bluuebunny/crossref_metadata_2025 huggingface dataset:
Downregulation of the Selectin Ligand-Producing Fucosyltransferases Fuc-TIV and Fuc-TVII During Foam Cell Formation in Monocyte-Derived Macrophages
Authors: Cullen Paul , Mohr Susanne , Brennhausen Beate , Cignarella Andrea , Assmann Gerd
Published: June 2011

Abstract
Identification of genes expressed during foam cell formation is important for understanding the molecular basis of atherosclerosis. We used polymerase chain reaction (PCR)–based differential display to isolate differentially expressed cDNA species in foam cells induced by incubation of human monocyte-derived macrophages in the presence of acetylated or oxidized LDL. This led to identification of a 306-bp cDNA with 100% homology to type IV fucosyltransferase (Fuc-TIV), which was downregulated by factors of 20 and 3 in acetylated LDL– and oxidized LDL–loaded macrophages, respectively. This enzyme is sufficient for the expression of Lewis X and sialyl Lewis X, carbohydrate adhesion molecules that bind to receptors of the selectin family. Expression of a second fucosyltransferase (Fuc-TVII) that synthesizes sialyl Lewis X but not Lewis X was shown by quantitative reverse transcription–PCR to also be reduced, by 40% and 20% in acetylated LDL– and oxidized LDL–loaded macrophages, respectively. α-(1,3)-Fucosyltransferase enzyme activity was reduced in lysates from both acetylated LDL– and oxidized LDL–loaded cells. Analysis by flow cytometry showed reduced expression of the CD15 (corresponding to Lewis X) and CD15s (sialyl Lewis X) antigens on the surface of cells loaded with either acetylated or oxidized LDL. Transformation of macrophages into foam cells results in reduced expression of selectin-binding ligands on the surface of such cells.
A Common Mutation in the Methylenetetrahydrofolate Reductase Gene (C677T) Increases the Risk for Deep-Vein Thrombosis in Patients With Mutant Factor V (Factor V:Q
506
)
Authors: Cattaneo Marco , Tsai Michael Y. , Bucciarelli Paolo , Taioli Emanuela , Zighetti Maddalena L. , Bignell Michelle , Mannucci Pier Mannuccio
Published: June 2011

Abstract
Hyperhomocysteinemia is a frequent risk factor for deep-vein thrombosis. A common mutation (C677T) in the gene encoding for methylenetetrahydrofolate reductase (MTHFR) is responsible, in the homozygous state, for decreased enzyme activity and mild hyperhomocysteinemia and is associated with increased risk for cardiovascular disease. We studied the prevalence of C677T MTHFR in 77 patients with deep-vein thrombosis and in 154 age- and sex-matched healthy control subjects. In the same individuals, we also evaluated the frequency of the coexistence of C677T MTHFR with mutant factor V:Q
506
, a common risk factor for deep-vein thrombosis. Sixteen patients (20.8%) and 35 control subjects (22.7%) were homozygous for the C677T MTHFR mutation (odds ratio [OR]=0.8, 95% confidence interval [CI]=0.4-2.0). Sixteen patients (20.8%) and 4 control subjects (2.6%) had factor V:Q
506
; of them, 10 patients and 3 control subjects had isolated factor V:Q
506
(adjusted OR=6.3, 95% CI=1.6-25.3) and 6 patients and 1 control subject also had C677T MTHFR (adjusted OR=17.3, 95% CI=2.0-152.9). The OR for the coexistence of the two mutations was 65% to 75% higher than the expected joint effect calculated by either an additive (OR=6.0) or multiplicative(OR=4.4) model . The homozygous C677T mutation of MTHFR per se is not a risk factor for deep-vein thrombosis but increases the risk associated with factor V:Q
506
. Due to the high prevalence of C677T MTHFR, it is likely that previous studies, which did not look for this mutation, overestimated the relative risk of thrombosis associated with factor V:Q
506
alone.
Effect of 17β-Estradiol on Metabolism of Acetylated Low-Density Lipoprotein by THP-1 Macrophages in Culture
Authors: R.W. St Clair Sulistiyani
Published: June 2011

Abstract
Evidence from numerous epidemiological and animal studies has shown a protective effect of estrogens on the development of atherosclerosis. Since not all of the beneficial effects of estrogen can be explained by alterations in plasma lipoprotein profiles, estrogens may have a direct effect on the arterial wall on one or more of the key steps in the pathogenesis of atherosclerosis. In the present study we tested the hypothesis that estrogens decrease macrophage foam cell formation by reducing lipoprotein uptake via the scavenger receptor pathway. Incubation of the human THP-1 macrophage cell line with 17β-estradiol reduced the uptake and metabolism of
125
I-labeled human acetylated LDL (acLDL) in a concentration-dependent manner (from 10
−9
to 10
−5
mol/L) by 30% to 40% at the highest concentrations used. This decrease was accompanied by a reduction in cholesterol accumulation and esterification. When chloroquine was used to block lysosomal degradation, 17β-estradiol retained its ability to decrease accumulation of acLDL. This finding suggested that the effect of estrogen occurs before degradation of acLDL by lysosomes. 17β-Estradiol had no effect on binding of
125
I-acLDL at 4°C. When
125
I-acLDL was bound at 4°C and warmed to 37°C, less acLDL was internalized and degraded in cells treated with 17β-estradiol, due to greater dissociation of the bound acLDL from the surface of estrogen-treated cells during internalization. We conclude that as a result of the estrogen-induced increase in dissociation of acLDL, less lipoprotein cholesterol is delivered to macrophages, resulting in a reduced rate of foam cell formation. This may be one mechanism by which estrogens reduce the development of atherosclerosis.
Cytomegalovirus Infection, Lipoprotein(a), and Hypercoagulability: An Atherogenic Link?
Authors: Nieto F. Javier , Sorlie Paul , Comstock George W. , Wu Kenneth , Adam Erwin , Melnick Joseph L. , Szklo Moyses
Published: June 2011

