bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased Atherosclerosis in ApoE and LDL Receptor Gene Knock-Out Mice as a Result of Human Cholesteryl Ester Transfer Protein Transgene Expression
Authors: Plump Andrew S. , Masucci-Magoulas Lori , Bruce Can , Bisgaier Charles L. , Breslow Jan L. , Tall Alan R.
Published: June 2011

Abstract
—The plasma cholesteryl ester transfer protein (CETP) plays a major role in the catabolism of HDL cholesteryl ester (CE). CETP transgenic mice have decreased HDL cholesterol levels and have been reported to have either increased or decreased early atherosclerotic lesions. To evaluate the impact of CETP expression on more advanced forms of atherosclerosis, we have cross-bred the human CETP transgene into the apoE knock-out (apoE0) background with and without concomitant expression of the human apo A-I transgene. In this model the CETP transgene is induced to produce plasma CETP levels 5 to 10 times normal human levels. CETP expression resulted in moderately reduced HDL cholesterol (34%) in apoE0 mice and markedly reduced HDL cholesterol (76%) in apoE0/apoA1 transgenic mice. After injection of radiolabeled HDL CE, the CETP transgene significantly delayed the clearance of CE radioactivity from plasma in apoE0 mice, but accelerated the clearance in apoE0/apoA1 transgenic mice. ApoE0/CETP mice displayed an increase in mean atherosclerotic lesion area on the chow diet (approximately 2-fold after 2 to 4 months, and 1.4- to 1.6-fold after 7 months) compared with apoE0 mice (
P
<0.02). At 7 months apoA1 transgene expression resulted in a 3-fold reduction in mean lesion area in apoE0 mice (
P
<0.001). In the apoE0/apoA1 background, CETP produced an insignificant 1.3- to 1.7-fold increase in lesion area. In further studies the CETP transgene was bred onto the LDL receptor knock-out background (LDLR0). After 3 months on the Western diet, the mean lesion area was increased 1.8-fold (
P
<0.01) in LDLR0/CETP mice, compared with LDLR0 mice. These studies indicate that CETP expression leads to a moderate increase in atherosclerosis in apoE0 and LDLR0 mice, and suggest a proatherogenic effect of CETP activity in metabolic settings in which clearance of remnants or LDL is severely impaired. However, apoA1 overexpression has more dramatic protective effects on atherosclerosis in apoE0 mice, which are not significantly reversed by concomitant expression of CETP.
CD36, a Novel Receptor for Oxidized Low-Density Lipoproteins, Is Highly Expressed on Lipid-Laden Macrophages in Human Atherosclerotic Aorta
Authors: Nakata Atsuyuki , Nakagawa Yumiko , Nishida Makoto , Nozaki Shuichi , Miyagawa Jun-ichiro , Nakagawa Tsutomu , Tamura Ritsu , Matsumoto Kengo , Kameda-Takemura Kaoru , Yamashita Shizuya , Matsuzawa Yuji
Published: June 2011

Abstract—CD36 has been reported to be a receptor for oxidized LDL (Ox-LDL). In our previous study, the uptake of Ox-LDL in CD36-deficient macrophages was reduced by approximately 50% compared with that in control macrophages, suggesting an important role of CD36 as a receptor for Ox-LDL in humans. In the current study, we examined the immunohistochemical localization of CD36 in human aorta in comparison with that of scavenger receptor class A type I and type II (SRA). Cryostat sections were made from aortic tissues. For immunohistochemical staining, the following antibodies were used: (1) FA6-152, anti-CD36 antibody, and (2) SRI-2, which recognizes both type I and type II SRAs. Immunohistochemical staining for CD36 and SRA was performed using labeled streptavidin method. In macrophages scattered in aortic walls without atherosclerotic lesions, the expression of CD36 was hardly observed, whereas that of SRA was detected weakly but consistently. In contrast, in atherosclerotic lesions, macrophages around the core region showed a weak immunoreactivity to CD36 and a strong immunoreactivity to SRA. Furthermore, lipid-laden macrophages, which mainly existed in the core region, had a strongly positive immunoreactivity to CD36, but a low or moderate level of immunoreactivity to SRA. The distributions of CD36 and SRA were different from each other, and especially foamed, large-sized macrophages in atherosclerotic plaques tended to more abundantly express CD36 protein. These data demonstrate, for the first time, that the expression of both CD36 and SRA might be differentially regulated in aortic walls, and might play different roles in the formation of foam cells in atherosclerotic lesions.
Effects of Native, Triglyceride-Enriched, and Oxidatively Modified LDL on Plasminogen Activator Inhibitor-1 Expression in Human Endothelial Cells
Authors: Allison Beth A. , Nilsson Lennart , Karpe Fredrik , Hamsten Anders , Eriksson Per
Published: June 2011

Abstract
—Whereas VLDL has consistently been shown to induce a concentration-dependent increase in the expression of plasminogen activator inhibitor-1 (PAI-1) in human umbilical vein endothelial cells (HUVECs) and liver cells, variable effects have been reported for native and oxidatively modified LDL. In the present study, activation of PAI-1 protein and mRNA expression by native LDL (nLDL), UV-oxidized LDL (uvLDL), and triglyceride (TG)-enriched LDL was studied in HUVECs by using different incubation times and a wide range of lipoprotein concentrations. No significant increase of PAI-1 protein expression was observed after 4 hours of incubation with nLDL or uvLDL. However, PAI-1 protein secretion from HUVECs was markedly enhanced after 18 hours of incubation with uvLDL (200% increase at 10 μg/mL). Stimulation of PAI-1 protein expression in HUVECs by nLDL was seen, however, after increasing the TG content of the LDL particle. LDL enriched in phospholipid had no effect on PAI-1 secretion. PAI-1 mRNA levels on northern blot increased in parallel with the activation of PAI-1 protein expression by native and modified forms of LDL. Low concentrations of TG-enriched LDL (10 μg/mL) and higher concentrations of nLDL and uvLDL (100 μg/mL) were found to increase the binding of a VLDL-inducible transcription factor to the PAI-1 promoter. These results indicate that the TG content of the LDL particle influences PAI-1 expression in endothelial cells. Low concentrations of uvLDL enhanced PAI-1 protein and mRNA expression in the HUVECs after an 18-hour incubation but did not influence the VLDL-inducible transcription factor. This suggests that low levels of oxidized LDL increase PAI-1 expression by a different mechanism than VLDL and TG-enriched LDL.
Stat6 Activation Is Essential for Interleukin-4 Induction of P-Selectin Transcription in Human Umbilical Vein Endothelial Cells
Authors: Khew-Goodall Yeesim , Wadham Carol , Stein Brian N. , Gamble Jennifer R. , Vadas Mathew A.
Published: June 2011

