bluuebunny/crossref_metadata_2025 huggingface dataset:
Gender Differences in Intima-Media Permeability to Low-Density Lipoprotein at Atherosclerosis-Prone Aortic Sites in Rabbits
Authors: Schwenke Dawn C.
Published: June 2011

Abstract
Premenopausal women are protected from coronary heart disease, and premenopausal nonhuman primates are protected from atherosclerosis, the underlying cause of coronary heart disease. Estrogen is thought to account for this protection in females, and part of this protection is independent of the effects on risk factors, including lipoprotein levels. This study considered the hypothesis that reduced intima-media permeability to low-density lipoproteins (LDL) may account for the protection from atherosclerosis and coronary heart disease in premenopausal females and that this effect might be mediated by estrogen. Intima-media permeability to LDL was determined in male and female rabbits made hypercholesterolemic by feeding them 0.5% cholesterol for 8 days. The diet of half of the female rabbits was supplemented with 17β-estradiol (4 mg/d) during cholesterol feeding and the preceding 4 weeks. Estrogen treatment in the female rabbits did not influence the intima-media permeability to LDL. However, intima-media permeability to LDL for branch sites of the abdominal aorta and aortic arch (regions highly susceptible to atherosclerosis) was 43% and 38% lower, respectively, in male rabbits than in female rabbits: (2.93±0.39 μL/h/g, (n=8), vs 6.28±0.86 μL/h/g, (n=16),
P
<.001, and 4.69±0.28 μL/h/g, (n=8) vs 7.57±0.75 μL/h/g, (n=16),
P
<.02). In contrast, intima-media permeability to LDL in 7 of 8 aortic sites relatively resistant to atherosclerosis did not differ between male and female rabbits. These data suggest that the protection from atherosclerosis associated with female sex and estrogen is mediated by mechanism(s) other than reduction in intima-media permeability to LDL.
Lifetime Smoking Exposure Affects the Association of C-Reactive Protein with Cardiovascular Disease Risk Factors and Subclinical Disease in Healthy Elderly Subjects
Authors: Tracy Russell P. , Psaty Bruce M. , Macy Elizabeth , Bovill Edwin G. , Cushman Mary , Cornell Elaine S. , Kuller Lewis H.
Published: June 2011

AbstractBlood levels of C-reactive protein (CRP), a marker of inflammation, are related to cardiovascular disease risk. To determine cross-sectional correlates in the elderly, we measured CRP in 400 men and women older than 65 years and free of clinical cardiovascular disease at baseline as part of the Cardiovascular Health Study. Only 2% of the values were greater than 10 mg/L, the cut-point usually used to identify inflammation. CRP levels appeared tightly regulated, since there were strong bivariate correlations between CRP and the following: inflammation-sensitive proteins such as fibrinogen (r=.52); measures of fibrinolysis such as plasmin-antiplasmin complex (r=.23); pack-years of smoking (r=.30); and body mass index (r=.24; allPvalues≤.001). The association with pack-years was independent of the length of time since cessation of smoking. CRP levels were also associated with coagulation factors VIIc, IXc, and Xc; HDL cholesterol (negative) and triglyceride; diabetes status; diuretic use; ECG abnormalities; and level of exercise. Because of effect modification, two multiple linear regression prediction models were developed for CRP, one each for never smokers and ever smokers. An a priori physiologic model was used to guide these analyses, which disallowed the use of other inflammation-sensitive variables such as fibrinogen. In never smokers, the independent predictors were body mass index (+), diabetes status (+), plasmin-antiplasmin complex (+), and the presence of ECG abnormalities (+); this model predicted 15% of the CRP population variance. In ever smokers, the predictors were body mass index (+), plasmin-antiplasmin complex (+), pack-years of smoking (+), HDL cholesterol (−), and ankle-arm blood pressure index (−); this model predicted 42% of the population variance. We conclude that levels of CRP in the healthy elderly are tightly regulated and reflect lifetime exposure to smoking as well as level of obesity, ongoing level of fibrinolysis, diabetes status, and level of subclinical atherothrombotic disease. Moreover, exposure to smoking affects the relation of CRP to these other factors.
DNA Fragmentation and Ultrastructural Changes of Degenerating Cells in Atherosclerotic Lesions and Smooth Muscle Cells Exposed to Oxidized LDL in Vitro
Authors: Jovinge Stefan , Crisby Milita , Thyberg Johan , Nilsson Jan
Published: June 2011

Abstract
Degeneration of smooth muscle cells in the fibrous cap of atherosclerotic lesions is an important factor in plaque rupture. Recent studies have suggested that many plaque cells are in a process of apoptosis as determined by positive deoxyribonucleotide-transferase-mediated dUTP end labeling. In this study, we demonstrate the existence of a colocalization between deoxyribonucleotide-transferase-mediated dUTP end labeling-positive smooth muscle cells and oxidized LDL immunoreactivity in human carotid plaques. Oxidized LDL was found to induce deoxyribonucleotide-transferase-mediated dUTP end labeling positivity in cultured human smooth muscle cells, but only in the presence of tumor necrosis factor-α and interferon-γ. Electron microscopic analysis of cultured smooth muscle cells exposed to oxidized LDL in the absence of cytokines demonstrated cytoplasmic swelling and disruption of the plasma membrane, suggesting cell death by oncosis. Cells exposed to both oxidized LDL and cytokines were characterized by chromatin and cytoplasmic condensation compatible with cell death by apoptosis. These findings further support the notion that oxidized lipids play a role in plaque cell death.
Expression of Phospholipase A
2
Isoforms in Human Normal and Atherosclerotic Arterial Wall
Authors: Elinder Liselotte Schäfer , Dumitrescu Alexandra , Larsson Pontus , Hedin Ulf , Frostegård Johan , Claesson Hans-Erik
Published: June 2011