Abstract
A link between cytomegalovirus (CMV) infection and atherosclerosis has been suggested by experimental, clinical, and epidemiologic studies. We investigated the association between CMV antibody titers in serum collected in 1974 in 300 adult residents in Washington County, Md, and hemostatic parameters in plasma collected in 1987 through 1989, when these individuals participated in the baseline examination of the Atherosclerosis Risk in Communities Study. The cross-sectional association of CMV serum antibodies and hemostatic parameters was also explored in another set of Atherosclerosis Risk in Communities cases and controls. In the longitudinal analyses, CMV titers in 1974 were directly associated with 1987 through 1989 plasma levels of von Willebrand factor, factor VIII, and protein C and negatively associated with activated partial thromboplastin time. In the cross-sectional analyses, CMV titers were directly related to antithrombin III and fibrinogen levels. When the association between CMV antibodies and atherosclerosis was examined in stratified analyses, a significant association was restricted to individuals with high levels of lipoprotein(a) and fibrinogen. These results are compatible with previous evidence suggesting that CMV virus might have procoagulant properties. The possible synergism of CMV infection and resulting hypercoagulability with reduced fibrinolysis due to increased lipoprotein(a) levels deserves further investigation.
Efficacy and Safety of a New Hydroxymethylglutaryl-Coenzyme A Reductase Inhibitor, Atorvastatin, in Patients with Combined Hyperlipidemia: Comparison with Fenofibrate
Authors: Ooi Teik C. , Heinonen Therese , Alaupovic Petar , Davignon Jean , Leiter Lawrence , Lupien Paul J. , Sniderman Allan D. , Tan Meng H. , Tremblay Gerald , Sorisky Alexander , Shurzinske Linda , Black Donald M.
Published: June 2011

AbstractThis 24-week, randomized, open-label multicenter study evaluated the efficacy and safety of atorvastatin compared with fenofibrate in the treatment of patients with combined hyperlipidemia (CHL). Following a 6-week baseline period, 84 patients with CHL were randomly assigned to either atorvastatin treatment, 10 mg QD for 12 weeks increasing to 20 mg QD for 12 weeks, or fenofibrate treatment, 100 mg TID for 24 weeks. Changes from baseline in lipid parameters were evaluated at weeks 12 and 24. At both 10- and 20-mg doses, atorvastatin treatment resulted in significantly greater reductions in LDL cholesterol, apolipoprotein (apo) B, total cholesterol, LDL-apoB, and lipoprotein-B compared to 300-mg fenofibrate treatment (P<.05). While atorvastatin also resulted in clinically significant reductions in triglyceride, VLDL cholesterol, apoB in VLDL, triglyceride in VLDL, and apoC-III and significant increases in HDL cholesterol and apoA-I levels, fenofibrate was more effective than atorvastatin in altering all these parameters. However, by significantly affecting both the cholesterol-rich and triglyceride-rich particles, atorvastatin holds promise as a lipid-regulator able to adequately treat a broad range of patients that includes those with CHL.
Alterations in Endothelial F-Actin Microfilaments in Rabbit Aorta in Hypercholesterolemia
Authors: Colangelo Sandra , Langille B. Lowell , Steiner George , Gotlieb Avrum I.
Published: June 2011

Abstract
—The current study tests whether hypercholesterolemia influences the distribution of endothelial cell microfilaments during the initiation and growth of fatty streak–type lesions. We classified the lesions occurring over a 20-week period into four types based on the location and extent of macrophage infiltration observed microscopically. The earliest lesion was characterized by leukocytes adherent to the endothelial surface. Minimal lesions were characterized by a few cells in the subendothelium. Intermediate lesions consisted of numerous subendothelial leukocytes in a minimally raised lesion. Advanced fatty streak lesions were elevated, with several layers of leukocytes. The organization of peripheral junctional actin (the dense peripheral band) and of central endothelial cell actin microfilament bundles was studied in each of these lesions by using fluorescent microscopy. We found that in the aorta away from branch sites and in areas away from lesions, the central microfilament distribution was unaffected by hypercholesterolemia. The macrophages entered the wall without any identifiable reorganization in the microfilaments. During the accumulation of subendothelial macrophages in minimal and intermediate lesions, stress fibers were initially increased in comparison to lesion-free areas. In raised advanced lesions, the central microfilaments became thinner and disappeared. However, at flow dividers, where central stress fibers are normally prominent, endothelial cells on the surface of intermediate lesions showed a reduction in central fibers, and peripheral bands became prominent. This finding was associated with changes in cell shape from elongated to cobblestone type. Thus, actin microfilament bundles in endothelial cells underwent substantial changes in distribution during the accumulation of subendothelial macrophages, forming hypercholesterolemia-induced fatty streak–type lesions. These changes may influence endothelial substrate adhesion, permeability, or repair after injury.
Flow-Mediated Regulation of G-Protein Expression in Cocultured Vascular Smooth Muscle and Endothelial Cells
Authors: Redmond Eileen M. , Cahill Paul A. , Sitzmann James V.
Published: June 2011