Abstract—Chronic upregulation of P-selectin expression on the surface of the endothelium has been observed in and likely contributes to a number of chronic inflammatory diseases, including atherosclerosis. Agonists of P-selectin expression fall into 2 categories: those that induce a very rapid, transient increase, lasting only hours, and those that induce prolonged upregulation lasting days. It is the latter group, which includes interleukin-4 (IL-4), that is likely to be a mediator of chronic P-selectin upregulation. The increase in P-selectin expression induced by IL-4 results from increased transcriptional activation of the P-selectin gene. The aim of this study was to deduce the postreceptor signaling pathway(s) giving rise to the prolonged increase in P-selectin expression induced by IL-4. We demonstrate the existence of 2 functional signal transducer and activator of transcription 6 (Stat6) binding sites on the P-selectin promoter and further demonstrate, by functional analysis of the P-selectin promoter, that binding of activated Stat6 to at least 1 site is essential for IL-4-induction of P-selectin transcription. Site 1 (nucleotide[nt] −142) bound Stat6 with a higher affinity than did site 2 (nt −229), and this difference was reflected functionally as constructs in which only site 1 was functional showed full IL-4 inducibility, whereas constructs in which only site 2 was functional showed only 40% of maximal IL-4 inducibility. IL-4 also induced prolonged activation of Stat6, which was contingent on the continuous presence of IL-4. The sustained activation of Stat6 induced by IL-4 is likely to be a key factor leading to the prolonged activation of the P-selectin promoter, thereby resulting in prolonged P-selectin upregulation.
Protein Kinase C Mediates Basic Fibroblast Growth Factor–Induced Proliferation Through Mitogen-Activated Protein Kinase in Coronary Smooth Muscle Cells
Authors: Skaletz-Rorowski Adriane , Waltenberger Johannes , Müller Joachim G. , Pawlus Ewa , Pinkernell Kai , Breithardt Günter
Published: June 2011

Abstract
—Proliferation of coronary smooth muscle cells (cSMCs) contributes to the pathogenesis of arteriosclerosis and restenosis after angioplasty, and basic fibroblast growth factor (bFGF) is a powerful mitogen for cSMCs. In this study, we investigated the involvement of mitogen-activated protein kinase (MAPK), protein kinase C (PKC), and the transcription factor c-
myc
in bFGF-stimulated mitogenesis, as well as the functional relationship between these factors. cSMC stimulation with bFGF resulted in phosphorylation of p42 MAPK, as well as the phosphorylation and increased expression of c-
myc
. The MAPK kinase (MEK) inhibitor PD98059 blocked bFGF-stimulated MAPK phosphorylation and resulted in both a decrease of c-
myc
expression and inhibition of bFGF-stimulated DNA synthesis in cSMCs. bFGF also increased PKC activity in cSMCs in a time-dependent manner. The inhibition of PKC by chelerythrine or its downregulation by phorbol 12-myristate 13-acetate (PMA) inhibited bFGF-induced DNA synthesis and blocked the phosphorylation of MAPK and c-
myc
expression in response to bFGF. This indicates an involvement of phorbol ester–sensitive PKC isoforms in MAPK activation and mitogenic signaling by bFGF. Western blot analysis revealed the presence of the phorbol ester–sensitive isoforms PKC α, ε, and γ as well as the PKC isoforms ι, λ, μ, and ζ in cSMCs. In this study, we show that the MAPK cascade is required for bFGF-induced proliferation and that phorbol ester–sensitive PKC isoforms contribute to the bFGF-induced cSMC mitogenesis in cSMCs.
The Effect of Supplementation With Omega-3 Fatty Acids on Soluble Markers of Endothelial Function in Patients With Coronary Heart Disease
Authors: Johansen Odd , Seljeflot Ingebjørg , Høstmark Arne T. , Arnesen Harald
Published: June 2011

Abstract
—During progression of atherosclerosis the overlying endothelial cells alter their expression of some surface molecules. Circulating levels of such molecules may be quantified. We investigated the effect of omega-3 fatty acids (n-3 FA) on the levels of tissue plasminogen activator antigen, von Willebrand factor, and the soluble forms of thrombomodulin, P-selectin, E-selectin, and vascular cell adhesion molecule-1 in 54 patients with coronary heart disease. Twenty-three of the patients had taken 5.1 g/d n-3 FA for 6 months (group I) and 31 were given corn oil as placebo (group II). For another 4 weeks (“the study period”) they all got 5.1 g/d of n-3 FA. Compliance was confirmed by demonstration of changes in relevant fatty acids in serum phospholipids. At baseline, significant differences between the groups were found with lower median values of von Willebrand factor (128% versus 147%) and soluble thrombomodulin (24.9 versus 32.5 ng/mL) and higher median values of soluble E-selectin (41.4 versus 35.5 ng/mL) and soluble vascular cell adhesion molecule-1 (573 versus 473 ng/mL) in group I. During the study period differences in changes between the groups were found; tissue plasminogen activator antigen and soluble thrombomodulin decreased (
P
for difference between the groups 0.001 and 0.015, respectively), whereas soluble E-selectin and soluble vascular cell adhesion molecule-1 increased (
P
for difference between the groups <0.01 for both) in group II relative to group I. Our results indicate that n-3 FA supplementation decreases hemostatic markers of atherosclerosis, whereas markers of inflammation may be increased. The latter may be the result of lipid peroxidation as a simultaneous decrease of vitamin E and increase in thiobarbituric acid–reactive substances were observed.
Oncostatin M Induces Angiogenesis In Vitro and In Vivo
Authors: Vasse Marc , Pourtau Jérôme , Trochon Véronique , Muraine Marc , Vannier Jean-Pierre , Lu He , Soria Jeannette , Soria Claudine
Published: June 2011