Abstract
LDL particles must be modified in the arterial wall to be taken up by macrophages at an excessive rate, leading to foam cell formation. Phospholipase A
2
(PLA
2
) has been shown to modify LDL particles in vitro by degrading its phospholipids, resulting in enhanced uptake by macrophages. Reaction products of PLA
2
are lysophospholipids and nonesterified fatty acids (mainly arachidonic acid), which are precursors of potent inflammatory mediators and which have been found in atherosclerotic regions of the arterial wall. To elucidate the expression of PLA
2
in normal and diseased arteries, frozen tissue sections of human nonatherosclerotic mesenteric artery and carotid plaques were examined by immunohistochemistry using specific antibodies against secretory PLA
2
types I and II and cytosolic PLA
2
(85 kd). Secretory PLA
2
type I was not detected. High expression of secretory PLA
2
type II was found throughout the media in both normal and atherosclerotic artery specimens, in which smooth muscle cells dominated. Cytosolic PLA
2
was found exclusively in diseased artery, mainly in the intima in regions with an inflammatory infiltrate consisting of macrophages and smooth muscle cells. Furthermore, both normal and atherosclerotic artery possessed substantial PLA
2
activity. It is suggested that secretory PLA
2
type II could play an important role in early atherogenesis because it is present in the preatherosclerotic arterial wall, where it may lead to LDL modification, foam cell formation, and activation of immune mechanisms.
A Partial Estrogen Receptor Agonist With Strong Antiatherogenic Properties Without Noticeable Effect on Reproductive Tissue in Cholesterol-Fed Female and Male Rabbits
Authors: Holm Pernille , Shalmi Michael , Korsgaard Niels , Guldhammer Birgitte , Skouby Sven O. , Stender Steen
Published: June 2011

Abstract
Estrogen replacement therapy retards the development of cardiovascular disease and osteoporosis in postmenopausal women. However, long-term unopposed use increases the risk of cancer in endometrium and possibly in breast. The racemic compound ormeloxifene, widely used in India as an antifertility agent, is a partial estrogen receptor agonist with antiosteoporotic properties. The present study was undertaken to investigate the effect of the
l
-enantiomer (levormeloxifene) and the
d
-enantiomer (
d
-ormeloxifene) on the development of atherosclerosis. In a short-term experiment (6 weeks), 4×10 ovariectomized female rabbits were fed a 0.25% cholesterol-enriched diet and the effect on plasma cholesterol levels was studied. In a long-term experiment (13 weeks), 4×15 ovariectomized female and 4×15 sham-operated male rabbits were maintained at a similar plasma cholesterol level of 25 mmol/L and the effect on undamaged and balloon-injured arterial wall was studied. In both experiments, the rabbits were treated with levormeloxifene,
d
-ormeloxifene, 17β-estradiol, or placebo, respectively.

In the short-term experiment, levormeloxifene, in contrast to
d
-ormeloxifene, significantly reduced plasma cholesterol by 30% compared with the placebo group. In the long-term experiment, levormeloxifene, in contrast to
d
-ormeloxifene, significantly reduced atherosclerosis by 50% in the undamaged arterial wall of both female and male rabbits. Because these rabbits were cholesterol-clamped, the antiatherogenic effect was not mediated via plasma cholesterol lowering. Like estrogen, levormeloxifene did not inhibit atherosclerosis in the endothelium-denuded site of aorta. The antiatherogenic effects of levormeloxifene were thus similar to those of estrogen, but produced in the absence of any noticeable estrogenic effect on uterine or testicular tissue.
Atherosclerosis, Vascular Remodeling, and Impairment of Endothelium-Dependent Relaxation in Genetically Altered Hyperlipidemic Mice
Authors: Bonthu Srinivas , Heistad Donald D. , Chappell David A. , Lamping Kathryn G. , Faraci Frank M.
Published: June 2011

Abstract
We examined the vascular structure and endothelium-dependent relaxation in two genetic models of hypercholesterolemia: apolipoprotein E (apoE)-knockout mice and combined apoE/LDL receptor–double-knockout mice. Intimal area was increased markedly in proximal segments of thoracic aortas from apoE/LDL receptor–knockout mice [0.13±0.03 (mean±SE) mm
2
] compared with normal (C57BL/6J) mice (0.002±0.002 mm
2
,
P
<.05). Despite intimal thickening, the vascular lumen was not smaller in the aortas of apoE/LDL receptor–knockout mice (0.52±0.03 mm
2
) than in normal mice (0.50±0.03 mm
2
). In apoE-deficient mice, intimal thickening was minimal or absent, even though the concentration of plasma cholesterol was only modestly less than that in the double-knockout mouse (14.9±1.1 vs 18.0±1.2 mmol/L, respectively,
P
<.05). Relaxation of the aorta was examined in vitro in vascular rings precontracted with U46619. In normal mice, acetylcholine produced relaxation, which was markedly attenuated by the nitric oxide synthase inhibitor
N
G
-nitro-
l
-arginine (100 μM). Relaxation to acetylcholine and the calcium ionophore A23187 was normal in apoE-deficient mice (in which lesions were minimal) but greatly impaired in the proximal segments of thoracic aortas of apoE/LDL receptor–deficient mice, which contained atherosclerotic lesions. Vasorelaxation to nitroprusside was similar in normal and apoE-knockout mice, with modest but statistically significant impairment in atherosclerotic segments of apoE/LDL receptor–knockout mice. In distal segments of the thoracic aorta of apoE/LDL receptor–deficient mice, atherosclerotic lesions were minimal or absent, and the endothelium-dependent relaxation to acetylcholine and calcium ionophore was normal. Thus, in apoE/LDL receptor–knockout mice (a genetic model of hyperlipidemia), there is vascular remodeling with preservation of the aortic lumen despite marked intimal thickening, with impairment of endothelium-dependent relaxation to receptor- and nonreceptor-mediated agonists. Atherosclerosis may be accelerated in the apoE/LDL receptor–double-knockout mouse compared with the apoE-knockout strain alone. We speculate that other factors, such as the absence of LDL receptors, may contribute to the differences in the extent of atherosclerosis in these two models of hyperlipidemia.
High-Density Lipoprotein-Binding Protein (HBP)/Vigilin Is Expressed in Human Atherosclerotic Lesions and Colocalizes With Apolipoprotein E
Authors: Chiu Diane S. , Oram John F. , LeBoeuf Renee C. , Alpers Charles E. , O’Brien Kevin D.
Published: June 2011