Abstract—G-proteins have been implicated in the transduction of a number of flow-induced responses. We determined whether flow can modulate vascular endothelial or smooth muscle cell G-protein signaling. By use of a perfused transcapillary coculture system that permits the chronic exposure of cultured endothelial cells (ECs) and smooth muscle cells (SMCs) to physiological shear stresses, cocultures were exposed to stepwise increases in flow up to (1) 2 mL/min (low flow: 0.5 dyne/cm2), or (2) 44 mL/min (high flow: 15 dyne/cm2) and maintained for 72 hours before SMCs and ECs were harvested separately. Using Western blot analysis, EC Giα3expression was significantly increased (41±2.9%) by high-flow conditions compared with low-flow. The changes in G-protein expression were associated with a significant increase in endothelial nitric oxide synthase (eNOS) activity, elevated prostacyclin levels in the perfusing media, increased pertussis toxin–catalyzed ADP ribosylation of Giα substrates, and enhanced agonist-stimulated GTPase activity in cocultured ECs. In contrast, high flow induced a significant decrease in Giα1–2expression (57±5%) in SMCs cocultured with ECs, an effect that was endothelium dependent, inhibited by indomethacin, and correlated with a decrease in pertussis toxin–catalyzed ADP ribosylation of Giα substrates, reduced agonist-stimulated GTPase activity, and enhanced basal and G-protein–stimulated adenylyl cyclase activity. These data demonstrate that flow mediates selective changes in EC and SMC G-protein expression concomitant with changes in G-protein functionality and cellular signaling capacity. Moreover, flow-induced changes in SMC G-protein signaling capacity are endothelium dependent and require a cyclooxygenase product. G-protein modulation may thus represent an important mechanism whereby hemodynamic forces regulate vessel wall function.
Metabolic Determinants Are Much More Important Than Genetic Polymorphisms in Determining the PAI-1 Activity and Antigen Plasma Concentrations
Authors: Henry M. , Tregouët D.A. , Alessi M.C. , Aillaud M.F. , Visvikis S. , Siest G. , Tiret L. , Juhan-Vague I.
Published: June 2011

Abstract
—Increased plasma plasminogen activator inhibitor-1 (PAI-1) concentration has been identified as a risk factor for coronary heart disease. We investigated the relative contribution of both metabolic factors involved in the insulin resistance (IR) syndrome and polymorphisms of the PAI-1 gene to plasma levels of PAI-1 in 228 healthy nuclear white families from the Stanislas Cohort. Variables related to IR included body mass index, waist-to-hip ratio, fasting insulin, triglyceride, and HDL cholesterol. Five PAI-1 gene polymorphisms were studied, including a newly described G+12078A substitution in the 3′ region. A sex difference was observed, with fathers exhibiting higher IR state and PAI-1 levels and stronger correlations between PAI-1 and IR variables than mothers. Such a difference was not observed in offspring. Family correlations were of similar magnitude for fibrinolytic parameters and IR variables. The PAI-1 genotypes A−844G, −675 4G/5G, and G+12078A polymorphisms, which were in strong linkage disequilibrium, were associated with plasma PAI-1 levels. In multivariate analysis, IR explained a major part of PAI-1 variability (49% in fathers, 29% in mothers), whereas polymorphisms had only a minor contribution, explaining 3% of variability in women and having no significant effect in men. We conclude that plasma levels of PAI-1 are, in a healthy population, primarily determined by the IR syndrome, this relationship being stronger in males. The contribution of the PAI-1 gene seems larger in females. These results deserve special attention for understanding the relationships observed between fibrinolytic parameters and the risk of developing a cardiovascular ischemic event.
Polymorphonuclear Leukocytes Induce PDGF Release From IL-1β–Treated Endothelial Cells
Authors: Totani L. , Cumashi A. , Piccoli A. , Lorenzet R.
Published: June 2011

Abstract—Polymorphonuclear leukocytes (PMNs) and endothelial cells interact at sites of vascular injury during inflammatory response and during the development of atherosclerotic lesions. Such close proximity leads to the modulation of several of the biological functions of the 2 cell types. Because we have shown previously that PMNs enhance release of growth factors from resting endothelial cells, we decided to evaluate whether coincubation of PMNs with interleukin-1β (IL-1β)–stimulated human umbilical vein endothelial cells (HUVEC) could further modulate mitogen release from HUVEC. We found that PMN-HUVEC coincubation resulted in a 10-fold increase in mitogen release, compared with HUVEC alone (14±6 versus 1.3±0.1). When PMNs were incubated with IL-1β–treated HUVEC, a further increase in mitogen release (up to 35-fold) was observed. The mitogenic activity was immunologically related to platelet-derived growth factor (PDGF) because the activity was abolished by an anti-PDGF antibody. PDGF-AB antigen, detected in low concentrations in conditioned medium from HUVEC alone, was increased 4-fold when IL-1β or PMNs were incubated with HUVEC and dramatically upregulated (up to 40-fold) when PMNs were cocultured with IL-1β–treated HUVEC. The presence of the protease inhibitor eglin C abolished mitogenic activity generation, suggesting a role for PMN-derived elastase and cathepsin G. Indeed, purified elastase and cathepsin G mimicked PMN-induced mitogen release from HUVEC. Because PMNs firmly adhered to IL-1β–treated HUVEC, we investigated the role of cell-cell adhesion in mitogen release. Adhesion and PDGF release were inhibited by ≈60% in the presence of anti-CD11a/CD18 and anti-intercellular adhesion molecule-1 monoclonal antibodies. This study suggests a new role for PMNs and their interaction with endothelium in pathological conditions in which intimal hyperplasia is a common feature.
Expression of ACAT-1 Protein in Human Atherosclerotic Lesions and Cultured Human Monocytes-Macrophages
Authors: Miyazaki Akira , Sakashita Naomi , Lee Oneil , Takahashi Kiyoshi , Horiuchi Seikoh , Hakamata Hideki , Morganelli Peter M. , Chang Catherine C. Y. , Chang Ta-Yuan
Published: June 2011