Abstract—Neovascularization of the atherosclerotic plaque is responsible for its weakening and consequently for the complications of vascular disease. Macrophages are a source of growth factors that can modulate angiogenesis. In this study, we analyzed the effect of oncostatin M (OSM) on angiogenesis, as it could be involved in the development of atherosclerosis. The effect of OSM was compared with those of leukemia inhibitory factor (LIF) and interleukin-6 (IL-6). On human dermal microvasculature endothelial cells (HMEC-1s), OSM (22.5 to 112.5 pmol/L) induced a dose-dependent increase in cell proliferation greater than that induced by the classic angiogenic factors vascular endothelial growth factor (VEGF; 543 pmol/L) and basic fibroblast growth factor (bFGF; 1.1 nmol/L). LIF (19 to 475 pmol/L) induced only a 30% increase in cell proliferation, and IL-6 had no effect. Furthermore, in a modified Boyden-chamber model, OSM, LIF, and IL-6 were chemoattractant for HMEC-1s. In a tridimensional gel of fibrin, OSM increased tube formation and tube length, which were already noticeable by day 3. LIF and IL-6 induced a weaker effect that was only obvious by day 10. The angiogenic effect of OSM was also demonstrated in vivo in a rabbit corneal model: OSM was more potent than LIF, the length of the neovessels being longer with OSM than with LIF, whereas IL-6 was without effect. We tested factors that could be involved in the proliferative effect of OSM on HMEC-1s. OSM induced only a slight increase in the urokinase receptor and a 60% increase in VEGF secretion, whereas it does not modify IL-8 secretion or bFGF levels. The effect of OSM seems to depend on endothelial cell origin and cell species: OSM (up to 112.5 pmol/L) did not induce human umbilical vein endothelial cell proliferation and even had a small inhibitory effect (17%) on calf pulmonary artery endothelial cells. In conclusion, OSM induces an angiogenic effect on capillary endothelial cells, which could be, at least in part, implicated in pathological processes such as atherosclerosis or tumor growth.
Transcriptional Inhibition by Interleukin-6 of the Class A Macrophage Scavenger Receptor in Macrophages Derived From Human Peripheral Monocytes and the THP-1 Monocytic Cell Line
Authors: Liao Hai-Sun , Matsumoto Akiyo , Itakura Hiroshige , Doi Takefumi , Honda Makoto , Kodama Tatsuhiko , Geng Yong-Jian
Published: June 2011

Abstract
—Expression of the class A macrophage scavenger receptor (MSR) contributes to the uptake of modified low density lipoproteins (LDL) by macrophages and transformation of these cells into lipid-laden foam cells, which characterize atherosclerosis. Many environmental factors, in particular, proinflammatory cytokines and growth factors, can exert regulatory effects on MSR expression, whereas intracellular accumulation of cholesterol itself does not influence MSR levels to any considerable extent. In the present study, by using an in vitro model, we examined whether stimulation with interleukin-6 (IL-6), an immunoregulatory, multipotential cytokine, modulates the expression and activities of the MSR in macrophages. When treated with IL-6, macrophages derived from peripheral monocytes and phorbol 12-myristate 13-acetate (PMA)–differentiated THP-1 monocytic cells showed significantly reduced uptake and/or binding of the MSR ligand, acetylated LDL. This effect was paralleled by a reduction in the expression of MSR protein and mRNA. Analysis of MSR promoter activity in THP-1 cells transfected with an MSR promoter–reporter gene construct demonstrated decreased activity of the MSR promoter in IL-6–treated THP-1 macrophages. Electrophoretic mobility gel shift assay also showed a reduction in the binding of a transcription factor to the MSR promoter AP-1/ets elements in IL-6–treated cells. Thus, exposure to IL-6 may inhibit expression of the class A MSR in differentiated macrophages at transcriptional levels. This result suggests that this cytokine may modulate foam cell formation during atherogenesis.
Rapid Regression of Atherosclerosis Induced by Liver-Directed Gene Transfer of ApoE in ApoE-Deficient Mice
Authors: Tsukamoto Kazuhisa , Tangirala Rajendra , Chun Sam H. , Puré Ellen , Rader Daniel J.
Published: June 2011