Abstract
Accumulation of cholesteryl esters within cells of the arterial intima is a hallmark of atherosclerosis. A small number of proteins have been shown in vitro to be upregulated by cellular cholesterol loading, including apolipoprotein E (apoE) and the recently cloned HDL-binding protein (HBP), but only apoE has been shown to be upregulated in cholesterol-loaded cells in atherosclerosis. To determine whether HBP (also called vigilin) might be expressed in human atherosclerosis, immunohistochemistry and in situ hybridization were performed on coronary arteries of 18 patients. HBP/vigilin was detected on all endothelial cells. HBP/vigilin mRNA and protein also were detected on a subset of macrophages and occasionally on smooth muscle cells (SMC) in atherosclerotic plaques but were not detected on these cell types in nondiseased coronary intima. The majority of HBP/vigilin-expressing macrophages were foam cells, but HBP/vigilin expression also was detected rarely in nonfoam cell macrophages. Foam cell macrophage HBP/vigilin expression was present in 100% of atherosclerotic quadrants, and nonfoam cell macrophage HBP/vigilin expression was present in 6% of atherosclerotic quadrants. HBP/vigilin-expressing human plaque cells also expressed apoE. However, HBP/vigilin was detected in cardiac myocyte foam cells of an apoE-deficient mouse, demonstrating that HBP/vigilin expression can occur independently of apoE. These results suggest that in vivo HBP/vigilin expression is upregulated by intracellular cholesterol loading but also that other factors present in atherosclerotic plaques may upregulate HBP/vigilin. Although the exact function of HBP/vigilin is unknown, its expression in plaque macrophages suggests a role for this molecule in atherogenesis.
Scavenger Receptors are Present on Rabbit Aortic Endothelial Cells In Vivo
Authors: Daugherty Alan , Cornicelli Joseph A. , Welch Kathryn , Sendobry Sandra M. , Rateri Debra L.
Published: June 2011

Abstract
Endothelial cells metabolize modified LDL, but attempts to detect scavenger receptors in this cell type in vitro have been unsuccessful. To determine whether scavenger receptors are present on endothelial cells in vivo, species-specific reagents were developed to detect rabbit scavenger receptor protein. Antiserum against the rabbit scavenger receptor was generated with the use of synthetic peptides of two distinct regions: residues 3 to 21 in the cytoplasmic tail and residues 282 to 304 in the collagen-like region. Reactivity of antiserum against the synthetic peptides was confirmed with an enzyme-linked immunosorbent assay. Positive reactivity was also observed against fragments of scavenger receptor protein expressed in bacteria. Antiserum to both regions reacted with liver membrane proteins of sizes consistent with the scavenger receptor, as confirmed by Western blotting under reduced and nonreduced conditions. Immunocytochemical examination of rabbit aortic tissue by use of antiserum to both regions of scavenger receptor protein produced striking and identical patterns of staining of aortic endothelium. Immunostaining was abolished for both antisera by preadsorption with the specific peptide region used as immunogen. In contrast, incubation of scavenger receptor antiserum with a peptide of a region of the rabbit LDL receptor failed to influence immunoreactivity against endothelium. These data demonstrate the presence of scavenger receptors in rabbit endothelium in vivo, which may have fundamental implications for lipoprotein metabolism by the arterial wall.
Soy Protein Versus Soy Phytoestrogens in the Prevention of Diet-Induced Coronary Artery Atherosclerosis of Male Cynomolgus Monkeys
Authors: Anthony Mary S. , Clarkson Thomas B. , Bullock Bill C. , Wagner Janice D.
Published: June 2011

Abstract
Soy protein, long recognized as having cardiovascular benefits, is a rich source of phytoestrogens (isoflavones). To distinguish the relative contributions of the protein moiety versus the alcohol-extractable phytoestrogens for cardiovascular protection, we studied young male cynomolgus macaques fed a moderately atherogenic diet and randomly assigned to three groups. The groups differed only in the source of dietary protein, which was either casein/lactalbumin (casein, n=27), soy protein with the phytoestrogens intact (soy
+
, n=27), or soy protein with the phytoestrogens mostly extracted (soy
−
, n=28). The diets were fed for 14 months. Animals fed soy
+
had significantly lower total and LDL plus VLDL cholesterol concentrations compared with the other two groups. The soy
+
animals had the highest HDL cholesterol concentrations, the casein group had the lowest, and the soy
−
group was intermediate. A subset was necropsied for atherosclerosis evaluations (n=11 per group). Morphometric and angiochemical measures were done to quantify atherosclerosis. Coronary artery atherosclerotic lesions were smallest in the soy
+
group (90% less coronary atherosclerosis than the casein group and 50% less than the soy
−
group), largest in the casein group, and intermediate in the soy
−
group. The effects of the diets on lesion size and arterial lipid measures of the peripheral arteries were similar to those in the coronary arteries, with greatest prevention of atherogenesis with soy
+
and intermediate benefit with soy
−
relative to casein. We could not determine whether the beneficial effects seen in the soy
−
group relate to the protein itself or to the remaining traces of phytoestrogens. The beneficial effects of soy protein on atherosclerosis appear to be mediated primarily by the phytoestrogen component. Testicular weights were unaffected by the phytoestrogens.
Antiatherogenic Effects of a Novel Lipoprotein Lipase-Enhancing Agent in Cholesterol-Fed New Zealand White Rabbits
Authors: Chiba Tsuyoshi , Miura Shinji , Sawamura Fusae , Uetsuka Reiko , Tomita Isao , Inoue Yasuhide , Tsutsumi Kazuhiko , Tomita Takako
Published: June 2011