Abstract
—The acyl coenzyme A:cholesterol acyltransferase (ACAT) gene was first cloned in 1993 (Chang et al,
J Biol Chem
. 1993;268:20747–20755; designated ACAT-1). Using affinity-purified antibodies raised against the
N
-terminal portion of human ACAT-1 protein, we performed immunohistochemical localization studies and showed that the ACAT-1 protein was highly expressed in atherosclerotic lesions of the human aorta. We also performed cell-specific localization studies using double immunostaining and showed that ACAT-1 was predominantly expressed in macrophages but not in smooth muscle cells. We then used a cell culture system in vitro to monitor the ACAT-1 expression in differentiating monocytes-macrophages. The ACAT-1 protein content increased by up to 10-fold when monocytes spontaneously differentiated into macrophages. This increase occurred within the first 2 days of culturing the monocytes and reached a plateau level within 4 days of culturing, indicating that the increase in ACAT-1 protein content is an early event during the monocyte differentiation process. The ACAT-1 protein expressed in the differentiating monocytes-macrophages was shown to be active by enzyme assay in vitro. The high levels of ACAT-1 present in macrophages maintained in culture can explain the high ACAT-1 contents found in atherosclerotic lesions. Our results thus support the idea that ACAT-1 plays an important role in differentiating monocytes and in forming macrophage foam cells during the development of human atherosclerosis.
Postprandial Lipemic Response Is Modified by the Polymorphism at Codon 54 of the Fatty Acid–Binding Protein 2 Gene
Authors: Ågren Jyrki J. , Valve Raisa , Vidgren Helvi , Laakso Markku , Uusitupa Matti
Published: June 2011

Abstract
—Polymorphism of the fatty acid–binding protein 2 (FABP2) gene has been shown to affect the affinity of intestinal FABP for fatty acids. This could cause changes in postprandial triglyceride metabolism. In the present study, postprandial lipemia was studied in normotriglyceridemic subjects with genetic variation in the FABP2 gene. Oral fat-loading tests were performed in 8 subjects homozygous for the Thr-encoding allele at codon 54 of the FABP2 gene and in 7 subjects homozygous for the Ala-encoding allele (wild type). There were no significant differences between these 2 groups in age, body mass index, fasting plasma triglyceride and cholesterol levels, or fasting glucose and insulin levels. The increase of plasma triglyceride concentration after the fat test meal was significantly greater in subjects who were homozygous for the Thr-54 allele (area under the response curve, 4.27±1.31 versus 2.49±1.18 mmol/L · h
−1
,
P
=0.04). The difference was seen in both chylomicron (2.51±0.98 versus 1.41±0.74 mmol/L · h
−1
,
P
=0.03) and very low-density lipoprotein triglycerides (1.57±0.77 versus 0.99±0.40 mmol/L · h
−1
,
P
=0.04). Postprandial triglyceride response correlated with fasting triglycerides in the Ala-54 homozygotes (
r
=0.79,
P
=0.05) but not in the Thr-54 homozygotes (
r
=0.09), who showed a strong correlation between triglyceride and insulin responses (
r
=0.83,
P
=0.02). With reservations related to a small number of subjects studied, these results indicate that the Thr-encoding allele of the FABP2 gene is associated with increased postprandial lipemia. The lipemic response was associated with postprandial insulin response, suggesting that in the Thr-54 homozygotes, altered postprandial lipemia may also modify insulin action or vice versa.
Paraoxonase Active Site Required for Protection Against LDL Oxidation Involves Its Free Sulfhydryl Group and Is Different From That Required for Its Arylesterase/Paraoxonase Activities
Authors: Aviram Michael , Billecke Scott , Sorenson Robert , Bisgaier Charles , Newton Roger , Rosenblat Mira , Erogul John , Hsu Cary , Dunlop Cristina , La Du Bert
Published: June 2011

Abstract
—Human serum paraoxonase (PON 1) exists in 2 major polymorphic forms (Q and R), which differ in the amino acid at position 191 (glutamine and arginine, respectively). These PON allozymes hydrolyze organophosphates and aromatic esters, and both also protect LDL from copper ion–induced oxidation. We have compared purified serum PONs of both forms and evaluated their effects on LDL oxidation, in respect to their arylesterase/paraoxonase activities. Copper ion–induced LDL oxidation, measured by the production of peroxides and aldehydes after 4 hours of incubation, were reduced up to 61% and 58%, respectively, by PON Q, but only up to 46% and 38%, respectively, by an equivalent concentration of PON R. These phenomena were PON-concentration dependent. Recombinant PON Q and PON R demonstrated similar patterns to that shown for the purified serum allozymes. PON Q and PON R differences in protection of LDL against oxidation were further evaluated in the presence of glutathione peroxidase (GPx). GPx (0.1 U/mL) alone reduced copper ion–induced LDL oxidation by 20% after 4 hours of incubation. The addition of PON R to the above system resulted in an additive inhibitory effect on LDL oxidation, whereas PON Q had no such additive effect. The 2 PON allozymes also differed by their ability to inhibit initiation, as well as propagation, of LDL oxidation. PON Q was more efficient in blocking LDL oxidation if added when oxidation was initiated, whereas PON R was more potent when added 1 hour after the initiation of LDL oxidation. These data suggest that the 2 allozymes act on different substrates. Both PON allozymes were also able to reduce the oxidation of phospholipids and cholesteryl ester. PON Q arylesterase activity was reduced after 4 hours of LDL oxidation by only 28%, whereas the arylesterase activity of PON R was reduced by up to 55%. Inactivation of the calcium-dependent PON arylesterase activity by using the metal chelator EDTA, or by calcium ion removal on a Chelex column, did not alter PON’s ability to inhibit LDL oxidation. However, blockage of the PON free sulfhydryl group at position 283 with
p
-hydroxymercuribenzoate inhibited both its arylesterase activity and its protection of LDL from oxidation. Recombinant PON mutants in which the PON free sulfhydryl group was replaced by either alanine or serine were no longer able to protect against LDL oxidation, even though they retained paraoxonase and arylesterase activities. Overall, these studies demonstrate that PON’s arylesterase/paraoxonase activities and the protection against LDL oxidation do not involve the active site on the enzyme in exactly the same way, and PON’s ability to protect LDL from oxidation requires the cysteine residue at position 283.
Complement C6 Deficiency Protects Against Diet-Induced Atherosclerosis in Rabbits
Authors: Schmiedt Walther , Kinscherf Ralf , Deigner Hans-Peter , Kamencic Huse , Nauen Olaf , Kilo Juliane , Oelert Hellmut , Metz Jürgen , Bhakdi Sucharit
Published: June 2011