Abstract
—Apolipoprotein E (apoE) is a multifunctional protein synthesized by the liver and tissue macrophages. ApoE-deficient mice have severe hyperlipidemia and develop accelerated atherosclerosis on a chow diet. Both liver-derived and macrophage-derived apoEs have been shown to reduce plasma lipoprotein levels and slow the progression of atherosclerosis in apoE-deficient mice, but regression of atherosclerosis has not been demonstrated in this model. We utilized second-generation adenoviruses to achieve hepatic expression of human apoE in chow-fed, apoE-deficient mice with established atherosclerotic lesions of different stages. As expected, hepatic expression of human apoE3 significantly reduced plasma cholesterol levels. Liver-derived apoE also accumulated substantially within preexisting atherosclerotic lesions, indicating that plasma apoE gained access to the arterial intima. Hepatic expression of human apoE3 for 6 weeks resulted in significant quantitative regression of both early fatty streak lesions as well as advanced, complex lesions in both the aortic root and the aortic arch. In addition, hepatic expression of apoE induced substantial morphological changes in lesions, including decreased foam cells and increased smooth muscle cells and extracellular matrix content. In parallel, human apoE4 and apoE2 were also expressed in the liver by using recombinant adenoviruses. ApoE4 reduced cholesterol levels to the same extent as did apoE3 and also prevented progression but did not induce significant regression of preexisting lesions. ApoE2 reduced cholesterol levels to a lesser degree than did apoE3 and apoE4 and lesion progression was reduced, but regression was not induced. In summary, (1) regression of preexisting atherosclerotic lesions in apoE-deficient mice can be rapidly induced by hepatic expression of apoE, despite the absence of macrophage-derived apoE; (2) the morphological changes seen in this model of regression resemble those in other animal models, induced over longer periods of time; (3) liver-derived apoE gained access to and was retained by intimal atherosclerotic lesions; and (4) apoE4 was less effective in inducing regression, despite its effects on plasma lipoproteins that were similar to those of apoE3. The rapid regression of preexisiting atherosclerotic lesions induced by apoE gene transfer in apoE-deficient mice could provide a convenient murine model for investigation of the molecular events associated with atherosclerosis regression.
Arteriographic assessment of coronary atherosclerosis. Review of current methods, their limitations, and clinical applications.
Authors: Brown B G , Bolson E L , Dodge H T
Published: June 2011

Coronary arteriography is presently the definitive procedure for characterizing the location and severity of coronary atherosclerosis; and despite certain reported limitations, we believe that the properly performed coronary arteriogram provides a true picture of the arterial lumen in life. Yet this widely-used clinical tool is currently limited by imprecise and, to a certain extent, inappropriate subjective methods of interpretation. More objective methods for analysis of the arteriographic information content have been described. These include caliper- and vernier- based systems for measuring relative arterial narrowing, computer-assisted methods for making accurate measurements of absolute stenosis dimensions, and photodensitometric methods for extracting three-dimensional information from a planar image of the stenosis. The availability of these objective techniques has resulted in a considerable increase in our understanding of pathogenic mechanisms in coronary disease. Advances include an expanded understanding of the mechanisms of action of nitroglycerin and verapamil and of the coronary artery constriction induced by drugs of isometric stress. Stenosis measurements have served as the basis for evaluation of certain noninvasive techniques used to detect coronary disease. An analytical approach has been developed to characterize the progression (and regression) of coronary disease from serial arteriograms. We believe clinical investigations based on these techniques hold considerable promise for further advances in the understanding of human coronary pathophysiology.
Clearance of Cationized LDL Cholesterol From a Muscle Depot Is Not Enhanced in Human Apolipoprotein A-IV Transgenic Mice
Authors: Stein Y. , Stein O. , Duverger N. , Halperin G. , Dabach Y. , Hollander G. , Ben-Naim M.
Published: June 2011

Abstract
—Human apolipoprotein A-IV (apoA-IV) transgenic mice fed an atherogenic diet were shown previously to develop less atherosclerosis than control mice. The question arose whether the antiatherogenic effect of human apoA-IV is due to enhancement of reverse cholesterol transport despite no increase in plasma high-density lipoprotein (HDL) cholesterol. We studied male and female mice overexpressing human apoA-IV and their wild-type (WT) controls, all of which were fed a chow diet. Plasma total and HDL cholesterol and total phospholipids were not increased in the transgenic mice, and regression analysis showed no correlation between plasma levels of cholesterol or phospholipids and plasma human apoA-IV. To study reverse cholesterol transport in vivo, the disappearance of cholesterol from a depot of [
3
H]cholesterol-labeled cationized low-density lipoprotein injected into the rectus femoris muscle was compared in high expressers of human apoA-IV and WT controls. The loss of radioactivity and the diminution of the exogenous cholesterol mass were determined on days 8 and 12 after injection. No enhanced loss of radioactivity or cholesterol mass was seen in the transgenic mice even at levels of 2500 mg/dL of human apoA-IV. In some instances, there was even slower loss of exogenous cholesterol (radioactivity and mass) in the transgenic mice. Although [
3
H]cholesterol efflux from cultured human skin fibroblasts and mouse peritoneal macrophages was only ≈30% higher in the presence of sera from high expressers of human apoA-IV, addition of phosphatidylcholine liposomes enhanced the efflux in both groups to the same extent. Another paradoxical finding was that the cholesterol esterification rate in plasma was 34% to 36% lower in human apoA-IV mice than in WT controls. In conclusion, even though apoA-IV was found previously to be atheroprotective under hypercholesterolemic conditions, high plasma levels of human apoA-IV did not enhance cholesterol mobilization in vivo in normocholesterolemic mice.
C-Reactive Protein in Offspring Is Associated With the Occurrence of Myocardial Infarction in First-Degree Relatives
Authors: Margaglione Maurizio , Cappucci Giuseppe , Colaizzo Donatella , Vecchione Gennaro , Grandone Elvira , Di Minno Giovanni
Published: June 2011

