas the angiotensin-converting enzyme inhibitor delapril significantly reduced the amount of Ang II-like immunoreactivity in conditioned medium and extracts of these cells. Reverse transcription-polymerase chain reaction analysis revealed that the abundance of mRNAs encoding angiotensinogen, cathepsin D, and angiotensin-converting enzyme was greater in VSMC from SHR than in cells from WKY rats. The abundance of cathepsin D protein by Western blotting was greater in VSMC from SHR than in cells from WKY rats. Ang I-generating and acid protease activities were detected in VSMC from SHR, but not in cells from WKY rats. These results suggest that SHR-derived VSMC generate Ang II with increases in angiotensinogen, cathepsin D, and angiotensin-converting enzyme, which contribute to the basal growth. Production of Ang II by homogeneous cultures of VSMC is considered as a new mechanism of hypertensive vascular disease.