Abstract—Low-density lipoprotein (LDL) can be transformed to an atherogenic moiety by nonoxidative, enzymatic degradation. Enzymatically degraded LDL induces macrophage foam cell formation, provokes release of cytokines, and also activates complement. To determine whether complement activation may contribute to atherogenesis, 6 pairs of homozygous C6-deficient rabbits and their non–C6-deficient heterozygous siblings were fed a cholesterol-rich diet for 14 weeks. Cholesterol levels and plasma lipoprotein profiles of the animals in the C6-competent and C6-deficient groups did not significantly differ, and the high density lipoprotein and LDL cholesterol ratios at the end of the experiment were 0.07±0.01 and 0.08±0.01 (SEM), respectively. However, differences in atherosclerotic plaque formation were discernible macroscopically, with extensive aortic lesions being visible in all C6-competent animals and absent in all C6-deficient animals. Aortas were sectioned from thorax to abdomen, and 10 sections were stained from each aorta. Quantification of atherosclerotic lesions and lumen stenosis with the use of computer-based morphometry documented a dramatic protective effect of C6 deficiency on the development of diet-induced atherosclerosis. We conclude that the terminal complement sequence is centrally involved in atherosclerotic lesion progression.
Haplotypes of the ApoA-I/C-III/A-IV Gene Cluster and Familial Combined Hyperlipidemia
Authors: Tahvanainen Esa , Pajukanta Päivi , Porkka Kimmo , Nieminen Sari , Ikävalko Liisa , Nuotio Ilpo , Taskinen Marja-Riitta , Peltonen Leena , Ehnholm Christian
Published: June 2011

Abstract—Familial combined hyperlipidemia (FCHL) is the most frequent familial lipoprotein disorder associated with premature coronary heart disease. However, no genetic defect(s) underlying FCHL has been identified. A linkage between FCHL and the apoA-I/C-III/A-IV gene cluster has been reported but not verified in other populations. A recent study identified FCHL susceptibility haplotypes at this gene cluster. To study whether such haplotypes are also associated with FCHL susceptibility in Finns, we studied 600 well-defined Finnish FCHL patients and their relatives belonging to 28 extended FCHL families by using haplotype, linkage, sib-pair, and linkage disequilibrium analyses. The genotypes of theMspI polymorphisms were associated with total serum cholesterol (P<0.01) and apoB (P<0.05) levels in spouses, which represent the general Finnish population. However, no evidence of direct involvement of any of these loci or their specific haplotypes in the expression of FCHL in the Finnish FCHL families was found.
Differences in Near-Wall Shear Rate in the Carotid Artery Within Subjects Are Associated With Different Intima-Media Thicknesses
Authors: Kornet Lilian , Lambregts Jacques , Hoeks Arnold P. G. , Reneman Robert S.
Published: June 2011

Abstract
—In the common carotid artery, reflections originating from the periphery and the flow divider may affect the shape of the flow velocity profile and, hence, near-wall shear rate (WSR) differently just before the bifurcation (location B) than 20 to 30 mm farther upstream (location A). Recent developments in ultrasound technology allow the assessment of WSR and intima-media thickness (IMT) at the same site in the carotid artery in vivo. We therefore determined WSR at locations A and B and investigated whether the differences between both sites, if any, were associated with different IMTs and different mechanical properties of the arterial wall. The effect of age on the possible differences was assessed as well. The study was performed on presumably healthy volunteers (n=53). In all individuals, IMT was larger at location B than at location A. The relative difference in IMT between both locations was not affected by age. No significant differences in diameter and distension were found between locations. Near peak systolic and near mean WSR at the posterior wall (PWSR
p
and MWSR
p
, respectively) were significantly lower at location B than at location A. The relative differences in PWSR
p
and MWSR
p
between both locations within subjects were independent of age. The velocity profiles were more blunted at location A than at location B. PWSR
p
and MWSR
p
significantly decreased and IMT significantly increased with age at both locations. IMT was negatively correlated with PWSR
P
and MWSR
P
at location B, but this correlation was not significant at location A. In summary, in the common carotid artery, the lower WSR near the bifurcation, as compared with 20 to 30 mm upstream, is associated with a larger IMT than at the more proximal site. The relative difference between both locations within subjects is independent of age.
Direct Assessment of Lipoprotein Outflow From In Vivo–Labeled Arterial Tissue as Determined in an In Vitro Perfusion System
Authors: Björnheden T. , Bondjers G. , Wiklund O.
Published: June 2011