Abstract
Following our report that administration of 4-diethoxyphosphorylmethyl-N-(4-bromo-2-cyanophenyl) benzamide (NO-1886) to rats elevated postheparin lipoprotein lipase (LPL) activity through an increase in the enzyme mass, we now investigate antiatherogenic effects of NO-1886 in cholesterol-fed New Zealand White rabbits. For 20 weeks, four groups of male rabbits received regular rabbit chow (the normal control), 0.25% cholesterol-containing chow (the control), and cholesterol chow supplemented with 0.5% and 1.0% NO-1886, respectively. Postheparin LPL activity at week 10 was raised by 30% in 0.5% of the NO-1886 group and 40% in 1.0% of the NO-1886 group compared with those in the control. The area under the curve of plasma cholesterol level was not different in three cholesterol-fed groups whereas the area under the curve of HDL cholesterol was approximately twofold greater in the two NO- 1886 groups than in the control, and the area under the curve of plasma triglyceride was reduced to the level of the normal control. LPL activity was correlated with HDL cholesterol (
r
=.764, n=18) and triglyceride (
r
=−.627, n=18). Relative atheromatous area, aortic cholesterol, and triglyceride contents were reduced to approximately 25%, 60%, and 55%, respectively, of the control values by NO-1886 ingestion. Multiple regression analysis of LPL, HDL cholesterol, and triglyceride indicated that HDL cholesterol was the most powerful protector against aortic cholesterol accumulation, and triglyceride was the one to protect against the atheromatous area. We concluded that NO-1886 prevented the development of atherosclerosis through increasing LPL activity with a consequent increase in HDL cholesterol and a decrease in triglyceride without a significant influence of plasma cholesterol level.
Triggering of β1-Integrin Chain Induces Platelet Adhesion to Cultured Endothelium
Authors: Aldo Del Maschio  , Martín-Padura Inés , Bernasconi Sergio , Dejana Elisabetta
Published: June 2011

AbstractWe report here that platelets adhere to cultured endothelial cells (EC) on exposure to the integrin β1 activating monoclonal antibody (mAb) BV7. The effect of BV7 is exerted mostly on platelets rather than EC. BV7 does not induce platelet aggregation or 5-hydroxytyptamine (5-HT) release and does not increase platelet adhesion to matrix proteins. Another activating β1 mAb, Lia1/2, triggers an effect similar to BV7. Blocking antibodies to α2 and β1, but not to other integrin chains, are able to inhibit BV7-mediated adhesion. Moreover, the effect of BV7 requires active cellular metabolism and is not inhibited by platelet treatment with aspirin, by the PAF receptor antagonist BN50730, the phosphokinase C inhibitor staurosporin, or by the cAMP or cGMP enhancers prostaglandin E1 and sodium nitroprusside, respectively. Finally, BV7-mediated adhesion was enhanced by the endoperoxide analogue U46619. These data describe a novel mechanism of platelet adhesion to endothelial cells. This adhesion pathway appears to be mediated by α2β1-integrin on platelets and a still-undefined endothelial counter receptor.
Consequences of Hyperhomocyst(e)inemia on Vascular Function in Atherosclerotic Monkeys
Authors: Lentz Steven R. , Malinow M. René , Piegors Donald J. , Bhopatkar-Teredesai Monica , Faraci Frank M. , Heistad Donald D.
Published: June 2011

Abstract
Moderate elevation of plasma homocyst(e)ine is associated with increased risk for atherosclerotic vascular disease. In a previous study, we observed impaired vascular function in nonatherosclerotic monkeys with moderate hyperhomocyst(e)inemia. In this study, we tested the hypothesis that dietary intervention to lower plasma homocyst(e)ine corrects vascular dysfunction in atherosclerotic monkeys. Cynomolgus monkeys were fed an atherogenic diet that produces both hypercholesterolemia and moderate hyperhomocyst(e)inemia. After 17 months, the atherogenic diet was supplemented with B vitamins (5 mg folic acid, 400 μg vitamin B-12, and 20 mg vitamin B-6 daily) for 6 months. Total plasma homocyst(e)ine decreased from 12.8±2.8 to 3.5±0.3 μmol/L (n=9; mean±SE;
P
<.01) after vitamins were added to the diet, but plasma cholesterol remained elevated (522±63 versus 514±41 mg/dL;
P
>.05). In response to intra-arterial infusion of collagen, blood flow to the leg decreased by 30±3% and 38±5%, respectively, before and after vitamin supplementation (
P
>.05). In vivo responses of resistance vessels to endothelium-dependent vasodilators (acetylcholine or ADP) were impaired at baseline and did not improve after vitamin supplementation. In carotid artery studied ex vivo, relaxation to low doses of acetylcholine improved after vitamin supplementation, but maximal relaxation remained impaired. Ex vivo thrombomodulin anticoagulant activity was threefold higher in monkeys fed the atherogenic diet (with or without B vitamins) than in normal monkeys (
P
<.05). We conclude that normalization of plasma homocyst(e)ine is insufficient to restore normal vascular function in atherosclerotic monkeys with persistent hypercholesterolemia and that atherosclerosis, with or without hyperhomocyst(e)inemia, is associated with elevated thrombomodulin activity.
Liver LDL Receptor mRNA Expression Is Decreased in Human ApoB/CETP Double Transgenic Mice and Is Regulated by Diet as Well as the Cytokine Oncostatin M
Authors: Liu Jingwen , Zhang Y. Lynda , Spence Michael J. , Vestal Robert E. , Wallace Philip M. , Grass David S.
Published: June 2011