Abstract
—The relevance of elevated levels of C-reactive protein (CRP) in cardiovascular disease is gaining increasing recognition. A family history of coronary artery disease is a major determinant of coronary artery disease in the offspring. In a cohort of 1048 individuals without clinical evidence of atherosclerosis, we investigated the relationships between CRP levels and a family history of myocardial infarction. We measured CRP, fibrinogen, plasminogen activator inhibitor-1, total cholesterol, triglycerides, and some genetic polymorphisms: plasminogen activator inhibitor-1 (4G/5G), fibrinogen (Bβ-chain G→A
−455
), and angiotensin-converting enzyme insertion/deletion (I/D). Clinical data were collected by a World Health Organization–modified questionnaire for cardiovascular disease. When compared with subjects without first-degree relatives who had suffered a myocardial infarction (n=867), subjects with such first-degree relatives (n=181) were older (
P
=0.001), more often hypertensive (
P
<0.001), and homozygous for the 4G allele (4G/4G) of the plasminogen activator inhibitor-1 gene (
P
=0.003). In addition, they had a higher body mass index (
P
=0.036), raised plasma fibrinogen (
P
<0.007) and total cholesterol (
P
<0.001) concentrations, and CRP levels >0.33 mg/L (
P
=0.005). In a multiple logistic regression analysis, age (odds ratio [OR] 1.03, 95% confidence interval [95% CI] 1.01 to 1.05), total cholesterol (OR 1.35, 95% CI 1.11 to 1.65), plasminogen activator inhibitor-1 4G/4G (OR 1.72, 95% CI 1.20 to 2.45), and CRP levels >0.33 mg/L (OR 1.75, 95% CI 1.05 to 2.91) were all independently associated with a positive family history of myocardial infarction. We therefore conclude that raised levels of CRP independently identify the offspring of patients with a myocardial infarction.
Lysophosphatidylcholine Induces Urokinase-Type Plasminogen Activator and Its Receptor in Human Macrophages Partly Through Redox-Sensitive Pathway
Authors: Oka Hideki , Kugiyama Kiyotaka , Doi Hideki , Matsumura Toshiyuki , Shibata Hiroki , Miles Lindsey A. , Sugiyama Seigo , Yasue Hirofumi
Published: June 2011

Abstract—Urokinase-type plasminogen activator (uPA) and its cell surface receptor (uPAR) have been shown to be expressed in macrophages in atherosclerotic arterial walls, but the regulatory mechanisms of their expression remain unclear. The present study was performed to examine the effects of lysophosphatidylcholine (lysoPC), an important atherogenic lipid, on the expression of uPA and uPAR in human monocyte–derived macrophages. LysoPC upregulated the mRNA expression of uPA and uPAR, and it increased the protein expression of uPA in the culture medium and bound to the cell surface and of uPAR in the particulate fraction of the cells. LysoPC significantly increased the binding of the amino-terminal fragment of uPA to the treated cells and the cell-associated plasminogen activator activity. LysoPC stimulated superoxide anion production and increased intracellular oxidant levels in the cells. The combined incubation with reduced glutathione diethyl ester orN-acetylcysteine, antioxidants, suppressed the upregulation of uPA and uPAR mRNA and the increase in plasminogen activator activity by lysoPC. uPA and uPAR mRNA expression was also induced by the incubation with xanthine and xanthine oxidase, a superoxide anion–generating system. The results suggest that lysoPC increased the expression of uPA and uPAR and their functional activities in human monocyte–derived macrophages, at least in part through a redox-sensitive mechanism. This coordinate increase in the expression of uPA and uPAR in human macrophages by lysoPC could play an important role in plaque formation and disruption, arterial remodeling, and angiogenesis in atherosclerotic arterial walls.
Differential Expression of Rat Frizzled-Related
frzb-1
and Frizzled Receptor
fz1
and
fz2
Genes in the Rat Aorta After Balloon Injury
Authors: Mao Catherine , Malek Ouafae Tahlil-Ben , Pueyo Maria E. , Steg P. Gabriel , Soubrier Florent
Published: June 2011

Abstract
—Frzb-1 is a secreted protein, presenting similarity with the Wnt-binding domain of the frizzled family of receptors, which acts as an antagonist of Wnt signaling. Using mRNA differential display in the rat aorta balloon injury model, we identified overexpression of
Frzb
-1 mRNA and determined its cDNA sequence. By quantitative reverse transcription–polymerase chain reaction and RNase protection assay, a biphasic upregulation of
rFrzb-1
expression was observed, with significant peaks of a 1.7-fold increase at 4 days and a 1.5-fold increase at 3 weeks after aortic injury in vivo. In contrast, expression of the rat frizzled receptor genes
rfz1
and
rfz2
were transiently downregulated at 1 and 4 hours after balloon injury.
rFrzb-1
was expressed predominantly in rat aortic smooth muscle cells (RASMCs) and barely in aortic fibroblasts and endothelial cells (RAECs), whereas
rfz1
and
rfz2
were expressed in all of these cells when stimulated with serum. Transient downregulation of
rfz1
and
rfz2
expression was reproduced by stimulation of quiescent RASMCs with serum, platelet-derived growth factor-BB, or fibroblast growth factor-2. In contrast,
rFrzb-1
expression diminished slowly, to reach a 2-fold decrease 24 hours after growth factor stimulation, implying that quiescent RASMCs expressed higher levels of
rFrzb-1
mRNA than did proliferative ones. Overexpression of
rFrzb-1
in the aorta seemed to coincide with the arrest of RASMC proliferation occurring in the media 4 days and in the neointima 3 weeks after balloon injury. Our results demonstrate that
rfrzb-1
,
rfz1,
and
rfz2
are differentially regulated in response to arterial injury and that this modulation seems to follow the proliferative state of RASMCs
,
suggesting that these Wnt-signaling components may be involved in intimal vascular disease.
The ACAT Inhibitor Avasimibe Reduces Macrophages and Matrix Metalloproteinase Expression in Atherosclerotic Lesions of Hypercholesterolemic Rabbits
Authors: Bocan Thomas M. A. , Krause Brian R. , Rosebury Wendy S. , Mueller Sandra Bak , Lu Xiaokang , Dagle Catherine , Major Terry , Lathia Chetan , Lee Helen
Published: June 2011