Abstract
—The rate of cholesterol deposition during the atherosclerotic process is determined by the balance between the inflow and outflow of plasma lipoproteins in the arterial wall. Whereas the rate of inflow may be measured directly, the rate of outflow has most often been calculated indirectly from lipoprotein uptake by using the 2-compartment model. One objection against such calculations is that lipoprotein binding is not being considered. In the present study 2 different protocols were used to obtain a direct measure of the outflow of lipoproteins from atherosclerotic rabbit aortas. Thus, 3 rabbits with experimental atherosclerosis were given
125
I-LDL intravenously and 3 were given [
14
C]cholesterol perorally. Twenty-four hours later the aortas were removed and the outflow of label was monitored during in vitro perfusion. Despite the different protocols, our results were consistent and indicated that fractional loss relative to whole tissue was ≈0.01 pool/h, which is 1 order of magnitude lower than current estimates based on the 2-compartment model (0.04 to 0.4 pool/h). Furthermore, whereas as much as 2/3 to 3/4 of the tracer that had entered the arterial wall was effectively trapped, the remainder equilibrated at a faster rate (0.06 pool/h). In conclusion, it seems that tissue binding constitutes a prominent and possibly underrated mechanism of lipoprotein deposition, at least in the atherosclerotic rabbit aorta. Furthermore, this means that current estimates of lipoprotein exchange parameters based on the 2-compartment model (eg, fractional loss) may rest on invalid assumptions and should be regarded with caution.
Phospholipase A
2
Type II Binds to Extracellular Matrix Biglycan
Authors: Sartipy Peter , Bondjers Göran , Hurt-Camejo Eva
Published: June 2011

Abstract
—We recently reported the presence of secretory, nonpancreatic phospholipase A
2
type II (snpPLA
2
; EC
3.1.1.4
) in human atherosclerotic arteries (Hurt-Camejo et al,
Arterioscler Thromb Vasc Biol.
1997;17:300–309). SnpPLA
2
may generate the proinflammatory products lysophospholipids and free fatty acids, thus contributing to atherogenesis when acting on low density lipoproteins (LDLs) retained in the arterial wall. Immunohistochemical studies showed that smooth muscle cells (SMCs) in human arterial tissue are the main sources of snpPLA
2
. In cultures of human arterial SMCs, snpPLA
2
interacts with versican and smaller heparan/chondroitin sulfate proteoglycans (PGs) secreted as soluble components into the medium. In the present study, we investigated the binding of snpPLA
2
to extracellular matrix (ECM) PGs produced by SMCs. The results show that snpPLA
2
can bind to the ECM at physiological salt concentrations. ECM-bound snpPLA
2
was active, hydrolyzing phosphatidylcholine-containing micelles. Soluble chondroitin-6-sulfate at concentrations >1 μmol/L, but not heparin or heparan sulfate, was able to release ECM-bound snpPLA
2
. The PG mainly involved in the binding of snpPLA
2
was identified as biglycan. Perlecan was also present in the ECM synthesized by SMCs, but it contributed less to the binding of snpPLA
2
. Experiments with immobilized glycosaminoglycans indicated that snpPLA
2
hydrolyzed 7-fold more LDL phospholipids when the lipoprotein and the enzyme were colocalized in a matrix with chondroitin-6-sulfate compared with one with heparin. These data suggest that retention of snpPLA
2
in ECMs of different composition may modulate the enzymatic activity of snpPLA
2
toward LDL. The results presented in this work support the hypothesis of the potential contribution of snpPLA
2
to atherosclerosis.
Immunization of LDL Receptor–Deficient Mice With Homologous Malondialdehyde-Modified and Native LDL Reduces Progression of Atherosclerosis by Mechanisms Other Than Induction of High Titers of Antibodies to Oxidative Neoepitopes
Authors: Freigang Stefan , Hörkkö Sohvi , Miller Elizabeth , Witztum Joseph L. , Palinski Wulf
Published: June 2011

Abstract—We and others previously showed that immunization of rabbits with different forms of oxidized low density lipoprotein (LDL) significantly reduced atherogenesis. We now investigated the effect of continued immunization on atherosclerosis in LDL receptor–deficient (LDLR−/−) mice to determine whether a similar reduction of atherosclerosis occurred in murine models and whether this was due to humoral immune responses, ie, formation of high titers of antibodies to oxidation-specific epitopes. Three groups of LDLR−/−mice were repeatedly immunized with homologous malondialdehyde-modified LDL (MDA-LDL), native LDL, or phosphate-buffered saline (PBS) for 7 weeks. Extensive hypercholesterolemia and accelerated atherogenesis were then induced by feeding a cholesterol-rich diet for 17 weeks, during which immunizations were continued. Binding of immunoglobulin (Ig) M and IgG antibodies, as well as IgG1 and IgG2a isotypes, to several epitopes of oxidized LDL were followed throughout the study. After 24 weeks of intervention, atherosclerosis in the aortic origin was significantly reduced by 46.3% and 36.9% in mice immunized with MDA-LDL and native LDL, respectively, compared with PBS (133 558 and 157 141 versus 248 867 μm2per section, respectively). However, the humoral immune response to oxidative neoepitopes in the MDA-LDL group was very different from that of the LDL or PBS group. IgG antibody binding to MDA-LDL and other epitopes of oxidized LDL, such as oxidized phospholipid (cardiolipin), oxidized cholesterol, or oxidized cholesteryl linoleate, but not native LDL, increased markedly in mice immunized with MDA-LDL, but not in mice immunized with native LDL or PBS. In the MDA-LDL group, both T helper cell (Th)2–dependent IgG1 antibody and Th1-dependent IgG2a antibody binding to oxidative neoepitopes increased significantly over time. The fact that mice immunized with both MDA-LDL and native LDL had a significant reduction in atherosclerosis, whereas only the MDA-LDL group developed very high titers of antibodies to oxidation-specific epitopes, suggests that the antiatherogenic effect of immunization is not primarily dependent on very high titers of antibodies to oxidation-specific epitopes but is more likely to result from the activation of cellular immune responses.
Factors of the Metabolic Syndrome
Authors: Leyva Francisco , Godsland Ian F. , Worthington Melek , Walton Christopher , Stevenson John C.
Published: June 2011