AbstractWe have investigated liver LDL receptor mRNA expression in nontransgenic, human cholesteryl ester transfer protein (CETP) transgenic, and human apolipoprotein (Apo) B/CETP double transgenic mice fed a normal chow diet and a high fat, high cholesterol diet (HFHC). Three weeks of HFHC feeding increased total serum cholesterol 1.5-fold in the nontransgenic, 3.1-fold in the CETP transgenic, and 3.4-fold in the ApoB/CETP double transgenic mice. To examine the liver LDL receptor mRNA expression among the different groups of mice fed the normal diet or fed the HFHC diet, we developed a quantitative reverse-transcribed polymerase chain reaction assay in which the LDL receptor mRNA level was normalized with the β-actin mRNA. The results show that on the normal chow diet, the LDL receptor mRNA expression levels were lower in the ApoB/CETP mice than in the nontransgenic mice and the human CETP transgenic mice. Liver LDL receptor gene expression was lower in all groups of mice fed the HFHC diet, with the lowest level of expression in the ApoB/CETP mice. Similar results were obtained by Northern blot analysis. In addition, we have previously shown that the cytokine oncostatin M (OM) increases LDL receptor gene expression in HepG2 cells. In this study, we used the ApoB/CETP mice as the model system to examine the in vivo activity of OM on liver LDL receptor gene expression. Our data show that OM increased the level of liver LDL receptor mRNA up to 80% to 90% when the animals were fed the HFHC diet. The results from these studies demonstrate that the expression of the liver LDL receptor in the ApoB/CETP mice is suppressed compared with nontransgenic mice and that the expression of the hepatic LDL receptor gene in these mice is subjected to the normal cholesterol feedback regulation. In addition, LDL receptor gene expression in these mice is also inducible by a positive regulator.
Shear Stress Gradients Remodel Endothelial Monolayers in Vitro via a Cell Proliferation-Migration-Loss Cycle
Authors: Tardy Y. , Resnick N. , Nagel T. , Gimbrone M.A. , Dewey C.F.
Published: June 2011

Abstract
Wall shear stress has been implicated in the genesis of atherosclerosis because a strong correlation exists between the location of developing arterial lesions and regions where particular gradients in stress occur. Studying the behavior of endothelial cells in such regions may contribute to our understanding of the disease etiology. We report the detailed migratory history of endothelial cells subjected to large shear stress gradients caused by a surface protuberance in an in vitro model system. The history of cell migration, cell division, and cell loss from the surface was continuously monitored in confluent human umbilical vein endothelial cell monolayers for 48 hours after the onset of flow. Individual cells were tracked using time-lapse video microscopy. In contrast to a uniform laminar flow field in which cells were observed to continually rearrange their relative position with no net migration, in a disturbed flow field there was a net migration directed away from the region of high shear gradient. This organized migration pattern under disturbed flow conditions was accompanied by more than a twofold increase in cell motility. In addition, cell division increased in the vicinity of the flow separation (maximum shear stress gradient of 34 dyne/cm
2
per mm) whereas cell loss was increased upstream and downstream in the regions where the shear gradient diminishes. These data suggest a steady cell proliferation-migration-loss cycle and indicate that local shear stress gradients may play a key role in the morphological remodeling of the vascular endothelium in vivo.
Familial Hypercholesterolemia in the Finnish North Karelia
Authors: Vuorio A. F. , Turtola H. , Piilahti K.-M. , Repo P. , Kanninen T. , Kontula K.
Published: June 2011

AbstractA specific mutation termed FH-North Karelia [FH-NK] accounts for almost 90% of familial hypercholesterolemia [FH] cases in the Finnish North Karelia, with a population of about 180 000. Extensive search for its presence in the entire North Karelia province revealed 340 carriers of this mutation. Other mutations of the LDL receptor [LDLR] gene accounted for 67 cases of heterozygous FH. This gives a minimum FH prevalence of 1 in 441 inhabitants in North Karelia, with the highest density of patients in the Polvijärvi commune (1 in 143 inhabitants). Old parish records, confirmation records, and tax records were used to track a common ancestor for most of the present-day North Karelian FH-NK patients in the village of Puso, located within an area where the FH prevalence today is the highest. DNA analysis indicated that 2% of the subjects aged 1 to 25 years would have been diagnosed as false-negative and 7% as false-positive FH patients on the basis of LDL cholesterol [LDL-C] determinations alone. Common genetic variations of apolipoprotein E [apoE],XbaI, polymorphism of apolipoprotein B [apoB], andPvuII polymorphism of the intact LDLR allele contributed little to serum lipid variation in established carriers of the FH-NK allele, although apoE2/4 genotype and the presence of thePvuII restriction site tended to be associated with relatively low LDL-C levels. Coronary heart disease (CHD) was present in 65 (30%) out of the 179 FH gene carriers aged ≥25 years, and 19 individuals had a previous history of acute myocardial infarction (AMI). The average age (mean±SD) at onset of CHD was 42±7 years for males and 48±11 years for females (P<.05). In stepwise logistic regression analysis carried out in carriers of the FH-NK allele, age, gender, smoking, and apoE allele E2 all emerged as independent determinants of risk of CHD or AMI. It may be concluded that the relatively high prevalence of FH patients in North Karelia province provides a unique founder population in which genetic and nongenetic factors modifying the course of FH can be effectively investigated.
Identification of the Src Family Kinases, Lck and Fgr in Platelets
Authors: Pestina Tamara I. , Stenberg Paula E. , Druker Brian J. , Steward Shirley A. , Hutson Nancy K. , Barrie Rosemary J. , Jackson Carl W.
Published: June 2011