Abstract
—Given the significance of cholesteryl ester (CE) accumulation in macrophage foam cell formation, we hypothesized that inhibitors of acyl-CoA:cholesterol
O
-acyltransferase (ACAT) would produce a histologically stable lesion by limiting macrophage enrichment and thereby a source of matrix metalloproteinases (MMPs). Male New Zealand White rabbits were sequentially fed a cholesterol/fat diet for 9 weeks, a fat-only diet for 6 weeks, and 25 mg/kg avasimibe for 7 to 8 weeks. Avasimibe had no effect on plasma total cholesterol exposure. Plasma avasimibe maximal concentration and 24-hour area-under-the-curve levels were 178 ng/mL and 2525 ng · h/mL, respectively, after 7 weeks of treatment with 25 mg/kg avasimibe. The median inhibitory concentration against human monocyte-macrophage ACAT was 12 ng/mL when determined in the absence of albumin, and aortic arch avasimibe levels were 25 ng/g of tissue wet weight. Avasimibe reduced thoracic aortic and iliac-femoral CE content by 39%, the extent of thoracic aortic lesions by 41%, aortic arch cross-sectional lesions area by 35%, and monocyte-macrophage area by 27%. The reduction in monocyte-macrophage area reflected a change in cell number and not cell size. In the iliac-femoral artery, avasimibe decreased monocyte-macrophage content by 77% and reduced the macrophage-to-lesion ratio from 0.16 to 0.05. Within the aortic arch, the catalytic activity of latent and active MMP-9 was reduced by 65% and 33%, respectively; latent and active MMP-1 and MMP-3 activity measured collectively was decreased by 52% and 60%, respectively, and MMP-2 was unchanged. Aortic arch MMP-9, tissue inhibitor of matrix metalloproteinase (TIMP)-1, and TIMP-2 mRNA levels were reduced 29% to 39%, and MMP-2 mRNA levels increased. We conclude that the bioavailable ACAT inhibitor avasimibe can directly limit macrophage accumulation, resulting in the histological appearance of mainly fibromuscular lesions, and can potentially stabilize preestablished atherosclerotic lesions by reducing MMP expression within the lesion.
Proliferative Effect of Lipoprotein Lipase on Human Vascular Smooth Muscle Cells
Authors: Mamputu Jean-Claude , Levesque Luc , Renier Geneviève
Published: June 2011

Abstract
—Vascular smooth muscle cell (VSMC) proliferation is a key event in the development and progression of atherosclerotic lesions. Accumulating evidence suggests that lipoprotein lipase (LPL) produced in the vascular wall may exert proatherogenic effects. The aim of the present study was to examine the effect of LPL on VSMC proliferation. Incubation of growth-arrested human VSMCs with purified endotoxin-free bovine LPL for 48 and 72 hours, in the absence of any added exogenous lipoproteins, resulted in a dose-dependent increase in VSMC growth. Addition of VLDLs to the culture media did not further enhance the LPL effect. Treatment of growth-arrested VSMCs with purified human or murine LPL (1 μg/mL) led to a similar increase in cell proliferation. Neutralization of bovine LPL by the monoclonal 5D2 antibody, irreversible inhibition, or heat inactivation of the lipase suppressed the LPL stimulatory effect on VSMC growth. Moreover, preincubation of VSMCs with the specific protein kinase C inhibitors calphostin C and chelerythrine totally abolished LPL-induced VSMC proliferation. In LPL-treated VSMCs, a significant increase in protein kinase C activity was observed. Treatment of VSMCs with heparinase III (1 U/mL) totally inhibited LPL-induced human VSMC proliferation. Taken together, these data indicate that LPL stimulates VSMC proliferation. LPL enzymatic activity, protein kinase C activation, and LPL binding to heparan sulfate proteoglycans expressed on VSMC surfaces are required for this effect. The stimulatory effect of LPL on VSMC proliferation may represent an additional mechanism through which the enzyme contributes to the progression of atherosclerosis.
Modulation of Expression of Endothelial Intercellular Adhesion Molecule-1, Platelet–Endothelial Cell Adhesion Molecule-1, and Vascular Cell Adhesion Molecule-1 in Aortic Arch Lesions of Apolipoprotein E–Deficient Compared With Wild-Type Mice
Authors: Zibara Kazem , Chignier Elza , Covacho Chantal , Poston Robin , Canard Georges , Hardy Patrick , McGregor John
Published: June 2011

Abstract—Human vascular adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1), platelet–endothelial cell adhesion molecule-1 (PECAM-1), and vascular cell adhesion molecule-1 (VCAM-1), are thought to play a critical role in the homing of leukocytes to sites of atherosclerotic lesions. However, very little is known about the expression of adhesion molecules in the vasculature of mice models, such as apolipoprotein E knockout (apoE−/−) mice, the lesions of which closely mimic human atherosclerotic lesions. This study has first quantitatively characterized the mean expression of endothelial adhesion molecules, lining the whole vessel intimal circumference, over a period of time (0 to 20 weeks of diet) in aortic arch lesions of male apoE-deficient compared with wild-type (C57BL/6) mice. These animals were fed a chow or a cholesterol-rich diet. ApoE−/−animals showed first an increase (at 6 weeks) and then a reduction (at 16 weeks) in the mean expression of ICAM-1 (P<0.05) and PECAM-1 (P<0.05) but not VCAM-1 levels. Such modulation of the mean expression of adhesion molecules was not observed in wild-type mice. Confirmation of immunohistochemistry results on ICAM-1 was obtained by Northern blots performed on the aortic arch of apoE and C57BL6 chow-fed mice over a period of 20 weeks. Moreover, the presence of VCAM-1 was also confirmed at the RNA level, on aortas of control and apoE mice, by reverse transcription–polymerase chain reaction. In the second part of the study, we assayed the levels of adhesion molecules, in different types of histologically defined atherosclerotic lesions, in apoE−/−animals fed for 20 weeks. All 3 adhesion molecules (ICAM-1, PECAM-1, and VCAM-1) were observed to be reduced in fibrofatty and complex lesions but not in fatty streaks or in areas without lesions. These results indicate that the expression of these adhesion molecules in apoE-deficient animals varies with the evolution of the plaque from a fatty to a fibrous stage.
Evidence for Association Between Polycystic Ovary Syndrome and Premature Carotid Atherosclerosis in Middle-Aged Women
Authors: Talbott Evelyn O. , Guzick David S. , Sutton-Tyrrell Kim , McHugh-Pemu Kathleen P. , Zborowski Jeanne V. , Remsberg Karen E. , Kuller Lewis H.
Published: June 2011