Abstract
—Syndromes of risk factor disturbance may contribute to the development of coronary heart disease and non–insulin-dependent diabetes mellitus, but their definition and quantification remain problematic. Using factor analysis, constellations of risk factor variables that could indicate distinct syndromes of metabolic disturbance were explored in the baseline data of the first follow-up cohort of 742 men from the Heart Disease and Diabetes Risk Indicators in a Screened Cohort (HDDRISC) study. The primary analysis considered 16 intercorrelated variables measured in more than 90% of cohort participants. A missing-values estimation routine was used to ensure inclusion of all participants in the analysis. Subanalyses were undertaken, including a repeat of the primary analysis on the 522 individuals who had received measurement of HDL cholesterol, an oblique rather than orthogonal factor rotation procedure performed on primary and HDL subset analyses, a repeat of these two primary and HDL subset analyses using only those participants with complete measurements, and a repeat of these six analyses including only the seven variables conventionally associated with the metabolic syndrome. The principal factor that emerged in all analyses undertaken comprised oral glucose tolerance test insulin and glucose response, serum uric acid, and body mass index. Fasting serum triglyceride concentration was included in this factor in 11 of the 12 analyses undertaken, fasting plasma insulin in 8, fasting plasma glucose in 5, and mean arterial pressure in 3. HDL cholesterol factored in isolation from insulin in all analyses undertaken. These findings provide strong support for a core metabolic cluster, which is unlikely to include blood pressure and does not include HDL. The factor scores relating to this cluster will provide a means of assessing its quantitative importance in prospective analysis of the development of CHD and diabetes in this cohort.
Evidence Against Linkage of Familial Combined Hyperlipidemia to the Apolipoprotein AI-CIII-AIV Gene Complex
Authors: Wijsman Ellen M. , Brunzell John D. , Jarvik Gail P. , Austin Melissa A. , Motulsky Arno G. , Deeb Samir S.
Published: June 2011

Abstract—Familial combined hyperlipidemia (FCHL) was originally described as a disorder characterized by elevated levels of either plasma cholesterol or triglyceride (TG) or both in members of the same family. More recent studies have indicated that apolipoprotein B levels (apoB) are also elevated in these individuals. Although a dominant mode of inheritance was originally proposed, recent studies have questioned this simple mode of inheritance, and the genetic basis of the disorder has eluded investigators. A study that reported evidence that FCHL is linked to the apolipoprotein AI-CIII-AIV region on chromosome 11 is therefore of interest. We have attempted to replicate this finding in three large, well-characterized FCHL kindreds by using a highly polymorphic marker in the apoCIII gene. Using the same definitions and parameters as were used in the initial report, we obtained strong evidence against linkage of FCHL to the apolipoprotein AI-CIII-AIV region on chromosome 11 (combined lod score of −7.87 at 0% recombination). Two other models, one based on total cholesterol (TC) levels alone and one based on the joint distribution of TC and apoB levels, also gave evidence against linkage of FCHL to this region (lod scores at 0% recombination of −8.95 and −2.58, respectively). An additional regression-based linkage analysis also gave no support for the existence of a locus in this region that influences these lipid levels in these pedigrees. Explanations for the differences in results between these studies include genetic heterogeneity, differences in clinical phenotype used to select the pedigrees, and ascertainment bias.
Physical Exertion Induces Thrombin Formation and Fibrin Degradation in Patients With Peripheral Atherosclerosis
Authors: Mustonen Pirjo , Lepäntalo Mauri , Lassila Riitta
Published: June 2011

Abstract
—Sudden extreme physical stress is associated with an increased risk of myocardial infarction mainly in people with preexisting atherosclerosis. In this study we compared the effect of submaximal exercise on coagulation and fibrinolysis in patients with peripheral arterial occlusive disease (PAOD) with that in healthy control subjects. Fifteen PAOD patients with intermittent claudication and 15 healthy control subjects, matched for age, sex, medication use, smoking habit, and conditioning, were studied. Thrombin–antithrombin III complex (TAT),
d
-dimer, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI)-1 antigens (Ag), t-PA activity, and plasmin-α
2
–antiplasmin complex (PAP), as well as plasma catecholamines, were measured before and after a treadmill exercise test. At rest, fibrinogen (3.3±0.5 versus 2.9±0.5 g/L [mean±SD];
P
<.05),
d
-dimer (392±128 versus 271±113 ng/mL;
P
<.05), t-PA Ag (9.1±5.1 versus 5.5±1.2 ng/mL;
P
<.02), and PAI-1 Ag (14.9±7.1 versus 7.6±3.8 ng/mL;
P
<.002) levels in plasma were markedly higher in the patient group than in the control group. In patients but not in control subjects, exercise of similar intensity elevated circulating concentrations of TAT (from 3.43±1.45 to 4.83±2.27 ng/mL;
P
<.05). Exercise caused a parallel increase in
d
-dimer, t-PA Ag, t-PA activity, PAP, and catecholamines in both groups, whereas PAI-1 Ag remained stable. Plasma lactic acid was significantly higher in patients after exercise and was associated with lower-limb ischemia. Compared with healthy control subjects, patients with PAOD showed higher t-PA Ag, PAI-1 Ag, and
d
-dimer levels both at rest and after exercise. Notably, submaximal exercise on a treadmill enhanced thrombin formation in patients with PAOD but not in the control subjects. Sudden catecholamine release and local ischemia during exercise may accelerate the preexisting prothrombotic potential of the atherosclerotic vessel wall.
Differences in Prevalence of and Risk Factors for Subclinical Vascular Disease Among Black and White Participants in the Cardiovascular Health Study
Authors: Kuller Lewis , Fisher Lloyd , McClelland Robyn , Fried Linda , Cushman Mary , Jackson Sharon , Manolio Teri
Published: June 2011