Abstract
We have identified the Src family members, Lck and Fgr in resting human and rodent platelets and compared their subcellular distributions and tyrosine phosphorylation status to those of the other Src family kinases to gain insights into the signal transduction pathways active in maintaining platelets in the circulation. Like Fyn, Lyn, and Yes, most of Fgr and Lck was detergent-insoluble in human and rat platelets. In comparison, Src showed higher detergent solubility than the Src-related kinases. Most all human platelet Src was detergent-soluble, while that of rodent platelets was present in all detergent fractions.

We also compared the tyrosine-phosphorylation status of Lck and Fgr to other Src family members in resting platelets using immunoprecipitation and immunoblotting. All of these Src family members except Fgr exhibited substantial phosphotyrosine antibody labeling. The partitioning of these kinases, with the exception of Src, with the detergent-insoluble fraction, their tyrosine-phosphorylation status, and co-localization with endocytotic vesicles lead us to hypothesize that the Src family kinases are involved in signaling events that drive cytoskeletal reorganization and active endocytosis of plasma proteins by circulating platelets.
Independent Mechanisms for Macrophage Binding and Macrophage Phagocytosis of Damaged Erythrocytes
Authors: Sambrano Gilberto R. , Terpstra Valeska , Steinberg Daniel
Published: June 2011

AbstractThe binding and phagocytosis of oxidatively damaged red blood cells (OxRBCs) by mouse peritoneal macrophages can be inhibited by oxidatively modified LDL (OxLDL), implying some commonality at their receptor-binding domains. Studies from many different laboratories support the view that OxRBC binding is due to the disruption of plasma membrane phospholipid asymmetry and the subsequent exposure of phosphatidylserine (PS) on the outer membrane leaflet. Presumably, oxidation of LDL creates a surface structure on it in some way homologous to the PS-rich domain on OxRBCs. Apoptotic cells in some instances are also recognized because of PS exposure on the outer leaflet of the membrane, and apoptotic cells are a common feature of atherosclerotic lesions. In the present studies, the mechanisms of binding and internalization of cells recognized by virtue of their membrane PS were studied using OxRBCs or vanadate-treated erythrocytes (VaRBCs) as models. Disruption of phospholipid asymmetry with vanadate produced cells that were bound by macrophages in the same divalent cation–dependent manner as OxRBCs. However, whereas OxRBCs were rapidly phagocytosed, VaRBCs were not. Stimulation of mouse macrophages with phorbol myristate acetate resulted in a concentration-dependent induction of phagocytosis of bound VaRBCs, an effect that could be prevented by the protein kinase C inhibitor staurosporine. Because phagocytosis of OxRBCs occurred unassisted, we speculated that there must be additional membrane changes induced by oxidation (over and above the disruption of phospholipid asymmetry) that contribute to phagocytosis of OxRBCs, possibly resulting in the ligation of a distinct receptor that does not necessarily contribute to adherence. This proposal is supported by the finding that ligation of macrophage Fcγ receptors by the anti-FcγRII/RIII antibody 2.4G2 triggers the phagocytosis of bound VaRBCs. Phagocytosis is also triggered by subthreshold opsonization of VaRBC, ie, by antibody concentrations that do not by themselves cause binding and phagocytosis of native RBCs. Finally, treatment with low concentrations of glutaraldehyde, which causes membrane protein cross-linking, promotes the phagocytosis of VaRBCs, but, at the low concentration used, has little or no effect on binding and phagocytosis of native RBCs. We suggest that the internalization of damaged cells, bound because of PS exposure, requires the cooperation of a PS-binding receptor with at least one additional receptor to trigger an intracellular signaling pathway to initiate phagocytosis.
Association of Apo E Polymorphism With Plasma Lipid Levels in a Multiethnic Elderly Population
Authors: Pablos-Méndez Ariel , Mayeux Richard , Ngai Colleen , Shea Steven , Berglund Lars
Published: June 2011