Abstract
—Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder characterized by obesity, hyperandrogenism, and insulin resistance. An adverse lipid profile has also been observed in PCOS-affected women, suggesting that these individuals may be at increased risk for coronary heart disease at a young age. The objective of the present study was to evaluate subclinical atherosclerosis among women with PCOS and age-matched control subjects. A total of 125 white PCOS cases and 142 controls, aged ≥30 years were recruited. Collection of baseline sociodemographic data, reproductive hormone levels, and cardiovascular risk factors was conducted from 1992 to 1994. During follow-up (1996 to 1999), these women underwent B-mode ultrasonography of the carotid arteries for the evaluation of carotid intima-media wall thickness (IMT) and the prevalence of plaque. A significant difference was observed in the distribution of carotid plaque among PCOS cases compared with controls: 7.2% (9 of 125) of PCOS cases had a plaque index of ≥3 compared with 0.7% (1 of 142) of similarly aged controls (
P
=0.05). Overall and in the group aged 30 to 44 years, no difference was noted in mean carotid IMT between PCOS cases and controls. Among women aged ≥45 years, PCOS cases had significantly greater mean IMT than did control women (0.78±0.03 versus 0.70±0.01 mm,
P
=0.005). This difference remained significant after adjustment for age and BMI (
P
<0.05). These results suggest that (1) lifelong exposure to an adverse cardiovascular risk profile in women with PCOS may lead to premature atherosclerosis, and (2) the PCOS-IMT association is explained in part by weight and fat distribution and associated risk factors. There may be an independent effect of PCOS unexplained by the above variables that is related to the hormonal dysregulation of this condition.
Intimal Hyperplasia Recurs After Removal of PDGF-AB and -BB Inhibition in the Rat Carotid Artery Injury Model
Authors: Leppänen Olli , Janjic Nebojsa , Carlsson Mari-Anne , Pietras Kristian , Levin Max , Vargeese Chandra , Green Louis S. , Bergqvist David , Östman Arne , Heldin Carl-Henrik
Published: June 2011

Abstract
—Several antagonists specific for platelet-derived growth factor (PDGF) or its receptors have recently been developed and shown to inhibit intimal hyperplasia formation in various animal models, but data investigating the durability of this intervention is limited. The present study was designed to investigate the potency of PDGF B-chain aptamer, a novel type of PDGF-AB and -BB antagonist, in the rat carotid model and to characterize intermediate-term effects on lesion formation. One hundred thirty-four animals were randomized to aptamer treatment or placebo. Daily treatment with the antagonist resulted in a 50% reduction in lesion size at 2 weeks (
P
<0.001). The beneficial effect involved increased apoptosis and possibly an interference with smooth muscle cell migration. Discontinuing administration 1 week earlier did not give any significant benefit compared with phosphate-buffered saline–treated controls. When the antagonist was administered for 2 weeks and the vessels analyzed 6 weeks later, the beneficial effect was lost and the treated lesions had a higher intima-media and area-cell ratio compared with the treated lesions in the 2-week–endpoint study. Our findings confirm a role of PDGF B-chain in intimal hyperplasia, but the successful use of PDGF antagonists may require either prolonged treatment or combination therapy with other agents.
Hypercholesterolemia Superimposed by Experimental Hypertension Induces Differential Distribution of Collagen and Elastin
Authors: Xu Chengpei , Zarins Christopher K. , Pannaraj Pia S. , Bassiouny Hisham S. , Glagov Seymour
Published: June 2011

Abstract
—We studied the mural distribution of collagen types I and III and tropoelastin in enhanced experimental atherogenesis induced in rabbits by hyperlipidemia superimposed by hypertension. Animals were fed a high-cholesterol diet for 5 weeks and also subjected to midthoracic aortic coarctation for 4 weeks. Serum cholesterol levels were increased and blood pressure was elevated proximal to the coarctation. Foam cell lesions developed in the aorta proximal to the coarctation. In situ hybridization and immunohistochemistry showed that gene expression of collagen types I and III and tropoelastin was upregulated, with a differential distribution across the arterial wall. New collagen type I was mainly distributed in the intima, the outer media, and the adventitia. New collagen type III was spread more uniformly across the wall, including the adventitia, whereas tropoelastin was mainly localized in intimal foam cell lesions. Morphometric data showed an increase in wall thickness. These results suggest that collagen types I and III play a role in remodeling of the aortic wall in response to hypertension. The remarkable involvement of the adventitia in this response indicates that the adventitia is an important component of the arterial wall. Tropoelastin is closely associated with foam cell lesion formation, suggesting a role for this component in atherogenesis as well.
Plasma Sphingomyelin Level as a Risk Factor for Coronary Artery Disease
Authors: Jiang Xian-cheng , Paultre Furcy , Pearson Thomas A. , Reed Roberta G. , Francis Charles K. , Lin Min , Berglund Lars , Tall Alan R.
Published: June 2011