Abstract—A composite measure of subclinical vascular disease has been developed in the Cardiovascular Health Study (CHS). In previous reports, we measured the prevalence of subclinical disease among the original 5201 participants in the CHS, the relationship of risk factors to subclinical disease, and the association of subclinical disease to clinical coronary heart disease. In 1992 to 1993 (year 4 of the study), a larger cohort of 424 black women and 248 black men was added to the study. In this study, we have compared the prevalence of subclinical disease among blacks and whites in the CHS and the association with cardiovascular risk factors. The prevalence of subclinical disease for all participants (aged ≥65 years) was 41.3% for white women, 39.7% for black women, 41.9% for white men, and 43.7% for black men. The prevalence increased with age. The risk factor associations for subclinical disease were similar among blacks and whites. In multivariate analysis, age, systolic blood pressure, LDL cholesterol, smoking, and family history of myocardial infarction were independently associated with subclinical disease among both black and white women, while for white men, systolic blood pressure, use of antihypertensive medication, smoking, body mass index, and diastolic blood pressure (inverse) were related to subclinical disease. In black men, blood triglyceride level, use of antihypertensive medications, and family history of myocardial infarction (inverse) were associated with subclinical disease.
Vitamin Supplementation Reduces Blood Homocysteine Levels
Authors: den Heijer Martin , Brouwer Ingeborg A. , Bos Gerard M. J. , Blom Henk J. , van der Put Nathalie M. J. , Spaans Anja P. , Rosendaal Frits R. , Thomas Chris M. G. , Haak Hans L. , Wijermans Pierre W. , Gerrits Wim B. J.
Published: June 2011

Abstract
—Hyperhomocysteinemia is a risk factor for atherosclerosis and thrombosis and is inversely related to plasma folate and vitamin B12 levels. We assessed the effects of vitamin supplementation on plasma homocysteine levels in 89 patients with a history of recurrent venous thrombosis and 227 healthy volunteers. Patients and hyperhomocysteinemic (homocysteine level >16 μmol/L) volunteers were randomized to placebo or high-dose multivitamin supplements containing 5 mg folic acid, 0.4 mg hydroxycobalamin, and 50 mg pyridoxine. A subgroup of volunteers without hyperhomocysteinemia was also randomized into three additional regimens of 5 mg folic acid, 0.5 mg folic acid, or 0.4 mg hydroxycobalamin. Before and after the intervention period, blood samples were taken for measurements of homocysteine, folate, cobalamin, and pyridoxal-5′-phosphate levels. Supplementation with high-dose multivitamin preparations normalized plasma homocysteine levels (≤16 μmol/L) in 26 of 30 individuals compared with 7 of 30 in the placebo group. Also in normohomocysteinemic subjects, multivitamin supplementation strongly reduced homocysteine levels (median reduction, 30%; range, −22% to 55%). In this subgroup the effect of folic acid alone was similar to that of multivitamin: median reduction, 26%; range, −2% to 52% for 5 mg folic acid and 25%; range, −54% to 40% for 0.5 mg folic acid. Cobalamin supplementation had only a slight effect on homocysteine lowering (median reduction, 10%; range, −21% to 41%). Our study shows that combined vitamin supplementation reduces homocysteine levels effectively in patients with venous thrombosis and in healthy volunteers, either with or without hyperhomocysteinemia. Even supplementation with 0.5 mg of folic acid led to a substantial reduction of blood homocysteine levels.
Immunohistochemical Demonstration of Enzymatically Modified Human LDL and Its Colocalization With the Terminal Complement Complex in the Early Atherosclerotic Lesion
Authors: Torzewski Michael , Klouche Mariam , Hock Johann , Meßner Martina , Dorweiler Bernhard , Torzewski Jan , Gabbert Helmut Erich , Bhakdi Sucharit
Published: June 2011

Abstract—
Treatment of low density lipoprotein (LDL) with degrading enzymes transforms the molecule to a moiety that is micromorphologically indistinguishable from lipoproteinaceous particles that are present in atherosclerotic plaques, and enzymatically modified LDL (E-LDL), but not oxidized LDL (ox-LDL), spontaneously activates the alternative complement pathway, as do lesion lipoprotein derivatives. Furthermore, because E-LDL is a potent inducer of macrophage foam cell formation, we propose that enzymatic degradation may be the key process that renders LDL atherogenic. In this article, we report the production of two murine monoclonal antibodies recognizing cryptic epitopes in human apolipoprotein B that become exposed after enzymatic attack on LDL. One antibody reacted with LDL after single treatment with trypsin, whereas recognition by the second antibody required combined treatment of LDL with trypsin and cholesterol esterase. In ELISAs, both antibodies reacted with E-LDL produced in vitro and with lesion complement activator derived from human atherosclerotic plaques, but they were unreactive with native LDL or ox-LDL. The antibodies stained E-LDL, but not native LDL or ox-LDL, that had been artificially injected into arterial vessel walls. With the use of these antibodies, we have demonstrated that early human atherosclerotic coronary lesions obtained at autopsy as well as lesions examined in freshly explanted hearts always contain extensive extracellular deposits of E-LDL. Terminal complement complexes, detected with a monoclonal antibody specific for a C5b-9 neoepitope, colocalized with E-LDL within the intima, which is compatible with the proposal that subendothelially deposited LDL is enzymatically transformed to a complement activator at the earliest stages in lesion development.