Abstract
Apolipoprotein E polymorphisms are important determinants of blood lipid levels and have been associated with longevity and atherosclerosis. However, information is limited on the effects of apo E variation on the lipids of nonwhite and elderly individuals. We tested the hypothesis that apo E polymorphisms are associated with plasma lipid levels in an elderly, multiethnic population. Cross-sectional data from 1068 noninstitutionalized individuals from northern Manhattan over the age of 64 who were not on a lipid-lowering diet or drug were analyzed. The ethnic distribution was 34% African-Americans, 47% Hispanics, and 19% non-Hispanic Caucasians. In the entire group, the most prevalent apo E allele was ε3 (76%), followed by ε4 (16%) and ε2 (8%); ε4 was more prevalent in African-Americans (21%) than in non-Hispanic Caucasians (12%) or Hispanics (14%). The apo ε2 allele was the most important correlate of plasma lipids, but this association varied across ethnoracial groups. After being adjusted for age, sex, obesity, diabetes mellitus, and alcohol intake, LDL cholesterol levels declined with each apo ε2 allele by 8.8 mg/dL in Hispanics and by 25.6 and 18.1 mg/dL in non-Hispanic Caucasians and African-Americans, respectively (
P
<.001). No significant independent effect was noted for any apo E genotype on HDL cholesterol. Overall, there was a reduction in the total/HDL cholesterol ratio, per apo ε2 allele, of 0.82 in non-Hispanic Caucasians and 0.43 and 0.48 in African-American and Hispanic individuals, respectively (
P
<.05). In a multivariate model, apo ε4 did not significantly affect plasma lipid levels. Plasma triglyceride levels were inversely correlated with the number of apo ε4 alleles (175, 159, and 143 mg/dL with 0, 1, and 2 alleles, respectively;
P
=.002), and this effect increased with age. Thus, in an elderly, multiethnic population, apolipoprotein E polymorphisms were important determinants of blood lipids, with differing effects depending on ethnicity. The presence of apo ε2 was associated with lower LDL cholesterol levels and total/HDL cholesterol ratio, although apo ε genotype did not influence HDL cholesterol levels. Prospective studies are needed to test whether apo ε2 protects against incident cardiovascular disease in the elderly.
Native Macromolecular Heparin Proteoglycans Exocytosed From Stimulated Rat Serosal Mast Cells Strongly Inhibit Platelet-Collagen Interactions
Authors: Lassila Riitta , Lindstedt Ken , Kovanen Petri T.
Published: June 2011

Abstract
Mast cells, the major source of tissue heparin, line the vascular system. On stimulation, rat serosal mast cells release soluble heparin proteoglycans (HEP-PGs) of very high molecular weight (750 000). We compared the effects of HEP-PGs and standard heparins (average molecular weights, 15 000 and 5 000) on platelet-collagen interactions in vitro. In contrast with the standard heparins, HEP-PGs completely inhibited collagen-induced platelet aggregation and serotonin release in platelet-rich plasma. The inhibition caused by HEP-PGs depended on its macromolecular structure. In flowing blood, HEP-PGs also inhibited platelet deposition on a collagen-coated surface both at low and high shear rates. Although HEP-PGs did not block glycoprotein (GP) Ia/IIa-mediated platelet adhesion, they attenuated subsequent platelet activation and aggregation, as well as fibrinogen binding to platelets after collagen stimulation. HEP-PGs did not bind to platelets but bound tightly to von Willebrand factor (vWf) and enhanced its binding to collagen. Although platelet adhesion at high shear rate and vWf binding to GP Ib after ristocetin stimulation were not markedly affected, HEP-PGs reduced thrombin-induced aggregation and vWf binding to GP IIb/IIIa. These findings imply that activation of vascular mast cells with ensuing secretion of HEP-PGs may locally attenuate the thrombogenicity of matrix collagen by inhibiting its platelet-activating capacity.
Regulation of Body Adiposity and the Problem of Obesity
Authors: Schwartz Michael W. , Brunzell John D.
Published: June 2011

The hypothesis that body adiposity is homeostatically regulated is the focus of an intensive research effort, and support for this concept is rapidly growing. While generating optimism about the future of obesity treatment, these advances also bear on our current approach to the obese patient. The observation that body adiposity appears to be subject to regulation in obese as well as lean individuals suggests that common forms of obesity may result from a primary disorder of the weight-regulatory system. As a result, voluntary efforts to lower body adiposity activate compensatory responses that limit weight loss and facilitate weight regain. The use of weight-reduction strategies based on caloric restriction, therefore, effectively pits the will of the obese individual against his or her own intrinsic weight-regulatory system. Until more effective approaches to weight reduction are available, we suggest that clinical intervention should focus on patient education and strategies to limit weight gain or modestly lower weight. Since the combination of a low-fat diet with an exercise program appears to reduce the level at which body weight is regulated without active caloric restriction, this approach may be appropriate for many obese individuals.
Vastatins Inhibit Tissue Factor in Cultured Human Macrophages
Authors: Colli Susanna , Eligini Sonia , Lalli Mariagrazia , Camera Marina , Paoletti Rodolfo , Tremoli Elena
Published: June 2011

We examined the effect of fluvastatin, the first entirely synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor that is structurally different from other vastatins, on tissue factor (TF) expression in human macrophages spontaneously differentiated in culture from blood monocytes. Fluvastatin decreased TF activity in a dose-dependent manner (1 to 5 μmol/L) in both unstimulated and lipopolysaccharide-stimulated macrophages, and this reduction paralleled the decrease in immunologically recognized TF protein. The same results were obtained with another lipophilic vastatin, simvastatin, but not with hydrophilic pravastatin. The reduction in TF expression was also observed in macrophages enriched in cholesterol after exposure to 50 μg/mL acetylated low density lipoprotein. The inhibitory effect of fluvastatin on TF activity and antigen was fully reversible by coincubation with 100 μmol/L mevalonate or 10 μmol/L all-trans-geranylgeraniol but not with dolichol, farnesol, or geraniol. Suppression of TF antigen and activity was accompanied by a diminution in TF mRNA levels, which was completely prevented by mevalonate. Furthermore, fluvastatin impaired bacterial lipopolysaccharide–induced binding of c-Rel/p65 heterodimers to a κB site in the TF promoter, indicating that this drug influences induction of the TF gene. We conclude that lipophilic vastatins inhibit TF expression in macrophages, and because this effect is prevented by mevalonate and geranylgeraniol, a geranylgeranylated protein plays a crucial role in the regulation of TF biosynthesis. The suppression of TF in macrophages by vastatins indicates a potential mechanism by which these drugs interfere with the formation and progression of atherosclerotic plaque as well as thrombotic events in hyperlipidemic patients.
No Influence of Simvastatin Treatment on Platelet Function In Vivo in Patients With Hypercholesterolemia
Authors: Bröijersén Anders , Eriksson Mats , Leijd Barbro , Angelin Bo , Hjemdahl Paul
Published: June 2011