Abstract
—Only a fraction of the clinical complications of atherosclerosis are explained by known risk factors. Animal studies have shown that plasma sphingomyelin (SM) levels are closely related to the development of atherosclerosis. SM carried into the arterial wall on atherogenic lipoproteins may be locally hydrolyzed by sphingomyelinase, promoting lipoprotein aggregation and macrophage foam cell formation. A novel, high-throughput, enzymatic method to measure plasma SM levels has been developed. Plasma SM levels were related to the presence of coronary artery disease (CAD) in a biethnic angiographic case-control study (279 cases and 277 controls). Plasma SM levels were higher in CAD patients than in control subjects (60±29 versus 49±21 mg/dL, respectively;
P
<0.0001). Moreover, the ratio of SM to SM+phosphatidylcholine (PC) was also significantly higher in cases than in controls (0.33±0.13 versus 0.29±0.10, respectively;
P
<0.0001). Similar relationships were observed in African Americans and whites. Plasma SM levels showed a significant correlation with remnant cholesterol levels (
r
=0.51,
P
<0.0001). By use of multivariate logistic regression analysis, plasma SM levels and the SM/(SM+PC) ratio were found to have independent predictive value for CAD after adjusting for other risk factors, including remnants. The odds ratio (OR) for CAD was significantly higher for the third and fourth quartiles of plasma SM levels (OR 2.81 [95% CI 1.66 to 4.80] and OR 2.33 [95% CI 1.38 to 3.92], respectively) as well as the SM/(SM+PC) ratio (OR 1.95 [95% CI 1.10 to 3.45] and OR 2.33 [95% CI 1.34 to 4.05], respectively). The findings indicate that human plasma SM levels are positively and independently related to CAD. Plasma SM levels could be a marker for atherogenic remnant lipoprotein accumulation and may predict lipoprotein susceptibility to arterial wall sphingomyelinase.
Altered Flow–Induced Arterial Remodeling in Vimentin-Deficient Mice
Authors: Schiffers P. M. H. , Henrion D. , Boulanger C. M. , Colucci-Guyon E. , Langa-Vuves F. , van Essen H. , Fazzi G. E. , Lévy B. I. , De Mey J. G. R.
Published: June 2011

Abstract
—The endothelial cytoskeleton plays a key role in arterial responses to acute changes in shear stress. We evaluated whether the intermediate filament protein vimentin is involved in the structural responses of arteries to chronic changes in blood flow (BF). In wild-type mice (V+/+) and in vimentin-deficient mice (V−/−), the left common carotid artery (LCA) was ligated near its bifurcation, and 4 weeks later, the structures of the occluded and of the contralateral arteries were evaluated and compared with the structures of arteries from sham-operated mice. Body weight and mean carotid artery BF did not differ between the strains, but LCA and right carotid artery (RCA) diameter (737±14 μm [LCA] and 723±14 μm [RCA] for V−/− versus 808±20 μm [LCA] and 796±20 μm [RCA] for V+/+) and medial cross-sectional area (CSAm) were significantly smaller in V−/− (21±1 and 22±2×10
3
μm
2
for LCA and RCA, respectively) than in V+/+ (28±2 and 28±3×10
3
μm
2
for LCA and RCA, respectively). In V+/+, LCA ligation eliminated BF in the occluded vessel (before ligation, 0.35±0.02 mL/min) and increased BF from 0.34±0.02 to 0.68±0.04 mL/min in the RCA. In V−/−, the BF change in the occluded LCA was comparable (from 0.38±0.05 mL/min to zero-flow rates), but the BF increase in the RCA was less pronounced (from 0.33±0.02 to 0.50±0.05 mL/min). In the occluded LCA of V+/+, arterial diameter was markedly reduced (−162 μm), and CSAm was significantly increased (5×10
3
μm
2
), whereas in the high-flow RCA of V+/+, carotid artery diameter and CSAm were not significantly modified. In the occluded LCA of V−/−, arterial diameter was reduced to a lesser extent (−77 μm) and CSAm was increased to a larger extent (10×10
3
μm
2
) than in V+/+. In contrast to V+/+, the high-flow RCA of V−/− displayed a significant increase in diameter (52 μm) and a significant increase in CSAm (5×10
3
μm
2
). These observations provide the first direct evidence for a role of the cytoskeleton in flow-induced arterial remodeling. Furthermore, they dissociate (1) between acute and chronic arterial responses to altered BF, (2) between alterations of lumen diameter and wall mass during arterial remodeling, and (3) between developmental and imposed flow-induced arterial remodeling.
Angiotensin II Stimulates Endothelial Vascular Cell Adhesion Molecule-1 via Nuclear Factor-κB Activation Induced by Intracellular Oxidative Stress
Authors: Pueyo Maria E. , Gonzalez Walter , Nicoletti Antonino , Savoie Françoise , Arnal Jean-François , Michel Jean-Baptiste
Published: June 2011

Abstract
—The recruitment of monocytes via the endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) is a key step in the formation of the initial lesion in atherosclerosis. Because angiotensin (Ang) II may be involved in this process, we investigated its role on the signaling cascade leading to VCAM-1 expression in endothelial cells. Ang II stimulates mRNA and protein expression of VCAM-1 in these cells via the AT
1
receptor. This effect was enhanced by
N
G
-nitro-
l
-arginine methyl ester, a nitric oxide synthase inhibitor, and blocked by pyrrolidinedithiocarbamate, an antioxidant molecule. Ang II activated the redox-sensitive transcription factor nuclear factor-κB and stimulated the degradation of both inhibitor of κB (IκB)α and IκBβ with different kinetics. The degradation of IκBs induced by Ang II was not modified by incubation with exogenous superoxide dismutase and catalase, suggesting that this effect was not mediated by the extracellular production of O
2
−
. In contrast, rotenone and antimycin, 2 inhibitors of the mitochondrial respiratory chain, inhibited the Ang II–induced IκB degradation, showing that generation of reactive oxygen species in the mitochondria is involved on Ang II action. BXT-51702, a glutathione peroxidase mimic, inhibited the effect of Ang II, and aminotriazole, an inhibitor of catalase, enhanced it, suggesting a role for H
2
O
2
in IκB degradation. This is confirmed by experiments showing that Ang II stimulates the intracellular production of H
2
O
2
in endothelial cells. These results demonstrate that Ang II induced an intracellular oxidative stress in endothelial cells, which stimulates IκB degradation and nuclear factor-κB activation. This activation enhances the expression of VCAM-1 and probably other genes involved in the early stages of atherosclerosis.