Hypercholesterolemia is associated with platelet activation. Reduction of plasma cholesterol levels by the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin has been found to improve certain aspects of platelet function in vitro and in vivo, but controlled trials are largely lacking. The present randomized, double-blind, crossover study was performed to evaluate whether 10- to 12-week treatment with simvastatin or placebo affects platelet function in vivo in 23 hypercholesterolemic men. Measurements were performed at rest and during mental stress. Simvastatin treatment reduced plasma total cholesterol levels by 18±2% and low density lipoprotein cholesterol levels by 26±2% (
P
<.001 for both), whereas high density liproprotein cholesterol levels increased slightly (6±2%,
P
<.05). Platelet aggregability as assessed by filtragometry ex vivo was unaffected by simvastatin treatment both at rest and during mental stress. Plasma β-thromboglobulin levels, which reflect platelet secretion, were also unaltered by simvastatin treatment both at rest (antilog of the mean: 20.2 versus 20.0 ng/mL during placebo) and during mental stress. Moreover, nocturnal excretion of 11-dehydrothromboxane B
2
in urine did not differ between placebo and active treatment: 218 versus 216 ng/mmol creatinine, respectively. The corresponding values for urinary excretion of high-molecular-weight β-thromboglobulin were 1.78 versus 1.92 ng/mmol creatinine. Thus, simvastatin treatment had no clear-cut effect on platelet function, as assessed by four different in vivo related platelet function variables, in hypercholesterolemic men.
Lipoprotein Lipase Correlates Positively and Hepatic Lipase Inversely With Calcific Atherosclerosis in Homozygous Familial Hypercholesterolemia
Authors: Dugi Klaus A. , Feuerstein Irwin M. , Hill Suvimol , Shih Joanna , Santamarina-Fojo Silvia , Jr H. Bryan Brewer , Hoeg Jeffrey M.
Published: June 2011

Homozygous familial hypercholesterolemia (FH) is a rare genetic disorder that leads to premature atherosclerosis due to a defective LDL receptor. There is, however, a large degree of phenotypic heterogeneity at the level of atherosclerosis even in patients with identical mutations of the LDL receptor protein. Lipoprotein lipase (LPL) and hepatic lipase (HL) are crucial enzymes in lipoprotein metabolism, and both have been proposed as having proatherogenic as well as antiatherogenic effects. To evaluate a potential role for these enzymes in the severity of atherosclerosis, we correlated postheparin LPL mass and activity as well as HL activity with the volume of total calcific atherosclerosis (heart and thoracic aorta), coronary artery calcific atherosclerosis, and Achilles tendon width as measured by computed tomography in 15 FH homozygotes. LPL dimer and total mass were positively correlated with all three parameters (
r
=.65 to .87,
P
<.01) as was LPL activity (
r
=.52 to .63,
P
<.05). HL activity was negatively correlated with total and coronary artery calcified lesion volume (
r
=−.55 to .57,
P
<.05). In a multiple regression model of the coronary artery lesion volume, LPL dimer mass and HL activity together accounted for 84% of the variability (
r
=.92,
P<
.0001). In a multiple regression model of the total calcified lesion volume, HL activity, total cholesterol, age, and LPL dimer mass together accounted for 85% of the variability (
r
=.92,
P
=.0005). These data demonstrate a significant correlation of LPL mass and activity with the extent of calcific atherosclerosis in homozygous FH. It is not clear whether LPL is the cause or consequence of the observed correlation, but if the association between LPL and coronary artery lesions is also present in patients with other genetic dyslipoproteinemias, LPL could constitute a new risk factor for cardiovascular disease.
Regulation of the Tissue Factor Gene in Human Monocytic Cells
Authors: Oeth Paul , Parry Graham C.N. , Mackman Nigel
Published: June 2011

Tissue factor (TF) expression by peripheral blood monocytes during sepsis initiates intravascular thrombosis. Bacterial lipopolysaccharide (LPS) rapidly induces TF gene transcription in monocytes. The human TF promoter contains binding sites for the transcription factors AP-1, c-Rel/p65, Egr-1, and Sp1. NF-κB/Rel proteins have been shown to physically interact with both AP-1 and Sp1 proteins. In this study, we investigated the role of these transcription factors in uninduced and LPS-induced TF gene expression in human monocytic THP-1 cells. Deletional analysis indicated that five Sp1 sites mediated basal expression in uninduced cells. The two AP-1 sites bound c-Fos/c-Jun heterodimers in both unstimulated and LPS-stimulated cells. Maximal LPS induction of the TF promoter required the two AP-1 sites and the κB site within the LPS response element. Disruption of the conserved spacing between the proximal AP-1 site and the κB site abolished LPS induction. Replacement of the two AP-1 sites with intrinsically bent DNA partially restored LPS induction, suggesting an additional structural role for the AP-1 sites. Synergistic transactivation of the LPS response element inDrosophilaSchneider cells by coexpression of c-Fos, c-Jun, c-Rel, and p65 or c-Jun and p65 required the transactivation domains of c-Jun and p65. These data indicated that c-Fos/c-Jun, c-Rel/p65, and Sp1 regulate TF gene expression in human monocytic cells.